JP7693812B2 - Catalytic carbon fiber preparation method - Google Patents

Description

Chemical processes often require multiple unit operations to produce a product stream. A particular unit operation may be a liquid-liquid contacting operation, whereby two liquids are brought into close contact resulting in mass transfer between the liquids, a reaction between components in the liquids, or both. Another unit operation may be a gas-liquid contacting operation, whereby a gas and a liquid are brought into contact resulting in mass transfer between the liquids, a reaction between components in the liquids, or both. Liquid-liquid contacting may be beneficial in some types of chemical reactions where one reactant is miscible in a first liquid but not in a second liquid. One example of such a reaction may be one where a first reactant is present in a polar solvent such as water and a second reactant is present in a non-polar solvent such as a hydrocarbon, where water and the hydrocarbon are immiscible. Liquid-liquid contacting may have other applications, such as liquid-liquid extraction, whereby a species present in a first liquid is extracted into a second liquid by mass transfer across the liquid-liquid interface. Gas-liquid contact can be useful in several types of chemical reactions in which components in the gas phase react with components in the liquid phase and gas components are absorbed into the liquid phase.

A particular challenge of liquid-liquid contactors and gas-liquid contactors, also collectively referred to as "mass transfer equipment," can be ensuring adequate contact area between the phases so that mass transfer or reaction occurs in an appropriate amount and in an economically viable manner. Generally, liquid-liquid contacting operations can be carried out with immiscible liquids, such as, for example, an aqueous liquid and an organic liquid. Using two immiscible liquids will allow the liquids to be easily separated after the liquid-liquid contacting is completed. However, when liquid-liquid contacting operations are carried out with immiscible liquids, phase separation may occur before adequate contact between the liquids is achieved.

Several mass transfer devices and techniques have been developed to enhance the contact area between phases, including but not limited to fiber bundle contactors. Fiber bundle contactors generally include one or more fiber bundles suspended within a shell and two or more inlets where phases, including gas-liquid or liquid-liquid, may be introduced into the shell. The fiber bundles promote contact between the phases by allowing a first phase to flow along the individual fibers of the fiber bundle and a second phase to flow between the individual fibers, thereby increasing the effective contact area between the phases. The two phases may flow from an inlet section of the shell to an outlet section of the shell while maintaining intimate contact such that reaction, mass transfer, or both, are maintained between the two phases.

Fiber bundle contactors have been developed to treat mercaptan sulfur-containing hydrocarbon streams. In these contactors, a liquid catalyst or solid catalyst bed may be utilized in conjunction with caustic to convert the mercaptan sulfur to disulfide oil. However, challenges exist in this process, including ensuring that the extent of reaction is sufficient so that the resulting product stream is on specification. Some ways to ensure that the extent of reaction is sufficient to produce a product stream that is on specification may be to design the mass transfer device to have a longer contact time by constructing a physically larger mass transfer device, or to design the mass transfer device with features that enhance the effect of mixing from the inlet. Although the physical characteristics of the mass transfer device can be optimized to a certain extent, there is a limit to the extent to which the reaction will proceed regardless of the physical configuration of the mass transfer device due to limitations of the oxidation catalyst.

Disclosed herein is an example method that includes oxidizing virgin carbon fiber to produce an oxidized carbon fiber; reacting the oxidized carbon fiber with a polyamine compound to produce an amine-modified carbon fiber; and reacting the amine-modified carbon fiber with an organometallic macrocycle to produce a catalytic carbon fiber.

Further disclosed herein is an example of a method that includes providing a carbon fiber and an aminated macrocycle; combining the carbon fiber and the aminated macrocycle with a solvent; and reacting the carbon fiber and the aminated macrocycle to form an amide bond between the carbon fiber and the aminated macrocycle, thereby forming a catalytic carbon fiber.

Further disclosed herein is a fiber bundle contactor that includes a flow path defined by a conduit; a catalytic carbon fiber bundle disposed in the conduit, where the catalytic carbon fiber includes an amine compound covalently bonded to the carbon fiber and an organometallic macrocycle covalently bonded to the amine compound; and an inlet that allows for fluid to flow within the flow path.

Further disclosed herein is a method including introducing into a vessel a hydrocarbon containing mercaptan sulfur, an aqueous caustic solution, and an oxidizing agent; reacting at least a portion of the mercaptan sulfur and the aqueous caustic solution to produce a mercaptide; and reacting the mercaptide and the oxidizing agent in the presence of a catalytic carbon fiber bundle to produce a disulfide oil, where the catalytic carbon fiber bundle includes carbon fiber, an amine compound covalently bonded to the carbon fiber, and an organometallic macrocycle covalently bonded to the amine compound.

These and other features and characteristics of the disclosed processes and systems and their advantageous applications and/or uses will become apparent from the detailed description that follows.

These drawings illustrate certain aspects of some embodiments of the present disclosure and should not be used to limit or define the present disclosure.

FIG. 1 is an illustrative depiction of a block flow diagram of a process for producing disulfide oils from hydrocarbon streams containing mercaptan sulfur. FIG. 2 is an illustrative depiction of a hydrocarbon desulfurization vessel containing catalyzed carbon fibers. FIG. 3 is an illustrative depiction of a hydrocarbon desulfurization vessel containing catalyzed carbon fibers. FIG. 4 is an illustrative depiction of a stand-alone caustic regeneration unit containing catalyzed carbon fiber. FIG. 5a is an illustrative depiction of a stand-alone caustic regeneration unit containing catalyzed carbon fiber. FIG. 5b is an illustrative depiction of a top view of the distributor tray.

The present disclosure relates to liquid-liquid and gas-liquid mass transfer devices, and in some embodiments, to mass transfer devices that include catalyzed carbon fibers. The catalyzed carbon fibers may include an organometallic catalyst that is chemically grafted onto the surface of the carbon fibers. The catalyzed carbon fibers may be used in liquid-liquid and gas-liquid mass transfer devices as heterogeneous catalysts.

Disclosed herein are methods of preparing catalytic carbon fibers. In some embodiments, the method of preparing catalytic carbon fibers can include a process that includes oxidizing virgin carbon fibers to produce oxidized carbon fibers, followed by amine treatment to produce amine-modified carbon fibers. The amine-modified carbon fibers are further reacted with organometallic macrocycles to produce catalytic carbon fibers. In some embodiments, the method of preparing catalytic carbon fibers can include reacting aminated macrocycles with carbon fibers in the presence of a solvent to produce catalytic carbon fibers.

Any type of carbon fiber may be utilized in the present disclosure, including, but not limited to, carbon fibers prepared using polyacrylonitrile (PAN), mesophase pitch, and rayon. Suitable carbon fibers may have any structural order or any structural order therebetween, including those carbon fibers classified as turbostratic or graphitic. The carbon fibers may be of any quality, including from about 50% carbon by weight to about 100% carbon by weight, and may have any classification, such as low modulus carbon fibers having a tensile strength modulus of less than 240 million kPa, intermediate modulus carbon fibers having a tensile strength modulus of about 240 million kPa to 500 million kPa, or high modulus carbon fibers having a tensile strength modulus of about 500 million kPa to 1 billion kPa. The carbon fibers may have any diameter, including from about 5 micrometers to about 20 micrometers, or any diameter therebetween. Carbon fiber can be in the form of a strand or bundle, whereby hundreds to thousands of individual carbon fibers can be spun together to form a carbon fiber strand or bundle.

In some embodiments, in the method of preparing catalytic carbon fibers, a first step may include oxidizing virgin carbon fibers to produce oxidized carbon fibers. The oxidation is carried out in a liquid or gas environment to form oxygen-containing functional groups on the surface of the carbon fibers. The oxygen-containing functional groups may include carboxyl, carbonyl, lactone, and hydroxyl that are covalently bonded to at least a portion of the carbon atoms producing the carbon fibers. The oxidation step oxidizes the carbon fibers to any suitable extent. Without limitation, the carbon fibers may be oxidized to include about 0.1 wt. % to about 25 wt. % oxygen-containing functional groups. Alternatively, the carbon fibers may be oxidized to include about 0.1 wt. % to about 1 wt. % oxygen-containing functional groups, about 1 wt. % to about 5 wt. % oxygen-containing functional groups, about 5 wt. % to about 10 wt. % oxygen-containing functional groups, about 10 wt. % to about 15 wt. % oxygen-containing functional groups, about 10 wt. % to about 20 wt. % oxygen-containing functional groups, about 10 wt. % to about 20 wt. % oxygen-containing functional groups, about 10 wt. % to about 20 wt. % oxygen-containing functional groups, about 10 wt. % to about 30 wt. % oxygen-containing functional groups, about 10 wt. % to about 30 wt. % oxygen-containing functional groups, about 10 wt. % to about 2 ... % oxygen-containing functional groups, about 15 wt. % to about 20 wt. % oxygen-containing functional groups, about 20 wt. % to about 25 wt. % oxygen-containing functional groups, or any range therebetween. The degree of oxidation may be used to control the final concentration of organometallic macrocycles dispersed on the catalytic carbon fiber, which in turn may directly affect the overall catalytic activity of the catalytic carbon fiber.

Oxidation of the carbon fibers may be accomplished by immersing the virgin carbon fibers in an acid and allowing the acid to react with the virgin carbon fibers. Suitable acids may include inorganic acids such as, for example, hydrochloric acid, nitric acid, phosphoric acid, sulfuric acid, boric acid, hydrofluoric acid, hydrobromic acid, perchloric acid, hydroiodic acid, fluoroantimonic acid, carborane acid, fluoroboric acid, fluorosulfuric acid, hydrogen fluoride, triflic acid, and perchloric acid, and organic acids such as, for example, acetic acid, formic acid, citric acid, oxalic acid, and tartaric acid. In addition to or instead of oxidation using acids, the oxidation step may also be carried out using plasma treatment in an oxygen atmosphere, gamma irradiation treatment, electrochemical oxidation using oxidants such as sodium hydroxide, ammonium bicarbonate, ammonium carbonate, sulfuric acid, or nitric acid, oxidation with potassium persulfate using sodium hydroxide or silver nitrate. Acid oxidation may be carried out at any temperature ranging from about 0°C to 150°C. Alternatively, the oxidation may be carried out at a temperature ranging from 0° C. to about 25° C., from about 25° C. to about 50° C., from about 50° C. to about 75° C., from about 75° C. to about 100° C., from about 100° C. to about 125° C., from about 125° C. to about 150° C., or any temperature range therebetween. The oxidation may be carried out for any period of time appropriate to achieve a desired concentration of oxygen-containing functional groups on the carbon fibers. The time required to achieve a specified concentration of oxygen-containing functional groups may depend on many factors, including the identity and concentration of the acid and the temperature conditions selected. Generally, the oxidation is carried out for a period of time ranging from about 1 hour to about 24 hours. Alternatively, the oxidation may be carried out for a period of time ranging from about 1 hour to about 3 hours, from about 3 hours to about 6 hours, from about 6 hours to about 9 hours, from about 9 hours to about 12 hours, from about 12 hours to about 15 hours, from about 15 hours to about 18 hours, from about 18 hours to about 21 hours, from about 21 hours to about 24 hours, or any range of times therebetween. After oxidation by acid treatment, the oxidized carbon fiber may optionally be washed using water or other solvent to remove excess acid. The oxidized carbon fiber may be dried at elevated temperatures after washing to remove any water or solvent used in the washing step.

The second step of preparing the catalytic carbon fiber may include producing an amine-modified carbon fiber. After the oxidized carbon fiber is produced, the oxidized carbon fiber may be reacted with an amine-containing compound to produce the amine-modified carbon fiber. The amine-containing compound may be any polyamine compound containing at least two amine groups, including diamines, triamines, and higher amines. The amine-containing compound may include linear, branched, or cyclic primary or secondary amines having carbon numbers ranging from C2 to C20. Some specific amine-containing compounds may include, but are not limited to, ethylenediamine, propane-1,3-diamine, butane-1,4-diamine, pentane-1,5-diamine, hexamethylenediamine, diethylenetriamine, benzene-1,3,5-triamine, and combinations thereof. The oxidized carbon fiber may be reacted with the amine-containing compound under any suitable conditions, including temperatures ranging from about 0°C to 250°C. Alternatively, the oxidation may be carried out at a temperature ranging from 0° C. to about 25° C., from about 25° C. to about 50° C., from about 50° C. to about 75° C., from about 75° C. to about 100° C., from about 100° C. to about 125° C., from about 125° C. to about 150° C., from about 150° C. to about 175° C., from about 175° C. to about 200° C., from about 200° C. to about 225° C., from about 225° C. to about 250° C., or any temperature range therebetween. The time required to react the oxidized carbon fiber and the amine-containing compound may depend on many factors, including the identity of the amine-containing compound and the temperature conditions selected. Generally, the oxidized carbon fiber may be reacted with the amine-containing compound for a period ranging from about 1 hour to about 24 hours. Alternatively, the oxidized carbon fiber may be run for a time ranging from about 1 hour to about 3 hours, from about 3 hours to about 6 hours, from about 6 hours to about 9 hours, from about 9 hours to about 12 hours, from about 12 hours to about 15 hours, from about 15 hours to about 18 hours, from about 18 hours to about 21 hours, from about 21 hours to about 24 hours, or any range therebetween. After reaction of the amine, the amine-modified carbon fiber may optionally be washed using water or other solvent to remove excess amine. The amine-modified carbon fiber may be dried at elevated temperature after washing to remove any water or solvent used in the washing step.

The third step of preparing the catalytic carbon fiber may include reacting the amine-modified carbon fiber with an organometallic macrocycle to produce the catalytic carbon fiber. The organometallic macrocycle may include unsubstituted metal phthalocyanines, substituted metal phthalocyanines, and combinations thereof. Suitable metal phthalocyanines may include halogen, hydroxyl, amine, alkyl, aryl, thiol, alkoxy, nitrosyl groups, or combinations thereof, substituents at one or more peripheral hydrogen atoms on the metal phthalocyanine. The metal phthalocyanines may include any suitable metal, including, but not limited to, vanadium (V), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), and combinations thereof. The organometallic macrocycles may be dispersed in a solvent, including but not limited to water, pyridine, DMSO, DMF, THF, ethanol, acetonitrile, chloroform, ethylene glycol, methanol, benzene, or combinations thereof, prior to reaction with the amine-modified carbon fibers.

The amine-modified carbon fiber may be reacted with the organometallic macrocycle under any suitable conditions, including temperatures ranging from about 0° C. to about 150° C. Alternatively, the oxidation may be carried out at temperatures ranging from 0° C. to about 25° C., from about 25° C. to about 50° C., from about 50° C. to about 75° C., from about 75° C. to about 100° C., from about 100° C. to about 125° C., from about 125° C. to about 150° C., or any temperature range therebetween. The time required to react the amine-modified carbon fiber and the amine-containing compound may depend on many factors, including the identity of the organometallic macrocycle and the temperature conditions selected. Generally, the amine-modified carbon fiber may be reacted with the organometallic macrocycle for a period ranging from about 1 hour to about 24 hours. Alternatively, the oxidation may be carried out for a time ranging from about 1 hour to about 3 hours, from about 3 hours to about 6 hours, from about 6 hours to about 9 hours, from about 9 hours to about 12 hours, from about 12 hours to about 15 hours, from about 15 hours to about 18 hours, from about 18 hours to about 21 hours, from about 21 hours to about 24 hours, or any range therebetween. After reaction of the organometallic macrocycles, the catalyzed carbon fiber may optionally be washed using water or other solvent to remove excess organometallic macrocycles. The catalyzed carbon fiber may be dried at elevated temperatures after washing to remove any water or solvent used in the washing step.

In a further embodiment, a synthesis method for producing catalytic carbon fibers may include reacting aminated macrocycles with carbon fibers in the presence of a solvent to produce catalytic carbon fibers. The aminated macrocycles may include organometallic macrocycles and amine groups grafted to the organometallic macrocycles. The amine groups may include amino groups, and imino groups, or combinations thereof. The amine groups allow the aminated macrocycles to react with oxygen-containing groups, such as carboxyl groups, on the surface of the carbon fiber to form amide bonds between the aminated macrocycles and the carbon fiber. The carbon fiber production may include an oxidative surface treatment step as described above that leaves oxygen-containing groups, such as carboxyl groups, on the surface of the carbon fiber. The concentration of oxygen-containing groups, such as carboxyl groups, may determine the amount of aminated macrocycles that can react with the carbon fiber. Further oxidative surface treatments may be utilized to increase the concentration of reactive groups, including carboxyl groups, such that the carbon fiber can react with a greater amount of aminated macrocycles.

The aminated macrocycle may comprise any suitable organometallic macrocycle, including, but not limited to, unsubstituted metallophthalocyanines, substituted metallophthalocyanines, and combinations thereof. The substituted metallophthalocyanines may comprise halogen, hydroxyl, alkyl, aryl, thiol, alkoxy, nitrosyl groups, or combinations thereof, substitutions at one or more peripheral hydrogen atoms on the metallophthalocyanine. The metallophthalocyanines may comprise any suitable metal, including, but not limited to, vanadium (V), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), and combinations thereof. The aminated macrocycle may comprise one or more amine groups ( _-NH2 or -NH) grafted to the organometallic macrocycle. The aminated macrocycle may comprise an amine-containing compound grafted to an organic macrocycle. The amine-containing compounds may include C2-C20, monoamines, diamines, triamines, and higher amines. The amine-containing compounds may include linear, branched, or cyclic amines. Some specific amine-containing compounds may include, but are not limited to, ethylenediamine, propane-1,3-diamine, butane-1,4-diamine, pentane-1,5-diamine, hexamethylenediamine, diethylenetriamine, benzene-1,3,5-triamine, and combinations thereof. Some suitable aminated macrocycles may include aminocobalt phthalocyanines, such as monoaminocobalt phthalocyanine and polyaminocobalt phthalocyanine. Polyaminocobalt phthalocyanines may include diaminocobalt phthalocyanine, triaminocobalt phthalocyanine, tetraaminocobalt phthalocyanine, and higher polyaminocobalt phthalocyanines. Other specific suitable aminated macrocycles may include porphyrins, hemes, polyaza compounds, and crown ethers.

Catalytic carbon fibers can be prepared by reacting aminated macrocycles with carbon fibers to form amide bonds between the aminated macrocycles. There are several synthetic methods for the formation of amide bonds between carbon fibers and aminated macrocycles, only some of which may be disclosed herein. One synthetic method may involve direct formation of amide bonds by reacting carbon fibers and aminated macrocycles at elevated temperatures in a suitable solvent. Another synthetic method may involve amide formation via generation of acyl chlorides from carboxylic acids using chlorinating agents such as thionyl chloride. Another synthetic method may involve amide formation using coupling agents such as carbodiimides or benzotriazoles. Another synthetic method may involve enzyme-catalyzed amide formation.

In the direct amide bond synthesis, the carbon fiber and the aminated macrocycle may be combined in a solvent and heated to form an amide bond between the carbon fiber and the aminated macrocycle to produce the catalytic carbon fiber. Some suitable solvents may include, but are not limited to, pyridine, DMSO, DMF, THF, ethanol, acetonitrile, chloroform, ethylene glycol, methanol, benzene, and combinations thereof. The carbon fiber may be reacted with the aminated macrocycle under any suitable conditions, including temperatures ranging from about 100°C to 200°C. Alternatively, the reaction may be carried out at temperatures ranging from 100°C to about 125°C, about 125°C to about 150°C, about 150°C to about 175°C, about 175°C to about 200°C, or any temperature range therebetween. The time required to react the carbon fiber and the aminated macrocycle may depend on many factors, including the identity of the aminated macrocycle and the temperature conditions selected. Generally, the carbon fibers may be reacted with the aminated macrocycles for a period ranging from about 1 hour to about 24 hours or longer. Alternatively, the reaction may be carried out for a period ranging from about 1 hour to about 3 hours, from about 3 hours to about 6 hours, from about 6 hours to about 9 hours, from about 9 hours to about 12 hours, from about 12 hours to about 15 hours, from about 15 hours to about 18 hours, from about 18 hours to about 21 hours, from about 21 hours to about 24 hours, or any range therebetween. After reaction of the aminated macrocycles, the catalyzed carbon fibers may optionally be washed using water or other solvents to remove excess aminated macrocycles. The catalyzed carbon fibers may be dried at elevated temperatures after washing to remove any water or solvent used in the washing step.

In the acyl chloride synthesis, the carbon fiber may be combined with a chlorinating agent, such as thionyl chloride, phosphorus trichloride, or terephthaloyl chloride, and heated. The chlorinating agent may react with oxygen-containing groups, such as carboxyl groups, on the carbon fiber to produce acyl chlorides on the carbon fiber. The carbon fiber may be reacted with the chlorinating agent at any suitable conditions below the boiling point of the chlorinating agent, including temperatures ranging from about 0° C. to 150° C. Alternatively, the reaction may be carried out at temperatures ranging from 0° C. to about 25° C., from about 25° C. to about 50° C., from about 50° C. to about 75° C., from about 75° C. to about 100° C., from about 100° C. to about 125° C., from about 125° C. to about 150° C., or any temperature range therebetween. Generally, the carbon fiber may be reacted with the chlorinating agent for a period ranging from about 1 hour to about 24 hours or longer. The chlorinating agent-modified carbon fiber may be reacted with aminated macrocycles to produce catalytic carbon fiber. For example, the chlorinating agent-modified carbon fiber and the aminated macrocycle may be combined in a solvent and heated, thereby forming an amide bond between the carbon fiber and the aminated macrocycle to produce a catalytic carbon fiber. Some suitable solvents may include, but are not limited to, water, pyridine, DMSO, DMF, THF, ethanol, acetonitrile, chloroform, ethylene glycol, methanol, benzene, and combinations thereof. The chlorinating agent-modified carbon fiber may be reacted with the aminated macrocycle under any suitable conditions, including temperatures ranging from about 0° C. to 150° C. Alternatively, the reaction may be carried out at temperatures ranging from 0° C. to about 25° C., from about 25° C. to about 50° C., from about 50° C. to about 75° C., from about 75° C. to about 100° C., from about 100° C. to about 125° C., from about 125° C. to about 150° C., or any temperature range therebetween. The time required to react the chlorinating agent-modified carbon fiber and the aminated macrocycle may depend on many factors, including the identity of the aminated macrocycle and the temperature conditions selected. In general, the chlorinating agent-modified carbon fiber may be reacted with the aminated macrocycle for a period ranging from about 1 hour to about 24 hours or longer. Alternatively, the reaction may be carried out for a period ranging from about 1 hour to about 3 hours, from about 3 hours to about 6 hours, from about 6 hours to about 9 hours, from about 9 hours to about 12 hours, from about 12 hours to about 15 hours, from about 15 hours to about 18 hours, from about 18 hours to about 21 hours, from about 21 hours to about 24 hours, or any range therebetween. After reaction of the aminated macrocycle, the catalyzed carbon fiber may optionally be washed using water or other solvent to remove excess aminated macrocycle. The catalyzed carbon fiber may be dried at elevated temperature after washing to remove the water or solvent used in the washing step.

Another synthesis method may include amide formation using a coupling agent. In this method, the carbon fiber and the coupling agent may be combined in a suitable solvent and heated. The coupling agent may react with oxygen-containing functional groups on the carbon fiber or the carbon fiber to form a functionalized carbon fiber. Some suitable coupling agents may include, but are not limited to, carbodiimides, benzotriazoles, and combinations thereof. The functionalized carbon fiber may be combined with an aminated macrocycle and a solvent that may react to form a catalytic carbon fiber. Some suitable solvents may include, but are not limited to, water, pyridine, DMSO, DMF, THF, ethanol, acetonitrile, chloroform, ethylene glycol, methanol, benzene, and combinations thereof. The functionalized carbon fiber may react with the aminated macrocycle under any suitable conditions, including temperatures ranging from about 0°C to 150°C. Alternatively, the reaction may be carried out at a temperature ranging from 0° C. to about 25° C., from about 25° C. to about 50° C., from about 50° C. to about 75° C., from about 75° C. to about 100° C., from about 100° C. to about 125° C., from about 125° C. to about 150° C., or any range of temperatures therebetween. The time required to react the functionalized carbon fiber and the aminated macrocycle may depend on many factors, including the identity of the aminated macrocycle and the temperature conditions selected. In general, the functionalized carbon fiber may be reacted with the aminated macrocycle for a period ranging from about 1 hour to about 24 hours or longer. Alternatively, the reaction may be carried out for a time ranging from about 1 hour to about 3 hours, from about 3 hours to about 6 hours, from about 6 hours to about 9 hours, from about 9 hours to about 12 hours, from about 12 hours to about 15 hours, from about 15 hours to about 18 hours, from about 18 hours to about 21 hours, from about 21 hours to about 24 hours, or any range of times therebetween. After reaction of the aminated macrocycles, the catalyzed carbon fibers may optionally be washed using water or other solvents to remove excess aminated macrocycles. The catalyzed carbon fibers may be dried at elevated temperatures after washing to remove any water or solvent used in the washing step.

Another synthesis method may include amide formation using enzymes. Enzymatic catalysis may allow the amination reaction to occur at relatively low temperatures, allowing for broader solvent compatibility. In this method, the carbon fiber and aminated macrocycle are combined with an enzyme in a suitable solvent. The enzyme may include any enzyme capable of catalyzing the formation of an amide bond between the carbon fiber and the aminated macrocycle. Some examples of suitable enzymes may include, but are not limited to, proteases, subtilisins, acylases, amidases, lipases, and combinations thereof. Some suitable solvents may include, but are not limited to, water, pyridine, DMSO, DMF, THF, ethanol, acetonitrile, chloroform, ethylene glycol, methanol, benzene, and combinations thereof. The carbon fiber may be reacted with the aminated macrocycle under any suitable conditions, including temperatures ranging from about 0°C to 100°C. Alternatively, the reaction may be carried out at a temperature ranging from 0° C. to about 25° C., from about 25° C. to about 50° C., from about 50° C. to about 75° C., from about 75° C. to about 100° C., or any temperature range therebetween. The time required to react the carbon fiber and the aminated macrocycle may depend on many factors, including the identity of the aminated macrocycle and the temperature conditions selected. In general, the carbon fiber may be reacted with the aminated macrocycle for a period ranging from about 1 hour to about 24 hours or longer. Alternatively, the reaction may be carried out for a period ranging from about 1 hour to about 3 hours, from about 3 hours to about 6 hours, from about 6 hours to about 9 hours, from about 9 hours to about 12 hours, from about 12 hours to about 15 hours, from about 15 hours to about 18 hours, from about 18 hours to about 21 hours, from about 21 hours to about 24 hours, or any range therebetween. After reaction of the aminated macrocycle, the catalyzed carbon fiber may be optionally washed using water or other solvent to remove excess aminated macrocycle. The catalyzed carbon fibers may be dried at elevated temperatures after washing to remove any water or solvent used in the washing step.

Once the catalytic carbon fibers have been synthesized as described above, the catalytic carbon fibers may be further processed by shaping the catalytic carbon fibers. For example, individual fibers of the catalytic carbon fibers may be drawn together and fixed to form catalytic carbon fiber bundles. The catalytic carbon fiber bundles may be utilized in a reactor to form a reaction zone within the reactor. Additional processing of the carbon fibers may include reducing the size of the carbon fibers to produce catalytic carbon fibers suitable for a fluidized bed, for example in a fluidized bed reactor, or may be pelletized or made suitable for use in a packed bed reactor.

Hydrocarbon streams in refineries and chemical plants often contain unwanted contaminants such as organically bound sulfur compounds, carboxylic acids, and hydrogen sulfide. Product specifications may require the reduction and/or removal of these contaminants during the refining process. Organically bound sulfur, such as mercaptan sulfur, may be present in some hydrocarbon streams in refineries or chemical plants. It may be desirable to reduce the mercaptan sulfur content of the hydrocarbon stream to produce a product stream with reduced mercaptan sulfur content. There are generally two options for treating mercaptan sulfur-containing streams. Mercaptan extraction may be utilized whereby the mercaptan sulfur is reacted with a caustic stream to produce organic sulfur compounds such as mercaptides. A portion of the mercaptides may be dissolved in the aqueous portion of the caustic stream, thereby removing the mercaptan sulfur from the hydrocarbon stream. In general, the solubility of the organosulfur compounds is a function of the hydrocarbon chain length, such that a relatively low molecular weight mercaptan may produce a more soluble product when reacted with a caustic stream, and a relatively high molecular weight mercaptan may produce a relatively less soluble product when reacted with a caustic stream. The organosulfur compounds may be further oxidized to disulfide oils by reacting the organosulfur compounds with oxygen in the presence of a catalyst. For some hydrocarbon streams containing heavier mercaptan sulfur-containing compounds, a mercaptan sweetener may be utilized to directly convert the mercaptan sulfur to disulfide oils by reacting the mercaptan sulfur with oxygen in the presence of a catalyst. Direct sweetening to disulfide oils may be preferred in some hydrocarbon streams where the organosulfur compounds produced are relatively insoluble in the aqueous portion of the caustic stream. Some operations may include extraction and sweetening in succession, whereby a mixed hydrocarbon stream containing relatively low molecular weight mercaptan sulfur and a portion of the relatively high molecular weight mercaptan sulfur is contacted with a caustic stream and then oxidized to produce a disulfide oil. Such operations may be carried out in separate units or as an integrated process in a single vessel. One example of a single vessel extraction/oxidation is the Mericat™ II process available from Merichem Company.

There are a wide variety of hydrocarbon streams that contain contaminants that may be removed. This application may only disclose embodiments relating to some specific hydrocarbon streams, but the disclosure herein may be readily applied to other hydrocarbon streams not specifically listed herein. The caustic treatment process may be suitable for treating any hydrocarbon feed, including, but not limited to, hydrocarbons such as alkanes, alkenes, alkynes, and aromatics. The hydrocarbons may include any chain length hydrocarbons, for example, from about _C3 to about _C30 , or greater, and may include any amount of branching. Some representative hydrocarbon feeds may include, but are not limited to, crude oil, propane, LPG, butane, light naphtha, isomerates, heavy naphtha, reformate, jet fuel, kerosene, diesel, hydrotreating distillates, heavy vacuum gas oil, light vacuum gas oil, gas oil, coker gas oil, alkylates, fuel oil, light cycle oil, and combinations thereof. Some non-limiting examples of hydrocarbon streams may include crude oil distillation unit streams such as light naphtha, heavy naphtha, jet fuel, and kerosene, fluid catalytic cracker or resid catalytic cracker gasoline, or natural gasoline from RCC, NGL fractionation, and gas condensates.

A method for extracting mercaptan sulfur may include contacting a hydrocarbon stream with a caustic stream containing hydroxides and reacting at least a portion of the mercaptan sulfur content of the hydrocarbon stream with the hydroxides in the caustic stream. The hydroxides may be any hydroxide capable of reacting with mercaptan sulfur. Some representative hydroxides may include Group I and Group II hydroxides, such as, for example, NaOH, KOH, RbOH, CsOH, Ca(OH) ₂ , and Mg(OH) ₂ . The hydroxides may be present in the aqueous solution at a concentration suitable for the particular application, typically from about 5 wt.% up to and including saturation.

The generalized reaction of hydroxides and mercaptan sulfurs is shown in Reaction 1, where mercaptan sulfur (RSH) reacts with hydroxide (XOH) to form the corresponding mercaptide (RSX) and water, where X is a Group I or Group II cation.

As discussed above, depending on the molecular weight of the mercaptan sulfur reacted with the hydroxide, some of the mercaptan sulfur produced may dissolve in the aqueous portion of the caustic stream. When the mercaptan sulfur is reacted with the caustic stream, a "spent caustic" or "rich caustic" solution may be produced that contains water, residual hydroxide, and soluble components. The spent caustic is regenerated to form a lean caustic with reduced mercaptide content for recycling back to reaction 1. One process of regeneration may include mixing oxygen or air with the spent caustic and contacting the resulting mixture with a catalyst to regenerate the caustic stream. A generalized process of regeneration is shown in reaction 2, where the mercaptide (RSX) reacts with water and oxygen in the presence of a catalyst to produce disulfide (RSSR), also called disulfide oil (DSO), caustic, and water.

As discussed above, one of the challenges in processing mercaptan sulfur is that there are problems with the extent of reaction, whereby the mercaptan sulfur concentration is not reduced to the level required for the resulting product stream to be on specification. In units utilizing an extractor section and an oxidation section, such as the UOP Merox™, the catalyst may be distributed in the caustic stream circulating through the extraction and oxidation sections of the unit. In sweetening units, the catalyst may be contained in a fixed bed in the reactor. The catalyst may be impregnated in charcoal or activated carbon, where the catalyst bed may be wetted with a caustic solution. In either case, the catalyst may not have sufficient catalytic activity and/or the residence time in the reactor may be too short to effectively oxidize the mercaptides. One representative use of the catalytic carbon fibers disclosed herein is to replace conventional oxygenation catalysts currently utilized in the oxidation of mercaptides to produce disulfide oils. As discussed in detail below, the catalytic carbon fibers exhibit high reactivity towards the oxidation of mercaptides and have desirable physical properties that make them well suited for use in mercaptide oxidation reactors.

There may be a wide variety of process conditions suitable for the oxidation of mercaptides, the exact conditions of which may vary depending on the hydrocarbon feed. For lighter hydrocarbons, the operating pressure may be controlled to be slightly above the bubble point to ensure liquid phase operation. For relatively heavier hydrocarbons, the pressure may be set to maintain dissolved air in the oxidation section. The operating temperature may also be selected based on the hydrocarbon feed, with general conditions ranging from about 20°C to about 100°C.

FIG. 1 illustrates one embodiment of a hydrocarbon desulfurization process 100 utilizing catalytic carbon fiber in mercaptide oxidation. In FIG. 1, a hydrocarbon feed 102 containing mercaptan sulfur compounds may be processed in a countercurrent multi-stage caustic processing section. Lean caustic 104 may be fed to a final stage 108 where it extracts mercaptans from the hydrocarbons that enter the final stage 108 after being initially processed in a first stage 106. Caustic may be removed from the final stage 108 as stream 110 and fed to the first stage 106 for contact with the hydrocarbon feed 102. A spent caustic stream 112 may be withdrawn from the first stage 106 and treated hydrocarbons 114 may be withdrawn from the final stage 108. The particular design of the caustic treatment section is not critical to the functionality of the catalytic carbon fibers of the present disclosure, but one design may include staged contactors operating in a counter-flow configuration as illustrated generally in FIG. 1, and another design uses a fiber film liquid-liquid contactor to assist in the mass transfer of mercaptans from the hydrocarbon feed 102 into the caustic treatment solution.

The spent caustic 112 withdrawn from the first stage 106 and the oxidizer 118 may be fed to the oxidation section 116. The oxidizer 118 may include any suitable oxidizer, including air, oxygen, hydrogen peroxide, or any other oxygen-containing gas or compound that releases oxygen. The oxidation section 116 may include catalytic carbon fiber as disclosed herein that can oxidize mercaptides present in the spent caustic 112 to form disulfide oil. The mercaptides, water, and oxygen in the spent caustic 112 react in the presence of the catalytic carbon fiber according to reaction 2 to produce disulfide oil, regenerated caustic, and water. The regenerated caustic may be discharged as a regenerated caustic stream 118, and the disulfide oil may be discharged as a disulfide stream 124. An off-gas steam 126 containing residual gaseous hydrocarbons, air, oxygen, or other gases is withdrawn from the oxidation section 116 and may be sent to downstream units for further processing or to a flare if desired.

Because conditions within the oxidation section 116 may be conducive to forming explosive mixtures with the combination of hydrocarbons and oxidizer, it may be desirable to operate the oxidation section 116 so that the gas present therein is below the lower explosive limit (LEL) or above the upper explosive limit (UEL). A gas stream 120 may be introduced into the oxidation section 116 in some cases so that LEL/UEL conditions are maintained. The gas stream 120 may include a fuel gas, an inert gas, or any other suitable gas for controlling the LEL/UEL. Another alternative may include a solvent stream 122 into the oxidation section 116. The solvent stream 122 may be from any source, but preferably contains little or no disulfide oil. The solvent stream 122 may be mixed with the spent caustic stream 112 before entering the oxidation section 116, or it may be injected as a separate stream into the bottom of the oxidation section 116. The solvent can be any light hydrocarbon or mixture of light hydrocarbons, such as naphtha and kerosene, that aids in the separation of the disulfide oil from the caustic solution after oxidation of the mercaptans. The disulfide oil may have a higher solubility in DSO compared to the aqueous portion of the spent caustic 112, and these solubility differences provide the driving force for extraction in the DSO. In embodiments where a solvent is utilized, the solvent may be drawn off along with the disulfide oil in the disulfide stream 124.

In some embodiments, the regenerated caustic stream 118 may be further purified in a solvent wash section 128, whereby a solvent stream 130 contacts the regenerated caustic stream 118 to further remove DSO from the regenerated caustic stream 118. A spent caustic stream 132 may be withdrawn from the solvent wash section 128 and additional fresh caustic from a fresh caustic stream 134 may be added to form the diluted caustic 104.

2 illustrates one embodiment of a hydrocarbon desulfurization vessel 200 including catalytic carbon fibers as described herein. As illustrated, the hydrocarbon desulfurization vessel 200 includes a caustic treatment section 202 including a fiber bundle 204 and an oxidation section 206 including catalytic carbon fibers 208. A conduit 210 may include the caustic treatment section 202 including the fiber bundle 204 that may physically separate the caustic treatment section 202 from the oxidation section 206 and provide a flow path for fluid to pass through. The oxidation section 206 including the catalytic carbon fibers 208 may be disposed in the annular space formed between the conduit 210 and the wall of the vessel 200.

The hydrocarbon feed 212 containing the mercaptan sulfur compounds to be treated may be mixed with the oxidant 214 and introduced into the conduit 210. In some embodiments, a sparger 218 may be utilized to distribute the oxidant 214 throughout the hydrocarbon feed 21. The oxidant 214 may include any suitable oxidant, including air, oxygen, hydrogen peroxide, or any other oxygen-containing gas or compound that releases oxygen. Generally, the amount of oxidant 214 introduced should be sufficient to oxidize all of the mercaptan sulfur compounds present in the hydrocarbon feed 212. Once the hydrocarbon/oxidant feed is introduced into the conduit 210, it flows through the conduit 210 and contacts the fiber bundle 204. A caustic stream 220 may be introduced into the conduit 210 such that the hydrocarbon feed/oxidant feed is mixed with the caustic stream 220 before contacting the fiber bundle 204. In some embodiments, it may be desirable to disperse the caustic from the caustic stream 220 to enhance contact between the hydrocarbon phase from the hydrocarbon feed 212 and the aqueous phase from the caustic stream 220. In such embodiments, the line 222 may be connected to a distributor 224 disposed above the fiber bundle 204, such that the caustic stream 220 connects to the distributor 224 via the line 222 and the hydrocarbon/oxidant feed may be mixed with the caustic from the caustic stream 220 above the fiber bundle 204.

In either embodiment, caustic from the hydrocarbon/oxidant feed and caustic stream 220 may contact the fiber bundle 204, which causes the aqueous caustic to wet the individual fibers of the fiber bundle 204. The aqueous caustic solution forms a film on the fibers 204, which is dragged downstream through conduit 210 by the hydrocarbon passing through the same conduit. Both liquids may be discharged to a separation zone 226 of the vessel 200. The volume of the hydrocarbon will be greater because the aqueous caustic passes through the fiber bundle at a lower volumetric flow rate than the hydrocarbon. During the relative movement of the hydrocarbon with respect to the aqueous caustic film on the fibers, new interfaces between the hydrocarbon and the aqueous caustic solution are continually formed, and as a result new aqueous caustic solution comes into contact with this surface and is allowed to react with the mercaptan sulfur in the hydrocarbon or other impurities such as phenols, naphthenic acids and other organic acids. The mercaptan sulfur present in the hydrocarbon feed may react with the caustic to produce mercaptides as shown in reaction 1.

In the separation zone 226, the aqueous caustic solution and the hydrocarbons may be collected in the lower portion of the vessel 200 and separated into a hydrocarbon phase 228 and a caustic phase 230. The interface 232 in the vessel 200 may be maintained at a level above the bottom of the downstream end of the fiber bundle 204 so that the aqueous caustic film may be collected directly at the bottom of the vessel 200 without being dispersed in the hydrocarbon phase 228. Most of the phenolate or naphthenic acid impurities that may cause plugging of the packed bed are thus removed from the hydrocarbons in the caustic phase. This not only increases the oxidation efficiency but also reduces maintenance costs. However, some impurities may remain in the hydrocarbons, which need to be further treated with the caustic solution in the oxidation section 206. The caustic phase 230 may be withdrawn from the vessel 200 via a pump 234 and returned to the conduit 210 via the caustic stream 220. The height of the interface 232 within the vessel 200 may be controlled by a level control system 236, including a level sensor, a level controller, and a purge valve, and may be configured to maintain the interface 232 at a level above the downstream end of the fiber bundle 204.

From the separation zone 226, the hydrocarbon phase 228 may flow upward into the oxidation section 206, whereby the hydrocarbon phase 228 contacts the catalytic carbon fibers 208. Additional caustic may be introduced into the oxidation section 206 via line 238, if necessary. A distribution grid may be present in the oxidation section 206 that distributes the caustic from line 238 into the oxidation section 206. In the oxidation section 206, the mercaptides, water, and oxygen may react according to reaction 2 in the presence of the catalytic carbon fibers to produce disulfide oil, regenerated caustic, and water, which may flow upward through the oxidation section 206. The additional caustic and the hydrocarbon may contact and flow simultaneously through the oxidation section 206. At the top of the catalytic carbon fibers, the additional caustic may be separated from the hydrocarbons by a liquid separation device, such as a chimney-type tray, in the separation section 240. Although a chimney-type tray is shown, there are many alternative types of liquid separators that can be used, such as, for example, overflow weirs. Additional hydroxides may be collected in separation section 240 and discharged as stream 242 that is reintroduced to oxidation section 206. Make-up caustic 244 may be added intermittently and a caustic purge may be utilized as needed. Hydrocarbon product 246 may be withdrawn from the top of separation section 240. Off-gas that builds up in vessel 200 may be discharged through line 248 and processed in downstream units.

3 illustrates another embodiment of a hydrocarbon desulfurization vessel 300 including catalytic carbon fibers as described herein. FIG. 3 illustrates a process carried out in a single vessel in which a hydrocarbon feed 302, an oxidant 304, a caustic stream 306, and optionally a solvent stream 308 are introduced into an oxidation section 310. The oxidant 304 may include any suitable oxidant, including air, oxygen, hydrogen peroxide, or any other oxygen-containing gas or compound that releases oxygen. Each of the streams may be introduced into the vessel 300 through a distributor 312 that may distribute the feed into the oxidation section 310. The oxidation section 310 includes catalytic carbon fibers 314 positioned to receive the feed from the distributor 312.

In the oxidation section 310, the hydrocarbons from the hydrocarbon feed 302 and the caustic from the caustic stream 306 may contact the catalytic carbon fibers 314, which causes the aqueous caustic to wet the individual fibers of the catalytic carbon fibers 314. The aqueous caustic solution forms a film on the catalytic carbon fibers 314, which is dragged downstream through the oxidation zone 310 by the passage of the hydrocarbons through the vessel 300. During the relative movement of the hydrocarbons with respect to the aqueous caustic film on the fibers, new interfaces between the hydrocarbons and the aqueous caustic solution are continually formed, such that new aqueous caustic solution comes into contact with this surface and is allowed to react with the mercaptan sulfur in the hydrocarbons or other impurities such as phenols, naphthenic acids and other organic acids. The mercaptan sulfur present in the hydrocarbon feed may react with the caustic to produce mercaptides as shown in reaction 1. The generated mercaptides can further react with oxygen provided by oxidant 304 in the presence of catalytic carbon fiber 314 to generate disulfide oil, regenerated caustic, and water, as shown in reaction 2.

The oxidation of mercaptides to disulfide oils occurring in the oxidation section 310 may result in a mixture consisting of continuous phase caustic, discontinuous phase organic (disulfide oil and solvent, if present) droplets dispersed in the caustic phase, and gas (nitrogen and unreacted oxygen from air). The mixture of products, unreacted reactants, and inert species may exit the oxidation section 310, contact the fiber bundle 318, and flow into the separation section 316. The fiber bundle may promote phase separation as previously described. In the separation section 316, the aqueous caustic and hydrocarbons may be collected in the lower portion of the separation section 316 and separated into a hydrocarbon phase 320, a caustic phase 322, and a gas phase 324. Gas from the oxidizer 304 leaves the liquid stream at the outlet of the fiber bundle 318 and exits through the mist eliminator 326 as off-gas 328. The two immiscible liquids flow downward along the fiber bundle 318 as a single stream, while the organic hydrocarbon droplets coalesce to form a hydrocarbon phase 320, while the aqueous caustic adheres to the fibers and flows further down to form a caustic phase 322.

A hydrocarbon phase 320, including the hydrocarbons from the hydrocarbon feed 302 and the generated disulfide oil and solvent, if present, may be withdrawn as stream 330. A caustic phase 322 includes the remaining disulfide oil, which may be further reduced before the caustic is recycled in the vessel 300. The caustic phase 322 may be withdrawn as stream 332, which may be mixed with a fresh solvent stream 334 before contacting the fiber bundle 338 and flowing into a separation section 336. In the separation section 336, the aqueous caustic from the caustic phase 322 and the solvent from the solvent stream 334 may be collected in the lower portion of the separation section 336 and separated into a solvent phase 340 and a caustic phase 342. The solvent phase 340 may include most of any residual disulfide oil present in the caustic phase 322 after flowing through the fiber bundle 338. The solvent phase 340 may be withdrawn as solvent stream 308 to the vessel 300 and recycled. The caustic phase 342 may be withdrawn as stream 344 and recycled.

4 illustrates a stand-alone caustic regeneration unit 400 including catalytic carbon fibers 402 disposed in an oxidation zone 404. A spent caustic stream 406 may be mixed with an oxidizer 408 and introduced into the caustic regeneration unit 400 through a distributor 410. The spent caustic stream may be from any unit, including those previously described herein, that includes spent caustic and mercaptides. The oxidizer 408 may include any suitable oxidizer, including air, oxygen, hydrogen peroxide, or any other oxygen-containing gas or compound that releases oxygen. The mixture of the oxidizer 408 and the spent caustic stream 406 may contact the catalytic carbon fibers, which causes the aqueous caustic to wet the individual fibers of the catalytic carbon fibers 402. The mercaptides present in the caustic stream 406 further react with oxygen provided by the oxidant 408 in the presence of the catalytic carbon fiber 402 as shown in reaction 2 to produce disulfide oil, regenerated caustic, and water, which flow upward along the catalytic carbon fiber 402. The resulting disulfide oil, regenerated caustic, or both, may be withdrawn from the regeneration unit 400 as stream 412. Although illustrated in FIG. 4 as one stream, stream 412 may be two or more streams, such as in previous figures, where the aqueous and oily phases are withdrawn separately. Off-gas 414 may also be withdrawn from the caustic regeneration unit 400.

Figure 5a illustrates a stand-alone caustic regeneration unit 500 including catalytic fibers 502 disposed in an oxidation zone 504. A rich caustic stream 506, including mercaptides and/or sulfides, enters the top of the vessel. An oxidizer 508 enters above a distributor tray 510. The oxidizer 508 may include any suitable oxidizer, including air, oxygen, hydrogen peroxide, or any other oxygen-containing gas or compound that releases oxygen. One example of a distributor tray is shown in Figure 5b, but other variations may apply as well. At the distributor tray 510, a solvent stream 520 may also be introduced above the distributor tray 510. The distributor tray 510 distributes these phases to the catalytic fibers 502. In some embodiments, a riser pipe 516 may be disposed above the distributor tray 510. A mixture of at least the oxidant 508 and the rich caustic stream 506 may contact the catalytic carbon fibers 502, which causes the aqueous caustic to wet the individual fibers of the catalytic carbon fibers 502. The mercaptides present in the caustic stream 506 may further react with oxygen provided by the oxidant 508 in the presence of the catalytic carbon fibers 502 as shown in reaction 2 to produce disulfide oil, regenerated caustic, and water, which flow downwardly along the catalytic carbon fibers 502. The resulting disulfide oil, regenerated caustic, or both may be withdrawn from the regeneration unit 500 as stream 512. Although illustrated in FIG. 5 as one stream, stream 512 may be two or more streams, such as in previous figures, where the aqueous and oily phases are withdrawn separately. Off-gas 514 may also be withdrawn from the caustic regeneration unit 500. FIG. 5b shows a top view of the distributor tray 510 with riser pipes 516 and holes 518 that allow fluid to flow through the distributor tray 510.

Accordingly, the present disclosure provides methods, systems, and devices that may relate to fluid-fluid contact. The methods, systems, and devices may include any of the various features disclosed herein, including one or more of the following statements:

Statement 1. A method for producing catalytic carbon fiber, comprising: oxidizing virgin carbon fiber to produce oxidized carbon fiber; reacting the oxidized carbon fiber with a polyamine compound to produce an amine-modified carbon fiber; and reacting the amine-modified carbon fiber with an organometallic macrocycle to produce a catalytic carbon fiber.

Statement 2. The method of statement 1, wherein the oxidizing step includes contacting the carbon fiber with an acid selected from hydrochloric acid, nitric acid, phosphoric acid, sulfuric acid, boric acid, hydrofluoric acid, hydrobromic acid, perchloric acid, hydroiodic acid, fluoroantimonic acid, carborane acid, fluoroboric acid, fluorosulfuric acid, hydrogen fluoride, triflic acid, perchloric acid, acetic acid, formic acid, citric acid, oxalic acid, tartaric acid, and combinations thereof.

Statement 3. The method of statement 2, wherein the oxidation step is carried out at a temperature in the range of about 0°C to about 150°C.

Statement 4. The method of any of statements 1-3, wherein the polyamine compound comprises a primary or secondary polyamine having a carbon length of C2-C20.

Statement 5. The method of any of statements 1-4, wherein the polyamine compound comprises at least one polyamine compound selected from ethylenediamine, propane-1,3-diamine, butane-1,4-diamine, pentane-1,5-diamine, hexamethylenediamine, diethylenetriamine, benzene-1,3,5-triamine, and combinations thereof.

Statement 6. The method of any of statements 1-5, wherein the step of reacting the oxidized carbon fiber with the polyamine compound is carried out at a temperature in the range of about 0°C to 250°C.

Statement 7. The method of any of statements 1-6, wherein the step of reacting the amine-modified carbon fiber with the organometallic macrocycle is carried out at a temperature in the range of about 0° C. to 150° C.

Statement 8. The method of any of statements 1-7, wherein the organometallic macrocycle comprises an unsubstituted metallophthalocyanine, a substituted metallophthalocyanine, or a combination thereof.

Statement 9. The method of statement 8, wherein the substituted metal phthalocyanine is substituted with at least one of a halogen group, a hydroxyl group, an amine group, an alkyl group, an aryl group, a thiol group, an alkoxy group, a nitrosyl group, or a combination thereof.

Statement 10. The method of statement 8, wherein the unsubstituted or substituted metal phthalocyanine comprises a metal selected from vanadium (V), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), and combinations thereof.

Statement 11. A method of producing catalytic carbon fiber, comprising: oxidizing virgin carbon fiber to produce oxidized carbon fiber; reacting an organometallic macrocycle with a polyamine compound to produce an amine-modified organometallic macrocycle; and reacting the oxidized carbon fiber with the amine-modified organometallic macrocycle to produce catalytic carbon fiber.

Statement 12. The method of statement 11, wherein the oxidizing step includes contacting the carbon fiber with an acid selected from hydrochloric acid, nitric acid, phosphoric acid, sulfuric acid, boric acid, hydrofluoric acid, hydrobromic acid, perchloric acid, hydroiodic acid, fluoroantimonic acid, carborane acid, fluoroboric acid, fluorosulfuric acid, hydrogen fluoride, triflic acid, perchloric acid, acetic acid, formic acid, citric acid, oxalic acid, tartaric acid, and combinations thereof.

Statement 13. The method of any of statements 11-12, wherein the polyamine compound comprises at least one polyamine compound selected from ethylenediamine, propane-1,3-diamine, butane-1,4-diamine, pentane-1,5-diamine, hexamethylenediamine, diethylenetriamine, benzene-1,3,5-triamine, and combinations thereof.

Statement 14. The method of any of statements 11-13, wherein the organometallic macrocycle comprises an unsubstituted metallophthalocyanine, a substituted metallophthalocyanine, or a combination thereof.

Statement 15. The method of statement 14, wherein the substituted metal phthalocyanine is substituted with at least one of a halogen group, a hydroxyl group, an amine group, an alkyl group, an aryl group, a thiol group, an alkoxy group, a nitrosyl group, or a combination thereof.

Statement 16. The method of statements 14-15, wherein the unsubstituted or substituted metal phthalocyanine comprises a metal selected from vanadium (V), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), and combinations thereof.

Statement 17. A catalyzed carbon fiber comprising: a carbon fiber; an amine compound covalently bonded to the carbon fiber; and an organometallic macrocycle covalently bonded to the amine compound.

Statement 18. The catalyzed carbon fiber of statement 17, wherein the amine compound comprises at least one polyamine compound selected from ethylenediamine, propane-1,3-diamine, butane-1,4-diamine, pentane-1,5-diamine, hexamethylenediamine, diethylenetriamine, benzene-1,3,5-triamine, and combinations thereof.

Statement 19. A catalyzed carbon fiber according to any of statements 17 to 18, wherein the amine compound comprises ethylenediamine.

Statement 20. The catalyzed carbon fiber of statement 19, wherein the organometallic macrocycle comprises a metal phthalocyanine.

Statement 21. A fiber bundle contactor comprising: a flow path defined by a conduit; a catalytic carbon fiber bundle disposed in the conduit; and an inlet for permitting fluid to flow through the flow path.

Statement 22. The fiber bundle contactor of Statement 21, wherein the catalytic carbon fiber bundle comprises carbon fiber, an amine compound covalently bonded to the carbon fiber, and an organometallic macrocycle covalently bonded to the amine compound.

Statement 23. The fiber bundle contactor of any one of claims 21 to 22, wherein the amine compound comprises a primary or secondary polyamine having a carbon length of C2 to C20.

Statement 24. The fiber bundle contactor of any of statements 21-23, wherein the amine compound comprises at least one polyamine compound selected from ethylenediamine, propane-1,3-diamine, butane-1,4-diamine, pentane-1,5-diamine, hexamethylenediamine, diethylenetriamine, benzene-1,3,5-triamine, and combinations thereof.

Statement 25. The fiber bundle contactor of any of statements 21-24, wherein the organometallic macrocycle comprises an unsubstituted phthalocyanine, a substituted phthalocyanine, or a combination thereof.

Statement 26. The fiber bundle contactor of any of statements 21-25, wherein the substituted metal phthalocyanine is substituted with at least one of a halogen group, a hydroxyl group, an amine group, an alkyl group, an aryl group, a thiol group, an alkoxy group, a nitrosyl group, or a combination thereof.

Statement 27. The fiber bundle contactor of any of statements 21-26, wherein the unsubstituted or substituted phthalocyanine comprises a metal selected from vanadium (V), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), and combinations thereof.

Statement 28. The fiber bundle contactor of any of statements 21-27, wherein the catalyzed carbon fiber bundle comprises carbon fiber and ethylenediamine and phthalocyanine covalently bonded to the carbon fiber.

Statement 29. The fiber bundle contactor of any of statements 21-28, wherein the catalytic carbon fiber has a second order mercaptan oxidation rate constant of at least 5.45 x 10^-4 (1/M x min) at 38°C.

Statement 30. A method comprising: introducing a hydrocarbon containing mercaptan sulfur, an aqueous caustic solution, and an oxidizing agent into a vessel; reacting at least a portion of the mercaptan sulfur and the aqueous caustic solution to produce a mercaptide; and reacting the mercaptide and the oxidizing agent in the presence of catalytic carbon fiber bundles to produce a disulfide oil.

Statement 31. The method of statement 30, wherein the catalyzed carbon fiber bundle comprises carbon fibers, an amine compound covalently bonded to the carbon fibers, and an organometallic macrocycle covalently bonded to the amine compound.

Statement 32. The method of any of statements 30-31, wherein the amine compound comprises a primary or secondary polyamine having a carbon length of C2 to C20.

Statement 33. The method of statements 30-32, wherein the amine compound comprises at least one polyamine compound selected from ethylenediamine, propane-1,3-diamine, butane-1,4-diamine, pentane-1,5-diamine, hexamethylenediamine, diethylenetriamine, benzene-1,3,5-triamine, and combinations thereof.

Statement 34. The method of statements 30-33, wherein the organometallic macrocycle comprises an unsubstituted phthalocyanine, a substituted phthalocyanine, or a combination thereof.

Statement 35. The method of statements 30-34, wherein the substituted metal phthalocyanine is substituted with at least one of a halogen group, a hydroxyl group, an amine group, an alkyl group, an aryl group, a thiol group, an alkoxy group, a nitrosyl group, or a combination thereof.

Statement 36. The method of statements 30-35, wherein the unsubstituted or substituted phthalocyanine comprises a metal selected from vanadium (V), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), and combinations thereof.

Statement 37. The method of statements 30-36, further comprising contacting the hydrocarbon containing mercaptan sulfur and the aqueous caustic solution on the fiber bundle, wherein reacting a portion of the mercaptan sulfur and the aqueous caustic solution to produce mercaptides occurs within the fiber bundle.

Statement 38. The method of statements 30-37, wherein reacting the mercaptide and the oxidant in the presence of the catalytic carbon fiber bundle further produces a regenerated caustic stream, which is recycled to the vessel.

Statement 39. A method comprising: introducing an aqueous solution containing a mercaptide and an oxidizing agent into a vessel; and reacting the mercaptide and the oxidizing agent in the presence of catalytic carbon fiber bundles to produce an aqueous caustic solution.

Statement 40. The method of statement 40, wherein the catalyzed carbon fiber bundle comprises carbon fiber, a primary or secondary polyamine having a carbon length of C2 to C20 covalently bonded to the carbon fiber, and an unsubstituted phthalocyanine or a substituted phthalocyanine covalently bonded to the amine compound.

Statement 41. A method of producing a catalytic carbon fiber, comprising: providing carbon fiber and an aminated macrocycle; mixing the carbon fiber and the aminated macrocycle with a solvent; and reacting the carbon fiber and the aminated macrocycle to form an amide bond between the carbon fiber and the aminated macrocycle, thereby forming the catalytic carbon fiber.

Statement 42. The method of statement 41, wherein the aminated macrocycle comprises an organometallic macrocycle and an amine group grafted to the organometallic macrocycle.

Statement 43. The method of statement 42, wherein the organometallic macrocycle comprises an unsubstituted metallophthalocyanine, a substituted metallophthalocyanine, or a combination thereof.

Statement 44. The method of statement 43, wherein the substituted metal phthalocyanine is substituted with at least one of a halogen group, a hydroxyl group, an alkyl group, an aryl group, a thiol group, an alkoxy group, a nitrosyl group, a sulfonic acid group, or a combination thereof.

Statement 45. The method of statements 43-44, wherein the unsubstituted or substituted metal phthalocyanine comprises a metal selected from vanadium (V), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), and combinations thereof.

Statement 46. The method of claim 42, wherein the amine group comprises an amine having a carbon length of C2 to C20.

Statement 47. The method of any of statements 41-46, wherein the solvent comprises at least one solvent selected from the group consisting of water, pyridine, DMSO, DMF, THF, ethanol, acetonitrile, chloroform, ethylene glycol, methanol, benzene, and combinations thereof.

Statement 48. The method of statement 42, wherein the amine group comprises a reaction product of at least one amine compound selected from ethylenediamine, propane-1,3-diamine, butane-1,4-diamine, pentane-1,5-diamine, hexamethylenediamine, diethylenetriamine, benzene-1,3,5-triamine, and combinations thereof.

Statement 49. The method of any of statements 41-48, wherein the aminated macrocycle comprises at least one of monoaminocobalt phthalocyanine, diaminocobalt phthalocyanine, triaminocobalt phthalocyanine, tetraaminocobalt phthalocyanine, and combinations thereof.

Statement 50. The method of any of statements 41-49, wherein the reacting is carried out at a temperature in the range of about 100°C to about 200°C.

Statement 51. A method of producing a catalytic carbon fiber, comprising: providing a carbon fiber; reacting the carbon fiber with a chlorinating agent to produce a carbon fiber containing an acyl chloride; and reacting the carbon fiber containing an acyl chloride with an aminated macrocycle to form an amide bond between the carbon fiber containing an acyl chloride and the aminated macrocycle, thereby forming the catalytic carbon fiber.

Statement 52. The method of statement 51, wherein the chlorinating agent comprises a chlorinating agent selected from the group consisting of thionyl chloride, phosphorus trichloride, terephthaloyl chloride, and combinations thereof.

Statement 53. The method of any of statements 51-52, wherein the aminated macrocycle comprises an organometallic macrocycle and an amine group grafted to the organometallic macrocycle.

Statement 54. The method of statement 53, wherein the organometallic macrocycle comprises an unsubstituted metallophthalocyanine, a substituted metallophthalocyanine, or a combination thereof.

Statement 55. The method of statements 53-54, wherein the substituted metal phthalocyanine is substituted with at least one of a halogen group, a hydroxyl group, an alkyl group, an aryl group, a thiol group, an alkoxy group, a nitrosyl group, a sulfonic acid group, or a combination thereof.

Statement 56. The method of statements 53-55, wherein the unsubstituted or substituted metal phthalocyanine comprises a metal selected from vanadium (V), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), and combinations thereof.

Statement 57. The method of any of statements 51-56, further comprising removing thionyl chloride from the acyl chloride-containing carbon fiber and dispersing the acyl chloride-containing carbon fiber in a solvent prior to the step of reacting the aminated macrocycle with the acyl chloride-containing carbon fiber.

Statement 58. The method of any of statements 51-57, wherein the step of reacting the aminated macrocycle with the carbon fiber containing the acyl chloride comprises reacting in the presence of pyridine.

Statement 59. A method of producing a catalytic carbon fiber, comprising: providing a carbon fiber; reacting the carbon fiber with a coupling agent to produce a functionalized carbon fiber; and reacting the functionalized carbon fiber with an aminated macrocycle to form an amide bond between the carbon fiber and the aminated macrocycle, thereby forming the catalytic carbon fiber.

Statement 60. The method of statement 59, wherein the coupling agent comprises a carbodiimide, a benzotriazole, or a combination thereof.

Statement 61. A method of producing a catalyzed carbon fiber, comprising: providing a carbon fiber; providing an enzyme capable of catalyzing amide bond formation; and reacting the carbon fiber with an aminated macrocycle in the presence of the enzyme to form a bond between the carbon fiber and the aminated macrocycle, thereby forming the catalyzed carbon fiber.

Statement 62. The method of statement 61, wherein the enzyme comprises an enzyme selected from the group consisting of a protease, a subtilisin, an acylases, an amidases, a lipases, and combinations thereof.

EXAMPLES To facilitate a better understanding of the present disclosure, the following illustrative examples of some of the embodiments are given. Such examples should in no way be read as limiting or defining the scope of the present disclosure.

Example 1
In this example, the mercaptan oxidation potential of virgin carbon fiber was evaluated. Kerosene containing 300 ppm of mercaptan sulfur was prepared. A 3 gram sample of virgin carbon fiber and 150 mL of mercaptan sulfur-containing kerosene were vigorously mixed in a shaker bath at 300 RPM and 38°C. The kerosene samples were drawn for 30 minutes and the mercaptan concentration in each sample was determined by titration. The second order mercaptan oxidation rate constant was calculated to be 0.22 x 10 ^-4 (l/M x min). It was observed that virgin carbon fiber showed little catalytic activity towards mercaptan oxidation.

Example 2
In this example, carbon fibers modified with cobalt phthalocyanine were prepared and the mercaptan oxidation of the modified carbon fibers was evaluated. A dimethyl sulfoxide (DMSO) solution was prepared by mixing 4 g of 4-aminopyridine with 200 mL of DMSO. Then, 4 grams of virgin carbon fibers were weighed and added to the DMSO solution, and the mixture was kept at 80°C for 22 hours. The carbon fibers were washed with isopropyl alcohol, followed by distilled water, and dried at 60°C in air. After drying, the carbon fibers were mixed in an aqueous solution containing 1% dibrominated cobalt phthalocyanine at room temperature for 15 hours. The cobalt phthalocyanine modified carbon fibers were then washed with distilled water and dried at 60°C.

Kerosene containing 300 ppm of mercaptan sulfur was prepared. Three grams of the cobalt phthalocyanine modified carbon fiber sample from this example and 150 mL of mercaptan sulfur-containing kerosene were vigorously mixed in a shaker bath at 300 RPM and 38° C. Kerosene samples were drawn off for 30 minutes and the mercaptan concentration in each sample was determined by titration. The second order mercaptan oxidation rate constant was calculated to be 3.5×10 ⁻⁴ (l/M×min).

Example 3
In this example, cobalt phthalocyanine modified carbon fiber was prepared by the method described above, and the mercaptan oxidation of the modified carbon fiber was evaluated. 10 g of virgin carbon fiber was weighed and added to 175 mL of 70% nitric acid at 80° C. for 5 hours. After the nitric acid treatment, the carbon fiber was washed with distilled water and then mixed with ethylenediamine at 105° C. for 3 hours to obtain amine-modified carbon fiber. The amine-modified carbon fiber was then added to a pyridine solution containing 1.3 wt. % dibrominated cobalt phthalocyanine at room temperature for 22 hours.

Kerosene containing 300 ppm of mercaptan sulfur was prepared. Three grams of the cobalt phthalocyanine modified carbon fiber sample from this example and 150 mL of mercaptan sulfur containing kerosene were vigorously mixed in a shaker bath at 300 RPM and 38°C. The kerosene samples were drawn off for 30 minutes and the mercaptan concentration in each sample was determined by titration. The second order mercaptan oxidation rate constant was calculated to be 5.45 x 10 ^-4 (l/M x min). It was observed that the mercaptan oxidation activity was increased by 56% using the amine method to prepare the cobalt phthalocyanine modified carbon fiber.

The present disclosure is therefore well adapted to achieve the objects and advantages mentioned, as well as the essentials thereof. The specific embodiments disclosed above are merely illustrative, as the disclosure may be modified and implemented in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Although individual embodiments are discussed, the present disclosure covers all combinations of those embodiments. Moreover, no limitations are intended to the details of construction or design shown herein, other than as set forth in the following claims. Furthermore, the terms in the claims have their plain and ordinary meaning unless expressly and clearly defined by the patent owner. Thus, it is apparent that the specific illustrative embodiments disclosed above may be altered or modified, and all such variations are deemed to be within the scope or spirit of the present disclosure. In the event of any dispute in the use of words or terms in this specification and in one or more patents or other documents which may be incorporated herein by reference, the definition consistent with this specification should be adopted.

Claims (16)

oxidizing virgin carbon fibers to produce oxidized carbon fibers;
reacting the oxidized carbon fiber with a polyamine compound to produce an amine -modified carbon fiber and form a covalent bond between the oxidized carbon fiber and the polyamine compound ; and
reacting the amine-modified carbon fiber with a metal phthalocyanine to produce a catalytic carbon fiber , forming a covalent bond between the amine-modified carbon fiber and the metal phthalocyanine . The method of claim 1, wherein the step of oxidizing comprises contacting the virgin carbon fiber with an acid selected from hydrochloric acid, nitric acid, phosphoric acid, sulfuric acid, boric acid, hydrofluoric acid, hydrobromic acid, perchloric acid, hydroiodic acid, fluoroantimonic acid, carborane acid, fluoroboric acid, fluorosulfuric acid, hydrogen fluoride, triflic acid, perchloric acid, acetic acid, formic acid, citric acid, oxalic acid, tartaric acid, and combinations thereof. The method of claim 1, wherein the polyamine compound comprises a primary or secondary polyamine having a carbon length of C2 to C20. The method of claim 1, wherein the polyamine compound comprises at least one polyamine compound selected from ethylenediamine, propane-1,3-diamine, butane-1,4-diamine, pentane-1,5-diamine, hexamethylenediamine, diethylenetriamine, benzene-1,3,5-triamine, and combinations thereof. 2. The method of claim 1, wherein the metal phthalocyanine comprises an unsubstituted metal phthalocyanine, a substituted metal phthalocyanine, or a combination thereof, wherein the substituted metal phthalocyanine is substituted with at least one of a halogen group, a hydroxyl group, an amine group, an alkyl group, an aryl group, a thiol group, an alkoxy group, a nitrosyl group, or a combination thereof, and the unsubstituted metal phthalocyanine or the substituted metal phthalocyanine comprises a metal selected from vanadium (V), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), and combinations thereof. providing a carbon fiber and an unsubstituted metal phthalocyanine and/or a substituted metal phthalocyanine , wherein the unsubstituted metal phthalocyanine and the substituted metal phthalocyanine have an amine covalently bonded thereto having a carbon length of C2 to C20, the substituted metal phthalocyanine being substituted with at least one of a halogen group, a hydroxyl group, an alkyl group, an aryl group, a thiol group, an alkoxy group, a nitrosyl group, a sulfonic acid group, or a combination thereof, and the unsubstituted metal phthalocyanine or the substituted metal phthalocyanine comprises a metal selected from vanadium (V), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), and combinations thereof;
13. A method of producing catalytic carbon fibers, comprising: combining said carbon fibers and said unsubstituted metal phthalocyanine and/or said substituted metal phthalocyanine with a solvent; and reacting said carbon fibers and said unsubstituted metal phthalocyanine and/or said substituted metal phthalocyanine to form a covalent bond between said carbon fibers and said unsubstituted metal phthalocyanine and/or said substituted metal phthalocyanine , thereby forming catalytic carbon fibers. 7. The method of claim 6 , wherein the solvent comprises at least one solvent selected from the group consisting of water, pyridine, DMSO, DMF, THF, ethanol, acetonitrile, chloroform, ethylene glycol, methanol, benzene, and combinations thereof. 7. The method of claim 6, wherein the amine comprises at least one amine compound selected from ethylenediamine, propane-1,3-diamine, butane-1,4-diamine, pentane-1,5-diamine, hexamethylenediamine, diethylenetriamine, benzene-1,3,5-triamine, and combinations thereof, and the unsubstituted and/or substituted metal phthalocyanine comprises at least one of monoaminocobalt phthalocyanine, diaminocobalt phthalocyanine, triaminocobalt phthalocyanine, tetraaminocobalt phthalocyanine, and combinations thereof. A flow path defined by a conduit;
a catalytic carbon fiber bundle disposed in the conduit, the catalytic carbon fiber bundle comprising carbon fibers, an amine compound covalently bonded to the carbon fibers, and an unsubstituted metal phthalocyanine, a substituted metal phthalocyanine, or combinations thereof, covalently bonded to the amine compound, wherein the substituted metal phthalocyanine is substituted with at least one of a halogen group, a hydroxyl group, an amine group, an alkyl group, an aryl group, a thiol group, an alkoxy group, a nitrosyl group, or combinations thereof, and the unsubstituted metal phthalocyanine or the substituted metal phthalocyanine comprises a metal selected from vanadium (V), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), and combinations thereof ; and a fiber bundle contactor comprising an inlet to allow fluid flow into the flow path. 10. The fiber bundle contactor of claim 9 , wherein the amine compound comprises a primary or secondary polyamine having a carbon length of C2 to C20. 10. The fiber bundle contactor of claim 9, wherein the amine compound comprises at least one polyamine compound selected from ethylene diamine, propane-1,3-diamine, butane-1,4-diamine, pentane-1,5-diamine, hexamethylene diamine, diethylene triamine, benzene- 1,3,5 -triamine, and combinations thereof. 10. The fiber bundle contactor of claim 9 , wherein said catalyzed carbon fiber bundle comprises carbon fibers and ethylenediamine and phthalocyanine covalently bonded to said carbon fibers. introducing into a vessel a mercaptan sulfur containing hydrocarbon, an aqueous caustic solution, and an oxidizer;
reacting at least a portion of the mercaptan sulfur and the aqueous caustic solution to produce a mercaptide; and reacting the mercaptide and the oxidant in the presence of a catalytic carbon fiber bundle to produce a disulfide oil, wherein the catalytic carbon fiber bundle comprises carbon fibers, an amine compound covalently bonded to the carbon fibers, and an unsubstituted metal phthalocyanine, a substituted metal phthalocyanine, or combinations thereof, covalently bonded to the amine compound, wherein the substituted metal phthalocyanine is substituted with at least one of a halogen group, a hydroxyl group, an amine group, an alkyl group, an aryl group, a thiol group, an alkoxy group, a nitrosyl group, or combinations thereof, and wherein the unsubstituted metal phthalocyanine or the substituted metal phthalocyanine comprises a metal selected from vanadium (V), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), and combinations thereof . 14. The method of claim 13 , wherein the amine compound comprises a primary or secondary polyamine having a carbon length of from C2 to C20. 14. The method of claim 13, wherein the amine compound comprises at least one polyamine compound selected from ethylenediamine, propane- 1,3 -diamine, butane-1,4-diamine, pentane-1,5-diamine, hexamethylenediamine, diethylenetriamine, benzene-1,3,5-triamine, and combinations thereof. 14. The method of claim 13, further comprising contacting the hydrocarbon containing mercaptan sulfur and the aqueous caustic solution on a fiber bundle , wherein reacting the portion of the mercaptan sulfur and the aqueous caustic solution to produce mercaptides occurs within the fiber bundle.

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