JP4069654B2 - Method for producing cycloalkene - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a process for the selective conversion of cycloalkadienes to cycloalkenes.
[0002]
[Prior art]
Using cyclopentadiene (CPD) as a cycloalkadiene, only one carbon-carbon double bond is selectively hydrogenated (partial hydrogen) out of two carbon-carbon double bonds present in the molecule of the CPD. And a method for producing cyclopentene (CPE) as a cycloalkene is known.
[0003]
However, since the reaction proceeds from CPD → CPE → cyclopentane (CPA), if an attempt is made to add hydrogen so that unhydrogenated CPD does not remain, CPA is generated. In this case, the reaction rate of CPD is high, but the selectivity of CPE is low, and as a result, the yield of CPE decreases. On the other hand, when trying to suppress the production of CPA, it becomes difficult to completely react CPD. In this case, the selectivity of CPE is high, but the reaction rate of CPD is low, and as a result, the yield of CPE decreases. That is, in the conventional method, the reaction rate of CPD and the selectivity of CPE are low, and as a result, it is difficult to improve the yield of CPE.
[0004]
Therefore, conventionally, in order to produce CPE with a relatively high selectivity, a reaction vessel equipped with a stirring blade inside was used, and a partial hydrogenation reaction of CPD was performed in this reaction vessel. Specifically, hydrogen was blown in while stirring the CPD in the reaction vessel while rotating the stirring blade in the reaction vessel, and hydrogen was brought into contact with the CPD to carry out the partial hydrogenation reaction of CPD.
[0005]
[Problems to be solved by the invention]
However, when the partial hydrogenation reaction of CPD is performed in a reaction vessel equipped with a stirring blade, the CPD reaction rate is slow and the CPD is converted to CPE in a short time, while a relatively high CPE selectivity is obtained. Had a problem with doing.
[0006]
In British Patent Publication No. 2273107, CPD as a cycloalkadiene is used, and two carbon-carbon double bonds existing in the molecule of the CPD are all hydrogenated (completely hydrogenated) to form a cycloalkane. A method for producing CPA has been proposed. In this method, hydrogen is blown into a circulation pipe connected to a reaction vessel so that hydrogen is brought into contact with CPD flowing in the circulation pipe and CPD is completely hydrogenated to produce CPA. is there. However, this method is intended for the production of CPA and does not produce any CPE.
[0007]
An object of the present invention is to provide a method capable of improving the reaction rate of a cycloalkadiene such as CPD without reducing the selectivity of a cycloalkene such as CPE, and producing a cycloalkene in an industrially advantageous manner. It is to be.
[0008]
[Means for Solving the Problems]
The present inventors have found that there is a correlation between the linear flow rate of the reaction liquid when contacting hydrogen and the reaction rate of cycloalkadiene. It was also found that the reaction rate of cycloalkadiene can be improved without decreasing the selectivity of cycloalkene by controlling the linear flow rate of the reaction liquid during hydrogen contact.
[0009]
That is, according to the present invention,
Extracting the reaction solution from the liquid phase part of the reaction vessel, flowing the reaction solution through a circulation pipe connected to the reaction vessel while controlling the linear flow rate, and circulating the reaction solution toward the reaction vessel;
There is provided a method for producing cycloalkene, comprising the steps of blowing hydrogen into a liquid phase part in a reaction system and bringing hydrogen into contact with a reaction liquid flowing in the circulation pipe.
[0010]
Hydrogen may be blown into the liquid phase part in the reaction system. For example, hydrogen may be blown from the sparger installed in the reaction vessel, or may be blown into the circulation pipe, but is preferably blown into the circulation pipe.
[0011]
According to this invention, the reaction rate of cycloalkadiene can be improved without reducing the selectivity of cycloalkene by controlling the linear flow rate of the reaction solution flowing in the circulation pipe. It is defined that the shorter the time required for the cycloalkadiene reaction rate to reach 100%, the faster the reaction rate.
[0012]
In the present invention, it is preferable to control the linear flow rate of the reaction liquid flowing in the circulation pipe to 1.0 m / second or more. By setting the linear flow rate to 1.0 m / second or more, the reaction rate of cycloalkadiene can be greatly improved.
[0013]
In the present invention, it is preferable to contact hydrogen with the reaction solution in the presence of alkanolamine having 2 to 4 carbon atoms using nickel as a catalyst. Moreover, it is preferable to use Raney nickel as nickel. Moreover, it is preferable to make hydrogen contact a reaction liquid at 40 degrees C or less.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
[0015]
Examples of the cycloalkadiene that can be used in the method of the present invention include CPD, methylcyclopentadiene, methylcyclohexadiene, and cyclooctadiene.
[0016]
In the following description, CPD is exemplified as a cycloalkadiene, and a method for producing CPE by partially hydrogenating the CPD will be described.
[0017]
The partial hydrogenation reaction of CPD is a reaction that selectively saturates only one carbon-carbon double bond among the two carbon-carbon double bonds present in the molecule of CPD.
[0018]
CPD used for the production of CPE is a known substance having a boiling point of 41 to 42 ° C. and is contained in the C5 fraction of naphtha cracked oil by 15 to 20%. The method for producing such CPD is not particularly limited, and examples thereof include a method of thermally decomposing or depolymerizing dicyclopentadiene (cyclopentadiene dimer, DCP).
[0019]
CPD may be used alone or diluted with a solvent. When CPD is diluted with a solvent, dimerization of CPD can be suppressed. Examples of the solvent used for dilution include cyclic unsaturated hydrocarbons such as CPE, aliphatic hydrocarbons, aliphatic ethers, aliphatic alcohols, aromatic hydrocarbons, and aromatic ethers. These solvents may be used alone or in combination of any two or more. Although the usage-amount in the case of using a solvent is not specifically limited, It is 5-3000 weight part normally with respect to 100 weight part of CPD, Preferably it is 10-2000 weight part.
[0020]
As a method of mixing CPD and a solvent, for example, CPD prepared in advance and a solvent may be mixed.
[0021]
In addition, in the partial hydrogenation of CPD, an inert gas that does not interfere with the reaction may be used in combination with the solvent. Examples of the inert gas include nitrogen gas, helium gas, argon gas, and carbon dioxide gas. The amount used is not particularly limited, but is usually 0.001 to 0.1 mol, preferably 0.001 to 0.05 mol, relative to 1 mol of CPD.
[0022]
The hydrogenation catalyst used for the partial hydrogenation of CPD is not particularly limited. For example, palladium, nickel, copper, or other metals (chromium, titanium, silver, zinc, cadmium, thallium, lead, iron, ruthenium) , Rhodium, cobalt, rhenium, etc.) may be used in combination. These catalysts can be supported on a carrier and used as a supported catalyst. The type of the carrier is not particularly limited, and a carrier for catalyst generally used in industry is used. Specific examples of the carrier include activated carbon, magnesium oxide, α-alumina, α-alumina supporting an alkaline earth metal, titania, and the like.
[0023]
Of these, nickel is preferably used, and Raney nickel catalyst is particularly preferably used. The Raney nickel catalyst referred to here includes not only ordinary Raney nickel but also so-called modified Raney nickel (see page 539, published on February 15th, 1987, “Chemical Dictionary 9”, page 539).
[0024]
The Raney nickel catalyst can be produced, for example, as follows. First, 40 g of Raney nickel aluminum alloy (50% nickel) is added to a 1 liter three-necked flask containing 600 ml of 10% sodium hydroxide solution in small portions with mechanical stirring for 20-30 minutes. To do. The temperature is kept at 90-95 ° C. during this addition. The mixture is stirred for an additional hour, stirring is stopped, the nickel is allowed to settle, and the solution is separated by decanting. The metal is washed 5 times with 200 milliliters of water and then 5 times with 50 milliliters of ether, so that the nickel is always immersed in the liquid. The catalyst is then stored in ethanol and refrigerated for further use.
[0025]
The usage-amount of a hydrogenation catalyst is 0.01-30 weight part normally with respect to 100 weight part of CPD, Preferably it is 0.1-15 weight part. If it is 0.01 parts by weight or less, the reaction time is long and the productivity is lowered. On the other hand, if it exceeds 30 parts by weight, the hydrogenation selectivity is lowered, which is not preferable.
[0026]
The partial hydrogenation of CPD is preferably performed in the presence of an alkanolamine having 2 to 4 carbon atoms together with a hydrogenation catalyst. By performing in the presence of an alkanolamine having 2 to 4 carbon atoms, the amount of CPD contained in the obtained CPE can be substantially zero, and the purity can be improved.
[0027]
The alkanolamine having 2 to 4 carbon atoms may be a monoalkanolamine or a dialkanolamine. Moreover, although a monovalent amine or a bivalent amine may be sufficient, a monovalent amine is preferable. Specific examples of the alkanolamine having 2 to 4 carbon atoms include ethanolamines such as monoethanolamine, N-methylethanolamine, N-ethylethanolamine; 3-amino-1-propanol, 2-amino-1-propanol Propanolamines such as 1-amino-2-propanol; 4-amino-1-butanol, 3-amino-1-butanol, 2-amino-1-butanol, 3-amino-2-butanol, 4-amino- Butanolamines such as 3-butanol and 4-amino-2-butanol; diethanolamine; and the like.
[0028]
The amount of the alkanolamine used is 0.05 to 50 parts by weight, preferably 0.05 to 10 parts by weight with respect to 1 part by weight of the hydrogenation catalyst. If it is 1 part by weight or less, the hydrogenation selectivity becomes poor, and if it exceeds 50 parts by weight, the productivity is lowered.
[0029]
The partial hydrogenation of CPD is preferably performed using water as a medium. The amount of water in this case is usually in the range of 0.1 to 10 parts by weight, preferably 0.1 to 5 parts by weight with respect to 1 part by weight of CPD. If the amount of water is too large relative to CPD, the selectivity in the hydrogenation reaction will decrease, and if it is too small, the reaction time will be long, the productivity will decrease, and cyclopentane (CPA) will be produced as a by-product. The yield may be significantly reduced.
[0030]
In the present embodiment, first, a reaction raw material (reaction liquid) such as CPD is charged into a reaction vessel. The reaction vessel that can be used in the present invention is not limited by its shape and material, but it is preferable to use a vessel having a pressure resistance, for example, stainless steel is suitable. A stirring blade such as an inclined paddle may be provided inside the reaction vessel.
[0031]
Next, a suction means such as a pump is operated, and the reaction raw material in the reaction vessel is extracted from the reaction vessel and circulated back to the reaction vessel again through a circulation pipe connected to the reaction vessel. The inner diameter of the circulation pipe that can be used in the present invention is appropriately determined according to the scale of the apparatus, and is, for example, about 5 to 1000 mm.
[0032]
Thereafter, hydrogen is preferably blown into the circulation pipe, and hydrogen is brought into contact with CPD contained in the reaction raw material flowing through the circulation pipe to partially hydrogenate to produce CPE. In the case of this embodiment, it is preferable to blow in hydrogen from the downstream side of suction means such as a pump.
[0033]
In the present invention, the linear flow rate of the reaction raw material flowing in the circulation pipe is controlled. The linear flow rate is the flow rate per unit area. If the linear flow rate of the reaction raw material changes, the contact time with hydrogen changes regardless of the inner diameter of the circulation pipe. In the present invention, by controlling the linear flow rate of the reaction raw material flowing in the circulation pipe, the reaction rate of CPD can be improved without reducing the selectivity of CPE by adjusting the contact time with hydrogen. . Specifically, the linear flow rate of the reaction raw material flowing in the circulation pipe is preferably 1.0 m / second or more, more preferably 1.5 m / second or more.
[0034]
The partial hydrogenation of CPD is preferably performed at a temperature of 40 ° C. or lower, more preferably 20 ° C. or lower, and particularly preferably 10 ° C. or lower. When the temperature exceeds 40 ° C., dimerization of CPD occurs, and the selectivity of CPE decreases, so that the yield of CPE decreases. Further, the reaction may proceed from CPE to CPA, which is not preferable.
[0035]
The partial hydrogenation of CPD is usually performed at a pressure (gauge pressure) of 0 to 3 MPa, preferably 0 to 2.5 MPa. The higher the pressure during partial hydrogenation, the higher the reaction rate.
[0036]
In the partial hydrogenation of CPD, the amount of CPD and hydrogen can vary greatly. However, usually at least a stoichiometric amount of hydrogen is used, and the amount of hydrogen used for CPD is appropriately selected within the range of 1 to 20 equivalents. Preferably it is 1-10 equivalent.
[0037]
The partial hydrogenation of CPD can be realized, for example, using a reactor 2 as shown in FIG. FIG. 1 is a block diagram showing an example of a reaction apparatus for carrying out the method of the present invention. The reaction apparatus 2 shown in FIG. 1 has a reaction vessel 4, and a circulation pipe 6 is connected to the reaction vessel 4 in a loop shape. A pump 10 is disposed in the middle of the circulation pipe 6. The pump 10 extracts the reaction raw material 8 from the reaction vessel 4, and flows the extracted reaction raw material 8 into the circulation pipe 6 so as to return it to the reaction vessel 4 again. A hydrogen supply line 11 is connected to the downstream side of the pump 10 of the circulation pipe 6. In the middle of the circulation pipe 6, a heat exchanger 12 for removing reaction heat of the reaction raw material being circulated may be arranged.
[0038]
After completion of the partial hydrogenation reaction, the target product can be isolated by a conventional purification method such as distillation.
[0039]
【Example】
EXAMPLES The present invention will be specifically described below with reference to examples, but the scope of the present invention is not limited by these examples.
[0040]
In Examples and Comparative Examples, the reaction rate (%) of CPD indicating the reaction results and the selectivity (%) of CPE were determined by analyzing the condensed liquid (crude product) after the reaction by gas chromatography. Based on the ratio, it was calculated by the following formula 1 and formula 2.
[0041]
CPD reaction rate (%) = {(Amount of CPD consumed in reaction (mol)) / (Amount of raw material CPD (mol) charged during reaction)} × 100 (1)
CPE selectivity (%) = {(Amount of CPE produced (mol)) / (Amount of raw material CPD charged during reaction (mol))} × 100 (2)
It shows that CPE produced | generated efficiently, so that the reaction rate of CPD was large and the selectivity of CPE was large. In addition, the yield (%) of CPE is calculated by the following formula 3.
[0042]
CPE yield (%) = {(reaction rate) × (selectivity)} / 100
Example 1
First, 5 kg of CPD, Raney nickel catalyst (NDT-65, manufactured by Kawaken Fine Chemical Co., Ltd.) 0.04 kg, 0.03 kg of monoethanolamine, and 2.5 kg of water are charged as reaction raw materials 8 in the reaction vessel 4 shown in FIG. The temperature was controlled at 10 ° C. in an inert gas atmosphere.
[0043]
Next, the pump 10 is operated to extract the reaction raw material 8 from the reaction vessel 4 and return to the reaction vessel 4 through the circulation pipe (inner diameter 18.4 mm) 6 again to a linear flow rate of 1.51 m / sec (volume). It was circulated at a flow rate of 1.44 m ³ / hour).
[0044]
Thereafter, hydrogen was blown into the circulation pipe 6 through the hydrogen supply line 11 at a flow rate of 0.04 to 0.8 Nm ³ / h, and hydrogen was brought into contact with CPD contained in the reaction raw material 8 flowing in the circulation pipe 6. . The pressure (gauge pressure) of the reaction system due to the hydrogen pressure was 0.25 MPa.
[0045]
The experiment was continued in this state, and the time until the CPD reaction rate was 100% was measured. As a result, it was confirmed that the reaction rate of CPD reached 100% in 2.4 hours from the start of the reaction (average reaction rate was 41.6% / hour). Moreover, the selectivity of CPE at this time was 99.5%.
[0046]
FIG. 2 is a graph showing the relationship between the time from the start of reaction and the reaction rate of CPD.
[0047]
Comparative Example 1
The same reaction raw material as in Example 1 was put into a reaction vessel equipped with a stirring blade inside. Thereafter, while rotating the stirring blade, hydrogen was blown while stirring the reaction raw material, hydrogen was brought into contact with CPD contained in the reaction raw material, and the time for which the CPD reaction rate was 100% was measured. As a result, it was confirmed that it takes 7.5 hours to reach 100% of the reaction rate of CPD as compared with Example 1 (average reaction rate is 13.3% / hour). Further, the selectivity of CPE at this point was 91.1%, which was lower than that of Example 1.
[0048]
FIG. 2 is a graph showing the relationship between the time from the start of reaction and the reaction rate of CPD.
[0049]
【The invention's effect】
As described above, according to the present invention, the reaction rate of cycloalkadiene such as CPD can be improved without lowering the selectivity of cycloalkene such as CPE, and cycloalkene can be produced industrially advantageously. A method can be provided.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an example of a reaction apparatus for carrying out the method of the present invention.
FIG. 2 is a graph showing the relationship between the time from the start of reaction and the reaction rate of CPD in Example 1 and Comparative Example 1.
[Explanation of symbols]
2 ... Reactor 4 ... Reaction vessel 6 ... Circulation pipe 8 ... Reaction raw material (reaction liquid)
10 ... Pump 11 ... Hydrogen supply line 12 ... Heat exchanger

Claims (4)

A reaction solution containing cycloalkadiene is extracted from the liquid phase part of the reaction vessel, and the reaction solution is allowed to flow in a circulation pipe connected to the reaction vessel while controlling a linear flow rate to 1.0 m / second or more . Circulating to the reaction vessel;
And a step of blowing hydrogen into the circulation pipe and bringing hydrogen into contact with a reaction solution flowing through the circulation pipe. The method for producing cycloalkene according to claim 1 , wherein hydrogen is brought into contact with the reaction solution in the presence of alkanolamine having 2 to 4 carbon atoms using nickel as a catalyst. The method for producing cycloalkene according to claim 2 , wherein Raney nickel is used as nickel. The method for producing cycloalkene according to any one of claims 1 to 3 , wherein hydrogen is brought into contact with the reaction solution at 40 ° C or lower.

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