JPH0250899B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for sulfonating organic compounds and an apparatus therefor.

BACKGROUND OF THE INVENTION Sulfonation processes (ie sulfonation and sulfation processes, respectively) have been employed in technology for a long time and have gained considerable importance, particularly in the production of cleaning raw materials. In West Germany alone, each year more than 200,000 tons (100% active substance) of anionic cleaning raw materials are produced from alkylbenzenes and from natural or synthetic fatty alcohols or fatty alcohol-polyglycol ethers and olefins. Manufactured. Currently, these preparations are carried out exclusively using gaseous sulfur trioxide, since sulfonation with fuming sulfuric acid or chlorosulfonic acid has significant disadvantages known to those skilled in the art. This gaseous sulfur trioxide is generally obtained by combustion of sulfur followed by catalytic oxidation of _SO2 to _SO3 . In contrast, the stripping of fuming sulfuric acid to obtain SO ₃ currently has little economic importance since the regeneration or recovery of residual sulfuric acid makes this process expensive.

On the other hand, demand for liquid sulfur trioxide is gradually increasing as a starting material for gaseous SO ₃ necessary for sulfonation. The use of this material has the great advantage that the sulfonation plant can be operated more flexibly, since there are no problems with its supply or removal. On the other hand, plants producing sulfur trioxide in gaseous form directly from sulfur via a catalytic process cannot be easily switched over because the catalytic furnace cannot be cooled.

A fundamental drawback of conventional sulfonation plants operating with liquid or gaseous SO ₃ is that sulfur trioxide cannot be reacted directly with the organic materials used. Although various attempts have been made to bring more or less undiluted liquid SO ₃ into contact with the organic phase, due to the extremely high reactivity of SO ₃ and the simultaneous occurrence of side reactions due to immediate oxidation of the organic material, Almost without harmful side reactions and without unacceptable and dangerous heating of organic materials by known methods.
It is not possible to carry out the sulfonation with the desired yield of 100%.

Therefore, the use of dry air as a suitable diluent for sulfur trioxide is also recommended, for example by Kremers (F.
J. Kremers and A. Schultz, "Soap & Chemical Specialties", 1970
As described in June 2006, page 44 et seq., sulfonation has been commonly used for a long time as a gas-liquid phase reaction. The above-mentioned high reactivity of liquid sulfur trioxide and its oxidizing power necessarily require that SO ₃ be operated in air at very low concentrations, ie at levels in the amount of 5% by volume. Therefore, a disproportionately large amount of air has to be passed through the reactor and must be completely separated from the reaction products again after the reaction. Furthermore, the air used as a diluent must be thoroughly dried beforehand. That is, it must be dried to a condensation point of at least -50°C in order to prevent the undesirable formation of sulfuric acid in the equipment.

Various types of reactors are known and used for specific sulfonation, but in all plants the required air is compressed and dried and a partial stream is passed to an evaporator for liquid sulfur trioxide. feed, where this partial stream is loaded with gaseous SO ₃ . This partial stream is then mixed with the remaining air stream and transferred to its own reaction chamber. However, this method uses a large amount of energy,
There have also been many attempts to recirculate the dry air recovered from the process after the reaction, but to date no plant is known in which such recirculation has been successfully implemented. Therefore, the major advantage of using stabilized liquid sulfur trioxide as the reaction medium for the sulfonation process is at least partially offset by the expensive air preparation.

The direct use of liquid or gaseous SO ₃ in the sulfonation of organic compounds is favored by two reasons: its very high oxidizing power, which leads to immediate combustion on contact with the organic material, and the very strong thermal effect of the sulfonation, i.e. Starting from the fact that about 167 KJ/mol is not yet possible, the high purity made it possible to solve these problems and to use the sulfur trioxide directly without using dilution air together. Attempts have been made to provide methods that allow the production of high yields of sulfonated products.

This fundamental problem of the invention is solved by a method for continuously sulfonating liquid organic compounds by the use of sulfur trioxide, which method comprises continuously feeding liquid organic compounds into the core of a homogenizer. and then, after the formation of a monolayer in the serpentine working zone of the homogenizing stator, with liquid or gaseous sulfur trioxide, which is continuously fed in a stoichiometric feed into the stator with feed conduits. reacting and finally removing the reaction product from the homogenizing stator, in which case the homogenizing device consists of a housing as a stator with a rotatable frusto-conical rotor therein, the rotary characterized in that the child surface comprises several coaxial rings with stepped diameters, each rotor ring being staggered with similar rings on the inner wall of the housing opposite the rotor; It will be done.

According to the invention, the stator also comprises a housing with a frusto-conical rotor rotatable inside, the rotor surface being provided with a stepped diameter perforated and/or toothed ring. , in an apparatus for the continuous sulfonation of liquid organic compounds with sulfur trioxide of the type in which the rotor rings are arranged alternately with similar rings on the inner wall of the housing opposite the rotor; It has at least one ring with at least one hollowed-out tooth or a tooth configured at least partially as a frit on the top and a nozzle for supplying sulfur trioxide. and a feeding device terminating in the ring described above.

When carrying out this process, the organic phase and the sulfur trioxide are thoroughly mixed in the working zone of the homogenizer in the shortest possible time and in such small quantities that the thermal effects of the reaction can easily be kept under control. Since sulfonation occurs naturally, the high degree of partitioning of the reactants provided within the serpentine working zone of the device makes virtually the entire amount of sulfur trioxide available for binding to organic molecules in extremely short residence times, and The reaction product can be obtained in high yield. After leaving the reaction zone, the reaction product is removed from the homogenizer, preferably with cooling, and then fed to a correspondingly large heat exchanger.

According to one embodiment of the method, it is possible to circulate part of the cooled reaction product and mix it with the fresh organic substance, so that the mixture is introduced into the center of the homogenizer, Reacts with supplied sulfur trioxide. The reaction product is then diluted with an inert reaction product which acts as a large heat sink for receiving the heat of reaction. As a result, the reaction can be maintained under control without any difficulty.

According to yet other embodiments, it is also possible to carry out the sulfonation in several steps. In this variant,
Several rotor-stator-homogenizers are arranged in series between each of the heat exchangers. The total amount of sulfur trioxide required for the sulfonation is fed in predetermined partial streams to each machine and reacts there.

Suitably, the organic compound and sulfur trioxide are added via a metering pump or other suitable metering device.

Organic compounds suitable for use in the present invention are oils, fats, fatty acids and their derivatives, but especially fatty alcohols, α-olefins, alkylarylbenzenes, linear alkylbenzenes. It is. Next, the method will be explained in detail based on the sulfonation of alkylbenzene.

Example Commercially available industrial grade alkylbenzene (average molecular weight
242) The rotor - stator - shown in the drawing weighs 375.78Kg.
Add continuously and uniformly to the working zone of the homogenizer using a suitable metering device. At the same time, 124.22 kg of liquid sulfur trioxide required for the stoichiometric reaction is fed into the serpentine turbulent action zone of the homogenizer. The temperature of the two reactants is 20°C upon introduction into the homogenizer. The reactants are rapidly mixed with each other in the working zone of the homogenizer and allowed to react in the zone by means of fine distribution without local heating, yielding 500 Kg of alkylbenzenesulfonic acid. The acid is removed from the homogenizer under cooling and passed through a heat exchanger before being neutralized with a suitable neutralizing agent such as NaOH, KOH, triethanolamine or ammonia. A second homogenizer can be used for neutralization.

An embodiment of a homogenizing device for carrying out the method of the invention is shown in the accompanying drawing, in which its essential features are depicted. Although the drawing shows essential parts, the position of the rotor axis and details of non-essential parts are omitted. The device consists of a housing 1 functioning as a stator with a frusto-conical rotor 2 rotating therein. The jacket surface of the rotor is provided with coaxial rings of stepped diameter, each alternating with a similar ring on the inner housing wall opposite the rotor. In this way, the meander-shaped working zone of the homogenizer is formed. At least one of the rings 3 of the inner wall of the housing is hollowed out or at least partially designed as a frit 4, through which sulfur trioxide can be fed into the homogenizer via a nozzle 6 of a feeding device 5. . A cooling sleeve 8 surrounds the working zones of the stator and rotor and the product outlet 7.

The main advantage of the new method is that it eliminates the air conditioning required in conventional methods, resulting in considerable energy savings. i.e. air 1000
m ³ only about 50 KW, or about half of the total electrical energy consumption of this type of plant, is required. Furthermore, the emission of harmful substances, which cannot be avoided in the case of conventional methods when air is discharged from the plant, can be avoided by the method of the invention.

Advantageously, stabilized SO ₃ is used.
Stabilizers can be removed if necessary before use in the reaction.

[Brief explanation of the drawing]

The drawing is a partial sectional view showing an example of the device of the present invention. DESCRIPTION OF SYMBOLS 1...Housing, 2...Rotor, 3...Coaxial ring, 4...Fritt, 5...Sulfur trioxide supply device,
6... Nozzle, 7... Product outlet, 8... Cooling sleeve.

Claims (1)

[Scope of Claims] 1. A liquid organic compound is continuously fed into the central part of a homogenizing device, and then after the formation of a monomolecular layer in the serpentine working zone of this homogenizing device, a fixed device equipped with a feeding conduit is provided. reaction with liquid or gaseous sulfur trioxide which is continuously fed in stoichiometric amounts to
Finally, the reaction product is removed from the homogenizer, the homogenizer comprising a housing as a stator with a rotatable frusto-conical rotor inside, the rotor surface being stepped. of sulfur trioxide, characterized in that it comprises several coaxial rings with a diameter of Continuous sulfonation method for liquid organic compounds. 2. A method according to claim 1, wherein sulfur trioxide is supplied in the stoichiometric amount required for complete sulfonation of the organic compound. 3. A method according to claim 1 or 2, in which stabilized sulfur trioxide is used and, if necessary, the stabilizer is removed before the reaction. 4. Recovering a portion of the cooled reaction product, mixing it with fresh organic material and conducting this mixture into the center of the homogenizer to react with the supplied partial stream of sulfur trioxide. The method described in section. 5 Sulfonation is carried out in several steps, several rotors connected to each other with a heat exchanger connected in between.
5. The method according to claim 1, wherein the stator-homogenizer is supplied with a portion of the total amount of sulfur trioxide required for the sulfonation. 6 Consists of a housing 1 as a stator with an internally rotatable frustoconical rotor 2, the rotor surface comprising a perforated and/or toothed ring of stepped diameter, said rotor ring In an apparatus for the continuous sulfonation of liquid organic compounds with sulfur trioxide, the rings are arranged alternately with similar rings on the inner wall of the housing facing the rotor, respectively. at least one ring 3 with two hollow teeth or teeth configured at least partially as a frit 4 and a feeding device 5 terminating in said ring with a nozzle 6 for feeding sulfur trioxide. An apparatus for sulfonating a liquid organic compound, comprising: 7. Device according to claim 6, which surrounds the working zones of the stator 1 and the rotor 2 as well as the product outlet 7.