CS257139B1 - Process for preparing secondary monoalkylbenzene - Google Patents

Abstract

The solution relates to the method of secondary production alkylbenzene for alkyl detergents 9 to 16 carbon atoms. The method of production is based on proportioning distillation residue from the production of alkylbenzene excess aluminum chloride complex from the production of alkylbenzene under Friedel-Crafts conditions reactions.

Description

BACKGROUND OF THE INVENTION The present invention relates to a process for the preparation of tinalkylbenzene for synthetic detergents from benzene, linear olefins, or chloroalkanes. having 9 to 16 carbon atoms under Friedel-Crafts conditions.

For several decades, alkylbenzene has been used to make synthetic detergents. The alkyl chain usually consists of 10 to 13 carbon atoms and the benzene ring is statistically distributed over its entire length. Alkylbenzene for detergents is produced by a variety of processes that differ in the alkylation raw material and in the catalyst. In the production of olefins, hydrogen fluoride is the most commonly used catalyst, but aluminum chloride may also be used. When starting from linear alkanes, these are first chlorinated and with this mixture benzene is alkylated under the catalytic action of aluminum chloride.

According to the technological conditions, various by-products are produced, e.g. dialkylindanes, dialkylltetralins, dialkylbenzene and from chloroalkanes and diphenyl alkanes. By studying the mechanism of alkylation of benzene with both olefins and chloroalkanes, it was found that in the first stage dialkylbenzene is formed and this is disproportionate with benzene to monoalkylbenzene to equilibrium.

The formation of dialkylbenzene to polyalkylbenzene cannot be prevented, but their formation is suppressed differently. The general process for producing alkylbenzene from alkanes involves the following operations: chlorination of an alkane to a certain degree, alkylation of benzene under the catalytic action of aluminum chloride in the form of an organic complex, separation, washing of the alkylation mixture and distillation thereof. The final distillation residue is the so-called. a heavy alkylate or a polycondensate containing predominantly dialkylbenzene and the aforementioned compounds. Unreacted benzene and alkanes are recycled to the process, similar to catal. complex.

The heavy alkylate is used e.g. for the production of low-setting oils, thermal carriers, synthetic emulsifiers. Most preferably, however, it is used to obtain monoalkylbenzene by disproportionation, to shift the chemical equilibrium, or to activate the catalyst complex.

Authors in US P 3 272 881 recommend! to the distillation residue from the production of alkylbenzene at 60 ° C add aluminum chloride up to 25% either in one portion or in portions. The reaction is allowed to proceed for 2 to 9 hours to yield up to 48.5% monoalkylbenzene. According to the procedure described in Czechoslovak! AO 199 342, it is recommended to add the polycondensate in an amount of 2 to wt. % of the purifying phase catalysts of the phosphate complex which can activate with aluminum chloride up to 0.9 wt. A disadvantage of this and the foregoing process is that the polycondensate is disproportionated with powdered aluminum chloride.

In the process of producing alkylbenzene, part of the catalyst complex is recycled, the remainder is hydrolyzed with water. This complex itself still has high activity and can be used immediately to produce alkylbenzene from polycondensate (distillation residue). The process is carried out at temperatures up to 80 ° C, preferably 40 to 60 ° C. The weight ratio of the polycondensate to the catalyst sludge may vary according to the activity of the complex in a ratio of 5: 1 to 1: 5, preferably 1 to 3 to 1 s 1.

The reaction time depends on the temperature and after about 5 hours under optimal conditions the composition of the mixture changes only slightly.

Example 1

The distillation residue from the production of alkylbenzene from C ₁₀ -C ₁₃ chloroalkanes in an amount of 3 kg was heated with 3 kg of the catalyst complex to 30 ° C and stirred vigorously for 5 hours. After separation of the complex, washing and distillation, 17.1 wt. secondary monoalkylbenzene having a C ₁₀ chain up to the polycondensate.

Example 2

0.6 kg of distillation residue from the production of alkyl benzene to the olefins _of C _{9 Cl 3} was mixed with 3 kg of aluminum trichloride catalyst complex. After stirring for 2 hours at 80 degrees Celsius and working up as in Example 1, 24.8 wt. sec-monoalkylbenzene having a chain C to C ( ₃ relative to the polycondensate).

Example 3

To 900 g of polycondensate heated to 60 ° C was added 550 g of catalyst complex over 20 minutes. The polycondensate was obtained from the alkylation of benzene with a mixture of olefins and chloroalkanes with a C ₉ -C ₁₃ alkyl under Friedel-Crafts reaction conditions.

After stirring for four hours at this temperature and separation of the complex, washing and distillation, 31.3 wt. sec-monoalkylbenzene having C ₉ -C ₁₃ alkyl relative to the polycondensate.

Claims (1)

SUBJECT A process for producing a secondary monoalkylbenzene for C ₉ -C ₁₈ alkyl detergents from linear olefins or C 9 -C 16 chloroalkanes, or a mixture thereof and benzene under the catalytic effect of an aluminum chloride complex, characterized in that the distillation residue from the alkylbenzene mixed with an aluminum chloride complex separated after alkylation from the alkylation mixture in a weight ratio of 5: 1 to 1: 5 at a temperature of up to 80 ° C, preferably 40 to 60 ° C for 1 to 5 hours, preferably 2 hours.