CS276762B6 - Process for the production of an aluminum chloride catalyst complex for catalysis in organic synthesis - Google Patents

Abstract

The solution relates to a method for producing a catalytic complex based on aluminum chloride and aromatic hydrocarbons with reduced consumption of promoter and aluminum chloride by alkylation of benzene with ethylene in the process of ethylbenzene production. The method for producing a catalytic complex of aluminum chloride for catalysis in organic syntheses, in particular for alkylation of benzene with ethylene, from a suspension of aluminum chloride, aromatic hydrocarbons and a promoter consists in that at a temperature of 10 to 90 °C, preferably 30 to 80 °C, a previously prepared catalytic complex is added in advance in an amount of 5 to 100 wt. % based on the newly formed complex and a promoter is added to this mixture with constant stirring. Water is preferably added as a promoter in an amount of not more than 2.6 kg per 100 kg of AlCl,. The solution will be widely used to reduce the specific consumption of aluminum chloride in the preparation of a liquid catalytic complex and/or to shorten its preparation time.

Description

The invention relates to a process for the preparation of a catalyst complex based on aluminum chloride, aromatic hydrocarbons with reduced promoter consumption and AlCl 3, intended for catalysis in organic syntheses, in particular in the alkylation of benzene with ethylene in the ethylbenzene production process.

Anhydrous aluminum halides, especially aluminum chloride, are important catalysts for so-called Friedel-Crafts reactions and analogous reactions such as alkylation, transalkylation, isomerization, acylation and the like.

and

Aluminum chloride, a strong Lewis acid, does not react alone with benzene or ethylene, but can form complexes with many compounds. In the presence of promoters, aluminum chloride forms active liquid complexes with alkylaromatic hydrocarbons. This ability is used in the preparation of liquid aluminum chloride catalyst complexes, which have eliminated many of the disadvantages associated with the use of aluminum chloride as an alkylation catalyst, in particular dosing and handling difficulties, different particle sizes, coating of aluminum chloride particles with catalytically inactive coating, long incubation time and similarly.

At present, in industrial alkylation processes, its liquid complexes are used almost exclusively instead of solid AlCl 3 as aluminum chloride-based catalysts.

Ethylbenzene, alkylbenzenes and polyalkylbenzenes, and / or mixtures of these hydrocarbons with benzene are usually used as aromatic components for the preparation of these complexes.

Anhydrous hydrogen chloride, chlorinated hydrocarbons and water are most commonly used as promoters for the preparation of an aluminum chloride catalyst complex with said aromatic components.

Catalytic complexes prepared with liquid water as a promoter commonly used in the process show lower activity compared to, for example, a catalytic complex prepared using steam or chlorinated hydrocarbons as a promoter. However, chlorinated hydrocarbons are not commonly available. However, the process for the preparation of the aluminum chloride complex with the addition of water as activator is the most advantageous from an operational point of view, and therefore ways are being sought to prepare a catalyst complex which has advantageous alkylation properties.

According to the invention, a process for the preparation of an aluminum chloride catalyst complex for catalysis in organic syntheses, in particular for the alkylation of benzene with low molecular weight olefins, from a suspension of aluminum chloride, aromatic hydrocarbons and a promoter consists in preparing a starting suspension of aluminum chloride and aromatic hydrocarbon C, preferably 30 to 80 ° C, a pre-prepared catalyst complex is added in an amount of 5 to 100% by weight, based on the newly formed complex, and a promoter, preferably water, is added to this mixture with constant stirring in an amount of at most 2.6 kg per 100 kg. aluminum chloride. Some of the following hydrocarbons can be used as alkylaromatic hydrocarbons for the preparation of the catalyst complex alone and / or in a mixture with benzene:

- ethylbenzene and diethylbenzene j

- ethylbenzenes

- fraction of polyalkylaromatic hydrocarbons falling off during the production of ethylbenzene with a boiling point above 136 ° C.

The preparation of the catalyst complex according to the invention can be carried out as follows: a mixture of alkylbenzenes and / or a mixture of alkylbenzenes with benzene is introduced into the vessel and the required amount of aluminum chloride is poured in with constant stirring. With constant stirring, a selected amount of the previously prepared complex and the calculated amount of promoter are added and the contents of the vessel are stirred at the desired temperature until all of the aluminum chloride is converted to a homogeneous liquid complex.

CS 276 762 B6

The obtained aluminum chloride complex is a brown-red clear homogeneous liquid with stably high catalytic activity. According to the described method, less aluminum chloride and promoter are consumed for the same amount of prepared complex. In the case of the use of water as a promoter, the saving of AlCl 2 is explained by the fact that part of AlCl 3 does not form a catalytic complex, but is hydrated according to the following equation:

_{AlCl 2} + H 2 0 --------> Al (OH) Cl ₂ + HCl

Another advantage of the described process is the stable high initial activity of the catalytic complex, which is preferably reflected in the stable catalytic activity when changing the raw material (changing the provenance of AlCl 3, changing the proportion of individual alkylbenzenes) and smoothing the alkylation reaction. The autocatalytic action of the added complex also significantly shortens the incubation time of formation. new catalytic complex · ..

The process for the preparation of the aluminum chloride catalyst complex according to the invention is illustrated by the following example:

Example 1

A specified amount of diethylbenzene fraction from the production of ethylbenzene is pumped into a closed steel enamelled vessel equipped with a stirrer and temperature measurement. The stirrer is started and the appropriate amount of aluminum chloride is poured into the vessel. The specified amount of catalyst complex is pumped into the vessel and gradually, the calculated amount of water is slowly added. The temperature in the vessel rises from the original 46 ° C to 64 to 66 ° C, and the excess heat of reaction of complex formation is transferred to the surroundings in the form of heat loss. After the water has been metered in, the contents of the vessel are stirred for a further 0.5 to 2.0 hours. The catalytic complex is obtained as a homogeneous clear red-brown liquid,

The following table shows the results of monitoring the effect of the addition of the catalyst complex on the minimum amount of water added, still sufficient for the complete dissolution of aluminum chloride (saving of decomposed AlCl 2):

Table 1: Effect of catalytic complex dosing and for consumption water and saving and aluminum chloride of that Input components of the complex: AlCl 3 (kg) 100 100 100 Diethylbenzene fractions (kg) 136 136 136 Batch of the old complex (kg) 0 120 230 * Water (kg) 2.40 1.90 1.60 Total. amount of complex (kg) 238.40 357.90 467.60. (including inactive AlOHCl ₁ ) Total. preparation time (min.) 55.0 35.0 105.0 Specific conductivity of the complex as a measure of catalytic activity (S / m) Old complex __ 0.605 0.605 New complex 0.560 0.580 .0,595 Amount of decomposed AlCl-j (kg) +17.76 14.06 .11.84. : ... AlClj savings (kg / 100 kg AlClj) - 3.70. . ; 5.92. .; . · .. + According to the above equation

CS 276 762 B6

Example 2

The description of the preparation of the complex is the same as in Example 1. In this example, the effect of catalytic complex dosing on the incubation time of new complex formation at a constant amount of added water as a promoter is monitored:

Table 2: Effect of catalytic complex dosing on the incubation time of new complex formation

Input components of the complex:

AlCl 3 (kg) Oethylbenzene fraction (kg) 100 136 100 136 100 136 Batch of the old complex (kg) 0 120 230 Water (kg) 2.40 2.40 2.40 Total. amount of complex (kg) 238.40 358.40 468,40 (including inactive AlOHCl ₁ ) Total. preparation time (min.) 55.0 25.0 10.0 Specific conductivity of the complex as a measure of catalytic activity (S / m) Old complex 0.485 0.485 New complex 0.445 0.465 0.475

From the above examples, it is clear that the invention is advantageous to use to reduce the specific consumption of aluminum chloride and / or to reduce the induction time for the preparation of the liquid catalyst complex.

Claims (1)

PATENT CLAIMS Process for the preparation of an aluminum chloride catalyst complex for catalysis in organic syntheses, in particular for the alkylation of benzene with low molecular weight oils, from a suspension of aluminum chloride, aromatic hydrocarbons and a promoter, characterized in that the starting suspension of aluminum chloride and aromatic hydrocarbon is C, preferably 30 to 60 ° C, a pre-prepared catalyst complex is added in an amount of 5 to 100% by weight, based on the newly formed complex, and a promoter, preferably water, is added to this mixture with constant stirring in an amount of at most 2.6 kg per 100 kg of aluminum chloride.