RU2151150C1 - Method of cleaning alkyl aluminum chlorides from finely dispersed solid admixtures - Google Patents

Abstract

FIELD: cleaning alkyl aluminum chlorides used as catalyst components for synthesis of various high-molecule compounds. SUBSTANCE: method consists in filtration at introduction of auxiliary agent at stage of synthesis of alkyl aluminum chlorides together with starting reagents; alkali metal chloride is used as auxiliary agent. EFFECT: intensification and simplification of cleaning process; reduced mass of solid wastes; simplified utilization of wastes. 2 cl, 5 ex

Description

The invention relates to an improved method for the purification of organoaluminum compounds (AOC) of the general formula R _n AlCl _3-n (where R = C ₂ H ₅ , iC ₄ H ₉ ; n = 1, 1.5, 2) from fine solids. AOS are used as catalyst components for the synthesis of various high molecular weight compounds.

In the industrial production of alkylaluminium chlorides obtained, for example, by the interaction of aluminum chloride with the corresponding AOC or directly from aluminum and alkyl chloride according to the following reaction equations:
2R ₃ Al + AlCl ₃ ----> 3R ₂ AlCl,
3RCl + 2Al ----> R ₃ Al ₂ Cl ₃ ,
the target product inevitably contains an admixture of a solid phase - unreacted aluminum (in the case when AOC is a raw material obtained by direct synthesis from aluminum) and / or inorganic aluminum compounds (hydroxide, oxychloride), the source of which is aluminum chloride.

 Solutions of alkyl aluminum chlorides in hydrocarbons must be cleaned of solid impurities with a particle size of less than 1.0 microns. The solids content in the initial suspension usually does not exceed 0.8 wt.%, And the solids content in the filtrate should be no more than 0.1 wt.%. The high dispersion of solid impurities contained in aluminum alkyl technical solutions necessitates the use of fine filters, which are known to have high resistance and are difficult to regenerate / 1. N.N. Korneev. Chemistry and technology of organoaluminum compounds, M., Ed. "Chemistry", 1979, p. 189-192 /.

 A known method of purifying AOC from fine impurities with the introduction of an auxiliary substance / M.C. Reybach, L.A. Fedotov et al. Purification of triisobutylaluminium by filtration using excipients, Chemical Industry, 1969, N 5, p. 377-379 /, according to which kieselguhr and perlite deposited on a filter membrane are used as an auxiliary substance. The disadvantage of this method is the relative complexity of filtering.

Closest to the proposed method according to the technical nature and the achieved result is a method of cleaning AOC from fine particulate matter by filtration / A.s. USSR N 819108, MKI ⁶ C 07 F 5/06, decl. 03/23/79. N 2740529 / 23-04, publ. 04/07/81. Bull. N 13 /, according to which a perlite fraction of 0.3-10 μm, taken in an amount of 0.1-0.3 wt. parts per 1 wt. part of solid impurities, and mix. The introduction of perlite allows the process of coagulation and sedimentation of fine suspension of solid impurities in AOC to be carried out rather quickly.

 A significant disadvantage of this method is that its implementation requires relatively large amounts of perlite, comparable with the mass of solid impurities, which complicates the further process of neutralization and disposal of fire hazardous (pyrophoric) waste due to the increase in the mass of the solid phase and the presence of an additional component in the waste - perlite.

 The invention consists in a method of purification of organoaluminum compounds from fine solid impurities by filtration with the introduction of an auxiliary substance at the stage of synthesis of organoaluminum compounds together with the starting reagents, while alkali metal chloride in an amount of 0.001-0.05 wt.% Of the mass obtained is used as an auxiliary substance alkyl aluminum chlorides, and sodium and / or potassium chloride can be used as an alkali metal chloride, which makes it possible to intensify and simplify AOC purification process from finely divided solids by filtration while reducing the weight of the solid waste, and thereby to simplify further the production of waste disposal AOC. In addition, the waste generated in the production of alkyl aluminum chlorides contains water-soluble alkali metal chloride, therefore, when water-neutralizing fire hazardous waste, which is a suspension of solid particles in a hydrocarbon solution of alkyl aluminum chloride, an aqueous solution of salts can already be obtained by varying the pH or aluminum hydroxide.

When comparing the essential features of the invention:
- an auxiliary substance is introduced at the stage of synthesis of organoaluminum compounds together with the starting reagents,
- as an auxiliary substance, alkali metal chloride is used in an amount of 0.001-0.05 wt.% by weight of the obtained alkylaluminium chloride,
- as the alkali metal chloride using sodium chloride and / or potassium,
with those of the prototype revealed that they are new and not described in the prototype. Therefore, we can conclude that the proposed technical solution meets the criterion of "novelty."

 The use of new distinguishing features allows you to clean AOC from fine impurities at the lowest cost and reduce the amount of waste generated, which is impossible to implement in any similar way and that indicates the "inventive step" of the proposed method.

 The claimed invention can be implemented on existing synthetic rubber production plants, where an organoaluminum catalyst is used in the polymerization process, which confirms compliance with the criterion of "industrial applicability".

 The presented examples illustrate the invention.

 Example 1

At the synthesis stage, 42 kg of (iso-C ₄ H ₉ ) ₂ AlCl (crude diisobutylaluminium chloride) together with the starting reagents is fed sodium chloride in an amount of 8.82 g, which is 0.021 wt.% Of the amount of diisobutylaluminium chloride. In the synthesis process, the reaction mixture is stirred at a temperature of 60 ^o C for 5 hours. The content of finely divided solid impurities is 0.9 wt.%. Then the product settles for 3 hours, after which the contents of the tank are fed to a cermet filter with an excess nitrogen pressure of 0.05 MPa. The filtration process lasts 4 hours at a temperature of 30 ^o C. The filter capacity of 17 kg / m ² • hour. No solid impurities. The conditions for the purification of AOC are shown in the table.

 Example 2

At the synthesis stage, 43 kg (C ₂ H ₅ ) ₂ AlCl (crude diethylaluminium chloride) together with the starting reagents serves sodium chloride in an amount of 0.43 g, which is 0.001 wt. % of the amount of diethylaluminium chloride. In the synthesis process, the reaction mixture is stirred at a temperature of 50 ^o C for 5 hours. The content of finely divided solid impurities is 0.8 wt.%. Then the product settles for 3 hours, after which the contents of the container are fed to a ceramic-metal cartridge filter with an excess nitrogen pressure of 0.05 MPa. The filtering process takes place within 14 hours at a temperature of 30 ^o C. Productivity of the filter 16.7 kg / m ² • hour. There are no solid impurities in the filtrate. The synthesis conditions are given in the table.

 Examples 3-5.

 Purification of AOC from fine impurities is carried out according to example 1. The conditions for the purification of AOC are shown in the table.

 As follows from the data in examples 1-5, the proposed method allows to intensify the process of cleaning AOC from fine solids.

Claims (2)

 1. A method of purifying alkylaluminium chlorides from fine solid impurities by filtration with the introduction of an excipient, characterized in that the excipient is introduced at the stage of synthesis of alkylaluminium chlorides with the starting reagents, and alkali metal chloride in an amount of 0.001-0.05 wt.% Is used as an excipient by weight of the obtained alkylaluminium chloride.  2. The method according to p. 1, characterized in that the sodium chloride and / or potassium chloride is used as the alkali metal chloride.

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