The method of obtaining the unsaturated dimers-methylstyrene

 

(57) Abstract:

Usage: petrochemistry. Essence: dimerization-methylstyrene is carried out in the presence of a catalyst is zeolite Y NaH in form, with the degree of ion exchange of 40-60%. The amount of catalyst is 5-20 wt.%, the reaction temperature 60-140oC. effect: increase the selectivity and the simplification of get-methylstyrene. table 1.

The invention relates to the field of petrochemical synthesis, namely the method of obtaining a linear unsaturated dimer-methylstyrene.

Linear dimers-methylstyrene - 4-methyl-2,4-diphenylpentane-1 (I) and 4-methyl-2,4-diphenylpentane-2 (II) are used as solvents for lacquers, dielectric fluid, the modifiers in the production of various polymers.

A method of obtaining unsaturated dimers-methylstyrene by oligomerization of its acidic clays, such as montmorillonite, bentonite, attapulgite or montmorillonite treated with sulfuric acid [patent 1530430, UK] . The composition of the reaction products largely depends on the conditions. For more selective formation of unsaturated dimers reaction is carried out in the presence of additives aldehydes, ketones, alcohols. ethyl-3-phenylindane (III). Maximum conversion-methylstyrene in the experiments was 95 wt.%, the yield of the fraction of dimers obtained by distillation of the reaction mass is 87 wt.%. In the composition of the fractions contains 98 wt.% unsaturated dimer I, II, and 2 wt.% cyclic dimer III. In other experiments the output of the dimer fraction was 77-82% by weight, the content of the cyclic dimer from 2 to 10 wt.%. The residue after evaporating device is a polymer, its quantity is 12 wt.% and more.

A significant disadvantage of this method is the presence in the reaction mass an additional component (aldehydes, ketones, alcohols), which must then be removed and preferably regenerated and which may be present in the target product, polluting it.

Closest to the proposed invention, the technical solution chosen as a prototype, is a method for unsaturated dimers-methylstyrene, carried out by oligomerization him on the zeolite Y in the presence of solvent - methylene chloride [VP Talsi, C. P. Doronin, I. P. Sorokin and others About some methods of oligomerization-methylstyrene.// ZH. 2000. So 13. 5. S. 787]. Conversion-methylstyrene is 98,4 to 99.9 wt.%, the selectivity of the formation of linear not the number of catalyst - 60-90 wt.% on-methylsterol. The reaction was carried out at a temperature of 25-40oC for 1-2 hours, the Solvent is CH2CL2there can be not only eliminated, but replaced by any other solvent due to the low conversion-methylstyrene.

The disadvantages of this method include:

1. The presence of a solvent CH2CL2quite expensive and used in large quantities to 70 wt.%. Conducting the reaction in a solvent complicates the technology of oligomerization, as it becomes necessary stage rectification, and therefore, you receive the additional equipment and additional energy costs.

2. In the process of distillation of the reaction mass is subjected to temperatures that can cause changes in the composition of the reaction mass and deterioration of the quality of the target product.

3. High consumption of catalyst (60-90 wt.% for raw materials) due to a lack of high activity.

4. The low selectivity of the formation of unsaturated dimers - 76,1-87%.

The aim of the present invention is to increase the selectivity and simplified method of producing unsaturated dimers-methylstyrene.

This goal is achieved by the fact that an str to the invention, in the presence of zeolite Y in NaH-form with a degree of exchange of Na ions, equal to 40-60% when the reaction temperature 60-140oAnd the amount of catalyst 5-20 wt.%.

Comparative analysis of the proposed solutions with the prototype shows that the inventive method differs from the prototype in that the oligomerization-methylstyrene to unsaturated linear dimers as a catalyst using zeolite Y in NaH-form with a degree of exchange of sodium ions, equal to 40-60%. The oligomerization is carried out at a temperature of 60-140oWith the amount of catalyst is 5-20 wt.%. The selectivity of the formation of unsaturated dimers-methylstyrene I and II reaches of 87.0-96.9% of the conversion of raw materials was 94.9-100 wt.%.

The resulting reaction mass contains 0-5,1 wt.% unreacted-methylstyrene, 83,5-to 96.9 wt.% dimers I and II, of 0.9 to 6.7 wt.% cyclic dimer III, 2,2-8.6 wt.% the trimers. Tetramer-methylstyrene and more high-molecular compounds are absent. Reaction mass of such composition without any additional processing can be used, for example, as a modifier in the production of polymers. Therefore, will not require additional capital and energy intensive surgery to remove any reactants (implementing a VAT residue.

The proposed method is as follows.

Oligomerization-methylstyrene conduct periodic method. In use, the zeolite Y in the Na form, produced by JSC "Salavatnefteorgsintez". NaH-form zeolite obtained after treatment of the samples with a solution of NH4NO3at 60oWith up to a certain residual Na2O and calcining them at 500oC for 4 h

Raw materials (-methylsterol) is loaded into the reactor and the temperature of the reaction 60-140oTo download portions of the catalyst. The suspension is stirred at the reaction temperature for 1-2 hours. After a certain period of time take samples and analyzed by GLC on a chromatograph brand "Chrome 5". Condition analysis: glass capillary column 0,2-0,25 mm m with a stationary liquid phase SE-30 linear programming temperature from 60 to 270oWith speeds of 6oC/min carrier Gas is helium, the speed of the carrier gas 1-2 ml/min, the ratio of the flow of carrier gas through the column and the bypass 1:100.

The proposed method is illustrated by the following examples (see. table).

Example 1. In a heated glass reactor with stirrer, reflux condenser and thermometer load 100 g-metelli the stock exchange, equal to 60%. The suspension is stirred at 100oC for 1 hour. After cooling and filtering off the catalyst was prepared by 98.7 g of the reaction mixture composition, wt.%:

-Methylsterol - 4,8

4-Methyl-2,4-diphenylpentane-1 - 66,0

4-Methyl-2,4-diphenylpentane-2 - 20,5

1,1,3-Trimethyl-3-phenylindane - 4,5

The trimer - 4.2V

Examples 2-14. Analogously to example 1. Conditions and results of examples presented in the table.

The method of obtaining the unsaturated dimers-methylstyrene by oligomerization-methylstyrene in the presence of a catalyst of zeolite Y, characterized in that the catalyst used zeolite Y NaH in form, with the degree of ion exchange of 40-60% in the amount of 5-20 wt. %, and the reaction is carried out at a temperature of 60-140oC.

 

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