The method of obtaining the unsaturated dimers-methylstyrene
(57) Abstract:Usage: petrochemistry. Essence: dimerization-methylstyrene is carried out in the presence of a catalyst of zeolite Y in NaH-form with the degree of ion exchange 60-95%, previously subjected to heat treatment at 500-700oIn an atmosphere of air. 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 education nanasawa predominantly (up to 95 wt. %) cyclic saturated dimer-methylstyrene - 1,1,3-trimethyl-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 2-10 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 solvents - 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-myinterface-methylstyrene in CH2Cl2is about 30%, 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 of rectification and, therefore, you receive the additional equipment and the additional energy consumption;
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) 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.
oAt a 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 are used as catalyst zeolite Y in NaH-form with a degree of exchange of Na ions, equal to 60-95%, previously subjected to high-temperature treatment in an atmosphere of air at 500-700oC. the oligomerization is carried out at 60-140oWith the amount of catalyst is 5-20 wt.%. The selectivity of the formation of unsaturated dimers-methylstyrene I and II reaches 87,2-96,1% conversion of raw materials to 96.2-100 wt.%.Dimerization-methylstyrene in the presence of zeolite NaH-Y with the degree of ion exchange of more than 60 wt.% proceeds with the formation of significant amounts of cyclic III dimer and trimer. The preliminary heat treatment of the catalyst at high temperatures of 500-700oC for 6 h in air atmosphere allows you to change its catalytic properties in such a way that the output III and trimers is reduced, and the concentration of dimers I and II in the aqueous zeolite NaH-Y with a degree of exchange of Na ions 60-95% contains 0-3,8 mass. % unreacted-methylstyrene, 87,0-94,0 wt.% dimers I and II, 1.5 to 5.7 wt. % cyclic dimer III, 2.1 to 7.6 wt. % of 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 chemicals (such as solvents), by distillation of the unreacted monomer, the selection of the target fractions, removal and disposal of 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 Heat treatment is carried out at 500-700oC in air for 6 hRaw materials (-methylsterol) is loaded into the reactor and the temperature of the reaction 60-140oPortions upload a catalyst which indicate the samples and analyzed by GLC on a chromatograph brand "Chrome 5". Condition analysis: glass capillary column of 0.2-0.25 mm x 20 m with a stationary liquid phase SE-30 linear programming temperature from 60 to 270oWith speeds of 6oC/min, carrier Gas - 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-methylstyrene and start to heat up. When 90oTo download portions of 10 g of zeolite in NaH-form with the degree of ion exchange, equal to 60%, subjected to preliminary heat treatment at 500oC. the Suspension is stirred at 90oC for 1 h, After cooling and filtering off the catalyst was prepared in 98.5 g of the reaction mixture composition, wt.%:
-Methylsterol - 1,5
4-Methyl-2,4-diphenylpentane-1 - 78,4
4-Methyl-2,4-diphenylpentane-2 - 12,6
1,1,3-Trimethyl-3-phenylindane - 2,0
Trimers of 5.5
Examples 2-10. 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 is BMENA 60-95% in the amount of 5-20 wt. %, which is previously subjected to heat treatment at 500-700oIn an atmosphere of air, and the reaction is carried out at 60-140oC.
FIELD: petrochemical processes.
SUBSTANCE: method provides for three-stage isolation of aromatic hydrocarbons in the separation, absorption, and separation stages using, as absorbent, ethylbenzene rectification bottom residue. Loaded absorbent containing diethylbenzene isomer mixture serves as starting material for production of alkylaromatic hydrocarbons including divinylbenzene.
EFFECT: reduced loss of aromatic hydrocarbons and improved economical efficiency of styrene production process.
2 dwg, 1 tbl, 5 ex