RU2424221C1 - METHOD FOR COMBINED SYNTHESIS OF LINEAR CYCLIC HOMO- AND CODIMERS OF STYRENE AND α-METHYLSTYRENE - Google Patents

Abstract

FIELD: chemistry. ^ SUBSTANCE: present invention relates to a method for combined synthesis of cyclic and linear homo- and codimers of styrene and -methylstyrene. Described is a method for combined synthesis of cyclic and linear homo- and dimers of styrene and -methylstyrene via codimerisation of monomers in the presence of an acid catalyst, characterised by that the catalyst used is zeolite H-ZSM-12 in amount of 5-30 wt % and the reaction takes place in chlorobenzene at temperature 80-130C. ^ EFFECT: simple, environmentally safe method for combined oligomerisation of styrene and -methylstyrene. ^ 2 cl, 1 dwg, 2 tbl, 8 ex

Description

The invention relates to the field of petrochemical synthesis, and in particular to a method for producing linear and cyclic homo- and codimers of styrene and α-methylstyrene.

Cyclic and linear homodimers of styrene and α-methylstyrene are used as plasticizers for polymers and rubbers, molecular weight regulators of polymers, raw materials for the production of fuels, components of synthetic oils and lubricants, solvents for paints and varnishes, high-temperature coolants [US Patents 3161692, 3792096, 3994816, 4302618, 442027, 20040242441, A.S. USSR 1036727; RF patents 2071460, 2129043, 2149862; Maier G. Angew. Chem. Im Ed. 1998, 37, p.2960-2974].

Synthesis of α-methylstyrene homodimers is carried out using various acid catalysts: mineral or organic acids [British Patent 1507600, RF Patent 2088561], cation exchange resins [B.Chaudhuri, M.M.Sharma. Ind. Eng. Chem. Res. 1989, v. 28, N12, p. 1757-1763. M. Fujiwara, K. Kuraoka, T. Yazawa. Chem. Commun. 2000, p.1523-1524], treated with clay acid [US Patent 3,116,692, 1964]. Depending on the reaction conditions and the nature of the catalyst, the main reaction products are linear (LDMS 1a, b) or a cyclic α-methylstyrene dimer (CDMS 1c)

Reaction Scheme

Zeolites and zeolite-like materials are effective catalysts for preparing linear α-methylstyrene dimers.

The work [Ya. I. Isakov, Kh. M. Minachev, V.Z. Sharf et al. Petrochemistry, 1999, vol. 39, No. 4, p. 278-283] describes a method for producing linear dimers of α-methylstyrene in the presence of crystalline aluminophosphates. In catalysts obtained from unmodified crystallite AlPO ₄ -8, at atmospheric pressure, 75-100 ° C and a WHSV of 1.5 h ^-1, the conversion of α-methylstyrene is 80-83%, selectivity to linear dimers 93,6-96, 3%

Authors [V.P. Talzy, V.P. Doronin, T.P. Sorokina. ZhPKh, 2000, v.13, No. 5, p.787] dimerized α-methylstyrene on zeolite Y in methylene chloride at 25–40 ° C. The conversion of α-methylstyrene is 98.4-99.9 wt.%, The selectivity of the formation of linear dimers reaches 76.1-87.0%.

The patents provide methods for producing linear solvent-free α-methylstyrene dimers in the presence of HNaY zeolites [RF Patents No. 2189963, 2189964, 2313511] Beta [RF Patent No. 2322429], ZSM-12 [RF Patent No. 2312095].

For the synthesis of the cyclic dimer of α-methylstyrene 1,1,3-trimethyl-3-phenylindane (CDMS), mordenite and CaX type zeolites were used in a solvent medium — nitrobenzene or nitromethane [A.S. USSR No. 829606. 1979, BI 1981, No. 18]. The solvent content is 41-45 vol.%, The catalyst content is 18-19 wt.% Per charge (or 35-40% of the catalyst per α-methyl styrene); the reaction temperature is 80 ° C, the time is 2-2.5 hours. The yield of TMPI leaves 99.0 wt.%. The conversion of α-methylstyrene is not indicated, but since the description says that upon the isolation of TMPI, unreacted α-methylstyrene is distilled off, we can conclude that the monomer is not completely converted.

A known method for producing CDMS, carried out by dimerization of α-methylstyrene in the presence of a zeolite-containing cracking catalyst C-10 in an amount of 5-50 wt.% At a temperature of 60-150 ° C. The conversion of α-methylstyrene reaches 100 wt.%, The yield of TMPI is 92-98.8% [RF Patent 2223937]. Equally successfully, CDMS can be obtained in the presence of zeolite Beta [RF Patent 2327969].

Homodimerization of styrene proceeds with the formation of linear (LDS 2a) and cyclic dimers (CDS 2b, c)

Reaction Scheme

It was proposed to obtain a linear styrene dimer (trans-1,3-diphenylbutene-1) by dimerizing styrene in the presence of HY zeolite with a 10% degree of ion exchange, which was heat-treated at 400 ° C for 2 hours under vacuum. The reaction was carried out in an argon atmosphere in a solvent at a ratio of solvent: styrene = 50: 1 (vol.), The amount of catalyst was 55.5 wt.%. The linear dimer yield is 81% [K.B. John, J.L. Lim, J.K. Kochi. J. Mol. Catal. 1989, 52, p. 375-386].

The use of zeolite H-ZSM-12 allows to obtain linear styrene dimers with a selectivity of 68-75% in the presence of nonane with the ratio styrene: solvent = 1: 2-4 (vol.) [RF Patent No. 2349567] or with similar selectivity in the absence of solvent [ RF patent No. 2349568].

To synthesize cyclic styrene dimers of cis- and trans-1-methyl-3-phenylindanes (CDS), it was proposed to dimerize styrene in the presence of phosphoric acid [British Patent 1343 445], phosphoric acid on carbon [B.B. Corson, Ju. Dorsky, J.E. Nickels. J. Org. Chem. 1954, v.9, p.17-26], H-Nafion cation exchange resin [Hasegawa H., Higashimura T. Polim. J., 1979, 11, p. 737].

A known method of producing a cyclic styrene dimer in the presence of Beta zeolite. The reaction is carried out in a solvent CCl ₄ , the amount of which is from 227 to 454 volume parts per 1 vol. part of styrene. The catalyst is used in an amount of 500-1000 wt.% Based on styrene. The reaction temperature is 72 ° C, the time is 3 hours. The selectivity of the formation of a cyclic dimer is 84-90% with a styrene conversion of 95 wt.% [Benito A., Corma A., Garcia H. Appl. Catal. A: General. 1994, 116, p. 127-135].

In contrast to the widely studied homodimerization of styrene and α-methylstyrene, their combined dimerization has been little studied.

The joint oligomerization of styrene with α-methylstyrene under the action of phosphoric acid to obtain a mixture of cyclic homo- and codimers is described [R.N. Volkov, Yu.S. Tsybin, V.V. Kuzenkov. Petrochemistry, 1970, vol. X, No. 4, p. 541-545]. The reaction was carried out by adding 150 g of a mixture of monomers to 150 ml of evaporated phosphoric acid, gradually raising the temperature from 130 to 155 ° C for 3 hours. The yield of dimers was 80% at a molar ratio of styrene: α-methylstyrene = 1: 1. As a part of the dimers, a cyclic dimer of α-methylstyrene (CDMS) is formed; cyclic styrene dimers (VAT); two cyclic co-dimers (CDC) - 1,1-dimethyl-3-phenylindane and 1,3-dimethyl-3-phenylindane.

The disadvantages of this method include the use of a large amount of an aggressive, corrosive reagent - phosphoric acid, the complexity of its separation from the reaction products (the need for neutralization, washing, drying of the organic part before distillation), the appearance of a large number of effluents. In addition, the reaction products are only cyclic homo- and co-dimers.

The objective of the present invention is to develop a low-stage, environmentally friendly method for the joint oligomerization of styrene and α-methylstyrene.

The solution of this problem is achieved by the fact that the method of obtaining a mixture of homo- and codimers of styrene and α-methylstyrene is carried out by the interaction of styrene and α-methylstyrene in the presence of ZSM-12 zeolite. The reaction is carried out in chlorobenzene with a molar ratio of styrene: α-methylstyrene = 1: 1, a temperature of 80-130 ° C and a catalyst amount of 5-30 wt.% (Based on the mixture of monomers). The initial concentration of monomers in chlorobenzene is 2-8 mol / L.

Zeolite ZSM-12 is used in the hydrogen form of H-ZSM-12.

The conversion of styrene and α-methylstyrene is 96.2-100 wt.%. The yield of dimers in the presence of zeolite ZSM-12 reaches 84 wt.%. As a part of dimers, cyclic and linear dimers of styrene (CDS and LDS), α-methyl styrene (CDMS and LDMS), as well as cyclic codimer (CDC) - 1,1-dimethyl-3-phenylindane (6) and linear co-dimers - trans 3-methyl-1,3-diphenylbut-1-ene (3), 2,4-diphenyl-pent-2-ene (4), 2,4-diphenyl-pent-1-ene (5). The content of codimers in the dimeric fraction reaches 50.2 wt.%. The ratio of cyclic codimer: linear codimer is 0.8-1.2: 1. In addition to dimers, oligomers are formed with the number of monomer units n = 3-5.

Scheme of co-polymerization of styrene and α-methylstyrene:

A comparative analysis of the proposed solution with the prototype shows that the claimed method differs from the prototype in that in the process of co-polymerization of styrene and α-methylstyrene, ZSM-12 zeolite is used as a catalyst. The codimerization process is carried out in the presence of 5-30 wt.% Catalyst at a temperature of 80-130 ° C. The conversion of styrene and α-methylstyrene reaches 100 wt.%, And the yield of dimers, which include homo- and co-dimers of these vinylarenes, is 84%.

The zeolite catalyst ZSM-12 is easily separated by filtration. It can be used repeatedly without loss of activity.

The proposed method is as follows. The zeolite ZSM-12 catalyst was synthesized in the H-form at Angarsk Plant of Catalysts and Organic Synthesis OJSC according to DC 04-213030-008-2004. The molar ratio of SiO ₂ / Al ₂ O ₃ = 34, the degree of crystallinity of 96%. Before the experiments, the catalyst is calcined in an air atmosphere of about 540 ° C for 4 hours.

Co-oligomerization was carried out in a batchwise thermostated reactor, in the presence of 5-30 wt.% Catalyst, at 100-130 ° C in chlorobenzene medium. The reaction mass is stirred at the reaction temperature for a certain time. After the reaction, the reaction mass was separated from the catalyst by filtration. The degree of conversion of the starting vinylarenes and the composition of the dimer fraction were analyzed by gas-liquid chromatography. The composition of the resulting oligomers was analyzed by high performance liquid chromatography. For calibration, dimers and trimers were isolated by vacuum distillation.

GLC analysis was carried out on a HRGS 5300 Mega Series chromatograph (Carlo Erba) with a flame ionization detector (25 m capillary column, SE-30 phase, heating programming from 50 to 280 ° C with a rise rate of 8 ° C / min, temperature detector 250 ° C, evaporator temperature 300 ° C, carrier gas - helium, 30 ml / min). HPLC analysis was performed on an HP-1090 chromatograph with a refractometric detector and a Plgel 100Å polystyrene column, eluent-toluene, toluene feed rate 0.8 ml / min, tape speed 1.5 cm ^-1 .

The proposed method is illustrated by the following examples (see drawing and tables. 1 and 2).

EXAMPLE 1. A mixture of 5.2 g (0.05 mol) of styrene and 5.9 g (0.05 mol) of α-methylstyrene in 25 ml of chlorobenzene was placed in a glass heated reactor with a stirrer, reflux condenser and thermometer. At 120 ° C, 0.55 g of ZSM-12 zeolite was added and stirred at this temperature for 5 hours. After cooling, the catalyst was filtered off from the reaction mixture, then the solvent and unreacted vinylarenes were removed under reduced pressure. Received 10.1 g of oligomers of the composition, wt.%: Dimers - 71.2; oligomers n≥3 - 28.8. The composition of the dimers contains, wt.%: Cyclic co-dimers (CSD - 20.2) and linear (LSD - 21.9); styrene dimers (CDS - 3.9 and LDS - 13.1), α-methylstyrene dimers (CDMS - 7.2 and LDMS - 33.7).

Trans-3-methyl-1,3-diphenylbut-1-ene (3). NMR spectrum. ¹ H (δ, ppm); 1.70 (s. CH ₃ ; 6H); 6.60-6.65 (m, CH = CH; 2H); ¹³ C NMR spectrum (δ, ppm):

28.89 (CH ₃ ); 40.94 (CH); 126.09 (= CH); 140.30 (= CH). Mass spectrum, m / z: 222; Kovacs index 1820.

2.4-Diphenyl-pent-2-ene (4). ¹ H NMR Spectrum (δ, ppm): 1.60 (d. CH ₃ ; 3H); 2.26 (s; CH ₃ ; 3H); 4.03 (m, CH; 1H); 6.11 (d, = CH; 1H. ¹³ C NMR spectrum (δ, ppm): 16.26 (CH ₃ ); 22.61 (CH ₃ ); 38.47 (CH); 133.59 ( HC =); 143.83 (= C); Mass spectrum, m / z: 222; Kovacs index 1830.

2,4-Diphenylpent-1-ene (5). Mass spectrum, m / z: 222; Kovacs index 1746.

1,1-Dimethyl-3-phenylindane (6). ¹ H NMR Spectrum (δ, ppm): 1.36 (s, 3H, CH ₃ ), 1.40 (s, 3H, CH ₃ ), 1.79 (m, 1H, CH ₂ ); 2.06 (m, 1H, CH ₂ ); 4.43 (t, 1H, CH). ¹³ C NMR spectrum (δ, ppm): 29.70 (-CH ₃ ); 29.10 (-CH ₃ ); 46.64 (-C (CH ₃ ) ₂ ); 49.04 (CPh); 52.79 (-CH ₂ -). Mass spectrum, m / z: 222; Kovacs index 1713.

Examples 2-7 are shown in table. 1, 2 analogously to example 1.

Claims (2)

1. A method for the joint production of cyclic and linear homo- and codimers of styrene and α-methylstyrene by codimerizing monomers in the presence of an acid catalyst, characterized in that 5–30 wt% zeolite H-ZSM-12 is used as a catalyst and the reaction is carried out in chlorobenzene at a temperature of 80-130 ° C. 2. The method according to claim 1, characterized in that the concentration of the mixture of styrene and α-methylstyrene in chlorobenzene is 2-8 mol / L.

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