RU2384559C1 - Method of producing 1-alkoxy-1-phenylethanes - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing 1-alkoxy-1-phenylethanes of general formula C₆H₅CH(CH₃)OR (R=CH₃, C₂H₅, n-C₃H₇, n-C₄H₉, n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, n-C₈H₁₇), which have high thermal stability and can be used as plasticising agents in chlorine-containing polymers and can also be used as a catalyst component in olefin polymerisation and copolymerisation processes. The method involves reacting styrene and alcohols of normal structure ROH, where R is as given above, in the presence of a zeolite-containing catalyst obtained by moulding zeolite Y in H-shape with amorphous aluminium silicate with a kaoline structure in ratio of 70:30 (mass), with molar ratio styrene:alcohol = 1:1-3 and catalyst amount of 5-10 wt %.

EFFECT: high output of desired products.

16 ex, 1 tbl

Description

The invention relates to the field of organic chemistry, in particular to a method for producing 1-alkoxy-1-phenylethanes of the general formula I:

where R = CH ₃ , C ₂ H ₅ , n-C ₃ H ₇ , n-C ₄ H ₉ , n-C ₅ H ₁₁ n-C ₆ H ₁₃ , n-C ₇ H ₁₅ , n-C ₈ N ₁₇ .

Compounds ArCH (CH ₃ ) OR (where R, for example, an alkyl, alkenyl, aryl, alkaryl and cycloaliphatic group) have high thermal stability and can be used as plasticizing agents in chlorine-containing polymers [US Pat. US No. 2575444]. Esters I (where R = CH ₃ , C ₂ H ₅ ) are proposed to be used as a component of catalysts in the polymerization and co-oligomerization of olefins [Pat. US No. 4762898]. It has been found that 1-ethoxy-1-phenylethane is more effective than chlorobenzenes as an insecticide for protection against moths [US Pat. Japan No. 57062202].

In [H.C. Brown, J.T. Kurek, M.H. Rei, K.L. Thomson // J.Org.Chem. 1984. 49. 2551-2557; H.C. Brown, J.T. Kurek, M.H. Rei, K. L. Thomson // J. Org. Chem. 1985. 50. 1171-1174] describes the preparation of 1-alkoxy-1-phenylethanes by alkoxymercation-demercuration of styrene in ROH alcohols (where R = Me, Et, i-Pr, t-Bu). Alkoxymercuration is carried out with various mercury salts.

(Hg (OAc) ₂ , Hg (CF ₃ COO) ₂ , Hg (NO ₃ ) ₂ , etc.) at 22 ° С. Subsequent demercuration is carried out in situ with an alkaline solution of NaBH ₄ :

Styrene conversion is maximal in the case of interaction with methyl alcohol (up to 99%); with isopropyl and tert-butyl alcohols, the conversion of styrene is lower and amounts to 40-90%, in addition, along with ether, alcohol ArCH (CH ₃ ) OH is formed.

The disadvantages of this method are multi-stage, the use of highly toxic salts of mercury as a catalyst. In addition, the process is carried out using large amounts of alkali (NaOH), resulting in the formation of significant volumes of effluents.

In the patent [Pat. USA No. 2285818] describes the preparation of 1-alkoxy-1-phenylethanes by the interaction of styrene with alcohols in the presence of acids (H ₂ SO ₄ , HCl ₄ , ClCH ₂ COOH) in a solution of isopropylbenzene:

where R = CH ₃ , C ₂ H ₅ , iC ₃ H ₇ , n-C ₄ H ₉ .

The reaction is carried out at a temperature of from 50 to 150 ° C in an autoclave (in the case of methanol and ethanol) or in a flask. The concentration of the catalyst is not more than 5%, the reaction time is 6-10 hours. The complexity of this reaction is that in the presence of acid catalysts, styrene oligomerization proceeds at a high rate. The authors note that a significant amount of styrene oligomers is formed in parallel with the esters. To reduce the yield of oligomers, it is proposed to use a polymerization inhibitor, pyrogallol. The conversion of styrene is 50-90%, the yields of esters 60-80%.

The disadvantages of the method include: low yields of esters; the need for stages of neutralization of the acid catalyst, washing and drying the reaction mass; the use of a solvent that must be regenerated at the end of the reaction; long reaction time.

Closest to the proposed invention is described in [S.P. Verevkin, A. Heintz // J. Chem. Eng. Data. - 2001. - 46. - No. 4. - P.984-990] a method for producing alkyl-phenylethyl ethers by reacting styrene with alcohols of normal structure — methyl, ethyl, propyl, butyl — in the presence of an Amberlyst-15 cation exchange resin in the H form. The reaction was carried out in the liquid phase at temperatures of 70-150 ° C, the amount of catalyst was 10 wt.%. In experiments with the maximum yield of ether (77-87 mol%), the styrene conversion was 78-87 mol%.

The disadvantages of this method include the insufficiently high activity of the catalyst in the reaction for the production of styrene esters. In addition, the low thermal stability of cation exchange resins at elevated temperatures (120-150 ° C) is known.

An object of the present invention is to increase the yield of 1-alkoxy-1-phenylethanes.

This is achieved by the fact that the method of producing 1-alkoxy-1-phenylethanes of the formula C ₆ H ₅ CH (CH ₃ ) OR (R = CH ₃ , C ₂ H ₅ , n-C ₃ H ₇ , n-C ₄ H ₉ , n-С ₅ Н ₁₁ , n-С ₆ Н ₁₃ , n-С ₇ Н ₁₅ , nC ₈ H ₁₇ ) by the interaction of styrene with alcohols of normal structure ROH (R = СН ₃ , С ₂ Н ₅ , n-С ₃ Н ₇ , n-C ₄ H ₉ , n-C ₅ H ₁₁ , nC ₆ H ₁₃ , nC ₇ H ₁₅ , n-C ₈ H ₁₇ ) in the presence of acid catalysts is carried out according to the invention in the presence of a zeolite-containing catalyst obtained by molding zeolite Y in the H form with amorphous aluminosilicate with a kaolin structure in the ratio of 70:30 (mass). The reaction is carried out at a molar ratio of styrene: alcohol of 1: 1-3, a temperature of 80-120 ° C and a catalyst amount of 5-10 wt.% (Calculated on the reaction mixture).

After completion of the reaction, the catalyst was separated by filtration. It can be used repeatedly without loss of activity. The obtained 1-alkoxy-1-phenylethanes are isolated from the reaction mass by vacuum distillation.

A comparative analysis of the proposed solution with the prototype shows that the claimed method differs from the prototype in that the interaction of styrene with n-alcohols is carried out in the presence of a zeolite-containing catalyst obtained by molding zeolite Y in the H-form with amorphous aluminosilicate with a kaolin structure in the ratio of 70:30 (wt. .). The esterification process is carried out at a molar ratio of styrene: alcohol of 1: 1-3, a temperature of 80-120 ° C and an amount of catalyst of 5-10 wt.% (Calculated on the reaction mixture). The styrene conversion is 78.7-92.8 mol%, the selectivity of the formation of 1-alkoxy-1-phenylethanes is 90.1-100 mol%, and styrene dimers are 0-9.9 mol%.

Under these conditions, styrene oligomers either do not form at all, or are present in small amounts (not more than 9.9 mol%). The maximum degree of oligomerization of styrene (n) is 2. There are no trimers and higher molecular weight compounds.

It can be noted that despite the decrease in the concentration of the active component (zeolite Y) in the catalyst during its formation with amorphous aluminosilicate, the activity and selectivity of the catalyst not only do not decrease (compared to zeolite Y), but even increase.

The proposed method is as follows.

The zeolite-containing catalyst was prepared by molding zeolite Y in the H form with an amorphous aluminosilicate with a kaolin structure in the ratio of 70:30 (wt.). Samples of zeolite Y (molar ratio of SiO ₂ / Al ₂ O ₃ = 4.8; 5.1; 5.5) used to prepare the catalyst were synthesized at OAO Salavatnefteorgsintez. In addition, a sample of zeolite Y with SiO ₂ / Al ₂ O ₃ = 6.0 was synthesized according to the procedure described in [US Pat. 2090502 RF, 1997]. Samples of NaY by two (three) -fold decationation were transferred to the NH ₄ form, and then subsequent calcination at 540 ° C in the H form. The degree of exchange of Na ⁺ for H ⁺ was 80-97%. Before the experiments, the catalyst is calcined in an atmosphere of air at 540 ° C for 4 hours. The interaction of styrene with alcohols is carried out in thermostated metal autoclaves or glass reactors. Styrene and alcohol are loaded into the autoclave (flask) in a molar ratio of 1: 1-3, 5-10 wt.% Of the catalyst (per reaction mass). The reaction is carried out with constant stirring at a temperature of 80-120 ° C for 2-4 hours. After completion of the reaction, the catalyst is separated by filtration. The reaction mass is dispersed in vacuo. The reaction mass and products are analyzed by GLC on a HRGS 5300 Mega Series Carlo Erba chromatograph with a flame ionization detector (25 m capillary column, SE-30 phase, temperature programming from 50 to 280 ° С with a rise rate of 8 ° С / min, the temperature of the detector is 250 ° С, the temperature of the evaporator is 300 ° С, the carrier gas is helium, 30 ml / min).

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

EXAMPLE 1. 5.7 ml (0.05 mol) of styrene and 5.7 ml of 4.0 ml (0.10 mol) of methyl alcohol, 0.84 g of catalyst (molar ratio SiO ₂ / Al ₂ O ₃ are loaded into the autoclave in zeolite Y is 6.0). The autoclave is placed in a thermostat. The reaction is carried out with constant stirring at a temperature of 110 ° C for 3 hours. The reaction mass is filtered off from the catalyst and separated by vacuum distillation. Obtain 5.2 g of product I (R = CH ₃ ). The styrene conversion is 78.7 mol%, there are no styrene dimers, the selectivity for 1-methoxy-1-phenylethane is 100% (boiling point 78.6 ° C / 50 mmHg; ¹ H NMR spectrum (δ , ppm): 1.36 (d, 3, CH ₃ ), 3.18 (s, 3, OCH ₃ ), 4.17 (q, 1, CH), 7.3 (m, 5, ArH); ¹³ C NMR spectrum ( δ, ppm): 19.00 (С-10), 55.67 (С-9), 69.00 (С-7), 125.51-127.32 (С-2-6), 144.05 (С-1)).

EXAMPLE 2. 5.7 ml (0.05 mol) of styrene and 9.1 ml (0.10 mol) of butyl alcohol, 1.26 g of catalyst (molar ratio of SiO ₂ / Al ₂ O ₃ in zeolite Y, are charged into a thermostatic flask. is 6.0). The reaction is carried out with constant stirring at a temperature of 110 ° C for 2 hours. The reaction mass is filtered off from the catalyst and separated by vacuum distillation. 8.1 g of product I are obtained (R = n-C ₄ H ₉ ). The styrene conversion is 92.5 mol%, the selectivity for 1-butoxy-1-phenylethane is 96.3% (bp 95.1 ° С / 10 mm Hg; ¹ H NMR spectrum (δ, m etc.): 0.86 (t, 3, CH ₃ ), 1.33 (m, 2, CH ₂ ), 1.35 (t, 2, CH 2), 1.45 (d, 3, CH ₃ ), 3.42 (q, 2, OCH ₂ ), 4.30 (q, 1, CH), 7.3 (m, 5, ArH); ¹³ С NMR spectrum (δ, ppm): 13.78 (С-12), 18.90 (С-11), 21.15 (С-13), 32.65 (С-10), 69.75 (С-7), 72.86 (С-9), 24.19 (С-12), 124.97-127.04 (С-2-6), 143.03 (С-1 )).

EXAMPLES 3-4. Analogously to example 1. The conditions and results of the examples are presented in the table.

EXAMPLES 5-16. Analogously to example 2. The conditions and results of the examples are presented in the table.

Reaction of styrene with alcohols in the presence of a zeolite-containing catalyst Example Alcohol SiO ₂ / Al ₂ O ₃ Reaction Conditions The conversion of styrene, mol.% Selectivity,% [kt], wt.% styrene: alcohol, moth T, ° С τ, h ether styrene dimers 3 C ₂ H ₅ OH 6 10 1: 2 110 3 79.2 one hundred 0 four C ₃ H ₇ OH 6 10 1: 2 110 3 89.3 one hundred 0 5 C ₄ H ₉ OH 6 5 1: 2 110 3 91.6 96.5 3,5 6 C ₄ H ₉ OH 6 10 1: 1 110 3 92.0 96.2 3.8 7 C ₄ H ₉ OH 6 10 1: 3 110 3 92.7 96.3 3,7 8 C ₄ H ₉ OH 4.8 10 1: 2 110 3 89.0 96.1 3.9 9 C ₄ H ₉ OH 5.1 10 1: 2 110 3 91.2 96.4 3.6 10 C ₄ H ₉ OH 5.5 10 1: 2 110 3 91.7 96.4 3.6 eleven C ₄ H ₉ OH 6 5 1: 2 80 four 89.9 96.8 3.2 12 C ₄ H ₉ OH 6 5 1: 2 120 2 92.8 96.6 3.4 13 C ₅ H ₁₁ OH 6 10 1: 2 110 3 90.8 94.6 5,4 fourteen C ₆ H ₁₃ OH 6 10 1: 2.5 110 four 87.3 94.4 5,6 fifteen C ₇ H ₁₅ OH 6 5 1: 2.5 one hundred four 80.3 90.1 9.9 16 C ₈ H ₁₇ OH 6 5 1: 2.5 110 four 79.8 91.2 8.8

Claims (1)

The method of obtaining 1-alkoxy-1-phenylethanes of the formula I

where R = CH ₃ , C ₂ H ₅ , n-C ₃ H ₇ , n-C ₄ H ₉ , n-C ₅ H ₁₁ , n-C ₆ H ₁₃ , n-C ₇ H ₁₅ , n-C ₈ H ₁₇ ,
catalytic interaction of styrene with alcohols of normal structure ROH, where R is the same as described above at a temperature of 80-120 ° C, characterized in that the reaction is carried out in the presence of a zeolite-containing catalyst obtained by molding zeolite Y in the H form with amorphous aluminosilicate with the structure of kaolin in a ratio of 70:30 (wt.), with a molar ratio of styrene: alcohol = 1: 1-3 and the amount of catalyst 5-10 wt.%.