RU2470707C1 - Catalyst for trimerisation of ethylene to 1-hexene, ligand for producing catalyst, method of producing catalyst and method of producing ligand - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing an ethylene trimerisation catalyst ligand. Described is a method of producing a ligand of a catalyst for trimerisation of ethylene to 1-hexene of general formula:

where R is alkyl, R_1-7 is hydrogen and/or alkyl, involving a reaction for synthesis of 2-(alkylthio)alkylamine and 2-(alkylthio)alkylketone or alkylthioalkanal, where the alkyl in the alkylthio substitute is octyl, and the alkyl in alkylamine and alkylketone is CH₃, C₂H₅, in the presence of titanium tetraisopropoxide in toluene medium at temperature of 50-80°C, with subsequent addition of ethanol and tetrahydrofuran, cooling the obtained solution to 2-0°C, subsequent addition of sodium borohydride and hydrochloric acid using the following formula:

wherein alkylthioalkanal is selected from a group comprising: 2-(octylthio)-2-methylpropanal, 2-(octylthio)butanal, 2-(octylthio)pentanal, 2-(octylthio)hexanal, 2-(octylthio)heptanal, 2-(octylthio)octanal, 2-(octylthio)nonanal, 2-(octylthio)decanal.

EFFECT: method provides toxic and environmental safety when producing the ligands.

1 tbl, 14 ex

Description

The invention relates to a technology for producing bis (2-alkylthio-ethyl) amine ligands of catalysts for the trimerization of ethylene into 1-hexene.

1-Hexene is an important commercial intermediate used as a comonomer in the production of linear low density polyethylene.

A known technology for producing homogeneous catalytic systems for the synthesis of 1-hexene and 1-octene (RF Patent No. 2352389).

A disadvantage of the known technology is that when using products of this technology, butene, higher oligomers and polyethylene are formed along with α-olefins. The yield of the target product in these processes is limited, since α-olefins are formed according to the Schulz-Flory distribution and an additional stage of product separation is required or a significant percentage of 1-decene or other α-olefins is present among the reaction products.

Known ligand for a catalyst for the trimerization of ethylene to 1-hexene based on chromium compounds (International publication WO 03/053890) and a catalyst for the trimerization of ethylene to 1-hexene, consisting of a complex of chromium with a bis (2-alkylthio-ethyl) amine ligand and an activator - methylalumoxane, as well as a method for producing a ligand, the implementation of which uses bis (2-chloroethyl) amine or its hydrochloride and alkyl mercaptans (International publication WO 03/053891).

The main disadvantage of this catalyst with the specified ligand and the method for its preparation is the need to use the starting compounds - bis (2-chloroethyl) amine or its hydrochloride, which are poisonous substances of skin-boiling action, as well as alkyl mercaptans, which, in the case of an alkyl substituent with a chain length 6 carbon atoms and less, are highly toxic environmentally harmful compounds with an unpleasant odor. Another disadvantage of this catalyst is the fact that the longer the hydrocarbon chain of the substituents at the sulfur atoms in the SNS ligand of the complexes, the less these complexes are soluble in the reaction medium, which makes the system heterogeneous and leads to an increase in the amount of polymer, reducing the yield of the target product.

The objective of the invention is to develop a technology for producing bis (2-alkylthio-ethyl) amine ligands from non-toxic and easy-to-store raw materials for the further preparation of catalysts for the highly selective trimerization of ethylene into 1-hexene.

The technical result consists in ensuring the production of ligands from the structure, toxic and environmental safety in the production and use of ligands with a branched structure.

The technical result is achieved by the fact that the ligand of the General formula:

where R is alkyl, R ^1-7 is hydrogen and / or alkyl, obtained by the synthesis of 2- (alkylthio) alkylamine and 2- (alkylthio) alkylketone or alkylthioalkanal, where alkyl in the alkylthio substituent is octyl and alkyl in alkylamine and alkyl ketone - CH ₃ , C ₂ H ₅ , in the presence of titanium tetraisopropoxide in toluene at a temperature of 50-80 ° C followed by the addition of ethanol and tetrahydrofuran, cooling the resulting solution to 2-0 ° C, sequentially adding sodium borohydride and hydrochloric acid following formula:

This technology for the production of these ligands is environmentally friendly and highly selective for the resulting product, while ensuring the branched structure of the ligand

It was found that chromium complexes with branched SNS ligands have better solubility in aromatic and saturated hydrocarbons compared with the known solutions, which leads to a decrease in the amount of by-product polymer and increases the selectivity of the catalyst for 1-hexene. When testing the branched ligand obtained by the proposed technology, a catalyst was synthesized whose 1-hexene selectivity reaches 97% with a productivity exceeding 30,000 g / g (Cr) * h and a polymer selectivity of less than 0.5%.

A key component of the catalyst for the trimerization of ethylene to 1-hexene is the branched bis (2-alkylthio-ethyl) amine ligand of the general formula: RSC (R ¹ , R ² ) C (R ³ , R ⁴ ) N (H) C (R ⁵ , R ⁶ ) C (R ⁷ , R ⁸ ) SR, where R is alkyl; R ^1-7 is hydrogen and / or alkyl. The chromium complex with the SNS ligand can be obtained directly from the ligand and the chromium source.

The source of chromium can be simple inorganic or organic chromium salts, which are halides, acetylacetonates, carboxylates, oxides, nitrates, sulfates, etc. They may also include coordination and organometallic complexes, for example, a complex of chromium trichloride with tetrahydrofuran.

The catalytic trimerization of ethylene is carried out in an autoclave using a magnetic stirrer at an ethylene pressure of 5-45 bar. Increasing pressure increases productivity. The preferred reaction temperature is in the range from 50 ° C to 120 ° C. An increase in temperature contributes to a greater formation of oligomerization products, but too much heating reduces the performance of the system and decomposes the catalyst. Therefore, the optimal ethylene trimerization temperature is selected individually for each complex because of the difference in their stability. Too high a temperature reduces the solubility of ethylene in the reaction medium.

Productivity when using a catalyst with a ligand obtained by the technology according to this invention exceeds 30,000 g / g (Cr) * h with a selectivity of C ₆ fraction of 96% and higher. The content of 1-hexene in the fraction exceeds 99.5%. The amount of polymer at the same process temperature varies slightly for complexes with different ligands, the polymer selectivity for the best catalysts does not exceed 0.5%. The presence in the ligand in ethyl bridges of at least one dialkyl-substituted carbon decreases the activity of the catalytic system (reduces the amount of α-olefins formed) and simultaneously leads to an increase in selectivity for the resulting polymer.

The synthesis of bis (2-alkylthio-ethyl) amine ligands having one or more substituents in the ethyl bridges of the SNS framework was carried out according to the following scheme:

where R is alkyl, R ^1-7 is H and / or alkyl.

The method of obtaining ligands is illustrated by the following examples.

Example 1

To a solution of 2.3 mmol of [2- (octylthio) -2,2-dimethylethyl] amine and 2.4 mmol of 2- (octylthio) -2-methylpropanal in 2 ml of toluene, 3.5 mmol (1 g) of titanium tetraisopropoxide is added. Stir the mixture for 18 hours at 80 ° C. The reaction is monitored by TLC (eluent - ethyl acetate: hexane = 1: 5). Evaporate the solution to half the volume, add 7 ml of ethanol and 7 ml of tetrahydrofuran, cool to 0 ° C, add 4.17 mmol (0.15 g) of sodium borohydride, mix for 30 minutes. Then the reaction mass is warmed to room temperature and filtered. The filtrate was again cooled to 0 ° C., concentrated hydrochloric acid was added dropwise until gas evolution ceased. The cooling is stopped, and then the mixture is further stirred at room temperature for 2 hours, then the solution is evaporated to dryness. To purify the obtained amine, 15 ml of diethyl ether and 5 ml of hexane were added to the residue, and the mixture was allowed to crystallize at -20 ° C. The precipitated hydrochloride precipitate is filtered off and dried. Pure amine is obtained by treating a benzene hydrochloride solution with an aqueous solution of a base. The amine remains in the organic phase, its solution is evaporated and dried. The yield of bis- [2- (octylthio) -2,2-dimethylethyl] amine is 80%. Spectrum ¹ H NMR (300 MHz, CDCl ₃ ) δH, ppm: 0.89 (6H, t, CH ₃ ), 1.28 (16H, m, CH ₂ (S-Alk)), 1.39 (4H, m, CH ₂ CH ₃ ), 1.49 (12H, s, CCH ₃ ), 1.59 (4H, m, CH ₂ CH ₂ S), 2.52 (4H, t, CH ₂ S) 3.08 (4H, m, CH ₂ N).

Example 2

The reaction is carried out as in example 1, but using 2- (octylthio) propan-2-amine and 1- (octylthio) acetone. The yield of bis [2- (octylthio) -1- (methyl) ethyl] amine is 53%.

Spectrum ¹ H NMR (300 MHz, CDCl ₃ ) δH, ppm: 0.89 (6H, t, CH ₃ ), 1.10 (6H, d, CH ₃ ), 1.28 (16H, m, CH ₂ (S-Alk)), 1.39 (4H, m, CH ₂ CH ₃ ), 1.62 (4H, m, CH ₂ CH ₂ S), 2.23 (4H, dd, SCH ₂ CH) 2.52 (4H, t, CH ₂ S); 3.50 (2H, m, CHN).

Example 3

The reaction is carried out as in example 1, but using [2- (octylthio) butyl] amine and 2- (octylthio) butanal. The yield of bis [2- (octylthio) butyl] amine is 77%.

Spectrum ¹ H NMR (300 MHz, CDCl ₃ ) δH, ppm (S-Alk is a substituent at the sulfur atom): 0.88 (6H, t, CH ₃ (S-Alk)), 1.15 (6H, t, CHCH ₂ CH ₃ ), 1.28 (16H, m, CH ₂ (S-Alk)), 1.33 (4H, m, CH ₂ CH ₂ CH ₃ (S-Alk)), 1.55 (4H, m, CH ₂ CH ₂ S (S-Alk)), 1.60 (4H, m, CHCH ₂ CH ₃ ), 2.60 (4H, dd, CH ₂ N), 2.70 (4H, dt, CH ₂ S), 2.80 (2H, m, CH) .

Example 4

To a solution of 2.3 mmol of [2- (octylthio) -1,1-dimethylethyl] amine and 2.4 mmol of 2- (octylthio) -2-methylpropanal in 2 ml of toluene, 3.5 mmol (1 g) of tetraisopropoxyditanium are added. Stir the mixture for 18 hours at 50 ° C. The reaction is monitored by TLC (eluent - ethyl acetate: hexane - 1: 5). Evaporate the solution to half the volume, add 7 ml of ethanol and 7 ml of tetrahydrofuran, cool to 2 ° C, add 4.17 mmol (0.15 g) of sodium borohydride, mix for 30 minutes. Then the reaction mass is warmed to room temperature and filtered. The filtrate was again cooled to 2 ° C, concentrated hydrochloric acid was added dropwise until gas evolution ceased. The cooling is stopped, and then the mixture is further stirred at room temperature for 2 hours, then the solution is evaporated to dryness. To purify the obtained amine, 15 ml of diethyl ether and 5 ml of hexane were added to the residue, and the mixture was allowed to crystallize at -20 ° C. The precipitated hydrochloride precipitate is filtered off and dried. Pure amine is obtained by treating a benzene hydrochloride solution with an aqueous solution of a base. The amine remains in the organic phase, its solution is evaporated and dried.

The yield of 2-octylthio-1,1- (dimethyl) ethyl- [2- (octylthio) -2-methylpropyl] amine is 71%.

¹ H NMR spectrum (300 MHz, CDCl ₃ ) δH, ppm: 0.88 (6H, t, CH ₃ (S-Alk)), 1.16 (6H, s, (CH ₃ ) ₂ CNH) 1.35 (20H, m, CH ₂ (S-Alk)), 1.45 (6H, s, (CH ₃ ) ₂ CHS, 1.48 (2H, s, CCH ₂ S), 1.60 ( 4H, m, CH ₂ CH ₂ S), 2.57 (4H, dt, CH ₂ S (S-Alk)), 3.21 (2H, s, CH ₂ NH).

Example 5

The reaction is carried out as in example 4, but using [2- (octylthio) -1,1- (dimethyl) ethyl] amine and 2- (octylthio) butanal. The yield of [2-octylthio-1,1- (dimethyl) ethyl] - [2- (octylthio) butyl] amine is 40%.

¹ H NMR spectrum (300 MHz, CDCl ₃ ) δH, ppm: 0.88 (6H, t, CH ₃ (S-Alk)), 1.00 (3H, t, CH ₃ CH ₂ CH), 1.16 (6H, s, (CH ₃ ) ₂ CNH), 1.26 (16H, m, CH ₂ (S-Alk)), 1.35 (4H, br.m, CH ₂ CH ₃ (S- Alk)), 1.51 (2H + 4H, m + m, CH ₂ CH ₂ S + CHCH ₂ CH ₃ ), 2.50 (2H + 4H + 1H, m + m + m, CH ₂ S + CH ₂ S (S-Alk) + CH), 2.62 (2H, br s, CHH'NH).

Example 6

The reaction is carried out as in example 4, but using 1- (octylthio) propan-2-amine and 2- (octylthio) butanal. The yield of [2- (octylthio) butyl] [2- (octylthio) -1- (methyl) ethyl] amine is 70%.

¹ H NMR spectrum (300 MHz, CDCl ₃ ) δH, ppm: 0.88 (6H, t, CH ₃ (S-Alk)), 1.01 (3H, t, CH ₃ CH ₂ CH), 1.15 (3H, d, CH ₃ CH), 1.28 (16H, broad m, CH ₂ (S8-Alk)), 1.39 (4H, m, CH ₂ CH ₃ (S-Alk)) 1.58 (4H, m, CH ₂ CH ₂ S (S-Alk), 1.67 (2H, m, CH ₃ CH ₂ CH), 2.48-2.55 (2H + 4H, m + m SCHH'CH + CHH'S), 2.58 (1H, m, CHS).

Example 7

To a solution of 2.3 mmol of octylthioethylamine and 2.4 mmol of 2- (octylthio) butan-2-one in 2 ml of toluene, 3.5 mmol (1 g) of titanium tetraisopropoxide is added. Stir the mixture for 18 hours at 60 ° C. The reaction is monitored by TLC (eluent - ethyl acetate: hexane - 1: 5). Evaporate the solution to half the volume, add 7 ml of ethanol and 7 ml of tetrahydrofuran, cool to 1 ° C, add 4.17 mmol (0.15 g) of sodium borohydride, mix for 30 minutes. Then the reaction mass is warmed to room temperature and filtered. The filtrate is again cooled to 1 ° C, concentrated hydrochloric acid is added dropwise until gas evolution ceases. The cooling is stopped, and then the mixture is further stirred at room temperature for 2 hours, then the solution is evaporated to dryness. To purify the obtained amine, 15 ml of diethyl ether and 5 ml of hexane were added to the residue, and the mixture was allowed to crystallize at -20 ° C. The precipitated hydrochloride precipitate is filtered off and dried. Pure amine is obtained by treating a benzene hydrochloride solution with an aqueous solution of a base. The amine remains in the organic phase, its solution is evaporated and dried.

The yield of [2- (octylthio) butyl] [2- (octylthio) ethyl] amine is 94%.

¹ H NMR spectrum (300 MHz, CDCl ₃ ) δH, ppm: 0.88 (6H, t, CH ₃ (S-Alk)), 1.00 (3H, t, CH ₃ CH ₂ CH), 1.26 (16H, br.s, CH ₂ (S-Alk)), 1.35 (4H, m, CH ₂ CH ₃ (S-Alk)), 1.55 (4H, m, CH ₂ CH ₂ S (S-Alk)), 1.65 (2H, m, CH ₃ CHH'CH), 2.50 (2H + 2H, t + m, NHCH ₂ CH + NHCH ₂ CHH'S), 2.65 (4H, m, CHH'S (S-Alk)), 2.75-2.79 (1H + 2H, m + m, SCH + CHCHH'NH).

Example 8

The reaction is carried out as in example 7, but using octylthioethylamine and 1- (octylthio) acetone. The yield of [2- (octylthio) ethyl] [2- (octylthio) -1- (methyl) ethyl] amine is 90%.

¹ H NMR spectrum (300 MHz, CDCl ₃ ) δH, ppm: 0.88 (6H, t, CH ₃ (S-Alk)), 1.11 (3H, d, CH ₃ CH), 1, 27 (16H, br.m, CH ₂ (S-Alk)), 1.37 (4H, m, CH ₂ CH ₃ (S-Alk)), 1.58 (4H, m, CH ₂ CH ₂ S ( S-Alk), 2.45-2.52 (2H + 2H, m + t, CHCHH'S + CH ₂ CH ₂ S), 2.64 (4H, t, CH ₂ S (S-Alk)), 2, 71-2.87 (2H + 1H, m + m, CH ₂ N + CH).

Example 9

The reaction is carried out as in example 7, but using octylthioethylamine and 2- (octylthio) pentanal. The yield of [2- (octylthio) ethyl] [2- (octylthio) -2-propylethyl] amine is 42%.

¹ H NMR spectrum (300 MHz, CDCl ₃ ) δH, ppm: 0.76 (3H, t, CH ₃ CH ₂ CH ₂ CH), 0.88 (6H, t, CH ₃ (S-Alk) ), 1.26 (18H, br.s, CH ₂ (S-Alk) + CHCH ₂ CH ₂ CH ₃ ), 1.35 (4H + 2H, m + m, CH ₂ CH ₃ (S-Alk) + CH ₂ CH ₂ CH ₃ ), 1.55 (4H, m, CH ₂ CH ₂ S (S-Alk)), 2.50 (2H + 2H, t + m, NCH ₂ CH + NHCH ₂ CHH'S), 2 65 (4H, m, CHH'S (S-Alk)), 2.75-2.79 (1H + 2H, m + m, SCH + CHCHH'NH).

Example 10

The reaction is carried out as in example 7, but using octylthioethylamine and 2- (octylthio) hexanal. The yield of [2- (octylthio) ethyl] [2- (octylthio) -2-butylethyl] amine is 45%.

Spectrum ¹ H NMR (300 MHz, CDCl ₃ ) δH, ppm: 0.88 (9H, t, CH ₃ (S-Alk) + CH ₃ CH ₂ CH ₂ CH ₂ CH ₂ CH), 1.26 (18H , br.s.CH ₂ (S-Alk) + CHCH ₂ CH ₂ CH ₂ CH ₃ ), 1.35 (4H, m, CH ₂ CH ₃ (S-Alk)), 1.55 (4H + 2H, m + m, CH ₂ CH ₂ S (S-Alk) + CHCH ₂ CH ₂ CH ₂ CH ₃ ), 1.65 (2H, m, CH ₃ CH ₂ CH ₂ CHH'CH), 2.50 (2H + 2H, t + m, NHCH ₂ CH + NHCH ₂ CHH'S), 2.65 (4H, m, CHH'S (S-Alk)), 2.75-2.79 (1H + 2H, m + m, SCH + CHCHHH 'NH).

Example 11

The reaction is carried out as in example 7, but using octylthioethylamine and 2- (octylthio) heptanal. The yield of [2- (octylthio) ethyl] [2- (octylthio) -2-pentylethyl] amine is 37%.

¹ H NMR spectrum (300 MHz, CDCl ₃ ) δH, ppm: 0.88 (9H, t, CH ₃ (S-Alk) + CH ₃ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH), 1.26 (18H, br.s, CH ₂ (S-Alk) + CHS ₂ CH ₂ CH ₂ CH ₂ CH ₃ ), 1.35 (4H, m, CH ₂ CH ₃ (S-Alk) + CH ₃ CH ₂ CH ₂ CH ₂ CH ₂ CH), 1.55 (4H + 2H, m + m, CH ₂ CH ₂ S (S-Alk) + CHCH ₂ CH ₂ CH ₂ CH ₂ CH ₃ ), 1.65 (2H, m , CH ₃ CH ₂ CH ₂ CH ₂ CHH'CH), 2.50 (2H + 2H, t + m, NHCH ₂ CH + NHCH ₂ CHH'S), 2.65 (4H, m, CHH'S (S-Alk)) 2.75-2.79 (1H + 2H, m + m, SCH + CHCHHH'NH).

Example 12

To a solution of 2.3 mmol of octylthioethylamine and 2.4 mmol of 2- (octylthio) octanal in 2 ml of toluene, 3.5 mmol (1 g) of titanium tetraisopropoxide is added. Stir the mixture for 18 hours at 70 ° C. The reaction is monitored by TLC (eluent - ethyl acetate: hexane -1: 5). Evaporate the solution to half the volume, add 7 ml of ethanol and 7 ml of tetrahydrofuran, cool to 1.5 ° C, add 4.17 mmol (0.15 g) of sodium borohydride, mix for 30 minutes. Then the reaction mass is warmed to room temperature and filtered. The filtrate was again cooled to 1.5 ° C., concentrated hydrochloric acid was added dropwise until gas evolution ceased. The cooling is stopped, and then the mixture is further stirred at room temperature for 2 hours, then the solution is evaporated to dryness. To purify the obtained amine, 15 ml of diethyl ether and 5 ml of hexane were added to the residue, and the mixture was allowed to crystallize at -20 ° C. The precipitated hydrochloride precipitate is filtered off and dried. Pure amine is obtained by treating a benzene hydrochloride solution with an aqueous solution of a base. The amine remains in the organic phase, its solution is evaporated and dried.

The yield of [2- (octylthio) ethyl] [2- (octylthio) -2-hexylethyl] amine is 41%.

Spectrum ¹ H NMR (300 MHz, CDCl ₃ ) δH, ppm: 0.88 (9H, t, CH ₃ (S-Alk) + CH ₃ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH), 1 26 (20H, br.s., CH ₂ (S-Alk) + CHCH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₃ ), 1.35 (4H, m, CH ₂ CH ₃ (S-Alk) + CH ₃ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH), 1.55 (4H + 2H, m + m, CH ₂ CH ₂ S (S-Alk) + CHCH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₃ ) 1.65 (2H, m, CH ₃ CH ₂ CH ₂ CH ₂ CH ₂ CHH'CH), 2.50 (2H + 2H, t + m, NCH ₂ CH + NHCH ₂ CHH'S), 2.65 (4H m, CHH'S (S-Alk)), 2.75-2.79 (1H + 2H, m + m, SCH + CHCHH'NH).

Example 13

The reaction is carried out as in example 12, but using octylthioethylamine and 2- (octylthio) nonanal. The yield of [2- (butylthio) ethyl] [2- (butylthio) -2-heptylethyl] amine is 35%.

Spectrum ¹ H NMR (300 MHz, CDCl ₃ ) δH, ppm: 0.88 (9H, t, CH ₃ (S-Alk) + CH ₃ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH) , 1.26 (6H, br.s, CHCH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₃ ), 1.35 (4H + 2H, m, CH ₂ CH ₃ (S-Alk) + CH ₃ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH), 1.55 (4H + 2H, m + m, CH ₂ CH ₂ S (S-Alk) + CHCH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₃ ), 1.65 (2H, m, CH ₃ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CHH'CH), 2.50 (2H + 2H, t + m, NHCH ₂ CH + NHCH ₂ CHH'S), 2 65 (4H, m, CHH'S (S-Alk)), 2.75-2.79 (1H + 2H, m + m, SCH + CHCHH'NH).

Example 14

The reaction is carried out as in example 12, but using ethylthioethylamine and 2- (ethylthio) decanal. The yield of [2- (ethylthio) ethyl] [2- (ethylthio) -2-octylethyl] amine is 43%.

Spectrum ¹ H NMR (300 MHz, CDCl ₃ ) δH, ppm: 0.88 (9H, t, CH ₃ (S-Alk) + CH ₃ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH), 1.26 (8H, br.s, CHCH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₃ ), 1.35 (2H, m, CH ₃ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH), 1.55 (2H, m, CHCH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₃ ), 1.65 (2H, m, CH ₃ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CHH'CH), 2.50 (2H + 2H, t + m, NHCH ₂ CH + NHCH ₂ CHH'S), 2.65 (4H, m, CHH'S (S-Alk)), 2, 75-2.79 (1H + 2H, m + m, SCH + CHCHHH'NH).

The synthesis of chromium (III) complexes with bis (2-alkylthio-ethyl) amine ligands is carried out in toluene medium according to the following scheme:

where R is alkyl, R ^1-7 is hydrogen and / or alkyl, X is an acidoligand or a tetrahydrofuran complex with chlorine or bromine.

The ethylene trimerization catalyst is prepared as follows. To a suspension of 0.29 mmol of a compound of trivalent chromium with an acidoligand or a complex of tetrahydrofuran and chlorine in 4 ml of toluene, a solution of 0.29 mmol of the ligand from Examples 1-6 in 4 ml of toluene is added. The color of the solution turns green-blue. It is stirred for 45 minutes, then toluene is evaporated, 8 ml of hexane, 8 ml of diethyl ether are added and the solution is left with a precipitate overnight at a temperature of -20 ° С, the precipitate is filtered off the next day and dried in vacuum. The yield of catalyst is 95-98%.

Evaluation of the effectiveness of the catalysts was carried out in the following process of catalytic trimerization of ethylene.

The process of catalytic trimerization of ethylene is carried out in an autoclave using a magnetic stirrer at an ethylene pressure of 5-45 bar. The autoclave is preheated at 120 ° C for 1.5 hours in a stream of argon. Argon and ethylene are passed through a pre-drying and purification system, the solvent (toluene) is distilled over sodium, degassed and stored in argon atmosphere. 4/5 parts of the amount of solvent required for the reaction (20 ml) are charged into the autoclave in an argon stream and heated to the reaction temperature with stirring. The catalyst solution is prepared in a separate flask in a stream of argon, loading a portion of the chromium complex (8 μmol), then the remaining amount of solvent (5 ml) is added and stirred for about 20-30 minutes, of which at least 15 minutes with weak heating (50 ° C) . Then, a 10% solution of methylaluminoxane in toluene (2.61 mmol MAO) is added to the solution of the chromium complex, it is stirred for 2-3 minutes and introduced into the autoclave with stirring at the reaction temperature, then the ethylene is fed to the required pressure. Heat the autoclave to the desired temperature. The reaction time is 30-60 minutes. At the end of the reaction time, ethylene supply is stopped, the autoclave is cooled to 15 ° C, the pressure is slowly reduced, methanol (1.5 ml) and the internal standard (n-decane, 0.2 g) are introduced into the autoclave and stirred for 10 minutes. Then the autoclave is opened, the whole reaction mixture is poured into a flask, 10 ml of diluted 5% hydrochloric acid and 5 ml of toluene are added, stirred for 10 minutes, allowed to stand and a sample is taken from the organic layer for chromatographic analysis. Analysis of liquid samples containing C ₂ -C ₃₀ hydrocarbons is carried out on a chromatograph with a flame ionization detector and a capillary column. The contents of the flask continue to mix for 5 hours. Then the organic layer is separated, washed with water 5 times in 10 ml, the organic layer is finally separated. Then the polymer is filtered off, washed with ethanol (10 ml) and dried at 100 ° C for 2-3 days.

The results of the analysis of reaction products using catalysts with a ligand obtained by the technology of this invention are shown in the table.

As the results show, the use of such catalysts significantly increases the selectivity for the final product while maintaining high performance.

Claims (1)

The method of obtaining the ligand of the catalyst for the trimerization of ethylene in 1-hexene of the General formula

where R-alkyl, R ^1-7 is hydrogen and / or alkyl, including the synthesis of 2- (alkylthio) alkylamine and 2- (alkylthio) alkylketone or alkylthioalkanal, where alkyl in the alkylthio substituent is octyl and alkyl in alkylamine and alkyl ketone - CH ₃ , C ₂ H ₅ , in the presence of titanium tetraisopropoxide in toluene at a temperature of 50-80 ° C, followed by the addition of ethanol and tetrahydrofuran, cooling the resulting solution to 2-0 ° C, sequentially adding sodium borohydride and hydrochloric acid according to the following the formula:

,
the alkylthioalkanal being selected from the group: 2- (octylthio) -2-methylpropanal, 2- (octylthio) butanal, 2- (octylthio) pentanal, 2- (octylthio) hegsanal, 2- (octylthio) heptanal, 2- (octylthio) octanal, 2- (octylthio) nonanal, 2- (octylthio) decanal.