CS218784B1 - Process for preparing a low pressure olefin hydrogenation catalyst - Google Patents

Abstract

The invention falls into the field of organic technology - hydrocarbon processing, and specifically relates to a method for preparing a homogeneous catalyst based on bis(cyclopentadienyl)dichlorotitanium complex for low-pressure hydrogenation of olefins in an aromatic hydrocarbon environment. The essence of the invention lies in the fact that the bis(cyclopentadienyl)dichlorotitanium complex is reduced in the reaction mixture of hydrogenated olefins with sesqui-(2-methoxyethoxy) alanine in a molar ratio to bis(cyclopentadienyl)dichlorotitanium complex 7 to 9 ■ 1.

Description

The present invention relates to a process for preparing a bis (cyclopentadienyl) dichlorotitanium complex catalyst for the low pressure hydrogenation of oleifines.

The prior art process for the hydrogenation of unsaturated hydrocarbons is carried out as a heterogeneously catalyzed reaction with hydrogen at a temperature of 40 to 700 K and a pressure of 10 to 20 MPa. This process involves a number of energy-intensive operations (heating and cooling, compression and expansion of reactants), and precious metal compounds are the most commonly used catalysts. If pure reagents are not used during the reaction, deactivation and even poisoning of the catalysts occur. The yields of heterogeneous hydrogenation do not reach If110% and by prolonged reaction, by-products are formed under given pressure and temperature conditions.

Substantially greater yields of hydrogenation of unsaturated hydrocarbons are obtained by using a homogeneous catalyst. In hydrogenation of 1-hexene according to Art. aut. osv. No. 190,174 yielded 97% yield using the dichloro-bis catalyst (triethyl ₇ nickel phosphate nickel complex - lithium borohydride in tetrahydrofuran) High cost of reducing agent, difficult separation of hexane formed from tetrahydrofuran and that the method required the use of freshly distilled tetrahydrofuran without the water content prevented the expansion of this catalytic system.

These shortcomings will be remedied in stages. according to the invention, which is a process for preparing a catalyst based on bis (cyclopentadienyl) dichlorotitanium complex for the low pressure hydrogenation of olefins in an aromatic hydrocarbon environment. SUMMARY OF THE INVENTION The bis (cyclopentadienyl) dichlorotitanium complex in a hydrogenated olefin reaction mixture is reduced with sesqui (2-methoxyethoxylalanine in a molar ratio to the bis (cyclopentadienyl) dichlorotitanium complex of 7 to 9: 1).

Using a homogeneous catalyst prepared by the process of the present invention, a saturated hydrocarbon can be prepared in high yield by low pressure hydrogenation of an unsaturated hydrocarbon using a readily available and safe reducing agent. A solution of sesqui [1,2-methoxyethoxy ]lane can be prepared in a variety of aromatic hydrocarbons, making it possible to choose a suitable solvent for easier separation of the reaction mixture. It can also be prepared directly in the reaction mixture from sodium dihydrobis (2-methoxyethoxyaluminate) Up to 3: 1.1 Due to the low reaction temperature and hydrogen pressure, the cost of the hydrogenation plant is low, with a smaller amount of catalyst system hydrogenation at higher temperature and pressure, without the use of pre-dried hydrogen and olefin. The ratio of (bis (cyclopentadienyl) dichlorotitanium complex to hydrogenated hydrocarbon is chosen from 140 to 160: 1 (mol).

The following are some examples of embodiments of the invention.

Example 1

Up to 100; A ml flask equipped with a Teflon magnetic stirrer was charged with 20 ml of toluene, 0.25 ml of 1-hexene, 0.10 ml of 30% toluene solution of sesqui (2-methoxyethoxylalanine) and 2.5 ml of toluene solution of bis (cyclopentadienyl) dichlorotitanium complex. 5,2.10 concentration of ³ mol / first reaction mixture thus obtained was stirred at 298 K and hydrogen was bubbled above for Θ hours maintained hydrogen pressure of 101.3 kPa. after completion of the reaction, the reaction mixture was analyzed by gas chromatography. Yield hexane was 97% Example 1

A 250 ml flask equipped with a Teflon magnetic stirrer was charged with 3Ό ml of toluene and 0.108 g of a 6% sodium dihydrobis (2-methoxyethoxo) aluminate toluene solution and a suspension prepared from 0.044 g of aluminum chloride, 6 ml of toluene and 0 ml was added over 10 minutes. The dropper was washed twice with 2 ml of toluene, and after 10 minutes 0.5 ml of 3-hexane and 5 ml of a toluene solution of bis (cyclopentadienyl) dichlorotitanium complex at a concentration of 5.2.10 ^{1 3} mol / ml were added. 1. The resulting reaction mixture was stirred at 298 K and hydrogen pressure was maintained at 101.3 kPa for 6 hours by bubbling hydrogen over.

Claims (2)

20 ml of toluene, 0.1 ml of a 30% toluene solution of sesqui (2-methoxy) ethoxyalan, 2.5 ml of a toluene solution of bis (cyclopentadienyl) dichlorotitanium complex at a concentration of 5.2 W were added to a 100-roll flask equipped with a Teflon magnetic stirrer. ^-3 mol / 1 and 0.2 to 0.3 ml of the olefin. the resultant mixture was stirred at 298 K and admitting hydrogen to the bottom was maintained at a pressure above 1013 mbar of hydrogen. After the reaction, the reaction mixture was analyzed by Yields are given in the table. olefin recovered hydrocarbon yield ('%) 2-pentene pentane 96 cyclohexene cyclohexane 95 1-Hepten heptane 9Θ 1-okten octane 92 píkdmSt A process for the preparation of a bis (cyclopentadlenyl) dichlorotitanium complex for the low pressure hydrogenation of olefins in an aromatic hydrocarbon medium, characterized in that the bis (cyclopentadienyl) divynalysis of the chlorotitanium complex in the hydrogenated olefin reaction mixture is reduced by sesqui ) dichlorotitanium complex 7 to 9: 1.