RU2320667C1 - Method for preparing 3-chloropropylsilane - Google Patents

Abstract

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to methods for synthesis of (-γ)-propylsilanes substituted at position 3. Invention proposes initial charging a platinum-containing catalyst and 10-30 wt.-% of reaction mass from previous step or vat residues after isolation of the end product from previous step into reactor. Then the mixture is heated to temperature 65°C and silane hydride and allyl chloride are dosed maintaining the mole ratio silane hydride and allyl chloride in the reaction mass = (1.0-1.2):1. Invention provides development of method allowing significant decreasing consumption of catalyst, declining formation of by-side products and enhancing the effectiveness of technological process.

EFFECT: improved method of synthesis.

3 cl, 1 tbl, 10 ex

Description

The invention relates to the field of synthesis of silane monomers, in particular to the synthesis of substituted at position 3 (-γ) propylsilanes.

It is known that from hydridosilanes by the interaction, for example, with allyl chloride in the presence of a platinum catalyst, 3-chloropropylsilanes can be obtained by hydrosilylation reaction:

It is also known that in the interaction of allyl chloride with hydridosilane to produce 3-chloropropylsilane, part of the used allyl chloride reacts with hydridosilane with the formation of propylsilane and chlorosilane:

Based on these features of the reaction between hydridosilane and allyl chloride, the yield of the target product is usually low.

For example, there is a known method of producing organosilanes by the interaction of silicon hydrides with unsaturated compounds in the presence of platinum catalysts, for example, platinum chloride, hydrochloric acid (I.Awer. Chem.Soc, 82, No. 14, 3601-3604), yield of 3-chloropropyl trichlorosilane (3 -HPTHS) - 66%.

A known method of producing alkylsilanes by the hydrosilylation of olefins, which consists in the fact that hydridosilane and olefin are boiled for 16 hours in the presence of a platinum catalyst at 120 ° C. The disadvantage of this method is the long time of the process and the low yield of the target product (50-55%) (DE No. 2302231, 1973).

A known method of producing alkylsilanes by the interaction of hydridosilane and an olefin in the presence of a platinum catalyst deposited on a substrate. The method consists in heating hydridosilane and an olefin to a boil, condensing, introducing a catalyst into the condensate, and continuing to boil the reaction mixture for 27 hours at 85 ° C. The disadvantage of this method is the long time of the process and the low yield of the target product (64-66%) (US No. 4224233, 1990).

The closest analogue to the achieved result and technical essence is the method for producing propylsilane functionalized in position 3, carried out by the reaction of addition of allyl compounds with hydridosilanes at temperatures in the range from 0 to 200 ° C, pressure from 800 mbar to 25 bar in the presence of a platinum catalyst, in which the starting hydridosilane is taken in a 3-100-fold molar excess with respect to the allyl compound (RU No. 2275375, class C07F 7/14, 04/27/2006)

The disadvantages of this method are the use of a large amount of expensive platinum catalyst, a large excess of the starting hydride silane, the formation of a sufficiently large amount of by-products (propene and silicon tetrachloride).

The objective of the invention is to develop a method that will minimize catalyst consumption, reduce the formation of by-products and increase the efficiency of the process.

The problem is solved in that in the method for producing 3-chloropropylsilane by the interaction of hydridosilane (TCS) with allyl chloride (XA) in the presence of a platinum catalyst, according to the invention, the catalyst is initially loaded into the reactor and 10-30 wt.% Of the reaction mass from the previous operation or bottoms after isolation of the target product from the previous operation, then the mixture is heated to a temperature of at least 65 ° C and hydridosilane and allyl chloride are dosed, maintaining the molar ratio of hydridosilane: chl reagents in the reaction mass Risto allyl within (1,0-1,2): 1. Moreover, the process is conducted mainly at 65-85 ° C, and the molar ratio XA: catalyst is at least 1:10 ^-7

The bottom residue after isolation of the finished product mainly has the following composition,%: 3-CPTHC (85-95), propyltrichlosilane (PTXC) (1-5), high-boiling condensation products (2-10). After hydrosilylation from the previous operation, the reaction mass mainly has the following composition,%: TCS (0.1-3), XA - (0.1-2), silicon tetrachloride (CCC) (10-16), PTHS (2-5 ), 3-CPTHC (70-80).

The loading of the bottom residue after separation of the finished product or reaction mass from the previous hydrosilylation operation in an amount less than 10% is insufficient to create optimal mixing conditions in the reactor, and in an amount of more than 30% it is not economically feasible.

The optimum process temperature is 65-85 ° C. At a temperature below 65 ° C, the reaction of interaction of HA with TCS (hydrosilylation reaction) does not occur (does not “ignite”), an increase in temperature is required; and raising temperatures above 85 ° C is not economically feasible, because additional energy consumption occurs, and the reaction rate does not increase.

The process in accordance with the invention allows to reduce the consumption of catalyst, because less fresh catalyst is required than for the first operation, in addition, the time of heating the reaction mixture to the required temperature is reduced (the induction period of the reaction is reduced) and the reaction “ignition” time is 4–8 hours, the yield of the target product 3-CPTHC based on CA increases to 80-88%.

The invention is illustrated by the following examples.

Example 1 (comparative). 0.25 moles of allyl chloride (XA), 0.25 moles of trichlorosilane (TCS) and 10 ^-5 moles of the catalyst-Н ₂ PtCl ₆ (PCVC) are placed in a flask equipped with a stirrer, reflux condenser and dropping funnel, and heated to (65- 70) ° C for 6 hours and begin to add a mixture of TCS: HA in a ratio of (1.0-1.25): 1.0 at a rate such that the temperature in the mass is (70-80) under the siphon layer under the reaction mass layer ° C. So, from 2,565 moles of TCS and 2.3 moles of HA, 3-CPTHC is obtained with a yield of 78%, 3.5% of PTCS, 14.5% of CCC are by-produced.

Example 2. 52.7 g of reaction mass from a previous experiment was loaded into a flask, ^10–6 moles of PCVC, the mass was heated to (65-75) ° C for 0.5-1.0 hours, and served by a siphon under a liquid layer a mixture of TCS: XA in the ratio (1.15-1.0): 1.0 at t = (70-80) ° C. Thus, from 2,645 moles of TCS and 2.3 moles of HA, 3-CPTHC is obtained with a yield of 85.8%.

Example 3. 52.7 g of vat 3-CPTHS after the isolation of the desired product (3-CPTHS), 10 ^-6 moles of PCVC are loaded into the flask and heated to (70-80) ° C for 0.5-1.0 hours, then serves a mixture of TCS: HA in a ratio of 1.15: 1 in an amount of 2.599: 2.26 moles. Get 3-CPTHC with a yield of 87%.

Examples 4-5. The process was carried out analogously to example 1, but with a change in the number of loaded components.

Examples 6-8. The process was carried out analogously to example 3, but with a change in the number of loaded components.

Examples 9-10. The process was carried out analogously to example 2, but with a change in the number of loaded components.

The data in examples 4-10 are shown in the table.

Claims (3)

1. The method of producing 3-chloropropylsilane by the interaction of hydridosilane and allyl chloride in the presence of a platinum-containing catalyst, characterized in that the catalyst and 10-30 wt.% Of the reaction mass from the previous operation or bottoms after isolation of the target product from the previous operation are initially loaded into the reactor, then the mixture heated to a temperature of 65 ° C and dosed hydridosilane and allyl chloride, maintaining in the reaction mass the molar ratio of hydridosilane and allyl chloride is 1.0-1.2: 1. 2. The method according to claim 1, characterized in that the process is conducted mainly at 65-85 ° C. 3. The method according to claim 1 or 2, characterized in that the molar ratio of allyl chloride: catalyst in the reaction mass is at least 1:10 ^-7 .