Large-batch high-pressure synthesis method of polycarbosilane(PCS)

Abstract

The invention provides a large-batch high-pressure synthesis method of PCS. The method comprises the following steps: (1) placing a silicon-containing raw material and a catalyst in a stainless steelautoclave, replacing the gas in the autoclave with high-purity nitrogen, and sealing; (2) carrying out temperature programming on the temperature in the autoclave to reaction temperature, and after the reaction time, cooling to obtain a crude PCS product; (3) dissolving the crude PCS product with xylene, filtering and carrying out reduced pressure distillation on filtrate and then cooling to obtain PCS; the catalyst is an organometallic compound containing one or more of boron, aluminum, titanium, zirconium and hafnium, including but not limited to boron alkyl, alkoxy boron, aluminum alkyl, alkoxy aluminum, alkyl titanium, alkoxy titanium, titanium metallocene, alkyl zirconium, alkyl zirconium oxide, zirconium metallocene, alkyl hafnium, alkoxy hafnium, and hafnium compound; the reaction temperature is 400 to 450 DEG C; the pressure is 4 to 10MPa, the reaction time is 2 to 12 hours; and the volume of the autoclave is 50 to 10000L.

Description

technical field [0001] The invention generally belongs to the technical field of polycarbosilane synthesis, and in particular relates to a large-volume high-pressure synthesis method of polycarbosilane. Background technique [0002] Polycarbosilane (Polycarbosilane, PCS) is an important raw material for preparing SiC fibers by precursor pyrolysis conversion method, and preparing SiC-based composite materials such as C / SiC and SiC / SiC by precursor impregnation and pyrolysis (PIP). It has important applications in the fields of aerospace, high-performance weapons and equipment, energy and chemical industry. [0003] There are many ways to synthesize polycarbosilane, mainly including the following four methods. [0004] (1) Direct synthesis method: For example, carbosilanes and polycarbosilanes with relatively regular structures can be obtained by using organosilicon monomers and reacting with Grignard reagents. People such as J P Wesson react chlorine-containing organosilico...

AI Technical Summary

Problems solved by technology

[0009] The purpose of the present invention is to overcome the defects of high-pressure synthetic PSC high temperature and high pressure in the above-mentioned prior art that lead to high equipment cost, and provide a large-scale high-pressure synthesis method of polycarbosilane. By adding a catalyst, the reaction temperature is controlled not to exceed 450°C, so that the pressure in the reactor is controlled at no more than 10MPa, and a stainless steel autoclave can be used. The volume of the autoclave can range from 50 liters to 10,000 liters, and the synthesis yield of polycarbosilane can reach more than 50%, which is remarkable. Shorten the preparation cycle and reduce the cost of mass production