二氧化硅负载铂催化剂的制备及其在硅氢加成反应中的应用

Preparation of Silica-supported Platinum Catalyst and its Application in Hydrosilylation

采用乙烯基三乙氧基硅烷对二氧化硅表面羟基进行修饰,再与铂(Pt)配位制得二氧化硅负载卡斯特铂催化剂。以3-氯丙烯与三氯氢硅通过加成反应制备γ-氯丙基三氯硅烷为反应模型,考察了二氧化硅负载铂催化剂的催化性能,研究了催化剂用量、原料配比、反应温度和反应时间对该反应中原料转化率及目标产物选择性的影响,并对回收后的负载铂催化剂进行了活性评价。结果表明,随着负载铂催化剂用量的增加,氯丙烯转化率稍有提高,但γ-氯丙基三氯硅烷选择性降低;与采用等量之比的原料时相比,三氯氢硅用量略微增加时,氯丙烯的转化率由82%提高到90%,γ-氯丙基三氯硅烷选择性没有大幅度变动;随着反应温度的升高,氯丙烯转化率逐渐提高,γ-氯丙基三氯硅烷选择性先略微提高,而后大幅下降。随着反应时间的延长,氯丙烯的转化率先大幅提升,随后缓慢上升并趋于稳定,γ-氯丙基三氯硅烷选择性先提高后保持稳定。该催化剂在三氯氢硅与氯丙烯的硅氢加成反应体系中具有良好的催化活性及选择性,在氯丙烯与三氯氢硅的量之比为1. 1∶1,负载铂催化剂用量为15×10^-6,反应温度为80℃,反应时间为4 h的条件下,氯丙烯转化率为86. 43%,γ-氯丙基三氯硅烷选择性为75. 88%。此外,经第5次回收后使用,催化活性和选择性无明显下降,在工业领域具有潜在应用价值。

The silica-supported Karstedt catalyst was prepared by the reaction of chloroplatinic acid with vinyl silane immobilized on the surface of the fume silica.γ-chloropropyltrichlorosilane was prepared by the reaction of 3-chloropropene and trichlorosilane.The catalytic performance of silica-supported platinum catalyst was studied.The effects of catalyst content,ratio of the raw materials,temperature and time on the conversion of raw materials and the selectivity of target products were investigated.The activity of the recycled supported platinum catalyst was evaluated.Results showed that with the increase of the silica-supported platinum catalyst,the conversion of allyl chloride increased slightly,but the selectivity ofγ-chloropropyltrichlorosilane decreased.Compared with using the same ratio of the raw materials when the amount of trichlorosilane was increased slightly,the conversion of allyl chloride increased from 82%to 90%,and the selectivity of γ-chloropropyltrichlorosilane did not change greatly;as the reaction temperature increased,the conversion of allyl chloride gradually increased.The selectivity ofγ-chloropropyltrichlorosilane increased slightly at first and then decreased significantly.As the reaction time prolonged,the conversion of allyl chloride increased first,then slowly increased and tended to be stable.The selectivity ofγ-chloropropyltrichlorosilane increased first and then kept stable.The catalyst has good catalytic activity and selectivity in the hydrosilylation of trichlorosilane and chloropropene.The ratio of the amount of chloropropene to trichlorosilane is 1.1∶1,and the amount of platinum catalyst is 15×10^-6,under the temperature of 80℃,reaction time of 4h,the conversion of chloropropene was 86.43%,and the selectivity ofγ-chloropropyltrichlorosilane is 75.88%.In addition,after the fifth recycling,there is no significant decrease in catalytic activity and selectivity,and it has potential application in the industry.