改性介孔硅负载铂催化合成农用增效剂

Modified mesoporous silica supporting platinum catalyst for synthesis of agricultural synergist

通过壳聚糖(CS)改性介孔二氧化硅,并负载铂得到Pt/CS-SiO_2催化剂,采用红外光谱(FTIR)、氮气吸附脱附(BET)、热重分析(TG)等对催化剂进行表征,同时考察了Pt/CS-SiO_2催化聚醚和三硅氧烷反应合成农用增效剂。结果表明:Pt成功负载在改性介孔硅上,Pt含量为0.85%;催化剂具有良好的重复使用性,使用7次后仍有较高活性,转化率和选择性均在90%以上;合成农用增效剂的最优工艺为n(MDHM):n(HDE)=1:1.1,反应温度为105℃,反应时间为3 h。测试产物在不同pH的水溶液中的水解性能,发现其在中性条件下可以比较稳定地存在。

Pt/CS-SiO_2 catalyst was prepared by impregnating platinum on chitosan modified mesoporous silica and characterized by Fourier Transform Infrared Spectroscopy（FTIR）, nitrogen adsorption-desorption（BET）, thermogravimetric analysis（TGA）. Catalytic performance was evaluated in hydrosilylation of polyether and trisiloxane for synthesizing agricultural synergist. The experimental results showed that Pt was successfully incorporated on modified mesoporous silica at content of 0.85%. The new catalyst had excellent reusability, which still maintained high activity with greater than 90% of both conversion and selectivity after reused seven times. The optimal synthesis condition for agricultural synergist was a mixture of polyether and trisiloxane at a molar ratio of 1：1.1 and 105℃ for 3 h. The agricultural synergist exhibited excellent stability in neutral aqueous solution by hydrolysis assessment at various p H conditions.