PtCl_6^(2-)插层Mg/Al水滑石的合成及催化烯烃硅氢加成反应

Preparation of PtCl_6^(2-) Intercalated Mg/Al-hydrotalcite Catalyst and Its Catalytic Activities for the Hydrosilylation of Olefins

以尿素作为沉淀剂制备了镁铝水滑石前驱体,与氯铂酸溶液进行阴离子交换反应得到氯铂酸根插层镁铝水滑石催化剂。通过X射线粉末衍射(XRD)、氮气吸附脱附等温线和热重分析(TG-DTA)等对水滑石前驱体和插层催化剂进行了表征,实验研究了反应温度、反应时间和催化剂使用量对辛烯与三乙氧基硅烷硅氢加成反应产物收率的影响,及催化剂的可重复利用性能。研究表明,辛烯与三乙氧基硅烷的摩尔比为1∶1,反应温度为100°C,反应时间为5 h,催化剂中Pt含量为8.70×10-4mmol时,辛基三乙氧基硅烷收率达到91.2%,且在连续使用5次后,催化剂的反应活性没有明显的下降。此外,实验结果还表明所制备催化剂可以有效催化不饱和烯烃和三乙氧基硅烷的硅氢加成反应,且催化剂可以通过简单的离心进行有效分离。

In this paper, a Mg/Al-hydrotalcite precursor was prepared by co-precipitation using urea as a precipitant, PtCl62- ions intercalated Mg/Al-hydrotalcite catalyst was obtained by anion exchange reaction of precursor with chloroplatinic acid solution. The powder X-ray diffraction （XRD）, N2 nitrogen adsorption-desorption isotherms and thermal gravimetric analyses （TG-DTA） were applied to characterize the catalyst precursor and the PtCl62-intercalated Mg/Al-hydrotalcite catalyst. The effect of reaction temperature, reaction time and the content of catalyst on the target product yield of 1-octene with triethoxysilane were investigated, the reusable properties of this novel catalyst was aslo evaluated. Experimental results showed that under the following reaction conditions：the mole ratio of 1-octene and triethoxysilane is 1：1, reaction temperature is 100 °C, reaction time is 5.0 h, the Pt content of catalyst is 8.70 × 10-4 mmol, the yield of n-octyltriethoxysilane can reach 91.2 %, and the catalyst can be reused several times without noticeable loss of activity. Furthermore, it was found that the supported catalyst is an efficient catalyst for hydrosilylation of olefins with triethoxysilane and the catalyst can be recovered by simple centrifugal separation.