作者:M. Sasidharan、Peng Wu、Takashi Tatsumi
DOI:10.1006/jcat.2002.3595
日期:2002.7
epoxidation and successive pinacol formation of tri- and tetraalkyl-substituted olefins using Ti-β/H2O2/H2O as the catalytic system has been investigated. Aluminum-free Ti-β exhibits better activity and pinacol selectivity than TS-1, TS-2, Ti–MCM-22, and mesoporous Ti–MCM-41. Pinacol (vic-diol) is obtained as the major product with small amounts of the side products pinacolone, alcohol (via hydration)
研究了以Ti-β/ H 2 O 2 / H 2 O为催化体系的三烷基和四烷基取代的烯烃的环氧化和频哪醇的连续形成。与TS-1,TS-2,Ti-MCM-22和中孔Ti-MCM-41相比,不含铝的Ti-β具有更好的活性和频哪醇选择性。品纳醇(vic -diol)是主要产物,少量副产物为频哪酮,醇(通过水合)和低聚物。转化率和频哪醇选择性随着反应温度和时间的增加而增加。产物分布随在Ti-β上反应时间的变化而变化,表明环氧化物是初始产物,该产物会发生二级反应,从而生成频哪醇作为主要产物。转化率和H 2O 2的选择性随着CC键上取代基的庞大而降低,但频哪醇的选择性并未受到明显影响。环状1-甲基-1-环己烯的反应性明显低于相应的开链类似物2-甲基-2-丁烯的反应性。对称的四甲基取代的2,3-二甲基-2-丁烯导致中孔硅酸钛TS-1,TS-2和Ti-MCM-22上形成少量的二聚体。当使用乙腈作为助溶剂时,