Selective Epoxidation of Styrene to Styrene Oxide over TS-1 Using Urea–Hydrogen Peroxide as Oxidizing Agent
Selective Epoxidation of Styrene to Styrene Oxide over TS-1 Using Urea–Hydrogen Peroxide as Oxidizing Agent
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DOI：
10.1006/jcat.2001.3352
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发表时间：
2001-11
影响因子：
7.3
通讯作者：
S. Laha;R. Kumar
中科院分区：
文献类型：
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作者：
S. Laha;R. Kumar
摘要以无水尿素-过氧化氢加成物为氧化剂，在钛硅分子筛（TS-1）催化下苯乙烯环氧化反应中，氧化苯乙烯的选择性高达85%左右。当过氧化氢水溶液用于苯乙烯环氧化反应时，氧化苯乙烯的选择性很差（5-10%），主要是由于其异构化为苯乙醛。通过与无水尿素-过氧化氢和TS-1的固-固相互作用，也观察到不同类型的钛-超氧配合物的形成。这是证实了在UV-Vis区域（300-500 nm）的特征连续吸收带，也通过强烈的和各向异性的EPR光谱的超氧自由基离子稳定的Ti（IV）中心的TS-1样品。
Abstract The use of anhydrous urea–hydrogen peroxide adduct as an oxidizing agent in the epoxidation of styrene catalyzed by a titanium–silicate (TS-1) molecular sieve resulted in very high selectivity (∼85%) for styrene oxide. When aqueous hydrogen peroxide (H 2 O 2 ) was used for styrene epoxidation, the styrene oxide selectivity was very poor (5–10%) mainly due to its isomerization into phenylacetaldehyde. The formation of different types of Ti–superoxo complexes was also observed by the solid–solid interaction with anhydrous urea–hydrogen peroxide and TS-1. It was confirmed by the characteristic continuous absorption band in the UV-Vis region (300–500 nm) and also by an intense and anisotropic EPR spectrum for the superoxide radical ion stabilized on Ti (IV) centers of TS-1 samples.