双杂原子Cr-Co-β沸石的合成及其苯乙烯氧化性能

Synthesis and Catalytic Performance for Styrene Oxidation of Heteroatomic Cr-Co-β Zeolites

采用水热法在Si O2-Cr2O3-Co O-(TEA)2O-H2O-NH4F体系中((TEA)2O:氧化四乙基铵)合成了具有良好结晶的双杂原子Cr-Co-β沸石,通过XRD,FTIR,UV-Vis,TG-DTG,SEM等技术对试样的结构进行了表征。以H2O2为氧化剂氧化苯乙烯为探针反应,考察了Cr-Co-β沸石的催化活性,研究了溶剂种类、金属配比、H2O2与苯乙烯的摩尔比、催化剂用量、反应时间和反应温度等对反应的影响。实验结果表明,以丙酮为溶剂,以n(Si)∶n(Cr+Co)=20的Cr-Co-β沸石为催化剂,在催化剂用量60 mg、苯乙烯用量17 mmol、H2O2与苯乙烯的摩尔比3、反应温度70℃、反应时间7 h的条件下,苯乙烯转化率为88.4%,苯甲醛选择性为85.3%,环氧苯乙烷选择性为10.7%,苯甲醛收率为75.4%。

Well-crystallized heteroatomic Cr-Co-β zeolites were hydrothermally synthesized in a SiO2-Cr2O3-COO-（TEA） 2O-H2O-NH4F system （ （ TEA ） 20： tetraethyl ammonium oxide ） and were characterized by means of XRD, FTIR, UV-Vis, TG-DTG and SEM. The oxidation of styrene to styrene oxide on the Cr-Co-β zeolite catalysts was investigated with 30% （w）H2O2 as oxidant. The effects of solvents, n （Si） ： n （ Cr ＋ Co） in the catalysts, molar ratio of H2O2 to styrene, catalyst dosage, reaction time and reaction temperature on the oxidation were explored. The results indicated that under the conditions of acetone as solvent , 60 mg Cr-Co-β zeolite catalyst with n （Si） ： n（Cr＋Co） 20, styrene 17 mmol, mole ratio of H2O2 to styrene 3, reaction temperature 70 ℃ and reaction time 7 h, the conversion of styrene, the yield of benzaldehyde, the selectivity to benzaldehyde and the selectivity to styrene oxide were 88.4%, 75.4%, 85.3% and 10. 7%, respectively.