胶囊化Ni(acac)_2·2H_2O对环己烯环氧化催化性能的研究

Catalytic Epoxidation of Cyclohexene over Encapsulated Ni(acac)_ 2 ·2H_2 O Catalysts

利用溶胶 凝胶技术包容Ni(acac) 2 ·2H2 O络合物催化环己烯的环氧化。应用FT IR、N2 吸附测定比表面积等方法对凝胶催化剂进行表征。考察包容条件对催化活性的影响。在pH =3 ,n(H2 O) /n(Si) =6,干燥温度为 80℃时 ,凝胶催化剂的催化效果最佳 ;且与均相催化剂的催化活性相当。循环使用 3次仍保持较高的催化活性 ,解决了均相催化剂对设备腐蚀和无法重复利用的问题。对包容的Fe(acac) 3 和Co(acac) 2 ·2H2 O进行对比 ,结果表明包容的乙酰丙酮镍催化剂催化活性最佳。

Ni(acac) 2 ·2H 2 O was encapsulated in SiO 2 by a Sol gel method and used in epoxidation of cyclohexene. The catalysts were characterized by FT IR spectroscopy and BET. The best encapsulation conditions were pH=3, n (H 2O)/ n (Si)=6, drying temperature 80 ℃. The activity of the encapsulated Ni(acac) 2 catalyst decreased not much after 3 experiments. The prepared encapsulated catalyst has the advantages of avoiding corrosion of apparatus, regeneration and high yield of epoxide of cyclohexene(ECH) as compared with encapsulated Fe(acac) 3 and Co(acac) 2 ·2H 2 O .