Al_2O_3催化剂催化呋喃与H_2S反应制备噻吩

研究了呋喃与H2S在不同温度下焙烧的Al2O3催化剂上反应制备噻吩。实验结果表明,Al2O3催化剂的焙烧温度为550℃时,在液态空速0.2h-1、n(H2S)∶n(呋喃)=10、反应温度500℃的条件下,目标产物噻吩的收率达到90.2%。采用X射线衍射和BET方法对不同温度下焙烧的Al2O3催化剂的晶相结构和比表面积进行了表征,表征结果显示,随焙烧温度的升高,Al2O3的晶相结构由γ-相向α-相转变,同时比表面积由226.13m2/g急剧减小到2.22m2/g。采用吡啶吸附傅里叶变换红外光谱对Al2O3催化剂的表面酸性进行了表征,并结合实验数据对反应机理进行了探讨,得出Al2O3催化剂表面上L酸中心是呋喃与HS反应制备噻吩的催化活性位。

Synthesis of Thiophene from Furan and H2S over Al2O3 Catalyst

Synthesis of thiophene from furan and H2S over alumina catalysts calicined at different temperatures was studied. High yield to thiophene(90.2%) was achieved from furan and hydrogen sulfide over alumina calcined at 550 ℃ under conditions of: LHSV 0.2 h-1, n(H2S) ∶n(furan) 10 and temperature 500 ℃. Crystal structure and specific surface area of the catalysts were characterized by means of XRD and BET. Crystal form of the alumina transformed from γ-A12O3 to α-A12O3 with rising of calcinations temperature to about 1 300 ℃ and dramatically decreasing of specific surface area from 226.13 m2/g to 2.22 m2/g. Acid sites on alumina surface were determined by FTIR with pyridine adsorbed on alumina calicined at different temperatures. Reaction mechanism of furan and H2S over alumina was discussed. Lewis acid sites are active sites for thiophene synthesis from furan and hydrogen sulfide over Al2O3.