碳基磺酸化固体酸材料的制备及其催化性能

Preparation and Catalytic Performance of Sulfonated Carbon-Based Solid Acid

以蔗糖为原料,浓硫酸为磺酸化试剂制备了碳基磺酸化固体酸材料,考察了其催化对苯二酚烷基化和乙酸乙酯水解反应的性能.结果表明,该催化剂对这两个反应都具有较高的催化活性,在150oC反应4h后,对苯二酚转化率和2-叔丁基对苯二酚收率分别达到了91%和60%,在60oC反应12h,乙酸乙酯达到了平衡转化率94%.但催化剂稳定性较差,尤其在对苯二酚烷基化反应中失活严重,重复使用一次后,催化剂活性下降超过30%.详细考察了反应温度和溶剂对催化剂稳定性的影响,结果表明,该固体酸在低温的水相或非极性溶剂中较为稳定.通过酸碱滴定、红外光谱和紫外可见光谱等表征手段,对催化剂的失活原因进行了探讨,初步认定催化剂的失活是由于表面磺酸基团在反应过程中脱落所致.催化剂活性可以通过再磺酸化得到恢复.

Sulfonated carbon-based solid acids were prepared by sulfonation of incompletely carbonized sucrose, and their catalytic properties in the alkylation of hydroquinone and the hydrolysis of ethyl acetate were investigated. These solid acids exhibited high activity for both reactions, in which the conversion of hydroquinone and yield of 2-tert-butylhydroquinone reached 91% and 60%, respectively, at 150 ℃ for 4 h, while the conversion of ethyl acetate reached 94% at 60℃ for 12 h. However, the stability of the solid acids was poor, especially in the alkylation of hydroquinone, where the conversion dropped from 91% to 62% after the first run. The characterization results of acidity measurement and IR and UV-Vis spectroscopy indicate that the deactivation is probably due to the leaching of sulfonic group from the surface of the catalyst. The effect of the reaction temperature and the type of solvent were also investigated, showing that these solid acids are more stable in the aqueous solution or non-polar solvent at low temperature. The deactivated catalysts can be regenerated by resulfonation and their catalytic activity can be fully restored.