椰壳纤维炭磺酸的制备及其催化性能研究

Preparation and catalytic properties of coconut husk fibers char sulfonic acid

以海南椰壳纤维为原料,采用减压热解炭化的方法制备椰壳纤维炭材料,以发烟硫酸作为磺化剂制备椰壳纤维炭磺酸。采用FTIR、DSC-TGA和SEM等分析手段对椰壳纤维炭磺酸进行结构及形貌表征,并将其用于催化合成乙酸乙酯反应研究。实验结果表明,成功制得椰壳纤维炭磺酸,其适宜的制备条件为:炭化温度300℃、炭化时间2 h、20%发烟硫酸作磺化剂、磺化时间3 h、磺化温度90℃、炭材料的质量与磺化剂的体积之比1∶32 g/mL。通过FTIR分析表明炭材料磺化后出现磺酸基团特征峰,通过DSC-TGA分析表明该酸中心在180℃以下稳定,通过SEM观察发现椰壳纤维炭磺酸材料表面具有大量密集网状孔洞,比表面积大,有利于催化反应进行。催化实验结果表明,在以椰壳纤维炭磺酸为催化剂合成乙酸乙酯反应中产率可达91.74%,椰壳纤维炭磺酸循环使用4次催化活性依然较高。

Hainan coconut husk fibers were taken as raw material to prepare and produce carbon materials by decompressive pyrolysis carbonization,meanwhile the coconut husk fiber char sulfonic acid was prepared by fuming sulfuric acid as sulfonating agent.By using analysis methods of FTIR,DSC-TGA,and SEM and so on,the coconut husk fiber char sulfonic acid was constructed and profiled,which was used for catalytic synthesis of the performance and properties of ethyl acetate.The results showed that the suitable conditions of producing coconut husk fiber char sulfonic acid were the carbonization temperature of 300℃,the carbonization duration of 2 h,the sulfonating agent of 20%fuming sulfuric acid,the sulfonating duration of 3h,the sulfonating temperature of 90℃and the ratio of the quality of carbon and the volume of sulfur of 1∶32 g/mL.FTIR analysis illustrated that the characteristic peak of sulfonic acid groups appeared after sulfating the carbon materials.The center of acid was stable below 180℃according to DSC-TGA analysis.A large number of dense mesh holes on the surface of coconut husk fiber char sulfonic acid material were found by observing through SEM,which was larger than superficial area and also better for catalytic reaction.The results of catalytic experiments demonstrated that the yield of ethyl acetate could reach 91.74%in the synthesis of ethyl acetate with coconut husk fibers char sulfonic acid as catalyst.Additionally,the activity of the catalyst was still high even though the coconut husk fibers char sulfonic acid catalyst had been used for 4 times circularly.