SO_4^(2-)/TiO_2-HZSM-5型固体酸催化合成尿囊素

Preparation of Solid Acid SO_4^(2-)/TiO_2-HZSM-5 and its Application in the Synthesis of Allantoin

以固相分散法制备了用于尿囊素合成的SO42-/TiO2-HZSM-5固体酸催化剂。考察了制备条件(HZSM-5的硅铝摩尔比、二氧化钛与HZSM-5的质量比、浸渍时间、浸渍酸浓度、焙烧温度)对催化剂结构和性能的影响。采用X-射线衍射(XRD)、氮气低温物理吸附(BET)、傅立叶红外(FT-IR)、吡啶吸附红外(Py-IR)、以及扫描电子显微镜(SEM)等技术,对所制备的催化剂的晶相结构、表面酸性位及比表面积等性能进行了表征。结果表明,催化剂的优化制备条件为:HZSM-5的硅铝比为25,m(二氧化钛)∶m(HZSM-5)=2∶1,硫酸浸渍浓度为0.5 mol/L,催化剂焙烧温度为500℃。在优化条件下,尿囊素收率为58.4%。

By means of solid-phase dispersion method,a solid acid catalyst SO42-/TiO2-HZSM-5 for the synthesis of allantion was developed and the various factors affecting the structure and properties of the solid acid were studied.Optimized conditions were obtained as follows：the mass ratio of TiO2 to HZSM-5（Si/Al=25） 2 to 1,thecon centration of H2SO4 0.5 mol/L and the calcination temperature 500℃.The crystal structure,acid center and specific surface area of the catalyst were characterized by XRD,FT-IR,Py-IR,BET and SEM.Under the optimal conditions,allantoin was obtained in 58.4% yield.