SO_4^(2-)/ZrO_2制备及其对双戊烯催化脱氢的影响

Preparation of SO_4^(2-)/ ZrO_2 and its effect on selective dehydrogenation of dipentene

制备了SO42-/ZrO2固体酸催化剂,考察了制备工艺与反应条件对双戊烯催化脱氢性能的影响,采用X-射线衍射、傅里叶变换红外光谱和热分析等对其进行表征,并用正丁胺电位滴定法测定催化剂的酸量.结果表明,焙烧温度为500-700℃,催化剂中ZrO2开始出现四方晶相和单斜晶相,且SO2-4与ZrO2主要以螯合和桥式配位方式结合.降低H2SO4浸渍液浓度、提高焙烧温度与反应温度均有利于双戊烯转化率的提高以及脱氢产物对伞花烃选择性的增大.适宜的工艺条件为:H2SO4浸渍液浓度0.1 mol·L-1,焙烧温度700℃,反应温度170℃,反应时间1 h,在催化剂用量(质量分数)为2%时,双戊烯转化率和对伞花烃的选择性分别为100%和33.39%.

SO42-/ ZrO2 solid acid catalyst was prepared,and the effects of catalyst synthesis and reaction conditions on its catalytic activity were investigated as well. The catalysts were characterized by X-Ray diffraction( XRD),Fourier transform infrared spectroscopy( FT-IR),thermogravimetry analysis( TG) and differential scanning calorimetry( DSC). The number of acid sites on catalysts was measured by the potentiometric titration of nbutylamine. The results indicated that tetragonal and monoclinic phase of ZrO2( in catalysts) appeared under the calcination temperature of 500-700 ℃,and the SO2-4 could be combined with ZrO2 through chelate and bridge connection. The decrease of H2SO4 concentration and the increase of calcination temperature and reaction temperature both contributed to the increase of dipentene conversion rate and the selectivity of p-cymene. Under optimal conditions such as H2SO4 concentration of 0.1 mol·L-1,catalyst calcination temperature of 700 ℃,reaction temperature of 170 ℃,reaction time of 1h and catalyst dosage of 2%,the dipentene conversion rate and the p-cymene selectivity could reach to 100% and 33.39%,respectively.