摘要
通过尿素沉淀法制备了以锌基为主要活性组分的不同的复合型氧化物催化剂,考察了尿素与1,2-丙二醇(PG)合成碳酸丙烯酯(PC)反应的催化性能。用XRD,SEM,BET,CO2-TPD对催化剂进行了表征。结果表明,催化剂的强碱性位数量可能是影响催化活性的关键因素,在此基础上推出碱催化机理:较强的碱强度有利于降低中间产物羟丙基氨基甲酸酯(HPC)转化为PC的活化能。在反应温度170℃,反应时间1 h,PG/尿素摩尔比1.5,0.6 g催化剂(占尿素质量的2%),反应压力3.99×104Pa的条件下,PC收率高达99.8%。n(锌)∶n(镁)=1∶4,催化剂经过5次再生,PC收率降低了2.2%。
A series of zinc-based mixed oxide catalysts were prepared by urea precipitation. The catalysts were characterized by means of XRD,SEM,BET and CO2-TPD and then studied for the synthesis of propylene carbonate（ PC） from urea and 1,2-propylene glycol. The results show that the amount of alkali may be the main factor that affects the catalytic activity,based on which the base catalysis mechanism is proposed： the strong basic sites may be conducive to the reduction of the activation energy of the reaction between PC and HPC. The yield of propylene carbonate could reach as high as 99. 8% under the optimum reaction conditions： 170 ℃,1 h,n（ PG） / n（ Urea） = 1. 5,3. 99 ×104Pa,0. 6 g catalyst（ 2% of the mass of urea）. After five times＇ regeneration of the catalyst 〔n（ Zn）∶ n（ Mg） = 1∶4〕,PC yield was reduced by 2. 2%.
出处
《精细化工》
EI
CAS
CSCD
北大核心
2015年第3期281-288,共8页
Fine Chemicals
基金
中国科学院院地合作项目~~
关键词
锌基
尿素
碳酸丙烯酯
羟丙基氨基甲酸酯
催化技术
zinc base
urea
propylene carbonate
hydroxypropyl carbonate
catalysis technology
