Ag/TS-1催化丙烯直接气相氧化合成环氧丙烷

PROPYLENE OXIDATION TO PROPYLENE OXIDE OVER Ag/TS-1 CATALYST IN THE GAS PHASE

丙烯气相催化氧化合成环氧丙烷的反应,以Ag/TS-1作催化剂,分子氧作氧化剂,在实验室常压固定床石英反应器上进行。考察了Ag/TS-1催化剂的制备条件、处理方式及反应条件对丙烯直接气相氧化反应性能的影响,即Ag负载量、载体、TS-1载体的n(Si)/n(Ti)、催化剂焙烧温度、催化剂焙烧方式、反应温度(θ)、气体体积空速(GHSV)、V(C3H6)/V(O2)及V(C3H6)/V(H2)等因素对反应性能的影响。结果表明,H2是反应过程中不可缺少的物种。Ag的最佳负载量为2％(质量分数),载体TS-1的最佳n(Si)/n(Ti)=64,Ag/TS-1催化剂在450℃空气中焙烧效果最好。w(Ag)=2％的Ag/TS-1(n(Si)/n(Ti)=64),在150℃、V(C3H6):V(O2):V(H2):V(N2)=1:2:3:12、GHSV=4000 h-1条件下反应,催化剂的性能最佳;在该条件下反应70 min后,丙烯转化率(x(C3H6))和环氧丙烷选择性(SPO)分别为1.37％和93.51％。

Synthesis of propylene oxide through gas phase epoxidation of propylene using molecule oxygen as an oxidant over lab-prepared Ag/TS-1 catalyst and the lab fixed-bed reaction unit with quartz reactor was studied. The preparation conditions of Ag/TS-1 catalyst such as, Ag loading, type of support, the Si/Ti mol ratio of TS-1, calcination conditions, were investigated. The effects of reaction conditions including reaction temperature, gas velocity, volume ratio of C3H6/O2 and C3H6/H2 on catalyst performance were also investigated. The optimum Ag loading w(Ag) was of 2% (mass percent) and n(Si)/n(Ti) was of 64 (support), and the optimum calcination temperature was 450°C in air for Ag/TS-1 catalyst. The reaction when carried out at 150°C by passing the reactant mixture of C3H6, O2, H2 and N2 through the reactor at a volume ratio of 1:2:3:12 with a space velocity of 4000 h-1 is optimum. After 70 min reaction, propylene conversion (x(C3H6)) and selectivity to propylene oxide (SPD) were 1.37% and 93.51%, respectively.