乙烯直接氧化制乙酸的研究 Ⅱ.助剂对Pd-Se/H_4SiW_(12)O_(40)/SiO_2催化性能的影响

Investigation on Direct Oxidation of Ethylene to Acetic Acid Ⅱ. Effect of Promoters on Catalytic Performance of Pd-Se/H_4SiW_(12)O_(40)/SiO_2

研究了不同助剂促进的负载型Pd Se/H4SiW1 2 O40 /SiO2 催化剂对乙烯直接氧化制乙酸反应的影响 .采用固定床微反装置评价了催化剂的性能 ,并采用C2 H4和O2 吸附量测定、吸附C2 H4的TPD MS和TPSR MS等技术对催化剂进行了表征 .结果表明 ,以SiO2 为载体 ,以硅钨酸为助剂 ,Pd Se Na Ru组成的催化剂体系其催化性能比文献报道的结果明显提高 .在原料气配比n(C2 H4 ) ∶n(N2 ) ∶n(O2 ) ∶n(H2 O) =5 5∶1 4∶9∶2 2 ,反应物空速GHSV =384 4h-1 ,反应压力 p =1 4MPa ,反应温度θ =1 5 5℃条件下 ,乙烯的转化率和乙酸的选择性分别为 8 0 %和 87 4 % ,乙酸的单程时空产率达 372 0g/ (L·h) .吸附量测定表明 ,吸附在催化剂表面上的C2 H4/O2

The effect of different promoters on ethylene oxidation to acetic acid over Pd Se/H 4SiW 12 O 40 /SiO 2 catalyst was investigated. It was found that Pd Se Na Ru/H 4SiW 12 O 40 /SiO 2 catalyst exhibited excellent catalytic performance for direct oxidation of ethylene to acetic acid. The conversion of C 2H 4 and the selectivity for acetic acid were 8 0% and 87 4% respectively, and the space time yield of acetic acid was up to 372 0 g/(L·h) under the reaction conditions of n (C 2H 4) ∶ n (N 2) ∶ n (O 2) ∶ n (H 2O) =55∶14∶9∶22, GHSV= 3?844 h -1 , p =1 4 MPa and θ =155 ℃. The catalyst was characterized by TPD MS, TPSR MS and adsorption measurement of C 2H 4 and O 2. The results showed that high C 2H 4/O 2 ratio adsorbed on the catalyst surface was favorable for the increase of selectivity for acetic acid.