1,4-丁炔二醇选择性加氢催化剂:Pd/ZrO_(2)及其碱金属改性

Selective hydrogenation of 1,4-butynediol to 1,4-butenediol:Pd/ZrO_(2)catalyst and alkali metals modification

以Zr(OH)_(4)焙烧得到的ZrO_(2)为载体,采用等体积浸渍法制备了负载型Pd/ZrO_(2)和碱金属(M)改性的催化剂(Pd/M/ZrO_(2)),通过XRD、BET、TEM及HRTEM、CO_(2)-TPD、XPS对催化剂进行了表征,并评价了其在1,4-丁炔二醇(BYD)选择性加氢制1,4-丁烯二醇(BED)反应中的活性、选择性和稳定性,探究了反应气氛及碱金属改性对其活性和稳定性的影响。结果表明,1.0%Pd/ZrO_(2)(1.0%为Pd的质量分数)在50℃,2.40 MPa H_(2)下,能够催化BYD选择性加氢生成BED,有较高的催化活性[0.048 molBYD/(g Pd·s)],在BYD完全转化的条件下,BED的选择性为91.2%。氨的引入能够显著抑制催化剂加氢活性,提高BED的选择性。在BYD接近完全转化时,BED的选择性可达95.6%。向ZrO_(2)载体中引入少量碱金属(Li、Na、K、Rb、Cs),能够提高BED的选择性,其中,Rb的影响最为显著,BED的选择性可达94.1%。

Pd/ZrO_(2) and alkali metals(M)modified Pd/M/ZrO_(2) catalysts were prepared by incipient-wetness impregnation with ZrO_(2) obtained from Zr(OH)_(4) calcination as support,and characterized by XRD,BET,TEM and HRTEM,CO_(2)-TPD,XPS.The activity,selectivity and stability of the catalysts in the selective hydrogenation of 1,4-butynediol(BYD)to 1,4-butenediol(BED)were evaluated,and the influence of reaction atmosphere and alkali metals modification on the activity and stability of the catalysts were analyzed.The results showed that under 50℃and 2.40 MPa H_(2)pressure,1.0%Pd/ZrO_(2)(1.0%being the mass fraction of Pd)exhibited high catalytic activity of 0.048 molBYD/(gPd·s),and BED selectivity of 91.2%with complete conversion of BYD.The introduction of ammonia into the reaction mixture inhibited the hydrogenation activity and improved the BED selectivity to 95.6%with complete conversion of BYD.Modification of Pd/ZrO_(2) with alkali metals(Li,Na,K,Rb,Cs)improved the selectivity of BED with Rb the most effective modifier showing BED selectivity up to 94.1%.