超稳Y沸石负载杂多酸催化剂的制备、表征及催化性能 Ⅰ.制备及表征

Preparation,Characterization and Catalytic Behavior of Heteropoly Acid Immobilized on Ultra Stable Y Zeolite I.Preparation and Characterization

采用过量浸渍法制备了一系列超稳Y沸石(USY)负载磷钨酸(PW)催化剂,并用XRD、热分析、N2吸附、NH3-TPD和IR等手段对其物化性质进行了详细的表征。结果表明,负载磷钨酸后,试样仍然保持较大的比表面积和与USY相近的二次中孔体积。负载量达30%时,磷钨酸仍在USY表面高度分散。与纯磷钨酸相比,PW/USY试样的热稳定性显著提高。PW/USY的酸量较磷钨酸和USY均有较大提高,在负载量为10%处酸量最大,负载量进一步增大,酸量下降,酸强度提高。PW/USY试样同时存在B酸和L酸中心,PW与USY之间可能存在弱相互作用。

1,2-Tungstophosphoric acid (PW) immobilized on ultra stable Y (USY ) zeolite (PW/USY) with different PW loadings was prepared by impregnation at room temperature. The catalysts were characterized by N2-adsorption, XRD, TG/DS C, NH3-TPD and FT-IR techniques. It was found that the various PW/USY catalysts re tained the high surface area and micropore structure of USY with abundant second ary pore system. When the PW loading was as high as 30%,PW could highly disper s e on the surface of USY because of the interaction of PW and pore wall s of USY. Moreover,the thermal stability was improved as PW was supported on U SY. O n the other hand,both Brnsted and Lewis acid were observed on PW/USY catalyst s . Comparing to pure PW or USY,PW/USY catalysts possess larger amount of acid s ites.