~(31)P、~(29)Si MAS NMR 法研究磷酸盐催化剂的结构

用３１Ｐ、２９ＳｉＭＡＳＮＭＲ法研究磷酸盐催化剂在制备过程中形成的结构及吸潮对催化剂结构的影响。结果表明，原料混合后立即生成添加元素的磷酸盐；干燥后，ＳｉＯ２与磷酸以无定型状态相结合；焙烧后大部分转化为焦磷酸硅和正磷酸硅，并且ＳｉＯ２也转化，不同于原料中的ＳｉＯ２；活化后大部分焦磷酸硅转化为正磷酸硅与游离磷酸，一部分正磷酸硅进一步转化为ＳｉＯ２与游离磷酸，转化生成的ＳｉＯ２不同于原料中的ＳｉＯ２，与焙烧后产生的ＳｉＯ２相同；在整个过程中添加元素的磷酸盐结构较为稳定。吸潮试验表明吸潮对催化剂结构无明显影响。将催化剂结构与活性关联，认为在一定范围内充分活化，有利于形成高活性催化剂，并推断吸潮后催化剂经干燥可复原。

Study on the Strcture of Phosphate Catalysts for Oligomerization of Propene by 31 P, 29 Si MAS NMR

Si and 31 P magic angle spinning nuclear magnetic resonance measurements have been performed on solid phosphate catalysts The spectra show that SiO 2 and H 3PO 4 form amorphous state compounds at preparation stage Ⅱ,which transform to Si 3(PO 4) 4 and SiP 2O 7 after calcination,with the structure of SiO 2 changed SiP 2O 7 partly changes to Si 3(PO 4) 4 and H 3PO 4,and Si 3(PO 4) 4 in turn changes to SiO 2 and H 3PO 4 after steam activation;the SiO 2 differs from that present in the raw material Tests indicated that adsorbing water has no important effect on catalyst structure Correlating structure to catalyst activity,we have found that sufficient steam activation favours the formation of high activity catalyst to a certain extent