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用HCl酸化-乙醚萃取分别制备了La~(3+)掺杂量不同的硅钨杂多酸,并将其负载在碳纳米管上,同时用XRD,FT-IR,SEM,TG,程序升温技术和微反色谱装置等对制备的催化剂结构、形貌、酸种类、热稳定性、吸附性能和活性等进行了表征和评价。结果表明:掺杂La~(3+)后的负载型硅钨杂多酸保持Keggin结构,表面同时具有B酸和L酸中心,La~(3+)掺杂量主要影响L酸中心的数量,其中SiWLa-0.2具有较强和较多的L酸中心,SiWLa-0.15具有较强的B酸中心;较强的B酸中心有利于α-蒎烯发生解离附态。La~(3+)掺杂量影响α-蒎烯异构化反应的产物分布,其中SiWLa-0.20催化剂中α-松油烯含量为61.65%,表明L酸中心有利于单环萜烯的生成。
Hydrogenated heterosilicophosphates with different La 3+ loadings were prepared by HCl acidification-ether extraction and supported on carbon nanotubes. The results of XRD, FT-IR, SEM, TG and temperature program The structure, morphology, acidity, thermal stability, adsorption properties and activity of the prepared catalyst were characterized and evaluated by means of UV-Vis absorption spectroscopy, The results showed that Keggin structure was supported by La 3+ -doped heteropolytungstate, with both B and L acid sites on the surface. The amount of La 3+ doping mainly affected the number of L acid centers , Of which SiWLa-0.2 has stronger and more L acid sites, SiWLa-0.15 has stronger B acid sites, and stronger B acid sites favor the dissociation of α-pinene. The La 3+ doping amount affected the product distribution of α-pinene isomerization reaction, in which the content of α-terpinene in SiWLa-0.20 catalyst was 61.65%, indicating that the L acid center is conducive to the formation of monocyclic terpenes .