CAJ | 학술논문

通过共浸渍法合成了一系列担载型杂多酸银盐催化剂AgxH3-xPW/SiO2(x=0.5,1.0,1.5,2.0,2.5,3.0),由于催化剂在极性溶剂中的不溶性,在合成聚四氢呋喃的反应中显示了高反应活性和稳定性能. Ag离子取代含量和银盐的担载量对催化剂活性会产生显著影响. Ag离子含量的不同会导致磷钨酸银盐的晶相结构和催化剂的酸性质发生变化. x=2.0时,催化剂Ag2HPW/SiO2达到最大酸强度和最高催化聚合反应活性.当银盐Ag2HPW的担载量为30%(质量分数)时,催化剂能达到高分散度和高的四氢呋喃聚合反应活性.与普通二氧化硅担载的磷钨酸催化剂HPW/SiO2对比,担载型磷钨酸银盐30%Ag2HPW/SiO2拥有优异的重复使用性能,循环4次后催化活性只有轻微下降.通过引入Ag离子合成的新型担载磷钨酸银盐30%Ag2HPW/SiO2,反应稳定性能明显改进,得到拥有稳定平均分子量的产物聚四氢呋喃.
통과공침지법합성료일계렬담재형잡다산은염최화제AgxH3-xPW/SiO2(x=0.5,1.0,1.5,2.0,2.5,3.0),유우최화제재겁성용제중적불용성,재합성취사경부남적반응중현시료고반응활성화은정성능. Ag리자취대함량화은염적담재량대최화제활성회산생현저영향. Ag리자함량적불동회도치린오산은염적정상결구화최화제적산성질발생변화. x=2.0시,최화제Ag2HPW/SiO2체도최대산강도화최고최화취합반응활성.당은염Ag2HPW적담재량위30%(질량분수)시,최화제능체도고분산도화고적사경부남취합반응활성.여보통이양화규담재적린오산최화제HPW/SiO2대비,담재형린오산은염30%Ag2HPW/SiO2옹유우이적중복사용성능,순배4차후최화활성지유경미하강.통과인입Ag리자합성적신형담재린오산은염30%Ag2HPW/SiO2,반응은정성능명현개진,득도옹유은정평균분자량적산물취사경부남.
@@@@A series of supported silver salts of heteropolyacid AgxH3-xPW/SiO2 (x=0.5, 1.0, 1.5, 2.0, 2.5, 3.0) were synthesized and showed high reactivity and stability in tetrahydrofuran polymerization, which were due to the salts?insolubility in polar solvent. The amount of Ag ion replaced in the salt and the amount of the salt loaded on the silica significantly influenced the catalytic performance. Change in the Ag content of the supported silver salt altered the crystal phase composition of the silver tungstophoric acid and catalyst?s acid strength. The AgxH3-xPW/SiO2 catalyst had the highest acid strength and the highest polymerization activity when x=2.0. When the Ag2HPW loading was 30% (mass fraction), the catalyst exhibited the best dispersion and highest activity for the polymerization of tetrahydrofuran. Compared with the conventional silica supported heteropolyacid (HPW/SiO2) catalyst, the present 30%Ag2HPW/SiO2 displayed excel ent reusability, with its reactivity only slightly declining after 4 reuses. Through the introduction of the Ag ion, the stability of the novel supported 30%Ag2HPW/SiO2 was significantly improved and the obtained polymer product, polytetrahydrofuran, had a stable average molecular weight.