CAJ | 학술논문

通过浸渍法分别制备了硅胶(SiO2)、全硅MCM-41介孔分子筛负载ZrO2催化剂，考察其在以异丙醇为氢源，苯乙酮的氢转移反应中的催化性能，并与纯ZrO2进行对比，同时对各催化剂进行XRD、N2吸附-脱附、XPS、吡啶原位吸附红外等表征分析。结果表明：与纯 ZrO2相比，负载型催化剂活性明显增加，归因于 ZrO2与载体发生强相互作用，形成Si-O-Zr键，使催化剂表面的Zr-OH数目显著增加，出现B酸中心，且L酸中心强度增强。ZrO2/MCM-41的催化活性优于ZrO2/SiO2，可归因为前者中ZrO2的分散程度较高。ZrO2/MCM-41的最佳ZrO2负载量为5%(wt)；最佳反应时间8 h；最佳异丙醇和苯乙酮摩尔比为10：1。苯乙酮含吸电子取代基后转化率升高，而含供电子取代基后转化率降低。5%ZrO2/MCM-41的催化活性随重复使用次数增加而逐渐降低。
통과침지법분별제비료규효(SiO2)、전규MCM-41개공분자사부재ZrO2최화제，고찰기재이이병순위경원，분을동적경전이반응중적최화성능，병여순ZrO2진행대비，동시대각최화제진행XRD、N2흡부-탈부、XPS、필정원위흡부홍외등표정분석。결과표명：여순 ZrO2상비，부재형최화제활성명현증가，귀인우 ZrO2여재체발생강상호작용，형성Si-O-Zr건，사최화제표면적Zr-OH수목현저증가，출현B산중심，차L산중심강도증강。ZrO2/MCM-41적최화활성우우ZrO2/SiO2，가귀인위전자중ZrO2적분산정도교고。ZrO2/MCM-41적최가ZrO2부재량위5%(wt)；최가반응시간8 h；최가이병순화분을동마이비위10：1。분을동함흡전자취대기후전화솔승고，이함공전자취대기후전화솔강저。5%ZrO2/MCM-41적최화활성수중복사용차수증가이축점강저。
The catalysts of zirconia supported on silica gel and siliceous MCM-41 mesoporous materials, respectively, were prepared by the impregnation method. Their catalytic activities in the Meerwein-Ponndorf-Verley (MPV) reduction of acetophenone with α-propanol as hydrogen donor were investigated, and compared to that of using hydrous zirconia as catalyst. At the same time, these samples were characterized by XRD, N2 adsorption-desorption, XPS, FT-IR spectra of adsorbed pyridine methods, respectively. The results show that loading zirconia on MCM-41 or silica gel can significantly improved its catalytic activity. The results show that the catalytic activity can be significantly improved by loading Zirconia on MCM-41 or silica gel, which causes the occurance of the strong interaction between Zirconia and supports, results in the formation of Si-O-Zr bonds and consequently causes a marked increase of the amount of the Zr-OH group on the catatyst surface, the appearance of Bronzed acid sites and the strengthening of Lewis acidity. ZrO2/MCM-41 shows better catalytic activity than ZrO2/SiO2 due to the highly dispersion of ZrO2 on MCM-41. The best loading amount of ZrO2 in ZrO2/MCM-41 is 5%(wt). The reaction can be essentially completed after 8 h. The best mole ratio of 2-propanol to acetophenone is 10:1. Compared with acetophenone, the conversion of acetophenone with electron-withdrawing group linked to the aromatic ring is higher, while the conversion of acetophenone with electron-releasing group linked to aromatic ring is lower. When the 5%ZrO2/MCM-41 was reused, gradually dropping catalytic activity was observed.