采用浆液浸渍法制备了小同载体负载的Cu_2(OH)_3Cl催化剂,考察了催化剂对甲醇氧化羰基化合成碳酸二甲酯(DMC)反应的催化性能.结果表明,各载体负载的Cu_2(OH)_3Cl催化剂活性均高于传统的负载CuCl_2催化剂;以比表面积较大的活性炭(AC)为载体的催化剂活性最高.以Cu_2(OH)_3Cl/AC(w(Cu)=18.71%)为催化剂时,甲醇转化率、DMC选择性和DMC时宅收率可分别达到6.93%,67.3%和139.1mg/(g·h);其催化性能比较稳定,反应60h后其催化活性略有下降.通过CO程序升温脱附、X射线衍射、X射线光电子能谱和扫描电镜等技术对催化剂进行了表征.结果表明,在反应过程中催化剂的活性物种Cu_2(OH)_3Cl的晶粒逐渐团聚、长大,并且转化为CuCl_2和CuO;同时,新鲜催化剂中唯一的Cu~Ⅱ物种部分转化为Cu~Ⅰ物种.
Supported Cu_2(OH)_3Cl catalysts were prepared by the slurry impregnantion method and used in MeOH oxidative carbonylation to dimethyl carbonate (DMC). The catalytic activity of Cu_2(OH)_3Cl supported on various supports was higher than that of supported CuCl_2, and active carbon (AC) was the suitable support because of its larger specific surface area. Cu_2(OH)_3Cl/AC (w(Cu) =18.71%) exhibited excellent catalytic performance. MeOH conversion, DMC selectivity, and DMC space time yield were 6.93%, 67.3%, and 139.13 mg/(g·h), respectively, and the catalyst was more stable. The supported catalysts were characterized by CO-temperature programmed desorption, X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy, showing that the higher dispersion of Cu_2(OH)_3Cl in Cu_2(OH)_3Cl/AC was getting worse and transformed to CuCl_2 and CuO during the reaction, resulting in the decrease of catalytic activity. The unique Cu~Ⅱ species in the fresh catalyst transferred into Cu~Ⅰ species partially during the reaction.
参考文献
[1] | Delledonne D;Rivetti F;Romano U .[J].Applied Catalysis A:General,2001,221:241. |
[2] | Romano U;Tesei R;Mauri M M;Rebora P .[J].Lnd Eng Chem Prod Res Dev,1980,19:396. |
[3] | Tomishige K;Sakaihori T;Sakai S;Fujimoto K .[J].Applied Catalysis A:General,1999,181:95. |
[4] | Zhang Y H;Drake I J;Briggs D N;Bell A T .[J].Journal of Catalysis,2006,244:219. |
[5] | Zhang Y H;Briggs D N;de Smit E;Bell A T .[J].Journal of Catalysis,2007,251:443. |
[6] | Richter M;Fait MJG;Eckelt R;Schreier E;Schneider M;Pohl MM;Fricke R .Oxidative gas phase carbonylation of methanol to dimethyl carbonate over chloride-free Cu-impregnated zeolite Y catalysts at elevated pressure[J].Applied Catalysis, B. Environmental: An International Journal Devoted to Catalytic Science and Its Applications,2007(3/4):269-281. |
[7] | Richter M;Fait MJG;Eckelt R;Schneider M Radnik J Heidemann D Fricke R .[J].Journal of Catalysis,2007,245:11. |
[8] | 李忠,孟凡会,任军,郑华艳,谢克昌.CuCl/SiO2-Al2O3催化剂的表面结构及甲醇氧化羰基化催化性能[J].催化学报,2008(07):643-648. |
[9] | 李忠,黄海彬,谢克昌.Cu(I)/SO2-4/ZnO和Cu(I)/S2O2-8/ZnO催化剂的制备与表征[J].高等学校化学学报,2008(08):1609-1615. |
[10] | Han MS.;Suh I.;Kim HS.;Ahn BS.;Hong SI.;Lee BG. .Synthesis of dimethyl carbonate by vapor phase oxidative carbonylation of methanol over Cu-based catalysts[J].Journal of molecular catalysis, A. Chemical,2001(1/2):225-234. |
[11] | Han M S;Lee B G;Ahn B S;Kim H S Moon D J Hong S I .[J].Journal of Molecular Catalysis A:Chemical,2003,203:137. |
[12] | 宋军超,赵天生,杜彦忠.用于甲醇直接气相氧化羰基化的负载铜催化剂[J].催化学报,2006(05):386-390. |
[13] | Wang Y J;Zhao X Q;Yuan B G;Zhang B Ch Cong J Sh .[J].Applied Catalysis A:General,1998,171:255. |
[14] | 杨平,曹勇,包信和,戴维林,范康年.助剂对合成碳酸二甲酯用活性炭负载Wacker催化剂结构和性能的影响[J].催化学报,2004(12):995-999. |
[15] | Yang P;Cao Y;Dai W L;Deng J F Fan K N .[J].Applied Catalysis A:General,2003,243:323. |
[16] | 王少成,曹勇,杨平,胡建国,吴东,孙予罕,邓景发.TBAB修饰的负载型Wacker催化剂催化甲醇羰基化合成碳酸二甲酯[J].高等学校化学学报,2002(12):2363-2365. |
[17] | Han MS.;Lee BG.;Ahn BS.;Moon DJ.;Hong SI. .Surface properties of CuCl2/AC catalysts with various Cu contents: XRD, SEM, TG/DSC and CO-TPD analyses[J].Applied Surface Science: A Journal Devoted to the Properties of Interfaces in Relation to the Synthesis and Behaviour of Materials,2003(1/4):76-81. |
[18] | Jiang R X;Wang Y J;Zhao X Q;Wang Sh F Jin Ch Q Zhang Ch F .[J].Journal of Molecular Catalysis A:Chemical,2002,185:159. |
[19] | King ST. .REACTION MECHANISM OF OXIDATIVE CARBONYLATION OF METHANOL TO DIMETHYL CARBONATE IN CU-Y ZEOLITE[J].Journal of Catalysis,1996(2):530-538. |
- 下载量()
- 访问量()
- 您的评分:
-
10%
-
20%
-
30%
-
40%
-
50%