制备了100%SAPO-34,30%SAPO-34和介孔-SAPO-34三种不同类型的SAPO-34分子筛催化剂,并采用氮吸附、扫描电镜、X射线衍射和红外光谱等方法对催化剂进行了表征.三种催化剂的微孔结构、比表面积和总酸最近似,但具有不同的催化剂组成和次级结构.以1-己烯裂解为模型反应考察了三种催化剂的催化活性.对于30%SAPO-34催化剂,由于添加了粘结剂.其外表面酸性和扩散性能下降,导致催化活性降低:100%SAPO-34催化剂则具有较好的催化性能:介孔 SAPO-34催化剂次级结构的存在使其失活较慢,从而提高了原料的转化率.详细讨论了1-己烯催化裂解制丙烯的活性和选择性曲线,以进一步说明催化剂组成和结构的影响.
Three SAPO-34 catalysts, 100% SAPO-34, 30% SAPO-34, and meso-SAPO-34, with different bulk topologies were prepared. The catalysts were characterized by N_2 adsorption, scanning electron microscopy, X-ray diffraction, and infrared spectroscopy techniques. The pore size, total acidity, and internal cage structure of the catalysts were almost identical, but they had different bulk appearances. The role of the bulk topology/structure of the catalysts was studied using 1-hexene cracking. On 30% SAPO-34, the surface acidity and diffusion rate decreased due to blocking by binder, which adversely affected catalytic activity. 100% SAPO-34 gave better cracking ability and higher propylene selectivity because of suitable acid sites and effective shape selectivity, respectively. In order to study the effect of diffusion, meso-SAPO-34 was used. The different bulk structure gave different feed conversion and selectivity profiles. A superior control of the stereochemistry was observed in the cracking by the meso-SAPO-34 and 100% SAPO-34 catalysts, in which enhanced diffusion mass transport played an appreciable role. Most of the propylene was produced by the direct cracking pathway by the β-scission carbenium ion mechanism. Hydrogen transfer reactions became significant at higher conversions. Decreasing the residence time to a certain extend is an appropriate way to obtain high propylene yield and selectivity. Activity and selectivity patterns for 1-hexene cracking to propylene were compared to justify superior SAPO-34 topology for 1-hexene cracking to propylene.
参考文献
| [1] | Nawaz Z;Tang X P;Zhang Q;Wang D Z Wei F .[J].CATALYSIS COMMUNICATIONS,2009,10:1925. |
| [2] | Corma A;Melo F V;Sauvanaud L;Ortega F .[J].Catalysis Today,2005,107-108:699. |
| [3] | Nawaz Z;Wei F .[J]./籸f Eng Chem Res,2009,48:7442. |
| [4] | Wei Y X;Zhang D Z;Xu L;Liu Z M Su B L .[J].Catalysis Today,2005,1O6:84. |
| [5] | Nawaz Z;Qing S;Gao J;Tang X P Wei F.[J].Journal of Industrial and Engineering Chemistry,2009 |
| [6] | 李金哲,齐越,刘中民,刘广宇,常福祥.SAPO-34催化剂上反应条件对乙烯转化制丙烯的影响[J].催化学报,2008(07):660-664. |
| [7] | Nawaz Z;Tang X P;Wei F.[J].Brazilian Journal of Chemical Engineering,2009 |
| [8] | Houdek J M;Andersen J.[A].Malaysia:Kuala Lumpur,2005 |
| [9] | Nawaz Z;Tang X P;Wei F.[J].Korean Journal of Chemical Engineering,2009 |
| [10] | 魏飞,汤效平,周华群,Zeeshan Nawaz.增产丙烯技术研究进展[J].石油化工,2008(10):979-986. |
| [11] | Tang X D;Zhou H Q;Qian W Z;Wang D Z Jin Y Wei F .[J].Catalysis Letters,2008,125:380. |
| [12] | Zhou H;Wang Y;Wei F;Wang D Wang Z .[J].Applied Catalysis A:General,2008,348:135. |
| [13] | Smit B;Maesen T L M .[J].NATURE,2008,451:671. |
| [14] | Nawaz Z;Zhu J;Wei F.[A].Islamabad,Pakistan,2009 |
| [15] | Buchanan JS.;Haag WO.;Santiesteban JG. .MECHANISTIC CONSIDERATIONS IN ACID-CATALYZED CRACKING OF OLEFINS[J].Journal of Catalysis,1996(1):279-287. |
| [16] | Buchanan J S .[J].Applied Catalysis A:General,1998,171:57. |
| [17] | Niccum P K;Miller R B;Claude A M;Silverman M A.[A].San Francisco CA,1998 |
| [18] | Marchese L;Frache A;Gianotti E;Martra G Causa M Coluccia S .[J].Microporous and Mesoporous Materials,1999,30:145. |
| [19] | Lok B M;Messina C A;Patton R L;Gajek R T Cannan T R Flanigen E M .[J].Journal of the American Chemical Society,1984,106:6092. |
| [20] | Such X;Pang K.Zeolite Materials with Porous Chemicals[M].北京:科学出版社,2004:257. |
| [21] | Nawaz Z;Tang X P;Yu C;Wei F.[J].Arab J Sci Eng B,2009 |
| [22] | Zhu J;Vu C;Wang Y;Wei F.[J].Chemical Communications,2009:3282. |
| [23] | Schnabel K H;Fricke R;Girnus I;Jahn E,Loftier E,Parlitz B,Peuker C .[J].Journal of the Chemical Society,Faraday Transactions,1991,87:3569. |
| [24] | Xu L;Du A;Wei Y;Wang Y Yu Z He Y Zhang X Liu Z .[J].Microporous and Mesoporous Materials,2008,115:332. |
| [25] | Liu G;Tian P;Li J;Zhang D Zhou F Liu Z .[J].Microporous and Mesoporous Materials,2008,111:143. |
| [26] | Tan J;Liu Z;Bao X;Liu X Han X He C Zhai R.[J].Microporous and Mesoporous Materials,2002(z3):97. |
| [27] | Borade R B;Clearfield A .[J].Journal of Molecular Catalysis,1994,88:249. |
| [28] | Prakash A M;Unnikrishnan S .[J].Journal of the Chemical Society,Faraday Transactions,1994,90:2291. |
| [29] | Ashtekar S;Chilukuri S V V;Chakrabarty D K .[J].Journal of Physical Chemistry,1994,98:4878. |
| [30] | Sastre G;Lewis D W;Catlow C R A .[J].Journal of Physical Chemistry B,1997,101:5249. |
| [31] | Vomscheid R;Briend M;Peltre M J;Man P P Barthomeuf D .[J].Journal of Physical Chemistry,1994,98:9614. |
| [32] | Dumitriu E;Azzouz A;Hulea V .[J].Microporous Materials,1997,10:1. |
| [33] | Pu M;Li Z h;Gong Y J;Wu D Sun Y H .[J].Journal of Materials Science Letters,2003,22:955. |
| [34] | Abbot J;Wojciechowski B W .[J].Canadian Journal of Chemical Engineering,1985,63:462. |
| [35] | Kissin Y V .[J].Catalysis Review:Science and Engineering,2001,43:85. |
| [36] | Lukyanov D B .[J].Journal of Catalysis,1994,147:494. |
| [37] | Jung J S;Kim T J;Seo G .[J].Korean Journal of Chemical Engineering,2004,21:777. |
| [38] | den Hollander M A;Wissink M;Makkee M;Moulijn J A .[J].Applied Catalysis A:General,2002,223:85. |
| [39] | Feller A.;Zuazo I.;Guzman A.;Barth JO.;Lercher JA. .Common mechanistic aspects of liquid and solid acid catalyzed alkylation of isobutane with n-butene[J].Journal of Catalysis,2003(1/2):313-323. |
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