AlMePO-beta: inclusion and thermal removal of structure directing agent and the topotactic reconstructive transformation to its polymorph AlMePO-alpha

被引:50
作者
Carter, VJ
Wright, PA
Gale, JD
Morris, RE
Sastre, E
PerezPariente, J
机构
[1] UNIV ST ANDREWS,SCH CHEM,ST ANDREWS KY16 9ST,FIFE,SCOTLAND
[2] UNIV LONDON IMPERIAL COLL SCI TECHNOL & MED,DEPT CHEM,LONDON SW7 2AY,ENGLAND
[3] CSIC,INST CATALISIS & PETR QUIM,CANTO BLANCO 28049,MADRID,SPAIN
关键词
D O I
10.1039/a703244g
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The microporous aluminium methylphosphonate-beta (AlMePO-beta), prepared in the presence of 1,4-dioxane with the composition per formula unit of Al-2(PO3CH3)(3) . 0.25C(4)H(8)O(2), loses dioxane molecules in two steps upon heating in an inert gas. Further heating in the presence of water vapour results in topotactic reconstructive transformation into the closely related a polymorph; under water vapour partial pressures of ca. 25 Torr, the transformation proceeds close to completion at temperatures in excess of 460 degrees C. Calculation of the lattice energies of the two AlMePO polymorphs shows the a form to be more stable by 12.6 kJ mol(-1) per Al-2(PO3CH3)(3) formula unit, and confirms the thermodynamic reason for the transformation. Close comparison of the structures reveals that the main difference lies in the position of Al(4) in the beta structure, and a mechanistic pathway is suggested and illustrated by which the aluminium migrates following Al-O-P bond hydrolysis and subsequent bond remaking to give rise to the alpha polymorph. The branching nature of the propagation step of the migration, which also results in methylphosphonate group rotations, explains how transformation might occur rapidly in a concerted fashion. A role for the water in catalysing the transformation is proposed.
引用
收藏
页码:2287 / 2292
页数:6
相关论文
共 15 条
[1]   BOND-VALENCE PARAMETERS OBTAINED FROM A SYSTEMATIC ANALYSIS OF THE INORGANIC CRYSTAL-STRUCTURE DATABASE [J].
BROWN, ID ;
ALTERMATT, D .
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE, 1985, 41 (AUG) :244-247
[2]   THE DEVELOPMENT AND USE OF QUANTUM-MECHANICAL MOLECULAR-MODELS .76. AM1 - A NEW GENERAL-PURPOSE QUANTUM-MECHANICAL MOLECULAR-MODEL [J].
DEWAR, MJS ;
ZOEBISCH, EG ;
HEALY, EF ;
STEWART, JJP .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1985, 107 (13) :3902-3909
[3]  
GALE JD, 1996, GEN UTILITY LATTICE
[4]  
GALE JD, 1997, IN PRESS FARADAY DIS, V106
[5]   Computational studies of aluminum phosphate polymorphs [J].
Henson, NJ ;
Cheetham, AK ;
Gale, JD .
CHEMISTRY OF MATERIALS, 1996, 8 (03) :664-670
[6]   SYNTHESIS OF THE FIRST MICROPOROUS ALUMINUM PHOSPHONATE WITH ORGANIC GROUPS COVALENTLY BONDED TO THE SKELETON [J].
MAEDA, K ;
KIYOZUMI, Y ;
MIZUKAMI, F .
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION IN ENGLISH, 1994, 33 (22) :2335-2337
[7]   ALMEPO-ALPHA - A NOVEL OPEN-FRAMEWORK ALUMINUM METHYLPHOSPHONATE WITH ORGANO-LINED UNIDIMENSIONAL CHANNELS [J].
MAEDA, K ;
AKIMOTO, J ;
KIYOZUMI, Y ;
MIZUKAMI, F .
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 1995, 34 (11) :1199-1201
[8]   STRUCTURE OF ALUMINUM METHYLPHOSPHONATE, ALMEPO-BETA, WITH UNIDIMENSIONAL CHANNELS FORMED FROM LADDER-LIKE ORGANIC-INORGANIC POLYMER-CHAINS [J].
MAEDA, K ;
AKIMOTO, J ;
KIYOZUMI, Y ;
MIZUKAMI, F .
JOURNAL OF THE CHEMICAL SOCIETY-CHEMICAL COMMUNICATIONS, 1995, (10) :1033-1034
[9]   LITTLE ENERGETIC LIMITATION TO MICROPOROUS AND MESOPOROUS MATERIALS [J].
NAVROTSKY, A ;
PETROVIC, I ;
HU, YT ;
CHEN, CY ;
DAVIS, ME .
MICROPOROUS MATERIALS, 1995, 4 (01) :95-98
[10]   STRUCTURE DETERMINATION AND RIETVELD REFINEMENT OF ALUMINOPHOSPHATE MOLECULAR-SIEVE ALPO4-8 [J].
RICHARDSON, JW ;
VOGT, ETC .
ZEOLITES, 1992, 12 (01) :13-19