- Email: [email protected]
Computerised information aids zeolite research
N16
thanum oxalate by decomposition in air. The period of the cycle, typically of the order of several minutes, varies with the reaction temperature, decreasing as the temperature is increased from 556 to 7oooC. No detailed explanation of this curious effect is offered. A different approach to the activation of methane is taken in the work of Gesser, Hunter and Das. In their paper on “The ozone sensitized oxidative conversion of methane to methanol and ethane to ethanol” they have demonstrated that the addition of small amounts of ozone is sufficient to sensitize the partial oxidation reaction. No detailed results are presented but at conversions of around 2% for methane or 4% for ethane reasonable selectivities to organic products are achieved. Methane produces both methanol and formaldehyde, while ethane gives ethene, ethane, methanol, formaldehyde, propane, acetaldehyde and ethanol. Further detailed work on alcohol formation is in progress. In a recent issue of Applied Catalysis A (90 (1992) NS) we were informed by M. Shelev that NO is not all bad. Perhaps, this paper from Gesser et al. is also an indication that ozone is not all bad either1 ROBBY BURCH
methylation of naphthaiene are found with CuAPO-5, PbAPO-5 and SAP05 operating at 6.0 MPa (cold pressure autoclave) and [email protected] workers discuss the apparent involvement of methyl radicals and comment on the various ratios observed for formation of P-methylnaphthalene and 1-methylnaphthalene. Blank runs in the absence of a catalyst reveal that some methylation occurs. Use of unmodified AIPO4-5 does not lead to any increase in conversion under the conditions used; only the modified sieves are active. Enzyme-like Enantioselective Catalysis Chiral catalytic cavities created on an aluminium-ion-doped silica gel surface using a chiral template show high enantioselective activity for 2,4-dinitrophenols. The surface cavities of silica modified by aluminium ions, introducing Lewis acid sites, act as a “footprint’ with a complementary structure to the template molecule. This imprinting method leads to distinctly different catalytic behaviour of the template towards enantiomeric substrates and gives an indication ofthe possibility of specific tailoring of enantioselective catalysts by using molecular imprinting methods (see J. Chem. Sot. Chem. Commun., (1992) 356).
Methylation by Methane
Direct methylation of aromatics by methane has been studied by Australian workers at the University of New South Wares and the CSIRO Division of Coat and Energy Technology at North Ryde. He et al. discuss the results in Energy and Fuels (6 (1992) 496). Emphasis has been placed on the use of EiAPO molecular sieves (El = Pb, Cu, Ni and St). highest activities for applied catalysis A: General
Computerised Information alds Zeollte Research ZEOPAK (see Smith, Hoyle &Johnson, Abstract No. RP192 in 9th IZC Extended Abstracts and Program, 1992) is a database bf information on X-ray powder diffraction patterns of zeolites available on VMS/VAX systems. Interactive computations allow identification, quantification Volume 92 No. 2 -
16 December 1992
N17
and characterisation of zeolites, both synthetic and natural, provided the XRD powder patterns are available. ZEOFILE (see Newsam, Deem and Treaty, Abstract No. 121 in Recent Research Reports of the 8th IZC, 1989 and Newsam and Treaty, Abstract No. RP193 in the 9th IZC Extended Abstracts and Program, 1992) is an exhaustive collection available for Mackintosh systems of the topology, structure, crystallographic information and physico-chemical properties of 85 structure types given in the publication “Atlas of zeolite structure types” by Meier and Olson. Further, the possibility of simulating diffraction patterns and the facility to export the textual and graphical information to word-processors and other files are added advantages of this package. ZEOBASE (see Bauer and Fischer, Abstract No. RP216 in the 9th IZC Extended Abstracts and Program, 1992) is a package for IBM-PC (AT286) systems that contains information on the crystal structures of nearly 1366 entries of zeolite and zeolitelike materials. Retrieval of structural informatioaispossible with several search procedures and abstract ideas on the structure of zeolites are easily visualised. The powder diffraction patterns and molecular models of zeolites can be displayed on the screen as well as outputted to either printer or plotter. ZEOSYN, created by the author of the present item and his colleagues (lyer, Selvam and Vetrivel) comprises information for IBM-PC (AT286) systems on the synthesis procedure and catalytic properties as well as the physico-chemical properties of the 85 zeolite structure types given in “Atlas of zeolite structure types’ by Meier and Olson. Again, this information can be
applied catalysis A: General
extracted from the data-base by answering user-friendly question menus. Additionally, the author and his colleagues are building a ‘rule-based’ expert system to obtain an optimised synthesis route for a given zeoliie. This route will be computerbased on well-documented synthesis procedures and/or based on well-established correlations (such as inverse proportionality between temperature and time of crystallisation, direct proportionali between time of crystallisation and the density of phase formed, etc.). Earlier reports of applying artificial intelligence and expert systems for catalyst design are the inspiration for the ZEOSYN package. Examples of the reports mentioned are DECADE (Design Expert for CAtaiyst DEvelopment) by Alcantara et al., Comput. Chem. Eng., 12 (1968) 923, and ARCADE (ARtiiicial Intelligence system for CAtaiyst DEsign) by Hattori et al., Shokubai, 31 (1989) 9. The value of the vast amount of information available in the literature is increased when it is put together systematically and utilised effectively. R. VETRIVEL
Catalysis Pipeline
Many readers will be familiar with the Catalysis Pipeline, a free Elsevier publication that lists all forthcoming papers, to be published in Applied Catalysis, Journal of Molecular Catalysis and Reaction Kinetics and Catalysis Letters, as well as forthcoming issues of Catalysis Today and the book series Studies in Surface Science and Catalysis. The Catalysis Pipeline is now in its second year and, apparently, this service is highly appreciated and thousands of readers have subscribed to it. Yet the Volume 92 No. 2 -
16 December 1992
thanum oxalate by decomposition in air. The period of the cycle, typically of the order of several minutes, varies with the reaction temperature, decreasing as the temperature is increased from 556 to 7oooC. No detailed explanation of this curious effect is offered. A different approach to the activation of methane is taken in the work of Gesser, Hunter and Das. In their paper on “The ozone sensitized oxidative conversion of methane to methanol and ethane to ethanol” they have demonstrated that the addition of small amounts of ozone is sufficient to sensitize the partial oxidation reaction. No detailed results are presented but at conversions of around 2% for methane or 4% for ethane reasonable selectivities to organic products are achieved. Methane produces both methanol and formaldehyde, while ethane gives ethene, ethane, methanol, formaldehyde, propane, acetaldehyde and ethanol. Further detailed work on alcohol formation is in progress. In a recent issue of Applied Catalysis A (90 (1992) NS) we were informed by M. Shelev that NO is not all bad. Perhaps, this paper from Gesser et al. is also an indication that ozone is not all bad either1 ROBBY BURCH
methylation of naphthaiene are found with CuAPO-5, PbAPO-5 and SAP05 operating at 6.0 MPa (cold pressure autoclave) and [email protected] workers discuss the apparent involvement of methyl radicals and comment on the various ratios observed for formation of P-methylnaphthalene and 1-methylnaphthalene. Blank runs in the absence of a catalyst reveal that some methylation occurs. Use of unmodified AIPO4-5 does not lead to any increase in conversion under the conditions used; only the modified sieves are active. Enzyme-like Enantioselective Catalysis Chiral catalytic cavities created on an aluminium-ion-doped silica gel surface using a chiral template show high enantioselective activity for 2,4-dinitrophenols. The surface cavities of silica modified by aluminium ions, introducing Lewis acid sites, act as a “footprint’ with a complementary structure to the template molecule. This imprinting method leads to distinctly different catalytic behaviour of the template towards enantiomeric substrates and gives an indication ofthe possibility of specific tailoring of enantioselective catalysts by using molecular imprinting methods (see J. Chem. Sot. Chem. Commun., (1992) 356).
Methylation by Methane
Direct methylation of aromatics by methane has been studied by Australian workers at the University of New South Wares and the CSIRO Division of Coat and Energy Technology at North Ryde. He et al. discuss the results in Energy and Fuels (6 (1992) 496). Emphasis has been placed on the use of EiAPO molecular sieves (El = Pb, Cu, Ni and St). highest activities for applied catalysis A: General
Computerised Information alds Zeollte Research ZEOPAK (see Smith, Hoyle &Johnson, Abstract No. RP192 in 9th IZC Extended Abstracts and Program, 1992) is a database bf information on X-ray powder diffraction patterns of zeolites available on VMS/VAX systems. Interactive computations allow identification, quantification Volume 92 No. 2 -
16 December 1992
N17
and characterisation of zeolites, both synthetic and natural, provided the XRD powder patterns are available. ZEOFILE (see Newsam, Deem and Treaty, Abstract No. 121 in Recent Research Reports of the 8th IZC, 1989 and Newsam and Treaty, Abstract No. RP193 in the 9th IZC Extended Abstracts and Program, 1992) is an exhaustive collection available for Mackintosh systems of the topology, structure, crystallographic information and physico-chemical properties of 85 structure types given in the publication “Atlas of zeolite structure types” by Meier and Olson. Further, the possibility of simulating diffraction patterns and the facility to export the textual and graphical information to word-processors and other files are added advantages of this package. ZEOBASE (see Bauer and Fischer, Abstract No. RP216 in the 9th IZC Extended Abstracts and Program, 1992) is a package for IBM-PC (AT286) systems that contains information on the crystal structures of nearly 1366 entries of zeolite and zeolitelike materials. Retrieval of structural informatioaispossible with several search procedures and abstract ideas on the structure of zeolites are easily visualised. The powder diffraction patterns and molecular models of zeolites can be displayed on the screen as well as outputted to either printer or plotter. ZEOSYN, created by the author of the present item and his colleagues (lyer, Selvam and Vetrivel) comprises information for IBM-PC (AT286) systems on the synthesis procedure and catalytic properties as well as the physico-chemical properties of the 85 zeolite structure types given in “Atlas of zeolite structure types’ by Meier and Olson. Again, this information can be
applied catalysis A: General
extracted from the data-base by answering user-friendly question menus. Additionally, the author and his colleagues are building a ‘rule-based’ expert system to obtain an optimised synthesis route for a given zeoliie. This route will be computerbased on well-documented synthesis procedures and/or based on well-established correlations (such as inverse proportionality between temperature and time of crystallisation, direct proportionali between time of crystallisation and the density of phase formed, etc.). Earlier reports of applying artificial intelligence and expert systems for catalyst design are the inspiration for the ZEOSYN package. Examples of the reports mentioned are DECADE (Design Expert for CAtaiyst DEvelopment) by Alcantara et al., Comput. Chem. Eng., 12 (1968) 923, and ARCADE (ARtiiicial Intelligence system for CAtaiyst DEsign) by Hattori et al., Shokubai, 31 (1989) 9. The value of the vast amount of information available in the literature is increased when it is put together systematically and utilised effectively. R. VETRIVEL
Catalysis Pipeline
Many readers will be familiar with the Catalysis Pipeline, a free Elsevier publication that lists all forthcoming papers, to be published in Applied Catalysis, Journal of Molecular Catalysis and Reaction Kinetics and Catalysis Letters, as well as forthcoming issues of Catalysis Today and the book series Studies in Surface Science and Catalysis. The Catalysis Pipeline is now in its second year and, apparently, this service is highly appreciated and thousands of readers have subscribed to it. Yet the Volume 92 No. 2 -
16 December 1992