Structural organization of phosphorus titanate oxides prepared by the alkoxo method and their catalytic activity in ethylene glycol oxyethylation |
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Authors: | Kozlovskii R A Yushchenko V V Kitaev L E Bukhtenko O V Voloshchuk A M Vasil"eva L N Tsodikov M V |
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Institution: | (1) D. I. Mendeleev Russian Chemico-Technological University, 9 Miusskaya pl., 125047 Moscow, Russian Federation;(2) Department of Chemistry, M. V. Lomonosov Moscow State University, Leninskie Gory, 119899 Moscow, Russian Federation;(3) Russian Academy of Sciences, A. V. Topchiev Institute of Petrochemical Synthesis, 29 Leninsky prosp., 119991 Moscow, Russian Federation;(4) Russian Academy of Sciences, Institute of Physical Chemistry, 31 Leninsky prosp., 119991 Moscow, Russian Federation;(5) Department of Chemistry, Moscow State Pedagogical University, 1 ul. M. Pirogovskaya, 117915 Moscow, Russian Federation |
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Abstract: | The relationship of the structural organization and acid-base properties of the surface of phosphorus titanate oxides prepared from tetra-n-butoxytitanium and phosphorous esters with the catalytic activity and selectivity of these materials in ethylene glycol oxyethylation was studied. Single-phase phosphorus-containing oxides synthesized from 2-diethylamido-4-methyl-1,3,2-dioxophosphorinane and diphenyl(methano)phosphocane have strong surface aprotic acid sites and exhibit high catalytic activity with respect to oxyethylation and a record-breaking selectivity in the formation of the lower homolog, diethylene glycol. The last-mentioned fact is a consequence of the sieve effect exerted by the homogeneous porous structure of supermicropores (8—10 ) of the oxides. An increase in the concentration of the strong acid sites ( 130 kJ mol–1) on the oxide surface enhances the catalytic activity. On the basis of the temperature programmed desorption of ammonia and CO2 and kinetic measurements, a concerted acid-base mechanism was proposed for the catalytic addition of ethylene oxide to ethylene glycol on the phosphorus-titanate surface. |
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Keywords: | alkoxo method tetra-n-butoxytitanium phosphorous esters structure porosity X-ray diffraction temperature programmed desorption ammonia carbon dioxide regional rate method catalysis oxyethylation of ethylene glycol catalytic activity selectivity |
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