Enantioselection using modified zeolite catalysts

• Published in: Journal of molecular catalysis. A, Chemical Chemical, 1996, Vol.107 (1), p.291-295
• Main Authors: Feast, Saskia, Bethell, Donald, Bulman Page, Philip C., King, Frank, Rochester, Colin H., Siddiqui, M.Rafiq H., Willock, David J., Hutchings, Graham J.
• Format: Article
• Language: English
• Subjects: Catalysis; Catalytic reactions; Chemistry; Exact sciences and technology; General and physical chemistry; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
• ISSN: 1381-1169; 1873-314X
• DOI: 10.1016/1381-1169(95)00223-5

The proton form of zeolite Y was modified with R-1,3-dithiane-1-oxide at a loading of one molecule per supercage to create a chiral acid catalyst. The enantiomeric discrimination of this catalyst was demonstrated using the dehydration of the separate enantiomers of butan-2-ol and over the temperature range investigated the S-enantiomer was always more reactive. This catalyst system was then studied using computational simulation methods. The lowest energy structures for the enantiomers of butan-2-ol docked into a model of the modified zeolite were calculated and it was found that the binding energy for the S-enantiomer is 64.7 kJ mol − and that for the R-enantiomer is 48.3 kJ mol −. This difference in the adsorption of the two enantiomers is considered to be the origin of the enhanced reactivity of the S-enantiomer.