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Factors affecting catalytic performance in yadh‐catalyzed reductions in non‐conventional media
Author(s) -
Nikolova P.,
Goldman H.,
Ward O. P.
Publication year - 1995
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.5450730411
Subject(s) - chemistry , heptane , benzaldehyde , butyl acetate , partition coefficient , solvent , solubility , ethyl acetate , octane , reaction rate constant , decane , catalysis , hexane , organic chemistry , kinetics , physics , quantum mechanics
The effects of parameters including water content, the amount of celite and the co‐factor regeneration system on reduction of benzaldehyde to benzyl alcohol by yeast alcohol dehydrogenase (YADH) immobilized on celite in non‐conventional media were investigated. Kinetic parameters (apparent) such as V max , K m , and k car for different organic solvents used (butyl acetate, hexane, heptane and i ‐octane) were determined. K m values for benzaldehyde increased as the solvent was varied in the following manner: butyl acetate < hexane < i ‐octane < heptane. The highest K m value (20.26 mmol/L) was noted in heptane and the lowest (3.24 mmol/L) in butyl acetate. The V max value in heptane was more than an order of magnitude higher than that in butyl acetate. Catalytic efficiencies (as expressed by k car /K m ) ranged from 0.703 × 10 −4 L/mol · s for hexane to 0.171 × 10 −4 L/mol · s for butyl acetate. In general, linear relationships were observed between k car /K m and the following solvent physico‐chemical constants: dielectric constant logarithm of the saturated molar solubility of water in the organic solvents, log S w/o , logarithm of partition coefficient of organic solvent in water/octanol two‐phase system, log P , Hildebrand solubility parameter, δ, and solvatochromism of pyridinium‐ N ‐phenoxide betaine dye, ET(30) .