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Selective hydroxylation of small alkanes by the particulate methane monooxygenase

Citation

Zhu, Mei (1996) Selective hydroxylation of small alkanes by the particulate methane monooxygenase. Master's thesis, California Institute of Technology. http://resolver.caltech.edu/CaltechTHESIS:08212013-112742527

Abstract

The particulate methane monooxygenase (pMMO) catalyzes the oxidation of methane to methanol under ambient temperatures and pressures. Other small alkanes and alkenes are also substrates of this enzyme. We measured and compared the initial rate constants of oxidation of small alkanes (C1 to C5) catalyzed by pMMO. Both primary and secondary alcohols were formed from oxidation of n-butane and n-pentane. The alcohols produced from alkane oxidation can be further oxidized, probably by pMMO, to aldehydes and ketones. The apparent regioselectivity for n-butane and n-pentane is 100% 2-alcohols because the formation of primary alcohols is slower than further oxidation of these alcohols. The hydroxylation at the secondary carbons is highly stereoselective: (R)-alcohols are preferentially formed. The enantiomeric excess increases slightly with decreasing reaction temperature. The steric course of hydroxylation on primary carbons was also studied by using isotopically substituted ethane: (S)- or (R)-CH_3-CHDT, and (S)- or (R)-CD_3- CHDT and the reactions were found to proceed with 100% retention of configuration. A primary isotopic effect of k_H/k_D=5.0 was observed in these experiments.

Item Type:Thesis (Master's thesis)
Subject Keywords:Chemistry
Degree Grantor:California Institute of Technology
Division:Chemistry and Chemical Engineering
Major Option:Chemistry
Thesis Availability:Restricted to Caltech community only
Research Advisor(s):
  • Chan, Sunney I.
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 September 1995
Record Number:CaltechTHESIS:08212013-112742527
Persistent URL:http://resolver.caltech.edu/CaltechTHESIS:08212013-112742527
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:7931
Collection:CaltechTHESIS
Deposited By: Benjamin Perez
Deposited On:21 Aug 2013 21:12
Last Modified:21 Aug 2013 21:12

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