| Abstract
| - The transformations of acetylene, chloroacetylene,1,1-dichloroethene (DCE), and cis- and trans-DCEmediated bycobalamin in the presence of titanium(III) citratewereinvestigated at pH 8 and 22 °C. Acetylenequantitativelyreacted to ethene via vinylcobalamin as the proposedintermediate. Chloroacetylene reacted to acetyleneandvinyl chloride. Proposed intermediates are ethynylcobalamin and vinylcobalamin, respectively. Theprincipalinitial reaction of chloroacetylene formedethynylcobalaminwhich decomposed to acetylene. The proposition forethynyl- and vinylcobalamin formation is based on fittingreaction models to kinetic data. Kinetic modelingsuggests half-lives for ethynyl- and vinylcobalamin of 1.4 and251 h, respectively. 1,1-Dichloroethene reacted toapproximately 20% volatiles (ethene, ethane, vinyl chloride,andacetylene) and 80% unidentified nonvolatile products.cis- and trans-DCE transformed slowly andproduced smallyields of vinyl chloride, ethene, and ethane.
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