External heat is required and the reaction is performed in DMF with LiCl as catalyst. See C.E. Castrol et al. in The Journal of Organic Chemistry,
vol30 (1965) pp587solo - 1-12-2006 at 22:02
Reference Information
Cupric Halide Halogenations C. E. CASTRO, E. J. GAUGHAN, AND D. C. OWSLEY Journal of organic chemistry 1965, vol:30, iss:8, pg:2493
Abstract
Cupric bromide and cupric chloride in refluxing methanol and higher alcohols effect the following transforma- tions : p-alkoxylation a-halogenation
of carbonyl-conjugated vinyl groups, halogenation of isoleted double bonds, trans halogenation of internal acetylenes, and trihalogenation
of terminal acetylenes. In a reaction of undefined scope, ethanol is oxidatively halogenated with cupric bromide to dibromoacetaldehydediethyl
acetal. Kinetics of some representative transformations have been examined. Cupric bromide but not cupric chloride functions as a source of low
concentrations of halogen. Mechanisms for some of the conversions are suggested.
you should add peroxide to that mix it will give you a 78% yeild and the lithium is not nessacery plus it cost too much.guy - 28-12-2006 at 00:50
Quote:
Originally posted by Ephoton
you should add peroxide to that mix it will give you a 78% yeild and the lithium is not nessacery plus it cost too much.
Really? So add some H2O2 to the mixture?
What is the mechanism for that?Ephoton - 28-12-2006 at 22:12
sorry my mistake I missed out a reagent in my hast also needed is hydrochloric
acid
then this can be done wet as well. and the yield will be a bit lower than 78% sorry.
reflux 5 hours done. ratio is 2:1:1.3 tone acid peroxide only small amounts of copper are needed as a catylist sorry my mistake. still think its the
way to go though.
will post full refs when the time is right.
also needed is hydrochloric
acid