querjek - 8-6-2009 at 13:31
Hey all,
I know that permanganate can be used in the oxidative cleavage of an alkene, but can dichromate?
JohnWW - 8-6-2009 at 16:41
Except possibly under extreme conditions, dichromate(VI) does not seem to be a sufficiently powerful oxidant to cleave alkenes with oxidation. If it
were possible, the conditions required, more extreme than with permanganate, would probably result in undesired side-reactions.
OsO4 is a known alternative to permanganate(VII), but it is toxic and very expensive. Another known alternative is O3, but it is liable to form
explosive ozonide intermediates. Other possible sufficiently powerful alternatives to permanganate for the purpose are ferrate(VI), plumbate(IV),
bismuthate(V), and perxenate(VIII), as the alkali metal salts; and salts of Cu(III) and Ag(II)&(III). However, I have not heard of them being used
to any extent, and they are likely to be all more expensive than permanganate.
Perchlorate, chlorate, perbromate, or bromate, and some peroxides, may also do the job, but there would be a serious explosion hazard under the more
extreme conditions required than with permanganate. Another very likely possibility is salts of Ce(IV).
[Edited on 9-6-09 by JohnWW]
not_important - 8-6-2009 at 23:10
Hot, acidic, fairly concentrated dichromate will cleave carbon-carbon double bonds, although SFAIK the yields tend to be lower than using alkaline
permanganate. Work-up can also be a problem in some cases, traces of chromium sticking with some classes of carboxylic acids even through several
cycles of dissolution in base and precipitation with acid.
Panache - 10-6-2009 at 04:16
its ends up as a shocking, fucked-up mess, but probably works a little!