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The Methanol-Trimethoxyborane Azeotrope as a Solvent for Acid-Catalyzed Reactions. Methyl Esterification

M. M. Kreevoy ; Chemical Dynamics Laboratory, Department of Chemi stry, University of Minnesota, Minneapolis, Minn., 55455, U .S.A.
S. S. Kantner ; Chemical Dynamics Laboratory, Department of Chemi stry, University of Minnesota, Minneapolis, Minn., 55455, U .S.A.


Puni tekst: engleski pdf 2.511 Kb

str. 41-46

preuzimanja: 91

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Sažetak

Carboxylic acids UIIldergo a rapid and complete acid-catalyzed
methyl esterification in the methanol-trimethoxyborane azeotrope.
The reaction is first order in cariboxylic acid and first order in
strong acid catalyst. Rate constants are very similar to those in
methanol alone. These observations suggest that the mechanism
is the same as that in solvent, methanol-AAc 2. The reaction can be
made the basis of a convenient preparation of methyl esters. It has
been used to prepare methyl benzoate, methyl lactate, and the
methyl ester of phenylalanine. Acid-catalyzed acetal and ketal
formation in the azeotrope is fast but incomplete. Methyl etherification
of tertiary alcohols seems too limited, structurally, to be
generally useful. No acid-catalyzed addition of methanol to acetonitrile
or acrylonitrile could be observed.

Ključne riječi

Hrčak ID:

196410

URI

https://hrcak.srce.hr/196410

Posjeta: 195 *