Process for the preparation of secondary of tertiary dialkyl dicarbonate
AssigneeRhone-Poulenc Chimie
InventorsJean Desmurs, Serge Ratton
Life of this patent
Estimating the term…
Abstract
A process for the preparation of a secondary or tertiary dialkyl dicarbonate. An alkali metal salt of an alkyl pyrocarbonate is contacted with (CO).sub.n X.sub.2 wherein X is defined as a leaving group and n is an integer from 1 to 2, in the presence of a complexing agent.
Claims54
A process for the preparation of a secondary or tertiary dialkyl dicarbonate comprising,
- contacting an alkali metal salt of an alkyl carbonate half ester and (CO).sub.n X.sub.2 wherein X is a leaving group and n is an integer from 1 to 2, in the presence of an effective amount of a complexing agent with the proviso that if said (CO).sub.n X.sub.2 is phosgene, diphosgene or triphosgene and said complexing agent is a tertiary monoamine, or an amine selected from 1,4-diazabicyclo(2,2,2) octane, 1,8-diazabicyclo (5,4,0)undec-7-ene, hexamethylenetetramine, N-methylpiperidine or N-ethylpiperidine then the alkali metal is selected from sodium or lithium,
- wherein said complexing agent is selected from compounds which contain either at least one amine group or at least two ether groups with the proviso that if only ether groups are present, the complexing agent is tridentate.
The process according to claim 31, wherein the complexing agent is an oxygenated tertiary amine of the formula:
- N--[CHR.sub.1 ----CHR.sub.2 ----O----(CHR.sub.3 ----CHR.sub.4 ----O).sub.n ----R.sub.5 ].sub.3
- in which n is an integer greater than or equal to about 0 and less than or equal to about 10 (0.ltoreq.n.ltoreq.10), R.sub.1, R.sub.2, R.sub.3 and R.sub.4, which are identical or different, denote a hydrogen atom or an alkyl radical having from 1 to 4 carbon atoms and R.sub.5 denotes an alkyl or cycloalkyl radical having from 1 to 12 carbon atoms, a phenyl radical or a radical of formula --C.sub.m H.sub.2m --C.sub.6 H.sub.5, or C.sub.m H.sub.2m+1 --C.sub.6 H.sub.4 --, m being from about 1 to about 12.
A process for the preparation of di-tert-butyl dicarbonate comprising,
- contacting an alkali metal salt of di-tert-butyl carbonate half ester with phosgene, diphosgene or triphosgene, in the presence of an effective amount of a complexing agent with the proviso that if said complexing agent is a tertiarymonoamine, or an amine selected from 1,4-diazabicyclo (2,2,2) octane, 1,8-diazabicyclo (5,4,0)-undec-7-ene, hexamethylenetetramine, N-methylpiperidine or N-ethylpiperidine then the alkali metal is selected from sodium or lithium,
- wherein said complexing agent is selected from compounds which contain either at least one amine group or at least two ether groups with the proviso that if only ether groups are present, the complexing agent is tridentate.
The process of claim 39, wherein the aromatic solvent is toluene.
A process for the preparation of secondary or tertiarydialkyl dicarbonate comprising,
- contacting an alkali metal tertiary or secondary butylate with carbon dioxide and (CO).sub.n X.sub.2 in the presence of an effective amount of a complexing agent,
- wherein said complexing agent is selected from compounds which contain either at least one amine group or at least two ether groups with the proviso that is only ether groups are present, the complexing agent is tridentate,
- wherein the secondary or tertiary dialkyl dicarbonate is formed without the intermediate purification of a carbonate half ester reactant.
Dependencies are inferred from the claim text.