METHODE POUR LA PREPARATION DE SELS DE MONOESTERS DE L'ACIDE CARBONIQUE

METHOD FOR THE PREPARATION OF CARBONIC ACID MONOESTER SALTS

Abrégé anglais

METHOD FOR THE PREPARATION OF CARBONIC
ACID MONOESTER SALTS
ABSTRACT OF THE DISCLOSURE . -
A method is disclosed for the preparation of salts
of monoesters of the carbonic acid, the improvement con-
sisting in that the alcohols corresponding to the esters
are reacted with carbon dioxide and a compound of an alkali
metal or an alkaline earth metal. A distinct advantage
over the use of the alcoholates is obtained inasmuch as
the reaction is less violent, side-reactions are put aside
and the costs are lowered.

Revendications

The embodiments of the invention in which an exclusive
property or privilege is claimed are defined as follows:
1. A method for the preparation of salts of monoesters
of the carbonic acid having the formula:
<IMG>
wherein R is a lower alkyl or a lower alkenyl radical, n is 1 or 2
and Me is an alkali or alkaline earth metal, consisting in reacting
the corresponding alcohols with carbon dioxide and with a compound
of said metal having the formula MemXn wherein X is selected from
CO?, SO?, O= , OH- , BO?, S= , SH- , etc., m is 1, 2 or 3, and n is
as defined above.
2. A method according to claim 1, characterized in that
the reaction is carried out under a CO2 pressure ranging between
0 and 100 atmospheres.
3. A method according to claim 1, characterized
in that the reaction is carried out at a temperature comprised
between the freezing point and the boiling point temperature
of the employed alcohol.
4. A method according to claim 3, characterized
in that the reaction is carried out at a temperature
comprised between 0°C and 60°C.
5. A method according to claims 1, 2 or 3, characterized
in that the reaction is carried out in the presence of the alcohol
only as the reaction medium.
6. A method according to claims 1, 2 or 3, characterized
in that the reaction is carried out in the presence of a solvent
which is inert for the reaction.

Description

This invention relates to a method for the preparation
of salts of monoesters of the carboni~c acid, having the formula:
( RO -~C -~ )n Me
o
wherein R is a lower alkyl or a lower alkenyl radical, n is 1 or 2,
and Me is an alkali metal or an alkaline earth metal, the method
comprising the step of reacting the corresponding alcohols with
carbon dioxide and a compound of the metal having the formula
MemXn wherein X is selected from CO3, SO3, O , OH , BQ3, S ,
SH , etc. and m is 1, 2 or 3, n having the above indicated values.
The reaction, which takes place accordin~ to the
following patternO
MemXn + n CO2 + nROH ~ (ROCOO)nMe + HnXn Mem-l ,
simply takes place by causing a stream of CO2 to bubble through
a solution or a suspension of the selected salt in the alcohol
concerned, preferably with stirring. The pressure of CO2 can
be varied be-tween o and 100 atmospheres, whereas the temperature
is maintained between the freezing and the boiling point
temperature of the alcohol, preferably between 0C and ~0 C.
It is also possible to operate in the presence of
any solvent whatsoever providing that it is inert to the ends
of the subject reaction.
The salts of the carbonic acid monoesters can be
isolated by filtration, should they be insoluble, or precipitated
with an appropriate solvent, or, lastly, by evaporating of-f the
reaction medium.

Such ~alts can be u~ed in lieu of the co~re~ponding
alcoholates in the condensation reaction~ for example in the
condensatlons of aldehydes with activ~hydrogen-containing
molecules~ or of esters with ureas~ or also as the catalysts
in the aromatic ~ldehyde disproportionation reaction3.
A~ comparqd with the alcoholates, the ~alt~ as obta~ned
ascording to the present invention unfold~ in the above
indicated r~action~g a les~ dra~tic action~ the ~ide reactions
being limit~d and lower costs being achleYed.
The foregoing considerations will become more clearly
apparent from the scrutiny of the followin~ examples~ which are
intended tc elucidate the invention without ~ howerer~ limiting
the same thereby.
~XAMPLE
-
10 grams of a~hydrous K2~03 are ~lurried in 100 mls
an~vdrou~ metha~ol and a str~am of C02 f~r an amount slightly
over that whlch is absorbed is caused to bubble therethrough
with ~igorous stirring at 25C.
The reaction is both e~o~hermic and rapid and is completed
within 30 mlns. On completion of the absorption~ the residueg
KHC03, is collected on a ~ilter and the solution is evaporated
in a Yacuo ~ Th~re are obtained 8.5 grams of impure KOCOOCH
as it contains trace~ of KHC03.
EXAMPL~ ~
__
5.6 grams o~ CaO are ~lurried in 100 mls allyl alcohal
and stirred at 25C und~r a stream vf C02 A reaction which i~
both ex~thermic and rapid is obtained and is completed withir
35 mins. The bulky white precipitate is collected on a filter
under a nitro~en blanket, washed with ethyl et~er and dried in
a vacuo. There are ~btained 20 grams of Ca(OCOOCH2SH ~ CH2)2.

EXAMPLE 3
10 grams of NaOCOOCH3 ~0.1 mol) are dissolved in 100 mls
methanol: 16 grams of diethylma~onate and 6 grams urea are added
thereto The mixture is refluxed ~uring about & hours~ then is
dried in a vacuo to obtain 15 g~ams (approx.) of the sodium
salt oP the barbituriç acid. The l~tter~ upon hydrolysis with
2 N hydrochloric acid and extraction with ether gives 12 gra~s
of barbituric acid.
~
12 grams of benzyl cyani~e and 11 grams of benzaldehyde
with 10 gFam~ of NaCCOOCH3 are dissolved in 100 mls methanol and
refluxed during two hours The sodium carbonate is collectedg
hot, on a filter and the solvent is evaporated in a Yacuo. There
~r~ obtained 22 grams of phenrlcinnamonitrile~ having Na2C03 as
an impurity The pure produc~ i6 obtained by washing with
water.