Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acids and salts thereof
Reexamination Certificate
2000-03-14
2001-06-12
Killos, Paul J. (Department: 1623)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acids and salts thereof
C562S587000
Reexamination Certificate
active
06245940
ABSTRACT:
The subject matter of the present invention is a method of manufacturing an acid derivative of ose.
More precisely, its subject matter is a method of manufacturing an acid derivative of ose containing n carbon atoms on the hydrocarbonic chain, from an acid derivative of ose with n+1 carbon atoms having at least one a ketone function, or one of its salts, said method consisting in bringing said acid derivative of ose with n+1 carbon atoms into contact with hydrogen peroxide in a reaction medium without pH regulation.
In the sense of the invention, the terms are agreed to mean the following:
“acid derivative of ose containing at least one &agr; ketone function”: a mono- or dicarboxylic acid derivative of an aldose, containing a ketone function in &agr; of the acid function or functions,
“aldose”: an ose containing one aldehyde function, in particular a pentose or a hexose containing such a function, preferably chosen among xylose, arabinose, ribose, lyxose, glucose, mannose, galactose, maltose and lactose.
The method of the present invention makes it possible in particular to obtain, with excellent yield and selectivity, an aldonic acid from a 2-ketoaldonic acid of higher order.
The aldonic acids obtained by carrying out the method according to the invention are of great interest in themselves but are above all important intermediates in synthesis. In fact, a supplementary stage of hydrogenation makes it possible to easily obtain the corresponding alditols which are polyols which may be used in multiple applications, and in particular as non-cariogenic and low-calorie substitutes for saccharose.
These aldonic acids also constitute a raw material of interest for preparing biocompatible and/or biodegradable polymers which can be used in the food and medical fields.
It is while studying the already ancient method described in the patent JP 38.15610 of 1963 and taken up again by H. S. ISBELL et al. in the article of Carbohydrate research, 36, 1974, pages 283 to 291, which recommends the use of hydrogen peroxide on sodium salts of 2-ketoaldonic acids in a controlled reaction medium in order to obtain aldonic acids of lower order, that the Applicant company has developed this new method of manufacturing an acid derivative of ose.
This traditional method makes it possible to go, generally speaking, from the sodium salt of an aldonic acid with n+1 carbon atoms containing a ketone function in &agr;, to an acid derivative of ose with n carbon atoms, thanks to the oxygenated water in a reaction medium where the pH is kept constant by the addition of soda or hydrochloric acid.
The conversion of the sodium salt of 2-ketogluconic acid into the sodium salt of arabinonic acid can thus be realised according to this method.
However, the selectivity of said reaction remains relatively low, for significant quantities of the salts of erythronic acid and formic acid are co-produced with those of arabinonic acid. Furthermore, the regulation of the pH of the reaction leads to a significant, equimolar even, consumption of soda.
During an in-depth investigation of this reaction, the Applicant company discovered that if the reaction is conducted without any pH regulation, one can, in an unexpected manner, remarkably improve the selectivity of the reaction.
Indeed, none of the documents of the prior art quoted above either describes or suggests the use of hydrogen peroxide without pH regulation for the oxidative decarboxylation of an acid derivative of ose containing at least one ketone function in &agr;, or one of its salts.
Nothing in particular suggests that it is possible to increase considerably the selectivity of said reaction and thus the purity of the aldonic acid produced, which translates into a significant reduction of the production of co-products such as formic acid.
This new reaction thus has an important potential and there does not exist, to the knowledge of the applicant company, any equivalent reaction.
Thus, according to the invention, the method of manufacturing an acid derivative of ose containing n carbon atoms on the carbonic chain is characterised by the fact that an acid derivative of ose with n+1 carbon atoms containing at least one &agr; ketone function, and/or one of its salts, is brought into contact with hydrogen peroxide in a reaction medium without pH regulation.
The method according to the invention thus makes use of an acid derivative of ose with n+1 carbon atoms containing at least one &agr; ketone function, and/or one of its salts.
In the present invention, as indicated before, what is meant by acid derivative of ose with n+1 carbon atoms containing at least one &agr; ketone function is a mono- or dicarboxylic acid derivative of an aldose having at least one ketone function in &agr; position. This definition encompasses in particular:
the &agr;-ketoaldonic acids, which are monocarboxylic acids derived from aldoses by replacing the aldehyde group by a carboxy group, and replacing the secondary hydroxyl function in &agr; position by a ketone function, such as the &agr;-ketogluconic, &agr;-ketoglucoheptonic, &agr;-ketomannonic, &agr;-ketoidonic, &agr;-ketogulonic, &agr;-ketogalactonic, &agr;-ketolyxonic, &agr;-ketoxylonic, &agr;-ketoarabinonic, &agr;-ketoribonic, &agr;-ketomaltobionic and &agr;-ketolactobionic acids, of series D or L, and in particular the 2-keto-D-gluconic acid, the 2,5-diketo-D-gluconic acid and the 2-keto-L-gulonic acid,
the &agr;-ketoaldaric acids, which are dicarboxylic acids derived from aldoses by replacing the two terminal groups (CHO and CH
2
OH) by carboxy groups and replacing at least one secondary hydroxyl function in &agr; position by a ketone function, such as &agr;-ketoglucaric, &agr;-ketogalactaric, &agr;-ketoarabinaric and &agr;-ketoxylaric acids.
In the present invention, what is meant in particular by “salt of an acid derivative of ose” is a product chosen from the group comprising the alkaline and alkaline-earth salts of any acid derivative of ose such as defined before.
Thus, for example, the calcium and sodium salts of these acid derivatives of ose are perfectly suitable. These can be in particular calcium or sodium salts of 2-ketogluconic acid.
The acid derivatives of ose with n+1 carbon atoms containing at least one &agr; ketone function are obtained in known fashion by oxidation of the oses or of the corresponding acid derivatives of ose. This oxidation stage can be carried out either by a chemical process or by a microbiological process.
Within the framework of the present invention, there is no particular constraint in terms of the dry matter of the reaction medium. In practice, the method according to the invention is characterised by the fact that the acid derivative of ose with n+1 carbon atoms and having at least one ketone function in &agr;, or one of its salts, is provided in a quantity such that its concentration in the reaction medium is between 1 and 90% by weight, preferably between 10 and 50% by weight.
Only the constraints of minimum dry matter are imposed for obvious reasons of saving water evaporation and reducing the size of the reactors.
In the particular case of the calcium salt of the acid derivative of ose, it is recommended that too high an amount of dry matter be avoided. Indeed, it is known that the poor solubility of said calcium salt causes an increase in the viscosity of the reaction medium.
To the acid derivative of ose with n+1 carbon atoms containing at least one ketone function in &agr;, or one of its salts, is slowly added, with stirring, the hydrogen peroxide, preferably in the form of oxygenated water of a strength of 20 to 70%, preferably of the order of 35%, as will be exemplified below.
In a preferred manner according to the invention, the oxygenated water is added in an at the most equimolar quantity in relation to the acid derivative of ose with n+1 carbon atoms having at least one ketone function in &agr;.
Indeed, the Applicant company has not only shown that the decarboxylation reaction according to the invention does not require, contrary to
Chaudhry Mahreen
Henderson & Sturm LLP
Killos Paul J.
Roquette Freres
LandOfFree
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