Organic compounds -- part of the class 532-570 series – Organic compounds – Carbohydrates or derivatives
Reexamination Certificate
2000-02-29
2002-11-05
Padmanabhan, Sreeni (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carbohydrates or derivatives
Reexamination Certificate
active
06476217
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The subject matter of the present invention is a method of manufacturing an aldose or an aldose derivative.
More precisely, its subject matter is a method of manufacturing an aldose or an aldose derivative containing n carbon atoms on the hydrocarbonic chain, from an acid derivative of saccharide with n+1 carbon atoms having at least one &agr;-hydroxy acid unit, and/or one of its salts, this method consisting in bringing said acid derivative of saccharide into contact with hydrogen peroxide (hydrogen peroxide) in the presence of at least one metal salt chosen from the group consisting of tungsten and molybdenum, in an aqueous phase.
In the sense of the present invention, the terms are agreed to mean the following:
“aldose”: saccharide containing one aldehyde function, in particular a tetrose or a pentose containing such a function, preferably chosen from erythrose, threose, ribose, xylose and arabinose;
“aldose derivative”: more particularly a uronic acid (monocarboxylic acid derived from an aldose by replacing the CH
2
OH group with a COOH group);
“acid derivative of saccharide containing at least one &agr;-hydroxy acid unit”: a mono- or dicarboxylic acid derived from an aldose, containing one CHOH function in &agr; of the acid function or functions and being in free and/or lactonised form.
The method of the present invention makes it possible to obtain, with excellent selectivity, an aldose from an aldonic acid, or a uronic acid from an aldaric acid, in free or lactonised form, and/or in the form of salt(s).
The aldoses obtained by carrying out the method according to the invention are of great interest in themselves but would particularly be very important intermediate chemicals in synthesis if it were to come about that they could be produced in great quantity and at a low cost. In fact, a complementary stage of hydrogenation of these aldoses makes it possible easily to obtain the corresponding alditols which are all polyols able to be used in multiple applications, and particularly as substitutes for saccharose which are low-calorie and non-cariogenic.
The uronic acids obtained by carrying out the method according to the invention, as polyhydroxycarboxylic acids, have sequestering properties capable of being exploited in the field of cements, mortars or concretes in which such acids have been suggested as agents to retard setting, or even in the field of detergency where these acids have been proposed for cleaning articles made of glass or metal, or as additives for detergents.
2. Description of the Related Art
It is in studying the method explained by RUFF, almost a century ago (Ber. 32, 3674, (1889); 33, 1799 (1900)) that the Applicant has perfected this new method of manufacturing an aldose or an aldose derivative, by a chemical process, from an acid derivative of saccharide or from its salts.
RUFF's method makes it possible to pass, generally speaking, from an aldonic acid containing n carbons to an aldose containing (n−1) carbons thanks to the combined action of ferric ions and of hydrogen peroxide. However the yields of aldose are very mediocre.
The conversion of gluconic acid into D-arabinose can thus be realized according to this method.
Some improvements have subsequently been provided by R. C. Hockett and C. S. Hudson (J. Amer. Chem. Soc. 56, 1632-1633, (1934) and ibid. 72, 4546, (1950)) and by the inventors of U.S. Pat. No. 3,755,294. Yields of 60% of arabinose starting with gluconic acid are described there. Progress has also been made by V. Bilik (CZ—232647, (1983)), using cupric ions (Cu (II)) as catalysts. Yields of the order of 70% have been reached after laborious purification. Necessary in particular are the addition of ion exchange resins and column chromatography.
Identical results have been obtained recently with a mixture of ferric and ferrous ions as catalysts (CZ—279002, (1994)).
Finally, in particular conditions, document EP-A 0.716.067 reports yields of 78% of certain aldoses, but the technique also requires ion exchange chromatography in order to eliminate the impurities.
During an in-depth investigation of Ruff's reaction, the Applicant discovered that, if the reaction is catalyzed by selected concentrations of tungsten or molybdenum salts (both group VI metals), it is, unexpectedly, possible to resolve the problems of selectivity which accompanied prior methods and prevented their development.
Tungsten complexes are well cited as oxidation catalysts of secondary alcohols in ketones in the presence of hydrogen peroxide (S. E. Jacobson et al., J; Org. Chem, 44, 921-924, (1979)) or of starch and maltodextrins in oligomers having acid functions (M. Floor, Starch/Staërke, 41, 303-309, (1989)) or even as an epoxydizing agent of alkenes or an oxidation agent of primary and secondary alcohols in aldehydes and ketones (K. Sato, Bull. Chem. Soc. Jpn, 70, 905-915, (1997)).
The comparative performances of numerous salts, including sodium tungstate, as catalysts of the oxidation of carbohydrates, including glucono-delta-lactone (“GDL”). by hydrogen peroxide has been widely described by M. R. EVERETT and F. SHEPPARD in “Oxidation of Carbohydrates, Salt Catalysis”, University of Oklahoma Medical School, 1944, pp. 25-90. However, the quantities of salts envisaged are very high, that is generally several “ion equivalents”, i.e. several moles of the ion studied (anion or cation) per mole of carbohydrate.
Taking into account its poor efficiency, particularly with respect to bicarbonate anion which is presented as twice as efficient according to the second paragraph of page 44 of said document, the tungstate anion is used (in the form of sodium tungstate) at the rate of 4 equivalents with a view to catalyzing the oxidation, by hydrogen peroxide, of GDL provided in extremely diluted form (1% solution). The results presented in the tables VII page 42 and IX page 51 of said document do not, however, make it possible to know the exact nature and concentration of the product(s) resulting from the oxidation thus carried out in the presence of tungsten. In any case, the general teachings of this document go against the use of less than 4 equivalents of tungsten ions, taking into account the molecular mass of this metal (approximately 184) of less than 4×184, or approximately 736 g of tungsten, per mole of carbohydrate to be oxidized. Moreover, this document does not specifically envisage the use of molybdenum salts with a view to catalyzing the oxidation of carbohydrates by hydrogen peroxide.
Moreover, patent FR 2 346 451 envisages, in all generality and without giving examples, the possibility of using, amongst other catalysts, molybdenum oxides within the framework of the oxidation of gluconic acid into arabin saccharide. However, it is not unambiguously evident from the passage to be found on page 3, lines 17-26 of said patent, with which oxidant(s) the authors think it possible to associate the said molybdenum salts, and in particular whether it is a question of hydrogen peroxide, the use of which is exemplified in example 2 and/or of an acid such as peracetic acid (cf. example 8) or perbenzoic acid (cf. example 9). Whatever the case, the authors advocate quite particularly the combined use of hydrogen peroxide and of Fe
3 +
ions and thus a standard RUFF method.
Thus none of the documents quoted above describes nor really suggests the interest of using a specific system of tungsten salt/hydrogen peroxide or molybdenum salt/hydrogen peroxide for the reaction of oxidative decarboxylation of an acid derivative of saccharide, or one of its salts, in an aqueous phase. In particular, nothing suggests that it is possible to increase the selectivity of said reaction considerably, which translates into the noteworthy reduction in the production of co-products such as formic acid.
This new catalyst thus has a significant potential and, to the knowledge of the Applicant Company, no equivalent reaction exists.
DETAILED DESCRIPTION OF THE INVENTION
In a surprising and unexpected manner, the A
Henderson & Sturm LLP
Padmanabhan Sreeni
Roquette Freres
Zucker Paul A.
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