Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Reexamination Certificate
2001-02-26
2001-11-20
Barts, Samuel (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
C568S469900, C568S496000, C568S497000, C568S385000, C568S861000, C568S862000, C564S397000
Reexamination Certificate
active
06320084
ABSTRACT:
FIELD OF THE INVENTION
The invention pertains to a process for the preparation of glyceraldehyde, or acetals or hemiacetals thereof, and to 3-aminopropane-1,2-diol derivatives.
BACKGROUND OF THE INVENTION
Processes for preparing glyceraldehyde and acetals or hemiacetals thereof are known. Commonly, glyceraldehyde is made from acrolein or its acetal. In U.S. Pat. No. 2,947,761 a process for preparing glyceraldehyde is disclosed. This process makes use of acrolein as starting material, which is subjected to an epoxidation with hydrogen peroxide followed by ring opening. However, this method suffers from a number of drawbacks. In particular, hydrogen peroxide is a strong oxidizing agent which can transform the carbonyl group of acrolein into a carboxylic acid group, which leads to considerable amounts of side products. A further disadvantage of this method is that great care must be taken to maintain a constant pH level during the epoxidation reaction.
The instant invention has for its object to provide a simple method without the above-mentioned drawbacks.
SUMMARY OF THE INVENTION
The present invention generally relates to a process for the preparation of glyceraldehyde or an acetal or hemiacetal thereof. The process is characterized in that 3-butene-1,2-diol is dissolved in a lower alkanol and subjected to ozonolysis to obtain a 3-hydroperoxy-3-alkoxy-propane-1,2-diol, which is subjected to a reductive treatment to obtain a hemiacetal of glyceraldehyde, which optionally may be converted into glyceraldehyde, or an acetal or a hemiacetal thereof.
DETAILED DESCRIPTION OF THE INVENTION
The invention relates to a process for the preparation of glyceraldehyde or an acetal or hemiacetal thereof wherein 3-butene-1,2-diol is dissolved in a lower alkanol and subjected to ozonolysis to obtain a 3-hydroperoxy-3-alkoxy-propane-1,2-diol, which is subjected to a reductive treatment to obtain a hemiacetal of glyceraldehyde, which optionally may be converted into glyceraldehyde, or an acetal or a hemiacetal thereof. This new method provides glyceraldehyde and derivatives thereof in high yields at low cost, and further has the advantage of avoiding expensive heating procedures during the reaction, using ambient reaction temperatures and low pressures when hydrogen is used as reducing means.
The ozonolysis reaction is performed in such a way that the temperature of the reaction mixture is kept between −25 and +50° C., preferably between −10 and +25° C., and most preferably between 0 and +15° C. In order to prevent the accumulation of hydroperoxides, the ozonolysis is most preferably performed in a continuous manner.
The lower alkanol in which the reaction is performed is an aliphatic or cyclo-aliphatic compound having 1-6 carbon atoms comprising at least one hydroxy group. Lower alkyl alcohols are preferred, in particular methanol and ethanol. Of these, methanol is the most preferred alcohol.
When such lower alkanol is used as the solvent, a hemiacetal of glyceraldehyde can be obtained directly through the lower alkoxyhydroperoxide derivative. The term “alkoxy” refers to the alkoxy group corresponding to the previously mentioned lower alkanol without the hydrogen atom of the hydroxy group. Therefore, it is preferred to make a lower alkoxy hemiacetal of glyceraldehyde, particularly 1-methoxy-propane-1,2,3-triol, but if so desired, the hemiacetal may be converted into the corresponding aldehyde or acetal by methods well known in the art. Acetals can, for example, be prepared by further treatment of the hemiacetal with an excess of an alcohol in an acidic medium. Hemiacetals can easily be hydrolyzed to aldehydes.
The invention further pertains to the synthesis of amine derivatives by converting the hemiacetal of glyceraldehyde into a 3-aminopropane-1,2-diol derivative, by subjecting the hemiacetal of glyceraldehyde to a reductive treatment in the presence of ammonia, or a primary or secondary amine. Preferably, the 3-aminopropane1,2-diol derivative is obtained by subjecting the hemiacetal of glyceraldehyde to a reductive treatment in the presence of an amine with the formula R
1
R
2
NH, wherein R
1
and R
2
independently are hydrogen or an alkyl group with 1-18 carbon atoms, or R
1
and R
2
together with the nitrogen atom to which they are bonded form a 5- or 6-membered ring, to give a compound with the formula R
1
R
2
N—CH
2
—CHOH—CH
2
OH, wherein R
1
and R
2
have the previously given meanings.
The reductive treatment can be performed in any manner that is known in the art for the reduction of the hydroperoxide intermediate. A convenient method comprises a treatment with hydrogen in the presence of a heterogeneous catalyst. Preferably, the reduction process is performed by continuously feeding the lower alkanol solution of 3-butene-1,3-diol to the reactor in which the reductive treatment is performed, with the hydroperoxide concentration in the reaction mixture being kept as low as possible to avoid side reactions and the accumulation of hydroperoxidic material. Most preferably, the reductive treatment is performed such that the rate of hydroperoxide dosing is low enough to allow the reduction reaction to be completed without an excess of hydroperoxide building up, thereby preventing hydroperoxide accumulation.
If a reductive amination is desired, the reaction can be performed under similar conditions to the reduction procedure, but in the presence of a primary or secondary aliphatic or cyclic amine of the formula R
1
R
2
NH, wherein R
1
and R
2
independently are hydrogen or an alkyl group with 1-18 carbon atoms, or R
1
and R
2
together with the nitrogen atom to which they are bonded form a 5- or 6-membered ring. The reductive amination can be performed in a separate reactor after the reductive treatment. Preferably, the reductive treatment and the reductive amination reactions are performed together in one process step in the same reactor in the presence of amine R
1
R
2
NH, using the previously mentioned reduction conditions. The term “alkyl group” also includes branched and unsaturated alkyl groups.
Examples of amines include ammonia, hydrocarbyl primary amines including alkylamine, such as methylamine, ethylamine, propylamine, isopropylamine, butylamine, isobutylamine, isomers of hexylamine, isomers of coco amine, and isomers of (hydrogenated) tallow amine; alkylene diamine, such as ethylene diamine, propylene diamine, isopropylene diamine, butylene diamine, isobutylene diamine, and isomers of hexamethylene diamine; dialkylene triamine, such as diethylene triamine, dipropylene triamine, diisopropyl triamine, isomers of dibutyl triamine, and isomers of dihexyl triamine, trialkylene tetramine, such as triethylene tetramine and isomers of tripropylene tetramine, tetraalkylene pentamine, such as tetraethylene pentamine, pentalkylene hexamine, such as pentaethylene hexamine; dialkyl aminoalkylamine, such as dimethyl aminomethylamine, dimethyl aminoethylamine, dimethyl aminomethylamine, dimethyl aminopropylamine, dimethyl aminobutylamine, dimethyl aminohexylamine, diethyl aminomethylamine, diethyl aminoethylamine, diethyl aminopropylamine, diethyl aminobutylamine, diethyl aminopentylamine, diethyl aminohexylamine, dipropyl aminomethylamine, dipropyl aminoethylamine, dipropyl aminopropylamine, dipropyl aminobutylamine, dipropyl aminopentylamine, dipropyl aminohexylamine, piperidine, azolidine, morpholine, and the like. Aromatic amines can also be used, such as o-, m-, or p-phenylene diamine, alkyl substituted o-, m-, or p-phenylene diamine, aniline, alkylene aniline, including products like methylene dianiline and dimethylene trianiline, polyalkylene aniline, and the like.
Preferably, the reductive alkylation is performed with 1-methoxy-propane-1,2,3-triol and hydrogen on dimethylamine to obtain 3-(dimethylamino)-1,2-propanediol.
The heterogeneous catalyst is selected from a transition metal on active carbon, such as nickel, iron, platinum, palladium, and the like. Palladium on active carbon is a preferred heterogeneous catalyst.
The hydrogenation catalyst may be an
Bergfeld Manfred Josef
Wecker Ulrich
Akzo Nobel nv
Barts Samuel
Mancini Ralph J.
Price Elvis O.
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