WO2004052901A1

WO2004052901A1 - Methods for producing alkyl polyglucosides or alkenyl polyglucosides containing carboxyl groups

Info

Publication number: WO2004052901A1
Application number: PCT/EP2003/013562
Authority: WO
Inventors: Ansgar Behler; Karl Heinz Schmid; Almud Folge
Original assignee: Cognis Ip Management Gmbh
Priority date: 2002-12-10
Filing date: 2003-12-02
Publication date: 2004-06-24
Also published as: DE10257523A1

Abstract

The invention relates to methods for producing alkyl polyglucosides containing acid groups, whereby a reaction mixture containing at least one alkyl polyglucoside is reacted with a compound containing at least two COOH groups, in the presence of an organic sulfonic acid, or a mixture of at least two of the same.

Description

Process for the preparation of carboxyl-containing alkyl or alkenyl polyglycosides

The present invention relates to processes for the preparation of alkyl polyglycosides containing acid groups, in which a reaction mixture comprising at least one alkyl polyglycoside is reacted with a compound having at least two COOH groups in the presence of an organic sulfonic acid, or a mixture of two or more thereof.

Alkyl oligoglucosides are important surfactants because they are compatible as non-ionic compounds with a variety of other ingredients, but have a foaming and cleaning ability that is much more like that of anionic surfactants. Because of their mild surfactant properties, alkyl polyglycosides are also popular components of active washing and cleaning compositions and cosmetics.

However, the known nonionic surfactants have the disadvantage that they often have only a limited solubility in water and a comparatively low foaming capacity, in particular in applications with high demands on the foaming power. Despite their otherwise excellent properties, the range of use of such nonionic surfactants is therefore limited.

The esterification of alcohols with polyvalent carboxylic acids is a tried and tested method that has been known for a long time and is also used industrially to produce anionic surfactants. The neutralized carboxylic acid salts of alcohols or ethoxylated alcohols are often excellent surface-active compounds and are often used in detergents and cleaning agents, mild detergents and cleaning agents, shampoos and other mild cleaning agents and in cosmetics.

Various attempts have therefore been made in the past to convert the mild nonionic surfactants mentioned into anionic surfactants carrying carboxyl groups by known esterification reactions of alkyl polyglycosides with polyvalent carboxylic acids. It turned out, however, that the reaction conditions, such as those prevailing in esterification reactions known to date, led to an associated poor product quality or that the desired product does not form at all or only to a small extent.

There is, however, a fundamental need for anionic surfactants which carry carboxyl groups and which have the mild surfactant properties of the above-mentioned nonionic surfactants, but which have better water solubility, better sensory properties and improved foaming power.

EP 0 258 814 B1 describes, for example, surfactants which can be obtained by esterifying polyhydroxy compounds with two or three carboxyl-containing hydroxycarboxylic acids. For example, the reaction of C ₆ -i ₆ alkyl polyglycosides with tartaric acid or citric acid is described. However, the reactions described do not yet show a satisfactory yield and a dominant proportion of side reactions, especially with regard to the reaction with tartaric acid.

EP 0 510 564 B1 relates to a process for the preparation of esters of di- or tricarboxylic acids, in particular the esterification of alkyl polyglycosides. The reactions described are carried out without a catalyst and have unsatisfactory yields and a dominant proportion of side reactions.

The present invention was therefore based on the object of providing a process for the preparation of anionic surfactants based on alkyl or alkenyl polyglycosides which does not have the disadvantages of the processes known from the prior art.

The object on which the invention is based is achieved by a process for the preparation of alkyl or alkenyl polyglycosides carrying carboxyl groups, as is described in the context of the text below.

The present invention therefore relates to a process for the preparation of alkyl or alkenyl polyglycosides containing carboxyl groups, in which a reaction mixture comprising at least one alkyl or alkenyl polyglycoside of the general formula I RO (G) z (I), in which R represents an alkyl and / or alkenyl radical having 4 to 22 carbon atoms, G represents a sugar radical having 5 or 6 carbon atoms and z represents numbers from 1 to 10, or a mixture of two or more thereof, and at least one compound having two COOH groups is reacted in the presence of an organic sulfonic acid or a mixture of two or more thereof.

Alkyl or alkenyl polyglycosides are known nonionic surfactants which follow the formula (I)

RO (G) z (I), in which R represents an alkyl and / or alkenyl radical having 4 to 22 carbon atoms, G represents a sugar radical having 5 or 6 carbon atoms and z represents numbers from 1 to 10. They can be obtained according to the relevant procedures in preparative organic chemistry. As a representative of the extensive literature, reference is made here to the publications EP A1 0301298, WO 90/03977 and to "Alkyl Polyglycosides, Technology, Properties and Applications" (K. Hill, VCH 1997).

The alkyl and / or alkenyl oligoglycosides can be derived from aldoses or ketoses with 5 or 6 carbon atoms, preferably glucose. The preferred alkyl and / or alkenyl oligoglycosides are thus alkyl and / or alkenyl oligoglucosides. The index number z in the general formula (I) indicates the degree of oligomerization (DP), ie. H. the distribution of mono- and oligoglycosides is present and stands for a number between 1 and 10. While z must always be an integer in a given compound and here can take on the values z = 1 to 6, the value z is for a certain alkyl oligoglycoside an analytically calculated quantity, which is usually represented by a fractional number.

In the context of the present invention, preference is given to using alkyl and / or alkenyl oligoglycosides with an average degree of oligomerization z of 1.1 to 3.0. From an application point of view, preference is given to those alkyl and / or alkenyl oligoglycosides whose degree of oligomerization z is less than 1.7 and is in particular between 1.2 and 1.4.

The alkyl or alkenyl radical R can be derived from primary alcohols having 4 to 11, preferably 8 to 10, carbon atoms. Typical examples are butanol, Hexanol, octanol, capric alcohol and undecyl alcohol and the tech _¬ American mixtures as säuremethylestern example, in the hydrogenation of technical fatty _¬ or obtained in the hydrogenation of aldehydes from Roelen's oxo synthesis. Alkyl oligoglycosides of chain length C ₈ -Cιo (DP = 1 to 3) are preferred, which are obtained as a preliminary step in the separation of technical C ₈ -C ₁₈ coconut fatty alcohol by distillation and with a proportion of less than 6% by weight of Cι ₂ alcohol can be contaminated and alkyl oligoglycosides based on technical Cg / n-oxo alcohols (DP = 1 to 3). The alkyl or alkenyl radical R can also be derived from primary alcohols having 12 to 22, preferably 12 to 14, carbon atoms. Typical examples are lauryl alcohol, myristyl alcohol, cetyl alcohol, palmoleyl alcohol, stearyl alcohol, isostearyl alcohol, oleyl alcohol, elaidyl alcohol, petroselinyl alcohol, arachyl alcohol, gadoleyl alcohol, behenyl alcohol, erucyl alcohol, brassidyl alcohol, such as those described above, and their technical mixtures. Alkyl oligoglycosides are preferably based on hydrogenated Cι ₂ / i4 coconut alcohol with a DP of 1 to 3

The alkyl or alkenyl polyglycosides can in principle be used in any form, for example in the form present after their synthesis, as a product mixture. However, it is preferred according to the invention if the alkyl or alkenyl polyglycosides used have a free fatty alcohol content of about 30% by weight or less, in particular about 15% by weight or less, for example less than about 10 or less than about 5 % By weight.

The depletion of alkyl or alkenyl polyglycosides to an alcohol content suitable according to the invention is to be carried out from a technical point of view, taking into account the known low temperature resistance of sugar surfactants (risk of caramelization). For this, all types of evaporator, come in costume Be ^¬ that take this into account but preferably thin-film evaporator, falling film evaporators or short path and - if necessary - any combination of these components. The depletion can then take place in a manner known per se, for example at temperatures in the range from 110 to 220 ° C. and reduced pressures from 0.1 to 10 mbar. For the sake of simplicity, the term “alkyl polyglycosides” is used synonymously for both alkyl and alkenyl polyglycosides in the context of the present text, unless expressly stated otherwise.

In principle, all saturated or unsaturated, linear or branched or aromatic polycarboxylic acids are suitable as compounds having at least two COOH groups in the context of the present invention. A polycarboxylic acid suitable according to the invention preferably has two to about 6 COOH groups, in particular 2, 3 or 4 COOH groups. In addition to the COOH groups, a compound which can be used as a polycarboxylic acid according to the invention can also have one or more substituents, for example hydroxyl, mercapto or amino groups.

Suitable polycarboxylic acids in the context of the present invention are, in particular, citric acid, tartaric acid, malonic acid, succinic acid, fumaric acid, malic acid or maleic acid or mixtures of two or more thereof.

The molar ratio of alkyl polyglycoside or alkyl polyglycosides to polycarboxylic acid or polycarboxylic acids in the reaction mixture, as is implemented in the context of the present invention, is at most about 1: 1. However, the reaction according to the invention is preferably carried out such that the molar ratio of alkyl polyglycoside or alkyl polyglycosides to polycarboxylic acid or polycarboxylic acids is about 1: 1.8 to about 1: 1 or about 1: 1.5 to about 1: 1.05 or about 1 : 1, 4 to about 1: 1, 1 or about 1: 1, 3 to about 1: 1, 15 or about 1: 1, 25 to about 1: 1, 18. Particularly suitable mixtures have, for example, a ratio of alkyl polyglycoside or alkyl polyglycosides to polycarboxylic acid or polycarboxylic acids of about 1: 1, 45 to about 1: 1, 35 or about 1: 1, 05 to about 1: 1, 15.

In addition to an alkyl polyglycoside or a mixture of two or more alkyl polyglycosides and a polycarboxylic acid or a mixture of two or more polycarboxylic acids, a reaction mixture which is to be subjected to a reaction according to the invention also contains at least one organic sulfonic acid.

Typical examples of organic sulfonic acids suitable in the form of the preparations according to the invention are alkylbenzenesulfonic acids, secondary alkanesulfonic acids, olefin sulfonic acids, alkyl ether sulfonic acids, sulfofatty acids, alkyl and / or alkenyl sulfonic acids. If the anionic surfactants contain polyglycol ether chains, may have a conventional, but preferably a narrow homolog distribution.

Sulfonic acids are preferably selected from the group consisting of alkyl and / or alkenyl sulfonic acids, alkyl ether sulfonic acids, alkyl benzene sulfonic acids and alkane sulfonic acids, in particular fatty alcohol sulfonic acids, fatty alcohol ether sulfonic acids, secondary alkane sulfonic acids and linear alkyl benzene sulfonic acids.

Alkylethersulfonsäuren

Alkyl ether sulfonic acids are produced on an industrial scale by SO ₃ or chlorosulfonic acid (CSA) sulfation of fatty alcohol or oxo alcohol polyglycol ethers. For the purposes of the invention, ether sulfonic acids are suitable which follow the formula (II)

R ¹ O- (CH ₂ CH ₂ θ) aSO ₃ H (II) in which R ^{1 represents} a linear or branched alkyl and / or alkenyl radical having 6 to 22 carbon atoms and a represents numbers from 1 to 10. Typical examples are the sulfonic acids of addition products with an average of 1 to 10 and in particular 2 to 5 moles of ethylene oxide with capron alcohol, caprylic alcohol, 2-ethylhexyl alcohol, capric alcohol, lauryl alcohol, isotridecyl alcohol, myristyl alcohol, cetyl alcohol, palmoleyl alcohol, stearyl alcohol, oleyl alcohol, isostyl alcohol, isostyl alcohol, isostyl alcohol, isostyl alcohol, Petroselinyl alcohol, arachyl alcohol, gadoleyl alcohol, behenyl alcohol, erucyl alcohol and brassidyl alcohol and their technical mixtures. The ether sulfonic acids can have both a conventional and a narrow homolog distribution.

alkylbenzenesulfonates

Alkylbenzenesulfonates preferably follow the formula (III),

R ² -Ph-SO ₃ H (III) in which R ^{2 is} a branched, but preferably linear alkyl radical having 10 to 18 carbon atoms and Ph is a phenyl radical. Dode- cylbenzenesulfonic acids, tetradecylbenzenesulfonic acids, hexadecylbenzenesulfonic acids and their technical mixtures.

The proportion of the organic sulfonic acid or of the mixture of two or more organic sulfonic acids in the reaction mixture is about 0.01 to about 3, in particular about 0.1 to about 1% by weight.

It has proven useful in the context of the present invention to carry out the reaction according to the invention in the presence of an inert, organic solvent or a mixture of two or more inert organic solvents. Aprotic solvents which have a boiling point of more than about 120 ° C., in particular more than about 140 ° C., are particularly suitable. End group-capped ether compounds such as ethylene glycol dimethyl ether or ethylene glycol diethyl ether are particularly preferred. Solvents such as cyclohexanone (bp .: 155 ° C.), N-methylpyrrolidone (bp .: 204 ° C.), sulfolane (bp .: 285 ° C.), nitrobenzene (bp .: 210 ° C.), xylene are also suitable (Bp: 140 ° C).

To carry out the process according to the invention, the individual constituents of the reaction mixture are transferred to a suitable reaction vessel either simultaneously or in any order in succession. The reaction mixture is then largely or completely freed of oxygen or at least separated from direct contact with atmospheric oxygen by suitable methods, for example by saturation with or at least by covering with an inert gas, in particular with nitrogen or a noble gas. The reaction mixture is then preferably heated to the reaction temperature with stirring. A suitable reaction temperature for the process according to the invention is, for example, in a range from approximately 80 to approximately 180 ° C., but preferably approximately 120 to 160, in particular approximately 130 to approximately 150 ° C. The reaction can be carried out under ambient pressure. However, it is preferably carried out at reduced pressure, in particular at about 200 to about 900, for example about 500 to about 800 mbar.

The water of reaction formed during the reaction is removed from the reaction mixture by suitable separation methods during the reaction. Appropriate methods are known to the person skilled in the art. The reaction mixture is left at the reaction temperature for at least a period of time sufficient to convert at least 80% of the polycarboxylic acids contained in the reaction mixture. The reaction time is preferably about 1 to about 20 hours, in particular about 2 to about 10 or about 4 to about 8 hours.

After the reaction has ended, the reaction mixture is cooled to room temperature with or without external measures. However, it is also possible to treat the reaction mixture further at an essentially arbitrary temperature, for example to make it up or to fill it in containers.

It is also provided within the scope of the present invention to subject the mixtures obtainable by a process according to the invention to neutralization. To this end, an inorganic or organic base is added to a product mixture obtainable by a process according to the invention until a desired degree of neutralization is reached.

Examples of suitable inorganic bases are the hydroxides or the oxides of the alkali metals or the alkaline earth metals, in particular the hydroxides or the oxides of Li, Na or K. Particularly suitable organic bases are ammonia or optionally substituted amino compounds such as alkylamines, dialkylamines or trialkylamines or ethanolamine, Diethanolamine or triethanolamine and the like.

The neutralization can be carried out according to known processes, for example as a batch process or continuously.

The reaction products obtainable by the process according to the invention are distinguished in particular by a significantly improved foaming power compared to the untreated starting materials. In particular when the molar ratio of alkyl polyglycosides to polycarboxylic acids is 1: 1.05 to about 1: 1.3, the reaction products obtained have particularly good foaming power.

The present invention therefore also relates to a surfactant composition obtainable by a process according to the invention. The compounds obtained by the process according to the invention have excellent surfactant properties. They are largely biodegradable, essentially non-toxic, and cause less skin irritation than the anionic surfactants commonly used. The compounds show excellent wetting and foaming behavior, and they also have excellent water solubility.

The compounds produced by the process according to the invention are suitable, for example, for use in detergents and cleaning agents, in personal care compositions and in cosmetics.

In addition to the compounds prepared according to the invention, suitable detergents and cleaning agents can also contain other typical ingredients, such as further anionic surfactants, builders, bleaching agents, bleach activators, detergency boosters, enzymes, enzyme stabilizers, graying inhibitors, optical brighteners, soil repellants, foam inhibitors, inorganic salts and fragrances and colorants contain. Appropriate compositions are known to the person skilled in the art.

Suitable personal care products are, for example, shampoos, shower baths or foam baths.

The invention is explained in more detail below by examples.

Examples

Example 1: Preparation of ₂ Cι _/ ι ₄ alkyl polyglycoside tartrate (1: 1, 4)

420.8 g (1, 0 mol) of dried Cι ₂ / ι ₄ alkyl polyglycoside (Plantacare 1200 G), 210 g (1, 4 mol) of tartaric acid, 0.6 g (0.1 wt .-%) Dodecanbenzol-sulfonic acid and 84.2 g of diethylene glycol diethyl ether were reacted in a distillation apparatus, first under nitrogen and then under vacuum (750 mbar) at 140 ° C. 27.8 g of distillate passed over. The total reaction time was 6 hours. There was a dark colored, solid product.

The acid number was 129 (theory: 109.7) and the free tartaric acid content was 10.4% by weight.

Example 2: Preparation of C _{2 /} i ₄ -alkyl polyglycoside tartrate (1: 1, 1)

420.8 g (1, 0 mol) of dried Cι ι ₂ ₄ alkylpolyglycoside (Plantacare 1200 G), 165.1 g (1, 1 mol) of tartaric acid, 0.6 g (0.1 wt .-%) Dodecanbenzol- Sulfonic acid and 84.6 g of diethylene glycol diethyl ether were reacted in a distillation apparatus, first under nitrogen and then under vacuum (750 mbar) at 140 ° C. 24.2 g of distillate passed over. The total reaction time was 4 hours. There was a dark colored, solid product.

The acid number was 97 (theory: 92) and the free tartaric acid content was 9.3% by weight.

Comparative Example:

277.0 g (0.658 mol) of dried C _2/14 alkyl polyglycoside (Plantacare 1200 G), 69.2 g (0.461 mol) of tartaric acid, 1.1 g of potassium hydrogen sulfate were in a distillation apparatus under vacuum (50 mbar) at 140 ° C. brought to reaction. 9.8 g of distillate passed over. The total reaction time was 2 hours. There was a dark colored, solid product. The acid number was 0.3 (theory: 113.1) and the free tartaric acid content was 3.8% by weight. Obviously, self-condensation of tartaric acid was the preferred reaction.

To investigate the foam behavior, aqueous surfactant mixtures were prepared and the foam volume was determined in accordance with DIN standard 53 902, part 1 (0.2 g active substance / l; 40 ° C; 15 ° dH; pH 6.0). In this method, the foam is generated by beating the liquid sample in a standing cylinder with a style-fixed, horizontally oriented, perforated plate for 30 seconds. The resulting foam volume is measured immediately after completing the shaving, as well as after 5 and 20 minutes.

The results for the compounds prepared according to the invention in comparison with a commercially available alkyl polyglycoside are shown in the table below.

Claims

claims

1. Process for the preparation of alkyl polyglycosides containing carboxyl groups, in which a reaction mixture containing at least one alkyl polyglycoside of the general formula I

RO (G) z (I), in which R represents an alkyl and / or alkenyl radical having 4 to 22 carbon atoms, G represents a sugar radical having 5 or 6 carbon atoms and z represents numbers from 1 to 10, with at least two COOH -Group compound in the presence of an organic sulfonic acid, or a mixture of two or more organic sulfonic acids, is reacted.

2. The method according to claim 1, characterized in that at least one aromatic sulfonic acid is used as the organic sulfonic acid.

3. The method according to claim 1 or 2, characterized in that the reaction mixture contains an inert organic solvent.

4. The method according to any one of claims 1 to 3, characterized in that the reaction mixture contains an inert organic solvent with a boiling point of more than 140 ° C.

5. The method according to any one of claims 1 to 4, characterized in that the reaction mixture as a compound having at least two COOH groups contains a compound selected from the group consisting of citric acid, malonic acid, maleic acid, fumaric acid or tartaric acid.

6. The method according to any one of claims 1 to 5, characterized in that the reaction mixture contains less than 15 wt .-% fatty alcohol.

7. The method according to any one of claims 1 to 6, characterized in that the reaction is carried out at a temperature of at least 120 ° C.

8. The method according to any one of claims 1 to 7, characterized in that the reaction is carried out at a temperature of at most 150 ° C.

9. The method according to any one of claims 1 to 8, characterized in that the reaction is carried out for a period of 1 to 10 hours.

10. The method according to any one of claims 1 to 9, characterized in that the molar ratio of alkyl polyglycosides to at least two compounds having COOH groups is 1: 1 or less.

11. surfactant composition obtainable by a process according to any one of claims 1 to 10.