EP1007508A1

EP1007508A1 - Method for producing fatty acid polyglycol ester sulphates

Info

Publication number: EP1007508A1
Application number: EP98947432A
Authority: EP
Inventors: Hans-Christian Raths; Thomas Engels; Rainer Rüben; Jörg KAHRE
Original assignee: Cognis Deutschland GmbH and Co KG
Current assignee: BASF Personal Care and Nutrition GmbH
Priority date: 1997-08-25
Filing date: 1998-08-17
Publication date: 2000-06-14
Also published as: DE19736906A1; JP2001514166A; US6235913B1; AU9435498A; WO1999010319A1

Abstract

The invention relates to a method for producing fatty acid polyglycol ester sulphates of formula (I) R<1>COO(AO)nSO3M, wherein R<1>CO represents a linear or branched, aliphatic, saturated and/or unsaturated acyl radical with 6 to 22 carbon atoms, AO represents CH2CH2O, CHCH3CH2O and/or CH2CHCH3O, n represents numbers from 0.5 to 5 and M represents a cation, by sulfation of fatty acid polyglycol esters followed by neutralisation. The inventive method is characterised in that the entire neutralisation process is carried out at a pH of 5 to 9.

Description

Process for the preparation of fatty acid polyglycol ester sulfates

Field of the Invention

The application relates to a process for the preparation of fatty acid polyglycol ester sulfates by sulfating fatty acid polyglycol esters and subsequent neutralization, and the use thereof of foam boosters especially for nonionic surfactant mixtures.

State of the art

Fatty acid polyethylene glycol esters, in particular low ethoxylated fatty acids such as fatty acid + 1 E0 adducts, have been described in the literature for some time as an interesting precursor for the synthesis of ether sulfate surfactants with an isethionate-like structure. Initially, however, it was already difficult to produce the fatty acid polyethylene glycol esters to be used as starting compounds in satisfactory selectivities. In addition to the undesirable proportion of higher ethoxylated homologues, significant amounts of polyethylene glycol and diesters were also formed by the older processes known to date. Only recently, by using special alkanolamines as catalysts for the ethoxylation, has it been possible to produce low-ethoxylated fatty acids in yields of over 90% of theory. Apart from the fact that it was already difficult enough to provide the starting compounds in appropriate qualities, the sulfation of these compounds also presented considerable difficulties. According to the article by K. Engel and W. Ruback in Fette, Seifen, Anstrichm., 88, 20 (1986), sulfated fatty acid polyethylene glycol esters can be obtained by reacting fatty acid polyglycol esters with chlorosulfonic acid in methylene chloride, but after neutralization under normal conditions only Traces of anionic surfactants can be detected. In other words, after the neutralization there was a mixture which hardly contained any more anion-active sulfated fatty acid polyethylene glycol esters, but mainly hydrolysis products such as fatty acids, soaps, short-chain glycol mono- and glycol disulfates. Better results were obtained when the neutralization was carried out at temperatures between 0 and -20 ° C. However, such a method would be unsuitable for large-scale production since, on the one hand, methylene chloride was used as the solvent, which was carried out in a separate work-up step. would have to be separated, and on the other hand cooling for working temperatures below 0 ° C could be realized on an industrial scale with enormous effort.

Accordingly, the object of the present invention was to provide an improved process for the sulfation of especially low alkoxylated fatty acids, which can be used on an industrial scale to supply fatty acid polyglycol ester sulfates without further work-up.

Description of the invention

The present invention relates to a process for the preparation of fatty acid polyglycol ester sulfates of the formula (I),

R ¹ COO (AO) _n S0 ₃ M (I)

in which R ¹ CO is a linear or branched, aliphatic, saturated and / or unsaturated acyl radical having 6 to 22 carbon atoms, AO is CH2CH2O, CHCH3CH2O and / or CH2CHCH3O, n is a number from 0.5 to 5 and M is a cation , by sulfation of fatty acid polyglycol esters and subsequent neutralization, which is characterized in that the entire neutralization process is carried out at a pH of 5 to 9.

Surprisingly, it was found that when the neutralization is carried out under the specified conditions, fatty acid polyglycol ester sulfates are obtained in high yields and the problem of hydrolysis is reliably avoided.

Fatty acid polypropylene ester

The preparation of the sulfation products is based on fatty acid polyglycol esters which follow the formula (II)

R ¹ COO (AO) _n H (II)

in which R ¹ CO is a linear or branched, aliphatic, saturated and / or unsaturated acyl radical having 6 to 22 carbon atoms, AO is CH2CH2O, CHCH3CH2O and / or CH2CHCH3O and n is a number from 0.5 to 5. The esters can be prepared by known methods of preparative organic chemistry, for example by basic homogeneously catalyzed addition of ethylene oxide and / or propylene oxide to fatty acids. Fatty acids are to be understood as aliphatic carboxylic acids of the formula R ¹ COOH, in which R ¹ CO is an aliphatic, linear or branched acyl radical having 6 to 22, preferably 12 to 18 carbon atoms and 0 and / or 1, 2 or 3 double bonds. Typical examples are, ristinsäure caproic acid caprylic acid 2-ethylhexanoic acid, capric acid, lauric acid, isotridecanoic acid, myristyl, palmitic acid, palmitoleic acid, stearic acid, isostearic acid, oleic acid, elaidic acid, petrochemical Selin acid, linoleic acid, linolenic acid, elaeostearic acid, arachidic acid, Gadoieinsäure, behenic acid and erucic acid and their technical mixtures, which are obtained, for example, in the pressure splitting of natural fats and oils, in the reduction of aldehydes from Roelen's oxosynthesis or as a monomer fraction in the dimerization of unsaturated fatty acids. Technical fatty acids with 12 to 18 carbon atoms, such as coconut, palm, palm kernel or tallow fatty acids, are preferred. Accordingly, R ¹ CO in formula (I) or (II) is preferably an acyl radical having 12 to 18 carbon atoms.

Alkoxylation

Suitable basic catalysts for the alkoxylation are both alkanolamines such as monoethanolamine, diethanolamine and preferably triethanolamine and also the amines described in DE 2024050 AS such as mono-, di- and trimethylamine, mono-, di-, triethylamine, mono-, di - and tri-n-butylamine, tert. Butylamine, mono-, di- and tripropylamine, di-isopropylamine, n-hexylamine, n-dodecylamine, N, N-dimethyl-n-dodecylamine, N, N-dimethyloctadecylamine, docosylamine, hexamethylene diamine, N, N, N ' , N'-tetramethylhexamethylene diamine, tetraethylene pentamine, triethylene diamine, cyclohexylamine, aniline, benzylamine, hexamethylene tetramine, diethylene triamine, N, N-dimethylaniline, methoxyaniline and morpholine. The alkanolamines described are particularly preferred as catalysts. The alkanolamines are usually used in amounts of 0.1 to 5, preferably 0.5 to 1.5,% by weight, based on the fatty acids. The alkoxylation can be carried out in a manner known per se. Usually, the fatty acid and the catalyst are placed in a stirred autoclave, which is freed of traces of water by alternately evacuating and flushing with nitrogen before the reaction. The fatty acid is then reacted with ethylene oxide and / or propylene oxide in a molar ratio of 1: 0.5 to 1: 5, preferably 1: 1 to 1: 2, which, after heating, can be metered in portions into the pressure vessel using a siphon. Accordingly, in formula (I) or (II) n stands for a number from 0.5 to 5, preferably for a number from 1 to 2. The alkoxylation can be carried out at temperatures in the range from 80 to 180, preferably 100 to 120 ° C. and autogenous pressures in the range from 1 to 5, preferably 2 to 3, bar. After the end of the reaction, it is advisable to stir at the reaction temperature for a certain time to complete the conversion (15 to 90 min). The autoclave is then cooled, decompressed and, if desired, acids such as lactic acid or phosphoric acid are added to the product in order to neutralize the basic catalyst. For the purposes of the invention, either exclusively or exclusively propoxylated or also ethoxylated and propoxylated fatty acids are used as starting compounds. If ethoxylated and propoxylated fatty acids are used, they can be random or block compounds. In the case of the mixed alkoxylated fatty acids, the ratio of ethylene oxide and propylene oxide to be used can be set within a wide range, as long as the degree of alkoxylation n is in the above range. However, the consistency of the alkoxylated fatty acid can be influenced via the proportion of propylene oxide. As the degree of propylation increases, the softening temperature of the alkoxylated fatty acids becomes lower. If the fatty acids are exclusively propoxylated, even liquid products are obtained, while the exclusively ethoxylated fatty acids are solid compounds.

Sulfation

According to one embodiment, the sulfation of the fatty acid alkylene glycol esters can be carried out using gaseous sulfur trioxide in the manner known for fatty acid lower alkyl esters, preference being given to continuously operating reactors which operate on the falling film principle. The sulfur trioxide is diluted with an inert gas, preferably air or nitrogen, and used in the form of a gas mixture which contains the sulfur trioxide in a concentration of 1 to 8, in particular 2 to 5,% by volume. The molar ratio of fatty acid alkylene glycol ester to sulfur trioxide is generally 1: 1 to 1: 1.3, preferably 1: 1.05 to 1: 1.1. The sulfation is preferably carried out in a continuous falling film reactor at temperatures which are at least 5 to 10 ° C. above the melting point of the fatty acid alkylene glycol esters. As a rule, the sulfation temperatures are up to a maximum of 30 ° C above the melting point of the fatty acid alkylene glycol esters. According to a further embodiment of the present invention, the sulfation is carried out with a sulfation reagent, in particular with chlorosulfonic acid. The reaction takes place under conditions known to the person skilled in the art, for example in a continuously operating process with approximately stoichiometric amounts of chlorosulfonic acid.

Neutralization

It is essential to the invention that the acid esters of the formula (I) obtained after the sulfation are neutralized with bases in such a way that the pH is in the range from 5 and 9, preferably from 6 and 8, during the entire neutralization process. It has proven advantageous to carry out the neutralization in such a way that the acid ester is run into an aqueous solution, the pH of the aqueous solution always being adjusted to pH values between 5 and 9 by metering in the alkaline solution intended for neutralization is held. On an industrial scale, this can be done by simultaneously dosing the liquid acid ester and of the alkaline solution intended for neutralization into the neutralization cycle. An example of such a suitable neutralization circuit can be found in German published patent application DE 4017463 A1. Furthermore, it has proven to be advantageous to carry out the neutralization at temperatures from 10 ° C. to 40 ° C., preferably at 20 ° C. to 35 ° C. However, it is also possible to use any other neutralization method known to the person skilled in the art, such as, for example, spray neutralization, as long as the above pH value for neutralization is maintained. For the neutralization, hydroxides such as alkali metal, alkaline earth metal hydroxide or also ammonia can be used and / or also water-soluble organic amines such as mono-, di- and tri-C2-alkanolamines, for example mono-, di- and triethanolamine as well as primary, secondary or tertiary Cι-4-alkylamines. The neutralization bases are preferably used in the form of 20 to 50% by weight aqueous solutions. Aqueous solutions of ammonia or sodium and / or potassium hydroxide are particularly preferably used for the neutralization, so that in formula (I) M preferably represents a sodium, potassium or ammonium ion. M stands in particular for an ammonium ion, since such compounds of the formula (I) have particularly good solubility behavior. After neutralization, the aqueous solutions of the sulfation products are preferably adjusted to pH values between 6 and 7. Such solutions are stable even when stored for months at room temperature. If desired, the fatty acid polyglycol ester sulfates can subsequently be bleached in the manner known to the person skilled in the art, the bleaching also being carried out here at the above-mentioned pH values. Antimicrobial agents or pH buffers can also be added in amounts of up to 10% by weight, based on the active substance content of the sulfation products, to stabilize the storage of the aqueous preparations.

Sulfation products

Typically, the sulfation products - based on the non-aqueous fraction - have the following composition:

(a) 40 to 98% by weight of fatty acid alkylene glycol ester sulfates of the formula (I),

(b) 0.1 to 10% by weight of glycol mono- and glycol disulfates,

(c) 0.1 to 10% by weight of fatty acid soaps,

(d) 0.1 to 45% by weight unsulfated, i.e. Fatty acid polyglycol esters as well

(e) 0.1 to 15 wt .-% inorganic sulfates - based on solids mixture.

The aqueous fraction is not critical and can typically be in the range from 50 to 95% by weight. Industrial applicability

Within the scope of the invention, it was further found that the fatty acid polyglycol ester sulfates of the formula (I), alone or as a mixture with one or more of the compounds described under (b) to (e), are excellent foam boosters for low-foaming surfactant mixtures; Mixtures of the fatty acid polyglycol ester sulfates with unsulfated starting materials are also particularly suitable. These preparations can be prepared by mixing or also generated in situ, for example by only partially carrying out the sulfation. The low-foaming surfactant mixtures preferably contain nonionic surfactants. In the context of the present application, "weak foaming" refers to those surfactant mixtures which, according to the rotor test described in Example 2, have a foam volume of less than 500 ml after 3 minutes.

Nonionic surfactants

Nonionic surfactants that can be contained in the surfactant mixtures are fatty alcohol polyglycol ethers, alkyl phenol polyglycol ethers, fatty acid amide polyglycol ethers, fatty amine polyglycol ethers, alkoxylated triglycerides, mixed ethers, polyol fatty acid esters, fatty acid polyethyleneglycol esters, fatty acid methyl ester ethoxylates, acyl ester glucosorbides, sugar esters, glyceryl sorbides, sugar esters, glucosorbides, sorbyl glucosorbides, sugar esters, glucosorbides, sorbyl glucosorbides, sugar esters, sorbyl glycides, sorbylsorbyl glycides, sorbylsorbylsorbides, sugar esters, sorbylsorbides, sorbylsorbylsorbides, sorbylsorbylsorbides, sorbylsorbylsorbides, sorbylsorbylsorbides, sorbylsorbylsorbides, sorbylsorbylsorbides, sorbylsorbylsorbides, Especially with alkyl polyglycoside-containing surfactant mixtures, the problem may arise that these mixtures develop foam only slowly or have insufficient foam stabilities. This is particularly troublesome for personal care products, since the user of surfactant mixtures quickly wants beautiful, stable foams. It has now been shown that surfactant mixtures containing alkyl polyglycosides no longer have these disadvantages if sulfated fatty acid alkylene glycol esters are added alone or in a mixture with one or more of the compounds described under (b) to (e). Another object of the present invention therefore relates to the use of sulfated fatty acid polyalkylene glycol esters of the formula (I) as foam boosters for low-foaming surfactant mixtures. The compounds described are preferably used as foam boosters for surfactant mixtures containing nonionic surfactants, in particular for surfactant mixtures containing alkyl polyglycosides. The amount of fatty acid polyglycol ester sulfates added can be in the range from 0.1 to 5% by weight, based on the amount of solids in the preparations.

Alkyl polyglycosides

In the present application, the term alkyl polyglycosides is understood to mean alkyl and alkenyl oligoglycosides which follow the formula (III) R0- [G] _p fill)

in which R stands for an alkyl and / or alkenyl residue with 4 to 22 carbon atoms, G stands for a sugar residue with 5 or 6 carbon atoms and p stands for numbers from 1 to 10. They can be obtained according to the relevant procedures in preparative organic chemistry. The alkyl and / or aikenyl oligoglycosides can be derived from aldoses or ketoses with 5 or 6 carbon atoms, preferably glucose. The preferred alkyl and / or aikenyl oligoglycosides are thus alkyl and / or alkenyl oligoglucosides. The index number p in the general formula (III) indicates the degree of oligomerization (DP), ie the distribution of mono- and oligoglycosides, and stands for a number between 1 and 10. While p in a given compound must always be an integer, especially here can assume the values p = 1 to 6, the value p for a certain alkyl oligoglycoside is an analytically determined arithmetic parameter, which usually represents a fractional number. Alkyl and / or aikenyl oligoglycosides with an average degree of oligomerization p of 1.1 to 3.0 are preferably used. From an application point of view, preference is given to alkyl and / or aikenyl oligoglycosides whose degree of oligomerization is less than 1.7 and 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, capronic alcohol, caprylic alcohol, capric alcohol and undecyl alcohol and their technical mixtures, such as are obtained, for example, in the hydrogenation of technical fatty acid methyl esters or in the course of the hydrogenation of aldehydes from Roelen's oxosynthesis. Alkyl oligoglucosides of chain length C ₈ -Cιo (DP = 1 to 3) are preferred, which are obtained as a preliminary step in the separation of technical Cβ-Ciβ-coconut fatty alcohol by distillation and which can be contaminated with a proportion of less than 6% by weight of Ci2-alcohol as well as alkyl oligoglucosides 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 and their technical mixtures, which can be obtained as described above. Alkyl oligoglucosides based on hydrogenated C, 2/14 coconut alcohol with a DP of 1 to 3 are preferred.

Anionic, cationic and / or amphoteric surfactants

The surfactant mixtures can of course contain further surfactants, for example anionic, cationic and / or amphoteric surfactants. Typical examples of anionic surfactants are alkylbenzene sulfonates, alkane sulfonates, olefin sulfonates, alkyl ether sulfonates, glycerol ether sulfonates, α-methyl ester sulfonates, sulfo fatty acids, alkyl sulfates, fatty alcohol ether sulfates, glycerol ether sulfates, hydroxy mixed ether sulfates, fatty (ether) sulfate ethers, monoglyl ether sulfates, monoglyl ether sulfate and dialkyl sulfo succinates, mono- and dialkylsulfosuccinamates, sulfotriglycerides, amide soaps, ether carboxylic acids and their salts, fatty acid isethionates, fatty acid sarcosinates, fatty acid taurides, acyl lactylates, acyl tartrates, acyl glutamates, acyl aspartates, alkyl oligoglucosate acid phosphate products (ether-based protein phosphates), (protein oleaginate based phosphate products), (protein oleaginate base phosphate), (protein oleaginate base phosphate products), (protein oleaginate base phosphate), (protein oleaginate base phosphate) products (in particular, based on protein products), If the anionic surfactants contain polyglycol ether chains, they can have a conventional, but preferably a narrow, homolog distribution. Typical examples of cationic surfactants are quaternary ammonium compounds and ester quats, in particular quaternized fatty acid triaikanolamine ester salts. Typical examples of amphoteric or zwitterionic surfactants are alkyl betaines, alkyl amido betaines, aminopropionates, aminoglycinates, imidazolinium betaines and sulfobetaines.

Examples

Example 1. 200 g (1 mol) of technical lauric acid were placed in a 1 liter stirred autoclave and 2 g of triethanolamine (corresponding to 1% by weight, based on lauric acid) were added. The autoclave was alternately evacuated and pressurized with nitrogen three times to remove traces of water that could lead to the formation of polyethylene glycol. After the reaction mixture had been charged with nitrogen for the last time, the autoclave was closed and heated to 100 ° C. and 44 g (1 mol) of ethylene oxide were added in portions at a maximum pressure of 5 bar. After completion of the reaction, recognizable by the fact that the pressure dropped again to a value of 1.2 bar and then remained constant, stirring was continued for 30 minutes and the reaction mixture was then cooled and let down. The basic catalyst was neutralized by adding an appropriate amount of lactic acid. The lauric acid + 1 EO adduct obtained was melted at 40 ° C. and sulfated in a falling film reactor with gaseous sulfur trioxide (dilution 3 to 5% in dried air) in a molar ratio of 1: 1.1 at 40 ° C. The acidic ester obtained was neutralized with an aqueous ammonia solution which contained 1% by weight of triethanolamine, based on ammonia, at a temperature below 40 ° C. by allowing both solutions to run in together. The pH was always kept at 6 to 8. The solution was then adjusted to a pH of 6.5. The dried salt had the following composition:

Fatty acid polyglycol ester sulfate (anionic substance) 56.0% by weight

Glycol mono- and disulfate 7.5% by weight

Lauric acid ammonium salt 5.0% by weight

Ethylene glycol mono- and diesters (unsulfated components) 22.0% by weight

Ammonium sulfate 9.5% by weight

Example 2. 1 liter test solutions were prepared in 15 ° dH water (see Table 1). 200 ml of the test solutions were foamed at 40 ° C for 3 minutes in a rotor test (1300 rpm). With the help of a special stirring head, air is stirred into the test solution to be tested, which causes foaming. To measure the foaming kinetics, ie the foam behavior in the beginning, the stirrer is switched off at intervals of 10 seconds during the first 90 seconds in order to read the foam height and liquid level on the scale. The agitator is then switched on again. To determine the foam stability, the foam and liquid height is recorded for a further 5 minutes after the total stirring time of 3 minutes. The foaming kinetics are calculated from the linear part of the gradient line of the average foam volume determined within the first minute at intervals of 10 seconds. It is given in ml / s. The results are summarized in Table 1. Table 1

Foaming behavior (quantities in g)

It can be seen that the fatty acid polyglycol ester sulfates for alkyl polyglycosides (Coco Glucosides) produce better foaming kinetics than ether sulfates (sodium laureth sulfates) and also ensure better foaming behavior in the long term.

Claims

claims

1. Process for the preparation of fatty acid polyglycol ester sulfates of the formula (I),

RiCOO (AO) nS0 ₃ M (I)

in which R ¹ CO is a linear or branched, aliphatic, saturated and / or unsaturated acyl radical having 6 to 22 carbon atoms, AO is CH2CH2O, CHCH3CH2O and / or CH2CHCH3O, n is a number from 0.5 to 5 and M is a cation , by sulfation of fatty acid polyglycol esters and subsequent neutralization, characterized in that the entire neutralization process is carried out at a pH of 5 to 9.

2. The method according to claim 1, characterized in that fatty acid polyglycol esters of the formula (II) are used,

R COO (AO) _n H (II)

in which R ¹ CO is a linear or branched, aliphatic, saturated and / or unsaturated acyl radical having 6 to 22 carbon atoms, AO is CH2CH2O, CHCH3CH2O and / or CH2CHCH3O and n is a number from 0.5 to 5.

3. Process according to claims 1 or 2, characterized in that fatty acid polyglycol esters of the formula (II) are used in which R ¹ CO represents an alkyl radical having 12 to 18 carbon atoms.

4. Process according to claims 1 to 3, characterized in that fatty acid polyglycol esters of the formula (II) are used, in which n represents numbers from 1 to 2.

5. Process according to claims 1 to 4, characterized in that the fatty acid polyglycol esters are sulfated with sulfur trioxide in a molar ratio of 1: 1 to 1: 1.

6. Process according to claims 1 to 5, characterized in that the sulfation is carried out in a continuous working falling film reactor.

7. Process according to claims 1 to 6, characterized in that the sulfation is carried out at temperatures which are at least 5 to 10 ° C above the melting point of the fatty acid polyglycol esters.

8. The method according to claims 1 to 7, characterized in that one carries out the neutralization at temperatures of 10 ° C to 40 ° C.

9. Use of fatty acid polyglycol ester sulfates of the formula (I) as foam boosters for low-foaming surfactant mixtures.

10. Use according to claim 9, characterized in that the low-foaming surfactant mixtures contain nonionic surfactants.