WO1996016924A1

WO1996016924A1 - Process for producing complex esters

Info

Publication number: WO1996016924A1
Application number: PCT/EP1995/004623
Authority: WO
Inventors: Andreas Sander; Rainer Von Kries
Original assignee: Henkel Kommanditgesellschaft Auf Aktien
Priority date: 1994-12-02
Filing date: 1995-11-23
Publication date: 1996-06-06
Also published as: DE4442988C1

Abstract

A process for producing complex esters is proposed in which: (a) oxy-fatty acids are subjected to self-condensation at a temperature of 200-280 °C; and (b) the resulting polyhydroxy fatty acids are esterified with polyols without being allowed to cool.

Description

Process for the preparation of complex esters

Field of the Invention

The invention relates to a process for the preparation of complex esters, in which hydroxy fatty acids are initially subjected to self-condensation at high temperatures and the resulting polyhydroxy fatty acids are then esterified with polyols without cooling.

State of the art

Complex esters of the polyglycerol polyricinoleates type have long been known as W / O emulsifiers and can be used for the formulation of low-viscosity / O emulsions [cf. EP-AI 0559013 (Th. Goldschmidt). EP-AI 0440203 (Lotte Co.) and WO 85/04346 (Meiji Milk Prods.)].

For their preparation, glycerol and ricinoleic acid are usually first polymerized separately and the polymers are then esterified with one another. Although this process is implemented on an industrial scale, it is associated with a high technical outlay in terms of separate boilers or boiler occupancy times. In principle, it is also possible to submit glycerol or polyglycerol and ricinoleic acid together and to let the self-condensation and the esterification run simultaneously or next to one another. However, it turns out that the esterification proceeds more quickly and the proportion of polymeric ricinoleic acids in the complex ester is low.

The object of the invention was therefore to provide an improved process for the preparation of polyol polyhydroxy fatty acid esters which is free from the disadvantages described.

Description of the invention

The invention relates to a process for the preparation of complex esters, in which

(a) subjecting hydroxy fatty acids to self-condensation at temperatures in the range from 200 to 280 ° C. and

(b) esterifying the resulting polyhydroxy fatty acids with polyols without cooling.

Surprisingly, it was found that complex esters with a high proportion of polymeric hydroxy fatty acids can be produced with minimal technical effort if the polyhydroxy fatty acids are first prepared and the esterification component is metered into the hot reaction mixture. A particular advantage when using polyglycerol as the polyol is furthermore that the polyglycerol generally has a residual alkaline catalyst content due to the production process which is very useful in the esterification with the polyhydroxy fatty acid.

Hydroxy fatty acids

Particularly suitable hydroxy fatty acids are ricinoleic acid and 12-hydroxystearic acid and mixtures thereof. The latter can be prepared by mixing the two components or partially curing the ricinoleic acid.

Polvole

The term polyols is understood to mean substances which have at least two, preferably 3 to 12 and in particular 3 to 8 hydroxyl groups and 2 to 12 carbon atoms. Typical examples are:

*** glycerin,

*** Alkylene glycols such as ethylene glycol, ethylene glycol, propylene glycol;

*** polyglycerin;

*** Methyl compounds, such as in particular trimethylolethane, trimethylolpropane, trimethylolbutane, pentaerythritol and dipentaerythritol;

*** Alkyl glucosides with 1 to 22, preferably 1 to 8 and in particular 1 to 4 carbons in the alkyl radical, such as methyl and butyl glucoside;

*** Sugar alcohols with 5 to 12 carbon atoms, such as sorbitol or mannitol, *** Sugar with 5 to 12 carbon atoms such as

Glucose or sucrose, *** aminosugars such as glucamine.

Individual polyols, but also mixtures, can be used.

Polyglycerin

In a preferred embodiment of the invention, technical polyglycerols are used as polyols, in particular those which have the following homolog distribution (the preferred ranges are given in brackets):

Glycerin 5 to 35 (15 to 30) wt%

Diglycerols 15 to 40 (20 to 32) wt%

Triglycerols 10 to 35 (15 to 25)% by weight

Tetraglycerols 5 to 20 (8 to 15) wt%

Pentaglycerols 2 to 10 (3 to 8) wt%

Oligoglycerols ad 100% by weight

The production of a polyglycerol of the abovementioned composition can be carried out by self-condensation of glycerol in the presence of suitable catalysts such as, for example, potassium carbonate, silicates according to DE-Al 4029323 (Henkel) or borates according to DE-Al 4117033 (Henkel) at temperatures in the range from 200 to 260 ° C are carried out. Other esterification components

It is possible to add further alcohols or carboxylic acids such as e.g. Condensate fatty alcohols, fatty acids, fatty alcohol polyglycol ethers and / or fruit acids.

Typical examples of fatty alcohols are capronic alcohol, capyl alcohol, 2-ethylhexyl alcohol, capric alcohol, lauryl alcohol, isotridecyl alcohol, myristyl alcohol, cetyl alcohol, palm oleyl alcohol, stearyl alcohol, isostearyl alcohol, oleyl alcohol, elaidyl alcohol, linoleylyl alcohol, linoleylyl alcohol, linoleyl alcohol, petol , Gadollyl alcohol, behenyl alcohol and erucyl alcohol and their technical mixtures, which, for example in the high-pressure hydrogenation of technical methyl esters based on fats and oils or aldehydes from Roelen's oxosynthesis and as a monomer fraction in the dimerization of unsaturated fatty alcohols.

Typical examples of fatty acids are caproic acid, caprylic acid, 2-ethylhexanoic acid, capric acid, lauric acid, isotridecanoic acid, myristic acid, palmitic acid, palmoleic acid, stearic acid, isostearic acid, oleic acid, elaidic acid, petroselinic acid, linoleic acid, linolenic acid, aradacholeic acid, elaeoleic acid , 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 in the dimerization of unsaturated fatty acids. Typical examples of fatty alcohol polyglycol ethers are the addition products of 1 to 10 moles of ethylene oxide and 0 to 3 moles of propylene oxide to the above-mentioned fatty alcohols.

Typical examples of fruit acids are lactic acid, malic acid, tartaric acid and citric acid.

The proportion by weight of the above-mentioned further esterification components can be 1 to 10, preferably 2 to 5,% by weight, based on the complex ester.

Catalysts

Due to the high reaction temperatures, the use of catalysts is not absolutely necessary. In particular, the self-condensation of the hydroxy fatty acids is usually autocatalytic. If polyglycerol is used as the polyol component, it usually contains an alkaline catalyst content which is advantageous for the esterification.

If desired, however, the reactions can be accelerated by using catalysts. Alkali and / or alkaline earth compounds such as, for example, sodium hydroxide, sodium carbonate, sodium hydrogen carbonate, potassium hydroxide, potassium carbonate, calcium oxide or magnesium oxide are suitable for this. Other suitable catalysts are tin compounds such as tin oxalate or aluminum compounds such as basic aluminum hydroxide. In principle, mineral acids can also be used However, because of possible elimination reactions, their use is associated with disadvantages.

The catalysts can be used in amounts of 1 to 10, preferably 2 to 5,% by weight, based on the starting materials.

Stabilizers

With regard to light-colored and color-stable products, it has proven to be advantageous to carry out the condensation or esterification in the presence of hypophosphorous acid and / or its alkali metal salts such as sodium hypophosphite as stabilizers. The concentration of these substances can be 0.1 to 5, preferably 0.5 to 2% by weight, based on the starting materials.

Execution of the procedure

The condensation with subsequent esterification is usually carried out in a closed tank with a cooler attached. To this end, the hydroxy fatty acid and, if appropriate, the catalyst and / or the stabilizer are initially introduced, the reactor is closed and the mixture is heated to 200 to 280, preferably 220 to 250 ° C. The desired degree of self-condensation can be determined by the amount of water discharged or by taking samples and determining the acid number. After a reaction time of about 2 to 10 hours, polyhydroxy fatty acids with 2 to 10 and in particular whose 2 to 8 fatty acid units are formed. The following distribution (GPC method) is typically achieved:

Monomers 1 to 10% by weight

Dine 5 to 15% by weight

Trimers 5 to 15% by weight

Tetramers 5 to 15% by weight

Pentamers 5 to 15% by weight

Hexamers 5 to 15% by weight

Heptamers 5 to 15% by weight

Octamers 1 to 10% by weight

Oligomers ad 100% by weight

After the desired acid number has been reached, which is usually in the range from 30 to 80, the preheated polyol component is metered into the reactor using pumps. Due to the high temperatures, the esterification occurs spontaneously, i.e. the water released evaporates suddenly and has to be removed without pressure building up in the reactor. In order to avoid this, the polyol is preferably metered into the reaction batch at such a rate as the water released during the esterification can be removed via the cooler.

The resulting complex esters - insofar as they contain ricinoleic acid units - can be characterized by their iodine number. Typical examples are polyesters with an iodine number <10 (based on 99% 12-hydroxystearic acid) or 70 to 110 (based on 90% 12-hydroxystearic acid, 10% ricinoleic acid). Industrial applicability

The complex esters according to the invention are distinguished by a particularly advantageous emulsifying power. The resulting emulsions have a higher storage and in particular heat stability than the products of the prior art.

They can therefore, optionally in admixture with polyglycerol polyricinoleates, as W / O emulsifiers for cosmetic and / or pharmaceutical preparations such as e.g. Skin creams, body lotions, sunscreens and the like are used, in which they can be contained in concentrations of 1 to 20, preferably 2 to 10% by weight, based on the composition.

The following examples are intended to explain the subject matter of the invention in more detail without restricting it.

Examples

Example 1:

Production of polyglycerol polyricinoleate. 600 kg (2000 mol) of ricinoleic acid were placed in a 1 m ³ boiler with steam heating, a cooler and a water separator, and 3 kg (0.5% by weight) of hypophosphorous acid and 6 kg of sodium hydroxide in the form of a 50 % By weight aqueous solution. The kettle was closed and heated to 250 ° C. with a slight vacuum of about 200 mbar, water of reaction being continuously condensed and removed via the separator. The reaction was continued for 4 h until an acid number of 60 was reached. Subsequently, at a slightly reduced pressure, 90 kg (400 mol) of technical polyglycerol preheated to 90 ° C. was pumped into the boiler at such a rate that the water of reaction formed could be separated off via the cooler. After the addition had ended, the mixture was stirred for a further 2 h, cooled and filtered. A complex ester was obtained which had an average of 8 ricinoleic acid and 4 polyglycerol units and an iodine number of 90 per molecule.

Example 2:

Production of polyglycerol poly-12-hydroxystate. Analogously to Example 1, 600 kg (2000 mol) of 12-hydroxystearic acid were introduced and 3 kg (0.5% by weight) of hypophosphorous acid and 6 kg of sodium hydroxide were added in the form of a 50% by weight aqueous solution. The kettle was closed and heated to 250 ° C. under a slight vacuum of about 200 mbar, water of reaction being continuously condensed and removed via the separator. The reaction was continued for 3 hours until an acid number of 65 was reached. Subsequently, at a slightly reduced pressure, 85 kg (380 mol) of technical polyglycerol preheated to 90 ° C. was pumped into the boiler at such a rate as the water of reaction formed could be separated off via the cooler. After the addition had ended, the mixture was stirred for a further 2 h, cooled and filtered. A complex ester was obtained which had an average of 8 12-hydroxystearic acid and 4 polyglycerol units per molecule.

Example 3:

Production of polyglycerol poly-12-hydroxystearate / polyricinoleate. Analogously to Example 1, 600 kg (2000 mol) of a mixture of 90% by weight of 12-hydroxystearic acid and 10% by weight of ricinoleic acid were introduced and 3 kg (0.5% by weight) of hypophosphorous acid and 6 kg of sodium hydroxide in the form of a 50 wt .-% aqueous solution. The kettle was closed and a slight vacuum of about 200 mbar was applied heated to 250 ° C, water of reaction was continuously condensed and removed via the separator. The reaction was continued for 3 hours until an acid number of 70 was reached. Subsequently, at a slightly reduced pressure, 100 kg (445 mol) of technical polyglycerol, preheated to 90 ° C., was pumped into the vessel at such a rate that the water of reaction formed could be separated off via the cooler. After the addition had ended, the mixture was stirred for a further 2 h, cooled and filtered. A complex ester was obtained which had an average of 8 hydroxy fatty acid and 4 polyglycerol units and an iodine number of 72 per molecule.

Example 4:

Production of trimethylolpropane polyricinol beta. Analogously to Example 1, 600 kg (2000 mol) of ricinoleic acid were introduced and mixed with 3 kg (0.5% by weight) of hypophosphorous acid and 6 kg of potassium hydroxide in the form of a 50% by weight aqueous solution. The kettle was closed and heated to 240 ° C. under a slight vacuum of about 200 mbar, water of reaction being continuously condensed and removed via the separator. The reaction was continued for 4 hours. Then, at a slightly reduced pressure, 100 kg (740 mol) of trimethylolpropane preheated to 90 ° C. was pumped into the vessel at such a rate as the water of reaction formed could be separated off via the cooler. After the addition had ended, the mixture was stirred for a further 2 h, cooled and filtered. Example 5:

Production of polyethylene glycol [200] poly-12-hydroxy stearate. Analogously to Example 1, 600 kg (2000 mol) of 12-hydroxy stearate were introduced and 3 kg (0.5% by weight) of hypophosphorous acid and 6 kg of potassium hydroxide in the form of a 50% by weight aqueous solution were added. The kettle was closed and heated to 240 ° C. under a slight vacuum of about 200 mbar, water of reaction being continuously condensed and removed via the separator. The reaction was continued for 4 hours. Then 42 kg (1700 mol) of polyethylene glycol (average molecular weight 200) preheated to 90 ° C. were also pumped into the vessel at a rate such that the water of reaction formed could be separated off via the cooler. After the addition had ended, the mixture was stirred for a further 2 h, cooled and filtered. A clear, liquid reaction product was obtained.

Claims

claims

1. A process for the preparation of complex esters, in which one

(b) the resulting polyhydroxy fatty acids are esterified with polyols without cooling.

2. The method according to claim 1, characterized in that ricinoleic acid and / or 12-hydroxystearic acid are used as the hydroxy fatty acids.

3. Process according to claims 1 and 2, characterized gekenn¬ characterized in that polyols are used which are selected from the group which is formed by glycerol, alkylene glycols, polyglycerol, methylol compounds, lower alkyl glucosides, sugar alcohols, sugars and / or aminosugar.

4. Process according to claims 1 to 3, characterized gekenn¬ characterized in that a technical polyglycerol mixture of the composition as a polyol

Glycerin 5 to 30% by weight

Diglycerols 15 to 40% by weight

Triglycerols 10 to 30% by weight

Tetraglycerols 5 to 20% by weight

Pentaglycerols 2 to 10% by weight

01igoglycerins ad 100% by weight starts.

5. The method according to claims 1 to 4, characterized gekenn¬ characterized in that small amounts of fatty alcohols, fatty acids, fatty alcohol polyglycol ethers and / or Fruchtsäu¬ ren condensed into the complex esters.

6. Process according to claims 1 to 5, characterized gekenn¬ characterized in that the condensation or esterification is carried out in the presence of catalysts which are selected from the group formed by alkali metal, alkaline earth metal, aluminum and tin compounds becomes.

7. Process according to Claims 1 to 6, characterized in that the condensation or esterification is carried out in the presence of hypophosphorous acid and / or its alkali metal salts.

8. The method according to claims 1 to 7, characterized gekenn¬ characterized in that one carries out the condensation with subsequent esterification in a closed boiler with mounted cooler.

9. The method according to claim 8, characterized in that the preheated polyol is metered into the reaction mixture at such a speed as the water released during the esterification can be removed via the cooler.