DE4442988C1 - Prepn. of complex ester useful as emulsifier for pharmaceutical etc. - Google Patents

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 DEG C; and (b) the resulting polyhydroxy fatty acids are esterified with polyols without being allowed to cool.

Description

Field of the Invention

The invention relates to a method for producing Complex esters, in which one initially with hydroxy fatty acids subject to high temperatures of self-condensation and then the resulting polyhydroxy fatty acids without Cooling esterified with polyols.

State of the art

Are complex esters of the polyglycerol polyricinoleates type has long been known as W / O emulsifiers and can be used for For emulation of low-viscosity W / O emulsions the [cf. EP-A1 0559013 (Th. Goldschmidt), EP-A1 0440203 (Lotte Co.) and WO 85/04346 (Meÿi Milk Prods.)].

Glycerol is usually first used for their production and ricinoleic acid polymerized separately and the polymers then esterified with each other. This procedure is true realized on a technical scale, but with a high level technical effort with regard to separate boilers or Boiler occupancy times connected.  

In principle, it is also possible to use glycerin or polyglycerin and ricinoleic acid together and the condensate tion and the esterification simultaneously or side by side to let go. However, it turns out that the esterification runs faster and the proportion of polymeric ricinoleic acids in Most complex is low.

The object of the invention was thus a ver Improved process for the production of polyol polyhydroxy to provide fatty acid esters that are free of the disadvantages described.

Description of the invention

The invention relates to a method for producing of complex esters where one

• (a) Hydroxy fatty acids at temperatures in the range of 200 subject to self-condensation up to 280 ° C and
• (b) the resulting polyhydroxy fatty acids without cooling esterified with polyols.

Surprisingly, it was found that complex esters with a high proportion of polymeric hydroxy fatty acids with mini can produce a lot of technical effort if you first which produces polyhydroxy fatty acids and into the hot reacti the esterification component. A be special advantage when using polyglycerol as polyol be is also the fact that the polyglycerol usually a residual alkaline catalyst content due to the position  has in the esterification with the polyhydroxy fatty acid is very useful.

Hydroxy fatty acids

In particular, ricinoleic acid and 12-hydroxystearic acid and mixtures thereof. The latter can be done by mixing the two components or partial curing of ricinoleic acid can be produced.

Polyols

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

• - glycerin,
• - Alkylene glycols such as ethylene glycol, Di 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 especially 1 to 4 carbons in the alkyl radical such as for example methyl and butyl glucoside;
• - Sugar alcohols with 5 to 12 carbon atoms as in for example 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 will.

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)% by weight
Diglycerins: 15 to 40 (20 to 32) wt%
Triglycerins: 10 to 35 (15 to 25)% by weight
Tetraglycerols: 5 to 20 (8 to 15)% by weight
Pentaglycerins: 2 to 10 (3 to 8) wt%
Oligoglycerins: ad 100% by weight.

The production of a polyglycerol of the above composition can by self-condensation of glycerol in Presence of suitable catalysts such as Potassium carbonate, silicates according to DE-A1 4029323 (Henkel) or Borates according to DE-A1 4117033 (Henkel) at temperatures in the loading range from 200 to 260 ° C.  

Other esterification components

It is possible to add further alcohols or Carboxylic acids such as B. fatty alcohols, fatty acids, fatty alcohol condense polyglycol ether and / or fruit acids.

Typical examples of fatty alcohols are Capronalcohol, Ca. pryl alcohol, 2-ethylhexyl alcohol, capric alcohol, lauryl alcohol nol, isotridecyl alcohol, myristyl alcohol, cetyl alcohol, palm oleyl alcohol, stearyl alcohol, isostearyl alcohol, oleyl alcohol hol, elaidyl alcohol, petroselinyl alcohol, linolyl alcohol, Linolenyl alcohol, elaeostearyl alcohol, arachyl alcohol, Gado leyl alcohol, behenyl alcohol and erucyl alcohol and their technical mixtures, e.g. B. in high pressure hydrogenation of technical methyl esters based on fats and oils or aldehydes from Roelen's oxo synthesis and as Monomer fraction in the dimerization of unsaturated fat alcohol.

Typical examples of fatty acids are caproic acid, capryl acid, 2-ethylhexanoic acid, capric acid, lauric acid, isotri decanoic acid, myristic acid, palmitic acid, palmoleic acid, Stearic acid, isostearic acid, oleic acid, elaidic acid, petro selinic acid, linoleic acid, linolenic acid, elaeostearic acid, Arachidic acid, gadoleic acid, behenic acid and erucic acid as well whose technical mixtures, the z. B. in pressure splitting of natural fats and oils, in the reduction of Al dehyden from Roelen's oxosynthesis or dimerization unsaturated fatty acids.  

Typical examples of fatty alcohol polyglycol ethers are Addition products of 1 to 10 moles of ethylene oxide and 0 to 3 Moles of propylene oxide to the above fatty alcohols.

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

The weight fraction of the above-mentioned further esterification Components can be based on the complex ester 1 to 10 preferably 2 to 5 wt .-%.

Catalysts

As a result of the high reaction temperatures, it is also used of catalysts not absolutely necessary. Especially the self-condensation of the hydroxy fatty acids takes place in the Usually autocatalytic. Will polyglycerol as a polyol component used, it usually contains manufacturing contains a content of alkaline catalysts, which for the Esterification is beneficial.

If desired, however, the reactions can be carried out using the accelerated the use of catalysts. Therefor come alkali and / or alkaline earth compounds such as wise sodium hydroxide, sodium carbonate, sodium hydrogen carbo nate, potassium hydroxide, potassium carbonate, calcium oxide or magne silicon oxide in question. Make other suitable catalysts Tin compounds such as tin oxalate or aluminum compounds such as basic aluminum hydroxide Mineral acids can in principle also be used  due to possible elimination reactions is their ver However, there are disadvantages.

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

Stabilizers

With regard to light colored and color stable products it has condensation or esterification have proven to be advantageous tion in the presence of hypophosphorous acid and / or its Alkali salts such as sodium hypophosphite as Sta perform bilisators. The concentration of these substances can 0.1 to 5, preferably 0.5 to 2 wt .-% - based on the input materials - amount.

Execution of the procedure

The condensation with subsequent esterification is usually carried out in a closed boiler with an attached cooler. For this purpose, 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 egg condensation can be determined by the amount of water discharged or by sampling and determining the acid number. After a reaction time of about 2 to 10 h, polyhydroxy fatty acids with 2 to 10 and in particular 2 to 8 fatty acid units are formed. The following distribution (GPC method) is typically achieved:
Monomers: 1 to 10% by weight
Dimers: 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 reaching the desired acid number, which is usually is in the range of 30 to 80, the preheated polyol component metered into the reactor via pumps. As a result of At high temperatures, the esterification occurs spontaneously. H. the released water evaporates suddenly and must be removed without pressure building up in the reactor. To do this to avoid, the polyol is preferably with such Speed dosed into the reaction batch like that water released during esterification via the cooler can be performed.

The resulting complex esters can - as far as Rici contain nolic acid units - characteristic of their iodine number be settled. Typical examples are polyester with a Iodine number <10 (based on 99% 12-hydroxystearic acid) or 70 to 110 (base 90% 12-hydroxystearic acid, 10% ricinoleic acid).  

Industrial applicability

The complex esters according to the invention are notable for particularly advantageous emulsifying power. The result emulsions have a compared to the products of State of the art higher storage and especially heat buildup bility.

You can therefore, if necessary in a mixture with Polyglyce rinpolyricinoleates, as W / O emulsifiers for cosmetic and / or pharmaceutical preparations such. B. skin creams, Kör pearl lotions, sunscreens and the like are used in which they are present in concentrations of 1 to 20 preferably 2 to 10 wt .-% - based on the agent - contain can be.

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

Examples example 1 Production of polyglycerol polyricinoleate

In a 1 m³ Boiler with steam heating, attached cooler and water drain 600 kg (2000 mol) of ricinoleic acid were initially charged and with 3 kg (0.5% by weight) of hypophosphorous acid and 6 kg of sodium umhydroxid in the form of a 50 wt .-% aqueous solution ver puts. The kettle was closed and put on one light vacuum of about 200 mbar heated to 250 ° C, wherein Condensed water of reaction continuously via the separator was removed and removed. The reaction continued for 4 hours set until an acid number of 60 was reached. Then 90 kg (400 mol) was also at reduced pressure Technical polyglycerol preheated to 90 ° C with a pumped into the boiler at the same speed as that The water of reaction is separated out via the cooler could. After the addition had ended, the mixture was stirred for a further 2 h stirred, cooled and filtered. It became a complex ester obtained, the average per molecule 8 ricinoleic and 4 polyglycerol units and an iodine number of 90.  

Example 2 Production of polyglycerol poly-12-hydroxystearate

Analogously to Example 1, 600 kg (2000 mol) of 12-hydroxystearic acid submitted and with 3 kg (0.5 wt .-%) of hypophosphorous acid and 6 kg of sodium hydroxide in the form of a 50% by weight aqueous Solution added. The kettle was closed and under An apply a slight vacuum of approximately 200 mbar to 250 ° C heats, with water of reaction continuously over the separator which was condensed and removed. The reaction was over 3 h continued until an acid number of 65 was reached. On finally 85 kg was also reduced pressure (380 mol) technical polyglycerol preheated to 90 ° C pumped into the boiler at such a speed as the water of reaction formed is separated off via the cooler could be. After the addition was complete, the batch stirred for a further 2 h, cooled and filtered. It became a Complex ester obtained, the average per molecule 8 Has 12-hydroxystearic acid and 4 polyglycerol units.

Example 3 Production of polyglycerol poly-12-hydroxystearate / polyrici noleate

Analogously to Example 1, 600 kg (2000 mol) of a Mi mixture of 90% by weight of 12-hydroxystearic acid and 10% by weight Ricinoleic acid submitted and with 3 kg (0.5 wt .-%) hypophospho acid and 6 kg of sodium hydroxide in the form of a 50% by weight aqueous solution. The kettle was closed and applying a slight vacuum of approximately 200 mbar  heated to 250 ° C, water of reaction continuously over the separator has been condensed and removed. The reaction was continued for 3 h until an acid number of 70 was reached has been. Then was slightly reduced Pressure 100 kg (445 mol) technical preheated to 90 ° C Polyglycerin at such a rate in the kettle pumped like the water of reaction formed over the cooler could be separated. After the addition was complete the mixture was stirred for a further 2 h, cooled and filtered. It a complex ester was obtained, which on average per month lekül 8 hydroxy fatty acid and 4 polyglycerol units as well had an iodine number of 72.

Example 4 Production of trimethylolpropane polyricinoleate

Analog at game 1, 600 kg (2000 mol) of ricinoleic acid were introduced and 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 puts. The kettle was closed and put on one light vacuum of about 200 mbar heated to 240 ° C, wherein Condensed water of reaction continuously via the separator was removed and removed. The reaction continued for 4 hours set. Then was slightly reduced Pressure 100 kg (740 mol) trimethylolpro preheated to 90 ° C pan pumped into the cauldron at such a speed, how the water of reaction formed shoots over the cooler that could be. After the addition was complete, the An stirred for a further 2 h, cooled and filtered.  

Example 5 Production of polyethylene glycol [200] poly-12-hydroxystea advice

Analogously to Example 1, 600 kg (2000 mol) of 12-hydroxy Stearate presented and with 3 kg (0.5 wt .-%) hypophosphorous Acid and 6 kg of potassium hydroxide in the form of a 50 wt .-% aqueous solution. The kettle was closed and with a slight vacuum of about 200 mbar Heated 240 ° C, water of reaction continuously over the Separator was condensed and removed. The reaction was continued over 4 h. Then it was also easy reduced pressure 42 kg (1700 mol) preheated to 90 ° C Polyethylene glycol (average molecular weight 200) pumped into the boiler at such a speed as the water of reaction formed is separated off via the cooler could be. After the addition was complete, the batch stirred for a further 2 h, cooled and filtered. It became a Obtain clear, liquid reaction product.

Claims (9)

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

• (a) subjecting hydroxy fatty acids to self-condensation at temperatures in the range from 200 to 280 ° C. and
• (b) the resulting polyhydroxy fatty acids are esterified without cooling with polyols.

2. The method according to claim 1, characterized in that one as hydroxy fatty acids ricinoleic acid and / or 12-Hy uses droxystearic acid. 3. The method according to claims 1 and 2, characterized shows that one uses polyols that are selected from the group formed by glycerin, alky lenglycols, polyglycerol, methylol compounds, never drigalkylglucosides, sugar alcohols, sugars and / or Aminosugars. 4. Process according to claims 1 to 3, characterized in that a technical Polyglyce ringemisch the composition as a polyol
Glycerin: 5 to 30% by weight
Diglycerins: 15 to 40% by weight
Triglycerins: 10 to 30% by weight
Tetraglycerins: 5 to 20% by weight
Pentaglycerins: 2 to 10% by weight
Oligoglycerins: ad 100% by weight
starts. 5. The method according to claims 1 to 4, characterized records that you have small amounts of fatty alcohols, fat acids, fatty alcohol polyglycol ethers and / or fruit acid condensed into the complex esters. 6. The method according to claims 1 to 5, characterized records that the condensation or esterification in Performs presence of catalysts that are selected are from the group that is formed by alkali, Alkaline earth, aluminum and tin compounds. 7. The method according to claims 1 to 6, characterized records that the condensation or esterification in Presence of hypophosphorous acid and / or its Al carries out potash salts. 8. The method according to claims 1 to 7, characterized records that the condensation with subsequent Esterification in a closed boiler with open cooler. 9. The method according to claim 8, characterized in that the preheated polyol at such a speed dosed into the reaction mixture, like the one at water released from the esterification via the cooler can be performed.