AU603467B2 - Polyglycerin esters of the degras acid, a process for their preparation, and their use as emulsifying agents - Google Patents

Description

r 6Q~4 67 S F Ref: 54990 FORM COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 COMPLETE SPECIFICATION

(ORIGINAL)

FOR OFFICE USE: Class Int Class 4 0444 0040 '44 4, 4 44 o 0t' CoMPIetILe Specificaticn Lodged: Accepted: Published,, Priorit~y: Related Art: hi OL..UMCflt con11tL6Iin' t" S,ct in 9 and is corrc'.t I OU riilg.

4 4* 4 1' a 4 4 of Applicant: Address for Service: TH. Goldschrnidt AG Goldschmidtstra~se 100 4300 Essen 1 FEDERAL REPUBLIC OF CGERMANY Spruson Ferguson, Patent Attorneys Level 33 St Martins Tower, 31 Market Street Sydney, New South Wales, 2000, Australia Complete Specification for the invention entitled: Polyglycerin Esters of the Degras Acid, a Process for Their Preparation, and Their Use as Emulsifying Agents The following statement is a full description of this invention, including the best method of performing it known to me/us 5845/3 r~i ua~ :li--

ABSTRACT

Polyglycerin degras acid esters of the general formula

CH

2 -CH-CH20 OR OR

CH

2

-CH-CH

2 OR OR wherein R denotes hydrogen or alkoyl groups derived from the degras acid and the condition that at least one group R is such an alkoyl group is satisfied, and wherein n 0 to 12, and a process of producing these compounds by esterification of polyglycerin with degras acid or transesterification of polyglycerin with wool fat (yolk).

4e 4 9 o Q'r 4ro 446 4.444 4 .4p 4l E The inventive esters, which may contain wool fat alcohols, are efficient emulsifiers especially for cosmetic and pharmaceutical applications.

1 iS 444 44 t I 4 t 4 4 t t 4 9 TO: THE COMMISSIONER OF PATENTS

AUSTRALIA

SBR/TGK/183U TECHNICAL FIELD The invention relates to novel polyglycerin esters of the degras acid and to a process of producing these compounds. The invention also relates to the use of these compounds as emulsifiers, especially for cosmetic and pharmaceutical applications.

BACKGROUND OF THE INVENTION For many decades whole or partial fatty acid esters of polyvalent alcohols have been used for producing physiologically well-tolerated and, hence, readily usable oil/water or water/oil emulsions for cosmetic and pharmaceutical applications.

The fatty acids required were obtained by dissociation of natural fats and oils. In general, fatty acids with 8 18 carbon atoms or corresponding mixtures of fatty acids are employed. The fatty acids may be saturated or unsaturated or, optionally, substituted such as the ricinoleic acid which has

L

5 one OH group. Fatty acids with 10 18 carbon atoms or their mixtures, i i obtained in the dissocation of natural fats, are preferred for esterification. Coconut acids obtained by dissociation of coconut oil are examples.

The mixtures of the fatty acids may be hardened by hydrogenation.

Wool fat, also termed wool wax, is another raw material from which esterifiable carboxylic acids can be obtained and which is available in considerable quantities. Wool fat is a clear-melting, viscous, brownishyellow to black mass with a ram-like scent and is won from raw sheep wool. The degras acids wool wax fatty acids) are obtained by decomposition of esters.

They are a very complicated mixture of fatty acids with straight chains and branched chains. Investigations by Downing et al., Aust. J. Chem., 13 (1960), pp. 80, revealed the presence of the following classes of carboxylic acids: 1. normal series: a) saturated, unsubstituted carboxylic acids about 10 by weight b) a-hydroxycarboxylic acids about 15 by weight c) w-hydroxycarboxylic acids about 3.5 by weight 2. iso-series: a) CH3-CH(CH2) CH2COOH, n 7-25 about 19 by weight

CH

3 b) a-hydroxycarboxylic acids about 12 by weight c) w-hydroxycarboxylic acids about 0.5 by weight 3. anti-iso series:

CH

3

CH

2

CCH

2 CH) CH 2 COOH, n 7-27 about 19 by weight H CH3 .i I The glycerin resulting from the decomposition of fats was initially used as a polyalcohol so that the partial fatty acid esters of glycerin, optionally blended with fatty acid triglycerids, are among the oldest emulsifiers used in the field of cosmetics. The list of useful physiologically well-tolerated polyalcohols was substantially expanded by the industrial production of the hexa-alcohol sorbitol by way of hydrogenation of glucose or by hydrogenolysis of cane sugar or starch. In particular, the monoesters of lauric acid, palmitic acid, stearic acid and oleic acid of sorbitol are used on a large scale for producing cosmetic and pharmaceutical emulsions.

Polyglycerins are another polyol component used. Polyglycerins are usually produced by etherification (condensation) of glycerin at increased temperatures and in the presence of catalysts. The resulting condensation products are predominantly linear and correspond to the formula: CH2-CH-CH2H 2 CH2-CH-CH20 CH 2

-CH-CH

2 II I OH OH OH OH OH In the case of diglycerin, the subscript is x 0. When higher polyglycerins are formed, the subscript x may assume a value between 1 and The polyglycerins can be converted into the corresponding esters with the aid of the usual fatty acids, with the hydrophobic or hydrophilic nature of the products determined by the degree of esterification of the available hydroxyl 20 groups. Synthesis, characterisation, and use of polyglycerin and polyglycerin fatty acid esters have been described in detail in the journal "Die Nahrung" ["Nutrition"] 28 (1984). pp. 815-835. There it has been noted that polyglycerin fatty acid esters are multi-purpose emulsifiers which can be used in the food-processing industry, in medicine, and in dietetics. They are used in the food sector for producing easy-to-spread, edible fats and for producing fat for frying. The polyglycerin fatty acid esters prevent splattering of the hot fat.

The polyglycerin fatty acid esters are also used as emulsifiers in parting agents for producing buiscuits. Polyglycerin fatty acid esters also have been introduced into the cosmetic and pharmaceutical industries. Such applications can be inferred from the journal Soc. Cos. Chem.," 15 (1964), pp. 473 483. Decaglycerins in which 4 10 hydroxyl groups had been esterified with oleic acid or stearic acid proved to be particularly suitable. These products are also used for thickening mineral oils and vegetable oils.

German Patent Application 20 23 786 Laid Open for Public Inspection teaches emulsifiers on the basis of esters which contain degras acids as the -3acid component and glycerin as the polyol component. There [according to that application] they are used as emulsifiers for producing water/oil emulsions.

They may be used as partial or whole esters, optionally together with the wool fat alcohols wool wax alcohols). Partial glycerids with a degree of esterification of 40 60 are cited as preferred glycerids. The resulting wateroil emulsions are stable and can be used for producing cosmetic preparations.

Emulsifiers on the basis of polyglycerids esterified with degras acids have not yet been described. It seems that no unusual properties exceeding the norm were expected from those compounds. Surprisingly, it was found that certain polyglycerin degras acid esters make it possible to produce particularly stable, storable water/oil emulsions and facilitate the introduction, into emulsions, of ingredients which are known to be hard to emulsify. Examples of such substances which often are hard to emulsify are especially perfume oils Ssuch as a- and y-terpineol.

15 SUMMARY OF THE INVENTION Therefore, one objective of the present invention are novel polyglycerin i degras acid esters of the general formula

CH

2

-CH-CH

2 0 CH 2 -CH-CH0 C-CH-CH I

I

OR OR OR OROR I n Swherein R denotes hydrogen or alkoyl groups derived from the degras acid, wherein the condition that at least one group R is such an alkoyl group is satisfied, and wherein n 0 to 12.

Polyglycerin degras acid esters in which the subscript assumes a value between 1 and 8, specifically between 4 and 8, are particularly preferred.

The best emulsifying properties are obtained when at least 50% of the groups R are formed by alkoyl radicals derived from the degras acid.

The polyglycerin degras acid esters of the invention are wax-like to firm, yellow to brown compounds. Their colour can be brightened by the conventional oxidizing treatment used in the preparation of fatty acid esters and/or by adsorption, with the aid of activated charcoal or bleaching earth. The melting points of the esters are between 35 and 60 "C.

The polyglycerin degras acid esters of the invention have the desired high emulsifying capability for substances which are hard to emulsify and allow the manufacture of stable and storable water/oil emulsions. This emulsifying ability could not be derived from the properties of the degras acid and the polyglycerin, respectively, nor of the conventional wool fatty acid esters of glycerin.

TR- 4 1 Another advantage of the compounds according to the invention results from the possibility of preparing products of various molecular weights but of the same or similar HLB values. For example, an inventive ester with the subscript n 2 and with 50% of the hydroxyl groups esterified with degras acid has an HLB value of about 4.4. An inventive ester with the subscript n 6 and the same degree of esterification has an HLB value of about 4.9.

Through the different degrees of condensation of the two products and, hence, their different molecular weights (1385 2395) and the different numbers of ester groups in the molecule, the emulsifying efficiency of the emulsifier can be optimally adjusted to the substrate to be emulsified.

According to another objective of the invention, the polyglycerin degras acid esters of the invention and the above formula can be prepared by esterifying polyglycerin of the general formula O, CH 2 -CH-CH2 CH 2 -CH-CH CH -CH-CH OH OH OH OH OH ,r 5 with at least equimolar amounts of degras acid, in a manner known per se, in the presence of esterifying catalysts at temperatures between 140 and 280"C.

State-of-the-art catalysts such as alkali hydroxides, alkali carbonates, alkali salts of fatty acids, and compounds of titanium or tin can be employed as esterifying catalysts.

The water which is liberated in the esterification process is conveniently removed by distillation in the course of the reaction and, in particular, removed in azeotropic fashion. The esterification reaction proceeds at temperatures between 140 and 280°C. It proceeds in a manner 'known per se.

However, it is also possible to obtain a direct reaction between wool fat in native or purified form and polyglycerin. Therefore, another objective of the present invention relates to a process with the characterising feature that wool fat is transesterified in a manner known per se, with polyglycerin of formula II, in the presence of a transesterifying catalyst, at temperatures between 100 and 300°C, and that the wool fat alcohols liberated are optionally separated either continuously or after transesterification in a manner known per se. However, it turned out that the expensive removal of the wool fat alcohols is not always required when the esters of the invention are used in cosmetics because the wool fat alco- 411--i--ilY hols themselves have excellent emulsifying and skin-care properties. This implies a reduction of the costs of the product.

The above-cited state-of-the-art catalysts can be used as transesterification catalysts, with catalysts implying an alkaline reaction being preferred.

In view of the excellent emulsifying properties and the physiological tolerability of the compounds according to the invention, another objective of the invention is the use of the compounds, optionally blended with wool fat alcohols, as emulsifiers for preparing water/oil emulsions for cosmetic and pharmaceutical applications. The emulsifying agents according to the invention can be easily worked and are effective even in small amounts.

They have a strong emulsifying effect even vis-a-vis compounds the poor emulsifiability of which is notorious. Among them there are, for example, some perfume oils and pharmaceutically active compounds. The preparations can be easily spread on the skin and are rapidly absorbed by it. The compounds proper have skin-care properties, are physiologically harmless, and are accepted without irritation even by sensible skin.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS The following examples illustrate the preparation of compounds ."2D according to the invention, their properties, and their applications.

Polyglycerins of formula II and the following characteristics are used to prepare the compounds of formula I in accordance with the invention: polyglycerin n value OH number triglycerin 1 1160 1197 hexaglycerin 4 960 1000 decaglycerin 8 885 890 Degras acid with the following characteristics is used: saponification number 140 185 acid number 120 165 hydroxyl number 50 melting point* 45 60 "C The wool fat used has the following parameters: saponification number 88 102 acid number max. hydroxyl number 20 iodine number 18 32 non-saponifiable 45 meltina point* 36 42 "C *According to Ubbelohde -6i i i Preparation of Compounds of Formula I According to the Invention 1. Reaction of polyglycerins with degras acids Preparation of triglycerin-tri-degras acid ester: n 1; 40 of the groups R are formed by 60 1 of the groups R are alkoyl radicals derived from the degras acid.

240 g triglycerin (1 mole) together with 1290 g degras acid (3 moles) are weighed out and filled into a three-necked bottle provided with a stirrer, an inlet tube, a bridge-type cooler, and a receiver. The reagent mixture is heated within an hour to the reaction temperature 250 255 °C while N 2 is introduced, and the reaction is allowed to proceed for 6 hours while the volatile reaction products are removed by distillation. The acid number decreases to 3.0. 86 g distillate are obtained.

The reaction product is brown to dark brown and has a wax-like consis- SI tency and the following characteristics: acid number 0 0 saponification number 120 hydroxyl number 84 S melting point 53 °C Preparation of hexaglycerin-hexa-degras acid ester: n 4; 25 of the groups R are formed by 75 of the grouos R are alkoyl radicals derived from the degras acid.

78 g hexaglycerin (0.167 moles) are esterified with 480 g degras acid (1 mole) as in the above example. The reaction temperature is 250 252 °C.

By the end of the reaction the acid number of the reaction product is 34 g distillate are obtained.

The brown, wax-like reaction product has the following characteristics: acid number saponification number 132 hydrqxyl number 48 melting point 51 °C Preparation of decaglycerin-octa-degras acid ester: n 8; 25 of the groups R are formed by 75 of the groups R are alkoyl radicals derived from the degras acid.

7- 67 g decaglycerin (0.087 moles) are esterified with 333 g degras acid (0.694 moles) as in the above example. By the end of the reaction the acid number is 1.0. 24 g distillate are obtained.

The brown, wax-like reaction product has the following characteristics: acid number saponification number hydroxyl number melting point 120 67 52 °C 0 0 1000 0010 0 Other compounds of the invention were prepared in the manner described above; their characteristics have been compiled in the following table.

R groups Melting n (alkoyl) Acid No. Saponification No. Hydroxyl No. Point 1 20 1.8 96 350 57 1 40 2.0 116 162 54 1 60 3.0 120 84 51 1 80 4.0 126 42 51 4 12.5 0.9 75 448 4 37.5 1.0 113 171 42 4 62.5 1.2 128 76 39 4 75 1.0 132 62 39 4 87.5 0.9 134 42 48 4 100 1.0 142 36 48 8 8.3 1.1 64 542 8 25 1.5 89 244 8 33.3 1.0 107 134 53 8 41.6 1.6 108 143 53 8 50 2.6 132 104 8, 66.6 2.6 121 60 51 8 83.3 1.0 123 58 51 8 100 0.9 127 50 51 8 2. Reaction of polyglycerins with wool fat U Preparation of decaglycerin wool fat ester (without catalyst) 108.5 g decaglycerin together with 685 g wool fat are weighed out and filled into a three-necked bottle provided with a stirrer, an inlet tube, a S 5 bridge-type cooler, and a receiver. The reagent mixture is heated within an hour to the reaction temperature 240 250 °C while N 2 is introduced, and the reaction mixture is kept for 20 hours at this temperature without !I adding a catalyst. There is no distillate.

The resulting brown, wax-like product has the following characteristics: a:id number saponification number hydroxyl number melting point 0.4 51 68 40 °C Preparation of decaglycerin wool fat ester (with catalyst) 259 g wool fat and 41 g decaglycerin are weighed out and filled together with 1.5 Na stearate as a catalyst into an above-described apparatus. The reagent mixture is heated within an hour to the reaction temperature 240 250 °C while N 2 is introduced, and the reaction mixture is kept for 2.5 hours at this temperature. 1.5 Na methylate are added as an additional catalyst. The reaction is allowed to proceed for another 2 hours. 6.2 g distillate are obtained.

The reaction product is dark brown and wax-like and has the following characteristics: acid number 0.9 saponification number hydroxyl number 49 melting point 41 °C Preparation of decaglycerin wool fat ester (with catalyst) 129.5 g wool fat and 20.5 g decaglycerin are mixed with 1.5 g Na methylate and enter into the reaction in the above-described apparatus. The reaction takes place at 290 300 °C within a time of 2 hours. 6.8 g distillate are obtained.

The brown, wax-like reaction product has the following character- 3 istics: acid number 1.4 saponification number 42 hydroxyl number 29 melting point 40 °C The properties of the compounds of the invention are tested for i applications with the following methods: i. Emulsification number: The emulsification number is a measure for the water-absorption capacity of an emulsifying agent and indicates how many millilitres water i 10 can be entered by emulsification into 100 g of a 5 solution of the ji emulsifying agent in paraffin oil.

Procedure: i 1.0 g of the emulsifying agent to be tested is hot-dissolved in 19.0 g j liquid paraffin oil (DAB 9 brand). After that, 10 g are filled into a 15 mechanical mixer and heated to 50 Then 5 millilitre warm water of 50 °C are added while continuously stirring with 150 rpm.

|i Addition is continued in one-minute intervals until the resulting emulsion no longer absorbs water.

Emulsification number millilitres H20 used x S 2C Perfume number: The perfume number is a measure for the perfume-absorption capacity of an emulsion and indicates how many millilitres perfume can be entered by emulsification into 100 g of an emulsion (creme/lotion). The composition of the creme is stated below.

Procedure: 100 g emulsion are weighed out and filled at room temperature into a manual emulsifying machine (ramming unit). Then perfume oil is added in millilitre portions and the ram is actuated 30 times for each portion.

Then the creme is evaluated in regard to separation of oil and water. The procedure is repeated until the creme can no longer absorb perfume without separation of water or oil.

Perfume number millilitre perfume oil used.

10 Composition of the creme used for determining the perfume number and the stability of the emulsion: fatty phase: paraffin oil vaseline fully refined wax (dripping point 105 "C) ceresine cetyl-stearyl alcohol emulsifying agent aqueous phase: water Mg 2

SO

4 .7H 2 0 glycerin perfume oil per cent by weight 2 2 3 60.8 0.2 Procedure: The fatty phase is mixed at 105 °C and thereafter weighed out and filled into a manual emulsifying machine (ramming unit). After cooling to the aqueous phase is addedand the resulting creme is homogenised.

After cooling to 40 *C and the addition of the perfume oil, the ram is actuated 50 times in vacuum. The machine is ventilated, evacuated again, and the ramming is repeated 50 times. Shelf stability of the creme is tested after 24-hour storage at =40, -10, -20 and at room temperature.

means no separation of oil and/or water, means separation of oil and/or water.

11

LI

ill I. Products Prepared by Transesterif ication R groups Emulsification Perfume Shelf Stability n (alkoyl) Number Number ±4000 -O0'C -20*C RT 120 525 6.75 140 725 6.0 1 >160 800 7.0 180 625 6.0 4 12.5 275 5.25 4 37.5 575 6.0 4 62.5 725 7.0 4 75 750 8.5 4 87.5 700 8.25 4 100 500 8.0 8 8.3 450 5.0 8 25 625 5.5 8 33.3 700 6.0 8 41.6 925 8.5 1 8 50 850 ca. 35 1 8 66.6 900 ca. 20 8 83.3 700 ca. 20 8 100 550 ca. 15 2. Products Prepared by Transesterification Transesterific. Emulsification Perfume Shelf Stability of the Wool Fat Number Number +40'C -100C -200C RT with decaglycerin 800 20 wi tnouL catal yst decaglycerin 850 24 with catalyst *Temperature of reaction 250*C decaglycerin 700 34 with catalyst Temperature of reaction 290 0

C

3. -COMPARATIVE

FIGURES

Wool fat 450 Wool fat alcohol 550 3.0 T Mixture of wool fat and decaalvcerin inhomogeneous, orecipitate. measurements not oossible 12

Claims (9)

1. Polyglycerin degras acid esters of the general formula CH -CH-CHO CH 2 -CH-CH 2 O CH 2 -CH-CH R OR OR OR OR n wherein R denotes hydrogen or alkoyl groups derived from the degras acid and the condition that at least one group R is an alkoyl group, and wherein n 0 to 12.

2. The polyglycerin degras acid esters according to Claim 1, characterised in that at least 50% of the groups R are formed by alkoyl radicals derived from the degras acid and n 4 to 8. o°o 0

3. A process of preparing the compounds of Claim 1 or Claim 2, S characterised in that polyglycerin of the general formula 0 CH 2 -CH-CH20 CH 2 -CH-CH2 CH 2 -CH-CH 2 OH OH OH OH OH X is esterified, in a manner known per se, with at least equimolar amounts of o degras acid in the presence of esterification catalysts, at temperatures of 140 2800C.

4. The process for preparing the compounds of Claim 1, characterised in that wool fat is transesterified, in a manner known per se, with polyglycerin of the general formula CH 2 -CH-CH20 CH 2 -CH-CH20 CH 2 -CH-CH 2 OH OH OH OHOH x in the presence of transesterification catalysts at temperatures between 100 and 300°C and that, optionally, continuously, or after transesterification, the wool fat alcohols liberated are separated in a manner known per se.

Use of the compounds of Claim 1 or Claim 2 or mixtures thereof with wool fat alcohols as emulsifying agents. 13 RLF/0871y _L I i~ i _1 1~1 i:il _QII_

6. Use according to Claim 5 in cosmetic or pharmaceutical applications.

7. Polyglycerin degras acid esters, substantially as hereinbefore described with reference to any one of the Examples.

8. A process of preparing a polyglycerin degras acid ester, substantially as hereinbefore described with reference to any one of the Examples.

9. Use of a polyglycerin degras acid ester of claim 7 or mixtures thereof with wool alcohols as emulsifying agents, substantially as hereinbefore described with reference to any one of the Examples. DATED this SEVENTH day of AUGUST 1990 TH. Goldschmidt AG Patent Attorneys for the Applicant SPRUSON FERGUSON I -14- RLF/0871y z