GB2279948A

GB2279948A - Ricinoleic acid derivative

Info

Publication number: GB2279948A
Application number: GB9312769A
Authority: GB
Inventors: Suk Hyung Cho; Sudhir Bhagwat Kulkarni
Original assignee: Unilever PLC
Current assignee: Unilever PLC
Priority date: 1993-05-07
Filing date: 1993-06-21
Publication date: 1995-01-18
Also published as: GB9312769D0

Abstract

A compound of formula <IMAGE> wherein:- M is selected from hydrogen, all alkali metal, ammonium and an alkylamine; and R is a linear or branched alkyl group containing 1 to 30 carbon atoms; is prepared from reacting ricinoleic with an acylating agent. The process is carried out at low temperatures and without solvents or catalysts.

Description

This invention relates to the preparation of 12-0-alkanoyl ricinoleic acid and the salts and derivatives thereof and novel compositions incorporating the same.

Castor oil is an abundant non-edible oil resource. There have been many efforts to utilize this bountiful cheap resource in the area of soaps and detergents. The processed castor oil (castor olein! is currently used at 30-352 level in popular toilet and premium soaps. The major component of castor oil is ricinoleic acid (9O%) and the saponification of castor oil results in castor soap/ricinoleate soap.

Sodium ricinoleate (Sodium R-12-hydroxy-cis-9-octadecenoatel, a castor soap, is an interesting bipolar surfactant with terminal and midchain polar groups. Extensive studies on fundamental physico-chemical properties of sodium ricinoleate have been recently reported and the studies show that the hydroxyl group of ricinoleate plays an important role in its solution properties. Because of the hydroxyl group, sodium ricinoleate behaves like a short chain soap.

Although some attempts were reported to have been made to protect the hydroxyl group of ricinoleate for improving its soap characteristics, the use of ester groups was never investigated. The present invention proposes the modification of the hydroxy group of ricinoleate to more hydrophobic moeities by esterification thereby achieving more performance advantage for use in soap snd other personal products.

The synthesis of acylated ricinoleic acid have already been reported. One such known method is the treatment of ricinoleic acid with acyl chloride in the presence of pyridine. According to another known method, the ricinoleic acid is treated with acetic anhydride at elevated temperatures o of about 100-150 C. However, none of these methods achieve the desired selective modification of the hydroxyl group. Ricinoleic acid has two nucleophilic sites for acylation, the hydroxyl group and the carboxyl group. Typically, most of the known methods suggest the use of excess acylating agent, as a consequence of which the carboxyl group also gets attacked thereby resulting in the formation of undesired mixed anhydride.

The present invention proposes an efficient and selective synthesis of 12 Q-alkanoyl ricinoleic acid and the salts and derivatives thereof. Unlike the conventional methods, the present process may be carried out without any solvents or catalyst (e.g., pyridine! and that too at low temperatures, o preferably from 0 e to ambient temperature. The rate of the esterifying/acylating agent may also be controlled in order to minimise the formation of mixed anhydride which is undesirable. Surprisingly, by controlling the parameters as above, it is now possible to achieve selectivity of hydroxyl Oacylation over carboxyl Q-acylation.

Accordingly, the present invention provides a process for preparing

compounds of the following formula: o R v\-o wherein M is hydrogen, alkali metal, ammonium or an alkylamine such as triethanolamine and R is an alkyl group, linear or branched, containing 130 carbon atoms, comprising treating ricinoleic acid with an acylating agent, wherein the mole ratio of the ricinoleic acid to the acylating agent is from 0.75 to 1.5. preferably from 0.9 to 1.1, and the treatment is o carried out mildly at a temperature from 0-35 C.

The invention will now be illustrated with reference to the following nonlimitative examples.

Example I PreDaration of 12-O-ethanoyl-9-cis-octadecenoic acid !12-O-acetoxv ricinoleic acids Ricinoleic acid (12.6 : 0.042 mole) and acetic anhydride (10.8 g, 0.106 mole! were added to a round bottom flask equipped with a stirrer and a drying tube. The reaction was stirred at room temperature and was followed by thin layer chromatography against starting material (hexane:ether/90:10). The conversion was complete in 6 hrs. Excess acetic anhydride and acetic acid were stripped off by vacuum at room temperature to give a clear oil (13.4 g, 93.2% conversion).

A column was packed with 175 n of silica in hexane. The column was loaded with 13.4 c. of crude material, and it was eluted with hexane and then with hexane:ether mixture. The tic indicated pure fractions which were collected and solvents removed in vacuum to give a clear oil !9.5 g, 66.1% yield).

Preparation of sodium 12-O-ethanoyl-9-cis-octadecenoate (Sodium 12-O acetoxv ricinoleatel To a reaction flask containing O-acetoxyricinoleic acid (7.0 g), NaOH solution (0.8 Q NaOH in 24 mL of distilled water! was slowly added. The o temperature was maintained at 25 C and pH was adjusted to 10.5. Water was removed by vacuum, and the material was crystallized out from acetone. The material was filtered and recrystallized in water/acetone to give a white solid (6.5 g, 87.2x yield? mass.

Example II PreDaration of 12-O-propionyl-9-cis-octadecenoic acid Ricinoleic acid (5.96 g, 0.02 mole) and propionyl chloride (3.7 g, 0.04 mole) were stirred at room temperature for 3 hrs. The excess propionyl chloride was removed by vacuum to give 6.7 g of crude oil. A similar column filtering was performed on 19.4 c of crude oil to give 11.0 g of Opropionyl ricinoleic acid.

Preparation of sodium 12-O-propionyl-9-cis-octadecenoate A similar neutralization process and work. up as previously described was performed on 9.5 Q of O-propionylricinoleic acid to give 9.0 Q of a white solid (89.2% vield) mass.

Example III PreDaration of 12-O-butanoyl-9-cis-octadecenoic acid Ricinoleic acid (7.45 g, 0.025 molel and butanoyl chloride (4.0 g, 0.0375 mole) was reacted and worked up in a similar fashion as described above to give 9.3 g of crude product. After the column filtration, 7.5 g of pure oil was recovered.

Preparation of sodium 12-0-butanovl-9-cis-octadecenoate Butanoyl ricinoleic acid (6.5 g) was converted to sodium salt in a similar fashion described above. After the recrystallization, 5.0 g of salt was obtained (78.4t yield).

Example IV Preparation of 12-0-hettanovl-9-cis-octadecenoic acid Ricinoleic acid (11.92 g, 0.04 mole) was reacted with heptanoyl chloride (8.92 g, 0.06 mole) to give 18.95 g of crude oil. After the column filtration, 18.0 g of purified material was recovered.

Prenaration of sodium 12-0-hestanovl-9-cis-octadecenoate 12 g of heptanoyl ricinoleic acid was neutralised to give 7.4 g (58.5t after recrystallization) of a desired salt.

Example V Pretaration of 12-0-dodecanovl-9-cis-octadecenoic acid 29.8 g (0.1 mole) of ricinoleic acid was reacted with 24.04 g (0.11 mole) of lauryl chloride at room temperature for 5 hrs to give 49.7 g of crude material. The crude material (49 g) was filtered through a silica column using eluent described above. After the removal of solvent, 44 g of purified product was obtained.

Pretaration of sodium 12-0-dodecanovl-9-cis-octadecenoate 12 g of 0-dodecanoyl ricinoleic acid obtained was neutralised to give 10.6 g of the desired salt.

The products obtained were analysed and tested, and the results are shown in the following Table I.

Table 1. Physical and Analytical Data of 0-Alkanoyl ricinoleic Acid, and the Salts.

Entry Substrates Physical M.P. ( C) IR (vc=0, 1H NMR Appearence in cm-1 1 Sodium 0-ethanoyl White solid 185 (dec.) 1739 (s), 5.53 (m, 1H) 5.35 (m, 1H) ricinoleate 1563 (s) 4.8 (m, 1H) 2.33 (m, 2H) 2.13 (t, 2H) 2.03 (s, 2H) 2.0 (s, 3H) 1.54 (br.s, 4H) 1.27 (br.s, 18H) 0.87 (br.t, 3H) 2 0-Ethynoyl Clear liquid . . . . . . . . . 1736 (s), 5.46 (m, 1H) 5.34 (m, 1H) ricinoleic Acid 1710 (br.s) 4.86 (p, 1H) 2.35 (t, 2H) 2.28 (m, 2H) 2.03 (s, 3H) 2.0 (m, 2H), 1.63 (m, 2H) 1.54 (m, 2H) 1.3 (br.s, 18H) 0.88 (t, 3H) 3 Sodium 0-propinoyl White solid 190 (dec.) 1733 (s), 5.48 (m, 1H) 5.35 (m, 1H) ricinoeate 1561 (s) 4.85 (m, 1H) 2.3 (br.q, 2H) 2.1 (br.t, 2H) 2.0 (br.s, 2H) 1.3 (s, 18H) 1.08 (t, 3H) 0.89 (t, 3H) 4 0-Propinoyl Clear liquid . . . . . . . . . 1735 (s), 5.47 (m, 1H) 5.3 (m, 1H) ricinoleic acid 1710 (s) 4.8 (p, 1H) 2.35 (t, 2H) 2.28 (q, 2H) 2.03 (m, 2H) 1.6 (m, 2H) 1.5 (br.m, 2H) 1.3 (br.d, 18H) 1.1 (t, 3H) 0.9 (t, 3H) 5 Sodium 0-butanoyl White solid 213 (dec.)1728 (s), 5.45 (m, 1H) 5.35 (m, 1H) ricinoleate 1562 (s) 4.8 (m. 1H), 2.3-2.0 (br.m, 4H) 1.7 (br.m, 4H) 1.5 (S, 18H) .098 (2t, 6H)

Entry substrates Physical M.P. ( C) IR (vc=0, 1H NMR Appearance in cm-1) 6 0-Butanoyl Clear liquid . . . . . . . . . 1735 (s), 5.49 (m, 1H) 5.43 (m, 1H) ricinoleic acid 1711 (s) 4.89 (p, 1H) 2.4-2.2 (m, 4H) 2.0 (br.q, 2H) 1.71.5 (m, 4H), 1.3 (s, 18H), 0.9 (t, 3H), 0.87 (t, 3H) 7 Sodium 0-heptanoyl White solid 217 (dec.) 1732 (m), ricinoleate 1553 (s) 8 0-Heptanoyl Clear liquid . . . . . . . . . 1737 (s) , 5.49 (m, 1H) 5.43 (m, 1H) ricinoleic acid 1711 (s) 4.88 (p, 1H) 2.4 (m, 6H) 2.03 (br.q, 2H), 1.66 (br.m, 6H), 1.26 (s,18H) 0.88 (br.s, 6H) 9 Sodium 0-dodecanoyl White solid 215 (dec.) 1734 (s), ricinoleate 1560 (s)

The products obtained were also subiected to Foam/ather test. The cylinder shake foam test was performed. Several soaD solutions were prepared !t w/v) and compared at different degree of hardness (French hardness). The results are shown in Table II below.

Table 2

Entry Substrates Ca+/0FH Initial Final (cm) (cm) 1 1 Sodium ricinoleate 0 0.1 0 (Control) 5 Nil 0 20 Nil 0 2 2 Sodium acetoxy 0 13.1 12 ricinoleate 5 9.7 5.1 20 10.5 0.6 3 Sodium Propioxy 0 16.5+1 14.5 ricinoleate 5 10.1+1 8.0 20 9.1 5.5 4 Sodium Butyroxy 0 14.2 11.5 ricinoleate 5 8.5 6.5 20 3.5 1.5 5 Sodium Heptanoyl 0 9.5 7.5 ricinoleate 5 8.5+1 7.5 20 5.0 3.5

Claims

CLAIMS 1. A Process for preparing a compound of formula :

wherein : M is selected from hydrogen, an alkali metal, ammonium and an alkylamine; and R is a linear or branched alkyl group containing 1 to 30 carbon atoms; the process comprising reacting ricinoleic acid with an acylating agent, wherein the mole ratio of ricinoleic acid to acylating agent is from 0.75:1 to 1.5:1, at a temperature within the range 0 to 350C.