EP0958042A1

EP0958042A1 - Fluid concentrated hydroalcoholic compositions of copra or oil palm alkyl-amidopropylbetains

Info

Publication number: EP0958042A1
Application number: EP98952797A
Authority: EP
Inventors: Régine De Mesanstourne; Stéphane Fouquay; Jean-Paul Gamet; François GUILLEMET
Original assignee: Carbonisation et Charbons Actifs CECA SA
Current assignee: Carbonisation et Charbons Actifs CECA SA
Priority date: 1997-11-07
Filing date: 1998-10-27
Publication date: 1999-11-24
Also published as: JP2001507720A; NO313574B1; FR2770841A1; NO993334D0; NO993334L; WO1999024157A1; FR2770841B1; US6335370B1; AU1036899A

Abstract

The invention concerns fluid, stable and pumpable hydroalcoholic solutions of copra or oil palm alkyl-amidopropylbetains with betain content higher than 50 % occupying a well defined zone in their ternary diagram betain/water/ethanol. Said solutions are prepared by synthesis and quaternization of amidoamine directly in the solvent medium wherein they are defined.

Description

_CO MP _OS itions hydroalcoholic CONCENTRATED FLUIDS alkyl- AMID _O R _O PYLBETAÏNES coconut or palm kernel oil.

TECHNICAL FIELD OF THE INVENTION

The invention relates to concentrated hydroalcoholic solutions of low viscosity, clear, little colored and stable in a temperature range between 5 and 50 ° C, and containing at least 50% by weight of al-yl-amidopropyl-betaine corresponding to the general formula (I):

CH-

(I) wherein RI represents alkyl radical of a natural cut coconut type of fatty acid or palm kernel, which are approximately of saturated fatty acids, about 4 to ₀ -5 _0% lauric acid and 15-20% myristic acid (in the rest of the presentation, we simply say betaine). The solutions exhibit these qualities only if their composition is chosen precisely in a zone of the betaine / ethanol / water diagram normalized to 100 by weight after correction of the NaCl present.

The betaines corresponding to the general formula (I) are amphoteric surfactants very well tolerated by the skin, having excellent cleaning and foaming characteristics, and which are entirely suitable for making a multitude of surfactant compositions, such as washing agents, cleaning agents (liquid products for washing dishes by hand) and compositions for hair care (shampoos) and body care (shower gels and bubble baths).

OVERVIEW OF THE STATE OF THE ART

The preparation of this type of betaine is described in numerous documents, and the methods are known to those skilled in the art, for example the patent US 3,225,074 ⁽ American _C yanamid). It consists in reacting a fatty acid or a cutting fatty acids with N, N-dimethyl-1,3-propanediamine (DMAPA) between 140 and 200 ° C, then quaternizing the tertiary amidoamine obtained, of general formula (II):

CH-

R _χ —CONH— (CH ₂ ) ₃ —N ^{N (H} 3

(II) with monochloroacetic acid in the presence of an alkaline salt or the corresponding salt of this acid, the quaternization reaction most often taking place in an aqueous medium. The alkali chloride, frequently sodium chloride, a by-product of the reaction, is generally left in this aqueous betaine solution. These aqueous betaines are sold with a concentration close to 30% by weight. We have often tried to industrially prepare the most concentrated and most fluid betaine solutions possible, for understandable reasons of reducing transport and storage costs, without sacrificing the ease of their handling. Those skilled in the art know that when the concentration of an aqueous solution of surfactant increases, its viscosity also increases. Some authors have nevertheless sought to concentrate, by evaporation under reduced pressure, the betaine solutions obtained according to the usual methods, but their viscosity increases rapidly, and they become pasty to around 40% by weight of betaine, then continue to solidify as measurement of the water departure: it is not possible to obtain concentrated solutions along this route. It is however reported in EP 0,302,329 (Th. Goldschmidt) that it was possible to partially circumvent this difficulty by adjusting the pH of the solution between 1 and 4.5 with a mineral acid (hydrochloric, sulfuric, phosphoric). The authors thus obtain solutions containing 43 to 44% by weight of betaine (or 53 to 54% of dry extract) with a viscosity close to 1000 Pa.s at 25 ° C. However, the corrosion problems during storage and transport and the atypical pH of these betaine solutions limit their use, and moreover they gel below 16 ° C. Another route is that of obtaining powdered betaine, by atomization of the fluid solutions to less than 30%. We can think of redissolving these powders in suitable solvents, but the redissolution of these powders is hampered by the formation, when the powder and the solvent are brought into contact, of lumps or gelled pastes which can practically no longer pass into solution at least in reasonable time and compatible with an industrial activity.

International application WO 95/12856 (HENKEL) discloses and claims a process for manufacturing surfactants of betaine type with low salt content (0.98 to 1.01% residual NaCl) by quaternization of tertiary amines and / or tertiary amidoamines with sodium monochloroacetate in a hydroalcoholic mixture composed of 5 to 10% by weight of water and 35 to 50% by weight of ethanol and / or isopropanol, this reaction being followed by a elimination of the precipitated salt fraction, total elimination of the solvent and readjustment of the reaction medium in water in order to bring the solution to the desired concentration of active material, in this case 30%. The water / ethanol weight ratio claimed by the authors is typical of a process aimed at removing the NaCl formed during the reaction. A composition of this kind had been the subject of US patent 4,705,893 (KAO), represented by a pentagonal zone of the ternary betaine / water / ethanol diagram defined by the triangular coordinates (80/10/10), (80/15/5 ), (40/55/5), 40 / 27.5 / 32.5) and (52.5 / 10 / 37.5). In both cases, these are processes the essential objective of which is to obtain solutions of totally aqueous non-concentrated amphoteric surfactants with low salt contents. Those skilled in the art are familiar with the idea of the possible existence of fluid phase domains in an amphoteric / water / solvent surfactant system. This idea is taken up in WO 95/14076 (Albright and Wilson), in reality with no other concrete teaching than that of the individual examples reported in this publication which most closely approach the conditions of the present problem, namely coconut or lauryl compositions. amidopropylbetaine - salt in solution in a mixed solvent of water / glycol type. The problem which remains posed is that of obtaining solutions of alkylbetaine of copra or palm kernel which are as concentrated as possible, that is to say at least 50% by weight, clear and little colored, fluid and pumpable (viscosity less than 1000 mPa.s), stable between 5 and 50 ° C over extended periods of time, in order to reduce packaging, transport and storage costs, which are easy to handle and can be formulated in l 'state with other surfactants, for example alkyl ether sulfates, alkanolamides, or other basic raw materials used in particular in the formulations of liquid soaps, shampoos, shower gels, and other cosmetic preparations.

PRESENTATION OF THE INVENTION The present invention provides a solution to this technical problem, which consists in preparing alkylbetaine in the presence of small amounts of ethanol, provided however to be limited to a very precise and narrow domain of the phase diagram such that defined now. We reason in ternary compositions betaine / water / ethanol, represented on the ternary diagram in reduced coordinates

B * = [betaine / (betaine + water + ethanol)]. 10 ² W * = [water / (betaine + water + ethanol)]. 10 ² E * = [ethanol / (betaine + water + ethanol)]. 10 ² where betaine has the meaning of, and is measured as betaine = dry extract - NaCl, where the looping relationship at 100% of the composition B * + W * + E * = 100 applies, all the quantities betaine, dry extract, water, ethanol, ClNa being expressed by weight, the reduced quantities B *, W * and E *, appearing as% weights.

With this definition, the betaine taken into account is a crude betaine, that is to say made up of alkylamidobetaine as corresponding to formula I, with some reactive residues and some reaction by-products of not more than 3% by weight. (see example 1).

The compositions of the invention are those which obey relationships

55% <B * <62% E *> 21% 37% <W * / W * + E * <50%

In the compositions of the invention, NaCl is present at a maximum level of 4.5% by weight, a value beyond which these compositions become uncontrollable, if only by precipitation of the salt. The compositions according to the invention are suitable for prolonged storage over periods of at least three months, during which no gelling, no demixing, no precipitation of salts is observed, no significant change in color or clarity in the temperature range between 5 and 50 ° C. These solutions also have the advantage of being low foaming in the concentrated state which facilitates their handling. Another advantage is that these concentrated solutions are sufficiently resistant to microbial invasion, so that the addition of preservatives is unnecessary. These characteristics make these solutions particularly suitable for making cosmetic compositions.

Another object of the present invention relates to the process for the manufacture of these concentrated solutions which consists in preparing the dimethylaminopropylamides of coconut or palm kernel intermediates and in quaternizing them with monochloroacetic acid in the presence of sodium hydroxide or the sodium monochloracetate directly in the chosen solvent medium, that is to say obeying the rule of composition

E *> 21% 37% <W * / W * + E * <50% defined above.

EXAMPLES

The examples and counter-examples which follow will make the invention better understood. Example 1: manufacture of a copra betaine containing approximately 59.2% by weight of betaine, ie 63.3% of dry extract, the reduced coordinates B * / W * / E * in the phase diagram are 61 , 7 / 15.4 / 22.9 (in% by weight).

1 / a - Preparation of the coconut amidoamine (Mw = 208 g) Load 731 kg of coconut fatty acid melted at 50 ° C. into a reactor. Purge the reactor and its contents by bubbling with nitrogen and bring it to 190 ° C. Add 366 kg of dimethylaminopropylamine (DMAPA) in 4 hours by immersing, continuously removing the distillation water. Maintain at 190 ° C. under a stream of nitrogen until the reaction product displays an acid number of less than 4.5 mg KOH / g. Cool to 150 ° C, inject by immersion in 1 hour 100 kg of water and dry at 150 ° C with nitrogen bubbling to a water content of less than 0.1%. Cool to 60 ° C, stop nitrogen sparging and drain.

The usual characteristics of the tertiary amidoamine thus obtained are the following:

1 / b - Manufacture of the concentrated solution of coconut Betaine

In another reactor, load 197 kg of ethanol at room temperature, then 169 kg of monochloroacetic acid. Bring to 25 ° C, then slowly add 473 kg of the amidoamine prepared in 1 / a, controlling the exotherm so that the temperature does not exceed 40 ° C. Then add 159 kg of 50% sodium hydroxide in about one hour, keeping the temperature at 40 ° C, then slowly rise to 80 ° C. Maintain at this temperature until the amidoamine content reaches a stable value of 1% while ensuring that the pH of a test sample previously diluted to 5% in water is always between 10 - 10 , 5. After one hour, cool to 40 ° C and adjust the pH to 6.5 with a 31% HCl solution. Remove the precipitated NaCl fraction by decantation, filtration or centrifugation.

A concentrated betaine solution is thus obtained having the following main compositions:

at. : 20 minutes at 105 ° C h: Active ingredient betaine = dry extract - NaCl (including glycolate, free fatty acid and free amidoamine) _Q: Values B *, W * and E * in the ternary diagram, after correction of the content in NaCl then normalization to 100 by weight and the following additional characteristics: d: Rhéomat 180: Mobile 12; speed 231 (5 ° C) / 354

(23 ° C) / 1291 (45 ° C) e. : aging at 45 ° C

It is a fluid solution, clear and easy to pump, stable between 5 and 50 ° C.

Counterexample 1: The operating conditions of step l / b of Example 1 are repeated, with the exception of the raw material charges, which have been adjusted to obtain a copra betaine containing approximately 66.2% betaine. , is

68.7% of dry extract, whose triangular coordinates B * / W * / E * corrected for NaCl in the phase diagram are

67.8 / 14.1 / 18.1 (in% by weight).

A viscous non-Newtonian birefringent gel, of the liquid crystal type, is obtained which is difficult to handle and to formulate between 5 and 50 ° C.

Counterexample 2: The operating conditions of step l / b of Example 1 are repeated, with the exception of the raw material charges, which have been adjusted to obtain a copra betaine containing approximately 62.6% betaine. gross either

65.0% solids content, whose triangular coordinates B * / W * / E * corrected for NaCl in the phase diagram are

64.1 / 15.4 / 20.5 (in% by weight). A fluid, clear and monophasic solution is obtained near ambient temperature (20 - 25 ° C) but which, between 5 and 15 ° C, undergoes a rapid evolution towards a biphasic mixture with a viscous gel phase. birefringent and a supernatant liquid phase. This heterogeneous product is difficult to use in the state.

Counterexample 1: The same operating conditions are used as in step l / b of Example 1, with the exception of the raw material charges, which have been adjusted to obtain a copra betaine at approximately 57.5% of betaine, ie 61.6% of dry extract, whose triangular coordinates B * / W * / E * corrected for NaCl in the phase diagram are 60/25/15 (in% by weight).

A viscous non-tonic birefringent gel, of the liquid crystal type, is obtained which is difficult to handle and to formulate between 5 and 50 ° C.

Counterexample 4: The operating conditions of step l / b of Example 1 are repeated, with the exception of the raw material charges, which have been adjusted to obtain a copra betaine containing approximately 47.8% betaine. , ie 52.3% of dry extract, whose triangular coordinates B * / W * / E * corrected for NaCl in the phase diagram are 50/35/15 (in% by weight).

A viscous non-Newtonian birefringent gel, of the liquid crystal type, is obtained, difficult to handle and to formulate between 5 and 50 ° C.

Counterexample 5: The same operating conditions as in step l / b of Example 1 are repeated, with the exception of the raw material charges, which have been adjusted to obtain a copra betaine at approximately 58.2% of betaine, ie 60% of dry extract, whose triangular coordinates B * / W * / E * corrected for NaCl in the phase diagram are 58.5 / 13.5 / 28.0 (in% by weight).

A solution is obtained which becomes heterogeneous on storage at 5 ° C.

Claims

1. Compositions comprising an alkylamidopropyl betaine, salt, water and ethanol, being in the form of fluid solutions, easy to pump, clear and little colored, stable between 5 and 50 ° C and having a viscosity less than 1000 mPa.s, the alkyl radical of said alkylamidopropylbetaine being that of a natural cut of fatty acid of the coconut or palm kernel type, characterized in that the components betaine, water and ethanol, reported in compositions reduced by

B * = [betaine / (betaine + water + ethanol)]. 10 ² W * = [water / (betaine + water + ethanol)]. 10 ² E * = [ethanol / (betaine + water + ethanol)]. 10 ² where betaine has the meaning of, and is measured as betaine = dry extract - NaCl, are linked by the relationships 55% ≤ B * <62% E *> 21% 37% ≤ W * / W * + E * ≤ 50% which define their field of existence of the compositions as long as their salt content is less than 4.5% by weight.

2. Method for obtaining the compositions as described under claim 1, which consists in preparing dimethylaminopropylamides of coconut or palm kernel intermediates and in quaternizing them with monochloroacetic acid in the presence of sodium hydroxide or with sodium monochloroacetate directly in the solvent water / ethanol compound medium so that we have E *> 21%

37% <W * / W * + E * ≤ 50% the reduced compositions E * and W * having the meanings given in claim 1.