阅读说明：本技术 制备浅色二盐的方法 (Process for preparing light-coloured disalts ) 是由 C·布鲁恩 A·贝勒 R·埃斯库申 H-C·拉茨 T·赫芬纳 于 2018-05-22 设计创作，主要内容包括：本发明涉及一种制备浅色含水表面活性剂组合物的方法,所述组合物包含：相对于整个组合物为10-60重量％的一种或多种通式(I)的α-磺基脂肪酸二盐(A),R<Sup>1</Sup>CH(SO<Sub>3</Sub>M<Sup>1</Sup>)COOM<Sup>2</Sup>(I),其中基团R<Sup>1</Sup>为具有6-18个碳原子的直链或支化烷基或烯基,基团M<Sup>1</Sup>和M<Sup>2</Sup>彼此独立地选自H、Li、Na、K、Ca/2、Mg/2、铵和链烷醇胺；和水,其中所述方法的特征在于将通式(Ia)的脂肪酸R<Sup>2</Sup>CH<Sub>2</Sub>COOH(Ia),其中基团R<Sup>2</Sup>表示具有6-18个碳原子的直链或支化烷基或烯基,(i)用气态三氧化硫进行磺化,(ii)将所得的酸性磺化产物—任选在陈化后—中和,然后(iii)用过氧化氢对其进行漂白,其中漂白在高于7的pH下在80-95℃的温度范围内在相对于整个组合物为50-500ppm的稳定剂存在下进行,所述稳定剂选自氧化镁、镁盐、水玻璃、次氮基三乙酸、乙二胺四乙酸、葡糖酸及其盐。(The present invention relates to a process for preparing a light-colored aqueous surfactant composition comprising: 10-60% by weight, relative to the total composition, of one or more alpha-sulfofatty acid di-salts (A), R) of general formula (I) 1 CH(SO 3 M 1 )COOM 2 (I) Wherein the radical R 1 Is a linear or branched alkyl or alkenyl radical having 6 to 18 carbon atoms, the radical M 1 And M 2 Independently of one another, from H, Li, Na, K, Ca/2, Mg/2, ammonium and alkanolamines; and water, wherein the process is characterized in that a fatty acid R of the general formula (Ia) 2 CH 2 (COOH Ia) wherein the group R 2 Representing a linear or branched alkyl or alkenyl radical having 6 to 18 carbon atoms, (i) sulphonation with gaseous sulphur trioxide, (ii) neutralisation of the resulting acidic sulphonation product, optionally after ageing, and (iii) bleaching it with hydrogen peroxide, wherein the bleaching is carried out at a pH above 7 in the temperature range of 80 to 95 ℃ in the presence of 50 to 500ppm, relative to the total composition, of a stabiliser selected from the group consisting of magnesium oxide, magnesium salts, water glass, nitrilotriacetic acid, ethylenediaminetetraacetic acid, gluconic acid and salts thereof.)

1. A method of making a light-colored aqueous surfactant composition comprising:

10 to 60% by weight, based on the total composition, of one or more alpha-sulfofatty acid di-salts (A) of the general formula (I),

R¹CH(SO₃M¹)COOM²(I)

wherein the radical R¹Is a linear or branched alkyl or alkenyl radical having 6 to 18 carbon atoms, the radical M¹And M²Independently of one another, from H, Li, Na, K, Ca/2, Mg/2, ammonium and alkanolamines,

the amount of water is such that,

wherein the fatty acids of the general formula (Ia),

R²CH₂COOH (Ia)

wherein the radical R²Is a linear or branched alkyl or alkenyl group having 6 to 18 carbon atoms,

(i) the sulfonation is carried out by using gaseous sulfur trioxide,

(ii) the acidic sulfonation product, optionally after aging, is neutralized and, thereafter,

(iii) bleaching with hydrogen peroxide, wherein the bleaching is carried out at a pH above 7 in the temperature range of 80-95 ℃ in the presence of 50-500ppm based on the entire composition of a stabilizer selected from the group consisting of magnesium oxide, magnesium salts, water glass, nitrilotriacetic acid, ethylenediaminetetraacetic acid, gluconic acid and salts thereof.

2. A process according to claim 1, wherein the radical R in formula (I)¹Is a saturated, linear alkyl radical having from 10 to 16 carbon atoms, where, for the compound (A), the situation is based on the total amount of the compound (A), where the radical R¹The proportion of the compound (A) which is a decyl group or a dodecyl group is 90% by weight or more.

3. A process according to claim 1 or 2, wherein the group M¹And M²Is sodium.

4. A process according to any one of claims 1 to 3, wherein in the bleaching step (iii), magnesium oxide is used as a stabilizer.

5. The process as claimed in any of claims 1 to 4, wherein in the bleaching step (iii), the stabilizer is used in an amount of 200-400 ppm.

6. The process according to any one of claims 1 to 5, wherein in the bleaching step (iii), the temperature in the bleaching step (iii) is adjusted to 85 to 92 ℃.

7. The process according to any of claims 1 to 6, wherein in the bleaching step (iii), the pH is adjusted to a value of 10 to 11.5, in particular 10.2 to 10.7.

8. The process according to any of claims 1 to 6, wherein in the bleaching step (iii), the pH is adjusted to a value of from 10.2 to 10.7.

9. The process according to any of claims 1 to 8, wherein in the bleaching step (iii) the hydrogen peroxide is used in the form of an aqueous solution having a commercial concentration of 30 to 70% by weight, in particular 30 to 40% by weight.

10. A process according to any of claims 1 to 9, wherein in the bleaching step (iii), hydrogen peroxide is metered continuously into the initially charged surfactant composition below the liquid level.

11. A process according to claim 10, wherein in the bleaching step (iii), the rate of metering of hydrogen peroxide is selected such that the fixed peroxide concentration is set to below 3000 ppm.

12. The process as claimed in claim 10, wherein in the bleaching step (iii), the metering rate of hydrogen peroxide is selected such that the fixed peroxide concentration is set at 100-1000 ppm.

13. Use of a surfactant composition obtainable by the process of any of claims 1 to 12 in a cosmetic composition.

14. Use according to claim 13, wherein the cosmetic composition is in the form of a shampoo, shower gel, soap, synthetic detergent, washing cream, lotion, scrub formulation, foam bath, oil bath, shower, shaving foam, shaving lotion, shaving cream and dental care product.

15. Use of the surfactant composition obtainable by the process of any of claims 1 to 12 in detergent and cleaning compositions.

16. Use according to claim 15, wherein the detergent and cleaning compositions are compositions with low pH values for cleaning hard surfaces, such as bath and WC cleaners and the like, and for cleaning and/or fragrancing gels for sanitary installations.

Technical Field

The present invention relates to a process for preparing light-colored aqueous surfactant compositions having alpha-sulfofatty acid di-salt content.

Prior Art

Anionic surfactants are some of the most common surface-active compounds used for various purposes in the cosmetic field, in addition to detergents and cleaners. Conventional anionic surfactants used in particular in cosmetics are alkyl ether sulfates (alkyl polyether sulfates, fatty alcohol polyglycol ether sulfates, shortly referred to as ether sulfates). They are characterized by a high foaming capacity, a high cleaning capacity, a low sensitivity to hardness and oils and are widely used in the preparation of cosmetics such as shampoos, bubble baths or showers, and hand dishwashing detergents.

For many current applications, in addition to good interfacial activity, there are other requirements for anionic surfactants. In particular, high dermatological compatibility is required in cosmetics. In addition, good foaming capacity and a pleasant feel are often desired. Furthermore, there is a need for anionic surfactants that can be prepared at least in part from biological sources, in particular also from renewable raw materials. The surfactants meeting this requirement are preferably alpha-sulfofatty acid di-salts, which can be obtained, for example, by sulfonating fatty acids with gaseous sulfur trioxide and subsequent neutralization.

It has long been known from the literature to sulfonate saturated fatty acids to prepare alpha-sulfofatty acids. Sulfonation is typically carried out by reacting the fatty acid with gaseous sulfur trioxide. However, the products obtainable in this case are dark in color, and this form has only limited application.

Various patent documents relate to the optimization of the sulfonation conditions in order to reduce the formation of the initial color support as far as possible from the outset, for example by comparing DE 4224735 with the documents cited therein. However, the improvement of the initial color alone does not produce an acceptable product color. In this way, only more bleachable product is provided. However, post-treatment in the form of bleaching agents is always required.

It is known that the bleaching of sulfonated products of fatty acid esters can be carried out with hydrogen peroxide, wherein the bleaching is carried out completely or partially with acid crude sulfonic acids which have not yet been neutralized (for example in comparison with DE1179931, DE1234709, DE 3319591). However, applicants' studies have shown that this cannot be easily transferred to the bleaching of fatty acid sulfonated products, because gelling occurs when the unneutralized acidic sulfonated products of fatty acids are bleached.

Applicants' research also indicates that neutralization of aqueous slurries of fatty acid sulfonated products using hydrogen peroxide at pH values of 7 or less does not achieve acceptable product color. Acceptable product color requires the use of very large amounts of hydrogen peroxide, long processing times, and also requires complex process monitoring and control, especially to avoid the formation of uncontrollable foam, and also leads to undesirable dilution, i.e. water ingress.

Description of the invention

The object of the present invention is to provide a simple, reliable, reproducible and economically feasible process for the preparation of light-colored aqueous surfactant compositions comprising alpha-sulfofatty acid disalts, which is based on sulfonation of fatty acids with gaseous sulfur trioxide and subsequent neutralization and bleaching, but which solves the technical problems of hydrogen peroxide bleaching described above.

In the context of the present invention, the term "light-colored" is understood to mean that the aqueous surfactant composition, after dilution to a dry residue of 4% by weight, based on the total content of the diluted solution, has a hessian color value of 200 hessian or less, preferably 100 hessian or less. In this case, the color measurement was performed by diluting with a mixture of deionized water (95 wt%) and isopropyl alcohol (5 wt%). Color measurements are made in 11mm circular cuvettes in commercially available color measuring instruments (e.g., Lico 500 from Hach Lange GmbH).

The present invention relates to a process for preparing a light-colored aqueous surfactant composition comprising:

10 to 60% by weight, based on the total composition, of one or more alpha-sulfofatty acid di-salts (A) of the general formula (I),

R¹CH(SO₃M¹)COOM²(I)

wherein the radical R¹Is a linear or branched alkyl or alkenyl radical having 6 to 18 carbon atoms, the radical M¹And M²Independently of one another, from H, Li, Na, K, Ca/2, Mg/2, ammonium and alkanolamines,

the amount of water is such that,

wherein the process is characterized in that fatty acids of the general formula (Ia),

R²CH₂COOH (Ia)

wherein the radical R²Serving as a toolA linear or branched alkyl or alkenyl group having 6 to 18 carbon atoms,

(i) the sulfonation is carried out by using gaseous sulfur trioxide,

(ii) the acidic sulfonated product, optionally after aging, is neutralized and then

(iii) Bleaching with hydrogen peroxide, wherein the bleaching is carried out at a pH above 7 in the temperature range of 80-95 ℃ in the presence of 50-500ppm based on the entire composition of a stabilizer selected from the group consisting of magnesium oxide, magnesium salts, water glass, nitrilotriacetic acid, ethylenediaminetetraacetic acid, gluconic acid and salts thereof.

As mentioned above, the composition obtained by the process of the present invention comprises 10 to 60% by weight, based on the total composition, of one or more alpha-sulfofatty acid di-salts (a) of the general formula (I). In a preferred embodiment, the composition comprises from 30 to 40% by weight, based on the total composition, of one or more alpha-sulfofatty acid di-salts (a) of the general formula (I).

In formula (I), the group M¹And M²Sodium (Na) is preferred.

As detailed above, the process of the present invention requires first reacting the fatty acid with gaseous sulfur trioxide. In this case, the sulfur trioxide is preferably in an SO of 1.0:1.0 to 1.5:1.0₃The molar ratio of fatty acid is used. In this case, the fatty acid is introduced into the reactor at a storage temperature of 70-95 ℃. Preferably, the liquid vulcanizate obtained after sulfonation is kept and aged at this temperature for 5 to 20 minutes in a temperature-controlled after-reaction coil.

The crude product obtained in this way (i.e. the acidic sulfonated product) is then partially or completely neutralized, preferably completely, with aqueous NaOH.

For the subsequent bleaching with hydrogen peroxide, the conditions described above apply, i.e.

The pH value is higher than 7,

2. the temperature is 80-95 ℃,

3. the bleaching is carried out in the presence of 50-500ppm based on the total composition of a stabilizer selected from the group consisting of magnesium oxide, magnesium salts, water glass, nitrilotriacetic acid, ethylenediaminetetraacetic acid, gluconic acid and salts thereof.

Preferably, the aqueous surfactant composition to be bleached is first charged to a reactor, stirred and temperature controlled, and adjusted to the desired pH. Then, a stabilizer is first added to the aqueous surfactant composition, which stabilizer prevents sudden decomposition of hydrogen peroxide under the selected bleaching conditions, thus preventing uncontrolled foam formation and heat emission. The stabilizer is preferably used in an amount of 200-400ppm based on the entire composition.

The initial charge thus prepared is charged with hydrogen peroxide (H)₂O₂) And (6) processing. The hydrogen peroxide is preferably used here in the form of a commercially available aqueous solution having a concentration of 30 to 70% by weight, preferably 30 to 45% by weight. The metering of hydrogen peroxide into the initially charged surfactant composition is carried out continuously, preferably through a tube immersed below the liquid level. In particular, the metering rate is selected to set<A steady state peroxide concentration of 3000ppm, preferably 100 and 1000ppm, to ensure a constant bleaching process.

The bleaching is preferably carried out at a temperature of from 85 to 92 ℃. During bleaching, the pH of the aqueous solution is adjusted in particular to a value of 10 to 11.5, in particular 10.2 to 10.7. If the pH drops during bleaching, it is readjusted. The pH was adjusted with aqueous NaOH. In this case, the concentration of the NaOH solution used is at most 50% by weight, preferably at most 20% by weight.

Use of a composition

The invention further relates to the use of the surfactant compositions obtainable by the process according to the invention in cosmetic compositions and also in detergents and cleaning agents.

Particularly preferred here, in terms of cosmetics, are those which are present in particular in the form of shampoos, shower gels, soaps, synthetic detergents, washing creams, lotions, scrub preparations, foam baths, oil baths, showers, shaving foams, shaving lotions, shaving creams and dental care products (e.g. toothpaste, mouthwashes, etc.).

In the case of detergents, products for cleaning hard surfaces, such as bath and WC detergents and the like, with low pH, as well as cleaning and/or fragrance gels for sanitary applications are particularly preferred here.

Examples

Substances used

Starting materials used:

unbleached aqueous composition comprising a natural C-based_12/14Fatty acid (C)_12/14Industrial quality alpha-sulfo fatty acid disodium salt with the weight ratio of 70: 30); consists of the following components: water content 46.5% and dry residue 53.5% from alpha-sulfo fatty acids or (di) sodium salts, C_12/14Fatty acid or sodium salt and sodium sulfate in a ratio of about 8:1:1, at a pH of 5.1.

The colour of the composition can only be measured after a further 10-fold dilution (corresponding to 0.4 wt% dry residue) using the method described below, followed by 330 haas.

Measuring methods therefor

pH: the pH was measured directly in the formulation (i.e., aqueous surfactant composition) using a standard commercially available pH meter.

Color: the aqueous surfactant composition was diluted with a mixture of deionized water (95 wt%) and isopropanol (5 wt%) to a dry residue of 4% (based on the total content of the diluted solution). The color values of the solutions were determined in 11mm circular cuvettes obtained from a commercially available color measuring instrument (Lico 500) from Hach Lange GmbH. Color values are expressed in hardson units.

Peroxide concentration: the concentration of peroxide was determined by a semi-quantitative test strip (MQuant from Merck) and the aqueous dilution was adjusted to be within the measurement range of the test strip.

Results of bleaching experiments

The data in tables 1 and 2 are based in each case on an initial charge of 100 kg.

Table 1:

in example 1 of the present invention, the process conditions were chosen to ensure good controlled bleaching progression (see product colour reduction with treatment time, compare with table 2). After 18 hours, a very light-colored product (88 hasen) was obtained.

In comparative example 1, conditions obvious to the person skilled in the art from the prior art were selected. It shows that acceptable bleaching progress is not achieved in the pH range below 7, i.e. in the acidic pH range, even at higher steady state peroxide concentrations (see product colour reduction with treatment time, compare with table 2). After 30 hours, the product was still too dark in color. The experiment was then terminated due to the long treatment time. Furthermore, the resulting foam formation proves to be problematic.

Comparative example 2 shows that bleaching cannot be initiated at all in the alkaline pH range without the addition of a stabilizer. The peroxide metered in decomposes immediately, so that extremely severe foam is formed.

Table 2 below shows the product color measured as a function of time during bleaching. In example 1 and comparative example 1, the harsen values first mentioned in each case are values within a measurable range.

TABLE 2