Surfactants with tetrahydrofuranyl system

Abstract

The invention relates to surfactants of general formula (I) in which R.sup.1 and R.sup.2 represent independently of one another represent H and SO.sub.3.sup.−X+ with the proviso that at least one of R.sup.1 and R.sup.2 is not H, n and m represent independently from each other numbers from 0-21 under the proviso that 4<n+m<26, and X.sup.+ represents a charge-balancing anion. The surfactants can be incorporated into detergents or cleaning agents, have excellent technological application properties and can be produced based on renewable raw materials.

Claims

1. An anionic surfactant of the general formula (I), ##STR00004## in which R.sup.1 and R.sup.2 represent, independently of one another, H and SO.sub.3.sup.−X.sup.+, with the proviso that at least one of R.sup.1 and R.sup.2 is not H, n and m represent, independently of one another, numbers from 0 to 21, with the proviso that 4<n+m<26, and X.sup.+ represents a charge-balancing cation.

2. A method for preparing an anionic surfactant of the general formula (I), ##STR00005## in which R.sup.1 and R.sup.2 represent, independently of one another, H and SO.sub.3.sup.−X.sup.+, with the proviso that at least one of R.sup.1 and R.sup.2 is not H, n and m represent, independently of one another, numbers from 0 to 21, with the proviso that 4<n+m<26, and X.sup.+ represents a charge-balancing cation, by a) acid-induced separation of water from ribitol, arabitol, xylitol, or mixtures thereof, optionally b) introducing protective groups for the two vicinal alcohol functions in the tetrahydrofuran ring, c) reaction of the primary alcohol function in the side chain of the substituted tetrahydrofuran with an alkyl halide, c) removing the protective groups from the two vicinal alcohol functions in the tetrahydrofuran ring, if these were introduced in step b), and d) subsequent sulfation using a sulfating agent and optionally neutralization by subsequent reaction with X.sup.+OH.sup.−, X.sup.+HCO.sup.−3 or X.sup.+.sub.2CO.sup.2−.sub.3, in which X.sup.+ represents an alkali metal cation or a grouping N.sup.+R.sup.3R.sup.4R.sup.5, in which R.sup.3, R.sup.4 and R.sup.5 represent, independently of one another, hydrogen, an alkyl group having 1 to 6 carbon atoms, or a hydroxyalkyl group having 2 to 6 carbon atoms.

3. A washing or cleaning agent containing an anionic surfactant of the general formula (I), ##STR00006## in which R.sup.1 and R.sup.2 represent, independently of one another, H and SO.sub.3.sup.−X.sup.+, with the proviso that at least one of R.sup.1 and R.sup.2 is not H, n and m represent, independently of one another, numbers from 0 to 21, with the proviso that 4<n+m<26, and X.sup.+ represents a charge-balancing cation.

4. The agent according to claim 3, wherein the agent comprises 1 wt. % to 99 wt. % of the surfactant of general formula (I).

5. The agent according to claim 3, wherein the agent further comprises up to 99 wt. % of additional surfactant.

6. The agent according to claim 3, wherein the agent is particulate and comprises builders, or in that the agent is liquid and comprises 1 wt. % to 90 wt. % of water, water-miscible solvent or a mixture of water and water-miscible solvent.

7. The agent according to claim 3, wherein the agent is portioned ready for individual dosing in a chamber made of water-soluble material and comprises less than 15 wt. % of water.

8. The surfactant according to claim 1 wherein the compounds of general formula (I), n and m represent, independently of one another, numbers from 0 to 17, the sum of n and m satisfies the inequality 4<n+m<20 and/or n represents a number from 0 to 4 and m represents a number from 5 to 14.

9. The agent according to claim 4, wherein the agent comprises 3 wt. % to 65 wt. % of the surfactant of general formula (I).

10. The agent according to claim 5, wherein the agent further comprises 3 wt. % to 65 wt. % of additional surfactant.

11. The agent according to claim 6, wherein the agent comprises builders in an amount in the range of 1 wt. % to 60 wt. %, or in that the agent is liquid and comprises 10 wt. % to 85 wt. % of water, water-miscible solvent or a mixture of water and water-miscible solvent.

12. The agent according to claim 7, wherein the water-soluble chamber comprises a range of 1 wt. % to 12 wt. %, of water.

13. The surfactant according to claim 8, wherein the sum of n and m satisfies the inequality 6<n+m<18.

14. The method according to claim 2, wherein the compounds of general formula (I), n and m represent, independently of one another, numbers from 0 to 17, the sum of n and m satisfies the inequality 4<n+m<20, and/or n represents a number from 0 to 4 and m represents a number from 5 to 14.

15. The agent according to claim 3, wherein the compounds of general formula (I), n and m represent, independently of one another, numbers from 0 to 17, the sum of n and m satisfies the inequality 4<n+m<20, and/or n represents a number from 0 to 4 and m represents a number from 5 to 14.

Description

EXAMPLES

Example 1

Synthesis of Sodium 5-((Dodecyloxy)Methyl)-4-Hydroxytetrahydrofuran-3-Yl Sulfate

(1) A: Preparation of 2-(hydroxymethyl)tetrahydrofuran-3,4-diol

(2) 25.0 g (164.3 mmol) ribitol were mixed with 50 ml of 3 molar H.sub.2SO.sub.4. The reaction mixture was heated under reflux for 24 h. Subsequently, it was cooled in ice water and the sulfuric acid was neutralized by adding sodium hydroxide. The reaction mixture was concentrated under vacuum until a brown syrup and a beige precipitate were formed; the solid residue was filtered off by means of a yellow band filter and the filtration residue was washed several times with methanol heated to 50° C. 21.15 g (96% yield) of 2-(hydroxymethyl)tetrahydrofuran-3,4-diol as a brown syrup, which formed a beige solid after 24 hours, were obtained from the filtrate after removal of the solvent.

(3) .sup.1H-NMR [D.sub.2O]: δ=3.54 (dd, I=12.3, 5.1 Hz, 1 H); 3.73 (m, 3 H); 3.98 (m, 2 H); 4.17 (m, 1 H) ppm .sup.13C-NMR [D.sub.2O]: δ=61.23; 70.97; 71.50; 72.14; 81.44 ppm

(4) B: Preparation of 2,2-dimethyltetrahydrofuro[3,4-d][1,3]dioxol-4-yl) methanol

(5) 29.16 g (217.4 mmol) 2-(hydroxymethyl)tetrahydrofuran-3,4-diol were mixed with 300 ml of dry acetone (4.1 mol, 18.9 equivalents) and 300 μl H.sub.2SO.sub.4 (98%). The reaction mixture was heated under reflux while stirring for 8 h. Subsequently, the reaction mixture was cooled with ice water, mixed with NaHCO.sub.3 and stirred for 5 minutes. The NaHCO.sub.3 was filtered off and the filtrate was concentrated in a rotary evaporator until 33.89 g (90% yield) of 2,2-dimethyltetrahydrofuro[3,4-d][1,3]dioxol-4-yl)methanol was obtained as yellowish oil.

(6) .sup.1H-NMR [CDCl.sub.3]: δ=1.34 (m, 3 H); 1.51 (s, 3 H); 3.20 (w, 1 H); 3.61 (m, 2 H); 3.96 (d, 2 H); 4.10 (t, 1 H); 4.64 (d, 1 H); 4.81 (t, 1 H) ppm

(7) .sup.13C-NMR [CDCl.sub.3]: δ=25.00; 26.71; 61.82; 72.91; 81.08; 81.92; 84.97; 113.03 ppm

(8) C: Preparation of 4-((dodecyloxy)methyl)-2,2-dimethyltetrahydrofuro[3,4-d][1,3]dioxole

(9) 0.8625 g sodium hydride (35.9 mmol, 0.7 equivalents) was added gradually to a solution of 8.9479 g 2,2-dimethyltetrahydrofuro[3,4-d][1,3]dioxol-4-yl) methanol (51.4 mmol) in 50 ml dimethylformamide; it was stirred for 5 minutes until H.sub.2 formation was no longer evident. 18.5 ml 1-bromododecane (77.0 mmol, 1.5 equivalents) were added and the reaction mixture was stirred at 80° C. for 7 hours. Subsequently, 15 ml deionized water was added, extracted twice with 30 ml of diethyl ether in each case, and the combined organic phases each washed with 10 ml of saturated aqueous sodium bicarbonate, ammonium chloride and sodium chloride solution. After drying by means of sodium sulfate, the organic phase was concentrated in the rotary evaporator. The crude product was purified by column chromatography (petroleum ether:diethyl ether 9:1). This produced 7.0 g (40% yield) of 4-((dodecyloxy)methyl)-2,2-dimethyltetrahydrofuro[3,4-d][1,3]dioxole as a pale yellow liquid.

(10) .sup.1H-NMR [CDCl.sub.3]: δ=0.81 (t, 5 H); 1.19 (s, 21 H); 1.44 (s, 4 H); 3.33 (ddd, 2 H); 3.43 (dd, 2 H); 3.92 (m, 2 H); 4.08 (td, 1 H); 4.64 (dd, 1 H) ppm

(11) .sup.13C-NMR [CDCl.sub.3]: δ=14.12; 22.69; 24.98; 26.12; 26.66; 29.35; 29.43; 29.44; 29.54; 29.60; 29.62; 29.64; 29.67; 31.92; 71.80; 71.82; 74.26; 81.56; 82.81; 83.60; 112.41 ppm

(12) D: Preparation of 2-((dodecyloxy)methyl)tetrahydrofuran-3,4-diol

(13) 40 ml of an aqueous 80 wt. % acetic acid solution was added to 6.8989 g 4-((dodecyloxy)methyl)-2,2-dimethyltetrahydrofuro[3,4-d][1,3]dioxole (20.14 mmol). The reaction mixture was heated to 80° C. and stirred for 7 hours. Subsequently, the reaction mixture was cooled to room temperature using ice water. 20 ml deionized water was added and the product was extracted with diethyl ether (2×40 ml). The combined organic phases were washed 3 times with 15 ml deionized water, 15 ml saturated aqueous NaHCO.sub.3 solution and 15 ml saturated aqueous NaCl solution. After drying by means of sodium sulfate, the purified organic phase was concentrated in the rotary evaporator. This produced 5.30 g (87% yield) 2-((dodecyloxy)methyl)tetrahydrofuran-3,4-diol as a white solid.

(14) .sup.13C-NMR [CDCl.sub.3]: δ=14.10; 22.68; 26.06; 29.32; 29.35; 29.48; 29.57; 29.60; 29.63; 29.67; 31.89; 31.91; 71.07; 71.31; 72.04; 73.16; 73.29; 81.13 ppm

(15) E: Preparation of sodium 5-((dodecyloxy)methyl)-4-hydroxytetrahydrofuran-3-yl sulfate

(16) A solution of 3.17 g (7.83 mmol) 2-((dodecyloxy)methyl)tetrahydrofuran-3,4-diol in 200 ml acetonitrile was mixed gradually with 4.755 g (15.72 mmol, 1.5 equivalents) sulfur trioxide pyridine complex. Subsequently, the reaction mixture was heated to 75° C. for 6 hours. 0.13 ml deionized water was then added and the solvent was removed in the rotary evaporator. The yellow-brown syrupy residue was absorbed in 200 ml of ethanol, mixed with 2.00 g NaHCO.sub.3 (23.80 mmol, 1.5 equivalents) and stirred at room temperature overnight. The mixture was then filtered off by means of silica gel and washed twice with 100 ml ethanol and twice with 200 ml methanol. The combined filtrates were concentrated in the rotary evaporator. This produced 4.20 g (99% yield) sodium 5-((dodecyloxy)methyl)-4-hydroxytetrahydrofuran-3-yl-sulfate (P1) as a white powder.

(17) .sup.13C-NMR [CDCl.sub.3]: δ=14.44; 2.74; 27.21; 30.49; 30.75; 30.09; 48.68; 48.86; 49.08; 49.29; 49.50; 71.69; 71.89; 71.99; 76.62; 77.29; 78.41; 79.17; 81.24; 81.99 ppm

(18) The critical micelle concentration (CMC) of surfactant P1 was determined by measuring the surface tension of its aqueous solution as a function of concentration at 25° C. and a pH of 8.5 to 0.1 g/l. The interfacial tension of an aqueous solution of P1 (concentration 1 g/l) with respect to isopropyl myristate at pH 8.5 and 25° C. was measured using the spinning drop method. After 20 minutes, a value of 5 mN/m was produced.

Example 2

Synthesis of Sodium 5-((Tetradecyloxy)Methyl)-4-Hydroxytetrahydrofuran-3-Yl Sulfate

(19) The process described in Example 1 was repeated, although the 1-bromododecane was replaced with 1-bromotetradecane in step C, or the following took place instead of steps B to D:

(20) A solution of 32.49 g (24.23 mmol) 3,4-dihydroxy-2-hydroxymethyl-tetrahydrofuran in 60 ml of dimethylformamide was mixed with 5.23 g sodium hydride (22.74 mmol; 0.7 equivalents) and stirred for 5 minutes until H.sub.2 formation was no longer evident. 72.60 ml 1-bromotetradecane (26.65 mmol, 1.1 equivalents) were added and the reaction mixture was stirred at 90° C. for 24 h. Subsequently, the reaction mixture was mixed with 30 ml deionized water and extracted twice with 40 ml diethyl ether each time. The combined organic phases were washed with 20 ml deionized water and 15 ml saturated sodium chloride solution and the solvent was removed in the rotary evaporator. The residue was absorbed in 200 ml petroleum ether, heated to 60° C. to complete dissolution with stirring, and then the solution was stored overnight at −18° C. The precipitate formed was filtered off and dried under high vacuum. This produced 15.39 g (20% yield) 2-((tetradecyloxy)methyl)tetrahydrofuran-3,4-diol as a white crystalline solid.

(21) .sup.13C-NMR [CDCl.sub.3]: 14.56; 23.81; 27.26; 30.56; 30.69; 30.74; 30.80; 30.82; 30.84; 30.87; 30.89; 33.15; 70.54; 72.71; 74.42; 78.20; 78.20; 78.49; 80.89 ppm

(22) Analogously to step E in Example 1, the thus obtained 2-((tetradecyloxy)methyl)tetrahydrofuran-3,4-diol was reacted with sulfur trioxide pyridine to form sodium-5-((tetradecyloxy)methyl)-4-hydroxytetrahydrofuran-3-yl sulfate (P2).