ORGANIC SULFONIC ACID SALTS OF AMINO ACID ESTERS AND PROCESS FOR THEIR PREPARATION

Abstract

The application relates to a process for the synthesis of organic sulfonic acid salts of amino acid esters comprising the steps of (i) reacting at least one lactam with at least 3 carbon atoms in the lactam ring with at least one organic sulfonic acid in an aqueous solution, (ii) esterification of the organic sulfonic amino acid salt of step (i) with at least one alcohol with at least 8 carbon atoms comprising at least one hydroxyl group, (iii) optionally removal of water and/or removal of excess alcohol of step (ii). The application also relates to organic sulfonic acid salts of amino acid esters of the general formula (I).

##STR00001##

Claims

1. Process for the synthesis of organic sulfonic acid salts of amino acid esters comprising the steps of (i) reacting at least one lactam with at least 3 carbon atoms in the lactam ring with at least one organic sulfonic acid in an aqueous solution, (ii) esterification of the reaction product of step (i) with at least one alcohol with at least 8 carbon atoms comprising at least one hydroxyl group, (iii) optionally removal of water and/or removal of excess alcohol of step (ii).

2. Process according to claim 1, wherein step (i) and (ii) are carried out in one single step.

3. Process according to claim 1, wherein the molar ratio of organic sulfonic acid to lactam is in the range of from 90 to 200 mol-%.

4. Process according to claim 2, wherein the combined step (i) and (ii) comprises reacting a mixture of organic sulfonic acid, at least one lactam with at least 3 carbon atoms in the lactam ring and at least one linear or branched C.sub.8- to C.sub.36-alcohol comprising at least one hydroxyl group at a temperature of 80 to 200° C. for 1 to 30 h.

5. Process according to claim 1, wherein the molar ratio of organic sulfonic amino acid salt of step (i) to hydroxyl groups is in the range of from 50 to 125 mol-% in case a monoalcohol is used in step (ii).

6. Process according to claim 1, wherein the molar ratio of organic sulfonic amino acid salt of step (i) to hydroxyl groups is in the range of from 10 to 125 mol-% in case a di- or polyalcohol is used in step (ii).

7. Process according to claim 1, wherein the alcohol used in step (ii) is selected from the group consisting of mono-alcohols, diols, polyols, alkoxylated mono-alcohols, alkoxylated diols, and alkoxylated polyols.

8. Process according to claim 1, wherein the lactam used in step (i) is a ε-lactam.

9. Process according to claim 1, wherein the organic sulfonic acid is selected from the group consisting of dodecylbenzene sulfonic acid, p-toluene sulfonic acid, xylene sulfonic acid, and methanesulfonic acid.

10. Process according to claim 1, wherein the organic sulfonic acid is methanesulfonic acid

11. Organic sulfonic acid salt of an amino acid ester according to formula (I) ##STR00004## wherein R1 is a selected from the group consisting of methanediyl, ethanediyl, propanediyl, butanediyl, pentanediyl, hexanediyl, heptanediyl, octanediyl, nonanediyl, and decanediyl, wherein R2 is H or C.sub.1- to C.sub.12-alkyl, wherein R3 is a linear or branched, unmodified or modified with one or more hydroxy groups, alkyl with at least 8 carbon atoms, or a linear or branched, unmodified or modified with one or more hydroxy groups etheralkyl with at least 8 carbon atoms, wherein R4 is selected from the group consisting of C.sub.3-C.sub.30-alkyl group, phenyl group, phenoxyalkyl group, alkaryl group except toluyl group, C.sub.3-C.sub.30-alkenyl group with at least one double bond in the alkene chain camphor group, and mixtures thereof.

12. Organic sulfonic acid salts of amino acid esters according to claim 11, wherein R4 is a substituted phenyl group according to formula (II), ##STR00005## wherein the bond marked with * marks the bond connecting the group to the sulfur atom, and wherein R5, R6, R7, R8, and R9 are each independently selected from the group consisting of hydrogen, and linear and branched C.sub.1- to C.sub.20-alkyl groups, excluding the selection of one of R5 to R9 being methyl while the remaining groups are all hydrogen.

13. Organic sulfonic acid salts of amino acid esters according to claim 12, wherein one of R5, R6, R7, R8, and R9 is a linear or branched C.sub.11-alkyl group and the remaining substituent are hydrogen.

Description

EXAMPLES

Methods

[0057] .sup.1H NMR measured in MeOD with Bruker Avance 400 MHz spectrometer.

Example 1

[0058] In a 4-neck vessel with thermometer, reflux condenser, nitrogen inlet, dropping funnel, and stirrer, 141.45 g caprolactam (80 wt.-% aqueous solution) are placed and heated to 70° C. At this temperature 140.04 g methane sulfonic acid (70 wt.-% aqueous solution) are added within 20 minutes. Temperature is raised to 118° C. and the mixture is stirred for 3 hours. The mixture is cooled to 90° C. and 156.27 g 2-ethylhexanol are added within 20 minutes. The reaction mixture is heated to 120° C. and vacuum (950-850 mbar) is applied to remove the water. After 3 hours at 120° C. the vacuum is lowered to 20 mbar. The reaction mixture is stirred for 2.5 hours at 20 mbar and 130° C. 332.0 g of a light brown solid is obtained. .sup.1H-NMR in MeOD indicates complete conversion to 6-amino-hexane acid-2-ethylhexylester methane sulfonic acid salt.

Example 2

[0059] In a 4-neck vessel with thermometer, reflux condenser, nitrogen inlet, dropping funnel, and stirrer, 141.45 g caprolactam (80 wt.-% aqueous solution) and 156.27 g 2-ethylhexanol are placed and heated to 40° C. At this temperature 140.04 g methane sulfonic acid (70 wt.-% aqueous solution) are added within 20 minutes. Temperature is raised to 110° C. and the mixture is stirred for 3 hours at 110° C. Vacuum is applied and lowered to 20 mbar, simultaneously the temperature is raised to 140° C. The reaction mixture is stirred for 2.5 hours at 20 mbar and 140° C. 330.0 g of a light brown solid is obtained. .sup.1H-NMR in MeOD indicates complete conversion to 6-amino-hexane acid-2-ethylhexylester methane sulfonic acid salt.

Example 3

[0060] In a 4-neck vessel with thermometer, reflux condenser, nitrogen inlet, dropping funnel, and stirrer, 19.3 g caprolactam (80 wt.-% aqueous solution) and 38.7 g Cis/Cis fatty alcohol (hydroxyl value 217.4 mgKOH/g) are placed and heated to 70° C. At this temperature 27.3 g methane sulfonic acid (70 wt.-% aqueous solution) are added within 20 minutes. Temperature is raised to 120° C. and the homogeneous mixture is stirred for 3 hours at 120° C. Vacuum is applied and lowered to 20 mbar, simultaneously the temperature is raised to 138° C. The reaction mixture is stirred for 8 hours at 20 mbar and 140° C. 65.5 g of a light brown solid is obtained. .sup.1H-NMR in MeOD indicates complete conversion to 6-amino-hexane acid-Cis/Cis fatty alcohol ester methane sulfonic acid salt.

Example 4

[0061] In a 4-neck vessel with thermometer, reflux condenser, nitrogen inlet, dropping funnel, and stirrer, 19.3 g caprolactam (80 wt.-% aqueous solution) and 44.6 g Cis/C.sub.22 fatty alcohol (hydroxyl value 188.6 mgKOH/g) are placed and heated to 70° C. At this temperature 27.3 g methane sulfonic acid (70 wt.-% aqueous solution) are added within 20 minutes. Temperature is raised to 120° C. and the homogeneous mixture is stirred for 3 hours at 126° C. Vacuum is applied and lowered to 20 mbar, simultaneously the temperature is raised to 138° C. The reaction mixture is stirred for 8 hours at 20 mbar and 140° C. 71.4 g of a light brown solid is obtained. .sup.1H-NMR in MeOD indicates complete conversion to 6-amino-hexane acid-C.sub.18/C.sub.22 fatty alcohol ester methane sulfonic acid salt.

Example 5

[0062] In a 4-neck vessel with thermometer, reflux condenser, nitrogen inlet, dropping funnel, and stirrer, 21.3 g 2-pyrrolidon and 39.1 g 2-ethylhexanol are placed and heated to 50° C. At this temperature 35.0 g methane sulfonic acid (70 wt.-% aqueous solution) are added within 20 minutes. Temperature is raised to 104° C. and the mixture is stirred for 3 hours at 104° C.-110° C. Vacuum is applied and lowered to 20 mbar, simultaneously the temperature is raised to 135° C. The reaction mixture is stirred for 2.5 hours at 20 mbar and 135° C. 75.0 g of a light brown solid is obtained. .sup.1H-NMR in MeOD indicates complete conversion to 4-amino-butane acid-2-ethylhexylester methane sulfonic acid salt.

Example 6

[0063] In a 4-neck vessel with thermometer, reflux condenser, nitrogen inlet, dropping funnel, and stirrer, 24.7 g 2-piperidon and 39.6 g 2-ethylhexanol are placed and heated to 50° C. At this temperature 35.0 g methane sulfonic acid (70 wt.-% aqueous solution) are added within 20 minutes. Temperature is raised to 104° C. and the mixture is stirred for 5.5 hours at 104° C.-110° C. Vacuum is applied and lowered to 20 mbar, simultaneously the temperature is raised to 135° C. The reaction mixture is stirred for 2.5 hours at 20 mbar and 135° C. 81.0 g of a light brown solid is obtained. .sup.1H-NMR in MeOD indicates complete conversion to 4-amino-pentane acid-2-ethylhexylester methane sulfonic acid salt.

Example 7

[0064] In a 4-neck vessel with thermometer, reflux condenser, nitrogen inlet, dropping funnel, and stirrer, 35.4 g caprolactam (80 wt.-% aqueous solution) and 35.8 g 2-ethylhexanol are placed and heated to 45° C. At this temperature 48.5 g p-toluene sulfonic acid are added in portions within 20 minutes. Temperature is raised to 110° C. and the mixture is stirred for 4 hours at 110° C. Vacuum is applied and lowered to 20 mbar, simultaneously the temperature is raised to 140° C. The reaction mixture is stirred for 5 hours at 20 mbar and 140° C. 95.0 g of a light brown solid is obtained. .sup.1H-NMR in MeOD indicates 88% conversion to 6-amino-hexane acid-2-ethylhexylester p-toluene sulfonic acid salt.

Example 8

[0065] In a 4-neck vessel with thermometer, reflux condenser, nitrogen inlet, dropping funnel, and stirrer, 21.3 g caprolactam (80 wt.-% aqueous solution) and 43.6 g 2-Propylheptanol, ethoxylated with 3 mole ethyleneoxide are placed and heated to 45° C. At this temperature 52.6 g 4-dodecyl benzene sulfonic acid (mixture of isomers) are added within 20 minutes. Temperature is raised to 133° C. and the mixture is stirred for 4 hours at 133° C. Vacuum is applied and lowered to 5 mbar, simultaneously the temperature is raised to 140° C. The reaction mixture is stirred for 5 hours at 5 mbar and 140° C. 99.0 g of a brown oil is obtained. .sup.1H-NMR in MeOD indicates 82% conversion to 6-amino hexane acid acid-triethylene glycol 2-propyl-heptylether ester as 4-dodecylbenzene sulfonic acid (mixture of isomers) salt.

Example 9

[0066] In a 4-neck vessel with thermometer, reflux condenser, nitrogen inlet, dropping funnel, and stirrer, 21.2 g caprolactam (80% aqueous solution) and 26.1 g 2-propylheptanol are placed and heated to 40° C. At this temperature 52.6 g 4-dodecyl benzene sulfonic acid (mixture of isomers) are added within 20 minutes. Temperature is raised to 110° C. and the mixture is stirred for 4 hours at 110° C. The mixture is heated to 130° C. and formed water is distilled off for 5 hours. Vacuum is applied and lowered to 4 mbar, simultaneously the temperature is raised to 140° C. The reaction mixture is stirred for 4 hours at 4 mbar and 140° C. 77.0 g of a brown oil is obtained. 1H-NMR in MeOD indicates 81% conversion to 6-amino-hexane acid-2-propylheptylester 4-dodecyl benzene sulfonic acid (mixture of isomers) salt.

Example 10

[0067] In a 4-neck vessel with thermometer, reflux condenser, nitrogen inlet, dropping funnel, and stirrer, 21.2 g caprolactam (80 wt.-% aqueous solution) and 5.0 g water are placed and heated to 70° C. At this temperature 52.6 g 4-dodecyl benzene sulfonic acid (mixture of isomers) are added within 20 minutes. Temperature is raised to 118° C. and the mixture is stirred for 4 hours. The mixture is cooled to 90° C. and 21.5 g 2-ethylhexanol are added within 20 minutes. The reaction mixture is heated to 120° C. and vacuum (950-850 mbar) is applied to remove the water. After 3 hours at 120° C. the vacuum is lowered to 20 mbar. The reaction mixture is stirred for 2.5 hours at 20 mbar and 130° C. 77.4 g of a light brown oil is obtained. .sup.1H-NMR in MeOD indicates 73% conversion to 6-amino-hexane acid-2-ethylhexylester 4-dodecyl benzene sulfonic acid (mixture of isomers) salt.

Example 11

[0068] In a 4-neck vessel with thermometer, reflux condenser, nitrogen inlet, dropping funnel, and stirrer, 21.5 g 2-ethylhexanol and 19.7 g 6-amino hexane acid are placed and heated to 50° C. To the mixture 52.6 g 4-dodecyl benzene sulfonic acid (mixture of isomers) is added within 10 minutes. The reaction mixture is heated to 133° C. and is stirred for 4 hours at 133° C., formed water is distilled off. Excess 2-ethylhexanol and volatile compounds are removed in vacuo (7 mbar) at elevated temperature (140° C.) and 80.7 g of a light brown oil is obtained. .sup.1H-NMR in MeOD indicates complete conversion to 6-amino-hexane acid-2-ethylhexylester 4-dodecylbenzene sulfonic acid salt.

Example 12

[0069] In a 4-neck vessel with thermometer, reflux condenser, nitrogen inlet, dropping funnel, and stirrer, 43.6 g 2-Propylheptanol, ethoxylated with 3 mole ethylenoxide and 19.7 g 6-amino hexane acid are placed and heated to 90° C. To the mixture 52.6 g 4-dodecyl benzene sulfonic acid (mixture of isomers) is added within 10 minutes. The reaction mixture is heated to 135° C. and is stirred for 4 hours at 135° C. Vacuum (5 mbar) is applied and the reaction mixture is stirred for additional 10 hours at 140° C. 102.1 g of a light brown solid is obtained. .sup.1H-NMR in MeOD indicates complete conversion to 6-amino hexane acid acid-triethylene glycol 2-propyl-heptylether ester as 4-dodecylbenzene sulfonic acid (mixture of isomers) salt.

Example 13

[0070] In a 4-neck vessel with thermometer, reflux condenser, nitrogen inlet, dropping funnel, and stirrer, 42.4 g caprolactam (80% aqueous solution), 41.4 g phenoxyethanol and 18.5 g water are placed and heated to 40° C. At this temperature 99.9 g 4-dodecyl benzene sulfonic acid (mixture of isomers) are added within 10 minutes. The mixture is heated to reflux (approx. 100° C.) and stirred for 4 h under reflux. Vacuum is applied and lowered to 350 mbar, simultaneously the temperature is raised to 130° C. The reaction mixture is stirred for 5 hours at 350 mbar and 130° C. To remove residual water, the vacuum is lowered to 10 mbar, and the mixture is stirred for 2 h at 130° C. and 10 mbar. 160.0 g of a brown oil is obtained. .sup.1H-NMR in MeOD indicates 99.5% conversion to 6-amino hexane acid acid-phenoxyethanol-ester as 4-dodecylbenzene sulfonic acid (mixture of isomers) salt.

Example 14

[0071] In a 4-neck vessel with thermometer, reflux condenser, nitrogen inlet, dropping funnel, and stirrer, 62.2 g caprolactam (80% aqueous solution), and 67.5 g phenoxyethanol are placed and heated to 40° C. At this temperature 61.6 g methane sulfonic acid (70% aqueous solution) are added within 10 minutes. The mixture is heated to reflux (approx. 100° C.) and stirred for 4 h under reflux. Vacuum is applied and lowered stepwise to 10 mbar, simultaneously the temperature is raised to 130° C. The reaction mixture is stirred for 10 hours at 10 mbar and 130° C. 149.0 g of a brown solid is obtained. .sup.1H-NMR in MeOD indicates 97.2% conversion to 6-amino hexane acid acid-phenoxyethanol-ester as methane sulfonic acid salt.

Comparative Example 1

[0072] In a 4-neck vessel with thermometer, reflux condenser, nitrogen inlet, dropping funnel, and stirrer, 56.58 g caprolactam (80% in water) and 44.47 g i-butanol are placed and heated to 46° C. At this temperature 56.01 g methane sulfonic acid are added within 20 minutes. Temperature is allowed raised to 63° C. After complete addition of methane sulfonic acid, the temperature is raised to 104° C. (reflux), and the mixture is stirred for 11 hours at 105° C. Vacuum is applied and lowered to 20 mbar, to remove excess of i-butanol, and stirred for 1 hour. .sup.1H-NMR in MeOD indicates a 45:55 mixture of 6-amino-hexane acid-i-butanolester methane sulfonic acid salt and non-esterified 6-amino-hexane acid methane sulfonic acid salt.

Stability in Alkaline Solution

[0073] To determine the stability under alkaline conditions, 50 wt % of the organic sulfonic acid salt of an amino acid ester is dissolved in water, pH is adjusted with sodium hydroxide to pH 8.5. The aqueous solution or emulsion is stored for 7 days at room temperature and 40° C. Before storage the integral of CH2-O—CO— (.sup.1H-NMR in MeOD, ˜4.2 ppm) is measured. The stability of organic sulfonic acid salt of an amino acid ester is indicated by measuring the integral of CH2-O—CO— (.sup.1H-NMR in MeOD) after storage. The residual amount of ester bonds is calculated:

[00001]$\mathrm{Residual}.Math..Math.\mathrm{amount}.Math..Math.\mathrm{ester}.Math..Math.\mathrm{bond}.Math.\left[\%\right]=\frac{\begin{array}{c}\mathrm{integral}.Math..Math.\mathrm{CH}.Math..Math.2.Math.\mathrm{—O—CO—}\\ \mathrm{after}.Math..Math.\mathrm{storage}\end{array}}{\begin{array}{c}\mathrm{integral}.Math..Math.\mathrm{CH}.Math..Math.2.Math.\mathrm{—O—CO—}\\ \mathrm{before}.Math..Math.\mathrm{storage}\end{array}}\times 100$

TABLE-US-00001 TABLE 1 Residual amount of ester bonds after storage [%], calculated from .sup.1H-NMR in MeOD 7 d 7 d pH 8.5 pH 8.5 Reaction product of RT 40° C. Comparative 2-Ethylhexanol and Lysine, 59 15 example 2 methane sulfonic acid salt Comparative 2-Ethylhexanol + Glycine, 37 20 example 3 methane sulfonic acid salt Comparative 2-Ethylhexanol + Alanine, 72 46 example 4 methane sulfonic acid salt Comparative 2-Ethylhexanol + Alanine, 63 60 example 5 dodecylbenzene sulfonic acid salt Example 11 2-Ethylhexanol + 6-Aminohexane 100 100 acid, dodecylbenzene sulfonic acid salt *Comparative examples 2 to 5 were prepared analog to the procedure disclosed in Example 11.

Use as Additives in Detergents

[0074] Technical stain swatches of blue knitted cotton containing Bacon Grease were purchased from Warwick Equest Ltd. The stains were washed for 30 min in a launder-o-meter (manufactured by SDL Atlas) at room temperature using per canister 500 mL of washing solution, 20 metal balls and ballast fabrics. The washing solution contained 5000 ppm of detergent composition DC1 (table 2). Water hardness was 2.5 mM (Ca.sup.2+:Mg.sup.2+ was 4:1). Additives were added to the washing solution of each canister separately and in the amount as detailed below. After addition the pH value was re-adjusted to the pH value of washing solution without additive. Standard colorimetric measurement was used to obtain L*, a* and b* values for each stain before and after the washing. From L*, a* and b* values the stain level were calculated as color difference ΔE (calculated according to DIN EN ISO 11664-4) between stain and untreated fabric.

[0075] Stain removal from the swatches was calculated as follows:

[00002]$\mathrm{Stain}.Math..Math.\mathrm{Removal}.Math..Math.\mathrm{Index}.Math..Math.\left(S.Math..Math.R.Math..Math.I\right)=\frac{\Delta .Math..Math.E_{\mathrm{initial}}-\Delta .Math..Math.E_{\mathrm{washed}}}{\Delta .Math..Math.E_{\mathrm{initial}}}\times 100$

ΔE.sub.initial=Stain level before washing
ΔE.sub.washed=Stain level after washing

[0076] Stain level corresponds to the amount of grease on the fabric. The stain level of the fabric before the washing (ΔE.sub.initial) is high, in the washing process stains are removed and the stain level after washing is smaller (ΔE.sub.washed). The better the stains have been removed the lower the value for ΔE.sub.washed will be and the higher the difference will be to ΔE.sub.initial. Therefore, the value of stain removal index increases with better washing performance.

TABLE-US-00002 TABLE 2 Detergent composition DC1 Ingredients of liquid detergent percentage composition DC1 by weight n-C.sub.10-C.sub.13-alkylbenzene sulfonic acid 5.3 coconut C.sub.12-C.sub.18 fatty acid 2.4 sodium laureth sulfate + 2 EO 7.7 potassium hydroxide 2.2 C.sub.13C.sub.15- oxo alcohol + 7 EO 5.4 1,2 propylene glycol 6 ethanol 2 water pH of detergent To Balance composition DC1 = 8.0

TABLE-US-00003 TABLE 3 Washing Experiment SRI, Bacon Graese Cleaning Without additive 10.6 Product of example 7 (2-Ethylhexanol, 38.4 ester with 6-amino hexane acid, toluenesulfonic acid salt); 0.15 g per wash Product of example 8 (2-Propylheptanol, 31.5 ethoxylated with 3 mole ethylenoxide, ester with 6-amino hexane acid, 4-do- decylbenzene sulfonic acid (mixture of isomers) salt); 0.1825 g per wash Product of example 8 (2-Propylheptanol, 31.8 ethoxylated with 3 mole ethylenoxide, ester with 6-amino hexane acid, 4-do- decylbenzene sulfonic acid (mixture of isomers) salt); 0.2012 g per wash Product of example 10 (2-ethyl-hexanol, 50.4 ester with 6-amino hexane acid, 4-dodecylbenzene sulfonic acid (mixture of isomers) salt); 0.2546 g per wash