METHOD FOR PRODUCING CATIONIC SURFACTANT

Abstract

The present invention provides a method for producing a high quality cationic surfactant, which is prevented from smelling and coloring, and has favorable storage stability.

The production method includes the following step 1, step 2, step 3, and step 4: step 1: a step of obtaining an alkanolamine ester by reacting an alkanolamine with a fatty acid or a fatty acid alkyl ester without using hypophosphoric acid or a salt thereof; step 2: a step of obtaining a cationic surfactant by quaternizing the alkanolamine ester obtained in the step 1 with a dialkyl sulfate; step 3: a step of performing an oxidation treatment of the cationic surfactant obtained in the step 2; and step 4: a step of performing a reduction treatment of the cationic surfactant subjected to the oxidation treatment obtained in the step 3.

Claims

1. A method for producing a cationic surfactant comprising the following step 1, step 2, step 3, and step 4: step 1: a step of obtaining an alkanolamine ester by reacting an alkanolamine with a fatty acid or a fatty acid alkyl ester without using hypophosphoric acid or a salt thereof; step 2: a step of obtaining a cationic surfactant by quaternizing the alkanolamine ester obtained in the step 1 with a dialkyl sulfate; step 3: a step of performing an oxidation treatment of the cationic surfactant obtained in the step 2; and step 4: a step of performing a reduction treatment of the cationic surfactant subjected to the oxidation treatment obtained in the step 3.

2. The method for producing a cationic surfactant according to claim 1, wherein the oxidation treatment in the step 3 is a treatment in which the cationic surfactant and an oxidizing agent are mixed with each other, and the using amount of the oxidizing agent is 0.001 parts by mass or more and 1.0 parts by mass or less with respect to 100 parts by mass of the cationic surfactant obtained in the step 2.

3. The method for producing a cationic surfactant according to claim 2, wherein the oxidizing agent is one or more selected from chlorous acid, hypochlorous acid, and alkali metal salts thereof.

4. The method for producing a cationic surfactant according to claim 1, wherein the reduction treatment in the step 4 is a treatment in which the cationic surfactant and a reducing agent are mixed with each other, the reducing agent is hypophosphoric acid or an alkali metal salt thereof, and the using amount of the reducing agent is 0.001 parts by mass or more and 1.0 parts by mass or less with respect to 100 parts by mass of the cationic surfactant obtained in the step 2.

5. The method for producing a cationic surfactant according to claim 1, wherein the alkanolamine is a dialkanolamine or a trialkanolamine.

6. The method for producing a cationic surfactant according to claim 1, wherein the alkanolamine is methyldiethanolamine or triethanolamine.

7. The method for producing a cationic surfactant according to claim 1, wherein in the step 2, the quaternization reaction is performed in the absence of solvents.

8. The method for producing a cationic surfactant according to claim 1, wherein after completion of the quaternization in the step 2, a solvent addition step is performed before the step 3.

9. The method for producing a cationic surfactant according to claim 8, wherein the solvent is at least one organic solvent selected from alcohols having 2 or more and 3 or less carbon atoms and solvents represented by the following general formula (1):
R.sup.1—O-(AO).sub.n—R.sup.2  (1) wherein R.sup.1 and R.sup.2 are the same or different and each represent hydrogen, an alkyl group having 1 or more and 30 or less carbon atoms, an alkenyl group having 1 or more and 30 or less carbon atoms, or an acyl group having 1 or more and 30 or less carbon atoms; A represents an alkylene group having 2 or more and 4 or less carbon atoms, and n represents a number on average of 1 or more and 40 or less, and A's are all the same or some of them are different.

10. The method for producing a cationic surfactant according to claim 8, wherein the addition amount of the solvent in the cationic surfactant after adding the solvent is such that the sum of the addition amount thereof and the amount of the solvent used in the other steps is 5% by mass or more and 60% by mass or less.

11. The method for producing a cationic surfactant according to claim 2, wherein the oxidizing agent is used in the form of an aqueous solution.

12. The method for producing a cationic surfactant according to claim 1, wherein the temperature in the oxidation treatment is 30° C. or higher and 90° C. or lower.

13. The method for producing a cationic surfactant according to claim 4, wherein the reducing agent is used in the form of an aqueous solution.

14. The method for producing a cationic surfactant according to claim 1, wherein the temperature in the reduction treatment is 30° C. or higher and 90° C. or lower.

Description

EXAMPLES

[0105] The “%” in the examples is on a mass basis unless otherwise specified.

Example 1

[0106] As the step 1, in a 1 L reaction vessel, triethanolamine (1.0 mol, triethanolamine-S, manufactured by Nippon Shokubai Co., Ltd.), partially hydrogenated palm fatty acid (1.65 mol, Palmac 605T, manufactured by ACIDCHEM), and 0.28 g of BHT were placed, and the resulting mixture was purged with nitrogen. Then, while bubbling nitrogen, the internal pressure of the vessel was reduced at 170° C. from normal pressure (0.1 MPa) to 13.3 kPa over 1 hour, and then, an esterification reaction was performed for 7 hours, whereby 569 g of triethanolamine ester having an acid value of 2.0 mgKOH/g was obtained.

[0107] Subsequently, as the step 2, 512 g (0.9 mol) of the triethanolamine ester obtained in the step 1 and 0.7 g of BHT were mixed, and to the resulting mixture, 107.8 g (0.855 mol) of dimethyl sulfate was added dropwise over 2 hours at a temperature ranging from 45° C. to 65° C. in a nitrogen atmosphere at normal pressure (0.1 MPa). After performing aging at a temperature from 60° C. to 65° C. for 1.5 hours, 84.9 g of ethanol was added thereto so that the amount of the solvent in the final cationic surfactant became 12% by mass, followed by mixing at a temperature from 55° C. to 65° C. for 0.5 hours.

[0108] Further, as the step 3, 1.4 g of a 25% aqueous solution of sodium chlorite was added thereto, followed by mixing at a temperature from 55° C. to 65° C. for 0.5 hours, whereby an oxidation treatment was performed. Thereafter, as the step 4, 0.35 g of a 50% aqueous solution of hypophosphoric acid was added thereto, followed by mixing at a temperature from 55° C. to 65° C. for 0.5 hours, whereby a reduction treatment was performed, and thus, a cationic surfactant was obtained. Incidentally, in Table 1, the net contents (parts by mass) of the oxidizing agent and the reducing agent with respect to 100 parts by mass of the cationic surfactant are shown. With respect to the obtained cationic surfactant, the smell and color were evaluated by the following methods immediately after the cationic surfactant was produced and after the cationic surfactant was stored in a nitrogen atmosphere at 60° C. for 8 weeks. The results are shown in Table 1.

<Evaluation Sample for Smell and Evaluation Method>

[0109] Preparation was performed by placing 100 g of a 15% aqueous solution of the bulk substance in a 450 mL glass bottle. [0110] Sensory evaluation was performed by 5 professional panelists according to the following criteria, and an average of the scores given by the panelists was determined as an evaluation value (a passing evaluation value for smell is 3.5 or less).

[0111] 1: The sample has no offensive odor.

[0112] 2: The sample has almost no offensive odor (has a very slight offensive odor).

[0113] 3: The sample has a weak offensive odor.

[0114] 4: The sample has a distinct offensive odor.

[0115] 5: The sample has a strong offensive odor.

[0116] 6: The sample has a very strong offensive odor.

<Evaluation for Color>

[0117] The color was measured according to the Gardner color scale using OME 2000 manufactured by Nippon Denshoku Industries Co., Ltd.

Example 2

[0118] A cationic surfactant was obtained by performing a procedure in the same manner as in Example 1 except that the amount of the 25% aqueous solution of sodium chlorite in the step 3 was changed to 4.2 g, and the amount of the 50% aqueous solution of hypophosphoric acid in the step 4 was changed to 0.71 g. The results obtained by performing the same evaluation as in Example 1 for the obtained cationic surfactant are shown in Table 1.

Example 3

[0119] A cationic surfactant was obtained by performing a procedure in the same manner as in Example 1 except that the amount of the 25% aqueous solution of sodium chlorite in the step 3 was changed to 0.56 g, and the amount of the 50% aqueous solution of hypophosphoric acid in the step 4 was changed to 0.71 g. The results obtained by performing the same evaluation as in Example 1 for the obtained cationic surfactant are shown in Table 1.

Example 4

[0120] A cationic surfactant was obtained by performing a procedure in the same manner as in Example 1 except that the amount of the 50% aqueous solution of hypophosphoric acid in the step 4 was changed to 0.71 g. The results obtained by performing the same evaluation as in Example 1 for the obtained cationic surfactant are shown in Table 1.

Example 5

[0121] A cationic surfactant was obtained by performing a procedure in the same manner as in Example 1 except that the amount of the 50% aqueous solution of hypophosphoric acid in the step 4 was changed to 0.14 g. The results obtained by performing the same evaluation as in Example 1 for the obtained cationic surfactant are shown in Table 1.

Example 6

[0122] A procedure was performed under the same conditions as in Example 1 except that nitrogen was bubbled in the step 1 at a flow rate shown in Table 1, and the internal pressure of the vessel was reduced at 190° C. from normal pressure (0.1 MPa) to 13.3 kPa over 1 hour, and then, an esterification reaction was performed for 4 hours, whereby 569 g of triethanolamine ester having an acid value of 2.1 mgKOH/g was obtained.

[0123] Subsequently, as the step 2, a procedure was performed in the same manner as in Example 1 except that aging was performed for 2.5 hours after dropwise addition of dimethyl sulfate, whereby a cationic surfactant was obtained. The results obtained by performing the same evaluation as in Example 1 for the obtained cationic surfactant are shown in Table 1.

Example 7

[0124] A cationic surfactant was obtained by performing a procedure in the same manner as in Example 1 except that the oxidizing agent in the step 3 was changed to sodium hypochlorite. The results obtained by performing the same evaluation as in Example 1 for the obtained cationic surfactant are shown in Table 1.

Comparative Example 1

[0125] A cationic surfactant was obtained by performing a procedure in the same manner as in Example 1 except that the step 3 and the step 4 were not performed. The results obtained by performing the same evaluation as in Example 1 for the obtained cationic surfactant are shown in Table 1.

Comparative Example 2

[0126] A cationic surfactant was obtained by performing a procedure in the same manner as in Example 1 except that the step 4 was not performed. The results obtained by performing the same evaluation as in Example 1 for the obtained cationic surfactant are shown in Table 1.

Comparative Example 3

[0127] A cationic surfactant was obtained by performing a procedure in the same manner as in Example 1 except that the step 3 was not performed. The results obtained by performing the same evaluation as in Example 1 for the obtained cationic surfactant are shown in Table 1.

Comparative Example 4

[0128] A cationic surfactant was obtained by performing a procedure in the same manner as in Example 1 except that the order of the treatments in the step 3 and the step 4 performed in Example 1 was changed. The results obtained by performing the same evaluation as in Example 1 for the obtained cationic surfactant are shown in Table 1.

Comparative Example 5

[0129] A cationic surfactant was obtained by performing a procedure in the same manner as in Example 1 except that in the step 1, 0.57 g of a 50% aqueous solution of hypophosphoric acid (a net content of 0.05 parts by mass with respect to 100 parts by mass of triethanolamine ester) was added, and dehydration esterification was performed for 3 hours as the aging, whereby 569 g of triethanolamine ester having an acid value of 1.6 mgKOH/g was obtained. The results obtained by performing the same evaluation as in Example 1 for the obtained cationic surfactant are shown in Table 1.

TABLE-US-00001 TABLE 1 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Step 1 Hypophosphoric acid — The same as in Example 1 — [parts by mass]*.sup.1 Triethanolamine (g) 149 149 Fatty acid (g) 449 449 Fatty acid/ 1.65 1.65 triethanolamine [eq/eq] Reaction temperature 170 190 [° C.] Reaction pressure [kPa] 13.3 13.3 Reaction time [hr] 7 4 Carrier gas Nitrogen Nitrogen bubbling bubbling 50 mL/min 10 mL/min Step 2 Dimethyl sulfate [eq] 0.95 The same as in Example 1 0.95 Dimethyl sulfate supply 45-65 45-65 temperature (° C.) Dimethyl sulfate supply 2.0 2.0 time (° C.) Aging temperature [° C.] 60-65 60-65 Aging time [hr] 1.5 2.5 Step 3 Oxidation treatment NaClO.sub.2 NaClO.sub.2 NaClO.sub.2 NaClO.sub.2 NaClO.sub.2 NaClO.sub.2 0.05 parts 0.15 parts 0.02 parts 0.05 parts 0.05 parts 0.05 parts by mass by mass by mass by mass by mass by mass 55-65° C./ 55-65° C./ 55-65° C./ 55-65° C./ 55-65° C./ 55-65° C./ 0.5 h 0.5 h 0.5 h 0.5 h 0.5 h 0.5 h Step 4 Reduction treatment Hypophosphoric Hypophosphoric Hypo- Hypo- Hypo- Hypo- acid acid phosphoric phosphoric phosphoric phosphoric 0.025 0.05 acid acid acid acid parts parts 0.05 parts 0.05 parts 0.01 parts 0.025 parts by mass by mass by mass by mass by mass by mass 55-65° C./ 55-65° C./ 55-65° C./ 55-65° C./ 55-65° C./ 55-65° C./ 0.5 h 0.5 h 0.5 h 0.5 h 0.5 h 0.5 h Common to Atmospheric gas Nitrogen Nitrogen Nitrogen Nitrogen Nitrogen Nitrogen Steps 2 to 4 Evaluation Immediately Smell 1.0 1.2 1.2 1.0 1.0 1.2 of product after Color [G] 1 1 1 1 1 1 production After Smell 2.0 1.8 2.2 1.8 2.0 2.2 storage at Color [G] 2 2 2 2 3 2 60° C. for 8 weeks Comparative Comparative Comparative Comparative Comparative Example 7 Example 1 Example 2 Example 3 Example 4 Example 5 Step 1 Hypophosphoric acid The same The same as in Example 1 0.05 [parts by mass]*.sup.1 as in Triethanolamine (g) Example 1 149 Fatty acid (g) 449 Fatty acid/ 1.65 triethanolamine [eq/eq] Reaction temperature 170 [° C.] Reaction pressure [kPa] 13.3 Reaction time [hr] 3 Carrier gas Nitrogen bubbling 50 mL/min Step 2 Dimethyl sulfate [eq] The same The same as in Example 1 The same Dimethyl sulfate supply as in as in temperature (° C.) Example 1 Example 1 Dimethyl sulfate supply time (° C.) Aging temperature [° C.] Aging time [hr] Step 3 Oxidation treatment NaClO Non NaClO.sub.2 Non Hypophosphoric NaClO.sub.2 0.05 parts 0.05 parts acid 0.05 parts by mass by mass 0.025 parts by mass 55-65° C./ 55-65° C./ by mass 55-65° C./ 0.5 h 0.5 h 55-65° C./ 0.5 h 0.5 h Step 4 Reduction treatment Hypo- Non Non Hypo- NaClO.sub.2 Hypo- phosphoric phosphoric 0.05 phosphoric acid acid parts acid 0.025 parts 0.025 parts by mass 0.025 parts by mass by mass 55-65° C./ by Mass 55-65° C./0.5 h 55-65° C./0.5 h 0.5 h 55-65° C./ 0.5 h Common to Atmospheric gas Nitrogen Nitrogen Nitrogen Nitrogen Nitrogen Nitrogen Steps 2 to 4 Evaluation Immediately Smell 1.4 1.0 1.0 5.8 4.0 4.4 of product after Color [G] 1 1 1 1 1 1 production After Smell 2.4 3.8 3.0 6.0 5.0 5.4 storage at Color [G] 2.5 6 6 2.5 2 2.5 60° C. for 8 weeks *.sup.1parts by mass with respect to 100 parts by mass of the total amount of the alkanolamine, the fatty acid, and the fatty acid alkyl ester in Step 1