PROCESS FOR THE PRODUCTION OF ALUMINUM SALTS OF A FATTY ACID

Abstract

A process for the production of aluminum salts of a fatty acid, comprising the following steps: a) mixing a fatty acid and an aqueous solution of a strong base to prepare an aqueous base/fatty acid mixture, b) mixing said aqueous base/fatty acid mixture with an aluminum source to prepare an aqueous base/fatty acid/aluminum mixture, c) mixing said aqueous base/fatty acid/aluminum mixture with an acid, and d) separating the produced aluminum salts of the fatty acid.

Claims

1. A process for the production of aluminum salts of a fatty acid, comprising the following steps: a) mixing a fatty acid and an aqueous solution of a strong base to prepare an aqueous base/fatty acid mixture, b) mixing said aqueous base/fatty acid mixture with an aluminum source to prepare an aqueous base/fatty acid/aluminum mixture, c) mixing said aqueous base/fatty acid/aluminum mixture with an acid, and d) separating the produced aluminum salts of the fatty acid.

2. The process according to claim 1, wherein said aluminum salts of a fatty acid are mono-, di- or trifatty acid aluminum salts.

3. The process according to claim 1, wherein said fatty acid is a fatty acid having chain lengths of C6 to C28, or mixtures thereof, preferably stearic acid, palmitic acid, or a mixture of such fatty acids.

4. The process according to claim 1, wherein said fatty acid is stearic acid.

5. The process according to claim 1, wherein said strong base is an alkali hydroxide, preferably sodium hydroxide or potassium hydroxide, more preferably sodium hydroxide.

6. The process according to claim 1, wherein said aluminum source is an alkali aluminate or aluminum powder, preferably sodium aluminate or aluminum powder, more preferably sodium aluminate.

7. The process according to claim 1, wherein the acid used in step c) is an organic acid, an inorganic acid, or a mixture of both.

8. The process according to claim 7, wherein said organic acid is a monocarboxylic acid, preferably formic acid or acetic acid.

9. The process according to claim 7, wherein said inorganic acid is preferably phosphoric acid, hydrochloric acid, nitric acid, sulfuric acid, or any of their derivatives, more preferably phosphoric acid.

10. The process according to claim 1, wherein the separating of the produced aluminum salts of the fatty acid is effected by a physical separation method, preferably by filtration.

11. The process according to claim 1, wherein the fatty acid and the aqueous solution of a strong base are mixed with an aromatic carboxylic acid, preferably benzoic acid.

12. The process according to claim 1, wherein the pH value of said aqueous base/fatty acid mixture is within a range of from 7 to 12.

13. The process according to claim 1, wherein the pH value of said acidified aqueous base/fatty acid/aluminum mixture is within a range of from 3.5 to 7.

14. Aluminum salts of a fatty acid obtainable by a process comprising the following steps: a) mixing a fatty acid and an aqueous solution of a strong base to prepare an aqueous base/fatty acid mixture, b) mixing said aqueous base/fatty acid mixture with an aluminum source to prepare an aqueous base/fatty acid/aluminum mixture, c) mixing said aqueous base/fatty acid/aluminum mixture with an acid, and d) separating the produced aluminum salts of the fatty acid, wherein the aluminum salts of a fatty acid have a content of at most 1000 ppm chloride and 5000 ppm sulfate.

15. Aluminum salts of a fatty acid according to claim 14, wherein said fatty acid is stearic acid.

16. Aluminum salts of a fatty acid according to claim 14, wherein said strong base is an alkali hydroxide, preferably sodium hydroxide or potassium hydroxide, more preferably sodium hydroxide.

17. Aluminum salts of a fatty acid according to claim 14, wherein said aluminum source is an alkali aluminate or aluminum powder, preferably sodium aluminate or aluminum powder, more preferably sodium aluminate.

Description

EXAMPLE V: EXPERIMENTS FOR THE PREPARATION OF LOW CHLORIDE AND LOW SULFATE ALUMINUM FATTY ACID SALTS (COMPARATIVE EXAMPLES)

[0037] Aluminum stearate was obtained on an industrial scale by reacting stearic acid with aqueous sodium hydroxide solution, and precipitation with aluminum sulfate. It is a white solid that is insoluble and floating in water. After filtering off, the product has a high water content. The sulfur content was measured by X-ray fluorescence analysis. Because the molecular weight of sulfur is 32 g/mol and that of sulfate is 96 g/mol, the sulfate content is three times as high as the sulfur content. In addition, the water content of aluminum stearate must be taken into account. It is on the order of 70% by weight and was measured for each sample.

TABLE-US-00001 Sulfate content (calculated) Sample Treatment [ppm] Starting 19000 material Mix 1 3 washes for 900 s with 60 weight parts 17700 of town water, 60° C., 10 s pressing of the filter Mix 2 1 wash for 900 s with 60 weight parts of 17700 town water, 60° C., 10 s pressing of the filter Mix 3 1 wash for 900 s with 60 weight parts of 19100 town water, 20° C., 10 s pressing of the filter Mix 4 1 wash for 900 s with 60 weight parts of 15500 demineralized water, 20° C., 10 s pressing of the filter Mix 5 1 wash for 600 s with 100 weight parts 17100 of town water, 20° C., 10 s pressing of the filter Mix 6 1 wash for 600 s with 100 weight parts 18300 of town water, 20° C., without pressing of the filter Mix 7 1 wash for 600 s with 100 weight parts 18300 of town water, 20° C., without pressing of the filter Mix 8 1 wash for 600 s with 100 weight parts 19100 of town water, 20° C., 10 s pressing of the filter Mix 9 1 wash for 1200 s with 100 weight parts 19300 of town water, 20° C., 10 s pressing of the filter

[0038] A sufficient reduction of the sulfate content could not be achieved by washing under different conditions.

Example 1: Synthesis of an Aluminum Mono-Di-Stearate

[0039] In a beaker, 1.5 l of distilled water was charged, and heated at 80° C. Subsequently, 43 g of solid sodium hydroxide was dissolved in the water. It is slowly saponified by adding 270 g of liquid vegetable-based stearic acid (70° C.). The stearic acid has a content of 66% by weight stearic acid and 27% by weight palmitic acid. Subsequently, 64.5 g of sodium aluminate, which had previously been dissolved in 250 g of water, was slowly added. After a stirring time of 15 minutes, the solution is acidified to a pH value of about 5.5 using 210 g of 60% acetic acid. After another 10 minutes of stirring time, the product is filtered off through a suction filter, and washed several times with distilled water. Drying is effected in a drying cabinet at 80° C. to a water content of <1.5%. The product shows the following analytical data: [0040] Aluminum content: 5.6% by weight [0041] Free fatty acid: 1.6% by weight [0042] Sodium content: <10 ppm [0043] Water content: 0.7% by weight.

Example 2: Synthesis of an Aluminum Di-Tri-Stearate

[0044] In a beaker, 21 of distilled water was charged, and heated at 70-80° C. Subsequently, 31.6 g of solid sodium hydroxide was dissolved in the water. It is slowly saponified by adding 185 g of liquid tallow-based stearic acid (70° C.). Subsequently, 24.6 g of sodium aluminate, which had previously been dissolved in 180 g of water, was slowly added. After a stirring time of 15 minutes, the solution is acidified to a pH value of about 5.5 using 84 g of 60% acetic acid. After another 10 minutes of stirring time, the product is filtered off through a suction filter, and washed several times with distilled water. Drying is effected in a drying cabinet at 80° C. to a water content of <1.5%. The product shows the following analytical data: [0045] Aluminum content: 3.9% by weight [0046] Free fatty acid: 12.2% by weight [0047] Sodium content: <10 ppm [0048] Water content: 1.1% by weight.

Example 3: Synthesis of an Aluminum Tri-Stearate

[0049] In a beaker, 1.5 l of distilled water was charged, and heated at 70-80° C. Subsequently, 29.2 g of solid sodium hydroxide was dissolved in the water. It is slowly saponified by adding 194 g of liquid vegetable-based stearic acid (70° C.). The stearic acid has a content of 55% by weight stearic acid and 45% by weight palmitic acid. Subsequently, 21.2 g of sodium aluminate, which had previously been dissolved in 250 g of water, was slowly added. After a stirring time of 15 minutes, the solution is acidified to a pH value of about 5.5 using 73 g of 60% acetic acid. After another 10 minutes of stirring time, the product is filtered off through a suction filter, and washed several times with distilled water. Drying is effected in a drying cabinet at 80° C. to a water content of <1.5%. The product shows the following analytical data: [0050] Aluminum content: 3.4% by weight [0051] Free fatty acid: 18.3% by weight [0052] Sodium content: <10 ppm [0053] Water content: 0.8% by weight.

Example 4: Synthesis of an Aluminum Mono-Di-Stearate

[0054] In a beaker, 1.5 l of distilled water was charged, and heated at 80° C. Subsequently, 43 g of solid sodium hydroxide was dissolved in the water. It is slowly saponified by adding 270 g of liquid vegetable-based stearic acid (70° C.). The stearic acid has a content of 66% by weight stearic acid and 27% by weight palmitic acid. Subsequently, 64.5 g of sodium aluminate, which had previously been dissolved in 250 g of water, was slowly added. After a stirring time of 15 minutes, the solution is acidified to a pH value of about 5.5 using 82.3 g of 85% phosphoric acid. After another 10 minutes of stirring time, the product is filtered off through a suction filter, and washed several times with distilled water. Drying is effected in a drying cabinet at 80° C. to a water content of <1.5%. The product shows the following analytical data: [0055] Aluminum content: 5.2% by weight [0056] Free fatty acid: 2.2% by weight [0057] Sodium content: <10 ppm [0058] Water content: 1.2% by weight.

Example 5: Synthesis of an Aluminum Complex Soap

[0059] In a beaker, 1.5 l of distilled water was charged, and heated at 80° C. Subsequently, 43 g of solid sodium hydroxide was dissolved in the water. It is slowly saponified by adding 26.8 g of solid benzoic acid. This is followed by adding 210 g of liquid vegetable-based stearic acid. Subsequently, 64.5 g of sodium aluminate, which had previously been dissolved in 250 g of water, was slowly added. After a stirring time of 15 minutes, the solution is acidified to a pH value of about 5.5 using 210 g of 60% acetic acid. After another 10 minutes of stirring time, the product is filtered off through a suction filter, and washed several times with distilled water. Drying is effected in a drying cabinet at 80° C. to a water content of <1.5%. The product shows the following analytical data: [0060] Aluminum content: 5.3% by weight [0061] Free fatty acid: 3.2% by weight [0062] Sodium content: <10 ppm [0063] Water content: 1.2% by weight.