JP2002226438A - Method for producing highly pure quaternary ammonium carboxylate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a high pure inexpensive quaternary ammonium carboxylate. SOLUTION: This method for producing a quaternary ammonium carboxylate represented by the general formula: [R1R2R3R4N].R5-COO (R1 to R4 are each a 1 to 8C alkyl; R1 to R4 may be same or different each other; R5 is H or a 1 to 6C alkyl), comprising reacting a tertiary amine with a carboxylate in a polar solvent, is characterized by adding an organic alkali and water to the reaction solution and then thermally treating the mixture to decompose and remove an amide compound contained as an impurity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a quaternary ammonium carboxylate, and more particularly to a method for producing a high-purity quaternary ammonium carboxylate containing no amide compound as an impurity.

[0002]

2. Description of the Related Art Quaternary ammonium carboxylate is used as a raw material for surfactants, pharmaceuticals, cosmetics and the like. A quaternary ammonium hydroxide produced using a quaternary ammonium carboxylate as a raw material is used as a developing solution or a cleaning solution in the production of LSI devices as a strong alkali substance containing no metal.

As a method for producing a quaternary ammonium carboxylate, there is a method of reacting a quaternary ammonium hydroxide with a carboxylic acid, but the method is practical because of the complicated process and high cost. Is not a good way. An industrially practical method includes a method of adding a small amount of water in a polar solvent to react a tertiary amine with a carboxylic acid ester (JP-A-6-329603). For example, when a hydroxide is produced from a quaternary ammonium carboxylate, the quaternary ammonium carboxylate is often used as an aqueous solution. In this case, after the quaternization step, the solvent is removed / replaced by a distillation operation or the like. And provided as an aqueous solution.

In the method of reacting a tertiary amine with a carboxylic acid ester, a carboxylic acid ester reacts with a primary amine or a secondary amine contained in a trace amount in the raw material tertiary amine to produce an amide compound. When a surfactant or a cosmetic is manufactured using a quaternary ammonium carboxylate containing an amide compound as a raw material, a side reaction occurs and impurities are generated, or the amide compound is included as an impurity in the product to cause a deterioration in quality. The same quality deterioration occurs when a quaternary ammonium hydroxide is produced by electrolysis using a quaternary ammonium carboxylate containing such an amide compound as an intermediate. Since the amide compound in question is chemically relatively stable and has a high boiling point, it has been difficult to efficiently remove the amide compound by a distillation operation or the like during the production process of the quaternary ammonium carboxylate aqueous solution.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned various problems and to provide a method for producing a high-purity and inexpensive quaternary ammonium carboxylate.

[0006]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, reacted a tertiary amine with a carboxylic acid ester in a polar solvent to obtain a compound represented by the general formula
[R ₁ R ₂ R ₃ R ₄ N] · R ₅ —COO (R _{1 to} R ₄ have 1 carbon atom
To 8 alkyl groups. R _{1 to} R ₄ may be the same or different. R ₅ represents hydrogen or an alkyl group having 1 to 6 carbon atoms. In the method for producing a quaternary ammonium carboxylate represented by the formula (1), an amide compound contained as an impurity can be decomposed and removed by performing a heat treatment after adding an organic alkali and water to the obtained reaction solution. This led to the present invention.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

In the amide compound decomposition treatment of the present invention, an organic alkali and water are added to the reaction solution after the quaternization step, and the heat treatment is performed. The organic alkali used in the present invention hydrolyzes an amide compound into an amine and a carboxylic acid by acting as a base in heat treatment. The organic alkali to be used is required to have a chemical property that is not easily volatilized or decomposed in the amide compound decomposition step in addition to high basicity. Although the metal-based alkali is effective in decomposing the amide compound, it is difficult to remove the alkali metal from the product after decomposing the amide compound, and it is not suitable because it is finally mixed into the product to cause a deterioration in quality.

Examples of the organic alkali used in the present invention include a cyclic base containing at least one selected from primary, secondary and tertiary amines, nitrogen, oxygen and sulfur atoms, and quaternary ammonium hydroxide. And quaternary ammonium compounds such as quaternary ammonium carbonate and quaternary ammonium hydrogencarbonate, and these compounds may be used in combination of one or more kinds. Of these, the basicity is high, the amide compound is excellent in decomposability, and the volatility is low.
Quaternary ammonium hydroxide, quaternary ammonium carbonate,
Quaternary ammonium bicarbonate and the like are preferred. Furthermore, quaternary ammonium hydroxides having very strong basicity can be used particularly preferably. Specific examples of these compounds include tetramethyl ammonium hydroxide (TMAH),
Trimethylethylammonium hydroxide, triethylmethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, trimethyl (2-hydroxyethyl) ammonium hydroxide, triethyl (2-hydroxyethyl) ammonium hydroxide And hydroxides such as tripropyl (2-hydroxyethyl) ammonium hydroxide, and carbonates and bicarbonates thereof. These compounds may be used alone or in combination of two or more. More preferably, since there is little effect on the purity of the product, the general formula [R ₁ R ₂ R ₃ R ₄ N] (R _{1 to} R ₄ represents an alkyl group having 1 to 8 carbon atoms. R _{1 to} R ₄ May be the same or different.)
And at least one compound selected from quaternary ammonium hydroxides, quaternary ammonium carbonates, and quaternary ammonium hydrogencarbonates composed of the same ammonium ion as the quaternary ammonium carboxylate to be produced Is particularly preferred.

[0010] Even lower amines, such as tributylamine and tripropylamine having low volatility, alkanolamines such as monoethanolamine, diethanolamine and triethanolamine, aromatic amines, pyridine And the like. These compounds may be used alone or in combination of two or more.

The liquid property for decomposing the amide compound with practical efficiency in the decomposing step of the amide compound is alkaline. The appropriate value of the pH is selected in consideration of the content of the impurity amide compound, the decomposition treatment time, or the influence of the subsequent step, but is preferably pH 8 or more, more preferably pH 10 or more.

[0012] The organic alkali used should be adjusted to the optimum pH
The amount of the quaternary ammonium carboxylate is usually 0.01 to 100% by weight, preferably 0.1 to 100% by weight, based on the amount of the organic alkali. It is from 0.5 to 50% by weight, more preferably from 0.1 to 20% by weight. Organic alkali amount is 0.01
If the amount is less than 10% by weight, the pH of the reaction solution does not reach 8 or more, and the decomposition rate of the amide compound is reduced. If the amount is more than 100% by weight, the heating efficiency and productivity are remarkably reduced.
Among the organic alkalis shown in the present invention, quaternary ammonium hydroxides are particularly preferable because they have a remarkable basicity and can obtain a high ability to decompose amide compounds with a very small amount.

Depending on the type of the quaternary ammonium carboxylate to be produced, the starting carboxylic acid ester remains in the reaction solution as an unreacted component in the quaternization step and reacts with the organic alkali added during the amide compound decomposition treatment to form an alkali component. Consume. In some cases, a large amount of organic alkali must be added to obtain a sufficient amide compound decomposing ability. In such a case, the organic alkali and water are not immediately added to the reaction solution after the completion of the quaternization step. And water may be added to perform the amide decomposition treatment. The preheating temperature varies depending on the carboxylic acid ester, but is generally preferably from 40 to 150 ° C, more preferably from 80 to 120 ° C. The preheating time is 10 to 120 minutes, preferably 20 to 90 minutes. Further, nitrogen aeration may be performed in the preheating.

The amount of water added to the amide compound decomposing step is appropriately selected depending on the amount of the impurity amide compound and the organic alkali used. % Or more, preferably 1%
% By weight, more preferably 3% by weight or more. When the amount of water is lower than 0.5% by weight, the effect of the organic alkali acting as a base is reduced, and the decomposition rate of the amide compound is undesirably reduced.

The liquid temperature in the amide compound decomposition operation varies depending on the quaternary ammonium carboxylate to be produced.
To 150 ° C, more preferably 80 to 120 ° C
It is. When the liquid temperature is lower than 40 ° C., the hydrolysis of the amide compound becomes insufficient, and when the liquid temperature is higher than 150 ° C., the quaternary ammonium carboxylate to be produced may be decomposed or the cost may be increased in terms of the heat retention and material of the apparatus, which is preferable. Absent.

In the case of producing a quaternary ammonium carboxylate aqueous solution, the amide compound decomposition treatment may be performed in a solvent replacement step performed after the quaternization step. In the solvent replacement step, the reaction solvent is removed from the reaction solution containing the quaternary ammonium carboxylate and the reaction solvent and replaced with an aqueous solvent to obtain an aqueous quaternary ammonium carboxylate solution. The solvent replacement operation is preferably a continuous or batch distillation operation in terms of operability and economy. The liquid temperature during the solvent replacement operation varies depending on the type of the reaction solvent and the quaternary ammonium carboxylate to be produced, but is 40 to 1
The temperature is preferably 50 ° C, more preferably 80 to 120 ° C. When the liquid temperature is lower than 40 ° C., the hydrolysis of the amide compound becomes insufficient, and when the liquid temperature is higher than 150 ° C., the quaternary ammonium carboxylate to be produced may be decomposed or the cost may be increased in terms of the heat retention and material of the apparatus, which is preferable. Absent. The pressure for the solvent replacement operation may be normal pressure or reduced pressure.

When the amide compound contained in the quaternary ammonium carboxylate is decomposed and removed according to the present invention, the liquid obtained thereafter becomes highly alkaline. If the alkalinity of the liquid causes adverse effects such as damage to the equipment in the next step, a substance that neutralizes alkali is added to the reaction solution after the amide compound decomposition step to adjust the pH of the reaction solution. It may be adjusted. In this case, as a substance to be added, an organic acid such as a carboxylic acid, a quaternary ammonium hydrogencarbonate, or the like can be used.

In the step of decomposing and removing the amide compound according to the present invention, the reaction solution is treated as alkaline, so that the atmosphere is desirably an inert gas such as nitrogen so as not to absorb carbon dioxide in the air.

[0019]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples. Note that the present invention is not limited to these examples.

Examples 1 to 5 209 g of trimethylamine containing 700 ppm by weight of dimethylamine as impurities, 255 g of methyl formate, and 6 parts of water
g and a solvent (methanol) 565 g were charged into an autoclave, and the reaction temperature was 130 ° C. and the reaction pressure was 1.1 MPaG.
For 8 hours. 230 weight p after reaction
1028 g of a 38.9% by weight methanolic solution of tetramethylammonium formate containing pm of dimethylformamide (hereinafter DMF) and traces of trimethylamine, methyl formate and 6 g of water were obtained.

50 g of the obtained methanol solution of tetramethylammonium formate was heated at 70 ° C. for 30 minutes under a stream of nitrogen. Thereafter, the organic alkali and water shown in Table 1 were added, and DMF decomposition treatment was performed at 100 ° C. for 4 hours, and the DMF concentration in the liquid after the treatment was measured by gas chromatography. Table 1 shows the results. The values of the organic alkali and water shown in the table indicate the ratio to the charged tetramethylammonium formate by weight%. As shown in Table 1, as a result of performing heat treatment by adding an organic alkali and water, it was found that DMF in tetramethylammonium formate was removed to an extremely low concentration.

[0022]

[Table 1] *: Weight% of quaternary ammonium carboxylate in solution

Examples 6 to 10 273 g of triethylamine containing 500 ppm by weight of diethylamine as impurities, 211 g of methyl formate, and 5 parts of water
g, and 432 g of a solvent (methanol) were charged into an autoclave, and the reaction temperature was 140 ° C. and the reaction pressure was 1.5 MPaG.
For 10 hours. After the reaction, 220 wt ppm of an impurity diethylformamide (hereinafter referred to as DEF),
And traces of triethylamine, methyl formate, and 5 g
915 g of a 43.7% by weight solution of triethylmethylammonium formate in methanol containing water were obtained.

50 g of the obtained methanol solution of triethylmethylammonium formate was heated at 70 ° C.
Heated for 0 minutes. Thereafter, an organic alkali and water shown in Table 2 were added, and DEF decomposition treatment was performed at 100 ° C. for 4 hours. Table 2 shows the results of measuring the DEF concentration in the liquid after the treatment.
As shown in the table, as a result of performing a heat treatment by adding an organic alkali and water, D in the triethylmethylammonium formate was determined.
EF was found to be removed to very low concentrations.

[0025]

[Table 2] *: Weight% of quaternary ammonium carboxylate in solution

Examples 11 to 15 230 ppm by weight of impurity DM synthesized in Examples 1 to 6
50 g of a 38.1% by weight methanol solution of tetramethylammonium formate containing F and trace amounts of trimethylamine, methyl formate, and water were heated at 70 ° C. for 30 minutes under a stream of nitrogen. Thereafter, 100 g of water and an organic alkali were added, and batch simple distillation was performed at 100 ° C. for 4 hours under normal pressure to obtain a 50% by weight aqueous solution of tetramethylammonium formate.
Table 3 shows the result of measuring the concentration of DMF in the solution.
As shown in the table, as a result of performing heat treatment by adding an organic alkali and water, it was found that DMF in the aqueous solution of tetramethylammonium formate was removed to an extremely low concentration.
In addition, 10 g of a 50% by weight aqueous solution of tetramethylammonium hydrogencarbonate at room temperature for pH adjustment was added to 50 g of the aqueous solution of tetramethylammonium formate after the DMF decomposition treatment with tetramethylammonium hydroxide in Example 11. Was added. The pH of the aqueous solution containing tetramethylammonium formate dropped from 14 to 12.

Comparative Example A solvent replacement operation was performed in the same manner as in Examples 11 to 15 except that no organic alkali was added to 50 g of the methanol solution of tetramethylammonium formate obtained in Examples 1 to 6. The concentration of DMF in a weight% aqueous solution of tetramethylammonium formate was measured (Table 3). DMF
Was detected at a high concentration and remained in the product with almost no decomposition.

[0028]

[Table 3] *: Weight% of quaternary ammonium carboxylate in solution

[0029]

According to the method for producing a quaternary ammonium carboxylate of the present invention, an amide compound mixed as an impurity in the quaternization step can be efficiently decomposed and removed to a low concentration to obtain a highly pure quaternary ammonium carboxylate. It becomes possible to produce a quaternary ammonium carboxylate.

Claims (4)

[Claims] A tertiary amine is reacted with a carboxylic acid ester in a polar solvent to obtain a compound of the general formula [R ₁ R ₂ R ₃ R ₄ N] · R ₅ -CO
O (R _{1 to} R ₄ represent an alkyl group having 1 to 8 carbon atoms; R ₁
To R ₄ may be the same or different. R ₅ represents hydrogen or an alkyl group having 1 to 6 carbon atoms. The method for producing a quaternary ammonium carboxylate represented by the formula (1) is characterized in that an organic alkali and water are added to the reaction solution, followed by heat treatment to decompose and remove the amide compound. Method for producing acid salt. 2. The method according to claim 1, wherein the organic alkali is at least one selected from quaternary ammonium hydroxides, quaternary ammonium carbonates and quaternary ammonium hydrogencarbonates. Method. 3. The process for producing a high-purity quaternary ammonium carboxylate according to claim 1, wherein the pH of the reaction solution obtained by adding an organic alkali and water to the reaction solution and performing heat treatment is 8 or more. 4. The method for producing a high-purity quaternary ammonium carboxylate according to claim 1, wherein the heat treatment is batch or continuous distillation.