JPH04334353A - Production of tetramethyl ammonium bicarbonate aqueous solution - Google Patents

Abstract

PURPOSE:To simply produce the subject compound by a short process in a short time in a good productivity by reacting dimethyl carbonate with trimethyl amine in the presence of methanol, subsequently hydrolyzing the reaction product only with water and simultaneously removing the methanol. CONSTITUTION:Dimethyl carbonate is reacted with trimethyl amine in the presence of methanol. The produced tetramethyl ammonium methyl carbonate contained in the reaction mixture is subjected to a hydrolysis reaction only with water, preferably ultrapure water, and simultaneously to a removal of the methanol to rapidly produce an aqueous solution of the tetramethyl ammonium bicarbonate. Preferably, the reaction is performed with water in a molar ratio of 1:5-100 between the tetramethyl ammonium bicarbonate and the water at 0-120 deg.C under a pressure of 10-500mmHg. The method gives aqueous solution of tetramethyl ammonium bicarbonate reduced in the amount of the remaining methanol.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an aqueous solution of tetramethylammonium hydrogen carbonate.

0002

[Prior Art] Dimethyl carbonate and trimethylamine are reacted in the presence of methanol to obtain a reaction mixture containing tetramethylammonium methyl carbonate, which is demethanolized to obtain tetramethylammonium hydrogen carbonate, and the aqueous solution is electrolyzed. Therefore, a method for producing an aqueous solution of quaternary ammonium hydroxide is disclosed in, for example, JP-A-63-2408.
It is known as described in Japanese Patent No. 0. However, this method requires many reaction steps and is poor in productivity.

0003

OBJECTS OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the production of conventional tetramethylammonium hydrogen carbonate aqueous solutions. The present invention relates to a method in which an aqueous tetramethylammonium hydrogen carbonate solution can be produced with high productivity by simultaneously carrying out the following steps.

0004

[Means for Solving the Problems] The method for producing an aqueous solution of tetramethylammonium hydrogen carbonate according to the present invention involves reacting dimethyl carbonate and trimethylamine in the presence of methanol to obtain a reaction mixture containing tetramethylammonium methyl carbonate. , is characterized in that tetramethylammonium methyl carbonate is hydrolyzed and simultaneously demethanolized while adding water to the reaction mixture.

In the method of the present invention, tetramethylammonium methyl carbonate is produced by reacting dimethyl carbonate and trimethylamine in the presence of methanol. Trimethylamine is usually used in a molar ratio of 0.8 to 3 relative to dimethyl carbonate, and methanol as a reaction solvent is usually used in a weight ratio of 5 or less, preferably 0.5 to 3, relative to dimethyl carbonate. Used in the range of 2.0. The reaction is carried out under normal pressure or increased pressure, preferably in a closed system, at 60 to 180°C, preferably 80 to 150°C.
．． It is carried out for 5 to 10 hours, preferably 2 to 6 hours. The reaction method may be a batch method or a partially continuous method in which trimethylamine is continuously supplied into a methanol solution of dimethyl carbonate.

Next, according to the method of the present invention, while adding ultrapure water to the reaction mixture containing tetramethylammonium methyl carbonate obtained in this way, tetramethylammonium methyl carbonate is hydrolyzed and at the same time demethanol is removed. As a result, an aqueous tetramethylammonium hydrogen carbonate solution is immediately obtained. The amount of water added to the reaction mixture containing methyl tetramethylammonium carbonate ranges from 5 to 100 molar ratio, preferably from 10 to 50 molar ratio, relative to methyl tetramethylammonium carbonate over the entire reaction time. Thus, according to the present invention, unreacted dimethyl carbonate, trimethylamine, methanol and water are simultaneously distilled off while adding water to the reaction mixture containing tetramethylammonium methyl carbonate, and thus the tetramethylammonium methyl carbonate is removed. Hydrolysis and demethanolization are carried out simultaneously.

[0007] Here, the reaction temperature is 0 to 120°C, preferably 30 to 100°C, and the reaction pressure is 10 to 500°C.
mmHg, preferably in the range of 100 to 300 mmHg, and the reaction time is 10 minutes to 20 hours, preferably 3
It ranges from 0 minutes to 10 hours. The aqueous solution of tetramethylammonium hydrogencarbonate thus obtained is diluted to an appropriate concentration and electrolyzed according to a conventional method to obtain an aqueous quaternary ammonium hydroxide solution. The electrolysis of tetramethylammonium hydrogen carbonate is carried out using an electrolytic cell equipped with a cathode chamber and an anode chamber separated by a diaphragm. Electrolysis is carried out by applying a DC voltage at a current density of 5 to 30 A/dm2 while circulating an aqueous solution and an aqueous solution of about 5 to 30% tetramethylammonium hydrogen carbonate in the anode chamber. As electrolysis progresses, the anode chamber is replenished with tetramethylammonium hydrogen carbonate and the aqueous quaternary ammonium hydroxide solution in the cathode chamber is extracted, allowing continuous electrolysis.

[0008]

[Effects of the Invention] As described above, according to the method of the present invention,
After reacting dimethyl carbonate and trimethylamine in the presence of methanol to obtain a reaction mixture containing tetramethylammonium methyl carbonate, water is added to the reaction mixture to hydrolyze the tetramethylammonium methyl carbonate and simultaneously remove methanol. By this, the process can be shortened and simplified, tetramethylammonium hydrogencarbonate can be obtained in a short time with good productivity, and furthermore, an aqueous solution of tetramethylammonium hydrogencarbonate with a small amount of residual methanol can be obtained. .

[0009]

【Example】

Example 1 190 g (2.1 mol) of dimethyl carbonate, 124 g (2.1 mol) of trimethylamine, and 190 g of methanol were charged into a reactor and reacted at 125° C. for 3 hours. The composition of the obtained reaction product was 0.8% by weight of trimethylamine.
, dimethyl carbonate 1.3% by weight, methanol 37.8% by weight, and tetramethylammonium methyl carbonate 60.1% by weight (yield 96.6%).

To 22.5 parts by weight of this 60% methanol solution of tetramethylammonium methyl carbonate, 29.4 parts by weight of ultrapure water was added from the center of the 40-stage distillation column to a total of 371 parts by weight. While feeding at the same time, the bottom temperature is 90℃, the top temperature is 43.5℃, and the pressure is 300mmH.
67.2 parts by weight/hour from the top by continuous distillation at
144.4 parts/hour from the side, 15 from the bottom
A fraction was obtained at 9.5 parts by weight/hour.

The composition of the top fraction is trimethylamine 1
．． 9% by weight, dimethyl carbonate 3.1% by weight, methanol 9%
The composition of the side fraction is 4.9% by weight, 0.1% by weight of water,
The composition of the bottom fraction was 12.39% by weight of methanol and 87.57% by weight of water, and the composition of the bottom fraction was 54.8% by weight of tetramethylammonium hydrogen carbonate and 45.2% by weight of water. This aqueous tetramethylammonium hydrogen carbonate solution was diluted with ultrapure water to a concentration of 15% and subjected to electrolysis.

The electrolytic cell used was equipped with an anode made of platinum metal oxide-coated titanium, a cathode made of nickel, and a naphion membrane (manufactured by DuPont), and the above concentration of 15% was placed in the anode chamber of this electrolytic cell. A tetramethylammonium hydrogen carbonate aqueous solution was circulated for a residence time of 10 seconds, and a quaternary ammonium hydroxide aqueous solution with a concentration of 5% was circulated in the cathode chamber for a residence time of 1.
A voltage of 15% was applied between the cathode and anode while cycling for 8 seconds.
A DC voltage with a current density of 30 A/dm2 was applied, the anode chamber was replenished with an aqueous tetramethylammonium hydrogen carbonate solution, and the corresponding amount was extracted from the cathode chamber. 10
After an hour, an aqueous solution containing 193.8 hours of quaternary ammonium hydroxide was obtained. Example 2 A reaction product containing tetramethylammonium methyl carbonate was obtained in the same manner as in Example 1. 760g of ultrapure water in the reactor
At the same time, add methanol and water to 60℃/200℃.
The reactor was distilled off under mmHg conditions to simultaneously hydrolyze and remove methanol. After the reaction was completed, tetramethylammonium hydrogen carbonate with a concentration of 60% was quantitatively obtained from the reactor.

Claims (3)

[Claims] Claim 1: Reacting dimethyl carbonate and trimethylamine in the presence of methanol to obtain a reaction mixture containing tetramethylammonium methyl carbonate, and then hydrolyzing the tetramethylammonium methyl carbonate while adding water to the reaction mixture. A method for producing an aqueous tetramethylammonium hydrogen carbonate solution, which comprises removing methanol at the same time. 2. The method according to claim 1, wherein water is added to the reaction mixture in a molar ratio of 5 to 100 to tetramethylammonium methyl carbonate, and the tetramethylammonium methyl carbonate is hydrolyzed and simultaneously demethanolized. A method for producing an aqueous solution of tetramethylammonium hydrogen carbonate. [Claim 3] Hydrolyzing tetramethylammonium methyl carbonate under conditions of a temperature of 0 to 120°C and a pressure of 10 to 500 mmHg while adding water in a molar ratio of 5 to 100 to tetramethylammonium methyl carbonate to the reaction mixture. 2. The method for producing an aqueous tetramethylammonium hydrogen carbonate solution according to claim 1, wherein methanol is removed at the same time.