JPS62238232A - Production of carboxylic acid from aqueous solution of ammonium carboxylate - Google Patents

Abstract

PURPOSE:To obtain a carboxylic acid, by adsorbing ammonium cation from an aqueous solution of an ammonium carboxylate with a cation exchange resin and recovering the adsorbed ammonium cation as ammonia with an organic solvent. CONSTITUTION:A carboxylic acid and ammonia are separated from an aqueous solution of ammonium carboxylate (e.g. ammonium acrylate, ammonium succinate, etc.) by adsorbing ammonium cation with a cation exchange resin (especially preferably weakly acidic cation exchange resin) and desorbing and recovering ammonium cation as ammonia using an organic solvent (e.g. methyl alcohol, dimethyl sulfoxide, etc.) capable of giving ammonia by desorbing ammonium cation adsorbed to a resin. The carboxylic acid can be recovered in the form of an aqueous solution. EFFECT:The decomposition of ammonium carboxylate can be carried out at a low temperature to improve the recovery of the carboxylic acid.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for recovering ammonia from an aqueous ammonium carboxylate solution and producing carboxylic acid ftM. Among carboxylic acids, acrylic acid and methacrylic acid in particular are useful not only as raw materials for the synthesis of methyl acrylate and methyl methacrylate, but also as raw materials for various higher esters. Additionally, the dicarboxylic acids uccinic acid and adipic acid are also useful as raw materials for polymers.

(Prior art) Conventionally, as a method for recovering carboxylic acid from an aqueous ammonium carboxylate solution, there is a method of adding a nearly stoichiometric amount of strong acid gold and isolating the carboxylic acid. However, not only ammonium salts are generated and the processing costs are high, but also ammonia cannot be recovered at the same time, which poses problems.

Mayu thermally decomposes carboxylic acid ammonium salt.

There is also a method of completely isolating the carboxylic acid by liberating ammonia, but since this method is generally carried out at high temperatures, side reactions occur and by-products such as amides and nitriles are likely to be produced. Furthermore, carboxylic acid ammonium salts containing double-bonded gold have the disadvantage that a single polymerization reaction occurs.

As a countermeasure to this problem, British Patent No. 967552 proposes that a small amount of water gold be added to an incurable ammonium salt of carboxylic acid and heated under total reflux at a temperature above aoC in an organic solvent such as gold or hydrocarbon. By removing ammonia and unsaturated carboxylic acid? There are 4 ways to do it. However, when this method is applied to an aqueous ammonium carboxylate solution, the water bath solution must be dried or
Mayu must be concentrated, and the organic solvent is used under total reflux, which increases energy costs.

Furthermore, in Japanese Patent Publication No. 61-2055, an ammonium salt aqueous solution VC of acrylic acid or methacrylic acid, water and 6
A method has been reported in which acrylic acid or methacrylic acid is obtained by adding an inert organic solvent azeotropically at a temperature of 0 to 100 C (Z), performing azeotropic distillation, and distilling off water and free ammonia. hru.

However, even in this method, various inert organic solvents must be distilled azeotropically with water, resulting in high energy costs.

(Problem that the invention seeks to solve) British Percentage No. 967352 and Special Publication 1986-20
None of the methods in No. 55 use strong acids at all, so they are noteworthy in that they do not generate waste acids or ammonium salts of strong acids. However, this method was not industrially satisfactory due to the high energy cost.

(Means for Solving the Problems) The present inventors set the goal of solving these problems as follows:
Carboxylic acid′ is preferably prepared from an aqueous solution of ammonium carboxylate.
As a result of seven intensive studies on methods for producing fc, we found that a method of obtaining gold carboxylate while recovering all ammonia from an aqueous ammonium carboxylate solution using a cation exchange resin and an organic solvent 'Jt' was found to be extremely effective. Heading 1 The present invention was completed 1-.

That is, the present invention provides a method for separating carboxylic acid and ammonia from an ammonium carboxylic acid aqueous solution by adsorbing ammonium cations onto a cation exchange resin. This is a method for producing carboxylic acid from an aqueous solution of ammonium carboxylate, which involves desorbing and recovering ammonium cations adsorbed on a resin as ammonia using an organic solvent.

(0 As the ammonium carboxylate used in the present invention, any ammonium carboxylate that is soluble in water can be used.

However, when considering the adsorption equilibrium of ammonium cations to cation exchange resins, the acid dissociation constant (Ka) of the carboxylic acid constituting ammonium carboxylate in a water bath solution (25C) ranges from 10''-1 to 1O-1 ( pKa
Those in the range of 5 to 7 are suitable. For example, ammonium salicylate, ammonium benzoate,
Ammonium normal and isobutyrate, ammonium normal and isovalerate, ammonium acrylate, ammonium methacrylate, ammonium succinate, ammonium malonate, ammonium acyhinate, and the like can be used. The higher the concentration of the ammonium carboxylic acid aqueous solution, the higher the concentration of the obtained calphone (1 g).
degree. Also.

When handling aqueous solutions of ammonium carboxylates with double-bonded gold, such as ammonium acrylate and ammonium methacrylate, it is recommended to add common polymerization inhibitors such as kengoshasuikome, hydroquinone, and methoxyhydroquinone. b0 The amount of polymerization inhibitor added is determined by the operating temperature, operating time, etc. 1 Usually 0
．． Addition of 0.01 to 0.5 weight may be sufficient.

Q) The cation exchange resin to be used must be able to absorb all ammonium cations.

Even if the resin is out of alignment, the removal of ammonia from the resin using the bathing medium is considered to be 7'21. In case 1, a weakly acidic cation exchange resin is desirable, preferably a carboxylic acid-based resin with a functional group having a pKa value (25c) in the range of 4 to 5, and acrylic acid-based and methacrylic acid-based resins are particularly preferred. Are suitable.

■The organic solvent used to remove the ammonium cation adsorbed to the resin as ammonia may be any organic solvent as long as it does not react with ammonia.
Considering the diffusion into the resin containing water, a hydrophilic organic solvent is preferable.

Specific examples include alcohol #A such as methyl alcohol, ethyl alcohol, normal and ingrohanol, ketone a such as acetone and methyl ethyl ketone, cyclic ethers such as tetrahydrofuran and 1,4-dioxane, acetonitrile, acrylonitrile, etc. Nitriles, esters such as methyl acetate and ethyl acetate, and dimethyl sulfoxide.

Dimethylformamide, dimethylacetamide.

Pyrolidones are applicable.

■The operating temperature ranges from OC to 150C, considering the adsorption rate of ammonium cations to the cation exchange resin, the desorption rate of adsorbed ammonium cations as ammonia, the heat resistance temperature of the resin, the coagulation temperature of the aqueous solution, etc. Applicable. However, taking into account the diffusion rate of the solution into the resin and the life of the resin, a temperature range of 15C to ID0C is preferred, and preferably a temperature range of 15C to 70C during adsorption of ammonium cations.

1 from 5F3G when ammonia is desorbed using an organic solvent.
A warm thigh range of 00c is preferable. Regarding the operating pressure, it is possible to carry out under reduced pressure, normal FJE, or pressurized conditions, but if the vapor pressure of the organic solvent used is low, use a pressurized system to prevent boiling. It is desirable to implement this, and the equipment to be used may be a fluidized bed type equipment, a fixed bed type equipment, or a continuous ion exchange type equipment, but from a practical standpoint, it is preferable to use a Fixed bed systems with good contact efficiency and continuous ion exchange systems are suitable.

In this way, by applying an aqueous solution of ammonium carboxylate to the 14 ion exchange resin and first adsorbing the ammonium cation gold to the resin phase, the separation of ammonia and carboxylic acid is achieved! II. An aqueous solution of carboxylic acid is obtained. Next, after washing the cation exchange resin with the ammonium cations adsorbed with water, photons are applied to the organic solvent (hereinafter referred to as the desorption solvent), and the adsorbed ammonium cations are desorbed from the resin as ammonia, releasing ammonia. A solution containing the desorption solvent is obtained. By distilling this solution, all ammonia can be recovered.

On the other hand, the obtained friend carboxylic acid is resistant to water.

If an oil agent that has a low degree of mutual bathing with water and a boiling point higher than that of the target carboxylic acid is brought into contact with the liquid, the carboxylic acid is extracted, and then distilled, the t-carboxylic acid can be obtained by condensation. .

(Function and Effect) In the method for recovering all ammonia from an aqueous ammonium carboxylate solution and producing carbon es'ta, simply heating the aqueous ammonium carboxylate solution
Low decomposition rate to ammonia and carboxylic acid.

However, surprisingly, as in the present invention,
The decomposition of ammonium carboxylate and the decomposition of ammonium carboxylate at low temperature can be achieved by using a cation exchange resin and an organic solution adsorbed on the resin and having the ability to remove Ia for nine ammonium cations.
It can be carried out quantitatively and also recovers ammonia and carboxylic acid! All of this has been greatly improved.

11 The present invention can significantly reduce the evaporation time t1 of water and organic solvent used for recovery of ammonia and carboxylic acid when compared with conventional methods.

Energy costs are low, making it an economically advantageous method.

(Example) Hereinafter, this will be explained in more detail with reference to Examples.

Example 1 Acrylic acid-based cation exchange resin (Mitsubishi Kasei DIAIO
NWK-20) into a jacketed glass column (20
φ, 1 m) after filling. Jacket part [53C hot water? The temperature inside the column was kept at 500℃. Then 0
10.5 in- of an aqueous solution of ammonium methacrylate containing 1 ton of methoxyhydroquino/1 ton was added to sa
The liquid was adjusted to C and was passed through the preheater and passed through the column, and the effluent was sampled in 202 increments.The ammonia and methacrylic acid in each sampling was analyzed by gas chromatography, and the sampling consensus was approximately 3,007.
Methacrylic acid began to be detected at 170
Ammonium cations began to be detected at f sampling. Sampling was stopped when the concentration of ammonium cations in the effluent sample reached 1.8% by weight, and the total amount of 7' methacrylic acid obtained in step 1 was determined by neutralization titration. 620mm
tT Atsushi. After 7 tons, the maximum concentration of the obtained aqueous methacrylic acid solution was 14.4% by weight. Next, when fi99C hot water 'e fAt, L and the ammonium methacrylate aqueous solution remaining in the column were collected from the top of the column, an ammonium methacrylate aqueous solution of 101 molar mass was obtained (0 as ammonium methacrylate). What is the mouth yield?
7) Pressure = 99 C while maintaining t 0 kg 7 cm
IC6N4 adjustment t preheat a? through.

Flow methanol from the bottom of the column as a total removal solvent fc,
Attach a condenser to the end and drain the effluent from the top of the 9th column for about 15y'.
When the methanol and ammonia gold in each sample was analyzed by gas chromatography, methanol and ammonia began to be detected at the foot of Zangling at about 2202, and about 14 U) WV
When the mixture was mixed, a methanol solution of ammonia with a concentration of 1.4 times was obtained. Sampling was carried out until no ammonia flowed out, and the ammonia in each sample was added to determine the total amount.

It became 610 mmot.

Example 2 Acrylic acid-based cation exchange resin (Mitsubishi Kasei lAl0
NWK-20) into a jacketed glass column (20
After filling the column (φ, 1 m), melt water from the jacket section &'C47C is poured to check the temperature inside the column. 12. of ammonium methacrylate containing 0.1% by weight hydroquinone in the primary held at 45C. Qii% aqueous solution was adjusted to 45Cic and passed through the column through a Fumiko heater, and the effluent was 30%
Sample one by one. Sampling consensus is 3001
Effluent from 150 to 4501? Take it, this is 24
01 Inphoron was brought into contact with the liquid at room temperature, and the methacrylic [f-extracted] in the effluent was 100f.
After separating the liquid in a separatory funnel, it was put into a 2-soawt Nana-type flask equipped with a fractionator tube together with 0 and 1 f of hydroquinone, and the whole distillation was carried out at about 30,011 Hg. obtained, 0 at the bottom of the can
．． 42 methacrylic acid remained. Next, to collect the ammonium methacrylate aqueous solution remaining in the column, 45C water was passed through the top of the column, and more than 99% of the solution was recovered. Next, reduce the column pressure to 1
0 kg/cd, the inside of the column was adjusted to 99C, and then ethyl alcohol was poured as a desorption solvent from the bottom of the column through a preheater. Ethyl alcohol containing ammonia flows out from the top of the nine column equipped with a cooler fif60.
After sampling at 0f, put 1 ton of water into a flask equipped with a reflux condenser and a sulfuric acid water trap, and perform air bubbling with a capillary, 700 + uH.
After distillation was carried out at 40 g for 7 t and distillation was carried out for 2 hours, the amount of ammonia collected in the sulfuric acid water trap was determined by reverse neutralization titration and found to be 570 mmo7. Deat skin.

Examples 5 to 7 The same operations as in Example 2 were conducted to recover carboxylic acid and ammonia from various ammonium carboxylate aqueous solutions. The results are shown in Table 1.

Comparative example 1 Helipack gourd filled with 2 gold and 9 packed tower (18φ×15On
In a 7ts o o-flask equipped with
[Add 200F and 0.2 P'i of hydroquinone.

The reflux ratio was set to 5 with the timer setting, and the tower top pressure was set to 575.
Distilled as lllHg. Tower bottom * @ degree t880
When the ammonia aqueous solution started to be distilled from the top of the column, the temperature at the bottom of the column rose to 110C five hours after the start of distillation, and the distillation was stopped at the bottom. During that time, the concentration of aqueous ammonia obtained from the top of the tower was 1081, and its concentration was 3.
It is 5-layered Jiyu, and it is prepared with ammonium methacrylate.
-100% and the ammonia decomposition rate at 9 o'clock is 24 kilns. Oh.

The rate of deterioration to methacrylamide is approximately 2%, and the rate of deterioration to 1 polymer is approximately 1.5%.

Comparative Example 2 75% by weight aqueous solution of ammonium inobutyrate 2001 gold,
Distillation was carried out using the same equipment and operating conditions as in Comparative Example 1. The bottom liquid temperature was raised to 12C,
Distillation of ammonia aqueous solution begins from the top of the column, and distillation begins 5
After an hour, when the temperature at the bottom of the column rose to 165 C''!, the distillation was started with 502 ml of ammonia water obtained from the top of the column during that time.

Its hardness is 16% by weight, and the ammonia decomposition rate is 52% when the charged ammonium isobutyrate f is 100%. However, about 20% deterioration to isobutyric acid amide was observed.

Claims (1)

[Claims] In the method of separating carboxylic acid and ammonia from an aqueous ammonium carboxylate solution, an aqueous carboxylic acid solution is obtained by adsorbing ammonium cations to a cation exchange resin, and the ammonium cations adsorbed to the resin are desorbed as ammonia using an organic solvent. A method for producing a carboxylic acid from an aqueous solution of ammonium carboxylate, the method comprising recovering the carboxylic acid from an aqueous solution of ammonium carboxylate.