JP5466383B2 - Process for producing alkyl N, N-dimethylcarbamate, and detergent and polymer solution containing alkyl N, N-dimethylcarbamate - Google Patents

Description

  The present invention relates to a method for producing alkyl N, N-dimethylcarbamate, and a detergent and polymer solution containing alkyl N, N-dimethylcarbamate.

  The carbamate compound is important as an intermediate for pharmaceuticals, agricultural chemicals, and the like, and various production methods (for example, a production method by reaction of isocyanate and alcohol or a reaction using amine, alcohol and phosgene) are known. Patent Document 1 discloses a method for producing carbamate, which comprises reacting an organic carbonate with a primary or secondary amine in the presence of a Lewis acid. However, in all the examples, there are problems that the reaction temperature is 80 to 110 ° C., a large excess of carbonate is used, and the yield is low. Patent Document 2 discloses a method for producing carbamate using amidine or the like as a catalyst, but the efficiency in the examples is not sufficient. Patent Document 3 discloses a method for producing a carbamic acid ester derivative or the like using an alkali metal hydroxide or the like as a catalyst. Patent Document 4 discloses a method for producing carbamate, which is carried out by reacting carbonate and amine in the presence of a large amount of water. Although this method is excellent in yield, there is a problem that a large amount of energy is required for dehydration because water remains in the product. Patent Documents 5 and 6 disclose a method for producing carbamates by reacting an amine and an alcohol in supercritical carbon dioxide. However, this method requires high temperature and high pressure and is not economically advantageous.

  As described above, various techniques are known for the production of carbamate compounds, but considering the expected expansion of its use in the future, using inexpensive raw materials, the reaction temperature is around room temperature, There is a demand for a production method capable of suppressing the production.

By the way, when manufacturing parts and products in the electrical and electronic field, cleaning agents and solvents are used in the manufacturing process.
Conventionally, halogen compounds have been used as cleaning agents, but in recent years, alternatives have been developed in view of environmental problems and toxicity. Patent Document 7 discloses a cleaning agent mainly composed of N-methyl-2-pyrrolidone and a surfactant, and Patent Document 8 discloses tetrafurfuryl alcohol and a specific amine compound or a specific ester compound. Patent Document 9 discloses a detergent containing a nonionic surfactant and N-methylpyrrolidone, and Patent Document 10 discloses 2-pyrrolidone, γ-butyrolactone, N, A cleaning agent containing one kind selected from N-dimethylacetamide and water is disclosed. However, satisfactory performance and economy have not yet been obtained, and further technological development is required.

  Examples of use as the solvent include preparation of a polyvinylidene fluoride (PVDF) solution. PVDF is a resin having properties such as high strength, chemical resistance, heat resistance, pyroelectricity, and piezoelectricity, but has a problem of low solubility in common solvents. For this reason, the solvent used so far is limited to N-methylpyrrolidone and the like, and even in this case, the solubility is not always high.

  As compounds used in solvents and cleaning agents, various insoluble compounds can be dissolved, water solubility is high and water rinsing is possible, and they have a relatively low boiling point. It is important that it is easy to reuse. In addition, considering the amount of use, it is also important that mass production can be performed efficiently.

JP 47-11562 A JP-A-1-503627 Japanese Patent Laid-Open No. 52-14745 JP-A-3-275661 JP 2006-22043 A JP 2002-212159 A JP-A-49-128908 JP-A-3-243698 JP-A-4-68095 JP-A-6-65769

  The present invention has been made in view of the above circumstances, and provides a method for producing alkyl N, N-dimethylcarbamate, which uses an inexpensive raw material, has a reaction temperature near room temperature, and can suppress the formation of by-products. Providing a cleaning agent and a solvent having a low boiling point and capable of dissolving various poorly soluble compounds and having a high solubility in water; and The object is to provide a solution.

As a result of extensive research, the present inventors have produced alkyl N, N-dimethylcarbamate using specific raw materials and catalysts, and cleaning containing specific alkyl N, N-dimethylcarbamate. It has been found that the above problems can be achieved by the agent and the solvent. The present invention has been completed based on such findings.
That is, the present invention
1 General formula (I)

(R ¹ and R ² each independently represents an alkyl group having 1 to 4 carbon atoms.)
A dialkyl carbonate and dimethylamine represented by the general formula (II)

(X represents OH or SH.)
Wherein the reacting in at pin lysine derivative in the presence of a catalyst represented by the general formula (III)

(R ³ is R ¹ or R ² and represents an alkyl group having 1 to 4 carbon atoms.)
A method for producing an alkyl N, N-dimethylcarbamate represented by:
2 The method for producing an alkyl N, N-dimethylcarbamate according to the above 1, wherein the dialkyl carbonate is dimethyl carbonate or diethyl carbonate,
3 General formula (IV)

(R ⁴ represents an alkyl group having 1 to 4 carbon atoms.)
A detergent containing 50% by mass or more of an alkyl N, N-dimethylcarbamate represented by the formula:

4 General formula (IV)

(R ⁴ represents an alkyl group having 1 to 4 carbon atoms.)
A polymer solution obtained by dissolving a polymer in an alkyl N, N-dimethylcarbamate represented by
5. The polymer solution according to 4 above, wherein the polymer is at least one selected from polyvinylidene fluoride, syndiotactic polystyrene, polyamide, and polyimide.

  According to the present invention, a cleaning agent and a solvent excellent in performance can be obtained. Furthermore, alkyl N, N-dimethylcarbamate used for the cleaning agent and the solvent can be efficiently produced in large quantities.

  In the present invention, a specific dialkyl carbonate and dimethylamine are reacted in the presence of a specific catalyst to give a general formula (III)

To produce an alkyl N, N-dimethylcarbamate represented by: In the general formula (III), R ³ is R ¹ or R ² and represents an alkyl group having 1 to 4 carbon atoms.

  In the present invention, the dialkyl carbonate is represented by the general formula (I)

The dialkyl carbonate represented by these is used. In the general formula (I), R ¹ and R ² each independently represents an alkyl group having 1 to 4 carbon atoms. The alkyl group having 1 to 4 carbon atoms represented by R ¹ and R ² may be linear or branched, and may be a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, Mention may be made of isobutyl, sec-butyl and tert-butyl groups. R ¹ and R ² may be the same or different from each other, but R ¹ and R ² are both a methyl group or an ethyl group from the viewpoint of the performance of the resulting alkyl N, N-dimethylcarbamate and the availability of raw materials. It is preferable that

  When alkyl N, N-dimethylcarbamate is used as a cleaning agent or solvent, the dialkyl carbonate is preferably dimethyl carbonate or diethyl carbonate from the viewpoints of dissolution performance and boiling point.

Dimethylamine may be used in a solution state or in a gas state.
The use ratio (molar ratio) of the dialkyl carbonate and dimethylamine is preferably 0.5: 1 to 1: 0.5, and more preferably 0.7: 1 to 1: 0.7. The reaction proceeds even if either of the raw materials is excessive, but this is not economically preferable.

  In the present invention, the catalyst is represented by the general formula (II)

Using the in pin lysine derivative represented. In the general formula (II), X represents OH or SH, and a pyridine derivative substituted at the 2-position or 4-position is preferred.
Examples of the pyridine derivative represented by the general formula (II) include 2-hydroxypyridine, 4-hydroxypyridine, 2-mercaptopyridine, 4-mercaptopyridine, and the like. Alternatively, two or more kinds may be used in combination.
Although the usage-amount of a catalyst should just be determined suitably, it is 0.5-20 mass% normally with respect to the total amount of a dialkyl carbonate and a dimethylamine, Preferably it is 1-10 mass%.

A reaction solvent may be used as long as it does not dissolve the respective raw materials and inhibit the reaction. Specifically, benzene, toluene, ethyl acetate, methyl acetate, dioxane, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, methanol, ethanol, propanol and the like can be used, and methanol is particularly preferable.
The reaction temperature is usually 10 to 100 ° C, preferably 20 to 70 ° C. If the temperature is too high, a urea derivative may be generated. The reaction time is usually 1 to 50 hours, preferably 2 to 6 hours. The reaction pressure may be determined as appropriate, but is usually performed at normal pressure.
The alkyl N, N-dimethylcarbamate of the present invention can be produced by the above reaction. Moreover, you may perform a refinement | purification process as needed. The purification treatment may be appropriately determined, and examples thereof include distillation.

  The cleaning agent of the present invention has the general formula (IV)

(R ⁴ represents an alkyl group having 1 to 4 carbon atoms.)
And an aqueous solution of the above alkyl N, N-dimethylcarbamate is particularly preferable. In the general formula (IV), examples of the alkyl group having 1 to 4 carbon atoms represented by R ⁴ include the same ones as exemplified in the description of R ¹ and R ² in the general formula (I). Of these, a methyl group and an ethyl group are preferable from the viewpoint of performance. The alkyl N, N-dimethylcarbamate represented by the general formula (IV) may be used alone or in combination of two or more. The content of alkyl N, N-dimethylcarbamate is 50% by mass or more based on the total amount of the cleaning agent, preferably 50 to 95% by mass, more preferably 70 to 90% by mass. If the content of alkyl N, N-dimethylcarbamate is less than 50% by mass, the cleaning effect tends to be lowered. Further, the upper limit of the N, N-dimethylcarbamate alkyl content is not particularly affected in terms of the cleaning effect, but it is preferable that the upper limit is satisfied in consideration of economy and corrosion of the apparatus.

  The cleaning agent of the present invention may contain an additive, and examples thereof include a surfactant, a sequestering agent, and an antioxidant.

Surfactants include anionic surfactants such as alkyl sulfates, alkyl polyoxyethylene sulfates, alkylbenzene sulfonates, α-olefin sulfonates, monoalkyl phosphates; alkyltrimethylammonium salts, dialkyldimethylammonium salts Cationic surfactants such as salts, alkylammonium salts, alkylbenzyldimethylammonium salts; amino acid type amphoteric surfactants, betaine type amphoteric surfactants such as alkylcarboxybetaines and alkylsulfobetaines, imidazoline type amphoteric surfactants, etc. Amphoteric surfactants: Nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, fatty acid diethanolamides, and alkyl dimethyl amine oxides.
The said surfactant may be used individually by 1 type, or may be used in combination of 2 or more type. The content of the surfactant is usually 0.05 to 10% by mass, preferably 0.1 to 5% by mass with respect to the total amount of the cleaning agent. If it is less than 0.05% by mass, the cleaning action tends to be low, and if it exceeds 10% by mass, the bubbles are blown out and the rinsing property tends to be low.

As sequestering agents, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, N-hydroxyethylethylenediaminetriacetic acid, ethylenediaminetetrapropionic acid, triethylenetetraminehexaacetic acid, ethylene glycol dietherdiaminetetraacetic acid, cyclohexane-1,2-diaminetetra Aminocarboxylic acid substances such as acetic acid; glycolic acid, diglycolic acid, lactic acid, tartaric acid, carboxymethyltartaric acid, citric acid, malic acid, gluconic acid and other oxycarboxylic acids; acetic acid, monochloroacetic acid, oxalic acid, succinic acid, carboxy Carboxylic acid substances such as methyl succinic acid and carboxymethyloxysuccinic acid; pyrophosphoric acid, tripolyphosphoric acid, hexametaphosphoric acid, zeolite and the like.
The said sequestering agent may be used individually by 1 type, or may be used in combination of 2 or more type. The content of the sequestering agent is usually 0.1 to 20% by mass, preferably 1 to 10% by mass, based on the total amount of the cleaning agent. If it is less than 0.1% by mass, the cleaning action tends to decrease, and even if it exceeds 20% by mass, it is difficult to obtain an effect commensurate with the blending amount.

Antioxidants include 2,6-di-tert-butyl-4-methylphenol, 2,5-di-tert-butylhydroquinone, 2,6-di-tert-butyl-α-dimethylamino-p-cresol Monophenolic compounds such as 4,4′-bis (2,6-di-tert-butylphenol), 4,4′-methylene-bis (2,6-di-tert-butylphenol), 2,2′- Bisphenol compounds such as methylene-bis (4-methyl-6-tert-butylphenol), 4,4′-butylidene-bis (3-methyl-6-tert-butylphenol); 4,4′-thiobis (3-methyl- 6-tert-butylphenol), 2,2′-thiobis (6-tert-butyl-o-cresol), 2,2′-thiobis (4-methyl-6-tert-butyl) Thiobisphenol compounds such as phenol); tetrakis [methylene-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane, tris (2-methyl-4-hydroxy-5-tert-butyl) -Tris or tetrakisphenol compounds such as phenol) butane; phosphite antioxidants such as triphenyl phosphite, trisnonylphenyl phosphite, tris (mono and di-nonylphenyl) phosphite; dilauryl thiodipropionate And sulfur-based antioxidants such as distearyl thiodipropionate.
The said antioxidant may be used individually by 1 type, or may be used in combination of 2 or more type. Content of antioxidant is 0.01-1.0 mass% normally with respect to cleaning agent whole quantity.

  In the polymer solution of the present invention, an alkyl N, N-dimethylcarbamate represented by the above general formula (IV) is used as a solvent. Although there is no restriction | limiting in particular as a polymer used as a solute, According to this invention, the solution of hardly soluble polymers, such as a polyvinylidene fluoride, a syndiotactic polystyrene, polyamide, a polyimide, can be prepared.

The concentration of the polymer can be appropriately determined according to the purpose, but is usually 1 to 40% by mass, preferably 3 to 20% by mass. Moreover, you may add additives, such as antioxidant, as needed. As the antioxidant, those mentioned as additives for the cleaning agent can be used.
When preparing a polymer solution, you may heat as needed, for example, 20-120 degreeC is mentioned.
The polymer solution of the present invention can be used as a viscosity control agent, a dispersant, a coating agent, an adhesive, and a binder agent in, for example, polymer coating, cast film production, and fiber production such as hollow fiber.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.

Example 1
A 1000 ml reactor equipped with a stirrer and a thermometer was charged with 450 g of a methanol solution containing 100 g of dimethyl carbonate and 50 g of dimethylamine and 4.5 g of 2-hydroxypyridine, and stirred at 60 ° C. for 5 hours. After concentration of the reaction solution, atmospheric distillation was performed to obtain a product. The product was found to have the following structure (methyl N, N-dimethylcarbamate) by ¹ H-NMR measurement. The yield was 98.4 g, and the yield was 86%.

Example 2
A 200 ml reactor equipped with a stirrer and a thermometer was charged with 120 ml of a methanol solution containing 27.0 g of dimethyl carbonate, 13.2 g of dimethylamine and 2.5 g of 2-mercaptopyridine. Stirring was performed at 60 ° C. for 5 hours. Next, after distilling off low-boiling substances using an evaporator, a product was obtained by distillation. The yield was 30.7 g and the yield was 81%.

Example 3
In a 200 ml reactor equipped with a stirrer and a thermometer, 27.0 g of dimethyl carbonate and 2.8 g of 2-hydroxypyridine were placed. The temperature of the reactor was set to 60 ° C., and gaseous dimethylamine corresponding to 16 g was blown into the reactor at room temperature over 3 hours. After completion of the reaction, distillation was performed to obtain a product. The yield was 34.9 g and the yield was 92%.

Example 4
A 200 ml reactor equipped with a stirrer and a thermometer was charged with 27.0 g of dimethyl carbonate, 120 ml of a methanol solution containing 13.2 g of dimethylamine and 2.8 g of 4-hydroxypyridine. Stirring was performed at 60 ° C. for 5 hours. Next, after distilling off low-boiling substances using an evaporator, a product was obtained by distillation. The yield was 30.3 g, and the yield was 80%.

[Solubility test]
Example 5
(1) 0.1 g, 0.2 g, 0.3 g, 0.4 g, and 0.5 g of polyvinylidene fluoride manufactured by FluoroChem are added to 2 g of methyl N, N-dimethylcarbamate synthesized in Example 1, and 100 ° C. It was heated for 10 minutes to dissolve. As a result of visual evaluation, all the solutions were colorless and transparent and had fluidity.
(2) When 1.0 g of the above polyvinylidene fluoride and 2 g of methyl N, N-dimethylcarbamate synthesized in Example 1 were mixed, a colorless and transparent solution was obtained although there was almost no fluidity.
(3) A solution of 1.0 g of the above polyvinylidene fluoride and 9 g of methyl N, N-dimethylcarbamate synthesized in Example 1 was poured on a glass plate and allowed to stand at room temperature for 48 hours to obtain a cast film of polyvinylidene fluoride. I was able to.
Comparative Example 1
Each of 0.1 g, 0.2 g, 0.3 g, 0.4 g, and 0.5 g of polyvinylidene fluoride manufactured by FluoroChem was added to 2 g of N-methylpyrrolidone, and the mixture was heated and stirred at 100 ° C. for 10 minutes. As a result of visual evaluation, all the solutions became cloudy, and there was almost no fluidity of the solution using 0.3 g or more of the polymer.

Examples 6-8, Comparative Example 2
A cleaning liquid having the composition shown in Table 1 was prepared and a cleaning test (cleaning test 1) was performed. The results are shown in Table 1.
Examples 9-14
A predetermined amount of a surfactant shown in Table 2 was added to an aqueous solution of methyl N, N-dimethylcarbamate (80% by mass) to prepare a cleaning solution, and a cleaning test (cleaning test 1) was performed. The results are shown in Table 2.

[Cleaning test 1]
A weighed 100 mesh stainless steel wire mesh (50 mm x 40 mm) is dipped in quenching oil for quenching, immediately taken out and left to stand at room temperature for 3 hours (the adhered oil after 3 hours is constant at about 0.5 g) ). After weighing the mass of the wire mesh to which oil was attached, it was immersed in 200 g of cleaning liquid installed in a constant temperature ultrasonic cleaner previously maintained at 70 ° C., immediately cleaned with ultrasonic waves for 3 minutes, and then heated with 70 ° C. water for 1 minute. It was rinsed, dried at 60 ° C. for 1 hour, and its mass was measured. The oil removal rate was calculated by the following formula.
Oil removal rate (%) = 100 × (weight of oil attached to wire mesh before washing−weight of oil attached to wire mesh after washing) / (weight of oil attached to wire mesh before washing)

Examples 15-17
A cleaning test (cleaning test 2) was performed using a test piece (30 × 15 × 2 mm) of the material shown in Table 3 and a cleaning agent of an aqueous N, N-dimethylcarbamate methyl solution (80% by mass). The results are shown in Table 3.
Comparative Examples 3-5
A cleaning test was conducted in the same manner as in Examples 15 to 17 except that an aqueous methyl N, N-dimethylcarbamate solution (40% by mass) was used as the cleaning agent. The results are shown in Table 3.
[Cleaning test 2]
The test piece was dipped in marquen oil, immediately taken out, left suspended at room temperature for 30 minutes, and washed in the same manner using the same apparatus as in washing test 1. The surface of the test piece was evaluated by visual observation and cello tape (registered trademark) adhesion according to the following criteria. The results are shown in Table 3.
(Visually)
○ The oil has been completely removed.
X Oil remains.
(Cello tape (registered trademark) adhesion)
○ Cello tape (registered trademark) can be attached.
X Cellotape (registered trademark) peels off.

  According to the present invention, alkyl N, N-dimethylcarbamate can be produced efficiently. According to the production method, alkyl N, N-dimethylcarbamate can be produced in a large amount, and a high-performance detergent and solvent can be obtained.

Claims (5)

Formula (I)

(R ¹ and R ² each independently represents an alkyl group having 1 to 4 carbon atoms.)
A dialkyl carbonate and dimethylamine represented by the general formula (II)

(X represents OH or SH.)
Wherein the reacting in at pin lysine derivative in the presence of a catalyst represented by the general formula (III)

(R ³ is R ¹ or R ² and represents an alkyl group having 1 to 4 carbon atoms.)
A method for producing an alkyl N, N-dimethylcarbamate represented by the formula:   The method for producing an alkyl N, N-dimethylcarbamate according to claim 1, wherein the dialkyl carbonate is dimethyl carbonate or diethyl carbonate. Formula (IV)

(R ⁴ represents an alkyl group having 1 to 4 carbon atoms.)
A cleaning agent comprising an aqueous solution containing 70% by mass or more of an alkyl N, N-dimethylcarbamate represented by the formula, based on the total amount of the cleaning agent.   The detergent according to claim 3, further comprising 0.05 to 10% by mass of a surfactant based on the total amount of the detergent. Formula (IV)

(R ⁴ represents an alkyl group having 1 to 4 carbon atoms.)
In represented by N, N-di methylcarbamate alkyl, polymer solution obtained by dissolving the polyfluorinated vinylidene down.