TW201726611A - Method for preventing decomposition of dimethyl sulfoxide - Google Patents

Abstract

The present invention is a method for preventing the decomposition of dimethyl sulfoxide, said method comprising adding sodium carbonate in an amount of 0.0005 to 2 g relative to 100 g of dimethyl sulfoxide contained in a dimethyl sulfoxide-containing liquid under an inert gas atmosphere. According to the present invention, it becomes possible to produce high-purity dimethyl sulfoxide when a dimethyl sulfoxide-containing liquid is distilled. According to the present invention, it also becomes possible to prevent the deterioration in quality of dimethyl sulfoxide when dimethyl sulfoxide is stored for a long period during the summer months or when dimethyl sulfoxide that is frozen during the winter months is heated for the purpose of melting the frozen dimethyl sulfoxide.

Description

Method for inhibiting decomposition of dimethyl sulfoxide

The present invention relates to a method of inhibiting the decomposition of dimethyl sulfoxide (DMSO).

Dimethyl hydrazine is widely used industrially as a polymerization or spinning solvent for polymers. In addition, the used dimethyl hydrazine recovery and reuse system has been widely carried out in the past. Industrially, when dimethyl hydrazine is recovered and reused, dimethyl hydrazine is purified by heating distillation. However, dimethyl hydrazine is less stable to heat. It is known that when dimethyl hydrazine is distilled under normal pressure, it will be slightly decomposed. When dimethyl hydrazine is produced by distillation or recovered and reused, the purity of dimethyl sulfoxide is lowered if the decomposition product of dimethyl hydrazine is present.

Therefore, when distilling dimethyl hydrazine, many examples are carried out under a reduced pressure atmosphere and at 100 ° C or lower.

As long as the dimethyl hydrazine can be distilled at a high temperature of 110 ° C or higher, a high vacuum is not required for distillation, and the pressure reducing device is not burdened, and the distillation apparatus is also simple and industrially suitable.

In the past, a method of adding a metal hydroxide such as sodium hydroxide or potassium hydroxide as a decomposition inhibitor of dimethyl sulfoxide has been known (refer to Patent Document 1). However, adding sodium hydroxide to dimethyl sulfoxide, if heated, may promote the decomposition of dimethyl hydrazine, and therefore, dimethyl hydrazine When purifying and purifying, a method which is safe and capable of inhibiting the decomposition of dimethyl hydrazine at a high temperature is required.

Prior technical literature Patent literature

Patent Document 1 Japanese Patent Publication No. 43-3765

It is an object of the present invention to provide a method for inhibiting the decomposition of dimethyl hydrazine by adding an additive which inhibits the decomposition of dimethyl hydrazine and is safe.

The present invention is a method for inhibiting the decomposition of dimethyl sulfoxide by adding 0.0005 g to 2 g of sodium carbonate to 100 g of dimethyl hydrazine in a liquid containing dimethyl hydrazine in an inert gas atmosphere.

In the method for inhibiting the decomposition of dimethyl sulfoxide of the present invention, even if dimethyl hydrazine is heated to a high temperature, dimethyl hydrazine is not easily decomposed. In the method of the present invention, when dimethyl hydrazine is distilled and recovered, the decomposition of dimethyl hydrazine is inhibited, and high-purity dimethyl hydrazine is obtained by distillation. In addition, it can be distilled at a high temperature, so that high vacuum equipment is not required, and purification can be performed at low cost. Sodium carbonate is safer and can work safer than conventional decomposition inhibition methods or purification methods using dangerous goods.

The method for inhibiting the decomposition of dimethyl sulfoxide of the present invention can suppress, for example, a long-term preservation in summer or a decrease in the quality of dimethyl hydrazine caused by heating of dimethyl hydrazine which is frozen in winter.

The method for inhibiting the decomposition of dimethyl hydrazine of the present invention can be used for dimethyl hydrazine used in various applications. For example, by inhibiting the decomposed dimethyl hydrazine by the method for inhibiting the decomposition of dimethyl hydrazine according to the present invention, a polymer which is polyacrylonitrile, cellulose, polyimine, polyfluorene, polyurethane or the like can be used. The solvent of the polymerization or spinning step, the stripping solution of the photoresist of the electronic material, the synthesis of the medical pesticide, the peeling of the lens mold, and the like. A stripping solution of the cleaning solution or paint.

The present invention is a method for inhibiting the decomposition of dimethyl hydrazine by adding sodium carbonate to a liquid containing dimethyl hydrazine.

The sodium carbonate may be an anhydride or a hydrate, and the hydrate is preferably a monohydrate or a decahydrate which is easily available.

Sodium carbonate can be added in the form of a powder or a solid. Sodium carbonate can also be added in the form of an aqueous solution. When sodium carbonate is added in the form of an aqueous solution, it can be continuously and automatically and uniformly added to, for example, a distillation apparatus or a storage container, and thus is safely suitable. The solubility of sodium carbonate in water 100 g is as high as 22 g at 20 °C. Therefore, sodium carbonate is added to a liquid containing dimethyl hydrazine, and distillation is carried out. When crystallization of sodium carbonate is carried out, the crystal of sodium carbonate in the distillation apparatus can be easily removed by washing with water.

The concentration at which sodium carbonate is made into an aqueous solution can be increased to a concentration that saturates at the temperature used. When sodium carbonate is added in the form of an aqueous solution, the concentration of sodium carbonate is preferably 0.1 to 35 g, preferably 0.2 to 30 g, per 100 g of water. More preferably 1~30g. The best is 10~25g.

The amount of sodium carbonate added is 0.0005 g to 2 g with respect to 100 g of dimethyl sulfoxide in the liquid. The amount of sodium carbonate added is preferably 0.001 g to 1.5 g, and preferably 0.001 g to 1 g, based on 100 g of dimethyl sulfoxide in the liquid. When the amount added is less than 0.0005 g, the decomposition inhibiting effect is insufficient. When the amount of addition is more than 2 g, when the temperature in winter is 0° C. or less, the solubility in water is low. Therefore, when adding as an aqueous solution, a large amount of water needs to be added.

In the present invention, when the sodium carbonate is added to the liquid containing dimethyl hydrazine, the liquid containing dimethyl hydrazine may be distilled before the distillation, or the impurity having a boiling point lower than that of the dimethyl hydrazine may be added. After the distillation, it was added, followed by distillation.

In the present invention, decomposition of dimethyl sulfoxide is inhibited in an inert gas atmosphere. The inert gas atmosphere means a nitrogen gas, a carbon dioxide gas, a helium gas or an argon atmosphere, and may be composed of one gas or a mixed gas of two or more gases. The inert gas atmosphere is preferably a nitrogen atmosphere. For example, when a liquid containing dimethyl hydrazine is distilled, in the case of distillation under air, dimethyl hydrazine is easily decomposed. When the liquid containing dimethyl hydrazine is heated under air, dimethyl hydrazine is easily decomposed.

In the present invention, when distilling a liquid containing dimethyl hydrazine, it is preferred to distill dimethyl hydrazine under an inert gas atmosphere under normal pressure to reduced pressure. In the case where the difference between the impurity to be removed and the boiling point of dimethyl hydrazine is small, the distillation is carried out at a reduced pressure in the vicinity of normal pressure or normal pressure. By distillation under a normal pressure or a normal pressure near a normal pressure, the difference in boiling point between the impurity and the dimethyl hydrazine is increased, and the impurities are easily removed.

Conventionally, when a liquid containing dimethyl hydrazine is distilled, dimethyl hydrazine is decomposed, and therefore it is distilled under reduced pressure at 110 ° C or lower. The method for inhibiting the decomposition of dimethyl sulfoxide of the present invention can suppress the decomposition of dimethyl hydrazine even at a high temperature. Therefore, when a liquid containing dimethyl hydrazine is distilled, a high degree of vacuum is not required.

In the present invention, when the liquid containing dimethyl hydrazine is distilled, the temperature at the time of distillation is preferably 90 ° C or more and 191 ° C or less, preferably 100 ° C or more and 180 ° C or less, more preferably 110 ° C or more and 170 ° C or less. When the temperature at the time of distillation is 90 ° C or more and 191 ° C or less, the apparatus is not burdened, and the distillation apparatus is also simple and industrially suitable.

When the liquid containing dimethyl hydrazine is not distilled, the storage temperature of the liquid containing dimethyl hydrazine is preferably 18 ° C or more and 120 ° C or less, preferably 25 ° C or more and 100 ° C or less.

In the present invention, when the liquid containing dimethyl hydrazine is distilled, the concentration of dimethyl hydrazine in the dimethyl hydrazine-containing liquid to be distilled is preferably 10% or more, and more preferably 20% or more. If the concentration of dimethyl hydrazine is less than 10%, there is a case where it is costly to distill off impurities.

When the liquid containing dimethyl hydrazine is not distilled, the concentration of dimethyl hydrazine in the liquid containing dimethyl hydrazine is preferably 10% or more, and more preferably 20% or more.

The liquid containing dimethyl hydrazine may contain water or the like in addition to dimethyl hydrazine.

In the present invention, a liquid component containing dimethyl hydrazine is mixed with a resin component, an insoluble matter, or a component which is easily colloidal when heated, or an acid or In the case of a strong base or an impurity which promotes decomposition such as a component which reacts with dimethyl hydrazine, it is preferred to remove, separate, deactivate, and neutralize impurities, such as filtration, adsorption separation, ion exchange resin, or alkali addition. .

In the case of distilling a liquid containing dimethyl hydrazine, the present invention can be applied to either batch distillation or continuous distillation. In the case of continuous distillation, it is preferred to continuously supply an aqueous solution of sodium carbonate before the distillation column.

In the present invention, when the liquid containing dimethyl hydrazine is distilled, it is preferably carried out by a distillation column having a theoretical number of plates of 1 to 50 in the distillation column, and more preferably a 3- to 40-stage distillation column.

Further, when the liquid containing dimethyl hydrazine is distilled, the sodium carbonate precipitated after the distillation can be disposed of or recycled.

In the present invention, when the liquid containing dimethyl hydrazine is not distilled, the sodium carbonate may be discarded or recycled.

In the present invention, the analysis of the decomposition rate of dimethyl hydrazine is carried out using gas chromatography using a capillary column.

The decomposition rate of dimethyl hydrazine after heating at 180 ° C for 24 hours is preferably 0.06 area% or less, more preferably 0.05 area% or less, and even more preferably 0.04 area% or less.

In the present invention, in the case where 7 g of water is contained in 100 g of dimethyl sulfoxide, the dimethyl hydrazine decomposition rate after heating at 157 ° C for 5 hours is preferably 0.04 area% or less, and 0.02 area% or less is more. Preferably, 0.01 area% or less is more preferred.

In the present invention, the purity of the heated dimethyl sulfoxide is analyzed by gas chromatography using a capillary column.

In the present invention, the purity of dimethyl hydrazine after heating at 180 ° C for 24 hours is preferably 99.94% or more, and more preferably 99.95% or more.

In the present invention, when 7 g of water is contained in 100 g of dimethyl sulfoxide, the purity of dimethyl hydrazine after heating at 157 ° C for 5 hours is preferably 99.96% or more, more preferably 99.97% or more, and 99.98 is preferable. More than % is better.

In the present invention, the liquid containing dimethyl hydrazine is, for example, a reaction liquid containing dimethyl hydrazine obtained by a step of synthesizing by oxidation of a sulfide or the like; and contained in polyacrylonitrile, cellulose, and polyimine. a waste liquid of dimethyl hydrazine used in a polymerization or spinning step of a polymer such as polyfluorene or polyurethane; and a waste liquid of dimethyl hydrazine used as a stripping liquid of a photoresist as an electronic material; Contains peeling as a lens mold or the like. A waste liquid of dimethyl hydrazine used for the cleaning liquid; a waste liquid containing dimethyl hydrazine used as a synthetic solvent for medical pesticides; or a waste liquid containing dimethyl hydrazine used as a peeling liquid for a paint. These dimethyl hydrazine-containing liquids can be obtained by distillation to obtain high-purity dimethyl hydrazine. Further, according to the present invention, it is possible to suppress the deterioration of the quality of dimethyl hydrazine caused by the long-term storage in the summer or the heating of the dimethyl sulfoxide which is frozen in winter.

Example

The invention will be specifically described below by way of examples. The various measured values used in the examples and the like of the present invention were measured by the following measurement methods.

(1) GC purity (area%) of dimethyl sulfoxide

The measurement was carried out by gas chromatography (hereinafter abbreviated as "GC") under the following conditions.

Using the machine Shimadzu Corporation GC-2010 (FID)

Column DB-WAX 0.25mm × 60m, film thickness 0.25μm

Carrier gas He 165.7kPa

Column heating condition

35 ° C → 7 ° C / min → 140 ° C × 10 minutes → 15 ° C / min → 250 ° C × 10 minutes

Injection inlet temperature 200 ° C

Detector temperature 250 ° C

FID

Air 400ml/min

H ₂ 40ml/min

Supply 30ml/min

Split ratio 14

Analytical sample preparation The sample was filtered through a 0.5 μm PTFE syringe filter.

The injection amount was 1.0 μl.

(2) Decomposition rate (area%) when there is no water in the system

The GC purity (area%) of dimethyl hydrazine which was heated at 180 ± 2 ° C for 24 hours was measured in the same manner as in (1). The difference in GC purity from the blank sample was defined as the decomposition rate.

(3) Decomposition rate (area%) when water is contained in the system

(1) The GC measurement did not detect water. Then, 7 g of water was added to 100 g of dimethyl sulfoxide, and the mixture was heated at 157 ± 2 ° C for 5 hours under reflux to obtain a decomposition rate as follows.

The liquid containing dimethyl hydrazine before heating (referred to as a liquid before heating) and the liquid containing dimethyl hydrazine after heating (referred to as a liquid after heating) were measured in the same manner as in (1). The GC purity (area%) of the Aachen was determined by the following calculation formula to determine the decomposition rate when water was contained.

Decomposition rate (area%) when water is contained = (GC purity (area%) of dimethyl sulfoxide when liquid before heating contains water - GC purity (area%) of dimethyl hydrazine when liquid after heating contains water) .

(4) Amount of oxide (area%)

The amount (area%) of dimethylhydrazine contained in dimethyl hydrazine heated at 180 ± 2 ° C for 24 hours was measured in the same manner as in (1), and the amount of the oxide was determined.

(Example 1)

In a 300 ml three-necked flask equipped with a Dairy condenser, a stirrer, and a thermometer, 200 g of dimethyl hydrazine (GC purity: 99.997 area%) and 0.002 g of sodium carbonate as an additive (0.001 g based on 100 g of dimethyl sulfoxide) were placed. After replacing the gas in the flask with nitrogen gas, a rubber balloon filled with nitrogen gas was attached to the upper portion of the Dairy condenser tube to be in a sealed state. Using a 192 ° C oil bath, the time at which the internal temperature reached 178 ° C was taken as the starting point, and heating was carried out at 180 ± 2 ° C for 24 hours. After cooling to below 25 ° C, the liquid attached to the wall of the flask was mixed with the internal liquid. The GC purity of this dimethyl sulfoxide was 99.966 area%. The decomposition rate obtained from this GC purity is disclosed in Table 1. Further, the amount of the oxide was 0.00 area%.

(Examples 2 to 4)

The same procedure as in Example 1 was carried out except that the amount of sodium carbonate added was changed as described in Table 1. The results of GC purity, decomposition rate, and amount of oxide of dimethyl hydrazine in each example are shown in Table 1.

(Comparative Example 1)

The same procedure as in Example 1 was carried out except that sodium carbonate was not added. The results of the GC purity, the decomposition rate, and the amount of oxide of the dimethyl hydrazine of Comparative Example 1 are shown in Table 2.

(Comparative examples 2 to 6)

The same procedure as in Example 1 was carried out except that the type of the additive and the amount of the additive to be added were changed as described in Table 2. The results of GC purity, decomposition rate, and amount of oxide of dimethyl hydrazine in each comparative example are shown in Table 2.

(Comparative examples 7 to 8)

The same procedure as in Example 1 was carried out except that the amount of sodium carbonate added was changed as shown in Table 2, and it was carried out in an air atmosphere. The results of GC purity, decomposition rate, and amount of oxide of dimethyl hydrazine in each comparative example are shown in Table 2.

In the cases of Examples 1 to 4, no dimethyl hydrazine was detected in dimethyl hydrazine. In addition, the decomposition of dimethyl hydrazine is extremely rare.

In the case of Comparative Examples 1 to 8, the decomposition of dimethyl sulfoxide was more than that of Examples 1 to 4. Further, in the case of Comparative Examples 2 and 7 to 8, dimethylhydrazine was detected in dimethyl sulfoxide.

(Example 5)

200 g of dimethyl hydrazine was placed in a 300 ml three-necked flask equipped with a Dairy condenser, a stir bar and a thermometer. Next, 0.2 g of sodium carbonate as an additive (0.1 g based on 100 g of dimethyl sulfoxide) was dissolved in 14 g of distilled water (7 g based on 100 g of dimethyl sulfoxide). The GC purity of the dimethyl hydrazine in the liquid before the heating contained water was 99.997 area%. After replacing the gas in the flask with nitrogen gas, a rubber balloon filled with nitrogen gas was attached to the upper portion of the Dairy condenser tube to be in a sealed state. Using a 190 ° C oil bath, the time at which the internal temperature reached 155 ° C was taken as the starting point, and heating was carried out at 157 ± 2 ° C for 5 hours under reflux. After cooling to below 25 ° C, the liquid attached to the wall of the flask was mixed with the internal liquid. When the heated liquid contained water, the GC purity of dimethyl hydrazine was 99.997 area%. The decomposition rate in the case of containing water obtained by this GC purity is shown in Table 3.

(Example 6)

The same procedure as in Example 5 was carried out except that the amount of sodium carbonate added was changed as described in Table 3. Table 3 shows the results of the GC purity of dimethyl hydrazine and the decomposition rate when water is contained in the liquid before heating and the liquid after heating.

(Comparative Example 9)

The same as Example 5 except that 0.1 g of sodium hydroxide was added as shown in Table 3. Table 3 shows the results of the GC purity of dimethyl sulfoxide and the decomposition rate when water was contained in the liquid before heating of the comparative example 9 and the liquid after heating.

In the case of Comparative Example 9, the decomposition of dimethyl sulfoxide was more than that of Examples 5 to 6.

[Industrial availability]

According to the present invention, when a liquid containing dimethyl hydrazine is distilled, high purity dimethyl hydrazine can be obtained. Further, according to the present invention, it is possible to suppress the deterioration of the quality of dimethyl hydrazine caused by the long-term storage in the summer or the heating of the dimethyl sulfoxide which is frozen in winter.

The dimethyl hydrazine which inhibits decomposition by the method for inhibiting the decomposition of dimethyl hydrazine according to the present invention can be used as a polymer of polyacrylonitrile, cellulose, polyimine, polyfluorene, polyurethane or the like. Solvent in the polymerization or spinning step, stripping solution of photoresist of electronic materials, synthesis of medical pesticides, peeling of lens molds, etc. A stripping solution of the cleaning solution or paint.

Claims (6)

A method for inhibiting the decomposition of dimethyl sulfoxide by adding 0.0005 g to 2 g of sodium carbonate to 100 g of dimethyl hydrazine in a liquid containing dimethyl hydrazine in an inert gas atmosphere. A method for inhibiting decomposition of dimethyl hydrazine as claimed in claim 1, wherein sodium carbonate is added as an aqueous solution to be added. The method for inhibiting the decomposition of dimethyl hydrazine according to claim 1 or 2, wherein the dimethyl hydrazine-containing liquid is purified by distillation in an inert gas atmosphere, and is added to a liquid containing dimethyl hydrazine. Sodium carbonate. A method of inhibiting the decomposition of dimethyl hydrazine according to claim 1 or 2, wherein the inert gas atmosphere is a nitrogen atmosphere. The method for inhibiting the decomposition of dimethyl hydrazine according to claim 1, wherein the dimethyl hydrazine has a GC purity of 99.94 area% or more after heating at 180 ° C for 24 hours. The method for inhibiting the decomposition of dimethyl hydrazine according to claim 2, wherein the decomposition rate of dimethyl hydrazine after heating at 157 ° C for 5 hours is 0.04 area% or less.