JP5317836B2 - Method for producing alkyl sulfide compound - Google Patents

Description

  The present invention relates to a method for producing an alkyl sulfide compound that is mainly used as a raw material for synthesizing an alkyl sulfone compound that is useful as a solvent for electrochemical devices.

  The sulfide compound is a synthetic raw material such as a sulfone compound. Sulfone compounds are used as extraction solvents and various reaction solvents because of their high stability. In recent years, it has been used as a solvent for electrochemical devices by utilizing the electrical stability of sulfone compounds.

  In order to produce these sulfone compounds, a method of oxidizing sulfide compounds is common. Among them, there are few reports of industrially useful synthesis methods for alkyl sulfide compounds. So far, a method using a Grineer reagent is known as a method for synthesizing an alkyl sulfide compound.

For example, as shown in the following reaction formula, a method of synthesizing ethyl isobutyl sulfide by reacting diethyl disulfide or diethyl sulfide with an isobutyl grinder reagent (Non-patent Document 1),

In addition, as shown in the following reaction formula, a method of synthesizing ethyl isobutyl sulfide by reacting 2-methyl-1-thiocyanopropane with an ethyl grinder reagent has been reported (Non-patent Document 2).

  However, these methods are unstable in the air and require a Grineer reagent with a high risk of ignition, and thus cannot be said to be an industrially advantageous synthesis method.

In addition, as shown in the following reaction formula, a production method in which an alkylthiol is added to an unsaturated compound such as propylene has also been reported (Non-patent Document 3).

  However, since this method uses propylene which is easily polymerized, it is difficult to control, and since there are a plurality of reactive sites, it is easy to generate by-products and is not an industrially advantageous synthesis method.

On the other hand, a method using an alkyl halide is highly safe and suitable for large-scale synthesis. For example, as shown in the following reaction formula, a method of synthesizing ethyl isopropyl sulfide by reacting isopropyl bromide and ethanethiol in ethanol in the presence of potassium hydroxide has been reported (Non-Patent Document 4).

  However, this method has a yield as low as about 50%, and there are problems such as costly recovery of the solvent and reduction in production efficiency, and it is difficult to say that this is an industrially suitable production method.

Bulletin de la Societe Chimique de France (1906), (3) 35,166 Journal of the American Chemical Society (1920), 42, 2369 Journal of the American Chemical Society (1938), 60, 2452 Journal of Mass Spectrometry (1999), (6) 34,601

  An object of the present invention is to provide a method for obtaining an alkyl sulfide compound in a high yield in a safe and simple manner.

  The present invention relates to a method for producing an alkyl sulfide compound as shown below.

  Item 1. Formula (1);

（式中、Ｒ^１は、炭素数が１〜３のアルキル基を示す。）で表されるアルキルチオールを、還元剤存在下、塩基を用いて、式（２）；

(Wherein R ¹ represents an alkyl group having 1 to 3 carbon atoms), using a base in the presence of a reducing agent, formula (2);

（式中、Ｒ^１は、式（１）と同じアルキル基を示し、Ｍは、アルカリ金属原子を示す。）で表されるアルキルチオール塩とし、これと式（３）；

(Wherein R ¹ represents the same alkyl group as in formula (1), and M represents an alkali metal atom), and this and formula (3);

（式中、Ｒ^２は、炭素数３〜５のアルキル基を示し、Ｘは、ハロゲン原子を示す。）で表されるアルキルハライドとを、相間移動触媒存在下、反応させて得られる式（４）；

(Wherein R ² represents an alkyl group having 3 to 5 carbon atoms, and X represents a halogen atom) and an alkyl halide represented by the reaction in the presence of a phase transfer catalyst ( 4);

（式中、Ｒ^１は、式（１）と同じアルキル基を示し、Ｒ^２は式（２）と同じアルキル基を示す。）で表されるアルキルスルフィドの製造方法。

(Wherein R ¹ represents the same alkyl group as in formula (1), and R ² represents the same alkyl group as in formula (2)).

  Item 2. Item 2. The method for producing an alkyl sulfide according to Item 1, wherein the reducing agent is sodium borohydride.

  Item 3. Item 3. The method for producing an alkyl sulfide according to Item 1 or 2, wherein the phase transfer catalyst is tetra-n-butylammonium bromide.

  Examples of the alkyl thiol represented by the formula (1) used in the present invention include methane thiol, ethane thiol, 1-propane thiol, and 2-propane thiol.

  Examples of the base used when the alkylthiol is converted to an alkylthiol salt represented by the formula (2) by using a base in the presence of a reducing agent include, for example, hydroxide such as sodium hydroxide and potassium hydroxide. Mention may be made of alkali metals, alkali carbonates such as sodium carbonate and potassium carbonate, and alkali metal alcoholates such as sodium methylate and sodium ethylate. Of these, sodium hydroxide is preferably used because of its availability.

  The use ratio of the base is, for example, preferably 0.5 to 5.0 mol, more preferably 0.8 to 2.0 mol with respect to 1 mol of alkylthiol. When the use ratio of the base is less than 0.5 mol, the yield of the alkyl sulfide compound may be reduced, and when it exceeds 5.0 mol, the viscosity of the reaction solution may increase and stirring may become difficult. is there.

  Examples of the reducing agent include sodium borohydride, lithium borohydride, lithium aluminum hydride, sodium cyanoborohydride, diisopropylaluminum hydride, and the like. Of these, sodium borohydride is preferably used because of its availability.

  The ratio of the reducing agent to be used is, for example, preferably 0.001 to 1.0 mol, and more preferably 0.01 to 0.2 mol, with respect to 1 mol of alkylthiol. When the use ratio of the reducing agent is less than 0.001 mol, there is a possibility that an alkyl disulfide as an impurity may be formed. When it exceeds 1.0 mol, the viscosity of the reaction solution may be increased and stirring may be difficult. is there.

  Examples of the alkyl halide represented by the formula (3) used in the present invention include normal propyl chloride, isopropyl chloride, normal butyl chloride, isobutyl chloride, 1,1-dimethylethyl chloride, normal pentyl chloride, 1,2- Dimethylpropyl chloride, 2-methylbutyl chloride, 3-methylbutyl chloride, 2,2-dimethylpropyl chloride, normal propyl bromide, isopropyl bromide, normal butyl bromide, isobutyl bromide, 1,1-dimethylethyl bromide, normal pentyl bromide, 1,2-dimethylpropyl bromide, 2-methylbutyl bromide, 3-methylbutyl bromide, 2,2-dimethylpropyl bromide, etc.

  The proportion of the alkyl halide used is, for example, preferably 0.5 to 10 mol, and more preferably 0.8 to 5.0 mol, with respect to 1 mol of alkylthiol. When the usage-amount of an alkyl halide is less than 0.5 mol, reaction may not be completed and there exists a possibility that a yield may fall. If it exceeds 10 moles, the purity of the resulting alkyl sulfide compound may be reduced.

  Examples of the phase transfer catalyst used in the reaction of the alkylthiol salt represented by the formula (2) and the alkyl halide represented by the formula (3) include benzyltriethylammonium bromide, benzyltrimethylammonium bromide, and hexadecyltriethylammonium. Quaternary ammonium salts such as chloride, dodecyltrimethylammonium chloride, tetra-n-butylammonium bromide, tetraethylammonium chloride and trioctylmethylammonium bromide, and hexadodecyltriethylphosphonium bromide, hexadecyltributylphosphonium chloride and tetra-n-butylphosphonium A quaternary phosphonium salt such as chloride is preferably used. Of these, tetra-n-butylammonium bromide is preferably used from the viewpoint of improving the yield and economical efficiency.

  The amount of the phase transfer catalyst used is preferably 0.1 to 100 parts by weight, more preferably 0.1 to 10% by weight, based on 100 parts by weight of the alkyl halide. When the amount of the phase transfer catalyst used is less than 0.1 parts by weight, the reaction may not be completed and the yield may be reduced. When the amount exceeds 100 parts by weight, separation from the product becomes difficult and the production is difficult. There is a risk that the yield of the product will decrease.

  Examples of the reaction solvent used for the reaction of the alkyl thiol salt represented by the formula (2) and the alkyl halide represented by the formula (3) include water, tetrahydrofuran, 1,4-dioxane, methanol and ethanol. Etc. Among these, ethanol is preferably used from the viewpoint of improving the yield and economical efficiency.

  The amount of the reaction solvent used is preferably 10 to 5000 parts by weight and more preferably 100 to 1000 parts by weight with respect to 100 parts by weight of the alkylthiol. When the amount of the reaction solvent used is less than 10 parts by weight, stirring becomes difficult and the yield may be lowered. When it exceeds 5000 parts by weight, the production efficiency may be lowered and the economy may be deteriorated. is there.

The reaction temperature is preferably 30 to 120 ° C, and more preferably 60 to 110 ° C. If the reaction temperature is less than 30 ° C., it may be necessary for a long time to complete the reaction, and if it exceeds 120 ° C., side reactions may occur and the yield of the target compound may be reduced. The reaction time is, for example, about 1 to 30 hours.
The alkyl sulfide compound thus obtained can be obtained by washing with water and separating as necessary. Further, it can be isolated with increased purity by distillation.

  Specific examples of the sulfide compound include, for example, methyl normal propyl sulfide, methyl isopropyl sulfide, methyl normal butyl sulfide, methyl isobutyl sulfide, methyl 1,1-dimethylethyl sulfide, methyl normal pentyl sulfide, methyl 1,2-dimethylpropyl. Sulfide, methyl 2-methylbutyl sulfide, methyl 3-methylbutyl sulfide, methyl 2,2-dimethylpropyl sulfide, ethyl normal propyl sulfide, ethyl isopropyl sulfide, ethyl normal butyl sulfide, ethyl isobutyl sulfide, ethyl 1,1-dimethylethyl Sulfide, ethyl normal pentyl sulfide, ethyl 1,2-dimethylpropyl sulfide, ethyl 2-methylbutylsulfide , Ethyl 3-methylbutyl sulfide, ethyl 2,2-dimethylpropyl sulfide, propyl normal propyl sulfide, propyl isopropyl sulfide, propyl normal butyl sulfide, propyl isobutyl sulfide, propyl 1,1-dimethylethyl sulfide, propyl normal pentyl sulfide, propyl 1,2-dimethylpropyl sulfide, propyl 2-methylbutyl sulfide, propyl 3-methylbutyl sulfide, propyl 2,2-dimethylpropyl sulfide, isopropyl normal propyl sulfide, isopropyl isopropyl sulfide, isopropyl normal butyl sulfide, isopropyl isobutyl sulfide, isopropyl 1,1-dimethylethyl sulfide, isopropyl normal pe Chirusurufido, isopropyl 1,2-dimethylpropyl sulfide, isopropyl 2-methyl butyl sulfide and isopropyl 3-methyl-butyl sulfide, isopropyl 2,2-dimethyl-propyl sulfide, and the like. Among these, ethyl isopropyl sulfide, ethyl isobutyl sulfide, propyl isobutyl sulfide and isopropyl isobutyl sulfide are preferable as raw materials for synthesizing alkylsulfone compounds having excellent properties as solvents for electrochemical devices.

  INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a method for safely and easily obtaining a high yield of an alkyl sulfide compound used as a raw material for synthesizing an alkyl sulfone compound useful as a solvent for electrochemical devices.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

Example 1
Under a nitrogen atmosphere, 62.13 g (1.00 mol) of ethanethiol and 1.89 g (0.05 mol) of sodium borohydride were added to a 500 mL four-necked flask equipped with a stirrer, a thermometer and a condenser. This was cooled to 5 ° C. using an ice bath, and 346.67 g (1.30 mol) of 15 wt% sodium hydroxide aqueous solution was added to prepare an ethanethiol sodium salt aqueous solution. Separately, in a 1000 mL four-necked flask equipped with a stirrer, a thermometer and a condenser, under nitrogen atmosphere, 135.29 g (1.10 mol) of 2-bromopropane and 32.24 g of 50 wt% tetrabutylammonium bromide aqueous solution ( 0.05 mol) was added. This was heated to 50 ° C. using a hot water bath, and the whole amount of the ethanethiol sodium salt aqueous solution was added dropwise over 1 hour. This was kept warm for 2 hours and then separated to obtain 104.40 g of an upper organic layer (ethyl isopropyl sulfide). The yield of the obtained ethyl isopropyl sulfide was 100% with respect to ethanethiol, and the purity by gas chromatography analysis was 99.6%.

Example 2
In Example 1, 118.4 g of ethyl isobutyl sulfide was obtained in the same manner as in Example 1 except that 150.72 g (1.10 mol) of isobutyl bromide was used instead of 135.29 g of 2-bromopropane. The yield of the obtained ethyl isobutyl sulfide was 100% with respect to ethanethiol, and the purity by gas chromatography analysis was 95.0%.

Example 3
In Example 1, propanethiol 76.16 (1.00 mol) was used instead of ethanethiol 62.13 g, and isobutyl bromide 150.72 g (1.10 mol) was used instead of 2-bromopropane 135.29 g. Except for the above, 126.98 g of propylisobutyl sulfide was obtained in the same manner as in Example 1. The yield of the obtained propylisobutyl sulfide was 96% with respect to propanethiol, and the purity by gas chromatography analysis was 95.6%.

Example 4
In Example 1, 76.16 g (1.00 mol) of 2-propanethiol was used instead of 62.13 g of ethanethiol, and 150.72 g (1.10 mol) of isobutyl bromide was used instead of 135.29 g of 2-bromopropane. 124.33 g of isopropyl isobutyl sulfide was obtained in the same manner as in Example 1 except that was used. The yield of the obtained isopropyl isobutyl sulfide was 94% with respect to propanethiol, and the purity by gas chromatography analysis was 90.6%.

Claims (3)

Formula (1);

(In the formula, R ¹ represents an ethyl group ), an alkylthiol represented by the formula (2) using a base in the presence of a reducing agent;

(Wherein R ¹ represents the same alkyl group as in formula (1), and M represents an alkali metal atom), and this and formula (3);

(Wherein R ² represents a propyl group or an isobutyl group , and X represents a halogen atom) and an alkyl halide represented by the formula (4) obtained in the presence of a phase transfer catalyst;

(Wherein R ¹ represents the same alkyl group as in formula (1), and R ² represents the same alkyl group as in formula (2)). The method for producing an alkyl sulfide according to claim 1, wherein the reducing agent is sodium borohydride. The method for producing an alkyl sulfide according to claim 1 or 2, wherein the phase transfer catalyst is tetra-n-butylammonium bromide.