JPS6151582B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel method for producing parahalogenothiophenol, and more specifically, it involves halogenating diphenyl sulfide in a nonpolar solvent to produce 4,4'-dihalogenodiphenyl sulfide. The present invention also relates to a method for producing halogenothiophenol, which is characterized in that it is then reacted with hydrogen sulfide in a high-temperature gas phase. Parahalogenothiophenols are valuable compounds as intermediates for pesticides, medicines, and dyes. Conventionally, various methods have been known for producing parahalogenothiophenol. US Pat. No. 3,331,205 and US Pat. No. 3,474,139 describe a method of chlorinating thiophenol to produce parachlorosulfenyl chloride, and then reducing this to produce chlorothiophenol. However, in this method, a considerable amount of the isomer orthochlorothiophenol is produced, and the boiling points of the two are similar, making purification very troublesome.
Therefore, it has the disadvantage that a product of high purity cannot be obtained and the yield is low. US Pat. No. 3,296,308 discloses that thiophenol is reacted with monochloroacetic acid to produce phenylmercaptoacetic acid, which is then chlorinated to produce parachlorophenylmercaptoacetic acid, which is then oxidized and reduced to produce parachlorothiophenol. The manufacturing method is described. Although this method has the advantage of selectively obtaining parachlorothiophenol compared to the former,
It has the disadvantage that the process is particularly long, and it cannot be said to be an industrially advantageous method. US Pat. No. 3,326,981 describes a method for reducing parachlorobenzenesulfonyl chloride with zinc;
Chem. Ber., 99, 376 ('66) describes a method for reducing parachlorobenzenesulfonyl chloride with phosphorus. However, both methods have the disadvantage that the reducing agent is expensive and that a large amount of waste water containing zinc or phosphorus, which causes pollution, is produced. Zh.Org.Khim., 1975, 11(5), 1132 describes a method for obtaining parachlorothiophenol by reacting paradichlorobenzene and hydrogen sulfide at a high temperature of 580°C. However, the yield of parachlorothiophenol is low and a large amount of by-products are produced. The present invention involves halogenating diphenyl sulfide in a nonpolar solvent to produce 4,4'-dihalogenodiphenyl sulfide, and then reacting this with hydrogen sulfide at an elevated temperature. Parahalogenothiophenols are produced by the same method, but in previous literature it was thought that the halogen groups of halogenated aromatic compounds were dehalogenated by the action of hydrogen sulfide or sodium hydrogen sulfide at high temperatures. . For example, in U.S. Pat. No. 3,415,889, paradichlorobenzene or 1,2,4-trichlorobenzene is mixed with sodium sulfide in an autoclave at
Thiophenol is obtained by heating to 350℃. This is clearly paradichlorobenzene or 1,2,
This shows that the dehalogenation reaction of 4-trichlorobenzene is occurring. Also, Zh.Org.Khim.
, 1975, 11(5), 1132, the reaction between paradichlorobenzene and hydrogen sulfide requires a high temperature of 580°C, so dehalogenation of paradichlorobenzene or the painstakingly produced parachlorothiophenol occurs.
After all, the yield of parachlorothiophenol is considered to be extremely low. Japanese Patent Publication No. 45-5531 describes a method for producing thiophenol from diphenyl sulfide and hydrogen sulfide in a gas phase catalytic manner. However, nothing is described about the reaction between halogen-containing diphenyl sulfide and hydrogen sulfide, and the reaction of the present invention is not suggested in view of the above-mentioned dehalogenation relationship. The present inventors have conducted intensive research on the method for producing parahalogenothiophenol, and found that when diphenyl sulfide is halogenated in a nonpolar solvent, the halogenation occurs almost completely only at the 4,4' position. 4,4'-dihalogenodiphenyl sulfide is produced by halogenation and gas phase reaction of the obtained 4,4'-dihalogenodiphenyl sulfide with hydrogen sulfide at elevated temperature. The present invention was achieved by discovering that parahalogenothiophenol can be obtained in good yield by suppressing the dehalogenation of nyl sulfide. The characteristics of the present invention include that a product of high purity can be obtained, that the yield is high, that the process is simple, that it is a closed and pollution-free process, and that it is therefore economically advantageous. More specifically, when diphenyl sulfide is halogenated in a nonpolar solvent, halogenation occurs mostly at the 4,4' position, selectively producing 4,4'-dihalogenodiphenyl sulfide. Therefore, in the next step of reacting this with hydrogen sulfide, a highly pure product can be obtained with no by-products other than a small amount of thiophenol, such as orthohalogenothiophenol. On the other hand, the yield of 4,4'-dihalogenodiphenyl sulfide during halogenation of diphenyl sulfide is high, and in the next step of reacting 4,4'-dihalogenodiphenyl sulfide with hydrogen sulfide, it is necessary to There are almost no living organisms, and parahalogenothiophenol can be obtained in high yield by recycling unreacted 4,4'-dihalogenodiphenyl sulfide. Furthermore, in the process of halogenating diphenyl sulfide, a nearly stoichiometric amount of hydrogen halide is produced, which can be neutralized and rendered harmless after absorption with an alkali. By recycling surplus hydrogen sulfide in the process of reacting rufid with hydrogen sulfide, it has various characteristics such as not producing any waste liquid that causes pollution. Embodiments of the present invention will be described below. First, 4,4'-dihalogenodiphenyl sulfide is produced by dissolving diphenyl sulfide in a nonpolar solvent, adding a halogenation catalyst if necessary, and adding halogen. manufactured by Here, the non-polar solvent is a solvent with low polarity that does not react with halogen under the present reaction conditions, and includes aromatic hydrocarbons, aliphatic hydrocarbons, and halides thereof. Specifically, for example, benzene, chlorobenzene, orthochlorobenzene, pentane, hexane, heptane, octane, cyclohexane, methane dichloride, chloroform, carbon tetrachloride, ethane dichloride, trichloroethane, tetrachloroethane, trichlorene, perchlorene, etc. can be mentioned. When benzene or the like is used as a solvent, the reaction proceeds satisfactorily without adding a halogenation catalyst. On the other hand, if carbon tetrachloride is used as a solvent, the reaction will be slow unless a halogenated catalyst is added. Examples of halogenation catalysts include Friedel-Crafts type catalysts, such as iron chloride, aluminum chloride, tin chloride,
Titanium chloride, zinc chloride, etc. are effective. Also,
When adding halogen, add it gradually to avoid a sudden rise in temperature, and the appropriate temperature at this time is around room temperature.
The appropriate amount of halogen is 2 to 3 times the mole of diphenyl sulfide. After adding a predetermined amount of halogen, the reaction mixture is gently heated to complete the reaction. When chlorine is used as the halogen, the excess chlorine blown in at this time is expelled and recovered. On the other hand, when a polar solvent such as acetic acid or sulfuric acid is used, various by-products such as halides at positions other than the 4-position and diphenyl sulfide containing three or more halogens increase. The 4,4'-dihalogenodiphenyl sulfide thus obtained contains a small amount of diphenyl sulfide and 4-halogenodiphenyl sulfide, but is passed through the next step without any particular purification. It can be offered to In particular, when benzene or the like is used as a solvent, benzene itself is inert in the next step, so there is an advantage that the solution after the reaction can be supplied as a raw material for the next step.
4,4′-dihalogenodiphenyl sulfide has a melting point
Since it is a solid substance at room temperature around 100℃, it is very convenient to handle it as a solution such as benzene. Further, highly pure 4,4'-dihalogenodiphenyl sulfide can be obtained by distillation under reduced pressure or recrystallization from a solvent such as isopropanol. Next, a process of reacting 4,4'-dihalogenodiphenyl sulfide and hydrogen sulfide in a high temperature gas phase will be described. Although this reaction can proceed satisfactorily without a catalyst, it can be carried out at a lower temperature using a catalyst. That is, in the case of no catalyst, a temperature of 400 to 550°C is usually appropriate, although it depends on other reaction conditions.
In this case, the reaction hardly progresses below 400°C, and above 550°C dehalogenation reaction occurs, increasing the production of thiophenol and decreasing the yield of parahalogenothiophenol. In addition, when activated carbon, metal oxide, or metal sulfide is used, 200 to 450
℃ temperature is suitable. For example, when activated carbon is used as a catalyst, the reaction does not proceed at a reaction temperature of 200°C or lower;
Moreover, at temperatures above 450°C, dehalogenation reaction occurs, so the production of thiophenol increases, and the yield of parahalogenothiophenol decreases. In either case, it is preferable to carry out the reaction at a lower reaction temperature to increase the yield of parahalogenothiophenol per raw material, even if the rate of change of the raw material is sacrificed to some extent. The catalyst of the present invention includes activated carbon, metal oxide,
Metal sulfides, activated alumina, etc. can be used. There is no need to specifically explain activated carbon and activated alumina, but examples of metal oxides and metal sulfides include nickel oxide, cobalt oxide, molybdenum oxide,
These include iron oxide, chromium oxide, nickel sulfide, cobalt sulfide, molybdenum sulfide, iron sulfide, etc., and it may be more effective to use two or more of these in combination than to use them alone. It is rather common to use these metal oxides or metal sulfides supported on porous materials such as diatomaceous earth, alumina, silica, silica alumina, pumice, and activated carbon. Furthermore, the larger the molar ratio of hydrogen sulfide to 4,4'-dihalogenodiphenyl sulfide, the more 4,4'-
The yield of parahalogenothiophenol relative to dihalogenodiphenyl sulfide is increased. However, increasing this molar ratio too much is rather uneconomical, and the molar ratio must be such that at least the 4,4'-dihalogenodiphenyl sulfide remains sufficiently gasified at the reaction temperature. Yes, molar ratio is 1~
A range of 50 is preferred. In addition, when carrying out the present invention using a catalyst, the space velocity (the value obtained by dividing the amount of raw material gas by the catalyst volume) varies depending on other reaction conditions, but is 50~
A range of 1000 [1/Hr] is preferable. When a catalyst is not used, the above range calculated using the volume of the reaction tube in the predetermined temperature range is preferable. The reaction of 4,4'-dihalogenodiphenyl sulfide with hydrogen sulfide will stoichiometrically yield 2 moles of halogenothiophenol per mole of raw material, but some dehalogenation will occur. Therefore, the formation of thiophenol and trace amounts of diphenyl sulfide and 4'-halogenodiphenyl sulfide was observed. In addition, a small amount of diphenyl sulfide and 4,4'-dihalogenodiphenyl sulfide containing 4-halogenodiphenyl sulfide can be produced by halogenating diphenyl sulfide without particularly purifying the product. When used as raw materials, these by-products ultimately lead to the formation of thiophenol and diphenyl sulfide. These thiophenol and diphenyl sulfide are easily separated from parahalogenothiophenol by distillation. This by-produced thiophenol itself is a substance that has various uses, but on the other hand, this thiophenol can also be converted to the original diphenyl sulfide through a desulfurization reaction in a high-temperature gas phase. .
Furthermore, as mentioned above, 4,4'-dihalogenodiphenyl sulfide can be dissolved in a solvent inert to the reaction and supplied to the reactor as a solution. Examples of such solvents include benzene, chlorobenzene, and orthodichlorobenzene. In the present invention, diphenyl sulfide is first dissolved in a nonpolar solvent, and if necessary, in the presence of a small amount of halogenation catalyst, halogen gas is blown in or added dropwise while maintaining the temperature around room temperature. It will be implemented. After introducing a predetermined amount of halogen, the temperature of the reaction solution is gradually raised to complete the reaction.
Next, 4,4'-dihalogenodiphenyl sulfide purified by an appropriate method or, for example, this benzene solution and hydrogen sulfide are preheated to an elevated temperature by an appropriate method, and then a reactor is maintained at a predetermined temperature. lead to. If necessary, the inside of the reactor is filled with a porcelain ring or the like to improve gas dispersion, or the reactor is filled with the above-mentioned catalyst. The reaction can be carried out under either normal pressure or increased pressure, and when a catalyst is used, it can be carried out in either a fixed bed or a fluidized bed. However, since the reaction heat of this reaction is not so large, there is little advantage in carrying out this reaction in a fluidized bed. The product gas obtained from the reactor is cooled and separated into gas and liquid. If the above solvent is not used, unreacted raw materials will precipitate unless the temperature of the cooler is adjusted.
It may block the cooler. The reaction product condensed or solidified in the cooler is purified by a conventional method. For example, when the reaction product is distilled when a benzene solution of 4,4'-dichlorodiphenyl sulfide is used as a raw material, a small amount of thiophenol is distilled out under reduced pressure following the benzene solvent, and then a high-purity product is distilled out. Parachlorothiophenol is distilled out as a product. The residue contains a small amount of diphenyl sulfide 4-chlordiphenyl sulfide 4,
It consists of 4'-dichlorodiphenyl sulfide, which can be further distilled under reduced pressure to recover the raw material. On the other hand, hydrogen sulfide containing a small amount of hydrochloric acid gas can be recycled as is, or it can be washed with an aqueous sodium hydrogen sulfide solution to remove the hydrochloric acid gas and used again as a raw material. The present invention will be explained in more detail with reference to Examples below, but these are not intended to limit the scope of the present invention. Example 1 1 equipped with a stirrer, reflux condenser, and chlorine blowing pipe
57.9 g of diphenyl sulfide, 500 ml of carbon tetrachloride, and 0.12 g of anhydrous ferric chloride were placed in a flask, and while stirring thoroughly, 66.3 g of chlorine was blown into the flask over a period of 3 hours. Cool the flask in a water bath and reduce the contents to 20-25
It was maintained at ℃. A solid substance precipitated after a while after starting to blow chlorine gas, but this solid was dissolved when further chlorine gas was introduced. After about 2.5 hours, solid precipitated again. After blowing in chlorine gas, the temperature was gradually raised and kept at the reflux temperature of carbon tetrachloride for 30 minutes to complete the reaction. At this time, generation of excess chlorine was observed, and the reaction solution became homogeneous. Analysis of the reaction solution by gas chromatography revealed that 73.9 g of 4,4'-dichlorodiphenyl sulfide and 0.4 g of 4-chlordiphenyl sulfide were produced. Diphenyl sulfide was 0.3g. Calculating from this,
The yield of 4,4'-dichlorodiphenyl sulfide is
It was 93.2%. The amount of trichlordiphenyl sulfide produced was only a trace. Carbon tetrachloride was distilled off from this reaction solution, and when the solution was cooled, a solid was precipitated. The crystals were washed twice with 20 ml of isopropanol on a dowel to give 48.3 g of a white solid. This substance had a melting point of 95°C, and gas chromatograph analysis revealed that it was diphenyl sulfide.
It was found that 4-chlordiphenyl sulfide was not contained at all. Next, a 25 weight percent benzene solution of 4,4'-dichlorodiphenyl sulfide thus obtained was mixed with 36 g/Hr and hydrogen sulfide 150 c.c./min (molar ratio
11.5) was supplied to a preheater consisting of a stainless steel pipe with an inner diameter of 40 m/m and a length of 200 m/m filled with a porcelain ring with an outer diameter of 5 m/m and a height of 5 m/m. The preheater is heated with an electric furnace, and the raw material gas reaches 400℃.
I adjusted it so that The raw material gas leaving the preheater is heated to a 200c.c. porcelain ring with an outer diameter of 5m/m and a height of 5m/m.
was introduced into a reactor consisting of a stainless steel pipe with an inner diameter of 40 m/m and a length of 500 m/m. The reactor was controlled by a band heater to maintain the internal porcelain ring at 500°C. The reaction gas discharged from the reactor was cooled to about 20°C, and the reaction liquid was collected. When the reaction solution was analyzed by gas chromatography, the composition of the reaction solution excluding benzene was parachlorothiophenol 16.0Wt%, thiophenol 1.2Wt%,
4,4′-dichlordiphenyl sulfide 82.2Wt%
There were only traces of diphenyl sulfide and 4-chlordiphenyl sulfide. In addition, the reactor
When maintained at 380℃, the composition is parachlorothiophenol 0.1Wt%, thiophenol 0.1Wt%,
4,4′-dichlordiphenyl sulfide 99.7Wt%
It was hot. Example 2 36 g/Hr of the 25 Wt% benzene solution of 4,4'-dichlorodiphenyl sulfide obtained in Example 1 and 150 c.c./mm of hydrogen sulfide (molar ratio 11.5) were preheated in the same manner as in Example 1. The temperature of the raw material gas was adjusted to 270°C. The raw material gas exiting the preheater was supplied to the same reactor as in Example 1. Inside the reactor is 4m/mφ×
6m/m cylindrical activated carbon (Shirasagi Charcoal CX-4/
6) was filled at 200 c.c. (space velocity 88 (1/Hr)) and the temperature of the catalyst layer was maintained at 300°C. The gas at the outlet of the reactor was cooled to about 20°C, and after the flow reached a steady state, the reaction solution was analyzed, and it was found that parachlorothiophenol 23.5Wt%, thiophenol 3.1Wt%, and 4-chlordiphenyls. 1.1 Wt% of sulfide and 70.9 Wt% of 4,4'-dichlorodiphenyl sulfide. In addition, when the temperature of the reactor was maintained at 460℃, parachlorothiophenol 5.1Wt%, thiophenol 46.5Wt%, diphenyl sulfide 4.8Wt%, 4
- Chlordiphenyl sulfide 1.2Wt%, 4,
The content of 4′-dichlordiphenyl sulfide was 38.1 Wt%. Examples 3 to 8 A 25 Wt% benzene solution of 4,4'-dichlorodiphenyl sulfide obtained in Example 1 was used in the same gas phase reactor as in Example 2, with various catalysts and reaction conditions. I changed the reaction. Table 1 lists the results of gas chromatograph analysis of the reaction solution.

[Table] Example 9 Put 57.9 g of diphenyl sulfide and 440 g of benzene into the same chlorination equipment as in Example 1, and add 55 g of chlorine gas.
g over 2.5 hours. Increase the reaction temperature to 20
Maintain the temperature at ~24℃ and increase the temperature to 80℃ after chlorine gas blowing.
It was maintained for a minute. Analysis of the obtained benzene solution by gas chromatography revealed that 65.9 g of 4,4'-dichlorodiphenyl sulfide and 8.5 g of 4-chlordiphenyl sulfide were produced. Diphenyl sulfide was 0.8g. Trichlordiphenyl sulfide was not detected. The yield of 4,4'-dichlorodiphenyl sulfide was 83.0%. This benzene solution 80g/Hr and hydrogen sulfide 150c.c./
min was subjected to a gas phase reaction in the same manner as in Example 2. (However, molar ratio 10.0, space velocity 148 [1/Hr]) When analyzed by gas chromatography, parachlorthiophenol 19.2Wt%, thiophenol 5.0Wt%
%,4,4'-dichlorodiphenyl sulfide
It was 73.0Wt%. Example 10 55.8 g of diphenyl sulfide, carbon tetrachloride in a flask equipped with a stirrer, reflux condenser, and a dropping funnel.
600 ml was charged, and 101 g of bromine was added dropwise over 2 hours. The reaction temperature was maintained at 20℃, and after the dropwise addition it was heated to 77℃ for 30
The reaction was completed by fractional treatment. When the reaction solution was analyzed by gas chromatography, no by-products were detected except for 96.3 g of 4,4'-dibromidiphenyl sulfide and a small amount of 4-bromidiphenyl sulfide. . The yield of 4,4'-dibromidiphenyl sulfide was 93.3%. Carbon tetrachloride was distilled off from the reaction solution, and the precipitated solid was washed with isopropanol to obtain 4,
4′-dibrom diphenyl sulfide was obtained. Next, add 40g/Hr of a 25Wt% benzene solution of this 4,4'-dibromodiphenyl sulfide and hydrogen sulfide.
A gas phase reaction was carried out in the same manner as in Example 2 at 150 c.c./min. (However, molar ratio 13.8, space velocity 91 [1/
[Hr]] Analysis by gas chromatography revealed that 25.2 Wt% of para-bromthiophenol, 2.9 Wt% of thiophenol, and 70.2 Wt% of 4,4'-dibromodiphenyl sulfide were produced. Comparative example Diphenyl sulfide was added to the same equipment as in Example 1.
55.8 g of acetic acid, 150 ml of acetic acid, and 0.12 g of ferric chloride anhydride were added, and 55 g of chlorine gas was blown in over 2.5 hours. The reaction temperature was maintained at 60°C. Analysis by gas chromatography revealed that 20.8 g of 4,4'-dichlorodiphenyl sulfide had been produced, as well as large amounts of three other by-products. It was found from the gas mass spectrum that these were trichlorides and chlorides at positions other than the 4-position.

Claims (1)

[Claims] 1. 4,4'-halogenodiphenyl sulfide is produced by halogenating diphenyl sulfide in a nonpolar solvent, and sulfurized with 4,4'-dihalogenodiphenyl sulfide. Molar ratio of hydrogen: 1:10 to 30, temperature
A method for producing parahalogenothiophenol, which comprises reacting in a gas phase under conditions of 200 to 550°C. 2. The method according to claim 1, wherein the nonpolar solvent is benzene. 3. The method according to claim 1, wherein the nonpolar solvent is chlorobenzene. 4. The method according to claim 1, wherein the nonpolar solvent is carbon tetrachloride. 5. The method according to claim 1, wherein diphenyl sulfide is halogenated in the presence of a halogenation catalyst. 6. The method according to claim 5, wherein the halogenation catalyst is ferric chloride. 7. The method according to claim 1, wherein 4,4'-dihalogenodiphenyl sulfide and hydrogen sulfide are reacted in a gas phase catalytic manner in the presence of a catalyst. 8. The method according to claim 7, wherein the gas phase catalytic reaction is carried out while maintaining the temperature at 200°C to 350°C. 9. The method according to claim 7, wherein the catalyst is activated carbon. 10. The method according to claim 7, wherein the catalyst is nickel sulfide. 11. The method according to claim 7, wherein the catalyst is alumina. 12. The method according to claim 7, wherein the catalyst is a combination of cobalt oxide, molybdenum, and alumina. 13. The method according to claim 7, wherein the catalyst is a combination of molybdenum oxide and alumina. 14. The method according to claim 1, wherein the reaction between 4,4'-dihalogenodiphenyl sulfide and hydrogen sulfide is carried out at a space velocity of 50 to 1000/Hr. 15 Claim 1 states that a non-polar solvent solution of 4,4'-dihalogenodiphenyl sulfide obtained by halogenating diphenyl sulfide in a non-polar solvent is directly used for the reaction with hydrogen sulfide. the method of.