阅读说明：本技术 一种防焦剂n-苯基-n-三氯甲硫基苯磺酰胺的环保型合成方法 (Environment-friendly synthetic method of scorch retarder N-phenyl-N-trichloromethylthio benzenesulfonamide ) 是由 吕寻伟 马德龙 王庆振 吴彩英 左秀娟 于 2020-05-27 设计创作，主要内容包括：本发明公开了一种防焦剂N-苯基-N-三氯甲硫基苯磺酰胺的环保型合成方法,步骤为：控制温度,向苯胺、碱、TBAB和水的混合溶液中滴加苯磺酰氯,然后分段升温制备中间体。反应后用有机溶剂萃取中间体,含有中间体的有机母液与碱、TBAB和水混合,控制温度向此混合溶液中滴加全氯甲硫醇,然后分段升温得到最终产品。本发明在中间体和产品合成过程中的采用分段升温的方式,同时结合碱和相转移催化剂,提高了反应转化率,降低了副反应的发生,所得产物外观为纯白色,纯度高,品质稳定,填补了国内的技术空白,废水COD和总氮含量也急剧降低,废水中全氯甲硫醇的强烈刺激性的气味大大降低,使废水处理难度降低,达到了清洁生产的效果。(The invention discloses an environment-friendly synthesis method of an anti-scorching agent N-phenyl-N-trichloromethylthio benzene sulfonamide, which comprises the following steps: and (3) controlling the temperature, dropwise adding benzene sulfonyl chloride into a mixed solution of aniline, alkali, TBAB and water, and then heating in sections to prepare an intermediate. Extracting the intermediate by using an organic solvent after the reaction, mixing the organic mother liquor containing the intermediate with alkali, TBAB and water, controlling the temperature, dropwise adding perchloromethylmercaptan into the mixed solution, and then heating in sections to obtain the final product. The invention adopts a sectional heating mode in the synthesis process of the intermediate and the product, combines alkali and a phase transfer catalyst, improves the reaction conversion rate, reduces the occurrence of side reaction, ensures that the obtained product has pure white appearance, high purity and stable quality, fills the technical blank in China, sharply reduces the COD and the total nitrogen content of the wastewater, greatly reduces the strong pungent smell of the perchloromethylmercaptan in the wastewater, reduces the difficulty of wastewater treatment, and achieves the effect of clean production.)

1. an environment-friendly synthesis method of an anti-scorching agent N-phenyl-N-trichloromethylthio benzene sulfonamide is characterized by comprising the following steps:

(1) preparing a mixed solution of aniline, alkali, a phase transfer catalyst and water;

(2) cooling the mixed solution to be less than or equal to-15 ℃, and then dropwise adding benzene sulfonyl chloride at the temperature;

(3) after the benzene sulfonyl chloride is added, firstly heating to 15-25 ℃ for reaction for 1-2h, and then heating to 70-75 ℃ for reaction until the pH value is neutral;

(4) transferring the reaction liquid obtained in the step (3) to an extraction kettle, adding an organic solvent, heating to 80-120 ℃ until the N-phenyl benzene sulfonamide precipitate is completely dissolved, and standing for layering to obtain an organic mother liquid containing the N-phenyl benzene sulfonamide;

(5) mixing the organic mother liquor containing the N-phenyl benzene sulfonamide obtained in the step (4) with alkali, a phase transfer catalyst and water to obtain a mixed solution;

(6) cooling the mixed solution obtained in the step (5) to be less than or equal to 0 ℃, and then dropwise adding perchloromethylmercaptan at the temperature;

(7) after adding the complete chloromethanethiol, heating to 40-50 ℃ for reaction for 1-2h, then continuing heating to 70-80 ℃ for reaction for 1.5-2.5h, and then treating the reaction liquid to obtain the anti-scorching agent N-phenyl-N-trichloromethylthiobenzene sulfonamide.

2. The environment-friendly synthesis method according to claim 1, wherein: in the steps (1) and (5), the phase transfer catalyst is TBAB; in the step (4), the organic solvent is solvent oil or/and alkane.

3. The environment-friendly synthesis method according to claim 1, wherein: in the step (4), the organic solvent is 120# solvent oil or a mixture of 120# solvent oil and n-hexane.

4. An environmentally friendly synthesis method according to claim 1, 2 or 3, wherein: in the step (4), the mass ratio of the organic solvent to the N-phenyl benzene sulfonamide is 3-5: 1.

5. An environmentally friendly synthesis method according to claim 1, 2 or 3, wherein: in the steps (1) and (2), the molar ratio of aniline to alkali is 1: 1.0-1.5, wherein the molar ratio of aniline to benzenesulfonyl chloride is 1: 1.0-1.5, wherein the dosage of the phase transfer catalyst is 2-4% of the mass of the aniline.

6. An environmentally friendly synthesis method according to claim 1, 2 or 3, wherein: in the steps (5) and (6), the molar ratio of the N-phenyl benzene sulfonamide to the alkali is 1: 1-1.5, wherein the dosage of the transfer catalyst is 2-4% of the mass of aniline, and the molar ratio of N-phenyl benzene sulfonamide to perchloromethylmercaptan is 1: 1.0 to 1.5.

7. The environment-friendly synthesis method according to claim 1, wherein: in the step (2), the temperature is reduced to-10 to-15 ℃; in the step (6), the temperature is reduced to-5-0 ℃.

8. The environment-friendly synthesis method according to claim 1 or 7, wherein: in the step (2), the dripping time of the benzene sulfonyl chloride is controlled to be 1-2 h; in the step (6), the dripping time of the perchloromethylmercaptan is controlled to be 0.5-1 h.

9. The environment-friendly synthesis method according to claim 1, wherein: in the steps (1) and (5), the base is an organic base or an inorganic base, preferably at least one of sodium hydroxide, potassium hydroxide, triethylamine and pyridine.

10. An environmentally friendly synthesis method according to claim 1, 2 or 3, wherein: in the step (7), the reaction liquid is heated to 90-110 ℃ for extraction, then the mixture is stood for layering, and the organic phase is cooled and crystallized to obtain the anti-coking agent N-phenyl-N-trichloromethylthio benzenesulfonamide.

Technical Field

The invention relates to a synthetic method of an anti-coking agent N-phenyl-N-trichloromethylthio benzene sulfonamide, in particular to a synthetic method of an environment-friendly and continuous anti-coking agent N-phenyl-N-trichloromethylthio benzene sulfonamide, and belongs to the technical field of organic synthesis.

Background

The scorching phenomenon is a phenomenon in which the compound undergoes premature vulcanization crosslinking under the action of heat during storage and processing, and loses fluidity and reworkability. Scorching of rubber compounds is one of the most common problems in rubber processing, and in particular, scorching is more easily caused by compounding agents (such as reinforcing resin, m-methyl white system adhesive, fine particle carbon black and the like) which are used for causing scorching in the modern high-temperature, rapid and efficient processing technology. Scorch can be solved by adjusting the vulcanization system, but requires complicated equipment. It is widely believed that the use of scorch retarders is the simplest and most practical way to prevent scorching. Therefore, the rubber scorch retarder becomes an important auxiliary agent for the safety of rubber processing.

There are three classes of scorch retarders: namely organic acids, nitroso compounds and sulfenamides. Organic acids such as salicylic acid, benzoic acid phthalate and phthalic anhydride have weak anti-scorching capability, high selectivity to accelerators, can reduce vulcanization speed and performance of vulcanized rubber, and has irritation to skin, wherein phthalic anhydride is more commonly used, can be used for light-colored rubber products, is only effective on alkaline accelerators DPG and MBT accelerators, and is not effective on NOBS and TMTD. Nitroso compounds such as N-nitrosodiphenylamine, N-nitroso-phenyl-beta-naphthylamine and N-nitroso-2, 2, 4-trimethyl-1, 2-dihydroquinoline polymer, wherein N-Nitrosodiphenylamine (NDPA) is commonly used, and the scorch retarder has better scorch preventing effect on thiazole and sulfenamide accelerators, different from organic acid. The sulfenamide scorch retarder is a series of compounds containing S-N bond, and scorch retarders with different performances can be obtained according to different R groups, wherein a commercial scorch retarder E (namely N-phenyl-N-trichloromethylthio benzene sulfonamide, also known as N-phenyl-N [ (trichloromethyl) thio ] benzene sulfonamide), PVI or CTP is the most excellent scorch retarder. At present, the scorch retarder CTP is commonly used in China, but under the same coordination system, the physical properties such as tensile strength, compression set and the like are partially reduced due to the excessive CTP. And the scorch retarder E has better scorch retarding effect than the scorch retarder CTP. In the EPDM rubber compound, the scorch retarder E has excellent scorch retarding performance, has no adverse effect on the vulcanization characteristic and the physical property of the rubber compound, and even has the function similar to that of an accelerator to promote the vulcanization of rubber. In addition, the anti-scorching agent E has good storage stability and operability, meets the production safety and sanitation requirements, and better meets the requirements of an ideal anti-scorching agent.

The scorch retarder E is not developed in China, and special sizing materials can only be imported. The development and research of the novel high-efficiency anti-coking agent E can fill the vacancy in the domestic technical aspect and improve the product diversity and the international competitiveness.

Disclosure of Invention

Aiming at the technical blank existing in the prior synthesis of the scorch retarder E, the invention provides an environment-friendly synthesis method of the scorch retarder N-phenyl-N-trichloromethylthio benzenesulfonamide, which has the advantages of environmental protection, less three-waste discharge, high raw material utilization rate, high conversion rate, high purity of the obtained product, good yield and capability of making up the domestic blank.

The specific technical scheme of the invention is as follows:

an environment-friendly synthesis method of an anti-scorching agent N-phenyl-N-trichloromethylthio benzene sulfonamide comprises the following steps:

(1) preparing a mixed solution of aniline, alkali, a phase transfer catalyst and water;

(2) cooling the mixed solution to be less than or equal to-15 ℃, and then dropwise adding benzene sulfonyl chloride at the temperature;

(3) after the benzene sulfonyl chloride is added, firstly heating to 15-25 ℃ for reaction for 1-2h, and then heating to 70-75 ℃ for reaction until the pH value is neutral;

(4) transferring the reaction liquid obtained in the step (3) to an extraction kettle, adding an organic solvent, heating to 80-120 ℃ until the N-phenyl benzene sulfonamide precipitate is completely dissolved, and standing for layering to obtain an organic mother liquid containing N-phenyl benzene sulfonamide;

(5) mixing the organic mother liquor containing the N-phenyl benzene sulfonamide obtained in the step (4) with alkali, a phase transfer catalyst and water to obtain a mixed solution;

(6) cooling the mixed solution obtained in the step (5) to be less than or equal to 0 ℃, and then dropwise adding perchloromethylmercaptan at the temperature;

(7) after adding the complete chloromethanethiol, heating to 40-50 ℃ for reaction for 1-2h, then continuing heating to 70-80 ℃ for reaction for 1.5-2.5h, and then treating the reaction liquid to obtain the anti-scorching agent N-phenyl-N-trichloromethylthiobenzene sulfonamide.

Further, in the steps (1) and (5), alkali is added to eliminate acid formed in the reaction, so that the reaction is continuously kept in a forward reaction, and the reaction rate and the yield are improved. The base may be an organic base or an inorganic base, for example, at least one of sodium hydroxide, potassium hydroxide, triethylamine, pyridine, and the like, and sodium hydroxide is preferable from the viewpoint of cost. The base may be added in solid form or in liquid form.

Further, in the step (1), the molar ratio of aniline to alkali is 1: 1.0 to 1.5; in the step (5), the molar ratio of the N-phenyl benzene sulfonamide to the alkali is 1: 1-1.5, and a slight excess of base.

Furthermore, in the steps (1) and (5), the adding sequence of the raw materials is random and has no special requirement. For example, each raw material may be added directly as a solid, or may be added as a solution, and may be added at once, or may be added in portions or continuously. The water in the step (1) has the function of enabling the reaction to be carried out uniformly, providing a reaction environment, and having no special requirement on the dosage, and the water can be added in a pure water form or a raw material water solution form as long as the normal reaction is ensured. In the step (5), the water and the organic solvent are used together to ensure that the reaction raw materials are fully dissolved so as to be more beneficial to the reaction, the dosage of the water can be randomly selected on the basis, and the water can be added in the form of pure water or in the form of raw material aqueous solution.

Furthermore, in the steps (1) and (5), a phase transfer catalyst is added, so that the reaction rate is further improved, the reaction time is shortened, and the production efficiency is improved. The phase transfer catalyst may be one that is reported in the prior art to facilitate feedstock conversion, such as TBAB. The dosage of the phase transfer catalyst in the steps (1) and (5) is 2-4% of the mass of the aniline.

Further, in the step (2), the molar ratio of the aniline to the benzene sulfonyl chloride is 1: 1.0 to 1.5, preferably 1: 1.05-1.10, the dosage of aniline and benzene sulfonyl chloride is close to the theoretical molar ratio, and the utilization rate of raw materials is higher.

Further, in the step (2), the temperature of the mixed solution is preferably reduced to-10 to-15 ℃, and then benzene sulfonyl chloride is dropwise added, wherein the dropwise adding time of the benzene sulfonyl chloride is controlled to be 1-2 hours.

Furthermore, in the step (3), after the dropwise addition of the benzenesulfonyl chloride is finished, two-stage heating is adopted for reaction, so that better reaction is facilitated, and the occurrence of side reactions is reduced.

Further, in the step (4), the organic solvent may be one or more of mineral spirit, alkane, etc., such as one or more of n-hexane, mineral spirit, etc. The invention reduces the dosage of benzene sulfonyl chloride, reduces side reactions and greatly improves the yield and the purity of the intermediate N-phenyl sulfonamide through the use of alkali and a phase transfer catalyst and the adjustment of reaction temperature, so that the intermediate is used for the next reaction after being extracted by an organic solvent. Compared with the direct filtration and extraction of the intermediate solid, the operation greatly reduces the waste water generated by washing, saves the filtration and drying of the intermediate, avoids the contact between workers and the intermediate material, directly enters the next synthesis, improves the production efficiency and the operation simplicity, reduces the waste water amount and the COD and nitrogen content of the waste water, achieves the effect of clean production, and is more simple and convenient to operate.

Furthermore, when the organic solvent is alkane, the alkane can dissolve other impurities while extracting the target product, thereby reducing the purity and yield of the product. When the organic solvent is solvent oil, the target product can be extracted in an extraction mode, and the obtained product has high purity and yield and has an effect superior to that of alkane. More surprisingly, when the solvent oil is mixed with the alkane, the purity and the yield of the product are further improved, and the effect is unexpected, and the mass ratio of the solvent oil to the alkane is 3-5: 1.

Preferably, the organic solvent is solvent oil or a mixture of solvent oil and n-hexane, and the solvent oil can be No. 120 solvent oil and the like.

Further, in the step (4), the mass ratio of the organic solvent to the N-phenyl benzene sulfonamide is 3-5: 1.

Further, in the step (4), after the organic solvent is added, the temperature can be raised for stirring to accelerate the dissolution of the intermediate, and then the mixture is kept stand for layering.

Further, in the step (6), the molar ratio of the N-phenyl benzene sulfonamide to the perchloromethylmercaptan is 1: 1.0 to 1.5.

Further, in the step (6), preferably, the temperature of the mixed solution is reduced to-5-0 ℃, and then perchloromethylmercaptan is dripped, wherein the dripping time of the perchloromethylmercaptan is controlled to be 0.5-1 h.

Further, in the step (7), after the complete chloromethanethiol is added, the temperature is raised to 40-50 ℃ for reaction, and then the temperature is raised to 70-80 ℃ for reaction for 1.5-2.5h, so that the sectional reaction is favorable for forming reaction products, and the side reaction is well reduced.

Further, in the step (7), the reaction liquid is heated to 90-110 ℃ until the precipitate is completely dissolved, then the reaction liquid is extracted for about 20min at the temperature, then the reaction liquid is kept stand for layering, the obtained organic phase is cooled and crystallized to obtain a product, and the crystallization temperature is controlled below-5 ℃.

The invention has the following beneficial effects:

1. cheap and easily-obtained alkali is used as a catalyst and matched with a phase transfer catalyst to catalytically synthesize the N-phenyl benzene sulfonamide and the N-phenyl-N-trichloromethylthio benzene sulfonamide, the alkali consumes hydrogen chloride generated by the reaction, and the phase transfer catalyst improves the reaction efficiency, so that the reaction is continuously kept in a forward reaction, the reaction time is greatly shortened, and the production efficiency and the yield are improved.

2. The temperature control in the synthesis process of the N-phenyl benzene sulfonamide is improved, and simultaneously, the alkali and the phase transfer catalyst are combined, so that the reaction conversion rate is improved, the side reaction is reduced, the dosage of benzene sulfonyl chloride is reduced, and the reaction raw materials are close to 1:1 to a greater extent.

3. The purity of the intermediate is greatly improved, the intermediate is extracted by an organic solvent and then directly enters the next step, the filtering and drying of the intermediate are omitted, the contact between workers and the intermediate material is avoided, the production efficiency is improved, the COD (chemical oxygen demand) and the total nitrogen content of the wastewater are sharply reduced, the smell of benzene sulfonyl chloride in the wastewater is greatly reduced, the difficulty in treating the intermediate mother liquor is reduced, and the effect of clean production is achieved.

3. The reaction conversion rate of the N-phenyl-N-trichloromethylthiobenzene sulfonamide synthesis section is high, the dosage of perchloromethylmercaptan is reduced, and the reaction raw materials are close to 1:1 to a greater extent. The obtained product is pure white in appearance, high in purity and stable in quality, and fills the domestic technical blank. The COD and the total nitrogen content of the wastewater are also sharply reduced, and the strongly irritant odor of the perchloromethylmercaptan in the wastewater is greatly reduced, so that the wastewater treatment difficulty is reduced, and the effect of clean production is achieved.

4. The organic solvent used in the invention can be recycled, and the method has less waste water and is beneficial to environmental protection. When the preferred organic solvent is adopted, the product purity is more than 97%, and the yield is more than 91%.

Detailed Description

The technical scheme of the invention is more clearly described by combining the embodiment of the invention. The following examples are only a part of the present invention, and not all examples. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The raw materials used in the following examples are all commercial conventional industrial chemicals.

In the following examples, the product yield is based on aniline, yield = actual mass of product/theoretical mass of product. The product purity was determined by HPLC method. COD in the mother liquor is detected by a potassium dichromate method, ammonia nitrogen is detected by a nano reagent spectrophotometry method, and total nitrogen is detected by an alkaline potassium persulfate digestion ultraviolet photometry method.