Continuous synthesis device of paratoluensulfonyl chloride and synthesis method thereof

Abstract

The invention relates to a continuous synthesis device of paratoluensulfonyl chloride and a synthesis method thereof. The synthesis method specifically comprises the following steps: (1) mixing chlorosulfonic acid, a catalyst and an organic solvent which are added at a time in a first static mixer to obtain a mixed solution A, and respectively pumping the mixed solution A and toluene into a first microreactor for reaction to obtain a reaction solution; (2) discharging the reaction liquid from an outlet of the first micro-reactor, separating out a liquid phase, respectively pumping the liquid phase, secondarily added chlorosulfonic acid and a mixed solution B in a second static mixer into a second micro-reactor, mixing, and reacting in the second micro-reactor to obtain a secondary reaction mixture; and (3) discharging the secondary reaction mixture from the second microreactor, separating out middle layer freezing crystals, filtering, and washing to obtain paratoluensulfonyl chloride. According to the synthesis method, the reaction temperature, the reaction time and the material ratio are accurately controlled, the production efficiency of paratoluensulfonyl chloride is greatly improved, and the synthesis method is green, safe and environmentally friendly.

Description

Technical Field

[0001] The invention relates to the technical field of fine chemical intermediate preparation, and in particular to a continuous synthesis device and a synthesis method of p-toluenesulfonyl chloride. Background Art

[0002] p-Toluenesulfonyl chloride (C 7 H 7 C1O 2 S) is an important fine chemical product. The product is white flaky crystals and is widely used in dye, medicine and pesticide industries. The synthesis of p-toluenesulfonyl chloride has the following synthetic routes according to different raw materials: ① p-toluenesulfonic acid, chlorine and S 2 Cl 2 As raw materials; ② mercaptan, KNO 3 and S 2 Cl 2 as raw material; ③ using p-toluenesulfonamide as raw material; ④ using toluene, chlorosulfonic acid and ammonium chloride as raw materials; ⑤ using toluene and chlorosulfonic acid as raw materials, N,N-dimethylacetamide or triethylamine as catalyst; ⑥ using toluene, chlorosulfonic acid and thionyl chloride as raw materials, using aminosulfonic acid as catalyst, etc.

[0003] Among the above synthetic routes, ④, ⑤, and ⑥ synthetic routes are all tosylation methods, among which the tosylation method with toluene and chlorosulfonic acid as the main raw materials is the most commonly used synthetic route. However, this synthetic route has a high reaction temperature and low production efficiency. It is also accompanied by the generation of a large amount of dilute sulfuric acid waste liquid and a large amount of hydrogen chloride gas, which seriously corrodes the equipment and pollutes the environment. It is impossible to accurately control the reaction process, and the yield needs to be improved. The above-mentioned ④ synthetic route is now mostly used for production in China, but the current process has a low yield, produces a large amount of acidic wastewater, and causes pollution. Therefore, it is of great social and economic significance to improve the yield of toluene chlorosulfonation reaction, reduce environmental pollution, and reduce production costs.

[0004] For this reason, production improvements have been carried out at home and abroad to reduce environmental pollution in the production process and improve its yield. Xu Yun, Wang Hongliang, etc. (Zhejiang Chemical Industry [J], 2003 (10): 10-11) used toluene as the starting material, carbon tetrachloride as the diluent, selected a composite catalyst, and chlorosulfonic acid to carry out chlorination reaction to synthesize p-toluenesulfonyl chloride, and adopted a new process of solvent direct crystallization purification and separation to obtain p-toluenesulfonyl chloride with a purity of 98% and a product yield of more than 88%. Chen Zhongxiu, Jiang Linwei, etc. used toluene, oxysulfonic acid, and phosphorus oxychloride as raw materials, and the p-toluenesulfonyl chloride yield was 85.41%, and the acid wastewater was reduced by more than 70% compared with the original process (Journal of Chemical Engineering of Colleges and Universities, 2004, 18 (2): 254-257). The process or production system disclosed in the above documents can only be improved on the basis of the traditional process, without substantial technical progress.

[0005] CN103588683A discloses a synthesis process of p-toluenesulfonyl chloride, and the yield of p-toluenesulfonyl chloride is as high as 99.87%, but the raw materials used are still complex, the raw material cost is high, and the problem of large waste acid production is not solved. CN201520995039 reports a production system of p-toluenesulfonyl chloride, including a sulfonation reactor, a decomposition reactor and a product post-processing system connected in sequence. This reactor series connection method does not solve the control problem, continuity problem, yield problem and "waste acid" problem in the production process, and it is even more impossible to achieve automation.

[0006] CN113277965A discloses a method for continuously synthesizing p-toluenesulfonyl chloride using a microchannel reactor. The material is directly fed into the microchannel reactor for reaction. The maximum crude product yield is as high as 95.12%. At the same time, continuous production is achieved and the output of waste acid can be greatly reduced. CN113582883A discloses a method for continuously synthesizing p-toluenesulfonyl chloride. Toluene, sulfur trioxide, chlorosulfonic acid, organic bases, solvents, and inhibitors are used as raw materials and two microreactors are used for series reaction. None of the above patents separate the sulfonation and chlorination reactions: CN113277965A has special requirements for the microreactor used, and the reaction process of CN113582883A must be carried out at low temperature. The method uses complex materials and uses SO that is easy to crystallize. 3 ; All of these increase the difficulty of operation and are difficult to promote in actual industrial production. CN101195593 discloses a method of sulfonation using sulfur trioxide and diluent alkylbenzene, but SO 3 It is still very difficult to promote it in actual industrial production, and the tubular reactor used is difficult to achieve precise control due to its own structural characteristics, and the pollution problem has not been effectively solved.

[0007] Although there are many problems with the toluenesulfonyl process using toluene and chlorosulfonic acid as the main raw materials, most domestic manufacturers still adopt this process route to produce p-toluenesulfonyl chloride because of its advantages such as fewer operating steps and short reaction cycle. However, excessive use of chlorosulfonic acid, as well as the large amount of hydrogen chloride gas and dilute sulfuric acid produced during the reaction, seriously corrode the equipment, the difficulty and cost of treatment are high, the environment is polluted, and the product yield is low, which are all problems that need to be solved urgently. Summary of the invention

[0008] In order to solve the above technical problems, the purpose of the present invention is to provide a continuous synthesis device and a synthesis method of p-toluenesulfonyl chloride. The present invention can achieve accurate control of reaction temperature, reaction time and reaction material ratio, greatly improve the production efficiency of p-toluenesulfonyl chloride, and is green, safe and environmentally friendly.

[0009] The technical solution of the present invention to solve the above technical problems is as follows:

[0010] The first object of the present invention is to provide a continuous synthesis device for toluenesulfonyl chloride, the synthesis device comprising a first static mixer, a toluene storage tank, a first microreactor, a first gas-liquid two-phase separator, a first falling film absorber, a second microreactor, a chlorosulfonic acid storage tank, a second microreactor, a second gas-liquid two-phase separator, a sulfuric acid storage tank, a freezing crystallizer, a centrifuge, a first metering pump, a second metering pump, a third metering pump, a fourth metering pump, a fifth metering pump, a sixth metering pump, a first liquid inlet pipe, a second liquid inlet pipe, a third liquid inlet pipe, a fourth liquid inlet pipe, a fifth liquid inlet pipe, a first connecting pipe, a second connecting pipe, a third connecting pipe, a fourth connecting pipe, a fifth connecting pipe, and an absorption pipe;

[0011] The first static mixer is connected to the inlet of the first microreactor via the first liquid inlet pipe, and the first liquid inlet pipe is provided with the first metering pump; the toluene storage tank is connected to the inlet of the first microreactor via the second liquid inlet pipe, and the second liquid inlet pipe is provided with the second metering pump; the first microreactor is connected to the first gas-liquid two-phase separator via the first connecting pipe;

[0012] The first gas-liquid two-phase separator is provided with two outlets, the first outlet of the first gas-liquid two-phase separator is connected to the first falling film absorber through the absorption pipe; the second outlet of the first gas-liquid two-phase separator is connected to the inlet of the second microreactor through the third liquid inlet pipe; the third liquid inlet pipe is provided with the third metering pump;

[0013] The chlorosulfonic acid storage tank is connected to the inlet of the second microreactor via the fourth liquid inlet pipe, and the fourth liquid inlet pipe is provided with the fourth metering pump; the second static mixer is connected to the second microreactor via the fifth liquid inlet pipe, and the fifth liquid inlet pipe is provided with the fifth metering pump;

[0014] The outlet of the second microreactor is connected to the second gas-liquid two-phase separator through a second connecting pipe; the second gas-liquid two-phase separator is provided with three outlets, the first outlet of the second gas-liquid two-phase separator is connected to the second falling film absorber; the second outlet of the second gas-liquid two-phase separator is connected to the inlet of the sulfuric acid storage tank through the fourth connecting pipe, and the sixth metering pump is arranged on the fourth connecting pipe; the third outlet of the second gas-liquid two-phase separator is connected to the freezing crystallizer through the third connecting pipe, and the freezing crystallizer is connected to the centrifuge through the third connecting pipe, and the centrifuge is connected to the second static mixer through the fifth connecting pipe.

[0015] A second object of the present invention is to provide a continuous synthesis method of tosyl chloride, which is as follows:

[0016] (1) mixing the chlorosulfonic acid, catalyst, and organic solvent added once in a first static mixer to obtain a mixed solution A, and pumping the mixed solution A and toluene into a first microreactor to react to obtain a reaction solution;

[0017] (2) discharging the reaction liquid from the outlet of the first microreactor and separating the liquid phase, and pumping the liquid phase, the chlorosulfonic acid added for the second time, and the mixed liquid B in the second static mixer into the second microreactor for mixing, and reacting in the second microreactor to obtain a secondary reaction mixture;

[0018] (3) discharging the secondary reaction mixture from the second microreactor and separating the intermediate layer of frozen crystals, filtering and washing to obtain p-toluenesulfonyl chloride.

[0019] The invention has the beneficial effects that: in the first step of the invention, chlorosulfonic acid is used as a sulfonating agent in a microchannel reactor to carry out a sulfonation reaction with toluene and a catalyst to prepare a p-toluenesulfonic acid mixed solution, and the p-toluenesulfonic acid mixed solution is then synthesized with chlorosulfonic acid and an organic solvent in a second microreactor to prepare a green process of p-toluenesulfonyl chloride. The invention has continuous production, can realize accurate control of reaction temperature, reaction time, and reaction material ratio, greatly improves the production efficiency of p-toluenesulfonyl chloride, and due to the addition of an inhibitor, effectively solves the problem of easily generating a large amount of byproducts such as sulfone substances and polysulfonated substances during the reaction process, and avoids corrosion of equipment by hydrogen chloride gas.

[0020] Preferably, the molar ratio of the chlorosulfonic acid, the catalyst and the organic solvent added at one time in step (1) is 1:0.01-0.02:1.0-3.0.

[0021] Based on the above technical solution, the present invention can also be improved as follows.

[0022] Furthermore, the temperature in the first static mixer is 25°C-45°C; the temperature in the second static mixer is 35°C-65°C.

[0023] Furthermore, the mixed solution B in step (2) includes the following materials: a catalyst, an organic solvent, and an inhibitor.

[0024] Furthermore, the molar ratio of the liquid phase in step (2) to the organic solvent, the chlorosulfonic acid, the catalyst, and the inhibitor in the mixed solution B is 1: 1.0-3.0: 0.01-0.02: 0.01-0.22: 0.01-0.3.

[0025] The beneficial effect of adopting the above further scheme is that the sulfonation reaction and the chlorination reaction of the present application are carried out in steps, and the proportion of chlorosulfonic acid in the steps is strictly controlled to avoid the side reaction after excessive addition to generate by-products such as o-toluenesulfonyl chloride, thereby greatly improving the yield of toluenesulfonyl chloride.

[0026] Furthermore, the catalyst is ammonium chloride; and the inhibitor includes at least one of acetic acid, propionic acid, isopropionic acid, chloroacetic acid, and trifluoroacetic acid.

[0027] The beneficial effect of adopting the above further scheme is that the addition of the inhibitor in the present invention can effectively prevent the sulfonation of multiple sites of toluene during the reaction to generate disulfonic acid or trisulfonic acid derivatives, as well as the generation of by-products such as sulfone substances.

[0028] Furthermore, the reaction liquid enters the second gas-liquid two-phase separator to separate into gas, sulfonated oil, an intermediate layer and a lower layer, wherein the separated gas is absorbed by the second falling film absorber, the sulfonated oil is used for refining to obtain o-benzenesulfonyl chloride, iso-benzene and sulfonyl chloride, and the lower layer is recovered and enters the sulfuric acid storage tank.

[0029] Furthermore, the organic solvent includes at least one of dichloromethane, chloroform, 1,2-dichloroethane and dichloroethane.

[0030] Furthermore, the reaction temperature in the first microreactor is 25-45° C., and the reaction time is 0-60 min; the reaction temperature in the second microreactor is 45-85° C., and the reaction time is 60-300 min.

[0031] The beneficial effect of adopting the above further scheme is that the sulfonation reaction in the first microreactor is an electrophilic substitution reaction, and this step reaction is an exothermic reaction with a fast reaction speed. In theory, increasing the reaction temperature can increase the yield of the para-position product, but experiments have found that when the temperature is too high, the color of the reaction system becomes darker, and o-toluenesulfonyl chloride, m-toluenesulfonyl chloride, and high-boiling products (sulfones) are generated in large quantities, while the yield of the main product is not improved; the present invention can achieve accurate control of the reaction temperature, reaction time, and reaction material ratio, greatly improve the production efficiency of p-toluenesulfonyl chloride, and due to the addition of the inhibitor, effectively solve the problem of easily generating a large number of sulfone substances and polysulfonated by-products during the reaction.

[0032] In the second microreactor, the yield of the target product of the acyl chlorination reaction using chlorosulfonic acid as the acyl chlorination agent increases with the increase of temperature.

[0033] Furthermore, the freezing crystallization, filtration and washing of the intermediate layer in step (3) are specifically as follows: the intermediate layer passing through its separator is separated and passed through a freezing crystallizer for freezing crystallization, and then enters a centrifuge for centrifugation and filtration; the crude product obtained by filtration is washed and then passed through a freezing crystallizer for freezing crystallization again to obtain the product.

[0034] The beneficial effects of adopting the above further scheme are: the present invention has continuous production, can realize accurate control of reaction temperature, reaction time and reaction material ratio, greatly improves the production efficiency of p-toluenesulfonyl chloride, and saves a lot of chlorosulfonic acid consumption after reuse because the hydrolysis process is omitted in the separation of target product solution, and the amount of waste sulfuric acid is also greatly reduced. Concentrated sulfuric acid is directly separated and can be used for sulfonation production of p-toluenesulfonic acid, achieving the goal of clean and safe production. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a production process flow chart of the present invention.

[0036] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0037] 1-first static mixer, 2-toluene storage tank, 3-first microreactor, 4-first gas-liquid two-phase separator, 5-first falling film absorber, 7-chlorosulfonic acid storage tank, 8-second microreactor, 9-second gas-liquid two-phase separator, 10-sulfuric acid storage tank, 11-freezing crystallizer, 12-centrifuge, 13-first metering pump, 14-second metering pump, 15-third metering pump, 16-fourth metering pump, 17-fifth metering pump, 18-sixth metering pump, 19-first liquid inlet pipe, 20-second liquid inlet pipe, 21-third liquid inlet pipe, 22-fourth liquid inlet pipe, 23-fifth liquid inlet pipe, 24-first connecting pipe, 25-second connecting pipe, 26-third connecting pipe, 27-fourth connecting pipe, 28-fifth connecting pipe, 29-absorption pipe. DETAILED DESCRIPTION

[0038] The principles and features of the present invention are described below, and the examples are only used to explain the present invention and are not used to limit the scope of the present invention. If no specific technology or conditions are specified in the embodiments, the technology or conditions described in the literature in this field or the product instructions are used. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased through regular channels.

[0039] Embodiment 1:

[0040] The process diagram of the continuous synthesis of p-toluenesulfonyl chloride of the present invention is as follows Figure 1 As shown, the details are as follows:

[0041] The reaction device used in the present invention comprises a synthesis device comprising a first static mixer 1, a toluene storage tank 2, a first microreactor 3, a first gas-liquid two-phase separator 4, a first falling film absorber 5, a second static mixer 6, a chlorosulfonic acid storage tank 7, a second microreactor 8, a second gas-liquid two-phase separator 9, a sulfuric acid storage tank 10, a freezing crystallizer 11, a centrifuge 12, a first metering pump 13, a second metering pump 14, a third metering pump 15, a fourth metering pump 16, a fifth metering pump 17, a sixth metering pump 18, a first liquid inlet pipe 19, a second liquid inlet pipe 20, a third liquid inlet pipe 21, a fourth liquid inlet pipe 22, a fifth liquid inlet pipe 23, a first connecting pipe 24, a second connecting pipe 25, a third connecting pipe 26, a fourth connecting pipe 27, a fifth connecting pipe 28, and an absorption pipe 29;

[0042] The first static mixer 1 is connected to the inlet of the first microreactor 3 via a first liquid inlet pipe 19, and a first metering pump 13 is provided on the first liquid inlet pipe 19; the toluene storage tank 2 is connected to the inlet of the first microreactor 3 via a second liquid inlet pipe 20, and a second metering pump 14 is provided on the second liquid inlet pipe 20; the first microreactor 3 is connected to the first gas-liquid two-phase separator 4 via a first connecting pipe 24;

[0043] The first gas-liquid two-phase separator 4 is provided with two outlets, the first outlet of the first gas-liquid two-phase separator 4 is connected to the first falling film absorber 5 through an absorption pipe 29; the second outlet of the first gas-liquid two-phase separator 4 is connected to the inlet of the second microreactor 8 through a third liquid inlet pipe 21; the third liquid inlet pipe 21 is provided with a third metering pump 15;

[0044] The chlorosulfonic acid storage tank 7 is connected to the inlet of the second microreactor 8 via the fourth liquid inlet pipe 22, and the fourth liquid inlet pipe 22 is provided with a fourth metering pump 16; the second static mixer 6 is connected to the second microreactor 8 via the fifth liquid inlet pipe 23, and the fifth liquid inlet pipe 23 is provided with a fifth metering pump 17;

[0045] The outlet of the second microreactor 8 is connected to the second gas-liquid two-phase separator 9 through the second connecting pipe 25; the second gas-liquid two-phase separator 9 is provided with three outlets, the first outlet of the second gas-liquid two-phase separator is connected to the second falling film absorber, the second outlet of the second gas-liquid two-phase separator 9 is connected to the inlet of the sulfuric acid storage tank 10 through the fourth connecting pipe 27, and the fourth connecting pipe 27 is provided with a sixth metering pump 18; the third outlet of the second gas-liquid two-phase separator 9 is connected to the freezing crystallizer 11 through the third connecting pipe 26, the freezing crystallizer 11 is connected to the centrifuge 12 through the third connecting pipe 26, and the centrifuge 12 is connected to the second static mixer 6 through the fifth connecting pipe 28.

[0046] The following embodiments 2-5 all adopt the above-mentioned device example.

[0047] Example 2: A continuous synthesis method of p-toluenesulfonyl chloride

[0048] (1) adding 1 mol of chlorosulfonic acid, 0.02 mol of ammonium chloride, and 1 mol of ethylene dichloride to a first static mixer 1, and mixing them uniformly at room temperature to obtain a mixed solution A; pumping the mixed solution A and 1 mol of toluene into a first microreactor 3 under the action of a first metering pump 13 for sulfonation reaction, the reaction time is 20 min, and the temperature is controlled at 30° C. to obtain a reaction solution;

[0049] (2) The reaction liquid discharged from the outlet of the first microreactor 3 enters the first gas-liquid two-phase separator 4 to obtain HCl gas and a liquid containing p-toluenesulfonic acid. The separated HCl gas enters the first falling film absorber 5 to produce hydrochloric acid, and the 1 mol liquid phase containing p-toluenesulfonic acid separated by the first gas-liquid two-phase separator 4 is pumped into the second microreactor 8 by the third metering pump 15; 2 mol of ethylene dichloride, 0.02 mol of inhibitor (a mixture of acetic acid and isopropionic acid, the molar ratio of the mixture is 1:1.5) and 0.02 mol of ammonium chloride are mixed at 30°C in the second static mixer 6 to obtain a mixed liquid B, which is pumped into the second microreactor 8 together with 1 mol of chlorosulfonic acid, and mixed with the liquid containing p-toluenesulfonic acid to obtain a mixed material, and an acyl chloride reaction is carried out, the reaction time is 300 minutes, and the temperature is controlled at 45°C;

[0050] (3) The second microreactor 8 discharges the secondary reaction mixture, which is separated by the second gas-liquid two-phase separator 9 to obtain HCl gas, sulfonated oil, an intermediate layer and a lower layer. The HCl gas enters the second falling film absorber to produce hydrochloric acid, and the sulfonated oil is refined to obtain o-benzenesulfonyl chloride, iso-benzene and sulfonyl chloride; the lower layer is recovered and enters the sulfuric acid storage tank 10. The intermediate layer is crystallized by the freezing crystallizer 11 and then centrifuged and filtered by the centrifuge 12. The crude product obtained by filtration is washed and then frozen and crystallized by the freezing crystallizer 11 again to obtain a crude product of p-toluenesulfonyl chloride. The filtrate obtained by filtration enters the chlorosulfonic acid storage tank 7 for recovery for secondary production. The total yield conversion rate of o-, m- and p-positions is 60.44%, and the TsCl yield is 44.23%.

[0051] Example 3: A continuous synthesis method of p-toluenesulfonyl chloride

[0052] (1) adding 1 mol of chlorosulfonic acid, 0.02 mol of ammonium chloride and 1 mol of ethylene dichloride to a first static mixer 1, and mixing them uniformly at room temperature to obtain a mixed solution A; pumping the mixed solution A and 1 mol of toluene into a first microreactor 3 under the action of a first metering pump 13 for sulfonation reaction, the reaction time is 20 min, and the temperature is controlled at 30° C. to obtain a reaction solution;

[0053] (2) The reaction liquid discharged from the outlet of the first microreactor 3 enters the first gas-liquid two-phase separator 4 to obtain HCl gas and a liquid containing p-toluenesulfonic acid. The separated HCl gas enters the first falling film absorber 5 to produce hydrochloric acid, and the 1 mol liquid phase containing p-toluenesulfonic acid separated by the first gas-liquid two-phase separator 4 is pumped into the second microreactor 8 by the third metering pump 15; 2 mol of dichloroethane, 0.05 mol of inhibitor (a mixture of acetic acid and isopropionic acid, the molar ratio of the mixture is 1:1.5), and 0.05 mol of ammonium chloride are added to the second static mixer 6, and mixed at 35°C to obtain a mixed liquid B, which is pumped into the second microreactor 8 together with 2 mol of chlorosulfonic acid, and mixed with the liquid containing p-toluenesulfonic acid to obtain a mixed material, and an acyl chlorination reaction is carried out, the reaction time is 300 minutes, and the temperature is controlled at 60°C;

[0054] (3) The second microreactor 8 discharges the secondary reaction mixture, which is separated by the second gas-liquid two-phase separator 9 to obtain HCl gas, sulfonated oil, an intermediate layer and a lower layer. The HCl gas enters the second falling film absorber to produce hydrochloric acid, and the sulfonated oil is refined to obtain o-benzenesulfonyl chloride and m-toluenesulfonyl chloride; the lower layer is recovered and enters the sulfuric acid storage tank 10. The intermediate layer is crystallized by the freezing crystallizer 11 and then centrifuged and filtered by the centrifuge 12. The crude product obtained by filtration is washed and then frozen and crystallized by the freezing crystallizer 11 again to obtain a crude product of p-toluenesulfonyl chloride. The filtrate obtained by filtration enters the chlorosulfonic acid storage tank 7 for recovery for secondary production. The total yield conversion rate of o-, m- and p-positions is 83.44%, and the TsCl yield is 71.23%.

[0055] Example 4: A continuous synthesis method of p-toluenesulfonyl chloride

[0056] (1) adding 1 mol of chlorosulfonic acid, 0.02 mol of ammonium chloride and 2 mol of ethylene dichloride to a first static mixer 1, and mixing them uniformly at room temperature to obtain a mixed solution A; pumping the mixed solution A and 1 mol of toluene into a first microreactor 3 under the action of a first metering pump 13 for sulfonation reaction, the reaction time is 300 min, and the temperature is controlled at 30° C. to obtain a reaction solution;

[0057] (2) The reaction liquid discharged from the outlet of the first microreactor 3 enters the first gas-liquid two-phase separator 4 to obtain HCl gas and a liquid containing p-toluenesulfonic acid. The separated HCl gas enters the first falling film absorber 5 to produce hydrochloric acid, and the 1 mol of liquid phase containing p-toluenesulfonic acid separated by the first gas-liquid two-phase separator 4 is pumped into the second microreactor 8 by the third metering pump 15; 3 mol of dichloroethane, 0.05 mol of inhibitor (a mixture of acetic acid and isopropionic acid, the molar ratio of the mixture is 1:1.5) and 0.05 mol of ammonium chloride are added to the second static mixer 6, and mixed at 45°C to obtain a mixed liquid B, which is pumped into the second microreactor 8 together with 2 mol of chlorosulfonic acid, and mixed with the liquid containing p-toluenesulfonic acid to obtain a mixed material, and an acyl chlorination reaction is carried out, the reaction time is 240 minutes, and the temperature is controlled at 60°C;

[0058] (3) The second microreactor 8 discharges the secondary reaction mixture, which is separated by the second gas-liquid two-phase separator 9 to obtain HCl gas, sulfonated oil, an intermediate layer and a lower layer. The HCl gas enters the second falling film absorber to produce hydrochloric acid, and the sulfonated oil is refined to obtain o-benzenesulfonyl chloride and m-toluenesulfonyl chloride; the lower layer is recovered and enters the sulfuric acid storage tank 10. The intermediate layer is crystallized by the freezing crystallizer 11 and then centrifuged and filtered by the centrifuge 12. The crude product obtained by filtration is washed and then frozen and crystallized by the freezing crystallizer 11 again to obtain a crude product of p-toluenesulfonyl chloride. The filtrate obtained by filtration enters the chlorosulfonic acid storage tank 7 for recovery for secondary production. The total yield conversion rate of o-, m- and p-positions is 90.44%, and the TsCl yield is 80.34%.

[0059] Example 5: A continuous synthesis method of p-toluenesulfonyl chloride

[0060] (1) adding 1 mol of chlorosulfonic acid, 0.02 mol of ammonium chloride and 2 mol of ethylene dichloride to a first static mixer 1, and mixing them uniformly at room temperature to obtain a mixed solution A; pumping the mixed solution A and 1 mol of toluene into a first microreactor 3 under the action of a first metering pump 13 for sulfonation reaction, the reaction time is 30 min, and the temperature is controlled at 60° C. to obtain a reaction solution;

[0061] (2) The reaction liquid discharged from the outlet of the first microreactor 3 enters the first gas-liquid two-phase separator 4 to obtain HCl gas and a liquid containing p-toluenesulfonic acid. The separated HCl gas enters the first falling film absorber 5 to produce hydrochloric acid, and the 1 mol liquid phase containing p-toluenesulfonic acid separated by the first gas-liquid two-phase separator 4 is pumped into the second microreactor 8 by the third metering pump 15; 3 mol of dichloroethane, 0.1 mol of inhibitor (a mixture of acetic acid and isopropionic acid, the molar ratio of the mixture is 1:1.5) and 0.1 mol of ammonium chloride are added to the second static mixer 6 and mixed at 30°C to obtain a mixed liquid B, which is pumped into the second microreactor 8 together with 2 mol of chlorosulfonic acid, mixed with the liquid containing p-toluenesulfonic acid to obtain a mixed material, and an acyl chloride reaction is carried out, the reaction time is 240 minutes, and the temperature is controlled at 60°C;

[0062] (3) The second microreactor 8 discharges the secondary reaction mixture, which is separated by the second gas-liquid two-phase separator 9 to obtain HCl gas, sulfonated oil, an intermediate layer and a lower layer. The HCl gas enters the second falling film absorber to produce hydrochloric acid, and the sulfonated oil is refined to obtain o-benzenesulfonyl chloride and m-toluenesulfonyl chloride; the lower layer is recovered and enters the sulfuric acid storage tank 10. The intermediate layer is crystallized by the freezing crystallizer 11 and then centrifuged and filtered by the centrifuge 12. The crude product obtained by filtration is washed and then frozen and crystallized by the freezing crystallizer 11 again to obtain a crude product of p-toluenesulfonyl chloride. The filtrate obtained by filtration enters the chlorosulfonic acid storage tank 7 for recovery for secondary production. The total yield conversion rate of o-, m- and p-positions is 92.24%, and the TsCl yield is 81.68%.

[0063] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A continuous synthesis device for p-toluenesulfonyl chloride, characterized in that: The synthesis device comprises a first static mixer (1), a toluene storage tank (2), a first microreactor (3), a first gas-liquid two-phase separator (4), a first falling film absorber (5), a second static mixer (6), a chlorosulfonic acid storage tank (7), a second microreactor (8), a second gas-liquid two-phase separator (9), a sulfuric acid storage tank (10), a freezing crystallizer (11), a centrifuge (12), a first metering pump (13), a second metering pump (14), a third metering pump (15), a fourth metering pump (16), a fifth metering pump (17), a sixth metering pump (18), a first liquid inlet pipe (19), a second liquid inlet pipe (20), a third liquid inlet pipe (21), a fourth liquid inlet pipe (22), a fifth liquid inlet pipe (23), a first connecting pipe (24), a second connecting pipe (25), a third connecting pipe (26), a fourth connecting pipe (27), a fifth connecting pipe (28), and an absorption pipe (29); The first static mixer (1) is connected to the inlet of the first microreactor (3) via the first liquid inlet pipe (19), and the first liquid inlet pipe (19) is provided with the first metering pump (13); the toluene storage tank (2) is connected to the inlet of the first microreactor (3) via the second liquid inlet pipe (20), and the second liquid inlet pipe (20) is provided with the second metering pump (14); the first microreactor (3) is connected to the first gas-liquid two-phase separator (4) via the first connecting pipe (24); The first gas-liquid two-phase separator (4) is provided with two outlets, the first outlet of the first gas-liquid two-phase separator (4) is connected to the first falling film absorber (5) through the absorption pipe (29); the second outlet of the first gas-liquid two-phase separator (4) is connected to the inlet of the second microreactor (8) through the third liquid inlet pipe (21); the third liquid inlet pipe (21) is provided with the third metering pump (15); The chlorosulfonic acid storage tank (7) is connected to the inlet of the second microreactor (8) via the fourth liquid inlet pipe (22), and the fourth liquid inlet pipe (22) is provided with the fourth metering pump (16); the second static mixer (6) is connected to the second microreactor (8) via the fifth liquid inlet pipe (23), and the fifth liquid inlet pipe (23) is provided with the fifth metering pump (17); The outlet of the second microreactor (8) is connected to the second gas-liquid two-phase separator (9) through a second connecting pipe (25); the second gas-liquid two-phase separator (9) is provided with three outlets, the first outlet of the second gas-liquid two-phase separator (9) is connected to the second falling film absorber; the second outlet of the second gas-liquid two-phase separator (9) is connected to the inlet of the sulfuric acid storage tank (10) through the fourth connecting pipe (27), and the sixth metering pump (18) is arranged on the fourth connecting pipe (27); the third outlet of the second gas-liquid two-phase separator (9) is connected to the freezing crystallizer (11) through the third connecting pipe (26), and the freezing crystallizer (11) is further connected to the centrifuge (12) through the third connecting pipe (26), and the centrifuge (12) is connected to the second static mixer (6) through the fifth connecting pipe (28).

2. A continuous synthesis method of p-toluenesulfonyl chloride, characterized in that: The method for continuously synthesizing p-toluenesulfonyl chloride using the continuous synthesis device according to claim 1 is as follows: (1) mixing chlorosulfonic acid, a catalyst, and an organic solvent added at once in a first static mixer (1) to obtain a mixed solution A, and pumping the mixed solution A and toluene into a first microreactor (3) to react to obtain a reaction solution; (2) discharging the reaction liquid from the outlet of the first microreactor (3) and separating the liquid phase; the liquid phase and the chlorosulfonic acid added for the second time are respectively pumped into the second microreactor (8) with the mixed liquid B in the second static mixer (6) for mixing; and reacting in the second microreactor (8) to obtain a secondary reaction mixture; (3) discharging the secondary reaction mixture from the second microreactor (8) and separating the intermediate layer of frozen crystals, filtering and washing to obtain p-toluenesulfonyl chloride.

3. A continuous synthesis method of p-toluenesulfonyl chloride according to claim 2, characterized in that, The temperature in the first static mixer (1) is 25°C-45°C; the temperature in the second static mixer (6) is 35°C-65°C.

4. A continuous synthesis method of p-toluenesulfonyl chloride according to claim 2, characterized in that, The mixed solution B in step (2) includes the following materials: a catalyst, an organic solvent, and an inhibitor.

5. A continuous synthesis method of p-toluenesulfonyl chloride according to claim 4, characterized in that, The molar ratio of the liquid phase, the chlorosulfonic acid, the organic solvent, the catalyst and the inhibitor in the mixed solution B in step (2) is 1:1-3.0:1-3.0:0.01-0.22:0.01-0.

3.

6. A continuous synthesis method of p-toluenesulfonyl chloride according to claim 4, characterized in that, The catalyst is ammonium chloride; The inhibitor includes at least one of acetic acid, propionic acid, isopropionic acid, chloroacetic acid, and trifluoroacetic acid.

7. A continuous synthesis method of p-toluenesulfonyl chloride according to claim 6, characterized in that: The reaction liquid enters the second gas-liquid two-phase separator (9) to separate into gas, sulfonated oil, an intermediate layer and a lower layer, wherein the separated gas is absorbed by the second falling film absorber, the sulfonated oil is used for refining to obtain o-benzenesulfonyl chloride, iso-benzene and sulfonyl chloride, and the lower layer is recovered and enters the sulfuric acid storage tank (10).

8. A continuous synthesis method of p-toluenesulfonyl chloride according to claim 2, characterized in that: The organic solvent includes at least one of dichloromethane, chloroform, 1,2-dichloroethane and dichloroethane.

9. A continuous synthesis method of p-toluenesulfonyl chloride according to claim 2, characterized in that: The reaction temperature in the first microreactor is 25-45° C., and the reaction time is 0-60 min; the reaction temperature in the second microreactor is 45-85° C., and the reaction time is 60-300 min.

10. A continuous synthesis method of p-toluenesulfonyl chloride according to claim 2, characterized in that: The steps of freezing crystallization, filtering and washing of the intermediate layer in step (3) are specifically as follows: the intermediate layer is separated by its separator and passed through a freezing crystallizer (11) for freezing crystallization, and then enters a centrifuge (12) for centrifugation and filtration; the crude product obtained by filtration is washed and then passed through a freezing crystallizer (11) for freezing crystallization again to obtain a product.

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