Method for preparing o-sulfonyl chloride / amine methyl benzoate from o-chloromethyl benzoate

Abstract

The invention relates to the technical field of organic synthesis, and provides a method for preparing o-sulfonyl chloride / amine methyl benzoate by using o-chloromethyl benzoate. The preparation method comprises the following steps: 1, mixing methyl o-chlorobenzoate and pure water, stirring, adding sodium thiosulfate, and heating for reaction to obtain a solution; the preparation method comprises the following steps: adding dichloroethane and pure water into a reaction kettle, stirring, cooling, introducing chlorine, dropwise adding a solution, controlling the dropwise adding time and the temperature of the reaction kettle, carrying out a heat preservation reaction, removing chlorine, and drying to obtain o-sulfonyl chloride methyl benzoate; and 2, on the basis of the prepared o-sulfonyl chloride methyl benzoate, adding the o-sulfonyl chloride methyl benzoate into methanol while stirring, cooling, adding an ammonia solution, heating for reaction to generate a crude o-sulfonamide methyl benzoate product, and adding an adsorbent for purification to obtain the o-sulfonamide methyl benzoate. The preparation method disclosed by the invention is relatively low in production cost, less in waste gas and waste water and capable of realizing coordinated development of economic benefits and environmental benefits, and the o-sulfonyl chloride / methyl aminobenzoate is high in purity.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis, and particularly relates to a method for preparing methyl o-sulfonyl chloride / amine benzoate by using methyl o-chlorobenzoate. Background Art

[0002] Methyl o-chlorobenzoate is an important organic intermediate. Due to the active chlorine atom and ester group in its molecular structure, it is an ideal substrate for various chemical reactions and is widely used in the synthesis of various chemicals, including medicines, pesticides, fragrances and dyes. The derivatives of methyl o-chlorobenzoate, especially methyl o-sulfonylchlorobenzoate and methyl o-sulfonamidobenzoate, play a key role in the synthesis of specific chemicals saccharin and saccharin sodium and their related derivatives.

[0003] Methyl o-chlorobenzoate is an ideal substrate for various chemical reactions because of the active chlorine atoms and ester groups in its molecular structure. It can participate in many types of chemical reactions, such as substitution, addition, elimination, etc., and provides a wide range of application prospects for the synthesis of different types of compounds. Methyl o-sulfonylchlorobenzoate is a key synthetic intermediate, especially in the synthesis of sulfonamide drugs and certain herbicides. The sulfonyl chloride group it contains is highly active and can be further converted into a sulfonamide group, which is essential for the synthesis of biologically active compounds. Methyl o-sulfonamide benzoate is a key intermediate for the synthesis of a variety of drugs and pesticides, and is mainly used in the synthesis of sulfonylurea herbicides. Its traditional synthesis method is to obtain it by esterification of saccharin with methanol. The methyl o-sulfonamide benzoate obtained by this process is costly and has low purity.

[0004] Therefore, it is urgent to develop a method for preparing methyl o-sulfonyl chloride / amine benzoate from methyl o-chlorobenzoate, which can not only improve the purity of the two, but also simplify the process and save costs. Summary of the invention

[0005] In view of the existing technical problems, the object of the present invention is to provide a method for preparing methyl o-sulfonyl chloride / amine benzoate from methyl o-chlorobenzoate. The preparation method of the present invention has low production cost, less waste gas and waste water, and the adsorbent has regeneration, achieving coordinated development of economic benefits and environmental benefits, and the purity of methyl o-sulfonyl chloride / amine benzoate is high, and the whiteness of methyl o-sulfonamide benzoate is good, so it has good application value.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] The present invention provides a method for preparing methyl o-sulfonylchlorobenzoate from methyl o-chlorobenzoate, comprising the following steps:

[0008] (1) methyl o-chlorobenzoate and pure water are mixed, stirred, sodium thiosulfate is added, heated for reaction, and cooled to obtain a solution;

[0009] (2) Add dichloroethane and pure water to a reaction kettle, stir, cool to 5-10°C, introduce chlorine gas, and dropwise add the solution obtained in step (1). Control the dropping time for 2-3h to ensure that the temperature of the reaction kettle does not exceed 15-30°C. Keep the temperature for reaction, start the vacuum pump to ensure a slight negative pressure in the reaction kettle, then add sodium thiosulfate, stir, stand for phase separation, and dry to obtain methyl o-sulfonylchlorobenzoate.

[0010] The reaction mechanism and effects of the present invention are as follows:

[0011] The present invention regulates the mass ratio of methyl o-chlorobenzoate and sodium thiosulfate and the mass ratio of the solution, chlorine gas and pure water, optimizes the reaction conditions, reduces the occurrence of side reactions, improves the selectivity of the product, and further improves the purity of methyl o-sulfonylchlorobenzoate.

[0012] In some embodiments, the molar ratio of methyl o-chlorobenzoate to sodium thiosulfate in step (1) is 1:(1.2-1.6), and the mass ratio of methyl o-chlorobenzoate to pure water is 1:(2-3).

[0013] Preferably, in step (1), the stirring speed is 70-100 r / min, the reaction temperature is 65-95° C., and the reaction time is 2-5 h.

[0014] In some embodiments, the mass ratio of the solution, chlorine gas and pure water in step (2) is 1:(0.4-0.65):(0.004-0.008).

[0015] Preferably, in step (2), the mass ratio of the solution to dichloroethane is 1:(0.4-0.8).

[0016] In some embodiments, the purity of methyl o-sulfonylchlorobenzoate prepared by the method is not less than 98%.

[0017] Another aspect of the present invention provides a method for preparing methyl o-sulfonamide benzoate from methyl o-chlorobenzoate, comprising the following steps:

[0018] S1. Preparation of methyl o-sulfonyl chlorobenzoate

[0019] (1) methyl o-chlorobenzoate and pure water are mixed, stirred, sodium thiosulfate is added, heated for reaction, and cooled to obtain a solution;

[0020] (2) adding dichloroethane and pure water to a reaction kettle, stirring, cooling to 5-10° C., introducing chlorine gas, and dripping the solution obtained in step (1), controlling the dripping time to 2-3 hours, ensuring that the temperature of the reaction kettle does not exceed 15-30° C., and then keeping the temperature for reaction, turning on the vacuum pump to ensure a slight negative pressure in the reaction kettle, and then adding sodium thiosulfate, stirring, standing for phase separation, and drying to obtain methyl o-sulfonyl chlorobenzoate;

[0021] S2. Preparation of methyl o-sulfonamide benzoate

[0022] Methyl o-sulfonylchlorobenzoate was added to methanol with stirring, cooled, and ammonia solution was added. The mixture was heated to 40-60° C. and reacted for 2-3 hours to generate crude methyl o-sulfonylamidebenzoate, which was purified to obtain methyl o-sulfonylamidebenzoate.

[0023] The reaction mechanism and effects of the present invention are as follows:

[0024] 1. Beet pulp is a byproduct of the sugar beet industry. It is widely available and low-cost. Using it as a raw material for adsorbents can reduce waste and production costs. Beet pulp fiber has a large number of active hydroxyl structures in the cellulose molecules. Its active groups easily form hydrogen bonds with other hydroxyl groups, enhancing the stability of the linear structure of the cellulose molecular chain and presenting a highly ordered crystalline region. The adsorption process mainly occurs in the amorphous region. This crystalline region hinders the adsorption process and the adsorption effect is greatly limited.

[0025] The present invention uses citric acid and sodium hydroxide for pretreatment, which is a common environmentally friendly method, and the chemicals used in the entire synthesis process are basically non-toxic or low-toxic. On the one hand, the beet pulp fiber treated with acid and alkali has a higher specific surface area after drying, which is conducive to improving the adsorption capacity of the adsorbent. Further, by introducing trimethylolpropane triglycidyl ether and N-tert-butyloxycarbonyl-1,2-ethylenediamine, the functional groups on the surface of the adsorbent, such as hydroxyl and amine groups, can be increased, which can form stronger chemical bonds with by-products, thereby improving the adsorption capacity and adsorption selectivity of the adsorbent, and the decolorization rate is high. On the other hand, the modified beet pulp fiber adsorbent has good mechanical stability and regeneration ability, and its adsorption performance can be restored by simple chemical treatment, realizing recycling, greatly improving the economy and environmental protection of the adsorbent, and conforming to the development trend of green chemistry and sustainable chemistry.

[0026] 2. The present invention improves the purity and whiteness of methyl o-sulfonamide benzoate by a specific purification method and by adding an adsorbent.

[0027] In some embodiments, the ammonia solution in step S2 is a methanol solution of ammonia with a mass fraction of 15-30%.

[0028] Preferably, in step S2, the dosage ratio of methyl o-sulfonylchlorobenzoate and ammonia solution is 1 g: (2-3.5) ml.

[0029] In some embodiments, the mass ratio of methyl o-sulfonylchlorobenzoate to methanol in step S2 is 1:(2-3).

[0030] In some embodiments, the specific steps of purification in step S2 are as follows:

[0031] The crude product of methyl o-sulfonamide benzoate is dissolved in toluene, heated to 85-95°C while stirring, an adsorbent is added, and stirring is continued for 1-1.5 hours; the temperature is raised to 100-105°C, filtered, naturally crystallized, filtered, and naturally dried to obtain methyl o-sulfonamide benzoate.

[0032] Preferably, the mass ratio of the crude methyl o-sulfonamide benzoate to the adsorbent is 10:(0.8-1.2).

[0033] In some embodiments, the method for preparing the adsorbent comprises the following steps:

[0034] Q1. After removing impurities from beet pulp, wash it with clean water, filter it, dry it, crush it, and pass it through a 20-60 mesh sieve to obtain beet pulp powder; add distilled water, stir it, add 2-5 mol / L citric acid aqueous solution, heat it for reaction, filter it, wash it, and dry it to obtain beet pulp fiber;

[0035] Q2. The beet pulp fiber obtained in step Q1 is dispersed in an aqueous sodium hydroxide solution, stirred, filtered, and the resulting residue is poured into distilled water, stirred, filtered, washed, and dried to obtain alkali-treated beet pulp fiber;

[0036] Q3. The alkali-treated beet pulp fiber obtained in step Q2 is added to a reactor, and 0.1-0.2 mol / L sodium hydroxide aqueous solution and trimethylolpropane triglycidyl ether are added in sequence, heated to 50-70°C and stirred for reaction for 4-6 hours, filtered, washed, and dried to obtain an intermediate product;

[0037] Q4. Disperse the intermediate product obtained in step Q3 into deionized water and soak for 30-45 minutes, then add N-tert-butyloxycarbonyl-1,2-ethylenediamine and sodium bicarbonate in sequence, heat to 60-100°C and react for 4-6 hours, filter, wash, and dry to obtain an adsorbent.

[0038] In some embodiments, the mass ratio of the beet pulp powder and the citric acid aqueous solution in step Q1 is 1 g: (8-13) ml.

[0039] In some embodiments, the ratio of the alkali-treated beet pulp fiber, sodium hydroxide aqueous solution and trimethylolpropane triglycidyl ether used in step Q3 is 1 g: (45-55) ml: (4-6) g.

[0040] In some embodiments, the concentration of the sodium hydroxide aqueous solution in step Q2 is 0.15-0.3 mol / L, and the usage ratio of beet pulp fiber to the sodium hydroxide aqueous solution is 1 g: (16-24) ml.

[0041] In some embodiments, the mass ratio of the intermediate product in step Q4 to N-tert-butyloxycarbonyl-1,2-ethylenediamine is 1:(3-6).

[0042] In some embodiments, the purity of methyl o-sulfonamide benzoate prepared by the method is not less than 96%, and the whiteness of methyl o-sulfonamide benzoate is not less than 92%.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] 1. The preparation method of the present invention has low production cost, less waste gas and waste water, and the adsorbent is regenerative, thus achieving coordinated development of economic benefits and environmental benefits, and the purity of o-sulfonyl chloride / methyl amine benzoate is high.

[0045] 2. The present invention improves the purity and whiteness of methyl o-sulfonamide benzoate by a specific purification method and adding an adsorbent. The adsorbent of the present invention has a high specific surface area, strong adsorption, and a high decolorization rate; at the same time, the adsorbent has good mechanical stability and regeneration ability, which is in line with the development trend of green chemistry and sustainable chemistry.

[0046] 3. The present invention regulates the mass ratio of methyl o-chlorobenzoate and sodium thiosulfate and the mass ratio of solution, chlorine and pure water to improve the purity of methyl o-sulfonylchlorobenzoate. DETAILED DESCRIPTION

[0047] The present invention will be described below in conjunction with specific embodiments. It should be noted that the following embodiments are examples of the present invention and are only used to illustrate the present invention, rather than to limit the present invention. Other combinations and various modifications within the concept of the present invention may be performed without departing from the spirit or scope of the present invention.

[0048] According to the ratios of the raw materials and the preparation methods specified in the following examples and comparative examples, methyl o-sulfonyl chloride / amine benzoate was synthesized.

[0049] In order to facilitate those skilled in the art to implement the present invention, the raw materials of the embodiments and comparative examples are not particularly described and can all be purchased from the market.

[0050] Preparation Example 1

[0051] The preparation method of adsorbent A comprises the following steps:

[0052] Q1. After removing impurities from beet pulp, wash it with clean water, filter it, dry it at 45℃ to constant weight, crush it, and pass it through a 40-mesh sieve to obtain beet pulp powder; take 1kg of beet pulp powder, add 10L of distilled water, stir it for 1h, add 10L of 3.5mol / L citric acid aqueous solution, heat it to 75℃ to react for 12h, filter it, wash it with distilled water until it is neutral, and dry it at 60℃ to constant weight to obtain beet pulp fiber;

[0053] Q2. 0.5 kg of beet pulp fiber obtained in step Q1 was dispersed in 10 L of 0.3 mol / L sodium hydroxide aqueous solution, stirred at 200 rpm for 2 h, filtered, and the obtained residue was poured into 10 L of distilled water, stirred at 200 rpm for 1 h, filtered, and then washed with distilled water until neutral, and dried at 60 ° C to constant weight to obtain alkali-treated beet pulp fiber;

[0054] Q3. 0.4 kg of alkali-treated beet pulp fiber obtained in step Q2 was added to a reactor, and 20 L of 0.15 mol / L sodium hydroxide aqueous solution and 2 kg of trimethylolpropane triglycidyl ether were added in sequence, heated to 60 ° C and stirred for reaction for 5 h, filtered, washed with acetone and deionized water in sequence until neutral, and dried at 60 ° C to constant weight to obtain an intermediate product;

[0055] Q4. Disperse 0.2 kg of the intermediate product obtained in step Q3 into 5 L of deionized water and soak for 45 min. Then add 0.8 kg of N-tert-butyloxycarbonyl-1,2-ethylenediamine and 0.1 kg of sodium bicarbonate in sequence. Heat to 80 ° C for reaction for 5 h. Filter with suction, wash with acetone and deionized water in sequence until neutral, and dry at 60 ° C to constant weight to obtain adsorbent A.

[0056] Preparation Example 2

[0057] The preparation method of adsorbent B is the same as that of Preparation Example 1, except that the amount of citric acid aqueous solution added in step Q1 is 7 L.

[0058] Preparation Example 3

[0059] The preparation method of adsorbent C is the same as that of Preparation Example 1, except that the amount of trimethylolpropane triglycidyl ether added in step Q3 is 1.5 kg.

[0060] Example 1

[0061] A method for preparing methyl o-sulfonylchlorobenzoate from methyl o-chlorobenzoate comprises the following steps:

[0062] (1) 34 kg of methyl o-chlorobenzoate and 85 kg of pure water were mixed, stirred at 80 r / min for 25 min, 44.5 kg of sodium thiosulfate was added, and the mixture was heated to 80° C. and reacted for 3.5 h to obtain a solution;

[0063] (2) Add 60 kg of ethylene dichloride and 0.6 kg of pure water to a reactor, stir for 30 min, cool to 8 ° C, introduce 50 kg of chlorine gas, add 100 kg of the solution obtained in step (1), control the dropwise addition time to 2.5 h, ensure that the temperature of the reactor does not exceed 20 ° C, keep the temperature for another 2 h, turn on the vacuum pump to ensure a slight negative pressure in the reactor, add 6 kg of sodium thiosulfate, stir for 1 h, stand for phase separation, and dry at 60 ° C to constant weight to obtain methyl o-sulfonyl chlorobenzoate.

[0064] Example 2

[0065] A method for preparing methyl o-sulfonylchlorobenzoate from methyl o-chlorobenzoate comprises the following steps:

[0066] (1) 34 kg of methyl o-chlorobenzoate and 68 kg of pure water were mixed, stirred at 70 r / min for 30 min, 37.95 kg of sodium thiosulfate was added, and the mixture was heated to 95° C. and reacted for 2 h to obtain a solution;

[0067] (2) Add 40 kg of ethylene dichloride and 0.4 kg of pure water to a reactor, stir for 30 min, cool to 5 ° C, introduce 40 kg of chlorine gas, add 100 kg of the solution obtained in step (1), control the dropwise addition time to 2 h, ensure that the temperature of the reactor does not exceed 15 ° C, keep the reaction temperature for another 2 h, turn on the vacuum pump to ensure a slight negative pressure in the reactor, add 4 kg of sodium thiosulfate, stir for 1 h, stand for phase separation, and dry at 60 ° C to constant weight to obtain methyl o-sulfonyl chlorobenzoate.

[0068] Example 3

[0069] A method for preparing methyl o-sulfonylchlorobenzoate from methyl o-chlorobenzoate comprises the following steps:

[0070] (1) 34 kg of methyl o-chlorobenzoate and 102 kg of pure water were mixed, stirred at 100 r / min for 20 min, 50.5 kg of sodium thiosulfate was added, and the mixture was heated to 65° C. and reacted for 5 h to obtain a solution;

[0071] (2) 80 kg of ethylene dichloride and 0.8 kg of pure water were added to a reactor, stirred for 30 min, cooled to 10 ° C, 65 kg of chlorine gas was introduced, and 100 kg of the solution obtained in step (1) was added. The dropwise addition time was controlled to be 3 h, and the temperature of the reactor was ensured not to exceed 30 ° C. The reaction was kept warm for another 2 h, and the vacuum pump was turned on to ensure a slight negative pressure in the reactor. 8 kg of sodium thiosulfate was added, stirred for 1 h, allowed to stand for phase separation, and dried at 60 ° C to constant weight to obtain methyl o-sulfonyl chlorobenzoate.

[0072] Example 4

[0073] A method for preparing methyl o-sulfonylchlorobenzoate from methyl o-chlorobenzoate, the specific implementation method is the same as that of Example 1, except that the amount of sodium thiosulfate added in step (1) is 31.6 kg.

[0074] Example 5

[0075] A method for preparing methyl o-sulfonylchlorobenzoate from methyl o-chlorobenzoate, the specific implementation method is the same as that of Example 1, except that the amount of chlorine added in step (2) is 38 kg.

[0076] Example 6

[0077] A method for preparing methyl o-sulfonamide benzoate from methyl o-chlorobenzoate comprises the following steps:

[0078] S1. Preparation of methyl o-sulfonyl chlorobenzoate

[0079] (1) 34 kg of methyl o-chlorobenzoate and 85 kg of pure water were mixed, stirred at 80 r / min for 25 min, 44.5 kg of sodium thiosulfate was added, and the mixture was heated to 80° C. and reacted for 3.5 h to obtain a solution;

[0080] (2) adding 60 kg of ethylene dichloride and 0.6 kg of pure water to a reactor, stirring for 30 min, cooling to 8 ° C, introducing 50 kg of chlorine gas, adding 100 kg of the solution obtained in step (1), controlling the dropwise addition time to 2.5 h, ensuring that the reactor temperature does not exceed 20 ° C, and then keeping the temperature for 2 h, turning on the vacuum pump to ensure a slight negative pressure in the reactor, and then adding 6 kg of sodium thiosulfate, stirring for 1 h, standing for phase separation, and drying at 60 ° C to constant weight to obtain methyl o-sulfonyl chlorobenzoate;

[0081] S2. Preparation of methyl o-sulfonamide benzoate

[0082] 10 kg of methyl o-sulfonylchlorobenzoate was added to 25 kg of methanol while stirring, cooled to 10°C, 30 ml of 20 wt% ammonia methanol solution was added, heated to 50°C, and reacted for 2.5 hours to generate crude methyl o-sulfonamide benzoate; 8 kg of crude methyl o-sulfonamide benzoate was dissolved in 120 kg of toluene, heated to 90°C while stirring, 0.8 kg of adsorbent A was added, and stirring was continued for 1 hour; the temperature was raised to 100°C, filtered, naturally crystallized, filtered, and naturally dried to constant weight to obtain methyl o-sulfonamide benzoate.

[0083] Example 7

[0084] A method for preparing methyl o-sulfonamide benzoate from methyl o-chlorobenzoate comprises the following steps:

[0085] S1. Preparation of methyl o-sulfonyl chlorobenzoate

[0086] (1) 34 kg of methyl o-chlorobenzoate and 85 kg of pure water were mixed, stirred at 80 r / min for 25 min, 44.5 kg of sodium thiosulfate was added, and the mixture was heated to 80° C. and reacted for 3.5 h to obtain a solution;

[0087] (2) adding 60 kg of ethylene dichloride and 0.6 kg of pure water to a reactor, stirring for 30 min, cooling to 8 ° C, introducing 50 kg of chlorine gas, adding 100 kg of the solution obtained in step (1), controlling the dropwise addition time to 2.5 h, ensuring that the reactor temperature does not exceed 20 ° C, and then keeping the temperature for 2 h, turning on the vacuum pump to ensure a slight negative pressure in the reactor, and then adding 6 kg of sodium thiosulfate, stirring for 1 h, standing for phase separation, and drying at 60 ° C to constant weight to obtain methyl o-sulfonyl chlorobenzoate;

[0088] S2. Preparation of methyl o-sulfonamide benzoate

[0089] 10 kg of methyl o-sulfonylchlorobenzoate was added to 20 kg of methanol while stirring, cooled to 10°C, 20 ml of 30 wt% ammonia methanol solution was added, heated to 40°C, and reacted for 3 hours to generate crude methyl o-sulfonamide benzoate; 8 kg of crude methyl o-sulfonamide benzoate was dissolved in 120 kg of toluene, heated to 85°C while stirring, 0.64 kg of adsorbent A was added, and stirring was continued for 1.5 hours; the temperature was raised to 100°C, filtered, naturally crystallized, filtered, and naturally dried to constant weight to obtain methyl o-sulfonamide benzoate.

[0090] Example 8

[0091] A method for preparing methyl o-sulfonamide benzoate from methyl o-chlorobenzoate comprises the following steps:

[0092] S1. Preparation of methyl o-sulfonyl chlorobenzoate

[0093] (1) 34 kg of methyl o-chlorobenzoate and 85 kg of pure water were mixed, stirred at 80 r / min for 25 min, 44.5 kg of sodium thiosulfate was added, and the mixture was heated to 80° C. and reacted for 3.5 h to obtain a solution;

[0094] (2) adding 60 kg of ethylene dichloride and 0.6 kg of pure water to a reactor, stirring for 30 min, cooling to 8 ° C, introducing 50 kg of chlorine gas, adding 100 kg of the solution obtained in step (1), controlling the dropwise addition time to 2.5 h, ensuring that the reactor temperature does not exceed 20 ° C, and then keeping the temperature for 2 h, turning on the vacuum pump to ensure a slight negative pressure in the reactor, and then adding 6 kg of sodium thiosulfate, stirring for 1 h, standing for phase separation, and drying at 60 ° C to constant weight to obtain methyl o-sulfonyl chlorobenzoate;

[0095] S2. Preparation of methyl o-sulfonamide benzoate

[0096] 10 kg of methyl o-sulfonylchlorobenzoate was added to 30 kg of methanol while stirring, cooled to 10°C, 35 ml of 15 wt% ammonia methanol solution was added, heated to 60°C, and reacted for 2 hours to generate crude methyl o-sulfonamide benzoate; 8 kg of crude methyl o-sulfonamide benzoate was dissolved in 120 kg of toluene, heated to 95°C while stirring, 0.96 kg of adsorbent A was added, and stirring was continued for 1 hour; the temperature was raised to 105°C, filtered, naturally crystallized, filtered, and naturally dried to constant weight to obtain methyl o-sulfonamide benzoate.

[0097] Example 9

[0098] A method for preparing methyl o-sulfonamide benzoate from methyl o-chlorobenzoate, the specific implementation method is the same as Example 6, except that an equal amount of adsorbent B is used to replace adsorbent A.

[0099] Example 10

[0100] A method for preparing methyl o-sulfonamide benzoate from methyl o-chlorobenzoate, the specific implementation method is the same as Example 6, except that an equal amount of adsorbent C is used to replace adsorbent A.

[0101] Embodiment 11

[0102] A method for preparing methyl o-sulfonamide benzoate from methyl o-chlorobenzoate, the specific implementation method is the same as Example 6, except that an equal amount of commercially available activated carbon is used to replace adsorbent A.

[0103] Effect evaluation:

[0104] The purity of the methyl o-sulfonylchlorobenzoate synthesized in the above Examples 1-5 and the purity and whiteness of the methyl o-sulfonylamidebenzoate synthesized in Examples 6-11 were tested. The purity was determined using a liquid chromatograph, and the whiteness of the methyl o-sulfonylamidebenzoate before and after purification was determined using a whiteness meter. The whiteness of the methyl o-sulfonylchlorobenzoate without purification was 45%. The specific results are shown in Table 1.

[0105] Table 1

[0106]

[0107] From the results in Table 1, it can be seen that the purity of methyl o-sulfonylchlorobenzoate prepared in Examples 1-3 is higher, the purity of methyl o-sulfonamidebenzoate prepared in Examples 6-8 is higher, and the whiteness of methyl o-sulfonamidebenzoate is better.

[0108] Compared with Example 1, Example 4-5 changes the molar ratio of methyl o-chlorobenzoate and sodium thiosulfate, and Example 5 changes the mass ratio of solution, chlorine gas and pure water, both of which increase the by-products, affect the formation of methyl o-sulfonylchlorobenzoate, and cause the purity of methyl o-sulfonylchlorobenzoate to decrease.

[0109] Compared with Example 6, when preparing the adsorbent, Example 9 changes the dosage ratio of beet pulp powder and citric acid aqueous solution, and Example 10 changes the dosage ratio of alkali-treated beet pulp fiber, sodium hydroxide aqueous solution and trimethylolpropane triglycidyl ether, both of which will reduce the active sites and deteriorate the performance of the synthesized adsorbent, thereby affecting the purity and whiteness of methyl o-sulfonamide benzoate.

[0110] Compared with Example 6, Example 11 uses an equal amount of commercially available activated carbon to replace adsorbent A, which has poor adsorption properties and affects the purity and whiteness of methyl o-sulfonamide benzoate.

[0111] The above is only a preferred embodiment of the present invention and does not constitute any form of limitation to the present application. Although the present application is disclosed as above in the preferred embodiment, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution.

Claims

1. A method for preparing methyl o-sulfonyl chloride benzoate from methyl o-chlorobenzoate, characterized in that: The following steps are included: (1) methyl o-chlorobenzoate and pure water are mixed, stirred, sodium thiosulfate is added, heated for reaction, and cooled to obtain a solution; (2) Add dichloroethane and pure water to a reaction kettle, stir, cool to 5-10°C, introduce chlorine gas, and dropwise add the solution obtained in step (1). Control the dropping time for 2-3h to ensure that the temperature of the reaction kettle does not exceed 15-30°C. Keep the temperature for reaction, start the vacuum pump to ensure a slight negative pressure in the reaction kettle, then add sodium thiosulfate, stir, stand for phase separation, and dry to obtain methyl o-sulfonylchlorobenzoate.

2. A method for preparing methyl o-sulfonyl chloride benzoate from methyl o-chlorobenzoate according to claim 1, characterized in that: The molar ratio of methyl o-chlorobenzoate to sodium thiosulfate in step (1) is 1:(1.2-1.6), and the mass ratio of methyl o-chlorobenzoate to pure water is 1:(2-3).

3. A method for preparing methyl o-sulfonyl chloride benzoate from methyl o-chlorobenzoate according to claim 2, characterized in that: The mass ratio of the solution, chlorine gas and pure water in step (2) is 1:(0.4-0.65):(0.004-0.008).

4. A method for preparing methyl o-sulfonamide benzoate from methyl o-chlorobenzoate, characterized in that: The following steps are included: S1. Preparation of methyl o-sulfonyl chlorobenzoate (1) methyl o-chlorobenzoate and pure water are mixed, stirred, sodium thiosulfate is added, heated for reaction, and cooled to obtain a solution; (2) adding dichloroethane and pure water to a reaction kettle, stirring, cooling to 5-10° C., introducing chlorine gas, and dripping the solution obtained in step (1), controlling the dripping time to 2-3 hours, ensuring that the temperature of the reaction kettle does not exceed 15-30° C., and then keeping the temperature for reaction, turning on the vacuum pump to ensure a slight negative pressure in the reaction kettle, and then adding sodium thiosulfate, stirring, standing for phase separation, and drying to obtain methyl o-sulfonyl chlorobenzoate; S2. Preparation of methyl o-sulfonamide benzoate Methyl o-sulfonylchlorobenzoate was added to methanol with stirring, cooled, and ammonia solution was added. The mixture was heated to 40-60° C. and reacted for 2-3 hours to generate crude methyl o-sulfonylamidebenzoate, which was purified to obtain methyl o-sulfonylamidebenzoate.

5. A method for preparing methyl o-sulfonamide benzoate from methyl o-chlorobenzoate according to claim 4, characterized in that: The ammonia solution in step S2 is a methanol solution of ammonia with a mass fraction of 15-30%.

6. A method for preparing methyl o-sulfonamide benzoate from methyl o-chlorobenzoate according to claim 4, characterized in that: The specific steps of purification in step S2 are as follows: The crude product of methyl o-sulfonamide benzoate is dissolved in toluene, heated to 85-95°C while stirring, an adsorbent is added, and stirring is continued for 1-1.5 hours; the temperature is raised to 100-105°C, filtered, naturally crystallized, filtered, and naturally dried to obtain methyl o-sulfonamide benzoate.

7. A method for preparing methyl o-sulfonamide benzoate from methyl o-chlorobenzoate according to claim 6, characterized in that: The preparation method of the adsorbent comprises the following steps: Q1. After removing impurities from beet pulp, wash it with clean water, filter it, dry it, crush it, and pass it through a 20-60 mesh sieve to obtain beet pulp powder; add distilled water, stir it, add 2-5 mol / L citric acid aqueous solution, heat it for reaction, filter it, wash it, and dry it to obtain beet pulp fiber; Q2. The beet pulp fiber obtained in step Q1 is dispersed in an aqueous sodium hydroxide solution, stirred, filtered, and the resulting residue is poured into distilled water, stirred, filtered, washed, and dried to obtain alkali-treated beet pulp fiber; Q3. The alkali-treated beet pulp fiber obtained in step Q2 is added to a reactor, and 0.1-0.2 mol / L sodium hydroxide aqueous solution and trimethylolpropane triglycidyl ether are added in sequence, heated to 50-70°C and stirred for reaction for 4-6 hours, filtered, washed, and dried to obtain an intermediate product; Q4. Disperse the intermediate product obtained in step Q3 into deionized water and soak for 30-45 minutes, then add N-tert-butyloxycarbonyl-1,2-ethylenediamine and sodium bicarbonate in sequence, heat to 60-100°C and react for 4-6 hours, filter, wash, and dry to obtain an adsorbent.

8. A method for preparing methyl o-sulfonamide benzoate from methyl o-chlorobenzoate according to claim 7, characterized in that: The ratio of the beet pulp powder to the citric acid aqueous solution in step Q1 is 1 g: (8-13) ml.

9. A method for preparing methyl o-sulfonamide benzoate from methyl o-chlorobenzoate according to claim 7, characterized in that: In step Q3, the alkali-treated beet pulp fiber, sodium hydroxide aqueous solution and trimethylolpropane triglycidyl ether are used in a ratio of 1 g: (45-55) ml: (4-6) g.

10. A method for preparing methyl o-sulfonamide benzoate from methyl o-chlorobenzoate according to any one of claims 4 to 9, characterized in that: The purity of the methyl o-sulfonamide benzoate prepared by the method is not less than 96%, and the whiteness of the methyl o-sulfonamide benzoate is not less than 92%.

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