CN116730798B - Synthesis method of triphenylchloromethane - Google Patents

Synthesis method of triphenylchloromethane Download PDF

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CN116730798B
CN116730798B CN202310043964.3A CN202310043964A CN116730798B CN 116730798 B CN116730798 B CN 116730798B CN 202310043964 A CN202310043964 A CN 202310043964A CN 116730798 B CN116730798 B CN 116730798B
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triphenylchloromethane
crystallization
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hcl gas
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CN116730798A (en
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王春民
叶新
沈文光
侯艳芝
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Jiangsu Feiyu Medical Technology Co ltd
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    • C07ORGANIC CHEMISTRY
    • C07CACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C17/00Preparation of halogenated hydrocarbons
    • C07C17/26Preparation of halogenated hydrocarbons by reactions involving an increase in the number of carbon atoms in the skeleton
    • C07C17/263Preparation of halogenated hydrocarbons by reactions involving an increase in the number of carbon atoms in the skeleton by condensation reactions
    • C07C17/266Preparation of halogenated hydrocarbons by reactions involving an increase in the number of carbon atoms in the skeleton by condensation reactions of hydrocarbons and halogenated hydrocarbons
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07CACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C17/00Preparation of halogenated hydrocarbons
    • C07C17/38Separation; Purification; Stabilisation; Use of additives
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07CACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C17/00Preparation of halogenated hydrocarbons
    • C07C17/38Separation; Purification; Stabilisation; Use of additives
    • C07C17/389Separation; Purification; Stabilisation; Use of additives by adsorption on solids
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07CACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C17/00Preparation of halogenated hydrocarbons
    • C07C17/38Separation; Purification; Stabilisation; Use of additives
    • C07C17/392Separation; Purification; Stabilisation; Use of additives by crystallisation; Purification or separation of the crystals

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Abstract

The invention belongs to the technical field of medical intermediates, and particularly relates to a synthesis method of triphenylchloromethane. The method is used for continuously producing the triphenylchloromethane, the low-toxicity and nontoxic solvent is used for replacing benzene as a crystallization solvent, so that no benzene remains in the triphenylchloromethane, and meanwhile, the triphenylmethyl alcohol is more converted into the triphenylchloromethane through the pressurizing chlorination in the recrystallization step, so that the quality of the finished product triphenylchloromethane is improved, the content of the triphenylchloromethane in the reaction solution is improved, and the crystallization yield of the triphenylchloromethane is improved. The condition that the triphenylchloromethanol is enriched in the crystallization mother liquor and gradually increases in the circulation of the crystallization mother liquor is avoided. And further, adding activated carbon into the reaction liquid to remove impurities in the crystallization mother liquor, and then applying the crystallization mother liquor to quenching reaction to realize the recycling of the mother liquor. At this time, the recrystallization solvent is mixed with pure benzene to improve the solubility of the triphenylchloromethane in the reaction liquid, so as to improve the crystallization yield of the triphenylchloromethane.

Description

Synthesis method of triphenylchloromethane
Technical Field
The invention belongs to the technical field of medical intermediates, and particularly relates to a synthesis method of triphenylchloromethane.
Background
Triphenylchloromethane is named as trityl chloride and chlorotrityl methane, is a white powder material, is easily dissolved in benzene, carbon disulfide, petroleum ether and normal hexane, is slightly dissolved in alcohol and ether, is insoluble in water, and is easy to react after water absorption to generate the trityl alcohol. The stable form of the trityl carbonium ion is easy to form in the organic synthesis reaction, is more favorable for nucleophilic substitution reaction, and plays a role in occupying space protection in the reaction, so that the trityl carbonium ion is often used as a protecting reagent for primary hydroxyl selective protecting groups, sulfhydryl groups and amino groups carried in compounds such as nucleoside, monosaccharide or polysaccharide in the pharmaceutical chemical industry field; basic chemical reagents in polypeptide synthesis; is used as intermediate of cephalosporin and antiviral agent iodate and tritylation agent.
The existing synthesis process of triphenylchloromethane mainly comprises the following steps: (1) Friedel-crafts reaction system of benzene and carbon tetrachloride, (2) triphenylmethanol chlorination method, (3) triphenylmethane chlorination method, and (4) triphenylmethyl alkyl ether chlorination method. The traditional method for producing the triphenylchloromethane adopts anhydrous aluminum trichloride as a catalyst, adopts carbon tetrachloride and pure benzene as raw materials, generates Friedel-crafts alkylation reaction to generate a complex of the triphenylchloromethane and the aluminum trichloride, and obtains the triphenylchloromethane through post-treatment such as hydrolysis, washing, filtering and decoloring, recrystallization and the like. However, benzene is used as a raw material and a reaction solvent and a crystallization solvent in the method, so that trace benzene remains in the finished triphenylchloromethane product, and the benzene can cause acute poisoning, leukemia and the like, is harmful to the environment and pollutes water. And benzene is volatile, and a large amount of volatile gas accumulates to possibly cause explosion. Therefore, in order to reduce the content of pure benzene in the system and the potential safety hazard, toluene/xylene is used as a recrystallization solvent, so that the safety of the whole system is a new trend.
In Chinese patent CN112979411A, a process for preparing triphenylchloromethane is disclosed, wherein dimethylbenzene is used as a recrystallization solvent, and the dimethylbenzene has better solubility to the triphenylchloromethane, and the recrystallization temperature is lower than 0 ℃ than that of benzene, so that the temperature is reduced by more than 10 ℃ than that of the traditional process, the phenomenon that benzene is used as a solvent to be separated out below 5.5 ℃ is avoided, the crystallization purity is improved, and the white powder of the triphenylchloromethane is finally obtained, and the content of the triphenylchloromethane is more than 99%. But this approach is superior to benzene as a recrystallization solvent due to the solubility of xylenes relative to triphenylchloromethane. The yield of triphenylchloromethane is reduced to 80% or less due to the reduction in the deposition rate of triphenylchloromethane, and in this case, since the mother liquor contains impurities such as triphenylchloromethane, monophenyl chloromethane and diphenylchloromethane, the yield of triphenylchloromethane is hardly improved even by secondary crystallization. Therefore, how to improve the crystallization yield of triphenylchloromethane and improve the safety of the system is a problem to be solved.
The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art that is known to a person skilled in the art.
Disclosure of Invention
The first object of the invention is to provide a method for synthesizing triphenylchloromethane, which uses toluene/xylene as a recrystallization solvent, and uses the crystallization mother liquor to quench reaction to realize the cyclic utilization of the mother liquor, thereby improving the crystallization yield of the triphenylchloromethane.
The technical aim of the invention is realized by the following technical scheme:
a method for synthesizing triphenylchloromethane comprises the following process steps:
s1: adding pure benzene and anhydrous aluminum trichloride into a reactor, uniformly mixing and stirring, and dropwise adding carbon tetrachloride while stirring at 10-20 ℃; after the dripping is finished, stirring is continued until the reaction is no longer exothermic, the reaction is balanced, hydrogen chloride gas is not overflowed any more, and the steam is subjected to heat preservation reaction for 2-3 hours; generating a complex of triphenylchloromethane and aluminum trichloride, and drying and collecting hydrogen chloride gas generated in the reaction process by concentrated sulfuric acid; so as to be recycled. In the step, the reaction temperature has a great influence on the synthesis of the triphenylchloromethane, the reaction is too slow due to low reaction temperature, and side reactions are increased due to too high reaction temperature, so that the reaction is ensured to be fully carried out by limiting the reaction temperature to 10-20 ℃. The reaction formula is as follows:
s2: cooling the reaction liquid after the heat preservation reaction is finished, cooling the reaction liquid to 20 ℃, adding the hydrochloric acid aqueous solution into pure benzene, mixing and stirring uniformly, dropwise adding the cooled reaction liquid for quenching reaction, controlling the reaction temperature to be below 50 ℃, stirring and standing for layering after the dropwise adding is finished, removing the water phase, and washing the oil phase with the hydrochloric acid aqueous solution for 2-3 times; the quenching reaction principle is that pure benzene is used for diluting the reaction liquid, so that the concentration of the reaction liquid is reduced, the reaction rate is reduced until the reaction does not occur any more, and the anhydrous aluminum trichloride is destroyed by the hydrochloric acid aqueous solution, so that the catalyst is invalid. The reaction solution in the step comprises the Friedel-crafts reaction solution in the step S1 and the crystallization mother solution in the step S5 of the previous working procedure, and low-toxicity toluene/xylene is used as a recrystallization solvent to continuously produce triphenylchloromethane, so that the crystallization mother solution contains a large amount of triphenylchloromethane, and even if the crystallization mother solution is recrystallized for a plurality of times, the crystallization mother solution cannot be completely recovered, and the utilization rate of materials is reduced. According to the invention, the crystallization mother liquor in the production of the previous working procedure in the continuous production process is subjected to post-treatment, so that the crystallization mother liquor contains triphenylchloromethane and less triphenylchloromethane, and then the crystallization mother liquor is mixed with the Friedel-crafts reaction liquid to participate in continuous reaction, so that the crystallization yield of the triphenylchloromethane is improved.
S3: adding anhydrous calcium chloride and activated carbon into the oil phase, introducing dry HCl gas for heat preservation reaction, performing filter pressing after the heat preservation reaction for 1-2 hours to obtain an organic phase, performing normal pressure distillation on the organic phase at the temperature of 80-100 ℃, and performing vacuum drying until no fraction exists to obtain a dry crude product; since triphenylchloromethane easily absorbs water to generate triphenylchloromethane, the invention uses HCl gas to chlorinate the triphenylchloromethane into triphenylchloromethane, and then uses anhydrous calcium chloride to remove water generated in the reaction. The reaction formula is as follows:
s4: toluene/xylene is used as a recrystallization solvent, the dried crude product obtained in the step S3 is added, anhydrous calcium chloride and active carbon are added, and the temperature of the dried HCl gas is controlled at 30 ℃ to ensure that the reaction pressure is 0.1-0.3 MPa for heat preservation reaction; in the step, the active carbon is used for adsorbing impurities, so that the impurities in the crystallization mother liquor are reduced, and more triphenylchloromethanol is converted into triphenylchloromethane through pressurization and purification, so that the quality of the finished product triphenylchloromethane is improved, the content of the triphenylchloromethane in the reaction solution is improved, and the crystallization yield of the triphenylchloromethane is improved. In the subsequent crystallization mother liquor circulation, the content of the triphenylchloromethanol in the crystallization mother liquor is reduced, the enrichment of the triphenylchloromethanol is avoided, the continuous use of the crystallization mother liquor is realized, and the crystallization yield of the triphenylchloromethane is improved.
S5: removing HCl and partial recrystallization solvent by filter pressing after the reaction is finished, and obtaining a triphenylchloromethane finished product by freeze crystallization, filter pressing, washing and vacuum drying; and adding the crystallization mother liquor into the reaction liquid in the step S2 of the next working procedure to participate in continuous reaction.
In the first preparation, the quenching reaction liquid contains pure benzene, triphenylchloromethane, monophenyl chloromethane, diphenylchloromethane and other impurities, and since the stability of trityl carbonium ions is quite high, the triphenylchloromethane is easy to react with water to generate triphenylchloromethane, so that the content of the triphenylchloromethane is reduced, and in the S3 step, the triphenylchloromethane is chlorinated into the triphenylchloromethane through HCl gas, then the water generated by the reaction is removed through anhydrous calcium chloride, and in the recrystallization step, the dry HCl gas is further introduced to chlorinate the triphenylchloromethane into the triphenylchloromethane, at the moment, the content of the triphenylchloromethane in the crystallization mother liquid is reduced, but the content of the triphenylchloromethane is still not high, and if the crystallization mother liquid is recrystallized directly, the crystallization yield of the triphenylchloromethane is low. And the crystallization mother liquor is used as a reaction liquid to be applied to the step S2 to participate in quenching reaction, is mixed with the reaction liquid generated in the step S1, is used as a reaction liquid to be added into a mixed liquid of pure benzene and hydrochloric acid aqueous solution in a dropwise manner, so that the content of triphenylchloromethane in the reaction liquid is increased, at the moment, since the reaction liquid contains pure benzene and a recrystallization solvent, triphenylchloromethane, a small amount of triphenylchloromethane and other impurities, the solubility and the safety of the recrystallization solvent are superior to those of benzene, the solubility of the mixed solution of the recrystallization solvent and benzene relative to that of the triphenylchloromethane is increased, forward progress of the chlorination reaction of the triphenylchloromethane is promoted, the content of the triphenylchloromethane in the reaction liquid is increased, and then the content of the triphenylchloromethane in the reaction liquid is increased through pressurized secondary chlorination in the recrystallization step, at the moment, freezing crystallization of the crystallization mother liquor is performed again, so that the content of the triphenylchloromethane in the reaction liquid is increased, and the crystallization yield of the triphenylchloromethane is increased.
Preferably, the HCl gas tank includes a first gas tank for continuously performing the gas supply in step S4 and obtaining a relative pressure range of HCl gas by a length of the receiving time and a volume range of the HCl gas tank, and a second gas tank for collecting HCl gas generated during the reaction in step S1 and continuously performing the gas supply to the first gas tank. In the step S4, toluene/xylene is used as a recrystallization solvent, and the precipitation amount of triphenylchloromethane is lower than that of benzene at the moment as the recrystallization solvent.
Preferably, in step S1, the weight ratio of carbon tetrachloride, pure benzene and anhydrous aluminum trichloride is 1: 5-15: 1.1 to 2. In the reaction process, anhydrous aluminum trichloride and triphenylchloromethane form a 1:1 complex, so that at least 1 equivalent of anhydrous aluminum trichloride is required to be consumed theoretically, and the full reaction is ensured by limiting the content of the anhydrous aluminum trichloride. Pure benzene and carbon tetrachloride are subjected to Friedel-crafts reaction under the catalysis of anhydrous aluminum trichloride to generate triphenylchloromethane and release hydrogen chloride gas, and in the process, the pure benzene is used as a reactant and a reaction solvent at the same time, so that the utilization rate of raw materials is improved, the forward progress of Friedel-crafts reaction can be ensured, and the reaction yield and the purity of the triphenylchloromethane are improved.
Preferably, in step S1, the temperature of the steam is 70 to 80 ℃. The reaction temperature is increased, the generation of byproducts is reduced, and the purity and the yield of the product are improved.
Preferably, in the step S2, the mass ratio of the reaction solution to the pure benzene is 1:0.6-0.8, and the mass ratio of the reaction solution to the hydrochloric acid aqueous solution is 1:0.8-0.9. The reaction liquid is diluted by pure benzene, the concentration of the pure benzene in the reaction liquid is controlled to be 60% -80%, so that the concentration of the reaction liquid is reduced, the reaction rate is further reduced until the reaction does not occur any more, meanwhile, the anhydrous aluminum trichloride and triphenylchloromethane form a 1:1 complex in the reaction process, and the catalyst is disabled by controlling the mass ratio of the reaction liquid to the hydrochloric acid aqueous solution to be 1:0.8-0.9 and destroying the anhydrous aluminum trichloride by the hydrochloric acid aqueous solution.
Preferably, in the step S3, the content of anhydrous calcium chloride is 2% -5% of the weight of the oil phase; the content of the activated carbon is 0.2% -0.4% of the weight of the oil phase. The anhydrous calcium chloride is used for absorbing water generated in the chlorination reaction of the triphenylchloromethanol, and the activated carbon is mainly used for adsorbing impurities in the reaction liquid, so that the crystallization mother liquid can be recycled.
Preferably, in the step S4, the weight ratio of the dried crude product to the recrystallization solvent is 1:1-3. And the dried crude product is controlled to be completely immersed in the recrystallization solvent, so that the crystallization yield of the target product is improved.
Preferably, in step S5, the temperature of the freeze crystallization is-10 to 0 ℃. In the invention, the melting point of toluene is-95 ℃, the melting point of dimethylbenzene is-34 ℃, and the crystallinity of triphenylchloromethane is ensured by controlling the temperature of freezing crystallization below 0 ℃.
Preferably, after freezing and crystallizing for 2-4 hours, filtering and pressing by utilizing nitrogen, washing by using dimethylbenzene, and drying in vacuum at 50 ℃ until the weight is constant, thus obtaining the white triphenylchloromethane powder.
In summary, the invention has the following beneficial effects:
(1) The invention uses low-toxicity and nontoxic solvent to replace benzene as crystallization solvent, so that no benzene residue exists in triphenylchloromethane, and the harm to human body and environment and the pollution to water body are greatly reduced. Meanwhile, the pressurizing chlorination is carried out through the recrystallization step, so that more triphenylmethyl alcohol can be converted into triphenylchloromethane, the quality of the finished triphenylchloromethane product is improved, the content of the triphenylchloromethane in the reaction liquid is improved, and the crystallization yield of the triphenylchloromethane is improved. The condition that the triphenylchloromethanol is enriched in the crystallization mother liquor and gradually increases in the circulation of the crystallization mother liquor is avoided. And further, adding activated carbon into the reaction liquid to remove impurities in the crystallization mother liquid, and adding the crystallization mother liquid into the reaction liquid for quenching reaction to realize the recycling of the mother liquid. At this time, the recrystallization solvent is mixed with pure benzene, so that the solubility of the triphenylchloromethane in the reaction liquid is improved, and the content of the triphenylchloromethane in the quenching reaction oil phase is improved, so that the crystallization yield of the triphenylchloromethane is improved. Compared with the prior art, the method has the advantages of advanced process route, mild reaction conditions, safe and simple operation, environmental friendliness, less three wastes and the like.
(2) According to the invention, the first gas storage tank and the second gas storage tank are arranged, the HCl gas in the first gas storage tank is controlled to be used for continuously executing the gas supply in the step S4, and the second gas storage tank is used for collecting the HCl gas generated in the reaction process of the step S1 and continuously replenishing the gas to the first gas storage tank. Therefore, the internal pressure of the first gas storage tank is balanced, and the first gas storage tank is controlled to participate in the heat preservation reaction in the recrystallization step in a stable pressure state, so that HCl gas can be absorbed better in the process of reaction balance, and the crystallization yield of triphenylchloromethane is improved. Compared with the prior art, the invention not only reduces pollution, but also improves the recycling of resources, and has great economic value.
Detailed Description
In order to further describe the technical means and effects adopted by the invention to achieve the preset aim, the invention provides a synthesis method of triphenylchloromethane, and specific embodiments, characteristics and effects thereof are described in detail below.
The sources of the raw materials used in the examples:
example 1
A method for synthesizing triphenylchloromethane comprises the following process steps:
s1: 120g of pure benzene and 30g of anhydrous aluminum trichloride are put into a 500mL four-necked flask, mixed and stirred uniformly, 25g of carbon tetrachloride is added dropwise under stirring at 20 ℃ for 2.5h; continuously stirring until the reaction is not exothermic after the dripping is finished, performing steam heat preservation reaction for 2 hours, and drying and collecting HCl gas generated in the reaction process into a second gas storage tank; the HCl gas in the first gas storage tank is used for continuously executing the gas supply in the step S4, the relative pressure range of the HCl gas is obtained through the length of the receiving time and the volume range of the receiving time, and the second gas storage tank is used for collecting the HCl gas generated in the reaction process of the step S1 and continuously supplying the gas to the first gas storage tank.
S2: cooling the Friedel-crafts reaction liquid after the heat preservation reaction is finished, so that the Friedel-crafts reaction liquid is cooled to 20 ℃, and introducing the crystallization mother liquor produced in the last step to uniformly mix with the Friedel-crafts reaction liquid, namely the reaction liquid; adding 150g of hydrochloric acid aqueous solution (15%) into 110g of pure benzene, uniformly mixing and stirring, dropwise adding the cooled reaction solution for quenching reaction, controlling the dropwise adding time to be 1h, controlling the reaction temperature to be below 50 ℃, stirring for 0.5h after dropwise adding, standing for layering, removing the water phase, and washing the oil phase with the hydrochloric acid aqueous solution for 3 times;
s3: adding 2g of active carbon and 15g of anhydrous calcium chloride into the oil phase, introducing dry HCl gas, carrying out pressure filtration after reacting for 1h at a temperature of 80 ℃ to obtain an organic phase, carrying out normal pressure distillation on the organic phase until no fraction exists, and carrying out vacuum drying to obtain a dry crude product;
s4: adding the dried crude product obtained in the step S3 into a xylene solution according to the proportion of 1:1.3, adding 2g of active carbon and 12g of anhydrous calcium chloride, controlling the temperature at 30 ℃, introducing dry HCl gas for 1h, and ensuring the reaction pressure to be 0.2MPa for heat preservation reaction;
s5: removing HCl and part of dimethylbenzene after the reaction is finished, performing heat filtration, freezing and crystallizing for 4 hours at the temperature of minus 10 ℃, performing pressure filtration by using nitrogen, washing by using dimethylbenzene, and performing vacuum drying at the temperature of 50 ℃ to constant weight to obtain white powder, wherein the content of triphenylchloromethane in a final product is 99.6%, and the yield is 90.1%.
Example 2
A method for synthesizing triphenylchloromethane comprises the following process steps:
s1: 150g of pure benzene and 40g of anhydrous aluminum trichloride are put into a 500mL four-necked flask, mixed and stirred uniformly, 25g of carbon tetrachloride is added dropwise under stirring at 20 ℃ for 2.5h; continuously stirring until the reaction is not exothermic after the dripping is finished, performing steam heat preservation reaction for 2 hours, and drying and collecting HCl gas generated in the reaction process into a second gas storage tank; the HCl gas in the first gas storage tank is used for continuously executing the gas supply in the step S4, the relative pressure range of the HCl gas is obtained through the length of the receiving time and the volume range of the receiving time, and the second gas storage tank is used for collecting the HCl gas generated in the reaction process of the step S1 and continuously supplying the gas to the first gas storage tank.
S2: cooling the Friedel-crafts reaction liquid after the heat preservation reaction is finished, so that the Friedel-crafts reaction liquid is cooled to 20 ℃, and introducing the crystallization mother liquor produced in the last step to uniformly mix with the Friedel-crafts reaction liquid, namely the reaction liquid; adding 170g of hydrochloric acid aqueous solution (15%) into 150g of pure benzene, uniformly mixing and stirring, dropwise adding the cooled reaction solution for quenching reaction, controlling the dropwise adding time to be 1h, controlling the reaction temperature to be below 50 ℃, stirring for 0.5h after dropwise adding, standing for layering, removing the water phase, and washing the oil phase with the hydrochloric acid aqueous solution for 3 times;
s3: adding 3g of active carbon and 15g of anhydrous calcium chloride into the oil phase, introducing dry HCl gas, carrying out pressure filtration after reacting for 1h at a temperature of 80 ℃ to obtain an organic phase, carrying out normal pressure distillation on the organic phase until no fraction exists, and carrying out vacuum drying to obtain a dry crude product;
s4: adding the dried crude product obtained in the step S3 into toluene solution according to the proportion of 1:1.3, adding 2g of active carbon and 15g of anhydrous calcium chloride, controlling the temperature at 30 ℃, and introducing dry HCl gas for 1h for heat preservation reaction; ensuring the reaction pressure to be 0.2MPa for heat preservation reaction;
s5: removing HCl and part of toluene after the reaction is finished, performing heat filtration, freezing and crystallizing for 4 hours at the temperature of minus 10 ℃, performing pressure filtration by using nitrogen, washing by using dimethylbenzene, and performing vacuum drying to constant weight at the temperature of 50 ℃ to obtain white powder, wherein the content of triphenylchloromethane in the final product is 99.3%, and the yield is 88.9%.
Example 3
A method for synthesizing triphenylchloromethane comprises the following process steps:
s1: 140g of pure benzene and 30g of anhydrous aluminum trichloride are put into a 500mL four-necked flask, and are uniformly mixed and stirred, 25g of carbon tetrachloride is dropwise added under stirring at 20 ℃ for 2.5h; continuously stirring until the reaction is not exothermic after the dripping is finished, performing steam heat preservation reaction for 2 hours, and drying and collecting HCl gas generated in the reaction process into a second gas storage tank; the HCl gas in the first gas storage tank is used for continuously executing the gas supply in the step S4, the relative pressure range of the HCl gas is obtained through the length of the receiving time and the volume range of the receiving time, and the second gas storage tank is used for collecting the HCl gas generated in the reaction process of the step S1 and continuously supplying the gas to the first gas storage tank.
S2: cooling the Friedel-crafts reaction liquid after the heat preservation reaction is finished, so that the Friedel-crafts reaction liquid is cooled to 20 ℃, and introducing the crystallization mother liquor produced in the last step to uniformly mix with the Friedel-crafts reaction liquid, namely the reaction liquid; adding 150g of hydrochloric acid aqueous solution (15%) into 140g of pure benzene, uniformly mixing and stirring, dropwise adding the cooled reaction solution for quenching reaction, controlling the dropwise adding time to be 1h, controlling the reaction temperature to be below 50 ℃, stirring for 0.5h after dropwise adding, standing for layering, removing the water phase, and washing the oil phase with the hydrochloric acid aqueous solution for 3 times;
s3: adding 3g of active carbon and 15g of anhydrous calcium chloride into the oil phase, introducing dry HCl gas, carrying out pressure filtration after reacting for 1h at a temperature of 80 ℃ to obtain an organic phase, carrying out normal pressure distillation on the organic phase until no fraction exists, and carrying out vacuum drying to obtain a dry crude product;
s4: adding the dried crude product obtained in the step S3 into a xylene solution according to the proportion of 1:1.3, adding 2g of active carbon and 15g of anhydrous calcium chloride, controlling the temperature at 30 ℃, introducing dry HCl gas for 1h, and ensuring the reaction pressure to be 0.1MPa for heat preservation reaction;
s5: removing HCl and part of dimethylbenzene after the reaction is finished, performing heat filtration, freezing and crystallizing for 4 hours at the temperature of minus 10 ℃, performing pressure filtration by using nitrogen, washing by using dimethylbenzene, and performing vacuum drying to constant weight at the temperature of 50 ℃ to obtain white powder, wherein the content of triphenylchloromethane in a final product is 99.4%, and the yield is 89.6%.
Example 4
A method for synthesizing triphenylchloromethane comprises the following process steps:
s1: 300g of pure benzene and 50g of anhydrous aluminum trichloride are put into a 500mL four-necked flask, mixed and stirred uniformly, 25g of carbon tetrachloride is added dropwise under stirring at 20 ℃ for 2.5h; continuously stirring until the reaction is not exothermic after the dripping is finished, performing steam heat preservation reaction for 2 hours, and drying and collecting HCl gas generated in the reaction process into a second gas storage tank; the HCl gas in the first gas storage tank is used for continuously executing the gas supply in the step S4, the relative pressure range of the HCl gas is obtained through the length of the receiving time and the volume range of the receiving time, and the second gas storage tank is used for collecting the HCl gas generated in the reaction process of the step S1 and continuously supplying the gas to the first gas storage tank.
S2: cooling the Friedel-crafts reaction liquid after the heat preservation reaction is finished, so that the Friedel-crafts reaction liquid is cooled to 20 ℃, and introducing the crystallization mother liquor produced in the last step to uniformly mix with the Friedel-crafts reaction liquid, namely the reaction liquid; adding 270g of hydrochloric acid aqueous solution (15%) into 250g of pure benzene, uniformly mixing and stirring, dropwise adding the cooled reaction solution for quenching reaction, controlling the dropwise adding time to be 1h, controlling the reaction temperature to be below 50 ℃, stirring for 0.5h after dropwise adding, standing for layering, removing the water phase, and washing the oil phase with the hydrochloric acid aqueous solution for 3 times;
s3: adding 5g of active carbon and 25g of anhydrous calcium chloride into the oil phase, introducing dry HCl gas, carrying out pressure filtration after reacting for 1h at a temperature of 80 ℃ to obtain an organic phase, carrying out normal pressure distillation on the organic phase until no fraction exists, and carrying out vacuum drying to obtain a dry crude product;
s4: adding the dried crude product obtained in the step S3 into a xylene solution according to the proportion of 1:1.3, adding 5g of active carbon and 30g of anhydrous calcium chloride, controlling the temperature at 30 ℃, introducing dry HCl gas for 1h, and ensuring the reaction pressure to be 0.1MPa for heat preservation reaction;
s5: removing HCl and part of dimethylbenzene after the reaction is finished, performing heat filtration, freezing and crystallizing for 4 hours at the temperature of minus 10 ℃, performing pressure filtration by using nitrogen, washing by using dimethylbenzene, and performing vacuum drying at the temperature of 50 ℃ to constant weight to obtain white powder, wherein the content of triphenylchloromethane in a final product is 99.3%, and the yield is 88.3%.
Comparative example 1
A method for synthesizing triphenylchloromethane comprises the following process steps:
s1: 120g of pure benzene and 30g of anhydrous aluminum trichloride are put into a 500mL four-necked flask, mixed and stirred uniformly, 25g of carbon tetrachloride is added dropwise under stirring at 20 ℃ for 2.5h; continuously stirring until the reaction is not exothermic after the dripping is finished, performing steam heat preservation reaction for 2 hours, and drying and collecting HCl gas generated in the reaction process into a second gas storage tank; the HCl gas in the first gas storage tank is used for continuously executing the gas supply in the step S4, the relative pressure range of the HCl gas is obtained through the length of the receiving time and the volume range of the receiving time, and the second gas storage tank is used for collecting the HCl gas generated in the reaction process of the step S1 and continuously supplying the gas to the first gas storage tank.
S2: cooling the reaction liquid after the heat preservation reaction is finished, cooling the reaction liquid to 20 ℃, adding 150g of hydrochloric acid aqueous solution (15%) into 110g of pure benzene, mixing and stirring uniformly, dropwise adding the cooled reaction liquid for quenching reaction for 1h, controlling the reaction temperature to be below 50 ℃, stirring for 0.5h after the dropwise adding is finished, standing for layering, removing the water phase, and washing the oil phase with the hydrochloric acid aqueous solution for 3 times;
s3: adding 2g of active carbon and 15g of anhydrous calcium chloride into the oil phase, introducing dry HCl gas, carrying out pressure filtration after reacting for 1h at a temperature of 80 ℃ to obtain an organic phase, carrying out normal pressure distillation on the organic phase until no fraction exists, and carrying out vacuum drying to obtain a dry crude product;
s4: adding the dried crude product obtained in the step S3 into pure benzene according to the proportion of 1:1.3, adding 2g of active carbon and 12g of anhydrous calcium chloride, controlling the temperature at 30 ℃, introducing dry HCl gas for 1h, and ensuring the reaction pressure to be 0.2MPa for heat preservation reaction;
s5: removing HCl and part of dimethylbenzene after the reaction is finished, performing heat filtration, freezing and crystallizing for 4 hours at the temperature of minus 10 ℃, performing pressure filtration by using nitrogen, washing by using dimethylbenzene, and performing vacuum drying to constant weight at the temperature of 50 ℃ to obtain white powder, wherein the content of triphenylchloromethane in a final product is 99.2%, and the yield is 89.3%.
Comparative example 2
A method for synthesizing triphenylchloromethane comprises the following process steps:
s1: 120g of pure benzene and 30g of anhydrous aluminum trichloride are put into a 500mL four-necked flask, mixed and stirred uniformly, 25g of carbon tetrachloride is added dropwise under stirring at 20 ℃ for 2.5h; continuously stirring until the reaction is not exothermic after the dripping is finished, performing steam heat preservation reaction for 2 hours, and drying and collecting HCl gas generated in the reaction process into a second gas storage tank; the HCl gas in the first gas storage tank is used for continuously executing the gas supply in the step S4, the relative pressure range of the HCl gas is obtained through the length of the receiving time and the volume range of the receiving time, and the second gas storage tank is used for collecting the HCl gas generated in the reaction process of the step S1 and continuously supplying the gas to the first gas storage tank.
S2: cooling the reaction liquid after the heat preservation reaction is finished, cooling the reaction liquid to 20 ℃, adding 150g of hydrochloric acid aqueous solution (15%) into 110g of pure benzene, mixing and stirring uniformly, dropwise adding the cooled reaction liquid for quenching reaction for 1h, controlling the reaction temperature to be below 50 ℃, stirring for 0.5h after the dropwise adding is finished, standing for layering, removing the water phase, and washing the oil phase with the hydrochloric acid aqueous solution for 3 times;
s3: adding 2g of active carbon and 15g of anhydrous calcium chloride into the oil phase, introducing dry HCl gas, carrying out pressure filtration after reacting for 1h at a temperature of 80 ℃ to obtain an organic phase, carrying out normal pressure distillation on the organic phase until no fraction exists, and carrying out vacuum drying to obtain a dry crude product;
s4: adding the dried crude product obtained in the step S3 into a xylene solution according to the proportion of 1:1.3, adding 2g of active carbon and 12g of anhydrous calcium chloride, controlling the temperature at 30 ℃, introducing dry HCl gas for 1h, and ensuring the reaction pressure to be 0.2MPa for heat preservation reaction;
s5: removing HCl and part of dimethylbenzene after the reaction is finished, performing heat filtration, freezing and crystallizing for 4 hours at the temperature of minus 10 ℃, performing pressure filtration by using nitrogen, washing by using dimethylbenzene, and performing vacuum drying at the temperature of 50 ℃ to constant weight to obtain white powder, wherein the content of triphenylchloromethane in a final product is 99.6%, and the yield is 78.1%.
Comparative example 3
A method for synthesizing triphenylchloromethane comprises the following process steps:
s1: 120g of pure benzene and 30g of anhydrous aluminum trichloride are put into a 500mL four-necked flask, mixed and stirred uniformly, 25g of carbon tetrachloride is added dropwise under stirring at 20 ℃ for 2.5h; after the dripping is finished, stirring is continued until the reaction is no longer exothermic, and the steam is kept for 2 hours;
s2: cooling the reaction liquid after the heat preservation reaction is finished, cooling the reaction liquid to 20 ℃, adding 150g of hydrochloric acid aqueous solution (15%) into 110g of pure benzene, mixing and stirring uniformly, dropwise adding the cooled reaction liquid for quenching reaction for 1h, controlling the reaction temperature to be below 50 ℃, stirring for 0.5h after the dropwise adding is finished, standing for layering, removing the water phase, and washing the oil phase with the hydrochloric acid aqueous solution for 3 times;
s3: adding 15g of anhydrous calcium chloride into the oil phase, introducing dry HCl gas, carrying out pressure filtration after reacting for 1h at a temperature of 80 ℃ to obtain an organic phase, carrying out normal pressure distillation on the organic phase until no fraction exists, and carrying out vacuum drying to obtain a dried crude product;
s4: adding the dried crude product obtained in the step S3 into a xylene solution according to the proportion of 1:1.3, adding 2g of active carbon and 12g of anhydrous calcium chloride, controlling the temperature at 30 ℃, and introducing dry HCl gas for 1h for heat preservation reaction;
s5: removing HCl and part of dimethylbenzene after the reaction is finished, performing heat filtration, freezing and crystallizing for 4 hours at the temperature of minus 10 ℃, performing pressure filtration by using nitrogen, washing by using dimethylbenzene, and performing vacuum drying at the temperature of 50 ℃ to constant weight to obtain white powder, wherein the content of triphenylchloromethane in a final product is 99.1%, and the yield is 76.1%.
Comparative example 4
A method for synthesizing triphenylchloromethane comprises the following process steps:
s1: 120g of pure benzene and 30g of anhydrous aluminum trichloride are put into a 500mL four-necked flask, mixed and stirred uniformly, 25g of carbon tetrachloride is added dropwise under stirring at 20 ℃ for 2.5h; after the dripping is finished, stirring is continued until the reaction is not exothermic, the steam is used for heat preservation reaction for 2 hours, and HCl gas generated in the reaction process is dried and collected into a HCl gas storage tank;
s2: cooling the reaction liquid after the heat preservation reaction is finished, cooling the reaction liquid to 20 ℃, adding 150g of hydrochloric acid aqueous solution (15%) into 110g of pure benzene, mixing and stirring uniformly, dropwise adding the cooled reaction liquid for quenching reaction for 1h, controlling the reaction temperature to be below 50 ℃, stirring for 0.5h after the dropwise adding is finished, standing for layering, removing the water phase, and washing the oil phase with the hydrochloric acid aqueous solution for 3 times;
s3: the oil phase is steamed and dissolved into paste, 194.8 g of thionyl chloride is dripped, the reaction is carried out for 1h at 60 ℃, the excessive thionyl chloride is steamed and removed by heating, 200g of recrystallization solvent is added for dissolution, the recrystallization solvent is toluene, the cooling crystallization and the suction filtration are carried out at 10 ℃, the filter cake is dried to constant weight under vacuum at 50 ℃ to obtain white powder, the content of triphenylchloromethane in the final product is 99.5%, and the yield is 85.3%.
Description of Performance results
As can be seen from the above examples 1-4, the invention uses low-toxicity and nontoxic solvent to replace benzene as crystallization solvent, so that no benzene residue exists in triphenylchloromethane, and the harm to human body and environment and the pollution to water body are greatly reduced. Meanwhile, the content of the triphenylchloromethane in the crystallization mother liquor is improved and the crystallization yield of the triphenylchloromethane is improved through pressurizing and secondary chlorination treatment by using dry hydrogen chloride gas in the recrystallization step. And the mother liquor is further recycled by applying the crystallization mother liquor to quenching reaction, so that the secondary crystallization yield of the triphenylchloromethane is improved.
Comparative example 1 compared with example 1, using pure benzene as a recrystallization solvent, the content of triphenylchloromethane in the final product was found to be 99.2%, and the yield was found to be 89.3%. The crystallization yield of the triphenylchloromethane in the step S6 is similar to that of the invention, which shows that the invention uses a low-toxicity and nontoxic solvent to replace benzene as a crystallization solvent, achieves the same effect as that of pure benzene as a reactant, a reaction solvent and a recrystallization solvent, and ensures that no benzene remains in the triphenylchloromethane, thereby being environment-friendly.
Comparative example 2 showed that the content of triphenylchloromethane in the final product was 99.2% and the yield was 79.1% by only one recrystallization, relative to example 1. The yield is reduced by 11% compared with the triphenylchloromethane in the step S6 in the invention. It was demonstrated that xylene has a better solubility for triphenylchloromethane, so that its crystallization yield as a recrystallization solvent for triphenylchloromethane is weaker than that for pure benzene, and thus if it is recrystallized only once, the crystallization yield of triphenylchloromethane is lower than that of example 1.
Comparative example 3 the hydrogen chloride gas generated by the friedel-crafts reaction was not collected to the supply balance in step S4, and the recrystallization reaction in step S4 was carried out at normal pressure while the yield was reduced by 14% from that of triphenylchloromethane in example 1 by only one crystallization. As is clear from the combination of comparative example 2, the crystallization yield of p-triphenylchloromethane, which is a recrystallization solvent, is weaker than that of pure benzene, and the pressure in the hydrogen chloride gas storage tank is smaller and smaller during the recrystallization process, so that the reaction progress is reduced when the recrystallization reaction is in a state of being balanced, and the crystallization yield of the triphenylchloromethane is reduced.
Comparative example 4 was compared with example 1, using thionyl chloride as a recrystallization solvent and only one recrystallization, and it was found that the yield was reduced by 4% from that of triphenylchloromethane in example 1. The sulfoxide chloride process is widely used in organic synthesis as a traditional production process. However, the tail gas generated by the thionyl chloride contains a large amount of sulfur dioxide, and the sulfur dioxide is one of six indexes of national environmental protection and strict control on the atmosphere, and has difficult treatment and large toxicity. Does not meet the requirements of green environmental protection.
It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, and that the above embodiments and descriptions are merely illustrative of the principles of the present invention, and various changes and modifications may be made without departing from the spirit and scope of the invention, which is defined in the appended claims. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims (8)

1. The synthesis method of triphenylchloromethane for continuously producing triphenylchloromethane is characterized by comprising the following process steps of:
s1: pure benzene and anhydrous aluminum trichloride are put into a reactor to undergo Friedel-crafts reaction with carbon tetrachloride and keep warm, and HCl gas generated in the reaction process is dried and collected into an HCl gas storage tank;
s2: cooling the reaction liquid after the heat preservation reaction is finished, cooling the reaction liquid to 20 ℃, adding the hydrochloric acid aqueous solution into pure benzene, mixing and stirring uniformly, dropwise adding the cooled reaction liquid for quenching reaction, controlling the reaction temperature to be below 50 ℃, stirring and standing for layering after the dropwise adding is finished, removing the water phase, and washing the oil phase with the hydrochloric acid aqueous solution for 2-3 times; the reaction liquid comprises Friedel-crafts reaction liquid in the step S1 and crystallization mother liquid in the step S5 of the previous working procedure;
s3: adding anhydrous calcium chloride and active carbon into the oil phase, introducing dry HCl gas for heat preservation reaction, performing filter pressing after the heat preservation reaction, distilling at normal pressure, and vacuum drying to obtain a dry crude product;
s4: toluene or xylene is used as a recrystallization solvent, the dried crude product obtained in the step S3 is added, anhydrous calcium chloride and activated carbon are added, and dry HCl gas is introduced to ensure that the reaction pressure is kept at 0.1MPa to 0.3MPa for reaction;
s5: removing HCl and partial recrystallization solvent by filter pressing after the reaction is finished, and obtaining a triphenylchloromethane finished product by freeze crystallization, filter pressing, washing and vacuum drying; adding the crystallization mother liquor into the reaction liquid in the step S2 of the next working procedure to participate in continuous reaction;
the HCl gas storage tank comprises a first gas storage tank and a second gas storage tank, wherein the HCl gas in the first gas storage tank is used for continuously executing the gas supply in the step S4, and the second gas storage tank is used for collecting the HCl gas generated in the reaction process of the step S1 and continuously replenishing the gas to the first gas storage tank.
2. The method for synthesizing triphenylchloromethane according to claim 1, wherein in the step S1, pure benzene and anhydrous aluminum trichloride are put into a reactor to be mixed and stirred uniformly, and carbon tetrachloride is added dropwise while stirring at 10-20 ℃; and after the dripping is finished, stirring is continued until the reaction is not exothermic, and steam heat preservation reaction is carried out for 2-3 h at 70-80 ℃.
3. The method for synthesizing triphenylchloromethane according to claim 1 or 2, wherein in the step S1, the weight ratio of carbon tetrachloride to benzene to anhydrous aluminum trichloride is 1: 5-15: 1.1 to 2.
4. The method for synthesizing triphenylchloromethane according to claim 1, wherein in the step S2, the mass ratio of the reaction solution to the pure benzene is 1:0.6-0.8, and the mass ratio of the reaction solution to the hydrochloric acid aqueous solution is 1:0.8-0.9.
5. The method for synthesizing triphenylchloromethane according to claim 1, wherein in the step S3, anhydrous calcium chloride and active carbon are added into an oil phase, dry HCl gas is introduced for heat preservation reaction, filter pressing is carried out after the heat preservation reaction is carried out for 1-2 hours, an organic phase is obtained, normal pressure distillation is carried out on the organic phase at the temperature of 80-100 ℃, and vacuum drying is carried out until no fraction exists, so that a dry crude product is obtained.
6. The method for synthesizing triphenylchloromethane according to claim 1 or 5, wherein in the step S3, the content of anhydrous calcium chloride is 2% -5% of the weight of the oil phase; the content of the activated carbon is 0.2% -0.4% of the weight of the oil phase.
7. The method for synthesizing triphenylchloromethane according to claim 1, wherein in the step S4, the weight ratio of the dried crude product to the recrystallization solvent is 1:1-3.
8. The method for synthesizing triphenylchloromethane according to claim 1, wherein in the step S5, the temperature of the freezing crystallization is-10-0 ℃.
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CN101626997A (en) * 2006-12-05 2010-01-13 塔特和莱利技术有限公司 The recovery of trityl chloride
CN102718624A (en) * 2012-06-21 2012-10-10 台州市华南医化有限公司 Method for synthesizing triphenylchloromethane
CN110204413A (en) * 2019-06-05 2019-09-06 临海市华南化工有限公司 It is a kind of to prepare triphenylchloromethane recycled technique
CN112979411A (en) * 2021-03-09 2021-06-18 江西华飞医药科技有限公司 Process for preparing triphenylchloromethane

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101626997A (en) * 2006-12-05 2010-01-13 塔特和莱利技术有限公司 The recovery of trityl chloride
CN102718624A (en) * 2012-06-21 2012-10-10 台州市华南医化有限公司 Method for synthesizing triphenylchloromethane
CN110204413A (en) * 2019-06-05 2019-09-06 临海市华南化工有限公司 It is a kind of to prepare triphenylchloromethane recycled technique
CN113748099A (en) * 2019-06-05 2021-12-03 临海市华南化工有限公司 Preparation method of triphenylchloromethane
CN112979411A (en) * 2021-03-09 2021-06-18 江西华飞医药科技有限公司 Process for preparing triphenylchloromethane

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