Process for producing methanesulfonic acid

A technology of methanesulfonic acid and hydrochloric acid, applied in the preparation of sulfate, organic chemistry and other directions, can solve the problems of adverse effects of industrialization process, difficult separation of calcium sulfate, poor operation safety, etc., and achieves easy industrialized safe production, simple separation, small investment

Active Publication Date: 2008-07-16
HEBEI YANUO CHEM IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in order to reduce production costs, the ammonia used needs to be recovered and recycled, the operation safety is poor, and the separation of the by-product calcium sulfate (gypsum) is difficult, resulting in a long process and complicated equipment, which has a negative impact on the industrialization of the process.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Add 1000 grams of water and 252 grams (2 mol) of anhydrous sodium sulfite to a 2-liter four-neck round-bottomed flask equipped with electric stirring, constant pressure dropping funnel, reflux condenser, tail gas absorption device and thermometer, and slowly heat to 50°C And stir, after the sodium sulfite is completely dissolved, the pH value of the measured solution should be 6.5 to 7.8, otherwise use dilute acid (such as about 10% sulfuric acid) or dilute alkali (such as about 10% sodium hydroxide) solution to adjust the pH value to the above range. Then the solution was rapidly heated to 90° C., 126.1 grams (1 mol) of dimethyl sulfate was added dropwise within 1 hour, and the reaction was continued for 4 hours after the dropwise addition. The reaction solution was evaporated and concentrated under reduced pressure until the sodium methanesulfonate was nearly saturated, and about 500ml of water was distilled out at this time. Then, the concentrated reaction solution ...

Embodiment 2

[0026] Add 1000 grams of water and 252 grams (2 mol) of anhydrous sodium sulfite successively to a 2-liter four-neck round bottom flask equipped with electric stirring, constant pressure dropping funnel, reflux condensation, tail gas absorption device and thermometer, slowly heat to 50 °C and Stir, and after the sodium sulfite is completely dissolved, the pH value of the measured solution should be 6.5-7.8, otherwise use dilute acid (such as about 10% sulfuric acid) or dilute alkali (such as about 10% sodium hydroxide) solution to adjust the pH value to the above scope. Then the solution was rapidly heated to 90° C., and 126.1 g (1 mol) of dimethyl sulfate was added dropwise within 1.5 hours, and the reaction was continued for 4 hours after the dropwise addition. Evaporate and concentrate the reaction solution under reduced pressure until the sodium methanesulfonate is close to saturation (approximately 500ml of water is evaporated), add a salt-removing agent-sodium chloride (...

Embodiment 3

[0028] Add 1000 grams of water and 252 grams (2 mol) of anhydrous sodium sulfite to a 2-liter four-necked round-bottomed flask equipped with electric stirring, constant pressure dropping funnel, reflux condenser, tail gas absorption device and thermometer, and slowly heat to 50°C And stir, after the sodium sulfite is completely dissolved, the pH value of the measured solution should be 6.5-7.8, otherwise use dilute acid (such as about 10% sulfuric acid) or dilute alkali (such as about 10% sodium hydroxide) solution to adjust the pH value to the above range. Then the solution was rapidly heated to 90° C., and 126.1 grams (1 mol) of dimethyl sulfate was started to be added dropwise, which took about 2 hours, and the reaction was continued for 5 hours after the dropwise addition. Evaporate and concentrate the reaction solution until the sodium methanesulfonate is nearly saturated, add a salt-removing agent-sodium chloride (about 135 grams) to saturation while it is hot, and then ...

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PUM

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Abstract

The invention discloses a preparation method for methanesulfonic acid. A water liquor or a solid mixture of a sulfite or a mixture of the sulfite and a bisulfite is reacted with a dimethyl sulfate to generate a methylsulfonate and a sulfate, and the mixture liquor of the reaction directly cools and precipitates a sulfate salt crystallization through concentration by adding a salting-out agent or a concentrated liquor; filtering and removing a dilute-methyl sulfonate liquor of the sulfate; a soluble alkaline earth salt can also be reused as a precipitant for further removing the remained sulfate ion; finally, the purified methylsulfonate liquor is concentrated to pulpiness or dry powder to be acidified by excess concentrated hydrochloric acid or excess hydrogen chloride gas is directly pumped in the purified methylsulfonate liquor to precipitate a sodium chloride crystallization. After filtering, the mixed acid liquor of hydrochloride and methanesulfonic acid can be gotten, which can get the highly-purified methanesulfonic acid after evaporation concentration, vacuum distillation and distillation. The materials of the invention can be gotten easily and the invention has simple techniques and low cost, which does no harm to the environment and is suitable to be used in industry.

Description

technical field [0001] The invention relates to a preparation method of methanesulfonic acid, which belongs to the technical field of organic synthesis in the chemical industry. Background technique [0002] In the chemical industry, methanesulfonic acid is mainly used as an intermediate in the synthesis of pesticides, medicines, and fine chemicals, and is also widely used in the electronics and electroplating industries. There are many processes for preparing methanesulfonic acid, such as methanesulfonyl chloride hydrolysis (US 4,859,373), methane sulfonation (US 2,493,038), methyl thiocyanate oxidation (SU 1,313,853), methylmercaptan oxidation (US 3,392,095; US4,239,696; GB 1,350,328), dimethyl disulfide oxidation (US 2,697,722; US3,509,206; US 3,948,922; GB 1,350,328), halomethane method (US 5,312,974), acetic acid method (US 6,207,025) and electrochemical method (EP 0,331,864) and others. These methods generally have problems such as complex process, long production pr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C303/24C07C309/04
Inventor 刘晓民刘占峰聂文娜娄强昆
Owner HEBEI YANUO CHEM IND
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