Method for preparing methyl o-anisate

A technology of methyl o-methoxybenzoate and dimethyl sulfate, which is applied in the field of organic compound synthesis, can solve the problems of multiple waste liquids and residues, low conversion rate of methylation reaction, poor quality and the like, and achieves good economic benefits and social benefits, shorten the response cycle, and improve the effect of practicality

Inactive Publication Date: 2012-02-15
苏州诚和医药化学有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantages of this process include: 1) Because dimethyl sulfate is easily decomposed under alkaline conditions, the amount of dimethyl sulfate used in the process is relatively large; 2) The conversion rate of the methylation reaction is low, and the intermediate o-methoxy The separation of benzoic acid is difficult, and the purity is low, the general content is about 90%; 3) A large amount of acidic saline wastewater is generated during the acid separation of the product; 4) Concentrated sulfuric acid is used as a catalyst for the esterification reaction, and a large amount of acidic wastewater is also generated in the post-treatment; 5) Due to the low content of the intermediate o-methoxybenzoic acid, the quality of the final product methyl o-methoxybenzoate is poor, the product content is about 98%, and more waste liquid and residue are produced after distillation

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0013] To prepare methyl o-methoxybenzoate, the feeding ratio (molar ratio): salicylic acid: potassium carbonate: dimethyl sulfate=1:1.8:1.3. Feeding amount: salicylic acid 276kg, potassium carbonate 497kg, dimethyl sulfate 328kg, solvent acetone 828kg, rinse acetone 276kg.

[0014] Put 828kg of acetone, 497kg of potassium carbonate, and 276kg of salicylic acid into a 2,000-liter reactor in sequence, start stirring, and under cooling conditions, control the temperature below 35°C and slowly add 328kg of dimethyl sulfate dropwise for 2 to 2.5 hours. After the dropwise addition of dimethyl sulfate is completed, slowly raise the temperature to 45~50°C, and keep it at this temperature for 8 hours. After the heat preservation is over, cool the material to below 30°C, centrifugally filter, collect the filtrate to the concentration kettle, rinse the filter residue with 276kg of acetone and combine The filtrate was distilled at atmospheric pressure. After the acetone was evaporated, t...

Embodiment 2

[0017] To prepare methyl o-methoxybenzoate, the feeding ratio (molar ratio): salicylic acid: potassium carbonate: dimethyl sulfate = 1:2.0:1.5. Feeding amount: salicylic acid 276kg, potassium carbonate 552kg, dimethyl sulfate 378kg, solvent acetone 828kg, rinse acetone 276kg.

[0018] Put 828kg of acetone, 552kg of potassium carbonate, and 276kg of salicylic acid into a 2000L reactor in turn, start stirring, and slowly add 378kg of dimethyl sulfate dropwise under cooling conditions to control the temperature below 35°C. The dropping time is 2~2.5h. After the addition of methyl ester is completed, slowly raise the temperature to 45-50°C and keep it warm for 10 hours. After the heat preservation is over, cool the material to below 30°C and filter it centrifugally. After the acetone is completely evaporated, the material is transferred to the distillation kettle, the vacuum unit is started, and the temperature is raised to control the vacuum degree of 15mmHg to collect the fracti...

Embodiment 3

[0021] To prepare methyl o-methoxybenzoate, the feeding ratio (molar ratio): salicylic acid: potassium carbonate: dimethyl sulfate=1:1.5:1.4. Feeding amount: salicylic acid 276kg, potassium carbonate 414kg, dimethyl sulfate 353kg, solvent acetone 828kg, rinse acetone 552kg.

[0022] Put 828kg of acetone, 414Kg of potassium carbonate, and 276kg of salicylic acid into a 2000L reaction kettle in sequence, start stirring, and under cooling conditions, control the temperature below 35°C and slowly add 353 kg of dimethyl sulfate dropwise for 2~2.5h. After the dropwise addition of dimethyl sulfate is completed, slowly raise the temperature to 45~50°C, and keep it at this temperature for 9 hours. After the heat preservation is over, cool the material to below 30°C, centrifugally filter, collect the filtrate to the concentration tank, rinse the filter residue with 552kg of acetone and combine The filtrate was distilled at atmospheric pressure. After the acetone was evaporated, the mate...

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Abstract

The invention discloses a method for preparing methyl o-anisate. The method comprises the following steps: based on salicylic acid as a starting raw material, acetone as a solvent, anhydrous potassium carbonate as a catalyst and dimethyl sulfate as a methylation reagent, stirring and reacting for 5-10 hours at the controlled temperature of 45-50 DEG C; after reaction is finished, cooling, filtering and recovering potassium salt; and recovering acetone by distilling filtrate under room pressure, and distilling under reduced pressure to obtain the product methyl o-anisate. The method is a one-step method for synthesizing methyl o-anisate, thus reaction period is shortened, and energy consumption is greatly reduced; the product potassium salt (potassium sulfate) can be sold, and waste slag is not generated; potassium carbonate is adopted for catalytic reaction, potassium carbonate has high activity and conversion rate reaching more than 99%, and waste liquid and residue are hardly generated; recovered acetone can serve as the solvent to be directly used for reaction, thus cost is low; and prepared methyl o-anisate has high content being more than or equal to 99.5% (GC (gas chromatograph)), good quality, low salicylic acid content being less than or equal to 0.1% and low moisture content being less than or equal to 0.3%. The method disclosed by the invention has the advantages of good practicability, and better economic benefits and social benefits.

Description

technical field [0001] The invention belongs to the technical field of organic compound synthesis, in particular to a method for preparing methyl o-methoxybenzoate. Background technique [0002] Methyl o-methoxybenzoate is currently used in the industry as follows: salicylic acid is methylated with sulfuric acid diformic acid and water is used as a solvent under alkaline conditions, and then acid is separated to obtain o-methoxybenzoic acid. After drying, it is esterified with methanol by concentrated sulfuric acid, recovers methanol, washes with water, and separates to obtain the crude product of methyl o-methoxybenzoate, which is then subjected to high vacuum distillation to obtain o-methoxybenzoate Methyl benzoate. The disadvantages of this process include: 1) Because dimethyl sulfate is easily decomposed under alkaline conditions, the amount of dimethyl sulfate used in the process is relatively large; 2) The conversion rate of the methylation reaction is low, and the in...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C69/92C07C67/11C07C67/31
Inventor 王利明夏秋景陈浩
Owner 苏州诚和医药化学有限公司
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