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A method of preparing caffeine

A technology of caffeine and theophylline sodium salt is applied in the methylation of theophylline sodium salt to obtain caffeine. Uneven mixing and other problems, to achieve the effect of eliminating VOCs emissions, saving manpower, and eliminating batch differences

Active Publication Date: 2021-07-16
CSPC INNOVATION PHARMA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] There are many deficiencies in the original process: due to the large tank body, the methylation reaction tank is easy to cause local uneven mixing of materials, resulting in a large consumption of dimethyl sulfate
Dimethyl sulfate is a highly toxic organic compound, the original process can not effectively achieve human-machine separation

Method used

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  • A method of preparing caffeine

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Embodiment 1

[0025] Embodiment 1: prepare crude product caffeine with the inventive method

[0026] Preparation of tea sodium feed solution with a mass content of 15%. The sodium tea solution at a flow rate of 24 mL / min and the dimethyl sulfate at a flow rate of 1.6 ml / min were simultaneously fed into the continuous mixing reactor, and the molar ratio of dimethyl sulfate to theophylline sodium salt was controlled to be 1.1:1. Adjust the pH value to between 8 and 10 with 30% sodium hydroxide solution. The reaction temperature was controlled to be 50°C. The effluent enters the crystallization tank for cooling and crystallization. When the temperature dropped below 20°C, solid-liquid separation was carried out, followed by drying to obtain 127.4 g of crude caffeine. The yield of crude caffeine was 98.8%.

Embodiment 2

[0028] The tea sodium feed solution with a mass content of 13% was prepared. The tea sodium solution with a flow rate of 24mL / min and the dimethyl sulfate with a flow rate of 1.82ml / min were simultaneously fed into the continuous mixing reactor, and the molar ratio of dimethyl sulfate to theophylline sodium salt was controlled to be 1.2:1. Adjust the pH value to between 8 and 10 with 30% potassium hydroxide solution. The reaction temperature was controlled to be 50°C. The effluent enters the crystallization tank for cooling and crystallization. When the temperature dropped below 20°C, solid-liquid separation was carried out, followed by drying to obtain 126.9 g of crude caffeine. The yield of crude caffeine was 98.4%.

Embodiment 3

[0030] The tea sodium feed solution with a mass content of 12% was prepared. The sodium tea solution with a flow rate of 24mL / min and the dimethyl sulfate with a flow rate of 2.18ml / min were simultaneously fed into the continuous mixing reactor, and the molar ratio of dimethyl sulfate to theophylline sodium salt was controlled to be 1.3:1. Adjust the pH value to between 8 and 10 with 30% sodium hydroxide solution. The reaction temperature was controlled to be 45°C. The effluent enters the crystallization tank for cooling and crystallization. When the temperature dropped below 20°C, solid-liquid separation was carried out, followed by drying to obtain 127.01 g of crude caffeine. The yield of crude caffeine was 98.5%.

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Abstract

The invention discloses a method for preparing caffeine, which comprises the following steps: 1) configuring the theophylline sodium salt feed liquid, 2) synchronously injecting the theophylline sodium salt feed liquid and dimethyl sulfate into a continuous mixing reactor, heating conditions Adjust the pH to 8-10 with an alkaline solution to obtain a caffeine solution. 3) The caffeine solution obtained in step 2) enters a crystallization tank for cooling and crystallization, cools down to 20° C., separates solid and liquid, and dries to obtain caffeine. The method reduces the consumption of dimethyl sulfate, and realizes automatic and continuous production. It has the advantages of high efficiency, safety, environmental protection and higher yield.

Description

technical field [0001] The invention belongs to the field of organic compound synthesis, in particular to a method for preparing caffeine, in particular to a method for obtaining caffeine through methylation of theophylline sodium salt. Background technique [0002] Theophylline sodium salt (referred to as "tea sodium"), chemical name 1,3-dimethylxanthine sodium salt, is an important organic intermediate, widely used in medicine, food, chemical industry and other fields. At present, the synthesis of caffeine is generally obtained by the methylation reaction between theophylline sodium salt and methylating reagent dimethyl sulfate. Shan Bin (Shan Bin, Jiang Man, etc. Research on the consumption reduction process of dimethyl sulfate in the caffeine production process [J]. Fine Chemical Petroleum Progress, 2015,16(3):55-57) disclosed theophylline sodium salt The methylation yield was 95%. It uses theophylline sodium salt and dimethyl sulfate for batch reaction, and adds a pha...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D473/12
Inventor 韩峰周英壮郭少卿周云雪谢丽莎
Owner CSPC INNOVATION PHARMA