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Method for preparing caffeine

A technology of caffeine and dimethyl, which is applied in the direction of organic chemistry, can solve the problems of cumbersome steps, low yield of caffeine products, and ineffective removal, so as to improve product yield and purity, reduce production cost, and shorten production cycle effect

Active Publication Date: 2012-02-08
JILIN SHULAN SYNTHETIC PHARMA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The three-step separation method is cumbersome and the yield of caffeine product is low
If the step of isolating and obtaining 1,3-dimethyl-4-amino-5-carboxamidoureazine is omitted, the preparation process can be saved and the production cost can be reduced, but 1,3-dimethyl-4-carbazine cannot be effectively removed. Impurities in amino-5-carboxamidoureazine (or theophylline sodium salt), the quality of caffeine products cannot meet the standard

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  • Method for preparing caffeine
  • Method for preparing caffeine
  • Method for preparing caffeine

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preparation example Construction

[0071] In the preparation method provided by the present invention, when adjusting the pH value, sulfuric acid is cheap and easy to purchase, and simultaneously sulfuric acid is a dibasic acid, which can provide more H + , the consumption is relatively low, which helps to reduce the cost of the product; at the same time, the properties of sulfuric acid are relatively stable, and it is a non-volatile acid. In the present invention, the oxidation reaction is carried out at a relatively high temperature. Yes, but hydrochloric acid is a volatile acid, which is not conducive to the working environment during operation. Hydrochloric acid is a monobasic acid, and the consumption is relatively high. Even if the price is the same as sulfuric acid, the consumption quantity will double, which will increase the cost of the product. Therefore, preferably, the acid described in step 2 or step 3 is sulfuric acid.

[0072] In some embodiments of the present invention, in the preparation metho...

Embodiment 1

[0082] The preparation of embodiment 1 caffeine

[0083] Prepare 1,3-dimethyl-4,5-diaminocarbazine with conventional dimethylurea method; specifically, take 178.5kg cyanoacetic acid, excess dimethylurea, and excess acetic anhydride to obtain dimethicone through condensation reaction Methyl cyanoacetyl urea: add sodium hydroxide to the dimethyl cyanoacetyl urea feed solution for ring closure reaction, then add sodium nitrite and sulfuric acid for nitrosation reaction, then add iron powder, sodium chloride and sulfuric acid for reduction reaction 282.97kg of 1,3-dimethyl-4,5-diaminocarbazine was obtained.

[0084]Use hot water to adjust the concentration of 1,3-dimethyl-4,5-diaminocarbazine to 12.3 (w / v), adjust the temperature to 90°C and add 110.97kg of formic acid for acylation reaction to obtain 1,3- Dimethyl-4-amino-5-formamidoureazine 329.55kg; Acylation reaction finishes insulation reaction 30min; Liquid is cooled to 85 ℃ and adds the liquid sodium hydroxide 182L of 40%...

Embodiment 2

[0087] The preparation of embodiment 2 caffeine

[0088] Prepare 1,3-dimethyl-4,5-diaminocarbazine with conventional dimethylurea method; specifically, take 178.5kg cyanoacetic acid, excess dimethylurea, and excess acetic anhydride to obtain dimethicone through condensation reaction Methyl cyanoacetyl urea: add sodium hydroxide to the dimethyl cyanoacetyl urea feed solution for ring closure reaction, then add sodium nitrite and sulfuric acid for nitrosation reaction, then add iron powder, sodium chloride and sulfuric acid for reduction reaction 281.31kg of 1,3-dimethyl-4,5-diaminocarbazine was obtained.

[0089] Adjust the temperature to 90°C and add 106.15kg of formic acid to carry out the acylation reaction to obtain 327.6kg of 1,3-dimethyl-4-amino-5-carboxamidoureazine; the end of the acylation reaction controls 1,3-dimethyl -The concentration of 4-amino-5-formamidoureazine is at 13.6% (w / v), and it is incubated for 45 minutes; Cool the feed liquid to 86°C and add 172L of...

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Abstract

The invention relates to the field of chemical synthesis, in particular to a method for preparing caffeine. The method comprises the following steps of: adding an oxidizing agent to remove reducing impurities after ring closure, and adding a reducing agent to remove oxidizing impurities in a refining process of crude caffeine. Therefore, the yield and the purity of the product are improved, the separation of 1, 3-dimethyl-4-amino-5-allophamic acid amide is dispensed with, the production period is shortened, and the production cost is reduced.

Description

technical field [0001] The invention relates to the field of chemical synthesis, in particular to a method for preparing caffeine. Background technique [0002] Caffeine, whose chemical name is 1,3,7-trimethylxanthine, is white or yellowish-green, mercerized needle-like crystals, sublimated and refined into hexagonal prism-shaped crystals, and its molecular formula is C 8 h 10 N 4 o 2 , the molecular weight is 194.19, and the structural formula is as follows: [0003] [0004] Caffeine has a strong excitatory effect on the central nervous system and a selective excitatory effect on the cerebral cortex. A small dose of caffeine can enhance the exciting process of the cerebral cortex, improve thinking activities, invigorate the spirit, eliminate drowsiness and fatigue, and make the work more agile and efficient. Large doses of caffeine can directly excite the medullary respiratory center and vasomotor center, making respiration quicker and deeper, and blood pressure el...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D473/12
Inventor 郭跃民尹焕新李立冬
Owner JILIN SHULAN SYNTHETIC PHARMA