CN-121990955-A - Preparation method of dark isopropyl ethyl thiamine ester

CN121990955ACN 121990955 ACN121990955 ACN 121990955ACN-121990955-A

Abstract

The invention discloses a preparation method of dark isopropyl ethyl thiamine, which comprises the steps of taking 200g of isopropyl ethyl thiamine base material, adding 5g of 8% hydrogen peroxide (effective H2O2 accounts for 0.2%) under the stirring condition of 35 ℃ and 250rpm, adding 0.3-3.4 g of 70% monoethylamine after stirring for 10 minutes, and reacting at constant temperature for 30 minutes to obtain dark isopropyl ethyl thiamine products. According to the invention, through accurately controlling the proportion and the 35 ℃ reaction condition, the continuous controllable change of the color of the thiamine ester from light reddish yellow to dark reddish brown is realized, the main peak deviation of the product chromatogram is less than or equal to 0.5%, the product is free from layering and precipitation after 8 hours of light shading and standing, the loss of main components is extremely low, and the process stability is strong, so that the method is suitable for industrial production.

Inventors

LI WENQIANG

Assignees

李文强

Dates

Publication Date: 20260508
Application Date: 20260201

Claims (3)

1. The preparation method of the dark isopropyl ethyl thiamine ester is characterized by comprising the following steps of: 200g of isopropyl ethyl thiamine base material is taken, 5g of 8% hydrogen peroxide (the effective H 2 O 2 relative to the base material accounts for 0.2%) is added under the stirring condition of 25-30 ℃ and 250rpm, after stirring for 10 minutes, 0.3-3.4 g of 70% monoethylamine is added, and the constant temperature reaction is continued for 30 minutes, so that a dark-color isopropyl ethyl thiamine product is obtained; the chromatographic main peak deviation of the product is less than or equal to 0.5 percent, and the product is free from layering and precipitation after being placed in a dark place for 8 hours.
2. The preparation method according to claim 1, wherein the dosage of 70% of monoethylamine is 0.3g, 1.0g, 2.3g or 3.4g, and the corresponding product colors are light reddish yellow, red yellow, reddish brown and dark reddish tan respectively.
3. The dark isopropyl ethyl thiamine ester prepared by the method of claim 1 or 2, wherein the product is light reddish yellow to dark reddish brown, the deviation of the main chromatographic peak is less than or equal to 0.5%, and the dark isopropyl ethyl thiamine ester is free from layering and precipitation after 8 hours of light shading and standing.

Description

Preparation method of dark isopropyl ethyl thiamine ester Technical Field The invention belongs to the technical field of preparation of thiamine ester compounds, and particularly relates to a controllable preparation method of dark isopropyl ethyl thiamine ester. Background Isopropyl ethyl thiamine is an important industrial raw material, and the darkened product has higher practical value in specific application scenes. In the prior art, the deep color process of thiamine ester has the problems of uncontrollable color, large loss of main components (the main peak deviation of the chromatogram is usually more than 5 percent), poor process stability and the like, and can not meet the requirements of accurate control of the color of the product and stable main content in industrial production. Therefore, developing a preparation method of dark isopropyl ethyl thiamine with controllable color, small loss of main components and stable process becomes a technical problem to be solved in the field. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a preparation method of dark isopropyl ethyl thiamine ester, continuous controllable dark color of the thiamine ester is realized by precisely controlling the proportion of hydrogen peroxide and monoethylamine and the constant-temperature reaction condition of 35 ℃, the loss of main components is extremely low (the deviation of the main chromatographic peak is less than or equal to 0.5 percent), and the process stability is strong. The technical scheme of the invention is as follows: a method for preparing dark isopropyl ethyl thiamine ester, which comprises the following steps: 200g of isopropyl ethyl thiamine base material is taken, 5g of 8% hydrogen peroxide (the effective H 2O2 relative to the base material accounts for 0.2%) is added under the stirring condition of 35 ℃ and 250rpm, 0.3-3.4 g of 70% monoethylamine is added after stirring for 10 minutes, and the constant temperature reaction is continued for 30 minutes, so that a dark-color isopropyl ethyl thiamine product is obtained; the chromatographic main peak deviation of the product is less than or equal to 0.5 percent, and the product is free from layering and precipitation after being placed in a dark place for 8 hours. Further, the feeding amount of 70% of monoethylamine is 0.3g, 1.0g, 2.3g or 3.4g, and the corresponding product colors are light reddish yellow, red yellow, reddish brown and dark reddish brown respectively, so that continuous controllable change of the colors is realized. The invention has the beneficial effects that: The color is controllable, namely, continuous color change from light reddish yellow to dark reddish brown can be realized by adjusting the feeding amount of 70 percent of monoethylamine, and the requirements of different application scenes are met; The main content is stable, the chromatographic main peak deviation of the product is less than or equal to 0.5 percent, which is far superior to the prior art (usually more than 5 percent), the loss of main components is extremely low, and the process stability is extremely strong; the method has the advantages of simple process, mild reaction condition (35 ℃), simple and convenient operation, no need of complex equipment and suitability for industrial production. Detailed Description The present invention will be described in further detail with reference to the following examples, but the scope of the present invention is not limited to the following examples. Example 1 (lower dose) 200G of isopropyl ethyl thiamine base material is taken and placed in a constant temperature water bath at 35 ℃, magnetic stirring is started, the rotating speed is regulated to 250rpm, 5g of 8% hydrogen peroxide is added, after stirring for 10 minutes, 0.3g of 70% monoethylamine is added, constant temperature reaction is continued for 30 minutes, after the reaction is finished, a light red and yellow dark isopropyl thiamine product is obtained, the chromatographic main peak deviation of the product is detected to be less than or equal to 0.5%, and the product is kept stand in a dark place for 8 hours without layering and precipitation. Example 2 (intermediate dose) 200G of isopropyl ethyl thiamine base material is taken and placed in a constant temperature water bath at 35 ℃, magnetic stirring is started, the rotating speed is regulated to 250rpm, 5g of 8% hydrogen peroxide is added, after stirring for 10 minutes, 1.0g of 70% monoethylamine is added, constant temperature reaction is continued for 30 minutes, after the reaction is finished, a red-yellow dark isopropyl ethyl thiamine product is obtained, the chromatographic main peak deviation of the product is detected to be less than or equal to 0.5%, and the product is kept stand in a dark place for 8 hours without layering and precipitation. Example 3 (core dose) 200G of isopropyl ethyl thiamine base material is taken and placed in a constant temperature water