Preparation method of DL-panthenol
A technology of panthenol and crystal seed is applied in the field of preparation of DL-panthenol, which can solve the problem of high yield of DL-panthenol, and achieve the effects of being beneficial to industrial production, reducing precipitation and reducing energy consumption.
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Embodiment 1
[0029] The present embodiment provides a kind of preparation method of DL-panthenol, comprises the following steps:
[0030] (1) Add ethyl acetate 820kg, DL-pantolactone 520kg (quality after converted purity) and 3-aminopropanol 300kg (quality after converted purity) successively in a dry and clean 5000L reactor, and heat up to 45°C, stirred and reacted for 6 hours to obtain DL-panthenol solution;
[0031] (2) Cool down the DL-panthenol solution to 20°C, add 100g of DL-panthenol, then continue to cool down to -5°C, after crystals appear, keep warm for 6h under stirring conditions for crystallization, and centrifuge to obtain DL-panthenol The wet product obtained 791kg of DL-panthenol solid after vacuum drying.
[0032] After testing, the specific rotation of the DL-panthenol product is 0, the residual content of 3-aminopropanol is ≤0.1%, the melting point is 65°C, the weight loss on drying is ≤0.5%, and the heavy metal content is ≤10ppm. DL- The panthenol content is 99.5%, a...
Embodiment 2
[0034] The present embodiment provides a kind of preparation method of DL-panthenol, comprises the following steps:
[0035] (1) Add ethyl acetate 845kg, DL-pantolactone 545kg (quality after converted purity) and 3-aminopropanol 300kg (quality after converted purity) successively in a dry and clean 5000L reactor, and heat up to 50°C, stirred and reacted for 4 hours to obtain DL-panthenol solution;
[0036] (2) Cool down the DL-panthenol solution to 10°C, add 100g of DL-panthenol, then continue to cool down to 5°C, after crystals appear, keep warm for 8h under stirring conditions for crystallization, and centrifuge to obtain DL-panthenol wet product, and obtained DL-panthenol solid 791kg after vacuum drying.
[0037] After testing, the specific rotation of the DL-panthenol product is 0, the residual content of 3-aminopropanol is ≤0.1%, the melting point is 65°C, the weight loss on drying is ≤0.5%, and the heavy metal content is ≤10ppm. DL- The panthenol content is 99.3%, and ...
Embodiment 3
[0039] The present embodiment provides a kind of preparation method of DL-panthenol, comprises the following steps:
[0040] (1) Add ethyl acetate 835.6kg, DL-pantolactone 535.6kg (mass after converted purity) and 3-aminopropanol 300kg (mass after converted purity) successively in a dry and clean 5000L reactor, The temperature was raised to 40°C, and the reaction was stirred for 5 hours to obtain a DL-panthenol solution;
[0041] (2) Cool down the DL-panthenol solution to 15°C, add 100g of DL-panthenol, and then continue to cool down to 0°C. After crystals appear, keep it warm for 7h under stirring conditions for crystallization, and centrifuge to obtain DL-panthenol wet product, and obtained DL-panthenol solid 796kg after vacuum drying.
[0042] After testing, the specific rotation of the DL-panthenol product is 0, the residual content of 3-aminopropanol is ≤0.1%, the melting point is 65°C, the weight loss on drying is ≤0.5%, and the heavy metal content is ≤10ppm. DL- The p...
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