A kind of dissolution and crystallization method of pharmaceutical grade l-valine

Abstract

The invention relates to a medicinal L-valine dilution crystallization method.According to the technical scheme, the method comprises the steps that firstly, industrial L-valine and water are mixed, activated carbon is added for decoloration and impurity removal, then, nanofiltration is performed to obtain an L-valine crystallization mother solution, then, a seeding material control nucleation and dilution agent variable feeding combined strategy is adopted for controlling the particle size and crystal form of a crystal product in the L-valine dilution crystallization process, and the high-quality medicinal L-valine crystal is obtained.Compared with traditional evaporation, concentration, cooling and crystallization technologies, the method has the advantages of being short in production period, high in crystallization yield and good in product quality.

Description

technical field [0001] The invention belongs to the technical field of industrial crystallization, and in particular relates to a method for dissolution and crystallization of pharmaceutical grade L-valine. Background technique [0002] As one of the essential amino acids, L-valine plays an important role in the life metabolism of humans and animals. Its industrial application has gradually developed rapidly from traditional feed additives to high value-added industries such as food, medicine, and cosmetics. At present, although the industrial production scale of domestic L-valine ranks among the top in the world, there is a big gap in the overall quality of the product compared with foreign products, especially in terms of product crystal form, purity, particle size distribution and other indicators, resulting in many domestic L-valine L-valine does not meet the medicinal standards and can only be exported as low-end raw materials or as feed additives. The low added value o...

AI Technical Summary

Problems solved by technology

However, since the solubility of L-valine in water does not change much with temperature (about 7.5g / 100g water at 70°C; about 5.5g / 100g water at 10°C), when the cooling crystallization method is adopted, there is still a large amount of valine at the end of the crystallization. Solute dissolved in solvent, resulting in low yield of crystalline product

Moreover, whether it is evaporation concentration or cooling crystallization, crystal scaling is easy to form on the heat exchange surface, which significantly reduces the heat transfer efficiency, makes it difficult to control the evaporation rate or cooling rate, and prolongs the crystallization time, resulting in uneven particle size distribution of crystallized products and lower production efficiency. Low; and in the initial stage of the cooling crystallization process, the temperature difference between the industrial cooling water and the mother liquor is large, resulting in a high degree of supersaturation, and the crystallized product is easy to form spherical aggregate particles, and the resulting mother liquor occlusion and coalescence will significantly affect the product purity and particle size and color grade

In addition, regardless of evaporative crystallization or cooling crystallization, the solid-liquid suspension density in the industrial crystallization tank is high, the mixing in the crystallization tank is uneven, and the friction and collision between the crystals and between the crystal and the stirring paddle lead to serious crystal breakage during the crystallization process. It will also aggravate the uneven particle size distribution of crystallized products