Abstract: To prepare vitamin B₁₂ and to determine the optimal process parameters for the solvent-free crystallization technique, the purity and yield of the product were evaluated to optimize this technique using response surface methodology. The optimal process parameters were obtained as follows: evaporation temperature of 65 ℃, vacuum degree of 0.09 kPa, and concentration of 90 000 μg/mL prior to crystallization. It was shown that the solvent-free crystalization technique has high feasibility and effectiveness as the yield and quality of the final product were on par with that of solvent crystalization, if not better. While improving the safety of production, this technique cuts down pollution and eliminates certain procedures, thereby reducing the production cost and making it a good candidate for implementation in large-scale production.

Key words: vitamin B₁₂, solvent-free crystallization; response surface methodology