异维生素C钠的转化新方法

New Conversion Technology of Sodium Isoascorbate

以异维生素C钠发酵液的前体物质2-酮基-D-葡萄糖酸(2KG)为主原料,甲醇为反应物,浓硫酸作催化剂,甲酯化反应4 h后,用碳酸氢钠作催化剂,经内酯化反应生成异维生素C钠(D-VCNa).考察了转化时间、转化温度及原料投料比对产品转化率和质量的影响.结果表明,选用碳酸氢钠作催化剂时,降低反应温度和适当延长反应时间有利于提高产品的转化率和质量.确定了较佳的工艺条件为:n(2KG)∶n(CH3OH)∶n(NaHCO3)=1∶18∶1.1,转化温度55℃,转化时间3 h.在该条件下,异维生素C钠的质量分数达95.5%以上.该法反应温和,转化温度较低,转化过程中料液破坏程度低,粗品质量好,可以进行一道精制得合格产品,收率得到较大提高,成本明显降低,已通过省级科技成果鉴定.

With 2-Keto-D-gluconic acid （2KG）, methanol as raw materials, 98% concentrated sulfuric acid as catalyst, methyl ester reacting 4 h and then with NaHCO3 for the catalyst by the lactonizate reaction of sodium isoascorbate, reaction time, the temperature and molar ratio of raw materials on product yield and quality are investigated tion temperature and appropriatly extending the reaction The results show that reducing the reactime will help to improve product quality and yield. A better process condition is determined as follows： n（2KG） ： n （CHaOH） ： n（NaHCO3）=1 ： 18 ： 1. 1, reaction temperature 55℃, reaction time 3 h. Under these conditions, the content of I^VCNa is above 95.5%. This method is under mild reaction conditions.Quality product can be carried out through a refining of good quality crude. The yield has been improved, and the cost is greatly redueed. This method has been identified through the provincial-level scientific and technological achievements.