Glucose Paired Electrolytic Synthesis Of Mannitol, Sorbitol And Sodium Gluconate

Mannitol, sorbitol and gluconate are widely used in many field such as medicine, foodstuff, chemical industry and so on. With the exploiting of mannitol' s use, the number of using mannitol is creasing, but mannitol is lack in China. Recently, mannitol is mostly extracted from kelp by the factories of beach cities, such as Qingdao, Dalian and so on. The production cost is high. With the prolution of sea becoming more and more seriously, the source of kelp has been becoming more and more little, so the price of kelp rises continuously. Output of mannitol is limited by the source of kelp. Because mannitol is very important in china and abroad, chemistists are devoting themselves to the study of chemical producing mannitol. It is well known that a mixture of sorbitol and mannitol in aqueous solution can be produced by catalytic hydrogenation at high press and high temperature, it cost lot. But electro organic synthesis mannitol can be done at normal press and temperature and don' t need special reagent. This method has potential applicaton. Using electrochemical method, we have simultaneously obtained mannitol, sorbitol and gluconate in a cell from raw glucose. The paper has not been reported, so the study is valuable. The major contents of the paper are described as followed.1. Cathode materials are studies. Usually, we select high hydrogen overpotential material as cathode to avoid giving off hydrogen. In this study, I selected not only high hydrogenoverpotential material, but also low hydrogen overpotential' s, such as Ni and RaneyNi. RaneyNi cathode is the best. In this experiment, low hydrogen overpotential RaneyNi in place of high hydrogen overpotential Pb, Zn.2. Catalytically epimerizing glucose in a nonalkaline aqueous solution, thereby obtaining a mixture of glucose and mannose in solution. Ammonium molybdate is used for the epimerization reaction, which is conducted under the condition of pH=3. 5 and temperature is 100癈. Mannose formation ratio is 33%.3. RaneyNi powder was put into the cell. It flow with the electrolyte. Electrosynthesis is done under normal press using self-made parallel plate cell that had been used in other reaction. Glucose convent ratio is improved significantly from 20% to 60%.4. The electrochemical reduction a mixture of glucose and mannose. The factors that effect reduction, such as current density, the initial concentration of glucose, pH, temperature and the passed charge. The optimum operating condition for the reduction are RaneyNi powder cathode, 0. Smol.L"' of sugars, pH=10, 60癈 solution temperature, an applied current dendity of 4A/dm2, passed charge of 1.2F/mol. Glucose reduction ration is improved furtherly to 70%. 30% of the totle of mannitol and sorbitol is mannitol, which is higher than before.5. The electrochemical oxidation of glucose to gluconic and reduction to mannitol and sorbitol is paired in an divided paralleplate cell. Select RaneyNi powder as a cathode and DSA as a anode. The reduction condition is just pair synthesis' s. The study will continue.Using electrochemical method, we have simultaneously obtained mannitol, sorbitol and gluconate in a cell from raw glucose. Now, nobody do this work. RaneyNi powder is put into electrolyte and flow with it. Catalytically epimerizing glucose to obtaining a mixture of glucose and mannose before synthesis to improved yield. All those haven' t been studied before.