Conversion Of Sugar To Latic Acid Catalyzed By Polymer Ionic Liquid

A substitute for fossil fuels, green energy biomass, which has a very good application prospects. Lactic acid is an hydroxyl acid, which is widely used in the medicine, food, cosmetic and so on in chemical industry. In recent years, scholars is interested in the conversion of lactic acid by biomass. Choosing a suitable catalyst is very important in the alkaline water heat conditions preparation of lactic acid. Studies found that polymer ionic liquid as a catalyst show a better effect in the conversion sugars to lactic acid than the metal sulfide, metal choride, metal oxide and alkali.This paper synthesized a variety of imidazole aggregation of ionic liquid, imidazole group aggregation of ionic liquid [IMEP]C1 is composed of imidazole and epoxy chloropropane polymerization, other polymerized ionic liquids such as [IMEP] BF4、[IMEP]ClO4、[IMEP]phCOO、[IMEP]Ac is by ion exchange method. And the polymer ionic liquid characterized with thermogravimetric, nuclear magnetic, and infrared spectrum, the results showed that the polymer ionic liquids is very good. Polymer ionic liquid put up a good effect in the comversion sugar to lactic acid in the alkaline hydrothermal system.Polymer ionic liquidin the system of conversion fructose to lactic acid results show that:different polymer ionic liquid put up different effects, [IMEP]Cl is the best catalyst, under the condition of 100℃ 2 MPa N2, the concentration of fructose is 25 mmol/L, [IMEP]Cl and NaOH is 100 mmol/L and 50 mmol/L, the reaction time 30 min, the highest yield of lactic acid is 65%, [IMEP]Cl through five recycle, the yield of lactic acid still keep above 55%; In the system of conversion glucose to lactic acid, [IMEP]Cl also performed in addition to good catalytic effect, the single and orthogonal experiment optimization indicated that, the best react condition is 2 MPa N2, 100℃, the concentration of glucose is 25 mmol/L, NaOH 50 mmol/L, [IMEP]Cl 100 mmol/L, the reaction time is 45 min, and the highest yield of lactic acid is 60%.Ploymer ionic liquid [IMEP]Cl still put put good effect in the conversion dissccharide to lactic acid, the results show that 120℃,2 MPa N2, the concentrations of maltose is 25 mmol/L, NaOH 100 mmol/L, [IMEP]Cl 200 mmol/L, the reaction time is 90 min, the highest yield of lactic acid is 46.5%; 190℃,2 MPa N2, sucrose 25 mmol/L, NaOH 100 mmol/L, [IMEP]Cl 200 mmol/L, the reaction time is 13 h, the highest yield of lactic acid is 42.2%.Finally, there is a simply exploration in the reaction pathway and mechanism of conversion fructose to lactic acid using the [IMEP]Cl as catalyst. Fructose and glucose can be conversioned together, generated in the process of lactic acid hydrolysis fructose first generate glyceraldehyde and dihydroxyacetone, then dihydroxyacetone and glyceraldehyde heterogeneous generated after dehydration and enealcohol acetone aldehyde, finally acetone aldehyde by adding water and 1,2-hydrogen transfer to generate lactic acid.Using GC-MS by-products of the reaction system and intermediate products were tested. [IMEP]C1 play an important role in the the process of conversion dihydroxyacetone to glyceraldehydes.