Gastrodin Intermediate 4 - Formylphenyl Tetraacetyl Glucopyranoside Glycoside Synthesis Research

At present, due to access to resources from the plant gastrodia gastrodin constraints. In recent years, prepared using synthetic gastrodin increasing the size and output. However, synthetic gastrodin process, the need to go through the first intermediate synthesis of bromo-acetyl glucose and 4-formyl-phenyl-2,3,4,6-4-O-acetyl-p-D-glucopyranoside, etc. processes. In these processes, most use a larger toxic red phosphorus and bromine, and excess of acetic anhydride, the remaining of the phosphorus and bromine in acetic acid treatment of low concentration is difficult to waste on the environment built into a relatively large contamination and hazard. Similarly, intermediate in the synthesis gastrodin 4-formyl-phenyl-2,3,4,6-4-O-acetyl-β-D-glucopyranoside in the process.Typically use more sugar and p-bromo-acetyl-formaldehyde reaction, and used acetone, KI, sodium hydroxide and other reagents, due to a lower conversion rate of the process, the yield was not high (usually 20～30%), and the complex process, is not conducive to reducing pollutant emissions, reduce energy consumption, cleaner production can not meet China's current requirements.In this paper, gastrodin synthetic intermediates for the existence of the above problems, from the angle of cleaner production of synthetic intermediates gastrodin bromoacetylic grapes and production processes used in the part of the raw materials and auxiliary materials, substances with low toxicity replacement, and to optimize the production process conditions for the purpose of reducing the pollution produced, while by-products and waste generated by resource utilization method of research.Bromoacetylic grapes in the synthesis process, using phosphorus tribromide red phosphorus and bromine substitution to reduce the toxicity of raw materials and environmental hazard.Experimental results show that the new synthetic process bromoacetylic glucose yield up to 82.4%, than the traditional synthesis methods yield an increase of about 10% to 15%, which to some extent, improved the conversion rate of raw materials, reducing the the amount of pollutants generated for the waste-processing reduces the cost of the synthetic process of clean bromoacetylic grape production levels may be raised.The gastrodin intermediate 4-formyl-phenyl-2,3,4,6-4-O-acetyl-β-D-glucopyranoside in the synthesis process, using phase transfer catalysis replace the existing KI catalytic is a method to improve the yield of the final product an effective manner. This paper studies several phase transfer catalyst performance, the use of benzyl triethyl ammonium chloride (BTEAC) can significantly improve the yield of this gastrodin intermediates, up to 47.2%, compared with the traditional process to improve the yield of about 17%,saving of raw materials, reducing the amount of pollutants generated. It also studied the effects of solvent system on the yield and select the best solvent ratio, reducing the consumption of acetone solvent, reducing the cost of dealing with the aftermath, but also achieved the purpose of energy saving and improve the level of cleaner production, but also produced a certain economic benefits.In the process against the inevitable waste generated by a low concentration of acetic acid, the present study was designed catalytic distillation column, using catalytic distillation approach, efficient, energy-saving waste acetic acid into the ethyl formate products in order to utilization of waste. The process of methanol feed location, alkyd feed molar ratio, catalyst concentration, reflux ratio, residence time, factors such as low concentration of waste to deal with the impact of acetic acid carried out a detailed study to optimize the treatment process, so that the conversion rate of acetic acid waste up to 98.65%, the purity of products obtained from methyl acetate up to 96.23%, the utilization of methanol up to 92.95%, achieved waste into high value-added acetate, ethyl formate, acetic acid, the full realization of the waste resource utilization, also made the whole process of clean production level has been improved.