On The Development Of The Creativity Of Postgraduates

Ethyl maltol(2-ethyl-3-hydroxy-4H- pyranone-4) is worldwide-popular fragrance added additive, which is widely used in the fields of food, drug and cosmetic. Nowadays, most of domestic companies use a chemical process which uses furfural as its raw materials. Furfural reacts with grignard reagent to form ethyl furfuralcohol and finally ethyl matol through a series of complex chemical processes. However, this process discharges a great deal of diluted scrap hydrochloride acid which contains much sodium chloride, as well as contaminated magnesic slurry. In this paper, a green circular technology for ethyl maltol is designed. With this green circular technology, the process uses non-contaminative raw materials and discharges no pollution to environment, as well as using no contaminative energy. High concentration of purified hydrochloric acid is successfully recycled by intermittent distillation subsequent side distillation on the basis of its imperfection. The conversion from intermittent distillation to side distillation is realized when the bottom temperature reaches to 113℃. Peculiar tri-phase distillation for the recovery of salty scarp acid is mentioned here. Exploratory experiments indicate that purified hydrochloric acid can be concentrated to 12% from 2.5% steadily by an especial method of decompressed side distillation associated with salt-removal. The optimum conditions of distillation are searched, such as bottom temperature, bottom pressure, concentration, filling velocity and reflux ratio. In a low pressure of 40kPa, the bottom temperature decreases to below 80℃, the optimum filling velocity is 0.04mL/s. Its optimum collecting ratio and reflux ratio of the top and the side are 80%, 2.2, 20%, zero respectively. In these conditions, continuous recovery of scrap acid is realized through the salt-removal in a proper temperature range of 100-90℃. What's more, the chemical process of converting the contaminated magnesic slurry to excellent grade of industrial magnesium hydroxide has been studied. The optimum reacting time in producing magnesium hydroxide is 60 minutes, the optimum qualitative ratio of sodium hydroxide and magnesium in the magnesic slurry is 2.4:1, the optimum concentration of the sodium hydroxide is 3mol/L, the best crystal seed is the reaction solution used for three times. This green circular technology eliminates the contamination to the environment as well as makes full use of the raw and processed materials.