Process Improvement On The Synthesis Of Menadione Sodium Bisulfite And Thermodynamics Of Relative Solution

Menadione sodium bisulfite (MSB) is an important drug, feed additive with wide uses and optimum application prospects. With the development of medicine, feed industry, the need for menadione sodium bisulfite was yearly increased both in China and abroad, however the supply is insufficient. Traditional synthesis methods of MSB generally had defects, such as low yield, low product purity, high cost, serious pollution and complex techniques, so new technology on the synthesis of MSB becomes the research hotspot in the world. Based on the traditional process on the synthesis of MSB, the synthesis method of MSB has been improved and the fluid phase equilibria, volumetric and viscosity properties were researched in this paper. These have a great science and applied significance.In the synthesis of MSB, the traditional raw material 2-methyl- 1, 4-naphthoquinone (2-MNQ) contains 6-Methyl- 1, 4-naphthoquinone (6-MNQ), resulting in lower product. To improve product quality, 6-MNQ was separated and removed from the mixture of 2-MNQ, then 2-MNQ and sodium bisulfite react to obtain MSB in o-xylene solution. The optimum process conditions for separation were found that mole ratio of 6-MNQ to sodium bisulfite 1:1.15, reaction temperature 20℃and reaction time 10min; The optimum process conditions for sysnthesis were mole ratio of 2-MNQ to sodium bisulfite 1:1.45, reaction temperature 40℃and reaction time 4h. The results showed that after process improvement, yield of MSB was over 81%, mass fraction of MSB was more than 98%, and the improved synthetic procedure is practical and fit to popularize in industry, and the production cost is reduced.The research on phase state, density and volumetric properties, viscosity and transport properties for solution is very important for the chemical engineering designs, reaction process, solution theory and molecular thermodynamics, and there are quite a few researches on solubility of 2-MNQ or MSB in organic solvents, density and volumetric properties, viscosity and transport properties for containing 2-MNQ or MSB solution. So in this study, using a laser monitoring observation technique, the solubilities of 2-MNQ in mixed solvent of water + alcohols (such as methanol, ethanol, 1-propanol etc.), 2-MNQ in benzene, toluene, ethylbenzene, o-xylene, m-xylene, and p-xylene, and MSB in mixed solvent of water + alcohols, have been determined experimentally. The experimental data are correlated with the modified Apelblat; the constants of equations were obtained. The relative deviations between the experimental value and calculated value were less than 2.0%. According to scatchard-Hildebrand theory, compatible with similar principle and experimental results, the results of experiment were discussed.The densities and viscosities of 2-MNQ + benzene, toluene, ethylbenzene, o-xylene, m-xylene, and p-xylene, respectively, MSB + 45wt% ethanol + water, MSB + 60wt% ethanol + water and MSB + 75wt% ethanol + water mixtures have been measured from 303.15 K to 333.15 K. The experimental data are correlated with the VTF equation and the constants of equation were obtained. The standard deviations between the experimental value and calculated value were less than 1.0%. From measurements of densities, the apparent molar volumes and the standard partial molar volumes were calculated. The variation of volumetric properties was discussed based on molecular interactions.Through the study of solubility, density, volumetric properties, viscosity and appropriate model, this thesis not only enriches the basic research of chemical engineering and molecular thermodynamic, but also provides basic data and information for industrial production and farther research to the direct sulphonate-synthesis technology of MSB using raw material 2-MNQ.