| Myo-inositol belongs to the vitamin group.It can be widely used in food,medicine,feed,cosmetics and other industries.Almost all living organisms contain bound or free inositol.Compared with foreign myo-inositol products,the quality of domestic myo-inositol products has a certain gap.The main problems are small grain size,poor crystal morphology and color level.Based on this,the cooling crystallization process of myo-inositol was studied systematically in this paper.The crystallization thermodynamics and crystallization kinetics data of myo-inositol under different conditions were measured experimentally,and the crystallization process of myo-inositol was optimized according to the data.The solubility,density and the metastable zone width of myo-inositol(303.15k-333.15k)and ethanol mole fraction were measured in the range of 0 ~ 0.06.The solubility of myo-inositol was determined by static weighing method.It was found that the solubility of myo-inositol in water-ethanol mixture was a function of temperature,and the solubility increased with the increase of temperature.The solubility decreases with the increase of the mole fraction of ethanol in the solvent.The modified Apelblat empirical equation was used to correlate the solubility data.Density was measured by pycnometer method.It was found that the density of inositol increased with the increase of solution saturation temperature.However,when the molar fraction of antisolvent ethanol increased slightly,the density of inositol solution decreased significantly.The metastable zone width was measured by laser method.The effects of temperature,cooling rate and solvent composition on the metastable zone width were investigated.It is found that the metastable zone width of myo-inositol increases with the increase of cooling rate when the temperature is constant.At a certain cooling rate,the metastable zone width narrates with the increase of saturation temperature.When the temperature and cooling rate remained unchanged,the metastable zone width of myo-inositol decreased with the increase of the mole fraction of ethanol in the mixed solvent.The cooling crystallization kinetics of myo-inositol in pure water was studied by intermittent dynamic method.The effects of supersaturation,temperature and cooling rate on nucleation rate and growth rate were investigated.The growth rate and nucleation rate were obtained by using the method of moment transformation,and the nucleation kinetics and growth kinetics equation of myo-inositol were obtained by using the least square method and linear regression of Matlab software.The decolorization process and cooling crystallization process of myo-inositol were studied.In the decolorization process,the effects of the type of activated carbon,the amount of activated carbon,the decolorization temperature and the decolorization time on the decolorization effect were investigated.In the cooling crystallization process,the effects of crystallization temperature,stirring speed,cooling rate and other technological conditions on the crystal products were investigated,and the optimum decolorization and cooling crystallization technological conditions for producing myo-inositol were finally determined. |
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