Effect Of Solvent On The Dissolution Of Wool Keratin By Ionic Liquid

Keratin from wool is widely used in the environment and resource utilization. It is very important to increase the rate of wool keratin and shorten the time of reaction. N₂ should be considered during the process of regeneration keratin from wool in ionic liquids. Cosolvent was added into [BMIM][H₂PO₄], [BMIM][HSO₄], [BMIM][DBP] and [BMIM][DMP] to improve the extraction process. The keratin dissolved in ILs/urea and regenerated from ethanol was in better mechanical performances and would beneficial for applications in textiles, cosmetics, pharmaceuticals and food. In addition, the colsolvent exhibited as a highly effective, eco-friendly and recyclable material in regeneration of keratin from wool. Thus the process could be beneficial to address industrial requirements.（1） The ionic liquids [BMIM][H₂PO₄], [BMIM][HSO₄], [BMIM][DBP] and [BMIM][DMP] were designed and synthesized and their influence law to dissolve wool keratin were systematic studied. The anion and cation of ionic liquids have great impacts on the dissolution keratin and phosphate ester was better than acidic ionic. The polarity of the anion pecking order is DMP- >DBP- >HSO₄- >H₂PO₄-. In the phosphate ester case, this high solubility is presumably related to the ability of the ionic liquids phosphate ester ion to disrupt hydrogen bond and disulfide bond in the keratin material. The optimum extraction conditions for keratin were: 120°C, N₂, [BMIM][DMP] as solvent. The dissolution time under the optimum condition is 10.5h.（2） The synergistic effect of cosolvents and ionic liquids were studied in wool keratin dissolved in ionic liquids. In this study we found that it took the shortest time to dissolve the same wool in ionic liquids when the urea as cosolvent whereas the longest time was required to caprolactam. Cosolvents can unfold the disulfide bonds and hydrogen bonds to accelerate the dissolution of keratin. Urea probably was easier to form new hydrogen bonds and disulfide bonds to open original hydrogen bonds and disulfide bonds in wool. Therefore, urea should be selected to the best cosolvent and 5.0 wt.% wool fibers were dissolved under nitrogen within 4.5 h at the temperature of 120°C and urea/[BMIM]DMP mass ratio of 2.0%.（3） The effect of coagulation bath on the extraction of keratin from wool was studied. The keratin solution was added with ethanol, acetone, excess deionized water, methanol, acetic acid at room temperature to precipitate keratin. Keratin could be regenerated according to the solubility of ionic liquids and keratin in coagulation bath. The results show that methanol could improve the efficiency of keratin regeneration and reproducibility. Its structure is loose and it will be useful in industrial production and life. The method of recycling ionic liquid and precipitating water-soluble protein was studied. It is found that heating is a good way to achieve the precipitation of water-soluble protein and the recycling of ionic liquid. We also investigated the influence of the heating temperature on the process. The results showed that 85?C is the optimum temperature for the precipitation of water-soluble protein.