1. Institute of Petroleum and Chemical Engineering, College of Chemical and Pharmaceutical Engineering,Hebei University of Science and Technology, Shijiazhuang, 050018, China; 2. Bayin Guoleng Vocational College, Kuerle 841000, China
The deep eutectic solvent (DES) composed of choline chloride and urea was prepared on kilogram level. The molar ratio effect, temperature and reaction time on physi-chemical properties of the DES were investigated, respectively. Refractive index, conductivity, viscosity of samples and products were measured during the reaction process. A possible chemical structure of the DES was analyzed based on FT-IR infrared spectroscopy spectrum. Experimental results show that the deep eutectic solvent can not be formed for the ratio of choline chloride to urea of 1∶1 for the ratio of choline chloride to urea of 1∶1.5 and 1∶2, and not formed. In the case of the ration of 1∶2, the deep eutectic solvent can be formed at 70, 80 and 90 ℃, and not at 60 ℃. The required time of the reaction is shortened with the increasing temperature. When refractive index is 1.505, the DES exhibits constant properties, which suggested that a stable chemical structure is formed. In addition, water contents in feedstocks and product affect property of DES in some content. A difference of physichemical properties of DES in literatures was clarified. The study provides valuable data for commercial production of DES.