The solubility of eszopiclone in four binary solvents (ethanol + water, tetrahydrofuran + water, acetonitrile + water, acetone + water) at the temperature range of T = (288.15−328.15) K was determined with the gravimetric method. The experimental results showed that the solubility of eszopiclone increased as temperature rose. It was observed that the solubility varied in the binary solvent systems with the change in the fraction of water. The dissolution ability of the aqueous solvent mixtures was obviously improved with the added water. The characterization of the solid samples with X-ray powder diffraction showed that the crystal form of eszopiclone remained stable in this experiment. The increase of solubility in a binary solvent system may be related to the effect of a hydrogen bond. The experimental solubility data were correlated with the solvent composition and temperature using the CNIBS/R-K model and the Jouyban−Acree model. It was found that the calculated solubility was consistent with the experimental data. These results could give guidance to practical industrial processes such as the design of a crystallization process.
Ticagrelor (TCG) is a P2Y12 platelet inhibitor and has several crystal forms including Form II and Form V. In this work, it has been confirmed that Form II TCG would gradually transform to Form V in selected solvents. According to the crystal form stability, a dynamic method was adopted to measure the solubility of Form II TCG in six pure solvents (n-propanol, isopropanol, n-butanol, 2-butanol, ethyl acetate, and isopropyl acetate). The solubility of Form V TCG in 12 pure solvents (methanol, ethanol, n-propanol, isopropanol, n-butanol, 2-butanol, methyl acetate, ethyl acetate, isopropyl acetate, acetone, 2-butanone, and cyclohexanone) was measured by a static method. The solubility measurement temperature range was from 273.15 to 313.15 K. The experimental solubility data were correlated by the modified Apelblat model and the λh model. It was shown that the calculated solubility was consistent with the experimental data.
The one-step hydrotreatment of rubber seed oil to produce hydrocarbon fuels has been carried out via supported Pd-catalyst, and analyzed emphatically some elements affected catalytic cracking process, for example, temperature, hydrogen partial pressure and dosage of catalyst, etc. Through experimental research, the author found out the appropriate catalytic cracking conditions as follows: 310°C of reaction temperature, 2 MPa of hydrogen partial pressure, 15 of the ratio of oil to catalyst (m(oil)/m(catalyst)), 100 r/min of stirring speed. Under these conditions, effective component of hydrocarbon fuels in the converted oil accounts for 99.49%, and the proportion of C 8 -C 16 can reach as high as 79.61%. The converted oil was similar to petroleum-based oil in chemical composition, and can be used for future the aviation biofuels development as the source of raw material because it contains a large amount of hydrocarbon in the range of C 8 -C 16 . et al. Converting rubber seed oil into hydrocarbon fuels via supported Pd-catalyst. Int J Agric & Biol Eng, 2017; 10(6): 201-209.
As a classic drug with several hydrate forms, Calcium Dobesilate is widely used in the treatment of diabetic retinopathy and chronic venous insufficiency, and Monohydrate is the medicinal form. The key impurity, hydroquinone, is an important synthetic raw material of Calcium Dobesilate, but has a potential genotoxicity, so the content of hydroquinone in the final product should be lower. In this paper, based on characterization results of different hydrates, the Dihydrate is found as the beneficial form for purification, thus a novel crystallization process for purification has been carried out. The Dihydrate is obtained by a recrystallization and then transformed into the Monohydrate. From the results of solid‐state characterization and process analysis of phase transformation, the transformation relationship between the two hydrates is determined, and it is found out that the transformation from Dihydrate to Monohydrate could only happen via solution‐mediated transformation in Ethanol or Isopropanol. The impurity content of the Monohydrate product prepared by the new crystallization process is far below the current standard in the Pharmacopoeia.
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