Accurate heat capacity determination of urea phosphate using a power compensation microcalorimeter
To accurately determine the specific heat capacity,a power-compensated microcalorimeter was utilized to continually measure the modest energy changes that occurred throughout the perfectly regulated temperature rise and decrease process.The specific heat capacities of six substances(four solids and two liquids),including water,sapphire,and benzoic acid,determined by this method were found to be within 1.2% deviation of the literature values,indicating that the method has high measurement accuracy and is suitable for continuous measurement of various solids and liquids.Urea phosphate with high purity and crystallinity was obtained by complexation reaction and cooling crystallization using phosphoric acid and urea as raw materials,and was characterized by elemental composition analysis,XRD,infrared spectroscopy,and melting point test.Furthermore,the specific heat capacities of urea phosphate were determined in the temperature range of-20 to 100℃by this method.The obtained data were well correlated by a second-order polynomial and related thermodynamic functions were computed.This study provides crucial data for the application of urea phosphate in the field of food processing,as well as a new and efficient method for determining the specific heat capacity of various food additives.
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