ABSTRACT
Objective To explore the feasibility using aluminum tripolyphosphate as the synthesis of aspirin model instead of sulfuric acid catalyst. Methods The thermodynamic functions of the reaction system of salicylic acid and acetic anhydride were calculated according to the Benson group contribution method and Joback group contribution method.The enthalpy change,entropy and Gibbs free energy along with the change of temperature as well as the influence of the molar rate of reactants on the equilibrium conversation rate were also studied.Results In the temperature range of 298.15 K to 358.15 K,the reaction enthalpy was less than zero,and was exothermic reaction,and increase of temperature was not conducive to the reaction.The improvement of mole ratio of salicylic acid and acetic anhydride was helpful to improve the equilibrium conversation rate.The theoretical conversion rate could reach 99.58% when the mole ratio of salicylic acid and acetic anhydride was 3.Conclusion From the viewpoint of thermodynamics, the reaction is practical and feasible.
ABSTRACT
Objective To study the structural and anticorrosive property of microcrystalline α-Zn3 (PO4)2 ·4H2O. Methods Zinc phosphate was prepared from zinc acetate and orthophosphate acid in aqueous solution.Structural characteristics of products were investigated by XRD, RAMAN, FTIR, TG-DTA, SEM, surface area,particle size distribution, and density measurements. Results The title compound, a highly crystalline, micronized (A), c0 =5. 0304(A), V=975.86 (A)3. Its specific area is 0. 701 m2/g, density 3. 1612 g/m3 , and average size 4.75μm . Conclusion Comparing with commercial Zinc phosphate, the synthesized iamellar microcrystalline zinc phosphate had excellent anticorrosive property and dispersibility.
ABSTRACT
Objective To establish a thin layer Chromatograph-Fluores cent method for the determination of karanjin in Radix of Fofdia caulifora. Methods Anhydrous-EtOH is solution, thin-sheet is silica gel, expanding solution is Benzene-EtoAc (8.5∶1.5), with excitation wavelength at 355 nm and emission wavelength at 428 nm. Results The average recovery of karanjin was 99.14% and RSD was 1.94% (n =5). There is a good linear relationship within the range of 0.138～0.69 ?g of karanjin. Conclusion The method is convenient, sensitive, accurate and reproducible, and can be used the quality control of the Radix of Fofdia caulifora.