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Thermochemical Properties and Decomposition Kinetics of Ammonium Magnesium Phosphate Monohydrate
Author(s) -
Wu Jian,
Yuan AiQun,
Huang ZaiYin,
Tong ZhangFa,
Chen Jie,
Liang RongLan
Publication year - 2007
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.200790020
Subject(s) - chemistry , enthalpy , decomposition , kinetics , order of reaction , magnesium , standard enthalpy of reaction , calorimeter (particle physics) , isothermal process , nuclear chemistry , inorganic chemistry , reaction rate constant , thermodynamics , organic chemistry , physics , quantum mechanics , detector , electrical engineering , engineering
Ammonium magnesium phosphate monohydrate NH 4 MgPO 4 ·H 2 O was prepared via solid state reaction at room temperature and characterized by XRD, FT‐IR and SEM. Thermochemical study was performed by an isoperibol solution calorimeter, non‐isothermal measurement was used in a multivariate non‐linear regression analysis to determine the kinetic reaction parameters. The results show that the molar enthalpy of reaction above is (28.795±0.182) kJ/mol (298.15 K), and the standard molar enthalpy of formation of the title complex is (−2185.43±13.80) kJ/mol (298.15 K). Kinetics analysis shows that the second decomposition of NH 4 MgPO 4 ·H 2 O acts as a double‐step reaction:an n th‐order reaction ( F n ) with n= 4.28, E 1 =147.35 kJ/mol, A 1 =3.63×10 13 s −1 is followed by a second‐order reaction ( F 2 ) with E 2 =212.71 kJ/mol, A 2 =1.82×10 18 s −1 .