Synthesis, characterization and thermal behaviour of solid 2-methoxycinnamylidenepyruvate of some bivalent metal ions in CO2 and N2 atmospheres

C T De Carvalho,E Y Ionashiro,A B Siqueira,M Ionashiro

doi:10.1590/s0100-46702010000400007

Abstract

Solid State M-2-MeO-CP compounds, where M stands for bivalent metals (Mn, Fe, Co, Ni, Cu and Zn) and 2-MeO-CP is 2-methoxycinnamylidenepyruvate, were synthesized. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), elemental analysis and complexometry were used to establish the stoichiometry and to study the thermal behaviour of these compounds in CO2 and N2 atmospheres. The results were consistent with the general formula: M(L)2∙H2O. In both atmospheres (CO2, N2) the thermal decomposition occurs in consecutive steps which are characteristic of each compound. For CO2 atmosphere the final residues were: Mn3O4, Fe3O4, Co3O4, NiO, Cu2O and ZnO, while under N2 atmosphere the thermal decomposition is still observed at 1000 º C.

Highlights

Several metal-ion complexes of phenyl-substituted derivatives of cinnamylidenepyruvate, C6H5(CH)4-COCOO-(CP), have been investigated in aqueous solutions [1,2] and in the solid state [3,4,5,6,7,8,9,10,11]
The works report the synthesis and investigation of the compounds in the solid state by means of thermogravimetry, differential thermal analysis (DTA), differential scanning calorimetry (DSC), and other methods of analysis.Establishment of the stoichiometry and the details of the thermal decomposition were the main purpose of the studies
These results permitted to establish the stoichiometry of the compounds, which is in agreement with the general formula M(L)2 .nH2O, where M represents bivalent Mn, Fe, Co, Ni, Cu and Zn, L is 2-methoxycinnamylidene pyruvate and n=2

Summary

Introduction

Several metal-ion complexes of phenyl-substituted derivatives of cinnamylidenepyruvate, C6H5(CH)4-COCOO-(CP), have been investigated in aqueous solutions [1,2] and in the solid state [3,4,5,6,7,8,9,10,11]. The works report the synthesis and investigation of the compounds in the solid state by means of thermogravimetry, differential thermal analysis (DTA), differential scanning calorimetry (DSC), and other methods of analysis.Establishment of the stoichiometry and the details of the thermal decomposition were the main purpose of the studies. The thermal behaviour of 2methoxycinnamylidenepyruvate of Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II) in CO2 and N2 atmospheres have not been reported. The objective of the present research was to prepare sodium2-methoxycinnamylidenepyruvate and 2-methoxycinnamylidenepyruvate of some bivalent metal ions in the solid state and too investigated by means of complexometry, elemental analysis, simultaneous thermogravimetry and differential thermal analysis (TG-DTA) and differential scanning calorimetry (DSC). The results allowed us to acquire information concerning the thermal behaviour in an atmosphere of CO2 and N2

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Results

Conclusion