Thermal Decomposition Procedures and Thermodynamic Properties of Some Transition Metal Complexes with 2-(2-Hydroxyphenyl)Benzothiazolate

2010 ◽  
Vol 55 (9) ◽  
pp. 3364-3368 ◽  
Author(s):  
Fei Liu ◽  
Lijun Wang ◽  
Xia Li ◽  
Jinting Tan ◽  
Qi Wu ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Transition Metal ◽  
Thermodynamic Properties ◽  
Metal Complexes ◽  
Transition Metal Complexes

Chelating agents in high temperature aqueous chemistry. 2. The thermal decomposition of some transition metal complexes of nitrilotriacetate (NTA)

1977 ◽  
Vol 55 (10) ◽  
pp. 1770-1776 ◽  
Author(s):  
Meindert Booy ◽  
Thomas Wilson Swaddle
Keyword(s):  
Thermal Decomposition ◽  
High Temperature ◽  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Half Life ◽  
Chelating Agents ◽  
Nuclear Reactors ◽  
Hydrothermal Conditions ◽  
Mechanism Of Decomposition

The kinetics and mechanism of decomposition of NTA complexes of FeIII, FeII, CoII, NiII, and CuII under hydrothermal conditions (425–573 K) have been examined. The relative rates at 573 K are CoIINTA− < NTA3−[Formula: see text] < NiIINTA− < FeIIINTA0 < H3NTA0 < CuIINTA− < H4NTA+. Aqueous CoIINTA− and FeIINTA−, like NTA3−, decomposed at 573 K by decarboxylation, precipitating Co(OH)2 and Fe3O4 respectively; NiIINTA− precipitated Ni(OH)2 initially but subsequently Ni metal. At 530 K, FeIIINTA0 solutions precipitated FeII3(NTA)2•H2O, but at higher temperatures Fe3O4 formed, the NTA ligand being reduced to HCHO and iminodiacetate (IDA) rather than decarboxylated. Similarly, CuIINTA−gave IDA and HCHO at temperatures as low as 425 K, forming first CuI (which precipitated as CuCl in the presence of Cl−) and then metallic Cu. The applicability of NTA to corrosion control in boilers and to 60Co removal from water-cooled nuclear reactors is briefly considered. The half-life of FeIIINTA in the hydrosphere is estimated at 80 years (cf. 8 × 106 years for free NTA), in the absence of photolysis or biodégradation.

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