Thermal Decomposition of Chelating Agents and a New Mechanism of Formation Damage

2013 ◽  
Author(s):  
Khatere Sokhanvarian ◽  
Hisham Nasr-El-Din ◽  
Corine De-Wolf
Keyword(s):  
Thermal Decomposition ◽  
Chelating Agents ◽  
Formation Damage ◽  
Mechanism Of Formation

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.

STEROIDS: II. REACTION OF AMINES WITH CHOLESTERYL CHLOROFORMATE AND PYROLYSIS OF N-BENZYL CHOLESTERYL CARBAMATE

1953 ◽  
Vol 31 (7) ◽  
pp. 688-693 ◽  
Author(s):  
A. F. McKay ◽  
G. R. Vavasour
Keyword(s):  
Carbon Dioxide ◽  
Thermal Decomposition ◽  
Aqueous Solutions ◽  
Mechanism Of Formation

Cholesteryl chloroformate can be used to isolate small amounts of amines from aqueous solutions as N-substituted cholesteryl carbamates. These derivatives are easily isolated and identified. Their possible use for, the identification of amines obtained in degradative studies is discussed. The thermal decomposition of N-benzyl cholesteryl carbamate gives carbon dioxide, cholesterol, cholest-3,5-diene, and sym-dibenzylurea. A mechanism of formation of these products is discussed.

A modified citrate gel route for the synthesis of phase pure Bi2Sr2CaCu2O8 superconductor

1994 ◽  
Vol 9 (6) ◽  
pp. 1357-1362 ◽  
Author(s):  
Sujatha P. Devi ◽  
H.S. Maiti
Keyword(s):  
Thermal Decomposition ◽  
Transition Temperature ◽  
Combustion Process ◽  
Superconducting Phase ◽  
Mechanism Of Formation ◽  
Sharp Transition ◽  
Simple Method ◽  
Phase Pure ◽  
Plausible Mechanism

A simple method for the bulk synthesis of 80 K bismuth-based superconducting phase (2212) is described. It employs a modified citrate gel route giving rise to an auto-ignited combustion process. The precursor ash obtained after combustion is further calcined at 800 °C to produce the desired superconducting powder with excellent homogeneity and fineness, leading to good sinterability and fairly sharp transition temperature. For a particular citrate-nitrate ratio, the nature of combustion of the gels containing two different bases has been compared. The thermal decomposition characteristics of the gels and the plausible mechanism of formation of the superconducting phase are also described.

scholarly journals Role of CA-EDTA on the Synthesizing Process of Cerate-Zirconate Ceramics Electrolyte

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Nur Athirah Abdullah ◽  
Sharizal Hasan ◽  
Nafisah Osman
Keyword(s):  
Thermal Decomposition ◽  
Citric Acid ◽  
Chelating Agents ◽  
Sol Gel ◽  
Decomposition Temperature ◽  
Metal Nitrate ◽  
Molar Ratio ◽  
Calcination Temperatures ◽  
Decomposition Behaviour

The role of a combination between citric acid (CA) and ethylenediaminetetra acetic acid (EDTA) as chelating agents in preparation of BaCe0.54Zr0.36Y0.1O2.95powder by a modified sol-gel method is reported. The precursor solutions were prepared from metal nitrate salts (M+), chelating agents (C), and ethylene glycol (EG) at molar ratio of M+ : C : EG = 3 : 2 : 3. Chemical and phase transformation of samples during thermal decomposition were analyzed by thermogravimetric analysis (TGA) and Fourier transform infrared (FTIR) spectroscopy. TGA results show that the sample prepared by a combination of CA-EDTA exhibited the lowest thermal decomposition temperature,Ttdsince there was no significant weight loss after 750°C. After calcined at 1100°C, the carbonates residue remained in the samples as proven by FTIR results. It was found that the used combination of CA-EDTA acts as a better combustion reagent to increase the reaction rate and influence the thermal decomposition behaviour compared to a single citric acid and EDTA, respectively. Apparently, calcination temperatures above 1100°C are needed to produce a pure perovskitic BaCe0.54Zr0.36Y0.1O2.95.

scholarly journals The Effect of Various Chelating Agents on the Thermal Decomposition of Cerate-Zirconate Ceramics Powder

2012 ◽  
Vol 3 ◽  
pp. 28-32 ◽  
Author(s):  
N.A. Abdullah ◽  
N. Osman ◽  
S. Hasan ◽  
R.M. Nordin
Keyword(s):  
Thermal Decomposition ◽  
Chelating Agents

New Formulation for Sandstone Acidizing That Eliminates Sand Production Problems in Oil and Gas Sandstone Reservoirs

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Mohamed Mahmoud
Keyword(s):  
Acetic Acid ◽  
Clay Minerals ◽  
Clay Mineral ◽  
Potassium Carbonate ◽  
Chelating Agents ◽  
Mineral Dissolution ◽  
Formation Damage ◽  
Dimensionless Number ◽  
Sand Production ◽  
Sandstone Rock

The sandstone rocks' integrity and consolidation may be highly affected by the type and the strength of the stimulation fluids. Strong acids such as HF/HCl impair the rock consolidation. The reduction in the sandstone rock consolidation will trigger the sand production. Sand causes erosion of downhole and surface equipment especially when it is produced with high gas flow rates. In this study, gentle stimulation fluids for sandstone that consists of chelating agents and catalyst were proposed. The chelating agents are diethylene triamine penta acetic acid (DTPA) and ethylene diamine tetra acetic acid (EDTA). This is the first time to introduce a catalyst (potassium carbonate) in sandstone acidizing. Potassium carbonate was found to work as a clay stabilizer and catalyst that enhances the dissolution of chlorite clay mineral in the sandstone rock. The objective of introducing the catalyst is to enhance the solubility of the insoluble minerals such as chlorite clay minerals. The change in the mechanical properties of sandstone rocks (Bandera and Berea) was evaluated. The possibility of the formation damage after using seawater-based chelating agents was investigated and compared to HF/HCl mud acid. Coreflooding experiments were conducted to evaluate the effect of these fluids on the rock integrity. Computed tomography (CT) scanner was used to assess the formation damage. Different models were used to predict the sand production possibility after the stimulation with chelating agent/catalyst, and this was compared to the HF/HCl mud acid. The results showed that the permeability of sandstone core increased after acidizing. The reduction in CT-number after acidizing confirmed that no formation damage occurred. Rock mechanics evaluation showed no major changes occurred in the rock moduli and no sand production was observed. The model results showed that using chelating gents to stimulate Berea (BR) and Bandera (BN) sandstone cores did not cause sand production. Applying the same models for cores stimulated by HF/HCl acids indicated high possibility of sand production. The addition of potassium carbonate to DTPA chelating agents enhanced the chlorite clay mineral dissolution based on the inductively coupled plasma (ICP) analysis. Potassium carbonate as a catalyst did not affect the sandstone integrity because it only enhanced the dissolution of chlorite clay minerals (selective dissolution) and did not affect the solubility of carbonate minerals which are the primary cementing materials in the sandstone cores. A new dimensionless number was developed that describes the relation between the number of pore volumes (PVs) contacted the rock and the radial distance from the wellbore.

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