The thermal decomposition of copper (II) oxalate revisited
- Lamprecht, Emmanuel, Watkins, Gareth M, Brown, Michael E
- Authors: Lamprecht, Emmanuel , Watkins, Gareth M , Brown, Michael E
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6577 , http://hdl.handle.net/10962/d1004140
- Description: DSC, TG and TG-FT-IR, and XRPD have been used to examine the effects of supposedly inert atmospheres of argon and nitrogen on the mechanism of the thermal decomposition of copper(II) oxalate. The DSC curves in pure argon at 10 °C min[superscript −1] show a broad endotherm with onset at about 280 °C and maximum at about 295 °C. In mixtures of argon and nitrogen, as the proportion of argon gas is decreased, the endothermic character of the decomposition decreases until, when nitrogen is the main component, the decomposition exhibits a complex broad exothermic character. XRPD studies showed that, regardless of the proportions of nitrogen and argon, the DSC residues consisted of mainly copper metal with small amounts of copper(I) oxide (cuprite) and, under some conditions, traces of copper(II) oxide (tenorite). Various explanations for this behaviour are discussed and a possible answer lies in the disproportionation of CO[subscript 2](g) to form small quantities of O[subscript 2](g) or monatomic oxygen. The possibility exists that the exothermicity in nitrogen could be explained by reaction of the nitrogen with atomic oxygen to form N[subscript 2]O(g), but this product could not be detected using TG-FT-IR.
- Full Text:
- Date Issued: 2006
- Authors: Lamprecht, Emmanuel , Watkins, Gareth M , Brown, Michael E
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6577 , http://hdl.handle.net/10962/d1004140
- Description: DSC, TG and TG-FT-IR, and XRPD have been used to examine the effects of supposedly inert atmospheres of argon and nitrogen on the mechanism of the thermal decomposition of copper(II) oxalate. The DSC curves in pure argon at 10 °C min[superscript −1] show a broad endotherm with onset at about 280 °C and maximum at about 295 °C. In mixtures of argon and nitrogen, as the proportion of argon gas is decreased, the endothermic character of the decomposition decreases until, when nitrogen is the main component, the decomposition exhibits a complex broad exothermic character. XRPD studies showed that, regardless of the proportions of nitrogen and argon, the DSC residues consisted of mainly copper metal with small amounts of copper(I) oxide (cuprite) and, under some conditions, traces of copper(II) oxide (tenorite). Various explanations for this behaviour are discussed and a possible answer lies in the disproportionation of CO[subscript 2](g) to form small quantities of O[subscript 2](g) or monatomic oxygen. The possibility exists that the exothermicity in nitrogen could be explained by reaction of the nitrogen with atomic oxygen to form N[subscript 2]O(g), but this product could not be detected using TG-FT-IR.
- Full Text:
- Date Issued: 2006
100 years of chemistry at Rhodes University
- Brown, Michael E, Eve, Desmond John, Kaye, Perry T, Rivett, Douglas E A, Watkins, Gareth M
- Authors: Brown, Michael E , Eve, Desmond John , Kaye, Perry T , Rivett, Douglas E A , Watkins, Gareth M
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6564 , http://hdl.handle.net/10962/d1004123
- Description: The history of Grahamstown is well documented and two books deal with the history of Rhodes University.1,2 Although the Chemistry Department was one of the founding departments, coverage in the official histories is minimal and sometimes inaccurate or misleading. The Rhodes University Centenary is an appropriate time to look back on some of the achievements of the department and some of its graduates over the past 100 years.
- Full Text:
- Date Issued: 2004
- Authors: Brown, Michael E , Eve, Desmond John , Kaye, Perry T , Rivett, Douglas E A , Watkins, Gareth M
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6564 , http://hdl.handle.net/10962/d1004123
- Description: The history of Grahamstown is well documented and two books deal with the history of Rhodes University.1,2 Although the Chemistry Department was one of the founding departments, coverage in the official histories is minimal and sometimes inaccurate or misleading. The Rhodes University Centenary is an appropriate time to look back on some of the achievements of the department and some of its graduates over the past 100 years.
- Full Text:
- Date Issued: 2004
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