Alkane oxidation using metallophthalocyanine as homogeneous catalysts
- Authors: Grootboom, Natasha Denise
- Date: 2002
- Subjects: Oxidation , Alkanes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4449 , http://hdl.handle.net/10962/d1007794
- Description: Iron polychlorophthalocyanine (FePc(Cl)₁₆) and tetrasulfophthalocyanine ([M¹¹TSPc]⁴) complexes of iron, cobalt and manganese are employed as catalysts for the oxidation of cyclohexane using tert-butyl hydroperoxide (TBHP), chloroperoxybenzoic acid (CPBA) and hydrogen peroxide as oxidants. Catalysis using the FePc(Cl)₁₆ was performed in a dimethylformamide:dichloromethane (3 :7) solvent mixture. For the [Fe¹¹TSPc]⁴⁻, [Co¹¹TSPc]⁻ and [Mn¹¹TSPc]⁴⁻catalysts, a water:methanol (1:9) mixture was employed. The products of the catalysis are cyclohexanone, cyclohexanol and cyclohexanediol. The relative percentage yields, percentage selectivity and overall percentage conversion of the products depended on types of oxidant, or catalyst, concentrations of substrate or catalysts and temperature. TBHP was found to be the best oxidant since minimal destruction of the catalyst and higher selectivity in the products were observed when this oxidant was employed. Of the four catalysts investigated [Fe¹¹TSPc]⁴⁻ yielded the highest overall percentage conversion of 20%.The mechanism of the oxidation of cyclohexane in the presence of the FePc(Cl)₁₆ and [M¹¹TSPc]⁴⁻ involves the oxidation of these catalysts, forming an Fe(IlI) phthalocyanine species as an intermediate. Electrocatalysis using [Co¹¹TSPc]⁴⁻ as catalyst, employed an aqueous pH 7 buffer medium for electro-oxidation of 4-pentenoic acid. An enone is suggested as the only oxidation product of 4-pentenoic acid. No degradation of [Co¹¹TSPc]⁴⁻ was observed during the electrocatalytic process. In this process water was used as a source of oxygen therefore eliminating the production of by products from oxidant as in the case of TBHP and CPBA. This system was studied In an attempt to set up conditions for alkane electrocatalytic oxidation.
- Full Text:
- Authors: Grootboom, Natasha Denise
- Date: 2002
- Subjects: Oxidation , Alkanes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4449 , http://hdl.handle.net/10962/d1007794
- Description: Iron polychlorophthalocyanine (FePc(Cl)₁₆) and tetrasulfophthalocyanine ([M¹¹TSPc]⁴) complexes of iron, cobalt and manganese are employed as catalysts for the oxidation of cyclohexane using tert-butyl hydroperoxide (TBHP), chloroperoxybenzoic acid (CPBA) and hydrogen peroxide as oxidants. Catalysis using the FePc(Cl)₁₆ was performed in a dimethylformamide:dichloromethane (3 :7) solvent mixture. For the [Fe¹¹TSPc]⁴⁻, [Co¹¹TSPc]⁻ and [Mn¹¹TSPc]⁴⁻catalysts, a water:methanol (1:9) mixture was employed. The products of the catalysis are cyclohexanone, cyclohexanol and cyclohexanediol. The relative percentage yields, percentage selectivity and overall percentage conversion of the products depended on types of oxidant, or catalyst, concentrations of substrate or catalysts and temperature. TBHP was found to be the best oxidant since minimal destruction of the catalyst and higher selectivity in the products were observed when this oxidant was employed. Of the four catalysts investigated [Fe¹¹TSPc]⁴⁻ yielded the highest overall percentage conversion of 20%.The mechanism of the oxidation of cyclohexane in the presence of the FePc(Cl)₁₆ and [M¹¹TSPc]⁴⁻ involves the oxidation of these catalysts, forming an Fe(IlI) phthalocyanine species as an intermediate. Electrocatalysis using [Co¹¹TSPc]⁴⁻ as catalyst, employed an aqueous pH 7 buffer medium for electro-oxidation of 4-pentenoic acid. An enone is suggested as the only oxidation product of 4-pentenoic acid. No degradation of [Co¹¹TSPc]⁴⁻ was observed during the electrocatalytic process. In this process water was used as a source of oxygen therefore eliminating the production of by products from oxidant as in the case of TBHP and CPBA. This system was studied In an attempt to set up conditions for alkane electrocatalytic oxidation.
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South African memoirs in a decade of transition: Athol Fugard's Cousins (1994), J.M. Coetzee's Boyhood (1997), and Breyten Breytenbach's Dog Heart (1999)
- Authors: Roux, Christine Ann
- Date: 2002
- Subjects: Autobiography , Fugard, Athol , Coetzee, J. M., 1940 , Breytenbach, Breyten
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2191 , http://hdl.handle.net/10962/d1002233 , Autobiography , Fugard, Athol , Coetzee, J. M., 1940 , Breytenbach, Breyten
- Description: This thesis examines three South African memoirs using M. M. Bakhtin’s theories of the dialogical relationship in language and literature. By offering an alternative to a postmodern or multicultural interpretation of autobiographies, Bakhtin’s precepts, that define a dialogic, help to reframe a way of discussing memoirs and avoiding dead-ends previously arrived at by essayists in James Olney’s 1980 collection. Bakhtin’s ideas discussed here, which include the “once-occurrent moment”, “architectonic contraposition”, ”emotional-volitional tone”, “alibi”, “non-alibi”, and “centripetal” and “centrifugal” force, help to rebuild a discussion based on temporary and evolving self truth rather than fiction, the postmodern interpretation, or confession, the new-age secular spiritualism based on multicultural and politically correct standards. For this, each author’s memoir had to be examined separately and a conclusion was arrived at through inductive analysis. Rather than try to find similar characteristics, I focused on what made each memoir different and unique. Janet Varner Gunn’s Autobiography: Toward A Poetics of Experience (1982) refocused the debate over autobiography on process. The question, what steps did each author take toward writing about himself, led the discussion to an examination of the priorities each author exemplified. Beginning with Fugard who emphasized spatial, concrete, and sensory detail to help him contain his emotional life, the thesis moves on to an examination of Coetzee’s sense of justice. From the physical and intellectual world follows Breytenbach’s spiritual space-making. In each memoir, control of space is evident on different levels of experience. Articulating space inevitably leads to a discussion of boundaries. Here, Charles Taylor’s emphasis on the modern self’s need to articulate a horizon or a framework is helpful in generalizing the effect of the autobiographical process. The conclusion reached is that autobiography is inherently centrifugal: it moves away from the center of cultural thinking because its “truth” bolsters itself on dialogical process which does not depend on a fixed authority but rather on communicative exchange. As an example of exchange, autobiography’s central truth is that it returns to a “unique point of origin”, namely the self, only to reconnect to the other in a potentially eternal exchange of responsiveness moving away from the center.
- Full Text:
- Authors: Roux, Christine Ann
- Date: 2002
- Subjects: Autobiography , Fugard, Athol , Coetzee, J. M., 1940 , Breytenbach, Breyten
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2191 , http://hdl.handle.net/10962/d1002233 , Autobiography , Fugard, Athol , Coetzee, J. M., 1940 , Breytenbach, Breyten
- Description: This thesis examines three South African memoirs using M. M. Bakhtin’s theories of the dialogical relationship in language and literature. By offering an alternative to a postmodern or multicultural interpretation of autobiographies, Bakhtin’s precepts, that define a dialogic, help to reframe a way of discussing memoirs and avoiding dead-ends previously arrived at by essayists in James Olney’s 1980 collection. Bakhtin’s ideas discussed here, which include the “once-occurrent moment”, “architectonic contraposition”, ”emotional-volitional tone”, “alibi”, “non-alibi”, and “centripetal” and “centrifugal” force, help to rebuild a discussion based on temporary and evolving self truth rather than fiction, the postmodern interpretation, or confession, the new-age secular spiritualism based on multicultural and politically correct standards. For this, each author’s memoir had to be examined separately and a conclusion was arrived at through inductive analysis. Rather than try to find similar characteristics, I focused on what made each memoir different and unique. Janet Varner Gunn’s Autobiography: Toward A Poetics of Experience (1982) refocused the debate over autobiography on process. The question, what steps did each author take toward writing about himself, led the discussion to an examination of the priorities each author exemplified. Beginning with Fugard who emphasized spatial, concrete, and sensory detail to help him contain his emotional life, the thesis moves on to an examination of Coetzee’s sense of justice. From the physical and intellectual world follows Breytenbach’s spiritual space-making. In each memoir, control of space is evident on different levels of experience. Articulating space inevitably leads to a discussion of boundaries. Here, Charles Taylor’s emphasis on the modern self’s need to articulate a horizon or a framework is helpful in generalizing the effect of the autobiographical process. The conclusion reached is that autobiography is inherently centrifugal: it moves away from the center of cultural thinking because its “truth” bolsters itself on dialogical process which does not depend on a fixed authority but rather on communicative exchange. As an example of exchange, autobiography’s central truth is that it returns to a “unique point of origin”, namely the self, only to reconnect to the other in a potentially eternal exchange of responsiveness moving away from the center.
- Full Text:
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