Use of water-soluble phosphine ligands in heterogeneous hydroformylation catalysis : application to long-chain 1-alkenes

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dc.contributor.advisorKoch, Klaus Ren_ZA
dc.contributor.authorDu Toit, Judith G Oen_ZA
dc.date.accessioned2016-10-03T04:10:05Z
dc.date.available2016-10-03T04:10:05Z
dc.date.issued1994en_ZA
dc.description.abstractThe two-phase rhodium-tri(m-sulfonatophenyl)phosphine (Rh-TPPTS) system for the hydroformylation of 1-octene, 1-decene, and 1-dodecene to the corresponding aldehydes, has been investigated. Due to the two distinct phases - the catalytic species in the aqueous phase and the products and reactants in the organic phase - the separation of the catalyst was easily facilitated. A comparison was made of the activity, selectivity towards linear aldehydes, and catalyst lifetime of two systems where i) the active catalytic species were generated in situ from rhodium trichloride (RhCl₃.3H₂O) and excess phosphine ligand (TPPTS) under mild hydroformylation conditions (5 MPa H₂/CO (1:1); 100 °C); and ii) where the rhodium(I) complex, RhH(CO)(TPPTS)₃ is used as the catalyst precursor. The former system was found to be superior in activity and selectivity to that of the latter, achieving fairly high conversions of ca. 60% for the hydroformylation of 1-octene, with n:iso ratios of up to 16:1 for a catalyst composition a Rh:P ratio of 1:30. Unfortunately low conversions of ca. 10% for the hydroformylation of 1-decene and ca. 4% for that of 1-dodecene resulted under the same conditions. While the reasons for the drastic decrease in conversion for C₁₀ and C₁₂ alkenes is not completely clear, this poor conversion is attributed to the extremely low solubility of the long-chain 1-alkenes in the aqueous phase. Under certain optimum conditions (Rh:P ≥ l :20), virtually no leeching of rhodium into the organic phase was detected. A ³¹P NMR spectroscopic study was undertaken in an attempt to ascertain the nature and distribution of rhodium tertiary-phosphine complexes in the aqueous phase before and after the mixture was subjected to standard hydroformylation conditions.en_ZA
dc.identifier.apacitationDu Toit, J. G. O. (1994). <i>Use of water-soluble phosphine ligands in heterogeneous hydroformylation catalysis : application to long-chain 1-alkenes</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Chemistry. Retrieved from http://hdl.handle.net/11427/22055en_ZA
dc.identifier.chicagocitationDu Toit, Judith G O. <i>"Use of water-soluble phosphine ligands in heterogeneous hydroformylation catalysis : application to long-chain 1-alkenes."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Chemistry, 1994. http://hdl.handle.net/11427/22055en_ZA
dc.identifier.citationDu Toit, J. 1994. Use of water-soluble phosphine ligands in heterogeneous hydroformylation catalysis : application to long-chain 1-alkenes. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Du Toit, Judith G O AB - The two-phase rhodium-tri(m-sulfonatophenyl)phosphine (Rh-TPPTS) system for the hydroformylation of 1-octene, 1-decene, and 1-dodecene to the corresponding aldehydes, has been investigated. Due to the two distinct phases - the catalytic species in the aqueous phase and the products and reactants in the organic phase - the separation of the catalyst was easily facilitated. A comparison was made of the activity, selectivity towards linear aldehydes, and catalyst lifetime of two systems where i) the active catalytic species were generated in situ from rhodium trichloride (RhCl₃.3H₂O) and excess phosphine ligand (TPPTS) under mild hydroformylation conditions (5 MPa H₂/CO (1:1); 100 °C); and ii) where the rhodium(I) complex, RhH(CO)(TPPTS)₃ is used as the catalyst precursor. The former system was found to be superior in activity and selectivity to that of the latter, achieving fairly high conversions of ca. 60% for the hydroformylation of 1-octene, with n:iso ratios of up to 16:1 for a catalyst composition a Rh:P ratio of 1:30. Unfortunately low conversions of ca. 10% for the hydroformylation of 1-decene and ca. 4% for that of 1-dodecene resulted under the same conditions. While the reasons for the drastic decrease in conversion for C₁₀ and C₁₂ alkenes is not completely clear, this poor conversion is attributed to the extremely low solubility of the long-chain 1-alkenes in the aqueous phase. Under certain optimum conditions (Rh:P ≥ l :20), virtually no leeching of rhodium into the organic phase was detected. A ³¹P NMR spectroscopic study was undertaken in an attempt to ascertain the nature and distribution of rhodium tertiary-phosphine complexes in the aqueous phase before and after the mixture was subjected to standard hydroformylation conditions. DA - 1994 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1994 T1 - Use of water-soluble phosphine ligands in heterogeneous hydroformylation catalysis : application to long-chain 1-alkenes TI - Use of water-soluble phosphine ligands in heterogeneous hydroformylation catalysis : application to long-chain 1-alkenes UR - http://hdl.handle.net/11427/22055 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/22055
dc.identifier.vancouvercitationDu Toit JGO. Use of water-soluble phosphine ligands in heterogeneous hydroformylation catalysis : application to long-chain 1-alkenes. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Chemistry, 1994 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/22055en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Chemistryen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherChemistryen_ZA
dc.titleUse of water-soluble phosphine ligands in heterogeneous hydroformylation catalysis : application to long-chain 1-alkenesen_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMScen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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