Production of mid-chain branched detergent-range olefins over shape-selective acid catalysts

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dc.contributor.advisorFletcher, Jacken_ZA
dc.contributor.authorSumani, Mmontshi Lebohang Oliveren_ZA
dc.date.accessioned2015-01-02T09:08:21Z
dc.date.available2015-01-02T09:08:21Z
dc.date.issued2006en_ZA
dc.descriptionIncludes bibliographical references (leaves 78-83).en_ZA
dc.description.abstractFor the purpose of producing mid-chain mono-methyl branched olefins, a range of acid catalysts (MFI, BEA, TON and amorphous silica-alumina) were screened for the dimerization of 1-hexene, under generally mild conditions, viz. 150 - 170°C, 20 - 40 bar and 1 - 4h-1 WHSV. It was postulated that shape-selective catalysts with defined pore sizes might improve selectivity towards mid-chain mono-methyl branched olefins. Such olefins are potential feedstocks for selectively branched detergents which have improved surfactant properties while retaining good biodegradability. NMR and GC-MS analyses of hydrogenated dimer product fractions indicated that all catalysts produce branched products, and that these products are predominantly multi-branched (i.e. with two or more branches per C12 molecule). Overall, the findings of this study suggest a similar degree of branching of two for all catalysts. Selective poisoning of the external surface of the MFI-90 catalyst using bulky bases effectively eliminated the catalytic activity, suggesting that in the case of MFI zeolite, the hexene dimerization reaction occurs largely (if not exclusively) on the external crystal surfaces which are not shape-selective.In conclusion, BEA and amorphous silica-alumina pore being too large to induce shape selectivity and MFI and TON dimerization being limited to the external, non-selective, surface sites, the production of mono-methyl branched 1-hexene dimers was not accomplished.en_ZA
dc.identifier.apacitationSumani, M. L. O. (2006). <i>Production of mid-chain branched detergent-range olefins over shape-selective acid catalysts</i>. (Thesis). University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Chemical Engineering. Retrieved from http://hdl.handle.net/11427/10977en_ZA
dc.identifier.chicagocitationSumani, Mmontshi Lebohang Oliver. <i>"Production of mid-chain branched detergent-range olefins over shape-selective acid catalysts."</i> Thesis., University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Chemical Engineering, 2006. http://hdl.handle.net/11427/10977en_ZA
dc.identifier.citationSumani, M. 2006. Production of mid-chain branched detergent-range olefins over shape-selective acid catalysts. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Sumani, Mmontshi Lebohang Oliver AB - For the purpose of producing mid-chain mono-methyl branched olefins, a range of acid catalysts (MFI, BEA, TON and amorphous silica-alumina) were screened for the dimerization of 1-hexene, under generally mild conditions, viz. 150 - 170°C, 20 - 40 bar and 1 - 4h-1 WHSV. It was postulated that shape-selective catalysts with defined pore sizes might improve selectivity towards mid-chain mono-methyl branched olefins. Such olefins are potential feedstocks for selectively branched detergents which have improved surfactant properties while retaining good biodegradability. NMR and GC-MS analyses of hydrogenated dimer product fractions indicated that all catalysts produce branched products, and that these products are predominantly multi-branched (i.e. with two or more branches per C12 molecule). Overall, the findings of this study suggest a similar degree of branching of two for all catalysts. Selective poisoning of the external surface of the MFI-90 catalyst using bulky bases effectively eliminated the catalytic activity, suggesting that in the case of MFI zeolite, the hexene dimerization reaction occurs largely (if not exclusively) on the external crystal surfaces which are not shape-selective.In conclusion, BEA and amorphous silica-alumina pore being too large to induce shape selectivity and MFI and TON dimerization being limited to the external, non-selective, surface sites, the production of mono-methyl branched 1-hexene dimers was not accomplished. DA - 2006 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2006 T1 - Production of mid-chain branched detergent-range olefins over shape-selective acid catalysts TI - Production of mid-chain branched detergent-range olefins over shape-selective acid catalysts UR - http://hdl.handle.net/11427/10977 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/10977
dc.identifier.vancouvercitationSumani MLO. Production of mid-chain branched detergent-range olefins over shape-selective acid catalysts. [Thesis]. University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Chemical Engineering, 2006 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/10977en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Chemical Engineeringen_ZA
dc.publisher.facultyFaculty of Engineering and the Built Environment
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherApplied Scienceen_ZA
dc.titleProduction of mid-chain branched detergent-range olefins over shape-selective acid catalystsen_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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