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Aluminium triflate as a Lewis acid catalyst in some epoxide and aromatic transformations

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dc.contributor.advisor Prof. D.B.G. Williams en_US
dc.contributor.author Lawton, Michelle Claire
dc.date.accessioned 2012-03-14T05:54:10Z
dc.date.available 2012-03-14T05:54:10Z
dc.date.issued 2012-03-14
dc.date.submitted 2005
dc.identifier.uri http://hdl.handle.net/10210/4536
dc.description M.Sc. en_US
dc.description.abstract Lewis acids play an important role in catalysis; they are associated with mild conditions, high selectivities and unique reactivities. Traditional Lewis acids such as AlCb and BF3 successfully catalyse such well known reactions as the Friedel-Crafts acylation reaction, Aldol condensation reactions and many more. These catalysts, however, must be used in a stoichiometric amount and are destroyed during the aqueous workup procedures. Lately, there has been a lot of interest in the role of metal triflate as Lewis acid catalysts. They were found to be effective in a wide range of reactions when used in catalytic amounts. They were also found to be recyclable and reusable without the loss of activity. Most of this research has been centred around the lanthanide triflates as well as scandium, bismuth and yttrium triflates. Very little research has been done using aluminium triflate and this triflate forms the focus ofthis study. The work contained in this dissertation demonstrates that Al(OTf)3 is an efficient catalyst for the ring opening of a variety of epoxides by alcohols when present in only ppm amounts. These reactions provided products in very high yields and selectivities. Simple acyclic and cyclic epoxides readily underwent ring opening reactions with a range of alcohols, typically providing the monoglycol ethers as single compounds (from the cyclic epoxides) or as mixtures of the two possible glycol monoethers (from the acyclic epoxides). In the case of styrene oxide, essentially a single compound was isolated. In contrast, the glycidyl ethers required slightly higher catalyst loadings before similar rates and conversions to product were observed. Additionally, an interesting selectivity was observed in the orientation of the attack of the alcohol onto the epoxide, which appeared to be chelation controlled. Similarly, the Al(OTf)3 also catalysed the aminolysis of a variety of epoxides. These reactions proceeded smoothly with catalytic amounts of the triflate present, and served to nicely highlight the role that steric and electronic factors played in these reactions. A preliminary study was carried out into the efficacy of Al(OTf)3 as a catalyst for Friedel-Crafts acylation and aromatic nitration reactions. From these studies it is evident that the Al(OTf)3 is indeed an effective catalyst for these reactions when present in substoichiometric levels and further studies will be carried out in this area in the future. en_US
dc.language.iso en en_US
dc.subject Lewis acids en_US
dc.subject Aluminum en_US
dc.subject Alcoholysis en_US
dc.subject Epoxy compounds en_US
dc.subject Catalysts en_US
dc.subject Aromatic compounds en_US
dc.subject Substitution reactions en_US
dc.title Aluminium triflate as a Lewis acid catalyst in some epoxide and aromatic transformations en_US
dc.type Thesis en_US

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