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Mesoporous silica supported catalysts for carbon-carbon bond forming reactions

Tamuang, Suparb (2012)
Ph.D. thesis, University of Birmingham.

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Abstract

The synthesis and characterisation of well-ordered mesoporous silicas, MCM-41, MCM-48, SBA-1, and SBA-2 has been carried out successfully. All of the synthesised materials possess the expected characteristic ordering as confirmed by powder X-ray diffraction. Moreover, surface modification of these mesoporous silicas had also been achieved through the incorporation of alkylamine groups and attachment of an asymmetric organometallic nickel-salen complex.
The catalytic activity of the amino and nickel complex-modified mesoporous silica materials was examined for carbon-carbon bond forming reactions; Knoevenagel condensation of benzaldehyde and ethylcyanoacetate, and Kumada-Corriu coupling reaction between an organobromide and Grignard reagent, respectively. All the NH2-mesoporous silica catalysts result in high conversion (>95%) and can easily be reused by washing with water. Furthermore, the catalytic performances of the asymmetric nickel-salen complex bound to mesoporous silicas were found to be greater than 60% which is comparable to the homogenous nickel complex catalyst (62% conversion) but are more easily recycled.
The further modification of catalysts to capture the remaining surface silanol groups in the modified-mesoporous silicas has been carried out by using chlorotrimethylsilane to obtain the surface functionalised with trimethyl groups instead of silanols. The methylated catalysts with MCM-41 and MCM-48 as support demonstrate better recyclability, while this was not observed in the cage-like SBA-1 and SBA-2 supports catalyst as the presence of additional trimethylsilyl groups could cause more pore blocking.

Type of Work:Ph.D. thesis.
Supervisor(s):Shannon, Ian
School/Faculty:Colleges (2008 onwards) > College of Engineering & Physical Sciences
Department:School of Chemistry
Subjects:QD Chemistry
Institution:University of Birmingham
ID Code:3738
This unpublished thesis/dissertation is copyright of the author and/or third parties. The intellectual property rights of the author or third parties in respect of this work are as defined by The Copyright Designs and Patents Act 1988 or as modified by any successor legislation. Any use made of information contained in this thesis/dissertation must be in accordance with that legislation and must be properly acknowledged. Further distribution or reproduction in any format is prohibited without the permission of the copyright holder.
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