Carbon-carbon bond forming reactions for bio-oil upgrading: heterogeneous catalyst and model compound studies

Development of a renewable liquid transportation fuel is likely to be one of the most important challenges faced by scientists during the 21st century. As biomass provides a renewable source of carbon it is ideally situated to supply this alternative to the traditional petroleum derived feedstocks. While there have been a number of different techniques used to convert biomass to liquid fuels, fast pyrolysis is particularly promising as it can quite efficiently break down biomass directly into a liquid. This resulting liquid, called bio-oil, is a very complex mixture containing a large number of oxygen functionalized compounds. Unfortunately, this oil has a number of issues that must be resolved before it can be effectively utilized as a liquid transportation fuel including acidity, reactivity, and low energy density. With this in mind, heterogeneously catalyzed C-C bond forming reactions potentially valuable for the upgrading of bio-oil were investigated. The aldol condensation is a well known reaction in organic chemistry usually promoted through the use of strong acid or bases. However, uses of these types of catalysts will likely cause undesirable side reactions. Ideally cooperative catalysis allows for weaker acids and bases to work in tandem to promote the reaction. Use of aluminum phosphate catalysts allowed for the tuning of the acidity and basicity of the materials through a nitridation process and hence probing of this cooperative catalysis. Through performing aldol condensations using model bio-oil compounds acetaldehyde, acetone, and MEK, it was found that acid and base sites were both needed to efficiently promote the cross condensation of the aldehyde and ketone. After reaction testing, a mechanism was proposed demonstrating the benefits of using heterogeneous catalysts as it allows for the coexistence of both acid and base sites. Ketonization of carboxylic acids is also an ideal reaction for bio-oil upgrading as it removes acidity and oxygen as well as creates C-C bonds. However, this reaction is almost always performed in the vapor phase due to the high temperatures necessary to achieve significant conversions. In order to try to engineer a more active catalyst able to perform the reaction at lower temperatures, more must be understood about ketonization. Condensed phase ketonization was examined using ceria catalysts calcined at different temperatures. It was found that the reaction proceeded either through the formation of carboxylates in the bulk or on the surface of the catalyst depending on the temperature of calcination. Moreover, through in-situ XRD, this trend was found to be true in the vapor phase as well. Kinetic studies found that the mechanism for both these routes was likely the same. As ketonization had been claimed to be sensitive to the surface structure of the ceria catalyst, shape selective ceria nanocrystals were synthesized and examined in acetic acid ketonization both in the vapor and condensed phases. It was found that in the condensed phase the catalysts underwent carboxylate formation in the bulk thus changing the crystal structure of the materials. However, in the vapor phase this did not occur but a clear trend with surface structure was not determined. Thus it is likely the surface structure of the ceria catalysts isn\u27t of large influence in realistic ketonization conditions. Reaction condition influences were probed as well. It was found that the temperature of ketonization greatly influenced the reaction pathway with intermediate temperature reactions resulting in metal carboxylate formation in the bulk and high temperatures promoting the reaction on the surface. Discussion of these temperature regimes and a more detailed proposed mechanism are delivered. Lastly, ketonization using mixed metal oxides was studied. It was found that mixing of ceria with another oxide greatly changed the catalyst properties. Coupled with reaction testing, experiments determined that metal carboxylate formation and decomposition are of supreme importance for ketonization and are influenced by mixing of oxides. Along with the work using pure ceria catalysts, this research into ketonization is a significant step forward into understanding of the reaction and how it can be applied to the upgrading of fast pyrolysis bio-oil

A forest of masts: the image of the River Thames in the long eighteenth century

The visual image of the River Thames was central to the identity of London in the long eighteenth century. Art historical engagement with the subject has been dominated by refined upriver views, especially depictions of sites of royal residence and scenes of pageantry. This focus eclipses a significant untapped body of contemporary Thames imagery which suggests the existence of a more complex relationship between the visualisation of London’s river and the larger social, ideological and economic contexts of Britain’s rapidly developing global maritime and imperial power. This thesis proposes that only by reconnecting these works with the more familiar visual culture of eighteenth-century maritime London, can the full extent to which the river was identified as a signifier of national and imperial consciousness be fully understood. This identification is most apparent in depictions of the commercial and naval activity in the mercantile environs of the port to the east of London Bridge which effectively constitute a visual concordia discors with aggrandised upriver subjects. Thames imagery is also prevalent in the genre of satire where the countercultural nature of the port, characterised via its stereotypical portrayal of a bawdy labour force, undermines the polite pretensions of high art. In topographical views of the capital the dramatic physical rationalisation of the Thames in terms of new bridges and docks was harnessed to raise the profile of London and its river to that of an efficient cosmopolitan port suited for commercial empire. Above all, the image of the Thames evolved into a powerful and widely understood symbol reflecting a patriotic national identity constructed around maritime trade and naval power. This thesis argues for an alternative, more complex image of the Thames in the long eighteenth century which is informed by a range of ideological issues centred around the meaning of commerce and empire from a period when the river became the emblem of London’s increasing self-identification as the centre of a maritime nation of unprecedented scale

Close focus : interpreting Western Australia’s visual culture

Distance from the centres of world art and from national hubs of creative practice provides both opportunities and constraints for Western Australian visual artists. Informed but isolated, they have learned to direct the lens shaped by received ideas onto the extraordinary natural environment they inhabit. Regional perspectives influence this act of re-focusing, which is inflected by local knowledge and personal experience in a process of reinvention and re-imagination that has escalated since the Second World War.The objective of this PhD by supplication is to situate my practice as an art historian, critic and curator within the broader context of Australian visual culture and to examine how the process of assimilation, described by George Seddon as taking 'imaginative possession', has contributed to our understanding of local identity within the wider framework of a national identity.In my writing and through my activity as a curator of exhibitions over the past two decades, I have identified the importance of local conditions in generating a critical, regional practice and I have shown how imported ideas have been absorbed, modified and accommodated within the work of the State’s leading artists to create a vibrant sense of regional identity that makes a significant contribution to our understanding of a wider and more comprehensive view of cultural practice in Australia

U.S TOBACCO GROWER ISSUES

Crop Production/Industries,

A Quality System Database

A quality system database (QSD), and software to administer the database, were developed to support recording of administrative nonconformance activities that involve requirements for documentation of corrective and/or preventive actions, which can include ISO 9000 internal quality audits and customer complaints