The search for sustainable energy resources is one of this century’s great challenges. Biofuels (fuels produced from biomass) have emerged as one of the most promising renewable energy sources, offering the world a so­lution to its fossil-fuel addiction. They are sustainable, biodegradable, and contain fewer environmental contaminants than fossil fuels.

One of the biggest difficulties with biofuel production, however, is grabbing carbon for fuel while also removing oxygen from biomass. Un­like fossil fuel sources, biomass is rich in oxygen, which makes its trans­formation into fuel challenging. Catalysis offers a cheap, efficient, and sustainable way to remove oxygen from biomass, increasing its potential usefulness to the world’s energy needs.

Heterogeneous catalysis has a long history of facilitating energy-effi­cient selective molecular transformations. It already contributes to most chemical manufacturing processes and to many industrial products. Ca­talysis also plays a central role in overcoming the barriers to economical and sustainable biofuel production.

Technical advances in catalyst design and processes are even more es­sential for second-generation biofuels produced from non-food feedstocks. As much oxygen as possible must be removed to gain the maximum ener­gy density. In addition, the costs of oxygen removal need to be minimized.

Research that identifies inexpensive and efficient catalysts is crucial to the world’s energy needs. Additionally, we need catalysts and catalytic processes that minimize hydrogen consumption, increase overall process activity, and gain high fuel yields. The research gathered in this compen­dium contributes to this vital field of investigation.

Juan Carlos Serrano-Ruiz, PhD

Concerns over the economics of proven fossil fuel reserves, in concert with government and public acceptance of the anthropogenic origin of ris­ing CO2 emissions and associated climate change from such combustible carbon, are driving academic and commercial research into new sustain­able routes to fuel and chemicals. The quest for such sustainable resources to meet the demands of a rapidly rising global population represents one of this century’s grand challenges. In Chapter 1, Lee discusses catalytic solutions to the clean synthesis of biodiesel, the most readily implemented and low cost, alternative source of transportation fuels, and oxygenated organic molecules for the manufacture of fine and speciality chemicals to meet future societal demands.

Chapter 2, by Bezergianni, argues that catalytic hydrotreatment of liq­uid biomass is a technology with the potential to overcome the limitations of biomass fuel productions. The author points to a wide range of new alternative fuels that are being developed using this technology, arguing that they are more useful than those developed using older methods, and points to catalytic hydrotreatment as the future of biofuels.

Chapter 3, by Murzin and Holmbom, describes some of the contem­porary methods for the chemical analysis of biomass-derived chemicals. All available methods could not have been treated in this review, therefore the focus was mainly on chromatographic methods. A more comprehen­sive overview of analytical methods was published several years ago by one of the authors [31,33]. In the current work, detailed procedures were discussed for only a few cases as the emphasis was laid more on general approaches.

Concerns about diminishing fossil fuel reserves along with global warming effects caused by increasing levels of CO2 in the atmosphere are driving society toward the search for new renewable sources of energy that can substitute for coal, natural gas and petroleum in the current energy system. Lignocellulosic biomass is abundant, and it has the potential to significantly displace petroleum in the production of fuels for the trans­portation sector. Ethanol, the main biomass-derived fuel used today, has benefited from production by a well-established technology and by partial compatibility with the current transportation infrastructure, leading to the domination of the world biofuel market. However, ethanol suffers from important limitations as a fuel (e. g., low energy density, high solubility in water) than can be overcome by designing strategies to convert non-edible lignocellulosic biomass into liquid hydrocarbon fuels (LHF) chemically similar to those currently used in internal combustion engines. Chapter 4, by Serrano-Ruiz and Dumesic, describes the main routes available to carry out such deep chemical transformation (e. g., gasification, pyroly­sis, and aqueous-phase catalytic processing), with particular emphasis on those pathways involving aqueous-phase catalytic reactions. These latter catalytic routes achieve the required transformations in biomass-derived molecules with controlled chemistry and high yields, but require pretreat — ment/hydrolysis steps to overcome the recalcitrance of lignocellulose. To be economically viable, these aqueous-phase routes should be carried out with a small number of reactors and with minimum utilization of external fossil fuel-based hydrogen sources, as illustrated in the examples present­ed here.

Catalytic refining of bio-oil by reacting with olefin/alcohol over solid acids can convert bio-oil to oxygen-containing fuels. In Chapter 5, Zhang and colleagues studied the reactivities of groups of compounds typically present in bio-oil with 1-octene (or 1-butanol) at 120 °C/3 h over Dowex50WX2, Amberlyst15, Amberlyst36, silica sulfuric acid (SSA) and Cs25H05PW12O40 supported on K10 clay (Cs25/K10, 30 wt. %). These compounds include phe­nol, water, acetic acid, acetaldehyde, hydroxyacetone, D-glucose and 2-hy — droxymethylfuran. Mechanisms for the overall conversions were proposed. Other olefins (1,7-octadiene, cyclohexene, and 2,4,4- trimethylpentene) and alcohols (iso-butanol) with different activities were also investigated. All the olefins and alcohols used were effective but produced varying product selectivities. A complex model bio-oil, synthesized by mixing all the above­stated model compounds, was refined under similar conditions to test the catalyst’s activity. SSA shows the highest hydrothermal stability. Cs25/K10 lost most of its activity. A global reaction pathway is outlined. Simultane­ous and competing esterification, etherfication, acetal formation, hydration, isomerization and other equilibria were involved. Synergistic interactions among reactants and products were determined. Acid-catalyzed olefin hy­dration removed water and drove the esterification and acetal formation equilibria toward ester and acetal products.

A newly designed downdraft wood stove achieved low-emission heat­ing by integrating an alumina-supported mixed metal oxide catalyst in the combustion chamber operated under high temperature conditions. In the first step in Chapter 6, by Bindig and colleagues, a catalyst screening has been carried out with a lab-scale plug flow reactor in order to iden­tify the potentially active mixed metal oxide catalysts. Mixed metal ox­ide catalysts have been the center of attention because of their expected high temperature stability and activity. The catalyst has been synthesized through two novel routes, and it has been integrated into a downdraft wood stove. The alumina-supported mixed metal oxide catalyst reduced the volatile hydrocarbons, carbon monoxide and carbonaceous aerosols by more than 60%.

As part of a programme aimed at exploiting lignin as a chemical feed­stock for less oxygenated fine chemicals, several catalytic C-C bond form­ing reactions utilising guaiacol imidazole sulfonate are demonstrated in Chapter 7, by Leckie and colleagues. These include the cross-coupling of a Grignard, a non-toxic cyanide source, a benzoxazole, and nitromethane. A modified Meyers reaction is used to accomplish a second constructive deoxygenation on a benzoxazole functionalised anisole.

5-Halomethylfurfurals can be considered as platform chemicals of high reactivity making them useful for the preparation of a variety of im­portant compounds. In Chapter 8, by Gao and colleagues, a one-pot route for the conversion of carbohydrates into 5-chloromethylfurfural (CMF) in a simple and efficient (HCl-H3PO4/CHCl3) biphasic system has been in­vestigated. Monosaccharides such as D-fructose, D-glucose and sorbose, disaccharides such as sucrose and cellobiose and polysaccharides such as cellulose were successfully converted into CMF in satisfactory yields under mild conditions. Our data shows that when using D-fructose the optimum yield of CMF was about 47%. This understanding allowed us to extent our work to biomaterials, such as wood powder and wood pulps with yields of CMF obtained being comparable to those seen with some of the enumerated mono and disaccharides. Overall, the proposed (HCl — H3PO4/CHCl3) optimized biphasic system provides a simple, mild, and cost-effective means to prepare CMF from renewable resources.

Chapter 9, by de Canck and colleagues, describes how a Periodic Mes- oporous Organosilica (PMO) functionalized with sulfonic acid groups has been successfully synthesized via a sequence of post-synthetic modifica­tion steps of a trans-ethenylene bridged PMO material. The double bond is functionalized via a bromination and subsequent substitution obtaining a thiol functionality. This is followed by an oxidation towards a sulfonic acid group. After full characterization, the solid acid catalyst is used in the acetylation of glycerol. The catalytic reactivity and reusability of the sulfonic acid modified PMO material is investigated. The catalyst showed a catalytic activity and kinetics that are comparable with the commercially available resin, Amberlyst-15, and furthermore the catalyst can be recy­cled for several subsequent catalytic runs and retains its catalytic activity.

Chapter 10, by Ramirez-Morenoe et al., offers an alternative method to reduce CO2 emissions through the use of alkaline and/or alkaline-earth oxide ceramics. These are able to selectively trap CO2 under different con­ditions and suggests the feasibility of these kinds of solid for being used with different capture technologies and processes, such as: pressure swing adsorption (PSA), vacuum swing adsorption (VSP), temperature swing adsorption (TSA) and water gas shift reaction (WGSR). Therefore, the fundamental study regarding this matter can help to elucidate the whole phenomena in order to enhance the sorbents’ properties.