Biomass-derived oils, catalytic

Sharma, R.K., and Bakhshi, N.N. Catalytic Upgrading of Biomass-derived Oils to Transportation Fuels and Chemicals. Can. J. Chem. Eng. 69, 1991. 

Baker, E.G. Elliott, D.C. "Catalytic hydrotreating of biomass-derived oils." In This Volume. 

BAKER ELLIOTT Catalytic Hydrotreating of Biomass-Derived Oils... 

A variety of biomass-derived oils have been upgraded by catalytic hydrotreating in a 1-liter reactor system. Specific conclusions from our studies are as follows ... 

Sharma, R., Bakhshi, N., 1991. Catalytic upgrading of biomass-derived oils to transportation fuels and chemicals. The Canadian Journal of Chemical Engineering 69 (5), 1071—1081. 

As discussed in this book (Chapter 2, for example) a main difference between fossil fuels and biomass as feedstocks is that in the former case the functionalization of base chemicals obtained from the oil (ethylene, propylene, aromatics, etc.) occurs essentially by introduction of heteroatoms, while in the case of biomass-derived based chemicals (glycerol, for example) it is necessary to eliminate heteroatoms (oxygen, in particular). Consequently, the catalysts required to develop a petrochemistry based on bio-derived raw materials need to be discovered and cannot simply be translated from existing ones, even if the knowledge accumulated over many years will make this discovery process much faster than that involved in developing the petrochemical catalytic routes. 

Renewable raw materials can contribute to the sustainability of chemical products in two ways (i) by developing greener, biomass-derived products which replace existing oil-based products, e.g. a biodegradable plastic, and (ii) greener processes for the manufacture of existing chemicals from biomass instead of from fossil feedstocks. These conversion processes should, of course, be catalytic in order to maximize atom efficiencies and minimize waste (E factors) but they could be chemo- or biocatalytic, e.g. fermentation [3-5]. Even the chemocatalysts themselves can be derived from biomass, e.g. expanded com starches modified with surface S03H or amine moieties can be used as recyclable solid acid or base catalysts, respectively [6]. 

It has been shown that synthetic zeolites such as ZSM-5 can be used to convert oxygenated compounds derived from biomass materials into hydrocarbons which can be used as fuels or chemicals feedstocks (1,2,3,4). However, the pyrolysis oils obtained from biomass materials by different thermal and thermochemical processes (5,6) showed poor hydrocarbon yields and high tar content when contacted over ZSM-5 zeolite catalysts at high temperatures (7,8). Since the pyrolysis oils are composed of a wide variety of oxygenated compounds such as cyclopentanone, cyclopentenone, furfural, phenol, carbohydrate and carboxylic acid derivatives (9,10) it is difficult to point out exactly which family of compounds is contributing more to the observed tar and to the rapid deactivation of the catalysts. Catalytic studies on model compounds which are usually found in the biomass pyrolysis oils are therefore primordial in order to determine the best catalytic system for the up-grading of pyrolysis oils to useful hydrocarbon products. The reactions of some phenolic, carbonyl and carboxylic acid derivatives over ZSM-5 catalysts are already... 

Another important goal of green chemistry is the utilisation of renewable raw materials, i.e. derived from biomass, rather than crude oil. Here again, the processes used for the conversion of renewable feedstocks - mainly carbohydrates but also triglycerides and terpenes - should produce minimal waste, i.e. they should preferably be catalytic. 

---