Maija L. Honkela

Influence of polar components in the dimerization of isobutene

Isooctane is seen as a potential replacement for methyl tert-butyl ether (MTBE) in gasoline. Isooctane can be produced via the indirect alkylation route in two steps. Isobutene is first dimerized to isooctenes, which are then further hydrogenated to isooctane. In the dimerization a polar component is used to enhance the selectivity for diisobutenes. In this study the effects of tert-butyl alcohol (TBA), methanol and MTBE in the dimerization reaction were compared on the basis of experimental results. All the oxygenates studied induced similar effects: higher selectivity for diisobutenes and lower isobutene conversion as the oxygenate content increased and temperature decreased. The different polarity of the components causes the need for more methanol or MTBE than TBA to get the same conversion and selectivity.

Chapter 11:Hydrotreating for Bio-Oil Upgrading

Bio-oils are produced from various biomass sources through processes such as pyrolysis and hydrothermal treatment. While conventional oils from fossil energy sources contain less than 0.1 wt% oxygen, the oxygen content of bio-oils can reach as high as 50 wt% causing several undesired properties such as high viscosity, instability and low energy content. The oxygen can be removed partly or totally by hydrodeoxygenation (HDO). Process characteristics of the HDO of wood-based bio-oils and HDO studies carried out with bio-oil model components are presented.