Catalysis for chemicals production from bio-based building blocks: examples of industrial relevance

The research work presented in this PhD thesis is focused on two research topics which aim is to enhance the sustainability of the modern biorefinery. In fact, the production of an advanced biofuel such as 1-butanol is studied in the first part, while the second part deals with the valorisation of glycerol, which is a biodiesel co-product. Therefore, in the first part of the thesis 1-butanol production by means of the Guerbet reaction is studied. The catalytic synthesis of 1-butanol is more desirable than ABE fermentation because it allows to reach higher productivity, lowering the separation costs. The study is aimed to provide a deeper understanding on the effect of acid and base active sites. Therefore, pure basic alkaline earth metal oxides were synthesized and fully characterized. Afterwards, the oxide which showed the best performance was doped with H3PO4 and its catalytic behaviour was studied. Finally, its performance was compared with that one of hydroxyapatite, even with respect to its lifetime. Dihydroxyacetone, a glycerol derivative, upgrading into lactic acid is the topic of the second part of this work. Glycerol valorisation into chemicals might help to support the economic sustainability of biodiesel production. In fact, its disposal as a waste is expensive and not sustainable according to the biorefinery concept. Therefore, a continuous process aimed at directly upgrading glycerol is highly desirable. The main problem in dihydroxyacetone conversion is the need for water-resistant catalysts. A continuous process is more convenient from both an economical and a technological point of view than a batch one. In this thesis, a thorough study of metal phosphate-based catalysts reactivity in the aqueous phase and in a continuous-feed reactor is presented. The catalysts were fully characterized in order to understand the relationship between their physico-chemical characteristics and catalytic performance.