Methoxycarbonylation of alkenes with biomass-derived CO

Abstract

The production of chemicals, fuels and energy from renewable feedstock, such as biomass, has seen increasing interest in the last decade. One of the key issues regarding biorenewables is the reduction of the oxygenation grade in molecules, the removal of oxygen. This thesis focuses on the removal of oxygen, in the form of carbon monoxide, and use in a tandem reaction for the methoxycarbonylation of alkenes. Furthermore, the production of γ-valerolactone (GVL), a promising green fuel has been exploited.Chapter 1: Introduction provides a walk-through of subjects like biomass and its utility, dehydration of sugars, the importance of the furanoic platform and carbonylation reactions. All these arguments are described in detail, taking into account the current and past research, accurately chosen in order to offer an insight for next chapters.Chapter 2: Experimental, deals with the analytical techniques and the catalytic setups of the reactions. Chapter 3: Results and Discussion, is divided into two main parts. The first one reports and discuss the data obtained after the methoxycarbonylation reaction of 5 HMF (5-hydroxymethyl furfural), to yield methyl heptanoate (MH), methyl levulinate (ML), and GVL,the three products we investigated. The catalytic system is optimized, following the indication given by the results of the reactions. All the steps of the process are deeply discussed in this section. Consideration on the reaction time, on the choice and the quantity of the acidic catalyst, the nature and the amount of the palladium precursor and the phosphine ligand, a screening of the reaction temperatures, and an investigation regarding different substrates (with a furanic backbone), alkenes and alcohols have been done. Our catalytic system proved to be valid to give good yields in a one-pot reaction from HMF to valuable products. All the data are gathered after GC-FID, GS-MS and HPLC analysis, run using naphthalene as internal standard. The second part examines the methoxycarbonylation reaction applied to different carbohydrates. Insights on the kinetics of the reaction and the reactivity of various carbohydrates can be inferred from the analysis of the reported data. Through thisscreening, our catalytic system proved to be active on a broad range sugars, from monosaccharides to polysaccharides, such as inulin and starch. Chapter 4: Conclusions, it summarizes the results, future perspectives and possible developments.