Vitiello, Rosa (2015) Catalytic Processes in Biorefinery. [Tesi di dottorato]

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Abstract

The biorefinery is a system that uses as feedstocks biomasses and recover from these energy, fuel and chemicals. There are many processes considered in the biorefinery system, but in this thesis the biorefinery that uses as feedstock oil, in particular dedicated crops and waste vegetable oils were considered. In the first part of this thesis the biodiesel production process was studied. One possible route to produce biodiesel from waste oils (carachetrized by high concentrations of Free Fatty Acids, FFAs), is the use of a two steps process: an esterification reaction of FFAs with glycerol and a successive transesterification reaction with methanol of the whole mixture using a basic catalyst. In this thesis the esterification step of FFAs with glycerol, in presence of a new acid heterogeneous catalyst based on sulfonated polymers with enhanced temperature resistance, was studied. The use of this type of catalyst has the advantage of using a relatively high temperature favouring the reaction by stripping of water formed during the esterification The use of an acid catalyst that is able to tranesesterify the glycerides and to esterify the FFAs is onther way to obtained biodiesel from waste or non edible oils. In this thesis the reactions of contemporany esterification of FFAs and tranesterification of glycerides were studied using new homogeneous or supported homogneous Zn(II) catalysts and a NbO2/SiO2 heterogeneous catalyst. The second part of this thesis was devoted to study of new catalysts for chlorination reaction of glycerol recovered from biodiesel production process.The behavior of three series of homologous catalysts, chloroacetic acid series (acetic acid, monochloroacetic, dichloroacetic and trichloroacetic acid), glycolic acid series (glycolic acid, di‐glycolic acid and thio‐glycolic acid) and amminoacid series (glutamic acid, aspartic acid and cysteine), were investigated for their activity and selectivity to produce dichlorohydrins, important intermediates for epichlorohydrin production. In the present study we explored also a completely new class of catalysts for glycerol chlorination, represented by acyl chlorides, never reported in the literature. The catalysts studied are acetyl chloride, propanoyl chloride, adypoyl chloride, butandioil di-chloride, propandioil di-chloride and phenylacetyl chloride and more precisely it is reported a comparison between the acyl chlorides respect to corresponding carboxylic acid. The influence of some reaction parameters are studied as for example the effects of the pressure on activity and selectivity. Finally I use acyl chloride in stoichiometric amount in order to open new opportunities for chlorination process of glycerol with hydrochloric acid performed in situ.

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