Un esempio di economia circolare: valorizzazione catalitica di biomasse a chemicals e biofuel (Butil Levulinato)

This work was conducted at the Department of Chemistry and Industrial Chemistry in Pisa. The aim of this work was the valorisation of lignocellulosic biomasses to obtain chemicals and fuels additives. The aim of the thesis was the valorisation of the cellulosic fraction of two pre-treated biomasses: E. nitens and P. Pinaster. Pre-treatments were previously used to remove the hemicellulosic and lignin fractions from the biomasses. The pre-treated biomasses were converted into chemicals such as glucose and levulinc acid by a hydrolysis reaction in presence of soluble acid catalysts. The residual cellulosic fractions of the pre-treated biomasses were valorised by the alcoholysis reaction using acid like catalyst in homogeneous system. The reaction was implemented and optimised using n-butanol as a solvent and sulphuric acid as a catalyst to obtain Butyl Levulinate. Model mixtures were prepared based on the characterisation of the products obtained from the reaction, by using commercial reactants. The mixtures were then used in blend with commercial Diesel for engine performance tests. The engine tests were carried out in collaboration with the Energy Engineering Department at the University of Pisa, at “Centro di Ricerca Interuniversitario sulle Biomasse da Energia” (CRIBE) in San Piero a Grado (Pisa). A comparative study about emissions and performances of the engine powered by commercial Diesel and the different prepared blends was carried out, based on the results obtained by the engine tests

Valorization of Papermill Wastes for the Production of Levulinic Acid and Butyl Levulinate

The waste management policy strongly encourages the valorization of waste biomas to give strategic biochemicals, instead of their traditional combustion for energy recovery or, even worse, of their landfill disposal. In this context, the acid-catalysed hydrothermal conversion of negative-value bio-wastes into levulinic acid (LA) and butyl levulinate (BL) represents a smart exploitation widely adaptable to different kinds of waste feedstocks. Now, particular attention was devoted to the cellulose-rich powder which derives from the cutting operations occurring during the tissue paper production and represents a waste for paper mill processes. LA is obtained by acid hydrolysis of biomass cellulose fraction and was classified as one of the top-12 promising building blocks. BL has been identified as important versatile biomolecules employed for the preparation of fuel additives, polymers and flavoring formulations. In this research, this cellulose-rich feedstock was used for the production of LA in water and BL in n-butanol, adopting in both cases a dilute acid and/or inorganic salts as catalysts. The effects of the main reaction parameters on the catalytic performances to the target products were investigated and optimized. The highest LA mass yield was obtained in the presence of very diluted HCl at 180 °C, corresponding to about 45 wt%. On the other hand, under the best reaction conditions, working in n-butanol, at 190°C in the presence of diluted H2SO4, BL yield over 40 mol% respect to glucan content was reached

A green approach for the valorization of Arundo donax L. and paper mill waste to produce the advanced biofuel n-butyl levulinate

Today, the continue depletion of fossil sources represents one of the main problems and European Union has incremented the amount of renewable fraction inside automotive fuels obtained from lignocellulosic biomasses. In this work, the production of the advanced biofuel n-butyl levulinate (BL) from Arundo donax L. and industrial paper waste powder has been investigated. In particular, the direct acid-catalysed alcoholysis employing n-butanol as solvent/reagent and H2SO4 as homogeneous catalyst in the presence of microwave and traditional heatings has been optimized. With both the investigated biomasses, BL yields around 30 mol% have been achieved with high loadings of feedstock, 20 and 14 wt% for Arundo donax L. and paper waste powder, respectively, at 190 °C after 15 min, adopting microwave heating and H2SO4 loading of 1.2 wt%. Moreover, the employment of traditional heating has allowed us to achieve BL yields about 30 mol% with the low catalyst loadings of 0.6 and 0.4 wt% for Arundo donax L. and paper waste powder, respectively, at 200°C after 3h, adopting the same biomass loadings (20 and 14 wt%). Finally, a preliminary study of diesel engine performances and emissions regarding the potential application of the obtained mixture as additive for diesel fuel was successfully performed

A green approach for the valorisation of Arundo donax L. and paper mill waste to produce the advanced biofuel n-Butyl Levulinate

The continue depletion of fossil sources and their environmental impact represent one of the main problems of this century. Therefore, a lot of studies have been recently performed in order to produce sustainable advanced biofuels. These components are directly obtained from not edible lignocellulosic biomasses and can totally or partially replace fossil fuel. In this work, the feasible production of the advanced biofuel n-Butyl Levulinate (BL) from an herbaceous lignocellulosic biomass and an industrial paper mill waste has been investigated and optimized. Alkyl levulinates can be produced from cellulosic fraction of biomasses. Up to now, several studies have been focused on the possible production of these compounds through a two-step process: a preliminary acid hydrolysis of the biomass to levulinic acid, followed by the purification of levulinic acid and its esterification to the target molecule. This strategy is obviously limited by the high cost connected with the overall process. By contrast, the one-pot alcoholysis of raw biomasses directly to the target product represents an innovative easier and cheaper approach. Starting form two different kinds of raw biomasses (Arundo donax L. and industrial paper mill waste), the direct acid-catalysed alcoholysis to n-butyl levulinate has been studied, employing n-butanol as solvent and H2SO4 as homogeneous catalyst (0.6-1.2 wt%). With both the considered biomasses, BL yields around 35 mol% have been achieved with high loading of feedstock between 14 and 20 wt%. Furthermore, the feasibility of our process has been tested, employing both microwave and traditional heating system, reaching the BL molar yield of 38 mol% with the high biomass loading of 20 wt% starting from A. donax L. Finally, the BL yield of 33 mol% was achieved with the extremely low catalyst loading of 0.6 wt% working with biomass loading up to 20 wt% of A. donax L., at 200°C for 180 minutes employing traditional heating. This obtained result is very promising because the employed reaction parameters, in particular the very low acid concentration, make our process promising and feasible especially from an industrial point of view

Copertina della rivista Catalysts, volume 10, issue 5, Maggio 2020. Biomass Alcoholysis to n-Butyl Levulinate: a Valuable Diesel Blender

Biomass Alcoholysis to n-Butyl Levulinate: a Valuable Diesel Blende

Complete Exploitation of Eucalyptus nitens: optimization of hydrothermal conversion of its cellulose fraction to levulinic acid and butyl levulinate

The purpose of the present work is the complete sustainable exploitation of Eucalyptus nitens biomass in the perspective of a circular economy. In this work, Eucalyptus nitens ADW (autohydrolysed-delignified sample) wood, obtained from a first autohydrolysis treatment of the starting biomass to remove and exploit hemicellulose and water-soluble extractives, followed by a second step of delignification on the resulting solid through the HCl-catalyzed acetic acid Acetosolv method, was employed. This cellulose-rich feedstock was used for the production of levulinic acid in water and butyl levulinate in n-butanol, in both cases by reaction in diluted acid medium, investigating and optimizing the main reaction parameters, e.g. temperature, reaction time and acid concentration

One-pot alcoholysis of the lignocellulosic eucalyptus nitens biomass to n-butyl levulinate, a valuable additive for diesel motor fuel

The present investigation represents a concrete example of complete valorization of Eucalyptus nitens biomass, in the framework of the circular economy. Autohydrolyzed-delignified Eucalyptus nitens was employed as a cheap cellulose-rich feedstock in the direct alcoholysis to n-butyl levulinate, adopting n-butanol as green reagent/reaction medium, very dilute sulfuric acid as a homogeneous catalyst, and different heating systems. The effect of the main reaction parameters to give n-butyl levulinate was investigated to check the feasibility of this reaction and identify the coarse ranges of the main operating variables of greater relevance. High n-butyl levulinate molar yields (35–40 mol%) were achieved under microwave and traditional heating, even using a very high biomass loading (20 wt%), an eligible aspect from the perspective of the high gravity approach. The possibility of reprocessing the reaction mixture deriving from the optimized experiment by the addition of fresh biomass was evaluated, achieving the maximum n-butyl levulinate concentration of about 85 g/L after only one microwave reprocessing of the mother liquor, the highest value hitherto reported starting from real biomass. The alcoholysis reaction was further optimized by Response Surface Methodology, setting a Face-Centered Central Composite Design, which was experimentally validated at the optimal operating conditions for the n-butyl levulinate production. Finally, a preliminary study of diesel engine performances and emissions for a model mixture with analogous composition to that produced from the butanolysis reaction was performed, confirming its potential application as an additive for diesel fuel, without separation of each component.Ministerio de Economía y Competitividad | Ref. CTQ2017-82962-RXunta de Galicia | Ref. ED481A-2017/316Ministero dell'Università e della Ricerca | Ref. VISION PRIN 2017 FWC3WC_00