The chemical industry of today is under increased pressure to develop novel green materials, bio-fuels as well as sustainable chemicals for the chemical industry. Indeed, the endeavour is to move towards more eco-friendly cost efficient production processes and technologies and chemical transformation of renewables has a central role considering the future sustainable supply of chemicals and energy needed for societies. In the Nordic countries, the importance of pulping and paper industry has been particularly pronounced and the declining European demand on these products as a result of our digitalizing world has forced the industry to look at alternative sources of revenue and profitability. In this thesis, the production of levulinic and formic acid from biomass and macromolecules has been studied. Further, the optimum reaction conditions as well as the influence of the catalyst and biomass type were also discussed.
Nordic sulphite and sulphate (Kraft) cellulose originating from two Nordic pulp mills were used as raw materials in the catalytic synthesis of green platform chemicals, levulinic and formic acids, respectively. The catalyst of choice used in this study was a macro-porous, cationic ion-exchange resin, Amberlyst 70, for which the optimal reaction conditions leading to best yields were determined. Cellulose from Nordic pulp mills were used as raw materials in the catalytic one-pot synthesis of ‘green’ levulinic and formic acid. The kinetic experiments were performed in a temperature range of 150–200 °C and an initial substrate concentration regime ranging from 0.7 to 6.0 wt %. It was concluded that the most important parameters in the one-pot hydrolysis of biomass were the reaction temperature, initial reactant concentration, acid type as well as the raw material applied. The reaction route includes dehydration of glucose to hydroxymethylfurfural as well as its further rehydration to formic and levulinic acids. The theoretical maximum yield can hardly be obtained due to formation of humins. For this system, maximum yields of 59 mol % and 68 mol % were obtained for formic and levulinic acid, respectively. The maximum yields were separately obtained in a straight-forward conversion system only containing cellulose, water and the heterogeneous catalyst. These yields were achieved at a reaction temperature of 180 °C and an initial cellulose intake of 0.7 wt % and belong to the upper range for solid catalysts so far presented in the literature.
The reaction network of the various chemical species involved was investigated and a simple mechanistic approach involving first order reaction kinetics was developed. The concept introduces a one-pot procedure providing a feasible route to green platform chemicals obtained via conversion of coniferous soft wood pulp to levulinic and formic acids, respectively. The model was able to describe the behaviour of the system in a satisfactory manner (degree of explanation 97.8 %). Since the solid catalyst proved to exhibit good mechanical strength under the experimental conditions applied here and a one-pot procedure providing a route to green platform chemicals was developed. A simplified reaction network of the various chemical species involved was investigated and a mechanistic approach involving first order reaction kinetics was developed.
In this paper, both sulphite and sulphate (Kraft) cellulose from Nordic pulp mills were used as raw materials in the catalytic one-pot synthesis of green platform chemicals, levulinic and formic acids, respectively. The catalyst of choice was a macro-porous, cationic ion-exchange resin, Amberlyst 70. The optimal reaction conditions were determined and the influence of various gas atmospheres was investigated. The maximum yields of 53% formic acid and 57% of levulinic acid were separately obtained in a straight-forward conversion system only containing cellulose, water and the heterogeneous catalyst. The concept introduces a one-pot procedure providing a feasible route to green platform chemicals obtained via conversion of coniferous soft wood pulp to levulinic and formic acids, respectively.
The production of levulinic acid from biomass and macromolecules has been reviewed. It was concluded that the most important parameters in the one-pot hydrolysis of biomass, also including dehydration of glucose to hydroxymethylfurfural as well as its further rehydration to formic and levulinic acids, respectively, are the reaction temperature, initial reactant concentration, acid type as well as the raw material applied. The theoretical maximum yield can hardly be obtained due to formation of humins. Further, the optimum reaction conditions as well as the influence of the catalyst and biomass type are also discussed.
Nordic sulphite and sulphate (Kraft) cellulose originating from Nordic pulp mills were used as raw materials in the catalytic synthesis of green platform chemicals, levulinic and formic acids, respectively. The catalyst of choice used in this study was a macro-porous, cationic ion-exchange resin Amberlyst 70 for which the optimal reaction conditions leading to best yields were determined. For this system, maximum yields of 53 mol-% and 57 mol-% were obtained for formic and levulinic acid, respectively. The reaction network of the various chemical species involved was investigated and a simple mechanistic approach involving first order reaction kinetics was developed. The prototype model was able to describe the behaviour of the system in a satisfactory manner.
In this paper, sulphite cellulose from a Swedish pulp mill was applied as the raw material upon catalytic, one-pot synthesis of green platform chemicals – levulinic and formic acids. Cationic ion-exchange resin, Amberlyst 70, was the catalyst of choice and the optimal reaction conditions leading to best yields were determined. The kinetic experiments were performed in a temperature range of 180–200 °C and an initial substrate concentration regime ranging from 0.7 to 6.0 wt %. For this system, maximum theoretical yields of around 59 mol % and 68 mol % were obtained for formic and levulinic acid, respectively. These yields were achieved at a reaction temperature of 180 °C and an initial cellulose intake of 0.7 wt %. A simplified reaction network of the various chemical species involved was investigated and a mechanistic approach involving first order reaction kinetics was developed. The model was able to describe the behaviour of the system in a satisfactory manner (degree of explanation 97.8 %). Since the solid catalyst proved to exhibit good mechanical strength under the experimental conditions applied here, the concept introduces a one-pot procedure providing a route to green platform chemicals from coniferous soft wood pulp to produce levulinic and formic acids, respectively.
Herein, one-pot conversion of cellulose to platform chemicals, formic and levulinic acids was demonstrated. The catalyst selected was an affordable, acidic ion-exchange resin, Amberlyst 70, whereas the cellulose used was sulfite cellulose delivered by a Swedish pulp mill. Furthermore, in an attempt to better understand the complex hydrolysis network of the polysaccharide, kinetic experiments were carried out to pinpoint the optimal reaction conditions with an initial substrate concentration of 0.7–6.0 wt% and a temperature range of 180–200 °C. Higher temperatures could not be used due to the limitations in the thermal stability of the catalyst. Overall, maximum theoretical yields of 59 and 68 mol% were obtained for formic and levulinic acid, respectively. The parameters allowing for the best performance were reaction temperature of 180 °C and initial cellulose concentration of 0.7 wt%. After studying the behavior of the system, a simplified reaction network in line with a mechanistic approach was developed and found to follow first order reaction kinetics. A satisfactory fit of the model to the experimental data was achieved (97.8 % degree of explanation). The catalyst chosen exhibited good mechanical strength under the experimental conditions and thus, a route providing green platform chemicals from soft wood pulp from coniferous trees (mixture of Scots Pine and Norway Spruce) was demonstrated.
A series of bimetallic catalysts Au–M (where M = Cu, Co and Ru) were supported on a reducible TiO2 oxide via deposition-precipitation (DP) method with a slow decomposition of urea as the precipitating agent. The characteristic structural features of the prepared materials were characterized by various physico-chemical techniques such as X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). XPS results indicated the formation of alloyed bimetallic particles on the TiO2 support. TEM results confirmed the fine dispersion of metal nanoparticles on the support with an average particle size in the range of 3–5 nm. An industrially important process, oxy-functionalization of α-pinene was carried out over the prepared bimetallic heterogeneous catalysts under liquid phase conditions. Reaction parameters such as the reaction time, temperature, and the effect of solvent were studied for optimal conversion of α-pinene into verbenone. The major products obtained were verbenone, verbenol, α-pinene oxide and alkyl-pinene peroxide. The activity of the catalysts followed the order; AuCu/TiO2 > AuCo/TiO2 > Cu/TiO2 > Au/TiO2 > AuRu/TiO2. Upon comparison of the various catalysts, AuCu/TiO2 was found to be an active and selective catalyst towards the formation of verbenone. The temperature, nature of the catalysts and the choice of solvents greatly influenced the reaction rate.