Production of ethyl lactate by activated carbon-supported Sn and Zn oxide catalysts utilizing lignocellulosic side streams

Abstract In this study, activated carbon-supported Sn and Zn oxide catalysts were prepared from hydrolysis lignin and used for the conversion of model solutions of trioses, hexoses, and lignocellulosic biomass hydrolysates to ethyl lactate. Both catalysts, SnO2@AC and ZnO@AC, were able to produce ethyl lactate in high yields. SnO2@AC was a more active and selective catalyst in triose (dihydroxyacetone) conversion, providing 99% yield to ethyl lactate. ZnO@AC, by contrast, was more selective in glucose and hydrolysate conversion, with a yield of 60% and 85%, respectively. The ethyl lactate yields were significantly higher than those from the optimized model solution experiments when using Zn…

The Effect of Mechanocatalytic Pretreatment on the Structure and Depolymerization of Willow

In this study, the effect of a mechanocatalytic pretreatment on the structure of willow and sugar release from pretreated willow was explored. In the mechanocatalytic approach, the pretreatment consists of solvent-free impregnation with sulfuric acid and a mechanical treatment with ball milling. Willow sawdust and pretreated samples were analyzed with field emission scanning electron microscope and X-ray diffraction. The products in the sugar solution were determined as the total reducing sugars with the 3,5-dinitrosalicylic acid method and monosaccharides with capillary electrophoresis. According to the results, milling increased the sugar production, depending on the sulfuric acid load. T…

Lignin-based activated carbon-supported metal oxide catalysts in lactic acid production from glucose

Abstract In this study, heterogeneous biomass-based activated carbon-supported metal oxide catalysts were prepared and tested for lactic acid production from glucose in aqueous solution. Activated carbons were produced from hydrolysis lignin by chemical (ZnCl2) or steam activation and modified with a nitric acid treatment and Sn, Al, and Cr chlorides to obtain carbon-based metal oxide catalysts. The modification of the carbon support by nitric acid treatment together with Sn and Al oxides led to an increase in lactic acid yield. The highest lactic acid yield (42 %) was obtained after 20 min at 180 °C with the Sn/Al (5/2.5 wt.%) catalyst on steam-activated carbon treated by nitric acid. Reus…

Arkipäiväisistä katseilta suojatuiksi : Nilsiän emäseurakunnan alueen kirkonkellot

Acid-catalyzed mechanocatalytic pretreatment to improve sugar release from birch sawdust : Structural and chemical aspects

This study examined acid-catalyzed mechanocatalytic pretreatment of birch sawdust without a separate impregnation step. Catalyst amount and pretreatment time were the key variables. Pretreated material was mixed with water for hydrolysis (100 °C, 60 min). The efficient release of total reducing sugars from birch sawdust is significant to the path towards biofuels and biochemicals. Based on the results, the structure and surface of birch sawdust changed as a function of mechanocatalytic pretreatment. Milling time caused significant transformations in birch structure and also increased the yields of reducing sugars. The highest yield of total reducing sugar from pretreated sawdust was 23.0% a…

Catalytic conversion of glucose to 5-hydroxymethylfurfural over biomass-based activated carbon catalyst

Selective and efficient dehydration of glucose to 5-hydroxymethylfurfural (HMF) has been widely explored research problem recently, especially from the perspective of more sustainable heterogeneous catalysts. In this study, activated carbon was first produced from a lignocellulosic waste material, birch sawdust. Novel heterogeneous catalysts were then prepared from activated carbon by adding Lewis or Brønsted acid sites on the carbon surface. Prepared catalysts were used to convert glucose to HMF in biphasic water:THF system at 160 °C. The highest HMF yield and selectivity, 51% and 78%, respectively, were obtained in 8 h with a catalytic mixture containing both Lewis and Brønsted acid sites…

Acid-catalyzed mechanocatalytic pretreatment to improve sugar release from birch sawdust: Structural and chemical aspects

Abstract This study examined acid-catalyzed mechanocatalytic pretreatment of birch sawdust without a separate impregnation step. Catalyst amount and pretreatment time were the key variables. Pretreated material was mixed with water for hydrolysis (100 °C, 60 min). The efficient release of total reducing sugars from birch sawdust is significant to the path towards biofuels and biochemicals. Based on the results, the structure and surface of birch sawdust changed as a function of mechanocatalytic pretreatment. Milling time caused significant transformations in birch structure and also increased the yields of reducing sugars. The highest yield of total reducing sugar from pretreated sawdust wa…

Brønsted and Lewis acid catalyzed conversion of pulp industry waste biomass to levulinic acid

Enormous amounts of fiber sludge are generated annually by the pulp industry as a by-product. As a cellulose-rich material, its current usage, mainly as fuel, is inefficient from a material efficiency point of view. This work studied the utilization of fiber sludge from a Finnish and a Swedish pulp mill as a potential feedstock to produce levulinic acid, a valuable platform chemical. The conversion experiments of fiber sludge to levulinic acid were performed in a microwave reactor with a mixture of H2SO4 and Lewis acid as the catalyst. The reaction conditions, which included reaction time and temperature as well as the H2SO4 and Lewis acid concentrations, were studied in detail. The highest…

Simultaneous production of furfural and levulinic acid from pine sawdust via acid-catalysed mechanical depolymerization and microwave irradiation

Abstract In this work pine sawdust was converted into levulinic acid (LA) and furfural. Sawdust was first pre-treated with sulfuric acid-catalysed mechanical depolymerization. The conversion reactions were then performed with microwave heating at 180 °C. To enhance the furfural yield and the efficient separation of furfural and LA, a biphasic water-toluene reaction system was used. The effect of an additional catalyst, AlCl3, on the yield of LA and furfural was also studied. According to the results the pre-treatment method enhanced the yields of LA. In addition, due to the microwave heating the reaction times were short. Additional AlCl3 catalyst enhanced the LA yield, however excellent fu…

Simultaneous production of furfural and levulinic acid from pine sawdust via acid-catalysed mechanical depolymerization and microwave irradiation

In this work pine sawdust was converted into levulinic acid (LA) and furfural. Sawdust was first pre-treated with sulfuric acid-catalysed mechanical depolymerization. The conversion reactions were then performed with microwave heating at 180 °C. To enhance the furfural yield and the efficient separation of furfural and LA, a biphasic water-toluene reaction system was used. The effect of an additional catalyst, AlCl3, on the yield of LA and furfural was also studied. According to the results the pre-treatment method enhanced the yields of LA. In addition, due to the microwave heating the reaction times were short. Additional AlCl3 catalyst enhanced the LA yield, however excellent furfural yi…

Conversion of Xylose to Furfural over Lignin-Based Activated Carbon-Supported Iron Catalysts

In this study, conversion of xylose to furfural was studied using lignin-based activated carbon-supported iron catalysts. First, three activated carbon supports were prepared from hydrolysis lignin with different activation methods. The supports were modified with different metal precursors and metal concentrations into five iron catalysts. The prepared catalysts were studied in furfural production from xylose using different reaction temperatures and times. The best results were achieved with a 4 wt% iron-containing catalyst, 5Fe-ACs, which produced a 57% furfural yield, 92% xylose conversion and 65% reaction selectivity at 170 &deg

Catalytic conversion of glucose to 5-hydroxymethylfurfural over biomass-based activated carbon catalyst

Abstract Selective and efficient dehydration of glucose to 5-hydroxymethylfurfural (HMF) has been widely explored research problem recently, especially from the perspective of more sustainable heterogeneous catalysts. In this study, activated carbon was first produced from a lignocellulosic waste material, birch sawdust. Novel heterogeneous catalysts were then prepared from activated carbon by adding Lewis or Bronsted acid sites on the carbon surface. Prepared catalysts were used to convert glucose to HMF in biphasic water:THF system at 160 °C. The highest HMF yield and selectivity, 51% and 78%, respectively, were obtained in 8 h with a catalytic mixture containing both Lewis and Bronsted a…