Kinetics of levulinic acid and furfural production from Miscanthus × giganteus

Integrated Humin Formation and Separation Studied In Situ by Centrifugation

We present a novel method for studying the integrated formation and separation of humins formed during the Brønsted acid-catalyzed conversion of fructose (here, at 90 °C with 20 wt % fructose and 5 wt % sulfuric acid). For the first time, we report the reaction carried out in situ during systematic centrifugation experiments, which allows combining humin formation and separation along with investigation of the phase behavior of humins. Analysis of the formed humin deposits employing scanning electron microscopy reveals deposits that are formed from a layer of monodisperse microspheres with a narrow diameter range of 0.9-1.9 μm. In the centrifugal force field, the microspheres partially coalesce, which increases with time and relative centrifugal force up to the formation of a thin and uniform layer of microspheres covering a continuous humin bulk phase with 80-90 μm thickness. These findings give evidence that humin spheres are highly viscous droplets rather than solid particles during formation. Our result is in line with the often-reported spherical and planar deposits formed during acidic carbohydrate conversion in technical systems and supports the development of strategies for deposit prevention, on the one hand, and humin preparation for material utilization, on the other hand.

Proposal, design, and cost analysis of a hydrogen production process from cellulose via supercritical water gasification

Hydrogen production from biomass, a renewable resource, has been attracting attention in recent years. We conduct a detailed process design for cellulose-derived hydrogen production via glucose using supercritical water gasification technology. Gasification of biomass in supercritical water offers advantages over conventional biomass conversion methods, including high gasification efficiency, elevated hydrogen molar fractions, and the minimization of drying process for wet biomass. In the process design, a continuous tank reactor is employed because the reaction in the glucose production process involves solids, and using a tube-type reactor may clog the reactor with solids. In the glucose separation process, glucose and levulinic acid, which cannot be separated by boiling point difference, are separated by using an extraction column. In the hydrogen separation process, the hydrogen purity, which could not be sufficiently increased with a single pressure swing adsorption (PSA) process, is increased to the target value by employing two sets of PSA columns. The overall utility cost is significantly reduced by $0.020/mol-H2 through heat integration. Our economic evaluation for this process results in a deficit of $0.015/mol-H2, as a price to be paid by the human for renewable hydrogen production from biomass at the present stage. By simply adopting the reported experimental condition, our process contains a large amount of water and sulfuric acid, which requires an enormous cost for the neutralizer, drying utility, and extractant. To improve the economic performance of the process, it is necessary to consider the reaction of cellulose solution at a higher concentration to reduce the burden of glucose separation. In addition, the effective use of the wasted hydrogen with a purity of about 95 vol% from the second PSA column may also improve the process economics. Whilst, the required energy cost for hydrogen production for our process is calculated to be significantly lower than those for other various representative hydrogen production methods: 0.37 (0.44) times less than that of steam reforming of methane with (without) CO2 capture, 0.15 times less than that of the water electrolysis by the electric power system, and 0.073 times less than that of electrolysis of water by wind power. This result implies the practical potential of our cellulose-based green hydrogen production scheme.

Highly efficient conversion of sunflower stalk-hydrolysate to furfural by sunflower stalk residue-derived carbonaceous solid acid in deep eutectic solvent/organic solvent system

Sunflower stalk was utilized as a source of raw material and catalyst for furfural production, and efficient conversion of xylose-rich hydrolysate into furfural was developed in an aqueous deep eutectic solvent/organic solvent medium by carbonaceous solid acid catalyst SO₄^2-/SnO₂-SSXR. The structural characteristics of SO₄^2-/SnO₂-SSXR was characterized by Brunauer-Emmett-Teller (BET), Scanning Electron Microscopy (SEM), Fourier-transform Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD), Pyridine Adsorption Fourier-transform Infrared (Py-IR) and Raman. Under the optimum catalytic conditions, furfural (110.1 mM) yield reached 82.6% in a ChCl-MAA/toluene medium at 180 °C in 15 min by 3.6 wt% SO₄^2-/SnO₂-SSXR. Additionally, quite importantly, SO₄^2-/SnO₂-SSXR, ChCl-MAA and toluene had good recyclability for furfural production. The potential catalytic path of xylose dehydration into furfural was proposed by co-catalysis with SO₄^2-/SnO₂-SSXR and ChCl-MAA. This study revealed high potential sustainable application of furfural production.

Synergistic Catalytic Effect of Sulphated Zirconia—HCl System for Levulinic Acid and Solid Residue Production Using Microwave Irradiation

The synergistic conversion of Miscanthus xGiganteous with sulphated zirconia and dilute hydrochloric acid was investigated. The sulphated zirconia was prepared using H2SO4 impregnation and characterised using X-ray Diffraction (XRD), Energy-dispersive X-ray (EDX), Scanning Electron Miscroscope (SEM) spectroscopy and nitrogen adsorption–desorption measurements. The microwave-assisted reaction was evaluated at various temperatures, reaction times and catalyst-to-biomass ratios, with and without the presence of trace HCl in the solution medium for the conversion of Miscanthus xGiganteous to levulinic acid. The highest levulinic acid yield of 63.8% was achieved at 160 °C, 80 min and a 2:1 catalyst-to-biomass ratio, with 10 mM HCl. The catalyst recyclability was investigated with and without calcination, finding that significant humin deposition on the catalyst surface likely caused catalyst deactivation. The post-reaction solid residue was also characterised using SEM, EDX, XRD, elemental composition and nitrogen adsorption–desorption measurements. Findings indicate that this residue could potentially be used as a soil amendment or as a fuel source. The synergistic conversion of real lignocellulosic biomass with sulphated zirconia and trace hydrochloric acid showed remarkable promise and should be investigated further.

Material utilization of green waste: a review on potential valorization methods

Considering global developments like climate change and the depletion of fossil resources, the use of new and sustainable feedstocks such as lignocellulosic biomass becomes inevitable. Green waste comprises heterogeneous lignocellulosic biomass with low lignin content, which does not stem from agricultural processes or purposeful cultivation and therefore mainly arises in urban areas. So far, the majority of green waste is being composted or serves as feedstock for energy production. Here, the hitherto untapped potential of green waste for material utilization instead of conventional recycling is reviewed. Green waste is a promising starting material for the direct extraction of valuable compounds, the chemical and fermentative conversion into basic chemicals as well as the manufacturing of functional materials like electrodes for electro-biotechnological applications through carbonization. This review serves as a solid foundation for further work on the valorization of green waste.

Production of Levulinic Acid from Cellulose and Cellulosic Biomass in Different Catalytic Systems

The reasonable and effective use of lignocellulosic biomass is an important way to solve the current energy crisis. Cellulose is abundant in nature and can be hydrolyzed to a variety of important energy substances and platform compounds—for instance, glucose, 5-hydroxymethylfurfural (HMF), levulinic acid (LA), etc. As a chemical linker between biomass and petroleum processing, LA has become an ideal feedstock for the formation of liquid fuels. At present, some problems such as low yield, high equipment requirements, difficult separation, and serious environmental pollution in the production of LA from cellulose have still not been solved. Thus, a more efficient and green catalytic system of this process for industrial production is highly desired. Herein, we focus on the reaction mechanism, pretreatment, and catalytic systems of LA from cellulose and cellulosic biomass, and a series of existing technologies for producing LA are reviewed. On the other hand, the industrial production of LA is discussed in depth to improve the yield of LA and make the process economical and energy efficient. Additionally, practical suggestions for the enhancement of the stability and efficiency of the catalysts are also proposed. The use of cellulose to produce LA is consistent with the concept of sustainable development, and the dependence on fossil resources will be greatly reduced through the realization of this process route.

Structural Effects of Cellulose on Hydrolysis and Carbonization Behavior during Hydrothermal Treatment

This study aims to investigate how the morphology of cellulose influences the hydrolysis and carbonization during hydrothermal treatment at temperatures between 180 and 240 °C. The morphology of cellulose, especially different crystallinities and degrees of polymerization, is represented by microcrystalline cellulose and α-cellulose. Kinetic analysis is considered a tool to allow the determination of the mechanisms of the two types of cellulose during the hydrothermal process. A kinetic model, in which cellulose is assumed to be hydrolyzed to a limited extent, is proposed. Five scenarios are used as models for pyrolysis of nonhydrolyzed cellulose that forms primary char, along with reaction pathways of hydrolyzable cellulose and its derivatives that latterly form secondary char. The morphologies of solid products are in good agreement with the results of the proposed model.

One-pot selective production of levulinic acid and formic acid from spent coffee grounds in a catalyst-free biphasic system

This study introduces the catalyst-free production of levulinic acid (LA) and formic acid (FA) from spent coffee grounds (SCGs) as a starting material in a biphasic system of 1,2-dichloroethane (DCE)-water at temperatures above 160 °C. In addition to the advantage of using the biphasic system attributed to the product equilibrium, DCE served as a source of hydrogen induced by subcritical water (SCW). The effect of temperature, the amount of DIW and DCE, and the pretreatment on SCG (raw or lipid extracted SCG (LE-SCG)) on the overall reaction and humin formation were studied. The maximum conversion of LA and FA was 47 and 29 w/w% of the total convertible monosaccharides in raw SCGs while 43 and 28 w/w% of the conversion were obtained at 180 °C when LE-SCG was used. The solvothermal effects of two media provides a non-catalytic route to utilize undried SCG for the production of LA and FA.

Tin oxide-coated transition metal oxide molecular wires for biomass conversion

Herein, acid catalysts were prepared by coating Sn oxide on molecular wires for the production of levulinic acid from cellulose.

Solid residue and by-product yields from acid-catalysed conversion of poplar wood to levulinic acid

This study examines the yields of solid residue and by-product from the microwave-assisted acid hydrolysis of lignocellulosic poplar wood for levulinic acid production. The aim of this study was to optimise levulinic acid production via response surface methodology (RSM) and also investigate the effect of reaction conditions on other products such as furfural, solid residue, formic acid and acetic acid yields. A maximum theoretical levulinic acid yield of 62.1% (21.0 wt %) was predicted when reaction conditions were 188 °C, 126 min and 1.93 M sulphuric acid, with a corresponding solid residue yield of 59.2 wt %. Furfural from the hydrolysis of hemicellulose was found to have significantly degraded at the optimum levulinic acid yield conditions. The investigation of formic acid yields revealed lower formic acid yields than stoichiometrically expected, indicating the organic acid reactions under microwave-assisted hydrolysis of lignocellulose. The solid residue yields were found to increase significantly with increasing reaction time and temperature. The solid residue yields under all conditions exceeded that of levulinic acid and, therefore, should be considered a significant product alongside the high-value compounds. The solid residue was further examined using IR spectra, elemental analysis and XRF for potential applications. The overall results show that poplar wood has great potential to produce renewable chemicals, but also highlight all by-products must be considered during optimization.

Hydro-Pyrolysis and Catalytic Upgrading of Biomass and Its Hydroxy Residue Fast Pyrolysis Vapors

Fast pyrolysis of Miscanthus, its hydrolysis residue and lignin were carried with a pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) followed by online vapor catalytic upgrading with sulfated ZrO2, sulfated TiO2 and sulfated 60 wt.% ZrO2-TiO2. The most evident influence of the catalyst on the vapor phase composition was observed for aromatic hydrocarbons, light phenols and heavy phenols. A larger amount of light phenols was detected, especially when 60 wt.% ZrO2-TiO2 was present. Thus, a lower average molecular weight and lower viscosity of bio-oil could be obtained with this catalyst. Pyrolysis was also performed at different pressures of hydrogen. The pressure of H2 has a great effect on the overall yield and the composition of biomass vapors. The peak area percentages of both aromatic hydrocarbons and cyclo-alkanes are enhanced with the increasing of H2 pressure. The overall yields are higher with the addition of either H2 or sulfated catalysts. This is beneficial as phenols are valuable chemicals, thus, increasing the value of bio-oil. The results show that the hydrolysis residue has the potential to become a resource for phenol production.

SAPO-34/5A Zeolite Bead Catalysts for Furan Production from Xylose and Glucose

SAPO-34 zeolite crystals were grown on zeolite 5A beads, characterized, and then used to produce furfural from xylose and 5-hydroxymethylfurfural (HMF) from glucose. The SAPO-34/5A bead catalysts resulted in moderate furfural and HMF yields of 45% from xylose and 20% from glucose (463 K; 3 h) and were easier to recover than the SAPO-34 powder catalyst. At 463 K, the SAPO-34/5A beads were more selective than 0.02 M sulfuric acid for producing HMF and, unlike the sulfuric acid system, no levulinic acid was formed. The SAPO-34/5A bead catalysts had no significant loss in activity after three rounds of recycle when water washed or heated overnight between reactions; however, the heat-treated beads did show signs of thermal stress after the second reuse. The SAPO-34/5A bead catalysts show promise for dehydration reactions to produce furfural and HMF from xylose and glucose, respectively, and tailoring the catalyst and the support bead could lead to even higher selectivities and yields.

Catalytic conversion of duckweed to methyl levulinate in the presence of acidic ionic liquids

In this study, an efficient strategy is proposed for selective methyl levulinate production from duckweed, a typical fast-growing aquatic microalgae in warm and humid regions, in the presence of acidic ionic liquids (ILs). The results show that IL structure has a significant effect on its acidic strength, which finally determines the process efficiency for levulinate methyl generation. With the optimized catalyst of [C₃H₆SO₃HPy]HSO₄, 88.0% duckweed is consumed, resulting in a comparable methyl levulinate yield of 73.7% and a process efficiency of 81.8% at 170 °C for 5 h. Furthermore, this process is substantially influenced by the reaction condition, particularly, it is significantly temperature-dependent. In addition, solvent has a remarkable intensified effect on the process efficiency, which dramatically decreases from 81.8 to 53.7% when methanol is replaced by water.

Sequential Production of Levulinic Acid and Porous Carbon Material from Cellulose

A sequential production of levulinic acid (LA) and porous carbon material (CM) from cellulose was conducted by a two-step process. The cellulose was first acid hydrolyzed, and the preferred reaction conditions required a severity factor of 4.0⁻4.5, in which the yields of LA, formic acid, and solid residue were 38 ± 3 wt%, 17 ± 3 wt%, and 15 ± 3 wt%, respectively. The solid residue was further used for CM preparation through pyrolysis, with or without ZnCl₂ activation. The ZnCl₂ activation promoted the formation of CMs with improved thermal stability, high surface area (1184⁻2510 m²/g), and excellent phenol adsorption capacity (136⁻172 mg/g). The used CM can be easily regenerated by a simple methanol Soxhlet extraction process, and a comparable phenol adsorption capacity of 97 mg/g was maintained for the 5th reusing. Finally, 100 g cellulose produced 40.5 g LA, 18.9 g formic acid and 8.5 g porous CM, with a total carbon utilization ratio reaching 74.4%.

Optimization of hydrothermal conversion of bamboo (Phyllostachys aureosulcata) to levulinic acid via response surface methodology

In this study, the dilute acid hydrolysis of lignocellulosic bamboo (Phyllostachys aureosulcata) particles to levulinic acid in a hydrothermal synthesis reactor is reported. The aim of the study was to optimize the reaction conditions for maximum levulinic acid production in terms of reaction time (t), reaction temperature (T) and HCl concentration (c_HCl) via Response Surface Methodology (RSM). A maximum levulinic acid yield of 9.46 w% was predicted at the following reaction conditions: t of 3 h, T of 160 °C and c_HCl of 0.37 M. A maximal experimental yield of levulinic acid of 10.13 w% was observed, which in respect to the cellulose fraction of the bamboo particles corresponds to 34.60 w% or 48.05 mol%. Furfural, which is formed by the hemicellulose fraction of bamboo, has not been observed within the boundaries of the RSM model, since it is already degraded under the given reaction conditions. The conversion of levulinic acid and furfural occurred more or less simultaneously, however, furfural was more vulnerable to degradation reactions at the given process conditions. Therefore, if both fractions (cellulose + hemicellulose) are required to be valorized, further optimization is required. However, the global results of this study provide insight in the potential of lignocellulosic bamboo as an alternative platform to fossil sources.

Evaluation of Separate and Simultaneous Kinetic Parameters for Levulinic Acid and Furfural Production from Pretreated Palm Oil Empty Fruit Bunches

Palm oil empty fruit bunches (POEFBs) can be converted into levulinic acid (LA) and furfural, which are among the top building-block chemicals. The purpose of this study was to investigate separate and simultaneous kinetic model parameters for LA and furfural production from POEFBs, which were pretreated by soaking in aqueous ammonia (SAA). The highest LA yield, which was obtained at a reaction temperature of 170°C after 90 min in an acidic solution with a concentration of 1 M, was 52.1 mol%. The highest furfural yield was 27.94 mol%, which was obtained at a reaction temperature of 170°C after 20 min in an acidic solution with a concentration of 0.5 M. SAA pretreatment affected activation energy in glucose degradation reactions and favoured direct conversion of hemicellulose to furfural. The activation energy of LA production (EakHMF) increases with higher acid catalyst concentration, and the activation energy of furfural production (EakXYN) decreases with higher acid concentration. These trends in the activation energy occurred in both separate and simultaneous kinetic models. Simultaneous kinetic model is better to calculate kinetic parameters of LA and furfural production than separate kinetic models because the simultaneous kinetic model had a lower sum of square error (SSE) when estimating kinetic parameters.

Kinetics study of levulinic acid production from corncobs by tin tetrachloride as catalyst

Levulinic acid (LA) is an ideal platform chemical that can be produced through acid-catalyzed dehydration and hydrolysis of hexose sugars obtained from lignocellulosic materials. In this study, SnCl₄ was identified as an efficient catalyst for LA production and the reaction kinetics was investigated in a single water phase under different reaction conditions. The Box-Behnken design response surface methodology (RSM) was applied to determine the optimized reaction conditions and three individual variables including reaction temperature, duration, and catalyst concentration were evaluated. An appealing LA yield of 76.0% was achieved at 193 °C and 17 min with 82 mM SnCl₄ catalyst. A kinetics model was developed to predict the yields of glucose, HMF, and LA, which are tally with the experimental results. The analysis of the related kinetic parameters and the results of the RSM experiment helped to provide insights into the interplay between various reaction steps with SnCl₄ as catalysts.

Conversion of Levulinic Acid from Various Herbaceous Biomass Species Using Hydrochloric Acid and Effects of Particle Size and Delignification

Acid catalyzed hydrothermal conversion of levulinic acid (LA) from various herbaceous materials including rice straw (RS), corn stover (CS), sweet sorghum bagasse (SSB), and Miscanthus (MS) was evaluated. With 1 M HCl, 150 °C, 5 h, 20 g/L solid loading, the yields of LA from untreated RS, CS, SSB and MS based on the glucan content were 60.2, 75.1, 78.5 and 61.7 wt %, respectively. It was also found that the particle size had no significant effect on LA conversion yield with >3 h reaction time. With delignification using simulated green liquor (Na2CO3-Na2S, 20 wt % total titratable alkali (TTA), 40 wt % sulfidity) at 200 °C for 15 min, lignin removal was in the range of 64.8–91.2 wt %. Removal of both lignin and xylan during delignification increased the glucan contents from 33.0–44.3 of untreated biomass to 61.7–68.4 wt % of treated biomass. Delignified biomass resulted in much lower conversion yield (50.4–56.0 wt %) compared to 60.2–78.5 wt % of untreated biomass. Nonetheless, the concentration of LA in the product was enhanced by a factor of ~1.5 with delignification.

Experimental and Kinetic Modeling Studies on the Conversion of Sucrose to Levulinic Acid and 5-Hydroxymethylfurfural Using Sulfuric Acid in Water

We here report experimental and kinetic modeling studies on the conversion of sucrose to levulinic acid (LA) and 5-hydroxymethylfurfural (HMF) in water using sulfuric acid as the catalyst. Both compounds are versatile building blocks for the synthesis of various biobased (bulk) chemicals. A total of 24 experiments were performed in a temperature window of 80-180 °C, a sulfuric acid concentration between 0.005 and 0.5 M, and an initial sucrose concentration between 0.05 and 0.5 M. Glucose, fructose, and HMF were detected as the intermediate products. The maximum LA yield was 61 mol %, obtained at 160 °C, an initial sucrose concentration of 0.05 M, and an acid concentration of 0.2 M. The maximum HMF yield (22 mol %) was found for an acid concentration of 0.05 M, an initial sucrose concentration of 0.05 M, and a temperature of 140 °C. The experimental data were modeled using a number of possible reaction networks. The best model was obtained when using a first order approach in substrates (except for the reversion of glucose) and agreement between experiment and model was satisfactorily. The implication of the model regarding batch optimization is also discussed.

Integrated production of furfural and levulinic acid from corncob in a one-pot batch reaction incorporating distillation using step temperature profiling

Integrated production of furfural and levulinic acid (LA) in one pot through two-step temperature profiling.

Efficient catalytic system for the direct transformation of lignocellulosic biomass to furfural and 5-hydroxymethylfurfural

A feasible approach was developed for the co-production of 5-hydroxymethylfurfural (5-HMF) and furfural from corncob via a new porous polytriphenylamine-SO₃H (SPTPA) solid acid catalyst in lactone solvents. XRD, SEM, XPS, N₂ adsorption-desorption, elemental analysis, TG-DTA, acid-base titration and FTIR spectroscopy techniques were used to characterize the catalyst. This study demonstrates and optimizes the catalytic performance of SPTPA and solvent selection. SPTPA was found to exhibit superior catalytic ability in γ-valerolactone (GVL). Under the optimum reaction conditions, simultaneously encouraging yields of furfural (73.9%) and 5-HMF (32.3%) were achieved at 448K. The main advantages of this process include reasonable yields of both 5-HMF and furfural in the same reaction system, practical simplicity for the raw biomass utilization, and the use of a safe and environmentally benign solvent.

Continuous hydrogenation of ethyl levulinate to γ-valerolactone and 2-methyl tetrahydrofuran over alumina doped Cu/SiO2 catalyst: the potential of commercialization

Hydrogenation of levulinic acid (LA) and its esters to produce γ-valerolactone (GVL) and 2-methyl tetrahydrofuran (2-MTHF) is a key step for the utilization of cellulose derived LA. Aiming to develop a commercially feasible base metal catalyst for the production of GVL from LA, with satisfactory activity, selectivity, and stability, Al₂O₃ doped Cu/SiO₂ and Cu/SiO₂ catalysts were fabricated by co-precipitation routes in parallel. The diverse physio-chemical properties of these two catalysts were characterized by XRD, TEM, dissociative N₂O chemisorptions, and Py-IR methods. The catalytic properties of these two catalysts were systematically assessed in the continuous hydrogenation of ethyl levulinate (EL) in a fixed-bed reactor. The effect of acidic property of the SiO₂ substrate on the catalytic properties was investigated. To justify the potential of its commercialization, significant attention was paid on the initial activity, proper operation window, by-products control, selectivity, and stability of the catalyst. The effect of reaction conditions, such as temperature and pressure, on the performance of the catalyst was also thoroughly studied. The development of alumina doped Cu/SiO₂ catalyst strengthened the value-chain from cellulose to industrially important chemicals via LA and GVL.

High concentration levulinic acid production from corn stover

In this study, a novel approach is presented for high concentration levulinic acid (LA) production from biomass hydrolysate.

Non-stoichiometric formation of formic and levulinic acids from the hydrolysis of biomass derived hexose carbohydrates

We demonstrate that formic and levulinic acids are not formed stoichiometrically from the acid catalysed transformations of hexose carbohydrates.

Analysis of the lignocellulosic components of biomass residues for biorefinery opportunities

The present study aims to identify the renewable resources available in Brazil such as açai seed, coconut husks, coffee husks, rice husks, eucalyptus sawdust, grass, soy peel, bamboo, banana stems and banana stalks. To identify such renewable energy sources, samples were examined for their physical and chemical characteristics using X-ray diffraction (XRD), proximate and ultimate analyses, thermogravimetric analysis (TGA), calorific value determination, near-infrared (NIR) spectroscopy, UV spectroscopy, high-pH anion-exchange chromatography (HPAEC-PAD) and accelerated solvent extraction (ASE). Among the biomasses, açai and coffee exhibited higher total sugar content, 67.70% and 62.55%, respectively. Sawdust exhibited low ash, along with the highest calorific value and lignin content. The highest glucose contents were observed in bamboo (44.65%) and sawdust (38.80%). The maximum yield for the bioproducts levulinic acid (LA), formic acid (FA) and furfural were estimated; açai exhibited the highest yield of LA and FA, while coffee exhibited the best furfural yield. All of these properties indicate that the residues are potential candidates for bioenergy production.

Conversion of hemicellulose sugars catalyzed by formic acid: kinetics of the dehydration of D-xylose, L-arabinose, and D-glucose

The pre-treatment of lignocellulosic biomass produces a liquid stream of hemicellulose-based sugars, which can be further converted to high-value chemicals. Formosolv pulping and the Milox process use formic acid as the fractionating agent, which can be used as the catalyst for the valorisation of hemicellulose sugars to platform chemicals. The objective of this study was to investigate the reaction kinetics of major components in the hemicelluloses fraction of biomass, that is, D-xylose, L-arabinose and D-glucose. The kinetics experiments for each sugar were performed at temperatures between 130 and 170 °C in various formic acid concentrations (10-64 wt %). The implications of these kinetic models on the selectivity of each sugar to the desired products are discussed. The models were used to predict the reaction kinetics of solutions that resemble the liquid stream obtained from the fractionation process of biomass using formic acid.

Levulinic acid production from Cicer arietinum, cotton, Pinus radiata and sugarcane bagasse

Abundantly available agricultural wastes were successfully transformed into a key strategic chemical levulinic acid. Depending on the biomass type, possibility of 19–44 wt% levulinic acid is demonstrated.