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Chemoselective hydrogenation of biomass platform molecules into value-added chemicals and fuels is essential for the exploitation of biomass, and SBA-15 based metal catalysts with hydrogenation centers and acid sites seem promising in this regard. Valeric acid (VA) is the most important platform molecule for valeric biofuels and value-added chemicals production. The main issue with using such bifunctional catalysts for biomass conversion is maintaining the catalyst's stability in the liquid phase under harsh conditions. In-addition, direct one-pot selective hydrogenation of levulinic acid (LA) into VA synthesis is challenging due to its complex reaction conditions involved. Herein, we design a bifunctional mesoporous catalysts (SBA-15 mesoporous material doped with various metals Nb, Ti, and Zr) investigated for this reaction under the vapour phase. Different instrumental approaches were used to examine the structure, phase composition, morphology, and surface elemental analyses of catalysts as-prepared. Among those catalysts, Zr-doped mesoporous SBA-15 catalyst showed the 91% conversion of LA and the 68% selectivity toward VA and promising stability in a 52 h time on-stream run. Metal dispersion inside the SBA-15 and their surface acidity (sufficient number of acid sites and surface-active metal oxide species) and higher surface area are beneficial for the selectivity of VA. This work offers a highly-efficient bifunctional catalyst for selective hydrogenation of biomass feedstocks.

The electrochemical conversion of biobased levulinic acid (LA) into renewable chemicals and biofuel precursors represents an important and reasonable alternative to the high temperature conventional catalytic processes of great importance for the development of a sustainable and cost-effective biorefinery. The establishment of the mechanism of levulinic acid reduction is a promising strategy in choosing the optimal electrocatalyst for the redox-transformation of biobased substrates. Herein, we report a new approach to study an electrochemical reduction mechanism of levulinic acid using of proton-deficient non-aqueous reaction media. The electrochemical reduction of levulinic acid to γ-valerolactone (GVL) and valeric acid (VA) in aqueous and organic solutions on various electrodes (glassy carbon, graphite, Al, Pb) was studied. The mechanism of LA electrochemical reduction and major reaction products significantly was found to depend on the solvent, the presence of proton donors, the material of cathode, and the magnitude of the applied potential. In an aqueous solution the process proceeded with the formation of valeric acid on all the electrodes studied. In acetonitrile in the presence of protons, the electrochemical reduction of LA proceeded by various mechanisms, both with the participation of atomic hydrogen and the protonated form of LA, and led to the formation of GVL and/or VA. The difference (ΔE1/2) between the reduction half-wave potential of protons and levulinic acid was found to play an important role in the reduction pathway of LA carbonyl group. At a large ΔE1/2, as in the case of the GC electrode, the LA reduction resulted in the GVL formation. LA can be completely reduced to VA by transferring four electrons due to the close reduction potentials of protons and LA (a low ΔE1/2), as on a Pb electrode. The pathway depends on the conditions of the reduction process and can be estimated based on electrochemical data obtained in the study of reaction products in organic media.

In the present study, the performance of the pervaporation membrane reactor during the esterification reaction of levulinic acid with ethanol to produce ethyl levulinate was modeled based on computational fluid dynamics (CFD) method. Global warming due to the greenhouse effect is now recognized as an important environmental issue. Important factors in the greenhouse effect are the production of sulfur oxides, nitrogen oxides and carbon dioxide, which are produced after the combustion of fuel. Therefore, one of the solutions to solve this problem is a biomass-based additive that leads to better performance of the fuel during combustion and prevents the production of these gases in the atmosphere. Therefore, a symmetric two-dimensional model is provided for the pervaporation membrane reactor (PVMR). In this regard, after modeling and simulating the performance of a fixed bed reactor and comparing its results with laboratory data, it was observed that a good agreement (1% error) was obtained between the theoretical and laboratory results. In order to better understanding of the efficiency of the pervaporation membrane reactor during the esterification reaction, the effect of different operating parameters (reaction temperature, feed flow rate, feed molar ratio and catalyst loading) on the levulinic acid conversion and water removal percentages have been investigated. As a general result in all operating conditions, the pervaporation membrane reactor has performed better than a conventional fixed bed (TR) reactor.

Glucose is one of the primary derivative products from lignocellulosic biomass, which is abundantly available. Glucose has excellent potential to be converted into valuable compounds such as ethanol, sorbitol, gluconic acid, and levulinic acid (LA). Levulinic acid is an exceptionally promising green platform chemical. It comprises two functional groups, ketone and carboxylate, acting as highly reactive electrophiles for a nucleophilic attack. Therefore, it has extensive applications, including fuel additives, raw materials for the pharmaceutical industry, and cosmetics. This study reports the reaction kinetics of LA synthesis from glucose catalyzed by hydrochloric acid (HCl), a Bronsted acid, that was carried out under a wide range of operating conditions; i.e. the temperature of 140–180 °C, catalyst concentration of 0.5–1.5 M, and initial glucose concentration of 0.1–0.5 M. The highest LA yield of 48.34 % was able to be obtained from an initial glucose concentration of 0.1 M and by using 1 M HCl at 180 °C. The experimental results show that the Bronsted acid-catalyzed reaction pathway consists of glucose decomposition to levoglucosan (LG), conversion of LG to 5-hydroxymethylfurfural (HMF), and rehydration of HMF to LA. The experimental data yields a good fitting by assuming a first-order reaction model. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

The massive use of petroleum and its possible exhaustion are driving the current research trend to study alternative raw materials from biomass for organic reactions. In this context, the present article presents a study of the catalytic esterification of levulinic acid, a platform molecule, with ethanol. Metal-organic framework (MOF) type compounds UiO-66-NH2 have been synthesized. Zirconium was incorporated, using zirconium chloride as a metal precursor, together with 2-aminoterephthalic acid as an organic binding agent. An alternative route of synthesis was proposed using more favorable conditions from an economic and environmental point of view, replacing dimethylformamide by 50 and 75% acetone as substitute solvent. The physicochemical properties of the materials were evaluated by X-ray diffraction (XRD), Infrared Spectrometry with Fourier Transform (FTIR), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), microwave plasma atomic emission spectroscopy (MP-AES) and N2 adsorption to understand their morphology, crystalline, chemical and pore structure. The progress of the reaction was followed by gas chromatography and mass spectroscopy. The catalytic activity result of MOF25% in autoclave reactor, showed 100% of selectivity to ethyl levulinate and a turnover number (TON) of 66.18 moles of product/moles of Zr. This good catalytic performance obtained by partial solvent replacement in the synthetic material provides a more economical and eco-friendly process for ethyl levulinate generation.

Levulinic acid is a reactive polar organic compound deemed as a building block for several products with relevant applications, replacing traditional substances in the petrochemical industry. Considered a platform molecule, levulinic acid is industrially produced from the acid hydrolysis of biomass - mainly plant-based - using hydrochloric or sulfuric acid in homogenous catalysis. However, considering the World Market for levulinic acid is expected to reach US$ 71.9 million in 2027, growing annually at 14.1%, and its applications in agriculture, pharmaceuticals, plasticizers, cosmetics, and food additives, the development of alternative production processes is sought. Hence, a survey was performed on publications considering the alternatives for biomass-based levulinic acid production processes: I) alternative homogenous catalysts to avoid using noble materials in the reactor; II) heterogeneous catalysis to facilitate and reduce the catalyst’s separation and recovery costs; III) ionic liquids, exploiting their high solvency, stability, and catalytic capacity. Additionally, biomass alternatives for obtaining levulinic acid are presented, showing that other agricultural residues and animal biomass options are being considered, targeting process flexibilization while reducing costs and producing derivatives at more competitive prices. Thus, it can be stated that levulinic acid is an important platform molecule for biorefineries’ economics, replacing fossil fuels with renewable raw materials.

Silica functionalized with sulfonic acid catalyst (SiO2−SO3H) was synthesized through a one-pot method and evaluated as the catalyst material for esterification of levulinic acid in an excess amount of ethanol. Sodium silicate solution was used as the silica source, and then a silane coupling agent, namely GPTMS, was used to incorporate the sulfonic group of 2-aminoethanesulfonic acid (AS) into the silica. Functionalization of AS using GPTMS in the slightly acidic condition has been successfully carried out based on the characterization with FTIR, SEM-EDX, and TGA measurements. Catalyst with the AS to SiO2 molar ratio of 5:6 (SiO2−SO3H(5)) showed the highest acid content (1.02 mmol g–1) and the highest conversion of levulinic acid (70%). The reaction followed pseudo-first-order with the rate constant of 0.00414 min–1. Catalyst material was regenerated by washing with alcohol and water, and the catalyst material can be reused at least for 3 cycles. From this study, the SiO2−SO3H produced from a green process is an effective catalyst to produce esters used in fuel additives.

The design of robust catalyst was of great significance for the valorization of biomass platforms. Herein, an efficient Co@mSiO2−CN catalyst was constructed via a simple impregnation‐mixing‐pyrolysis strategy, which could give 100 % yield of γ‐valerolactone from levulinic acid for no less than five cycles under a relatively mild reaction conditions (160 °C, 1.5 MPa H2,3 h).The results of catalyst characterizations and comparative experiments showed that the introduction of nitrogen‐doped carbon materials promoted the dispersion of Co and enhanced the Lewis acidity of the catalyst, thereby promoting the dissociation of H2 and the activation of C−O, respectively. The synergistic effect between the hydrogenation metal sites and the Lewis acidic site ensures excellent activity of the catalyst. [ABSTRACT FROM AUTHOR]

Design catalytic materials with high Lewis acid/base sites for catalytic transfer hydrogenation (CTH) of levulinic acid (LvA) to γ-valerolactone (GVL) is highly demanded but challenging. Herein, we report a concept of metal ion-polymer hybridization to design a tea polyphenol (TP) and HfCl 4 co-doped polyacrylonitrile (PAN) nanofiber (Hf@PAN-TP) via electrospinning technique. Comprehensive characterization revealed the well coordination between hafnium ions and phenolic hydroxyl groups of TP on PAN fiber, which promoted the formation of Lewis acid and Lewis base sites. As expected, a satisfactory GVL yield of 99.1% with 100% of LvA conversion was obtained using isopropanol as a hydrogen donor at 170 °C in 5 h, and the catalytic activity remained unchanged for five cycles. The kinetic study revealed the lower activation energy for CTH of LvA to GVL (33.5 kJ/mol), demonstrating the outstanding GVL formation rate of 3383.9 μmol/g.h. Based on the systematical combine of catalyst characterization and catalytic behavior, the structure-function relationship and reaction mechanism were proposed. More gratifyingly, Hf@PAN-TP was applicable for catalytic reduction of various carbonyl compounds, demonstrating a great potential for upgrading biomass-derived aldehydes/ketones. The concept of metal ion-polymer hybridization to design Hf@PAN-TP nanofiber and its application in CTH of LvA to GVL. [Display omitted] [ABSTRACT FROM AUTHOR]

Hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL) is regarded as the bridge between bio-refinery and the traditional petroleum industry. In recent years, non-precious metal-based catalysts for LA hydrogenation to GVL have attracted much attention owing to their low cost and high efficiency. Metal-involving catalytic hydrogenation of LA is the rate-determining step in the production of GVL, and thus the active site structure of metal-based catalysts governs the overall catalytic performance. Herein, non-precious metal-based catalytic systems including Cu, Zr, Co and Ni are classified into single metal (M = Ni, Cu and Co), bimetallic (Cu–Ni, Ag–Ni, Cu–Co and Co–Zn), metal-heteroatom (M–O and M–N) and heterostructured (CePO4/CoP2 and Ni/NiO) catalysts according to the type of active site structure. The correlation of active site structure with catalytic activity is discussed emphatically, and its relationship with stability is also referred to in terms of strong metal–support interaction, bimetallic synergism, core–shell structure and heterojunction. This review provides an important guide for the rational design of high-performance non-precious metal-based catalysts for the LA-to-GVL process. [ABSTRACT FROM AUTHOR]

Herein, we report a stable catalyst with Ru single atoms anchored on a one-dimensional carbon fiber@graphitic carbon nitride hierarchy, by assembling wet wipes composed of fiber-derived carbon fiber (CF), melamine-derived graphitic carbon nitride (g-C3N4) and RuCl3 before NaBH4 reduction. The atomically dispersed Ru species (3.0 wt%) are tightly attached via N-coordination provided by exterior g-C3N4 nanosheets, and further stabilized by the interior mesoporous CF. The obtained CF@g-C3N4–Ru SAs catalyst can be cycled six times without notable leaching of Ru or loss of GVL yield in the acidic media. This catalyst is more stable than Ru nanoparticles supported on CF@g-C3N4, as well as Ru single atoms anchored on CF and g-C3N4, and proves to be one of the most efficient metal catalysts for aqueous LA hydrogenation to γ-valerolactone (GVL). The isolated Ru atoms by strong N-coordination, and their enhanced electron/mass transfer afforded by the one-dimensional hierarchy, can be responsible for the excellent durability of CF@g-C3N4–Ru SAs under harsh reaction conditions. [ABSTRACT FROM AUTHOR]

Three common solid wastes (waste incineration fly ash, sewage sludge, and polluted soil) were the raw materials used in the synthesis of a geopolymer–type zeolite–like product, which was then used as a catalyst carrier to prepare a nickel hydrogenation catalyst for the catalytic hydrogenation of levulinic acid to γ–valerolactone. Under optimum synthesis conditions, the synthesized geopolymer zeolite has excellent structure and performance. The characterization results show that the composites have a three–dimensional network structure, and the pore structure is homogeneous mesoporous or microporous. In this work, the results of catalytic hydrogenation show that the yield of γ–valerolactone can achieve up to 94% using the synthesized catalyst, which is comparable to that of commercial catalysts and the concentrations of typical polluting heavy metals of Cu, Zn, Pb, and Cd in the reaction solution were all below the emission concentration limit (Class I standard) after five cycles of reaction. In summary, this geopolymer–type zeolite–like catalyst is cheap and has excellent performance; it is, therefore, expected to be widely used in catalysis instead of commercial carriers. [ABSTRACT FROM AUTHOR]

This study evaluated the synthesis, characterization, and activity of fluorinated titanium dioxide materials (TiO2 - F1% and TiO2 -- F5%) in-situ modified by the sol-gel method in the esterification reaction of levulinic acid conducted by catalytic and photocatalytic processes. The physicochemical properties of the materials were determined by X-ray diffraction, UV--Vis diffuse reflectance spectroscopy, thermal analysis, and pyridine adsorption. It was found that the inclusion of fluoride anion causes a decrease in the levulinic acid conversion by photocatalytic reaction; however, in the catalytic activation, a slight increase in the conversion using the fluoride materials was observed. Finally, the reaction in the presence of halogenated solvents (CCl4) by photolysis reaction favors a conversion of 100% in 1h. [ABSTRACT FROM AUTHOR]

Commercial niobium and synthesized zirconium phosphates were tested as water-tolerant heterogeneous acid catalysts in the hydrothermal conversion of different bio-based substrates. Different acid-catalyzed reactions were performed using biomass-derived model compounds and more complex real lignocellulosic biomasses as the substrate. The conversion of glucose and cellulose was preliminarily investigated. Then, a wide plethora of raw lignocellulosic biomasses, such as conifer wood sawdust, Jerusalem artichoke, sorghum, miscanthus, foxtail millet, hemp and Arundo donax, were valorized towards the production of water-soluble saccharides, 5-hydroxymethylfurfural (HMF), levulinic acid (LA) and furfural. The different catalytic performances of the two phosphates were explained on the basis of their acid features, total acidity, Brønsted/Lewis acid sites ratio and strength. Moreover, a better insight into their structure–acidity relationship was proposed. The different acid properties of niobium and zirconium phosphates enabled us to tune the reaction towards target products, achieving from glucose maximum HMF and LA yields of 24.4 and 24.0 mol%, respectively. Remarkably, when real Jerusalem artichoke biomass was adopted in the presence of niobium and zirconium phosphate, maximum yields of furanic compounds and cellulose-derived sugars of 12.7 and 50.0 mol%, respectively, were obtained, after only 1 h of reaction. The synthesized hydrolysates, which were found to be rich in C5 and C6 carbohydrates, can be better exploited for the cascade production of more added-value bio-products. [ABSTRACT FROM AUTHOR]

[Display omitted] • N -doped carbon nanospheres (HPNC) with hierarchical porous structure was prepared. • Ultrafine Ru NPs were anchored on the HPNC with high dispersion. • Levulinic acid can be hydrogenated to γ-valerolactone by Ru/HPNC catalyst. • The reaction conditions are solvent-free and environmentally friendly. • Ru/HPNC catalyst can be easily recovered and reused without loss of activity. The catalytic transformation of the biomass platform compound levulinic acid (LA) to γ-valerolactone (GVL) is a vital reaction to produce related renewable chemicals and fuels. Developing stable catalysts with highly dispersed and accessible ultrafine metal nanoparticle (NP) active sites for the hydrogenation of LA under solvent-free conditions is still a major challenge. Herein, a versatile nano-emulsion self-assembly method was employed to fabricate N -doped carbon nanospheres with a high specific surface area and hierarchically porous structure. Ultrafine Ru NPs were successfully anchored on the hierarchal porous N -doped carbon nanospheres (HPNC) with high dispersion. The obtained Ru/HPNC catalyst exhibited excellent catalytic performance for LA hydrogenation to GVL under solvent-free conditions with outstanding reusability. In contrast, Ru NPs embedded in other supports (including activated carbon and carbon nanotubes) were observed to be less effective under the same reaction conditions. The superior catalytic performance of the Ru/HPNC catalyst is due to the hierarchically porous catalyst structure, and accessible ultrafine Ru active sites which can promote the activation of C O bonds and H 2 absorption during the catalytic process. The reaction pathway of LA hydrogenation to GVL is clearly researched by theoretical calculations. Thus, the current work provides a facile strategy for the synthesis of highly dispersed ultrafine metal NP-based catalysts for an important biomass transformation. [ABSTRACT FROM AUTHOR]

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BACKGROUND: Levulinic acid, an important platform compound, is extensively used in textiles, dyes, antifreeze, animal feed, solvents and food additives. However, the use of lignocellulosic biomass to produce levulinic acid is difficult because of poor accessibility to cellulose and low hydrolytic yield. Thus a viable hydrolysis strategy and a suitable catalyst must be developed. RESULTS: In this study, a bifunctional solid acid catalyst (HTC‐SO3H) containing both cellulose binding sites (Cl, COOH and OH) and catalytic sites (SO3H) was prepared by a carbonization–grafting–oxidization method. X‐ray photoelectron spectroscopy and Fourier transform infrared characterization confirmed the existence of Cl and the successful modification of the SO3H grafted hydrothermal carbon. The hydrogen bonds formed between cellulose and the binding sites (Cl, OH and COOH) in the catalyst showed synergistic effects with the catalytic sites (SO3H), leading to efficient hydrolysis of the furfural residue. A total of 74.81% (non‐magnetic) and 70.18% (magnetic) levulinic acid yields were obtained after hydrolysis at 190 °C and 180 min in γ‐valerolactone–H2O (1:1, v/v). Magnetic catalysts were synthesized using a co‐precipitation method. Catalysts were recycled without any obvious reduction in catalytic activity. CONCLUSION: Using sucralose as a raw material, the as‐synthesized bifunctional solid acid catalyst improved the accessibility to cellulose and increased levulinic acid yield. Moreover, the grafted SO3H formed by hydroxyl hydration condensation exhibited superior stability. This study provides a valuable strategy for the efficient hydrolysis of lignocellulosic biomass. © 2022 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

We report the first well‐defined homogeneous copper‐based catalyst for levulinic acid (LVA) hydrogenation using complex [(PPh3)2Cu(k2‐O,O‐LVA)] as a copper source and (1,2‐bis(diisopropyl phosphino)ethane (dippe) as an ancillary ligand. This catalytic precursor has high activity in LVA hydrogenation and yields γ‐valerolactone (GVL) under relatively mild reaction conditions (24 h, 140 °C) in a base‐free system using H2 (300 psi) as a reductant. Under optimized conditions, GVL was obtained with excellent yield (>99 %) and selectivity (>99 %) using a low catalytic load (0.025 mol %), allowing a TON=4000. [ABSTRACT FROM AUTHOR]

Monometallic (Cu, Ni) and bimetallic (Cu-Ni) catalysts supported on KIT-6 based mesoporous silica/zeolite composites were prepared using the wet impregnation method. The catalysts were characterized using X-ray powder diffraction, N2 physisorption, SEM, solid state NMR and H2-TPR methods. Finely dispersed NiO and CuO were detected after the decomposition of impregnating salt on the silica carrier. The formation of small fractions of ionic Ni2+ and/or Cu2+ species, interacting strongly with the silica supports, was found. The catalysts were studied in the gas-phase upgrading of lignocellulosic biomass-derived levulinic acid (LA) to γ-valerolactone (GVL). The bimetallic, CuNi-KIT-6 catalyst showed 100% LA conversion at 250 °C and atmospheric pressure. The high LA conversion and GVL yield can be attributed to the high specific surface area and finely dispersed Cu-Ni species in the catalyst. Furthermore, the catalyst also exhibited high stability after 24 h of reaction time with a GVL yield above 80% without any significant change in metal dispersion. [ABSTRACT FROM AUTHOR]

A titanocene-catalyzed Levulinic Acid hydrogenation was developed with excellent yield to produce γ-Valerolacctone. Mechanistic studies unveiled an alkoxide Ti (III) complex species performing the catalytic turnover. [Display omitted] • Catalysis with an earth abundant metal. • Mild reaction conditions. • High yield and selectivity. • Key catalytic intermediates. A titanium-based catalytic system using the commercially available titanocene complex [Cp 2 TiCl 2 ], was developed for hydrogenation of levulinic acid to γ-valerolactone (GVL), using mild reaction conditions (100 °C and 100 psi) and excellent yields (>99 %). Key mechanistic insights, including the main species involved in the catalytic cycle, are also documented. [ABSTRACT FROM AUTHOR]

Studies on the electrochemical hydrogenation (ECH) of levulinic acid (LA) to valeric acid (VA) or γ-valerolactone (GVL) have mainly focused on the electrochemical reduction of LA in acidic aqueous solutions. However, the narrow range of applied potentials has hindered understanding of some mechanistic aspects of LA electrochemical conversion. Earlier, we discovered that employing proton-deficient non-aqueous reaction media provides more comprehensive insights into the mechanism of LA electrochemical reduction. Here, we conducted further investigations into the LA electroreduction process using cyclic voltammetry in various organic solvents on a Pt electrode and on various electrode materials in acetonitrile, both with and without the addition of proton donors. The products of the ECH processes were identified using HPLC. The solvent nature, the presence of proton donors, the electrode material, and the applied potential strongly influence the LA electroreduction process. This study reveals that LA, in the presence proton donors, can undergo electrochemical reduction through different pathways, depending on the difference (ΔE 1/2 ) between the reduction half-wave potential of protons and LA on a certain electrode. When the difference is large, the LA reduction is incomplete and the formation of GVL is observed. Under the close reduction potentials of protons and LA, LA can be completely reduced to VA., (© 2024 Wiley-VCH GmbH.)

Alkyl levulinate is a biomass-based chemical compound used as a fuel additive. This research aims to produce ethyl levulinate from levulinic acid and ethanol using esterification with the assistance of a heterogeneous sulfonated carbon catalyst. The carbon sulfonate catalyst is obtained from corncob waste that has undergone carbonization at 300 °C and sulfonation using sulfuric acid at a temperature of 150 °C for 8 h. The catalyst is used for esterification with predetermined operating variables using Box-Behnken Design (BBD) on the response surface methodology (RSM). The result shows significant variables for ethyl levulinate esterification are catalyst loading and esterification time. The FTIR analysis indicates the presence of S=O bonds in the sulfonated carbon catalyst. The XRD and SEM analysis shows that the sulfonated carbon catalyst is in amorphous and mesoporous form. Catalyst reusability demonstrates that the corncob-derived carbon sulfonate catalyst can be used up to 3 times. The optimum condition for esterification is 9 h of reaction, 10 % catalyst loading, and a molar ratio of levulinic acid to ethanol of 1:10, which has 83.15 % conversion. These results present the optimum parameter conditions for an efficient heterogeneous catalyst from corncob for producing ethyl levulinate., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

This work reports synthesis of an efficient MoO3/ZnCo2O4@CeO2, bifunctional heterogeneous catalyst for profitable conversion of corncob biomass into Levulinic acid. The physiochemical properties of the catalyst were studied by TG-DTA, BET, XRD, FESEM/SEM, EDX-Mapping and TPD to correlate them with the catalytic activity. The results exposed that the synthesized catalyst showed improved catalytic performance, providing Levulinic acid yield of 70.1% under 8 wt% catalyst loading at 200 °C temperature for 220 min. Moreover, the catalyst presented sufficient reusability and recycled for at least 3 times for Levulinic acid production from the biomass without any loss in the catalytic activity.

The biomass-derived platform chemicals furfural and 5-(hydroxymethyl)furfural (HMF) may be converted to α-angelica lactone (AnL) and levulinic acid (LA). Presently, LA (synthesized from carbohydrates) has several multinational market players. Attractive biobased oxygenated fuel additives, solvents, etc., may be produced from AnL and LA via acid and reduction chemistry, namely alkyl levulinates and γ-valerolactone (GVL). In this work, hierarchical hafnium-containing multifunctional Linde type L (LTL) related zeotypes were prepared via top-down strategies, for the chemical valorization of LA, AnL and HMF via integrated catalytic transfer hydrogenation (CTH) and acid reactions in alcohol medium. This is the first report of CTH applications (in general) of LTL related materials. The influence of the post-synthesis treatments/conditions (desilication, dealumination, solid-state impregnation of Hf or Zr) on the material properties and catalytic performances was studied. AnL and LA were converted to 2-butyl levulinate (2BL) and GVL in high total yields of up to ca. 100%, at 200°C, and GVL/2BL molar ratios up to 10. HMF conversion gave mainly the furanic ethers 5-(sec-butoxymethyl)furfural and 2,5-bis(sec-butoxymethyl)furan (up to 63% total yield, in 2-butanol at 200°C/24 h). Mechanistic, reaction kinetics and material characterization studies indicated that the catalytic results depend on a complex interplay of different factors (material properties, type of substrate). The recovered-reused solids performed steadily.

Transforming levulinic acid (LA) to γ -valerolactone (GVL) is a significant route for converting biomass into valuable chemicals. The development of an efficient and robust heterogeneous catalyst for this reaction has aroused great interest. In this work, nitrogen-doped graphene (NG) supported nickel (Ni) based heterogeneous catalyst with excellent activities was successfully synthesized. The Ni/NG catalyst shows outstanding performance for hydrogenation of LA to GVL at a relatively low temperature of 140 °C, which is superior to most of reported heterogeneous catalysts. Further investigations indicate Ni nanoparticles are the active sites and the NG also plays an indispensable role. The catalytic performance is highly depended on the crystallinity, particles sizes and electronic structure of Ni in Ni/NG catalyst, which can be optimized by nitrogen doping. This work affords a new route for designing robust and excellent heterogeneous catalysts by doping method to optimize the support. [ABSTRACT FROM AUTHOR]

Cobalt‐catalyzed selective transformation of levulinic acid and primary amines into pyrrolidines and pyrrolidinones under H2 has been developed. The catalyst system consisting of Co(NTf2)2, 1,1,1‐tris(di(4‐methoxyphenyl)phosphinomethyl) ethane ((p‐anisyl)triphos) and Me3SiOTf works well for the synthesis of pyrrolidines via reductive amination/cyclization/deoxygenative reduction of amide, and using Co(NTf2)2/1,1,1‐tris(diphenylphosphinomethyl) ethane (triphos) as the catalyst under reduced hydrogen pressure results in exclusive formation of pyrrolidinones. Both aryl and alkyl primary amines are suitable substrates, and a variety of functional groups are tolerated. Meanwhile, 4‐oxo‐4‐arylbutanoic acids, 5‐oxohexanoic acid, 6‐oxoheptanoic acid, 2‐formylbenzoic acid, 2‐acetylbenzoic acid and 2′‐acetyl‐[1,1′‐biphenyl]‐2‐carboxylic acid are also applicable, allowing for convenient access to cyclic amines and lactams with different ring size. [ABSTRACT FROM AUTHOR]

Breaking down lignin into smaller units is the key to generate high value‐added products. Nevertheless, dissolving this complex plant polyphenol in an environment‐friendly way is often a challenge. Levulinic acid, which is formed during the hydrothermal processing of lignocellulosic biomass, has been shown to efficiently dissolve lignin. Herein, levulinic acid was evaluated as a medium for the reductive electrochemical depolymerization of the lignin macromolecule. Copper was chosen as the electrocatalyst due to the economic feasibility and low activity towards the hydrogen evolution reaction. After depolymerization, high‐resolution mass spectrometry and nuclear magnetic resonance spectroscopy revealed lignin‐derived monomers and dimers. A predominance of aryl ether and phenolic groups was observed. Depolymerized lignin was further evaluated as an anti‐corrosion coating, revealing enhancements on the electrochemical stability of the metal. Via a simple depolymerization process of biomass waste in a biomass‐based solvent, a straightforward approach to produce high value‐added compounds or tailored biobased materials was demonstrated. [ABSTRACT FROM AUTHOR]

Levulinic acid (LA) is one of the top twelve chemicals listed by the US Department of Energy that can be derived from biomass. It serves as a building block and platform chemical for producing a variety of chemicals, fuels and materials which are currently produced in fossil based refineries. LA is a key strategic chemical, as fuel grade chemicals and plastic substitutes can be produced by its catalytic conversion. LA derivatisation to various product streams, such as alkyl levulinates via esterification, γ-valerolactone via hydrogenation and N-substituted pyrrolidones via reductive amination and many other transformations of commercial utility are possible owing to the two oxygen functionalities, namely, carbonyl and carboxyl groups, present within the same substrate. Various biomass feedstock, such as agricultural wastes, marine macroalgae, and fresh water microalgae were successfully converted to LA in high yields. Finding a substitute to mineral acid catalysts for the conversion of biomass to LA is a challenge. The use of an ultrasound technique facilitated the production of promising nano-solid acid catalysts including Ga salt of molybophosphoric acid and Ga deposited mordenite zeolite, with optimum amounts of Lewis and Bronsted acidities needed for the conversion of glucose to LA in high yields, being 56 and 59.9 wt.% respectively. Microwave irradiation technology was successfully utilized for the accelerated production of LA (53 wt.%) from glucose in a short duration of 6 min, making use of the unique synergistic catalytic activity of ZnBr2 and HCl. [ABSTRACT FROM AUTHOR]

Valorization of agri-food residues to produce bio-based platform chemicals will enhance the transition to the bio-economy era. To this end, a sustainable process has been developed for the overall valorization of grape stalks (GS) according to a circular approach, starting from the lignin fraction to further deal with the cellulose-rich residue. This non-conventional protocol fully adheres to green chemistry principles, exploiting the so-called enabling technologies—mainly ultrasound and microwaves—for energy-saving innovative processes. Firstly, ultrasound-assisted extraction (UAE, 40 kHz, 200 W) demonstrated to be an excellent technique for GS delignification combined with natural deep eutectic solvents (NaDESs). Delignification enables isolation of the pertinent lignin framework and the potential to obtain a polyphenol-rich liquid fraction, focusing on the valorization of GS as source of bioactive compounds (BACs). Among the NaDESs employed, the combination of choline chloride (ChCl) and levulinic acid (LevA) (ChLevA) presented noteworthy results, enabling a delignification higher than 70%. LevA is one of the top-value biobased platform chemicals. In this work, a flash microwave (MW)-assisted process was subsequently applied to the cellulose-rich fraction remained after delignification, yielding 85% LevA. The regeneration of this starting compound to produce ChLevA can lead to a further biomass delignification cycle, thus developing a new cascade protocol for a full valorization of GS. [ABSTRACT FROM AUTHOR]

Safe and cost-effective antimicrobial fabrics (e.g., face masks and air filters) are conducive to preventing the spread and transmission of respiratory microorganisms in food processing plants and retail establishments. The objective of this study was to coat fabrics with two commonly used compounds in the food industry: levulinic acid (LVA) and sodium dodecyl sulfate (SDS) and determine the antimicrobial efficacy of the coated fabrics against bacterial solutions, aerosols, and influenza A virus subtype H1N1. In addition, air permeability and shelf-life of the LVA/SDS coated fabrics were also examined. Nonwoven fabrics were dip-coated with three concentrations (w/v, 0.5% LVA + 0.1% SDS, 1% LVA + 0.5% SDS, and 2% LVA + 1% SDS) of LVA and SDS and challenged with bacterial solutions (Staphylococcus aureus and Escherichia coli, ca. 7.0 log CFU/coupon) for a contact time of 3, 5, and 10 min. The coated fabrics were also challenged with S. aureus aerosol and H1N1 virus following standard operations of ASTM F2101-19 and ISO 18184:2019, respectively. The 1% LVA + 0.5% SDS coated fabrics showed potent antibacterial efficacy against both bacterial solutions (>6.0-log reduction to under the detection limit of 1.0 log CFU/coupon for S. aureus; ca. 1.0-log reduction for E. coli) and aerosols (>3.6-log reduction to under the detection limit), with greater inactivation occurring at higher concentrations and longer exposure time. Moreover, the coated fabrics inactivated >99% of the H1N1 virus. The shelf-life of the coated fabrics was stable within 12 months and the air permeability was not adversely affected with the coating concentrations less than 1% LVA + 0.5% SDS. Results reveal these low-cost and safe materials have the potential to be used to coat fabrics in the food industry to combat the spread and transmission of pathogens. [ABSTRACT FROM AUTHOR]

Levulinic acid is a platform chemical. This compound can be derived from conversion cellulose in lignocellulosic biomass such as rice husk. Cellulose conversion to levulinic acid can be enhanced with the help of a catalyst. Hierarchical Mn3O4/ZSM-5 was sed as a catalyst in this study, which was made by wet impregnation of ZSM-5 with Mn (II). Before the conversion reaction, rice husk was pretreated with various chemical and mechanical methods to increase the amount of cellulose. The chemical method used NaOH, while mechanical methods used variations of ball milling and ultrasonication in phosphoric acid. The pretreated rice husk was then converted to levulinic acid at 130°C for 10 h in H3PO4 40% and H2O2 30% using hierarchical Mn3O4/ZSM-5 as a catalyst. The highest levulinic acid yield of 11.70% was obtained from the delignification of rice husk. The product was then extracted to obtain pure levulinic acid via solvent extraction using xylene and ethyl acetate as the organic solvents. The GC-MS examination showed that ethyl acetate is the best solvent and esterification agent in separating the levulinic acid. [ABSTRACT FROM AUTHOR]

Although various hydrometallurgical and solvometallurgical efforts have been made to extract REEs from end-of-life (EoL) products and waste, a systematic and statistical analysis of the impacts of leaching parameters to optimize the leaching process using organic acids is necessary, but lacking in the literature. This study employed the response surface methodology to develop mathematical models for optimal leaching by levulinic acid (LevA) of REEs in two waste materials, namely red mud and spent fluorescent lamp phosphors. The established models exhibited excellent statistical properties, in terms of significance, fitting, prediction, and error distribution. For red mud, the optimal conditions of liquid-to-solid ratio (L/S; v/w) of 40, temperature of 70 °C, and duration of 60 h led to 100% leaching of REEs excluding Sc. At the same L/S and temperature, >98.7% of REEs were leached from fluorescent phosphors after 96 h. The SEM–EDS analysis of the waste materials revealed and confirmed morphological and compositional changes after leaching under the optimal conditions. [ABSTRACT FROM AUTHOR]

Among the various biomass-derived platform chemicals, levulinic acid (LA) has been identified as one of the top-10 important molecules by Department of Energy, United States of America because value-added chemicals such as γ-Valerolactone (GVL), derivatives of valeric acid (VA) can directly be obtained from it. The bare SBA-15 and Sn-SBA-15 mesoporous catalysts with different Si/Sn (25 and 50) molar ratios were prepared by hydrothermal in-situ method and different amounts of Ru loaded samples (x% Ru/Sn-SBA-15 with Si/Sn = 25 where x = 1, 3, 5 and 7% of Ru) were prepared by impregnation method. The structure, phase composition, morphology and surface elemental analysis of as-prepared catalysts were analyzed by various instrumental techniques. The synthesized Ru/Sn-SBA-15 catalysts were subjected to hydrogenation of LA into GVL. Among the different catalysts synthesized, 5% Ru/Sn-SBA-15 catalyst was identified as the most efficient catalyst (99% LA conversion and 98% selectivity towards GVL). The outstanding catalytic performance of the catalyst is attributed to the mesoporous structure, the acidic properties of the support and the interactive effect between Ru and Sn. The recyclability test revealed that the 5% Ru/Sn-SBA-15 catalyst exhibit good stability and reusability. [ABSTRACT FROM AUTHOR]

Herein, the impact of cerium species loaded on mesoporous silica of MCF type on the state and catalytic activity of ruthenium species was studied. Up to 20 wt.% of cerium was incorporated on the silica surface, whereas the same 1 wt.% of Ru loading was applied. The samples prepared were examined by low temperature N2 adsorption/desorption, XRD, XRF, ICP-OES, XPS and H2 chemisorption. The catalytic activity of the materials obtained was investigated in the transformation of levulinic acid to γ-valerolactone. It was documented that the presence of Ce favored an increase in the dispersion of ruthenium species, which had a positive impact on the hydrogenation activity for up to 10 wt.% of Ce. Nevertheless, the highest cerium loading had a negative influence on the textural parameters of the support. [ABSTRACT FROM AUTHOR]

Electrosynthesis offers an efficient and sustainable strategy for the conversion of biomass‐derived platform molecules. Among this process, developing efficient and cost‐effective electrocatalysts is of vital importance. We report herein the preparation of the nanocrystalline PbO‐In2O3 catalysts for the electrocatalytic reduction of levulinic acid (LA) to valeric acid (VA). A series of non‐noble nanocrystalline PbO‐In2O3 composite materials with different molar compositions were prepared and thoroughly characterized. The prepared nanocrystalline PbO‐In2O3 composite materials were used as working electrode for the electrocatalytic hydrogenation of LA in an H‐type electrolytic cell. A LA conversion of 41.4 % and VA selectivity of 97.8 % was achieved with the VA faradic efficiency of 89.2 % under the high current density of 134 mA cm−2. This is the first report on the electrocatalytic reduction of LA to VA using PbO‐In2O3 composite electrode catalyst. [ABSTRACT FROM AUTHOR]

The synthesis of 5‐methyl‐2‐pyrrolidone through reductive amination of levulinic acid (LA) with ammonium formate (AF) as a source of both hydrogen and nitrogen over Pd/C catalyst was investigated. The effects of various reaction parameters, such as solvent, catalyst dosage, ammonium formate amount and temperature on the conversion of LA into 5‐methyl‐2‐pyrrolidone (MPD) were systematically investigated. The results showed that a MPD yield as high as 98 % was obtained in water at 180 °C for 4 h under a low metal content (0.28 mol% Pd relative to LA), which is higher than many previous reports. The Pd/C catalyst could be reused for at least 9 times with only a slight loss in activity. Meanwhile, Pd/C catalyst was efficient for the conversion of LA/ester into various N‐substituted‐5‐methyl‐2‐pyrrolidones (80–93 % yield) by using a mixture of formic acid and the corresponding primary amines. [ABSTRACT FROM AUTHOR]

The reductive amination of biomass‐derived levulinic acid (LA) to value‐added N‐substituted pyrrolidinones with amine and molecular hydrogen over heterogeneous catalyst represents an atom‐economical and scalable route. In this paper, a series of boron doped Cu/Al2O3 catalysts via kneading and impregnation method are developed for the continuous reductive amination of LA. Compared with Cu/Al2O3, Cu10/AlB3O catalyst exhibits greatly improved catalytic performance for this reaction at low operation temperature. Structure‐property correlation investigations were performed with diverse characterization methods, and the results revealed that the excellent catalytic performance of boron doped Cu/Al2O3 catalysts was mainly attributed to the synergistic effect of its well‐dispersed Cu nanoparticles, appropriate surface Cu electronic state and surface acidic sites nearby. Besides, Cu10/AlB3O shows great stability during the reaction over 200 h. This work provides a low‐cost, efficient and environmentally friendly heterogeneous catalytic system for the continuous production of N‐substituted pyrrolidinones. [ABSTRACT FROM AUTHOR]

5‐hydroxymethylfurfural (HMF) is one of the most valuable biomass platform molecules, enabling the construction of a plethora of high value‐added furanic compounds. In particular, in the last decade, HMF has been considered as a starting material for designing biobased surfactants, not only because of its renewability and carbon footprint, but also because of its enhanced biodegradability. This Review presents recent examples of the different approaches to link the hydrophilic and lipophilic moieties into the hydrophobic furan (and tetrahydrofuran) ring, giving a variety of biobased surfactants that have been classified here according to the charge of the head polar group. Moreover, strategies for the synthesis of different non‐furanic structures surfactant molecules (such as levulinic acid, cyclopentanols, and aromatics) derived from HMF are described. The new HMF‐based amphiphilic molecules presented here cover a wide range of hydrophilic‐lipophilic balance values and have suitable surfactant properties such as surface tension activity and critical micelle concentration, to be an important alternative for the replacement of non‐sustainable surfactants. [ABSTRACT FROM AUTHOR]

Levulinic acid is considered among the top twelve chemicals from biomass in terms of market potential, due to its considerable number of applications. Levulinic acid is obtained by acid hydrolysis of glucose using dilute sulfuric acid as a catalyst. Because of this, the resulting stream has an excess of water, which has an impact on energy consumption in the separation and purification process. So, it is important to analyze sustainable alternatives. Process intensification can help achieve this goal. Particularly, reactive distillation (RD) is an intensified process where is carried out the chemical reaction and distillation in a single equipment, the advantage of this reduction has a direct impact on the capital cost, and energy consumption in the last stages of separation. and environmental impact, improving the sustainability of the process. Additionally, reactive distillation positively impacts performance, and it is used to separate dilute mixtures more efficiently. Therefore, this work's objective is to implement a process intensification using a reactive distillation column to reduce energy consumption, process costs, and the final cost of Levulinic acid production. A conventional scheme is used to compare the energy, cost, environmental, and conversion impacts when using reactive distillation. The results show a total conversion of glucose to Levulinic acid using RD and similar purities are obtained when using the conventional reactor. In addition, it presents savings in the cost of the equipment by 23% and 24% in energy consumption compared to the conventional system. [Display omitted] • Synthesis and Design of alternatives to produce and purify levulinic acid. • Feasibility of using reactive distillation to produce and purify levulinic acid. • Optimization Process considering energy consumption. • Use of metrics to assess the sustainability of the process [ABSTRACT FROM AUTHOR]

An active and stable Co catalyst decorated by N species was developed and applied in the hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL). The catalyst was first synthesized by grafting glucose (G) and melamine (M) on cobalt phyllosilicate (CoPS) hydrothermally, and then by pyrolyzing GM/CoPS at a designated temperature for the carbothermal reduction (denoting as GM@CoPS-X; X = temperature). Among tested catalysts, GM@CoPS-700 showed the most promising GVL productivity (1684 mmol GVL/gsurface Co /h), stability, and recyclability (an ca. 8% loss of initial activity) in five consecutive trials. Doped N species were found to improve the concentration of Coδ+ (0 < δ < 2) with a strong Lewis acidity. The synergy of Coδ+ and Co0 was the key in enhancing the activity of Co-based catalysts derived from CoPS. [ABSTRACT FROM AUTHOR]

Non‐renewable resources have adverse effects on the environment, which result in global warming. Research has been shifted toward sustainable resources and lignocellulosic biomass is the best example of this. Lignocellulosic biomass is inexpensive, abundantly available and a rich source of carbon, which makes society less dependant on the use of fossil fuels. It is necessary for society to stop using petroleum‐based technologies and start developing more biomass‐based technologies. Lignocellulosic biomass can be converted into levulinic acid through various methods. Various value‐added chemicals are synthesized from levulinic acid, such as levulinate esters, acrylic acid, β‐acetyl acrylic acid, 1,4‐pentanediol, 2‐methyl tetrahydrofuran, γ‐valerolactone, etc. Among these, levulinate esters have received much attention owing to their broad applications as fuel additives, plasticizers and solvents in the pharmaceutical industries. Levulinate esters can be synthesized from the esterification reaction of levulinic acid and alcohol in the presence of either liquid or solid acid catalysts. Heterogeneous catalysts are favoured above homogeneous catalysts because of their properties, like being easy to separate, having good catalytic activity, being non‐corrosive to the reactor and having good recyclability. The performance of various heterogeneous catalysts such as zirconia, heteropolyacids, zeolite, carbonaceous material, resins and biocatalysts is reported in detail in the review. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]

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Converting levulinic acid (LA) to fuel precursors such as gama-valerolactone (GVL) and valeric acid (VA) via an efficient and low-cost method is of great significance. Herein, a series of free-standing electrodes consisting of metallic metals supported by carbon felts (CFs) were fabricated via a facile electro-deposition process. The resulting M/CFs (M = Pb, Cd, Co, Ni, Cu and Bi) electrodes were evaluated for electrocatalytic hydrogenation (ECH) of LA. The electrocatalytic activity of the electrodes was extensively studied by various electrochemical methods including cyclic voltammetry, linear sweep voltammetry and chronoamperometry measurements. The products of the ECH processes were analyzed by gas chromatography-mass spectrometry. Of all the prepared samples, the Pb/CFs and Cd/CFs electrodes showed superior performance for ECH of LA. The selectivity of VA reached up to 91.7% when the Pb/CFs was used and the conversion of LA reached to 57.2% using the Cd/CFs electrode, rendering them as one of the best electrodes for ECH reported in the literature. The effects of applied potentials on the ECH process were investigated. To further optimize the ECH performance of the Pb/CFs electrodes, several key parameters including deposition time, pH value of the electrolyte and reaction time were studied. When the electrodeposition time was 600 s and the concentration of sulfuric acid in the electrolyte was 0.5 M, the complete transformation of 0.2 M of LA was achieved after 6 h. This study may afford an alternative way to the conversion of LA to GVL or VA. [Display omitted] • Self-standing M/CFs (M = Pb, Cd, Co, Cu, Ni and Bi) electrodes were studied for ECH of LA. • The Pb/CFs and Cd/CFs showed superior performance on activity and product selectivity. • The applied potentials affected the product distribution of the ECH processes. • The Pb/CFs exhibited the largest VA selectivity of 91.7%. • The effects of deposition time, pH value of the electrolyte and reaction time were explored. [ABSTRACT FROM AUTHOR]

γ-Valerolactone (GVL) has been considered an alternative as biofuel in the production of carbon-based chemicals; however, the use of noble metals and corrosive solvents has been a problem. In this work, Ni supported nanocatalysts were prepared to produce γ-Valerolactone from levulinic acid using methanol as solvent at a temperature of 170 °C utilizing 4 MPa of H2. Supports were modified at pH 3 using acetic acid (CH3COOH) and pH 9 using ammonium hydroxide (NH4OH) with different tungsten (W) loadings (1%, 3%, and 5%) by the Sol-gel method. Ni was deposited by the suspension impregnation method. The catalysts were characterized by various techniques including XRD, N2 physisorption, UV-Vis, SEM, TEM, XPS, H2-TPR, and Pyridine FTIR. Based on the study of acidity and activity relation, Ni dispersion due to the Lewis acid sites contributed by W at pH 9, producing nanoparticles smaller than 10 nm of Ni, and could be responsible for the high esterification activity of levulinic acid (LA) to Methyl levulinate being more selective to catalytic hydrogenation. Products and by-products were analyzed by 1H NMR. Optimum catalytic activity was obtained with 5% W at pH 9, with 80% yield after 24 h of reaction. The higher catalytic activity was attributed to the particle size and the amount of Lewis acid sites generated by modifying the pH of synthesis and the amount of W in the support due to the spillover effect. [ABSTRACT FROM AUTHOR]

Lignocellulosic material represents an attractive raw material to the synthesis of different compounds with industrial interest. Among these compounds, levulinic acid has gained considerable attention. Nonetheless, the difficulty of separating it from the aqueous media and the low yield often obtained in its synthesis hinder its commercial production. The liquid-liquid extraction process can be an effective approach to overcome these limitations. The transfer of the levulinic acid from the aqueous medium to an organic phase avoids the contact of the acid with the catalyst, minimizing side reactions and simplifying the subsequent separation process. For this purpose, the solvent choice is of utmost importance. This work aimed to identify potential solvents for the extraction of levulinic acid from the aqueous medium. An initial screening was conducted using the COSMO-SAC model to estimate partition coefficients of levulinic acid in thirty different organic solvents. The highest partition of levulinic acid in the organic phase was calculated for 2-tert-butylphenol, MIBK and 2-heptanone. However, experimental data obtained for these systems showed that the model overestimated the partition coefficient values. The mutual solubilities between the two phases shift the activity of levulinic acid in the aqueous phase, which made the predictions inaccurate. [ABSTRACT FROM AUTHOR]

Levulinic acid, a versatile chemical building block, was derived from C6-sugar galactose using sulfuric acid as the catalyst. Galactose is monosaccharide of polysaccharides constituent that is mostly contained in third generation biomass, macro-microalgae. It currently receives high attention to be a source of renewable feedstock. The effect of temperature, catalyst concentration and initial substrate loadings were studied for 60 min, in the temperature range of 150-190 °C, acid concentration of 0.25-0.75 M and initial substrate loading of 0.05-0.25 M. The highest levulinic acid yield of 40.08 wt% was achieved under the following conditions: 0.05 M galactose, 0.75 M acid concentration, 170 °C temperature, and 40 min reaction time. The kinetic model was developed by first order pseudoirreversible reaction. The results showed that the proposed model could capture the experimental data well. These results suggested that galactose, derived from macro- and micro-algae, can potentially be converted and applied for platform chemicals. [ABSTRACT FROM AUTHOR]