Production Of Methyl Levulinate Research Articles

Improved production of methyl levulinate from catalytic conversion of cellulose over cobalt sulfide by nickel doping

Transition metal sulfides have rich Brønsted/Lewis's acid sites and various metal valence states, which have great influence on their catalytic performance. In this study, the nickel cobalt sulfides with different molar ratios of Ni to Co were synthesized by one-step solvothermal method for the highly efficient catalytic conversion of cellulose into methyl levulinate (ML). Interestingly, with the continuous incorporation of Ni, the catalytic efficiency of the catalysts increased first and then decreased. It was worth mentioning that when the ratio of Co/Ni is 1, the ML yield was the highest (39.6 wt%), much higher than CoS2 and NiS2 (30.5 and 30.1 wt%, respectively). Based on the characterization of the prepared catalysts, it was found that the improved catalytic performance of Ni0.50Co0.50S2 was potentially due to the synergistic effect of lower Co3+/Co2+ ratio and larger Ni3+/Ni2+ ratio. Furthermore, the Ni0.50Co0.50S2 catalyst had a great recycling performance, which still maintained 78% of the initial catalytic efficiency after reused for 5 times.

Carbon footprint analysis of supply chain of bio-based methyl levulinate production in China

The carbon reduction effect of bio-based levulinic acid chemicals is a matter of concern. This work reports the life cycle assessment of methyl levulinate based on local biomass refineries in China. The final LCA results showed that the entire life cycle of methyl levulinate could reduce by approximately 24% of carbon emissions compared with fossil diesel of equal quality. To address the lack of effective uncertainty analysis in current LCA research on levulinic acid chemicals, this study conducted a comprehensive and detailed assessment of inventory data and utilized Taylor series expansion to obtain uncertainty of the LCA results. When connected to a localized background database, the LCA results showed high credibility. According to the sensitivity analysis and Aspen optimization results, further technical improvement schemes are proposed, including improving thermal efficiency, use of clean electricity, and use of clean methanol. Prospective analysis shows that combined implementation of the above strategies can further reduce the existing carbon emissions by more than half.Graphical

Assessment of the thermal degradation kinetics of fresh green coconut husk (Cocos nucifera L.) powder and after methyl levulinate production

Assessment of the thermal degradation kinetics of fresh green coconut husk (Cocos nucifera L.) powder and after methyl levulinate production

Assessment of the thermal degradation kinetics of fresh green coconut husk (Cocos nucifera L.) powder and after methyl levulinate production

This study describes the recycling of green coconut husk powder (CHP) aimed at the sustainable production of methyl levulinate. The preliminary step involved thermogravimetric analysis of green (CHP) and residues after synthesis of methyl levulinate with the catalyst’s aluminum sulfate (CHP-AS) and titanium dioxide (CHP-TD), based on a degradation and determination of activation energy using the Ozawa-Flynn-Wall (OWF) method. Thermogravimetric analyses showed significant differences between the main constituents of CHP, CHP-AS and CHP-TD residues: hemicellulose (18.18, 9.78 and 12.17%), cellulose (44.65, 26.18 and 44.23%) and lignin (20.09, 19.89 and 19.58%), respectively. The methyl levulinate concentration obtained by the reaction between CHP and aluminum sulfate was 16.53 g.L-1, due to the participation of hemicellulose and cellulose. The results showed that the activation energies calculated using the OFW method were 142 kJ.mol-1 (CHP), 125 kJ.mol-1 (CHP-AS) and 180 kJ.mol-1 (CHP-TD).

Green solvent system for isolation of biopolymers from Mentha arvensis distilled biomass and saccharification to glucose for the production of methyl levulinate

Cornmint (Mentha arvensis) is cultivated to produce essential oil, which consists of about 75% of menthol. Fresh biomass is hydrodistilled for ∼5 h to obtain essential oil (1%), and the rest of the pre-treated biomass (99%) is generated as waste. A novel, green and economical two-step process has been developed using a mixture of imidazole (IM:1 M)-p-toluene sulfonic acid (pTSA:1.2 M), and IM (0.2 M)-20%NH3 for the separation of lignin and hemicellulose, respectively. The lignin and hemicellulose were isolated from the respective solution by precipitation, and final undissolved solid residue was obtained as cellulose. This process was scaled-up, recovering cellulose (38%), hemicellulose (27%), and lignin (14%) using 7 L double jacketed reactor. The processing parameters such as temperature, solvent ratio, and time were optimized using single factorial design mathematical model for the isolation of biopolymers. Further, cellulose was enzymatically biotransformed to glucose through submerged and solid-state fermentation (SSF) using Trichoderma reesei, T. harzianum (TH, TH10), and T. atroviride. Isolated cellulose was produced 61.5% of glucose at 30 °C, pH 5 in 72 h through SSF process using TH10 strain. This glucose solution was transformed to methyl levulinate (74%) under aqueous-methanol (5:1) solvent system for 2 h at 160 °C using La(OTf)3.H2O catalyst.

Production of methyl levulinate from cellulose over cobalt disulfide: The importance of the crystal facet (111)

The conversion of cellulose to platform chemicals has attracted much attention because of its renewability. This work proposed an earth-abundant cobalt disulfide as a heterogeneous catalyst for methyl levulinate production from cellulose. The highest yield of methyl levulinate reached 61 mol% under the tested conditions of 200 °C, 2 MPa initial pressure, 0.45 catalyst/cellulose mass ratio, and 3 h reaction time. The XRD and TEM analyses demonstrated the crystal facet (111) of cobalt disulfide as a robust active site, which was in good agreement with the highest acidity of the crystal facet (111) calculated by the work functions. The XPS characterization showed that the main chemical valence of cobalt disulfide responsible for the methyl levulinate production was the surface Co2+ species. This study is valuable for the development of a recoverable catalyst for the cellulose to methyl levulinate process.

Green Solvent System for Isolation of Biopolymers from Mentha Arvensis Distilled Biomass and Saccharification to Glucose for the Production of Methyl Levulinate

Green Solvent System for Isolation of Biopolymers from Mentha Arvensis Distilled Biomass and Saccharification to Glucose for the Production of Methyl Levulinate

The effect of enzyme loading, alcohol/acid ratio and temperature on the enzymatic esterification of levulinic acid with methanol for methyl levulinate production: a kinetic study.

As an important bio-based chemical, methyl levulinate (ML) can be produced via enzymatic esterification of levulinic acid with methanol. A kinetic model is developed in this work based on the law of mass action and reaction reversibility, to investigate the effect of enzyme loading, alcohol/acid ratio and temperature on ML yield. Data analysis shows that newly developed binary regression is apparently more persuasive than the commonly used unitary regression. Kinetic study reveals: (1) rate constants of esterification/hydrolysis increase with increasing enzyme loading, while their ratio (equilibrium constant) remains invariant. (2) Methanol has no toxicity towards lipase, and hence, neither the rate constants of esterification/hydrolysis nor the equilibrium constant are affected by alcohol/acid ratio. (3) Both rate constants of esterification/hydrolysis and the equilibrium constant increase with temperature elevation, and their relationships agree with Arrhenius equation and Van't Hoff equation, respectively. (4) The esterification is endothermic and spontaneous. In total, the application of binary regression analysis for the developed model to study the enzymatic esterification kinetics is quite successful.

Sustainable production of methyl levulinate from biomass in ionic liquid-methanol system with biomass-based catalyst

The preparation of bifunctional solid-acid catalyst and production of methyl levulinate were performed synergistically based on the fractionation of wood residue. The hydrothermal hydrolysate of wood residue was utilized for catalyst preparation using template method with sulfonic group as the Brønsted acid site and Zr4+ as Lewis acid site. Cellulose material for methyl levulinate production was fractionated by the delignification of hydrothermal residue using deep eutectic solvent. In this study, yield of methyl levulinate reached 38.7% under the optimized experiment condition. Insight gained from this work suggests a sustainable strategy for methyl levulinate production using recyclable biomass-based catalyst in ionic liquid-methanol system.

Efficient conversion of cellulose to methyl levulinate over heteropoly acid promoted by Sn-Beta zeolite

One-pot conversion of cellulose to valued-added platform chemicals such as alkyl levulinate is a promising and challenging process of biomass utilization due to the insolubility of cellulose in alcohol. In this work, commercial heteropoly acid combined with postsynthesized Sn-Beta zeolite was employed to transform cellulose to methyl levulinate (MLE) in one pot. The synergistic catalysis of the homogeneous strong Bronsted (B) acid and the solid strong Lewis (L) acid can effectively realize the depolymerization of solid cellulose and the subsequent isomerization, dehydration and hydration steps to MLE. 55% and 62% of MLE yields were obtained from α-cellulose and microcrystalline cellulose, respectively, at 160 °C for 10 h. Various carbohydrates besides cellulose can also be efficiently converted to MLE in high yields over the bifunctional catalyst system. The effects of the amount of B acid and L acid, the reaction temperature and time and the amount of cellulose on the production of MLE were investigated in detail. Finally, the reaction pathway of cellulose to MLE was revealed. Recyclability tests indicated that the binary catalyst can be reused without decrease of catalytic activity.

Direct conversion of furan into levulinate esters via acid catalysis

This study developed a method for the direct conversion of the biomass-derived furan to the methyl levulinate, a platform molecule, via acid-catalysis in dimethoxymethane/methanol. Dimethoxymethane acted as the electrophile to transform furan into 2-methoxymethyl-furan (the ether of furfuryl alcohol). The following step of acid catalysis converted 2-methoxymethyl-furan to methyl levulinate. No hydrogenation catalyst or hydrogen was used in the process, which was the new reaction route for the conversion of furan to the value-added levulinic acid/ester. Polymerization was the main challenge in this reaction route, which could be suppressed but to some limited extent with methanol as a co-reactant/solvent in the reaction medium. The polymerization of furan and cross-polymerization reactions between dimethoxymethane (the reactant) and methyl levulinate (the targeting product) via Aldol condensation were the important reasons for the decreased production of methyl levulinate. The DRIFTS and TG-MS studies showed that the coke formed from the polymerization of furan contained more aliphatic structure, more carboxylic groups and methyl groups, while the coke from methyl levulinate contained more carbonyl groups and more conjugated π-bonds, projecting the structural difference of furan and methyl levulinate.

First triple-functional polyoxometalate Cs10.6[H2.4GeNb13O41] for highly selective production of methyl levulinate directly from cellulose

The first triple-functional polyoxometalate Cs10.6[H2.4GeNb13O41] (CsGeNb) was evaluated for its catalytic activity in production of methyl levulinate (ML) from biomass substrates in methanol. Higher conversion of cellulose (86.0%) and higher yield of ML (53.0%) were obtained under optimized reaction conditions of 0.1 g of cellulose, 0.04 mmol of catalyst, and 6 mL of methanol at 165 °C for 10 h, due to its mixed Bronsted acid sites, Lewis acid sites, and base sites, being measured for the first time. Reaction intermediates in methanolysis of fructose, glucose, and cellulose provided some insight into the reaction pathways, while methyl glucoside and methyl fructoside (MF) were key intermediates generated by Bronsted acid and Lewis acid or base sites. Assisted by microwave irradiation, the efficiency could be improved to 55.4% yield of ML within 3 h. Meanwhile, CsGeNb acted as a heterogeneous catalyst through six recycles without loss of activity.

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.

Efficient conversion of wheat straw into methyl levulinate catalyzed by cheap metal sulfate in a biorefinery concept

Wheat straw can be converted into biofuel candidate-methyl levulinate with copper sulfate as the cheap catalyst. To take advantage of the whole components of wheat straw, a two-stage pretreatment process was developed in this study. In the first-stage process, the hemicellulose component in wheat straw can be converted into biosurfactant at the mild conditions, and the lignin component can be extracted as another value added by-product in the second stage. On the basis, the pretreated wheat straw was used as raw material for methyl levulinate production, and a yield of 20.2 wt% can be obtained under the optimum reaction conditions. Meanwhile, the catalyst recycling experiments showed that copper sulfate was stable and can be reused more than five times. The results of mass balances and preliminary economic analysis further indicated that the production of integrated biorefinery processes producing diversified products offers potential for the sustainable valorization of wheat straw.

Catalyzing Cascade Production of Methyl Levulinate from Polysaccharides Using Heteropolyacids HnPW11MO39with Brønsted/Lewis Acidic Sites

A series of Lewis acid metals monosubstituted phosphotungstic acids HnPW11MO39 (HPWM, M = CuII, ZnII, CrIII, FeIII, SnIV, TiIV, and ZrIV; for Ti and Zr, the number of oxygen is 40) was evaluated in direct production of methyl levulinate (ML) from cellulosic biomass in a cascade reaction. One of the solid catalysts, H5PW11TiO40 (HPWTi), was found to be highly efficient for generation of ML from mono- or polysaccharides, reaching 51.3% ML yield directly from cellulose. And under microwave-assistance, the efficiency could be improved to a 62.6% ML yield within 2 h, which was almost the best result so far among reported solid catalysts. Identification of the reaction intermediates and the products provided some insight into the reaction mechanism and showed the requirement of certain Bronsted/Lewis acid ratio as 2.84/1 for HPWM. Moreover, the different metals in catalysts profoundly affected the Lewis or total acidity, and therefore, the catalytic activity and selectivity to ML or methyl glucosides (MG). HPWT...

Catalysis performance comparison of a Brønsted acid H2SO4 and a Lewis acid Al2(SO4)3 in methyl levulinate production from biomass carbohydrates

An experimental investigation was conducted to understand the roles of the Brønsted acid H2SO4 and Lewis acid Al2(SO4)3 in methyl levulinate (ML) production from biomass carbohydrates, including glucose, fructose and cellulose. The product distributions with different catalysts revealed that the Lewis acid was responsible for the isomerization of methyl glucoside (MG), producing a significant amount of the subsequent product 5-methoxymethylfurfural (MMF), while the Brønsted acid facilitated the production of ML from MMF. Al2(SO4)3 was efficient for monosaccharide conversion but not for cellulose. Using ball-milled cellulose with Al2(SO4)3 resulted in a desired ML yield within a reasonable reaction time. The significant catalysis performances of two types of acids will guide the design of efficient catalytic processes for the selective conversion of biomass into levulinate esters.

Development of New Carbon Resources: Production of Important Chemicals from Algal Residue

Algal biomass has received attention as an alternative carbon resource owing not only to its high oil production efficiency but also, unlike corn starch, to its lack of demand in foods. However, algal residue is commonly discarded after the abstraction of oil. The utilization of the residue to produce chemicals will therefore increase the value of using algal biomass instead of fossil fuels. Here, we report the use of algal residue as a new carbon resource to produce important chemicals. The application of different homogeneous catalysts leads to the selective production of methyl levulinate or methyl lactate. These results demonstrate the successful development of new carbon resources as a solution for the depletion of fossil fuels.

Production of methyl levulinate from cellulose: selectivity and mechanism study

An efficient and environmentally friendly catalytic process for the production of methyl levulinate through cellulose alcoholysis was developed. The formation of methyl levulinate follows the sequence: cellulose → methyl glucoside → 5-MMF → methyl levulinate, and Brönsted acid played a key role in its high selectivity.

Acid-Catalyzed Direct Synthesis of Methyl Levulinate from Paper Sludge in Methanol Medium

A direct synthesis of methyl levulinate from the degradation of paper sludge in a methanol medium at moderate temperatures (≤ 230 °C) was performed using low-concentration sulfuric acid (≤ 0.05 mol/L) as the catalyst. Response surface methodology with a four-factor, five-level central composite rotatable design was employed to optimize the process conditions for maximized methyl levulinate production under the condition of controlling the dehydration of methanol to dimethyl ether. The yields of methyl levulinate and dimethyl ether as a function of the process variables were fitted to second-order polynomial models through application of multiple regression analyses. A good agreement between the experimental and modeled data was obtained. When the controlled yield of dimethyl ether was less than 20%, a maximum methyl levulinate yield of 54.8% was achieved, corresponding to 27.7% (w/w) overall yield for dry paper sludge. The findings indicated that paper sludge can act as a potential biomass material for upgrading and converting into high value-added chemicals.

Effects of Zr/Ti molar ratio in SO2−4/ZrO2-TiO2 calcined at different temperatures on its surface properties and glucose reactivity in near-critical methanol

Effects of Zr/Ti molar ratio in SO2−4/ZrO2-TiO2 solid acid catalyst calcined at different temperatures on its surface properties and catalytic activity were thoroughly investigated in this paper. The physicochemical characteristics of prepared samples were determined by N2 adsorptiondesorption, XRD, NH3-TPD and XPS techniques, respectively. It was found that the crystallization temperature of the samples increased after the combination of ZrO2 and TiO2; and phase transformations from the anatase to the rutile of TiO2 species and the tetragonal to the monoclinic of ZrO2 species were effectively suppressed at higher temperature. The sample with a Zr/Ti molar ratio of 3/1 calcined at 450 °C showed the highest surface area and the most acid sites among all the tested samples. The acid site densities of samples were relatively closed to each other if they were calcined at the same temperature, however, decreased with the calcination temperature. The result indicates that the sulfur content in samples is a crucial factor to control the acid site density. Calcining the sample at 650 °C and higher temperatures resulted in a significant desorption of sulfate ion on the samples. The synthesized samples were evaluated as a potential catalyst for glucose conversion under the near-critical methanol conditions (200 °C/4 MPa). The results suggested that the relatively weaker acid sites of the catalyst were more favorable for the accumulation of methyl glucosides, while the moderate acid sites were responsible for the formation of methyl levulinate. The catalytic activity for methyl levulinate production almost increases linearly with the catalyst acid site density. The catalyst deactivation is due to the loss of sulfate ion and the two catalysts with Zr/Ti molar ratios of 3/1 and 1/3 could effectively alleviate the deactivation caused by sulfate solution in the reaction medium and can be reused after calcination with the reuse rate of over 90% in terms of the methyl levulinate selectivity.