Renewable Levulinic Acid Research Articles

Insights into the influence of feed impurities on catalytic performance in the solvent-free dimerization of renewable levulinic acid

Bio-jet fuel precursors can be produced from the solvent-free aldol dimerization of levulinic acid. The influence of the most common impurities accompanying the levulinic acid produced in lignocellulosic biorefineries (sulfuric acid, water, formic acid, and furfural) has been studied on the catalytic performance of different kinds of heterogeneous acid catalysts: (i) sulfonic acid-based materials, such as propyl-sulfonic acid-modified SBA-15, and the sulfonic acid resin Amberlyst-70, and (ii) commercial acid zeolites, such as H-Beta-19 and H-Beta-75. Furfural is the impurity that produces the greatest detrimental effect on the performances of all the catalysts tested. Catalyst deactivation is observed due to the formation of organic deposits on the catalyst surface (identified by TGA and acid-base titration), phenomenon that is accentuated when furfural is present in the reaction medium. Amberlyst-70 can recover almost totally the initial catalytic activity with a regeneration step based on washing with an acid solution under reflux. For Beta zeolites, the original activity of the catalyst can be easily and totally recovered through a regeneration process by calcination. H-Beta-19 zeolite is shown as the most suitable catalyst for the aldol dimerization of renewable LA, as its activity is not significantly affected by the presence of most of the impurities in the levels herein analyzed. In addition, a simultaneous mixture of all the impurities produces a synergistic effect, even improving the initial activity of the H-Beta-19 zeolite as a consequence of the sulfuric acid contribution to the catalytic effect.

A Review on Alkyl Levulinates Synthesis from Renewable Levulinic Acid using Various Modified Carbon-Based Catalysts

A Review on Alkyl Levulinates Synthesis from Renewable Levulinic Acid using Various Modified Carbon-Based Catalysts

Beta zeolite as an efficient catalyst for the synthesis of diphenolic acid (DPA) from renewable levulinic acid

The solvent-free production of diphenolic acid (DPA) from levulinic acid (LA) and phenol is studied using readily accessible commercial acid zeolites like Beta, ZSM-5 and USY. Acid zeolites are cost-effective catalysts, and they are herein benchmarked against the sulfonic acid resins Amberlyst-15 and Nafion®, and sulfonic acid-functionalized SBA-15 silicas. Beta zeolite with a moderate aluminum content (H-Beta 19, Si/Al=23) presents the best catalytic performance, owing to the right combination of the shape selectivity effect conferred by the BEA structure, and the adequate balance of acidity (Al content and speciation). The optimization of the reaction conditions is tackled by the response surface methodology using as optimization factors the temperature, the PhOH:LA molar ratio, and the catalyst loading. Thus, under the optimized reaction conditions (12 mmol LA, 140 ᵒC, 0.30 g catalyst loading, PhOH:LA = 6:1 mol), over 70% yield to DPA with LA conversion around 77% is obtained after 72 h. Despite the catalyst shows a progressive activity decay in successive uses because of fouling, removal of the formed organic deposits by calcination in air allows restoring the starting catalytic performance.

Hybrid catalyst with combined Lewis and Brønsted acidity based on ZrIV substituted polyoxometalate grafted on mesoporous MCM-41 silica for esterification of renewable levulinic acid

Materials which synergistically combine Lewis and Brønsted acid properties hold potential for applications as efficient heterogeneous catalysts for preparation of biofuels and biolubricants. Herein we report new heterogeneous catalysts based on grafting the intact Lewis metal (ZrIV) substituted Keggin polyoxometalate (POM) on mesoporous silica support. A new approach for immobilization of the POM in MCM-41 silica was developed by co-condensation of Si source (tetraethyl orthosilicate, TEOS) with POM salt in the presence of a template molecule as an alternative to the commonly used acidic POM form and impregnation procedure for catalyst preparation. The proposed synthesis method in combination with extraction of the template proceeded with preservation of the intact POM structure and resulted in hybrid catalysts with in situ generated Brønsted acid sites in addition to the Lewis acidity provided by the metal centers. Textural properties of the catalysts were characterized by X-ray diffraction, N2 physisorption and transmission electron microscopy (TEM). Insight into POM stability and structural transformations during synthesis, template removal and impregnation was provided by solid state 31P and 29Si NMR spectroscopy. Catalytic activity was studied in esterification reactions of levulinic acid with ethanol or octanol to value-added esters. The directly synthesized POM-functionalized hybrid catalysts exceeded the post synthesis impregnated ones, demonstrating significantly higher catalytic activity, recyclability and resistance against leaching. The proposed approach for immobilization of Lewis metal POMs in MCM-41 silica framework with in situ generation of the active Brønsted acid sites opens prospects for the development of efficient hybrid catalysts for esterification reaction, which overcomes the main limitations of common POM based catalysts such as low stability of the acid sites during the synthesis and the catalytic reaction, low surface area, agglomeration of the catalytically active phase and low stability of the Lewis metal center in presence of water.

Catalytic Hydrogenation of Renewable Levulinic Acid to γ-Valerolactone: Insights into the Influence of Feed Impurities on Catalyst Performance in Batch and Flow Reactors

γ-Valerolactone (GVL) is readily obtained by the hydrogenation of levulinic acid (LA) and is considered a sustainable platform chemical for the production of biobased chemicals. Herein, the performance and stability of Ru-based catalysts (1 wt % Ru) supported on TiO2 (P25) and ZrO2 (monoclinic) for LA hydrogenation to GVL is investigated in the liquid phase in batch and continuous-flow reactors using water and dioxane as solvents. Particular attention is paid to the influence of possible impurities in the LA feed on catalyst performance for LA hydrogenation. Benchmark continuous-flow experiments at extended times on-stream showed that the deactivation profiles are distinctly different for both solvents. In dioxane, the Ru/ZrO2 catalyst is clearly more stable than Ru/TiO2, whereas the latter is slightly more stable in water. Detailed characterization studies on spent catalysts after long run times showed that the deactivation of Ru/TiO2 is strongly linked to the reduction of a significant amount of Ti4+ species of the support to Ti3+ and a decrease in the specific surface area of the support in comparison to the fresh catalyst. Ru/ZrO2 showed no signs of support reduction and displayed morphological and structural stability; however, some deposition of carbonaceous material is observed. Impurities in the LA feed such as HCOOH, H2SO4, furfural (FFR), 5-hydroxymethylfurfural (HMF), humins, and sulfur-containing amino acids impacted the catalyst performance differently. The results reveal a rapid yet reversible loss of activity for both catalysts upon HCOOH addition to LA, attributed to its preferential adsorption on Ru sites and possible CO poisoning. A more gradual drop in activity is found when cofeeding HMF, FFR, and humins for both solvents. The presence of H2SO4, cysteine, and methionine all resulted in the irreversible deactivation of the Ru catalysts. The results obtained provide new insights into the (ir)reversible (in)sensitivity of Ru-based hydrogenation catalysts to potential impurities in LA feeds, which is essential knowledge for next-generation catalyst development.

Highly Efficient Conversion of Renewable Levulinic Acid to n-Butyl Levulinate Catalyzed by Sulfonated Magnetic Titanium Dioxide Nanotubes

A new solid acid catalyst Fe3O4@TNTs-SO3H was successfully prepared, characterized, and applied for efficient conversion of renewable levulinic acid to n-butyl levulinate, serving as a promising liquid fuel additive. This catalyst was demonstrated to show high catalytic activity and afford n-butyl levulinate with a yield of 94.6% under optimum conditions.

Catalytic Upgrading of Renewable Levulinic Acid to Levulinate Esters Using Perchloric Acid Decorated Nanoporous Silica Gels

AbstractCatalytic upgrading of renewable biomass resource toward useful chemicals is interesting but challenged, in this paper, several inorganic acids were examined for the catalytic esterification of levulinic acid with alcohol, and then ulteriorly loaded on the applicable supports to obtain the heterogeneous catalysts. Among them, HClO4/SiO2 nanoporous solid‐acid catalyst exhibits the highest catalytic activity for the synthesis of ethyl levulinate. The resulting HClO4/SiO2 catalyst was characterized by FT‐IR, Energy Dispersive X‐ray (EDX)‐mapping, X‐ray Diffraction (XRD), NH3‐Temperature‐Programmed‐Desorption (TPD), and N2 desorption. Various reaction factors including loading of HClO4, catalyst dosage, reaction time and temperature were checked and optimized. As expected, the targeted catalyst affords 99% yield of ethyl levulinate and a durable activity even with five runs. Finally, esterification of levulinic acid with various alcohols over the HClO4/SiO2 was further expanded based on the optimal reaction condition.

A novel bio-based AB2monomer for preparing hyperbranched polyamides derived from levulinic acid and furfurylamine

A new AB2type bio-based monomer (FDA-E) with two amino functional groups and one ester functional group was prepared from renewable levulinic acid and furfurylamine using a three-step reaction.

Sustainable valorization of lignin with levulinic acid and its application in polyimine thermosets

Valorization of lignin with renewable levulinic acid incorporated active ketone groups and could be utilized to produce high-performance polymers.

Formic acid as a hydrogen source for the iridium-catalyzed reductive amination of levulinic acid and 2-formylbenzoic acid

A robust iridium catalyst performs the reductive amination of the renewable levulinic acid and of 2-formylbenzoic acid in water under mild conditions. This catalyst tolerates very bulky reagents.

Clean and efficient conversion of renewable levulinic acid to levulinate esters catalyzed by an organic-salt of H4SiW12O40

Abstract An organic-salt of H4SiW12O40, (C10H7NO2)4H4SiW12O40, was prepared through the combination of H4SiW12O40 and quinaldic acid. The organic-salt was characterized by element analysis, FT-IR, UV–vis, XRD, SEM, TG, potentiometric titration and NH3-TPD. And its catalytic activity was tested in the synthesis of levulinate esters as a solid acid catalyst. The influences of various reaction conditions such as reaction time, catalyst amount and molar ration of ethanol to levulinic acid on the conversion of levulinic acid were investigated. The organic-salt still maintained the Keggin structure of pure H4SiW12O40 and has strong acidity. It exhibited excellent catalytic performances, including high yield of esters and good reusability. The conversion of levulinic acid could reach 98.6% in the esterification of levulinic acid and ethanol under the optimized reaction conditions. The results showed that the acid strength of catalyst played a very important role in the esterification.

New levulinic acid-based deep eutectic solvents: Synthesis and physicochemical property determination

Recently, deep eutectic solvents (DESs) have emerged as new and inexpensive ionic liquids (ILs) analogues. They possess attractive and similar solvent properties with traditional ILs. In present work a serials of DESs were prepared by pairing renewable levulinic acid (LA) as hydrogen donor with seven quarternary ammonium salts as hydrogen acceptor. The samples were further characterized in the temperature ranging from 293.15 to 333.15K at atmospheric pressure with the results of density (0.99891–1.17735gcm−3), dynamic viscosity (12.70–376.50mPas), electrical conductivity (0.35–8.27mScm−1), and refractive index data (1.44384–1.47273). The temperature dependence of these properties was explored and correlated with simple linear or Vogel-Fulcher-Tamman (VFT) models. The volume expansivities (β), molar volumes (Vm), molar refractions (Rm), and free volumes (fm) values have been calculated on the basis of density and refractive index data. The active energy of viscosity (Eη), molar electric conductivity (Λ), and ionicity were also determined. Partial structure-property relationship for DESs was also investigated. The tunable properties make DESs as a potential reaction medium, electrochemical process medium, solvent and absorbent. Therefore, the determination and correlation can provide relevant information for the engineering and industrial applications of DESs.

Efficient conversion of renewable levulinic acid to n-butyl levulinate catalyzed by ammonium and silver co-doped phosphotungstic acid

Ammonium and silver co-doped phosphotungstic acid was developed as novel efficient catalyst for the synthesis of n-butyl levulinate. The catalyst was characterized by element analysis, FT-IR, XRD and Hammett indicator method. Among them, (NH4)0.5Ag0.5H2PW12O40 exhibited the highest catalytic activity, and the yield of n-butyl levulinate could reach up to 99.0% within 2h. The results showed that the activity of (NH4)0.5Ag0.5H2PW12O40 was higher than that of single Ag+ or NH4+ doped H3PW and other representative catalysts reported by literatures. In addition, (NH4)0.5Ag0.5H2PW12O40 performed good reusability for this reaction.

Optimization of renewable levulinic acid production from glucose conversion catalyzed by Fe/HY zeolite catalyst in aqueous medium

Levulinic acid (LA) is a versatile chemical with numerous applications. In this study, the conversions of glucose and oil palm fronds (OPF) to LA have been conducted over 10% Fe/HY zeolite catalyst. The optimization of LA yield from glucose conversion using Box–Behnken design and response surface methodology reported 61.8% yield, which can be achieved at temperature 173.4°C, reaction time 3.3h, 0.93g of glucose and 0.89g 10% Fe/HY zeolite. The LA yield from OPF conversion conducted at the optimum conditions was 17.6% with 54.8% process efficiency. It was also observed that Fe leaching from 10% Fe/HY zeolite was insignificant and recycled 10% Fe/HY zeolite gave sufficient performance for five successive cycles. This study emphasizes the potential of Fe/HY zeolite catalyst for catalytic conversion of lignocellulosic biomass to LA.

Environmentally benign catalytic process for esterification of renewable levulinic acid to various alkyl levulinates biodiesel

This study explores, the use of modified zeolite (Micro/Meso‐HZ‐5) obtained by desilication post‐treatment as heterogeneous catalyst for esterification of biomass derived renewable levulinic acid (LA) with different alkyl alcohols such as methanol, ethanol, n‐butanol, and n‐octanol aiming to produce corresponding alkyl levulinate. This method of production of alkyl levulinates would be sustainable process, as it can be used as novel miscible diesel biofuels preventing global warming by decreasing atmospheric CO2.The LA conversion obtained over Micro/Meso‐HZ‐5 was higher than H‐ZSM‐5, which is due to the combined effect of increase in Brönsted acid sites, total acidity, and other properties such as BET surface area and the generation of mesoporosity. The maximum LA conversion of 91, 95, 96, and 98% with 100% selectivity toward alkyl levulinate was obtained, when LA was being esterified over Micro/Meso‐HZ‐5 with methanol, ethanol, n‐butanol, and n‐octanol, respectively, at optimal process parameters. Micro/Meso‐HZ‐5 catalyst was found to be reusable for six cycles.Furthermore, pseudo homogeneous (P‐H) kinetic model of the esterification of LA with the studied four alcohols were established with R2 > 0.99, using the experimental data. A P‐H kinetic model implies that, the esterification reaction follows second order reversible kinetics. © 2014 American Institute of Chemical Engineers Environ Prog, 34: 795–801, 2015

Production of octyl levulinate biolubricant over modified H-ZSM-5: Optimization by response surface methodology

The present study highlighted the use of modified H-ZSM-5 (Meso-HZ-5) as heterogeneous catalyst for the synthesis of octyl levulinate biolubricant by catalytic esterification of biomass derived renewable levulinic acid (LA) with n-octanol. The process variables such as catalyst loading (X1), n-octanol to LA molar ratio (X2) and reaction temperature (X3) were optimized through response surface methodology (RSM), using Box-Behnken model. Analysis of variance was performed to determine the adequacy and significance of the quadratic model. The yield of octyl levulinate was obtained to be 99% at optimum process parameters. The developed quadratic model was found to be adequate and statistically accurate with correlation value (R2) of 0.9971 to predict the yield of octyl levulinate biolubricant. The study was also extended on the validation of theoretical and experimental data, including catalyst reusability.

From Renewable Levulinic Acid to a Diversity of 3-(Azol-3-yl)Propanoates

Efficient heterocyclization of methyl 7,7,7-trifluoro-4-methoxy-6-oxo-4-heptenoate and methyl 7,7,7-trichloro-4-methoxy-6-oxo-4-heptenoate into isoxazole and pyrazole derivatives that represent a new type of glutamate-like 3-(trihalomethylated-1,2-azol-3-yl)propanoate is reported. Preparation of the key methyl 7,7,7-trihalo-4-methoxy-6-oxohept-4-enoate precursors from levulinic acid is also described. The synthetic potential of this synthetic protocol was indicated by the production of several methyl and ethyl 3-(isoxazol-3-yl)propanoates and 3-(1H-pyrazol-3-yl)propanoates, and the respective acid derivatives, in good (70–95%) yields. The crystal structure for ethyl 5-(3-ethoxy-3-oxopropyl)-1H-pyrazole-3-carboxylate (10c) has been determined by monocrystal X-ray diffraction analysis. The N–H…H intermolecular hydrogen bonds join the molecules into catamer.

Esterification of renewable levulinic acid to ethyl levulinate biodiesel catalyzed by highly active and reusable desilicated H‐ZSM‐5

AbstractBACKGROUNDIn the near future, fossil fuel will have limitations in terms of availability and also great concerns over its environmental impact. New routes and related technologies based on renewable feedstocks can overcome most of these problems associated with fossil fuel. Among current biodiesel sources, ethyl levulinate (EL) biodiesel obtained from catalytic esterification of renewable levulinic acid (LA) with ethanol has received a great deal of attention. The use of desilicated H‐ZSM‐5 (DH‐ZSM‐5) as heterogeneous acid catalyst for EL biodiesel production in a closed system (under autogeneous pressure) was studied.RESULTSThe effect of reaction parameters such as ethanol to LA molar ratio (4:1 to 10:1), catalyst to LA ratio (0.10–0.25), speed of agitation (100–400 rpm), particle size (53–355 µm), reaction temperature (363–403 K) and reaction time (7 h) was investigated to maximize LA conversion.CONCLUSIONLevulinic acid conversion reached 95% over DH‐ZSM‐5 and the catalyst was reusable for up to six cycles. This LA conversion and the catalyst reusability values are higher than others reported in the literature. A pseudo‐homogeneous (P‐H) kinetic model indicated that reaction rate constants increased with increasing molar ratio, catalyst to LA ratio and reaction temperature. The activation energy decreased from 73.14 to 21.08 kJ mol‐1 when increasing the catalyst to LA ratio from 0.10 to 0.25, which implies a kinetically controlled reaction. © 2013 Society of Chemical Industry

Catalytic upgrading of renewable levulinic acid to ethyl levulinate biodiesel using dodecatungstophosphoric acid supported on desilicated H-ZSM-5 as catalyst

Levulinic acid (LA) is considered as a renewable platform chemical and can be used for the synthesis of variety of important fuels and chemicals. In particular, its esterification with ethanol produces ethyl levulinate (EL) would be green process, as it can be used as diesel miscible biofuel (DMB), preventing global warming by decreasing atmospheric CO2.This study explores the use of modified H-ZSM-5 by desilication viz.; DH-ZSM-5 and dodecatungstophosphoric acid (DTPA) loaded on DH-ZSM-5 for esterification of LA with ethanol aiming to EL. Different degree of desilication of H-ZSM-5 was performed by using aq. NaOH (0.2–1.5M) at 338K for 30min and then DTPA was loaded on these desilicated H-ZSM-5 (DH-ZSM-5) support. H-ZSM-5, DH-ZSM-5 and DTPA on these DH-ZSM-5 samples were characterized by powder X-ray diffraction (XRD), N2 adsorption–desorption, pyridine chemisorbed IR spectroscopy, Temperature Programmed Ammonia Desorption (TPAD). The increase in conversion of levulinic acid was observed from 28% to 94% with increase of DTPA loading from 0% to 15%. The increased LA conversion may be due to increase in total acidity from 43.14% to 84.31%.The use of DH-ZSM-5 as support for deposition of DTPA may be reported for the first time. The present work also extended to optimize process parameters such as DTPA loading on DH-ZSM-5, catalyst to LA ratio, LA to ethanol molar ratio, speed of agitation, particle size reaction temperature and catalyst reusability. Kinetic study based on pseudo-homogeneous (P-H) model is also presented. The experimental results follow second order kinetics.

Brønsted acidic ionic liquids catalyze the high-yield production of diphenolic acid/esters from renewable levulinic acid

The high-yielding synthesis of diphenolic acid (DPA) using Bronsted acidic ionic liquids (BAILs) has been demonstrated in this study. Importantly, p,p′-DPA was obtained as the preferential product over o,p′-DPA with an isomer ratio over 100. Moreover, diphenolic esters were also prepared in high yield through a one-pot method.