20279-49-6Relevant articles and documents
Inexpensive and tuneable protic ionic liquids based on sulfuric acid for the biphasic synthesis of alkyl levulinates
Chrobok, Anna,Gillner, Danuta,Matuszek, Karolina,Przypis, Marta,Swad?ba-Kwa?ny, Ma?gorzata
, (2020)
Alkyl levulinates are bio-derived chemicals, increasingly popular for their uses as solvents, additives and intermediates. However, efficient and recyclable catalysts for their synthesis are still the subject of intensive research. In this study, a wide range of alkyl levulinates was synthesized under mild conditions (room temperature, atmospheric pressure), using inexpensive and efficient Br?nsted acidic ionic liquids (ILs) based on sulfuric acid and off-the-shelf bases. Acidity of the ILs was closely related to their activity. The ILs could be easy separated and recycled, without significant changes in conversion or selectivity over 10 cycles (yields ca. 90–95%). Under optimized conditions, a 99% yield of pentyl levulinate (model reaction) was achieved. The method was demonstrated to be efficient in the synthesis of levulinates of C1-C16 linear, branched and cyclic alcohols. This innovative, green route to alkyl levulinates fits well within the sustainable development strategy.
Catalytic conversion of furfuryl alcohol or levulinic acid into alkyl levulinates using a sulfonic acid-functionalized hafnium-based MOF
Gupta, Shyam Sunder R.,Kantam, Mannepalli Lakshmi
, p. 62 - 66 (2019)
Biomass conversion using reusable solid acid catalysts are highly desirable to comply with the principles of green chemistry. Here, we report a sulfonic acid-functionalized hafnium-based metal-organic framework (MOF), UiO-66(Hf)-SO3H, as an efficientsolid acidcatalyst for the alcoholysis of furfuryl alcohol (FA) andesterification of levulinic acid (LA) affording alkyl levulinates (ALs). Among the as prepared UiO-66 based MOFs(UiO-66(Hf), UiO-66(Hf)-NH2, UiO-66(Hf)-SO3H and UiO-66(Zr)-SO3H), UiO-66(Hf)-SO3H holds highest Br?nsted acidity and therefore exhibits excellent catalytic activity towards production of ALs. The highest Br?nsted acidity in UiO-66(Hf)-SO3His the result of the covalently bound sulfonic acid groups present inorganic linkers along with the ligated hydroxyl groups (Hf-μ3-OH) to the Hf metal clusters.
Green syntheses of levulinate esters using ionic liquid 1-Methyl imidazolium hydrogen sulphate [MIM][HSO4] in solvent free system
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In the present work, n-butyl levulinate is synthesized by esterification of levulinic acid (LA) with n-butanol using Br?nsted acidic ionic liquid [MIM][HSO4] as a catalyst in a solvent free condition. The prepared IL was characterized by FT-IR, 13C‐NMR and 1H–NMR. For optimization study, central composite design (CCD) method was employed. Design of experiments and statistical analysis is performed using Design Expert 11 software. The highest yield 89.6% and selectivity 98.1% of n-butyl levulinate were achieved at 90 °C. Biphasic layers of product and IL were observed resulting in self-separation of product. Effects of changes in variable parameters on conversion like LA: n-butanol molar ratio, LA:IL molar ratio and temperature were studied. Arrhenius plot was obtained and Activation energy (Ea) was calculated as 53.16 KJ/mol. Substrate study was performed on sec-, iso-, and tert-butanol and 1-Pentanol and n-Hexanol giving high yield and selectivity of corresponding levulinate esters. Catalyst was reused five times without significant decrease in yield.
Acidic ion functionalized N-doped hollow carbon for esterification of levulinic acid
Zhang, Qifang,Jiang, Pingping,Nie, Zhixin,Zhang, Pingbo
, p. 1588 - 1593 (2020)
Acidic ion functionalized N-doped hollow carbon (NHC-[C4N][SO3CF3]) has been successfully synthesized by quaternization of N-doped hollow carbon (NHC) with 1,4-butanesultone, followed by ion exchange with trifluoromethanesulfonic acid. The catalyst was characterized by Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), acid-base titration techniques and other methods. A hollow spherical catalyst with regular morphology, high acid density (2.72 mmol g-1) and good stability was obtained. Various characterizations showed that NHC-[C4N][SO3CF3] possesses abundant nanopores (3.41 nm), large Brunauer-Emmett-Teller (BET) surface area (154 m2 g-1) and strong and controllable Br?nsted acid sites. The as-prepared NHC-[C4N][SO3CF3] was then used for the acid-catalyzed esterification of levulinic acid with ethanol. At the optimum conditions, the highest conversion of levulinic acid reached 94.17% and high conversion was maintained after recycling four times. Further investigation of the catalytic activity in the esterification of different aliphatic and aromatic alcohols with levulinate was carried out, showing good results.
Catalytic synthesis of levulinate esters over zirconia and its modified forms coated on honeycomb monoliths: Green synthesis
Serrao, Reena Saritha,Mohamed Shamshuddin,D'Souza, Joyce
, p. 1993 - 1999 (2019)
A series of solid acid catalysts such as ZrO2, Mo(VI)/ZrO2 and W(VI)/ZrO2 have been coated on honeycomb monoliths as well as synthesized in the powder forms and used as catalytic materials for synthesis of ethyl levulinate from levulinic acid and ethanol. These solid acids were characterized by BET, NH3-TPD/n-butyl amine back titration, FTIR, PXRD and SEM techniques. Effects of various reaction parameters towards the reaction performance were studied. The performance of the catalyst was tested based on nature of the catalyst (honeycomb coated or powder form), reaction time (1 to 5 h), molar ratio (1:1 to 1:12 levulinic acid to ethanol) and reusability of the catalytic material. An excellent yield (86-88 %) of ethyl levulinate was obtained under optimized conditions. An attempt is made to correlate the activity of the catalysts in this esterification reaction with their surface characteristics. The honeycomb monoliths coated with zirconia and its modified forms were found to be ecofriendly, cost-effective and reusable catalytic materials compared to their powder forms.
Method for preparing alkyl levulinate by regulating water content
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Paragraph 0060; 0061, (2020/04/17)
The invention discloses a method for preparing alkyl levulinate by regulating water content. The method comprises the following steps: at least mixing furfuryl alcohol, alkyl alcohol and an acidic catalyst to form a reaction system, carrying out a reaction under the conditions of continuous stirring and reflux condensation, regulating the content of water in the reaction system to enable a mol ratio of the furfuryl alcohol to the water to be 1: (0.1-5), and carrying out aftertreatment to obtain alkyl levulinate. The structural formula of the alkyl levulinate is as shown in the specification. In the structural formula, R is any one selected from the group consisting of -CH3, -C2H5, -C3H7, -C4H9 and -C5H11. Compared with the prior art, the method provided by the invention has the advantagesthat the alkyl levulinate is prepared by regulating the water content; process is simple and feasible; conditions are mild; cost is low; few byproducts are produced; maximum yield reaches 99.8%; and the problem of low yield of alkyl levulinate in conventional synthesis methods is solved.
Silica-supported sulfonic acids as recyclable catalyst for esterification of levulinic acid with stoichiometric amounts of alcohols
Maggi, Raimondo,Shiju, N. Raveendran,Santacroce, Veronica,Maestri, Giovanni,Bigi, Franca,Rothenberg, Gadi
supporting information, p. 2173 - 2180 (2016/10/18)
Converting biomass into value-added chemicals holds the key to sustainable long-term carbon resource management. In this context, levulinic acid, which is easily obtained from cellulose, is valuable since it can be transformed into a variety of industrially relevant fine chemicals. Here we present a simple protocol for the selective esterification of levulinic acid using solid acid catalysts. Silica supported sulfonic acid catalysts operate under mild conditions and give good conversion and selectivity with stoichiometric amounts of alcohols. The sulfonic acid groups are tethered to the support using organic tethers. These tethers may help in preventing the deactivation of the active sites in the presence of water.
Graphene oxide: An efficient acid catalyst for alcoholysis and esterification reactions
Zhu, Shanhui,Chen, Chengmeng,Xue, Yanfeng,Wu, Jianbing,Wang, Jianguo,Fan, Weibin
, p. 3080 - 3083 (2015/02/02)
Evidence is presented for graphene oxide (GO), prepared by modified Hummers method, as a highly active, selective and reusable solid-acid catalyst for the production of alkyl levulinates via alcoholysis or esterification. 95.5% yield of ethyl levulinate was achieved by GO in furfuryl alcohol alcoholysis. Moreover, the surface SO3H groups were identified as the primary active sites, while the surface carboxyl groups worked synergistically to adsorb furfuryl alcohol.
Efficient and selective alcoholysis of furfuryl alcohol to alkyl levulinates catalyzed by double SO3H-functionalized ionic liquids
Wang, Guofeng,Zhang, Zhanquan,Song, Linhua
, p. 1436 - 1443 (2014/03/21)
The production of alkyl levulinates from furfuryl alcohol (FAL) in alcohol media was investigated at moderate temperature in the presence of Bronsted acidic ionic liquids. The reaction was examined and optimized under batch conditions, where it was found that furfuryl alcohol was rapidly and almost quantitatively converted into intermediate products including 2-alkoxymethylfuran and 4,5,5-trialkoxypentan-2-one, and high alkyl levulinates yield of 95% can be achieved after reaching a steady state in 2 h. An advantage of this catalyst system is that undesired dialkyl ether (DEE) formed by a side reaction of the dehydration of alcohol is negligible. The Hammett method was used to determine the acidities of these ionic liquids, which indicated that the acidity and the molecular structure have strong effects on the catalytic activity of ionic liquids. Based on the experimental results, a possible mechanism for the alcoholysis of FAL is proposed.
PROCESS FOR THE REACTIVE EXTRACTION OF LEVULINIC ACID
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Page/Page column 13-15, (2008/06/13)
A process for the reactive extraction of levulinic acid from an aqueous mixture comprising levulinic acid, wherein the aqueous mixture is contacted with a liquid esterifying alcohol, which alcohol has at least four carbon atoms and is substantially water-immiscible, at esterification conditions in the presence of a catalyst at a temperature in the range of from 50 to 250 °C, to form a levulinate ester, wherein the amount of alcohol is such that the liquid alcohol extracts the ester from the aqueous mixture and an aqueous phase comprising the catalyst and having a reduced levulinic acid content and an organic phase comprising alcohol and levulinate ester is formed.
