539-82-2Relevant academic research and scientific papers
Synthesis of the 'green apple ester' ethyl valerate in organic solvents by Candida rugosa lipase immobilized in MBGs in organic solvents: Effects of immobilization and reaction parameters
Raghavendra, Tripti,Sayania, Divya,Madamwar, Datta
, p. 31 - 38 (2010)
Ethyl valerate, also known as the green apple flavor is well known for its wide applications in the areas of food, pharmaceuticals and cosmetics industries. Candida rugosa lipase was immobilized in microemulsion based organogels (MBGs) and used for ethyl valerate synthesis in organic solvents. Various immobilization and reaction parameters were scrutinized for enhancement of ester production. Among the immobilization parameters, sodium bis-2-(ethylhexyl) sulfosuccinate (AOT), n-heptane and gelatin were found to be the highest yielding combination. Cyclohexane was found to be the solvent of choice as the reaction medium while pH 7, 40 °C and 1:1.6 ratio of valeric acid to ethanol were the reaction parameters exhibiting highest ester formation. The organogels were highly stable in the solvents and were reused for nine cycles with meager loss of activity. Also, immobilized enzyme was thermostable at 50-70 °C for ten hours. Hence, MBGs verify to be a promising enzyme immobilization system for ester synthesis in organic solvents.
Thermoalkalophilic lipase from an extremely halophilic bacterial strain Bacillus atrophaeus FSHM2: Purification, biochemical characterization and application
Ameri, Atefeh,Shakibaie, Mojtaba,Faramarzi, Mohammad Ali,Ameri, Alieh,Amirpour-Rostami, Sahar,Rahimi, Hamid Reza,Forootanfar, Hamid
, p. 151 - 160 (2017)
The present study was designed to isolate and identify an extremely halophilic lipase-producing bacterial strain, purify and characterize the related enzyme and evaluate its application for ethyl and methyl valerate synthesis. Among four halophilic isolates, the lipolytic ability of one isolate (identified as Bacillus atrophaeus FSHM2) was confirmed. The enzyme (designated as BaL) was purified using three sequential steps of ethanol precipitation and dialysis, Q-Sepharose XL anion-exchange chromatography and SP Sepharose cation-exchange chromatography with a final yield of 9.9% and a purification factor of 31.8. The purified BaL (Mw～85 kDa) was most active at 70 °C and pH 9 in the presence of 4?M NaCl and retained 58.7% of its initial activity after 150 min of incubation at 80 °C. The enzyme was inhibited by Cd2+ (35.6 ± 1.7%) but activated by Ca2+ (132.4 ± 2.2%). Evaluation of BaL's stability in the presence of organic solvents showed that xylene (25%) enhanced the relative activity of the enzyme to 334.2 ± 0.6% after 1 h of incubation. The results of esterification studies using the purified BaL revealed that maximum ethyl valerate (88.5%) and methyl valerate (67.5%) synthesis occurred in the organic solvent medium (xylene) after 48 h of incubation at 50 °C.
High yield of ethyl valerate from the esterification of renewable valeric acid catalyzed by amino acid ionic liquids
Dong, Lin-Lin,He, Ling,Tao, Guo-Hong,Hu, Changwei
, p. 4806 - 4813 (2013)
Ethyl valerate (EV) as a promising fuel additive was produced by esterification of valeric acid with ethanol over Bronsted acidic amino acid ionic liquids. Hammett method and density functional theory (DFT) calculations were preformed to evaluate the acidities of the catalysts. The composition of catalyst, reaction temperature, reaction time, molar ratio of reactants, amount of catalyst, and recycling ability of the catalyst were investigated. Proline bisulfate (ProHSO4) ionic liquid has the highest catalytic activity and the best recyclability under the optimized esterification conditions. A high conversion of valeric acid (>99.9%) was obtained for 7 h at 80 °C, with 100% selectivity of EV. The density, viscosity, melting point, boiling point, elemental analysis and heat of combustion of the EV product were measured. The density of EV is 0.896 g cm -3. The viscosity of EV was 1.7 cP at room temperature. The heating values of EV are 4158.1 kJ mol-1 and 31.9 kJ g-1. EV obtained from esterification has higher energy density than methanol, ethanol, γ-valerolactone, and valeric acid, which illustrates that EV is a promising biofuel candidate.
Design, Synthesis, and Study of the Insecticidal Activity of Novel Steroidal 1,3,4-Oxadiazoles
Bai, Hangyu,Jiang, Weiqi,Li, Qi,Li, Tian,Ma, Shichuang,Shi, Baojun,Wu, Wenjun
, p. 11572 - 11581 (2021/10/12)
A series of novel steroidal derivatives with a substituted 1,3,4-oxadiazole structure was designed and synthesized, and the target compounds were evaluated for their insecticidal activity against five aphid species. Most of the tested compounds exhibited potent insecticidal activity against Eriosoma lanigerum (Hausmann), Myzus persicae, and Aphis citricola. Compounds 20g and 24g displayed the highest activity against E. lanigerum, showing LC50 values of 27.6 and 30.4 μg/mL, respectively. Ultrastructural changes in the midgut cells of E. lanigerum were detected by transmission electron microscopy, indicating that these steroidal oxazole derivatives might exert their insecticidal activity by destroying the mitochondria and nuclear membranes in insect midgut cells. Furthermore, a field trial showed that compound 20g exhibited effects similar to those of the positive controls chlorpyrifos and thiamethoxam against E. lanigerum, reaching a control rate of 89.5% at a dose of 200 μg/mL after 21 days. We also investigated the hydrolysis and metabolism of the target compounds in E. lanigerum by assaying the activities of three insecticide-detoxifying enzymes. Compound 20g at 50 μg/mL exhibited inhibitory action on carboxylesterase similar to the known inhibitor triphenyl phosphate. The above results demonstrate the potential of these steroidal oxazole derivatives to be developed as novel pesticides.
Selective production of γ-valerolactone and ethyl valerate from ethyl levulinate using unsupported nickel phosphide
Golubeva, Maria A.,Maximov, Anton L.
, (2021/11/01)
Unsupported nickel phosphide catalyst containing Ni2P phase was applied in the hydrodeoxygenation of ethyl levulinate in ethanol medium for the first time. The obtained catalyst was investigated by XRF, XRD, NH3–TPD, XPS and TEM techniques. γ-valerolactone and ethyl valerate were obtained as the hydrodeoxygenation products. Varying the temperature and the reaction time it was possible to obtain these products with high selectivity. γ-valerolactone was selectively formed at 200–250 °C and ethyl valerate was selectively formed at temperatures of 300–350 °C. Increase in reaction time was contributed to ethyl valerate formation. The highest selectivity of ethyl valerate was 100% at full ethyl levulinate conversion at 350 °C after 6 h. 100% γ-valerolactone selectivity was reached at low conversion of ethyl levulinate. The highest yield of γ-valerolactone reached 41.7% after 6 h of the reaction at 250 °C. The selectivity of γ-valerolactone was 86.9% and the conversion of ethyl levulinate was 48.0%.
The relevance of Lewis acid sites on the gas phase reaction of levulinic acid into ethyl valerate using CoSBA-xAl bifunctional catalysts
Cecilia, J. A.,Dumesic, J. A.,Jiménez-Gómez, C. P.,López Granados, M.,Maireles-Torres, P.,Mariscal, R.,Mu?oz-Olasagasti, M.
, p. 4280 - 4293 (2021/06/30)
A series of Co supported on Al-modified SBA-15 catalysts has been studied in the gas phase direct transformation of levulinic acid (LA) into ethyl valerate (EV) using a continuous fixed-bed reactor and ethanol as solvent. It was observed that once the intermediate product gamma-valerolactone (GVL) has been formed, the presence of aluminum is required for the selective transformation to EV. Three Lewis acid sites (LAS) are identified (from highest to lowest acid strength): aluminum ions in tetrahedral and octahedral coordination and Co2+sites. The intrinsic activity of these LAS for the key reaction, the GVL ring opening, decreases with the strength of these acid sites, but so does the undesirable formation of coke, also catalyzed by these centers. The best catalyst was that with the highest Al content, CoSBA-2.5Al, that reached an EV yield of up to 70%. This result is associated with the presence of LAS attributed to the presence of Co2+surface species that, although having low intrinsic activity in the selective GVL ring-opening reaction, are highly concentrated in this sample and also possess less activity in the undesirable and deactivating formation of coke. These Co2+LAS have been stabilized by incorporation of aluminum into the support, modifying the reducibility and dispersion of cobalt species. Additionally, the lower proportion of metallic Co species decreases the hydrogenating capacity of this catalyst. This decrease is a positive result because it prevents GVL hydrogenation to undesired products. This catalyst also showed promising stability in a 140 h on-stream run.
Zeolite-Tailored Active Site Proximity for the Efficient Production of Pentanoic Biofuels
Chen, Shaohua,Chen, Tiehong,Chu, Shengqi,Gu, Qingqing,He, Jiang,Liu, Yuanshuai,Luo, Wenhao,Wang, Aiqin,Weckhuysen, Bert M.,Wu, Zhijie,Yang, Bing,Zhang, Tao,Zhang, Yafeng
supporting information, p. 23713 - 23721 (2021/09/22)
Biofuel production can alleviate reliance on fossil resources and thus carbon dioxide emission. Hydrodeoxygenation (HDO) refers collectively to a series of important biorefinery processes to produce biofuels. Here, well-dispersed and ultra-small Ru metal nanoclusters (ca. 1 nm), confined within the micropores of zeolite Y, provide the required active site intimacy, which significantly boosts the chemoselectivity towards the production of pentanoic biofuels in the direct, one-pot HDO of neat ethyl levulinate. Crucial for improving catalyst stability is the addition of La, which upholds the confined proximity by preventing zeolite lattice deconstruction during catalysis. We have established and extended an understanding of the “intimacy criterion” in catalytic biomass valorization. These findings bring new understanding of HDO reactions over confined proximity sites, leading to potential application for pentanoic biofuels in biomass conversion.
Catalytic transfer hydrogenation of ethyl levulinate to γ-valerolactone over supported MoS2catalysts
Diao, Xinyong,Ji, Na,Jiang, Sinan,Liu, Caixia,Liu, Qingling,Liu, Zhenyu,Lu, Xuebin,Ma, Degang,Song, Chunfeng,Yu, Zhihao
, p. 5062 - 5076 (2021/08/16)
The hydrogenation of levulinate esters to γ-valerolactone (GVL) is an important step in the transformation of biomass into biofuels. It is attractive to develop new efficient systems for the catalytic transfer hydrogenation (CTH) of levulinate esters to value-added GVL. In this work, a series of MoS2-based supported catalysts were prepared via an impregnation method for the CTH of biomass-derived ethyl levulinate (EL) to GVL. By comprehensive characterization and catalytic measurements, we found that the CTH activity of EL to GVL is closely related to the MoS2 morphology and acid distribution on the support. Among the catalysts with different supports, the AC support with abundant Lewis acid sites and large surface area facilitated the high dispersion of low stacked MoS2 slabs, and the MoS2-acid synergistic catalysis contributed to the superior activity and selectivity. The conversion of EL and the selectivity of GVL reached 97.2% and 91.2% under optimized conditions over the MoS2/AC catalyst (230 °C, 1 MPa H2, 1.5 h), respectively. We also conducted reaction kinetic experiments to reveal the relationship between the active site of the MoS2/AC catalyst and its catalytic performance, and the plausible reaction pathway and mechanism over MoS2/AC was proposed. The catalytic performance gradually declined during recycling tests due to the oxidation of MoS2 and can be easily recovered by resulfuration.
In Situ Generated Nickel Phosphide Based Catalysts for Hydroprocessing of Levulinic Acid
Golubeva
, p. 670 - 675 (2021/03/29)
Abstract: This article describes the production of unsupported nickel phosphide catalysts generated in situ in а reaction mixture from water-soluble and oil-soluble precursors during the hydroconversion of levulinic acid. These catalysts contain crystalline phases, specifically Ni12P5 and Ni(PO3)2. During the hydrogenation of levulinic acid in toluene in the presence of NiP–TOP, a lower temperature and a shorter reaction time contribute to the formation of γ-valerolactone (100% selectivity). A higher temperature and a longer reaction time favor the formation of valeric acid (94% selectivity). In the hydrogenation of levulinic acid in ethanol in the presence of NiP–H3PO2, the main reaction product is ethyl levulinate (95% selectivity).
Eco-Friendly Natural Clay: Montmorillonite Modified with Nickel or Ruthenium as an Effective Catalyst in Gamma-Valerolactone Synthesis
?erveny, Libor,Trejbal, Ji?í,Vaňková, Michaela,Vrbková, Eva,Vysko?ilová, Eli?ka
, (2021/07/25)
Ni/Ru metals supported on cheap and available support montmorillonite K10 were used for the selective hydrogenation of levulinic acid to γ-valerolactone. Different loadings of the metals were applied by the impregnation method, and detailed characterization was performed (UV–VIS, XRD, TPR, TPD, particle size distribution, SEM, XRF). Metals’ homogeneous distribution on the surface was confirmed. The selectivity to the desired product was almost independent on the used material. A detailed study of the influence of solvents on the studied reaction was also performed—protic alcohol-based solvents caused the formation of levulinic and valeric acid esters in the reaction mixture. The selectivity was influenced mainly by the alcohol structure (the highest selectivity obtained using isopropyl alcohol and sec-butanol). Mainly the solvent’s donor number (except ethanol) influenced the reaction rate. The prepared catalysts are promising, available, and cheap materials for the studied reaction. Solvent may significantly influence the yield of γ-valerolactone. Graphic Abstract: [Figure not available: see fulltext.].
