111-82-0Relevant articles and documents
Amino acid variability in the peptide composition of a suite of amphiphilic peptide siderophores from an open ocean Vibrio species
Gauglitz, Julia M.,Butler, Alison
, p. 489 - 497 (2013)
In response to iron-depleted aerobic conditions, bacteria often secrete low molecular weight, high-affinity iron(III)-complexing ligands, siderophores, to solubilize and sequester iron(III). Many marine siderophores are amphiphilic and are produced in suites, wherein each member within a particular suite has the same iron(III)-binding polar head group which is appended by one or two fatty acids of differing length, degree of unsaturation, and degree of hydroxylation, establishing the suite composition. We report the isolation and structural characterization of a suite of siderophores from marine bacterial isolate Vibrio sp. Nt1. On the basis of structural analysis, this suite of siderophores, the moanachelins, is amphiphilic and composed of two N-acetyl-N-hydroxy-d- ornithines, one N-acetyl-N-hydroxy-l-ornithine, and either a glycine or an l-alanine, appended with various saturated and unsaturated fatty acid tails. The variation in the small side-chain amino acid is the first occurrence of variation in the peptidic head group structure of a set of siderophores produced by a single bacterium.
Solid acid catalysts for biodiesel production - Towards sustainable energy
Kiss, Anton A.,Dimian, Alexandre C.,Rothenberg, Gadi
, p. 75 - 81 (2006)
The advantages of biodiesel as an alternative fuel and the problems involved in its manufacturing are outlined. The pros and cons of making biodiesel via fatty acid esterification using solid acid catalysts are examined. The main problem is finding a suitable catalyst that is active, selective, and stable under the process conditions. Various solid acids (zeolites, ion-exchange resins, and mixed metal oxides) are screened as catalysts in the esterification of dodecanoic acid with 2-ethylhexanol, 1-propanol, and methanol at 130-180°C. The most promising candidate is found to be sulphated zirconia. The catalyst's stability towards thermal decomposition and leaching is tested and the effects of the surface composition and structure on the catalytic activity are discussed.
Iridium-catalysed isomerising trialkylsilylation of methyl oleateq
Huber, Thimo,Firlbeck, Doris,Riepl, Herbert M.
, p. 144 - 148 (2013)
Monounsaturated fatty acids from vegetable oils are attractive substrates for applications as renewable feedstock in polymer industry. Applying the concept of transition metal-catalysed isomerising functionalisation, their nearly inaccessible internal C]C double bond can be transformed into products with a functional group in the terminal position. In this work, methyl oleate is shown to undergo [Ir(OMe)( cod)]2-catalysed dehydrogenative silylation with triethylsilane to give terminal vinylsilanes 4 in 69% yield. Independent preparation of reference substances is helpful in identifying the desired products in gas chromatograms of complex reaction mixtures.
Enhanced activity over alkyl/aryl functionalized porous pillared-zirconium phosphates in liquid-phase reaction
Liu, Ke,Wang, Xueyan,Ding, Shengda,Li, Ying,Hua, Weiming,Yue, Yinghong,Gao, Zi
, p. 84 - 89 (2013)
A series of porous pillared-zirconium phosphates functionalized with methyl, ethyl, propyl and phenyl groups were prepared and characterized by SEM, 29Si MAS NMR, TG and N2 adsorption. Their total surface acidity and accessible one were measured by potentiometric titration of n-butylamine and liquid phase 2,6-di-tert-butyl-pyridine adsorption, respectively. The catalytic behaviors of these hybrid materials for alkylation of hydroquinone and esterification of lauric acid were compared. Not the total acid sites but the accessible ones play a crucial role in both reactions of alkylation and esterification. The accession for acid sites can be enhanced by the introduction of alkyl/aryl groups, due to the improved hydrophobicity of the surface.
Development of an environmentally benign process for the production of fatty acid methyl esters
Jordan,Gutsche
, p. 99 - 105 (2001)
The production of fatty acid methyl esters (FAME) is an important intermediate step in oleochemistry. The oleochemical production route starts with the renewable raw materials fat and oil and ends at fatty alcohols and different special products. Fatty acid methyl esters can be formed at mild reaction temperatures by transesterification of natural triglycerides (fats and oils). This contribution will show the development of a continuous process which is considering the main principles of production integrated environmental protection. The main advantages of this process are low energy consumption and minimal waste production. The process alternatives are shown and a scope on future problems which have to be solved to reach a real additional improvement of the fatty acid methyl esters production is given.
Heterogeneous esterification of fatty acids with methanol catalyzed by Lewis acidic organozirconium complexes with Keggin-type mono-aluminum-substituted polyoxotungstates
Kato, Chika Nozaki,Ogasawara, Tsukasa,Kondo, Akari,Kato, Daichi
, p. 41 - 45 (2017)
Two Lewis acidic organozirconium complexes with α-Keggin-type mono-aluminum-substituted polyoxotungstates, [(n-C4H9)4N]6[α-PW11Al(OH)O39ZrCp2]2 (Cp = η5-C5H5?) (TBA-P-Al-Zr) and [(n-C4H9)4N]6[α-SiW11Al(OH)2O38ZrCp2]2·2H2O (TBA-Si-Al-Zr), were used as heterogeneous catalysts for the esterification of various fatty acids with methanol. For the esterification of linoleic acid at 80 ± 2 °C, TBA-P-Al-Zr exhibited 83% conversion after 6 h, approximately six times higher than that of TBA-Si-Al-Zr. TBA-P-Al-Zr also exhibited 69–90% conversion for the esterification of oleic acid, palmitic acid, myristic acid, and lauric acid with methanol at 80 ± 2 °C.
Effects of acidity and immiscibility of lactam-based Bronsted-acidic ionic liquids on their catalytic performance for esterification
Zhou, Hancheng,Yang, Jing,Ye, Linmin,Lin, Haiqiang,Yuan, Youzhu
, p. 661 - 665 (2010)
Several lactam-based Bronsted-acidic ionic liquids with different acidities were synthesized and applied to the esterification of carboxylic acids with alcohols. High conversion and perfect selectivity were obtained under mild conditions. Among the ionic liquids investigated, those having a methyl sulfonate anion (which has weaker acidity than those with a tetrafluoroborate anion) afforded the highest activity for esterification. The results indicated that the acidity and immiscibility of Bronsted-acidic ionic liquids has a synergistic effect on their esterification performance. Furthermore, after removal of water under vacuum, such ionic liquids could be reused several times without substantial loss of activity.
Protic ionic liquids from di- or triamines: even cheaper Br?nsted acidic catalysts
Barteczko, Natalia,Brz?czek-Szafran, Alina,Byrne, Emily,Chrobok, Anna,Kolanowska, Anna,Swad?ba Kwa?ny, Ma?gorzata,Szelwicka, Anna,Wi?c?awik, Justyna
, p. 4421 - 4429 (2021)
Dicationic and tricationic ionic liquids, synthesised by proton transfer from sulfuric acid and corresponding di- and triamines, were characterised and used as Br?nsted acidic catalysts in biodiesel production. It has been demonstrated that the new ionic liquids are less expensive than those based on monoamines (even on triethylamine) and are highly acidic. Their performance in a model catalytic esterification reaction surpassed that of sulfuric acid and other literature reports, due to the capability of the ionic liquids to absorb water while phase-separating the ester, thereby shifting the reaction equilibrium towards products. The overall catalytic performance was an interplay between acidity (quantified by Gutmann AN) and physical properties: density and viscosity, which enabled easy phase separation, thereby separating water from the ester. The substrate scope and recycling studies have demonstrated that the new ionic liquids are robust and recyclable catalysts.
A new heterogeneous acid catalyst system for esterification of free fatty acids into methyl esters
Boey, Peng-Lim,Ganesan, Shangeetha,Maniam, Gaanty Pragas,Khairuddean, Melati,Lee, Siew-Ee
, p. 12 - 17 (2012)
A new heterogeneous acid catalyst system for production of environmentally friendly fuel, biodiesel was created from ferric sulfate and non-toxic, inexpensive source of biopolymer, sodium alginate. The catalyst, in the form of ferric-alginate beads produced from the reaction of 2 wt.% sodium alginate gel with 0.1 M ferric sulfate solution gave excellent methyl ester conversion of 98% with mild reaction conditions. The esterification of 0.5 g lauric acid was carried out at optimum conditions; 16 wt.% of ferric-alginate beads (2.8 wt.% Fe) methanol refluxing temperature, 15:1 methanol to lauric acid molar ratio for 3 h. The ferric-alginate beads were reusable up to 7 times without any pre-treatment. Characterization of the ferric-alginate beads showed the formation of FeOOH that held the alginate chain in place. Thermal analysis showed that the beads are able to withstand the refluxing temperature without degradation. Iron content was found to be 0.175 g Fe/g beads as determined by AAS and 0.189 g Fe/g beads as determined by TGA. Easy catalyst separation, reusability and ability of the ferric-alginate beads to esterify lauric acid to give high conversion of methyl laurate makes this catalyst desirable for biodiesel production from high free fatty acid oils.
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Takeda,K. et al.
, p. 3757 - 3766 (1972)
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Sulfonated porous organic polymer as a highly efficient catalyst for the synthesis of biodiesel at room temperature
Gomes, Ruth,Bhanja, Piyali,Bhaumik, Asim
, p. 110 - 116 (2016)
A new functionalized porous organic polymer bearing sulfonic acid groups (PDVTA-SO3H) at the pore surface with high surface area (SBET = 406 m2 g-1) and Bronsted acidity is reported. The material has been synthesized via post-synthetic sulfonation of the porous co-polymer poly-divinylbenzene-co-triallylamine (PDVTA-1) using chlorosulfonic acid as sulfonating agent. A detailed characterization of the -SO3H functionalized porous polymeric material has been carried out using N2 sorption, FT-IR and UV-vis spectroscopy, HR-TEM, FE-SEM, thermogravimetric and elemental analyses. Temperature programmed desorption of NH3 (TPD-NH3 analysis) of PDVTA-SO3H revealed a very high surface acidity of 2.3 mmol g-1. Such high acidity of PDVTA-SO3H has been explored to investigate its catalytic efficiency towards eco-friendly production of biodiesel via esterification of long-chain free fatty acids (FFA) to the respective fatty acid monoalkyl esters (FAMEs) at room temperature using methanol as reactant as well as solvent. The sulfonated porous polymer is found to be a very active and reusable solid acid catalyst giving high yields (～92-98%) of various biodiesel compounds under very mild reaction conditions.
The inhibition performance of hydroxy lauric imidazoline for mild steel in chloride solution saturated with CO2
Ma, Lan,He, Yi,Luo, Pin Ya,Zhan, Yingqing,Yang, Ran Ran,Zhou, Yanqiu
, p. 304 - 314 (2016)
In the paper, a novel hydroxy lauric imidazoline (HL-IM) was synthesized using lauric acid and ethylene diamine as raw materials. Methanol reaction method was introduced to prepare the hydroxy lauric imidazoline (HL-IM). According to the results of experiments, the optimum synthesis conditions of methanol reaction was determined through orthogonal experiment, which were: methyl laurate: ethylene diamine = 1: 1, sodium methoxide (0.75 wt %), reaction temperature 100°C, reaction time 2 h. The inhibition efficiency of HL-IM inhibitor was investigated in the condition of 5 wt % NaCl solutions saturated with CO2 at 333.15 K for 72 h. With 150 mg L–1 inhibitor dosage, the efficiency of inhibition reached 90.17% by weight loss method. Through film-forming property, foaming characteristic, and emulsification tendency test, it w a s shown that HL-IM had good water-solubility, a smaller emulsification tendency in 5 wt % NaCl solution, and a little foaming performance. Meanwhile, referring to the polarization curves tests, the synergistic effect of HL-IM with the potassium iodide, methylbutynol, and cetyltrimethyl ammonium bromide was studied.
Isatin based Schiff bases as inhibitors of α-glucosidase: Synthesis, characterization, in vitro evaluation and molecular docking studies
Rahim, Fazal,Malik, Fazal,Ullah, Hayat,Wadood, Abdul,Khan, Fahad,Javid, Muhammad Tariq,Taha, Muhammad,Rehman, Wajid,Ur Rehman, Ashfaq,Khan, Khalid Mohammed
, p. 42 - 48 (2015)
Isatin base Schiff bases (1-20) were synthesized, characterized by 1H NMR and EI/MS and evaluated for α-glucosidase inhibitory potential. Out of these twenty (20) compounds only six analogs showed potent α-glucosidase inhibitory potential with IC50 value ranging in between 2.2 ± 0.25 and 83.5 ± 1.0 μM when compared with the standard acarbose (IC50 = 840 ± 1.73 μM). Among the series compound 2 having IC50 value (18.3 ± 0.56 μM), 9 (83.5 ± 1.0 μM), 11 (3.3 ± 0.25 μM), 12 (2.2 ± 0.25 μM), 14 (11.8 ± 0.15 μM), and 20 (3.0 ± 0.15 μM) showed excellent inhibitory potential many fold better than the standard acarbose. The binding interactions of these active analogs were confirmed through molecular docking.
Polystyrene-based superacidic solid acid catalyst: Synthesis and its application in biodiesel production
Chang, Ying,Lee, Chohee,Bae, Chulsung
, p. 47448 - 47454 (2014)
A polystyrene-supported superacidic fluoroalkyl sulfonic acid catalyst (sPS-S) was synthesized using a combination of iridium-catalyzed C-H borylation and Suzuki-Miyaura coupling reactions. Catalytic activity of the new solid acid catalyst was examined for esterification of fatty acids and transesterification of triglyceride with methanol. Significantly higher activity than those of commercial sulfonated ion-exchange resins (Amberlyst 15 and Nafion NR50) was achieved with a catalyst loading as low as 0.5 wt%. The solid catalyst could be easily recovered by filtration and reused. Consistently high activities were obtained from the esterification for up to ten consecutive runs. This journal is
Tunable aryl imidazolium ionic liquids (TAIILs) as environmentally benign catalysts for the esterification of fatty acids to biodiesel fuel
Ho, Wen-Yueh,Lin, Wesley,Lin, Yi-Jyun,Luo, Shun-Yuan,Pantawane, Amit,Su, Po-Fang,Thul, Mayur,Tseng, Shao-An,Wu, Hsin-Ru
, (2020/12/02)
Herein, we describe the synthesis of tunable aryl imidazolium ionic liquid catalysts and tested for esterification of fatty acids to biodiesel. In this work, six tunable aryl imidazolium ionic liquids (TAIILs) 1a-1f were prepared. These ionic liquids were used as the economical and reusable catalysts for the synthesis of biodiesel fuels. The reaction has been preceded in a monophase at 80 °C for 4 h, after which the product was separated from the catalyst system by a simple liquid/liquid phase separation at room temperature with excellent yields. With the simple post-process, the catalyst is reusable at least 6 times. This novel method offers a short reaction time, good yields, and environmentally benign characteristics.
Hybrid Nanocomposites Formed by Lanthanide Nanoparticles in Zr-MOF for Local Temperature Measurements during Catalytic Reactions
Jena, Himanshu Sekhar,Rijckaert, Hannes,Krishnaraj, Chidharth,Van Driessche, Isabel,Van Der Voort, Pascal,Kaczmarek, Anna M.
, p. 8007 - 8017 (2021/10/25)
Zr-metal organic frameworks (MOFs) are water-stable materials with high surface properties and chemical stabilities and are often employed for catalysis. They can also become hosts for various upconverting nanoparticles via self-assembly, which opens up possibilities to use such nanocomposite materials for combined catalysis-thermometry applications. In our work, we show that the NaGdF4:Er,Yb@UiO-66-NH2, NaGdF4:Tm,Yb@UiO-66-NH2, and NaYF4:Er,Yb@NaYF4@UiO-66-NH2 nanocomposite materials display excellent temperature-dependent luminescence properties. Additionally, these nanocomposite materials can perform as a stable and reusable catalyst for the esterification of lauric acid (biomass-derived free fatty acid) with methanol to obtain methyl laurate. The NaGdF4/NaYF4 nanoparticles incorporated in the MOF do not significantly decrease their catalytic performance. At the same time, photoluminescence measurements can be performed in a working catalytic environment and the temperature can be read out from the ratio of the 2H11/2 and 4S3/2 transition peaks of Er3+ or 3F3 and 3H4 transition peaks of Tm3+ from the nanocomposites. The correlation between temperature, luminescent intensities, and catalytic reactivity was studied and showed that all the three factors depend on each other, but do not interfere. To the best of our knowledge, the combination of catalysis and luminescence thermometry in a MOF hybrid material has not been reported to date. However, it opens a wide range of possibilities, keeping in mind the large and versatile number of MOFs as well as different thermometry systems that can be incorporated into inorganic nanoparticles.
