111-11-5Relevant articles and documents
Malononitrile as acylanion equivalent
F?rster, Sebastian,Tverskoy, Olena,Helmchen, Günter
, p. 2803 - 2806 (2008)
The oxidation of derivatives of malononitrile with peracid in methanol proceeds with loss of the cyano groups to yield methyl esters in high yield. The method was applied to a variety of malononitrile derivatives, some of which were prepared by Pd- or Ir-catalyzed asymmetric allylic substitution. Georg Thieme Verlag Stuttgart.
Structure and catalysis of layered Nb-W oxide constructed by the self-assembly of nanofibers
Okumura, Kazu,Ishida, Soichiro,Takahata, Ryota,Katada, Naonobu
, p. 197 - 203 (2013)
Treatment of crystalline Nb2O5-WOx fibers with an aqueous solution of oxalic or tartaric acid resulted in the formation of nanosheets with a layered structure in which fibers were self-assembled. The oxalic and tartaric acid-treated oxides had dense layered structures containing mesopores between the layers with mean diameters of 4.6 and 1.9 nm, respectively. These oxides exhibited much higher recyclability as catalysts for the Friedel-Crafts alkylation and acylation of anisole compared to untreated ones. Furthermore, no deactivation was observed in a continuous flow process for the reaction of anisole and benzyl alcohol at least over 87 days' period in which turnover number = 33,000 was obtained. The improved catalytic performance was ascribed to the formation of layered structure, which was preserved during reactions.
Synthesis, characterization and reactivity of (dithiolato)indium complexes
Anderson, Timothy S.,Briand, Glen G.,Brüning, Ralf,Decken, Andreas,Margeson, Matthew J.,Pickard, Heidi M.,Trevors, Eric E.
, p. 101 - 108 (2017)
We have synthesized indium complexes incorporating tetradentate dithiolate ligands. The 1:1 reaction of InX3 (X?=?OAc, NO3) and the corresponding dithiol or dithiolate yielded the compounds [(SOOS)In(py)(NO3)] (1), [(SNNS)In(OAc)] (2), [In(μ-SNNS)2(μ-OMe)In][NO3] (3), [(SNNSPr)In(OAc)] (4), [(NNS2)In(OAc)] (5) and [(NNS2)In(NO3)] (6) [H2(SOOS)?=?2,2′-(ethylenedioxy)diethanethiol; H2(SNNS)?=?N,N′-dimethyl-N,N′-bis(2-mercaptoethyl)ethylenediamine; H2(SNNSPr)?=?N,N′-diethyl-N,N′-bis(2-mercaptoethyl)propanediamine; H2(NNS2)?=?N,N-diethyl-N′,N′-bis(2-mercaptoethyl)ethanediamine]. The solid-state structures of 1, 2 and 4–6 are mononuclear and show a tetradentate SOOS/SNNS/NNS2 ligand and a distorted octahedral (1) or trigonal bipyramidal (2, 4–6) coordination geometry at indium. Compound 3 is dinuclear, with the indium centres bridged by a -OMe oxygen atom and a thiolate sulfur atom of chelating tetradentate ligands, respectively. InX3 (X?=?Cl, NO3) were found to be useful Lewis acid catalysts for the aldol reaction of benzaldehyde and 1-(trimethylsiloxy)cyclohexene under ambient conditions, while compounds 1–6 show moderate activity as catalysts for the esterification of stearic acid and transesterification of methyl stearate and glyceryl trioctanoate.
(BDP)CuH: A "hot" Stryker's reagent for use in achiral conjugate reductions
Baker, Benjamin A.,Boskovic, Zarko V.,Lipshutz, Bruce H.
, p. 289 - 292 (2008)
(Chemical Equation Presented) A ligand-modified, economical version of Stryker's reagent (SR) has been developed based on a bidentate, achiral bis-phosphine. Generated in situ, "(BDP)CuH" smoothly effects conjugate reductions of a variety of unsaturated substrates, including those that are normally unreactive toward SR. Substrate-to-ligand ratios typically on the order of 1000-10000:1 can be used leading to products in high yields.
Pore-expanded SBA-15 sulfonic acid silicas for biodiesel synthesis
Dacquin,Lee,Pirez,Wilson
, p. 212 - 214 (2012)
Here we present the first application of pore-expanded SBA-15 in heterogeneous catalysis. Pore expansion over the range 6-14 nm confers a striking activity enhancement towards fatty acid methyl ester (FAME) synthesis from triglycerides (TAG), and free fatty acid (FFA), attributed to improved mass transport and acid site accessibility.
Friedel-Crafts acylation of anisole with octanoic acid over acid modified zeolites
Bai, Guoyi,Han, Jie,Zhang, Huanhuan,Liu, Chen,Lan, Xingwang,Tian, Fei,Zhao, Zhen,Jin, Hui
, p. 27116 - 27121 (2014)
Friedel-Crafts acylation of anisole using octanoic acid as a green acylating agent was studied over zeolites free of solvent. It was found that a mixed organic acid, composed of tartaric acid and oxalic acid, modified Hβ (Mix-Hβ) zeolite showed the best catalytic performance among the catalysts studied. The conversion of octanoic acid and the selectivity for p-octanoyl anisole were 72.7% and 82.5%, respectively. Inductively coupled plasma analysis (ICP) and 27Al MAS NMR indicated dealumination of the parent Hβ zeolite due to the treatment of the mixed organic acid, leading to more accessible active sites and accounting for the better catalytic activity of the Mix-Hβ zeolite. Furthermore, lower strength of Lewis acid sites and Broensted acid sites of the Mix-Hβ zeolite, as demonstrated by Fourier Transform Infrared Spectrometry after adsorption of pyridine (Py-IR), are advantageous to suppress the demethylation of anisole and the subsequent esterification of thus formed phenol, accounting for its higher selectivity toward p-octanoyl anisole.
Graphite oxide activated zeolite NaY: Applications in alcohol dehydration
Todd, Alexander D.,Bielawski, Christopher W.
, p. 135 - 139 (2013)
A mixture of graphite oxide (GO) and the zeolite NaY (Si/Al = 5.1) was used to dehydrate various alcohols to their respective olefinic products. Using conditions optimized for 4-heptanol (15 wt% GO-NaY (1 : 1 wt/wt), 150°C, 30 min), a series of secondary and tertiary aliphatic alcohols were cleanly dehydrated in moderate to excellent conversions (27.5-97.2%). Several primary alcohols were also dehydrated, although higher catalyst loadings (200 wt% GO-NaY (1 : 1) and longer reaction times (3 h) were required. The enhanced dehydration activity was attributed to the ability of GO to convert NaY to an acidic form and without the need for ammonium cation exchange and/or high temperature calcination. The Royal Society of Chemistry 2013.
Aerobic oxidative esterification of 5-hydroxymethylfurfural to dimethyl furan-2,5-dicarboxylate by using homogeneous and heterogeneous PdCoBi/C catalysts under atmospheric oxygen
Li, Feng,Li, Xing-Long,Li, Chuang,Shi, Jing,Fu, Yao
, p. 3050 - 3058 (2018)
The conversion of platform molecule 5-hydroxymethylfurfural (HMF) into many value-added derivatives has attracted significant interest. FDCA and its esters are important derivatives of HMF, which can be used as polyester monomers and pharmaceutical intermediates. In this paper, oxidative esterification of 5-HMF has been carried out by using homogeneous and heterogeneous PdCoBi/C catalysts under atmospheric oxygen. The effect of reaction conditions on product distribution has been studied under both homogeneous and heterogeneous catalytic conditions. The highest yields of oxidative esterification products are obtained at 93% and 96% by using homogeneous and heterogeneous PdCoBi/C catalysts, respectively. The catalysts are characterized by X-ray photoelectron spectroscopy (XPS) and powder X-ray diffraction (XRD). The catalytic system has better compatibility according to the expansion of the substrate. A reaction mechanism is proposed, and recycle experiments are also conducted.
Syntheses of novel halogen-free Br?nsted-Lewis acidic ionic liquid catalysts and their applications for synthesis of methyl caprylate
Han, Xiao-Xiang,Du, Huan,Hung, Chin-Te,Liu, Li-Li,Wu, Pei-Hao,Ren, Da-Hai,Huang, Shing-Jong,Liu, Shang-Bin
, p. 499 - 508 (2015)
A series of benign halogen-free ionic liquid (IL) catalysts were synthesized by combining the Br?nsted acidic ionic liquid [HSO3-pmim]+HSO4? with ZnO in different composition ratios. The IL catalysts, which possess both Br?nsted and Lewis acidities, were employed as acidic catalysts for the esterification of n-caprylic acid to methyl caprylate. The [HSO3-pmim]+(1/2Zn2+)SO42?, prepared by cooperating equimolar amounts of Br?nsted and Lewis acid sites, was found to exhibit an optimal catalytic performance and excellent durability. This is attributed to a synergy of Br?nsted and Lewis acidities manifested by the catalyst. The response surface methodology (RSM) based on the Box-Behnken design (BBD) was utilized to explore the effects of different experimental variables (viz. catalyst amount, methanol to caprylic acid molar ratio, temperature, and reaction time) on the esterification reaction. Analysis of variance (ANOVA) was also employed to study the interactions between variables and their effects on the catalytic process. Accordingly, the deduced optimal reaction conditions led to a high methyl caprylate yield of 95.4%, in good agreement with experimental results and those predicted by the BBD model. Moreover, a kinetic study performed under optimal reaction conditions revealed an apparent reaction order of 1.70 and an active energy of 33.66 kJ mol?1
Ozonolysis of methyl oleate monolayers at the air-water interface: Oxidation kinetics, reaction products and atmospheric implications
Pfrang, Christian,Sebastiani, Federica,Lucas, Claire O. M.,King, Martin D.,Hoare, Ioan D.,Chang, Debby,Campbell, Richard A.
, p. 13220 - 13228 (2014)
Ozonolysis of methyl oleate monolayers at the air-water interface results in surprisingly rapid loss of material through cleavage of the CC bond and evaporation/dissolution of reaction products. We determine using neutron reflectometry a rate coefficient of (5.7 ± 0.9) × 10-10 cm2 molecule-1 s-1 and an uptake coefficient of ～3 × 10-5 for the oxidation of a methyl ester monolayer: the atmospheric lifetime is ～10 min. We obtained direct experimental evidence that a minor change to the structure of the molecule (fatty acid vs. its methyl ester) considerably impacts on reactivity and fate of the organic film.
Alkali- and nitrate-free synthesis of highly active Mg-Al hydrotalcite-coated alumina for FAME production
Creasey, Julia J.,Chieregato, Alessandro,Manayil, Jinesh C.,Parlett, Christopher M. A.,Wilson, Karen,Lee, Adam F.
, p. 861 - 870 (2014)
Mg-Al hydrotalcite coatings have been grown on alumina via a novel alkali- and nitrate-free impregnation route and subsequent calcination and hydrothermal treatment. The resulting Mg-HT/Al2O3 catalysts significantly outperform conventional bulk hydrotalcites prepared via co-precipitation in the transesterification of C4-C18 triglycerides for fatty acid methyl ester (FAME) production, with rate enhancements increasing with alkyl chain length. This promotion is attributed to improved accessibility of bulky triglycerides to active surface base sites over the higher area alumina support compared to conventional hydrotalcites wherein many active sites are confined within the micropores.
Sterically hindered (pyridyl)benzamidine palladium(II) complexes: Syntheses, structural studies, and applications as catalysts in the methoxycarbonylation of olefins
Akiri, Saphan O.,Ojwach, Stephen O.
, (2021/09/09)
Reactions of ligands (E)-N′-(2,6-diisopropylphenyl)-N-(4-methylpyridin-2-yl)benzimidamide (L1), (E)-N′-(2,6-diisopropylphenyl)-N-(6-methylpyridin-2-yl)benzimidamide (L2), (E)-N′-(2,6-dimethylphenyl)-N-(6-methylpyridin-2-yl)benzimidamide (L3), (E)-N′-(2,6-dimethylphenyl)-N-(4-methylpyridin-2-yl)benzimidamide (L4), and (E)-N-(6-methylpyridin-2-yl)-N′-phenylbenzimidamide (L5) with [Pd(NCMe)2Cl2] furnished the corresponding palladium(II) precatalysts (Pd1–Pd5), in good yields. Molecular structures of Pd2 and Pd3 revealed that the ligands coordinate in a N^N bidentate mode to afford square planar compounds. Activation of the palladium(II) complexes with para-tolyl sulfonic acid (PTSA) afforded active catalysts in the methoxycarbonylation of a number of alkene. The resultant catalytic activities were controlled by the both the complex structure and alkene substrate. While aliphatic substrates favored the formation of linear esters (>70%), styrene substrate resulted in the formation of predominantly branched esters of up to 91%.
Esterification or Thioesterification of Carboxylic Acids with Alcohols or Thiols Using Amphipathic Monolith-SO3H Resin
Ichihara, Shuta,Ishida, Moeka,Ito, Ryo,Kato, Ayumu,Monguchi, Yasunari,Nakamura, Shinji,Park, Kwihwan,Sajiki, Hironao,Takada, Hitoshi,Wakayama, Fumika,Yamada, Tsuyoshi,Yamada, Yutaro
, p. 2702 - 2710 (2022/01/19)
We have developed a method for the esterification of carboxylic acids with alcohols using amphipathic, monolithic-resin bearing sulfonic acid moieties as cation exchange functions (monolith-SO3H). Monolith-SO3H efficiently catalyzed the esterification of aromatic and aliphatic carboxylic acids with various primary and secondary alcohols (1.55.0 equiv) in toluene at 6080 °C without the need to remove water generated during the reaction. The amphipathic property of monolith-SO3H facilitates dehydration due to its capacity for water absorption. This reaction was also applicable to thioesterification, wherein the corresponding thioesters were obtained in excellent yield using only 2.0 equiv of thiol in toluene, although heating at 120 °C was required. Moreover, monolith-SO3H was separable from the reaction mixtures by simple filtration and reused for at least five runs without decreasing the catalytic activity.
