- Catalytic synthesis of butyl isovalerate by br?nsted acidic ionic liquid under microwave irradiation
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Butyl isovalerate was synthesized from isovaleric acid and butanol with ionic liquid as catalysts under microwave irradiation. The systematic study was investigated including of the effects of molar ratio of acid to alcohol, microwave power, amount of catalyst, microwave time and microwave temperature on the process. The optimum operation conditions were as follows: n(butanol):n(isovaleric acid) = 1.6:1, microwave power 500 W, amount of catalyst of 6 wt % to isovaleric acid, microwave time of 0.5 h and microwave temperature of 110 °C. The yield of butyl isovalerate could reach 92.1 % under the optimal operation conditions mentioned above. The excellent durability and recycle ability of ionic liquids were also addressed even after five times reused.
- Du, Huan,He, Yanfei,Tan, Zhongqin,Han, Xiaoxiang
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- Nickel-catalyzed direct alkylation of heterocycles with α-bromo carbonyl compounds: C3-selective functionalization of 2-pyridones
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Nickel HAS it: A Ni(cod)2/dppp catalyst system promotes the direct alkylation of electron-rich heterocycles with α-bromo carbonyl compounds and involves an alkyl radical intermediate (see scheme; cod=1,5-cyclooctadiene, dppp=1,3-bis(diphenylphosphino)propane). This homolytic radical aromatic substitution (HAS)-type reaction enables the C3-selective direct functionalization of 2-pyridones. Copyright
- Nakatani, Akihiro,Hirano, Koji,Satoh, Tetsuya,Miura, Masahiro
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- Quarternary Ammonium Salts for Butylation and Mass Spectral Identification of Volatile Organic Acids
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The esterification method described by Greeley (J.Chromatogr. 1974, 88, 229) was modified to overcome the problem of volatile acid evaporation during sample workup procedures.After solvent extraction from an aqueous sample, the acids were converted to their butyl ester derivatives in a two step process.Firstly, an involatile quarternary ammonium salts was formed which allowed concentration by solvent evaporation without loss of volatile acids.The acid salts were then converted to butyl esters by heating in the presence of n-butyl bromide and the esters were separated on a support- coated open tabular (SCOT) OV17 capillary column.The recovery and butylation yield were shown to be quantitative for isobutyric acid and the linearities and limits of detection are given for the five C4-C5 aliphatic acids.The mass spectra of butyl esters contain abundant rearrangement ions not present in methyl, ethyl, trimethylsilyl, or aryl esters which enable their rapid identification.The method was applied to the analysis of volatile urinary acids from a patient with Maple Syrup Urine Disease and showed conclusively the presence of both 2-methylbutyric and isovaleric acids.
- Burke, Daniel G.,Halpern, Berthold
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- Nematicidal activity of natural ester compounds and their analogues against pine wood nematode, bursaphelenchus xylophilus
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In this study, we evaluated the nematicidal activity of natural ester compounds against the pine wood nematode, Bursaphelenchus xylophilus, to identify candidates for the development of novel, safe nematicides. We also tested the nematicidal activity of synthesized analogues of these ester compounds to determine the structure-activity relationship. Among 28 ester compounds tested, isobutyl 2-methylbutanoate, 3-methylbutyl 2-methylbutanoate, 3-methylbutyl tiglate, 3-methyl-2-butenyl 2- methylbutanoate, and pentyl 2-methylbutanoate showed strong nematicidal activity against the pine wood nematode at a 1 mg/ mL concentration. The other ester compounds showed weak nematicidal activity. The LC50 values of 3-methylbutyl tiglate, isobutyl 2-methylbutanoate, 3-methylbutyl 2-methylbutanoate, 3-methyl-2-butenyl 2-methylbutanoate, and pentyl 2- methylbutanoate were 0.0218, 0.0284, 0.0326, 0.0402, and 0.0480 mg/mL, respectively. The ester compounds described herein merit further study as potential nematicides for pine wood nematode control.
- Seo, Seon-Mi,Kim, Junheon,Koh, Sang-Hyun,Ahn, Young-Joon,Park, Il-Kwon
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p. 9103 - 9108
(2015/03/14)
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- Hydroalkoxycarbonylation of olefins in the presence of palladium phosphine complexes: High activity and regioselectivity
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Several types of catalyst systems were examined in the olefin hydroalkoxycarbonylation reaction. The systems contained Pd(PPh 3)4, PdCl2(PPh3)2, or some other palladium compounds as a principal component. The second component (promoter) was p-toluenesulfonic acid or diphenyl(m-sulfophenyl)phosphine, which combines both the ligand and promoter functions. An important feature of these systems is their high activity in the hydroalkoxycarbonylation of ethylene and a high regioselectivity (83-100%) in the hydroalkoxycarbonylation of α-olefins with respect to linear products. Thus, it was unnecessary to introduce additional stabilizing ligands to augment the catalyst and promoter. The esters obtained can find application in the pharmaceutical industry and perfumery, as well as in other industries. Nauka/Interperiodica 2006.
- Chepaikin,Bezruchenko,Suerbaev,Shalmagambetov
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p. 117 - 121
(2007/10/03)
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- Structure-function correlation in lipase catalysed esterification reactions of short and medium carbon chain length alcohols and acids
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An attempt has been made to correlate the carbon chain lengths of acids and alcohols to the extent of esterification in the Rhizomucor miehei lipase catalyzed esterification reactions involving acids of carbon chain length C2-C5 and alcohols of carbon chain length C1-C8.
- Divakar, Soundar
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p. 1919 - 1922
(2007/10/03)
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