106-33-2Relevant academic research and scientific papers
Surfactant-like Br?nsted acidic ionic liquid as an efficient catalyst for selective Mannich reaction and biodiesel production in water
Vafaeezadeh, Majid,Karbalaie-Reza, Mina,Hashemi, Mohammad Mahmoodi,Soleimany, Kasra Qasempour
, p. 907 - 914 (2017)
Abstract: The current study deals with the applications of a surfactant-like Br?nsted acidic ionic liquid (IL) 1-dodecyl-3-methylimidazolium hydrogen sulfate ([DMIm]HSO4) for Mannich reaction at room temperature. The reaction was efficiently preceded in water as solvent without using any harmful and expensive organic additives. Our findings showed that the reaction is selective for cyclohexanone and no Mannich product was observed when cyclopentanone was used as starting material. Density functional theory (DFT) calculations were performed to provide an evidence about the nature of reactivity of the cyclohexanone/cyclopentanone. The activity of the catalyst was also tested for biodiesel production of fatty acids with methanol and ethanol at mild thermal condition without applying additional water removal steps such as using additives or performing special methodologies like azeotropic distillation. In both reactions, the IL can be recycled and reused several times with relatively constant efficiency. Graphical Abstract: [Figure not available: see fulltext.]
PS-SO3H@phenylenesilica with yolk-double-shell nanostructures as Efficient and stable solid acid catalysts
Zhang, Xiaomin,Zhao, Yaopeng,Yang, Qihua
, p. 180 - 188 (2014)
Efficient and stable solid acids have been successfully synthesized by sulfonation of polystyrene (PS) in the hollow interiors of silica-based hollow nanostructures. It was found that larger and smaller inner void spaces result in the formation of PS-SO3H@phenylenesilica respectively with double-shell (DSNs) and yolk-double-shell nanostructure (YDSNs). PS-SO3H@phenylenesilica with DSNs and YDSNs nanostructure shows comparable activity and is more active than Amberlyst-15 in the esterification reaction. PS-SO3H@phenylenesilica with YDSNs nanostructure affords higher activity than that with DSNs nanostructure in the Friedel-Crafts alkylation of toluene with 1-hexene, which is mainly attributed to the fact that the unique YDSNs nanostructure could slow down the swelling rate of PS-SO3H during the catalytic process. More importantly, PS-SO3H@phenylenesilica with YDSNs nanostructure showed much higher recycle stability than Amberlyst-15 in the Friedel-Crafts alkylation of toluene with 1-hexene, probably due to the high thermal stability of the sulfonic acid group and the unique YDSNs nanostructure.
A study on the catalytic activity and theoretical modeling of a novel dual acidic mesoporous silica
Vafaeezadeh, Majid,Fattahi, Alireza
, p. 16647 - 16654 (2014)
A novel mesoporous silica-functionalized dual Bronsted acidic species has been introduced as an efficient catalyst for solvent-free esterification of fatty acids with ethanol. The structure of the catalyst has been characterized by FT-IR spectroscopy, thermal gravimetric analysis (TGA), TEM and N2 adsorption-desorption. TGA of catalyst 1 showed no weight loss before 200 °C, indicating a high degree of hydrophobicity of the surface of the mesoporous silica. TEM images and nitrogen adsorption-desorption showed no noticeable changes to the structure of the catalyst before and after acid treatment. pH metric analysis was performed for the catalyst to determine the loading of the acidic sites. The structure of the catalyst was modeled by mimicking the surface of functionalized silica gel in the form of a cage-like cluster. Various conformers from the proposed structures were selected and optimized at the B3LYP/6-311++G** level of calculation. Natural bond orbital (NBO) analysis was performed to investigate the nature of hydrogen bonding of the catalyst in more detail. Based on the data gained from the optimized structures of the catalyst, a mechanism was proposed for the esterification reaction.
Competition balance between mesoporous self-assembly and crystallization of zeolite: A key to the formation of mesoporous zeolite
Li, Hua,Wu, Huazhong,Shi, Jian-Lin
, p. 71 - 78 (2013)
A hierarchical meso-/microporous aluminosilicate has been synthesized through kinetic control over the competition balance between mesoporous self-assembly and microporous zeolite crystallization by using hexadecyl trimethyl ammonium bromide (CTAB) and tetrabutylammonium hydroxide (TBAOH) as meso- and micro-porogens, respectively. A very small pH value range of 11.10-11.30, which can be well tuned by added ethanol volume fraction and/or NaOH addition, was found to be suitable for the formation of mesoporous zeolite without phase separation. Balanced inorganic species adsorptions onto the meso- and microtemplates, and the subsequent electrostatic interaction between such adsorption-formed meso- and micro-colloids are discussed and proposed to be the two key underlined mechanisms in the successful synthesis. The material shows perfect crystallization of zeolite frameworks and relatively high surface area and meso-/micropore volumes. The prepared mesoporous zeolite showed much higher catalytic activity in the reaction between lauric acid and ethanol than those when using both amorphous mesoporous materials and conventional ZSM-5 zeolite as catalysts.
Cross-Coupling between Functionalized Alkylcopper Reagents and Functionalyzed Alkyl Halides
Tucker, Charles E.,Knochel, Paul
, p. 4781 - 4782 (1993)
Functionalized dialkylzincs treated with Me2Cu(CN)(MgCl)2 in DMPU undergo highly chemoselective cross-coupling reactions with functionalized alkyl iodides or benzylic bromides providing polyfunctional products in good to excellent yields.
The nanocomposites of SO3H-hollow-nanosphere and chiral amine for asymmetric aldol reaction
Gao, Jinsuo,Liu, Jian,Bai, Shiyang,Wang, Peiyuan,Zhong, Hua,Yang, Qihua,Li, Can
, p. 8580 - 8588 (2009)
The nanocomposites formed by SO3H-hollow-nanospheres and chiral amines are highly efficient catalysts for the direct asymmetric aldol reaction of cyclohexanone and 4-nitrobenzaldehyde. The catalyst showed 91% yield with 96% ee under optimized reaction conditions. SO3H-hollow-nanospheres were synthesized by oxidation of thiol-hollow-nanospheres, which were fabricated through a one-pot co-condensation of 1,2-bis(trimethoxysilyl)ethane and 3-mercaptopropyltrimethoxysilane around F127 micelles in the presence of NaOAc. Chiral amines could be combined with SO3H-hollow-nanospheres through facile electrostatic interactions. The obtained nanocomposites showed a much higher reaction rate than the catalyst formed from the combination of chiral amine and SO3H-mesoporous-organosilica (ribbon shaped particles with particle size of tens of micrometres) in the direct asymmetric aldol reaction. This is mainly attributed to the hollow spherical morphology and nano-scale particle size (16-20 nm) of the SO3H-hollow-nanospheres. The Royal Society of Chemistry 2009.
Effective transesterification of triglyceride with sulphonated modified SBA-15 (SBA-15-SO3H): Screening, process and mechanism
Hu, Ningmeng,Kong, Zhaoni,He, Liang,Ning, Ping,Gu, Junjie,Miao, Rongrong,Sun, Xiangqian,Guan, Qingqing,Duan, Peigao
, p. 846 - 853 (2018)
Different morphologies of ZrO2 were produced by different templates: ZrO2(CaCO3), ZrO2(C12H25SO3Na), ZrO2(C12H25SO4Na), ZrO2(CTAB), and solid superacids, such as ZrO2/SBA-15, SO42-/ZrO2, SO42-/ZrO2/SBA-15, and SBA-15-SO3H. The catalytic transesterification activities of these catalysts were tested. The more highly acidic catalysts and higher surface areas led to higher catalytic activity. In particular, the conversion yield of triglyceride reached 90.1% and was maintained for 90 min at 200 °C with 5.0 wt% SBA-15-SO3H, indicating this material to be one of most effective acid catalysts for the transesterification process. The mechanism indicated that the most important process was the abstraction of hydrogen from alcohols and α-substituted carboxylic glycerides. In the initial transesterification, the alcohol hydrogen atoms could be attracted onto the surface. Then, the nucleophilic attack of the alcohol led to the α-substituted carboxylic glyceride. Finally, monoglycerides, diglycerides or glycerine were released from the surface by proton (H+) replacement.
Lipase activity and enantioselectivity of whole cells from a wild-type Aspergillius flavus strain
Solarte, Carmen,Yara-Varon, Edinson,Eras, Jordi,Torres, Merce,Balcells, Merce,Canela-Garayoa, Ramon
, p. 78 - 83 (2014)
This study reports the high enantiomeric preference of whole cell lipase from Aspergillus flavus wild-type that allows the preparation of a chiral secondary alcohol. Whole cells prepared from a wild-type Aspergillus flavus strain were used as biocatalysts to prepare (R)-1-phenylethyl acetate. (R)-1-Phenylethanol was esterified into (R)-1-phenylethyl acetate with a 94.6% enantiomeric excess (ee) within 24 h at 40 C and (S)-1-phenylethanol remained in the reaction medium with a >99%ee. Besides, this biocatalyst allows the preparation of ethyl laurate and a mixture of 2-chloro-1-(chloromethyl)ethyl acrylate and 2,3-dichloro-1-propyl acrylate. The ethyl laurate yield was 96%, whereas the synthesis of a mixture of the acrylate regioisomers, 2-chloro-1-(chloromethyl)ethyl acrylate and 2,3-dichloro-1-propyl acrylate gave similar yields to those obtained using commercial lipases.
Efficient and stable PS-SO3H/SiO2 hollow nanospheres with tunable surface properties for acid catalyzed reactions
Chen, Jingjing,Chen, Jian,Zhang, Xiaomin,Gao, Jinsuo,Yang, Qihua
, p. 1 - 8 (2016)
Facile synthesis of hybrid solid acids with finely engineered surface properties was successfully realized via sulfonation of polystyrene (PS) dispersed in nanopores of silica hollow nanosphere modified with different organic group. It was found that octyl or perfluorinated octyl could efficiently increase the surface hydrophobicity of the hybrid solid acids. Benefited from the facile adjustability of the surface properties, the catalytic performance of the solid acids could be readily improved in both the esterification of lauric acid with ethanol and the transterification between tripalmitin and methanol. The solid acid modified with perfluorinated octyl shows even higher activity than liquid sulfuric acid in the transesterification reaction. The octyl group incorporated in the silica shell could also prevent the leaching of PS-SO3H during the catalytic process.
Medium-chain fatty acids from Eugenia winzerlingii leaves causing insect settling deterrent, nematicidal, and phytotoxic effects
Cruz-Estrada, Angel,Ruiz-Sánchez, Esaú,Cristóbal-Alejo, Jairo,González-Coloma, Azucena,Andrés, María Fe,Gamboa-Angulo, Marcela
, (2019)
Eugenia winzerlingii (Myrtaceae) is an endemic plant from the Yucatan peninsula. Its organic extracts and fractions from leaves have been tested on two phloem-feeding insects, Bemisia tabaci and Myzus persicae, on two plant parasitic nematodes, Meloidogyne incognita and Meloidogyne javanica, and phytotoxicity on Lolium perenne and Solanum lycopersicum. Results showed that both the hexane extract and the ethyl acetate extract, as well as the fractions, have strong antifeedant and nematicidal effects. Gas chromatography-mass spectrometry analyses of methylated active fractions revealed the presence of a mixture of fatty acids. Authentic standards of detected fatty acids and methyl and ethyl derivatives were tested on target organisms. The most active compounds were decanoic, undecanoic, and dodecanoic acids. Methyl and ethyl ester derivatives had lower effects in comparison with free fatty acids. Dose-response experiments showed that undecanoic acid was the most potent compound with EC50 values of 21 and 6 nmol/cm2 for M. persicae and B. tabaci, respectively, and 192 and 64 nmol for M. incognita and M. javanica, respectively. In a phytotoxicity assay, medium-chain fatty acids caused a decrease of 38-52% in root length and 50-60% in leaf length of L. perenne, but no effects were observed on S. lycopersicum. This study highlights the importance of the genus Eugenia as a source of bioactive metabolites for plant pest management.
