616-44-4Relevant articles and documents
Method for separating components in mixture containing methylbenzene, 2-methylthiophene and 3-methylthiophene
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Paragraph 0052; 0056; 0057; 0058, (2019/12/09)
The invention belongs to the technical field of chemical engineering, and particularly relates to a method for separating components in a mixture containing methylbenzene, 2-methylthiophene and 3-methylthiophene. According to the method, 2-methylthiophene and 3-methylthiophene in the mixture containing methylbenzene, 2-methylthiophene and 3-methylthiophene with very close boiling points are converted into substances 2-chloro-5-methylthiophene and 2,5-dichloro-3-methylthiophene with boiling points greatly different from the boiling point of methylbenzene by adopting a chemical method for the first time; then the components are separated and purified by adopting a rectification method, and the 2-chloro-5-methylthiophene and the 2,5-dichloro-3-methylthiophene are treated by adopting a reduction method and the like to obtain single-component 2-methylthiophene and 3-methylthiophene, so that the methylbenzene, the 2-methylthiophene and the 3-methylthiophene are separated. The method is simple in process, high in product yield and purity, good in separation effect, low in energy consumption and free of emission of three wastes(waste gas, waste water and industrial residues), and is a green separation process.
Catalytic Synthesis of Methylthiophenes
Mashkina,Khairulina
, p. 1794 - 1797 (2019/03/26)
The gas-phase reaction of dimethyl disulfide with thiophene over Co/HZSM-5 catalyst in a helium medium under atmospheric pressure at 250–350°C gave a mixture of mono-, di-, tri-, and tetramethylthiophenes with an overall selectivity of 94–96%.
Preparation of an Arenylmethylzinc Reagent with Functional Groups by Chemoselective Cross-Coupling Reaction of Bis(iodoazincio)methane with Iodoarenes
Shimada, Yukako,Haraguchi, Ryosuke,Matsubara, Seijiro
, p. 2395 - 2398 (2015/10/19)
Palladium-catalyzed cross-coupling reaction of bis(iodozincio)methane with iodoarenes carrying various functionalities such as ester, boryl, cyano, and halo groups proceeded chemoselectively to give the corresponding arenylmethylzinc species efficiently. The moderate reactivity of the gem-dizinc reagent imparted functional group tolerance to the process. The transformations from iodoheteroarenes were also performed; in the case of iodopyridine derivatives, the nickel-catalyzed reaction gave the corresponding organozinc species efficiently. The obtained arenylmethylzinc species underwent the copper-mediated coupling reaction with a range of organic halides.
Hydrodecarboxylation of Carboxylic and Malonic Acid Derivatives via Organic Photoredox Catalysis: Substrate Scope and Mechanistic Insight
Griffin, Jeremy D.,Zeller, Mary A.,Nicewicz, David A.
supporting information, p. 11340 - 11348 (2015/09/21)
A direct, catalytic hydrodecarboxylation of primary, secondary, and tertiary carboxylic acids is reported. The catalytic system consists of a Fukuzumi acridinium photooxidant with phenyldisulfide acting as a redox-active cocatalyst. Substoichiometric quantities of Hünigs base are used to reveal the carboxylate. Use of trifluoroethanol as a solvent allowed for significant improvements in substrate compatibilities, as the method reported is not limited to carboxylic acids bearing α heteroatoms or phenyl substitution. This method has been applied to the direct double decarboxylation of malonic acid derivatives, which allows for the convenient use of dimethyl malonate as a methylene synthon. Kinetic analysis of the reaction is presented showing a lack of a kinetic isotope effect when generating deuterothiophenol in situ as a hydrogen atom donor. Further kinetic analysis demonstrated first-order kinetics with respect to the carboxylate, while the reaction is zero-order in acridinium catalyst, consistent with another finding suggesting the reaction is light limiting and carboxylate oxidation is likely turnover limiting. Stern-Volmer analysis was carried out in order to determine the efficiency for the carboxylates to quench the acridinium excited state.
User-friendly methylation of aryl and vinyl halides and pseudohalides with DABAL-Me3
Cooper, Thea,Novak, Andrew,Humphreys, Luke D.,Walker, Matthew D.,Woodward, Simon
, p. 686 - 690 (2007/10/03)
An extremely technically simple cross-methylation of aryl and vinyl halides and pseudohalides using an air-stable adduct of trimethylaluminium with a Pd(0) catalyst supported by commercially available biarylphosphines gives excellent yields of methylated products (mainly > 95%). Reactions can be run with either 0.5 mol% catalyst or without requiring the exclusion of atmospheric oxygen or the drying of solvents in some cases. A wide variety of functional groups is tolerated including CN, OH, CO2R, CHO and NO2.
Catalytic transformations of alkylthiophenes
Mashkina,Chernov
, p. 209 - 215 (2007/10/03)
The transformations of alkylthiophenes in the presence of amorphous aluminosilicate and decationated zeolite HNaY were studied. Substituted thiophenes with R = 2- and 3-Me, 2-Et, and 2-iso-Pr undergo dealkylation to thiophene with close rates, migration of the alkyl group from the 9α- to the β-position of the thiophene ring (or in the opposite direction with an elevated rate), and decomposition with H2S elimination. The dealkylation rate of 2-substituted thiophenes with a branched-chain radical (R = iso-Pr, terf-Bu) is much higher and the elimination rate with this radical is lower than those for normal-chain radicals; the isomerization step is virtually absent. Di-, tri-, and tetrasubstituted thiophenes with R = Et and iso-Pr undergo stepwise dealkylation, which is facilitated by an increase in the degree of substitution on the thiophene ring. Thiophene and its lower homologues can be obtained by the transformation of a mixture of high-molecular thiophenes. Copyright
Synthesis of tungsten thienyl complexes via C-H bond activation of thiophenes
Sakaba, Hiroyuki,Yumoto, Takahiro,Watanabe, Sanae,Kabuto, Chizuko,Kabuto, Kuninobu
, p. 14 - 15 (2007/10/03)
The reactions of cis-Cp*W(CO)2(MeCN)Me (1) with thiophene or 3-methylthiophene resulted in selective α-C-H bond activation to give cis-Cp*W(CO)2(MeCN)R [R = 2-C4H3S (2a), 2-C4H2S-4-Me (2b)]
Palladium catalyzed cross-methylation of bromoheterocycles with intramolecularly stabilized dimethyl indium reagents
Jaber, Nimer,Schumann, Herbert,Blum, Jochanan
, p. 565 - 567 (2007/10/03)
Although the intramolecularly stabilized [(3- dimethylamino)propyl]dimethylaluminum (1a) fails to undergo palladium-catalyzed cross-coupling with bromopyridines and with bromofuran derivatives, the analogous gallium and indium reagent lb and 1c smoothly c
Influence of the texture of chromia catalysts on their activity in synthesis of 2-methylthiophene
Ryashentseva,Brueva
, p. 1694 - 1697 (2007/10/03)
The texture of Cr2O3-K2O/Al 2O3 catalysts containing oxides of rare earth elements (REE) was studied. The catalysts are used for the synthesis of 2-methylthiophene by the reaction of H2S with n-pentane or piperilene. The heterocyclization of n-pentane is a consecutive reaction involving a step of dehydrogenation of initial hydrocarbon. At this step the texture of the catalyst affects the yield of 2-methylthiophene. The yield of 2-methylthiophene obtained from piperilene and H2S is independent of the catalyst texture.
