- Method for separating components in mixture containing methylbenzene, 2-methylthiophene and 3-methylthiophene
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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.
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Paragraph 0052; 0056; 0057; 0058
(2019/12/09)
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- Catalytic Synthesis of Methylthiophenes
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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%.
- Mashkina,Khairulina
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p. 1794 - 1797
(2019/03/26)
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- Hydrodecarboxylation of Carboxylic and Malonic Acid Derivatives via Organic Photoredox Catalysis: Substrate Scope and Mechanistic Insight
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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.
- Griffin, Jeremy D.,Zeller, Mary A.,Nicewicz, David A.
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supporting information
p. 11340 - 11348
(2015/09/21)
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- Preparation of an Arenylmethylzinc Reagent with Functional Groups by Chemoselective Cross-Coupling Reaction of Bis(iodoazincio)methane with Iodoarenes
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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.
- Shimada, Yukako,Haraguchi, Ryosuke,Matsubara, Seijiro
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p. 2395 - 2398
(2015/10/19)
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- User-friendly methylation of aryl and vinyl halides and pseudohalides with DABAL-Me3
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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.
- Cooper, Thea,Novak, Andrew,Humphreys, Luke D.,Walker, Matthew D.,Woodward, Simon
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p. 686 - 690
(2007/10/03)
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- Catalytic transformations of alkylthiophenes
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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
- Mashkina,Chernov
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p. 209 - 215
(2007/10/03)
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- Synthesis of tungsten thienyl complexes via C-H bond activation of thiophenes
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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)]
- Sakaba, Hiroyuki,Yumoto, Takahiro,Watanabe, Sanae,Kabuto, Chizuko,Kabuto, Kuninobu
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- Palladium catalyzed cross-methylation of bromoheterocycles with intramolecularly stabilized dimethyl indium reagents
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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
- Jaber, Nimer,Schumann, Herbert,Blum, Jochanan
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p. 565 - 567
(2007/10/03)
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- Gas-phase pyrolysis of thiopheneacetic acids, thienylethanols, and related compounds - Protophilicity of ring π-electrons and relative acidities of hydrogen-bond donors of hydroxyl groups
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Based on kinetic data of thermal gas-phase elimination reactions, the following Arrhenius log A (s-1) and Ea (kJ mol-1) values, respectively, are obtained: 10.76 and 153.5 for 3-thiopheneacetic acid (1), 10.08 and 149.4 for 2-thiopheneacetic acid (2), 12.04 and 207.1 for 2-(3-thienyl)ethanol (3), 11.55 and 203.3 for 2-(2-thienyl)ethanol (4), 10.91 and 123.4 for 2-thiopheneglyoxylic acid (5), 11.05 and 223.8 for 1-(2-thienyl)propan-1-one (6), and 10.33 and 149.8 for 3-thiophenemalonic acid (7). The products of these pyrolytic reactions were either carbon dioxide or formaldehyde in addition to methylthiophene or thiophenecarboxaldehyde. Both positional and molecular reactivities of the substrates and related compounds are compared, and the results are rationalized on the basis of a reaction pathway involving a concerted six-membered transition state.
- Al-Juwaiser, Ibtehal A.,Al-Awadi, Nouria A.,El-Dusouqui, Osman M.E.
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p. 499 - 503
(2007/10/03)
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- Influence of the texture of chromia catalysts on their activity in synthesis of 2-methylthiophene
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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.
- Ryashentseva,Brueva
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p. 1694 - 1697
(2007/10/03)
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- Thiophene synthesis
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A method of preparing a thiophene comprises reacting an organic compound containing a chain of at least 4 C atoms linked by single or double bonds with a source of sulphur in the vapour phase, in the presence of a jarosite-type catalyst, having the composition wherein M is NH4 or an alkali metal; and Xn represents one or more suitable anions.
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- Direct Carbonylation of Benzyl Alcohol and Its Analogs Catalyzed by Palladium and HI in Aqueous Systems and Mechanistic Studies
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Carbonylation of benzyl alcohol, benzyl formate, dibenzyl ether, and benzyl phenylacetate catalyzed by palladium complexes and promoted by hydrogen iodide gives phenylacetic acid in moderate to excellent yields in aqueous systems. Application of the carbonylation process to other arylmethanol analogs provides convenient means to prepare 2-naphthaleneacetic acid, 3-isochromanone, 1,4-benzenediacetic acid, and o-hydroxybenzeneacetic acid. A mechanism for the catalytic reaction is proposed, which involves (1) formation of benzyl iodide by the reaction of benzyl alcohol with HI in situ, (2) oxidative addition of benzyl iodide to palladium(0) to form a benzylpalladium iodide species. (3) CO insertion into the Pd-benzyl bond to form a (phenylacetyl)palladium iodide species. (4) reductive elimination of phenylacetyl iodide, and (5) its hydrolysis into phenylacetic acid. Evidence supporting the mechanism was obtained by examining the properties of benzyl- and (phenylacetyl)palladium iodide and chloride complexes. Formation of benzyl(carbonyl)palladium species and migratory insertion of the benzyl group to CO was confirmed by means of NMR at low temperature under high pressure.
- Lin, Yong-Shou,Yamamoto, Akio
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p. 723 - 734
(2007/10/03)
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- Palladium-catalyzed carbonylation of benzyl alcohol and its analogs promoted by HI in aqueous systems
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Carbonylation of benzyl alcohol catalyzed by a palladium(0) complex and promoted by hydrogen iodide gives phenylacetic acid in excellent yields in aqueous systems. The catalysis is proposed to proceed through a benzylpalladium species formed by the oxidative addition of benzyl iodide, produced in situ by the interaction of benzyl alcohol with HI, to a Pd(0) species. Application of the carbonylation process to other arylmethanol analogs provided convenient means to prepare 3-isochromanone, 1,4-benzenediacetic acid, 2-hydroxybenzeneacetic acid and 2-naphthaleneacetic acid.
- Lin, Yong-Shou,Yamamoto, Akio
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p. 3747 - 3750
(2007/10/03)
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- Competitive reactivities of vinylthiyl radicals thermally generated from haloethylenes and hydrogen sulfide
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Acetylene and its derivatives have been used for the first time as "traps" for vinylthiyl radicals generated in situ from hydrogen sulfide and haloethylenes in gas-phase processes. The competitive reactivity of the vinylthiyl radicals has been studied at 500-570 °C in the presence of two chemical "traps." The efficiency of chemical "traps" for the vinylthiyl radicals decreases in the following sequence: HC≡CPh > HC≡CH > MeC≡CH > CH2=CHCl. Acetylene is a more efficient "trap" for the vinylthiyl radicals than 1,2-dichloroethylene, from which they have been generated. The β-phenylvinylthiyl radicals generated during cothermolysis of halostyrene-hydrogen sulfide-acetylene component ternary systems undergo first of all intramolecular ring closure to give benzothiophene, which is a thermodynamically favorable system; the reaction of these radicals with acetylene and its derivatives occurs much more slowly than heterocyclization. Phenylacetylene is a more efficient "trap" than acetylene. α-Phenylvinylthiyl radicals mostly react with acetylene to yield 2-phenylthiophene.
- Deryagina,Sukhomazova,Levanova
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p. 662 - 666
(2007/10/03)
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- A Study of 2-Propenethials Obtained by Flash Vacuum Pyrolysis of 2-Ethenyl-1,3-dithiolane 1,1-Dioxides
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Synthesis of substituted 2-propenethials by the flash vacuum pyrolysis of appropriately substituted 2-ethenyl-1,3-dithiolane 1,1-dioxides has been investigated.Pyrolysis of 2-propenyl-1,3-dithiolane 1,1-dioxide (5a) gives thiophene, 2,5-dihydrothiophene, a dimer (11) and dimer (12) of 2-butenethial (4a).Pyrolysis of 2-(1-methylpropenyl)-1,3-dithiolane 1,1-dioxide (5b) gives 3-methylthiophene and a trimer (14) of 2-methyl-2-butenethial (4b).Pyrolysis of 2-(2-phenylethenyl)-1,3-dithiolane 1,1-dioxide (5c) gives 2H-1-benzothiin (15) and a dimer (16) of 3-phenyl-2-propenethial (4c).The dimer (11), 2-propenyl-4-methyl-4H-1,3-dithiin, can be considered as the meta-substituted cycloaddition product of 2-butenethial, whereas the dimer (16), 3-(2-phenylethenyl)-4-phenyl-3,4-dihydro-1,2-dithiin, can be considered as the ortho-substituted cycloaddition product of 2-phenyl-2-propenethial.
- Liao, Li-Fan,Tseng, Pen-Wen,Chou, Chin-Hsing,Chou, Wen-Chih,Fang, Jim-Min
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p. 1967 - 1978
(2007/10/02)
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- HIGH-TEMPERATURE ORGANIC SYNTHESIS XXXV. THERMAL REACTIONS OF DI(1-PROPENYL) SULFIDE
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The thermolysis of dipropenyl sulfide in a flow-type system in an atmosphere of nitrogen at 450-540 deg C leads to propenethiol, thiophene, methylthiophenes, and 2-ethylthiophene.The formation of the thiophene derivatives results from intramolecular radical cyclization of the initial sulfide.Dimethyl selenide (5-10 mole percent) substantially accelerates the thermolysis of dipropenyl sulfide, and the yield of 2-ethylthiophene at 450-480 deg C is increased appreciably.The high-temperature reactions of di(1-propenyl) sulfide with 2-halogenothiophenes and acetylene confirm that the propenethiol and thiophene derivatives are formed in parallel during the thermolysis of dipropenyl sulfide.
- Ostroukhova, L. A.,Deryagina, E. N.,Korchevin, N. A.,Musorin, G. K.,Amosova, S. V.,Voronkov, M. G.
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p. 301 - 305
(2007/10/02)
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- HETEROCYCLIZING PROPERTIES OF FERRISILICATE IN THE REACTION OF n-PENTANE WITH HYDROGEN SULFIDE
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Unlike the iron-modified pentasil, the ferrisilicate has high heterocyclizing activity in the formation of 2-methylthiophene from hydrogen sulfide and n-pentane.During the reaction and the subsequent regenerations a considerable proportion of iron ions leaves the ferrisilicate lattice.The heterocyclizing activity is probably related to the formation of a highly dispersed Fe sulfide phase in the zeolite channels.
- Ryashentseva, M. A.,Belanova, E. P.,Minachev, Kh. M.,Kucherov, A. V.
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p. 1551 - 1555
(2007/10/02)
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- Equilibrium studies of thiophene exchange in (η-thiophene)Ru(η-C5H5)+: A model for thiophene adsorption on hydrodesulfurization catalysts
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Equilibrium constants (K′) for the displacement of the π- (i.e., η5-) thiophene (T) ligand in CpRu(T)+ by methyl-substituted thiophenes (Th′), CpRu(T)+ + Th′ ? CpRu(Th′)+ + T, increase as the number of methyl groups in Th′ increases: T (1) 2T (35) 2T (50) 3T(200) 3T (300) 4T (1300). The K′ values increase by a factor of approximately 6 for each methyl in the thiophene (Th′). That thiophenes also adsorb to a Co-Mo/Al2O3 hydrodesulfurization (HDS) catalyst more strongly as the number of methyl groups in the thiophene increases suggests that they are also π-bonded to the catalyst surface. The results suggest that trends in rates of deuterium exchange and hydrodesulfurization on HDS catalysts for a series of methyl-substituted thiophenes are determined by their relative strengths of adsorption to the catalyst surface.
- Hachgenci,Angelici
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- Reactions of Thiophene and Alkylthiophenes in Glow Discharge
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The glow discharge reaction of thiophene is shown to produce thioketene and carbon monosulfide along with other gaseous products.The dominant liquid product is ethynylthiophene.Methylthiophenes and especially dimethylthiophenes produce benzene as one of the major liquid products.
- Skramstad, Jan,Chaudhry, Mohammed Shoaib,Garvang, Arne
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p. 509 - 512
(2007/10/02)
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- HIGH-TEMPERATURE ORGANIC SYNTHESIS. INVESTIGATION OF THE MECHANISM OF PYROLYSIS OF DIORGANIC SULFIDES BY THE CHLOROBENZENE TRAP METHOD
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The copyrolysis of various diorganic sulfides with chlorobenzene in the gas phase at 600-650 deg C was investigated.The degree of conversion of the chlorobenzene, which is a trap for thiyl radicals, increases with increase in the reaction temperature and depends significantly on the nature of the sulfide.The copyrolysis of chlorobenzene with branched dialkyl sulfides (secondary and tertiary) takes place more slowly than the reaction with the corresponding di(n-alkyl) sulfides.Alkyl vinyl sulfides are similar to the latter in reactivity.Ethyl β,β-dichlorovinyl sulfide and bis(ethylthio)acetylene have low reactivity.The main products from copyrolysis of all the diorganic sulfides with chlorobenzene are benzene, thiophenol, diphenyl sulfide, thiophene, and benzothiophene.The ratio between the products depends on the nature of the initial sulfide and an the temperature.The ratio between the thiophene and benzothiophene makes it possible to form an opinion about the mechanism of the formation of thiophene during the pyrolysis of the sulfides.Several paths were determined for the formation of the thiophene molecule through the thiyl radicals, and they supplemented the known mechanism of the pyrolysis of dialkyl sulfides, i.e., intermolecular cyclization of ethenethiol, intramolecular cyclization of butenethiol, cyclization of divinyl sulfide, and thermal dissociation of bis(ethylthio)acetylene.Intramolecular heterocyclization of the thiyl radicals is realized at a higher rate than intermolecular cyclization.
- Voronkov, M. G.,Deryagina, E. N.,Sukhomazova, E. N.,Mirskova, A. N.,Seredkina, S. G.
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p. 1453 - 1458
(2007/10/02)
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- Electrophilic Aromatic Substitution. Part 31. Partial Rate Factors for Detritiation of Thienothiophen and Thienothiophen: Weak Hydrogen Bonding to Sulphur in Trifluoroacetic Acid
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Thienothiophen (I) and thienothiophen (II), specifically labelled with tritium in each position have been prepared, and their rates of protiodetritiation measured along with that for thiophen in either pure trifluoroacetic acid, or mixtures of trifluoroacetic acid and acetic acid, all at 70 deg C.The dependence of exchange rate coefficients upon acid composition indicates that the ring sulphur is hydrogen bonded, and to an extent which depends upon the number of sulphur atoms in the heterocycle.Partial rate factors for detritiation of the non-hydrogen-bonded compounds are calculated as follows (position and compound in parentheses): 7.18E8 ; 6.83E8 ; 9.75E7 (2-thiophen); 7.59E5 ; 5.54E5 ; 7.84E4 (3-thiophen), the corresponding ?+-values being -1.012, -1.010, -0.913, -0.672, -0.656, and -0.560.The results, taken along with those for acylation and chlorination show that (II) is more polarisable than (I), so that these compounds, like all other ?-excessive heterocycles previously examined, are unsuitable for rigorous application of the Extended Selectivity Relationship.Annelation of thiophen by thiophen produces a comparable change in reactivities of the α- and β-positions in contrast to annelation by benzene, where the high resonance energy of benzene plays a crucial role in raising the reactivity of the β-position, relative to that of the α-position.
- Archer, William J.,Roger, Taylor
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p. 295 - 300
(2007/10/02)
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- Gas-Phase Heteroaromatic Substitution. 3. Electrophilic Methylation of Furan and Thiophene by CH3XCH3+ (X = F or Cl) Ions
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A previous radiolytic study on the gas-phase methylation of pyrrole and N-methylpyrrole by CH3XCH3+ (X = F or Cl) ions, from the γ radiolysis of CH3X, is extended to furan (3) and thiophene (4).The mechanism of the susbstitution and of the subsequent isomerization occuring via intramolecular 1,2 methyl-group shift is discussed and the substrate and positional selectivity of the selected electrophilic species evaluated.As for pyrroles, gas-phase CH3FCH3+ methylation of furan and thiophene is characterized by a scarce substrate discrimination (kS/kB = 1.2 (3), 0.8 (4), accompanied by an apprreciable positional selectivity toward those substrate positions with the highest negative net charge (O:α:β = 36percent:35percent:29percent for 3; S:α:β = 19percent:43percent:38percent for 4).On the contrary, CH3ClCH3+ confirm its inherent affinity toward n-type nucleophilic centers by attacking preferently the heteroatom of 3 and 4.In light of the previous results concerning CH3XCH3+ methylation of pyrroles, it is concluded that gas-phase attack of CH3XCH3+ on simple five-membered heteroaromatics is essentially regulated by the electrostatic interaction established within the encounter pair.A close correspondence does exist between this rationalization of the present gas-phase results and recent theoretical predictions.
- Angelini, Giancarlo,Lilla, Gaetano,Speranza, Maurizio
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p. 7091 - 7098
(2007/10/02)
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