2049-95-8Relevant articles and documents
Nickel-catalyzed reductive deoxygenation of diverse C-O bond-bearing functional groups
Cook, Adam,MacLean, Haydn,St. Onge, Piers,Newman, Stephen G.
, p. 13337 - 13347 (2021/11/20)
We report a catalytic method for the direct deoxygenation of various C-O bond-containing functional groups. Using a Ni(II) pre-catalyst and silane reducing agent, alcohols, epoxides, and ethers are reduced to the corresponding alkane. Unsaturated species including aldehydes and ketones are also deoxygenated via initial formation of an intermediate silylated alcohol. The reaction is chemoselective for C(sp3)-O bonds, leaving amines, anilines, aryl ethers, alkenes, and nitrogen-containing heterocycles untouched. Applications toward catalytic deuteration, benzyl ether deprotection, and the valorization of biomass-derived feedstocks demonstrate some of the practical aspects of this methodology.
Synthesis method of tert-amylbenzene with controllable isomer content
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Paragraph 0029-0037, (2020/06/17)
The invention provides a synthesis method of tert-amylbenzene with controllable isomer content. The synthesis method comprises the following steps: 1) carrying out a substitution reaction on tert-amylalcohol and haloid acid to obtain a halopentane intermediate; 2) carrying out a Friedel-Crafts alkylation reaction on the halopentane intermediate and benzene under the catalysis of a Lewis acid to obtain tert-amylbenzene; wherein the Lewis acid is one of ZnCl2 and FeCl3 or a mixture of the ZnCl2 and the FeCl3; the temperature of the Friedel-Crafts alkylation reaction is -10 to 40 DEG C; the vacuum degree is absolute pressure of 2-75kPa; and the reaction time is 0.5-4 h. According to the synthesis method, by setting reasonable reaction steps, controlling reaction conditions, selecting a proper catalyst and the like, the isomerization ratio is reduced, and the tert-amyl product with high yield and high selectivity is obtained.
Tert-amylbenzene production technology
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Paragraph 0015, (2019/05/08)
The invention relates to the technical field of organic compound synthesis, in particular to a tert-amylbenzene production technology. The technology comprises following steps: (1), pure benzene is added to a 1000 L enamel reaction kettle, stirring is started, a compound catalyst is added, freezing is started, and the temperature in the reaction kettle is enabled to be reduced to 0 DEG C; (2), when the temperature is reduced to 0 DEG C, tert-amyl alcohol is dropwise added, the temperature is controlled at 0-5 DEG C in a dropwise adding process, and after tert-amyl alcohol is dropwise added, the temperature is continuously controlled at 0-5 DEG C and heat insulation is performed for 6 h; (3), water is added after heat insulation, a mixed solution is stirred for 5 min and left to stand for 1h, lower waste water is removed, an oil layer is pumped to another distillation still for distillation, pure benzene is removed by normal-pressure evaporation, then reduced-pressure distillation is performed, and a product with tert-amylbenzene content of 99% or higher is obtained. With the adoption of the technology, the catalyst is changed in tert-amylbenzene production, and the compound catalyst is adopted and is prepared from aluminum trichloride and ferric trichloride by compounding; isomers are not produced, and content of tert-amylbenzene in the product reaches 99% or higher.
MANUFACTURING METHOD OF ALKYL SUBSTITUTED AROMATIC HYDROCARBON
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Paragraph 0053-0055, (2019/01/22)
PROBLEM TO BE SOLVED: To provide a manufacturing method capable of enhancing conversion ratio of aromatic hydrocarbon of a reaction substance and manufacturing alkyl substituted aromatic hydrocarbon at high selectivity and high yield. SOLUTION: There is provided a manufacturing method of alkyl substituted aromatic hydrocarbon (X-2) including a process for alkylating an alkyl group in aromatic hydrocarbon having the alkyl group having a hydrogen atom at an α position (X-1) with alkene, in which a solid base (D) derived from a composition containing an alkali earth metal compound (A) containing one or more kind of magnesium oxide, magnesium hydroxide, magnesium carbonate, calcium oxide, calcium hydroxide, and calcium carbonate, a potassium compound (B) containing one or more kind of potassium hydroxide, and potassium carbonate, and a metal sodium (C) is used as a reaction catalyst for alkylation. SELECTED DRAWING: None COPYRIGHT: (C)2019,JPOandINPIT
Acylation mechanisms of DMSO/[D6]DMSO with Di-tert-butylketene and its congeners
Knorr, Rudolf
scheme or table, p. 6335 - 6342 (2011/12/05)
Dimethyl sulfoxide (DMSO) and tBu2C=C=O in diglyme require heating to about 150 °C to furnish the Pummerer-type product tBu 2CHCO2CH2SCH3 through a novel mechanistic variant. The "ester enolate" tBu2C=C(O -)-O-S+(CH3)2 arising through the reversible addition of DMSO (step 1) to C-1 of tBu2C=C=O must be trapped through protonation (step 2) at C-2 by a carboxylic acid catalyst to form tBu2CH-C(=O)-O-S+(CH3)2 so that the reaction can proceed. The ensuing cleavage (step 3) of the O-S bond and one of the C-H bonds in the-S(CH3)2 group (E2 elimination, no ylide intermediate) results in the formation of tBu2CHCO 2- and H3CS-CH2+, whose combination (step 4) generates the final product. With a mixture of DMSO and [D6]DMSO competing for tBu2C=C=O in diglyme, the small value of the kinetic H/D isotope effect (KIE) kH/kD = 1.26 at 150 °C indicates that the cleavage of the C-H/C-D bonds (step 3) does not occur in the transition state with the highest free enthalpy. Therefore, the practically isotope-independent steps 1 and 2 determine the overall rate. The alternative slow initial protonation at C-2 of tBu2C=C=O generating the acylium cation tBu2CHC≡O+ can be excluded. Preparatory studies were undertaken to compare the mechanistic behavior of tBu2C=C=O with that of two related acylating agents: (i) The anhydride (tBu2CHCO)2O affords the same Pummerer-type product more slowly, again with an unexpectedly small KIE of 1.24 at 150 °C, which indicates that the overall rate is limited here by the almost isotope-independent initial O-acylation of DMSO in the addition/elimination (AE) mechanism. (ii) The acyl chloride tBu2CHCOCl affords ClCH 2SCH3 through a more common mechanistic variant involving neither the ketene nor the acylium cation tBu2CHC≡O +: The modestly enhanced kH/kD value of 2.4 at 55 °C shows that the C-H/C-D bond fissions contribute to the overall rate in cooperation with the retarded initial O-acylation. Deuterium labeling was quantified through 1H and 13C NMR integrations of deuterium-shifted signals.
The positional and structural izomerization equilibrium of branched pentylbenzenes
Naumkin,Nesterova,Nesterov,Vodenkova,Golovin
experimental part, p. 141 - 148 (2011/08/05)
The equilibrium of the positional and structural isomerization of branched monopentylbenzenes, pentyltoluenes, and pentyl-o-xylenes was studied. It was found that the 1,2-dimethylpropyl substituted derivatives prevail over the 1,1-dimethylpropyl substituted isomers in the equilibrium mixture of all of the examined groups of compounds. The thermodynamic characteristics of the structural isomerization of pentylbenzenes were calculated from the experimental data.
Efficient synthesis of amylbenzenes over zeolite catalysts
Zhang, Huanyan,Liu, Yueming,Wu, Haihong,Jiang, Yongwen,He, Mingyuan,Wu, Peng
, p. 138 - 139 (2007/10/03)
The liquid-phase heterogeneous alkylation of benzene with 2-methyl-2-butene takes place actively and selectively over large-pore zeolite catalysts, which implies an environmentally friendly route for the synthesis of fert-amylbenzene. Copyright
Use of Catalytic Systems Based on Aluminum Chloride in Alkylation of Benzene
Polubentseva,Duganova,Mikhailenko
, p. 607 - 613 (2007/10/03)
Catalytic action of supported catalysts AlCl3-MeX/SiO2, where MeX is a salt of a metal with variable valence, in alkylation of benzene with isoamyl bromide is studied for various temperatures and contact times. Binary catalytic systems are more active (with respect to the yield of amylbenzenes) than straight SiO2-supported catalysts. To a certain extent, the catalytic activity of binary systems is due to the presence of modifiers: water of crystallization and alkyl halides. The support influences the activity and selectivity of the catalysts owing to interaction between the components. Supported catalysts AlCl3-MeX/SiO2 surpass AlCl3 in selectivity and the yield of target products and suppress side processes that accompany alkylation. A mechanism is proposed for alkylation of benzene with isoamyl bromide on the catalysts prepared.
ALKYLATION NON CONVENTIONNELLE DE FRIEDEL ET CRAFTS DES AROMATIQUES PAR LES ISO ET CYCLOALCANES INDUITE PAR LES CHLORURES-SELECTIVITE ET OPTIMISATION
Iraqi, A.,Gallo, R.,Phan Tan Luu, R.
, p. 548 - 554 (2007/10/02)
Friedel-Crafts alkylation of benzene by C5-C8 isoalkanes induced by tert-butyl chloride affords good yields in the presence of small amounts of AlCl3.The isomeric alkylbenzenes prepared by hydride transfer are similar to those obtained by direct alkylation from the corresponding equivalent alcohols and chlorides.The kinetic tertiary alkyl benzene rearranges to a more stable secondary isomer ; the formation of isomers discussed.Fragmentation of isoalkanes (when any) is very small except with isooctane which gives only a tert-butyl-cation.The reaction may be extended to toluene, chlorobenzene and dichlorobenzene with no major change in selectivity i.e. trans vs direct alkylation.An optimization of the reaction using dichlorobenzene increases significantly conversion and selectivity in trans-alkylation product and stresses the importance of low temperature (ca. 40 deg C) and small amounts of catalyst.
