488-23-3Relevant articles and documents
Rates and Mechanism of Proton Transfer from Transient Carbon Acids. The Acidites of Methylbenzene Cations
Schlesener, C. J.,Amatore, C.,Kochi, J. K.
, p. 7472 - 7482 (1984)
The fast rates of proton transfer from various methylbenzene cation radicals to a series of substitued pyridine bases are successfully measured in acetonitrile solutions.The technique utilizes the production of the cation radical as a transient intermediate during the electron-transfer oxidation of the methylbenzene with an iron(III) oxidant.Complete analysis of the complex kinetics affords reliable values of the deprotonation rate constants k2 which span a range from 3 x 102 to more than 2 x 107 M-1 s-1.The relative acidities of the cation radicals of hexamethylbenzene, pentamethylbenzene, durene, and prehnitene can be obtained from the Broensted correlation of the deprotonation rate constants with the pyridine base strengths and the standard oxidation potentials of the methylarenes.An estimate of the acidity constant for the hexamethylbenzene cation radical is based on several empirical extrapolations to that of the toluene cation radical previously evaluated by Nicholas and Arnold on thermochemical grounds.The kinetic acidities of the various methylarene cation radicals are also examined in the context of the Marcus equation, as applied to proton transfer.The mechanism of proton transfer from these labile carbon acids is discussed with regard to the electronic effects relevant to the methylarene oxidation potential and the pyridine base strength, the kinetic isotope effects with deuterated methyl groups, the salt effects in acetonitrile, and the steric effects of ortho substituents on pyridine.
A 1, 2, 3, 4 - four-toluol preparation method
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, (2018/06/14)
The invention relates to the field of organic synthesis, discloses a 1, 2, 3, 4 - four-toluol preparation method, comprising: step 1:1, 7 - dimethyl - 4, 10 - dioxa - tricyclic [5.2.1 . 0] becc - 8 - 8 en - 3, 5 - dione synthetic; step 2:4, 7 - dimethyl - isobenzofuran - 1, 3 - dione synthetic; step 3:1, 2 - double-(hydroxy methyl) - 3, 6 - dimethylphenyl synthetic; step 4:1, 2 - (bromomethyl)-- 3, 6 - dimethylphenyl synthetic; step 5: 1, 2, 3, 4 - four-toluol synthesis. The invention to maleic anhydride, 2, 5 - dimethyl furan as raw materials, high purity of the 1, 2, 3, 4 - tetramethyl-benzene, this method has no high-temperature high-pressure and other dangerous reaction conditions, is not of a special material, and will not synthetic 1, 2, 4, 5 - substances such as tetramethyl-benzene, the final product does not need to follow-up separation, is suitable for industrial production.
Reaction routes in catalytic reforming of poly(3-hydroxybutyrate) into renewable hydrocarbon oil
Kang, Shimin,Yu, Jian
, p. 30005 - 30013 (2015/05/13)
Poly(3-hydroxybutyrate) or PHB is an energy storage material of microbial organisms and can be reformed into hydrocarbon oils rich with aromatic compounds. This work investigated the main reaction routes from PHB to the key intermediates and final hydrocarbons. The main sequential reactions under catalysis of phosphoric acid at moderate temperatures (200-230 °C) consist of: (1) decomposition of PHB into crotonic acid, a major monomeric intermediate, (2) deoxygenation of crotonic acid, and (3) combination of the deoxygenated molecules. The oxygen in PHB is removed as CO2 and H2O in stage (2), involving decarboxylation and ketonization of crotonic acid. The main aromatic compounds are formed in stage (3) from propylene and 2,3-dimethyl-2-cyclopenten-1-one as two key intermediates, the former from decarboxylation and the latter from ketonization of crotonic acid. The reaction routes reveal that the formation of aromatics is affected to a great extent by the concentrations of phosphoric acid and water in the reaction, which can be used to control the composition of hydrocarbon oil.
One-pot production of hydrocarbon oil from poly(3-hydroxybutyrate)
Kang, Shimin,Yu, Jian
, p. 14320 - 14327 (2014/04/17)
Poly(3-hydroxybutyrate) (PHB) is an energy storage material of many microbial species, and has been found to be an effective feedstock for production of renewable hydrocarbon oils. A high oil yield (up to 38.2 wt%) was obtained in a phosphoric acid (H3PO4) solution at mild temperatures (165-240 °C). PHB and crotonic acid (C4H 6O2), a dominant thermal degradation product of PHB, were deoxygenated mainly via decarboxylation, generating similar liquid and gaseous products. Carbon dioxide and propylene were the major products in gas phase with little CO formation. The hydrocarbon oil (C4-C16) is a mixture of alkanes, alkenes, benzenes and naphthalenes. Aromatics (C10-C15) were the major hydrocarbons in a 100 wt% H3PO4 solution, while alkenes and alkanes (C4-C9) were favored in diluted solutions (50 wt% to 85 wt% H 3PO4). The concentration of H3PO4 was a key factor that affected the oil composition and yield. A highly efficient decarboxylation of crotonic acid at 220 °C for 3 hours resulted in 70.8 wt% of oxygen being removed as CO2 and 57.0 wt% of carbon being recovered as hydrocarbon oil. The H3PO4 solution can be repeatedly used for high yield oil production. This work shows that a type of new biological feedstock can be used to produce renewable hydrocarbon oil in an efficient one-pot reaction. This journal is the Partner Organisations 2014.
Accurate oxidation potentials of benzene and biphenyl derivatives via electron-transfer equilibria and transient kinetics
Merkel, Paul B.,Luo, Pu,Dinnocenzo, Joseph P.,Farid, Samir
experimental part, p. 5163 - 5173 (2009/12/06)
(Graph Presented) Nanosecond transient absorption methods were used to determine accurate oxidation potentials (Eox) in acetonitrile for benzene and a number of its alkyl-substituted derivatives. Eox values were obtained from a combination of equilibrium electron-transfer measurements and electron-transfer kinetics of radical cations produced from pairs of benzene and biphenyl derivatives, with one member of the pair acting as a reference. Using a redox-ladder approach, thermodynamic oxidation potentials were determined for 21 benzene and biphenyl derivatives. Of particular interest, Eox values of 2.48 ± 0.03 and 2.26 ± 0.02 V vs SCE were obtained for benzene and toluene, respectively. Because of a significant increase in solvent stabilization of the radical cations with decreasing alkyl substitution, the difference between ionization and oxidation potentials of benzene is ～0.5 eV larger than that of hexamethylbenzene. Oxidation potentials of the biphenyl derivatives show an excellent correlation with substituent σ+ values, which allows Eox predictions for other biphenyl derivatives. Significant dimer radical cation formation was observed in several cases and equilibrium constants for dimerization were determined. Methodologies are described for determining accurate electrontransfer equilibrium constants even when dimer radical cations are formed. Additional equilibrium measurements in trifluoroacetic acid, methylene chloride, and ethyl acetate demonstrated that solvation differences can substantially alter and even reverse relative Eox values.
Cyclization of N,N-diethylgeranylamine N-oxide in one-pot operation: preparation of cyclic terpenoid-aroma chemicals
Takabe, Kunihiko,Yamada, Takashi,Miyamoto, Takenori,Mase, Nobuyuki
scheme or table, p. 6016 - 6018 (2009/04/11)
Acid promoted cyclization of the geranylamine N-oxide (E)-4 followed by base-catalyzed intramolecular aldol condensation afforded 1-acetyl-4,4-dimethyl-1-cyclohexene (7) in one-pot operation. Reduction of 7, which possess strong fruity odor, followed by lipase-catalyzed kinetic resolution furnished the acetate (R)-26 (>49.9% yield, >99% ee) and the recovered alcohol (S)-25 (>49.9% yield, >99% ee, herbal odor).
A novel reduction of polycarboxylic acids into their corresponding alkanes using n-butylsilane or diethylsilane as the reducing agent
Nimmagadda, Rama D.,McRae, Christopher
, p. 3505 - 3508 (2007/10/03)
A convenient one-pot reaction has been developed for the reduction of polycarboxylic acids on aliphatic and aromatic systems to their corresponding alkanes. The reduction utilises either diethylsilane or n-butylsilane as the reducing agent in the presence of the Lewis acid catalyst tris(pentafluorophenyl)borane.
Process for the production of mesitylene and durene
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Page 9, (2010/02/08)
A process is described for the contemporaneous preparation of mesitylene and durene, characterized in that mesitylene and durene are obtained exclusively starting from pseudo-cumene without the use of any further chemical compound, operating in continuous, at a temperature ranging from 210 to 400°C, at a pressure ranging from 1 to 50 bar, with a weight space velocity ranging from 0.1 to 20 hours-1 and in the presence of a catalyst based on crystalline metal-silicates in acid form. After the recovery of mesitylene and durene from the reaction raw product, some of the remaining components of the raw product itself are recycled and fed to the reactor together with the pseudo-cumene.
Process for the production of mesitylene and durene
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Page 7, (2008/06/13)
A process is described for the contemporaneous preparation of mesitylene and durene, characterized in that mesitylene and durene are obtained exclusively starting from pseudo-cumene without the use of any further chemical compound, operating in continuous, at a temperature ranging from 210 to 400° C., at a pressure ranging from 1 to 50 bar, with a weight space velocity ranging from 0.1 to 20 hours?1 and in the presence of a catalyst based on crystalline metal-silicates in acid form. After the recovery of mesitylene and durene from the reaction raw product, some of the remaining components of the raw product itself are recycled and fed to the reactor together with the pseudo-cumene.
Unprecedented double C-C bond cleavage of a cyclopentadienyl ligand
Xi, Zhenfeng,Sato, Kimihiko,Gao, Ye,Lu, Jianming,Takahashi, Tamotsu
, p. 9568 - 9569 (2007/10/03)
Double C-C bond cleavage of a cyclopentadienyl ligand proceeded to titanacyclopentadienes when 2 equiv of nitriles were added and the resulting two-carbon unit and three-carbon unit were converted into a benzene derivative and a pyridine derivative, respectively, in one-pot. Copyright
