6640-27-3Relevant articles and documents
Kinetics and process parameter studies in oxidative chlorination of 4-methylphenol under phase-transfer conditions
Mukhopadhyay, Sudip,Mukhopadhyaya, Jayanta K.,Ponde, Datta E.,Cohen, Shlomo,Kurkalli, Basan G. S.
, p. 509 - 512 (2000)
The effect of phase-transfer catalysts on the rate and selectivity of oxidative chlorination of 4-methylphenol was studied in ethylenedichloride with HCl-H2O2. Under identical reaction conditions, the rate of oxidative chlorination increased 6-7-fold in the presence of a phase-transfer catalyst (PTC) like tetraheptylammonium chloride in comparison to an ordinary two-phase system with no PTC. The activation energy was found to be 78 kJ/mol, and the reaction was found to be first-order on 4-methylphenol. An appropriate mechanism has been proposed.
Nickel-catalyzed intelligent reductive transformation of the aldehyde group using hydrogen
Tong, Xinli,Guo, Pengfei,Liao, Shengyun,Xue, Song,Zhang, Haigang
, p. 5828 - 5840 (2019/11/11)
The selective transformation of the aldehyde group (-CHO) in multifunctional oxygenates is a key challenge in the development of sustainable biomass feedstock. Herein, a smart Ni-MFC catalyst was developed from a 2D Ni-based metal-organic framework (MOF), which efficiently promoted the transformation of -CHO in the presence of H2 to a methyl group (-CH3) via the reductive etherification and hydrogenolysis of the C-O ether bond in methanol. Moreover, the catalytic process could be controlled to directionally produce methyl ether (-CH2OR) using the reductive etherification protocol. For the catalytic reduction of vanillin, the Ni-MFC-700 catalyst guaranteed the full conversion of vanillin and 96.5% yield of the desired 2-methoxy-4-methylphenol (MMP), while the Ni-MFC-500 catalyst afforded about 82.7% yield of 4-(methoxymethyl)-2-methoxyphenol in methanol solvent. This is a novel and promising approach for the valorization of multifunctional oxygenates and biomass-derived platform compounds.
Kinetic and Mechanisms of the Homogeneous, Unimolecular Elimination of Phenyl Chloroformate and p-Tolyl Chloroformate in the Gas Phase
Lezama, Jesus,Chuchani, Gabriel
, p. 664 - 670 (2015/09/07)
The gas-phase elimination of phenyl chloroformate gives chlorobenzene, 2-chlorophenol, CO2, and CO, whereasp-tolyl chloroformate produces p-chlorotoluene and 2-chloro-4-methylphenol CO2 and CO. The kinetic determination of phenyl chloroformate (440-480oC, 60-110 Torr) and p-tolyl chloroformate (430-480°C, 60-137 Torr) carried out in a deactivated static vessel, with the free radical inhibitor toluene always present, is homogeneous, unimolecular and follows a first-order rate law. The rate coefficient is expressed by the following Arrhenius equations: Phenyl chloroformate: Formation of chlorobenzene, log kI = (14.85 ± 0.38) - (260.4 ± 5.4) kJ mol-1 (2.303RT)-1; r = 0.9993 Formation of 2-chlorophenol, log kII = (12.76 ± 0.40) - (237.4 ± 5.6) kJ mol-1(2.303RT)-1; r = 0.9993 p-Tolyl chloroformate: Formation of p-chlorotoluene: log kI = (14.35 ± 0.28) - (252.0 ± 1.5) kJ mol-1 (2.303RT)-1; r = 0.9993 Formation of 2-chloro-4-methylphenol, log kII = (12.81 ± 0.16) - (222.2 ± 0.9) kJ mol-1(2.303RT)-1; r = 0.9995 The estimation of the kI values, which is the decarboxylation process in both substrates, suggests a mechanism involving an intramolecular nucleophilic displacement of the chlorine atom through a semipolar, concerted four-membered cyclic transition state structure; whereas the kII values, the decarbonylation in both substrates, imply an unusual migration of the chlorine atom to the aromatic ring through a semipolar, concerted five-membered cyclic transition state type of mechanism. The bond polarization of the C-Cl, in the sense Cδ+Clδ-, appears to be the rate-determining step of these elimination reactions.
