6640-27-3Relevant academic research and scientific papers
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.
Ceria-promoted Co@NC catalyst for biofuel upgrade: synergy between ceria and cobalt species
Wang, Bowei,Gao, Ruixiao,Zhang, Dan,Zeng, Yuyao,Zhang, Fangying,Yan, Xilong,Li, Yang,Chen, Ligong
supporting information, p. 8541 - 8553 (2021/04/12)
Ceria-promoted Co@NC (NC, N doped carbon) catalysts are prepared by pyrolysis of biomass materials. Characterization results indicate that ceria and Co species facilitate the distribution of each other due to the formation of a Ce-O-Co solid solution. The specific surface area of the catalyst increased from 378.77 to 537.7 m2g?1viathe introduction of ceria. The electron transfer from Co to Ce further enhanced their interaction, and Co species facilitate the formation of more defective oxygen vacancies on ceria, which are beneficial to the activities of catalytic hydrogenation and catalytic transfer hydrogenation (CTH), respectively. Thus, Co/Ce@NC (0.99% Co loading) pyrolyzed at 850 °C exhibits excellent performance in the hydrodeoxygenation (HDO) of vanillin with high metal utilization. Catalytic hydrogenation and CTH coexisted in the presence of H2and ethanol, and >99% yield of creosol can be obtained in each of them. The reaction processes are monitored. No intermediate is found in aqueous media, while ethoxymethyl-4-methoxy-2-phenol is detected in ethanol. Moreover, Co/Ce@NC presents outstanding stability and general applicability. This work provides new insights into the construction of M@NC (M, metal) catalysts and the HDO process of biofuel upgrade.
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.
Rate enhancements due to ultrasound in isoquinolinium dichromate and isoquinolinium chlorochromate catalyzed chlorination of aromatic compounds in presence of KHSO4/KCl
Rajanna,Rao, A. Sambashiva,Chakravarthi,Reddy, K. Rajendar
, p. 167 - 170 (2017/12/26)
Chlorination of aromatic compounds underwent magnificent rate accelerations in isoquinolinium dichromate and isoquinolinium chlorochromate catalyzed chlorination of aromatic hydrocarbons in the presence of KCl and KHSO4. Reaction times reduced highly significantly from 4-5 h in conventional protocol to 30-40 min under sonication, followed by high yields of monochloro derivatives as products with high regioselectivity.
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.
Synthesis of deuterated benzopyran derivatives as selective COX-2 inhibitors with improved pharmacokinetic properties
Zhang, Yanmei,Tortorella, Micky D.,Wang, Yican,Liu, Jianqi,Tu, Zhengchao,Liu, Xiaorong,Bai, Yang,Wen, Dingsheng,Lu, Xin,Lu, Yongzhi,Talley, John J.
, p. 1162 - 1166 (2014/12/10)
We designed a series of specifically deuterated benzopyran analogues as new COX-2 inhibitors with the aim of improving their pharmacokinetic properties. As expected, the deuterated compounds retained potency and selectivity for COX-2. The new molecules possess improved pharmacokinetic profiles in rats compared to their nondeuterated congeners. Most importantly, the new compounds showed pharmacodynamic efficacy in several murine models of inflammation and pain. The benzopyran derivatives were separated into their enantiomers, and the activity was found to reside with the S-isomers. To streamline the synthesis of the desired S-isomers, an organocatalytic asymmetric domino oxa-Michael/aldol condensation reaction was developed for their preparation.
Multisubstituted benzo[b]furans through a copper- and/or palladium-catalyzed assembly and functionalization process
Arcadi, Antonio,Blesi, Federico,Cacchi, Sandro,Fabrizi, Giancarlo,Goggiamani, Antonella,Marinelli, Fabio
, p. 1857 - 1871 (2013/04/10)
Full details as well as the study of the scope, limitations, and further elaboration of a straightforward approach to the synthesis of 2,5,7-trisubstituted benzo[b]furans from 2-bromo- and 2-chloro-6-iodo-4- substituted phenols through a consecutive copper- and/or palladium-catalyzed assembly and functionalization process is described. Functionalization at the C(7) position is carried out by Suzuki-Miyaura cross-coupling, alkynylation, alkenylation, and C-N bond forming reactions. A one-pot protocol for the synthesis of 2,5,7-trisubstituted benzo[b]furans is also reported.
Cu-Mn spinel oxide catalyzed regioselective halogenation of phenols and N-heteroarenes
Singh, Parvinder Pal,Thatikonda, Thanusha,Kumar, K. A. Aravinda,Sawant, Sanghapal D.,Singh, Baldev,Sharma, Amit Kumar,Sharma,Singh, Deepika,Vishwakarma, Ram A.
experimental part, p. 5823 - 5828 (2012/09/05)
A novel simple, mild chemo- and regioselective method has been developed for the halogenation of phenols using Cu-Mn spinel oxide as a catalyst and N-halosuccinimide as halogenating agent. In the presence of Cu-Mn spinel oxide B, both electron-withdrawing and electron-donating groups bearing phenols gave monohalogenated products in good to excellent yields with highest para-selectivity. The para-substituted phenol gave monohalogenated product with good yield and ortho-selectivity. N-Heteroarenes such as indoles and imidazoles also gave monohalogenated products with high selectivity. Unlike the copper-catalyzed halogenation, the present method works well with electron-withdrawing group bearing phenols and gives comparatively better yields and selectivity. The Cu-Mn spinel catalyst is robust and reused three times under optimized conditions without any loss in catalytic activity. Nonphenolics did not undergo this transformation.
2,5,7-Trisubstituted benzo[b]furans through a copper- and/or palladium-catalyzed assembly and functionalization process
Arcadi, Antonio,Blesi, Federico,Cacchi, Sandro,Fabrizi, Giancarlo,Goggiamani, Antonella
scheme or table, p. 5149 - 5152 (2011/10/12)
A straightforward approach to the synthesis of 2,5,7-trisubstituted benzo[b]furans from 2-bromo- and 2-chloro-6-iodo-4-substituted phenols through a consecutive copper- and/or palladium-catalyzed assembly and functionalization process is described. Functionalization at the C(7) position is carried out by Suzuki-Miyaura cross-coupling and C-N bond forming reactions.
Facile p-toluenesulfonic acid-promoted para-selective monobromination and chlorination of phenol and analogues
Bovonsombat, Pakorn,Ali, Rameez,Khan, Chiraphorn,Leykajarakul, Juthamard,Pla-On, Kawin,Aphimanchindakul, Suraj,Pungcharoenpong, Natchapon,Timsuea, Nisit,Arunrat, Anchalee,Punpongjareorn, Napat
experimental part, p. 6928 - 6935 (2010/10/01)
para-Regioselective bromination of phenol and analogues, promoted by p-toluenesulfonic acid, is achieved in high to excellent yields at room temperature with N-bromosuccinimide. Chlorination with N-chlorosuccinimide and catalysed by p-toluenesulfonic acid also gives para-chlorinated phenol analogues in good yields at room temperature. para-Bromination of phenol, promoted by p-toluenesulfonic acid, is achieved in excellent yields at room temperature with N-bromosuccinimide. p-Toluenesulfonic acid is also effective as a promoter of para-chlorination with N-chlorosuccinimide.
