19956-76-4Relevant articles and documents
Synthesis of Alkyl Substituted p-Benzoquinones from the Corresponding Phenols Using Molecular Oxygen Catalyzed by Copper(II) Chloride-Amine Hydrochloride Systems
Shimizu, Masao,Watanabe, Yoshihito,Orita, Hideo,Hayakawa, Takashi,Takehira, Katsuomi
, p. 1522 - 1526 (1992)
2,4,6-Trimethylphenol was effectively oxidized to trimethyl-p-benzoquinone with molecular oxygen in the presense of a catalytic amount of copper(II) chloride-amines in alcohol at ambient temperature.Various amines could be used as a co-catalyst in the presence of acids, and especially hydroxylamine hydrochloride and acetone oxime coupled with hydrochloric acid showed high activity. 2,6-Dimethyl-p-benzoquinone was also obtained from 2,6-dimethylphenol in good yield in this catalytic oxidation system.
A Novel Synthesis of Trimethyl-p-benzoquinone: Copper(II)-hydroxylamine catalysed Oxygenation of 2,3,6-Trimethylphenol with Dioxygen
Takehira, Katsuomi,Shimizu, Masao,Watanabe, Yoshihito,Orita, Hideo,Hayakawa, Takashi
, p. 1705 - 1706 (1989)
2,3,6-Trimethylphenol was efficiently oxygenated to trimethyl-p-benzoquinone with molecular oxygen in the presence of a catalytic amount of copper(II) chloride-hydroxylamine in an alcoholic solvent at ambient temperature.
Large centimeter-sized macroporous ferritin gels as versatile nanoreactors
Kumari, Sushma,Kulkarni, Amol,Kumaraswamy, Guruswamy,Sen Gupta, Sayam
, p. 4813 - 4819 (2013)
Organized assemblies of bionanoparticles such as ferritin provides templates that can be exploited for nanotechnological applications. Organization of ferritin into well-defined three-dimensional assemblies is challenging and has attracted considerable attention recently. We have synthesized, for the first time, large (centimeter-sized) self-standing macroporous scaffold monoliths from ferritin bionanoparticles, using dynamic templating of surfactant H1 domains. These scaffolds comprise three-dimensionally connected strands of ferritin, organized as a porous gel with porosity ～55 μm. The iron oxide inside the ferritin scaffold can be easily replaced with catalytically active monodisperse zerovalent transition metal nanoparticles using a very simple protocol. Since the ferritin is cross-linked in the scaffold, it is significantly robust with enhanced thermal stability and better tolerance toward several organic solvents in comparison to the native ferritin bionanoparticle. In addition, the scaffold macropores facilitate substrate and reagent transport and hence the monoliths containing active Pd or iron oxide nanoparticles inside apo-ferritin bionanoparticles were used as a recyclable heterogeneous catalyst for the oxidation of 2,3,6-trimethyl phenol to 2,3,6-trimethyl-1,4-benzoquinone (precursor for Vitamin E synthesis) and for Suzuki-Miyaura cross-coupling reaction in both aqueous and organic solvents. The protein shell around the nanoparticles protects them from agglomeration, a phenomenon that otherwise plagues nanoparticles-based catalysis. The presence of macropores allow the ferritin scaffold to act as catalytic monolith for continuous flow reactions having rapid reaction rates, while offering a low pressure drop. Finally, the Pd@apo-ferritin scaffold was immobilized inside a steel cartridge and used for the continuous flow hydrogenation of alkenes to their corresponding alkanes for 15 cycles without any loss of activity.
The efficient catalytic oxidation of 2,3,6-trimethylphenol with air over composite catalyst to synthesize Vitamin E intermediate
Zhang, Tianyong,Song, Yuxin,Yang, Yang,Li, Bin,Jiang, Shuang
, p. 3705 - 3718 (2021)
2,3,5-Trimethylbenzoquinone (TMBQ)is a kind of crucial intermediate in the synthesis of Vitamin E, whose demand is increasing rapidly. The traditional synthesis method of TMBQ needs H2O2 or pure O2 as the oxidant, which is expensive and needs much attention in the production, transportation and storage process. In order to overcome the issues, the green oxidant, air, has been developed in this work to prepare TMBQ for the first time. TMBQ was synthesized from 2,3,6-trimethylphenol (TMP) with the oxidant of air in the solvent of isoamylol catalyzed by composite catalyst of inorganic salts at one atmosphere pressure. The critical reaction parameters, including the ingredient of composite catalyst, reaction time, reaction temperature, stirring speed and the addition of ionic liquids were investigated in order to achieve the optimal reaction condition. TMBQ was obtained with the conversion of 100% and selectivity of 96.7% at 90?°C for 7–8?h at one atmosphere pressure, over the composite catalyst, the aqueous solution of CuCl2, FeCl3 and MgCl2, with the help of ion liquid, 1-sulfobutyl-3-methylimidazole hydrochloride ([Bmim]Cl). Moreover, the catalyst could be recycled more than four times. Air is very cheap, abundant, eco-friendly and safe in production, transportation and storage process. The synthesis of TMBQ from TMP with air as oxidant at one atmosphere pressure has obvious advantages, which will bring new inspiration for the industrial production of TMBQ. Graphic abstract: [Figure not available: see fulltext.].
Effect of combination sequence of precursors on the structural and catalytic properties of Ti-SBA-15
Kuo, Feng-Ting,Chen, Shih-Yuan,Lin, Tsung-Han,Lee, Jyh-Fu,Cheng, Soofin
, p. 12604 - 12610 (2013)
The combination sequence of Ti and Si precursors (TTIP and TEOS) in the synthesis solution of Ti-incorporated SBA-15 mesoporous silica (shortly termed Ti-SBA-15) was found for the first time to be critical for the distribution of tetrahedrally (Td) coordinated Ti(iv) sites in the resultant Ti-SBA-15. It was found that TTIP pre-assembled with P123 in the synthesis solution for 3 h before the addition of TEOS gave Td-coordinated Ti(iv) sites predominately incorporated near the superficial regions of the framework and were highly accessible to the reactants in catalytic reactions. The Royal Society of Chemistry 2013.
A green catalytic method for selective synthesis of iodophenols via aerobic oxyiodination under organic solvent-free conditions
Xin, Hongchuan,Hu, Liangning,Yu, Jianqiang,Sun, Wenshou,An, Zengjian
, p. 1 - 4 (2017/01/28)
A highly efficient catalytic method for aerobic oxyiodination of various phenols catalysed by copper(II) nitrate was achieved under mild conditions using I2as an iodinating reagent, molecular oxygen as an oxidant, and water as a solvent. The catalyst shows not only high activity for phenols with either electron-donating or electron-withdrawing groups, but also a remarkable selectivity for the formation of para-iodo substituted phenols. This study offers a green method for iodination of aromatic phenols with high atom economy.
