Highly Efficient Supramolecular Catalysts Assembled by Dawson-Type POMs and Metal-Organic Complexes for the Synergistic Catalytic Synthesis of p-Benzoquinones was written by Chang, Shenzhen;An, Haiyan;Chen, Yanhong;Zhu, Qingshan;Luo, Huiyun;Huang, Yaohui. And the article was included in ACS Sustainable Chemistry & Engineering in 2022.Application In Synthesis of 2,3-Dimethoxy-5-methylcyclohexa-2,5-diene-1,4-dione This article mentions the following:
Selective oxidation of alkyl-substituted phenols offers an ideal pathway to synthesize p-benzoquinones (p-BQs), but it is known to be inefficient because of the parallel competing reactions. Aiming at the design and synthesis of more powerful heterogeneous catalysts for highly efficient synthesizing functionalized p-BQs, herein, authors report two crystalline catalysts with supramol. networks based on Dawson-type polyoxometalates (POMs) and metal-organic subunits, H4K(H2O)3[Cu3(H2O)8(ptz)4][Cu1.5(H2O)3(ptz)2(ina)][P2W18O62]2·ina·21H2O (1) and [Cu4.5(ptz)4(OH)3(H2O)4][P2W18O62]·10H2O (2), where ptz = 5-(4-pyridyl)-1H-tetrazole and ina = isonicotinic acid. Structural anal. shows that 1 is formed by the supramol. contact between one-dimensional POM inorganic chains and two kinds of trinuclear Cu-organic clusters, while 2 is formed by supramol. stacking of ladder-like one-dimensional chains that are composed of ribbonlike nonanuclear Cu-organic clusters and POM anions. Both supramol. catalysts exhibit high catalytic activity in H2O2-based oxidation of phenols/aromatics to p-BQs. Strikingly, in the synthesis of trimethyl-p-benzoquinone (TMBQ, an intermediate of vitamin E) by oxidizing 2,3,6-trimethylphenol, the conversion, selectivity, and oxidant efficiency can reach >99, 97.9, and 85.0% for 1, as well as 95.4, >99, and 79.8% for 2 within 5 min, resp. Also, the catalytic activities of 1 and 2 presented by the turnover frequency are 12 000 (the highest thus far) and 7632 h-1, resp. Detailed structure-activity anal. revealed that the higher performance of 1 is attributed to the more active-site accessibility due to the supramol. interactions between POM and Cu organic units in the framework. Moreover, the observed yield of TMBQ has not decreased and the skeleton of catalysts has not changed in >10 cycles. The reaction mechanism was also systematically studied, and the parallel dual center, namely, Cu-site and POM, -driven reaction processes (radical and oxygen transfer) were illuminated. In the experiment, the researchers used many compounds, for example, 2,3-Dimethoxy-5-methylcyclohexa-2,5-diene-1,4-dione (cas: 605-94-7Application In Synthesis of 2,3-Dimethoxy-5-methylcyclohexa-2,5-diene-1,4-dione).
2,3-Dimethoxy-5-methylcyclohexa-2,5-diene-1,4-dione (cas: 605-94-7) belongs to ethers. Ethers are good solvents partly because they are not very reactive. Most ethers can be cleaved, however, by hydrobromic acid (HBr) to give alkyl bromides or by hydroiodic acid (HI) to give alkyl iodides. The unique properties of ethers (i.e., that they are strongly polar, with nonbonding electron pairs but no hydroxyl group) enhance the formation and use of many reagents. For example, Grignard reagents cannot form unless an ether is present to share its lone pair of electrons with the magnesium atom. Complexation of the magnesium atom stabilizes the Grignard reagent and helps to keep it in solution.Application In Synthesis of 2,3-Dimethoxy-5-methylcyclohexa-2,5-diene-1,4-dione
Referemce:
Ether – Wikipedia,
Ether | (C2H5)2O – PubChem