Mengqi Bian,Rui Liu,Qinghai Zhang,Yunlong Qu,Guanghui Chen,Jihai Duan,Hui Zhao,Weiwen Wang
The one-step preparation of methacrylic acid from isobutylene presents a significant challenge. In this study, three-dimensionally ordered macroporous (3DOM) Mo-V-P-Ce was synthesized using the hard template method and employed as a carrier for heteropolyacids in the selective oxidation of isobutene (IBN) to produce methacrylic acid (MAA). The CuNH 4 PAV@3DOM Mo-V-P-Ce catalyst developed through this method exhibits an ordered macroporous structure, which significantly enhances its thermal stability. Additionally, it contains a significant number of active species (VO 2 + ) and appropriate moderately strong acidic centers, which collectively improve the overall performance of the catalyst. The combination of CuNH 4 PAV with the 3DOM structure increases the surface concentration of oxygen vacancy species, thereby promoting the catalytic activity of the composite catalyst in converting these oxygen vacancy species into lattice oxygen species. Notably, the selectivity of the synthesized heteropolyacid catalysts for MAA increased to 84 % after loading. This work offers a novel approach to the development of efficient catalysts.
The direct synthesis of methyl methacrylate from isobutene is of great importance in the chemical industry. The direct oxidation of isobutylene to methacrylic acid is one of the key steps, but the selectivity of methacrylic acid is low in the products of one-step oxidation of isobutylene. The efficient one-step oxidation of isobutylene to methacrylic acid was achieved by preparing a Mo-V-P-Ce/KCsWPAV two-component composite catalyst combining asymmetric lattice oxygen with appropriate acidic heteropolyacid catalysts. The catalyst was characterized using XRD, FT-IR, BET, SEM, and others to analyze its structural properties, dimensional characteristics, and more. Results indicated that the composite catalyst accelerated the crystallization rate, with Ce enhancing the oxidation of the active molybdenum species and promoting oxygen activation to form lattice oxygen, thereby improving the oxidation of isobutylene. The heteropoly acids increased the percentage of medium strong acidic sites, enhancing the selectivity of methacrylic acid. Under optimized conditions, with an atmosphere to isobutylene molar feed ratio of ≥25:1 and a temperature of 400 °C, the Mo-V-P-Ce/KCsWPAV catalyst achieved a remarkable 91 % conversion of isobutylene with a 70 % selectivity towards methacrylic acid. The catalyst shows promise for practical applications in the one-step oxidation of isobutylene to produce methacrylic acid, providing a suitable solution to the problem of isobutylene overcapacity.
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