Mechanism of dimethyldichlorosilane preparation by NH2-MIL-53(Al)@γ-Al2O3 core-shell catalyst before and after AlCl3 modification

• Published in: Journal of solid state chemistry 2024-03, Vol.331, p.124529, Article 124529
• Main Authors: Xu, Wenyuan, Mo, Liubin, Cheng, Zhaohua, Si, Haoting, Shen, Mengsha, Fang, Zhili, Peng, Jiaxi, Liao, Mengyin, Chen, Xi
• Format: Article
• Language: English
• Subjects: Core-shell catalyst; Lewis acid; NH2-MIL-53(Al); Organosilicone; Theory; γ-Al2O3
• ISSN: 0022-4596
• DOI: 10.1016/j.jssc.2023.124529

The irreplaceable silicone materials among the high-tech industry is dimethyldichlorosilane, a monomer whose by-products generated in the synthesis step can be recycled through disproportionation reactions. In this paper, the catalytic activities of NH2-MIL-53(Al)@γ-Al2O3 with Brønsted acid active sites and AlCl3/NH2-MIL-53(Al)@γ-Al2O3 core-shell catalysts with Lewis acid active sites were investigated and compared for the disproportionation to prepare dimethyldichlorosilane by means of the M06-2X/Def2-TZVP hybrid functional method. The results given for structure, energy, vibrational frequency, IRC values, bond order, ELF and LOL analysis were matched. The results showed that AlCl3/NH2-MIL-53(Al)@γ-Al2O3 core-shell catalyst with Lewis acid was more active. Simulated synthesis and interatomic correlation parameters (bond length/nm and bong angle/o) of NH2-MIL-53(Al)@γ-Al2O3 (Cat. ,active site No.1-3) and AlCl3/NH2-MIL-53(Al)@γ-Al2O3 (Cat.&, Configuration a-d). [Display omitted] •Proposed four- and six-step disproportionation allows recycling of (CH3)3SiCl and CH3SiCl3.•Loading of AlCl3 presents Lewis catalytic centers, which possess enhanced catalytic activity compared to Brønsted acid.•Optimization of MOFs-based catalysts with core-shell structure, NH2-MIL-53(Al)@γ-Al2O3 and AlCl3/NH2-MIL-53(Al)@γ-Al2O3.