Selective oxidation of toluene to benzaldehyde by O{sub 2} with visible light in barium(2+)- and calcium(2+)-exchanged zeolite Y
- Lawrence Berkeley Lab., CA (United States)
High selectivity has been demonstrted upon visible light induced oxygenation of toluene to benzaldehyde in alkaline earth exchanged zeolite Y. We attribute the tight product control to mainly two factors. One is access to the C{sub 6}H{sub 5}CH{sub 3}-O{sub 2} excited charge-transfer state by light of sufficiently long wavelength to prevent loss of product control by photofragmentation of primary products or by homolysis of the proposed hydroperoxide intermediate. The second is confinement of benzyl/HO{sub 2} radical pairs to the zeolite matrix cage, which suppresses indiscriminate attack of these radicals and forces them to combine. The Co{sup 3+}-catalyzed radical oxidation of toluene by O{sub 2} in solution used currently in an industrial process for benzaldehyde synthesis lacks this selectivity, mainly because of continued oxidation of the aldehyde to benzoic acid. 24 refs., 2 figs.
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 102770
- Journal Information:
- Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Journal Issue: 17 Vol. 116; ISSN JACSAT; ISSN 0002-7863
- Country of Publication:
- United States
- Language:
- English
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