The IR Photochemistry of Organic Compounds. II. The IR Photochemistry of Ethers: The Decomposition Patterns

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Abstract
The infrared multiple-photon decomposition (IRMPD) of saturated open-chain ethers has been systematically investigated with the intention of establishing their decomposition patterns. The main products in the IRMPD of ethers (1a–f, 2) are H2CO, CO, H2, and lower hydrocarbons. Acetaldehyde is additionally formed in the IRMPD of 1b and 1d, while acetone is formed in the IRMPD of 1d. The observed results are explained on the basis of the decomposition of the highly vibrationally excited ethers produced in the IRMP excitation. The initial process is the homolytic cleavage of a C–O bond to yield the corresponding alkyl and alkoxyl radicals. The alkyl radicals are trapped by Br2. Sequential splitting and addition reactions of the radicals yield primary products with a high internal energy. The primary products also decompose sequentially into stable products, in part. The sequential processes compete with collisional deactivation. Therefore, the branching ratio depends on the internal energy of the radicals and the primary products.