The photochemistry of 2-furaldehyde vapour. II. Photodecomposition: direct photolysis at 253.7 and 313 nm and Hg( 3 P 1 )-sensitized decomposition

Abstract

The photolysis of furaldehyde vapour at 253.7 nm, 65 °C, and pressures from about 0.2 to 7 torr, produces CO, propyne, allene, furan, cyclopropene, CO 2 , and C 2 H 2 . The quantum yield of CO approaches 2 at low pressure and decreases towards zero with increasing pressure of furaldehyde or added CO 2 . Yields of the other products also decrease but show a more complex pressure dependence. A mechanism involving excited furaldehyde and excited C 4 H 4 O and C 3 H 4 intermediates is suggested.The Hg( 3 P 1 )-photosensitized decomposition gives products very similar to those of the direct photolysis. Photolysis at 313 and 366 nm also leads to similar products but in much lower yields, with the major product, CO, having a quantum yield of about 0.01. Some photopolymerization was observed in all Systems.