Gas chromatographic determination of vapour pressures of pheromone-like compounds III. Aldehydes

Abstract

Equilibrium vapour pressures of six saturated and seventy-four mono-unsaturated C 10-C 16 even-carbon aldehydes were determined using a method based on gas chromatographic (GC) retention data. GC measurements were carried out on a 3-m HP-1 capillary column at five to seven temperatures in the range of 35–140 °C by utilising saturated n- 12, n- 13, n- 17 and n- 18 hydrocarbons as vapour pressure reference standards. A close correlation, viz. In P [Pa] = 14.008 - 1.105 n c ( r = 0.99%) has been found between the vapour pressures P and the number of carbon atoms ( n c), indicating a vapour pressure decrease by a factor of 3.02 for each CH 2 group added in the alkanal chain. For structurally similar subseries of alkenals ( ω−3, ω−5 and ω−7 unsaturation), the vapour pressures were also shown to have a simple dependence on n c. Within each alkenal subseries, isomers having Z-configuration had mostly greater vapour pressures than their E-counterparts.