GAS-CHROMATOGRAPHIC DETERMINATION OF VAPOR-PRESSURES OF PHEROMONE-LIKE COMPOUNDS .3. ALDEHYDES

Equilibrium vapour pressures of six saturated and seventy-four mono-un saturated C-10-C-16 even-carbon aldehydes were determined using a meth od based on gas chromatographic (GC) retention data. GC measurements w ere carried out on a 3-m HP-1 capillary column at five to seven temper atures in the range of 35-140 degrees C by utilising saturated n-C-12, n-C-13, n-C-17 and n-C-18 hydrocarbons as vapour pressure reference s tandards. A close correlation, viz. lnP [Pa] = 14.008 - 1.105n(c) (r = 0.9996) has been found between the vapour pressures P and the number of carbon atoms (n(c)), indicating a vapour pressure decrease by a fac tor of 3.02 for each CH2 group added in the alkanal chain. For structu rally similar subseries of alkenals (omega-3, omega-5 and omega-7 unsa turation), the vapour pressures were also shown to have a simple depen dence on n(c). Within each alkenal subseries, isomers having Z-configu ration had mostly greater vapour pressures than their E-counterparts.