Poly(amide-acetals) and poly(ester-acetals) from 9(10)-formylstearic acid as stationary phases for gas chromatography.

Abstract

AbstractDiesters from the reaction product of methyl 9(10)‐formylstearate with pentaerythritol were condensed with diols and diamines to produce the respective linear poly(ester‐acetals) and poly(amide‐acetals). Like those derived from methyl azelaaldehydate, these polymers have latent crosslinking sites at the acetal bond and, when crosslinked on an acidic diatomaceous support, form useful stationary phases bonded to the support surface for gas chromatography. Unlike that derived from methyl azelaaldehydate, the linear poly(amide‐acetal) from methyl 9(10)‐formylstearate is soluble in solvents, so that column packings are more easily prepared and advantage can be taken of the more polar nature of the poly(amide‐acetal). The stationary phases derived from the formylstearate have a continuous operating range from at least −60 C to 190–220 C with no detectable amount of phase bleed. Bleeding gradually increases, but the packings are still useful in dual column, compensated systems to 290 C. The poly(amide‐acetal) derived from formylstearate has intermediate polarity, whereas the poly(ester‐acetal) counterpart is relatively nonpolar. Polarity of the poly(ester‐acetal) was greatly increased, whereas that of the poly(amide‐acetal) was slightly lowered by adding dimethyl 1,4‐cyclohexanedicarboxylate as a comonomer. Compounds of widely different polarities were separated with good resolution and adequate efficiency on these packings during programed or isothermal gas chromatography.