Gas-chromatographic analysis of polyurethane polyethers by using a mixed anhydride reagent for the cleavage of ether linkages

Abstract

The polyethers formed from propylene glycol, glycerol, trimethylol-propane [1,1,1-tris(hydroxymethyl)propane], pentaerythritol, sorbitol, triethanolamine, 1,2-diaminoethane and 2,2′-diaminodiethylamine, and which are used in the manufacture of polyurethane foams, have been qualitatively analysed by gas chromatography after conversion of the base compounds into their corresponding acetates by using the mixed anhydride of acetic and toluene-p-sulphonic acids as a reagent for cleavage for the ether linkages. The polyethers are allowed to react with the reagent at 120 °C for 2 hours. The reaction products are extracted with diethyl ether and the concentrated extract is subjected to gas chromatography. As, under appropriate conditions, the peaks of these acetates appear at different positions, they were easily distinguished.

The proportions of oxyethylene and oxypropylene groups in the polyethers can also be determined by gas-chromatographic analysis of the acetylation products.