Chromatography of Rubber Accelerators and Anti-Oxidants on Silica Gel

Abstract

THE chromatographic separation on alumina columns of certain constituents from the acetone extracts of vulcanized rubbers has been reported by Bellamy and co-workers1 and by Mann2. As an adsorbent for such materials, alumina suffers from certain disadvantages, in particular, its tendency to favour chemical change in labile adsorbates. The successful use of silica gel/‘Celite’ for the chromatographic separation of a variety of ingredients from propellants and high explosives3,4 suggested that this adsorbent might prove equally useful for the separation of the ingredients of vulcanized rubbers, and this has, in fact, been borne out by recent work in this laboratory. The procedure adopted for the qualitative examination of a rubber extract is as follows. A number of separate portions of the extract (each equivalent to 0.2–0.4 gm. of the rubber) are chromatographed on 1-cm. diameter columns using a series of different binary solvent mixtures as developers. When the extruded columns have been streaked with appropriate reagents, the positions of the zones, together with the colours of the streaks, give a reasonably unambiguous identification, which can be further confirmed by ultra-violet absorption measurements.