HYPERPRESSURE GAS CHROMATOGRAPHY .3. GAS CHROMATOGRAPHY OF PORPHYRINS AND METALLOPORPHYRINS

A number of porphyrins and metalloporphyrins have been separated by hyperpressure gas chromatography (HPGC), using dichlorodifluoromethane as the solvent gas and an epoxy resin (Epon 1001) as the selective liquid phase, at pressures up to 3100 psi and temperatures of 140-170°C. The separations effected were: Cu (or Mg), Ni, and vanadyl etioporphyrins II from each other; Sn etioporphyrin II, which is insoluble under the experimental conditions, is sharply separated from the above chelates; etioporphyrin II, mesoporphyrin IX diethyl ester, mesoporphyrin IX dimethyl ester, deuteroporphyrin IX dimethyl ester, and desoxophyllerythrin methyl ester from each other. Etioporphyrin II and desoxophyllerythroetioporphyrin were separated in a Versamid 900 column. Attempts to separate etioporphyrins II and III have failed but slightly different retention characteristics have been observed and the pyrolytically prepared etioporphyrin III could be resolved into the monomeric compound and the byproducts of the reaction. For porphyrins insoluble in CCl2F2, the addition of small amounts of a liquid solvent to the carrier gas is proposed. The above results indicate that hyperpressure gas chromatography is suitable (1) for nonvolatile compounds, which cannot be gas chromatographed by conventional methods, and (2) for the elution of compounds decomposed thermally at the temperatures suitable for their conventional gas chromatography. In conclusion, the first application of hyperpressure gas chromatography showed that the method is a powerful analytical tool for both inorganic and organic chemistry. © 1968.