Separation of prepolymers of phenol-formaldehyde resins by supercritical-fluid chromatography

摘要: Abstract Prepolymers of random novolac and resol resins were separated according to the number nuclei (phenol groups) methylol groups attached nuclei. Temperature programming elution at a constant column pressure flow-rates both carbon dioxide modifier was applied in order decreasing temperature. Two pumps installed supercritical chromatography system deliver independently. Ethanol used as modifier. The initial temperature 120 or 150°C rate 3 4°C/min. back outlet UV detector between 154 178 kg/cm2. Nine oligomers for from dihydroxydiphenylmethanes (DPM) (dimer, dinuclear) decanuclear separated. percentages three isomers, 2,2′-, 2,4′- 4,4′-DPM, dinuclear 6, 26 68%, respectively. Seven isomers trinuclear assigned. Molecular weight averages calculated without any calibration standards, e.g., M w = 417 n 366 sample examined here. Mono- pentanuclear Peaks 2- 4-methylol phenols, 2,4- 2,6-dimethylol phenols 2,4,6-trimethylol phenol Di- groups.