Estimation of polyoxyethylene chain distribution of alcohol and alkylphenol ethoxylates

Oxyethylated nonylphenol and alcohols were analyzed by HPLC on normal phase s with mixtures of hexane, 2-propanol and water as mobile phases, using UV and evaporative light scattering (ELS) detectors. Effects of selected analy tical conditions (type of detector, drift tube temperature and gradient) on determined distributions are discussed. The distributions of oxyethylated alcohols obtained in the presence of NaOH and calcium-based W7(TM) catalyst and polyoxyethylene glycols present in products were compared. The distrib ution of oxyethylated alcohols and alkylphenols were fitted for normal dist ribution characterized by the mean and the standard deviation. It was found that the analytical results fitted the normal distribution quite well. The estimated mean agrees with the average degree of oxyethylation and the sta ndard deviation can be used as a measure of the distribution broadness.