HIGH-TEMPERATURE STABILITY OF ALCOHOL ETHOXYLATES

The oxidative stability of alcohol ethoxylates during storage and handling is studied. Realistic conditions are modelled by heating in quiescent air. More rigorous, extensively aerated conditions are modelled by thermogravimetry with mass spectrometric detection and differential scanning calorimetry with vapor-phase sampling. In quiescent air, C-12-15 alcohol with an average of 7 moles ethylene oxide (EO) is discolored at 204 degrees C, with some increase in aldehydes, but there is no change in the EO distribution of the sample. Under extensively aerated conditions, increased oxidation occurs above 150 degrees C, with a loss of one EO unit on average, and increases in CO and CO2 occur in the vapor phase above the sample. High-temperature oxidation under extensive aeration is not affected by an antioxidant or by raising the pH of the sample from 6.4 to 7.5.