Quantitative recovery of volatiles from fats and oils by combined high vacuum degassing and thin film molecular distillation

Abstract

AbstractAn apparatus is described which in one unit combines conventional high vacuum degassing on cold finger with falling film molecular distillation. The upper part of the cold finger is for the collection of the most volatile substances, while the lower part is for the condensing of substances which are molecular distilled from a wiped falling film. All the connections in the glass apparatus are made from Teflon or Viton‐O‐rings, and the turning of the rotor in the molecular distillation part is carried out by means of a magnetic coupling. In this way, the risk for contamination is reduced greatly. As all volatile substances after the treatment of the oil are on the same cold finger, the collection can be made by a high vacuum distillation into a small glass chilled with liquid nitrogen. In the bp range of 40–450 C, the apparatus gives recoveries of volatiles in or below the ppm range between 71–114% with coefficients of variance between 5–23%. The recoveries are found with internal standards added before treatment of the oil. Below 70 C, the recoveries drop to some extent. The volatiles are substances with different kinds of functional groups, e.g. hydrocarbons, aldehydes, ketones, acids, esters, lactones, and sulfur containing substances.