ABSTRACT

Oligoalkylene glycols (OAGs) are produced by addition of epoxides (ethylene oxide, propylene oxide, butylene oxide) to a starting molecule. All the epoxides described can be converted to polymeric substances by opening the ring. Alkali is generally used as catalyst for this reason:

190-210 285-315 380-420 570-630

950-1,050 1,400-1,500 1,800-2,200 2,700-3,300 3, 700-4,500 5,600-7,000

8,500-12,500

170-220 450-800

or powder

Pale, hard waxy flakes or powder

0UGOETHERS 253

density (2)

Occasionally a request is made for a completely anhydrous PEG. This may well be an understandable wish where the product is to be processed with a number of water-sensitive substances. On the other hand, the very hygroscopicity of the liquid PEGs is an obstacle to absolute dehydration, and even the solid grades tenaciously retain a certain water content.