Ethoxylation

The ethoxylation is the addition of ethylene oxide (oxirane ) to compounds such as alcohols, phenols, amines or carboxylic acids.

Implementation

Ethoxylation, the raw material with a catalyst such as Potassium hydroxide, and treated with ethylene oxide. The mixture is heated under nitrogen pressure at about 5 bar at temperatures between 80 and 150 ° C.

There is obtained a mixture having a relatively wide degree of ethoxylation. By choice of suitable catalysts, for example alkaline earth metal salts, the distribution of chain lengths may, however, be concentrated by evaporation. One then obtains the so-called "narrow range ethoxylates".

Reaction Example

Ethoxylation of an alcohol:

Ethoxylation of amines in the addition of ethylene oxide to the nitrogen is generally not need to be catalyzed, as this is nucleophilic enough.

Application

The ethoxylates thus obtained are produced in large scale and used for various purposes, for example:

Ethoxylates of fatty alcohols, castor oil, sorbitans ( esterified with fatty acids ), alkyl phenols, fatty amines or fatty acids are used as nonionic surfactants and as raw materials for anionic surfactants. By ethoxylation of polypropylene glycol ( PPG) block copolymers ( Pluronics ) are obtained, which also are used as nonionic surfactants.

By base-catalyzed ethoxylation of ethanediol ( ethylene glycol ) or by ring-opening polymerization polymerization of ethylene oxide with water as the starting molecule is obtained Polyglyvole whose low molecular weight homologues (also etherified and / or esterified) are used as solvents. Higher homologs such as are used as a lubricant, for the manufacture of hydraulic fluids, or as a binder.