ETHOXYLATION OF FATTY ALCOHOLS PROMOTED BY AN ALUMINUM ALKOXIDE SULFATE CATALYST

Aluminum alkoxides are moderately active in promoting the ethoxylation of fatty alcohols. When these alkoxides are treated with pure sulfuri c acid (100% by weight) in a stoichiometric ratio, the catalytic activ ity is strongly increased initially but it decreases rapidly giving pl ace to products being very interesting for industry as they contain no t more than two or three ethylene oxide adducts. These products are us eful as raw materials for producing surfactants by sulphonation. Alumi num in the catalyst used shows all the possible coordination numbers, as demonstrated with the aid of Al-27 NMR. The catalyst shows a very f eeble Bronsted activity. As a consequence, small amounts of polyglycol s are formed during reaction, in respect to the large amounts of ethox ylated dodecanol. Reaction rates are strongly inhibited by the presenc e of a Lewis base such as, for example, triphenylphosphine. The reacti on seems to occur in the coordination sphere of the aluminum atoms. Ot her factors influencing activity and selectivity have been examined an d a kinetic model has been developed on the basis of a reasonable reac tion mechanism.