Ethyl Corporation

Albemarle Corporation

Rebecca F Smith

Kim R Smith

Y-d Mark Chen

Joe D Sauer

James E Borland

R Woodrow Wilson, Jr

Sharon B McGee

Mayur P Shah

A highly pure, white, solid amine oxide is prepared in high yield with minimal decomposition of the solvent by (A) reacting a tert-amine with a 15-20% stoichiometric excess of concentrated hydrogen peroxide at 50.degree.-55.degree. C. in the presence of controlled amounts of carbon dioxide and ethyl acetate until the reaction mixture contains 35-45 % by weight of ethyl acetate and less than 0.8% by weight of unreacted amine, (B) catalytically decomposing residual hydrogen peroxide, (C) separating the reaction mixture from the decomposition catalyst, (D) cooling the reaction mixture to 0.degree. C. to form a slurry, (E) centrifuging the slurry to separate the amine oxide, and (F) vacuum drying the amine oxide at ambient temperature--the reaction mixture being diluted to an amine oxide content of 25-30% by weight with additional ethyl acetate or a mixture thereof with a co-solvent, such as a low-boiling n-alkane, after the completion of Step A and prior to the beginning of Step D.

Process for preparing solid amine oxides

A solid amine oxide is prepared by reacting a tert-amine with at least a stoichiometric amount of an aqueous hydrogen peroxide having a concentration of at least 50% by weight in the presence as the reaction medium of a normally gaseous material which (a) has a critical temperature &lt;160.degree. C. and a critical pressure &lt;12 MPa, (b) is in a liquefied, densified, or supercritical state in which it has a density of at least 0.1 g/cc, and (c) is present in an amount sufficient to maintain the reaction mixture stirrable throughout the reaction.

Amine oxides, such as amine oxide dihydrates, which have become discolored by being prepared from tert-amines and hydrogen peroxide in a liquid medium constituting not more than 50% of the weight of the reaction mixture and in the presence of carbon dioxide are bleached by exposing them to visible light, preferably incandescent light having a luminosity of at least about 1750 lumens.

Bleaching of colored amine oxides

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Baton Rouge, LA, United States of America

Rebecca F Smith