Amine oxides which have decreased levels of nitrosamines are made by reacting tert-amines with hydrogen peroxide in the presence of titanium metal. Addition of carbon dioxide to the process results in a substantially nitrosamine-free amine oxide.
Novel polymeric rhodium catalysts having repeating subunits of Formula (I), wherein R
1
-R
8
, X, A, m, n and p are as defined in the application, are described along with methods of using these catalysts, as well as precursors therefor, in the chemical synthesis transformations.
Tertiary amine oxides are made which are substantially free of nitrosamine impurities by reacting the desired tert-amine with aqueous hydrogen peroxide in the presence of carbon dioxide and at a temperature below about 45°C, especially below 40°C. Nitrosamines are suspect carcinogens and mutagens.
Reaction of amine-containing substrates with hydrogen peroxide can suffer from the problems of in situ generation of nitrosamines, which are allegedly carcinogens, as impurities and impaired product formation, especially in the presence of transition metals.
The problems can be ameliorated by employing a selected range of alkyleneaminopoly(methylenephosphonic acid) compounds such as cyclohexane-1,2-diaminotetra(methylenephosphonic acid).