Redox catalyst plus promoter for oxidation of hydrocarbons

A process for oxidizing a liquid mixture of saturated hydrocarbons having an average number of carbon atoms per molecule of 25 to 50 and containing at least one of an oxidizing inhibitor and redox metal catalyst poison to an acid number of up to at least about 45 to 50 comprising blowing air at a rate of 3.5 to 4.0 liters per minute per liter of hydrocarbons through a liquid mass of said hydrocarbons containing at least one of an oxidation inhibitor and redox metal catalyst poison in the presence of 0.03 to 0.04 percent by weight of manganese provided by manganese carboxylate, based on weight of said liquid hydrocarbons;

• and
• an oxidation promoting amount of calcium provided by water-lime slurry, the weight ratio of manganese to calcium being about 1:1 to 1:2;
• the temperature of reaction being 160.degree. C. to 165.degree. C., the pressure being 150 to 250 psig and the reaction being carried out for about 2 hours or less, thereby providing an oxidized hydrocarbon mixture having an acid number of at least about 45 to 50.