Baeyerl prepared this substance by the oxidation of cyclohexanol with Beckman's chromic acid mixture and proved its identity with the ketohexamethylene obtained by Perkin, Jr., from calcium pimelate. Baeyer used a proportion of 2 g. of cyclohexanol to 27 g. of the chromic acid mixture. The method used by us is essentiaily the same, modified slightly to keep the volumes down when dealing with roo-g. portions.
One hundred g. of cyclohexanol and 150cc. of water are placed in a one-liter flask and cooled in ice water. To this is added gradually 35 ce. of conc. sulfuric acid. One hundred g. of sodium dichromate (Na&rzOi- z&O) is dissolved in a solution of 35 cc. of conc. sulfuric acid in 150 ec. of mater. The chromic acid solution is added to th cyclohexanol mixture in IO cc. portions over a period of 2 hours, and the solution is shaken well after each addition. To complete the reaction the mixture is heated in a water-bath for z hours, cooled, and ether extracted, the extract dried with potassium carbonate and the ether distilled off. The cyclohexanone boils constantly ai. 155". Yield, 83 g. or 85%.
Hazards: concentrated sulfuric acid: hazardous in case of skin/eye contact, ingestion & inhalation; may produce burns with skin contact; non-flammable; may be combustible at high temps; reacts violently with