It is a yellow-brown solid which is stable in air for long periods. If it has deteriorated or been kept for too long, it is best to prepare it freshly. Add freshly distilled quinoline (13mL) to a mixture of chromic acid (CrO3) (10g) and ~ 5M HCl (11mL of conc HCl and 10mL of H2O) at 0o. A yellow-brown solid separates, it is filtered off on a sintered glass funnel, dried for 1hour in a vacuum, and can be stored for extended periods without serious loss in activity. It is a good oxidant for primary alcohols in CH2Cl2. [Singh et al. Chem Ind (London) 751 1986, method of Corey & Suggs Tetrahedron Lett 2647 1975, Beilstein 20/7 V 276.]
