The simplest approach to prepare solutions of polyynes in hydrocarbons

Polyynes solutions having as main components C6H2 and C8H2 can be prepared in hydrocarbon solvents by hydrolyzing calcium carbide in an NH4Cl aqueous solution containing Cu(I)/Cu(II) salts. The polyynes are released into a hydrocarbon solvent by acidification with concd. HCl. Heptane solutions with polyynes concentration as high as 0.1 M can be easily prepared.