 Phosgene was synthesized by the Cornish chemist John Davy (1790–1868) in 1812 by exposing a mixture of carbon monoxide and chlorine to sunlight.He named it "phosgene" in reference of the use of light to promote the reaction; from Greek, "phos" (light) and "gene" (born).It gradually became important in the chemical industry as the 19th century progressed, particularly in dye manufacturing.