Diketene are chemicals, molecular weight is 84.68.
Diketen aka acetyl ketene or ketene dimer. Flash point 35.2 ℃, 6.5 ℃ melting point, boiling point 127.4 ℃, the refractive index nD1.4379, relative density d201.0897, latent heat of evaporation 690.82 J/mol, generate heat 4.526 J/mol. Colorless transparent liquid with tear.
Diketene with ketene, same can occur with active hydrogen atom compounds of addition reaction, generate acetyl acetylate. Diketene reaction in the presence of catalyst and water, born into acetyl acetate. But it is not stable, immediately into acetone and carbon dioxide. The catalyst has a strong acid, strong alkali. Don't use the catalyst, the reaction in low temperature is not easy to, higher than 70 ℃ reactions can be performed. In the presence of alkali catalyst, generate acetoacetic ester reaction with alcohol.
Diketene with aromatic amine and ammonia, aliphatic amine, secondary amine reaction, generate acetyl acetanilide and acetyl acetyl amine. These are all dyes, pigments, medicine, pesticide intermediates. Diketene and halogen reaction, can generate gamma halogenated acetyl acetyl halide; The reaction with formaldehyde, the alpha, beta unsaturated ketones; Under the Raney nickel catalyst hydrogenation, generates beta butyrolactone; In the presence of aluminium trichloride, FriedelCrafts reaction with benzene, generate benzoyl acetone.
Diketene in less than 5 ℃ without aggregation, but high in mild acid, alkali and, under the existence of a certain salt easily aggregated into dehydroacetic acid, 2, 6 - dimethyl pyrone and 2, 6 - (6-2 - methyl - 4 - oxygen - methyl pyran base) pyrone. In addition, diketene through pyrolysis, generates ketene quantitatively.
Diketene ketene polymerization was prepared by the two molecules, industrial manufacturing method by diketene ketene absorption polymerization solvent, polymerization in temperature - 5 ~ 30 ℃.
Diketene purposes is used for acetoacetic ester, acetyl acetanilide, benzoyl acetone dyestuff, pigment, the medical medicine, fungicide, preservatives, resin stabilizer such as raw materials.
