Title: 5,5-Dimethyl-1,3-cyclohexanedione
CAS Registry Number: 126-81-8
Additional Names: 1,1-Dimethyl-3,5-diketocyclohexane; 1,1-dimethyl-3,5-cyclohexanedione; dimethyldihydroresorcinol; dimedone; methone
Molecular Formula: C8H12O2
Molecular Weight: 140.18
Percent Composition: C 68.54%, H 8.63%, O 22.83%
Literature References: Prepd from mesityl oxide and diethyl malonate: Shriner, Todd, Org. Synth. coll. vol. II, 200 (1943).
Properties: Needles from water, prisms from alcohol + ether. Dec 148-150°. Slightly volatile with steam (50 ml of a distillate contained 0.016 g). The dry crystals may be stored in a brown bottle for several years at room temp. Aq solns oxidize on exposure to air and light or upon prolonged storage in the dark. 100 ml of a satd aq soln contains 0.401 g at 19°; 0.416 g at 25°; 1.185 g at 50°; 3.020 g at 80°; 3.837 g at 90°. Monobasic acid in water. pK (25°): 5.15. Dipole moment 3.46. Also sol in methanol, ethanol, chloroform, benzene, acetic acid, and in 50% ethanol-water mixture.
pKa: pK (25°): 5.15
Use: For the separation and identification of aldehydes. Gives insol condensation products with aldehydes, but not with ketones. The use of piperidine as a catalyst is recommended. |