2,2-DIMETHYL-3,5-HEXANEDIONE

2,2-DIMETHYL-3,5-HEXANEDIONE Property

Melting point:

105-106 °C

Boiling point:

165 °C

Density 

0.912 g/mL at 25 °C

refractive index 

1.4600

Flash point:

57°C

storage temp. 

Sealed in dry,Room Temperature

pka

pK1:10.01 (25°C)

form 

liquid

Specific Gravity

0.918

color 

colorless

Water Solubility 

3.327g/L(25 ºC)

BRN 

969813

CAS DataBase Reference

7307-04-2

Safety

Hazard Codes 

Xn

Risk Statements 

10-22

Safety Statements 

23-24/25

RIDADR 

1224

WGK Germany 

3

HazardClass 

3

PackingGroup 

III

HS Code 

29141990

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Warning

Hazard statements

H226Flammable liquid and vapour

H302Harmful if swallowed

Precautionary statements

P210Keep away from heat/sparks/open flames/hot surfaces. — No smoking.

2,2-DIMETHYL-3,5-HEXANEDIONE Chemical Properties,Usage,Production

Chemical Properties

Clear colorless to pale yellow liquid

Uses

5,?5-?Dimethylhexane-?2,?4-?dione is a useful reactant for the synthesis RhIII and IrIII half sandwich compounds which had good antimicrobial properties against Mycobacterium smegmatis.

Synthesis

The general procedure for the synthesis of 5,5-dimethylhexane 2,4-dione from pinacolone and ethyl acetate was as follows: pinacolone (2 g, 20 mmol) was dissolved in ether (2.4 mL) and slowly added dropwise to a stirred mixture of sodium hydride (0.96 g, 40 mmol, 60% oil solution) in anhydrous ethyl acetate (3.3 mL, 40 mmol), with the time of the addition being was controlled at 60 min to maintain a suitable reaction rate. The temperature was maintained at 40-50 °C by gentle heating in an oil bath during the reaction. If the reaction is too violent during the titration, the titration can be suspended and a small amount of ethanol can be added to ease the reaction. After complete addition of pinacolone, the reaction mixture was continued to be stirred at 40-50 °C. To maintain the fluidity of the reaction mixture, an additional 20 mL of ether was added. Upon completion of the reaction, the mixture was cooled to room temperature and diluted with sufficient amount of ether. Subsequently, ethanol was added and stirred for about 20 minutes to quench the unreacted sodium hydride. After cooling to room temperature again, the mixture was slowly neutralized by adding ice water and an appropriate amount of HCl, controlling the temperature to be below 20 °C. After neutralization is complete, stirring is continued until all solids are dissolved. The ether phase was separated and the aqueous phase was extracted with ether. The combined ether extracts were washed sequentially with NaHCO3 solution and water. After removal of the solvent under reduced pressure, the residue was purified by ball-to-ball distillation (60 °C, 10 mmHg) to afford the target product 5,5-dimethylhexane 2,4-dione as a colorless liquid (2.61 g, 54% yield).

References

[1] Journal of Organometallic Chemistry, 2014, vol. 776, p. 89 - 97
[2] Journal of Organometallic Chemistry, 2015, vol. 776, p. 89 - 97
[3] Journal of the American Chemical Society, 1934, vol. 56, p. 2665,2666
[4] Journal of the American Chemical Society, 1950, vol. 72, p. 1352,1353, 1356
[5] Comptes Rendus Hebdomadaires des Seances de l'Academie des Sciences, 1910, vol. 150, p. 928