Chemical Properties
Colorless or white crystalline flakes. M.P. 93°C.
B.P. 213°C. Soluble in water (20°C 140g/L), miscible with alcohol and
most oils. Faint, camphorlike odor.
Uses
2,5-Dimethyl-2,5-hexanediol is used as an intermediate in the preparation of 2.5-Dimethyl-2.5-bis(tertbutyl-peroxy)hexane to produce polyethylene copolymers and polyethylene rubbers. It is also could be used to prepared nickel-containing Complex Reducing Agents (termed NiCRA)[1].
Uses
2,5-Dimethyl-2,5-hexanediol was used in the synthesis of six- and seven-membered heterocyclic boron compounds containing intramolecular N-B bond.
Preparation
The raw materials 2,5-Dimethyl-3-hexyne-2,5-diol (37.4 g, 263 mmol), ethyl acetate (60 mL), and Pd/C catalyst (0.285 g, 2.63 mmol, 1 mol %) were added to an autoclave. The hydrogen gas was slowly added to 10 bar. When the hydrogenation reaction was performed for 12 hours and then removed the hydrogen gas. Finally, 2,5-Dimethyl-2,5-hexanediol is obtained by purification.
General Description
2,5-Dimethyl-2,5-hexanediol on heteropoly acid catalyzed dehydration yields cyclic ethers via stereospecific intramolecular S
N2 mechanism. It reacts with nitriles in concentrated sulfuric acid to yield Δ
1-pyrrolines.
Purification Methods
Purify the diol by fractional crystallisation. Then the diol is dissolved in hot acetone, treated with activated charcoal, and filtered while hot. The solution is cooled and the diol is filtered off and washed well with cold acetone. The crystallisation process ia repeated several times, and the crystals are dried under a vacuum in a freeze-drying apparatus [Goates et al. J Chem Soc, Faraday Trans 1 78 3045 1982]. [Beilstein 1 IV 2600.]
References
[1] Feghouli G, et al. Activation of reducing agents. Sodium hydride containing complex reducing agents 29. Epimerization of alcohols by nickel-containing complex reducing agents (NiCRA). Tetrahedron Letters, 1988; 9: 285–290.
