Water → 3,5-Dimethyl-1-hexyn-3-ol

Participants

Reaction Conditions

Reaction Steps

A solution of 12.6 g of 3,5-dimethyl-1-hexyn-3-ol (Aldrich Chemical Co.)(o.1 mole) and 1.5 g of t-butyl peroctoate dissolved in 35 g of denatured ethanol was added dropwise over 3.1 hours to a stirred solution containing 21.2 g of sodium hypophosphite monohydrate (0.2 mole), 40 g of denatured ethanol and 20 g of deionized water. The temperature was maintained at 80° C. throughout the addition. After completion of the addition, heating at 79°-80° C. was continued for 4.8 hours longer. A fine white precipitate formed in the reaction mixture during the addition and post heating. The reaction mixture was cooled and the precipitate was filtered off using a sintered glass funnel. The precipitate was washed on the funnel several times with fresh ethanol, air dried on the funnel for 2 hours and finally was dried in a vacuum oven at 1 mm Hg and 60° C. for 24 hours. Dry weight of the precipitate was 21.8 g, a white solid. The filtrate was concentrated on a rotary evaporator and then dried in a vacuum oven at 1 mm Hg at 60° C. for 22 hours to leave 9.6 g of a brittle, puffy, white solid. The precipitate was analyzed by 13C and 31P NMR and was identified as nearly pure disodium 3,5-dimethylhexyl-3-ol-1,1-diphosphinate, the product resulting from 1,1-diaddition of hypophosphite to the acetylenic bond of 3,5-dimethyl-1-hexyn-3-ol. Phosphorous 31NMR analysis of the dried filtrate from the reaction showed that about half of it was unreacted hypophosphite and the remaining half was organophosphorous compounds, probably 1,2-diadduct of hypophosphite to the acetylenic compound. Neglecting organophosphorous compounds in the filtrate, the yield of the main product was 72.2%.

Provenance & Evidence