Reaction #470405

Reaction equation

hydrochloric acid

n-octanol

lithium methoxide

ethyloctylphosphite

dioctyl phosphite

sodium hydroxide

diethylphosphite

ethyloctylphosphite

dioctylphosphite

→

n-octyl phosphorous acid

Solvents

methanol

water

Conditions

Workup

1. 1
   workup.DISTILLATIONThe resultant mixture was then distilled under vacuum of 1.00 mBar
2. 2
   OtherAt 23° C. ethanol was removed
3. 3
   workup.DISTILLATIONAt 43-48° C., unreacted diethyl phosphite was distilled, with the remaining 65 g
4. 4
   Temperaturedid not require cooling
5. 5
   workup.ADDITIONhowever, the rate of addition
6. 6
   Otherdid not exceed 50° C
7. 7
   OtherTwo phases formed
8. 8
   Otherthe upper organic phase was separated
9. 9
   OtherThe n-octanol formed as a by-product of the reaction
10. 10
    Otherwas removed under vacuum

Procedure

50 g (0.38 mol) of n-octanol was premixed with 3.5 mL of a 2.2M solution of lithium methoxide in methanol. The mixture was rapidly added at room temperature to 53 g (0.38 mol) diethylphosphite. The colour of the solution changed from colourless to yellow. The resultant mixture was then distilled under vacuum of 1.00 mBar. At 23° C. ethanol was removed. At 43-48° C., unreacted diethyl phosphite was distilled, with the remaining 65 g comprising a 1.6:1 mole mixture of ethyloctylphosphite and dioctylphosphite. The mixture of ethyloctylphosphite and dioctyl phosphite was added slowly at room temperature to 26 g of a 50% sodium hydroxide solution in water. The reaction was exothermic but did not require cooling, however, the rate of addition was adjusted such that the temperature did not exceed 50° C. Afterwards the mixture was treated dropwise with concentrated hydrochloric acid until a pH of 2 was measured. Two phases formed and the upper organic phase was separated. The n-octanol formed as a by-product of the reaction was removed under vacuum leaving behind 49.8 g of n-octyl phosphorous acid as a colourless liquid containing small amounts of sodium chloride.

Source