2,4-Dichlorophenol → Bis(2,4-dichlorophenyl) phosphorochloridate

Participants

Reaction Steps

The title compound was prepared by the general method of Example 1 with the following modifications. (1) The molar ratio of 2,4-dichlorophenol to phosphorus oxychloride was increased from 1.33 to 1.85 by using 189.99 g (1.165 mole) of 2,4-dichlorophenol and 96.60 g (0.63 mole) of phosphorus oxychloride. (2) The reaction time at 120° was increased to about 24 hours. (3) The product was crystallized using a larger quantity of hexane (570 ml, or 3 ml per gram of starting 2,4-dichlorophenol) at -15°. Analysis by GLPC indicated 82% purity (by weight) of bis(2,4-dichlorophenyl)phosphorochloridate, with contamination by a trace of 2,4-dichlorophenyl phosphorodichloridate and 18% (by weight) of tris(2,4-dichlorophenyl)phosphate. The yield of the bis(2,4-dichlorophenyl)phosphorochloridate when corrected for purity was 125 g (53%). Subsequent reactions were unaffected by the presence of the tris(2,4-dichlorophenyl)phosphate, as illustrated by Examples 3 and 4.

Provenance & Evidence