Patent DE564321 (http://l2.espacenet.com/dips/viewer?PN=DE564321&CY=gb&LG=en&DB=EPD)
trimethylphosphate
To 153 parts phosphorylchlorid, 250 parts methanol are added at -5°C with rapid stirring. The mixture is heated to 30°C for ~ 1h, cooled to room temp and part of the produced HCl removed with vacuum. The reaction product is then made alkaline by addition of dry sodium carbonate and the formed sodium chloride as well as salts of eventually developed acidic esters removed by filtration. After the excess alcohol is distilled off, the remaining ester is subjected to vacuum distillation. The trimethylphosphate is completely pure, bp 193°C/760mm.
The last sentence of the first example ,using n-BuOH, reads : "The yield is nearly quantitative" ;D
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