| 摘要 |
An improved process for manufacturing tetrakis (hydroxymethyl) phosphonium amide condensation product without the formation of a precipitate. Urea or thiourea is added to the tetrakis (hydroxymethyl) phosphonium salt having an anion formed from a dibasic or tribasic or polybasic acid. The said salt is in aqueous solution. The pH of the aqueous solution of said salt is adjusted to the range of 4-6.5 when the urea or thiourea is added to the salt. The proportion of said salt to said urea or thiourea is 1:0.05-0.5 (molar). The sulphuric acid salt is preferred. The process produces an improved aqueous product substantially free of insolubles. |
