| abstract |
In phosphonic- and phosphinic acid prepn. by hydrolysis of the esters, catalysted by the acids formed, hydrolysis is effected under a higher pressure, pref. under autogenous pressure at 105-235 degrees C. The reaction mixt. contains at least double molar water quantity w.r.t. molar quantity of acidic OH gps. forming and/or present. The acids are used as corrosion-inhibitors and sequestering agents or as intermediates for the prodn. of corrosion-inhibitors, sequestering agents, flame-retardants textile auxiliaries and anti-statics. High saponifification rates are achieved. Discolouration and decompsn. of the acids at high reaction temps. e.g. above 150 degrees C is prevented. The dissociated alcohols may be recovered without conversion to dialkyl ethers. Water excess maintains dilution of reaction mixt. and reduces relative volatility of light esters, so that separation from alcohol-water mixts. distilling off is obviated. Pure acids and alcohols are recovered in quantitative yields. |