| 摘要 |
<p>Pure methyldichlorophosphine (MDCP) is sepd. from a mixt. of MDCP, PCl3, CCl4 and CHCl3 by (a) removing PCl3 and other low b.pt. fractions in a first-stage distn. (temp. at bottom of column is not >115 degrees C, not >105 degrees C) and (b) sepg. the MDCP from high b.pt. fractions in a second-stage distn. (temp. is not >120 degrees C, 102-110 degrees C). Before the first stage, 0.01-1% of an org. Ba cpd. (esp. mixt. of Ba sulphonate and Ba phenolate) or 0.1-10% (0.5-5%) of a non-ionic surfactant (esp. an ethoxylated 6-30C unbranched fatty alcohol, e.g. ethyleneoxide polymer) is dissolved in the mixt. Before the second stage, 1-10% (3-6%) of POCl3 is added to the fraction from the base of the first distn. column. MDCP is used as a starting material for the flame-resisting of fibres and plastics. It must be very pure if it is not to adversely affect the materials, e.g. by discoloring them. Usual method of prepn. of MDCP gives high % of impurities of similar b.pt. (viz. CCl4, PCl3). It is very difficult to separate them by distn. The present method overcomes these problems.</p> |
