Methyl dialkyl phosphine oxides prepn. - by converting hydroxymethyl dialkyl phosphines with carbon tetrahalides

摘要

Methyl phosphine oxides (I) of formula: (where R1 and R2 are 1-20C (1-4C), esp. 1-2 C alkyl, opt. substd. by inert gps. (pref. 1 gp.), esp. in the omega-posn., e.g., -CN or -OR3, where R3 is 1-10C (1-4C) esp. 1-2C alkyl, or halogen (Cl and/or F), or are HOCH2-gps.), are prepd. from hydroxymethyl phosphines of formula: at between -10 and +120 degrees C, opt. in an inert solvent, in the presence of a catalyst; the catalyst is not 1 wt.% of a carbontetrahalide of formula: (where (i) all the Hal are the same and are Cl or Br, or (ii) Hal1 is F, Cl or Br and Hal2-4 are Cl or Br and not 3 of the Hal are alike). After the reaction, the catalyst is distd. off and (I) is isolated. (I) are used in flame-resistant polyurethanes and as inters. for synthesis of flame-proofing agents and plant protection agents.