| 摘要 |
<p>of the disclosure: 2,5-Dioxo-1,2-oxa-phospholanes of the formula (I) (I) wherein R1 is an organic radical and R2 and R3 each also means organic radicals or hydrogen, are prepared by reacting 2-halogeno-formylethyl-phosphinic acid halides of the formula (II) (II) wherein R1, R2 and R3 are defined as in formula (I) and X means Cl or Br, preferably Cl, with an approximately equimolar quantity of acrylic acid. The compounds (II) may also be produced in the reaction batch and in situ by reacting about equimolar quantities of a dihalogenophosphine of the formula (III) (III) with an .alpha.,.beta.-unsaturated acid (IV) CHR2=CR3-COOH (IV) In the formulae (III) and (IV) R1, R2, R3 and X are defined as indicated above. In the reaction there is formed, in addition to the compounds (I), practically exclusively .beta.-halogenopropionic acid and no free hydrogen halide. The phospholanes (I) are valuable flame retarding agents for plastics, intermediates, for example, for the synthesis of biocidals etc. - 1a</p> |
