Bayer Aktiengesellschaft

Karl-Julius Schmidt

Ingeborg Hammann

Wilhelm Stendel

Bernhard Homeyer

Hellmut Hoffmann

Peter Siegle

Friedrich Schmidt

Gert Hansen

In the preparation of a phosphoric acid alkyl ester dichloride by reacting phosphorus oxychloride with an aliphatic alcohol according to the equation ##STR1## in which R represents C.sub.1 -C.sub.5 -alkyl, the improvement which comprises carrying out the reaction continuously at a temperature of about 10.degree. to 50.degree. C. using an excess of phosphorus oxychloride of about 5 to 40%. The excess phosphorus oxychloride is reacted with the alcohol by continuous mixing, the reaction mixture is cooled, substantially all the hydrogen chloride formed is then separated off in a preliminary degassing stage, the reaction mixture is worked up in a distillation column, the unreacted phosphorus oxychloride and any diluent is separated off over the top and condensed, the condensate is recycled to the reaction and the corresponding alkyl ester dichloride is removed continuously as the bottom product.

Continuous preparation of phosphoric acid alkyl ester dichlorides

O-Alkyl-O-[8-chloro-quinoxal-2-yl]-thionoalkanephosphonic acid esters of the formula ##STR1## in which R and R.sup.1 each independently is alkyl with 1 to 6 carbon atoms, which possess arthropodicidal, especially insecticidal and acaricidal, properties.

O-Alkyl-O-[8-chloro-quinoxal-2-yl]-thionoalkanephosphonic acid esters

7-Bromoquinoxal(6)yl-(thiono)-(thiol)-phosphoric acid esters and ester-amides of the formula ##SPC1## In which

7-Bromoquinoxal-6-yl-(thiono)-(thiol)-phosphoric and (phosphonic) acid

O-(4-iodophenyl) (thiono) phosphoric (phosphonic) acid esters and ester amides of the formula ##SPC1## In which

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Karl-Julius Schmidt