Piperonyl butylate prepn - from chloromethyldihydrosafrole and monobutyl diethylene glycol ether alkali metal salt

摘要

In the title process piperonyl butylate (I) is prepd by reacting an alkali metal salt of monobutyl diethylene glycol ether (II) and chloromethyldihydrosafrole (III) at 50 degrees C under an inert atmosphere, neutralising the mixt and distilling the mixt in vacuo to remove (II) and recover (I) as a residue distillation is effected at a temp prevent tar formation. (II) and (III) are only slightly coloured; (II) is prepd from a strong base and the ether at 90 degrees C in the presence of 1-5% amine esp. ethylene diamine and (III) by chloromethylating dihydrosafrole with HCHO and HCl, and treating the crude product with an alkane or cycloalkane to dissolve (III) and ppte the tars and finally removing the solvent (I) is synergistically effective with pyrethrin in insecticidal compsns.