Lipenan,Charpentier,France,1974
48.5 parts of ethyl 4'-chlorophenoxyisobutyrate are dissolved in 200 parts by
volume of dry toluene in the presence of 262 parts of 4-hydroxy-N,Ndimethylbutyramide and 2 parts of aluminum isopropylate. The solution is
heated for 8 hours, while collecting the toluene-ethanol azeotrope, in an
apparatus provided with a distillation column at a controllable rate of reflux.
After this it is filtered ,the solvent is evaporated in vacuo and the residue is
distilled. An almost colorless, slightly yellow oil is obtained, the purity of which
by chromatographic examination in the gaseous phase is of the order of
99.5%. Its boiling point is 175°C under 0.1 torr.
48.5 parts of ethyl 4'-chlorophenoxyisobutyrate are dissolved in 200 parts by
volume of dry toluene in the presence of 262 parts of 4-hydroxy-N,Ndimethylbutyramide and 2 parts of aluminum isopropylate. The solution is
heated for 8 hours, while collecting the toluene-ethanol azeotrope, in an
apparatus provided with a distillation column at a controllable rate of reflux.
After this it is filtered ,the solvent is evaporated in vacuo and the residue is
distilled. An almost colorless, slightly yellow oil is obtained, the purity of which
by chromatographic examination in the gaseous phase is of the order of
99.5%. Its boiling point is 175°C under 0.1 torr.
The product can be recrystallized. For this, it is dissolved, for example, at the
ambient temperature in petrol ether, ethyl ether or isopropyl ether, and this
solution is cooled at about -50°C while stirring. After drying over sulfuric acid
under vacuum, white needles of very great purity are thus obtained.
