Pentafluorobenzaldehyde

Freshly distilled pentafluorobenzaldehyde is a colourless liquid with a strong odour; clear yellowish liquid after melting; a lachrymator; soluble in common organic solvents and practically insoluble in water.

Pentafluorobenzaldehyde was used as derivatization reagent in a study to develop a sensitive method for the determination of primary amines in sewage sludge by headspace solid-phase micro extraction and gas chromatography-tandem mass spectrometry. It was used in the synthesis of novel, high molecular weight fluorinated aromatic polymers.

Pentafluorobenzaldehyde is prepared by the reaction ofpentafluorophenylmagnesium bromide, iodide or chloride, or of pentafluorophenyllithium with ethyl-ortho-formiate or 3,4-dihydro-6-methyl-3-(para-tolyl)-quinazoline methiodide. Higher yields of pentafluorobenza1dehyde have been obtained by the reaction with N-methy1formanilide. Pentafluorobenzaldehyde may be prepared also by the reaction of pentafluorobenzonitrile with anhydrous SnClz in ethereal solution of HCl with subsequent hydrolsis of the intermediate (62% yield).

2,3,4,5,6-Pentafluorobenzaldehyde reacts with 5-(aryl)dipyrromethanes to form a variety of meso-aryl [26]hexaphyrins.

Pentafluorobenzaldehyde is oxidized when exposed to light and air. It should be kept in a tightly stopped dark container. Pentafluorobenzaldehyde is about ten times as toxic as benzaldehyde, therefore it should be handled with caution.