Process for the preparation of halobenzaldehydes

US5648551A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Holger Borchert · Offstein, DE
• Thomas Gerdau · Eppstein, DE
• Jens Weiguny · Freinsheim, DE

Key dates

• Filing date: Jan 26, 1996
• Grant date: Jul 15, 1997
• Expiry date: Jan 26, 2016

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C45/36
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

The invention relates to a process for the preparation of halobenzaldehydes of the formula (I): ##STR1## in which Hal is fluorine, chlorine, bromine or iodine and z=1, 2, 3 or 4, by catalytic gas-phase oxidation of a substituted toluene of the formula (II), ##STR2## by oxygen, which comprises carrying out the oxidation in the presence of a catalyst of the formula (III) EQU Me.sup.1.sub.a Me.sup.2.sub.b Me.sup.3.sub.c O.sub.x (III), in which Me.sup.1 is bismuth or vanadium, Me.sup.2 is at least one of the elements selected from the group consisting of lithium, sodium, potassium, rubidium and cesium, Me.sup.3 is at least one element selected from the group consisting of iron, cobalt, nickel, niobium, molybdenum, arsenic, tin, antimony, tungsten, tantalum, phosphorus, chromium, manganese, palladium, copper, zinc, cerium, silver, boron, samarium, barium, calcium, magnesium and rhenium, and the letters a, b and c represent an atomic ratio of the respective elements such that when a=1, b has a value in the range from 0.1 to 2 and c has a value in the range from 0.05 to 2, different values for b and c being possible for different elements Me.sup.2 or Me.sup.3.