Selective catalytic oxybromination of hydroxyaromatic compounds
AssigneeGeneral Electric Company
InventorGrigorii Lev Soloveichik
Life of this patent
Estimating the term…
Abstract
A method for selectively brominating hydroxyaromatic compounds is disclosed. Hydroxyaromatic compounds are contacted with oxygen and a bromine source, in an acidic medium, in the presence of a catalyst selected from the group of compounds and mixtures of compounds of Group IV–VIII transition metals of the Periodic Table of Elements. The selectivity of mono-brominated products produced, predominantly in the para-position, from the method using transition metal compounds as catalysts is significantly higher than that of known methods using other catalysts. Thus, there is a significant reduction in the production of undesirable dibrominated and more highly brominated by-products.
Claims26
A method for preparing a brominated hydroxyaromatic compound which comprises contacting a hydroxyaromatic compound with oxygen and a bromine compound selected from the group consisting of hydrogen bromide, elemental bromine, ionic bromide salts, and mixtures thereof, in a polar solvent and an acidic medium, in the presence of a catalyst selected from the group of compounds and mixtures of compounds of Group IV–VIII transition metals of the Periodic Table of Elements.
A method for preparing 4-bromophenol, 4-bromo-o-cresol or 4-bromo-m-cresol, which comprises contacting phenol, o-cresol or m-cresol, respectively, with air and hydrogen bromide in a polar solvent and an acidic medium, in the presence of a catalyst selected from the group of compounds and mixtures of compounds of Group IV–VIII transition metals of the Periodic Table of Elements.
Dependencies are inferred from the claim text.