N-bromoderivatives of N,N′-methylene-bis-acrylamide-crosslinked polyacrylamide gels as oxidizing reagents: a synthetic and structural investigation

✍ Scribed by Benny K. George; V.N. Rajasekharan Pillar

• Publisher: Elsevier Science
• Year: 1989
• Tongue: English
• Weight: 299 KB
• Volume: 25
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(89)90164-x

✦ Synopsis

Copolymers of acrylamide and N,N'-methylene-bis-acrylamide were prepared by free radical solution polymerization. The resulting crosslinked polyacrylamide gels containing 5, 10, 15 and 20% of the crosslinking agent were converted to the corresponding N-bromo derivatives by treatment with potassium hypobromite. The extent of bromination decreased with increasing amount of the crosslinking agent with a range of capacity from 7.3 mequiv Br/g of the resin for the linear polyacrylamide to 2.3 mequiv Br/g for the maximum crosslinked (20%) polyacrylamide gel. Alcohols were oxidized by the bromine-containing polymer to carbonyl compounds in 85-99% yield. The oxidation of benzoin to benzil was selected for investigation of the effect of the crosslink density on the reactivity of the oxidizing reagent. The interdependency of the extent of crosslinking, the hydrophobic-hydrophilic nature of the various solvent systems used and the reactivity were investigated. These studies revealed that the optimum condition for a specific extent of reaction can be arrived at only by judicious choice of the crosslink density, mechanical integrity of the particles, hydrophobic-hydrophilic nature of the solvents, solvent composition, molar excess of the polymeric reagent and temperature.