10 Conversion of Graft Polyacrylamide to Amines via the Hofmann and Mannich Reactions R. J. ELDRIDGE Downloaded by UNIV OF QUEENSLAND on October 21, 2015 | http://pubs.acs.org Publication Date: June 10, 1980 | doi: 10.1021/bk-1980-0121.ch010
CSIRO, Division of Chemical Technology, South Melbourne, Victoria, Australia
Magnetic ion exchange resins have considerable advantages over conventional resins i n their handling properties (1)• They settle rapidly, permit high flow rates i n fixed bed plant, and can be pumped continuously without damage i n moving bed plant. By forming a shell of ion exchanger about a fine magnetic core, resins with very high reaction rates can be produced. Graft polymerization of monomers such as acrylic acid on core particles consisting of magnetic iron oxide embedded i n crosslinked poly (vinyl alcohol) (PVA) has been described previously
(A).
Magnetic weak base resins are of interest for a variety of water treatment applications. However, the attempted graft polymerization on magnetic PVA beads of diallylamine, methyldiallylamine, dimethylaminoethyl methacrylate and dimethylaminopropylacrylamide (as hydrochlorides) was unsuccessful. Attempts to prepare magnetic weak base resins by modification of grafted acrylic acid also failed. However acrylamide grafts readily to crosslinked PVA (2) and the Hofmann degradation of such grafts offers a possible alternative route. The Mannich reaction can also be used to introduce amino groups into magnetic polyacrylamide (PAM) beads. Hofmann Degradation of Polymeric Amides The preparation of (soluble) polyvinylamine by reacting PAM with hypohalite was attempted as early as 1944, but high convert sions have been reported only recently (3»4,5^6). Early work at high temperature (7) resulted i n a decrease i n the nitrogen content of the polymer from 19.7% to
