Preparation of ion-exchangers by cross-linking of strach or polygalacturonic acid with 1,3-bis(3-chloro-2-chloro-2-hydroxypropyl)imidazolium hydrogen sulphate

摘要

The reaction conditions for cross-linking of starch (S) or polygalacturonic acid (PGA) with 1,3-bis(3-chloro-2-hydroxypropyl)imidazolium hydrogen sulphastein thepresence of NaOH and water were studied in terms of the moalr ratio of the reactioncomponents,the yields of water-insoluble product,the nitrogen content and the BCHIHS conversion.The optimum for S-derivatives was at themolar ratio of S/BCHIHS/NaOH/H_2O=0.01:0.02:0.04:0.333 with 348% yield on the amount of used S,7.71% nitrogencontent and 78% conversion of BCHIHS.Analogically on PGA the optimum was at PGA/BCHIHS/NaOH/H_2O=0.005:0.005:0.1:0.2 with 125% yield,7.99% nitrogen content and 63% conversion.Thelinkageof dihydroxypropylimidazolum(DHPI) groups was confirmed by NMR in solution on watersoluble products as well as by `(13)C solid-state NMR and FTIR on insoluble products.Under the used conditions muchmore NaOH is consumed on PGA while the yields of water-insoluble materials are lower than on S.The calculated T_(1p)(H) relaxation times gave similar values obtained previously on different polysaccharides cross-linked withdifferent cross-linkers.The elemental composition of samples in different cycles confirmed theionic interaction between the quaternary ammonium group and the PGA carboxyls.