SynopsisAnion exchange membranes with excellent durability were prepared by chemical modification of Nafion. The modification was achieved by transformation of the sulfonic acid group into quaternary ammonium group. Namely, Nafion membrane was first converted into an amide-type membrane. Reduction of the carbonxyl group to methylene followed by quaternarization with alkyl iodide resulted in the formation of an anion exchange membrane. The electric resistance of the resulting membranes depends on the equivalent weight of the starting membranes (4.4-6.0 12 cm2 in 0.5N NaCl). The characteristics of the membranes are the excellent stability toward chemical substances such as organic solvents, oxidizing agents, acids, etc. For example, the membranes are stable in aqueous saturated chlorine solution a t 60°C for 1000 hr.
S U M M A R Y :3-(9-Adenyl)-, 3-(3-adenyl)-, 3-(9-hypoxanthyl)-and 3 4 3-hypoxanthyl)-2-hydroxypropyl dihydrogenphosphates were condensed in the presence of a large excess of N.N'-dicyclohexylcarbodiimide (DCC). The major part of the oligomeric products is soluble in watcr and has a molecular weight of more than 1000 according t o gel-filtration measurement.The absorption spectra show 3 yo of hypochromism for mixtures of the oligo-3-(9-adenyl)-8-hydroxypropyl phosphate with denaturated yeast RNA or sperm DNA.
Z U S A M M E N F A S S U N G :3-(9-Adenyl)-, 3-(3-Adenyl)-, 3-(9-Hypoxanthyl)-und 3-(3-Hypoxanthyl)-2-hydroxypropyl-dihydrogenphosphat kondensieren in Gegenwart von iiberschiissigem N.N'-Dicyclohexylcarbodiimid. Die oligomeren Produkte sind in Wasser loslich, und die Hauptmenge hat ein Molekulargewicht von iiber 1000 (bestimrnt durch Gel-Filtration). Mischungen von Oligomerem 3-(9-Adenyl)-2-hydroxypropylphosphat untl RNA aus Hcfe oder DNA ails Sperrna zeigten cinen Hypochromie-ElTekt von 3 yo.
7‐(2′.3′‐Dihydroxypropyl)‐theophylline‐3′‐phosphate was synthesized using phosphorus oxychloride in trimethyl phosphate. This compound was condensed using N.N′‐dicyclohexylcarbodiimide as a dehydrating agent in refluxing dimethylformamide to oligomeric products which were separated into four peaks by chromatography using Sephadex G‐25. The major portion of the oligomeric product was found to have a molecular weight of more than 1000 according to gel‐filtration measurement. An oligomeric product was also obtained from the polycondensation of 7‐(2′.3′‐dihydroxypropyl)‐theophylline with phenoxyphosphoryl dichloride.
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