SynopsisHalomethylation of polysulfone ( P S ) with C8H170CH2X ( X = Cl, Br) in the presence of SnX4 ( X = C1, Br) led to PS-CH2X ( X = C1 or Br or both) (Scheme 1 ) . Under controlled conditions, PS-CH,X could be isolated and retains the good film forming properties of PS itself. Interhalogen exchange reactions occur in the presence of SnX, ( X = C1, Br) under anhydrous conditions (Scheme l ) , or a quaternary ammonium phase transfer catalyst R*R3N+X -, under aqueous conditions (Scheme 2 ) . The exchange reactions with R*R,N+X -, are favored when R = C8-Clo, and with R = C, only if n-octanol is added; otherwise gelation occurs. Exchange in CHC13 is attributed to dehydrohalogenation (and generation of dichlorocarbene) of the solvent in the presence of tetrabutyl ammonium hydroxide. Further chemical modifications of PS-CH2X by reaction with strong nucleophiles, led to hydroxymethyl polysulfone, acetoxymethyl polysulfone, and t-butyl-oxymethyl polysulfone (Scheme 3). Hydroxymethyl polysulfone sometimes gels under basic hydrolytic conditions and is best obtained by methanolysis of PS-CH,-OAc. Both PS-CH,-OAc and PS-CH20t-Bu are very stable, and provide a way to generate PS-CH2Br on need by cleavage with HBr in acetic acid.Direct oxidations with DMSO or tetrabutyl ammonium dichromate (Scheme 4 ) or indirect oxidations (Scheme 5 ) produce polysulfone with pendent CHO, COzR and P03R groups. Finally, polysulfones with linker arms including, carboxy alkyl, hexaglycol or sulfonamido crowns are described (Scheme 6). The reaction products were characterized by 'H-and 13C-NMR. Double irradiation experiments, proved unequivocally, that the first substitution occurred on the B ring of the bisphenol A moiety (see Table I ) ; the second substitution occurs on the A ring in position a.Thermogravimetric analysis generally shows for all modified polysulfones an extra transition at a lower temperature. The area of this band agrees generally with the values expected from calculated substitution degrees. t Present address: Bar-Ilan University,
Chloromethylmethyl ether (CME) and bis-chloromethyl ether (BCME) are very convenient and efficient chloromethylating reagents, yet they are listed as carcirogens.' BCME is more notorious than CME. Consequently, several attempts have been made to synthesize CME free of BCME,, or iodomethyl-methyl ether free of BCME,3 or to introduce alternative reagents such as methylal/chlorosulfonic acid,4 or to generate incipient halomethyl furonium ion from l-chloro-4-chloro-(bromo)methoxy butane and 1,4-bis-[chloro(bromo)methoxy b~t a n e ] . "~ Short-chain chloromethyl-alkyl ethers were studied in the alkylation of aromatic compounds, but not as chloromethylating reagent^.^ Long chain chloromethylalkyl ethersgJO were described as intermediates on the way to cationic surfactants'J2 or alkoxymethyl sucrose surf act ant^.'^ No attention was given to their use as halomethylating agents or to the generation of BCME during their preparation. RESULTSWe wish14 to report the BCME-free synthesis of long chain halomethylalkyl ethers, ROCH,X, and their application in halomethylation of aromatic substrates and polymers, according to the following reactions:
Amidoalkylation of polysulfone (PS) with N‐chloromethylphthalimide (CMPi) to polymer 2/2a (PiPs), followed by hydrazinolysis of PiPs in CHCl3 with neat N2H4 + H2O (RT 3 days) to aminomethylpolysulfone (3, AMPS). Condensation of AMPS with 4‐chlorosulfonylbenzo‐18‐crown‐6 produced B18C6AMPS. Okawara‐type condensations with diglycydyl glycols (5) led to azacrown polysulfone polymers 6d, and polystyrene azacrown polymers 6a–6c. Products were characterized by 270 MHz 1H‐NMR, thermogravimetric (TGA) and DSC analysis. Insoluble aminomethylpolystyrene beads were used as model supports to study the Okawara‐type reaction with diglycydyl ethers and the products showed thermoregulated complexation of alkali salts on polymers 6b and 6c. Polysulfone membranes were prepared from B18C6AMPS and transport of K+ in a liquid membrane‐type experiment was demonstrated.
SynopsisStrong morphologic variations were noted in the chloromethylation of styrene copolymers incorporating TAT or DVB as crosslinking agents. In the first case control over the chloromethylation conditions (solvent, temperature, time) can he applied in order to mold the final porous structure of the chloromethylated polymer. In the case of XE-305 containing higher concentration of crosslinking agent, the chloromethylation conditions have a less, but still significant, effect on the structure and functional group distribution of the product. Under conditions of low ratios of chloromethylating agent (CME) or catalyst (SnCld), the chlorine incorporation figures are medium, but chlorine distribution through the cross section of the bead is more or less homogeneous. Increase in the above ratios results in increased chlorine concentrations, but also in higher degree of secondary crosslinking and uneven chlorine distribution profiles. Preselection of the experimental conditions enables calculated introduction of functional groups. In the case of TAT-styrene copolymers, controlled experimental conditions are used to form a porous structure with low and high chlorine distribution. Such a porous polymer can then be functionalized by other reactions. Under certain chloromethylation conditions, the chloromethylated TAT-styrene copolymer is aminated to produce anion exchange resins, without further morphological changes. INTRODUCTIONChloromethylated styrene-DVB copolymers are important intermediates on route to anion exchange resins1 and as such are used in water purification systems. As polymeric reagents they are engaged in the automatic polypeptide synthesis by the Merrifield method2 as well as a starting material for a host of other polymeric reagent^.^ Taking an interest in the role of the polymeric matrix during various reactions of polymeric reagent^,^ Warshawsky and Kalir5 have recently reported on the irreversible structural reorganization of flexible styrene-divinylbenzene (DVB) networks during the Friedel-Crafts alkylation with 5-chloromethyl-8-hydroxyquinoline in the impregnated (dry) state.In the present study, we report on aspects of structural transformations observed by stereoscanning electron microscopy (SEM) in two kinds of polystyrene matrices: first, very striking transformations in 1% hexahydro-l,3,5-triacryloyl-S-triazine (TAT) styrene copolymer6 during chloromethylation by the method of Schwachula and Hauptmann7; second, the crosslinking and morphologic changes in DVB-styrene copolymer (XE-305) during chloromethylation with chlorodimethyl ether. The experimental results point to the significance of the chloromethylation reaction conditions in producing ion exchange resins Journal of Applied Polymer Science, Vol. 25,2241Vol. 25, -2263Vol. 25, (1980 of good ion diffusionMore important, the chloromethylation conditions can be controlled to produce anion exchange resins of prescribed porosity. EXPERIMENTAL Chloromethylation of XE-305Amberlite XE-305, 5 g, was preswollen in 35 ml CHC13 (ethanol-free) f...
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