Weiming Qiu

Preparation of perfluorocarbon polymers containing phosphonic acid groups

Abstract Several co- and ter-fluoropolymers based on tetrafluoroethylene (TFE) and perfluorovinylethers, such as CF2=CFO(CF2)2P(O) (OC2H5)2, CF2=CFO(CF2)3P(O)(OC2H5)2, CF2=CFOCF2CF(CF3)O(CF2)2P(O)(OC2H5)2 and CF2=CFOC3F7, were synthesized via redox-initiated emulsion polymerization. The products were subjected to acid hydrolysis and the corresponding fluorinated polymeric phosphonic acids were obtained. Both the polymeric phosphonates and phosphonic acids can be readily processed into films by compression molding. Perfluorinated phosphonic acid membranes with an ion-exchange capacity (IEC) within the range 2.5–3.5 milliequivalents per gram and a thermal stability of 300–350 °C were prepared. The characteristics of these acid membranes were explored, and these films show promising electrochemical properties, such as proton conductivity.

A facile and general preparation of α,α-difluoro benzylic phosphonates by the CuCl promoted coupling reaction of the (diethylphosphonyl)difluoromethylcadmium reagent with aryl lodides

Abstract A series of α,α-difluorobenzylic phosphonates have been prepared in good yield (65–88%) by the CuCl promoted coupling reaction of the (diethylphosphonyl)difluoromethylcadmium reagent with aryl iodides.

The preparation of (EtO)2P(O)CFHZnBr and (EtO)2P(O)CFHCu and their utility in the preparation of functionalized α-fluorophosphonates

The organometallic reagent, (EtO)2P(O)CFHZnBr, was generated in situ in excellent yields via the reaction of (EtO)2P(O)CFHBr with zinc metal. Metathesis with Cu(I)Br gave (EtO)2P(O)CFHCu. The reagents exhibit excellent reactivity with substrates, such as allyl halides, alkynyl halides, vinyl halides, aryl halides and acyl or phosphoryl halides, and provide a useful one flask route to functionalized α-fluorophosphonates.

A useful synthesis of ω-iodoperfluoroalkanesulfonyl fluorides and perfluoroalkane-α,ω-bis-sulfonyl fluorides

Abstract ω-Iodoperfluoroalkanesulfonyl fluorides and perfluoroalkane-α,ω-bis-sulfonyl fluorides have been prepared via deiodosulfination, chlorination, and then chlorine-fluorine exchange reaction of α,ω-diiodoperfluoroalkanes I(CF2)nI (n=3, 4, 6). Similar reaction of I(CF2)2O(CF2)2SO2F affords FSO2(CF2)2O(CF2)2SO2F.

Preparation of α-fluorophosphonates

Abstract Two approaches to the preparation of α-fluorohosphonates are described. The first approach involved the free radical addition of (EtO) 2 P(O)CFBr 2 to alkenes followed by reduction of the addition adducts with Bu 3 SnH. The second approach utilized the Pd(PPh 3 ) 4 or Cu(O) catalyzed addition of (RO) 2 P(O)CFHl to alkenes followed by Zn/NiCl 2 ·6H 2 O reduction of the addition adduct.

Synthesis of novel partially fluorinated phosphonic/sulfonic acids

Abstract A new synthesis of (EtO) 2 P(O)CH 2 OCH 2 CHCH 2 ( 1 ) has been developed. Addition ofI(CF 2 ) 4 SO 2 F or I(CF 2 ) 2 O(CF 2 ) 2 SO 2 F to 1 followed by hydrolysis, reduction and ion exchangeof the addition adducts gave (HO) 2 P(O)CH 2 O(CH 2 ) 3 (CF 2 ) 4 SO 3 H·2H 2 O and (HO) 2 P(O)CH 2 O(CH 2 ) 3 (CF 2 ) 2 O(CF 2 ) 2 SO 3 H·3H 2 O,respectively.

Synthesis and reactions of 3,3-difluoroallylphosphonates and 3,3-difluoroallyltriphenylphosphonium bromide

Abstract 3,3-Difluoroallyltriphenylphosphonium bromide (1) and 3,3-difluoroallylphosphonates, 2, have been prepared by the reaction of CH2CHCF2Br with phosphites or triphenylphosphine in good yield. Wittig reaction of 1 with aldehydes gave the corresponding dienes (ArCHCHCHCF2) 4; however, Wadsworth-Emmons reaction of 2 with aldehydes failed to produce the dienes.