Cross-linking cyanide ions

Poly(4-vinylpyridine) resins 6 cross-linked with 9.6 % divinylbenzene and 68-82 % alkylated also have been tested as catalysts for reaction of 1-bromooctane with cyanide ion 81). The catalytic activities depended on the organic solvent in the order benzene > toluene > o-dichlorobenzene. No swelling data were reported, so it is not known if the activities correlate with the swollen volumes of the catalysts. 

The most important point about the alkyl halide reactivities in triphase catalysis is that the reactions which have the highest intrinsic rates are the most likely to be limited by intraparticle diffusion. The cyanide ion reactions which showed the greatest particle size and cross-linking dependence with 1-bromooctane had half-lives of 0.5 to 2 h and with benzyl bromide had half-lives of 0.13 to 0.75 h. The reactions of 1-bromooctane and of benzyl chloride which were insensitive to particle size and cross-linking had half-lives of 14 h and 3 h respectively. Practical triphase liquid/ liquid/solid catalysis with polystyrene-bound onium ions has intraparticle diffusional limitations. 

Erom the discussion in Section 11.1, it follows that carbonates such as EC, PC, DEC, and DMC can be used as common plasticizers for PAN-based gel elecfrolyfes. Ofher kinds of plasticizer can also be added, for example, ladderlike small molecules confaining -C=N groups, which can favor dissociation of the lithium salt, separation of Li+ ions by the PAN chains, an increase in the ionic conductivity, and reduction of polarization. When a composite plasticizer is added, the ionic conductivity at room temperature may be as high as 4 X IQ- S/cm, with a lithium-ion transference number of 0.6-0.7. However, at high temperature, PAN will cyclize and form a cross-linked structure or carbonize, but will not catch fire, so that gel electrolytes based on PAN have good flame retardant ability. It also reacts with water renmants in the solvents to produce poisonous hydrogen cyanide. 

---