With Friedel-Crafts reagents

the polymerization of a series of aliphatic nitriles

including acetonitrile

propionitrile

n-valeronitrile

n-oenantionitrile and phenylaceto-nitrile

has been studied. The results show that the polymerization ability of these nitriles decreases with the increase of aliphatic chain-length. Polynitriles are a new type of conjugated polymer with the following chain structure: [(R)C = N]p

R = CH3

C2H5

n-C4H9

n-C6H13

C6H5CH2. The complexes of nitriles with metal halides

such as BF3

TiCl4 ets.

play an important role in the polymerization mechanism. The semi-conductivety and heat resistance of polynitriles were determined.