The Interaction of Nitrogen Monoxide with Pyrolysed Polyacrylonitrile

Abstract

The object of the work described herein has been to in­vestigate the interaction between nitrogen monoxide (NO) and pyrolysed acrylonitrile copolymer (PAN.P). This interaction has been established and studied in some detail over the tem­perature range 250 to 700°c. At the same time the feasibility of using PAN.P based catalysts for the removal of small quantities of NO, produced by the internal combustion engine, has been investigated. The initial work was concerned with depositing a film of polyacrylonitrile from solution onto a pelletised alumina support and converting this into a supported PAN.P catalyst having optimum NO removal activity. Kinetic studies indicated that at soo⁰c, 5,170 x 10-10 moles s-1m-2 of NO were removed when using 3,300 ppm NO in nitrogen flowing at 1000 cm3min-l through lOg of supported PAN.P. The NO removal rate increased with temperature giving activation energies between 33.9 and 39.9 kJ mole-1. The reaction appeared to be first order in concentration of NO and in surface area. Surface area measurements which were vital, involved the construction of a semi-micro B.E.T. apparatus. The activity of PAN.P was examined in the presence of other gases using both dynamic and static conditions. NO was not reduced by carbon monoxide in any significant quantity in the presence of PAN.P. Whilst activity persisted in the presence of oxygen, degradation occurred to an extent which renders the PAN.Pin its present form commercially unaccep­table A detailed analysis of reaction products and an examination of various properties of PAN. Pare reported. These results are used in a discussion of possible mechanisms of reaction