6. Conclusion

The presence of trace impurities in chemicals presents a hazard when a very rapid or exothermic decomposition or polymerization reaction is possible. Representative examples of such process conditions are documented in this article concerning organic nitro derivatives and two reactive monomers, vinyl acetate and ethylene oxide. These two examples are representative of other unstable substances and reactive monomers.

The undesirable effect of the presence of certain impurities in raw materials used in the chemical industry has been illustrated by two well-known examples: the presence of nitrogen trichloride in chlorine production, and the presence of hydrogen sulfide and mercaptans in petrochemical raw materials. These two examples are also representative of problems encountered in the chemical industry.