Detection and toxicity modeling of anthraquinone dyes and chlorinated side products from a colored smoke pyrotechnic reaction

Green pyrotechnics seek to remove known environmental pollutants and health hazards from their formulations. This chemical engineering approach often focuses on maintaining performance effects upon replacement of objectionable ingredients, yet neglects the chemical products formed by the exothermic reaction. In this work, milligram quantities of a lab-scale pyrotechnic red smoke composition were functioned within a thermal probe for product identification by pyrolysis-gas chromatography-mass spectrometry. Thermally decomposed ingredients and new side product derivatives were identified at lower relative abundances to the intact organic dye (as the engineered sublimation product). Side products included chlorination of the organic dye donated by the chlorate oxidizer. Machine learning quantitative structure-activity relationship models computed impacts to health and environmental hazards. High to very high toxicities were predicted for inhalation, mutagenicity, developmental, and endocrine disruption for common military pyrotechnic dyes and their analogous chlorinated side products. These results underscore the need to revise objectives of green pyrotechnic engineering.

Automated summary

Green pyrotechnics aim to remove environmental pollutants and health hazards, but often overlook the formation of chemical products during exothermic reactions. Through pyrolysis-gas chromatography-mass spectrometry, new side product derivatives with lower toxicities were identified in a lab-scale pyrotechnic red smoke composition. Machine learning models predicted high toxicities for common military pyrotechnic dyes and their chlorinated side products, indicating a need to revise green pyrotechnic engineering objectives.