Pyrotechnic smoke has different applications, e.g., in road safety, for military use, or in movies. It can either obscure vision or be used to create color signals. However, some of the anthraquinone dyes currently used to produce colorful smoke are thought to be harmful to human health.

Vojtech Pelikan, University of Pardubice, Czech Republic, and colleagues have identified a less toxic, alternative to red anthraquinone dyes—the DPP pigment red 254 (PR254, pictured below), which has a brilliant red color and is less toxic than comparable anthraquinone dyes. Signal smoke is generally created by sublimation and subsequent condensation of the dye, which requires high thermal stability. The DPP pigments used are thermally stable up to over 400 °C and capable of sublimation.

The team showed that a pyrotechnic formulation containing PR254 reached a yield of red-colored smoke of 51 %, compared with 48 % for the reference anthraquinone dye disperse red 9 (DR9). PR254 is also more thermally stable than the reference dye, which might allow it to be used together with less toxic heat-generating systems, according to the researchers.

• Diketopyrrolopyrrole─A Greener Alternative for Pyrotechnic Smoke Compositions,
  Ondrej Zeman, Vojtech Pelikan, Jiri Pachman,
  ACS Sust. Chem. Eng. 2022.
  https://doi.org/10.1021/acssuschemeng.2c01000