The Lithium Salts of Bis(azolyl)borates as Strontium‐ and Chlorine‐free Red Pyrotechnic Colorants
Abstract
After concerns regarding the use of chlorinated material for pyrotechnic items had reinforced, the action of the U.S. Environmental Protection Agency on health concerns about strontium ushered in a new era in the production of red light. Lithium was shown to impart red color to a pyrotechnic flame, however only a very narrow selection of such formulations can be found in the literature. Dihydrobis(azolyl)borates are a well investigated, easily accessible class of materials which have been proven to be suitable as pyrotechnic coloring agents. With their high nitrogen contents such moieties should also meet the requirements of a low combustion temperature and a reducing flame atmosphere for a lithium‐based red‐burning composition. This work evaluates the capability of the lithium salts of dihydrobis(pyrazol‐1‐yl)borate, dihydrobis(1,2,4‐triazol‐1‐yl)borate, and dihydrobis(tetrazol‐1‐yl)borate to serve as red color imparters. The latter compounds were characterized by multinuclear NMR experiments, IR spectroscopy, elemental analysis, and single‐crystal X‐ray diffraction and were investigated with respect to their thermal stabilities as well as sensitivities toward various ignition stimuli.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Aug 08, 2019
- Source ID
- 10.1002/zaac.201900132
Entities
People
- Alicia M. W. Dufter
- Jörg Stierstorfer
- Magdalena Rusan
- Thomas M. Klapötke
Organizations
- Ludwig-Maximilians-Universität München
- Office of Naval Research Global
- Strategic Environmental Research and Development Program