Chemists Develop Environmentally Friendly Fireworks

Scientists are creating fireworks made of chemicals that don't pollute the atmosphere. These environmentally friendly fireworks could also offer better color quality and intensity than conventional fireworks.

Smoke after fireworks. Credit: Rolf BrobergSmoke after fireworks. Credit: Rolf Broberg Chemists Thomas Klapötke from the University of Munich in Germany and Georg Steinhauser from TU Vienna in Austria have investigated making fireworks out of nitrogen-rich compounds. Such fireworks would burn smoke-free, eliminating the massive black clouds that form on Fourth of July evenings.

When a conventional firework is set off, many pollutants fill the air, such as lead, barium, chromium, chlorates, dioxins, smoke and particulates, carbon monoxide, and nitrogen and sulfur oxides.

"For a long time, the consequences of this were not considered," Klapötke said. "In the meantime, scientists have been working on more environmentally friendly alternatives."

Conventional fireworks draw their energy from the oxidation of carbon. Clean fireworks, on the other hand, would get energy from the high temperatures that occur with the formation of nitrogen-rich compounds. Some possible compounds could be tetrazoles and tetrazines, which are made of four nitrogen atoms and either one or two carbon atoms, respectively.

To produce different colors, chemists could use aminotetrazole salts with specific non-toxic metals. For example, lithium, sodium, potassium, rubidium and cesium result in red, orange, violet, purple, and pink flames, respectively.

Somewhat ironically, the most difficult color to produce with "green" fireworks is green. The researchers are looking into green-burning salts based on copper compounds.

But the biggest challenge will likely be selling the fireworks at a competitive price. Klapötke things that, in order for clean fireworks to become a practical alternative, lawmakers must step in at first to make the fireworks more economical.

via: Innovations Report

Mar 18, 2008
by Anonymous

Environmentally friendly fireworks

While I laud the efforts of anyone to come up with less toxic fireworks compounds, there are significant inaccuracies in the article and formidable barriers to success. I believe the authors do not possess enough understanding of fireworks making nor the practicalities of fireworks use, to be qualified to make their proposition.

First, there are few, if any chromium compounds, used in modern fireworks. Second, the statement that "Conventional fireworks draw their energy from the oxidation of carbon" is a vast oversimplification of what takes place in various kinds of pyrotechnic reactions. I won't get into a detailed discussion of pyro chemistry, but there are many types of reactions occurring among many more elements than simply carbon.

The suggestion that cesium and rubidium could provide viable alternatives for today's coloring agents is absurd. Their toxicity alone discounts their viability, let alone their cost.

Even if pyrotechnically viable tetrazoles and tetrazines are developed, they would have to be cost competitive with the relatively low-priced compounds used in the fireworks industry today. And there would have to be some reason for them to be employed other than cost or viability. Pyrotechnic/fireworks compositions take years, sometimes, to develop and refine. This process is expensive because of the time involved. And once a fireworks company has a particular color-effect dialed in, they are loathe to abandon it.

Also, interations among fireworks compositions must be understood. Simply creating a tetrazine with a good enough "red" is not enough. The fireworks manufacturer has to understand what adverse reactions that composition might have with the other compositions used in the same firework device.

Since most of the world's fireworks are currently produced in China, then all of the above must take place there. But without incentives for the Chinese to make the change, and without foreknowledge of issues of safety and composition viability, it will not happen. It becomes a chicken or egg issue.

Regardless of what seemingly viable, eco-friendlier fireworks compositions are developed, the system, being what it is, is unlikely, if ever to adopt new replacements for compositions whose cost, safety, and efficacy have been developed over the past 200 years.

Harry Gilliam
Skylighter, Inc.