Question

When acrylic polymers are burned, toxic fumes are produced. For example, in many airplane fires, more passenger deaths have been caused by breathing toxic fumes than by the fire itself. Using polyacrylonitrile as an example, what would you expect to be one of the most toxic, gaseous combustion products created in the reaction?

Short answer

One of the most toxic gaseous combustion products created in the reaction of polyacrylonitrile is hydrogen cyanide (\( HCN \)). This compound is extremely toxic and can be lethal even in small concentrations, posing a significant threat to life in fire situations involving acrylic polymers.

Step-by-step solution

Identify the structure of polyacrylonitrile

Polyacrylonitrile is a polymer with a chemical structure that can be represented by the following repeating unit: (CH2=CH-CN)n It contains carbon, hydrogen, and nitrogen atoms.

Understand the combustion process

Combustion is a chemical process involving the reaction of a fuel with oxygen, which usually produces water and carbon dioxide as products, along with the release of heat and light. In this case, polyacrylonitrile, an organic polymer, serves as the fuel. The combustion process may produce a variety of other products depending on the chemical structure and composition of the fuel.

Predict possible combustion products

During combustion, polyacrylonitrile may break down and partially or fully react with oxygen. As a result, various compounds may form, such as: \( H_2O \) (Water), \[\] \( CO_2 \) (Carbon dioxide), \[\] \( CO \) (Carbon monoxide), \[\] \( NO \) (Nitric oxide), \[\] and \( HCN \) (Hydrogen cyanide). Comparing the toxicity of these compounds can help us identify one of the most toxic gaseous products.

Assess the toxicity of predicted combustion products

The compounds listed in the previous step have varying levels of toxicity. Water and carbon dioxide are harmless and essential to life. While carbon monoxide and nitric oxide are toxic, they are not the most toxic products produced during the combustion process. Hydrogen cyanide, however, is an extremely toxic gas that can be lethal even in small concentrations. Therefore, we can expect hydrogen cyanide to be one of the most toxic, gaseous combustion products created in the reaction.

Conclusion

Given the structure and composition of polyacrylonitrile and the nature of the combustion process, one of the most toxic gaseous combustion products created in the reaction is hydrogen cyanide. This compound is extremely toxic and can be lethal even in small concentrations, making it a major threat to life in the event of a fire involving acrylic polymers.