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The power of a drop of carbon tetrachloride: Why was it once the star of fire extinguishers?
Carbon tetrachloride, scientifically known as tetrachloromethane, once became an important component of fire extinguishers in the 20th century. However, over time, this widely used chemical has gradually withdrawn from history due to environmental and safety concerns. stage. This article will explore the properties, historical uses and hazards associated with carbon tetrachloride, and how it emits heat in fire extinguishers.
Basic properties of carbon tetrachloride
Carbon tetrachloride (CCl4) is a colorless liquid with a sweet chloroform smell, high density and non-flammable. Its molecular structure has tetrahedral symmetry, with four chlorine atoms evenly distributed around the carbon atoms, making it a non-polar compound. As a solvent, it is good at dissolving non-polar substances such as fats and oils, and is volatile, emitting vapors that exhibit the characteristics of chlorinated solvents.
Historical applications
Carbon tetrachloride was first synthesized in 1820 and was initially used for a variety of commercial purposes, including as a dry cleaning agent and refrigerant. Carbon tetrachloride fire extinguishers have been available since 1902, and this type of fire extinguisher became widely used in the 1910s. At the time, it was generally believed that carbon tetrachloride extinguished fires by displacing oxygen around the fire, but subsequent research found that it actually achieved this goal by inhibiting chemical chain reactions.
Safety and environmental impact
Over time, however, the use of carbon tetrachloride began to raise safety and environmental questions. Exposure to high concentrations of carbon tetrachloride may damage the central nervous system and cause degeneration of the liver and kidneys. Long-term exposure may even be fatal. To make matters worse, it breaks down at high temperatures to produce toxic chlorophosphoric acid, which has been responsible for many deaths.
According to the World Health Organization, carbon tetrachloride may promote the formation of hepatocellular carcinoma in mice and rats, but there is insufficient evidence of carcinogenicity in humans.
Gradually withdrawing from the stage of history
As awareness of the health and environmental effects of carbon tetrachloride grew, the compound's use declined sharply in the 1980s, especially after the Montreal Protocol and its use in making chlorofluorocarbons. Use was banned and production was significantly reduced in 1992.
Impact on modern society
Today, the use of carbon tetrachloride is restricted in almost all fields. Looking back on the glorious history of carbon tetrachloride and its widespread use, people have to reflect on whether scientific and technological progress can really improve efficiency. while eliminating harm to the environment and humans?
Summary
Although carbon tetrachloride was once the star of fire extinguishers, people have begun to abandon this "superstar" due to concerns about its safety and environmental impact. This also reflects cautious attitudes towards chemical use and increased demand for safer alternatives. Can this kind of history serve as a warning for the future, so that we will not ignore the importance of safety and environmental protection while advancing science and technology?
