Solvent
A solvent is a liquid capable of dissolving other substances, forming a solution in the process. Common examples include water, ethanol, kerosene, and acetone, each serving various practical applications, such as in aerosol sprays, adhesives, and perfumes. The interaction between solvent molecules and solute molecules allows solutes to disperse and interact in a new mixture, with the effectiveness of a solvent often determined by its chemical nature—polar solvents dissolve polar substances better, while nonpolar solvents are more effective for nonpolar materials.
Historically, solvents have been utilized in various cultures for medicinal, cosmetic, and cleaning purposes. For instance, ancient Egyptians and Romans employed solvents in their practices, leading to the development of dry cleaning, which uses solvents other than water to treat delicate fabrics. However, many solvents are toxic and flammable, requiring careful handling and safety measures during use.
In addition to their industrial and practical uses, some solvents have been misused as recreational substances, leading to inhalation practices that can result in severe health consequences. This abuse can cause significant physical harm, including potential brain and organ damage, and carries risks such as sudden sniffing death syndrome. Overall, while solvents play essential roles in various fields, their use must be approached with caution due to their associated health risks.
Subject Terms
Solvent
Solvents are liquids that dissolve other substances. They are used in many products, including aerosol sprays, adhesives, and perfumes. Common solvents include water, ethanol, kerosene, and acetone. Because many solvents are flammable and toxic, they should always be handled carefully. Although solvents have many useful purposes, some solvents are abused as narcotics.
How Solvents Work
A solvent is any liquid that dissolves another substance. Chemists use specific terms when discussing solvents. A substance dissolved by a solvent is called a solute. The resulting mixture is called a solution. When something dissolves in a solvent, the substance is considered soluble. When it does not dissolve, it is considered insoluble.
Solvents dissolve solutes through chemical reactions. Solvent molecules are attractive to solute molecules. Because of this, solute molecules tend to break their bonds with one another and form new bonds with the solvent molecules. This process pulls the solute molecules apart, spreading them among the solvent molecules. However, it does not make the solute disappear. If the molecular bonds of a solute are too strong for a solvent to break, the solute is considered insoluble.
Polar solvents' molecules are positively charged on one side and negatively charged on the other. Nonpolar solvents' molecules are neutral. Polar solvents' molecules are more attractive to polar molecules than nonpolar molecules. This makes polar solvents better at dissolving polar substances. Similarly, nonpolar solvents are better at dissolving nonpolar substances.
Some solvents are stronger than other solvents, but stronger solvents are not always best. A useful solvent will dissolve one substance without dissolving another. For example, acetone dissolves nail polishes but not nails, and turpentine dissolves paints without dissolving the painted structure.
History of Solvents
Scientists know that several prehistoric societies used solvents. The ancient Assyrians used ethanol and methanol for medicinal purposes, and the ancient Egyptians used solvents to make cosmetics. Additionally, ancient Romans used lye and ammonia to clean stains out of clothing. This was the beginning of dry cleaning, which became a major force in the development of modern solvents.
When used as a solvent, water has a tendency to damage and dissolve delicate fabrics. Dry cleaning is the process of cleaning fabrics without using water. Liquids other than water are still used. However, the liquids are solvents that react strongly with common stains but do not harm delicate fabrics.
Modern dry cleaning began in 1845, when Jean-Baptiste Jolly's maid accidentally spilled kerosene on his tablecloth. When the kerosene dried, Jolly noticed that it had removed the stains from the tablecloth without damaging it. Inspired by this event, he opened a cleaning company that used kerosene and gasoline to remove stains from clothes. Jolly was the first person to use the term dry cleaning.
Many solvents are toxic and extremely flammable. The solvents used in early dry cleaning were no exception. Gasoline and other petroleum-based solvents caused countless fires. For this reason, governments outlawed dry cleaners from operating in some heavily populated areas. Other solvents commonly used in dry cleaning, such as trichloroethylene and carbon tetrachloride, later proved extremely carcinogenic.
When petroleum became scarce during World War II, dry cleaners developed the solvent perchloroethylene, commonly called perc. Because perc is nonflammable, it quickly became very popular. Perc is still used today, but some governments discourage its use as a cleaning agent because of its carcinogenic tendencies.
Dry cleaning was not the only industry to drive solvent research and development. In the early 1900s, the perfume industry popularized solvents by using them to dissolve substances into a liquid while keeping enough of the original substance intact to preserve its scent. The cleaning industry drove the development of organic solvents, including acetone and tetrachloroethylene. Aerosols use solvents to dissolve chemicals into a sprayable form, and adhesives use solvents to help the adhesive stay in liquid form during application. Artists use solvents like xylene and toluene to create paints, and they use turpentine to thin paints and clean brushes. Turpentine was later adapted for general paint removal.
Most solvents are toxic to humans and animals. Almost all solvents are dangerous to drink, and some are dangerous to touch. Many even produce toxic fumes. People working with solvents are usually required to wear special safety equipment.
Solvents as Narcotics
Early forms of solvent abuse can be traced back more than two hundred years. In the 1800s, upper-class Americans and Europeans held parties for inhaling nitrous oxide and ether. When inhaled, these chemicals cause a short but intense feeling of euphoria. Modern solvent abuse can be traced back to the 1950s, when American and European youths discovered that certain easily obtained solvents caused an altered mental state when inhaled. From the late 1970s onward, the practice became popular among young people. Studies show that 20 percent of American students have experimented with inhaling solvents by the time they reach the eighth grade.
Modern solvent abuse occurs in several ways. Abusers may sniff the substance itself (called "snorting"), inhale fumes from a material soaked in the substance (called "huffing"), or pour the substance into an airtight bag to breathe the concentrated fumes (called "bagging"). These methods produce an effect similar to drunkenness, along with visual distortions and occasional hallucinations. The effects normally last for no longer than forty-five minutes. Commonly abused solvents include adhesives, paint thinners, butane, and gasoline.
Intentionally inhaling solvents is very harmful. While physical dependence does not occur, psychological dependence sometimes does. Long-term abuse is damaging to the brain, kidneys, liver, heart, lungs, and bones. It may contribute to congestive heart failure, dementia, decreased reflexes, and brain stem atrophy. Additionally, short-term solvent abuse carries a risk of sudden sniffing death syndrome (SSDS). This occurs when the heart is shocked out of its normal rhythm and ceases to pump blood effectively, causing a heart attack. SSDS causes up to 50 percent of solvent abuse–related deaths.
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