Naphthalene

Some things look like white snow.

This white stuff has a strong smell. It can keep bugs away from clothes. People used it in mothballs. It helps keep your things safe.

Most of this stuff comes from coal tar. Coal tar is a thick liquid.

Scientists found it a long time ago. They learned how it is made. It is made of two rings joined together.

This substance can be used to make many things. It helps make paints and dyes. It can even help make strong concrete.

It is a very useful part of our world.

Naphthalene is a white solid that looks like crystals.

It has a very strong smell. You might know it as the main part of old mothballs. These mothballs work by letting out vapors. These vapors can be toxic to moths. This helps keep insects away from clothes in sealed boxes.

Scientists studied naphthalene a long time ago. In 1826, Michael Faraday found its chemical formula. It is made of two rings joined together. We call these benzene rings. Because the rings are joined, it is called a polycyclic aromatic hydrocarbon.

This means it is a group of rings that share atoms.

Most naphthalene comes from coal tar. Coal tar is a thick liquid. A process called distillation is used to separate it. This way, workers can pull the naphthalene out.

Today, it is also made from petroleum.

Naphthalene helps make many useful things. It is a starting part for making phthalic anhydride. This chemical helps make paints and varnishes. It also helps make strong concrete. Some parts of naphthalene help make dyes for cloth. It can even help make medicines.

Naphthalene is a white, crystalline solid that has a very strong smell.

You might recognize its scent from traditional mothballs. It is a special kind of substance called a polycyclic aromatic hydrocarbon. This means it is made of rings of atoms that are joined together. Specifically, naphthalene is made of two benzene rings that are fused. Fused means the two rings share atoms to stay connected. This unique shape makes it very important in the world of science.

The way naphthalene is built is quite interesting. The two rings are flat, which scientists call being planar. Because the rings are joined, the bonds between the atoms are not all the same length. Some bonds are about 1.37 Å long, while others are about 1.42 Å long. There are eight carbon atoms that are not shared by the rings. Each of these atoms holds one hydrogen atom. These atoms are numbered 1 through 8 around the outside of the molecule.

People have been studying this substance for a long time. In the early 1820s, people first reported finding this white solid. They found it by using a process called distillation on coal tar. In 1821, a man named John Kidd described how to make it. He gave it the name naphthaline because it came from naphtha. Later, Michael Faraday found its chemical formula in 1826. In 1866, Emil Erlenmeyer suggested its ring structure. Carl Gräbe confirmed this structure three years later.

Most naphthalene today comes from coal tar. Coal tar is a thick liquid that contains about 10% naphthalene by weight. Workers use distillation to pull an oil out that contains about 50% naphthalene. This oil is washed with chemicals to clean it. After another step called fractional distillation, the crude naphthalene is about 95% pure. Some naphthalene is also made from petroleum. In North America, companies like Koppers Inc. and Monument Chemical Inc. produce it.

Naphthalene is used to make many everyday items. Its biggest use is making phthalic anhydride. This chemical helps create plasticizers for PVC and resins for paints. Naphthalene also helps make dyes for coloring cloth. Some of its parts are used to make medicines, like a type called beta blockers.

It can even be used as a way to protect museum items from insects. It is a very helpful building block for many different industries.

Naphthalene is an organic compound with the chemical formula C10H8. It is the simplest form of a polycyclic aromatic hydrocarbon, which means it consists of multiple rings of atoms joined together.

Visually, it appears as a white crystalline solid. It is also famous for its very strong, characteristic odor. This scent is so powerful that humans can detect it at concentrations as low as 0.08 parts per million by mass. Because of its ability to turn into a gas, it has historically been used as a fumigant in mothballs to protect clothing from insects.

At the molecular level, naphthalene is composed of two fused benzene rings. In organic chemistry, rings are considered fused when they share two or more atoms.

This structure makes naphthalene a benzenoid polycyclic aromatic hydrocarbon. The molecule is planar, meaning it is flat like a sheet of paper. While benzene has bonds that are all the same length, naphthalene is different. The carbon-carbon bonds alternate in length. Some bonds, such as C1-C2, are about 1.37 Å long. Other bonds are slightly longer, measuring about 1.42 Å.

This specific geometry is consistent with the theorem of cross-conjugation.

The symmetry of the molecule creates different types of positions for other atoms to attach. There are two sets of equivalent hydrogen atoms: the alpha positions and the beta positions. The alpha positions are numbered 1, 4, 5, and 8. The beta positions are numbered 2, 3, 6, and 7.

Because of this arrangement, scientists can create different isomers. An isomer is a molecule with the same formula but a different structure. For example, if you attach one group to an alpha position, you get a different result than if you attach it to a beta position. Other molecules, like azulene, also feature fused rings but use a different 5–7 ring system instead.

The history of discovering naphthalene involves several important scientists. In the early 1820s, researchers reported finding a pungent white solid through the distillation of coal tar. In 1821, John Kidd described the substance's properties and how to produce it. He named it "naphthaline" because it was derived from naphtha, a term for volatile hydrocarbon mixtures. In 1826, the scientist Michael Faraday determined its chemical formula. Later, Emil Erlenmeyer proposed the two-ring structure in 1866. This structural model was confirmed by Carl Gräbe in 1869.

Today, naphthalene is produced on a massive industrial scale. The global market for naphthalene has reached approximately 2.25 million tons. Most of this comes from the distillation of coal tar. Typical coal tar contains about 10% naphthalene by weight. During industrial processing, workers distill the tar to create an oil containing about 50% naphthalene. After washing the oil with sodium hydroxide and sulfuric acid, fractional distillation is used. This results in crude naphthalene that is about 95% pure.

In North America, companies like Koppers Inc. and Monument Chemical Inc. are major producers.

Naphthalene serves as a vital chemical precursor for many industries. Its single largest use is the production of phthalic anhydride. This chemical is an intermediate used to make resins for paints and varnishes. It is also used to create plasticizers for polyvinyl chloride, known as PVC. Beyond plastics, naphthalene derivatives are used to make various synthetic dyes and pigments. Some specific derivatives, such as naphthalenesulfonic acids, are used to create rubber processing chemicals. They are even used in the production of lead-acid battery plates and agricultural pesticides.

In the medical and specialized fields, naphthalene plays a surprising role. Certain derivatives are used in the synthesis of pharmaceuticals. For example, some naphthalene-based structures help create beta blockers, which are medicines used to treat heart conditions.

Naphthalene also acts as a powerful solvent. In its molten, liquid state, it can dissolve aromatic compounds that are otherwise very difficult to melt or mix. This makes it a useful tool in complex laboratory reactions, such as the reaction between C60 and anthracene. Even in nature, trace amounts of naphthalene can be found in certain plants, like magnolias, and even in some species of deer.