What is Toluene?
Toluene, or also known as toluol, is an aromatic hydrocarbon. It can also be referred as methylbenzene, anisen, and phenyl methane. Toluene is a colorless and water-insoluble liquid. It has the smell that is often associated with paint thinners.
The chemical has the boiling point of 110ºC and melting point of -93ºC. Toluene is considered as a good solvent, which can dissolve other substances. The chemical occurs naturally in crude oil and in the tolu tree. Toluene can also be found in making coke from coal and as a byproduct in the manufacture of styrene.
History of Toluene
Toluene chemical was first isolated by a polish chemist named Filip Walter in 1837 through a distillation process of pine oil. He referred the chemical as rétinnaphte. In 1841, a French chemist named Henri Étienne Sainte-Claire Deville isolated a hydrocarbon from balsam of tolu. Deville recognized that the hydrocarbon that he isolated is similar to Walter’s rétinnaphte and to benzene.
Deville called his isolated hydrocarbon as benzoène. Jöns Jacob Berzelius, later, recommended the name toluin in 1843. In 1850, a French chemist named Auguste Cahours isolated a hydrocarbon from a distillate of wood, which he recognized as similar to Deville’s benzoène. Cahours later named the hydrocarbon as toluene.
What is Toluene Used for in Real Life?
Main use of toluene is as a precursor to benzene. That use is done via hydrodealkylation. Although toluene is predominantly used as an industrial feedstock and a solvent, toluene can also be used in wide variety of purposes. It also has numbers of commercial applications. Some other uses of Toluene in real life can be seen as listed below.
- Solvent: Toluene is a common solvent. It is used as a solvent for paint, paint thinner, contact cement, silicon sealants, many chemical reactants, rubber, printer ink, lacquers, leather tanners, disinfectants, and some model airplane glue. As a solvent, toluene is also used in carbon nanomaterial, such as nanotubes and fullerenes.
- Explosives: Toluene is used in the synthesis of Trinitrotoluene explosives (or more commonly known as TNT).
- Foam: Toluene is one of the base ingredients of toluene diisocyanate, which is used to produce polyurethane foams.
- Fuel: Toluene, for fuel purposes, can be used to boost gasoline fuels’ octane number for internal combustion engines. It can be used for both two-stroke and four-stroke engines. Toluene at 86% fueled all turbocharged engines in Formula one during the 1980s. That use of Toluene was first pioneered by the Honda team.
- Recreational use: Toluene, in the manner of recreational use, is used as an intoxicative inhalant. As an inhalant, toluene is known to have euphoric and dissociative effects.
- Biological use: Toluene can also be used for biological purposes. It is used in the breaking of red blood cell in order to extract the hemoglobin in biochemistry experiments.
- Agricultural sectors: For agricultural purpose, Toluene is used against roundworms and hookworms.
- Cement: Toluene can be used as a cement for fine polystyrene kits.
- Coolant: Toluene is known to have the capability of good heat transfer. Because of its capability, it is used in nuclear reaction system loops.
- Production of Coca-Cola syrup: Toluene has also been used in the production of Coca-Cola syrups. It is used in the process of removing the cocaine from coca leaves.
- Pharmaceutical uses
- Dye production
- Fullerene indicator
- Cosmetic nail products
- Fingernail cleaner
- Spot removers
- Correction fluid
- Radiator fluid
- Production of Benzene
- Production of nylon
- Synthesis of benzoic acid
- Synthesis of benzoyl chloride
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Potential Health Risks that may be Caused by Toluene
Although toluene can be beneficial at times, it does not mean that toluene does not have health risk for us. The harmful effects of Toluene can be exposed to us by inhaling, direct contact, and ingestion. The toxicological effects of Toluene have been studied extensively. Some effects of toluene can be seen as listed below.
- Irritation in the eyes
- Irritation in the nose
- Irritation in respiratory tract
- Dilated pupils
- Lacrimation (which is discharge of tears)
- Muscle fatigue
- Numbness of the skin
- Tingling of the skin
- Color vision loss
- Hearing loss
- Loss of appetite
A prolonged and repeated exposure of toluene can bring us more dangerous effects. The effects may vary from organ damages to death. Those harmful effects include:
- Liver damage
- Cardiac abnormalities
- Removal of natural lipids from the skin (which leads to dry and fissured dermatitis)
- Kidney damage
- Central nervous system depression
- Decreased memory
- Incoordination with staggering gait
- Skin paresthesia: Skin paresthesia is a condition where a person feels an abnormal sensation, such as tingling, tickling, pricking, numbness, or burning on their skin with no apparent physical cause.
- Respiratory problem
- Pregnancy problems: Pregnant women who breath toluene in high levels leads to several pregnancy problems, like birth defects and retard mental abilities in children.
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Bioremediation of toluene
Toluene may have numerous harmful effects that affects us. But, those harmful effects of toluene can be reduced using bioremediation. Bioremediation is a process of treating contaminated organism or environment by altering the environmental conditions to stimulate the growth of microorganisms and degrade the target contaminant.
There are several types of fungi that can be used as bioremediation of toluene, such as Cladophialophora, Exophilia, Leptodontium, Pseureudotium zonatum, and Clasdosporium sphaerospermum. There are also several types of bacteria that can be used for similar purposes. Those microorganisms can degrade toluene. They used toluene as a source of carbon and energy.