Glycerol: An important chemical with wide industrial uses

Glycerol

Glycerol, also known as glycerin, is a simple polyol compound. With the chemical formula C3H8O3, it is a clear, odorless, colorless, viscous liquid that is widely used in pharmaceutical formulations, personal care products, and various industrial applications. It has unique properties that make it useful for a variety of purposes.

Chemical and physical properties

It has a sweet taste and is approximately 1.26 times as dense as water. Its boiling point is 290°C and melting point is 18°C, making it quite viscous at room temperature. Glycerol is hygroscopic in nature and is soluble in water and various polar organic solvents. It has three hydroxyl groups that interact significantly with other compounds through hydrogen bonding. It is stable, non-toxic, and does not undergo oxidation or combustion at room temperature. Its high boiling point, viscosity, and sweet taste make it an ideal candidate for various applications.

Sources

In nature, it is naturally produced by plants and animals. It is a by-product of fat metabolism and is present in trace amounts in foods like olive oil, butter, and fatty meats. It can also be synthesized from fossil fuels through the oleo chemical pathway. Commercially, itis most often produced as a by-product of soap and biodiesel production. The global market is dominated by supply from biodiesel and oleo chemical industries, with about 80% of crude glycerol being supplied by biodiesel producers alone.

Uses

Due to its sweet taste and versatile properties, it finds application across a wide range of industries:

Pharmaceuticals - It is commonly used as an emollient, solvent, and sweetening agent in cough syrups, elixirs, mouthwashes, ointments, creams, suppositories, and injectable formulations. It helps solubilize, stabilize, and preserve active pharmaceutical ingredients.

Personal care - It acts as a humectant in cosmetic products like shampoos, conditioners, lotions, soaps, and toothpastes. It prevents moisture loss from skin and hair. It provides lubrication and gives products a smooth texture.

Food industry - As a sweet-tasting, odorless ingredient, it is used as a thickening agent and humectant in various food items like chocolate, candy, processed meats, bakery products. It has applications in beverages, icings, syrups, marinades, etc.

Tobacco - It is frequently found in electronic cigarette liquids to mimic the mouth feel of cigarette smoke. It produces thicker vapor compared to ethylene or propylene glycol.

Industrial uses - Due to its non-volatile, high boiling point nature, glycerol serves as a precursor to resins, plasticizers, humectants, solvents, hydraulic and brake fluids. It acts as a protective covering for metals and prevents corrosion. It also provides lubrication in metalworking applications.

Other uses - It is useful as a moisturizer, solvent, and filler in products ranging from cosmetics to explosives. It finds applications in biochemical research laboratories as a cryoprotectant in solutions for cell, protein, and enzyme stabilization. It is also used in various food preservatives, medical devices, explosives, and more.

Environmental concerns and regulations

While glycerol production has grown exponentially in the past two decades driven by the biodiesel industry, its accumulation as waste has raised environmental concerns. As a highly polluting byproduct, crude glycerol was often dumped or incinerated directly by biodiesel producers in the past. This posed issues like clogging wastewater treatment systems and release of hazardous gases. Most countries have since implemented stricter regulations for its waste disposal and incentivized its commercialization. Environmental norms mandate its purification before disposal. There is also increasing focus on developing value-added applications to utilize crude glycerol sustainably.

Future outlook

With rising global demand for biodiesel as a biofuel, its output is projected to increase substantially. However, alternative raw materials including plant oils and animal fats can potentially supplement or replace crude glycerol supply sources. Development of novel glycerol derivatives, green conversion technologies, new end-use applications and recovery methods could further boost glycerol commercialization and support a circular bioeconomy. Its versatile properties and non-toxic nature position glycerol well for replacing toxic petrochemical derivatives in the future. Eco-friendly utilization of the abundant glycerol produced annually stands to deliver numerous economic and environmental benefits.

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About Author:

Money Singh is a seasoned content writer with over four years of experience in the market research sector. Her expertise spans various industries, including food and beverages, biotechnology, chemical and materials, defense and aerospace, consumer goods, etc. (https://www.linkedin.com/in/money-singh-590844163)

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