Antifreeze may be the unsung hero of winter time. Antifreeze is actually a critical solution in more places than you might realize. We usually think of antifreeze in the liquid that cools car engines, but it is also used for other applications including heating systems, air conditioning systems, ice skating rinks, refrigeration systems, solar energy units, and more.
Today, antifreeze is synonymous with ethylene glycol, but this wasn’t always the case. In this article, we’ll learn how antifreeze works, and what makes ethylene glycol the ideal candidate for antifreeze solutions.
How does antifreeze work?
Antifreeze solutions exploit the principle of freezing point depression and boiling point elevation, which you may or may not recall from high school chemistry. Here’s a reminder of how it works.
When you add most chemicals to water, it creates an expanded liquid temperature range. Water will usually freeze at 0 degrees Celsius, and boil at 100 degrees Celsius. But when we create an aqueous solution of water with most other chemicals, the new solution will usually freeze at a lower temperature and boil at a higher temperature, which means that it will remain a liquid over a wider range of temperatures. This is the case when we add ethylene glycol to water, expanding the operative range.
Some examples of antifreeze chemicals include salts (like calcium chloride), alcohols (like ethanol, isopropanol, and methanol), and glycols (like ethylene glycol).
The story of antifreeze
Water is a useful substance for many operations because it has a high heat capacity, wide availability, and low cost. The only drawback is the narrow temperature range in which it exists as a liquid. From early days, it was useful to create aqueous “antifreeze” solutions to solve this shortcoming. This is paramount not only in the winter, when heat-transfer systems like cars need to operate efficiently, but also in high summer temperatures for other equipment.
Salt is perhaps the most familiar and visible antifreeze additive, since we can actually see it on the streets in the winter time, preventing them from icing over and creating dangerous conditions. Salts were some of the earliest choices for antifreeze solutions, since they are cheap and readily available. However, they had a significant disadvantage for some applications because they corrode metal.
Alcohols were another early choice. The problem with alcohols, however, was their low boiling points, which meant they would easily evaporate during the warm summer months. This created maintenance and cost issues. They are also highly flammable, creating potentially hazardous conditions.
Ethylene glycol was first used as antifreeze as early as 1925. These kinds of systems are sometimes called “permanent antifreeze” because there was no risk of evaporative loss of ethylene glycol, unlike with alcohols. (Water vapor is actually lost more easily than ethylene glycol.) It also eliminated the flammability concerns associated with alcohol-based antifreeze solutions.
For these reasons, ethylene glycol gradually took over the antifreeze market. By the 1960s, ethylene glycol-based antifreeze solutions comprised 90% of the market in automotive use.
Although ethylene glycol is the major component of antifreeze (along with water), other additives help to create the ideal solution for each application. For example, other additives may be included to minimize corrosion and foaming in automotive engines.
Although ethylene glycol is the predominant antifreeze chemical in the United States, its use remains limited in Europe due to toxicity concerns. However, it is worth noting that ethylene glycol is biodegradable in most waste treatment facilities. If there are concerns about high concentrations of heavy metals picked up from the heat-transfer system, it can also be recycled for reuse.
Benefits of ethylene glycol for antifreeze solutions
Ethylene glycol has risen to the top as the predominant antifreeze chemical thanks to multiple advantages, summarized here:
• Less corrosive compared to salt solutions, making it suitable for automotive applications
• Does not evaporate as easily as alcohols, making it suitable for warmer seasons
• Does not pose flammability concerns, unlike alcohols
• Has efficient heat-transfer properties
• Readily biodegradable in most waste treatment plants in the absence of heavy metals
• Can be recycled for minimal environmental impact
Where to buy ethylene glycol?
Lab Alley is proud to be your go-to supplier for all of your chemical needs. We keep lab grade, 99% ethylene glycol in stock and ready to ship for all of your industry needs. We also offer a range of sizing options to perfectly suit your business, from small to bulk sizing. Shop now on our easy-to-navigate website, with no-hassle ordering, transparent pricing, and speedy delivery.
