Propane provides heat and energy for millions of homes, vehicles, and appliances across the world. Known chemically as C3H8, this simple three-carbon alkane is a component of liquefied petroleum gas (LPG) valued for its portability and clean-burning properties. Propane’s journey from a nuisance in early gasoline production to a standalone commercial energy source was driven by the need to stabilize a volatile product and the realization that a waste product held significant value.
The Volatility Problem in Early Gasoline
The early 20th century saw a dramatic increase in the demand for gasoline, but the product itself posed significant challenges for producers and consumers. Natural gasoline, extracted from crude oil, contained a mixture of various hydrocarbons, including those with very low boiling points like propane and butane. These lighter components made the entire batch dangerously volatile.
High volatility caused the gasoline to easily evaporate, or “boil off,” during transport and storage in non-pressurized containers. This resulted in substantial product loss and financial strain for suppliers. Furthermore, the evaporating gases built up pressure inside barrels and tank cars, creating a significant safety hazard.
The highly volatile elements made the fuel unstable and inconsistent, which was problematic for the nascent automotive industry requiring a predictable energy source. Chemists focused on improving the safety and stability of commercial gasoline by finding a way to safely remove and utilize these offending components.
Isolation and Identification by Walter Snelling
The solution to the gasoline volatility problem came from Walter O. Snelling, a chemist working for the U.S. Bureau of Mines around 1910. Snelling began investigating why a newly purchased batch of gasoline was rapidly losing volume, a common complaint at the time. He observed that the pressure from escaping vapors in a glass jug of volatile gasoline repeatedly forced the cork out of the container.
Snelling correctly diagnosed that the rapid evaporation and pressure buildup were caused by the lighter hydrocarbon gases dissolved in the liquid gasoline. He then devised a scientific method to separate these highly volatile gases from the main gasoline mixture to stabilize the remaining liquid fuel. Using a process involving low-temperature and high-pressure techniques, Snelling successfully isolated a mixture of these gases, including propane and butane.
By 1911, Snelling produced relatively pure propane, chemically identifying it as a distinct energy source. This breakthrough solved the instability issue in gasoline by removing the fast-evaporating components. Snelling’s work transformed this problematic waste product of the refining process into a potential commercial fuel.
Transition to Commercial Fuel
Following the successful isolation of the gas, the next step was making the product commercially viable by containing it as a liquid. Snelling and his colleagues worked on methods to liquefy the propane and butane mixture through compression, allowing for safe storage and transport in steel cylinders. This concept of a portable, bottled fuel source was a major innovation, particularly for areas without access to piped natural gas.
Snelling secured a patent for his process of liquefying petroleum gas in 1913, a fundamental step in legitimizing the new fuel source. This patent covered the process for creating what would later be known as liquefied petroleum gas, or LPG. The name “propane” itself was derived from the chemical structure of the gas, taking the prefix “prop-” from propionic acid, which has three carbon atoms.
Snelling, along with others, established the American Gasol Company in 1912, marking the first commercial venture to market this newly isolated fuel. This company was founded to commercialize the process of bottling propane for applications such as lighting, cooking, and metal cutting. The transition from a byproduct that caused instability to a marketable commodity officially began, paving the way for the modern propane industry.