Dry ice, the solid form of carbon dioxide, has a history marked by two distinct phases: a scientific discovery in the early 19th century and a commercial invention nearly a century later. This material, prized for its extreme cold and residue-free cooling, became an industrial reality only after its properties were translated into a marketable product. Understanding its “invention” requires separating the initial observation of solid carbon dioxide from its later application as a practical cooling agent.
Defining the Substance: Carbon Dioxide in Solid Form
Dry ice is carbon dioxide (\(CO_2\)) frozen into a solid state. Its most notable characteristic is that it does not melt into a liquid like water ice; instead, it transitions directly from a solid to a gas in a process called sublimation. This property is why it is called “dry,” as it leaves no wet residue behind.
Dry ice is exceptionally cold, sublimating at \(-109.3^\circ\) Fahrenheit (\(-78.5^\circ\) Celsius). This extreme cold makes it a highly effective refrigerant, offering significantly more cooling power than traditional water ice.
The Scientific Discovery of Solid CO2
The first recorded observation of solid carbon dioxide occurred in 1835 by French chemist Adrien-Jean-Pierre Thilorier. Thilorier was experimenting with liquid carbon dioxide, which he produced under high pressure. When he released the pressure from a large cylinder containing the liquid, most of the \(CO_2\) rapidly evaporated.
The rapid evaporation caused a sudden drop in temperature, leaving behind a white, snow-like substance at the bottom of the container. Thilorier initially mistook this substance for frozen water vapor, but it was later confirmed to be solidified carbon dioxide. While this marked the moment the substance was scientifically identified, it remained a laboratory phenomenon for decades.
Transitioning from Discovery to Commercial Invention
Despite Thilorier’s discovery, solid carbon dioxide was not a commercially viable product for nearly 90 years. The transition from scientific curiosity to practical invention required the development of industrial processes and a market need for superior refrigeration. The commercial invention of dry ice is largely attributed to the American engineer Thomas B. Slate.
In 1924, Slate applied for a U.S. patent for the commercial manufacture and sale of solid carbon dioxide. He recognized the immense potential of its residue-free cooling for industrial applications, particularly for shipping perishable goods. The following year, Slate’s company, Prest-Air Devices, evolved into the DryIce Corporation of America.
The DryIce Corporation of America was responsible for building the first production plant and trademarking the term “Dry ice” in 1925, which cemented the substance’s common name. The initial commercial use involved selling the product to railway companies to keep train cars cool, replacing messy water ice in refrigeration units. This development in the 1920s represents the true invention of dry ice as a marketable, industrial product.
Why the Invention Still Matters Today
The commercial invention of dry ice revolutionized temperature-sensitive logistics and remains a fixture in modern industry.
Logistics and Shipping
Its primary role is as a cooling agent for transporting perishable items, such as frozen food, where its ability to sublimate without leaving liquid is invaluable.
Medical and Pharmaceutical Use
In the medical field, dry ice is relied upon for the preservation and shipment of biological samples, pharmaceuticals, and vaccines that require ultra-low temperatures.
Industrial Cleaning
It has also become a staple in industrial maintenance through dry ice blasting. This method uses pressurized pellets of solid \(CO_2\) to clean machinery and delicate electrical equipment without causing damage or leaving residue.