essentially odorless, and then mixed it with a chlorofluorocarbon (CFC) blend of about the same pressure,
maintaining the non-flammability of the blend. It was called Propellant A and was an immediate success. An
air deodorant formula would be:
Early Air Deodorants with Propellant A (Circa 1955)
n 7.0% Triethylene Glycol (Air Treatment Grade)
n 0.2% Fragrance
n 7.8% Odorless Mineral Spirits (OMS)
n 85.0% Propellant A
June 2020 SPRAY 25
• 45.0% CFC-11
• 45.0% CFC-12
• 10.0% Isobutane (Aerosol Grade)
During 1954 and 1955, the fledgling aerosol industry became very interested in flammability. Under
the Chairmanship of Clarence “Pete” Clapp, a Flammability Committee was formed within the Chemical
Specialties Manufacturers Association (CSMA—the forerunner of the current Household & Commercial
Products Association HCPA). In collaboration with Dr. R.A. “Bus” Fulton of the Interstate Commerce
Commission (ICC), three test methods were devised: Flame Propagation Test, Closed Drum Test and Open
Drum Test. They were used to develop formulations that were marginally non-flammable, mainly by reducing
the costly, non-flammable CFC propellants. Since the triethylene glycol formulas had vanished by this time,
the new compositions were far simpler:
Air Deodorant with Propellant A & More OMS
n 1.0% Fragrance
n 24.0% Odorless Mineral Spirits (OMS)
n 75.0% Propellant A
• 45% CFC-11
• 45% CFC-12
• 10% Isobutane (Aerosol Grade)
The level of fragrance changed from about 0.25% to 1.50% according to its odorous
intensity. One major marketer preferred a blend of 45% CFC-11 and 55% CFC-12 to achieve
a slightly smaller particle size. The Gulf Research & Development Co. used its parent company’s
Gulflight odorless distillate instead of OMS, since the two were virtually indistinguishable.
Deodorizing additives
While fragrances could replace or mask unpleasant odors to varying degrees, the industry was
anxious to actually destroy odors, if possible. One possibility was to add a compound with an
electron-deficient area, which would then attract electron-rich odorant sites. The covalently
connected bad odor and deodorant would then have little or no odor. The osmophoric
(bad odor) site would include divalent sulfur (-S-) and trivalent nitrogen (-N=) locales. Other
mechanisms have been proposed, including absorption. There are more than 50 U.S. patents
touting the ability of various compounds to suppress bad odors.
One early counter-odorant was cocoyl methacrylate, trade named Metazene. It is mainly
a mixture of lauryl, myristyl and hexadecyl methacrylates. The supplier is Alpha Aromatics,
Inc. and it can be purchased in various strengths, including 100%. The deodorizer was a
commercial item as early as about 1945. It is typically used in aerosols at about 2.0%, but has
many other applications as well.
Another venerable deodorant is trade named Meelium, said to have been developed and
sold originally by the Gulf Oil Co. Its composition is unknown, although a phenanthrolene
ring structure is rumored. It is currently marketed by Alpha Aromatics. It exists as a dark red
liquid, typically about 40% active and almost odorless.
As mentioned, a veritable constellation of other purported deodorants have been described.
Some have been marketed, such as 3,5,5-trimethylhexanal, various geraniols and
fumerates. Most languish in U.S. Patents, where information about their odor-suppressing
abilities is generally quite vague.
Water-based air fresheners
The relatively high cost of the CFC propellants spurred the industry to look for alternative
non-flammable formulations. In 1960, a Danville, IL filler devised one. It contained about
61% of de-ionized water, so it was called “water-based.” This major advancement saved
Air Wick 4in1 Air
Freshener from Reckitt
Benckiser comes in premium
fragrances, such
as Vanilla Indulgence.