Those Enduring Room Deodorizers Montfort A. Johnsen, Ph.D. technicAl eDitor People have been battling noxious household odors since ancient times—first with open fires, then with open windows, flowers, pots of formulated masking fragrances, wick products and even ozone generators. When aerosols arrived on the scene in 1947, they offered new opportunities to combat bad odors. The first entries were simply about 1% fragrance, 24% odorless petroleum distillate and 75% CFC propellants. Major aerosol products were Florient, Renuzit and Wizard air fresheners. There was some reduction of the offending malodors, since a portion of these gases could be dissolved by the millions of airborne aerosol particles, which eventually fell to the floor but often remained obvious. Once the spray settled, or was slowly ventilated out of the room, many bad odors returned since they could be regenerated by such sustainable sources as smoking, dog beds and kitchen waste products. Many of these lingering malodors were created by microbes, as Joseph Lister discovered in 1838. He used sodium hypochlorite (NaCIO) and other oxidants to destroy these “billions” of invisible contaminators and got clean air as a result. By 1931, researchers discovered that resorcinol solutions could be atomized and used to purify air. In 1940, a 10% solution of 4-hexylresorcinol in 90% propylene glycol was developed. It was remarkably effective, even at concentrations of 0.0002g. per cubic foot of air. The product was used to protect Brits packed into underground London air raid shelters during the Nazi V2 missile attacks of 1942 and 1943. By 1948, triethylene glycol (TEG) was discovered as an ideal air sanitizer. A level of 0.0002g. per cubic foot of air, delivered as a very fine mist at humidities of about 15 to 45%, was able to kill about 85% of non-spore microorganisms after one minute, and about 99.9+% after three minutes. Compatibility problems prevented the commercial use of TEG in aerosols for over half a century. Rather interestingly, other glycols, various disinfectants and practical oxidants show little or no ability to sanitize air. With rare exceptions, they have not been included in air freshener formulations. The period from 1948 to 1955 was hallmarked by a huge growth in aerosol air fresheners. Major marketers, such as Colgate-Palmolive (Florient), Gulf Oil (GulfSpray) and S.C. Johnson (Glade) were popular. Contrary to a primitive survey report, U.S. volume reached about 61 million units in 1955. Aerosol laboratories struggled to create better and cheaper formulations. The true aerosol deodorizers were first developed during these turbulent years. The Deodorizer Gamble An air freshener deodorizer is defined as a chemical or mixture that has the ability to either suppress or eliminate malodors by direct interaction. It is often difficult to differentiate them from germicides, sanitizers and disinfectants, which are employed (in part) to kill those micro-organisms that produce bad odors. Also, they are not simple aldehydes and “neutralization” compounds, which can anesthetize the trigeminal and olfactory nerves. Unpleasant odors can arise from dozens of activities routinely conducted in houses. A few of the most common are cooking odors, body odors (humans and pets), putrefaction odors and those from smoking. The strongest and most repulsive are those from the low valance sulfur atoms in hydrogen sulfide, alkyl and aromatic thiols (mercaptans), sulfides and disulfides. Offensive odors from low valence nitrogen atoms include ammonia, alkyl amines and diamines (as putrescine) and occasionally such aromatics as pyridine, pyrazine, pyrithione and pyrazole. Miss America of 1945 Bess Myerson promotes Colgate’s Florient label-free air freshener in 1962. 26 Spray October 2015
Spray October2015
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