There are many other malodorous chemicals, such as unsaturated aliphatics (as propene) and the lower aliphatic carboxylic acids (as butyric acid). They are more difficult to control except by selective absorbtion polymers. Fortunately, these are rarely encountered in houses. Experimental work to create chemical deodorants dates back to at least the 1940s. During that period, L.B. Kilgore developed and patented an ester now known as lauryl methacrylate and more generally by the tradename Metazene, owned by Alpha Aromatics, Inc. Made entirely by reactions of natural materials, about 73% is derived from coconut oil. The basic structure is shown in the graphic here. The R group, from coconut oil, varies in composition as would be expected. The lauryl group (C12) comprises about 60 to 65%, followed by the myristyl group (C14) at 25%–30% and the palmityl group (C16) at about 10%. Very small amounts of unwanted other R groups, such as caproyl (C10) and stearyl (C18), are almost completely removed by center-cut vacuum distillation—typically 192°C and 4mm. Hg. Additions of from 0.01 to 0.50% of hydroquinone, hydroquinone monomethylether or other strong reducing agents were found necessary to deter Metazene from oxidative polymerization. After completing extensive performance and toxicological tests, the Rohm & Haas Co. brought Metazene to the market in 1950. When included at 2% in the anhydrous aerosol air fresheners of the period, a 10-second spray was said to produce an average of about 86% deodorization. Metazene itself is a pure, water-white, virtually odorless liquid. Initially, it was marketed in 40 to 80% strengths, using odorless petroleum distillate diluents for stability, but current preparations are 99.5%. The success of Metazene inspired a wave of further research. Around 1952, chemists at the Gulf R&D Co. in Harmersville, PA began examining mixtures of sulfonated polycyclic oil well still bottoms for possible malodor counteraction. While their work has remained confidential, they achieved good control of many bad odors by using a complex blend, thought by some people to contain partly hydrogenated phenanthrolone disulfonates. The light brown liquid was trademarked Meelium and contained 60% of the deodorant mixture in an almost odorless aliphatic petroleum distillate. For several years, it was used at about 3% in GulfSpray room deodorant. The product faced heavy competition from other marketers and its new (at the time) water-based deodorant formulation was sold, first to the Prentiss D&C Co., Inc., and then to Alpha Aromatics, Inc. Today, it remains a well-respected and well-advertised deodorizer option, available in several concentrations, including 100% purity. Around 1960, Dr. K. Kulka and his team at Dodge & Olcott, Inc. (later Fritzsche Brothers, Inc.) began working on deodorizers. By this time, the molecular structure R—O-CO— CH==CH- had become of interest because “electron sinks” at both ends resulted in the central (C+) carbon atom developing a significant positive charge. As such, it could attract negatively charged sulfur (S) atoms and nitrogen (N) atoms of malodors. Once captured, the malodor would be neutralized. The composite particles would then be ventilated out of the room, or, if it was over about five microns in diameter, it would slowly fall to the floor. After many trials and errors, a synergistic combination of geranyl crotonate and dihexyl fumarate esters was developed and given the name of Neutrolair D7. It suppressed malodors almost immediately. Following the establishment of good toxicological results and a suitable manufacturing process, it was placed on the market, along with a number of compatible “Neutrolair Scents.” Sadly, the air freshener marketers already had specific fragrances (and corresponding can labels). Some of their fragrances reacted chemically with the Neutrolair D7 and this eventually spelled the end of the program. About 1961, the industry was finally able to develop water-in-oil emulsions that could be pressurized with about 30% of A31 to A46 hydrocarbon propellants to produce acceptable air freshener sprays. As is well known, some esters are able to react chemically with water, forming equilibrium mixtures of ester-acid-alcohol-water. With Vintage Avon Bayberry-scented room spray. October 2015 Spray 27
Spray October2015
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