Odor stability

Characteristics (physical appearance/odor, stability, persistency, environmental fate)... 

Odor and color stability problems were also related to the alkyl chains used for SAI. These could be traced to the oxidation of unsaturated carbons, such as oleic acid (Ci8 fatty acid with a single double bond between carbon 9 and 10, i.e. bond position 9 counted from the carboxyl carbon), linoleic acid (Cis fatty acid with two double bonds at position 9 and 12), and linolenic acid (Cis fatty acid with three double bonds at position 9, 12, and 15). Natural coconut fatty acid contains about 6% oleic acid, about 3% linoleic acid, and less than 1% linolenic acid. Tallow fatty acid contains nearly 44% oleic and about 6% of other unsaturates [20]. Partial hydrogenation of the coconut fatty acid used in the manufacture of SCI served to eliminate linoleic and linolenic acids for improved odor stability, while not eliminating oleic acid, which is important for good lather. 

Blends of rice bran oil with soybean oil reduces the increase in total polar material (TPM) depending on the amount of rice bran oil in the blend (Table 19). Potato chips fried in rice bran oil show flavor and odor stability at elevated temperatures between that of peanut and cottonseed oUs (Table 20). 

Mineral oil undergoes oxidation when exposed to heat and light. Oxidation begins with the formation of peroxides, exhibiting an induction period . Under ordinary conditions, the induction period may take months or years. However, once a trace of peroxide is formed, further oxidation is autocatalytic and proceeds very rapidly. Oxidation results in the formation of aldehydes and organic acids, which impart taste and odor. Stabilizers may be added to retard oxidation butylated hydroxyanisole, butylated hydroxytoluene, and alpha tocopherol are the most commonly used antioxidants. 

U.S. 5,025,069 (1991) Deguchi et al. (Kao) Alkyl glucoside-based compositions terpene and isothiazolone derivatives Reduced irritation and damage to hair and skin color and odor stability... 

Isostearic acid is used in applications which require thermal stability in the case of a lubricant, odor stability for a cosmetic formulation, and oxidation stability for products with long shelf-life requirements. The branched structure of isostearic acid also enhances its dispersing power, and it is used in cosmetic and industrial applications for the stabilization of pigments and mineral particles in oils and solvents. 

Most fabric softeners have a pH of about 3.5, which limits to some extent the materials that can be used in the fragrances. For example, acetals carmot be used because they break down and cause malodor problems in addition, there is the likelihood of discoloration from Schiff bases (imines formed from aldehydes and methyl anthrarulate), certain natural extracts (e.g., oakmosses) and a few specialty chemicals. Testing of Iragrance materials in product bases is done under accelerated aging conditions (e.g., 40°C in plastic bottles) to check for odor stability and discoloration. 

Preventive and secondary antioxidants decompose hydroperoxides without intermediate formation of free radicals, preventing chain branching [20]. They are termed secondary because their best performance is achieved in the presence of primary antioxidants. They also contribute to melt flow and odor stabilization during processing. Aliphatic phos-ph(on)ites esters act only as secondary HD antioxidants while sterically hindered ortho-tcrt-alkylated aromatic compounds are capable of acting also as a primary radical chain breaking reaction. 

Nearly every chemical manufacturiag operation requites the use of separation processes to recover and purify the desired product. In most circumstances, the efficiency of the separation process has a significant impact on both the quality and the cost of the product (1). Liquid-phase adsorption has long been used for the removal of contaminants present at low concentrations in process streams. In most cases, the objective is to remove a specific feed component alternatively, the contaminants are not well defined, and the objective is the improvement of feed quality defined by color, taste, odor, and storage stability (2-5) (see Wastes, industrial Water, industrial watertreati nt). 

Many attempts have been made to reduce the ammoniacal and sulfurous odor of the standard thioglycolate formulations. As the cosmetics market is very sensitive to the presence of impurities, odor, and color, various treatments of purification have been claimed to improve the olfactory properties of thioglycolic acid and its salts, such as distillation (33), stabilization against the formation of H2S using active ingredients (34), extraction with solvents (35), active carbon (36), and chelate resin treatments (37). 

Calcium—zinc stabilizers are used in both plasticized PVC and rigid PVC for food contact where it is desired to minimize taste and odor characteristics. AppHcations include meat wrap, water botdes, and medical uses. 

Carbon tetrachloride [56-23-5] (tetrachloromethane), CCl, at ordinary temperature and pressure is a heavy, colorless Hquid with a characteristic nonirritant odor it is nonflammable. Carbon tetrachloride contains 92 wt % chlorine. When in contact with a flame or very hot surface, the vapor decomposes to give toxic products, such as phosgene. It is the most toxic of the chloromethanes and the most unstable upon thermal oxidation. The commercial product frequendy contains added stabilizers. Carbon tetrachloride is miscible with many common organic Hquids and is a powerhil solvent for asphalt, benzyl resin (polymerized benzyl chloride), bitumens, chlorinated mbber, ethylceUulose, fats, gums, rosin, and waxes. 

Trichloroethylene [79-01-6J, trichloroethene, CHCL=CCL2, commonly called "tri," is a colorless, sweet smelling (chloroformlike odor), volatile Hquid and a powerhil solvent for a large number of natural and synthetic substances. It is nonflammable under conditions of recommended use. In the absence of stabilizers, it is slowly decomposed (autoxidized) by air. The oxidation products are acidic and corrosive. Stabilizers are added to all commercial grades. Trichloroethylene is moderately toxic and has narcotic properties. 

Selected physical properties of chloroprene are Hsted in Table 1. When pure, the monomer is a colorless, mobile Hquid with slight odor, but the presence of small traces of dimer usually give a much stronger, distinctive odor similar to terpenes and inhibited monomer may be colored from the stabilizers used. Ir and Raman spectroscopy of chloroprene (4) have been used to estimate vibrational characteristics and rotational isomerization. 

Cyclohexanol [108-93-0] is a colorless, viscous liquid with a camphoraceous odor. It is used chiefly as a chemical iatermediate, a stabilizer, and a homogenizer for various soap detergent emulsions, and as a solvent for lacquers and varnishes. Cyclohexanol was first prepared by the treatment of 4-iodocyclohexanol with ziac dust ia glacial acetic acid, and later by the catalytic hydrogenation of phenol at elevated temperatures and pressures. 

Ethers, esters, amides and imidazolidines containing an epithio group are said to be effective in enhancing the antiwear and extreme pressure peiformance of lubricants. Other uses of thiiranes are as follows fuel gas odorant (2-methylthiirane), improvement of antistatic and wetting properties of fibers and films [poly(ethyleneglycol) ethers of 2-hydroxymethyl thiirane], inhibition of alkene metathesis (2-methylthiirane), stabilizers for poly(thiirane) (halogen adducts of thiiranes), enhancement of respiration of tobacco leaves (thiirane), tobacco additives to reduce nicotine and to reduce phenol levels in smoke [2-(methoxymethyl)thiirane], stabilizers for trichloroethylene and 1,1,1-trichloroethane (2-methylthiirane, 2-hydroxymethylthiirane) and stabilizers for organic compounds (0,0-dialkyldithiophosphate esters of 2-mercaptomethylthiirane). The product of the reaction of aniline with thiirane is reported to be useful in the flotation of zinc sulfide. 

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