Odor fatty acid

FLEC measurements of a complaint case of malodorous linoleum showed that wetting of the material increased the emission of, e.g., odorous fatty acids. (Wolkoff et al., 1995). The impact of humidity has also been investigated for other building products (Wolkoff, 1996b). In this article, the impact of temperature, nitrogen instead of air and air velocity in the FLEC have also been investigated for VOCs with low human odor thresholds. 

Waxes, sueh as camauba and ->candelilla, which impart high gloss, especially to wood floors - turpentine is frequently used as the solvent of choice, especially because of its clean, typical p.-odor - fatty acids are reacted with basic nigrosine dyes in dispersions for shoe p. The in situ produced salts of - fatty acids with ammonia and morpholine are emulsifiers for p. offered in emulsion form. Other emulsifiers, such as ->sorbitan esters of fatty acids are, applied frequently. Small amounts of nonionic or anionic - surfactants are used in some p. as leveling agent. 

DeodoriZation. Removal of volatile odorous material and residual fatty acids is the final step ki ok processkig prior to packagkig or filling for bulk shipment (28). The ok is heated to 230—260°C under vacuum. Steam is passed through the ok to assist ki carrying over the volatile material. 

Aldehydes, enals, dienals, ketones, and hydrocarbons, which are responsible for disagreeable odors, generally bok at lower temperatures than fatty acids. Analysis showkig a free fatty acid concentration of less than 0.05% is an kidication that deodorization is sufficientiy complete. Some of the dienals have very low odor thresholds and sensory evaluation of the finished ok is a judicious quaHty assurance step. 

Deodorization can be carried out ki batch, continuous, or semicontkiuous systems. Figure 4 shows a typical design for a semicontkiuous deodorizer. The heated ok is passed through a series of trays under vacuum. Steam is passed through the ok through a steam sparge ki the bottom of the tray. Volatiles are carried through the headspace and condensed. In addition to fatty acids and compounds responsible for odor, some tocopherols and sterols are also distilled kito the condensate. The amount of tocopherols distilled depends on deodorization temperature and vacuum. 

Substances other than enzymes can be immobilized. Examples include the fixing of heparin on polytetrafluoroethylene with the aid of PEI (424), the controUed release of pesticides which are bound to PEI (425), and the inhibition of herbicide suspensions by addition of PEI (426). The uptake of anionic dyes by fabric or paper is improved if the paper is first catonized with PEI (427). In addition, PEI is able to absorb odorizing substances such as fatty acids and aldehydes. Because of its high molecular weight, PEI can be used in cosmetics and body care products, as weU as in industrial elimination of odors, such as the improvement of ambient air quaHty in sewage treatment plants (428). 

Commercial cmde lecithin is a brown to light yeUow fatty substance with a Hquid to plastic consistency. Its density is 0.97 g/mL (Uquid) and 0.5 g/mL (granule). The color is dependent on its origin, process conditions, and whether it is unbleached, bleached, or filtered. Its consistency is deterrnined chiefly by its oil, free fatty acid, and moisture content. Properly refined lecithin has practically no odor and has a bland taste. It is soluble in aflphatic and aromatic hydrocarbons, including the halogenated hydrocarbons however, it is only partially soluble in aflphatic alcohols (Table 5). Pure phosphatidylcholine is soluble in ethanol. 

Tall oil rosin is a by-product of paper manufacturing. Raw wood chips are digested under heat and pressure with a mixture of sodium hydroxide and sodium sulfide. Soluble sodium salts of lignin, rosin, and fatty acids are formed, which are removed from the wood pulp as a dark solution. The soaps of the rosin and fatty acids float to the top of the mixture, where they are skimmed off and treated with sulfuric acid to free the rosin and fatty acids. This mixture, known as cmde tall oil (CTO), is refined further to remove color and odor bodies fractional distillation separates the tall oil rosin acids from the fatty acids (see Tall oil). 

The quaHty, ie, level of impurities, of the fats and oils used in the manufacture of soap is important in the production of commercial products. Fats and oils are isolated from various animal and vegetable sources and contain different intrinsic impurities. These impurities may include hydrolysis products of the triglyceride, eg, fatty acid and mono/diglycerides proteinaceous materials and particulate dirt, eg, bone meal and various vitamins, pigments, phosphatides, and sterols, ie, cholesterol and tocopherol as weU as less descript odor and color bodies. These impurities affect the physical properties such as odor and color of the fats and oils and can cause additional degradation of the fats and oils upon storage. For commercial soaps, it is desirable to keep these impurities at the absolute minimum for both storage stabiHty and finished product quaHty considerations. 

The fatty acids obtained from the process can be used directly or further manipulated for improved or modified performance and stabiUty. Hardening is an operation in which some fraction of the unsaturated bonds present in the fatty acids are eliminated through hydrogenation or the addition of H2 across a carbon—carbon double bond. This process was initially intended to improve the odor and color stabiUty of fatty acids through elimination of the polyunsaturated species. However, with the growth in the use of specialty fatty acids, hydrogenation is a commercially important process to modify the physical properties of the fatty acids. 

The physical properties of the fatty acid ethoxylates depend on the nature of the fatty acid and even more on ethylene oxide content. As the latter increases, consistencies of the products change from free-flowing Hquids to slurries to firm waxes (qv). At the same time, odor, which is characteristic of the fatty acid, decreases in intensity. Odor and color stabiUty are important commercial properties, particularly in textile appHcations. Oleic acid esters, though possessing good functional properties, cannot be used because they tend to yellow on exposure to heat and air. 

Distillation By-Products. Of the CTO distiHation by-products, ie, pitch, heads, and DistiHed TaH Oil (DTO), only the last, a unique mixture of rosin and fatty acids, has significant commercial value. Pitch and heads are used as fuel the former has a fuel value of 41,800 kj/kg. TaH oil heads have outstanding solvent properties, but also have a bad odor, which is hard to remove. They contain a relatively high fraction of palmitic acid which can be recovered by crystallization. 

Attempts have also been made to reduce the odor associated with the peracid in the home laundry. Use of a precursor that generates the peracid of a fatty acid can result in an objectionable odor in the wash bath (106). This odor is exacerbated by the higher piC of the peracid versus its parent acid resulting in a greater proportion of the peracid in the unionized and therefore less water-soluble form. To mitigate this circumstance, functionalization of the fatty tail typically alpha to the carbonyl has been utilized (112). The modifications include alpha-chloro and alpha-methoxy substituents on the parent acid portion of the precursor ester. 

Distillation. Most fatty acids are distilled to produce high quaHty products having exceUent color and a low level of impurities. Distillation removes odor bodies and low boiling unsaponifiable material in a light ends or heads fraction, and higher boiling material such as polymerized material, triglycerides, color bodies, and heavy decomposition products are removed as a bottoms or pitch fraction. The middle fractions sometimes can be used as is, or they can be fractionated (separated) into relatively pure materials such as lauric, myristic, palmitic, and stearic acids. 

Paint and varnish manufacturing Resin manufacturing closed reaction vessel Varnish cooldng-open or closed vessels Solvent thinning Acrolein, other aldehydes and fatty acids (odors), phthalic anhydride (sublimed) Ketones, fatty acids, formic acids, acetic acid, glycerine, acrolein, other aldehydes, phenols and terpenes from tall oils, hydrogen sulfide, alkyl sulfide, butyl mercaptan, and thiofen (odors) Olefins, branched-chain aromatics and ketones (odors), solvents Exhaust systems with scrubbers and fume burners Exhaust system with scrubbers and fume burners close-fitting hoods required for open kettles Exhaust system with fume burners... 

Transesterification of fat triglycerides is the predominant method for manufacture of mixed fatty acid methyl esters, and direct esterification of fatty acids (FA) is practiced if very selective cuts of product, in general as an intermediate detergent range alcohol, are desired. Methyl cocoate is a mobile, oily liquid above 25 °C with a yellow tint and a characteristic fatty pungent odor. FAME sulfonation to FAMES is technically possible but been rarely applied up to now (1990) (Table 13). 

Odor and color instability was traced to the choice of SAI. The original Monsavon composition used an SAI blend made from 80% coconut fatty acid and 20% tallow fatty acid. A characteristic alkyl chain length distribution for the resulting SAI is shown in Table 9.4-1. 

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. 

Pentaerythritol Ester As with glycerol esters, the esters are produced by esterification of pentaerythritol with the desired fatty acids. For example, under defined reaction conditions and use of stearic acid in defined concentration, pentaerythritol distearate has been recently developed as an off-white wax with very weak odor (Cutina PES). This type of product is offered as co-emulsifier and consistency factor for cosmetic products with high sensorial elegance and can be applied in various formulations (Fig. 4.17). 

Oleic acid is a normal constituent of animal fat, including ant fat. When an ant dies and its body begins to decompose, its fat breaks down and releases odoriferous fatty acids. If the ant dies within its nest, the odor of oleic acid serves as a posthumous chemical signal to its surviving nestmates. On detecting oleic acid, an ant worker s response is to pick up the source (the dead ant) and carry it a short distance toward the nest entrance before setting it down. Eventually, after several workers have moved it, the carcass reaches the entrance, where it is finally ejected from the nest. 

Many hunters react to their prey s overall scent or some of its components, perhaps the smell of fur or some less complex odor. One of the world s most injurious insects, the African malaria mosquito (Anopheles gambiae), prefers humans to other sources of a blood meal. Oddly, whenever possible the mosquitoes bite people on their feet. This predilection reflects their strong attraction to the mixture of fatty acids that we associate with smelly feet. Humans may find the odor offensive, but these mosquitoes know it as a fragrant guide to blood. The same fatty acids also draw them to another odor that offends some people, the smell of Limburger cheese. 

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