Odor Relative

Mineral spirits, a type of petroleum distillate popular for use in solvent-based house paints, consist mainly of aUphatic hydrocarbons with a trace of aromatics. This type of solvent finds use in oil- and alkyd-based house paints because of its good solvency with typical house paint binders and its relatively slow evaporation rate which imparts good bmshabiUty, open-time, and leveling. Other properties include lower odor, relatively lower cost, as well as safety and health hazard characteristics comparable to most other organic solvents. 

Observable Characteristics - Physical State (as shipped) Liquefied gas Color Colorless Odor Relatively odorless sweet, chloroform-like. 

Lemon oil is used in many food flavors. Because of its fresh odor, relatively large quantities are also employed in eau de cologne and other perfumery products. FCT 1974 (12) 725 [8008-56-8], [84929-31-7]. 

We have now reached a point at which we can define the three stages of odor familiarity First, we identify an odor relatively, then we know it absolutely, and finally we know it actively. In the first stage of familiarity we are able to identify an odor by our description of it, allowing our minds to search through our stored-up associations and classification. For example, given a sample of benzoin, our first impression may simply be "sweet." This in itself doesn t get us very far, since... 

Figure 1. Group mean total distance traveled per time bin for ten male (A) and nine female (B) meadow voles that previously had been housed in same sex groups. Voles had been exposed to predator odor (fox), extract of orange, butyric acid or a control condition (no odor) prior to monitoring of locomotor activity levels. Activity levels are significantly lower for 30 minutes following exposure to fox odor relative to all other odors in males.

Figure 3. Group mean number of movements per time bin during baseline activity recording and following exposure to predator odor (fox) for eight (A) male and seven female (B) meadow voles that previously had been housed in breeding pairs (1 female 1 male). The number of movements is significantly lower for 20 min in males, and the inital five minutes in females, following exposure to fox odor relative to the baseline condition.

Chemical compounds having odor and taste number in the thousands. In 1969 a description of the odor characteristics of more than three thousand chemical compounds used in the flavor and perfume industries were described (41). The Hst of volatile compounds found in food that may contribute to odor and taste is even larger (42), and the Hst of all possible flavor compounds, including those that have yet to be synthesized, is greater than a thousand. Many different compounds have the same flavor character or quaUty, differing perhaps in their relative intensity but indistinguishable in the type of flavor they ehcit. The exact number of different flavor quaUties is not known, but it appears to be much less than the total number of compounds with flavor. 

Metal Pan Assemblies. These units consist of tiles and panels formed from perforated aluminum or steel with pads of fiber glass or mineral wool inserted into the pans to provide the sound absorption. They are used primarily for ceilings in a similar manner to acoustical tiles and panels. The pads are sometimes sealed in plastic film to prevent absorption of moisture, dirt, and odors. The perforated metal is relatively sound transparent and functions as the finished ceiling and the support for the sound-absorbing material. The perforated metal by itself has no acoustical value. 

Naturally Derived Materials. The following are descriptions of some of the most important naturally derived materials in use. Importance in this context is defined in terms of the total value of the materials, which range from expensive, low volume materials that have great aesthetic value to relatively inexpensive and widely used products. Eor some of the naturals, it is indicated whether they can be distilled to provide individual chemicals for use as such or as intermediates. Materials produced in this way from a given natural source are usually not interchangeable with those from other naturals or synthetics. In some cases this may be due to optical isomerism, which can have a significant effect on odor, but usually it is due to trace impurities. 

Jasmine. Jasmine is one of the most precious florals used ia perfumery. The concrete of jasmine is produced by hydrocarbon extraction of flowers from Jasminum officinale (var. GrandijJorum). The concrete is then converted to absolute by alcohoHc extraction. It is produced ia many countries, the most important of which is India, followed by Egypt. Jasmine products are rather expensive and are produced ia relatively small amounts compared with other materials. However, jasmine is particularly important ia perfume creation for its great power and aesthetic quaUties. Eour of the principal odor contributors to jasmine are OT-jasmone [488-10-8] (14), methyl jasmonate [91905-974-] (15), benzyl acetate [140-11 ], and iudole [120-72-9] (16). 

Most aroma chemicals are relatively high boiling (80—160°C at 0.4 kPa = 3 mm Hg) Hquids and therefore are subject to purification by vacuum distillation. Because small amounts of decomposition may lead to unacceptable odor contamination, thermal stabiUty of products and by-products is an issue. Important advances have been made in distillation techniques and equipment to allow routine production of 5000 kg or larger batches of various products. In order to make optimal use of equipment and to standardize conditions for distillations and reactions, computer control has been instituted. This is particulady well suited to the multipurpose batch operations encountered in most aroma chemical plants. In some instances, on-line analytical capabihty is being developed to work in conjunction with computer controls. 

Plasticizer esters are relatively iaert, thermally stable Hquids with high flash points and low volatihty. Consequently they can be stored safely ia mild steel storage tanks or dmms for extended periods of time. Exposure to high temperatures for extended periods, as encountered ia dmms ia hot climates, is not recommended since it may lead to a deterioration in product quaUty with respect to color, odor, and electrical resistance. 

The three isomeric diallyl phthalates are colorless Hquids of mild, odor, low volatiUty, and relatively slow polymerisation ia the early stages. At ca 25% conversion, the viscous Hquid undergoes gelation and polymerisation accelerates however, the last monomer disappears at a slow rate. 

With the exception of neopentyl alcohol (mp 53°C), the amyl alcohols are clear, colorless Hquids under atmospheric conditions, with characteristic, slightly pungent and penetrating odors. They have relatively higher boiling poiats than ketonic or hydrocarbon counterparts and are considered iatermediate boiling solvents for coating systems (Table 1) (1—16). 

Styrene is mildly toxic, flammable, and can be made to polymerize violently under certain conditions. However, handled according to proper procedures, it is a relatively safe organic chemical. Styrene vapor has an odor threshold of 50—150 ppm (72,73). 

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. 

The unusual physical complaints and findings in workers overexposed to teUurium include somnolence, anorexia, nausea, perspiration, a metallic taste in the mouth and garlic-like odor on the breath (48). The unpleasant odor, attributed to the formation of dimethyl teUuride, has not been associated with any adverse health symptoms. Tellurium compounds and metaboUc products have been identified in exhaled breath, sweat, urine, and feces. Elimination is relatively slow and continuous exposure may result in some accumulation. No definite pathological effects have been observed beyond the physical complaints outlined. Unlike selenium, teUurium has not been proved to be an essential biological trace element. 

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