Molecules perfume

Pyrolytic Decomposition. The pyrolytic decomposition at 350—460°C of castor oil or the methyl ester of ricinoleic acid spHts the ricinoleate molecule at the hydroxyl group forming heptaldehyde and undecylenic acids. Heptaldehyde, used in the manufacture of synthetic flavors and fragrances (see Elavors and spices Perfumes) may also be converted to heptanoic acid by various oxidation techniques and to heptyl alcohol by catalytic hydrogenation. When heptaldehyde reacts with benzaldehyde, amyl cinnamic aldehyde is produced (see Cinnamic acid, cinnamaldehyde, and cinnamyl... 

Methyl vanillin is used in flavorings, fragrances, pharmaceuticals, and perfumes. It is closely related to ethyl vanillin, a slightly larger molecule. 

The surfactant ammonium xylenesulfonate is used as both a thickener and a hydrotrope, a compound that makes it easier for water to dissolve other molecules. It helps keep other ingredients in solution, including some of the odd substances that are added for marketing effect, such as perfumes. Glycerol stearate is another emulsifier used for this purpose. 

The dense fluid that exists above the critical temperature and pressure of a substance is called a supercritical fluid. It may be so dense that, although it is formally a gas, it is as dense as a liquid phase and can act as a solvent for liquids and solids. Supercritical carbon dioxide, for instance, can dissolve organic compounds. It is used to remove caffeine from coffee beans, to separate drugs from biological fluids for later analysis, and to extract perfumes from flowers and phytochemicals from herbs. The use of supercritical carbon dioxide avoids contamination with potentially harmful solvents and allows rapid extraction on account of the high mobility of the molecules through the fluid. Supercritical hydrocarbons are used to dissolve coal and separate it from ash, and they have been proposed for extracting oil from oil-rich tar sands. 

Plants produce a vast array of terpenes, alkenes built in multiples of five carbon atoms. Many terpenes have characteristic fragrances. For example, the fresh odor of a pine forest is due to pinene, a ten-carbon molecule with a ring structure and one double bond. The fragrances of terpenes make them important in the flavor and fragrance industry. Limonene, another ten-carbon molecule with a ring and two double bonds, is the principal component of lemon oil. Geraniol, a chainlike molecule with two double bonds, is one of the molecules that is responsible for the fragrance of roses and is used in many perfumes. Many other terpenes have important medicinal properties. 

Abandoning the hunt for linear, fiber-forming molecules, he turned to polymer ring compounds. Before Carothers, cyclic compounds were so difficult to make that no one studied them, but his group had tasted scientific blood and was happily publishing papers. When they discovered a series of ring compounds that produce synthetic scents, Du Pont sold the compounds to the perfume industry. The cyclic compounds were the last of Carothers fundamental scientific studies. After completing them, he drifted for a while, unclear as to what direction his research should take. 

Frankincense, also known as olibanum, is obtained from trees belonging to the genus Boswellia (Burseraceae family). It is one of the best-known ancient plant resins. The ancient Egyptians were the first to use it as incense in embalming practices and in the preparation of medicines, cosmetics and perfumes, and today it is still used therapeutically. It contains pentacyclic triterpenoids belonging to oleanane, ursane or lupane type molecules and in particular of a- and p-boswellic acids, and their O-acetates [104 111], 11 -Oxo-p-boswellic acid and its acetyl derivative, identified in several Boswellia species, are also diagnostic for frankincense [112]. 

In this equation x, is the liquid perfume concentration, Mt the molecular weight, R the ideal gas constant, and T the absolute temperature. Equation 2 relates the liquid perfume composition, x, with the human sensory reaction of the evaporated perfume. A key factor of Equation 2 is the activity coefficient, y, because it represents the affinity of a molecule to its neighboring medium. High value of y means an increased inclination for a given substance to be released from the mixture and low value of y means a low concentration in the headspace. This means that the OV values of a particular component can change if it is diluted in different solvents or mixed with different fragrance components. 

Like most stories, that of chemistry has another side, less often noted or remarked but a whole lot more pleasant. The world of chemistry is the world of molecules. It is a complex, critical, and fascinating world. Molecules and their constituents (atoms) make up all matter. Specific molecules affect every aspect of our lives every day, frequently for better but occasionally for worse. The simple fact is that almost everything that we use in daily life has been chemically modified in some way consider plastics, alloys, detergents and soaps, paper, perfumes and colognes, and our drinking water. It is difficult to imagine life without the products of modem chemistry. 

The sense of smell in humans is not limited to detection of those volatile molecules inhaled through the nose, termed orthonasal olfaction. Molecules released at the back of the mouth, particularly in the chewing of food, can make their way up through the nasopharynx to the olfactory epithelium, termed retronasal olfaction. This system is activated when air is exhaled. Orthonasal olfaction is used to detect the scent of flowers and perfumes, food aromas, the presence of skunks, and the like. Retronasal olfaction detects the volatile molecules released from food. It is retronasal olfaction that makes a major olfactory contribution to the taste of food. And it is retronasal olfaction that helped to elicit Proust s profound reaction to a madeleine dipped in tea. 

In order to smell something, the molecules of that something must evaporate and reach your nose. If the new perfume doesn t evaporate, it will not have an odor. 

When a bottle of perfume is opened, odorous molecules mix with air and slowly diffuse throughout the entire room. Is AG for the diffusion process positive, negative, or zero What about AH and AS for the diffusion ... 

The constant motion and high velocities of gas particles lead to some important practical consequences. One such consequence is that gases mix rapidly when they come in contact. Take the stopper off a bottle of perfume, for instance, and the odor will spread rapidly through the room as perfume molecules mix with the molecules in the air. This mixing of different gases by random molecular motion with frequent collisions is called diffusion. A similar process in which gas molecules escape without collisions through a tiny hole into a vacuum is called effusion (Figure 9.13). 

But what are we to call the retrosynthetic transformation of 11 into 10 It isn t a disconnection rather an extra carbon atom has been added. So we call this operation a reconnection joining the target molecule back up to something to reveal the precursor. So, consider the synthesis of the m-enone 21, a structure found in insect pheromones, perfumes and flavourings. A Wittig... 

A. Graham s law describes the rate of diffusion (or effusion) of a gas, in this instance, the rate of diffusion of molecules in perfume vapor. 

The decarboxylation of diacyl peroxides was also applied in the synthesis of cydopentadecanone, a compound with a musky odor of interest in the perfume industry (Scheme 2.31) [62].The photolysis of tetraacyl diperoxides 119 led to the extrusion of four molecules of C02 to give 121 in 73% yield. When decarboxylation occurred thermally, the product was obtained in only 41% yield. While the diacyl peroxide containing a keto group (106) was shown to give side products, the ketal-protected diperoxide 120 decarboxylated efficiently to give 122 in 65% yield. 

Vapor pressure is caused by the evaporation of molecules at the surface of a liquid. These escaping molecules exert an upward pressure as they leave the liquid (Figure 7.2). For example, gasoline has a greater vapor pressure than syrup because molecules of gasoline evaporate more readily than molecules of syrup. Perfume and alcohol have vapor pressures that are greater than the vapor pressure of water. 

More recently the great advance that has been made in chemical analysis and the synthesis of complex organic molecules has made possible a much closer approximation to the actual composition and odor of natural flower products. Even so, few of these reconstructed naturals, invaluable though they are, can provide a full replacement for the genuine product. They may best be thought of as specialized bases resulting from a collaboration between the chemist and creative perfumer. 

The nature of the perfume material. Molecules with a large molecular diameter diffuse far less rea< than smaller ones, and polar materials (with relatively high water solubility) less readily than nonpoh ones (compare Table 13.8). 

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