|
Odorants
An aroma compound, also known as an odorant, aroma, fragrance, flavoring or flavor, is a chemical compound that has a smell or odor. For an individual chemical or class of chemical compounds to impart a smell or fragrance, it must be sufficiently volatile for transmission via the air to the olfactory system in the upper part of the nose. As examples, various fragrant fruits have diverse aroma compounds, particularly strawberries which are commercially cultivated to have appealing aromas, and contain several hundred aroma compounds. Generally, molecules meeting this specification have molecular weights of less than 310. Flavors affect both the sense of taste and smell, whereas fragrances affect only smell. Flavors tend to be naturally occurring, and the term ''fragrances'' may also apply to synthetic compounds, such as those used in cosmetics. Aroma compounds can naturally be found in various foods, such as fruits and their peels, wine, spices, floral scent, perfumes, frag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olfaction
The sense of smell, or olfaction, is the special sense through which smells (or odors) are perceived. The sense of smell has many functions, including detecting desirable foods, hazards, and pheromones, and plays a role in taste. In humans, it occurs when an odor binds to a receptor within the nasal cavity, transmitting a signal through the olfactory system. Glomeruli aggregate signals from these receptors and transmit them to the olfactory bulb, where the sensory input will start to interact with parts of the brain responsible for smell identification, memory, and emotion. There are many different things which can interfere with a normal sense of smell, including damage to the nose or smell receptors, anosmia, upper respiratory infections, traumatic brain injury, and neurodegenerative disease. History of study Early scientific study of the sense of smell includes the extensive doctoral dissertation of Eleanor Gamble, published in 1898, which compared olfactory to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Odor
An odor (American English) or odour ( Commonwealth English; see spelling differences) is a smell or a scent caused by one or more volatilized chemical compounds generally found in low concentrations that humans and many animals can perceive via their olfactory system. While ''smell'' can refer to pleasant and unpleasant odors, the terms ''scent'', ''aroma'', and ''fragrance'' are usually reserved for pleasant-smelling odors and are frequently used in the food and cosmetic industry to describe floral scents or to refer to perfumes. Odor physiology Sense of smell The perception of odors, or sense of smell, is mediated by the olfactory nerve. The olfactory receptor (OR) cells are neurons present in the olfactory epithelium, which is a small patch of tissue at the back of the nasal cavity. There are millions of olfactory receptor neurons that act as sensory signaling cells. Each neuron has cilia in direct contact with the air. Odorous molecules bind to receptor pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perfume Shelf 536pix
Perfume (, ) is a mixture of fragrance, fragrant essential oils or aroma compounds (fragrances), Fixative (perfumery), fixatives and solvents, usually in liquid form, used to give the human body, animals, food, objects, and living-spaces an agreeable scent. Perfumes can be defined as substances that emit and diffuse a pleasant and fragrant odor. They consist of artificial mixtures of aromatic chemicals and essential oils. The 1939 List of Nobel laureates, Nobel Laureate for Chemistry, Leopold Ružička stated in 1945 that "right from the earliest days of scientific chemistry up to the present time, perfumes have substantially contributed to the development of organic chemistry as regards methods, systematic classification, and theory." Ancient texts and archaeological excavations show the use of perfumes in some of the earliest human civilizations. Modern perfumery began in the late 19th century with the commercial synthesis of aroma compounds such as vanillin and coumarin, whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Odorizer
An odorizer is a device that adds an odorant to a gas. The most common type is one that adds a mercaptan liquid into natural gas distribution systems so that leaks can be readily detected. Other types have been used for carbon dioxide fire extinguishers. Natural gas odorizers Natural gas odorizers can vary from a simple wick in a container to computerized equipment, which controls the amount of odorant based on flow rate, tracks the amount of odorant in inventory, and alarms when odorant is not being injected into the gas stream. Odorants used for natural gas vary from country to country, depending on gas distribution regulations. Some odorants contain sulfur, which is oxidized to sulfur dioxide when the gas is burned. Sulfur-containing odorants include the following: * tert-Butylthiol (TBM) the main ingredient in many gas odorant blends * Tetrahydrothiophene (THT), used as an odorant for natural gas, usually in mixtures containing tert-butylthiol * 2-Propanethiol, commonl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propane
Propane () is a three-carbon chain alkane with the molecular formula . It is a gas at standard temperature and pressure, but becomes liquid when compressed for transportation and storage. A by-product of natural gas processing and petroleum refining, it is often a constituent of liquefied petroleum gas (LPG), which is commonly used as a fuel in domestic and industrial applications and in low-emissions public transportation; other constituents of LPG may include propene, propylene, butane, butene, butylene, butadiene, and isobutylene. Discovered in 1857 by the French chemist Marcellin Berthelot, it became commercially available in the US by 1911. Propane has lower volumetric energy density than gasoline or coal, but has higher gravimetric energy density than them and burns more cleanly. Propane gas has become a popular choice for barbecues and portable stoves because its low −42 °C boiling point makes it vaporise inside pressurised liquid containers (it exists in two pha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volatility (chemistry)
In chemistry, volatility is a material quality which describes how readily a substance vaporizes. At a given temperature and pressure, a substance with high volatility is more likely to exist as a vapour, while a substance with low volatility is more likely to be a liquid or solid. Volatility can also describe the tendency of a vapor to condense into a liquid or solid; less volatile substances will more readily condense from a vapor than highly volatile ones. Differences in volatility can be observed by comparing how fast substances within a group evaporate (or sublimate in the case of solids) when exposed to the atmosphere. A highly volatile substance such as rubbing alcohol (isopropyl alcohol) will quickly evaporate, while a substance with low volatility such as vegetable oil will remain condensed. In general, solids are much less volatile than liquids, but there are some exceptions. Solids that sublimate (change directly from solid to vapor) such as dry ice (solid carbon di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biochemical
Biochemistry, or biological chemistry, is the study of chemical processes within and relating to living organisms. A sub-discipline of both chemistry and biology, biochemistry may be divided into three fields: structural biology, enzymology, and metabolism. Over the last decades of the 20th century, biochemistry has become successful at explaining living processes through these three disciplines. Almost all areas of the life sciences are being uncovered and developed through biochemical methodology and research. Voet (2005), p. 3. Biochemistry focuses on understanding the chemical basis that allows biological molecules to give rise to the processes that occur within living cells and between cells, Karp (2009), p. 2. in turn relating greatly to the understanding of tissues and organs as well as organism structure and function. Miller (2012). p. 62. Biochemistry is closely related to molecular biology, the study of the molecular mechanisms of biological phenomena. Astbu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methyl Formate
Methyl formate, also called methyl methanoate, is the methyl ester of formic acid. The simplest example of a carboxylate ester, it is a colourless liquid with an ethereal odour, high vapor pressure, and low surface tension. The gas form is odourless and toxic, and used to be used in fridges. It is a precursor to many other compounds of commercial interest.Werner Reutemann and Heinz Kieczka "Formic Acid" in ''Ullmann's Encyclopedia of Industrial Chemistry'' 2002, Wiley-VCH, Weinheim. Production In the laboratory, methyl formate can be produced by the condensation reaction of methanol and formic acid, as follows: :HCOOH + CH3OH → HCOOCH3 + H2O Industrial methyl formate, however, is usually produced by the combination of methanol and carbon monoxide ( carbonylation) in the presence of a strong base, such as sodium methoxide: This process, practiced commercially by BASF among other companies gives 96% selectivity toward methyl formate. The catalyst for this process is s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geranyl Acetate Skeletal
Geraniol is a monoterpenoid and an alcohol. It is the primary component of citronella oil and is a primary component of rose oil and palmarosa oil. It is a colorless oil, although commercial samples can appear yellow. It has low solubility in water, but it is soluble in common organic solvents. Uses and occurrence In addition to being found in rose oil, palmarosa oil, and citronella oil, it also occurs in small quantities in geranium, lemon, and many other essential oils. With a rose-like scent, it is commonly used in perfumes and in scents such as peach, raspberry, grapefruit, red apple, plum, lime, orange, lemon, watermelon, pineapple, and blueberry. Geraniol is produced by the scent glands of honeybees to mark nectar-bearing flowers and locate the entrances to their hives. It is also commonly used as an insect repellent, especially for mosquitoes. The scent of geraniol is reminiscent of, but chemically unrelated to, 2-ethoxy-3,5-hexadiene, also known as geranium ta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rose
A rose is either a woody perennial plant, perennial flowering plant of the genus ''Rosa'' (), in the family Rosaceae (), or the flower it bears. There are over three hundred Rose species, species and Garden roses, tens of thousands of cultivars. They form a group of plants that can be erect shrubs, climbing, or trailing, with stems that are often armed with sharp Thorns, spines, and prickles, prickles. Their flowers vary in size and shape and are usually large and showy, in colours ranging from white through pinks, reds, oranges and yellows. Most species are native to Asia, with smaller numbers native to Europe, North America, and Northwest Africa. Species, cultivars and hybrid (biology), hybrids are all widely grown for their beauty and often are fragrant. Roses have acquired cultural significance in many societies. Rose plants range in size from compact, miniature roses to climbers that can reach seven meters in height. Different species hybridize easily, and this has been use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geranyl Acetate
Geranyl acetate is a terpenoid. It is a colorless liquid with a pleasant floral or fruity rose aroma. It is a colorless liquid but commercial samples can appear yellowish. Geranyl acetate is insoluble in water but soluble in organic solvents. Several hundred tons are produced annually. Occurrence and production Geranyl acetate is a constituent of many essential oils, including Ceylon citronella, palmarosa, lemon grass, petit grain, neroli, geranium, coriander, carrot, Camden woollybutt, and sassafras. It can be obtained by fractional distillation of the essential oils obtained from these sources, but more commonly it is prepared by the esterification of geraniol with acetic acid. Uses Geranyl acetate is used primarily as a component of perfumes for creams and soaps and as a flavoring ingredient. It is used particularly in rose, lavender and geranium formulations where a sweet fruity or citrus aroma is desired. It is designated by the U.S. Food and Drug Administration as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
