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Odorant (additive)
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] |
Odorant
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 Volatility (chemistry), 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 plant breeding, 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 Olfaction, 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 pe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methyl Acrylate
Methyl acrylate is an organic compound, more accurately the methyl ester of acrylic acid. It is a colourless liquid with a characteristic acrid odor. It is mainly produced to make acrylate fiber, which is used to weave synthetic carpets. It is also a reagent in the synthesis of various pharmaceutical intermediates. Owing to the tendency of methyl acrylate to polymerize, samples typically contain an inhibitor such as hydroquinone. Production The standard industrial reaction for producing methyl acrylate is esterification of acrylic acid with methanol under acid catalysis (sulfuric acid, p-toluenesulfonic acid or acidic ion exchangers.). The transesterification is facilitated because methanol and methyl acrylate form a low boiling azeotrope (boiling point 62–63 °C). The patent literature describes a one-pot route involving vapor-phase oxidation of propene or 2-propenal with oxygen in the presence of methanol. Other methods Methyl acrylate can be prepared by debrominatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gas Technologies
Gas is a state of matter that has neither a fixed volume nor a fixed shape and is a compressible fluid. A ''pure gas'' is made up of individual atoms (e.g. a noble gas like neon) or molecules of either a single type of atom ( elements such as oxygen) or from different atoms ( compounds such as carbon dioxide). A ''gas mixture'', such as air, contains a variety of pure gases. What distinguishes gases from liquids and solids is the vast separation of the individual gas particles. This separation can make some gases invisible to the human observer. The gaseous state of matter occurs between the liquid and plasma states, the latter of which provides the upper-temperature boundary for gases. Bounding the lower end of the temperature scale lie degenerative quantum gases which are gaining increasing attention. High-density atomic gases super-cooled to very low temperatures are classified by their statistical behavior as either Bose gases or Fermi gases. For a comprehensive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethanethiol
Ethanethiol, commonly known as ethyl mercaptan, is an organosulfur compound with the formula CH3CH2SH. It is a colorless liquid with a distinct odor. Abbreviated EtSH, it consists of an ethyl group (Et), CH3CH2, attached to a thiol group, SH. Its structure parallels that of ethanol, but with sulfur in place of oxygen. The odor of EtSH is infamous. Ethanethiol is more volatile than ethanol due to a diminished ability to engage in hydrogen bonding. Ethanethiol is toxic in high concentrations. It occurs naturally as a minor component of petroleum, and may be added to otherwise odorless gaseous products such as liquefied petroleum gas (LPG) to help warn of gas leaks. At these concentrations, ethanethiol is not harmful. Preparation Ethanethiol is prepared by the reaction of ethylene with hydrogen sulfide in the presence of various catalysts. It is also prepared commercially by the reaction of ethanol with hydrogen sulfide gas over an acidic solid catalyst, such as alumina. Historic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wintergreen Oil
Methyl salicylate (oil of wintergreen or wintergreen oil) is an organic compound with the formula C8H8O3. It is the methyl ester of salicylic acid. It is a colorless, viscous liquid with a sweet, fruity odor reminiscent of root beer (in which it is used as a flavoring), but often associatively called "minty", as it is an ingredient in mint candies. It is produced by many species of plants, particularly wintergreens. It is also produced synthetically, used as a fragrance and as a flavoring agent. Biosynthesis and occurrence Methyl salicylate was first isolated (from the plant ''Gaultheria procumbens'') in 1843 by the French chemist Auguste André Thomas Cahours (1813–1891), who identified it as an ester of salicylic acid and methanol. The biosynthesis of methyl salicylate arises via the hydroxylation of benzoic acid by a cytochrome P450 followed by reaction with a methyltransferase enzyme. Methyl salicylate as a plant metabolite Many plants produce methyl salicylate in sma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Society Of Mechanical Engineers
The American Society of Mechanical Engineers (ASME) is an American professional association that, in its own words, "promotes the art, science, and practice of multidisciplinary engineering and allied sciences around the globe" via "continuing education, training and professional development, codes and technical standard, standards, research, conferences and publications, government relations, and other forms of outreach." ASME is thus an engineering society, a standards organization, a research and development organization, an advocacy organization, a provider of training and education, and a nonprofit organization. Founded as an engineering society focused on mechanical engineering in North America, ASME is today multidisciplinary and global. ASME has over 85,000 members in more than 135 countries worldwide. ASME was founded in 1880 by Alexander Lyman Holley, Henry Rossiter Worthington, John Edison Sweet and Matthias N. Forney in response to numerous steam boiler pressure vessel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gas Pipeline Odourant Injection Facility
Gas is a state of matter that has neither a fixed volume nor a fixed shape and is a compressible fluid. A ''pure gas'' is made up of individual atoms (e.g. a noble gas like neon) or molecules of either a single type of atom ( elements such as oxygen) or from different atoms ( compounds such as carbon dioxide). A ''gas mixture'', such as air, contains a variety of pure gases. What distinguishes gases from liquids and solids is the vast separation of the individual gas particles. This separation can make some gases invisible to the human observer. The gaseous state of matter occurs between the liquid and plasma states, the latter of which provides the upper-temperature boundary for gases. Bounding the lower end of the temperature scale lie degenerative quantum gases which are gaining increasing attention. High-density atomic gases super-cooled to very low temperatures are classified by their statistical behavior as either Bose gases or Fermi gases. For a comprehensive listing of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kerosene Lantern
A kerosene lamp (also known as a paraffin lamp in some countries) is a type of lighting device that uses kerosene as a fuel. Kerosene lamps have a wick or mantle as light source, protected by a glass chimney or globe; lamps may be used on a table, or hand-held lanterns may be used for portable lighting. Like oil lamps, they are useful for lighting without electricity, such as in regions without rural electrification, in electrified areas during power outages, at campsites, and on boats. There are three types of kerosene lamp: flat-wick, central-draft (tubular round wick), and mantle lamp. Kerosene lanterns meant for portable use have a flat wick and are made in dead-flame, hot-blast, and cold-blast variants. Pressurized kerosene lamps use a gas mantle; these are known as Petromax, Tilley lamps, or Coleman lamps, among other manufacturers. They produce more light per unit of fuel than wick-type lamps, but are more complex and expensive in construction and more complex to opera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Candle Wick
A candle wick or lamp wick is usually made of braided cotton that holds the flame of a candle or oil lamp. A candle wick works by capillary action, conveying ("wicking") the fuel to the flame. When the liquid fuel, typically melted candle wax, reaches the flame it then vaporizes and combusts. In other words, the wick brings the liquified wax up into the flame to burn. The candle wick influences how the candle burns. Important characteristics of the wick include diameter, stiffness, fire-resistance, and tethering. Types Wicks are sometimes braided flat, so that as they burn they also curl back into the flame, thus making them self-consuming. The wick sizes determine the amount fuel brought into the flame. Prior to the introduction of these wicks specialty scissors were used to trim the excess wick without extinguishing the flame. Large diameter wicks typically result in a larger flame, a larger pool of melted wax, and the candle burning faster. In tealights, the wick is tet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alkylpyrazine
Alkylpyrazines are chemical compounds based on pyrazine with different substitution patterns. Some alkylpyrazines are naturally occurring highly Aroma compound, aromatic substances which often have a very low odor threshold and contribute to the taste and aroma of various foods including cocoa, baked goods, coffee and wines. Alkylpyrazines are also formed during the cooking of some foods via Maillard reactions. Examples File:2-Methylpyrazine.svg , 2-Methylpyrazine (found in roasted sesame) File:2,3-Dimethylpyrazine.svg , 2,3-Dimethylpyrazine (found in roasted sesame) File:2,5-Dimethylpyrazine.svg , 2,5-Dimethylpyrazine (asparagus, tea, crispbread, malt, shrimp, soy, squid, Swiss cheese, bread, roasted sesame) File:Tetramethylpyrazine v2.svg , 2,3,5,6-Tetramethylpyrazine (nattō, fermented cocoa beans) 2-Methylpyrazine 2-Methylpyrazine was the volatile odorant found at the highest concentration in roasted sesame seed oil. 2,3-Dimethylpyrazine 2,3-Dimethylpyrazine is a compo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
