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Steam Distillation
Steam distillation is a separation process that consists in distilling water together with other volatile and non-volatile components. The steam from the boiling water carries the vapor of the volatiles to a condenser; both are cooled and return to the liquid or solid state, while the non-volatile residues remain behind in the boiling container. If, as is usually the case, the volatiles are not miscible with water, they will spontaneously form a distinct phase after condensation, allowing them to be separated by decantation or with a separatory funnel. Steam distillation can be used when the boiling point of the substance to be extracted is higher than that of water, and the starting material cannot be heated to that temperature because of decomposition or other unwanted reactions. It may also be useful when the amount of the desired substance is small compared to that of the non-volatile residues. It is often used to separate volatile essential oils from plant mat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steam Distilation
Steam is a substance containing water in the gas phase, and sometimes also an aerosol of liquid water droplets, or air. This may occur due to evaporation or due to boiling, where heat is applied until water reaches the enthalpy of vaporization. Steam that is saturated or superheated is invisible; however, "steam" often refers to wet steam, the visible mist or aerosol of water droplets formed as water vapor condenses. Water increases in volume by 1,700 times at standard temperature and pressure; this change in volume can be converted into mechanical work by steam engines such as reciprocating piston type engines and steam turbines, which are a sub-group of steam engines. Piston type steam engines played a central role in the Industrial Revolution and modern steam turbines are used to generate more than 80% of the world's electricity. If liquid water comes in contact with a very hot surface or depressurizes quickly below its vapor pressure, it can create a steam explosion. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boiler
A boiler is a closed vessel in which fluid (generally water) is heated. The fluid does not necessarily boil. The heated or vaporized fluid exits the boiler for use in various processes or heating applications, including water heating, central heating, boiler-based power generation, cooking, and sanitation. Heat sources In a fossil fuel power plant using a steam cycle for power generation, the primary heat source will be combustion of coal, oil, or natural gas. In some cases byproduct fuel such as the carbon monoxide rich offgasses of a coke battery can be burned to heat a boiler; biofuels such as bagasse, where economically available, can also be used. In a nuclear power plant, boilers called steam generators are heated by the heat produced by nuclear fission. Where a large volume of hot gas is available from some process, a heat recovery steam generator or recovery boiler can use the heat to produce steam, with little or no extra fuel consumed; such a configuration is c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perfumes
Perfume (, ; french: parfum) is a mixture of fragrant essential oils or aroma compounds (fragrances), fixatives and solvents, usually in liquid form, used to give the human body, animals, food, objects, and living-spaces an agreeable scent. The 1939 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 or coumarin, which allowed for the composition of perfumes with smells previously unattainable solely from natural aromatics. History The word ''perfume'' derives from the Latin ''perfumare'', meaning "to smoke through". P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steam Water Distiller
Steam is a substance containing water in the gas phase, and sometimes also an aerosol of liquid water droplets, or air. This may occur due to evaporation or due to boiling, where heat is applied until water reaches the enthalpy of vaporization. Steam that is saturated or superheated is invisible; however, "steam" often refers to wet steam, the visible mist or aerosol of water droplets formed as water vapor condenses. Water increases in volume by 1,700 times at standard temperature and pressure; this change in volume can be converted into mechanical work by steam engines such as reciprocating piston type engines and steam turbines, which are a sub-group of steam engines. Piston type steam engines played a central role in the Industrial Revolution and modern steam turbines are used to generate more than 80% of the world's electricity. If liquid water comes in contact with a very hot surface or depressurizes quickly below its vapor pressure, it can create a steam explosion. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Celsius
The degree Celsius is the unit of temperature on the Celsius scale (originally known as the centigrade scale outside Sweden), one of two temperature scales used in the International System of Units (SI), the other being the Kelvin scale. The degree Celsius (symbol: °C) can refer to a specific temperature on the Celsius scale or a unit to indicate a difference or range between two temperatures. It is named after the Swedish astronomer Anders Celsius (1701–1744), who developed a similar temperature scale in 1742. Before being renamed in 1948 to honour Anders Celsius, the unit was called ''centigrade'', from the Latin ''centum'', which means 100, and ''gradus'', which means steps. Most major countries use this scale; the other major scale, Fahrenheit, is still used in the United States, some island territories, and Liberia. The Kelvin scale is of use in the sciences, with representing absolute zero. Since 1743 the Celsius scale has been based on 0 °C for the freezing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bromobenzene
Bromobenzene is an aryl halide, C6H5Br. It is a colourless liquid although older samples can appear yellow. It is a reagent in organic synthesis. Synthesis and reactions Bromobenzene is prepared by the action of bromine on benzene in the presence of Lewis acid catalysts such as aluminium chloride or ferric bromide. Bromobenzene is used to introduce a phenyl group into other compounds. One method involves its conversion to the Grignard reagent, phenylmagnesium bromide. This reagent can be used, e.g. in the reaction with carbon dioxide to prepare benzoic acid. Other methods involve palladium-catalyzed coupling reactions, such as the Suzuki reaction. Bromobenzene is used as a precursor in the manufacture of phencyclidine. Toxicity Animal tests indicate low toxicity. Little is known about chronic effects. For liver toxicity, the 3,4-epoxide are proposed intermediates. See also *Fluorobenzene *Chlorobenzene *Iodobenzene Iodobenzene is an organoiodine compound consisting of a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Azeotrope
An azeotrope () or a constant heating point mixture is a mixture of two or more liquids whose proportions cannot be altered or changed by simple distillation.Moore, Walter J. ''Physical Chemistry'', 3rd e Prentice-Hall 1962, pp. 140–142 This happens when an azeotrope is boiled, the vapour has the same proportions of constituents as the unboiled mixture. Because their composition is unchanged by distillation, azeotropes are also called (especially in older texts) ''constant boiling point mixtures''. Some azeotropic mixtures of pairs of compounds are known, and many azeotropes of three or more compounds are also known. In such a case it is not possible to separate the components by fractional distillation and azeotropic distillation is usually used instead. There are two types of azeotropes: minimum boiling azeotrope and maximum boiling azeotrope. A solution that shows greater positive deviation from Raoult's law forms a minimum boiling azeotrope at a specific composition. For ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Partial Pressure
In a mixture of gases, each constituent gas has a partial pressure which is the notional pressure of that constituent gas as if it alone occupied the entire volume of the original mixture at the same temperature. The total pressure of an ideal gas mixture is the sum of the partial pressures of the gases in the mixture ( Dalton's Law). The partial pressure of a gas is a measure of thermodynamic activity of the gas's molecules. Gases dissolve, diffuse, and react according to their partial pressures but not according to their concentrations in gas mixtures or liquids. This general property of gases is also true in chemical reactions of gases in biology. For example, the necessary amount of oxygen for human respiration, and the amount that is toxic, is set by the partial pressure of oxygen alone. This is true across a very wide range of different concentrations of oxygen present in various inhaled breathing gases or dissolved in blood; consequently, mixture ratios, like that of breat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vapor Pressure
Vapor pressure (or vapour pressure in English-speaking countries other than the US; see spelling differences) or equilibrium vapor pressure is defined as the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases (solid or liquid) at a given temperature in a closed system. The equilibrium vapor pressure is an indication of a liquid's evaporation rate. It relates to the tendency of particles to escape from the liquid (or a solid). A substance with a high vapor pressure at normal temperatures is often referred to as '' volatile''. The pressure exhibited by vapor present above a liquid surface is known as vapor pressure. As the temperature of a liquid increases, the kinetic energy of its molecules also increases. As the kinetic energy of the molecules increases, the number of molecules transitioning into a vapor also increases, thereby increasing the vapor pressure. The vapor pressure of any substance increases non-linearly with temperature accord ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rose Water
Rose water ( fa, گلاب) is a flavoured water made by steeping rose petals in water. It is the hydrosol portion of the distillate of rose petals, a by-product of the production of rose oil for use in perfume. Rose water is also used to flavour food, as a component in some cosmetic and medical preparations, and for religious purposes throughout Asia and Europe. Rose syrup (not to be confused with rose hip syrup) is a syrup made from rose water, with sugar added. Gulkand in South Asia is a syrupy mashed rose mixture. Central Iran is home to the annual Golabgiri festival each spring. Thousands of tourists visit the area to celebrate the rose harvest for the production of ''golâb'' (). Iran accounts for 90% of world production of rose water. History Since ancient times, roses have been used medicinally, nutritionally, and as a source of perfume. Rose perfumes are made from rose oil, also called '' attar of roses'', which is a mixture of volatile essential oils obtained ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Al-Dimashqi (geographer)
Sheikh Shams al-Din al-Ansari al-Dimashqi or simply al-Dimashqi ( ar, شمس الدين الأنصاري الدمشقي) (1256–1327) was a medieval Arab geographer, completing his main work in 1300. Born in Damascus—as his name "Dimashqi" implies—he mostly wrote of his native land, the Greater Syria (''Bilad ash-Sham''), upon the complete withdrawal of the Crusaders. He became a contemporary of the Mamluk sultan Baibars, the general who led the Muslims in war against the Crusaders. His work is of value in connection with the Crusader Chronicles. He died while in Safad, in 1327.le Strange, 1890p.10 Al-Dimashqi (1325) gives detailed accounts of islands in Maritime Southeast Asia, its inhabitants, flora, fauna and customs. He mentions "the country of Champa...is inhabited by Muslims and idolaters. Islam arrived there during the time of Caliph Uthman...and Ali, many Muslims who were expelled by the Umayyads and by Al-Hajjaj, fled there, and since then a majority of the Cham ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Essential Oils
An essential oil is a concentrated hydrophobic liquid containing volatile (easily evaporated at normal temperatures) chemical compounds from plants. Essential oils are also known as volatile oils, ethereal oils, aetheroleum, or simply as the oil of the plant from which they were extracted, such as oil of clove. An essential oil is essential in the sense that it contains the essence of the plant's fragrance—the characteristic fragrance of the plant from which it is derived. The term "essential" used here does ''not'' mean indispensable or usable by the human body, as with the terms essential amino acid or essential fatty acid, which are so called because they are nutritionally required by a living organism. Essential oils are generally extracted by distillation, often by using steam. Other processes include expression, solvent extraction, '' sfumatura'', absolute oil extraction, resin tapping, wax embedding, and cold pressing. They are used in perfumes, cosmetics, soap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
