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MCM-41
MCM-41 (Mobil Composition of Matter No. 41) is a mesoporous material with a hierarchical structure from a family of silicate and alumosilicate solids that were first developed by researchers at Mobil Oil Corporation and that can be used as catalysts or catalyst supports.Reichinger, M. (2007) ''Poröse Silikate mit hierarchischer Porenstruktur: Synthese von mikro-/mesoporösem MCM-41 und MCM-48 Materialien aus zeolithischen Baueinheiten des MFI-Gerüststrukturtyps'' Dissertation Ruhr-Universität Bochum (in German) Structure MCM-41 consists of a regular arrangement of cylindrical mesop ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MCM-41 Synthesis English 2014
MCM-41 (Mobil Composition of Matter No. 41) is a mesoporous material with a hierarchical structure from a family of silicate and alumosilicate solids that were first developed by researchers at Mobil Oil Corporation and that can be used as catalysts or catalyst supports.Reichinger, M. (2007) ''Poröse Silikate mit hierarchischer Porenstruktur: Synthese von mikro-/mesoporösem MCM-41 und MCM-48 Materialien aus zeolithischen Baueinheiten des MFI-Gerüststrukturtyps'' Dissertation Ruhr-Universität Bochum (in German) Structure MCM-41 consists of a regular arrangement of cylindrical mesop ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mobil Composition Of Matter
Mobil Composition of Matter (MCM) is the initial name given for a series of mesoporous materials that were first synthesized by Mobil's researchers in 1992. MCM-41 (Mobil Composition of Matter No. 41) and MCM-48 (Mobil Composition of Matter No. 48) are two of the most popular mesoporous molecular sieves that are keenly studied by researchers. The most striking fact about the MCM-41 and MCM-48 is that, although composed of amorphous silica wall, they possess long range ordered framework with uniform mesopores. These materials also possess large surface area, which can be up to more than 1000 m2g−1. Moreover, the pore diameter of these materials can be nicely controlled within mesoporous range between 1.5 and 20 nm by adjusting the synthesis conditions and/or by employing surfactants with different chain lengths in their preparation. MCM-41 and MCM-48 have been applied as catalysts for various chemical reactions, as a support for drug delivery system and as adsorbent in wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesoporous Carbon TEM
A mesoporous material (or super nanoporous ) is a nanoporous material containing pores with diameters between 2 and 50 nm, according to IUPAC nomenclature. For comparison, IUPAC defines microporous material as a material having pores smaller than 2 nm in diameter and macroporous material as a material having pores larger than 50 nm in diameter. Typical mesoporous materials include some kinds of silica and alumina that have similarly-sized mesopores. Mesoporous oxides of niobium, tantalum, titanium, zirconium, cerium and tin have also been reported. However, the flagship of mesoporous materials is mesoporous carbon, which has direct applications in energy storage devices. Mesoporous carbon has porosity within the mesopore range and this significantly increases the specific surface area. Another very common mesoporous material is activated carbon which is typically composed of a carbon framework with both mesoporosity and microporosity depending on the conditions un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesoporous
A mesoporous material (or super nanoporous ) is a nanoporous material containing pores with diameters between 2 and 50 nm, according to IUPAC nomenclature. For comparison, IUPAC defines microporous material as a material having pores smaller than 2 nm in diameter and macroporous material as a material having pores larger than 50 nm in diameter. Typical mesoporous materials include some kinds of silica and alumina that have similarly-sized mesopores. Mesoporous oxides of niobium, tantalum, titanium, zirconium, cerium and tin have also been reported. However, the flagship of mesoporous materials is mesoporous carbon, which has direct applications in energy storage devices. Mesoporous carbon has porosity within the mesopore range and this significantly increases the specific surface area. Another very common mesoporous material is activated carbon which is typically composed of a carbon framework with both mesoporosity and microporosity depending on the conditions un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cetrimonium Bromide
Cetrimonium bromide ( C16H33)N(CH3)3r; cetyltrimethylammonium bromide; hexadecyltrimethylammonium bromide; CTAB) is a quaternary ammonium surfactant. It is one of the components of the topical antiseptic cetrimide. The cetrimonium (hexadecyltrimethylammonium) cation is an effective antiseptic agent against bacteria and fungi. It is also one of the main components of some buffers for the extraction of DNA. It has been widely used in synthesis of gold nanoparticles (''e.g.'', spheres, rods, bipyramids), mesoporous silica nanoparticles (''e.g.'', MCM-41), and hair conditioning products. The closely related compounds cetrimonium chloride and cetrimonium stearate are also used as topical antiseptics and may be found in many household products such as shampoos and cosmetics. CTAB, due to its relatively high cost, is typically only used in select cosmetics. As with most surfactants, CTAB forms micelles in aqueous solutions. At 303 K (30 °C) it forms micelles with aggregation nu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zeolite
Zeolites are microporous, crystalline aluminosilicate materials commonly used as commercial adsorbents and catalysts. They mainly consist of silicon, aluminium, oxygen, and have the general formula ･y where is either a metal ion or H+. These positive ions can be exchanged for others in a contacting electrolyte solution. exchanged zeolites are particularly useful as solid acid catalysts. The term ''zeolite'' was originally coined in 1756 by Swedish mineralogist Axel Fredrik Cronstedt, who observed that rapidly heating a material, believed to have been stilbite, produced large amounts of steam from water that had been adsorbed by the material. Based on this, he called the material ''zeolite'', from the Greek , meaning "to boil" and , meaning "stone". Zeolites occur naturally but are also produced industrially on a large scale. , 253 unique zeolite frameworks have been identified, and over 40 naturally occurring zeolite frameworks are known. Every new zeolite structure that is ob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ExxonMobil
ExxonMobil Corporation (commonly shortened to Exxon) is an American multinational oil and gas corporation headquartered in Irving, Texas. It is the largest direct descendant of John D. Rockefeller's Standard Oil, and was formed on November 30, 1999, by the merger of Exxon and Mobil, both of which are used as retail brands, alongside Esso, for fueling stations and downstream products today. The company is vertically integrated across the entire oil and gas industry, and within it is also a chemicals division which produces plastic, synthetic rubber, and other chemical products. ExxonMobil is incorporated in New Jersey. ExxonMobil's earliest corporate ancestor was Vacuum Oil Company, though Standard Oil is its largest ancestor prior to its breakup. The entity today known as ExxonMobil grew out of the Standard Oil Company of New Jersey (or Jersey Standard for short), the corporate entity which effectively controlled all of Standard Oil prior to its breakup. Jersey Standard grew a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surfactant
Surfactants are chemical compounds that decrease the surface tension between two liquids, between a gas and a liquid, or interfacial tension between a liquid and a solid. Surfactants may act as detergents, wetting agents, emulsifiers, foaming agents, or dispersants. The word "surfactant" is a blend of ''surface-active agent'', coined . Agents that increase surface tension are "surface active" in the literal sense but are not called surfactants as their effect is opposite to the common meaning. A common example of surface tension increase is salting out: by adding an inorganic salt to an aqueous solution of a weakly polar substance, the substance will precipitate. The substance may itself be a surfactant – this is one of the reasons why many surfactants are ineffective in sea water. Composition and structure Surfactants are usually organic compounds that are amphiphilic, meaning each molecule contains both a hydrophilic "water-seeking" group (the ''head''), and a hydro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micelle
A micelle () or micella () (plural micelles or micellae, respectively) is an aggregate (or supramolecular assembly) of surfactant amphipathic lipid molecules dispersed in a liquid, forming a colloidal suspension (also known as associated colloidal system). A typical micelle in water forms an aggregate with the hydrophilic "head" regions in contact with surrounding solvent, sequestering the hydrophobic single-tail regions in the micelle centre. This phase is caused by the packing behavior of single-tail lipids in a bilayer. The difficulty filling all the volume of the interior of a bilayer, while accommodating the area per head group forced on the molecule by the hydration of the lipid head group, leads to the formation of the micelle. This type of micelle is known as a normal-phase micelle (oil-in-water micelle). Inverse micelles have the head groups at the centre with the tails extending out (water-in-oil micelle). Micelles are approximately spherical in shape. Other phases ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catalyst
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quickly, very small amounts of catalyst often suffice; mixing, surface area, and temperature are important factors in reaction rate. Catalysts generally react with one or more reactants to form intermediates that subsequently give the final reaction product, in the process of regenerating the catalyst. Catalysis may be classified as either homogeneous, whose components are dispersed in the same phase (usually gaseous or liquid) as the reactant, or heterogeneous, whose components are not in the same phase. Enzymes and other biocatalysts are often considered as a third category. Catalysis is ubiquitous in chemical industry of all kinds. Estimates are that 90% of all commercially produced chemical products involve catalysts at some s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cracking (chemistry)
In petrochemistry, petroleum geology and organic chemistry, cracking is the process whereby complex organic molecules such as kerogens or long-chain hydrocarbons are broken down into simpler molecules such as light hydrocarbons, by the breaking of carbon-carbon bonds in the precursors. The rate of cracking and the end products are strongly dependent on the temperature and presence of catalysts. Cracking is the breakdown of a large alkane into smaller, more useful alkenes. Simply put, hydrocarbon cracking is the process of breaking a long chain of hydrocarbons into short ones. This process requires high temperatures. More loosely, outside the field of petroleum chemistry, the term "cracking" is used to describe any type of splitting of molecules under the influence of heat, catalysts and solvents, such as in processes of destructive distillation or pyrolysis. Fluid catalytic cracking produces a high yield of petrol and LPG, while hydrocracking is a major source of jet fuel, die ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
