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Vacuum Oven
In chemistry, a vacuum oven is an oven that can also apply a vacuum to its contents. Such devices are useful for removing solvent or dehydrating samples. They are equivalent to Abderhalden's drying pistol in some ways, but vacuum ovens typically can accommodate large samples. A characteristic operation for a vacuum oven is the activation or regeneration of molecular sieves. Vacuum furnaces are related devices that operate at much higher temperatures and much lower pressures. The acetylacetonate complex Mn(acac)2 is obtained by vacuum drying the yellow dihydrate Mn(acac)2(H2O)2.{{cite book , doi=10.1002/9780470132371.ch51 , chapter=Manganese(II) Acetylacetonate , date=1960 , last1=Charles , first1=Robert G. , title=Inorganic Syntheses , volume=6 , pages=164–166 , isbn=978-0-470-13165-7 References [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular Sieve
A molecular sieve is a material with pores of uniform size comparable to that of individual molecules, linking the interior of the solid to its exterior. These materials embody the molecular sieve effect, in which molecules larger than the pores are preferentially sieved, allowing for the selective adsorption of specific compounds based on their molecular size. Many kinds of materials exhibit some molecular sieves, but zeolites dominate the field. Zeolites are almost always aluminosilicates, or variants where some or all of the Si or Al centers are replaced by similarly charged elements. Sieving process The diameters of the pores that comprise molecular sieves are similar in size to small molecules. Large molecules cannot enter or be adsorbed, while smaller molecules can. As a mixture of molecules migrates through the stationary bed of porous, semi-solid substance referred to as a sieve (or matrix), the components of the highest molecular weight (which are unable to pass int ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vacuum Furnace
A vacuum furnace is a type of furnace in which the product in the furnace is surrounded by a vacuum during processing. The absence of air or other gases prevents oxidation, heat loss from the product through convection, and removes a source of contamination. This enables the furnace to heat materials (typically metals and ceramics) to temperatures as high as with select materials. Maximum furnace temperatures and vacuum levels depend on melting points and vapor pressures of heated materials. Vacuum furnaces are used to carry out processes such as annealing, brazing, sintering and heat treatment with high consistency and low contamination. Characteristics of a vacuum furnace are: * Uniform temperatures in the range. * Commercially available vacuum pumping systems can reach vacuum levels as low as * Temperature can be controlled within a heated zone, typically surrounded by heat shielding or insulation. * Low contamination of the product by carbon, oxygen and other gases. * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetylacetonate Complex
Metal acetylacetonates are coordination complexes derived from the acetylacetonate anion () and metal ions, usually transition metals. The bidentate ligand acetylacetonate is often abbreviated acac. Typically both oxygen atoms bind to the metal to form a six-membered chelate ring. The simplest complexes have the formula M(acac)3 and M(acac)2. Mixed-ligand complexes, e.g. VO(acac)2, are also numerous. Variations of acetylacetonate have also been developed with myriad substituents in place of methyl (RCOCHCO−). Many such complexes are soluble in organic solvents, in contrast to the related metal halides. Because of these properties, acac complexes are sometimes used as catalyst precursors and reagents. Applications include their use as NMR "shift reagents" and as catalysts for organic synthesis, and precursors to industrial hydroformylation catalysts. in some cases also binds to metals through the central carbon atom; this bonding mode is more common for the third-row transition me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laboratory Equipment
A laboratory (; ; colloquially lab) is a facility that provides controlled conditions in which scientific or technological research, experiments, and measurement may be performed. Laboratories are found in a variety of settings such as schools, universities, privately owned research institutions, corporate research and testing facilities, government regulatory and forensic investigation centers, physicians' offices, clinics, hospitals, regional and national referral centers, and even occasionally personal residences. Overview The organisation and contents of laboratories are determined by the differing requirements of the specialists working within. A physics laboratory might contain a particle accelerator or vacuum chamber, while a metallurgy laboratory could have apparatus for casting or refining metals or for testing their strength. A chemist or biologist might use a wet laboratory, while a psychologist's laboratory might be a room with one-way mirrors and hidden cameras in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
