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Dimethylglyoxime
Dimethylglyoxime is a chemical compound described by the formula CH3C(NOH)C(NOH)CH3. Its abbreviation is dmgH2 for neutral form, and dmgH− for anionic form, where H stands for hydrogen. This colourless solid is the dioxime derivative of the diketone butane-2,3-dione (also known as diacetyl). DmgH2 is used in the analysis of palladium or nickel. Its coordination complexes are of theoretical interest as models for enzymes and as catalysts. Many related ligands can be prepared from other diketones, e.g. benzil. Preparation and reactions Dimethylglyoxime can be prepared from butanone first by reaction with ethyl nitrite to give biacetyl monoxime. The second oxime is installed using sodium hydroxylamine monosulfonate: 2,3-Butanediamine is produced by reduction of dimethylglyoxime with lithium aluminium hydride. Complexes Dimethylglyoxime forms complexes with metals including nickel, palladium and cobalt. These complexes are used to separate those cations from solutions of met ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nickel Bis(dimethylglyoximate)
Nickel bis(dimethylglyoximate) is the coordination complex with the formula Ni NC(CH3)C(CH3)NOHsub>2. The compound is a bright red solid. It achieved prominence for its use in the qualitative analysis of nickel. Structure The geometry of the nickel(II) ion is square planar. It is surrounded by two equivalents of the conjugate base (dmgH−) of dimethylglyoxime (dmgH2). The pair of organic ligands are joined through hydrogen bonds to give a macrocyclic ligand. The complex is distinctively colored and insoluble leading to its use as a chelating agent in the gravimetric analysis of nickel. The use of dimethylglyoxime as a reagent to detect nickel Nickel is a chemical element; it has symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive, but large pieces are slo ... was reported by L. A. Chugaev in 1905.{{cite journal , title = Über ein neu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Butanone
Butanone, also known as methyl ethyl ketone (MEK) or ethyl methyl ketone, is an organic compound with the formula CH3C(O)CH2CH3. This colorless liquid ketone has a sharp, sweet odor reminiscent of acetone. It is produced industrially on a large scale, but occurs in nature only in trace amounts.Wilhelm Neier, Guenter Strehlke "2-Butanone" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2002. It is partially soluble in water, and is commonly used as an industrial solvent. It is an isomer of another solvent, tetrahydrofuran. Production Butanone may be produced by oxidation of 2-butanol. The dehydrogenation of 2-butanol is catalysed by copper, zinc, or bronze: :CH3CH(OH)CH2CH3 → CH3C(O)CH2CH3 + H2 This is used to produce approximately 700 million kilograms yearly. Other syntheses that have been examined but not implemented include Wacker oxidation of 2-butene and oxidation of isobutylbenzene, which is analogous to the industrial production of ace ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethyl Nitrite
The chemical compound ethyl nitrite is an alkyl nitrite with a chemical formula C2H5NO2. It may be prepared from ethanol. : Uses It is used as a reagent with butanone to yield the dimethylglyoxime end product. : Ethyl nitrite is the main ingredient in a traditional ethanol-based South African remedy for colds and flu known as ''Witdulsies'', which is sold in pharmacies. It is known as a traditional Afrikaans remedy; the same remedy is apparently made by the Amish in the US. However, FDA has blocked over-the-counter sales of this same remedy, known in the US as ''sweet nitrite'' or ''sweet spirit of nitre'', since 1980. Its use has been associated with fatal methemoglobinemia. Methemoglobinemia Methemoglobinemia, or methaemoglobinaemia, is a condition of elevated methemoglobin in the blood. Symptoms may include headache, dizziness, shortness of breath, nausea, poor muscle coordination, and blue-colored skin (cyanosis). Complications ma ... is the primary toxic effect of e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biacetyl Monoxime
Diacetyl monoxime is a chemical compound described by the formula CH3C(O)C(NOH)CH3. This colourless solid is the monooxime derivative of the diketone butane-2,3-dione (also known as diacetyl and biacetyl). Its biological effects include inhibiting certain ATPases. Preparation The compound can be prepared from butanone by reaction with ethyl nitrite. It is an intermediate in the preparation of dimethylglyoxime Dimethylglyoxime is a chemical compound described by the formula CH3C(NOH)C(NOH)CH3. Its abbreviation is dmgH2 for neutral form, and dmgH− for anionic form, where H stands for hydrogen. This colourless solid is the dioxime derivative of the dike ...: : Uses Diacetyl monoxime can be used with thiosemicarbazide to selectively detect small amounts of urea in the presence of other nitrogen-containing compounds. References {{Reflist Ketoximes Chelating agents ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxime
In organic chemistry, an oxime is an organic compound belonging to the imines, with the general Chemical formula, formula , where R is an organic Side chain, side-chain and R' may be hydrogen, forming an aldoxime, or another organic functional group, group, forming a ketoxime. O-substituted oximes form a closely related family of compounds. Amidoximes are oximes of amides () with general structure . Oximes are usually generated by the reaction of hydroxylamine with aldehydes () or ketones (). The term ''oxime'' dates back to the 19th century, a combination of the words ''oxygen'' and ''imine''. Structure and properties If the two side-chains on the central carbon are different from each other—either an aldoxime, or a ketoxime with two different "R" groups—the oxime can often have two different geometric stereoisomeric forms according to the E/Z configuration, ''E''/''Z'' configuration. An older terminology of Descriptor (chemistry)#syn, anti, ''syn'' and ''anti'' was used to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ligand
In coordination chemistry, a ligand is an ion or molecule with a functional group that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's electron pairs, often through Lewis acids and bases, Lewis bases. The nature of metal–ligand bonding can range from covalent bond, covalent to ionic bond, ionic. Furthermore, the metal–ligand bond order can range from one to three. Ligands are viewed as Lewis bases, although rare cases are known to involve Lewis acids and bases, Lewis acidic "ligands". Metals and metalloids are bound to ligands in almost all circumstances, although gaseous "naked" metal ions can be generated in a high vacuum. Ligands in a complex dictate the reactivity (chemistry), reactivity of the central atom, including ligand substitution rates, the reactivity of the ligands themselves, and redox. Ligand selection requires critical consideration in many practical are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palladium Chloride
Palladium(II) chloride, also known as palladium dichloride and palladous chloride, are the chemical compounds with the formula PdCl2. PdCl2 is a common starting material in palladium chemistry – palladium-based catalysts are of particular value in organic synthesis. It is prepared by the reaction of chlorine with palladium metal at high temperatures. Structure Two forms of PdCl2 are known, denoted α and β. In both forms, the palladium centres adopt a square-planar coordination geometry that is characteristic of Pd(II). Furthermore, in both forms, the Pd(II) centers are linked by μ2-chloride bridges. The α-form of PdCl2 is a polymer, consisting of "infinite" slabs or chains. The β-form of PdCl2 is molecular, consisting of an octahedral cluster of six Pd atoms. Each of the twelve edges of this octahedron is spanned by Cl−. PtCl2 adopts similar structures, whereas NiCl2 adopts the CdCl2 motif, featuring hexacoordinated Ni(II). Two further polymorphs, γ-PdCl2 and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Precious Metals Refining
In metallurgy, refining consists of purifying an impure metal. It is to be distinguished from other processes such as smelting and calcining in that those two involve a chemical change to the raw material, whereas in refining the final material is chemically identical to the raw material. Refining thus increases the purity of the raw material via processing. There are many processes including pyrometallurgical and hydrometallurgical techniques. Lead Cupellation One ancient process for extracting the silver from lead was cupellation. This process involved melting impure lead samples in a cupel, a small porous container designed for purification that would aid in the oxidation process, while being able to withstand the heat needed to melt these metals in a furnace. This reaction would oxidize the lead to litharge, along with any other impurities present, whereas the silver would not get oxidized. In the 18th century, the process was carried on using a kind of reverberatory ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gravimetric Analysis
Gravimetric analysis describes a set of methods used in analytical chemistry for the quantitative determination of an analyte (the ion being analyzed) based on its mass. The principle of this type of analysis is that once an ion's mass has been determined as a unique compound, that known measurement can then be used to determine the same analyte's mass in a mixture, as long as the relative quantities of the other constituents are known. The four main types of this method of analysis are ''precipitation'', ''volatilization'', ''electro-analytical'' and ''miscellaneous physical method''. The methods involve changing the phase of the analyte to separate it in its pure form from the original mixture and are quantitative measurements. Precipitation method The precipitation method is the one used for the determination of the amount of calcium in water. Using this method, an excess of oxalic acid, H2C2O4, is added to a measured, known volume of water. By adding a reagent, here ammon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cobalt
Cobalt is a chemical element; it has Symbol (chemistry), symbol Co and atomic number 27. As with nickel, cobalt is found in the Earth's crust only in a chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, produced by reductive smelting, is a hard, lustrous, somewhat brittle, gray metal. Cobalt-based blue pigments (cobalt blue) have been used since antiquity for jewelry and paints, and to impart a distinctive blue tint to glass. The color was long thought to be due to the metal bismuth. Miners had long used the name ''kobold ore'' (German language, German for ''goblin ore'') for some of the blue pigment-producing minerals. They were so named because they were poor in known metals and gave off poisonous arsenic-containing fumes when smelted. In 1735, such ores were found to be reducible to a new metal (the first discovered since ancient times), which was ultimately named for the ''kobold''. Today, some cobalt is produced sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lithium Aluminium Hydride
Lithium aluminium hydride, commonly abbreviated to LAH, is an inorganic compound with the chemical formula or . It is a white solid, discovered by Finholt, Bond and Schlesinger in 1947. This compound is used as a reducing agent in organic synthesis, especially for the reduction of esters, carboxylic acids, and amides. The solid is dangerously reactive toward water, releasing gaseous hydrogen (H2). Some related derivatives have been discussed for hydrogen storage. Properties, structure, preparation LAH is a colourless solid but commercial samples are usually gray due to contamination. This material can be purified by recrystallization from diethyl ether. Large-scale purifications employ a Soxhlet extractor. Commonly, the impure gray material is used in synthesis, since the impurities are innocuous and can be easily separated from the organic products. The pure powdered material is pyrophoric, but not its large crystals. Some commercial materials contain mineral oil to inhibit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2,3-Butanediamine
2,3-Butanediamine are organic compounds with the formula CH3CH(NH2)CH(NH2)CH3. Three stereoisomers exist, meso and a pair of enantiomers. These diamines form complexes with transition metals. Synthesis 2,3-Butanediamines can be prepared by hydrolyzing 2-ethoxy-4,5-dihydro-4,5-dimethylimidazole with barium hydroxide. Alternative, it is produced by reduction of dimethylglyoxime with lithium aluminium hydride. The meso and the d,l diastereomers can be separated by fractional crystallization of the hydrochlorides. The enantiomers have been resolved using tartrate salts. Reactions In coordination chemistry, 2,3-butanediamine (abbreviated bn) has illuminates aspects of the stereochemistry. The structure of o(meso-2,3-butanediamine)2CO3sup>+ confirms the presence of the rarely observed axial methyl groups on each of the diamine-cobalt rings. Related compounds *1,2-Diaminopropane 1,2-Diaminopropane (propane-1,2-diamine) is organic compound with the formula CHCH(NH)CHNH. A col ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
