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Ružička Reaction
Ketonic decarboxylation (also known as decarboxylative ketonization) is a type of organic reaction involving decarboxylation, converting two equivalents of a carboxylic acid () to a symmetric ketone (). The reaction typically requires heat and a metal catalyst, and generally proceeds in low yields. It can be thought of as a decarboxylative Claisen condensation. Water and carbon dioxide are byproducts: : base (chemistry), Bases promote this reaction. The reaction mechanism is proposed to involve nucleophilic attack of the alpha-carbon of one acid group on the other carboxylic acid group, possibly as a concerted reaction with the decarboxylation. The initial formation of an intermediate carbanion via decarboxylation of one of the acid groups prior to the nucleophilic attack is unlikely since the byproduct resulting from the carbanion's protonation by the acid has not been reported. This reaction is different from oxidative decarboxylation, which proceeds through a Radical (chemistr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Reaction
Organic reactions are chemical reactions involving organic compounds. The basic organic chemistry reaction types are addition reactions, elimination reactions, substitution reactions, pericyclic reactions, rearrangement reactions, mechanistic organic photochemistry, photochemical reactions and organic redox reaction, redox reactions. In organic synthesis, organic reactions are used in the construction of new organic molecules. The production of many man-made chemicals such as drugs, plastics, food additives, fabrics depend on organic reactions. The oldest organic reactions are combustion of organic fuels and saponification of fats to make soap. Modern organic chemistry starts with the Wöhler synthesis in 1828. In the history of the Nobel Prize in Chemistry awards have been given for the invention of specific organic reactions such as the Grignard reaction in 1912, the Diels–Alder reaction in 1950, the Wittig reaction in 1979 and olefin metathesis in 2005. Classifications Organ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcium Acetate
Calcium acetate is a chemical compound which is a calcium salt of acetic acid. It has the formula Ca(C2H3O2)2. Its standard name is calcium acetate, while calcium ethanoate is the systematic name. An older name is acetate of lime. The anhydrous form is very hygroscopic; therefore the monohydrate (Ca(CH3COO)2•H2O) is the common form. Production Calcium acetate can be prepared by soaking calcium carbonate (found in eggshells, or in common carbonate rocks such as limestone or marble) or hydrated lime in vinegar: :CaCO3(s) + 2CH3COOH(aq) → Ca(CH3COO)2(aq) + H2O(l) + CO2(g) :Ca(OH)2(s) + 2CH3COOH(aq) → Ca(CH3COO)2(aq) + 2H2O(l) Since both reagents would have been available pre-historically, the chemical would have been observable as crystals then. Uses * In kidney disease, blood levels of phosphate may rise (called hyperphosphatemia) leading to bone problems. Calcium acetate binds phosphate in the diet to lower blood phosphate levels. * Calcium acetate is used as a food additi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manganese Dioxide
Manganese dioxide is the inorganic compound with the formula . This blackish or brown solid occurs naturally as the mineral pyrolusite, which is the main ore of manganese and a component of manganese nodules. The principal use for is for dry-cell batteries, such as the alkaline battery and the zinc–carbon battery, although it is also used for other battery chemistries such as aqueous zinc-ion batteries.. is also used as a pigment and as a precursor to other manganese compounds, such as . It is used as a reagent in organic synthesis, for example, for the oxidation of allylic alcohols. has an α- polymorph that can incorporate a variety of atoms (as well as water molecules) in the "tunnels" or "channels" between the manganese oxide octahedra. There is considerable interest in as a possible cathode for lithium-ion batteries. Structure Several polymorphs of are claimed, as well as a hydrated form. Like many other dioxides, crystallizes in the rutile crystal structure (t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cerium(IV) Oxide
Cerium(IV) oxide, also known as ceric oxide, ceric dioxide, ceria, cerium oxide or cerium dioxide, is an oxide of the rare-earth metal cerium. It is a pale yellow-white powder with the chemical formula CeO2. It is an important commercial product and an intermediate in the purification of the element from the ores. The distinctive property of this material is its reversible conversion to a Non-stoichiometric compound, non-stoichiometric oxide. Production Cerium occurs naturally as oxides, always as a mixture with other rare-earth elements. Its principal ores are bastnaesite and monazite. After extraction of the metal ions into aqueous base, Ce is separated from that mixture by addition of an oxidant followed by adjustment of the pH. This step exploits the low solubility of CeO2 and the fact that other rare-earth elements resist oxidation.. Cerium(IV) oxide is formed by the calcination of cerium oxalate or cerium hydroxide. Cerium also forms cerium(III) oxide, , which is unst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biomass
Biomass is a term used in several contexts: in the context of ecology it means living organisms, and in the context of bioenergy it means matter from recently living (but now dead) organisms. In the latter context, there are variations in how biomass is defined, e.g., only from plants, from plants and algae, from plants and animals. The vast majority of biomass used for bioenergy does come from plants and fecal matter. Bioenergy is a type of renewable energy that the bioenergy industry claims has the potential to assist with climate change mitigation. Uses in different contexts Ecology * Biomass (ecology), the mass of living biological organisms in a given area or ecosystem at a given time. This can be the biomass of particular species or the biomass of a particular community or habitat. Energy * Biomass (energy), biomass used for energy production or in other words: biological mass used as a renewable energy source (usually produced through agriculture, forestry or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnesium Stearate
Magnesium stearate is the chemical compound with the formula . It is a soap, consisting of salt containing two equivalents of stearate (the anion of stearic acid) and one magnesium cation (Mg2+). Magnesium stearate is a white, water-insoluble powder. Its applications exploit its softness, insolubility in many solvents, and low toxicity. It is used as a release agent and as a component or lubricant in the production of pharmaceuticals and cosmetics.Angelo Nora, Alfred Szczepanek, Gunther Koenen, "Metallic Soaps" in Ullmann's Encyclopedia of Industrial Chemistry 2005 Wiley-VCH, Weinheim. Manufacturing Magnesium stearate is produced by the reaction of sodium stearate with magnesium salts or by treating magnesium oxide with stearic acid. Uses Magnesium stearate is often used in food preparations as a anti-adherent and anticaking agent. in the manufacture of medical tablets, capsules and powders. In this regard, the substance is also useful because it has lubricating properties, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Valeric Acid
Valeric acid or pentanoic acid is a straight-chain alkyl carboxylic acid with the chemical formula . Like other low-molecular-weight carboxylic acids, it has an unpleasant odor. It is found in the perennial flowering plant '' Valeriana officinalis'', from which it gets its name. Its primary use is in the synthesis of its esters. Salts and esters of valeric acid are known as valerates or pentanoates. Volatile esters of valeric acid tend to have pleasant odors and are used in perfumes and cosmetics. Several, including ethyl valerate and pentyl valerate are used as food additives because of their fruity flavors. History Valeric acid is a minor constituent of the perennial flowering plant valerian (''Valeriana officinalis''), from which it gets its name. The dried root of this plant has been used medicinally since antiquity. The related isovaleric acid shares its unpleasant odor and their chemical identity was investigated by oxidation of the components of fusel alcohol, whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
5-Nonanone
5-Nonanone, or dibutyl ketone, is the organic compound with the formula (CH3CH2CH2CH2)2CO. This colorless liquid is a symmetrical ketone. Synthesis 5-Nonanone, which is potentially of interest as a diesel fuel, can be produced from levulinic acid, which can be produced from fructose. Levulinic acid is converted to valeric acid, which undergoes ketonization. Toxicology Metabolic pathway 5-Nonanone was expected to be metabolized to a γ-diketone (a diketone with the second oxygen three carbons away from the first, e.g. 2,5- or 3,6-diketones). Metabolic studies confirmed the ''in vivo'' ω-oxidation of 5-nonanone to 2,5-nonanedione and 2-hexanone. Subsequent oxidative and decarboxylative steps also produce 2,5-hexanedione. Besides these metabolites, 38% of the 5-nonanone dose is converted to carbon dioxide. No unchanged 5-nonanone is detected in the urine after administration. Of these metabolites, 2,5-hexanedione is believed to be the most neurotoxic compound. Of all the afo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tube Furnace
A tube furnace is an electric heating device used to conduct syntheses and purifications of inorganic compounds and occasionally in organic synthesis. One possible design consists of a cylindrical cavity surrounded by heating coils that are embedded in a thermally insulating matrix. Temperature can be controlled via feedback from a thermocouple. More elaborate tube furnaces have two (or more) heating zones useful for transport experiments. Some digital temperature controllers provide an RS-232 interface, and permit the operator to program segments for uses like ramping, soaking, sintering, and more. Advanced materials in the heating elements, such as molybdenum disilicide (MoSi2) offered in certain models can now produce working temperatures up to 1800 °C. This facilitates more sophisticated applications. Common material for the reaction tubes include alumina, Pyrex, and fused quartz, or in the case of corrosive materials molybdenum or tungsten tubes can be used. The tube ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manganese(II) Oxide
Manganese(II) oxide is an inorganic compound with chemical formula MnO.Arno H. Reidies "Manganese Compounds" Ullmann's Encyclopedia of Chemical Technology 2007; Wiley-VCH, Weinheim. It forms green crystals. The compound is produced on a large scale as a component of fertilizers and food additives. Structure, stoichiometry, reactivity Like many metal monoxides, MnO adopts the rock salt structure, where cations and anions are both octahedrally coordinated. Also like many metal oxides, manganese(II) oxide is often nonstoichiometric: its composition can vary from MnO to MnO1.045. Below 118 K, MnO is antiferromagnetic. MnO has the distinction of being one of the first compounds to have its magnetic structure determined by neutron diffraction, the report appearing in 1951. This study showed that the Mn2+ ions form a face centered cubic magnetic sub-lattice where there are ferromagnetically coupled sheets that are anti-parallel with adjacent sheets. Manganese(II) oxide undergoes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propanoic Acid
Propionic acid (, from the Greek words πρῶτος : ''prōtos'', meaning "first", and πίων : ''píōn'', meaning "fat"; also known as propanoic acid) is a naturally occurring carboxylic acid with chemical formula . It is a liquid with a pungent and unpleasant smell somewhat resembling body odor. The anion as well as the salts and esters of propionic acid are known as propionates or propanoates. About half of the world production of propionic acid is consumed as a preservative for both animal feed and food for human consumption. It is also useful as an intermediate in the production of other chemicals, especially polymers. History Propionic acid was first described in 1844 by Johann Gottlieb, who found it among the degradation products of sugar. Over the next few years, other chemists produced propionic acid by different means, none of them realizing they were producing the same substance. In 1847, French chemist Jean-Baptiste Dumas established all the acids to be the sa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
