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Chloroiodomethane
Chloroiodomethane is the halomethane with the formula is . It is a colorless liquid of use in organic synthesis. Together with other iodomethanes, chloroiodomethane is produced by some microorganisms. Applications Chloroiodomethane is used in cyclopropanation (''Simmon-Smith reaction''), where it often replaces diiodomethane because of higher yields and selectivity. It is also used in Mannich reaction, aminomethylation, epoxidation, ring opening and addition to terminal alkenes. It is a precursor to chloromethylenating agent Ph3P=CHCl. It reacts with organolithium compounds to give chloromethyllithium (ClCH2Li). Crystallography It crystallizes orthorhombic crystal system with space group ''Pnma'' with lattice constants A lattice constant or lattice parameter is one of the physical dimensions and angles that determine the geometry of the unit cells in a crystal lattice, and is proportional to the distance between atoms in the crystal. A simple cubic crystal has ...: ''a'' = ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chloromethane
Chloromethane, also called methyl chloride, Refrigerant-40, R-40 or HCC 40, is an organic compound with the chemical formula . One of the haloalkanes, it is a colorless, odorless, flammable gas. Methyl chloride is a crucial reagent in industrial chemistry, although it is rarely present in consumer products, and was formerly utilized as a refrigerant. Occurrence Chloromethane is an abundant organohalogen, anthropogenic or natural, in the atmosphere. Marine Laboratory cultures of marine phytoplankton (''Phaeodactylum tricornutum'', ''Phaeocystis'' sp., ''Thalassiosira weissflogii'', ''Chaetoceros calcitrans'', ''Isochrysis'' sp., ''Porphyridium'' sp., ''Synechococcus'' sp., ''Tetraselmis'' sp., ''Prorocentrum'' sp., and ''Emiliana huxleyi'') produce CH3Cl, but in relatively insignificant amounts. An extensive study of 30 species of polar macroalgae revealed the release of significant amounts of CH3Cl in only ''Gigartina skottsbergii'' and ''Gymnogongrus antarcticus''. Biogenesis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bromochloromethane
Bromochloromethane or methylene bromochloride and Halon 1011 is a mixed halomethane. It is a heavy low-viscosity liquid with refractive index 1.4808. Halon 1011 was invented for use in fire extinguishers in Germany during the mid-1940s, in an attempt to create a less toxic, more effective alternative to carbon tetrachloride. This was a concern in aircraft and tanks as carbon tetrachloride produced highly toxic by-products when discharged onto a fire. It was slightly less toxic, and used up until the late 1960s, being officially banned by the NFPA for use in fire extinguishers in 1969, as safer and more effective agents such as halon 1211 and 1301 were developed. Due to its ozone depletion potential its production was banned from January 1, 2002, at the ''Eleventh Meeting of the Parties for the Montreal Protocol on Substances that Deplete the Ozone Layer''. Bromochloromethane's biodegradation is catalyzed by the hydrolase enzyme alkylhalidase: :CH2BrCl + H2O → CH2O + HBr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dibromochloromethane
Dibromochloromethane is a colorless to yellow, heavy and nonflammable compound with formula . It is a trihalomethane. The substance has a sweet odour. Small quantities of dibromochloromethane are produced in ocean by algae. Applications Dibromochloromethane was formerly used as a flame retardant and as an intermediate in chemicals manufacturing. Today it is used only as a laboratory reagent. Dibromochloromethane is also a disinfection byproduct, formed by the reaction of chlorine with natural organic matter and bromide ions in the raw water supply. As a result, it is commonly found in chlorinated drinking water. Also, it is able to reduce methane production in ruminants by 79 % See also * Asparagopsis taxiformis ''Asparagopsis taxiformis'', (red sea plume or limu kohu) formerly ''A. sanfordiana'', is a species of red algae, with cosmopolitan distribution in tropical to warm temperate waters. Researchers have demonstrated that feeding ruminants a diet c ... References Ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2-Chloroethanol
2-Chloroethanol (also called ethylene chlorohydrin or glycol chlorohydrin) is an organic chemical compound with the chemical formula HOCH2CH2Cl and the ''simplest'' beta-halohydrin (chlorohydrin). This colorless liquid has a pleasant ether-like odor. It is miscible with water. The molecule is bifunctional, consisting of both an alkyl chloride and an alcohol functional group. Synthesis and applications 2-Chloroethanol is produced by treating ethylene with hypochlorous acid: : 2-Chloroethanol was once produced on a large scale as a precursor to ethylene oxide: : :HOCH2CH2Cl + NaOH → C2H4O + NaCl + H2O This application has been supplanted by the more economic direct oxidation of ethylene. Otherwise chloroethanol is still used in the production of pharmaceuticals, biocides, and plasticizers. Many of these applications entail its use in installing 2-hydroxyethyl groups. Several dyes are prepared by the alkylation of aniline derivatives with chloroethanol. It is also used for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halomethane
Halomethane compounds are derivatives of methane () with one or more of the hydrogen atoms replaced with halogen atoms ( F, Cl, Br, or I). Halomethanes are both naturally occurring, especially in marine environments, and human-made, most notably as refrigerants, solvents, propellants, and fumigants. Many, including the chlorofluorocarbons, have attracted wide attention because they become active when exposed to ultraviolet light found at high altitudes and destroy the Earth's protective ozone layer. Structure and properties Like methane itself, halomethanes are tetrahedral molecules. The halogen atoms differ greatly in size and charge from hydrogen and from each other. Consequently, most halomethanes deviate from the perfect tetrahedral symmetry of methane.Günter Siegemund, Werner Schwertfeger, Andrew Feiring, Bruce Smart, Fred Behr, Herward Vogel, Blaine McKusick “Fluorine Compounds, Organic” Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2002. The ph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Synthesis
Organic synthesis is a special branch of chemical synthesis and is concerned with the intentional construction of organic compounds. Organic molecules are often more complex than inorganic compounds, and their synthesis has developed into one of the most important branches of organic chemistry. There are several main areas of research within the general area of organic synthesis: ''total synthesis'', ''semisynthesis'', and ''methodology''. Total synthesis A total synthesis is the complete chemical synthesis of complex organic molecules from simple, commercially available petrochemical or natural precursors. Total synthesis may be accomplished either via a linear or convergent approach. In a ''linear'' synthesis—often adequate for simple structures—several steps are performed one after another until the molecule is complete; the chemical compounds made in each step are called synthetic intermediates. Most often, each step in a synthesis refers to a separate rea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclopropanation
In organic chemistry, cyclopropanation refers to any chemical process which generates cyclopropane () rings. It is an important process in modern chemistry as many useful compounds bear this motif; for example pyrethroids and a number of quinolone antibiotics (ciprofloxacin, sparfloxacin, etc.). However, the high ring strain present in cyclopropanes makes them challenging to produce and generally requires the use of highly reactive species, such as carbenes, ylids and carbanions. Many of the reactions proceed in a cheletropic manner. Approaches From alkenes using carbenoid reagents Several methods exist for converting alkenes to cyclopropane rings using carbene type reagents. As carbenes themselves are highly reactive it is common for them to be used in a stabilised form, referred to as a carbenoid. Simmons–Smith reaction In the Simmons–Smith reaction the reactive carbenoid is iodomethylzinc iodide, which is typically formed by a reaction between diiodomethane and a z ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diiodomethane
Diiodomethane or methylene iodide, commonly abbreviated "MI", is an organoiodine compound. Diiodomethane is a colorless liquid; however, it decomposes upon exposure to light liberating iodine, which colours samples brownish. It is slightly soluble in water, but soluble in organic solvents. It has a relatively high refractive index of 1.741, and a surface tension of 0.0508 N·m−1.Website of Krüss'' (8.10.2009) Uses Because of its high density, diiodomethane is used in the determination of the density of mineral and other solid samples. It can also be used as an optical contact liquid, in conjunction with the gemmological refractometer, for determining the refractive index of certain gemstones. Diiodomethane is a reagent for installing the CH2 group. In the Simmons–Smith reaction, it is a source of methylene. In fact the Simmons–Smith reaction does not produce free carbene but proceeds via Zn-CH2I intermediates. Diiodomethane is also a source of the equivalent of CH22+. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mannich Reaction
In organic chemistry, the Mannich reaction is a three-component organic reaction that involves the amino alkylation of an acidic proton next to a carbonyl () functional group by formaldehyde () and a primary or secondary amine () or ammonia (). The final product is a β-amino-carbonyl compound also known as a Mannich base. Reactions between aldimines and α-methylene carbonyls are also considered Mannich reactions because these imines form between amines and aldehydes. The reaction is named after Carl Mannich. center, 500px, Scheme 1 - Ammonia or an amine reacts with formaldehyde and an alpha acidic proton of a carbonyl compound to a beta amino carbonyl compound. The Mannich reaction starts with the nucleophilic addition of an amine to a carbonyl group followed by dehydration to the Schiff base. The Schiff base is an electrophile which reacts in a second step in an electrophilic addition with an enol formed from a carbonyl compound containing an acidic alpha-proton. The Mann ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epoxidation
In organic chemistry, an epoxide is a cyclic ether () with a three-atom ring. This ring approximates an equilateral triangle, which makes it strained, and hence highly reactive, more so than other ethers. They are produced on a large scale for many applications. In general, low molecular weight epoxides are colourless and nonpolar, and often volatile. Nomenclature A compound containing the epoxide functional group can be called an epoxy, epoxide, oxirane, and ethoxyline. Simple epoxides are often referred to as oxides. Thus, the epoxide of ethylene (C2H4) is ethylene oxide (C2H4O). Many compounds have trivial names; for instance, ethylene oxide is called "oxirane". Some names emphasize the presence of the epoxide functional group, as in the compound ''1,2-epoxyheptane'', which can also be called ''1,2-heptene oxide''. A polymer formed from epoxide precursors is called an '' epoxy'', but such materials do not contain epoxide groups (or contain only a few residual epoxy gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
(Chloromethylene)triphenylphosphorane
(Chloromethylene)triphenylphosphorane is the organophosphorus compound with he formula Ph3P=CHCl (Ph = phenyl). It is a white solid but is usually generated and used in situ as a reagent in organic synthesis. It is structurally and chemically related to methylenetriphenylphosphorane. The reagent is prepared from the chloromethylphosphonium salt h3PCH2Cll by treatment with strong base. The phosphonium compound is generated by treatment of triphenylphosphine with chloroiodomethane. (Chloromethylene)triphenylphosphorane converts aldehydes to vinyl chlorides: :RCHO + Ph3P=CHCl → RCH=CHCl + Ph3PO These vinyl chlorides undergo dehydrochlorination to give alkyne \ce \ce Acetylene \ce \ce \ce Propyne \ce \ce \ce \ce 1-Butyne In organic chemistry, an alkyne is an unsaturated hydrocarbon containing at least one carbon—carbon triple bond. The simplest acyclic alkynes with only one triple bond and n ...s: :RCH=CHCl + NaN(SiMe3)2 → RC≡CH + NaCl + HN(SiMe3)2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orthorhombic Crystal System
In crystallography, the orthorhombic crystal system is one of the 7 crystal systems. Orthorhombic lattices result from stretching a cubic lattice along two of its orthogonal pairs by two different factors, resulting in a rectangular prism with a rectangular base (''a'' by ''b'') and height (''c''), such that ''a'', ''b'', and ''c'' are distinct. All three bases intersect at 90° angles, so the three lattice vectors remain mutually orthogonal. Bravais lattices There are four orthorhombic Bravais lattices: primitive orthorhombic, base-centered orthorhombic, body-centered orthorhombic, and face-centered orthorhombic. For the base-centered orthorhombic lattice, the primitive cell has the shape of a right rhombic prism;See , row oC, column Primitive, where the cell parameters are given as a1 = a2, α = β = 90° it can be constructed because the two-dimensional centered rectangular base layer can also be described with primitive rhombic axes. Note that the length a of the primiti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
