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1,2,4,5-tetrachlorobenzene
Tetrachlorobenzene is any of three isomeric chlorobenzenes with the molecular formula . They differ by the positions of the chlorine atoms around the ring. Tetrachlorobenzenes are colorless crystalline compounds. Properties Synthesis 1,2,4,5-Tetrachlorobenzene can be produced by electrophilic halogenation of benzene Benzene is an Organic compound, organic chemical compound with the Chemical formula#Molecular formula, molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar hexagonal Ring (chemistry), ring with one hyd ...s and some chlorobenzenes. 1,2,3,4-Tetrachlorobenzene can only be produced by chlorination of 1,3,5-trichlorobenzene. Uses 1,2,4,5-Tetrachlorobenzene once was used as intermediates in the production of pesticides, specifically 2,4,5-trichlorophenol and 2,4,5-trichlorophenoxyacetic acid. This method has been discontinued because it also produced 2,3,7,8-tetrachlorodibenzo-p-dioxin. See also * Tetrabromobenzene * T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isomeric
In chemistry, isomers are molecules or polyatomic ions with identical molecular formula – that is, the same number of atoms of each element – but distinct arrangements of atoms in space. ''Isomerism'' refers to the existence or possibility of isomers. Isomers do not necessarily share similar chemical or physical properties. Two main forms of isomerism are structural (or constitutional) isomerism, in which '' bonds'' between the atoms differ; and stereoisomerism (or spatial isomerism), in which the bonds are the same but the ''relative positions'' of the atoms differ. Isomeric relationships form a hierarchy. Two chemicals might be the same constitutional isomer, but upon deeper analysis be stereoisomers of each other. Two molecules that are the same stereoisomer as each other might be in different conformational forms or be different isotopologues. The depth of analysis depends on the field of study or the chemical and physical properties of interest. The English word "is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorobenzenes
Chlorobenzenes are a group of aryl chlorides/ halobenzenes consisting of one or more chlorine atoms as substituents on a benzene core. They have the formula C6H6–''n''Cl''n'', where ''n'' = 1–6 is the number of chlorine atoms. Depending on the number of chlorine substituents, there may be several constitutional isomers possible. * Monochlorobenzene * Dichlorobenzene ** 1,2-Dichlorobenzene ** 1,3-Dichlorobenzene ** 1,4-Dichlorobenzene * Trichlorobenzene ** 1,2,3-Trichlorobenzene ** 1,2,4-Trichlorobenzene ** 1,3,5-Trichlorobenzene * Tetrachlorobenzene ** 1,2,3,4-Tetrachlorobenzene ** 1,2,3,5-Tetrachlorobenzene ** 1,2,4,5-Tetrachlorobenzene * Pentachlorobenzene * Hexachlorobenzene Hexachlorobenzene, or perchlorobenzene, is an aryl chloride and a six-substituted chlorobenzene with the molecular formula C6Cl6. It is a fungicide formerly used as a seed treatment, especially on wheat to control the fungal disease bunt. Its u ... See also * Fluorobenzenes * Bromobenzen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrophilic Halogenation
In organic chemistry, an electrophilic aromatic halogenation is a type of electrophilic aromatic substitution. This organic reaction is typical of aromatic compounds and a very useful method for adding substituents to an aromatic system. : A few types of aromatic compounds, such as phenol, will react without a catalyst, but for typical benzene derivatives with less reactive substrates, a Lewis acid is required as a catalyst. Typical Lewis acid catalysts include , , and . These work by forming a highly electrophilic complex which is attacked by the benzene ring. Reaction mechanism The reaction mechanism for chlorination of benzene is the same as bromination of benzene. Iron(III) bromide and iron(III) chloride become inactivated if they react with water, including moisture in the air. Therefore, they are generated by adding iron filings to bromine or chlorine. Here is the mechanism of this reaction: : The mechanism for iodination is slightly different: iodine (I2) is treated wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benzene
Benzene is an Organic compound, organic chemical compound with the Chemical formula#Molecular formula, molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar hexagonal Ring (chemistry), ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen atoms, benzene is classed as a hydrocarbon. Benzene is a natural constituent of petroleum and is one of the elementary petrochemicals. Due to the cyclic continuous pi bonds between the carbon atoms, benzene is classed as an aromatic hydrocarbon. Benzene is a colorless and highly Combustibility and flammability, flammable liquid with a sweet smell, and is partially responsible for the aroma of gasoline. It is used primarily as a Precursor (chemistry), precursor to the manufacture of chemicals with more complex structures, such as ethylbenzene and cumene, of which billions of kilograms are produced annually. Although benzene is a major Chemical industry, industrial che ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Espacenet
Espacenet (formerly stylized as ''esp@cenet'') is a free online service for searching patents and patent applications. Espacenet was developed by the European Patent Office (EPO) together with the member states of the European Patent Organisation. Most member states have an Espacenet service in their national language, and access to the EPO's worldwide database, most of which is in English. In 2022, the Espacenet worldwide service claimed to have records on more than 140 million patent publications. History By launching Espacenet in 1998, the EPO is said to have "revolutionized public access to international patent information, releasing patent data from its paper prisons and changing forever how patents are disseminated, organized, searched, and retrieved." In 2004, i.e. in the early years of Espacenet, Nancy Lambert considered that, although free, Espacenet, like the United States Patent and Trademark Office (USPTO) database of US patents, "still tend dto have primitive sear ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1,3,5-Trichlorobenzene
1,3,5-Trichlorobenzene is an organochlorine compound. It is one of the three isomers of trichlorobenzene. Being more symmetrical than the other isomers, it exists as colourless crystals whereas the other isomers are liquids at room temperature. It is not formed upon chlorination of benzene. Instead it is prepared by the Sandmeyer reaction from 3,5-dichloroaniline. See also *Chlorobenzenes Chlorobenzenes are a group of aryl chlorides/ halobenzenes consisting of one or more chlorine atoms as substituents on a benzene core. They have the formula C6H6–''n''Cl''n'', where ''n'' = 1–6 is the number of chlorine atoms. Depending on the ...—different numbers of chlorine substituents and isomeric forms References {{DEFAULTSORT:Trichlorobenzene, 1,3,5- Chlorobenzenes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Toxicology Program
The National Toxicology Program (NTP) is an inter-agency program run by the United States Department of Health and Human Services to coordinate, evaluate, and report on toxicology within public agencies. The National Toxicology Program is headquartered at the National Institute of Environmental Health Sciences (NIEHS). The NIEHS Director, currently Richard Woychik, also concurrently serves as NTP Director. History The program was established in 1978 by Joseph A. Califano Jr., then the United States Secretary of Health, Education, and Welfare (today known as the Secretary of Health and Human Services). The program arose from congressional concerns about the health effects of chemical agents in the environment. In October 1981, Secretary Richard S. Schwiker granted permanent status to the program. Interagency Center for the Evaluation of Alternative Toxicological Methods The NTP Interagency Center for the Evaluation of Alternative Toxicological Methods (NICEATM) supports the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Journal Of Engineering Research And Science & Technology
International is an adjective (also used as a noun) meaning "between nations". International may also refer to: Music Albums * ''International'' (Kevin Michael album), 2011 * ''International'' (New Order album), 2002 * ''International'' (The Three Degrees album), 1975 *''International'', 2018 album by L'Algérino Songs * The Internationale, the left-wing anthem * "International" (Chase & Status song), 2014 * "International", by Adventures in Stereo from ''Monomania'', 2000 * "International", by Brass Construction from ''Renegades'', 1984 * "International", by Thomas Leer from ''The Scale of Ten'', 1985 * "International", by Kevin Michael from ''International'' (Kevin Michael album), 2011 * "International", by McGuinness Flint from ''McGuinness Flint'', 1970 * "International", by Orchestral Manoeuvres in the Dark from '' Dazzle Ships'', 1983 * "International (Serious)", by Estelle from '' All of Me'', 2012 Politics * Internationalism (politics) * Political international, any ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2,3,7,8-tetrachlorodibenzo-p-dioxin
2,3,7,8-Tetrachlorodibenzo-''p-''dioxin (TCDD) is a polychlorinated dibenzo''-p-''dioxin (sometimes shortened, though inaccurately, to simply ''dioxin'') with the chemical formula CHClO. Pure TCDD is a colorless solid with no distinguishable odor at room temperature. It is usually formed as an unwanted product in burning processes of organic materials or as a side product in organic synthesis. TCDD is the most potent compound ( congener) of its series (polychlorinated dibenzodioxins, known as PCDDs or simply dioxins) and became known as a contaminant in Agent Orange, an herbicide used in the Vietnam War. TCDD was released into the environment in the Seveso disaster. It is a persistent organic pollutant. Biological activity in humans and animals TCDD and dioxin-like compounds act via a specific receptor present in all cells: the aryl hydrocarbon (AH) receptor. This receptor is a transcription factor which is involved in the expression of genes; it has been shown that h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrabromobenzene
1,2,4,5-Tetrabromobenzene is an aryl bromide and a four-substituted Bromobenzenes, bromobenzene with the formula C6H2Br4. It is one of three isomers of tetrabromobenzene. The compound is a white solid. 1,2,4,5-Tetrabromobenzene is an important metabolite of the flame retardant hexabromobenzene. Preparation The synthesis of 1,2,4,5-tetrabromobenzene has already been reported in 1865 from benzene and excess bromine in a sealed tube at 150 °C. However, the clearly reduced melting point of about 160 °C indicates impurities in the final product. In his 1885 dissertation, Adolf Scheufelen published the synthesis of a purer sample using iron(III) chloride FeCl as a Catalysis, catalyst, isolated as "pretty needles" ("schönen Nadeln"). The synthesis can also be carried out in solution in chloroform or tetrachloromethane and yields 1,2,4,5-tetrabromobenzene in 89% yield. This reaction can also be carried out in a laboratory experiment with excess bromine and iron nails ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetraiodobenzene
Tetraiodobenzenes form a group of iodobenzenes with four iodine atoms as substituents (C6H2I4). By their different arrangement, three constitutional isomers are possible. See also *Tetrachlorobenzene Tetrachlorobenzene is any of three isomeric chlorobenzenes with the molecular formula . They differ by the positions of the chlorine atoms around the ring. Tetrachlorobenzenes are colorless crystalline compounds. Properties Synthesis 1,2,4,5-T ... * Tetrabromobenzene References ''Handbook of Data on Common Organic Compounds'', S. 466 (). {{cite journal , doi=10.1021/jo00172a063 , title=Periodination of benzene with periodate/Iodide , date=1983 , last1=Mattern , first1=Daniell Lewis , journal=The Journal of Organic Chemistry , volume=48 , issue=24 , pages=4772–4773 Iodobenzenes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
