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00:25 Aug 6, 2005 |
English language (monolingual) [PRO] Tech/Engineering - Chemistry; Chem Sci/Eng | |||||||
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| Selected response from: Coral Getino United States | ||||||
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SUMMARY OF ALL EXPLANATIONS PROVIDED | ||||
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4 | definitions: |
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4 | one R1, three groups |
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3 | definitions below |
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Discussion entries: 1 | |
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definitions below Explanation: From the McGraw-Hill Dictionary of Scientific and Technical Terms: aromatic: 1. Pertaining to or characterized by the presence of at least one benzene ring. 2. Describing those compounds having physical and chemical properties resembling those of benzene. aryl: an organic group derived from an aromatic hydrocarbon by removal of one hydrogen. aryl compound: molecules with the six-carbon aromatic ring structure characteristic of benzene compounds derived from aromatics. Alkaryl produces 4020 Google hits but no definitions. The above dictionary has no definition of it either, but it does have the following which may possibly be relevant: Alkar process. Catalytic alkylation of aromatic hydrocarbons with olefins to produce alkylaromatics: for example, production of ethyl benzene from benzene and ethylene. |
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definitions: Explanation: aromatic compound Related: Organic Chemistry any of a large class of compounds that includes benzene and compounds that resemble benzene in certain of their chemical properties. Originally applied to a small class of pleasant-smelling chemicals derived from vegetables, it now encompasses a wide diversity of compounds with no connection to the sense of smell. Common aromatic compounds other than benzene include toluene, naphthalene, and anthracene (all of which are present in coal tar). Each of these compounds contains at least one ring that consists of six carbon atoms, each joined to at least two other carbon atoms, and each joined to adjacent carbon atoms by one single and one double bond. The resulting hexagonal structure is characteristic of many aromatic compounds. The general rule is that aromatic molecules have 4 n + 2 delocalized electrons (where n is an integral number). Thus the number of delocalized electrons in benzene (6), naphthalene (10), and anthracene (14) agree with their aromatic character. On the other hand, the eight-membered cyclic compound with four alternating double bonds (cyclooctatetraene) is not aromatic and shows reactivity similar to alkenes . For this reason, the bonds in the aromatic ring are less reactive than ordinary double bonds; aromatic compounds tend to undergo ionic substitution (e.g., replacement of a hydrogen bonded to the ring with some other group) rather than addition (which would involve breaking one of the resonant bonds in the ring). Presence of the six-membered benzene ring is not essential for aromatic compounds; for example, furan, a heterocyclic compound that has a five-membered ring that includes an oxygen atom, has aromatic properties, as does pyridine, a heterocyclic compound whose six-membered ring includes a nitrogen atom. aryl group Related: Organic Chemistry (âr´Ĭl) , in chemistry, group of atoms derived from benzene or from a benzene derivative by removing one hydrogen that is bonded to the benzene ring (see radical ). The simplest aryl group is phenyl, C 6 H 5 ; it is derived from benzene. The tolyl group, CH 3 C 6 H 4 , is derived from toluene (methylbenzene). The xylyl group, (CH 3 ) 2 C 6 H 3 , is derived from xylene (dimethylbenzene). Just as several different alkyl groups may be derived from certain alkanes, so may several aryl groups be derived from certain aromatic compounds; for example, three different tolyl groups can be formed from toluene by removing hydrogen from different locations relative to the methyl group. When a functional group is joined with an aryl group, replacing the hydrogen that had been removed, a compound is formed whose characteristics depend largely on the functional group. ****From the patent description below: [0169] "Aryl" refers to an unsaturated aromatic carbocyclic group of from 6 to 14 carbon atoms having a single ring (e.g., phenyl) or multiple condensed rings (e.g., naphthyl or anthryl). Preferred aryls include phenyl, naphthyl and the like. [0154] "Alkaryl" refers to -alkylene-aryl groups preferably having from 1 to 10 carbon atoms in the alkylene moiety and from 6 to 10 carbon atoms in the aryl moiety. Such alkaryl groups are exemplified by benzyl, phenethyl and the like. [0153] "Alkylene" refers to divalent alkylene groups preferably having from 1 to 10 carbon atoms and more preferably 1 to 6 carbon atoms. This term is exemplified by groups such as methylene (--CH.sub.2--), ethylene (--CH.sub.2CH.sub.2--), the propylene isomers (e.g., --CH.sub.2CH.sub.2CH.sub.2-- and --CH(CH.sub.3)CH.sub.2--) and the like. Reference: http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=... |
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one R1, three groups Explanation: Hi, Jianming. In this sentence, they are talking about R1 (a part added to a more basic molecule to form a different compound). Here they call it a "group". This part doesn't always have to be the same; it can be changed to obtain a different compound. In this case, it could be an aromatic "group", an aryl "group" or an "alkaryl" group (all of them chemically different things). By the way, are you sure it's "groups" and not "group" in "aryl or alkaryl groups having from about 12..."?. Hope this helps! |
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