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xylene
xylene or dimethylbenzene , C 6 H 4 (CH 3 ) 2 , colorless, oily, liquid aromatic hydrocarbon , used extensively as a solvent, obtained from coal tar, wood tar, and sometimes from petroleum. It is a mixture of three isomers that differ structurally from one another in the location of the two methyl groups that have replaced hydrogen atoms in the benzene molecule. Ortho -xylene is 1,2-dimethylbenzene; it melts at -25°C and boils at 144°C. Meta -xylene is 1,3-dimethylbenzene; it melts at -48°C and boils at 139°C. Para -xylene is 1,4-dimethylbenzene; it melts at 13°C and boils at 138°C. The separation of these three isomers from one another by fractional distillation is difficult because their boiling points are so close together. The ortho and para isomers are converted to meta -xylene by treatment with aluminum trichloride and hydrochloric acid at about 80°C. The xylenes are often used in the synthesis of other compounds, e.g., the xylidenes that are amino derivatives used in the synthesis of azo dyes and other compounds. |
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"xylene." The Columbia Encyclopedia, 6th ed.. 2008. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "xylene." The Columbia Encyclopedia, 6th ed.. 2008. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1E1-xylene.html "xylene." The Columbia Encyclopedia, 6th ed.. 2008. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1E1-xylene.html |
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xylene
xylene (C6H4(CH3)2) Organic chemical compound obtained from the distillates of coal tar and petroleum, and important as a solvent. Chemically it is dimethyl benzene which exists in three isomeric forms: ortho-, meta-, and para-xylene. The isomers have different physical properties.
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"xylene." World Encyclopedia. 2005. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "xylene." World Encyclopedia. 2005. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O142-xylene.html "xylene." World Encyclopedia. 2005. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O142-xylene.html |
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xylene
xy·lene / ˈzīˌlēn/ • n. Chem. a volatile liquid hydrocarbon, C6H4(CH3)2, obtained by distilling wood, coal tar, or petroleum, and used in fuels and solvents, and in chemical synthesis. |
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"xylene." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "xylene." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O999-xylene.html "xylene." The Oxford Pocket Dictionary of Current English. 2009. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O999-xylene.html |
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xylene
xylene (dimethylbenzene) (zy-leen) n. a liquid used for increasing the transparency of tissues prepared for microscopic examination after they have been dehydrated.
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"xylene." A Dictionary of Nursing. 2008. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "xylene." A Dictionary of Nursing. 2008. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O62-xylene.html "xylene." A Dictionary of Nursing. 2008. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O62-xylene.html |
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xylenes
xylenes See dimethylbenzenes.
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"xylenes." A Dictionary of Biology. 2004. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "xylenes." A Dictionary of Biology. 2004. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O6-xylenes.html "xylenes." A Dictionary of Biology. 2004. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O6-xylenes.html |
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