{"id":1197,"date":"2018-03-21T14:41:25","date_gmt":"2018-03-21T14:41:25","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/suny-orgbiochemistry\/chapter\/alkynes\/"},"modified":"2018-10-30T14:50:16","modified_gmt":"2018-10-30T14:50:16","slug":"alkynes","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/suny-monroecc-orgbiochemistry\/chapter\/alkynes\/","title":{"raw":"13.6 Alkynes","rendered":"13.6 Alkynes"},"content":{"raw":"
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Learning Objectives<\/h3>\r\n
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  1. Describe the general physical and chemical properties of alkynes.<\/li>\r\n \t
  2. Name alkynes given formulas and write formulas for alkynes given names.<\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n

    The simplest alkyne\u2014a hydrocarbon with carbon-to-carbon triple bond\u2014has the molecular formula C2<\/sub>H2<\/sub> and is known by its common name\u2014acetylene (Figure 13.5 \"Ball-and-Spring Model of Acetylene\"<\/a>). Its structure is H\u2013C\u2261C\u2013H.<\/p>\r\n\r\n

    \r\n\r\n[caption id=\"\" align=\"aligncenter\" width=\"1545\"]\"image\" Figure 13.5 Ball-and-Spring Model of Acetylene.\u00a0Acetylene (ethyne) is the simplest member of the alkyne family.[\/caption]\r\n

    Note<\/span><\/p>\r\n\r\n<\/div>\r\n

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    Acetylene is used in oxyacetylene torches for cutting and welding metals. The flame from such a torch can be very hot. Most acetylene, however, is converted to chemical intermediates that are used to make vinyl and acrylic plastics, fibers, resins, and a variety of other products.<\/p>\r\n\r\n<\/div>\r\n

    Alkynes are similar to alkenes in both physical and chemical properties. For example, alkynes undergo many of the typical addition reactions of alkenes. The International Union of Pure and Applied Chemistry (IUPAC) names for alkynes parallel those of alkenes, except that the family ending is -yne<\/em> rather than -ene<\/em>. The IUPAC name for acetylene is ethyne. The names of other alkynes are illustrated in the following exercises.<\/p>\r\n\r\n

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    Concept Review Exercises<\/h3>\r\n
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      Briefly identify the important differences between an alkene and an alkyne. How are they similar?<\/p>\r\n\r\n<\/div><\/li>\r\n \t

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      The alkene (CH3<\/sub>)2<\/sub>CHCH2<\/sub>CH=CH2<\/sub> is named 4-methyl-1-pentene. What is the name of (CH3<\/sub>)2<\/sub>CHCH2<\/sub>C\u2261CH?<\/p>\r\n\r\n<\/div><\/li>\r\n \t

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      Do alkynes show cis-trans isomerism? Explain.<\/p>\r\n\r\n<\/div><\/li>\r\n<\/ol>\r\n<\/div>\r\n

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      [reveal-answer q=\"724386\"]Show Answer[\/reveal-answer]\r\n[hidden-answer a=\"724386\"]<\/p>\r\n\r\n

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      1. Alkenes have double bonds; alkynes have triple bonds. Both undergo addition reactions.<\/li>\r\n \t
      2. 4-methyl-1-pentyne<\/li>\r\n \t
      3. No; a triply bonded carbon atom can form only one other bond. It would have to have two groups attached to show cis-trans isomerism [\/hidden-answer]<\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n
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        Key Takeaway<\/h3>\r\n