{"id":1411,"date":"2018-03-21T15:06:28","date_gmt":"2018-03-21T15:06:28","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/suny-orgbiochemistry\/chapter\/ethers\/"},"modified":"2018-08-08T19:25:31","modified_gmt":"2018-08-08T19:25:31","slug":"ethers","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/suny-orgbiochemistry\/chapter\/ethers\/","title":{"raw":"14.8 Ethers","rendered":"14.8 Ethers"},"content":{"raw":"
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Learning Objectives<\/h3>\r\n
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  1. Describe the structural difference between an alcohol and an ether that affects physical characteristics and reactivity of each.<\/li>\r\n \t
  2. Name simple ethers.<\/li>\r\n \t
  3. Describe the structure and uses of some ethers.<\/li>\r\n<\/ol>\r\n<\/div>\r\nWith the general formula ROR\u2032, an<\/span>\u00a0may be considered a derivative of water in which both hydrogen atoms are replaced by alkyl or aryl groups. It may also be considered a derivative of an alcohol (ROH) in which the hydrogen atom of the OH group is been replaced by a second alkyl or aryl group:<\/span>\r\n\r\n<\/div>\r\n [latex]HOH\\,_{H\\,atoms}^{_{----------------\\rightarrow}^{replace\\,both}}\\,ROR\u2032\\,\\,_{of\\,OH\\,group}^{_{\\leftarrow------------------}^{replace\\,H\\,atom}}\\,ROH[\/latex] <\/span>\r\n

    Simple ethers have simple common names, formed from the names of the groups attached to oxygen atom, followed by the generic name ether<\/em>. For example, CH3<\/sub>\u2013O\u2013CH2<\/sub>CH2<\/sub>CH3<\/sub> is methyl propyl ether. If both groups are the same, the group name should be preceded by the prefix di<\/em>-, as in dimethyl ether (CH3<\/sub>\u2013O\u2013CH3<\/sub>) and diethyl ether CH3<\/sub>CH2<\/sub>\u2013O\u2013CH2<\/sub>CH3<\/sub>.<\/p>\r\n

    Ether molecules have no hydrogen atom on the oxygen atom (that is, no OH group). Therefore there is no intermolecular hydrogen bonding between ether molecules, and ethers therefore have quite low boiling points for a given molar mass. Indeed, ethers have boiling points about the same as those of alkanes of comparable molar mass and much lower than those of the corresponding alcohols (Table 14.4 \"Comparison of Boiling Points of Alkanes, Alcohols, and Ethers\"<\/a>).<\/p>\r\n\r\n

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    Table 14.4<\/span> Comparison of Boiling Points of Alkanes, Alcohols, and Ethers<\/p>\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n
    Condensed Structural Formula<\/th>\r\nName<\/th>\r\nMolar Mass<\/th>\r\nBoiling Point (\u00b0C)<\/th>\r\nIntermolecular Hydrogen Bonding in Pure Liquid?<\/th>\r\n<\/tr>\r\n<\/thead>\r\n
    CH3<\/sub>CH2<\/sub>CH3<\/sub><\/td>\r\npropane<\/td>\r\n44<\/td>\r\n\u201342<\/td>\r\nno<\/td>\r\n<\/tr>\r\n
    CH3<\/sub>OCH3<\/sub><\/td>\r\ndimethyl ether<\/td>\r\n46<\/td>\r\n\u201325<\/td>\r\nno<\/td>\r\n<\/tr>\r\n
    CH3<\/sub>CH2<\/sub>OH<\/td>\r\nethyl alcohol<\/td>\r\n46<\/td>\r\n78<\/td>\r\nyes<\/td>\r\n<\/tr>\r\n
    CH3<\/sub>CH2<\/sub>CH2<\/sub>CH2<\/sub>CH3<\/sub><\/td>\r\npentane<\/td>\r\n72<\/td>\r\n36<\/td>\r\nno<\/td>\r\n<\/tr>\r\n
    CH3<\/sub>CH2<\/sub>OCH2<\/sub>CH3<\/sub><\/td>\r\ndiethyl ether<\/td>\r\n74<\/td>\r\n35<\/td>\r\nno<\/td>\r\n<\/tr>\r\n
    CH3<\/sub>CH2<\/sub>CH2<\/sub>CH2<\/sub>OH<\/td>\r\nbutyl alcohol<\/td>\r\n74<\/td>\r\n117<\/td>\r\nyes<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n<\/div>\r\n

    Ether molecules do have an oxygen atom, however, and engage in hydrogen bonding with water molecules. Consequently, an ether has about the same solubility in water as the alcohol that is isomeric with it. For example, dimethyl ether and ethanol (both having the molecular formula C2<\/sub>H6<\/sub>O) are completely soluble in water, whereas diethyl ether and 1-butanol (both C4<\/sub>H10<\/sub>O) are barely soluble in water (8 g\/100 mL of water).<\/p>\r\n\r\n

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    Example 5<\/h3>\r\n

    What is the common name for each ether?<\/p>\r\n\r\n

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    1. CH3<\/sub>CH2<\/sub>CH2<\/sub>OCH2<\/sub>CH2<\/sub>CH3<\/sub><\/li>\r\n \t
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      Solution<\/p>\r\n\r\n

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      1. The carbon groups on either side of the oxygen atom are propyl (CH3<\/sub>CH2<\/sub>CH2<\/sub>) groups, so the compound is dipropyl ether.<\/li>\r\n \t
      2. The three-carbon group is attached by the middle carbon atom, so it is an isopropyl group. The one-carbon group is a methyl group. The compound is isopropyl methyl ether.<\/li>\r\n<\/ol>\r\n<\/div>\r\n
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        Skill-Building Exercise<\/h3>\r\n

        What is the common name for each ether?<\/p>\r\n\r\n

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        1. \r\n
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          CH3<\/sub>CH2<\/sub>CH2<\/sub>CH2<\/sub>OCH2<\/sub>CH2<\/sub>CH2<\/sub>CH3<\/sub><\/p>\r\n\r\n<\/div><\/li>\r\n \t

        2. \r\n
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          \"image\"<\/div>\r\n<\/div><\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n
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          To Your Health: Ethers as General Anesthetics<\/h3>\r\n

          A general anesthetic<\/em> acts on the brain to produce unconsciousness and a general insensitivity to feeling or pain. Diethyl ether (CH3<\/sub>CH2<\/sub>OCH2<\/sub>CH3<\/sub>) was the first general anesthetic to be used.<\/p>\r\n\r\n

          \r\n\r\n[caption id=\"\" align=\"alignnone\" width=\"812\"]\"image\" William Morton, a Boston dentist, introduced diethyl ether into surgical practice in 1846. This painting shows an operation in Boston in 1846 in which diethyl ether was used as an anesthetic. Inhalation of ether vapor produces unconsciousness by depressing the activity of the central nervous system.\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 Source: Painting of William Morton by Ernest Board, from http:\/\/commons.wikimedia.org\/wiki\/File:Morton_Ether_1846.jpg.<\/em>[\/caption]\r\n\r\n
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          Diethyl ether is relatively safe because there is a fairly wide gap between the dose that produces an effective level of anesthesia and the lethal dose. However, because it is highly flammable and has the added disadvantage of causing nausea, it has been replaced by newer inhalant anesthetics, including the fluorine-containing compounds halothane, enflurane, and isoflurane. Unfortunately, the safety of these compounds for operating room personnel has been questioned. For example, female operating room workers exposed to halothane suffer a higher rate of miscarriages than women in the general population.<\/p>\r\n\r\n

          \r\n\r\n[caption id=\"\" align=\"alignnone\" width=\"1499\"]\"image\" These three modern, inhalant, halogen-containing, anesthetic compounds are less flammable than diethyl ether.<\/em>[\/caption]\r\n

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          Concept Review Exercises<\/h3>\r\n<\/div>\r\n
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            Why does diethyl ether (CH3<\/sub>CH2<\/sub>OCH2<\/sub>CH3<\/sub>) have a much lower boiling point than 1-butanol (CH3<\/sub>CH2<\/sub>CH2<\/sub>CH2<\/sub>OH)?<\/p>\r\n\r\n<\/div><\/li>\r\n \t

          2. \r\n
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            Which is more soluble in water\u2014ethyl methyl ether (CH3<\/sub>CH2<\/sub>OCH3<\/sub>) or 1-butanol (CH3<\/sub>CH2<\/sub>CH2<\/sub>CH2<\/sub>OH)? Explain.<\/p>\r\n\r\n<\/div><\/li>\r\n<\/ol>\r\n<\/div>\r\n[reveal-answer q=\"298977\"]Show Answer[\/reveal-answer]\r\n[hidden-answer a=\"298977\"]\r\n

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            1. Diethyl ether has no intermolecular hydrogen bonding because there is no OH group; 1-butanol has an OH and engages in intermolecular hydrogen bonding.<\/li>\r\n \t
            2. Ethyl methyl ether (three carbon atoms, one oxygen atom) is more soluble in water than 1-butanol (four carbon atoms, one oxygen atom), even though both can engage in hydrogen bonding with water.[\/hidden-answer]<\/li>\r\n<\/ol>\r\n<\/div>\r\n
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              Key Takeaways<\/h3>\r\n
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