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Ketones

Ketones . Eden Ambrose Emily Deignan Meagan Clark. Definition of a Ketone. A KETONE IS…An organic compound characterized by the presence of a carbonyl group bonded to two carbon atoms in the middle of the carbon chain. . Structure.

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Ketones

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  1. Ketones Eden Ambrose Emily Deignan Meagan Clark

  2. Definition of a Ketone A KETONE IS…An organic compound characterized by the presence of a carbonyl group bonded to two carbon atoms in the middle of the carbon chain.

  3. Structure Ketones and aldehydes are extremely similar, except for the fact that the carbonyl group is in the middle of the chain in a ketone. In an aldehyde the carbonyl group is on the end of the carbon chain. The carbonyl group consists of an oxygen atom bonded to a carbon atom with double bonds. Ketones can be parts of aromatics and rings, they are not always in chains. Acetanone 4-Ethyl-3-pentanone Propanone

  4. Basic Nomenclature • First you need to find the longest carbon chain to find the alkane that is being used. • Ketones are named by taking away the –e ending from the alkane that is being used and adding the ending –one. • When the carbon chain has 5 or more carbons you must add the number in which the oxygen is off of. • You must number your carbon chain from the end that will give you the carbonyl group. 2-Pentanone 4-methylButanone Propanone (Acetone)

  5. Examples of Nomenclature Name the Ketone 2,6-dimethyl-4-Heptanone 2-Heptanone 2-Hexanone

  6. Examples of Nomenclature Butanone 5-methyl-2-Hexanone 4-methyl-2-Pentanone

  7. Properties of Aldehydes and Ketones C=O is a polar molecule due to the four shared electrons in the double C=O bond C=O cannot hydrogen bond together but can accept hydrogen bonds from donors, ex. HOH (water) As a result, Aldehydes and Ketones have higher melting and boiling points than analogous alkanes, but lower boiling points than analogous alcohols. Also ketones are more soluble than alkanes but less soluble than alcohols in aqueous solutes, due to the fact they do not contain OH groups and therefore cannot hydrogen bond

  8. Properties As a result, Aldehydes and Ketones have higher melting and boiling points than analogous alkanes, but lower boiling points than analogous alcohols. Table 1: Boiling Points of Analogous Compounds

  9. Properties Also Ketones are more soluble than alkanes because they are polar molecules Ketones are less soluble than alcohols in aqueous solutes, due to the fact they do not contain OH groups and therefore cannot hydrogen bond

  10. Uses 2-heptanone is a compound that ants use to warn off danger Pheromones are more complex ketones that are used by many insects to enhance hormones [Ex: 9-ketodecenoic acid is used by honeybee queens to take flights] Anti-inflammatory agents such as cortisone Some steroids are also ketones Parts of many hormones such as testosterone and progesterone

  11. Oxidation Reactions An oxidation reaction is a chemical transformation involving a loss of electrons; used in organic chemistry involving the addition of oxygen atoms or the loss of hydrogen atoms • These processes are always accompanied by a reaction partner that undergoes, “reduction,” or gaining electrons during oxidation.

  12. Ketones can be prepared by the controlled oxidation of alcohols. Alcohols burned in oxygen undergo complete oxidation, in which the only products formed are carbon dioxide and water Oxidation reactions can be controlled to form other products and in these reactions oxygen atoms are supplied by oxidizing agents ex. Hydrogen peroxide- H2O2 • The reactive O atoms removes two H atoms from an OH group in the alcohol, and one from the adjacent C atom, resulting in a C=O group, a water molecule is an additional product

  13. Oxidation of Primary, Secondary and Tertiary Alcohols When a secondary alcohol is oxidized, the carbonyl group formed is necessarily attached to two alkyl groups forming a ketone Secondary Alcohol Oxidation Tertiary Alcohol Oxidation Primary Alcohol Oxidation When a primary alcohol is oxidized, an H atom remains bonded to the C atom and an aldehyde is produced Tertiary alcohols cannot undergo this type of oxidation because no H atom is available on the central C atom

  14. Hydrogenation Reactions of Ketones to Alcohols C=O double bond in carbonyl groups can undergo addition reactions with hydrogen The presence if high temperature, pressures and a catalyst are required for this reaction H atoms are added to the carbonyl groups and OH group results- producing an alcohol. This is essentially a reversal of an oxidation reaction Ketones will always produce secondary alcohols

  15. References “Aldehydes and Ketones." Chapter 17: Aldehydes and Ketones. Nucleophilic Addition to C=O. The McGraw Hill Companies, 2000. Web. 27 Sept. 2011. <http://www.mhhe.com/physsci/chemistry/carey/student/olc/ch17aldehydeskeytones.html>. Ball, David W. "The Basics of General, Organic and Biological Chemistry." Welcome | Flat World Knowledge. Web. 27 Sept. 2011. <http://www.flatworldknowledge.com>. "Organic Chemistry." UCLA Chemistry and Biochemistry. UC Regents. Web. 27 Sept. 2011. <http://www.chem.ucla.edu>. Shrestha, Binod. "Unit 12: Aldehydes and Ketones." Learners' Chemistry. Web. 27 Sept. 2011. <http://www.chem-guide.blogspot.com>. Van, Kessel Hans. "Aldehydes and Ketones." Nelson Chemistry 12. Toronto: Thomson Nelson, 2003. Print.

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