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Degree of Unsaturation

Degree of Unsaturation. How to determine the number of rings and multiple bonds in a compound from its molecular formula. No hydrocarbon can contain a greater number of hydrogens than fits the formula C n H 2n+2. The number of hydrogens is always even. All such compounds are acyclic.

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Degree of Unsaturation

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  1. Degree of Unsaturation How to determine the number of rings and multiple bonds in a compound from its molecular formula

  2. No hydrocarbon can contain a greater number of hydrogens than fits the formula CnH2n+2 The number of hydrogens is always even. All such compounds are acyclic

  3. CH3CH2CH2CH3 CH3CH(CH3)CH3 They may be straight (normal) chains as in n-butane (C4H10) or they may be branched as in isobutane (C4H10)

  4. If two hydrogen atoms on non-adjacent carbons of n-butane (C4H10) are removed a ring, cyclobutane (C4H8), is formed with the loss of H2 then This process is not necessarily a chemical reaction but rather a conceptual device.

  5. If two hydrogen atoms on adjacent carbons of n-butane (C4H10) are removed a double bond is formed with the loss of H2. then In this case, the alkene, 1-butene (C4H8), is formed.

  6. A compound with the molecular formula C4H8 is either an alkene (olefin) or cycloalkane. How to determine the Degree of Unsaturation (DU) of this compound? C4H10 - C4H8 = H2 divided by 2 = 1 DU most saturated C4 compound

  7. DU Example 4 benzene norbornene naphthalene Try the following formulas: C6H6 C7H10 3 C10H8 7

  8. How is the Degree of Unsaturation of a hydrocarbon containing halogen, or other monovalent atom, determined? Every halogen in a hydrocarbon replaces a hydrogen.

  9. Replace each halogen with hydrogen and then compare this hydrocarbon with the most saturated hydrocarbon. The alkyl halide C8H5BrCl2 becomes C8H8 C8H18 - C8H8 =H10 /2 = 5 DU

  10. Br Cl 1 DU - C6 H H 3 DU 1 DU - C8 H 5 DU H Cl H C8 H5 Br Cl2 One example of an alkyl halide C8H5BrCl2

  11. How is the Degree of Unsaturation of a hydrocarbon containing oxygen, or other divalent atom, determined?

  12. C4H8O C4H8 1DU 1DU Ignore divalent atoms!

  13. carbonyl - 1 DU benzene ring - 4 DU 2,4-Dichlorophenoxyacetic acid

  14. C8H6Cl2 C8H8 (drop O3) (- Cl2 + H2) 2,4-Dichlorophenoxyacetic acid C8H6Cl2O3 C8H18 - C8H8 = H10 / 2 = 5 DU

  15. How is the Degree of Unsaturation of a hydrocarbon containing nitrogen, or other trivalent atom, determined? Substitute CH for every N.

  16. (- N + CH) pyridine benzene C5H5N C6H6 C6H14 - C6H6 = H8 / 2 = 4 DU

  17. 1DU 1DU (5-membered ring) 4DU 1DU (6-membered ring) 1DU Cocaine -C17H21NO4 C18H22 C17H21NO4 C17H21N C18H38 - C18H22 = H16 / 2 = 8 DU

  18. Degree of Unsaturation The End F. E. Ziegler 2003

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