1 / 35

Ch. 11: Unsaturated Hydrocarbons

Ch. 11: Unsaturated Hydrocarbons. Chem 20 El Camino College. Unsaturated Hydrocarbons. Unsaturated means that the molecule contains one or more multiple bonds Alkenes contain a double bond Alkynes contain a triple bond. Label as alkane, alkene, or alkyne. alkane. alkene. alkene. alkyne.

orsin
Télécharger la présentation

Ch. 11: Unsaturated Hydrocarbons

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Ch. 11: Unsaturated Hydrocarbons Chem 20 El Camino College

  2. Unsaturated Hydrocarbons • Unsaturated means that the molecule contains one or more multiple bonds • Alkenes contain a double bond • Alkynes contain a triple bond

  3. Label as alkane, alkene, or alkyne alkane alkene alkene alkyne

  4. Naming • Name the longest carbon chain that contains the multiple bond (-ene or –yne) • Number the chain to give the multiple bond the lowest number, show location • Give the location and name of each substituent in alphabetical order, using numbers, hyphens, and commas between numbers • Give location of the double bond (if needed)

  5. Name These propene 2-butene 1-butene 2-butyne

  6. Name These 2-methylpropene 4,4-dibromo-1-butyne 3-bromo-3-chloro-1-butene

  7. Draw These 1-chloro-1,2,2-trifluoroethene 1,2-dimethyl-1-cyclohexene 1,1,4,4-tetrabromo-2-pentyne

  8. Cis-Trans Isomers • cis--on the same side of the double bond • trans--on opposite sides of the double bond • The cis and trans isomers are different molecules and have different properties • cis-2-butene bp = 3.7 oC • trans-2-butene bp = 0.3 oC

  9. Cis-Trans Isomers • The groups that are cis and trans may differ • cis & trans do not refer to gps on the same C • The words cis and trans come first in the names, followed by a hyphen

  10. Write the names 1-pentene 4-chloro-1-pentene trans-3-heptene cis-1-bromo-1-butene

  11. Write the names cis-3,4-dibromo-3-hexene trans-3,4-dibromo-3-hexene trans-4,4,6,6-tetrabromo-2-hexene

  12. Addition Reactions • In addition reactions of alkenes, the double bond breaks and two atoms add to the molecule • We’ll study some addition reactions • Addition of H2 (hydrogenation) • Addition of X2 (halogenation) • Addition of H2O (hydration)

  13. Hydrogenation • In hydrogenation reactions of alkenes, the double bond breaks & 2 H atoms add • A catalyst such as Pt, Ni, or Pd speeds up the reactions • A cmpd with a multiple bond is unsaturated • A cmpd with single bonds only is saturated

  14. Hydrogenation • Double bonds react with 1 molecule of H2 • Triple bonds react with 2 molecules of H2

  15. Write Product, Name Reactant & Product cyclopentene cyclopentane trans-4-methyl-2-pentene 2-methylpentane

  16. Halogenation Double bond reacts with 1 molecule of bromine Addition of bromine is useful for detection of carbon-carbon double bond

  17. Bromination One cyclohexene molecule reacts with 1 molecule of bromine to give 1,2-dibromo cyclohexane Rapid decolorization of a bromine solution is characteristic of compound containing carbon-carbon double bond

  18. Hydration • In hydration reaction of alkene, the double bond breaks, H and OH add with formation of an alcohol • An acid catalyst (shown as H+) is used • If the two “C”s of the double bond are attached to different groups, H adds to the carbon of the double bond with more “H”s.

  19. Hydration

  20. Write Product, Name Reactant, C6H12O cyclohexene C5H12O 2-methyl-2-butene

  21. 3-D (Spatial) Drawings • Bonds lying on the plane of the paper are shown with ordinary lines • Bonds coming out of the page are shown as solid wedges • Bonds going to the back of the page are shown as dashed (striped, broken)wedges

  22. 3-D (Spatial) Drawings • Note--every tetrahedral will have two lines, one broken wedge(dash), and one solid wedge. The lines make the zig-zag chain.

  23. 3-D (Spatial) Drawings • Draw a spatial drawing for butane • Draw a spatial drawing for 2,2-dibromopropane

  24. 3-D (Spatial) Drawings • Do not show planar atoms with dashes or wedges • Draw a spatial drawing for trans-1-bromo-1-propene

  25. Aromatic Hydrocarbon • Benzene molecule, C6 H6 , consists of a ring of six carbon atoms with one hydrogen atom attached to each carbon. • Each carbon atom uses three valence electrons to bond to hydrogen atom and two adjacent C atoms • Six electrons are shared equally among six carbon atoms

  26. Naming of Aromatic Hydrocarbon • When benzene has only one substituent the benzene ring is not numbered. • Example Chlorobenzene • When there are 2 or more substituents the benzene ring is numbered to give the lower numbers to the substituents. • Example 1,3-dichlorobenzene

  27. Common name of Aromatic Compounds

  28. Naming of Aromatic Hydrocarbon • When a common name such as toluene, phenol or aniline is used, the carbon atom attached to the methyl, hydroxyl, or amine group is number as carbon 1 • Example: 2-chlorotoluene • Example: 4-ethyltoluene

  29. Polycyclic Aromatic Compounds (PAHs)

  30. Polymer • Polymer are large molecules that consist of small units called monomers • Many are made by addition reaction of alkenes. Examples: • Polyethylene monomer is ethylene • Polyvinyl chloride monomer is vinyl chloride

More Related