1 / 77

Classes of Hydrocarbons

Classes of Hydrocarbons. Hydrocarbons. Aliphatic. Aromatic. Hydrocarbons. Aliphatic. Aromatic. Alkanes. Alkenes. Alkynes. H. H. H. H. C. C. H. H. Hydrocarbons. Alkanes are hydrocarbons in which all of the bonds are single bonds. Aliphatic. Alkanes. H. H. C. C. H. H.

carrie
Download Presentation

Classes of 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. Classes of Hydrocarbons

  2. Hydrocarbons Aliphatic Aromatic

  3. Hydrocarbons Aliphatic Aromatic Alkanes Alkenes Alkynes

  4. H H H H C C H H Hydrocarbons Alkanes are hydrocarbons in which all of the bonds are single bonds. Aliphatic Alkanes

  5. H H C C H H Hydrocarbons Alkenes are hydrocarbons that contain a carbon-carbon double bond. Aliphatic Alkenes

  6. HC CH Hydrocarbons Alkynes are hydrocarbons that contain a carbon-carbon triple bond. Aliphatic Alkynes

  7. H H H H H H Hydrocarbons The most common aromatic hydrocarbons are those that contain a benzene ring. Aromatic

  8. Reactive Sites in Hydrocarbons The Functional Group Concept

  9. Functional Group a structural unit in a molecule responsible for itscharacteristic chemical behavior and its spectroscopic characteristics

  10. R—H R—X Alkanes functional group is a hydrogen atom the reaction that takes place is termed a substitution one of the hydrogens is substitutedby some other atom or group, X

  11. R—H R—X H H H H Cl H H H C C C C H H H H Alkanes functional group is a hydrogen the reaction that takes place is substitution one of the hydrogens is substituted by some other atom or group + HCl + Cl2

  12. Functional Groups in Hydrocarbons alkanes RH alkenes RH, double bond alkynes RH, triple bond aromatics ArH, double bond

  13. Some Key Functional Groups

  14. Families of organic compounds and their functional groups Alcohols ROH Alkyl halides RX (X = F, Cl, Br, I) Amines primary amine: RNH2 secondary amine: R2NH tertiary amine: R3N Ethers ROR

  15. O O C C Many classes of organic compounds contain a carbonyl group R Carbonyl group Acyl group

  16. O O C C Many classes of organic compounds contain a carbonyl group H R Carbonyl group Aldehyde

  17. O O C C Many classes of organic compounds contain a carbonyl group R' R Carbonyl group Ketone

  18. O O C C Many classes of organic compounds contain a carbonyl group OH R Carbonyl group Carboxylic acid

  19. O O C C Many classes of organic compounds contain a carbonyl group OR' R Ester Carbonyl group

  20. O O C C Many classes of organic compounds contain a carbonyl group NH2 R Amide Carbonyl group

  21. General formula for an alkane CnH2n+2 Introduction to Alkanes: Methane, CH4 Ethane, C2H6 Propane, C3H8

  22. The simplest alkanes Methane (CH4) CH4 Ethane (C2H6) CH3CH3 Propane (C3H8) CH3CH2CH3 bp -160°C bp -89°C bp -42°C No isomers possible for C1, C2, C3 hydrocarbons

  23. Isomeric Alkanes: The Butanes C4H10 General formula for any butane

  24. C4H10 n-Butane Isobutane CH3CH2CH2CH3 (CH3)3CH bp -0.4°C bp -10.2°C

  25. Higher n-Alkanes Pentane (C5H12) and Beyond CnH2n+2 n > 4

  26. CnH2n+2 n > 4 CH3CH2CH2CH2CH3 n-Pentane CH3CH2CH2CH2CH2CH3 n-Hexane CH3CH2CH2CH2CH2CH2CH3 n-Heptane

  27. The C5H12 Isomers

  28. C5H12 (CH3)2CHCH2CH3 CH3CH2CH2CH2CH3 Isopentane n-Pentane (CH3)4C Neopentane

  29. How many isomers? The number of isomeric alkanes increases as the number of carbons increase. There is no simple way to predict how many isomers there are for a particular molecular formula.

  30. Table 2.3 Number of Constitutionally Isomeric Alkanes CH4 1 C2H6 1 C3H8 1 C4H10 2 C5H12 3 C6H14 5 C7H16 9

  31. Table 2.3 Number of Constitutionally Isomeric Alkanes CH4 1 C8H18 18 C2H6 1 C9H20 35 C3H8 1 C10H22 75 C4H10 2 C15H32 4,347 C5H12 3 C20H42 366,319 C6H14 5 C40H82 62,491,178,805,831 C7H16 9

  32. C6H6 Isomers How many isomers with the composition C6H6 can you draw?

  33. C6H6 Isomers: How many isomers with the compositionC6H6 can you draw?

  34. Structure and Bonding in Alkenes

  35. Structure of Ethylene bond angles: H-C-H = 117° H-C-C = 121° bond distances: C—H = 110 pm C=C = 134 pm planar

  36. Bonding in Ethylene Framework of s bonds Each carbon is sp2 hybridized s s s s s

  37. Bonding in Ethylene Each carbon has a half-filled p orbital

  38. Bonding in Ethylene Side-by-side overlap of half-filled p orbitals gives a p bond

  39. Isomerism in Alkenes

  40. Isomers Isomers are different compounds thathave the same molecular formula (composition).

  41. Isomers Constitutional isomers Stereoisomers

  42. Isomers Constitutional isomers Stereoisomers same connectivity; different arrangementof atoms in space different connectivity

  43. Isomers Constitutional isomers Stereoisomers consider the isomeric alkenes of molecular formula C4H8

  44. H3C H CH2CH3 H C C C C H3C H H H H3C CH3 H H3C C C C C H H H CH3 1-Butene 2-Methylpropene trans-2-Butene cis-2-Butene

  45. H3C H CH2CH3 H C C C C H3C H H H H3C CH3 C C H H 1-Butene 2-Methylpropene Constitutional isomers cis-2-Butene

  46. H3C H CH2CH3 H C C C C H3C H H H H H3C C C H CH3 1-Butene 2-Methylpropene Constitutional isomers trans-2-Butene

  47. H3C CH3 H H3C C C C C H H H CH3 Stereoisomers trans-2-Butene cis-2-Butene

  48. Molecular Chirality: Enantiomers

  49. Chirality A molecule is chiral if its two mirror image forms are not superposable upon one another. A molecule is achiral if its two mirror image forms are superposable.

  50. Bromochlorofluoromethane is chiral It cannot be superposed point for point on its mirror image. Cl Br H F

More Related