1 / 181

Organic Nomenclature

Organic Nomenclature. Organic Compounds. Organic Compounds - any covalently bonded compound containing carbon (except carbonates and oxides). Organic Compounds. Contain carbon Have covalent bonds Have low melting points Have low boiling points Burn in air (oxygen)

ssinger
Download Presentation

Organic Nomenclature

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. Organic Nomenclature

  2. Organic Compounds • Organic Compounds - any covalently bonded compound containing carbon (except carbonates and oxides)

  3. Organic Compounds • Contain carbon • Have covalent bonds • Have low melting points • Have low boiling points • Burn in air (oxygen) • Are soluble in nonpolar solvents • Form large molecules

  4. General Characteristics of Organic Molecules • Organic molecules exhibit three different types of hybridization at the carbon center: • sp3 hybridized carbons for tetrahedral geometries; • sp2hybridized carbons for trigonal planar geometries; and • sp hybridized carbons for linear geometries.

  5. Stabilities of Organic Molecules • Carbon forms very strong bonds between H, O, N, and halogens. • Carbon also forms strong bonds with itself. • Therefore, C can form stable long chain or ring structures. • Bond strength increases from single to double to triple bond. • Bond length decreases in the same direction.

  6. Hydrocarbons • Hydrocarbons- Organic compounds that contain only carbon & hydrogen • Alkanes- contain only single covalent bonds • Alkenes- contain one or more carbon - carbon double bond • Alkynes- contain one or more carbon-carbon triple bond

  7. Saturated & Unsaturated Hydrocarbons • Saturated hydrocarbons – contain only single carbon-carbon bonds (alkanes) • Unsaturated hydrocarbons – contain double carbon-carbon bonds (alkenes) or triple carbon-carbon (alkynes) bonds

  8. Formulas • Alkanes = CnH2n+2 • Alkenes = CnH2n • Alkynes = CnH2n-2

  9. Nomenclature • Must memorize prefixes • To name, look at the formula for the hydrocarbon • Determine if it is an alkane, alkene, or alkyne • Use the prefix for the number of carbons • Add ending (ane, ene, yne)

  10. Example • Name C3H8 • This falls under the equation CnH2n+2 • Therefore it is an alkane • Since n=3 we will use the prefix prop • Since it is an alkane we will use the ending ane • propane

  11. Alkanes • Contain C and H only • Contain single bonds C-C • Have 4 bonds to every carbon (C) atom • Are nonpolar

  12. Complete Structural Formulas Show the bonds between each of the atoms H H   H  C  H H C H   H H CH4 , methane

  13. Drawing structures: it’s all good 2-butene On a test, choose a method that shows all Hs This is called the “condensed structure” CH3CH=CHCH3 Using brackets can also shorten some formulas: CH3(CH2)4CH3 vs. CH3CH2CH2CH2CH2CH3

  14. More Alkanes H H Condensed Structural Formulas H C C H CH3 CH3 H H Ethane H H H H C C C H CH3 CH2 CH3 H H H Propane

  15. IUPAC Names Name # carbons Structural Formula Methane 1 CH4 Ethane 2 CH3CH3 Propane 3 CH3CH2CH3 Butane 4 CH3CH2CH2CH3 Pentane 5 CH3CH2CH2CH2CH3

  16. Formic acid Acetone Acetylene Naming: common vs. IUPAC • Common names used in the 1800’s are still used for some compounds today: • The International Union of Pure and Applied Chemistry (IUPAC) was established in 1900s • Frequent revisions to nomenclature • Systematic method allows an infinite number of compounds to be named given a few rules

  17. IUPAC NAMES Name # carbons Structural Formula Hexane 6 CH3CH2CH2CH2CH2CH3 Heptane 7 CH3CH2CH2CH2CH2CH2CH3 Octane 8 CH3CH2CH2CH2CH2CH2CH2CH3 Nonane 9 CH3 CH2 CH2CH2CH2CH2CH2CH2CH3 Decane 10 CH3CH2CH2CH2CH2CH2CH2CH2CH2CH3

  18. Learning Check Alk1 A. What is the condensed formula for H H H H H C C C C H H H H H B. What is its molecular formula? C. What is its name?

  19. Solution Alk1 A. CH3CH2CH2CH3 B. C4H10 C. butane

  20. Example • Name C5H12 • 5 carbons = pent • CnH2n+2 = alkane (ane) • pentane

  21. Alkenes and Alkynes • Alkenes are hydrocarbons with at least one double carbon to carbon bond. • To show the presence of the double bond, the –ane suffix from the alkane name is changed to –ene. • The alkenes are unsaturated with respect to hydrogen • This means it does not have the maximum number of hydrogen atoms as it would if it were an alkane (a saturated hydrocarbon).

  22. Naming is similar to naming alkanes except: • The longest continuous chain must contain the double bond. • The base name now ends in –ene. • The carbons are numbered so as to keep the number for the double bond as low as possible. • The base name is given a number which identifies the location of the double bond. • An alkyne is a hydrocarbon with at least one carbon to carbon triple bond. • Naming an alkyne is similar to the alkenes, except the base name ends in –yne.

  23. Alkenes • Carbon-carbon double bonds • Names end in -ene H2C=CH2 ethene (ethylene) H2C=CH-CH3 propene (propylene) cyclohexene

  24. Alkynes • Carbon-carbon triple bonds • Names end in -yne HCCH ethyne(acetylene) HCC-CH3 propyne

  25. Naming Alkenes and Alkynes When the carbon chain has 4 or more C atoms, number the chain to give the lowest number to the double or triple bond. 1 2 3 4 CH2=CHCH2CH3 1-butene CH3CH=CHCH3 2-butene CH3CHCHCH3 2-butyne

  26. C2H4 Numbering carbons 1-pentene Q- draw pentene A- Where’s the bond? We number C atoms • Thus, naming compounds with multiple bonds is more complex than previously indicated • Only if 2+ possibilities exist, are #s needed • Always give double bond the lowest number • Q - Name these 2-butene Ethene 3-nonyne

  27. CH3CH2CH2CH=C=CH2 Multiple multiple bonds 2,3-heptadiene • Give 1st bond (1st point of difference) lowest # • include di, tri, tetra, penta, etc. before ene/yne • Comma between #s, hyphen between #-letter • You do not need to know ene + yne 2,4,6-nonatriyne 2-butyne 1,2,4-pentatriene 1,2-hexadiene

  28. Cyclic structures • Cyclic structures are circular • Have “cyclo” in name • Benzene is not a cyclic structure • cyclopentane Q- Draw these (note: carbons in a double bond should be consecutive- 1 and 2, 5 and 6, etc.): cyclobutene 1,3-cyclopentadiene cyclopropane

  29. C H 3 H C C H 3 3 C H 3 Naming side chains • Names are made up of: side chains, root • 2,3-dimethylpentane • Root is the longest possible HC chain • Must contain multiple bonds if present • Add -yl to get name of side chain • Common side chains include: • CH3- methyl CH3CH2- ethyl • CH3CH2CH2- propyl (CH3)2CH- isopropyl • “iso” (branched) is not an IUPAC convention • Br- (bromo), Cl- (chloro), F- (fluoro), I- (iodo)

  30. Naming side chains Example: use the rules on the bottom of handout to name the following structure Rule 1: choose the correct ending ene

  31. Naming side chains Rule 2: longest carbon chain ene

  32. Naming side chains Rule 3: attach prefix (according to # of C) 1-hexene ene

  33. Naming side chains Rule 4: Assign numbers to each carbon 1-hexene

  34. Naming side chains Rule 4: Assign numbers to each carbon 1-hexene 1-hexene

  35. Naming side chains ethyl methyl methyl Rule 5: Determine name for side chains 1-hexene 1-hexene

  36. Naming side chains ethyl methyl methyl Rule 6: attach name of branches 2-ethyl-4,4-dimethyl-1-hexene

  37. Learning Check HA3 Write the IUPAC name for each of the following unsaturated compounds: A. CH3CH2CCCH3 CH3 B. CH3C=CHCH3 C.

  38. Solutions HA3 Write the IUPAC name for each of the following unsaturated compounds: A. CH3CH2CH=CHCH3 2-pentyne CH3 B. CH3C=CHCH3 C. 2-methyl-2-butene 3-methylcyclopentene

  39. Alkyl Groups Branches on carbon chains H H C CH3 methyl H H H H C C CH3CH2 ethyl H H

  40. Branched Alkanes CH3 CH3CHCH3 methyl groups CH3 CH3 CH3CHCH2CHCH3

  41. Naming Branched Alkanes CH3 methyl branch CH3CH2CH2CHCH2CH3 6 5 4 3 2 1 Count

  42. Naming Branched Alkanes CH3 methyl branch CH3CH2CH2CHCH2CH3 6 5 4 3 2 1 Count 3-Methylhexane on third C CH3 six carbon chain group

  43. IUPAC • Carbon chains need to be numbered in order to designate the carbon atom that the substituted group is added. • Follow these guidelines: • Find the longest continuous carbon chain • Number the chain so the substituent's have the lowest possible number. • Give priority to the multiple bonds.

  44. Numbering priority • 1. functional groups • 2. double and triple bonds • 3. substituents

  45. Once all groups have been numbered, place them in alphabetical order in the final compounds name. • Numbers are separated by commas • Names and numbers are separated by dashes. • Use mathematical prefixes for multiple substituent's.

  46. Ex: • CH3CH2CHClCH2CH=CHCHBrCH3 • 2-bromo-6-chloro-3-octene

  47. Learning Check Alk4 A. CH3CH3 CH3CHCH2CHCH3 B. CH3 CH3 CH3CH2CHCH2CCH2CH3 CH3

  48. Solution Alk4 A. CH3CH3 CH3CHCH2CHCH3 2,4-dimethylpentane B. CH3 CH3 CH3CH2CHCH2CCH2CH3 CH3 3,3,5-trimethylheptane

  49. Learning Check Alk5 Write a condensed structure for A. 3,4-dimethylheptane B. 2,2-dimethyloctane

  50. Solution Alk5 A. 3,4-dimethylheptane CH3 CH3CH2CHCHCH2CH2CH3 CH3 • 2,2-dimethyloctane CH3 CH3CCH2CH2CH2CH2CH2CH3 CH3

More Related