Ch. 11: Carbon A Multifarious Element

1. Ch. 11: Carbon A Multifarious Element

2. Why Carbon? • Versatility • Single, double, triple bonds • Structural diversity

3. Short-hand for expressing carbon-based compounds • C4H10: butane • Structural formula • Condensed structural formula • Carbon skeleton formula • C4H8 • C4H6

4. Isomers • Isomers – same composition, diff. structures • Structural isomers: same # atoms, diff. structures Ethanol (C2H6O) vs. dimethylether (C2H6O)

5. Problems • Draw all isomers of C3H8O. There are 3. • Draw all isomers of C4H8Br2. There are 9.

6. Stereoisomers • Same formula, diff. orientation • Two types: • 1) geometric • 2) optical isomers

7. Geometric isomers • Require double bond! • Cis vs. trans

8. Optical isomers • Nonsuperimposable mirror images • Called chiral molecules (chirality) • Pairs of chiral molecules = enantiomers

9. Classes of Carbon-Containing Cmpds • Hydrocarbons • Only C & H • Alkane: CnH2n+2 • (Saturated every C-C bond single) • Alkene: CnH2n (at least one double bond btwn C’s) • (Unsaturated  double, triple bonds)

10. Classes of Carbon-Containing Cmpds • Alkyne: CnH2n-2 (at least one triple bond btwn C’s) • Cyclohydrocarbons: rings of carbon • Aromatic: rings w/pi-bonding • benzene

11. Naming Alkanes • Suffix: -ane • Count out longest carbon chain • Prefixes: • 1C meth- • 2C eth- • 3C prop- • 4C but- • 5C pent- • 6C hex- • 7C hept- • 8C oct- • 9C non- • 10C dec-

12. Naming Alkanes • Hydrocarbon substitution = alkyl groups • Meth  methyl, etc. • Use number, followed by “-”, to designate placement of substituent • 2-methylpentane • If 2 or more of same subs.  di, tri, tetra, etc. • 2,3-dimethylpentane • If more than one different alkyl group, use alphabetic ordering • Butyl precede ethyl precedes methyl • 4-ethyl-3-methylheptane • In naming hydrocarbons always go with longest carbon-chain

13. Draw out the following alkanes and rename them, if needed • Hexane • 2-methylhexane • 2,2-diethylpropane • 4-ethyl-2-methylnonane • Now, I’ll draw some and you name them

14. Naming Alkenes, alkynes • Start counting carbon chain from lowest carbon containing double/triple bond • 1-propene, not 2-propene • Use number, followed by “-”, to designate placement of double or triple bond • 1-butene • 2-octyne

15. Draw the following and if there is isomerism draw both structures and name them • 1-hexene • 2-hexene • 3-heptyne • 2-methyl-3-heptyne • Now, I’ll draw some and you name them

16. Naming Halohydrocarbons • Same rules apply • In alphabetical order • Bromine  bromo • chlorine  chloro • fluorine  fluoro • iodine  iodo • Ex: 2-chlorobutane • Practice (fix if necessary): • 3-bromo-2-chloropentane • 3,3-diiodobutane • Now, I’ll draw some and you name them

17. Naming Aromatic Cmpds • Monosubstitution: • Methylbenzene  toluene • Phenol • Aniline • Disubstitution: • o- = ortho • m- = meta • p- = para

18. Practice • Chlorobenzene (does it make a difference where you put the Cl?) • Draw all isomers (and name them) of a benzene that has 1 bromine and one fluorine • Which combinations are disallowed and why?

19. Other functional groups • Functional group = characteristic grouping or arrangement of atoms • Alcohols = R-OH • Methanol, ethanol, propanol, etc. • Structural isomers of alcohols • 1,2-ethanediol = ethylene glycol

20. Practice: rename if necessary • 1-propanol • 2-propanol • 3-propanol • Now, I’ll draw some and you name them

21. Other functional groups • Ether: ROR’ 1) Select the longest carbon chain and name it as the correct alkane. 2) Change the “-yl” ending of the other (shorter) hydrocarbon group to “-oxy” to obtain the alkoxy group name. 3) Combine the two names giving the alkoxy group name first.

22. Practice • Dimethylether • Butoxyhexane • methoxyethane • Now, I’ll draw some and you name them

23. Other functional groups • Amines • RNH2 • Putrescine = 1,4-butanediamine • Cadaverine = 1,5-pentanediamine

24. Practice • Triethylamine • Triisopropylamine • Now, I’ll draw some and you name them

25. Other functional groups • Aldehydes • RCOH • Start counting the carbon-chain from the C=O • Methanal, butanal, hexanal • Ketones • RCOR’ • Start counting the carbon-chain from the C=O • 2-propanone, 3-heptanone

26. Practice • Methanal • Hexanal • 2-pentanone • 4-decanone • Now, I’ll draw some and you name them

27. Other functional groups • Carboxylic acids • RCOOH • Start counting the carbon-chain from the C=O • Methanoic acid, ethanoic acid, etc. • Esters • RCOOR’ • Start counting the carbon-chain from the C=O • -OR’  takes on alkyl name • RCO  takes on –oate suffix • Thus, HCOOCH3 methyl methanoate • By the way, acetate = ethanoate

28. Practice • Hexanoic acid • 2-methylpropanoic acid (give its other name) • Hexyl ethanoate • Butyl butanoate • 3-methylbutyl ethanoate (has a more common name) • Now, I’ll draw some and you name them

29. Other functional groups • Amides • RCONR2 • Ex: methanamide, ethanamide

30. Polymers • Huge molecules with repeating monomers (subunits) • Thermoplastics (polyethylene, styrofoam): respond to heating • Soften and flow when heated, harden when cooled; reversible • Over 60 million tons of polyethylene produced annually! • Thermosetting plastics (Formica-brand): initially soft, but solid when heated; irreversible

31. Styrofoam, Teflon, silicone, Kevlar

32. Condensation Polymers • Combining monomers and splitting out small molecules (like water) • Demo • Making nylon • Demo • Green “snot”

33. Green “snot”

34. Copolymers • Polymerization of 2 (or more) diff. monomers • Such as: • Styrene-butadiene rubber (SBR) • Predominately used for car and light-truck tires