1. Chemistry 2100
Lecture 2

2. Alkynes and Alkenes alkene (olefins): CnH2n
alkyne (acetylenes): CnH2n-2
Ethene
Ethyne
Ethylene
Acetylene

3. Naming Alkenes and Alkynes
Parent name is that of the longest chain that contains the C=C or C≡C.
Number the chain from the end that gives the lower numbers to the carbons of the C=C or C≡C.
Locate the C=C or C≡C by the number of its first carbon.
Use -ene to show C=C, -yne for C≡C.
For cycloalkenes:
Number ring carbons to give carbon 1 and 2 to the C=C bond.
Because of this convention, no need to specify the number of the C=C.

5. Alkene Isomerism 3-methyl-cis-2-pentene 3-methyl-trans-2-pentene
2-methyl-2-pentene

6. Conjugation

9. 2

11. trans-retinal

12. trans-retinal

13. trans-retinal

14. trans-retinal
11-cis-retinal

16. opsin

17. opsin

18. opsin

19. opsin
rhodopsin

20. rhodopsin
metarhodopsin

21. rhodopsin
metarhodopsin

22. rhodopsin
metarhodopsin

23. rhodopsin
neural
impulse
metarhodopsin

24. neural
impulse
metarhodopsin
11-cis-retinal
trans-retinal

25. neural
impulse
metarhodopsin
11-cis-retinal
trans-retinal

26. neural
impulse
metarhodopsin
11-cis-retinal
trans-retinal

27. neural
impulse
metarhodopsin
11-cis-retinal
trans-retinal
opsin

28. neural
impulse
metarhodopsin
11-cis-retinal
trans-retinal
opsin

29. Terpenes – natural polyenes
limonene
(orange, dill)
myrcene
(bay)
geraniol
(rose)
menthol
(mint)
carvone
(spearmint, dill)
zingiberene
(ginger)
-selinene
(celery)
caryophyllene
(cloves)

30. squalene

31. squalene
~25 steps
lanosterol
cholesterol

32. Making Alkenes
tetra tri di mono

33. Reactions of Alkenes
Hydrogenation
(cis or trans)

34. Partially Hydrogenated Vegetable Oil•

35. Halogenation
CH2Cl2 RT
∆ / h
Cl2
CH2Cl2

36. Acid Addition
CH2Cl2
minor major
H2SO4

37. Polymerization Z = CH3 polypropylene polypropylene Z = Cl PVC PVC
Z = CN polyacrylonitrile
Z = OH polyvinyl alcohol
polypropylene
PVC
polyacrylonitrile
polyvinyl alcohol

39. Polymers & Health Bisphenol A = hard shell plastic
Pthalate, plasticizer