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Chemistry 2100. Lecture 2. Alkynes and Alkenes. alkene (olefins) : C n H 2n. alkyne (acetylenes): C n H 2n-2. Ethyne. Ethene. Ethylene. Acetylene. Naming Alkenes and Alkynes. Parent name is that of the longest chain that contains the C=C or C ≡ C.
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Chemistry 2100 Lecture 2
Alkynes and Alkenes alkene (olefins):CnH2n alkyne (acetylenes): CnH2n-2 Ethyne Ethene Ethylene Acetylene
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.
2-methyl-2-pentene 3-methyl-cis-2-pentene 3-methyl-trans-2-pentene Alkene Isomerism
trans-retinal 11-cis-retinal
opsin rhodopsin
rhodopsin metarhodopsin
rhodopsin metarhodopsin
rhodopsin metarhodopsin
rhodopsin neural impulse metarhodopsin
neural impulse metarhodopsin 11-cis-retinal trans-retinal
neural impulse metarhodopsin 11-cis-retinal trans-retinal
neural impulse metarhodopsin 11-cis-retinal trans-retinal
neural impulse metarhodopsin 11-cis-retinal trans-retinal opsin
neural impulse metarhodopsin 11-cis-retinal trans-retinal opsin
-selinene (celery) caryophyllene (cloves) zingiberene (ginger) myrcene (bay) geraniol (rose) limonene (orange, dill) carvone (spearmint, dill) menthol (mint) Terpenes – natural polyenes
squalene ~25 steps cholesterol lanosterol
tetra tri di mono Making Alkenes
(cis or trans) Reactions of Alkenes Hydrogenation
• • "partially hydrogenated vegetable oil" Partially Hydrogenated Vegetable Oil
Halogenation CH2Cl2 RT ∆ / h Cl2 CH2Cl2
H2SO4 minor major H2SO4 Acid Addition CH2Cl2
polypropylene PVC polyacrylonitrile polyvinyl alcohol Z =CH3 polypropylene Z = Cl PVC Z = CN polyacrylonitrile Z=OH polyvinyl alcohol Polymerization
Polymers & Health Bisphenol A = hard shell plastic Pthalate, plasticizer