Organic Chemistry: Properties and Naming of Alkanes, Alkenes, and Alkynes, Study notes of Chemistry

Download Organic Chemistry: Properties and Naming of Alkanes, Alkenes, and Alkynes and more Study notes Chemistry in PDF only on Docsity! C h ap ter 22 - O rg an ic C h em istry 22.1 A lkanes: Saturated H ydrocarbons 22.2 A lkenes and A lkynes 22.3 A rom atic H ydrocarbons 22.4 H ydrocarbon D erivatives 22.5 P olym ers 22.6 N atural P olym ers T h e P o sitio n o f C arb o n in th e P erio d ic T ab le B o n d E n erg y an d th e S tab ility o f C arb o n C h ain s H yd ro carb o n s C + H C om pounds containing only carbon and hydrogen w ith only single bonds and no m ultiple bonds - Saturated hydrocarbons - A lkanes C n H 2n+2 C om pounds containing only carbon and hydrogen w ith only single bonds and no m ultiple bonds, but a ring structure - Saturated hydrocarbons - C ycloalkanes C n H 2n C om pounds containing only carbon and hydrogen w ith double bonds - U nsaturated hydrocarbons - A lkenes C n H 2n C om pounds containing only carbon and hydrogen w ith triple bonds - U nsaturated hydrocarbons - A lkynes C n H 2n–2 N am in g H yd ro carb o n s B ased on the longest chain of carbon atom s P refix + root + suffix L ocation and nature of substituents on chain (T able 22.2) Indicator of the # of C ’s in the longest chain (T able 22.1) C lass of organic com pound -ane for alkanes (-ene for alkenes -yne for alkynes) B o ilin g P o in ts o f H yd ro carb o n s T ab le 22.1 E xam p le P ro b lem : D raw in g A lkan es P roblem : D raw all possible structures for hydrocarbons that have: a) 7 C atom s, no m ultiple bonds, and no rings. b) 5 C atom s, one double bond, and no rings. c) 5 C atom s, no m ultiple bonds, and one ring. P lan: In each case, w e draw the longest carbon chain and then w ork dow n to sm aller chains w ith branches at different points along them . T he process typically involves trial and error. T hen w e add H atom s to give each C atom a total of four bonds. Solution: (only the carbon backbone w ill be show n here) a) com pounds w ith seven C atom s: (9) [C 7 H 16 ] C -C -C -C -C -C -C C -C -C -C -C -C C C -C -C -C -C -C C C C -C -C -C -C C C -C -C -C -C C C C -C -C -C -C C C C C -C -C -C -C C C -C -C -C -C C C C C -C -C -C C C D raw in g A lkan es (co n t) b) com pounds w ith 5 C atom s and 1 double bond: (5) [C 5 H 10 ] C =C -C -C -C C =C -C -C C =C -C -C C -C =C -C -C C -C =C -C c) com pounds w ith 5 C atom s and 1 ring: (5) [C 5 H 10 ] C -C -C -C C C -C -C -C C C C -C -C C C -C -C C -C C -C C C C C C C CH, cH-CH ~CH—CH;-CH;-CH, CH, CH, Condensed formula Depicting Cycloalkanes ACyclopropane BCyclobutane C Cyclopentane D Cyclohexane S o m e S tru ctu ral Iso m ers o f A lkan es A lken es C 2 H 4 E thylene H 2 C =C H 2 C 3 H 6 Propylene H 2 C =C H –C H 3 C 4 H 8 B utene H 2 C =C H –C H 2 –C H 3 C 5 H 10 Pentene H 2 C =C H –C H 2 –C H 2 –C H 3 C 6 H 12 H exene H 2 C =C H –C H 2 –C H 2 –C H 2 –C H 3 C 7 H 14 H eptene H 2 C =C H –( C H 2 )4 –C H 3 C 8 H 16 O ctene H 2 C =C H –( C H 2 )5 –C H 3 S o m e S tru ctu ral Iso m ers o f A lken es T h e In itial C h em ical E ven t in V isio n N am in g an d D raw in g A lkan es , A lken es, an d A lkyn es–II P lan: For (e), the longest chain that includes the m ultiple bond is num bered from the end closer to it. Solution: (a) C H 3 C H 3 C H 3 - C H - C H - C H 3 1 2 3 4 2,3-D im ethylbutane C H 2 - C H 3 H (b) C H 3 C H 3 - C H 2 - C H 2 - C - C - C H 2 C H 3 1 2 3 4 5 6 73-M ethyl-4-ethylheptane N am in g an d D raw in g A lkan es , A lken es, an d A lky n es–III (c) C H 3 H 2 H 2 H 2 H 2 C H 2 - C H 3 1 2 3 1-E thyl-3-m ethylcyclohexane (d) C H 3 C H 3 C H 3 - C H 2 - C - C - C H 3 H C H 3 1 2 3 4 5 2,2,3-T rim ethylpentane chiral center (e)C H 3 - C H 2 - C = C - C H - C H 3 H C H 3C H 3 C H 3 - C H 2 - C = C - C H - C H 3 H C H 3C H 3 cis-2,3-D im ethyl-3-hexene trans-2,3-D im ethyl-3-hexene C onsider carbon bonded to A , B , C , and D . T here are tw o possible structures. O rg an ic O p tical Iso m ers A D B C A D C B B and C do not superimpose T he tw o structures are m irror im ages of each other. T hey are optical isom ers of each other. E ach of the tw o form s is asym m etric - no plane of sym m etry. A n organic m olecule is alw ays chiral if it has a carbon atom that is bonded to four different groups. Representations of Benzene X ylen es –T h e T h ree Iso m ers o f C 8 H 1 0 C H 3 C H 3 C H 3 C H 3 C H 3 C H 3 1,2-D im ethylbenzene (o-xylene) bp = 144.4 °C 1,3-D im ethylbenzene (m -xylene) bp = 139.1 °C 1,4-D im ethylbenzene (p-xylene) bp = 138.3 °C N ap h th alen e an d B en zo [a]p yren e A rom atic C arcinogens N apthalene C 10 H 8 B enzo[a ]pyrene C 20 H 12