ALKANA [ CnH2n+2 ] n RM alkana nama alkana rumus alkil Nama alkil 1 CH4 metana CH3 - metil 2 C2H6 Etana C2H5 - Etil 3 C3H8 Propana C3H7 - Propil 4 C4H10 Butana C4H9 - Butil 5 C5H12 Pentana C5H11 - Amil 6 C6H14 Heksana C6H13 - Heksil 7 C7H16 Heptana C7H15 - Heptil 8 C8H18 Oktana C8H17 - Oktil 9 C9H 20 Nonana C9H19 - Nonil 10 C10H22 Dekana C10H21 - Dekil

KEMUNGKINAN BENTUK ALKIL rantai utama CH3 CH2 CH2 CH―CH3 CH2 | | | | CH3 CH2 CH3 CH2 | | CH3 CH2 | CH3 metil etil propil isopropil butil

Kemungkinan cabang butil rantai utama CH2 CH- CH3 CH3- CH- CH3 CH2 | | | | CH2 CH2 CH3 CH- CH3 | | | CH2 CH3 CH3 | CH3 butil secunder butil tersier butil isobutil

Tata nama Alkana Carilah rantai C terpanjang dalam molekul sbg rantai induk 7 6 5 4 3 2 1 C C C C C C C C C C C 2. Berilah nomor urut pada rantai, dimulai dengan ujung yang membawa gugus sebagai nomor terkecil. 3. Setiap gugus diberi nomor kedudukan dan nama. Gugus yang ada pada contoh diatas adalah 2-metil, 3-metil, dan 4-etil 4. Dua nama gugus yang sama tidak perlu ditulis ulang, cukup diberi awalan yang menyatakan jumlah. Dalam hal ini, ada dua gugus metil sehingga cukup ditulis 2,3-dimetil 5. Nama gugus diurutkan berdasarkan abjad nama gugus dalam bahasa inggris (awalan yg menyatakan jumlah diabaikan) kemudian diikuti nama rantai induknya. Jadi nama senyawa diatas = 4-etil, 2,3-dimetilheptana

Reaksi alkana Alkana bersifat lembam: tidak bereaksi dgn kebanyakan asam, basa, zat pengoksidasi, atau pereduksi Berguna sebagai pelarut ekstraksi Reaksi yang ada: Pembakaran (oksidasi) CH4 + 2O2 CO2 + 2H2O + kalor 2. Halogenasi R-H + Cl-Cl R-Cl + H-Cl cahaya cahaya

Reactions of Alkanes Combustion An alkane + oxygen gives carbon dioxide plus water An important side reaction?

Reactions of Alkanes Halogenation—an alkane plus a halogen gives an alkyl halide (substituted alkane) plus a hydrogen halide (acid) CH4 + Br2 → CH3-Br + HBr CH3CH3 + Cl2 → CH3CH2-Cl + HCl

Alkane, reactions: Halogenation 2. Combustion (oxidation) 3. Pyrolysis (cracking)

Halogenation R-H + X2, heat or hv  R-X + HX a) heat or light required for reaction. b) X2: Cl2 > Br2  I2 c) yields mixtures  d) H: 3o > 2o > 1o > CH4 e) bromine is more selective

Combustion CnH2n+2 + (xs) O2, flame  n CO2 + (n+1) H2O + heat gasoline, diesel, heating oil… Pyrolyis (cracking) alkane, 400-600oC  smaller alkanes + alkenes + H2 Used to increase the yield of gasoline from petroleum. Higher boiling fractions are “cracked” into lower boiling fractions that are added to the raw gasoline. The alkenes can be separated and used in to make plastics.

propane n-propyl chloride Cl CH3CH3 + Cl2, hv  CH3CH2-Cl + HCl ethane ethyl chloride CH3CH2CH3 + Cl2, hv  CH3CH2CH2-Cl + CH3CHCH3 propane n-propyl chloride Cl isopropyl chloride 45% 55% gives a mixture of both the possible alkyl halides! 

n-butane n-butyl chloride CH3CH2CH2CH3 + Cl2, hv  CH3CH2CH2CH2-Cl 28% n-butane n-butyl chloride + CH3CH2CHCH3 72% Cl sec-butyl chloride CH3 CH3 CH3CHCH3 + Cl2, hv  CH3CHCH2-Cl 64% isobutane isobutyl chloride CH3 CH3CCH3 36% tert-butyl chloride

propane n-propyl bromide Br CH3CH3 + Br2, hv  CH3CH2-Br + HBr ethane ethyl bromide CH3CH2CH3 + Br2, hv  CH3CH2CH2-Br + CH3CHCH3 propane n-propyl bromide Br isopropyl bromide 3% 97%

n-butane n-butyl bromide CH3CH2CH2CH3 + Br2, hv  CH3CH2CH2CH2-Br 2% n-butane n-butyl bromide + CH3CH2CHCH3 98% Br sec-butyl bromide CH3 CH3 CH3CHCH3 + Br2, hv  CH3CHCH2-Br <1% isobutane isobutyl bromide CH3 CH3CCH3 99% tert-butyl bromide