Pertemuan Ke-8 Alkanes & Cycloalkane

8/18/2019 Pertemuan Ke-8 Alkanes & Cycloalkane

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Pharmacy Departement

Jenderal Soedirman University

Dr. Sri Sutji Susilowati, M.Si., Apt

M. Salman Fareza, M.Si.

!"A#$% %&'M$S(!) $!"A#$% %&'M$S(!) $

Al*anes + %ycloal*anesAl*anes + %ycloal*anes


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$. %lasses o- ranic %ompounds

&ydrocar/ons 0% + & only1 &eteroatomic compounds

aliphatic aromatic

al*anes

al*enes

al*ynes

cyclic compounds

alcohols

ethers

aldehydes

*etones

car/o2ylic acids

esters

amines

amides

% %

% %

% %

! &

! !3

! %

&

! %

!3

! %

&

! %

!3

! %

#&

! #&,


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4

$$. Al*anes

A. "eneral -ormula5 %n&n 6

%&7 methane 0natural as, swamp as1

%&4 8%&4 0%&91 ethane

%&4 8%& 8%&4 0%4&:1 propane 0;P"1

%&4%&%&%&4 0%7&?@:? %&7?@


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7

$$. Al*anes

B. $somers5 normal and /ranched al*anes

n@/utane

Cstraiht chain

/ranched chain

iso/utane

%&4 %&, %&, %&4

%&4

%& %&4

%&4

& % % % % &

& &

& &

& &

& &

constitutional

isomers

%7&


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?

$$. Al*anes


%?&


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9

$$. Al*anes


uestion @


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>

$$. Al*anes


Answer @


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:

$$. Al*anes


(ypes o- car/ons5

%&4 %&

%&4

%& %&4

methyl car/ons

methylene car/on

methine car/on


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E

$$. Al*anes

%. Structure@property relationships

$ntermolecular attractions5 ;ondon 0or van der Gaals1 -orces 0wea*1 /.p.

%&7 @


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$. %hemical Properties o- Al*anes

Answer @9. Determine whether the -ollowin reactions will

/e o2idation, reduction, or neither. %hec* your answers /y clic*in

on the arrow.

Check Answer

&% %& 6 Br &% %&

Br Br

&,% %&, 6 &, %

&

&

&

%

&

&

&

2idation5 'ach car/on

chanes -rom a @ to a @


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=

. %on-ormations o- Al*anes

B. Butane5 steric repulsions %&4 8%& 8%& 8%&4

%&4

%&4

%&4

&4%

%&4&4%

%&4%&4 %&4%&4

%&4

%&4

$

anti

0


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<

. %on-ormations o- Al*anes

B. Butane5 steric repulsions

$ $$ $$$ $ $

=

7

9

∆G

4.9=.:

K9

=.:4.9

%&4

%&4

%&4

&4%

%&4&4%

%&4

%&4

%&4%&4

%&4

%&4

$ $$ $$$ $ $


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$. %on-ormations o- %ycloal*anes

A. Sta/ilities o- cycloal*anes

!in strain L /ond anle strain

6 torsional strain 0eclipsin1

6 steric strain 0van der Gaals1


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A. Sta/ilities o- cycloal*anes∆ H com/

per %&

(otal

rin strain

.= 9.4

.4 E.9


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&&

&&

& & poor overlap L bond angle strain

0i.e.,


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&

&

&

&

&

&

&

&&

&

&

&

&&

&

&

planar, E=H /ut all eclipsed

Cpuc*ered, ::Hslihtly more anle strain,

/ut less eclipsin strain

%hem4D

planar,


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B. %on-ormations in cyclohe2ane

*cal

∆G K > *cal

%hem4D

Cskewed boat K


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. eRuatorial and a2ial positions

&

&&

&

&

&

&&

&

&&

&

&

&&

&

&

&

&&

&

&&

&

axial positions equatorial positions

4. chair@chair interconversion

&

&&

&

&

&

&&

&

&&

&

&

&&

&

&

&

&

&&

&&

&

E a K


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:



7. drawin cyclohe2ane chairs


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E


%. Su/stituted cyclohe2anes

%&4

%&4

&

&

&

%&4

&


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4=


%. Su/stituted cyclohe2anes

&

&

More pronounced e--ect with larer roups5

∆G K ?.? *cal

0EE.EE1 0=.=


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4<


D. Disu/stituted cyclohe2anes

%&4

%&4

%&4

%&4

trans@ cis@


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%&4

%&4

%&4%&4

&

&

%&4 &

%&4

&

%&4

%&4

∆G K 4.9 *cal

dieRuatorial

no repulsions

dia2ial

7


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%&4

%&4

&4% %&4

%&4

%&4

&

&

&

%&4

%&4

&

∆G L = *cal

eRuatorial@a2ial

2 =.E L


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%&4

%&4

%&4%&4

&

&

& %&4

%&4

&


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4?



%&4

%&4

%&4&4%

& %&4%&4

∆G K ?.7 *cal

no repulsions


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;arer roups predominate in determinin con-ormation5

%&4

%&4

t Bu

%&4

∆G K 4.> *cal


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4>



uestion 4@


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4:



Answer 4@

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Pertemuan Ke-8 Alkanes & Cycloalkane