chemistry 2100
DESCRIPTION
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. - PowerPoint PPT PresentationTRANSCRIPT
Chemistry 2100
Lecture 2
Alkynes and Alkenesalkene (olefins): CnH2n
alkyne (acetylenes): CnH2n-2 CC
H
HH
H HCCH
Ethene EthyneEthylene 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 -eneene 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.
CH2CCH3 CH
CH2
CH3
Br CH3 C C C CH3
CH3
CH3
Constitutional
IsomersStereoisomers ConformationalIsomers
GeometricIsomersEnantiomers Diastereomers
single bond rotation
chiral achiral
sameconnections
differentconnections
notmirrorimages
mirrorimages
Isomers
Alkene Isomerism
C=CH3C
H H
HC=C
H3C
H CH3
Htrans-2-Butene
mp -106°C, bp 1°Ccis-2-Butene
mp -139°C, bp 4°C C C
H H
CH3 CH3
C C
CH3 H
H CH3
CH3CH2
CH3CH2
3-methyl-cis-2-pentene3-methyl-trans-2-pentene
2-methyl-2-pentene
C C
CH3 H
CH3 CH2CH3
Conjugation
-carotene
-carotene
[O]
-carotene
2
[O]
Vitamin A
CH2OH
Vitamin A
CH2OH
trans-retinal
[O]
CHO
Vitamin A
CH2OH
trans-retinal
[O]
CHO
Vitamin A
CH2OH
trans-retinal
[O]
CHO
Vitamin A
CH2OH
trans-retinal
11-cis-retinal
isomerization
CHO
[O]
CHO
Vitamin A
CH2OH
C O
H
H2N
opsin
C O
H
H2N
opsin
C O
H
H2N
opsin
C O
H (- H2O)
H2N
rhodopsin
opsin
C O
H C N
H
(- H2O)
metarhodopsin
rhodopsin
C N
H
C
H
N
h
metarhodopsin
rhodopsin
C N
H
C
H
N
h
metarhodopsin
rhodopsin
C N
H
C
H
N
h
neuralimpulse
metarhodopsin
rhodopsin
C N
H
trans-retinal
11-cis-retinal
neural
impulse
metarhodopsin
C
H
N H2O
C
H
O
+
trans-retinal
11-cis-retinal
neural
impulse
metarhodopsin
C
H
N C
H
O
+
H2O
trans-retinal
11-cis-retinal
neural
impulse
metarhodopsin
C
H
N C
H
O
+
H2O
H2N
opsintrans-retinal
11-cis-retinal
neural
impulse
metarhodopsin
C
H
N C
H
O
+
H2O
H2N
opsintrans-retinal
11-cis-retinal
neural
impulse
metarhodopsin
C
H
N C
H
O
+
H2O
Terpenes – natural polyenes isoprene
(2-methyl-1,3-butadiene)
CH3
CHCCH2 CH2
limonene(orange, dill)
myrcene(bay)
geraniol(rose)
menthol(mint)
carvone(spearmint, dill)
OH
OH
O
zingiberene
(ginger)
-selinene(celery)
caryophyllene(cloves)
CH2PPOCH2 OPP +
squalene
squalene
O2
cholesterol
~25 steps
HO
lanosterol
HO
Making Alkenes B""A
B
CC
A
+CC
tetra tri di mono
CC
R
RR
R>
'''
'''
CC
R
HR
R>
'''
CCH
HR
R>
'
CCH
HR
H
Reactions of Alkenes C C
BA
+ BACC
Hydrogenation
(cis or trans)
CH3
CH3 CH CH2CH3 CH3CH CHCH2CH3 Pt
H2 CH3CH2 CH2CH2CH3
CH3
CCH2 CH2CH3
CH3
CHCH3CCH3orPt
H2
Partially Hydrogenated Vegetable Oil
"partially hydrogenated vegetable oil"
+
COOH
COOH
COOH
H2 catalyst
• •
Halogenation C C
H
+ Br2 C C
Br
BrH+
CH2Cl2
RT
∆ / h
C C
BrBr
Br2CC +
CH2Cl2
Cl2
Cl
Cl
CH3CH3
Acid Addition
CH2Cl2
H ClCHCH3CH3CH + CHCH3
Cl
CH3CH
H
CH3CH
Cl
CHCH3
H
minor major
H BrCH2CH3CH2CH + +CH2CH3CH2CH
BrH
CH2CH3CH2CH
HBr
H2SO4
H2SO4
H OH CH3 CH2 OHCH2 CH2 +
CH2 + H OHCH3
OH
Polymerization
Z = CH3 polypropyleneZ = Cl PVCZ = CN polyacrylonitrileZ = OH polyvinyl alcohol
polypropylenePVCpolyacrylonitrilepolyvinyl alcohol
CH2 CH
Z
n CH2CHCH2CHCH2CH CH2CH
Z Z Z Z
Polymers & Health
Pthalate, plasticizerBisphenol A = hard shell plastic