Download Organic Chem Test Aids

Strengths of Acids and Bases
acid
weakest
acids
Cannot
protonate
water
pKa
conjugate base
pKb
CH4
~ 55
~ -41
C2H4
44
:CH3:C2H3C6H5-
-29
-21
C6H6
NH3
43
35
H2
35
C2H2
25
Protonate
water
increasingly.
:NH2-
-30
:H:C2H-
-21
-11
(CH3)2CO
(CH3)3COH
20
18
CH3COCH2(CH3)3CO-
-6
-4
CH3CHO
C2H5OH
17
16
CH2- CHO
C2H5O-
-3
-2
H2O
15.74
OH-
-1.74
12.3
PO4-3
1.7
10.6
CH3NH2
3.4
C6H5OH
10.0
4.0
HCN
NH4+
9.3
9.2
C6H5OCN-
CH3SH
H2PO4H2S
HPO4-2
CH3NH3+
Determined
in water.
(pKa + pKb) = 14 for conjugate acid-base pairs
NH3
4.7
4.8
8
7.2
CH3SHPO4-2
6
6.8
7.1
HS-
6.9
6.4
HCO3-
7.6
C6H5SH
C5H5NH+
6
5.3
C6H5SC5H5N
8
8.7
HN3
CH3COOH
4.7
4.7
N3CH3COO-
9.3
9.3
C6H5NH3+
4.6
C6H5NH2
9.4
H2CO3
COO-
C6H5COOH
4.0
HF
H3PO4
CF3COOH
3.2
2.1
0.2
CF3COO-
10.8
11.9
13.8
C2H5COH+NH2
HNO3
-1
-1.4
C2H5CONH2
NO3-
15
15.4
H3O+
-1.74
HOH
15.74
CH3CH2OH2+
-3.6
CH3CH2OH
17.6
Protonate
water
completely
H2SO4
-5
HSO4-
19
HCl
HBr
HI
strongest
acids
C2H5CNH+
HClO4
HSbF6
-7
-8
-9
-10
-10
< -12
ClBrIC2H5CN
ClO4SbF6-
21
22
23
24
24
>26
Test Aids
C6H5
FH2PO4-
strongest
bases
Completely
protonated
by water
Determined
in water.
Protonated
by water
increasingly.
10.0
Not
protonated
by water
weakest
bases
1
Approx. pKa values of functional groups
Approx. pKb values of functional groups
pKa
55
45
group
alkane
alkene
example
CH4
CH2=CH2
pKb
24
23
group
nitrile
acid chloride
35
25
20
17
17
15 - 18
15.74
10
9.3
8
7
6
5
-1.74
-2
-7
ammonia
alkyne
ketone
amide
aldehyde
alcohol
water
phenol
hydrocyanic acid
aliphatic thiol
hydrogen sulfide
aromatic thiol
carboxylic acid
hydronium ion
protonated alcohol
mineral acid
NH3
CH CH
acetone
methanamide
ethanal
ethanol
H2O
-OH
HCN
CH3SH
H2S
-SH
CH3COOH
H3O+
CH3CH2OH2+
HCl
22
21.2
20.5
20
17.6
16 - 18
15.74
15
9.3
9
7.6
6.0
4.7
4.6
4
3
-1.74
-2
aldehyde
ketone
ester
carboxylic acid
ether
alcohols
water
aliphatic amides
acetate
aromatic amine
bicarbonate
aliphatic sulfide
cyanide
ammonia
phenoxide
aliphatic amine
hydroxide
alkoxide
borohydride
aluminum hydride
Grignard
hydride
sodium amide
1 carbanion
sodium
-21
-21
-41
Test Aids
example
CH3CN:
ethanoyl
chloride
ethanal
acetone
ethyl acetate
acetic acid
C2H5OC2H5
CH3CH2OH
H2O
ethanamide
CH3COO-NH2
NaHCO3
CH3SCNNH3
-OCH3NH2
OHCH3CH2ONaBH4
LiAlH4
CH3- +MgBr
Li+ :HNa+ :NH2Li+ :CH3Na0
2
pKeq vs. Extent of Reaction (% )
[pKeq = pKa + pKb - 14]
pKeq
20
10
0
-10 0
10
20
30
40
50
60
70
80
90 100
-20
Extent of Reaction (%)
Test Aids
3
Functional Group Precedence in Nomenclature
Functional Group
Name as Suffix
Name as Prefix
Carboxylic Acids
-oic acid
–carboxylic acid
carboxy
Acid Anhydrides
-oic anhydride
-carboxylic anhydride
Esters
-oate
Principal Groups
alkoxycarbonyl
-carboxylate
Acid Halides
-oyl halide
-carbonyl halide
halocarbonyl
Amides
-amide
-carboxamide
amido
Nitriles
-nitrile
-carbonitrile
cyano
Aldehydes
-al
-carbaldehyde
oxo
Ketones
-one
oxo
Alcohols
-ol
hydroxy
Phenols
-ol
hydroxy
Thiols
-thiol
mercapto
Amines
-amine
amino
Imines
-imine
imino
Alkenes
-ene
alkenyl
Alkynes
-yne
alkynyl
Alkanes
-ane
alkyl
Subordinate Groups
Azides
azido
Diazo
diazo
Ethers
alkoxy
Halides
halo
Nitro
nitro
Sulfides
alkylthio
Principal functional groups are listed in order of decreasing priority; subordinate functional groups have no established
order of priority.
Test Aids
4
ELECTRONEGATIVITY:
Linus Pauling's Table of Electronegativities
H
2.1
Li
1.0
Na
1.0
K
0.9
Rb
0.9
Cs
0.8
Fr
0.8
Be
1.5
Mg
1.2
Ca1
.0
Sr
1.0
Ba
1.0
Ra
1.0
Sc
1.3
Y
1.2
La
1.1
Ac
1.1
Ti
1.4
Zr
1.3
Hf
1.3
V
1.5
Nb
1.5
Ta
1.4
Cr
1.6
Mo
1.6
W
1.5
Mn
1.6
Tc
1.7
Re
1.7
Fe
1.7
Ru
1.8
Os
1.9
Co
1.7
Rh
1.8
Ir
1.9
Ni
1.8
Pd
1.8
Pt
1.8
Cu
1.8
Ag
1.6
Au
1.9
Zn
1.6
Cd
1.6
Hg
1.7
B
2.0
Al
1.5
Ga
1.7
In
1.6
Tl
1.6
C
2.5
Si
1.8
Ge
1.9
Sn
1.8
Pb
1.7
N
3.0
P
2.1
As
2.1
Sb
1.9
Bi
1.8
O
3.5
S
2.5
Se
2.4
Te
2.1
Po
1.9
F
4.0
Cl
3.0
Br
2.8
I
2.5
At
2.1
Oxidizing Reagents for Organic Chemistry
Oxidant (media)
Reduced Form
Oxidant
Reduced Form
(purple) MnO (OH or neutral)
MnO2 (brown ppte.)
X2, e.g., Cl2
X-, e.g., Cl-
(purple) MnO4- (H+)
Mn+2 (colorless, aq.)
H2O2
2 O-2
hot conc. HNO3
NO2 (brown gas)
O2
2 O-2
(orange Cr+6 ) H2CrO4 (aq. H2SO4)
Cr+3 (blue-green)
Pb(OAc)4
Pb(OAc)2
4
-
+6
PCC (still Cr ) (in CH2Cl2)
Cr (blue-green)
Hg(OAc)2
HgOAc
HIO4 (colorless)
HIO3 (colorless)
NaOCl (bleach)
Cl-
+3
H2CrO4 is prepared by dissolving CrO3 (chromia or chromic anhydride) or K2Cr2O7 in aq. H2SO4.
Jones reagent:
CrO3 + H2SO4 (aq.) + acetone  H2CrO4
Pyridinium Chlorochromate (PCC): CrO3 + C5H5N: + HCl  C5H6NCrO3Cl
Collins Reagent: CrO3 + 2 C5H5N:  (C5H5N)2CrO3
Cr+6 in aqueous acid soln. are strong oxidants. Cr+6 in anhydrous solvent are mild oxidants.
Reducing Agents for Organic Chemistry
Reducing Reagent (conditions)
Oxidized form
H2 (g) (Pt, Pd, Ni, etc. catalyst in EtOH)
H+
LiAlH4 (in ether) liberates :H-
H2
NaBH4 (in EtOH) liberates :H-
H2
BH3 (g)
H2
Li, Na, K, Zn, Hg, Mg, etc.
Li , Na , K+, Zn+2, etc.
SnCl2 + 2HCl = H2SnCl4
H2SnCl6
Zn[Hg] + HCl
ZnCl2 + H2
Test Aids
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+
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