aliphatic nitro cpd.

R-NO₂

ca. 10¹²

ca. -12

aryl nitro cpd.

C₆H₅NO₂

ca. 10¹¹

ca. -11

nitriles

R-C≡N

ca. 10¹⁰

ca. -10

aliphatic aldehydes

R-CH=O

ca. 10⁸

ca. -8

aryl aldehydes

C₆H₅CH=O

ca. 10⁷

ca. -7

aliphatic ketones

R₂C=O

ca. 10⁷

ca. -7

esters

R-CO₂R'

ca. 3 * 10⁶

ca. -6.5

aryl alkyl ethers

C₆H₅OCH₃

ca. 3 * 10⁶

ca. -6.5

phenols

C₆H₅OH

ca. 3 * 10⁶

ca. -6.5

aryl ketones

C₆H₅COCH₃

ca. 10⁶

ca. -6

carboxylic acids

R-CO₂H

ca. 10⁶

ca. -6

sulfides

RSR

ca. 10⁵

ca. -5

diethyl ether

C₂H₅OC₂H₅

ca. 3 * 10³

ca. -3.5

dioxane

O(CH₂CH₂)₂O

ca. 10³

ca. -3

pyran

(CH₂)₅O

ca. 3 * 10²

ca. -2.5

tetrahydrofuran

(CH₂)₄O

ca. 10²

ca. -2

alcohols

R-CH₂-OH

ca. 10²

ca. -2

aryl amides

C₆H₅C(NH₂)=O

ca. 10²

ca. -2

indole

ca. 10²

ca. -2

water

H₂O

55

-1.74

aliphatic amides

RC(NH₂)=O

3.2

-0.5

dimethyl sulfoxide

(CH₃)₂SO

1

0

phosphine oxides

R₃PO

1

0

pyrrole

C₄H₄NH

1

0

urea

(NH₂)₂C=O

0.8

0.1

diphenylamine

(C₆H₅)₂NH

0.15

0.8

p-nitroaniline

4-O₂NC₆H₄NH₂

0.1

1.0

aniline

C₆H₅NH₂

2.5 * 10^-5

4.6

trimethylamine N-oxide

(CH₃)₃NO

2.5 * 10^-5

4.6

N,N-dimethylaniline

C₆H₅N(CH₃)₂

10^-5

5.1

pyridine

C₅H₅N

6.3 * 10^-6

5.2

hydroxyl amine

HONH₂

1.3 * 10^-6

5.9

2,6-dimethylpyridine

2.0 * 10^-7

6.7

imidazole

10^-7

7.0

hydrazine

H₂NNH₂

10^-8

8.0

alkyl phosphines

R₃P

10^-8

8.0

aziridine

10^-8

8.0

2,2,2-trifluoroethylamine

CF₃CH₂NH₂

5.0*10^-9

8.3

morpholine

O(CH₂CH₂)₂NH

5.0*10^-9

8.3

DABCO

K₁ = 2.0 * 10^-9
K₂ = 6.3 * 10^-5

 8.7
 4.2

ammonia

NH₃

5.62 * 10^-10

9.25

4-dimethylaminopyridine

4-(CH₃)₂N-C₅H₄N

2.0 * 10^-10

9.7

ethyl amine

C₂H₅NH₂

2.0 * 10^-11

10.7

triethyl amine

(C₂H₅)₃N

1.8 * 10^-11

10.8

diethyl amine

(C₂H₅)₂NH

10^-11

11.0

piperidine

(CH₂)₅NH

10^-11

11.0

pyrrolidine

(CH₂)₄NH

6.3 * 10^-12

11.2

Hünig's base

3.4 * 10^-12

11.4

DBU

10^-12

12

proton sponge

4.4 * 10^-13

12.3

guanidine

(NH₂)₂C=NH

2.0 * 10^-14

13.6

pentamethylguanidine

[(CH₃)₂N]₂C=NCH₃

1.8 * 10^-14

13.8