Concepts from Chemical Reaction Kinetics - Elements of Environmental Engineering: Thermodynamics and Kinetics - page 227

TABLE 5.4
Different Types of Acid-Base Hydrolysis Mechanisms in Environmental
Chemistry
Type Reaction Rate Expression Examples

H + SH + H + ][ I S + kK eq [ S ][ R ] Ester, amide, and ether

hydrolysis

SH + + W slow −−−→ P

SH + H + HSH + kK eq K a [ BH + ][ HA ]

II Hydrolysis of

alkyl-benzoimides,
keto-enol changes

slow
−−−→ BH + + SH HSH + + B

III HS + HA HS · HA kK eq [HS][HA][B] Mutarotation of glucose

HS · HA + B slow

−−−→ P

IV S + HA S · HA kK eq [S][HA][R] General acid catalysis,

hydration of aldehydes

S · HA + R → P
VS − + HA slow −−−→ SH + A − k [S − ][HA] Decomposition of

diazoacetate

SH fast

−−→ P

HS + B S − + BH + kK eq [SH][R][OH − ]/ K b

VI Caisen condensation

S − + R slow

−−−→ P

HS + B slow −−−→ S − + BH +

VII k [HS][B] General base catalysis

fast
−−→ products S −

i k Aromatic substitutions

ι ]+ j k j [ HA j ]

VIII R + S T [ T ]

ι [ B

IX HS + B B · HS kK eq [B][HS][R] General base catalysis,

ester hydrolysis

B · HS slow

−−−→ P
Source: From Moore, J.W. and Pearson, R.G. 1981. Kinetics and Mechanism , 3rd ed. New York:
Wiley-Interscience.
Note: S represents reactant, B is the general base, HA is the general acid, and R is a reactant whether
acid or base.

versus [acid] gives as intercept, k 0 = 1.35 × 10 − 4 min − 1 , and slope, k acid = 5.6 ×
10 − 5 L/mol min. The correlation coefficient is 0.992. This is a general method of
obtaining k . For catalysis by different species, each k value can be isolated as given
above.

E XAMPLE 5.13 E FFECTOF S USPENDED S EDIMENT (S OIL ) ONTHE H OMOGENEOUSLY
C ATALYZED H YDROLYSIS OF O RGANIC C OMPOUNDS

Since atmospheric moisture (e.g., fogwater and rain) and lake and river water contain
suspended solids, the rate of hydrolysis of organics is likely to be influenced by them.
This example will illustrate the effect for some organic compounds.
Many organic compounds that are common pollutants (e.g., pesticides—malathion
and dichloro-diphenyl-trichloroethane (DDT)) have low reactivity and are known
to associate with colloidal matter that has high organic carbon content (see Chapter 4).
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