Geochemical Processes at Mineral Surfaces - ACS Publications

22 Abiotic Organic Reactions at Mineral Surfaces Evangelos A. Voudrias and Martin Reinhard Environmental Engineering and Science Group, Department of Civil Engineering, Stanford University, Stanford, CA 94305-4020 Abiotic organic reactions, such as hydrolysis, elimina tion, substitution, redox, and polymerization reactions, can be influenced by surfaces of clay and primary miner als, and of metal oxides. This influence is due to adsorption of the reactants to surface Lewis and Bronsted sites. Temperature and moisture content are the most important environmental variables. Under ambient envi ronmental temperatures, some reactions are extremely slow. However, even extremely slow transformation reac tions may be important from environmental and geochemical viewpoints. Abiotic

organic

include

hydrolysis,

reactions

ization.

The e f f e c t

(increase

the rate

tions

that

surfaces tion

that

may b e i n f l u e n c e d

elimination, of

of)

may o c c u r

may p r o m o t e

substitution,

the surface

may b e e i t h e r

or to i n h i b i t

(decrease solution.

reactions

do n o t o c c u r

that

concentrating

molecules

(_1) > b y s t a b i l i z i n g

intermediates

(2),

would

not otherwise

Generally, the

surface

be r e a c t i v e

the reactions

site

S t o form

of

A + If

S is

consumed,

depleted.

However,

catalyst),

the reaction

latter

case,

following (2) the face

S is will

the surface

elementary

A forms

successor

when

complex

(B*S)

transition state

after

denoted

reac mineral

i n homogenous

the mineral

a n d by a c t i v a t i n g involve

(Equation

solu

surface

components

a substrate

A at

1): (1)

regenerated

precursor

at

proceed

proceed

reaction

of)

In a d d i t i o n ,

-> Β

will

processes:

the surface

Β

S

the reaction

promote

(3).

interest

product

to

surfaces

and polymer

the rate

i n homogeneous

by s e l e c t i v e l y

that

by m i n e r a l

redox,

until

(i.e.,

until

reactant

complex

overcoming

S is

A is

may b e v i e w e d (1)

either

acting

consumed.

which

(A*S)#, a n d ( 3 )

as a

Β desorbs

of the

to s i t e

then

the a c t i v a t i o n

is

In the

as a sequence

A adsorbs

(A*S)

S or A

energy from

S,

forms

the

of

the s u r -

(4): A +

S

A. ..S

—

>

A...S

(2) (3)

^ ζ έ A*S

A*S

-çz±

(A*S)#

B*S

^ ±

Β +S

çz±

B*S

0097-6156/ 86/ 0323-0462$07.25 / 0 © 1986 A m e r i c a n C h e m i c a l Society

(4) (5)

22.

VOUDRIAS A N D REINHARD

This a

scheme

disregards

simplified

tions, or

such

model.

bonds.

formation

not

i f

sorbing,

upon

cases

a c t i v a t i o n energy

ate

formation, will

stabilized energy sites

barrier;

effect

a special

ately

sorbing

surface

case

quantification sediment

strates

(4)

present sediment

defined

systems

systems,

spectroscopic Soma

The need

ants use

of clays

The

and (6)

been

(review

purified

the fate

environments

as c a t a l y s t s

Bronsted

or basic

interactions increases, surface

i n terms 6_, 8,

increasingly

complexes

i n the b r o a d

a

single to

recover

o r c o m p o n e n t s may may b e mass

trans

reactions

to relatively

well-

mass

and recent

to

works by

limitations are

(19).

organic

reactions in soils

petrogenesis

and e v o l u t i o n

stems

from

and p o l l u t

(20-27),

of l i f e

processes

and as pigments

may b e c o n s i d e r e d

acidity

functional

(1_, 5,

from

humifi-

(1_, 3 0 ) , t h e

(31-37),

and f i l l e r s

in

i n

phar

paper,

(37).

surface

be u n d e r s t o o d

sub

are accessible

(8)

of pesticides (8),

sur

because

many

of organic

which

where

minerals

in industrial

(3),

(2)

phases

by Theng

oxides,

or primary

by m i n e r a l

characterization

are difficult

restricted

clays,

products.

may b e c o m p e t i n g f o r

the reactions

mostly

moder

of d e t a i l d e

i s complicated

active

i n mineral-promoted

and rubber

(1)

investigations

as homoionic

applications

and/or

acidic

used

have

(13-18),

mineral

desorbing

catalyzed

that

repre

apply:

activated

at the level

may b e f o r m e d

unknown

(19, 28, 29), the o r i g i n

plastic,

may

(5)

mechanistic

to understand

maceutical

Lewis

products

investigation

i n sedimentary

cation

stabilized

of properties

may b e f o r m e d

interme

catalysis

with

a range

appreciable

conditions

to easily

are

high

but not too stable

to characterize;

such

interest

Thus,

sites

by a

the reaction

reasons:

surface

solution

complexes

"a catalytic

is difficult several

et a l . (9-12)),

insignificant

react

for several

matrix;

Thus,

(7_) ·

information

i n the sediment;

limited.

the

(3)

of

restrictive

i n turn

of active

products

the mineral

easily"

that

not lower

the reaction

at

readily,

2 to 5 f o r reactions

surface

sites;

substrate;

in

which

and products

reaction

energy

i t i s formed

does

be s l o w e d

proceed

A is

of the intermedi

surface

will

i f

and t r a n s

to the bulk

states

form m o d e r a t e l y

difficult

the

fer

that

step

several

(1)

be formed

too strongly,

cannot

the p o t e n t i a l

f o r which

by Equations

is quite

formation

of catalysis

mechanistic

and

be

i f

enough

complexes,

scribed

from

rule

2 t o 5,

complexation

relative

i f Β i s sorbed

substrates

Obtaining faces

product

i t c a n be decomposed

sents

will

polar

complex

6).

F o r example,

or successor

and the r e a c t i o n

i s observed

that

acceleration

and (4)

i s stable

surface

formation,

hydrophobic

for small

of reactions

complex

i f precursor

too strongly,

Sabbatier's

diate so

(3)

are blocked

rates.

surface

(J>,

only

interac

to the surface

i s large

rates

i f

or

are insignificant

moiety

(2)

specific

o r π-complex

of the r a t e - c o n t r o l l i n g

no r a t e

occur;

and represents

as v a n d e r Waals

c a n be e v a l u a t e d .

not occur;

the case

limitations

significantly

the relative

no p r e c u r s o r

will

463

Reactions

coordination, such

interactions

the hydrophobic

limiting

formation

bonds,

b u t may c o n t r i b u t e

Depending different

transfer

interactions,

Non-specific

molecules,

mass

Organic

F o r m a t i o n o f A * S may i n v o l v e

as hydrogen

non-specific

Abiotic

source S as

groups.

Reactions

involving

acid/base

o r Bronsted

38).

As the a c i d i t y

weak b a s e s of

sites

of Lewis

the word,

of

localized

such

sites

acid/base

of the reactive

are neutralized

( A * S ) may b e f o r m e d . sense

as a s o l i d

and the r e a c t i v e

The term

"acidity"

including both

sites

and r e a c t i v e is

Bronsted

often and

464

G E O C H E M I C A L P R O C E S S E S AT M I N E R A L S U R F A C E S

Lewis

acidity.

mineral to

accept

will

discuss

surfaces

Reactions

in

Minerals

the

higher

both

41).

in

act

can

the

Lewis

an

oxidizing processes

species.

be

ability

acidity

The

related

to

of

to

the

the

agent

ability

(39).

involving review

We

mineral

has

been

sedimentary

conditions

significance.

the

Lewis

Lewis

and

Br^nsted

upper

Lewis

compounds and

reactions

Table

II.

9j

is

Acidity

of

obtained

by

with

lar

the

state

high.

may b e

aromatic the

(44,

type

and

depending

the

reactions sites

the are

may

promoted

reversibly with

such

degree

or as

of

Examples

summarized

Solomon

in

and

ESR and

IR

between

of

distinct

two

remains

45,

ring

47).

type

II

Recent

work may

(9)

studied

conditions

IR,

absorption

adsorbed

on C u

cation. in

the

at +

and

Ru

3 +

interlamel-

Cu

-montmoril-

π-complex

a

planar), the

parent

and

they

Oxidation

by

the

dimers,

presence

of

water

On t h e

or

in dis

that

both

polymers,

a

Ru^ (DMBO)

basis

that

of

and under Raman,

DMOB

is

montmorillonites

as

c a t i o n was

vapor:

is

which

compound.

demonstrated

metal

II

demonstrated

p-dimethoxybenzene

-exchanged

in

type

aromaticity

has

the metal

that

type

I,

more

and

and

monomers,

the

and,

substituents

transition

indicated

room t e m p e r a t u r e .

spectra, 2

the

i n t e r a c t i o n between

m o n t m o r i l l o n i t e and

desiccating VIS

of the

becomes

donating

molecules

and

infrared

42-48)

decreases,

of

(10-12) be

spectro

(9-12).

content

(i.e.,

distorted

substitution

-exchanged

types:

has

transfer

(ESR),

30,

transfer

have

of

resonance (9,

Insight

acidity

charge

combination

electron

aromatic

complexes

a

aromatic

spin

potential

intact

is

of

charge has

spectra

formed ring

for

Reactions.

i n v o l v i n g Lewis

(UV/VIS)

moisture

the

reversible

(12,

state

compete

on

by

spectroscopy

reduction

al.

radical

metal

conditions.

Oxidation

using

ring

on

and

Reduction

process

acid

acidity

formation

Raman

Soma e t

stably

octahedrally

properties,

reviewed

electron

potential

the

aromatic

turbed I

base

depends

absorption

aromatic

alkyl),

and

complexes

which

and

valence

the

strongly

Lewis

been

,

lower

desiccating

by

mineral cations

(38).

reversible

Lewis

Lewis

smectites

including

the the

O H , OMe,

lonite the

when

is

I.

acidity

clay

transition

affect

thus

F o r m a t i o n and

resonance

Generally,

cation

Table

under

studying

various

recently,

(e.g.,

that

may

weaker

ultraviolet/visible

valence

the

r e a c t i o n mechanisms

techniques,

favorable

in

have

Cu

edges

(octahedral)

cations

promoted

Complex

been

most

and

3

a

in

in a

(37).

Transfer

complexes

Fe *

crystal is

Lewis

are

heterogeneous

(IR),

have

sites

t r a n s i t i o n metal

state

which

examples

into

scopic

listed

strongest

that

as

Factors

42),

that

Other

Howthorne Charge

are

acid

(40)

the

oxidation

hydrocarbons.

hydration

such at

structural

bases.

(6_,

Lewis

structural

state,

and

acidity

aromatic

Acids.

or


water

ganic

(2)

valence

the

as

Lewis

adsorb

Cu

as

inorganic

which

aluminum exposed

Thus,

also

of

act

to

and

heterogeneous

or

by

exchanged

cations

by

as

exchangeable

coordinated of

to

mechanistic

Promoted

refers

proton

Minerals

Clay are

of

systems

have

a

i.e.,

organic

to

acidity

donate

examples

and

which

Clay

to

electrons,

restricted or

Br^nsted

surface

found

to

be

a

22.


Table

I.

Parameters of

Type

of

Clay

Lewis

1. L e w i s edge

of

-

t r a n s i t i o n metal interlayer 2. Lewis

base

-

t r a n s i t i o n metal the i n t e r l a y e r

-

clay

-

interlayer

-

redox

-

polarization

by Lewis

unsatisfied

incorporated

into

state

the clay

i n the interlayer

cations region

or

i n the lower

spacing,

incorporated

into

state

the clay

swelling

power

Properties

size

-

ionization stability

potential

-

Lewis

-

complexation

-

redox

of

radical,

radical

basicity/acidity ability

potential

of

Conditions

moisture

content

temperature

-

oxygen

-

organic

-

humic

co-solutes substances

i n

region oxidation

potential

-

exchanged structure

sites:

density

Reaction

Sites

coordination

oxidation

structure

Substrate

-

Promoted

Properties

charge

-

with

i n the upper

or

cavities

-

-

ions

ions

region

ditrigonal

Clay

Reactions

sites:

metal

in

465

Reactions

Site

-

the

Controlling

Organic

Minerals

acid

sites

Abiotic

substrate

cation

intermediates

exchanged structure.

466

G E O C H E M I C A L PROCESSES AT M I N E R A L SURFACES

Table

II.

Organic Clay

Reactions

Affected

Reaction Charge

Surface

Lewis-Acidity

Examples

Transfer

Complexation

N-heterocycles Formation

by

of

Minerals

of

of

(30)

riboflavine

Monomeric

p-substituted

References

ben-

Cations

from

p-dimethoxybenzene

(55)

4,4*-dimethoxybipheny1

(12)

zenes 4,4 -substituted f

biphenyls Dimerization

of

monosubstituted zenes,

ben-

toluene,

mesitylene,

phenol

symm.

with

biphenyl,

arenes

anisole

ethers

with

with

Oligo-

and Polymerization

aromatic

Cu(II)-M

(46)

Cu(II)-H,

butylphenyl 4.

(44)

naphthalenene,

anthracene aromatic

xylenes

Cu(II)-S

(45)

ether

of

hydro-

carbons

benzene, phenol,

phenols

(42)

toluene phenol

phenol-amino

mixtures, acid

mixtures

(49, 61,

symm.

benzene,

arenes

biphenyl, (46)

anthracene aromatic with

anisole,

ethers

butylphenyl

ether

aniline Ligand

Exchange

aromatic

(2,

by M

by F e ( I I I ) ,

Cu(II)-M

Hydrogen alkyl

Exchange

hydrogens

H^O a g a i n s t

H-cumene

aniline

in

Oxidation

(64)

detritiation

to

p-menthene (56,

p-cumene

by

phenols

phenol

S to

(54)

benzoquinone with by

Fe(III),

Cu(II)-S

methyl M: m o n t m o r i l l o n i t e ;

and C l - p h e n o l H:

hectorite.

(49) (45)

Cu(II)-S

2,6-dimethylphenol smectite;

90)

of

hydroquinone

anisole

S:

(24)

of

limonene and

8.

51)

64)

of

Disproportionation

alkenes

40,

(28,

Reactions

amines

Cu(II)-H

Redox

55)

(43)

4,4*-diaminobiphenyl

amines

(benzidine)

7.

(45,

Cu(II)-H

aromatic

5.

55,

2 9 , .L4 )

by S

(55) (57)

22.


Cu

2 +

(H 0) [clay] 2

In

+ DMOB

n

subsequent

work,

4,4 -dimethoxybiphenyl

ESR,

readily cate

reduced

layer) In

able

+

cations

protects

was

suspected

Another tion 43,

of

by t h e c l a y

produced.

respect gested

8).

and

a

In fast

the case

slow

sphere, reaction under

with

treatment crystal the

opposed

coloring

with

0

2

also

surface-adsorbed

a n d was t h e

not react

fast

to a

with

of

McBride

Fe(III)

2

,

of (2)

Fe(III) for

at

coloring also

to exchangeable were

found

cations

reaction

(2).

The

in a N

small

atmo-

2

quantities

of

coloring

i t

did not occur

was e x p l a i n e d

by

by t r e a t m e n t

to Fe(II),

of

and by

of the

the action

of

i n h i b i t i o n of the

the s o l u t i o n

the edges.

but, interestingly,

whether

at the

deactivation that

sug-

(divalent

about

interpreted pH o f

with 40, 52);

has been

iron

was p r e v e n t e d

He s u g g e s t e d

impurities

(2,

observed

because

is

yellow

exchangeable

reaction

polyphosphate

transfer

or

occurred

by 0

this

reduction

the A l ions

possible

are f e r r i c

40,

radical

a

cation

extremely

due t o t h e i n c r e a s e d of

product

The i n t e n s e - b l u e

(2).

oxida(2,

molecule

system,

disagreement

which

the

monovalent

faint-blue

of

is

clays

product

r e a c t i o n were

formation

However,

by e l e c t r o n is

rate

differently. is

other, Toluene

i n the l i t e r a t u r e

the edges,

to o x i d a t i o n Color

the clay

also

reaction,

for

a blue

the r a d i c a l

to o x i d a t i o n

2

to b l o c k i n g

benzidine Fe

a

hectorite,

0 ·

of

the c l a y

of

(43).

in

molecules

4 9 ) , but

benzidine

the yellow

is

of

at

hydrazine

polyphosphate

reaction

and

of

edges

of

various

the yellow

of

aluminum ions

coloring

of

of

form

There

T h e much s l o w e r

diffusion

does

clay-benzidine

hectorite,

was a t t r i b u t e d

2

density

reaction

of

disagreement

by s t r u c t u r a l F e ( I I I )

Ν ·

clay

is

sites


benzidine

the

of

transfer

formation

identity

intense-blue

faint-blue

of

in parallel.

that

the colorless

the blue

52).

(2,

surfaces,

d>

slow

of

electron-accepting

planar

from

the protonated

cation)

However,

anisole

(12,

ap-

exchange-

fraction

the high

to occur

investigated

electron

There

i n the case

t o be

radical the

drying

appear

the

ions.

neutral

i n the presence

with

to the chemical

however,

of

with

the l a t t e r

of

a significant

anisole

(12).

An e l e c t r o n

Upon

is

one-eighth

because

its

s i l i -

further

Formation of

access

with

and

water.

reacts

a r e Na

radi-

and i s

strongly cation,

to a methylphenylphenylmethane

benzidine

cation.

perhaps

benzene

well-studied

color

by w a t e r

with

which

only

f

montmorillonite,

to 4,4'-dihydroxybiphenyl

product

aqueous

abstracted

where

restricts

to react

50, 51).

reaction

Raman,

4,4 -DMOBP

to 4,4'-DM0BP

interacts

form,

-exchanged

that

exchange

the 4,4'-DM0BP.

reactions

monosubstituted

biphenyl-type

found

of

c h l o r o - and

and resonance

to attack

and the remaining

reacts

yet identified,

a n d Ru

The o t h e r

cation

are stable,

the reactions

molecule,

i t against

(6)

2

toluene,

corresponding

+

complexes

-,

They

Cu - m o n t m o r i l l o n i t e ,

cations Phenol

Fe

the metal-exchanged

i n a clay

not only

of

a r e Cu

-anisole

both

+ DMOBÎ + m H 0

studied

conditions

susceptible

,

to form

exchanged

(12).

is

to i t s r a d i c a l

anisole

anisole Cu

which

(12)

-,

2

[clay]

n - m

anisole,

spectroscopy.

4,4 -DMOBP

quantitative

fully

Cu

to 4,4*-DMBP.

the presence

neutral

with

complexes,

(e.g.,

converted

pears

of

a l .

dessicating

One c o m p l e x

surroundings

is

under

two t y p e s

cation.

Soma e t

2

f

and VIS a b s o r p t i o n

forms cal

+

467

Reactions

Cu (H 0)

and phenol

montmorillonite

Organic

(4,4 -DM0BP),

,

fluorobenzene,

Abiotic

Oxidation

cations different inactive

as of

s u c h as Cu forms (2).

of

468


The also

role

of

levels

(i.e.,

dehydration

Fe

to Fe

+

The

of

The with

other

alkali of

Laponite

(53)

Similar

or absence

organic

took

behavior

Oxygen radical

Cu

as ·

molecules, organic

reactants.

the e l e c t r o n

formation (56). may

of

oxidation

or polymers

This

occurs

is

In the presence

of

0

2

,

Fe

hydroquinone of

cation

+

.

to

biphenylof

(55).

to the

to o x i d i z e may r e a c t

was

o r Cu

atmosphere

the C u

transfer

between

the

with

between

redox

phenol phenol

adsorbed

disproportionation

two i d e n t i c a l

from

polymers

increased

acid-catalyzed.

were

of

Oxygen

i n the i n t e r l a y e r

termed

and p-menthene

disproportionation

i n the

(55).

electron

process

8)

in a

aniline

The f o r m a t i o n

which

sec-

saturated

oxygen.

of

proposed

radical,

factor

were

of

of

i n a nitrogen

been

(see

(Equation

i n the presence

cations

to reoxidize

has also

of

left.

a critical

(54).

(40).

water

the clays

2,6-xylenol

retarded

transfer

be B r ^ n s t e d

is

to the

i n the oxidation

from

promote

p-cymene

7)

was

adsorption

equilibria

benzidine

i n the presence

t o t h e phenoxy

may a l s o

of

When

slurries

the oxydant

oligomers,

Clays

is

Oxygen

cation

oxygen

by t h e

coordinated

when t h e e x c h a n g e

i n smectite

serves

of

cations,

was o b s e r v e d

benzidine

high

and regeneration

and d i m e t h y l a n i l i n e

only

and diphenoquinones

reactive

Redox

earth

place

-montmorillonites

color

(Equation of

with

very

was e x p l a i n e d

reactions.

(50)

however,

p-benzoquinone Cu

reaction

smectites

required,

This

at

on montmorillonite

a yellow

The p r o t o n a t i o n

or alkaline

presence

diols

acid).

presence

of

conditions)

the d i s s o c i a t i o n

1

the oxidation

number

i n reactions

spectroscopy

the c l a y ,

H" " i s

on B r ^ n s t e d

shifts

not

of

was o b s e r v e d .

source

tion

Fe(III)

by Mossbauer

intercalation

Upon

if

structural

demonstrated

p-menthene

were

with

the main

the a c i d i t y

species. i s an

The

example

products. of

the c l a y and

T h e mechanism was n o t

established,

however. Oxidative

Polymerization

tion

of

unsaturated

free

radical

electron

the clay

be

formed

or

or,

an aromatic react

cally

very

oligomers The

the organic

similar, (dimers,

site

is

compound

aromatic

species. trimers) indicated

scheme,

of

of

because

t o form

Repetition i n Figure

an acceptor

of

1 is

through for

acid +

e

,

a

of

site

w h i c h may

the organic

can attack

and, eventually, phenols

from

R

com-

a double

as an e l e c t r o p h i l e .

stable

A

a proton and

cation,

an electron

ring

polymeriza-

mechanisms.

to t h e Lewis

radical

the c l a y ,

relatively

radical

by l o s s

i n t h e same manner

polymerization

to this

of

of

can i n i t i a t e

free

a free

transfer

acid

another

mechanism

catalyzed cording

ring

formed

with

may b e f o r m e d

from

by e l e c t r o n

Clays

through

alternatively,

to the Lewis

intermediate can

which

e

transfer

of

pound

R ,

Reactions.

compounds

bond

The

resonance,

larger,

but

the process

but

chemi-

can

produce

polymers. postulated radical

for

the

cations.

one e l e c t r o n ,

such

as

clay-

AcCu(II)

22.

or


Fe(III),

presence would

must

of

0

result

be p r e s e n t

i n Figure

This

clays

as hosts

ever,

similar

phenol

(49, try

of

was

dimers,

trimers,

(non-analyzable

conducted

phenol

from

a

et

(55)

proposed

a l .

phenoxy or

the ortho

and

et

and

II VO

also

subjected of

(47)

identified

resonance

exposed

to water

were

inside

of

of

reaction

spectra.

c a n be

was

was

cations

were

-montmorillonites

Isaacson phenols

the products

a n d Sawhney

and s m e c t i t e

transition

metal

with

of

(60)

different

studied

exchangeable

complexes

showed

sorbed

phenols.

The t r a n s f o r m a t i o n

extent

i n clays

non-transition al.

(61)

dried of

with

studied

mers,

cations

decreased Wang e t

mixture

of

with

quartz

phenolic

and quinone-type had an e f f e c t

i n the order a l .

(62)

caffeic

acid,

vanillic

contained

acid, acid,

orcinol,

basis was and

biphenyl and

+

(10, a

)

and n o n -

of

number

the

50°C.

The n a t u r e

the

et

on a i r A

into

and

with

Sawhney

2,6-dimethylphenol

sorption

the

greater

i n those

transformed

of

clay-

transformed

study, at

11).

of

portion

dimers, of

t r i -

the

transformation

A l > Ca > Na. the oxidative

i n aqueous

and k a o l i n i t e ,

3:7 r a t i o ,

compounds

acid,

reported

compounds

illite, in a

than

compounds.

on both

Fe »

+

cations

complex

t o a much

C a - , A 1 - , and Fe-smectite was

Fe

studied

cations

of

à \

was

on the

length

,

subsequent

the polymerization

phenolic

morillonite,

metal In a

with

(Cu

occurred

n

poly(p-phenylene).

IR s p e c t r a

the clays

2,6-dimethylphenol

tetramers,

exchange and

cations.

Na-,

the adsorbed

a l l

transition

metal

homoionic

that

a

re-oxidized

the reactions

cations.

phenol

to

chain


I

on Fe

conditions

mineral

a n d Ru

gave

were

(49).

poly(p-phenylene)

cation

para

benzene,

benzene

the dry clay-polymer reduced

the

in

on type

When

of

Soma

experiments

dehydration

poly(p-phenylene)

p-terphenyl

exper-

by t h e

either

and a n i s o l e

reaction

-

The

substrate

study

the

Cu

at

these

the c l a y

the interlayer

polymers

to c r y s t a l s

observed

product.

conditions,

When

of

weight

initiated

also

but

under

of

spectrome-

present. clay

toluene,

polymeric

complex

by mass

a ?2^5 d e s s i c a t o r .

spectroscopic

hectorite

of

also

the organic

benzene,

dehy-

formed

the presence

may a t t a c k

with

under

were

molecular

The

of

enzymes,

2

smectite-phenol Analysis

systems,

i n their

vapor,

of

How-

i n the

Mn0 ,

2

is

the r o l e

-smectite

freeze-dried

i n the interlayers

Raman

2

indicated

radical

the clay

forms

t h e same

-

Polymerization

the formation to

Cu

polymerization

formation

exchange

+

noted

were

al.

complex

clays

oxidant

promoted H 0 ,

>

rationalof

properties.

products

but higher

and phenol

Pinnavaia

2

o r Cu

cations.

container,

position.

by r e f l u x i n g

may b e

weight

spectrometry)

that

benzene-anisole

-

the fresh

The phenoxy

conducted type

on Fe

molecular

by e x p o s i n g

different

radical.

suitable

redox

as 0

chromatography

by mass

were

and t h e i r (such

and tetramers,

iments

scheme

systems

1 and 2 i n d i c a t e

reactions

radical

and g e l p e r m e a t i o n

a

In the

which

(59).

of

of

where

i n Figures

adsorbed

ESR s p e c t r a

2.

i n reduced

(58),

cations

higher

formation

phenols

oxidants

extracts)

phenol

55).

shown

coupling

a number

conditions,

of

aquifers

for metal

cell-free

indicated

form.

shown

stability

and anaerobic

When

to

i n t h e scheme

The schemes

dration

cation

reoxidized

57),

and

the r a d i c a l

c a t i o n may b e

(54,

of

469

Reactions

metal

the apparent

presence

for

Organic

the reduced

2

izes

lacking.

Abiotic

each

of which

a n d by q u a r t z gallic ferulic

acid, acid,

and p - h y d r o x y b e n z o i c

polymerization

solution alone.

had been

p-coumaric The

a

mont-

mixed

The mixture

pyrogallol, acid.

of

containing

of

protocatechuic acid,

syringic

oxidative


470

OH

R°

_ 0 H

R?

H

_0H

OH

R

OH

H

-Η

C

R

U

(

I

I

^ ,

>

- H

H

H O - ^ - ^ O H R

OH

OH

» POLYMER

• TRIMER Figure

1.

Postulated

polymerization

mechanism

of phenols

for the clay-catalyzed

through

radical

cations.

Cu(ll)[clay]

Cu(l)[clay]

POLYMERS

2 0 ^2H 0 2

Figure

2.

aromatic and

Schematic compound

the formation

(Reaction B ) .

2H 0 0

2

2

representation

to 0

2

with

of polymers

2+

Β

2

of electron

a Cu-exchanged (Reaction

clay

transfer

from a n

as the catalyst

A) and hydrogen

peroxide

22.


polymerization of

"model"

resembled the

Reactions

was to

ring

found

being

either

o r the nonbonding with

t h e amino

nite,

possibly

(28)

showed

exchangeable

v i a the formation

that

when

through

a sand

and spots

developed

complex

formation

between a n i l i n e

II

column c o n t a i n i n g

complex

some

along

was c o n f i r m e d

in

natural

structural Soma pound

systems,

e t a l . (12) have

polymerization

ization

potentials upon

exchanged

benzenes sorbed,

number

than

(1)

II of the

The f i n a l reactions

could

have

of organic

(2)

compounds

the presence

of

of exceptions

that

9 . 7 eV f o r m g

com ion

radical

benzenes

and prevented position,

biphenyls

which

sites.

coupling

are

stably

polymerized, and are nonreactive

However,

d i d not f i t this

and b i p h e -

from

monosubstituted

(3)

and anthracene

to reaction

with

of transition-metal i o n -

and p - t e r p h e n y l

naphthalene,

access

f o r aromatic

compounds

parasubstituted cations

of the para

biphenyl,

methane,

the trends aromatic

approximately

to 4,4'-substituted

to hindered

Such

conditions,

i n the interlayer

as the r a d i c a l

(4) b e n z e n e ,

(5) b i p h e n y l due

lower

due t o blockage react

colored

type

The presence

i n aqueous media

generalized

montmorillonites,

reactions

et a l .

percolated

indicating

polymer.

aerobic

as follows:

adsorption

a r e sorbed

was

ubiquitous.

+

cations nyls

under

to

montmorillo

b y IR a n d E S R s p e c t r o m e t r y .

complexes

found

reacted Cloos

(64).

solution

Fe

was

Wyoming

for the transformations

where,

F e ^ is

with

and the c l a y .

type

smectite

Cu

+

through

II

cations

of the aro

Fe^ -montmorillonite,

was a s o i l - h u m i n o r k e r o g e n - l i k e implications

whereas

the column,

product

important

polymeriza

of the amino-group.

heated

aniline

stripes type

pair

o f N-N bonds

an aqueous

that a l l


the π-electrons

T r i p h e n y l amine

(63). when

showed

mixture

which

catalyst.

electron

group

of

the oxidative

the π-electrons,

NjNjN'N'-tetraphenylbenzidine

i n a dark

spectra

The r e s u l t s

catalyzed

interaction with

to interact

coordinate

and r e s u l t e d

products.

with

471

Reactions

the infrared

t h e weakest

of aniline

may b e t h r o u g h

acids,

and the quartz

quartz

Organic

immediately

of natural

minerals

with

matic

place

humic and f u l v i c those

clay

tion,

took

Abiotic

scheme

they

observed

and these

a

were n o t

explained. Bronsted A c i d i t y

of Clay

primarily

from

arises

exchangeable

cations

[Μ(Η 0) ] 2

This cations, clay

tends

the strength

the structure

_

1

)

+ H

+

(9)

+

and charge

of the

i t s polarizing

power a n d ,

of the adsorbed

montmorillonites

i n the order

A l > Mg > N a ,

structure

to cations

of the

and t h e smaller the

o f a c i d i t y may a l s o

water

a n d t h e number

of the clay

clays to

and pretreatment

of homoionic

and the clay

i n bulk

η

of dissociation

and the order

coordinated than

(

the charge

the higher

acidity

content

of water

t o be s t r o n g e r Both

on

acidity

1

on the s i z e

the higher

cation,

χ

and t h e type

Na, Mg, and A l decreases

by the moisture

Dissociation

depends

the degree

the surface

of

coordinated

65):

content,

the higher

the reactive

enced

o f water

2

Generally,

with

T h e Bronsted a c i d i t y

[Μ(ΟΗ)(Η 0) _ ]

+

Bronsted a c i d i t y

Thus,

saturated but

η

o f t h e exchange

therefore, water.

(6, 36,

the moisture

system.

radius

χ

Minerals.

the dissociation

be

influ

(65, 66).

i n the interlayers

(65).

o f t h e Bronsted

and i t s pretreatment.

sites

The acid

depend


472

strength number alent

dry

0.04

and

>

is

(39).

As

>

water, a

a

the

(67). If

IR

the

Lewis

electrons

and

as

HF/SbF^

groups

tetrahedral an

associated

of

protons Table

catalyzed in

III

lysts,

to

Br^nsted

varies

fully that

sis

or

a

by

using of

ing

Solomon

substrate

to

a

of

clay have

of

1%)

residual

evacuating (100-500°C)

of

that

at

1%

acidity.

is

exhib-

adjacent

properties been

The

of

a

by

the

2:1

A l

+

,

with

capacity,

two

substitution

Si

),

a

layer.

acid

layer.

perhaps

one When place asso-

takes

place

is

(69)

associhas

shown

activity

In due

adjaiso-

are

proton

Davitz

catalytic

of

takes

protons

is

contrast, to

of

no

layer.

charge

to

strength

presence

clays

lower 3

attributed

acid

octahedral a

for the

parameters The of

as

or

octa-

shielding

of

acid-,

or

of

chemicals hydroly-

in

of

biological

markers

(22-24)

catalysts can

initiated

be

(34,

found

in

the

36).

context or

of

dia-

chemical

Mechanistic

the

inter-

comprehensive

(37). by

reactive

protonation intermediate.

decreasing acid.

and

representative

hydrolysis

(73),

lists

by

base-catalyzed

the

with

triazines

tempercata-

IV

promoted

with

the

high

Table

be

along

with

at

industrial

studied

Hawthorne

conjugated

surfaces

to

acid-

been

have

be

a

as

temperatures.

concerned

Br^nsted conditions

dehydration

suggested

(70-72),

affect

reaction

minerals

ambient

and form

of

extreme

neutral,

of

that

range

clay

mineral

reactions

decreases the

at

been

probe

clays

such may

pK

the

inactive,

shown

reactions

Reactions protonation

by

by

(
higher

extreme

are

substituted

the

the

conditions of

by

adding

water

species

and

reversible

montmorillonite to

the

order

system

amines

esters,

to

groups

the

to

of

the

of

of

a

The

(Equation

l

c

o

n

° l

bonds to

>

may

dehydration

carbonium

unsubstituted

reaction

s

hydrocarbons

lead

corresponding

77).

a

>

double

may

formation

transformation

(76,

> ^i"^2

ethers

protonation

hydroxyl

triphenylcarbinol

bonium

medium

alcohols,

Protonation

protonated

Examples

of

decreases

> ketones

occur of

of

ion.

and

triphenylcarcan

be

reversed

by

10):

OH (10)

Hydrolysis

Reactions.

single

bond

(78).

The bond

atom

(C

atom

(0,

in

promoted,

by

is

Br).

conditions,

such

Ρ in

The

depending as

with

typically

carbonyl,

CI,

Hydrolysis

reaction

on pH,

a

may b e

temperature,

and

neutral,

properties and

ionic

cleavage

or

between an

organophosphates) substrate

involve

hydronium,

polarized

reaction the

reactions

water,

a

of

hydroxide

a ion

electron-deficient

an

electron-rich

base-, and

the

strength

or

acid-

reaction (78,

79).

22.


Table

IV.

Organic Clay

Abiotic

Reactions

Organic

Affected

475

Reactions

by S u r f a c e

B r ^ n s t e d - A c i d i t y of

Minerals References

Examples

Reaction Démetallâtion

of tin-tetrapyridyl-porphyrin

organometallic

by

compounds Hydrolysis

Η , Μ, Β

of

carboxyl acid

esters

ethyl

epoxides

acetate

cyclohexene

stituted

(74)

by M a n d Κ

oxide

and s u b -

2,3-epoxypropane

by Μ, Κ t o

(74)

glycols N-methyl-p-tolyl

carbamates

carbamate

b y Μ, Κ t o c r e s o l a n d

(73)

methyl-amine alkyl

isopropyl

halides

bromide

N-heterocycles

s-triazines

organophosphates

parathion,

phosmet

(69,

by Κ and M

Hydrogen Exchange aromomatic

detritiation

NH^ s a l t s

naphthalene

(23)

of

of

boxylic

ammonium a c e t a t e

car

by Β t o

acetamide

acids

d>

F o r m a t i o n by

dehydration

cholestanol

of

to

alcohols Addition

to Double

by Κ and M

cholestene

22, 34, 35)

Bonds of

water

to ethylene

alcohol to

of

by Β

Condensation

acetic

methylparathion

71)

of

hydro

carbons

Alkene

(74) (73) (71)

b y Μ, Κ

by M

by M t o

ethyl

(81)

acid

to 2-methylpropene

by A l - B

(75)

2-methyl-propyl-2-acetate

Double

Bond

Isomerlzation

alkenes

in

limonene

(20) (26)

by M

sterenes Ketal Formation c y c l i c ketones Al-B

from cyclohexanone

to dimethyl

9.

Rearrangments

10.

Dimerization

diamerization fatty

of

cholestanol

dicarboxylic

acid

formation

from u n s a t u r a t e d

fatty

propenylbenzenes

alkenes Polymerization

of

sugars M:

acids

(1) (33)

(38)

styrene Inversion

(22)

of

2-butene

12.

(75)

of

acids

11.

by

of

sterols unsaturated

and methanol

ketal

montmorillonite;

sucrose K: k a o l i n i t e ;

(80)

by H - B +

H: h e c t o r i t e ;

B:

bentonite.


476

Both

acid-

surfaces

and

base-promoted

and,

acidity.

hence,

Kinetic has

died

hydrolysis

They n o t e d

been

that

catalytically Rate tions

to

for

have

demonstrated

reviewed

the

is by

several

(neutral,

that

bromide

acid-,

in

oxide between and

due

slight

to

cant

increase

strongly

sorbing

For neutral

the

of

aqueous

same

the

3

of

triazines) extremely ments et

and

+

(73).

(73)

at

in

these

the

in

6N H C 1 , a n d

to

4 units

sted The room

no

it

lower

-> C 0

2

in

that

was

the

at

and

25°C

isopropyl

kaolinite.

found

no

clay-

ethyl

effects

acetate,

were

because

less

polar

For

significant

(wt/wt)

For

probably a

and

signifimore

susceptible

rates

slower

than

explanation hydrolysis

of

to

hydrolysis

in

aqueous

is

the

on

solu-

lower

mechanism

pH

at

in

that have

increases the

+

2

CH NH 3

was

(12)

in

acidity

of

these

in

control

surface

with

pH a t

the the

of In

products surface. clay

Russell were The

spectra

was

experi-

IR

obtained

surface

was

suspension. evidence

decreasing

by

clays

solution.

silicate

the

(hydroxy-s-

observed

kinetic

with

promote

analogs

aqueous

the the

presented

complexes.

(11)

2

hydroxy

agreed

that

demonstrated

tetrapyridylporphyrin

3

hydroxy-s-triazine

measured

acidity

at

— O C ^ C h ^

> CH N=C=0 +

the

form at

studies

is

the

surface

complexes

inferred

than

acidity

chemical

homogeneous

the

protonated surface

to

degradation

surface

temperature

rates

homoionic montmorillonite

Several extreme

substrate

+

H 0 of

pH 3 . 5

suggested

spectra

a

following

Apparently, since

stabilized of

+

NH^ forms

conducted

al.

if

l-(4-methoxyphenyl)-

surface

the

were

chloro-s-triazines

high,

for

A possible

H

H

the

characteristics

4.5%

small

_ -> C h ^ N C O O C ^ C ^

3

The

at

clay

carbamate,

The

CH N=O0

hydrolysis

if

works

proposed:

OH" CH NHC00C H CH 4

they

decomposition,

pH.

(74).

s o l u t i o n was

6

The

and k a o l i n i t e

bulk

surface

3

promoted

oxide,

buffers.

observed

base-promoted

the

clay

diffi-

l-(4-methoxyphenyl)-2,3-epoxypropane.

Na-montmorillonite tion

was

soluto

studies

hydrolysis

including

determined

found.

N-methyl-p-toluyl and

the

bromide,

homogeneous was

effect

data

Several

occur

hydrolysis

cyclohexene

limited i n t e r a c t i o n with

promoting

aqueous

other

m o n t m o r i l l o n i t e and/or

rates

in

the

remains

are

and

explain

these

surfaces

stu-

surface.

may h a v e .

reactions

determined different

isopropyl

the

those

of

clay

sucrose.

not

clay

at who

(74).

acetate, of

did

homogeneous

(70-74;

base-promotion),

and

suspension

mineral

sorption

surfaces

(74)

ethyl

of

i n h i b i t i o n may a l s o

with

and

difference a

but

suspensions

cyclohexene

only

8),

in

acidity

inversion the

acidic

surface

(80)

application

involving

clay

and M i l l

2,3-epoxypropane,

but

acid-catalyzed

at

substrates

the

by

the

Coleman

pH m e a s u r e m e n t s

effects

base-promoted

El-Amamy of

and

reactions

(79),

unknown

sorbed

is

Br^nsted and

hydrolysis

Theng,

hydrolysis

increased McAuliffe

H -concentration at

conditions

due

affected

influence

by

ethylacetate

reviewed

cult

substrate

of

may b e

which

for

potentionmetrie

been

environmental

factors

presented

effective

data

have

reactions

the

evidence

surfaces the

by

air-dried

the

the

Br f i -

content.

montmorillonite

demetallation

contrast,

that

moisture

in

of

Sn(IV)-

homogeneous

at

3

22.

VOUDRIAS A N D R E I N H A R D

solutions

demetallation

100% s u l f u r i c face,

the

however,

Decreasing rates,

but

if

on Na-,

mined

by

remaining

rate

Increasing very

rate

the

in

of

the

Mill on

clay

(74)

a

the

even

clay

the

(70,

parathion

content the

2 and

further,

of

to

increase

decrease

hindered

of

almost

Similar

hydrolysis

to

in

the

the

the

hydrolysis

were

the

degra

resulted in

the

content

of

2%

limit

rate. by

first

of

content

chem

above

The

catalytic

reported

in

change

cation's

upper

water

kaolinite 0.8%.

2% w a t e r , Little

deter

percent the

about

exchange

completely

trends of

the

Moisture

the

11% c o r r e s p o n d s

A slight

versus

rate.

11.2% m o i s t u r e . water

the

of

The

were

of

Na-kaolinite,

up

degradation

with

methylpara-

a

content

to

and

4 is

water

due

74).

Figure

a

hydrolysis

71,

temperature

15 d a y s

to

(81).

room

shows

s l o w up

irre

at

plot

Weaker

conditions

reactivity

disappear

in

sur

are

acid-catalyzed

for

steep

the

similar

that,

surface.

for

absent,

may

(71).

whereas

water

free

under

after

water.

11% r e s u l t e d of

totally

saturation

at

demetallated.

figure

between

ence

not

organophosphates

in

possible,

is

on k a o l i n i t e

very

shell,

bound

not

present

increases

Al-kaolinite

moisture

to

content

al.

increase

occurred

corresponds hydration

The

was

sharp

ically

et

is

is

Fe(III)-tetraphenylporphyrin,

surface

the and

All

Reactions

complexes

much w a t e r

protonated

is

the

of

Ca-,

content.

dation

of

Saltzman

parathion

a

moisture

rates

thion

and

moisture

acidity

hydrolysis

water

such

too

such as

demetallated

Bronsted

of

If

Organic

Sn(IV)-tetrapyridylporphyrin

complexes, versibly

acid.

Abiotic

pres

effect

El-Amamy

and

l-(4-methoxyphenyl)-2,3-epoxypropane

Na-montmorillonite. A

qualitatively

hydrolysis order

to

the

than at

hindrance

conformation

rate

the

the

on

methoxy

group

force

the

favorable

for

to

methyl

compared

rate

of

molecule

was

on

that

of

On t h e

the

due the

the

ethoxy

a

was

(70)

that

hand, size

of

or

the

higher

smaller group

A l -

position

other

Al-clay

to

In

at

suggested into

the

4).

parathion

it

hydrolysis.

for

(Figure

parathion

probably

to

observed

surfaces,

parathion

(71),

was

Al-kaolinite

hydrolysis

Na-kaolinite

Na-clay as

relationship

on C a - and

lower

may

less

hydrolysis one

similar

parathion

explain

kaolinite steric

of

than of

the

parathion

(70). The sorbed

experimental

water

parathion.

Sorbed

or

groups,

hydroxyl

the

exchange

the

hydrolysis

of

exchange

cation at the

ligand

tions,

may

edge

the

reaction

P-0

associated

with

of

and

bond.

The the

polarize

the

water

and

Sanchez

or

as

oxygen

a

(70)

ligand showed

organophosphorous a

ligand

water

adsorbed by

the

and weaken Martin

influence

sites. Η0-Η

with

esters,

The bond

studied

the

the

catalytic

following

at

cations:

after

suspension to

hydrolysis

24 h o u r s of

30°C. Ca at

The m o n t m o r i l l o n i t e ,

Ba

pH 6 ,

, the

Ca-montraorillonite

3% i n h o m o g e n e o u s depended

on the

Cu

,

Mg

,

hydrolysis was

more

aqueous

exchange

was

and of

than

solution.

c a t i o n and

.

(70). reaction

in

with

decreased

in

the

found

aqueous

extent

of

by

was

60% c o m p l e t e , The

of

interac

hydrolysis

It

phosmet

an can

attack

saturated

Ni

in

of

moiety

cation-ligand

(72)

for

atoms

that

molecule

phosphate

the

that

sites

(o,o-dimethyl-S-(N-phthalimidomethyl)dithiophosphate)

montmorillonite

compared

that

suggest

surface

al.

reactive

enhanced

Camazano

phosmet

of

et

(71)

degradation

lattice,

other

which

factors

the

Mingelgrin

Sanchez

the

al.

be

attack

is

et and

blocking

molecule

Saltzman

adsorption

by

the

by

of

as

sites

Work

through

water

mechanism and

that

water

parathion,

occurs

inhibit

serve

cations.

general,

the

findings

molecules

as of the


478

order

C a ^ (60%),

B a ^ (40%),

Cu

z

(23%),

+

Mg

z

(14%),

+

and

N i

z

+

(3.2%). Experiments group but

of

different

hydrolysis exchange

+

the

,

charge,

It

tetrahedral

clay

was

interlayers,

The fission

to

hydrolysis of

attack

the P-S

a

that

the

It

montmorillonite

a l l

i n the

the highest

low

total

appears

charge

that

(total sites

was

due t o

may h i n d e r

the r e a c t i o n

of

or

with

the type

or to

Ca-form,

rate

charge

a

of

the

tetrahedral) the organic

the low r e a c t i v i t y

clays

which

that

the r e a c t i o n

postulated exchanged

+

compounds

nucleophilic

charge.

of

of

hectorite)

with

and the i n t e r l a y e r

a n d t h e Mg

organic

minerals

showed

to c l a y s

the a c c e s s i b i l i t y

(72).

of

nontronite,

layer

low

cation

control Ni

a series

corresponded

particularly

cule

with

(montmorillonite,

strong

of

mole-

t h e Cu

attraction

the i n t e r c a l a t i o n

of

, of

the

sites.

of

phosmet

of

an OH" group

i n a n aqueous

solution

takes

on t h e phosphorous

place

atom,

by

causing

bond.

(13)

The

catalytic

formation exchange of

of

cation

t h e P=S

increases tating

hydrolysis takes

group

of

the P-S

two s t a g e s ,

stage

is

rate

cations the

cases,

of

of

short

with a

the c l a y .

Addition

to Double

Br^nsted

acidity

elimination

is

very

where

R

water

from

be

f

may b e

(37).

accompanied

intermediate cyclic

Alkylamines

stage,

f a c i l i -

by o t h e r

montmorillonite

which

to

have

is

been

surfaces

c a n promote

Equation

14 s h o w s

catalyzed

a

constant.

function In

of

some

constant

of

stage,

most

the f i r s t reached

first

exchangeable

also

the h y d r o l y s i s

occurs

The

rate

and

constant.

the end of

of

(72). Both Lewis

and

a d d i t i o n and

an example

by Brrfnsted

f

an a l k y l

(dehydration)

for

an

acidity:

reactions, to

form

respectively thiols

+ R-CHOR -CH -CH 1

3

or an a c y l catalyzed such

as

mixtures

and i n t e r - m o l e c u l a r

and a l k y l

thus

kinetics.

charge

rate

2

proton,

products,

atom

interaction

producing

hydrolysis

the layer

R-CH -CH0R -CH

carbocation

intra-molecular and

a

the the

+

2R'-0H

alcohols

At

of

first-order

close

equilibrium H

+

2

and

and E l i m i n a t i o n Reactions.

mineral

reactions

2

of

i n the clay

Bonds

of

of

the sulfur This

phosphorous,

and has a h i g h

solution.

addition/elimination

2R-CH -CH=CH

of

i n the presence

apparent

The second

sites

through

the OH" group

h a s a much s l o w e r

i t s magnitude

accessible

by

the result

t h e O=0 g r o u p .

character

function

parameters, i n aqueous

of

is

interaction with

bond.

duration

as

i n which

simultaneously

attack

phosmet

both

varies of

same

phosmet the

place

the e l e c t r o p h i l i c

Hydrolysis

The

complex,

and t h e oxygen

the n u c l e o p h i l i c

hydrolysis in

by m o n t m o r i l l o n i t e

a bidentate

group.

by

isomeric

may u n d e r g o

to

of

the

alkenes,

form

oligomeric

and p o l y m e r i z a t i o n similar

(14)

a c i d i t y may

rearrangement of

3

E l i m i n a t i o n of

surface

dehydration

(75),

2

(37).

e l i m i n a t i o n and

22.


condensation as

H 0 with

reactions; alkenes

2

for

82). in

double

For instance,

the presence

Ion-exchanged of

ketals

methanol of

of

at

to b o i l

clay

ketal

reaction

(37)

suggest

in 5 min.

petroleum

When

Reactions. reactions

tions were

exchange

between observed

been

and other

give

caused

yield

of

Al-bentonite

may h a v e

to

On a d d i

and t r i m e t h y l

reaction

deuteration)

observed was

surface of

the

the

is

used,

Hawthorne

involved

organic

in

sediments

(23)

and a l i p h a t i c

and naphthalene homoionic alkyl

groups

to r a t i o n a l i z e

reac

derivatives

bentonites

exchange

temperatures

A mechanism s i m i l a r

invoked

a c i d i t y may p r o m o t e

Hydrogen-exchange

hydrogen

between

at high

or Lewis

Both aromatic

In c o n t r a s t ,

(670 h ) .

substitution

with

time.

Solomon and

reported.

slurries

or

were

has been

i n aqueous

detritiation times

Bronsted

clay

(70°C).

tion

of

formation

temperature

quantitative

(75).

lipid

(37).

the a c i d i c

temperatures surfaces

of

for

deposits.

hydrogen-exchange hydrogen

place

a t 18°C

(75).

reacted

reaction

to

(75,

acid

product

cyclohexanone

elimination reactions

Hydrogen-Exchange (24)

of

Na- instead

transformation

acetic

the exothermic

i n an almost

d i d not take

that

geochemical

into

30 m i n o f

acids

with

room

75).

effective

conditions

catalysts

at

fashion

(37,

mild

Cyclohexanone

the mixture

and r e s u l t e d

the the

to

t o be

the ester

Al-bentonite after

thiols

and c a r b o x y l i c

efficient

room-temperature,

dimethyl same

of

shown

reacted form

or ketones.

dimethyl ketal

t h e same

to

are also

aldehydes

been

relatively

2-methylpropene

in a similar

and a l k y l

alcohols,

under

Al-bentonite

i n the presence

orthoformate liquid

of

of water,

bonds

bentonites

from

33% y i e l d tion

2

have

479

Reactions

alkylamines

bentonites

addition

carbon-carbon

Organic

NH3 and H S can r e a c t

to form

Cation-exchanged catalysts

Abiotic

at

low

(measured

and a c i d i c

(160°C)

and long

to e l e c t r o p h i l i c the aromatic

as

clay reac

aromatic

H-exchange

reaction. The mechanism o f a

possible

a

Lewis

alkyl

acid

site

may h a v e

cies

followed

by exchange

nism

predicts

exchange

adjacent This of

is

to

t h e most

consistent

steranes

The

hydrogen

of

stable

of

Soil

Organic

soil

may c o m p e t e

gether.

In s o i l s

rates and, the

on h y d r o l y s i s

of

moderate may b e

by s o r b i n g

organic

matter.

tion

decreased

This


for

for

of

β-carbon.

of

Humic compounds organic

smaller humic

with

the parathion

the organic Yaron

an i n c r e a s e

sites

matter

than acid

(84)

into

>

3° > of

mecha

2°

>

(83).

content, with

i n the

them

alto

catalytic low

reduced

by c o a t i n g

organic

hydrolysis the

surface

the l i p o p h i l i c phase

i n the s o i l

that

parathion

organic

the reactive

1°).

epimerization

present

in soils

by

spe

groups

or block

to clay

showed

to i n a c t i v a t i o n of

decomposition.

rates

sediments

reaction

Such a

at methyl

(benzylic

l-(4-methoxyphenyl)-2,3-epoxypropane

perhaps, soil

Matter.

The a d d i t i o n

a

but

abstraction

a carbocation-like

relative

maturation

or

(74).

at

hydride

preferentially

carbocations

Role

effects

forming

the observed

thermal

with

Partial

a proton

to occur

with

during

occured

sediment

matter

e x c h a n g e was n o t c l a r i f i e d ,

m e c h a n i s m was p o s t u l a t e d .

matter sites

of

degrada content. available


480

Oxidation

of

Organic

Certain

Mn(IV)-

organic

compounds

are

ubiquitous

transforming for

some

(i.e., the

Compounds

and F e ( I I I ) - o x i d e s (14,

16).

i n earth

organic

metal

by O x i d e s

oxides

a c t as Lewis

materials

is

acids).

product

(15, 86), an effect

tain

enzymes

(87-89).

nitrogenous (measured

ture

of

and a

previous of

were

shown

study

aromatics

were

to a

als

results

oxides

buffer tion

cations or clays

such

as Fe

Mn0

was t h e m o s t

no

natural exists water sibly,

effective

oxides,

c a n be

polymeriza minerals

(19).

Olivines, reaction

tephroite, formula

to

2

was

4

a

manga

M^SiO^. effective,

i n water

as

dismutates with

sediments,

as a

(Μη

phenols

of

soluble

of Mn0 , 2

oxygen

shown

i n Figure

5.

to produce dissolved

0

2

*00H,

and hydrogen

or adsorbed

transi

whereas

In

of

as

incapable

compared

and Huang

were

radicals,

*00H.

0 · 2

sites

pK

phenol.

a

of

Dilute

These

i n

species

H 0 , 2

but

ratio

4.75 and

Either

peroxide,

of

to

(15),

reactions

has a

ions,

general,

hydroxyl

and Fe

anion

of

The e f f e c t

adjacent

hydroperoxyl

radical

phosphate


by Shindo

dissolved formed,

i t .

b u t i t was f o u n d

from

stream

Addition of

polymerization.

activity

In

the presence

The p o l y m e r i z a t i o n

superoxide

).

brownish-green

polymerization,

without

reported

radical

Fe

to

and

transition

to a dilute

of

materi

pyrogallol, clays,

,

catechol

of

and H u f n a l

to h u m i c - l i k e

t h e pH r e d u c e d

catalytic

formed

by L a r s o n

polymerization.

promoted

was a l s o

hydroperoxyl

react

freshly

primary

(Fe Si0 ),

compared

catalyst,

of

was g i v e n .

silicates,

The

for

catechol,

because

the rate

by a mechanism i n v o l v i n g

radicals

of

when

of

, which

The s u p e r i o r

nalized

as

of

by c o m p l e x a t i o n

polymerization

explanation

A l

although

M i c r o c l i n e and quartz

previously

c a n promote

lowering

a n d Μη

metal

some

chemical

such

pH, probably

increased

explained

groups.

>

pH 6 ( 1 5 ) . of

than

struc

polymerization,

polymerization

transformation

which

E D T A was

other

at

the polymerization

analog

reported

was i n c r e a s e d

o f EDTA o r

2

hydroquinone

hydroquinone

ZnO, CuO) a n d c a t i o n s

2

of

addition

promoting

Fe(II)

compounds,

comparable

metal

The

polymer

on the

impurities

was g r e a t e s t

the ideal

i n the presence

(Mn0 , rate

products of

sediments

with

were

organic

metal

polymer

(16).

promoting

time

and f e l d s p a r s .

the oxidative

derivatives, the

cer

extent.

their water,

accelerated

the corresponding

model

metal

acid

with

6 0 0 n m ) , much more

and F e ( I I I ) - o x i d e s ,

The e f f e c t

who s t u d i e d of

that

formed

depended

promote

polymerization of

silicate

lesser

Similar (14)

reaction

observed

at

at

may i n d u c e

to a humic

to the r e a c t i o n

i n the order

7 days

than micas

ineffective.

Fayalite, but

to Mn(IV)-

extent

nese-bearing

absorption

action

molecules

hydroxylation and, presumably,

and amphiboles

greater

effective

of

organic

(13).

to promote

pyroxenes,

to that

polymerization

has i n d i c a t e d

may p r o m o t e

Similarly

a

for

abiotically

Mn(IV)-oxides

a n d ammonia were

and decreased

in

T h e mode

from

was a d d e d

did not significantly

silica

tion

of

role

compounds

similar

were

increased

> catechol,

Si-oxides

ground

as

phenolic

glycine

studied

The r a t e

the phenol

resorcinol

When

polymers

ization

Fe(III)-oxides.

electrons

of

and Mn(IV)-oxides

important.

F o r example,

like

Mn(IV)-oxides

their

Minerals

the oxidation

Fe(III)-

(85),

to accept

polymerization of

various

both

may b e

oxidative

mixture,

c a n promote

Since

compounds

and Primary

or,

2

H 0 2

2

in pos

does

22.


Abiotic

Organic

481

Reactions

Moisture content CM Figure the 1976

4.

clay

Degradation moisture

American

Figure

5.

from

clay

a

Copyright

Chemical

Formation surface

American

of

parathion

content.

of

on k a o l i n i t e

(Reproduced

from

Ref.

as

a

71.

function

of

Copyright

Society.)

hydroperoxyl

to d i s s o l v e d Chemical

radicals

oxygen.

Society.)

by e l e c t r o n

(Reproduced

from

transfer Ref.

14.

482


Figure

6.

radicals

Reaction (after

Ref.

scheme 90).

for

the

attack

of

phenol

by

"OH

22.

Abiotic


not

attack

ble

cations,

to

form

catechol

rapidly

in

their

hydroxyl

or

hydroperoxyl

H 0 2

2°2 +

2

+

M

(

n

μ

Π

+

+

1

)

The

*0H c a n

addition

to

the

react

The

oxygen

eventually

to

according

to

latter the

and

Abiotic

organic

tion,

clay

clays

+

"

>

0

H

0

+

catechol, to

~

H

,

by

0

with for

M

+

H

0

(

n

+ M

+

H

+

+

n

other

)

(15)

+

(16)

+

( ) 1 7

abstraction

or

resonance-stabilized catechol

highly

phenol

1

2°

H

the

reduci

reaction):

hydrogen

produce

couple

proposed

(Fenton

*00H +

polymerized,

can

act

cations

can to

as

The

molecules

colored

by

sites

result,

reactions

solved als

with

some

or

materials,

Voudrias

(90)

Brrfnsted produce

(Fig

many

of

the

solutions.

merits

to

ring-containing If

oxygen

is

exchangeable

acidities

neutral

formed

humic

from

that

rates

under

as

the

addition,

Base-catalyzed not

the

oxidative

influenced.

between

general,

occur

in

selectivity

polymer

products,

reaction

environmental

the

surface.

are

In

also and

clay

acid-like

the

cations

content,

hydrolysis,

promoted.

silicates.

reactions

at

promote

to

catalyst.

moisture

reactions

can

phenols in

such

are

com

present,

a

low

of

radical

to

minerals

predict

from

as

At

re

on

formation

act

However,

further

aromatic

reactions,

sites

+

to

coordinated

exchange,

and

lead

Aromatic

polymers.

surfaces been

cations

electrons

may

substitu

the

have

metal

cations.

and

by

oxides

accepting

acidity.

*0H r a d i c a l s 2

metal

transfer

extreme

substituted F e

by

or

elimination,

influenced

transition

other

water

primary

and

and

reoxidized

of

inhibited

difficult

problem

be

are

radical

trimers,

hydrogen

through

promote and

may

and

oxygen

oxidant

ent

in

and

are

of

or

acid-catalyzed

oxides

probably

can

sites

electron

further

dimers,

clay

elimination,

ization

acid

This

react

hydrolysis,

exchangeable

Lewis

results

Br^nsted

Metal

or

dissociation

clays

as

which

minerals,

complexes

form

reduced

a

primary

compounds. transfer

pounds

such

polymerization

Structural

charge

the

reactions

and

minerals,

organic

or

scheme

H

or

decomposed

Conclusions

redox

viewed.

As

form

0

oxidizable

catalytically

6).

Summary

of

->

ring,

could

"

>

+

with

of

is

radicals

2°2

aromatic

radical.

—

it

483

Reactions

absence

presence,

2 H

of

the

but

H

ure

in

Organic

clay

dis

miner

homogenous may

be

acid

differ

conditions.

This

study.

Acknowledgment s This

w o r k was

through 01-0.

the

supported

R.S.

However,

Agency's

peer

Kerr this

and

the

U.S.

publication

administrative

necessarily

reflect

ment

be

should

by

Environmental

Environmental Research

the

inferred.

views

of

has

not

review the

been and

Agency

Protection

Laboratory, subjected

therefore and

no

Agency

CR812462to

the

does

not

official

endorse

GEOCHEMICAL PROCESSES AT MINERAL SURFACES

484

Literature Cited 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31.

Weiss, A. Angew. Chem. Int. Ed. Engl. 1981, 20, 850-60. McBride, M.B. Clays and Clay Minerals 1979, 27, 224-30. Comejo, J; Hermosin, M.S.; White, J.L.; Barnes, J.R.; Hem, S. L. Clays and Clay Minerals 1983, 31, 109-112. Lasaga, A.C. Reviews in Mineralogy 1981, 8, 1-68. Mortland, M.M. In "Agrοchemicals in Soil"; Banin; Α.; Kafkafi, U., Eds.; Pergamon Press: Oxford, 1980, pp. 67-72. Yariv, S.; Cross, H. "Geochemistry of Colloid Systems"; Springer Verlag: Berlin, 1979. Boudart, M.; Djega-Mariadassou, G. "Kinetics of Heterogeneous Reactions"; Princeton University Press: Princeton, NJ; 1984. Theng, B.K.G. In "International Clay Conf."; Van Olphen, H.; Vaniale, F., Eds.; Elsevier: Amsterdam, 1982, pp. 197-228. Soma, Y.; Soma, M.; Harada, I. Chem. Phys. Letters 1983, 94, 47 5-8. Soma, Y.; Soma, M.; Harada, I. Chem. Phys. Letters 1983, 99, 153-6. Soma, Y.; Soma, M.; Harada, I. J. Phys. Chem. 1984, 88, 3034-8. Soma, Y.; Soma, M.; Harada, I. J. Phys. Chem. 1985, 89, 738-42. Schofield, P.J.; Ralph, B.J.; Green, J.H. J. Phys. Chem. 1964, 68, 472-6. Larson, R.A.; Hufnal, J.M. Limnol. Oceanogr. 1980, 25, 505-12. Shindo, H.; Huang, P.M. Soil Sci. Soc. Am. J. 1984, 48, 927-34. Shindo, H.; Huang, P.M. Nature (London) 1984, 308, 57-8. Stone, A.T.; Morgan, J.J. Environ. Sci. Technol. 1984, 18, 450-6. Stone, A.T.; Morgan, J.J. Environ. Sci. Technol. 1984, 18, 617-24. Shindo, H.; Huang, P.M. Soil Science 1985, 139, 505-11. Frenkel, M.; Heller-Kallai, L. Org. Geochem. 1977, 1, 3-5. Johns, W.D. Ann. Rev. Earth Planet. Sci. 1979, 7, 183-98. Sieskind, O.; Joly, G.; Albrecht, P. Geochim. Cosmochim. Acta 1979, 43, 1675-9. Alexander, R.; Kagi, R.I.; Larcher, A.V. Geochim. Cosmochim. Acta 1982, 46, 219-22. Alexander, R.; Kagi, R.I.; Larcher, A.V. Org. Geochem. 1984, 6, 755-60. Aizenshtat, Z.; Miloslavsky, I.; Heller-Kallai, L. Org. Geochem. 1984, 7, 85-90. Brassell, S.C.; McEvoy, J . ; Hoffman, C.F.; Lamb, N.A.; Peakman, T.M.; Maxwell, J.R. Org. Geo. Chem. 1984, 6, 11-23. Tannenbaum, E.; Kaplan, I.R. Geochim. Cosmochim. Acta 1985, 49, 2589-2604. Cloos, P.; Badot, C.; Herbillon, A. Nature 1981, 289, 391-3. Wang, T.S-C.; Chen, J.-H.; Hsiang, W.-M. Soil Science 1985, 140, 3-10. Mortland, M.M.; Lawless, J.G. Clays and Clay Minerals 1983, 31, 435-9. Adams, J.M.; Ballantine, J.A.; Graham, S.H.; Laub, R.J.; Purnell, J.H. Reid, P.I.; Shaman, W.Y.M.; Thomas, J.M. J. Catal. 1979, 58, 239-52.

22.


Abiotic

Organic

Reactions

485

32. Adams, J.M.; Clement, D.E.; Graham, S.H. J. Chem. Res. 1981, 254-5. 33. Adams, J.M.; Bylina, Α.; Graham, S.H. J. Catal. 1982, 75, 190-5. 34. Adams, J.M.; Clapp, T.V.; Clement, D.E. Clay Minerals 1983, 18, 411-21. 35. Adams, J.M.; Clement, D.E.; Graham, S.H. Clays and Clay Miner als 1983, 30, 129-34. 36. Pinnavaia, T.J. Science 1983, 220, 365-71. 37. Solomon, D.H.; Hawthorne, G.H. "Chemistry of Pigments and Fillers"; John Wiley & Sons: New York, 1983. 38. Solomon, D.H. Clays and Clay Minerals 1968, 16, 31-9. 39. Solomon, D.H.; Murray, H.H. Clays and Clay Minerals 1972, 20, 135-41. 40. Tennakoon, D.T.B.; Thomas, J.M.; Tricker, M.S. J. Chem. Soc. Dalton Trans. 1974, 20, 2211-5. 41. Rozenson, I.; Heller-Kallai, L. Clays and Clay Minerals 1978, 26, 88-92. 42. Rooney, J.J.; Pink, R.C. Trans. Farad. Soc. 1962, 58, 1632-41. 43. Solomon, D.H.; Loft, B.C.; Swift, J.D. Clay Minerals 1968, 7, 389-97. 44. Mortland, M.M.; Pinnavaia, T.J. Nature, Phys. Sci. 1971, 229, 75-7. 45. Fenn, D.B.; Mortland, M.M.; Pinnavaia, T.J. Clays and Clay Minerals 1973, 21, 315-22. 46. Rupert, J.P. J. Phys. Chem. 1973, 77, 784-90. 47. Pinnavaia, T.J.; Hall, P.L.; Cady, S.S.; Mortland, M.M. J. Phys. Chem. 1974, 78, 994-9. 48. Eastman, M.P.; Patterson, D.E.; Pannell, K.H. Clays and Clay Minerals 1984, 32, 327-33. 49. Mortland, M.M.; Halloran, L.J. Soil Sci. Soc. Amer. J. 1976, 40, 367-70. 50. Furukawa, T.; Brindley, G.W. Clays and Clay Minerals 1973, 21, 271-80. 51. Slade, P.G.; Raupach, M. Clays and Clay Minerals 1982, 30, 297-305. 52. Dodd, C.G.; Ray, S. Clays and Clay Minerals 1960, 8, 237-51. 53. Vansant, E.F.; Yariv, S. J.""Chem. Soc Faraday; Trans. I 1977, 73, 1815-24. 54. Thompson, T. D.; Moll, W.F. Clays and Clay Minerals 1973, 21, 337-60. 55. Soma, Y.; Soma, H.; Harada, I. J. Contaminant Hydrology 1986, 1, 95-106. 56. Frenkel, M.; Heller-Kallai, L. Clays and Clay Minerals 1983, 31, 92-6. 57. Sawhney, B.L. Clays and Clay Minerals 1985, 33, 123-7. 58. Sawhney, B.L.; Kozloski, R.P. J. Environ. Qual. 1984, 13, 349-52. 59. Taylor, W.I.; Battersby, A.R. "Coupling of Phenols"; Marcel Dekker: New York; 1967. 60. Isaacson, P.J.; Sawhney, B.L. Clay Minerals 1983, 18, 253-65. 61. Sawhney, B.L.; Kosloki, R.K.; Isaacson, P.J.; Gent, M.P.N. Clays and Clay Minerals 1984, 32, 108-14. 62. Wang, T.S.C.; Li, S.W.; Ferng, Y.L. Soil Science 1978, 126, 15-21.

486

63· 64. 65. 66. 67. 68. 69. 70. 71. 72. 73. 74. 75. 76. 77. 78. 79. 80. 81. 82. 83. 84. 85. 86. 87. 88. 89. 90.


Moreale, Α.; Cloos, P.; Badot, C. Clay Minerals 1985, 20, 29-37. Tricker, M.J.; Tennakoon D.T.B.; Thomas, J.M.; Heald, J. Clays and Clay Minerals 1975, 23, 77-82. Mortland, M.M."Raman, K.V. Clays and Clay Minerals 1968, 16, 393-8. Frenkel, M. Clays and Clay Minerals 1974, 22, 435-41. Solomon, D.H.; Swift, J.D.; Murphy, A.J. J. Macromol. Sci.Chem. 1971, A5, 587-601. Sohn, J.R.; Ozaki, A. J. Catalysis 1980, 61, 29-38. Davitz, J.C. J. Catalysis 1976, 43, 260-3. Mingelgrin, U.; Saltzman, S.; Yaron, B. Soil Sci. Soc. Am. J. 1977, 41, 519-23. Saltzman, S.; Mingelrin, U.; Yaron, B. J. Agric. Food Chem. 1976, 24, 739-43. Sanchez Camazano, M.S.; Sanchez Martin, M.J. Soil Science 1983, 136, 89-93. Russell, J.D.; Cruz, M.; White, J.L.; Bailey, G.W.; Payne, W.R.; Pope, J.D.; Teasley, J.I. Science 1968, 160, 1340-2. El-Amamy, M.M.; Mill, T. Clays and Clay Minerals 1984, 32, 67-73. Ballantine, J.A.; Purnell, J.H.; Thomas, J.M. Clay Minerals 1983, 18, 347-56. Fripiat, J.J.; Cruz, M.; Bohor, B.F; Thomas, J. Jr. Clays and Clay Miner. 1974, 22, 23-30. Fusi, P.; Ristori, G.G.; Cecconi, S.;Franci, M. Clays and Clay Minerals 1983, 31, 312-4. March, J. "Advanced Organic Chemistry, Reactions, Mechanisms, and Structure," 3rd. Ed.; John Wiley & Sons: New York; 1985. Mabey, W.; Mill, T. J.Phys. Chem. Ref. Data 1978, 7, 383-415. McAuliffe, C.; Coleman, N.T. Soil Sci. Soc. Proc. 1955, pp. 156-60. van Damme, H.; Crespin, M.; Obrecht, F.; Cruz, M.I.; Fripiat, J.J. J. Colloid Interface Sci. 1978, 66, 43-54. Atkins, M.P.; Smith,D.J.H.; Westlake, D.J. Clay Minerals 1983, 18, 423-9. Mackenzie, A.S. Clay Minerals 1984, 19, 271-86. Yaron, B. Soil Sci. Soc. Amer. Proc. 1975, 39, 639-43. Jenne, E.A. In "Trace Inorganics in Water"; Baker, R.A., Ed.; Adv. Chem. Ser. 73; Amer. Chem. Soc.; 1968; pp. 337-87. Shindo, H.; Huang, P.M. Nature (London) 1982, 298, 363-5. Suflita, J.M.; Loll, M.J.; Snipes, W.C.; Bollag, J.-M. Soil Science 1981, 131, 145-50. Flaig, W.; Beutelsbacher, H.; Rietz, E. In "Soil Components, Vol. 1, Organic Components"; Gieseking, J.E., Ed.; Springer: Berlin, 1975, pp. 1-211. Haider, K.; Martin, J.P.; Filip, Z. In "Soil Biochemistry," Vol. 4; Paul E.A.; McLaren, A.D., Eds.; Marcel Decker: New York, 1975, pp. 195-244. Voudrias, E.A. "Effects of Activated Carbon on Free and Com bined Chlorine with Phenols"; Ph.D. Thesis; University of Illi nois, Urbana, 1985.

RECEIVED

June 18, 1986

Geochemical Processes at Mineral Surfaces - ACS Publications

Recommend Documents