Selective Hydrogenation of Polyunsaturated Olefins - American

1 SelectiveHydrogenationof Polyunsaturated Olefins JOHN

C.

BAILAR,

JR.

Downloaded by CORNELL UNIV on July 29, 2016 | http://pubs.acs.org Publication Date: May 5, 1979 | doi: 10.1021/ba-1979-0173.ch001

University of Illinois, Urbana, IL 61801

The selective hydrogenation of soybean methyl ester, short chain dienes, and cyclooctadiene to the monoene stage under the catalytic influence of [Pt(PO ) (SnCl )Cl] is described. In this catalyst, the platinum can be replaced by palladium, the phosphorus by arsenic, antimony, sulfur, or selenium, the phenyl groups by other aromatic, aliphatic, or ester groups, the tin by lead or germanium, and the chlorine by bromine, iodine, or cyanogen. Terminal double bonds, even in monoenes, are hydrogenated. Isomerization to conjugation apparently precedes hydrogenation. Under mild conditions only isomerization is observed. The isomerized products are largely in the trans form. The catalyst, when made heterogeneous by attaching it to cross-linked polystyrene, still retains its ability to hydrogenate polyunsaturated molecules selectively. 3

2

3

T~*he t e r m , "selective h y d r o g é n a t i o n , " as i t is u s e d i n this d i s c u s s i o n , refers to t h e hydrogénation of some of t h e d o u b l e b o n d s i n a m o l e c u l e , l e a v i n g other,

similar bonds unattacked.

subject b e g a n w i t h the hydrogénation

O u r research

o n this

of s o y b e a n m e t h y l ester, w h i c h ,

i n its o r i g i n a l f o r m , is a m i x t u r e o f t h e g l y c e r i n e esters o f l i n o l e n i c , l i n o l e i c , oleic, stearic, a n d p a l m i t i c a c i d s .

F o r o u r studies, t h e g l y c e r o l

ester has b e e n c o n v e r t e d to t h e m e t h y l ester ( s h o w n i n T a b l e I ). M o s t o f t h e s o y b e a n o i l of c o m m e r c e is u s e d i n t h e m a n u f a c t u r e o f o l e o m a r g a r i n e , s a l a d oils, s a l a d dressings, a n d other foods. U n f o r t u n a t e l y , l i n o l e n i c ester has a p o o r flavor, so i t is d e s i r a b l e t o h y d r o g e n a t e o n e o f t h e d o u b l e b o n d s , l e a v i n g t h e others intact.

Ideally, the ethylenic b o n d

i n t h e 15-position w o u l d b e r e d u c e d , a n d a l l of t h e d o u b l e b o n d s r e m a i n i n g w o u l d r e t a i n t h e i r positions a n d t h e i r c i s configurations. 0-8412-0429-2/79/33-173-001$05.0O/0 © 1979 American Chemical Society King; Inorganic Compounds with Unusual Properties—II Advances in Chemistry; American Chemical Society: Washington, DC, 1979.

2

INORGANIC COMPOUNDS W I T H UNUSUAL PROPERTIES


Table I.

Major Constituents of

Soybean

II

Oil°

15 12 9 CCC=CCG=CCC=CCCCCCCCCOOR

linolenic

CCCCCC=CCC=CCCCCCCCCOOR

linoleic

50%

CCCCCCCCC=CCCCCCCCCOOR

oleic

27%

CCCCCCCCCCCCCCCCCCOOR

stearic

CCCCCCCCCCCCCCCCOOR

palmitic

9%

4 %

10%

• A l l double bonds are cis.

A great d e a l of w o r k has b e e n d o n e o n t h e selective h y d r o g e n a t i o n of p o l y o l e f i n i c m a t e r i a l s , i n c l u d i n g n a t u r a l oils as w e l l as h y d r o c a r b o n s , a n d a l a r g e n u m b e r of catalysts has b e e n u s e d (1-22). effective

only o n conjugated

systems,

S o m e of these are

some b r i n g a b o u t m i g r a t i o n of

o l e f i n i c b o n d s to c o n j u g a t i o n a n d t h e n r e d u c t i o n , a n d s t i l l others b r i n g a b o u t h y d r o g e n a t i o n of t e r m i n a l d o u b l e a n d t r i p l e b o n d s t h o u g h the s e l e c t i v i t y is n o t a l w a y s c o m p l e t e (23). Abley and McQuillan

(24)

selectively,

It was reported b y

t h a t i s o m e r i z a t i o n of oetene-1 takes

place

o n l y i n the p r e s e n c e of h y d r o g e n , b u t B a i l a r a n d I t a t a n i f o u n d t h a t soyb e a n ester isomerizes i n t h e a b s e n c e of h y d r o g e n

(25).

T h e t w o classes of p o l y o l e f i n i c c o m p o u n d s t h a t h a v e r e c e i v e d greatest a m o u n t of a t t e n t i o n i n r e g a r d to selective

hydrogenation

the are

n a t u r a l oils (e.g., s o y b e a n , cottonseed) a n d h y d r o c a r b o n s . I n b o t h cases, a v a r i e t y o f catalysts a n d solvents has b e e n u s e d . C a n d l i n a n d O l d h a m h a v e r e v i e w e d this subject a n d , i n the same a r t i c l e , h a v e d i s c u s s e d t h e i r o w n w o r k (26).

T h e y h y d r o g e n a t e d a n u m b e r of p o l y o l e f i n i c alkenes

a l k y n e s u s i n g the W i l k i n s o n

catalyst,

RhCl(P0 ) . 3

3

They found

and that

t e r m i n a l alkenes are h y d r o g e n a t e d m o r e s l o w l y t h a n u n s u b s t i t u t e d ones (as h a d b e e n f o u n d b y other i n v e s t i g a t o r s ) s l o w l y t h a n t e r m i n a l alkenes.

a n d c y c l i c alkenes

more

T h e y n o t e d t h a t t h e r a t e of h y d r o g e n a t i o n

is d e p e n d e n t o n the c o o r d i n a t i n g a b i l i t y of the substrate, a n d t h a t s u b strates c o n t a i n i n g e l e c t r o n w i t h d r a w i n g g r o u p s h y d r o g e n a t e r a p i d l y .

For

t h e h y d r o g e n a t i o n of h y d r o c a r b o n s , T a k e g a m i et a l . u s e d F e C l

and

King; Inorganic Compounds with Unusual Properties—II Advances in Chemistry; American Chemical Society: Washington, DC, 1979.

3

1.

BAILAR

Selective

L1AIH4 i n T H F (27). and

Al(i-bu)

K Co(CN) 3

5

Hydrogenation

3

Olefins

T i k h o m i r o v et a l . u s e d a m i x t u r e of

i n d e c a l i n (28),

3

of

(4,5,6,7).

metallic compounds 5

3

used

T a j i m a a n d K u n i o k a u s e d a v a r i e t y of o r g a n o (e.g., C p V C l , C p Z r C l , 2

2

2

CpCo(CO) , n-C H Li,

2

2

C H M g B r , B u A l ) w i t h m o d e r a t e success (29). 6

Cr(acac)

a n d K w i a t e k a n d his colleagues

4

9

F o r the selective r e d u c -

3

t i o n of cottonseed o i l , K a l i e v a n d B i z h a n o v u s e d a m i x t u r e of n i c k e l a n d m o l y b d e n u m (9:1)

w i t h o u t a solvent ( 5 0 ) ,

but Zueva and Potselueva

p r e f e r r e d a 1:1 m i x t u r e of p a l l a d i u m a n d n i c k e l i n absolute e t h a n o l

(31).

A catalyst c o n s i s t i n g of A l ( 4 8 % ), N i ( 4 0 % ), C u ( 1 0 % ), a n d C r ( 2 % ) w a s f o u n d to b e m u c h s u p e r i o r to the same m i x t u r e w i t h the c h r o m i u m Downloaded by CORNELL UNIV on July 29, 2016 | http://pubs.acs.org Publication Date: May 5, 1979 | doi: 10.1021/ba-1979-0173.ch001

left out, i n r e l a t i o n to the v e l o c i t y of h y d r o g e n a t i o n , t o t h e f o r m a t i o n of trans acids, a n d to the degree of i s o m e r i z a t i o n (32).

I n r e c e n t years, at

least, the selective h y d r o g e n a t i o n of s o y b e a n ester has r e c e i v e d f a r m o r e attention t h a n that of other vegetable oils. F r a n k e l a n d his c o - w o r k e r s h a v e h a d excellent success w i t h m e t a l c a r b o n y l s (33-38).

F o r the m o s t

part, they u s e d i r o n a n d c h r o m i u m c a r b o n y l s , w h i c h gave g o o d selectivity. T h e y f o u n d that cobalt c a r b o n y l was m u c h i n f e r i o r . E m k e n , F r a n k e l , a n d B u t t e r f l e l d also u s e d the acetylacetonates of N i ( I I I ) , C o ( I I I ) , and

Fe(III)

Cu(II),

[ N i ( I I I ) a c a c ] w a s the most a c t i v e a n d the

(45).

most

3

selective of this g r o u p . [ C u a c a c ]

s h o w e d l i t t l e selectivity.

2

They found

that no h y d r o g e n a t i o n took p l a c e i n the absence of solvents, a n d that m e t h a n o l w a s a better solvent t h a n either acetic a c i d or d i m e t h y l f o r m amide.

The

chief

products

were

monoenes,

as l o n g as

some

triene

r e m a i n e d . T h e y r e p o r t e d that the nature of the solvent h a d l i t t l e effect o n the rate of catalysis, except that w h e n the solvent c o n t a i n e d p y r i d i n e t h e r e a c t i o n w a s extremely slow. B a i l a r a n d T a y i m (46),

however, found

that c h l o r i n a t e d h y d r o c a r b o n s gave a m u c h faster r e a c t i o n t h a n d i d a b e n z e n e - m e t h a n o l m i x t u r e a n d that the presence of p y r i d i n e or t h i o p h e n e c o m p l e t e l y b l o c k e d the r e a c t i o n . T h e v e r y h i g h selectivity of H P t C l - S n C l 2

4

2

and H P t C l - S n C l 2

tures w a s first o b s e r v e d b y B a i l a r a n d I t a t a n i (47).

6

mix-

2

T h i s was b a s e d o n

the o b s e r v a t i o n of C r a m e r , Jenner, L i n d s e y , a n d S t o l b e r g (48)

t h a t this

catalyst w a s e x t r e m e l y effective f o r the h y d r o g e n a t i o n of ethylene.

Lind-

sey's g r o u p has p u b l i s h e d extensively o n the P t - S n c h l o r i d e c o m p l e x , b u t not i n terms of its c a t a l y t i c selectivity (49,50,51). c o - w o r k e r s (20),

B o n d a n d H e l l i e r (53),

v a n B e k k u m a n d his

a n d van't H o f a n d L i n s e n h a v e

u s e d this catalyst f o r the h y d r o g e n a t i o n of polyolefins b u t not f o r veget a b l e o i l esters (54).

S e v e r a l investigators h a v e r e p o r t e d that the m o l e

ratio of p l a t i n u m to t i n is i m p o r t a n t , b u t t h e i r estimates of the o p t i m u m r a t i o v a r y f r o m 1:5 to

1:10.

B a i l a r a n d I t a t a n i later a d o p t e d

[Pt(P0 ) Cl ] 3

2

2

+

SnCl

2

as

the

catalyst f o r the h y d r o g e n a t i o n o f s o y b e a n ester. T h i s c o m p l e x seems t o h a v e the highest s e l e c t i v i t y of a n y that have b e e n s t u d i e d . F r a n k e l a n d


4

INORGANIC COMPOUNDS W I T H UNUSUAL PROPERTIES

II

0 his associates

have recently

(55,56,57)

f o u n d that

cyclopentadiene


c h r o m i u m t r i c a r b o n y l is selective a n d gives cis p r o d u c t s . It is a s u p e r i o r catalyst f o r this p u r p o s e . We

were

a s k e d several years

ago

by

the

Northern Utilization

R e s e a r c h a n d D e v e l o p m e n t D i v i s i o n of the U . S . D e p a r t m e n t of A g r i c u l t u r e to s t u d y this selective h y d r o g e n a t i o n . W h i l e o u r efforts h a v e n o t y e t l e d to c o m p l e t e success, t h e y h a v e l e d to some i n t e r e s t i n g a n d u s e f u l results.

I n a d d i t i o n to s o y b e a n m e t h y l ester, w e h a v e e x a m i n e d some

short c h a i n diolefins a n d some c y c l i c c o m p o u n d s s u c h as c y c l o o c t a d i e n e . T h e catalyst that w e first u s e d w a s suggested b y the w o r k of C r a m e r , L i n d s e y , P r e w i t t , a n d S t o l b e r g . It is a m i x t u r e of c h l o r o p l a t i n i c a c i d ( I V ) and tin (II)

c h l o r i d e . W e f o u n d that i t is also a selective catalyst f o r t h e

h y d r o g e n a t i o n of s o y b e a n ester—selective i n t h e sense t h a t i t leaves one double bond unhydrogenated. We

soon m o d i f i e d this catalyst

to

g a i n greater

selectivity, a n d

t h r o u g h o u t most of o u r w o r k w e h a v e u s e d [ P t ( P 0 ) C l ] + 3

2

S n C l . This,

2

2

h o w e v e r , is o n l y o n e of a l a r g e f a m i l y of materials that h a v e the

same

c a t a l y t i c p r o p e r t i e s , some to a greater degree a n d some to a lesser degree. I n s t e a d of p l a t i n u m , p a l l a d i u m c a n b e u s e d . It gives a m u c h m o r e a c t i v e catalyst t h a n p l a t i n u m .

I n fact, i n m a n y cases t h e p a l l a d i u m catalyst is

effective w i t h o u t a n y a d d i t i o n of t i n c h l o r i d e . N i c k e l c a n also b e u s e d , b u t the p r o p e r t i e s of the r e s u l t i n g catalyst are s o m e w h a t d i f f e r e n t t h a n those of the p l a t i n u m catalyst. arsenic,

T h e phosphorus can be replaced

antimony, sulfur, or selenium.

A r s e n i c gives a m o r e

active

Table II. Hydrogenation of Propylene at 4 4 ° C and 500 psi of Hydrogen in Chloroform with [ P t C l L ] + S n C l • 2 H 0 2

24.5 24.4

3

P(p-CH 0) 8

P(CH )0 P(CH ) 0 3

3

8

3

76.9 91.8

2

2

P(CH ) P(CH CH CH CH ) 2

3

2

2

% Propane after 3 hr

L

P0

2

2

3

3

6.0 7.0


by

2

1.

BAILAR

Selective

Hydrogenation

5

of Olefins

catalyst t h a n p h o s p h o r u s ; t h e others are less active.

T h e p h e n y l groups

of t h e t r i p h e n y l p h o s p h i n e c a n b e r e p l a c e d b y other a r o m a t i c g r o u p s , phenoxy groups, or, i n part, b y aliphatic groups. T h e presence of one o r t w o a l i p h a t i c g r o u p s increases t h e c a t a l y t i c a c t i v i t y , b u t t r i a l k y l p h o s p h i n e s g i v e p o o r catalysts. reaction.

Table

T h e p h e n y l g r o u p e v i d e n t l y takes p a r t i n t h e

I I illustrates t h e r e l a t i v e activities o f some

c o n t a i n i n g different p h o s p h i n e s . T h e h a l i d e s i n t h e S n C l

3

catalysts

group c a n be

chloride, bromide, iodide, or cyanide. If [ P t ( P R ) I ] or [ P t ( P 0 ) ( C N ) ] 3

2

2

3

2

2

is u s e d i t is n o t necessary t o a d d a t i n h a l i d e , f o r i o d i d e a n d c y a n i d e , like the S n C l

g r o u p , are o- donors as w e l l as ?r acceptors.

3

I o d i d e is also


a 7T d o n o r . 14 H

12Jl

10-

3

cis: 23.2%

I—| trans:76.8%'

6

4

5

6

7 8 9 10 11 12 13 14 15 Bond Position Journal of Organic Chemistry

Figure 1.

Distribution of the ethylenic bonds after selective hydrogenation (14)

T h e p r o p e r t i e s of this g r o u p of catalysts follows: ( 1 ) U n d e r suitable conditions, they leave hydrogenated.

c a n b e s u m m a r i z e d as one double bond u n -

( 2 ) T h e y c a t a l y z e t h e m i g r a t i o n of t h e d o u b l e b o n d s a l o n g t h e c a r b o n c h a i n . F r a n k e l a n d E m k e n (14) o b s e r v e d t h e d i s t r i b u t i o n of t h e one u n h y d r o g e n a t e d d o u b l e b o n d i n s o y b e a n ester t o b e as s h o w n i n F i g u r e 1 . U n d e r suitable c o n d i t i o n s , this i s o m e r i z a t i o n c a n b e effected without hydrogenation.


6

INORGANIC COMPOUNDS W I T H UNUSUAL

PROPERTIES

II

( 3 ) T h e d o u b l e b o n d i n the esters that are f o r m e d are m o s t l y of t h e trans c o n f i g u r a t i o n (see F i g u r e 1 ) . ( 4 ) W i t h s h o r t - c h a i n diolefins, at least, t e r m i n a l d o u b l e b o n d s r e d u c e d e v e n if there are no other d o u b l e b o n d s present.

are

( 5 ) S h o r t - c h a i n c o n j u g a t e d diolefins, s u c h as b u t a d i e n e a n d isop r e n e , not o n l y are not r e d u c e d , b u t t h e y f o r m stable c o m p l e x e s w i t h the catalyst a n d thus destroy its c a t a l y t i c p r o p e r t y . T h e n a t u r e of the solvent is v e r y i m p o r t a n t .

I n o u r early w o r k w e

u s e d a 3 : 2 m i x t u r e of b e n z e n e a n d m e t h a n o l , w h i c h dissolves b o t h t h e substrate a n d the catalyst.

H o w e v e r , t h e r e a l i z a t i o n t h a t m e t h a n o l is a


m o d e r a t e l y g o o d c o m p l e x i n g agent ( i t p r o b a b l y f o r m s a stronger b o n d to P t ( I I ) t h a n does

C=C

) c a u s e d us to search f o r a n o n c o o r d i n a t i n g

catalyst. T h i s search w a s not e n t i r e l y successful, b u t i t l e d to e x p e r i m e n t s w i t h n o n c o o r d i n a t i n g solvents. methylene chloride.

T h e best solvent t h a t w a s f o u n d w a s

I n a l l p r o b a b i l i t y , t h e olefin a n d the h e a v y m e t a l

f o r m a c o m p l e x t h a t is sufficiently " o r g a n i c " to d i s s o l v e i n this solvent. D i c h l o r o e t h a n e is almost e q u a l l y active, a n d e v e n c h l o r o f o r m c a n used.

be

A c e t o n e a n d acetic a c i d are also s u i t a b l e a n d a l l o w the r e a c t i o n

to p r o c e e d m o r e r a p i d l y t h a n does t h e b e n z e n e - m e t h a n o l m i x t u r e .

Pyri-

d i n e a n d t h i o p h e n e are catalyst poisons; e v e n a t r a c e of either of t h e m c o m p l e t e l y destroys the c a t a l y t i c a c t i v i t y . W i t h s o y b e a n ester, at least, m e t h a n o l c a n serve as the r e d u c i n g agent, the r e d u c t i o n t a k i n g p l a c e at a b o u t the same rate as w h e n h y d r o g e n is u s e d . T a b l e I I I shows the h y d r o g e n a t i o n of 1,5-cyclooctadiene different solvents or solvent m i x t u r e s .

I n a l l cases, the

i n several

1,5-hydrocarbon

Table III. Hydrogenation of 1,5-Cyclooctadiene in Various Solvents with and without Added Sn(II) Chloride 0

Composition Solvent CH2CI2 CH2CI2 + CH3OH + CH3OH (4:1) CH3COOH CH3COOH CH C1 CH C1 2

2

2

2

C H + CH3OH C H + CH3OH (3:2) 6

6

6

6

SnCl

Added

2

of

Product

1,3-Cyclooctadiene

Cyclooctene

Cyclooctane

SnCl

2

• 2H 0

40 82

58 18

2 0

SnCl

2

• 2H 0

4 93

93 7

3 0

SnCl

2

0 90

81 10

19 0

SnCl

2

0 12

81 88

19 0

2

2

—

Reaction time, 5 hr; [Pd(P0 )2Cl ]: 90°C. 3

2


1.

BAILAR

Selective

Table I V .

Hydrogenation

P t

5d

78

ui> 4

n t

Rn

O

o

o

O

o

o

o o o o o o

76

[PtX ]

Olefins

7

Electronic Structure of Pt(II) and Its

e" Pt°

of

84 86

o o o o o o

o o o o 0 o

Complexes

6s

o

o

o

X X o o

X X o o

6d

o

o o o o o o

X X o o

X X o o

o o


w a s i s o m e r i z e d to the 1,3-configuration b e f o r e a n y samples w e r e r e m o v e d f o r analysis, a n d t h e 1,3-isomer w a s p a r t i a l l y o r e n t i r e l y r e d u c e d to c y c l o octene or c y c l o o c t a n e .

It s h o u l d b e n o t i c e d also that i n a l l cases, i n t h e

presence of t i n c h l o r i d e , there has b e e n n o r e d u c t i o n to c y c l o o c t a n e T h e m e c h a n i s m o f t h e c a t a l y t i c r e a c t i o n is not f u l l y k n o w n .

(58). Four-

c o v a l e n t complexes o f P t ( I I ) , P d ( I I ) , a n d N i ( I I ) l a c k t w o electrons o f the next rare gas structure, so t h e y h a v e a v a c a n t space i n t h e c o o r d i n a t i o n sphere.

T h i s is s h o w n f o r p l a t i n u m i n T a b l e I V .

T h e r e is

some

e v i d e n c e that t h e e a r l y p a r t of the r e a c t i o n p r o c e e d s t h r o u g h the steps: CI

0 P. 3

P f CI

0 P. 3

SnCl

SnCl,

3

H, CI

P03

SnCl,

0 P.

3

P0

Pt H

3

P0s

a n d t h a t the h y d r i d e is the a c t u a l catalyst. T h i s c o m p o u n d has not b e e n i s o l a t e d , b u t a d d i t i o n of t r i e t h y l a m i n e a l l o w e d the i s o l a t i o n of t r i e t h y l amine hydrochloride (59). If w e a b b r e v i a t e the f o r m u l a f o r [ ( P t or P d ) ( P 0 ) ( S n C l ) H ] 3

2

3

to

M H , the r e a c t i o n sequence m a y b e s o m e t h i n g l i k e t h a t s h o w n b e l o w . ( N o experiments h a v e b e e n d o n e w i t h l a b e l e d h y d r o g e n , b u t s o m e of the h y d r o g e n atoms i n this figure h a v e b e e n m a r k e d f o r i d e n t i f i c a t i o n . ) R e a c t i o n 1 shows the f o r m a t i o n of a TT b o n d b e t w e e n the catalyst a n d o n e of t h e e t h y l e n i c b o n d s , a n d R e a c t i o n 2 shows t h e c o n v e r s i o n of this b o n d i n t o t w o o- b o n d s .

B o t h of these reactions

are r e v e r s i b l e .

However,

R e a c t i o n 3 c a n t a k e p l a c e as r e a d i l y as R e a c t i o n 2; this accounts f o r t h e m i g r a t i o n of the d o u b l e b o n d a l o n g the h y d r o c a r b o n c h a i n . R e a c t i o n 4 illustrates t h e f o r m a t i o n of a n a d d i t i o n a l TT b o n d a n d the f o r m a t i o n of a c y c l e . U p o n h y d r o g e n a t i o n , t h e c a r b o n - m e t a l a b o n d is b r o k e n , w i t h o n e h y d r o g e n a t o m g o i n g to the c a r b o n a t o m a n d t h e o t h e r to the catalyst. H y d r o g e n a t i o n takes p l a c e o n l y w h e n this c y c l e is present.

If the p o l y -

olefin contains a n o t h e r d o u b l e b o n d , R e a c t i o n s 1, 2, a n d 3 c a n p r o c e e d u n t i l t h e t w o r e m a i n i n g d o u b l e b o n d s are close e n o u g h together to a l l o w


8


INORGANIC

COMPOUNDS

WITH

UNUSUAL

PROPERTIES—II

Ho

H c / H HCH* \

H — c H°

A

M H 'C : H

A

C H

the formation of a new cycle, when Reactions 4 and 5 take place. Since the formation of the cycle must involve two double bonds, hydrogenation stops when only one remains. T h e isolation of an allylic intermediate in the hydrogenation of 1,5-cyclooctadiene (Figure 2) is i n line with this mechanism (58).



1.

BAILAR

Selective

Hydrogenation

of

9

Olefins

Figure 2. PMR spectrum of [PdCl(C H )(PO )] CDCl . [ ] represents the number of protons. H : 3.85 ppm, ] = ca. 6.9 Hz, ] = ca. 6.8 Hz; 8 = 5.41 ppm, J = ca. 6.9 Hz; H : 8 = 5.39 ] = ca. 9.6 Hz, J = ca. 6.9 Hz. 8

13

s

3

(1)

12

ljS

2

3

3

(s)

p

in 8 == H ): ppm, (2

3A

U n d e r m i l d conditions, isomerization can take place without hydrog e n a t i o n . T h i s , of course, is most e v i d e n t w h e n h y d r o g e n gas is n o t u s e d ; u n d e r that c o n d i t i o n , the r e a c t i o n has b e e n s t u d i e d i n some d e t a i l ( F i g u r e s 3 and 4).

It is p r o b a b l e that i s o m e r i z a t i o n to c o n j u g a t i o n

precedes

h y d r o g e n a t i o n i n a l l cases. W e t h o u g h t at one t i m e t h a t this is n o t the case, f o r 2 , 3 , 3 - t r i m e t h y l - p e n t a d i e n e

w h i c h cannot f o r m conju-

(1-22,25),

gate b o n d s , is r e a d i l y h y d r o g e n a t e d ( T a b l e V ) . W e h a v e l e a r n e d since, h o w e v e r , that t e r m i n a l d o u b l e b o n d s h y d r o g e n a t e e v e n w h e n n o other e t h y l e n i c g r o u p s are present.

Table V .

T h i s is s h o w n i n T a b l e V I . T h i s shows t h e

Hydrogenation of 2,3,3-Trimethyl-l,4-pentene

CH3 CH2=C

CH3 C—CH =CH2 :

CH

CH3 CH2=C

3

CH3

CH3 C—CHo—CH3

CH

8

CH —CH 3

CH3 C—CH=CH i CH

3


2

INORGANIC

10

Table V I .

COMPOUNDS WITH UNUSUAL

II

Catalytic Hydrogenation of Monoenes with P t C l ^ P O s ) ^ and S n C l • 2 H 0 i n Benzene—Methanol (3 hr) 2

2

1-Isorrier


PROPERTIES

Ethylene Propylene 1-Butene as-2-Butene £rans-2-Butene 1-Pentene 2-Pentene (cis 47.9; t r a n s 52.1) 1-Hexene 2-Hexene 3-Hexene°

2- Isomer cis

trans

0 66 12.0 0 0 11.6 3.0

30.3 71.1 9.8 30.2 27.7

46.4 27.3 89.6 47.2 67.5

12.5

28.5

41.6

3-Isomer

Saturated Hydrocarbon 100 34 11.3 1.6 0.6 11.6 1.8

5.6

12.0

a

° N o observable hydrogenation. p r o d u c t s of h y d r o g e n a t i o n of some short c h a i n h y d r o c a r b o n s a f t e r 3 h r of h y d r o g e n a t i o n .

I n t h e case o f ethylene, h y d r o g e n a t i o n w a s

complete

i n less t h a n 1 h r . A s t h e c h a i n o n o n e side o f t h e d o u b l e b o n d is l e n g t h e n e d b y o n e o r t w o m e t h y l groups, t h e rate o f h y d r o g e n a t i o n is decreased.

F u r t h e r l e n g t h e n i n g seems t o h a v e l i t t l e effect. I f t h e c h a i n

is l e n g t h e n e d o n b o t h sides o f t h e e t h y l e n i c b o n d , h o w e v e r , v e r y little h y d r o g e n a t i o n takes p l a c e , a n d that l i t t l e m a y b e p r e c e d e d b y m i g r a t i o n of t h e d o u b l e b o n d i n t o a t e r m i n a l p o s i t i o n . F i g u r e s 3 a n d 4 c o m p a r e t h e c o n d i t i o n s u n d e r w h i c h i s o m e r i z a t i o n a n d h y d r o g e n a t i o n o f 1,5-cyclo-

Journal of the American Chemical Society

Figure 3. Catalytic isomerization of 1,5-cyclooctadiene in C H -CH OH solution under 1 atm N at 60°C (15) 6

6

3

2


1.

BAILAR

Selective

Hydrogenation

of Olefins

11

100

,5-C0D Cyclooctene


1,3-COD

100

J 200

150

Time

I 250

I 300

I 350

L 400

in Minutes Journal of the American Chemical Society

Figure

4.

Catalytic

hydrogenation of 1,5-cyclooctadiene ride under 500 psi H at 105°C (16)

in methylene

chlo-

2

o c t a d i e n e take p l a c e . It is e v i d e n t f r o m F i g u r e 4 that t h e i s o m e r i z a t i o n is r e v e r s i b l e a n d reaches a n e q u i l i b r i u m after a b o u t 200 m i n . Short c h a i n dienes often s h o w i n t e r e s t i n g a n d i n s t r u c t i v e results.

T a b l e V I I shows

the results that w e r e o b t a i n e d w i t h isoprene w i t h different catalysts a n d solvents

(13).

N e a r the e n d o f o u r w o r k w i t h s o y b e a n m e t h y l ester, w e fixed the catalyst o n p o l y s t y r e n e c r o s s - l i n k e d w i t h d i v i n y l b e n z e n e , thus m a k i n g i t a heterogeneous catalyst ( T a b l e V I I I ) .

W h e t h e r the h e a v y m e t a l f u r t h e r

cross-links the p o l y m e r or is a t t a c h e d to p h o s p h o r u s atoms o n a single p o l y s t y r e n e c h a i n is not k n o w n . I n a n y event, the heterogeneous has the same sort of selectivity as the h o m o g e n e o u s one.

catalyst

I n no case d i d

w e s u c c e e d i n g e t t i n g a l l of the p h o s p h o r u s atoms i n t h e p o l y m e r a t t a c h e d to t h e h e a v y m e t a l of the catalyst.

The

first

entry i n T a b l e I X ,

for

e x a m p l e , indicates that for e a c h u n i t of the p o l y m e r , 0.505 m o l e c u l e s of PtCl

2

were attached.

I n the cases i n w h i c h p a l l a d i u m c h l o r i d e w a s u s e d ,

no t i n c h l o r i d e w a s a d d e d — t h e p a l l a d i u m c h l o r i d e is sufficiently a c t i v e w i t h o u t it. It is e v i d e n t that i t is p o s s i b l e to destroy t h e triene w i t h o u t g r e a t l y i n c r e a s i n g the a m o u n t of s a t u r a t i o n i n the o i l . W e are s t i l l w o r k i n g o n this catalyst system, a n d h o p e to h a v e m o r e results to r e p o r t b e f o r e long.


12

INORGANIC

COMPOUNDS WITH UNUSUAL

Table V I I .

3

) ) ) )

2

3

Solvent

3 3

Cl + SnCl Cl + SnCl (CN) I 2

2

2

2 2

II

Hydrogenation of Isoprene w i t h

Catalyst

Pt(P0 Pd(P0 Pd(P0 Ni(P0

PROPERTIES

CH COOH + CH COCH CH COOH C H + C H O H (3:2) CH OH 3

2

3

3

(4:1)

3

2

6

2

6

3

s

2

" 5 5 a t m H ; 5 h r ; 100°C.


2

Table VIII.

Polymeric Catalysts*

\ CH

C H

2

CH,C1

* The structure on the left is actually a copolymer of chloromethylstyrene and divinyl benzene.

Table I X .

Hydrogenation of Soybean Metal/'Olefin Ratio X 10

Solvent

Catalyst

s

O r i g i n a l substrate [ P o l . ( P t C l a ) 0.505] 150° C 600 p s i H

2

[Pol. (PdCl ) .85l] 25 ° C 600 p s i H

2

2

0

2

CH C1

2

1.02

2

2

2

[Pol. ( P d C l ) 70°C

0.62

3

0

[ P o l . ( P t C l ) 0.505] 150°C + SnCl

2

2

j CH OH

[Pol. (PdCl ) .85l] 25°C 1 atm H 2

CH C1

2

CH C1 2

0.48

2

0.507]


1.

BAILAR

Selective

Hydrogenation

13

of Olefins

Different Catalysts and Different Solvents' Product

C

C

C=C-G===C


1 30 12 100

c

63 20 64 —

8 1 11 —

(hr)

Saturate

C-C-C=C

0 49 12 —

C-C-C-C

28 — 1 —

Catalyst Composition

m e

5

C

C=C-C-C

C - C = C - C

Ester on the Heterogeneous Yi

(%)

Monoene

of

Diene

Product Con]. Diene

Triene

14.2

22.3

56.2

7.0

6

14.5

37.8

28.3

20.1

—

4

15.1

60.4

24.3

—

—

8

14.3

62.4

23.4

—

—

6

13.8

26.6

39.2

18.4

2.0

3

14.8

35.2

45.9

—

4.3


14

INORGANIC

COMPOUNDS

WITH

UNUSUAL PROPERTIES

II

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. 32. 33. 34. 35. 36. 37. 38. 39.

Slaugh, L. H., Tetrahedron (1966) 22, 1741. Slaugh, L. H., J. Org. Chem. (1967) 32, 108. Tajima, Y., Kunioka, E., J. Org. Chem. (1968) 33, 1689. Kwiatek, J., Catal. Rev. (1967) 1, 37. Kwiatek, J., J. Organomet. Chem. (1965) 3, 421. Kwiatek, J., Seyler, J. K., ADV. CHEM. SER. (1968) 70, 207. Kwiatek, J., Mador, I. L., Seyler, J. K., ADV. CHEM. SER. (1963) 37, 201. Burnett, M. G., Connolly, P. J., Kemball, C., J. Chem. Soc. A (1968) 991. Hallman, P. J., Evans, D., Osborn, J. A., Wilkinson, G., Chem. Commun. (1967) 305. Osborn, J. A., Jardine, F. H., Young, J. F., Wilkinson, G., J. Chem. Soc. A (1966) 1711. Jardine, F. H., Osborn, J. A., Wilkinson, G.,J.Chem. Soc. A (1967) 1574. Bailar, J. C., Jr., Itatani, H.,J.Am. Chem. Soc. (1967) 89, 1592. Itatani, H., Bailar, J.C.,Jr.,J.Am. Chem. Soc. (1967) 89, 1600. Frankel, E. N., Emken, E. A., Itatani, H., Bailar, J.C.,Jr., J. Org. Chem. (1967) 32, 1447. Tayim, H. A., Bailar, J.C.,Jr.,J.Am. Chem. Soc. (1967) 89, 3420. Ibid (1967)89,4330. Bailar, J. C., Jr., Itatani, H., Tayim, H., J. Jpn. Chem. (1968) 22, 41. Adams, R. W., Batley, G. E., Bailar, J. C., Jr.,J.Am. Chem. Soc. (1968) 90, 6051. Adams, R. W., Batley, G. E., Bailar, J. C., Jr., Inorg.Nucl.Chem. Lett. (1968) 4, 455. Bailar, J.C.,Jr., Platinum Met. Rev. (1971)15,2. Frankel, E. N., Itatani, H., Bailar, J. C., Jr.,J.Am. Oil Chem. Soc. (1972) 49, 132. Itatani, H., Bailar, J. C., Jr., IEC Prod. Res. Dev. (1972) 11, 146. Bond, G. C., Hellier,M.,J.Catal. (1967) 7, 217. Abley, P., McQuillin, F. J., Discuss. Faraday Soc. (1968) 46, 31. Bailar, J. C., Jr., Itatani, H., J. Am. Chem. Soc. (1967) 89, 1592. Candlin, J. P., Oldham, A. R., Discuss. Faraday Soc. (1968) 46, 60. Takegami, Y., Ueno, T., Fujii, T., Bull. Chem. Soc. Jpn. (1965) 38, 1279. Tikhomirov, B. I., Klopotova, I. A., Yakabchik, A. I., Vestn. Leningr. Univ., 22(22) , Fiz. Khim. (1967) 4, 147; Chem. Abstr. (1968) 68, 59020. Tajimia, Y., Kunioka, E., J. Org. Chem. (1968) 33, 1689. Kaliev, S. P., Bizhanov, F. B., Khim. Khim. Technol. (Alma-Ata) (1971) 2, 65; Chem. Abstr. (1974) 80, 13779n. Zueva, L. I., Potselueva, L. B., Tr. Inst. Org. Katal. Elektrokhim., Akad. Nauk Kaz. SSR (1973) 5, 82; Chem. Abstr. (1974) 80, 131770a. Nazarova, I. P., Kantsepol'skaya, F. M., Glushenkova, A. I., Markham, A. L., Maslo-Zhir. Promst. (1974) 2, 16; Chem. Abstr. (1974) 80, 131756a. Frankel, E. N., Jones, E. P., Glass, C. A., J. Am. Oil Chem. Soc. (1964) 41, 392. Frankel, E. N., Peters, H. M., Jones, E. P., Dutton, H. J.,J.Am. Oil Chem. Soc. (1964) 41, 186. Frankel, E. N., Jones, E. P., Davison, V. L., Emken, E., Dutton, H. J., J. Am. Oil Chem. Soc. (1965) 42, 130. Frankel, E . N., Emken, E . A., Davison, V. L., J. Am. Oil Chem. Soc. (1966) 43, 307. Frankel, E. N., Little, F. L., J. Am. Oil Chem. Soc. (1969) 46, 256. Frankel, E. N.,J.Am. Oil Chem. Soc. (1970) 47, 33. Ibid (1970) 47, 11.


1.

BAILAR

Selective

Hydrogenation

of

Olefins

15

40. Frankel, E. N., Metlin, S., Rohwedder, W. K., Wender, I.,J.Am. Oil Chem. Soc. (1969) 46, 133. 41. Frankel, E . N., Emken, E. A., Peters, H. M., Davison, V. L., Butterfield, R. D.,J.Org. Chem. (1964) 29, 3292. 42. Frankel, E . N., Emken, E. A., Davison, V. L., J. Org. Chem. (1965) 30, 2739. 43. Frankel, E. N., Selke, E., Glass, C. A., J. Org. Chem. (1969) 34, 3936. 44. Frankel, E . N., Mounts, T. L., Butterfield, R. O., Dutton, H . J., ADV.


C H E M . SER. (1968) 70, 177.

45. Emken, E. A., Frankel, E . N., Butterfield, R. O., J. Am. Oil Chem. Soc. (1966) 43, 14. 46. Tayim, H. A., Bailar, J.C.,Jr.,J.Am. Chem. Soc. (1967) 89, 4330. 47. Bailar, J.C.,Jr., Itatani, H., Proc. Symp. Coord. Chem., Hungary, 1964, 67. 48. Cramer, R. D., Jenner, E. L., Lindsey, R. V., Jr., Stolberg, U. G.,J.Am. Chem. Soc. (1963) 85, 1691. 49. Cramer, R. D., Lindsey, R. V., Jr., Prewitt, C. T., Stolberg, U. G.,J.Am. Chem. Soc. (1965) 87, 658. 50. Lindsey, R. V., Jr., Parshall, G. W., Stolberg, U. G., J. Am. Chem. Soc. (1965) 87, 658. 51. Parshall, G. W., J. Am. Chem. Soc. (1966) 88, 3534. 52. van Bekkum, H., van Gogh, J., van Minnen-Pathius, G., J. Catal. (1967) 7, 292. 53. Bond, G.C., Hellier, M., Chem. Ind. (London) (1965) 35. 54. van't Hof, L. P., Linsen, B. G., J. Catal. (1967) 7, 295. 55. Frankel, E. N., Butterfield, R. O.,J.Org. Chem. (1969) 34, 3930. 56. Frankel, E. N., Selke, E., Grass, C. A.,J.Org. Chem. (1969) 34, 3936. 57. Frankel, E. N.,J.Org. Chem. (1972) 38, 1549. 58. Fujii, Y., Bailar, J. C., Jr.,J.Catal.,in press. 59. Vassilian, A., experiment in the author's laboratory. RECEIVED February 22, 1978.


Selective Hydrogenation of Polyunsaturated Olefins - American

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