1 SelectiveHydrogenationof Polyunsaturated Olefins JOHN
C.
BAILAR,
JR.
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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
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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
King; Inorganic Compounds with Unusual Properties—II Advances in Chemistry; American Chemical Society: Washington, DC, 1979.
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
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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
King; Inorganic Compounds with Unusual Properties—II Advances in Chemistry; American Chemical Society: Washington, DC, 1979.
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
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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.
King; Inorganic Compounds with Unusual Properties—II Advances in Chemistry; American Chemical Society: Washington, DC, 1979.
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
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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
King; Inorganic Compounds with Unusual Properties—II Advances in Chemistry; American Chemical Society: Washington, DC, 1979.
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
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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
King; Inorganic Compounds with Unusual Properties—II Advances in Chemistry; American Chemical Society: Washington, DC, 1979.
8
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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).
King; Inorganic Compounds with Unusual Properties—II Advances in Chemistry; American Chemical Society: Washington, DC, 1979.
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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
King; Inorganic Compounds with Unusual Properties—II Advances in Chemistry; American Chemical Society: Washington, DC, 1979.
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
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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
King; Inorganic Compounds with Unusual Properties—II Advances in Chemistry; American Chemical Society: Washington, DC, 1979.
1.
BAILAR
Selective
Hydrogenation
of Olefins
11
100
,5-C0D Cyclooctene
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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.
King; Inorganic Compounds with Unusual Properties—II Advances in Chemistry; American Chemical Society: Washington, DC, 1979.
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.
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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]
King; Inorganic Compounds with Unusual Properties—II Advances in Chemistry; American Chemical Society: Washington, DC, 1979.
1.
BAILAR
Selective
Hydrogenation
13
of Olefins
Different Catalysts and Different Solvents' Product
C
C
C=C-G===C
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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
King; Inorganic Compounds with Unusual Properties—II Advances in Chemistry; American Chemical Society: Washington, DC, 1979.
14
INORGANIC
COMPOUNDS
WITH
UNUSUAL PROPERTIES
II
Literature Cited 1. 2. 3. 4. 5. 6. 7. 8. 9.
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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.
King; Inorganic Compounds with Unusual Properties—II Advances in Chemistry; American Chemical Society: Washington, DC, 1979.
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.
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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.
King; Inorganic Compounds with Unusual Properties—II Advances in Chemistry; American Chemical Society: Washington, DC, 1979.