Telomerization of Conjugated Diolefins with Aromatics and Olefins

10 Telomerization of Conjugated Diolefins with Aromatics and Olefins Using Chelated Organosodium Catalysts

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WILLIAM BUNTING and ARTHUR W. LANGER, JR. Corporate Research Laboratories, Esso Research and Engineering C o . , L i n d e n , N . J . 07060

Telomerization of butadiene and isoprene with aromatics and olefins proceeds rapidly at 0°-100°C using organosodium catalysts in combination with aliphatic tertiary chelating polyamines containing two to six nitrogens. The products range from monoadduct up to tacky semisolids. Chain transfer increased with increasing complexing ability of the chelating agent, increasing chelating agent concentration, increasing acidity of the telogen, increasing temperature, and decreasing monomer concentration. More than 74 mole % selectivity to pentenylbenzene was obtained from butadiene and toluene. The ratio of alpha/internal unsaturation in the monoadduct varied from 0.5 to 1.7, and it decreased at the higher temperatures because of the double bond isomerization activity of the catalyst. Catalyst efficiencies greater than 1300 grams/gram benzylsodium were obtained.

A nionic telomerizations of conjugated diolefins with hydrocarbon acids are known but suffer from very low catalytic efficiencies. Morton et al. (1) and, later, Pappas et al. (2) used unchelated organosodium compounds to telomerize conjugated diolefins with weak hydrocarbon acids but obtained very low catalyst efficiencies (about 5 grams/gram catalyst). More recently, the anionic telomerization of butadiene and toluene by sodium on oxide supports (3) and sodium in tetrahydrofuran (4) was studied;, also, a potassium amide/lithiated alumina catalyst was used to telomerize butadiene (5). Common organosodium compounds are generally insoluble in inert solvents, and this causes considerable difficulty in their preparation and 201 Langer; Polyamine-Chelated Alkali Metal Compounds Advances in Chemistry; American Chemical Society: Washington, DC, 1974.

202

POLYAMINE-CHELATED

ALKALI

M E T A L

COMPOUNDS

p u r i f i c a t i o n as w e l l as i n t h e i r use as catalysts a n d reagents.

I n earlier

w o r k w i t h o r g a n o l i t h i u m catalysts i t w a s f o u n d t h a t c h e l a t i n g t e r t i a r y diamines and higher polyamines formed e n h a n c e d reactivities. T h e prospects organosodium compounds this p a p e r .

s o l u b l e complexes

(6)

with

of o b t a i n i n g s i m i l a r results w i t h

s t i m u l a t e d the research t h a t is t h e subject of

S u b s t a n t i a l differences

between

l i t h i u m systems w e r e e x p e c t e d a n d f o u n d . amines a n d s o d i u m c o m p o u n d s

the chelated sodium

and

F o r example, chelating d i -

form only weak, unstable

a l t h o u g h t h e d i a m i n e s s h o w some effect o n o r g a n o s o d i u m

complexes catalysts i n

solution. Downloaded by AUBURN UNIV on November 15, 2016 | http://pubs.acs.org Publication Date: June 1, 1974 | doi: 10.1021/ba-1974-0130.ch010

T h i s r e p o r t covers the use of c h e l a t e d o r g a n o s o d i u m c o m p o u n d s n o v e l catalysts for t e l o m e r i z i n g c o n j u g a t e d

diolefins w i t h w e a k

c a r b o n acids s u c h as aromatics a n d olefins ( 7 ) .

T h e factors affecting the

c h a i n - t r a n s f e r r e a c t i o n w e r e of p a r t i c u l a r interest b e c a u s e one of objectives

as

hydro-

w a s to increase s e l e c t i v i t y t o l o w - m o l e c u l a r - w e i g h t

T h e p r o d u c t s are u s e f u l i n s y n t h e s i z i n g p l a s t i c i z e r alcohols,

our

species. flame

re-

tardants, a n d surface coatings. Discussion Chelated Organosodium

Compounds.

T h e chelated

organosodium

c o m p o u n d s u s e d i n the t e l o m e r i z a t i o n process consist of those by

aliphatic, tertiary, chelating polyamines.

complexed

I n general, any

organo-

s o d i u m c o m p o u n d s m a y b e u s e d that, w h e n c h e l a t e d , c a n i n i t i a t e p o l y m e r i z a t i o n of the diolefin. T h i s relates to c a r b a n i o n b a s i c i t y i n that the i n i t i a t i n g c a r b a n i o n m u s t h a v e c o m p a r a b l e or greater b a s i c i t y t h a n the a l l y l c a r b a n i o n f o r m e d f r o m t h e d i o l e f i n . P h e n y l s o d i u m a n d b e n z y l s o d i u m are t h e most u s e f u l .

A l k y l sodium compounds

are too r e a c t i v e to p e r m i t

p r e f o r m i n g the c o m p l e x w i t h o u t d e c o m p o s i n g the c h e l a t i n g agent.

How-

ever, t h e y c a n b e u s e d w h e n the c o m p l e x is f o r m e d i n the presence

of

m o n o m e r or a s u i t a b l e h y d r o c a r b o n a c i d to c o n v e r t the a l k y l a n i o n to a c a r b a n i o n of l o w e r a c t i v i t y . T h e p r e f e r r e d c h e l a t i n g agents are d e r i v a t i v e s of e t h y l e n e d i a m i n e , h i g h e r p o l y a m i n e s , a n d isomers.

T h e particular tertiary chelating poly-

a m i n e s d i s c u s s e d here together w i t h t h e i r a b b r e v i a t i o n s are ( t h e y are a l l permethylated polyamines ) : TMED:

tetramethylethylenediamine

PMDT:

pentamethyldiethylenetriamine

i s o - H M T T : tris- ( ^ - d i m e t h y l a m i n o e t h y l ) a m i n e H M T P : heptamethy ltetraethylenepentamine OMPH :

octamethylpentaethylenehexamine

T w o examples of c h e l a t e d o r g a n o s o d i u m c o m p o u n d s

are s h o w n i n F i g -

u r e 1.

Langer; Polyamine-Chelated Alkali Metal Compounds Advances in Chemistry; American Chemical Society: Washington, DC, 1974.

10.

BUNTING A N D LANGER

k

Me Me \ /

(

v%

\J

NMe2

N — -Na —

Na

Me

Ph

,NMe2 NMe2

M e

iso-HMTT*PhNa

PMDT*BzNa Figure 1.


203

Telomerization of Olefins

Two chelated organosodium compounds

Telomerization. T h e t e l o m e r i z a t i o n is r u n b y i n t r o d u c i n g gaseous b u t a d i e n e i n t o t h e a t m o s p h e r e a b o v e a s o l u t i o n o f catalyst i n t h e h y d r o c a r b o n a c i d u n d e r c o n d i t i o n s r i g o r o u s l y e x c l u d i n g a i r or w a t e r . T h e gaseous b u t a d i e n e m a y b e d i l u t e d w i t h a n i n e r t gas a n d b u b b l e d t h r o u g h the reactant s o l u t i o n . T o m a x i m i z e c o n v e r s i o n to l o w m o l e c u l a r - w e i g h t p r o d u c t s , efficient m i x i n g o f reagents is necessary. T h e r e a c t i o n p r o d u c t is i s o l a t e d b y w a s h i n g w i t h w a t e r a n d d i s t i l l i n g . T h e process is r e p r e sented i n F i g u r e 2 b y t h e t e l o m e r i z a t i o n o f toluenes a n d b u t a d i e n e . T h e i n i t i a l step i n v o l v e s attack of t h e c h e l a t e d o r g a n o s o d i u m o n t h e conjugated

d i o l e f i n to g i v e a n a l l y l a n i o n .

T h e a l l y l a n i o n c a n either

abstract a p r o t o n f r o m t h e h y d r o c a r b o n telogen

( t o l u e n e ) to g i v e t h e

m o n o a d d u c t o r a d d to another m o l e c u l e of d i o l e f i n to g i v e a n e w a l l y l Θ Na#Chel

Figure 2.

Telomerization of toluene and butadiene


204

POLYAMINE-CHELATED

ALKALI

M E T A L

COMPOUNDS

a n i o n . F u r t h e r , p r o t o n a b s t r a c t i o n o r d i o l e f i n attack c a n o c c u r at either t h e 1- or 3 - c a r b o n of t h e a l l y l a n i o n . T h e r e seems to b e a p o s i t i v e c o r r e l a t i o n b e t w e e n t h e r e l a t i v e r e a c t i v i t i e s of the 1- a n d 3-carbons i n p r o t o n a b s t r a c t i o n a n d i n p o l y m e r i z a t i o n . It is possible to v a r y the r a t i o of m o n o a d d u c t s I : I I (see F i g u r e 2 ) as w e l l as the average d e g r e e of p o l y m e r i z a t i o n of the r e a c t i o n b y v a r y i n g t h e r e a c t i o n c o n d i t i o n s a n d catalyst. R e m e t a l a t i o n of p r o d u c t s c a n o c c u r at b o t h b e n z y l i c a n d a l l y l i c positions to p r o d u c e a d d i t i o n a l b r a n c h e d t e l o m e r structures. A l t h o u g h t h e y w e r e not a l l i d e n t i f i e d , the n u m b e r of gas c h r o m a t o g r a p h i c

(GC)

peaks i n the d i a d d u c t f r a c t i o n i n d i c a t e d t h a t a l l e x p e c t e d s t r u c t u r a l a n d Downloaded by AUBURN UNIV on November 15, 2016 | http://pubs.acs.org Publication Date: June 1, 1974 | doi: 10.1021/ba-1974-0130.ch010

d o u b l e - b o n d isomers w e r e o b t a i n e d . N a t u r e of the Catalyst.

T h e effect of v a r y i n g t h e c h e l a t i n g agent

i n t o l u e n e - b u t a d i e n e t e l o m e r i z a t i o n is s h o w n i n T a b l e s I a n d I I .

The

use of t r i g l y m e ( a t e t r a e t h e r ) as a c h e l a t i n g agent gave a n i n a c t i v e Table I. Chelating Agent None TMED PMDT iso-HMTT HMTP OMPH triglyme

Effect of Chelating Agent,

Total Product (grams)

Selectivity to monoadduct, %

6.0 15.8 11.5 13.3 17.5 15.8 no reaction

34 32 26 45 60 59

40°C

e

Alpha/Internal Unsaturation 0.5 0.5 1.2 1.6 1.4 1.5

T o 2.63 mmoles benzylsodium were added 2.63 mmoles chelating agent and 50 ml toluene. The reaction was heated to 40°C and maintained at 40°C while 22 cc/min gaseous butadiene were introduced into the atmosphere above the reaction for 2 hrs. A t the end of that time 5 ml of water were added, and the organic layer separated and dried (K2CO3). Toluene was removed at water-aspirator pressure, and the residue was distilled (140°C/0.05 mm). The distillate was analyzed by G C . α

Table II. Chelating Agent None TMED PMDT iso-HMTT HMTP α

Effect of Chelating Agent,

Total Product (grams)

Selectivity to Monoadduct, %

50 m g ( w a x y solid) 11.8 9.5 8.6 11.2

0 41.5 18 6.2 22.5

5°C

e

Alpha/Internal Unsaturation — 0.21 0.85 1.72 1.5

Same reaction conditions as in Table I except the reaction temperature was 5°C.

catalyst.

P r e s u m a b l y t h e c a t a l y s t d e c o m p o s e d via m e t a l a t i o n of

the

c h e l a t i n g agent. I n terms of s e l e c t i v i t y to m o n o a d d u c t a n d a l p h a / i n t e r n a l u n s a t u r a t i o n at 4 0 ° C , the T M E D - B z N a gives results s i m i l a r to b e n z y l s o d i u m a l o n e whereas complexes c o n t a i n i n g the h i g h e r c h e l a t i n g agents


10.

BUNTING

AND

LANGER

205

Τ elomenzation of Olefins

differ m a r k e d l y f r o m b e n z y l s o d i u m

alone.

T h i s is a reflection of

the

r e l a t i v e s t a b i l i t y of the complexes. A t 4 0 ° C , T M E D - B z N a is a r e l a t i v e l y weak

complex

while

PMDT-BzNa

and

the

complexes

with

higher

c h e l a t i n g agents are r e l a t i v e l y strong complexes. As shown i n Tables I and II, unchelated less r e a c t i v e t h a n is the c h e l a t e d

benzylsodium

benzylsodium.

Ignoring

is

much

colligative

properties there are several g e n e r a l explanations for the n a t u r e of

the

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

organosodium

c o m p o u n d s is p a r t of a n y e x p l a n a t i o n c o m p a r i n g c h e l a t e d w i t h u n c h e l a t e d Downloaded by AUBURN UNIV on November 15, 2016 | http://pubs.acs.org Publication Date: June 1, 1974 | doi: 10.1021/ba-1974-0130.ch010

s o d i u m c o m p o u n d s . M o r e o v e r , s u r r o u n d i n g the s o d i u m c a t i o n b y a L e w i s base ( t h e c h e l a t i n g a g e n t ) m i g h t b e e x p e c t e d to increase the

electron

d e n s i t y o n the a n i o n , m a k i n g the a n i o n i n a chelated, s o d i u m c o m p o u n d a stronger base r e l a t i v e to t h e a n i o n i n a n u n c h e l a t e d s o d i u m c o m p o u n d (8, 9 ) .

T h e m o r e c h e l a t i n g g r o u p s s u r r o u n d i n g the c a t i o n , the greater

s h o u l d be the c h a r g e p o l a r i z a t i o n of the c a r b o n - s o d i u m

bond.

A s the

c h a r g e d e n s i t y o n the i n t e r m e d i a t e a l l y l a n i o n i n v o l v e d i n the t e l o m e r i z a t i o n ( F i g u r e 3 ) increases, the r e l a t i v e reactivities of the 1- a n d 3-carbons i n p r o t o n a b s t r a c t i o n a n d p o l y m e r i z a t i o n w o u l d b e e x p e c t e d to c h a n g e i n a d i r e c t i o n i n c r e a s i n g t h e r e l a t i v e r e a c t i v i t y of the 3 - c a r b o n , w h i c h f u n d a m e n t a l l y agrees w i t h the d a t a g i v e n i n T a b l e s I a n d I I .

Figure 3.

Allyl anion intermediate in toluene-butadiene telomerization

U n d o u b t e d l y , greater c h a r g e p o l a r i z a t i o n i n the m e t a l - c a r b o n occurs i n the c h e l a t e d c o m p o u n d s .

However,

how

bond

significant this i n

creased c h a r g e p o l a r i z a t i o n is w i t h a n a l r e a d y h i g h l y i o n i c species is a moot question.

W h e r e a s the o r g a n o l i t h i u m c o m p o u n d s are u s u a l l y c o n

s i d e r e d to b e f a i r l y covalent

i n nature, the organosodium

are u s u a l l y t h o u g h t of as h i g h l y i o n i c species

compounds

(10).

A n o t h e r possible e x p l a n a t i o n of the results invokes steric effects i n the i n t e r m e d i a t e a l l y l a n i o n ( F i g u r e 3 ) .

T h e steric i n t e r a c t i o n b e t w e e n

the b u l k y c h e l a t e d c a t i o n a n d the b e n z y l g r o u p p r o b a b l y

pushes


the

206

POLYAMINE-CHELATED

ALKALI

M E T A L

COMPOUNDS

c h e l a t e d c a t i o n t o w a r d the 1-carbon, i n c r e a s i n g the steric s h i e l d i n g a b o u t t h e 1-carbon r e l a t i v e to the 3 - c a r b o n .

C o n s e q u e n t l y , i n g o i n g to h i g h e r

c h e l a t i n g agents t h e c h e l a t e d c a t i o n b e c o m e s i n c r e a s i n g l y b u l k y a n d t h e 3 - c a r b o n b e c o m e s m o r e r e a c t i v e r e l a t i v e to t h e 1-carbon i n p r o t o n a b straction (manifested b y increasing a l p h a / i n t e r n a l unsaturation i n Tables I a n d I I ) . M o r e o v e r , t h e steric r e q u i r e m e n t s f o r r e a c t i o n w i t h b u t a d i e n e ( p o l y m e r i z a t i o n ) s h o u l d b e greater t h a n p r o t o n e x t r a c t i o n f r o m toluene (chain transfer).

C o n s e q u e n t l y , s e l e c t i v i t y to m o n o a d d u c t

should i n -

crease w i t h h i g h e r c h e l a t i n g agents. T h e d a t a i n T a b l e s I a n d I I are f o l l o w e d q u i t e w e l l w i t h a l p h a / Downloaded by AUBURN UNIV on November 15, 2016 | http://pubs.acs.org Publication Date: June 1, 1974 | doi: 10.1021/ba-1974-0130.ch010

i n t e r n a l u n s a t u r a t i o n a n d w i t h s e l e c t i v i t y to m o n o a d d u c t

(Table

C o n v e r s i o n to m o n o a d d u c t , t h o u g h , is n o t w e l l f o l l o w e d at 5 ° C

I).

(Table

I I ) . T h i s m a y b e because of a t e m p e r a t u r e - d e p e n d e n t c h a n g e i n c o l l i g a t i v e p r o p e r t i e s , l o w e r t e m p e r a t u r e f a v o r i n g h i g h e r states of a g g r e g a t i o n . W e h a v e n o m o l e c u l a r - w e i g h t d a t a for c h e l a t e d o r g a n o s o d i u m

com-

p o u n d s i n s o l u t i o n . H o w e v e r , L a n g e r has m e a s u r e d the m o l e c u l a r w e i g h t s of s e v e r a l c h e l a t e d o r g a n o l i t h i u m c o m p o u n d s i n h y d r o c a r b o n s o l u t i o n (II).

H e f o u n d T M E D - n - B u L i to b e m o n o m e r i c at 0 . 1 M a n d

LiCHPh

2

TMED-

to v a r y c o n s i d e r a b l y i n a g g r e g a t i o n state w i t h c h a n g e i n c o n -

c e n t r a t i o n , b e i n g m o n o m e r i c o n l y at l o w c o n c e n t r a t i o n ( 0 . 0 5 M ) .

The

chelated organosodium compounds probably behave like the h i g h l y ionic c h e l a t e d d i p h e n y l m e t h y l l i t h i u m . C o n s e q u e n t l y , a g g r e g a t i o n states greater t h a n one are p r o b a b l y i m p o r t a n t i n catalysis of the t e l o m e r i z a t i o n , p a r t i c u l a r l y at l o w temperatures a n d h i g h catalyst concentrations. A m o d e l f o r the c a t a l y s t s t r u c t u r e i n v o l v i n g c o l l i g a t i v e p r o p e r t i e s , i o n i c c h a r a c t e r , a n d steric effects is p r o b a b l y necessary b e f o r e w e c a n k n o w t h e i n t i m a t e details of the m e c h a n i s m of the t e l o m e r i z a t i o n r e a c t i o n . Nonstoichiometric Catalyst.

B e n e f i c i a l results i n o p t i m i z i n g selec-

t i v i t y to l o w - m o l e c u l a r - w e i g h t t e l o m e r c a n be o b t a i n e d b y d e v i a t i n g f r o m the 1:1 s t o i c h i o m e t r y of o r g a n o s o d i u m c o m p o u n d s to c h e l a t i n g agent. Table III. Mmoles iso-HMTT 2.63 5.26 5.26 10.52 10.52 2.63

Nonstoichiometric Catalyst Total Product, grams

Mmoles BzNa 2.63 2.63 5.26 2.63 5.26 10.52

1 2 1 4 2 0.25

29.3 38.8 39.8 40.3 40.1 39.7

Compositions

a

Selectivity Alpha/ Internal to Monoadduct, % Unsaturation 1.2 50 1.52 65.8 73.2 1.25 1.41 66.8 74.4 1.16 0.61 63.8

Butadiene 50 cc/min, was bubbled for 2 hr into 250 ml toluene containing the catalyst at 40°C. The reaction was quenched with 5 ml of water. Yields are distilled yields. Molar ratio of chelating agent to benzylsodium a

6


10.

BUNTING

AND

207


LANGER

D a t a for n o n s t o c h i o m e t r i c c a t a l y s t c o m p o s i t i o n s are s h o w n i n T a b l e I I I . I n t h e p r e c e d i n g section the l a r g e differences b e t w e e n T M E D - B z N a at 5 ° C ( T a b l e I I ) a n d 4 0 ° C ( T a b l e I ) are b r i e f l y discussed i n terms of the s t r e n g t h of the c o m p l e x .

A t 40°C T M E D - B z N a

behaves

much

u n c h e l a t e d b e n z y l s o d i u m i n the t e l o m e r i z a t i o n whereas at 5 ° C

like

TMED-

B z N a differs m a r k e d l y f r o m b e n z y l s o d i u m . A t h i g h e r t e m p e r a t u r e s the c o m p l e x b e t w e e n c h e l a t i n g agent a n d s o d i u m c o m p o u n d is m o r e disso ciated.

T h i s e q u i l i b r i u m c a n be forced

to the r i g h t b y a d d i n g m o r e

c h e l a t i n g agent o r m o r e s o d i u m c o m p o u n d :


Chel + N a X

chel-NaX

K

e q

. =

^

ίΐ^Γ^ν! [chel] [N a A J

U n f o r t u n a t e l y , b o t h excess s o d i u m c o m p o u n d a n d c h e l a t e d s o d i u m compound

c a t a l y z e the t e l o m e r i z a t i o n , e v e n w h e n the f o r m e r is less

effective, a n d i t is difficult to separate these t w o reactions. W i t h excess c h e l a t i n g agent, h o w e v e r , the e q u i l i b r i u m shift is clear.

T h e data i n

T a b l e I I I for excess c h e l a t i n g agent s u p p o r t t h e c o n c e p t of a c h e l a t e d s o d i u m c o m p o u n d i n e q u i l i b r i u m w i t h free c h e l a t i n g agent a n d s o d i u m compound.

It is also possible, p a r t i c u l a r l y b e l o w 25 ° C , that c a t a l y t i c

species of s t o i c h i o m e t r y c h e l N a X or c h e l ( N a X ) 2

2

are i n v o l v e d i n a d d i t i o n

to c h e l - N a X i n the t e l o m e r i z a t i o n r e a c t i o n . Effect of Temperature and Butadiene Concentration. I n c r e a s i n g t h e r e a c t i o n t e m p e r a t u r e increases the c h a i n - t r a n s f e r rate faster t h a n the p o l y m e r i z a t i o n rate ( T a b l e I V ) . A c t i v a t i o n e n e r g y for c h a i n transfer is p r o b a b l y h i g h e r t h a n that f o r p o l y m e r i z a t i o n a l t h o u g h the l o w e r s o l u b i l i t y of b u t a d i e n e at the h i g h e r temperatures w o u l d also c o n t r i b u t e to the same result. Table IV. Temperature

°C

5 40 70

Effect of Reaction Temperature

Telomer Yield, grams


8.6 13.3 15.0

6.2 45 67

Alpha/Internal Unsaturation 1.7 1.6 0.9

I n c r e a s i n g the r e a c t i o n t e m p e r a t u r e n o t o n l y increases

conversions

to m o n o a d d u c t b u t also decreases catalyst l i f e t i m e a n d isomerizes the product.

U n d e r f a v o r a b l e c o n d i t i o n s , m o r e t h a n 1300 grams

gram B z N a were 110°C

obtained.

product/

A g i n g the catalyst, i s o - H M T T - B z N a ,

for f o u r h o u r s results i n a n i n a c t i v e catalyst.

at

P r e s u m a b l y the

catalyst s l o w l y decomposes via m e t a l a t i o n a n d d e c o m p o s i t i o n

of

the

c h e l a t i n g agent as w a s s h o w n for the c h e l a t e d a l k y l l i t h i u m catalysts. T h a t t h e decrease i n a l p h a / i n t e r n a l u n s a t u r a t i o n w i t h i n c r e a s i n g tern-


208

P O LYA M I N E - C H E L A T E D

4

M E T A L

COMPOUNDS

Effect of Butadiene Addition Rate

Table V . C # Rate (cc/min)

ALKALI


6

Time

22 44 66 110

(min)

Alpha/Internal Unsaturation 0.88 0.91 1.03 1.35

67 63 59 57

120 60 40 24

p e r a t u r e results i n p a r t f r o m p r o d u c t i s o m e r i z a t i o n a n d n o t o n l y f r o m some f u n d a m e n t a l c h a n g e i n t h e n a t u r e of t h e c a t a l y s t ( d i s s o c i a t i o n ) is s h o w n i n T a b l e V . A d d i n g a constant a m o u n t o f b u t a d i e n e , b u t i n Downloaded by AUBURN UNIV on November 15, 2016 | http://pubs.acs.org Publication Date: June 1, 1974 | doi: 10.1021/ba-1974-0130.ch010

shorter r e a c t i o n t i m e s , increases a l p h a / i n t e r n a l u n s a t u r a t i o n . A l s o , i n c r e a s i n g t h e effective

b u t a d i e n e c o n c e n t r a t i o n decreases s e l e c t i v i t y to

m o n o a d d u c t as expected. Scope of the Reaction. Isoprene also has b e e n successfully u s e d ; i t gives

s l i g h t l y h i g h e r s e l e c t i v i t y to m o n o a d d u c t

t h a n does

butadiene

u n d e r i d e n t i c a l r e a c t i o n c o n d i t i o n s , reflecting t h e s l i g h t l y l o w e r r e a c t i v i t y of i s o p r e n e i n t h e t e l o m e r i z a t i o n . B e n z e n e a n d octene h a v e b e e n u s e d to r e p l a c e toluene. T h e y give h i g h e r m o l e c u l a r w e i g h t telomers, r e f l e c t i n g a s l o w e r c h a i n - t r a n s f e r step b e c a u s e o f t h e l o w e r a c i d i t y o f a l l y l i c a n d a r o m a t i c protons r e l a t i v e to t h e b e n z y l i c protons o n toluene (12).

Also,

the o r g a n o s o d i u m c o m p o n e n t of t h e catalyst has b e e n r e p l a c e d e n t i r e l y o r i n p a r t b y t h e analogous o r g a n o l i t h i u m c o m p o u n d .

I n general the

presence of o r g a n o l i t h i u m c o m p o u n d s i n t h e t e l o m e r i z a t i o n process gives t e l o m e r o f m a r k e d l y h i g h e r m o l e c u l a r w e i g h t because o r g a n o l i t h i u m c o m p o u n d s u n d e r g o c h a i n - t r a n s f e r t y p e reactions m u c h s l o w e r t h a n d o organosodium compounds.

T h e s e reactions are s u m m a r i z e d i n T a b l e V I .

Preparation of O x o Alcohols. A t e l o m e r p r o d u c t c o n t a i n i n g a b o u t e q u a l a m o u n t s o f a l p h a a n d i n t e r n a l olefin m o n o a d d u c t s

was hydro-

f o r m y l a t e d u s i n g c o b a l t o c t a c a r b o n y l at 120 °C a n d 3000 p s i g , y i e l d i n g a 6 0 % c o n v e r s i o n to a l d e h y d e s . Table V I . Taxogen Telogen RM

isoprene toluene BzLi

C h e l a t i n g agent P M D T Temperature, °C Time, min Selectivity to monoadduct, % M n

T h e aldehydes were reduced to their

Miscellaneous

C4H6

1-octene C HnNa 5

isoHMTT

40 120

40 120

trace 2549

trace 2422

Telomerizations

C4H6

toluene BzLi/ BzNa TMED

40 120

8.6

isoprene toluene BzNa

C4H6

benzene C H Na 6

5

isoHMTT

iso-HMTT

70 80

70 120

64

low 998


10.

BUNTING

AND

209


LANGER

c o r r e s p o n d i n g alcohols w i t h T M E D - L i A l H

4

i n benzene

(13).

three alcohols p r o d u c e d a b o u t 6 0 % w a s 6 - p h e n y l - l - h e x a n o l .

Of

the

T h e other

t w o alcohols are p r o b a b l y 5 - p h e n y l - 2 - m e t h y l - l - p e n t a n o l a n d 4 - p h e n y l - 2 ethyl-l-butanol.

B y c o n v e r t i n g these alcohols to p h t h a l a t e esters,

low

v o l a t i l i t y p l a s t i c i z e r s are o b t a i n e d .


Experimental R e a c t i o n s w e r e r u n u n d e r c o n d i t i o n s r i g o r o u s l y e x c l u d i n g a i r or moisture. H y d r o c a r b o n solvents w e r e p u r i f i e d b y passage t h r o u g h a n a l u m i n a c o l u m n a n d storage over s o d i u m r i b b o n b e f o r e use. C h e l a t i n g agents w e r e d r i e d ( s o d i u m r i b b o n ) , f r a c t i o n a l l y d i s t i l l e d , a n d stored over calcium hydride. Organosodium compounds were obtained from Orgmet (Hampstead, N . H . ) a n d used without further purification. General Telomerization. O r g a n o m e t a l l i c c o m p o u n d a n d solvent w e r e a d d e d to a d r i e d flask e q u i p p e d w i t h a s t i r r i n g b a r i n a d r y box. T h e r e a c t i o n flask w a s s t o p p e r e d or fitted w i t h a t h e r m o m e t e r a n d r e m o v e d f r o m the d r y box. T h e r e a c t i o n w a s p l a c e d u n d e r n i t r o g e n a n d h e a t e d ( o r c o o l e d ) to the d e s i r e d t e m p e r a t u r e . T h e c o n j u g a t e d d i o l e f i n w a s t h e n a d d e d b y i n t r o d u c i n g it i n t o t h e atmosphere a b o v e t h e s o l u t i o n , b u b b l i n g t h r o u g h the r e a c t i o n s o l u t i o n , o r d i s s o l v i n g i n a n a p p r o p r i a t e solvent, a n d a d d i n g the r e s u l t a n t s o l u t i o n d r o p w i s e . A t the e n d of t h e d e s i r e d r e a c t i o n p e r i o d , 5-10 m l of w a t e r w e r e a d d e d w i t h s t i r r i n g . T h e o r g a n i c l a y e r w a s d r i e d ( K C 0 ) a n d either f r a c t i o n a l l y d i s t i l l e d at w a t e r - a s p i r a t o r pressure ( b p of m o n o a d d u c t is a b o u t 1 1 5 - 1 2 0 ° C / 1 5 m m , d i a d d u c t a b o u t 1 7 5 ° C ) or b u l b - t o - b u l b d i s t i l l e d ( 1 4 0 ° C / 0 . 0 2 m m ) . D i s t i l l a t e s w e r e a n a l y z e d o n a C a r b o w a x - 2 0 M c o l u m n at a b o u t 1 8 0 ° C . T h e monoadducts were characterized b y N M R and IR. Chelated Organolithium Catalyst. T o 1.6 m l of 1.6N n - b u t y l l i t h i u m i n hexane w e r e a d d e d 50 m l toluene a n d 0.6 m l P M D T , g e n e r a t i n g P M D T - B z L i in situ. T h e r e a c t i o n was k e p t at 4 0 ° C w h i l e b u t a d i e n e w a s i n t r o d u c e d i n t o the a t m o s p h e r e a b o v e the r e a c t i o n (22 c c / m i n ) for 2 hrs. T h e r e a c t i o n w a s t h e n q u e n c h e d w i t h 5 m l of w a t e r . T h e o r g a n i c l a y e r w a s separated, d r i e d ( K C 0 ) , a n d the solvent w a s r e m o v e d u n d e r v a c u u m to give 5 grams of p r o d u c t h a v i n g M = 2549. Chelated Organolithium/Organosodium Catalyst. T o 0.95 m l of 1.62V n - b u t y l l i t h i u m (1.5 m m o l e s ) w e r e a d d e d 50 m l t o l u e n e , 0.17 grams (1.5 m m o l e s ) b e n z y l s o d i u m , a n d 0.45 m l (— 3 m m o l e s ) T M E D . T h e r e a c t i o n w a s h e a t e d to 40 ° C a n d k e p t at that t e m p e r a t u r e w h i l e gaseous b u t a d i e n e was i n t r o d u c e d (22 c c / m i n ) i n t o the a t m o s p h e r e a b o v e the r e a c t i o n for 2 h r . T h e r e a c t i o n w a s t h e n q u e n c h e d w i t h 5 m l of w a t e r , a n d the o r g a n i c l a y e r s e p a r a t e d a n d d r i e d ( K C 0 ) . T h e toluene w a s r e m o v e d at w a t e r - a s p i r a t o r pressure, a n d the r e s i d u e was d i s t i l l e d ( 1 4 0 ° C / 0 . 0 5 m m ) . T h e d i s t i l l a t e was a n a l y z e d b y G C . T o t a l p r o d u c t w e i g h t was 6.1 grams. S e l e c t i v i t y to m o n o a d d u c t w a s 8 . 6 % . T h e r a t i o of a l p h a - t o - i n t e r n a l u n s a t u r a t i o n w a s 1.25. Telomerization of Toluene and Isoprene. T o 0.3 g r a m b e n z y l s o d i u m w e r e a d d e d 50 m l of t o l u e n e a n d 0.7 m l of i s o - H M T T . A s o l u t i o n of 20 m l isoprene i n 25 m l toluene w a s a d d e d d r o p w i s e to this r e a c t i o n m i x t u r e at 70 ° C over 80 m i n . A w o r k - u p s i m i l a r to the p r e c e d i n g e x a m p l e w a s 2

3

P

2

3

n

2

3


210

POLYAMINE-CHELATED

ALKALI

M E T A L

COMPOUNDS

used. T h e t o l u e n e - i s o p r e n e t e l o m e r w e i g h e d 23.8 grams. S e l e c t i v i t y t o m o n a d d u c t w a s 6 4 % b a s e d o n G C analysis. Telomerization of Benzene and Butadiene. T o 0.26 g r a m ( 2 . 6 3 m m o l e s ) o f p h e n y l s o d i u m w e r e a d d e d 5 0 m l o f b e n z e n e a n d 0.7 m l of i s o - H M T T . T h e r e a c t i o n w a s k e p t at 70 ° C w h i l e b u t a d i e n e w a s i n t r o d u c e d i n t o t h e a t m o s p h e r e a b o v e t h e r e a c t i o n f o r 2 hrs at 2 2 c c / m i n . A w o r k - u p s i m i l a r t o t h a t g i v e n u n d e r c h e l a t e d o r g a n o l i t h i u m catalyst gave 7 grams o f b e n z e n e b u t a d i e n e t e l o m e r w i t h M = 998. Telomerization of 1-Octene and Butadiene. T o 0.3 g r a m o f n - a m y l s o d i u m w e r e a d d e d 50 m l o f 1-octene a n d 0.7 m l o f i s o - H M T T . B u t a d i e n e gas w a s a d d e d t o this r e a c t i o n m i x t u r e a t 40 ° C at 2 2 c c / m i n f o r 2 h r . A w o r k - u p s i m i l a r t o t h a t g i v e n u n d e r c h e l a t e d o r g a n o l i t h i u m catalyst gave 4.6 grams o f o c t e n e - b u t a d i e n e t e l o m e r w i t h M = 2422. n


n

Literature Cited 1. Morton, Α., Patterson, G. H., Donovan, J. P., Little, E . L., J. Amer. Chem. Soc. (1946) 68, 93. 2. Pappas, J. J., Schriesheim, Α., U.S. Patent 3,189,660 (1965). 3. Eberhardt, G. G., Peterson, H . J., J. Org. Chem. (1965) 30, 82. 4. Kume, S., et al., Makromol. Chem. (1966) 98, 109; Kume, S., Makromol. Chem. (1966) 98, 120. 5. Bloch, H . S., U.S. Patent 3,355,484 (1967). 6. Langer, A. W., U.S. Patent 3,541,149 (1970); U.S. Patent 3,451,988 (1969). 7. Bunting, W., Langer, A W., U.S. Patent 3,750,200 (1972); U.S. Patent 3,742,057 (1973). 8. Originally proposed to account for the unusual reactivity of TMED-n-BuLi: Langer, A. W., Am. Chem. Soc. Div. Polymer Chem. Preprints (1966) 137. 9. Langer, A. W., Trans. Ν.Y. Acad. Sci. (1965) 27, 746. 10. Cotton, F. Α., Wilkinson, G., "Advanced Inorganic Chemistry," Interscience, New York, 1962. 11. Langer, A. W., unpublished results. 12. Cram, D. J., "Fundamentals of Carbanion Chemistry," p. 19, Academic, New York. 1965. 13. Langer, A. W., Whitney, Τ. Α., Chem. Abstr. (1971) 75, 38572Z; U.S. Patent 3,734,963 (1973). RECEIVED March 13, 1973.


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