9 Polymerization of Conjugated Dienes with Heterogeneous Ziegler-Natta Catalysts NORMAN G. GAYLORD Gaylord Associates Inc., 20 Mt. Pleasant Ave., Newark 4, N. J. HERMAN F. MARK
Downloaded by PENNSYLVANIA STATE UNIV on May 31, 2012 | http://pubs.acs.org Publication Date: January 1, 1962 | doi: 10.1021/ba-1962-0034.ch009
Polytechnic Institute of Brooklyn, Brooklyn 1, Ν. Y.
The structure of the polymer obtained in the poly merization of butadiene and isoprene with hetero geneous Ziegler-Natta catalysts depends on the nature of the monomer, catalyst system, and re action conditions.
Previously reported results are
reviewed and a mechanism is proposed for the stereoregulated dienes. with
polymerization
of
conjugated
The polymerization of cyclopentadiene
LiAlH -TiCl 4
4
or
LiAlR -TiCl 4
4
catalyst
system
yields a readily oxidized polymer for which a 1,2structure is proposed.
T h e structure of the polymer obtained b y the polymerization of butadiene, iso prene, and other dienes w i t h organometallic catalysts depends on the nature of the monomer, the catalyst system, and reaction conditions. I n this article, the authors review and propose a mechanism for some of the previously reported results on the polymerization of butadiene and isoprene and present some new data on the polymerization of cyclopentadiene. Butadiene and Isoprene Polymerization T h e polymerization of butadiene a n d isoprene w i t h an organometallic com pound-transition metal compound Ziegler-Natta type catalyst can lead to polymers w i t h a microstructure w h i c h is a l l cis-1,4-, trans-1,4-, isotatic 1,2- (or 3,4-), syndiotactic 1,2- (or 3,4-), or a combination of two or more of these structural units. T h e polymer microstructure may be dependent upon the ratio of the catalyst components, the temperature, and the reaction medium. Table I indicates the microstructure of polybutadienes prepared b y means of the indicated catalyst systems. It shows that at some given ratio of components, not necessarily at a l l ratios, a particular catalyst system is capable of yielding poly mer w i t h the indicated structural composition. T h e patent literature, i n some cases, contains conflicting data, indicating the influence of unspecified, and pos sibly unknown, factors. 127 In POLYMERIZATION AND POLYCONDENSATION PROCESSES; PLATZER, N.; Advances in Chemistry; American Chemical Society: Washington, DC, 1962.
128
ADVANCES IN CHEMISTRY SERIES Table I.
Butadiene Polymerization with Ziegler-Natta Catalysts
Catalyst Composition AlR + TiCl AlR + TiCl A1R + Tiï A1R + VC1 A1R + VC1 A1R + Ti(OR) A1R + TiAc « LiAlH + TiCl LiAlH + TiI CdR + TiCl Titanium acetylacetonate. 3
3
3
4
3
4
3
3
3
4
3
4
4
4
2
4
Ref. W (7 (W
+ , + + +
3
4
Downloaded by PENNSYLVANIA STATE UNIV on May 31, 2012 | http://pubs.acs.org Publication Date: January 1, 1962 | doi: 10.1021/ba-1962-0034.ch009
+ +
Nature of Unsaturation cis-1,47,2-
4
3
0
trans- 7,4+ +
+ +
(7 WX (77) (
