production with single-site catalysts, this concept has also led to the first industrial
production and market introduction of syndiotactic polypropylene by former Fina Inc.
(today TOTAL Petrochemicals & Refining USA, Inc.) and of ethene/norbornene
copolymers by former Hoechst AG (today TOPAS Advanced Polymers).
The possibility of preventing the mutual rotation of the ring ligands [4, 5] and
to vary the interanular wedge angle [16] has secured for ansa-metallocenes an
important role in metallocene-produced polyethylene, together with simple
unbridged metallocenes and non-metallocene single-site catalysts. Even Dow’s
“constrained-geometry catalysts”, where a bridge links cyclopentadienyl-type with
non-cyclopentadienyl-type (e.g. alkylamido) ligands to form a half-sandwich complex with a titanium center [80, 81], to become the basis for DOW’s INSITE™
technology and ENGAGE™ polyolefin elastomer product line, might thus be
regarded as evolutions of the ansa-metallocene concept.
The role of ansa-metallocenes for the industrial production of i-PP (initially the
primary aim of their development) is still limited to specialized niche applications
with relatively small market shares and thus – ironically – is less important than for
other polymers such as m-LLDPE. Besides the specifics of isotactic propene homopolymers and their applications in injection molding and BOPP, higher costs for the
use of ansa-metallocene catalysts and rather severe patent hurdles have limited
their full success in industrial i-PP production so far. However, LyondellBasell and
Lummus Novolen Technology GmbH, the two active licensors of metallocene
technology for the isospecific polymerization of propene, have both reported the
development of highly active ansa-metallocene catalysts for i-PP, which reduces
the cost gap between such catalysts and modern Ziegler–Natta catalysts [82, 83]. At
the same time, many of the basic patents, by which access to ansa-metallocene
technology for i-PP had been limited to only a handful of players, have now expired
or will expire in the near future. It will be interesting to see whether this will finally
open the path for a wider use of ansa-metallocene catalysts in the industrial
production of i-PP.
Acknowledgments We thank Rendiconti Lincei: Scienze Fisiche e Naturali for permission to use
for this review materials published in [66] and Deutsche Forschungsgemeinschaft for support of
research in this field at the University of Konstanz (grant Me 1388/9-1).
References
1. Wild F, Zsolnai L, Huttner G, Brintzinger HH (1982) J Organomet Chem 232:233
2. Wild F, Wasiucionek M, Huttner G, Brintzinger HH (1985) J Organomet Chem 288:63
3. Sinn H, Kaminsky W (1980) Adv Organomet Chem 18:99
4. Ewen JA (1984) J Am Chem Soc 106:6355
5. Kaminsky W, Ku ¨lper K, Brintzinger HH, Wild F (1985) Angew Chem Int Ed Engl 24:507
6. Llinas GH, Day RO, Rausch MD, Chien JCW (1993) Organometallics 12:1283
7. Resconi L, Cavallo L, Fait A, Piemontesi F (2000) Chem Rev 100:1253
8. Resconi L, Chadwick JC, Cavallo L (2007) In: Crabtree RH, Mingos DMP (eds) Comprehensive organometallic chemistry III, vol 4. Elsevier, Amsterdam, p 1005
40
H.H. Brintzinger and D. Fischer
production and market introduction of syndiotactic polypropylene by former Fina Inc.
(today TOTAL Petrochemicals & Refining USA, Inc.) and of ethene/norbornene
copolymers by former Hoechst AG (today TOPAS Advanced Polymers).
The possibility of preventing the mutual rotation of the ring ligands [4, 5] and
to vary the interanular wedge angle [16] has secured for ansa-metallocenes an
important role in metallocene-produced polyethylene, together with simple
unbridged metallocenes and non-metallocene single-site catalysts. Even Dow’s
“constrained-geometry catalysts”, where a bridge links cyclopentadienyl-type with
non-cyclopentadienyl-type (e.g. alkylamido) ligands to form a half-sandwich complex with a titanium center [80, 81], to become the basis for DOW’s INSITE™
technology and ENGAGE™ polyolefin elastomer product line, might thus be
regarded as evolutions of the ansa-metallocene concept.
The role of ansa-metallocenes for the industrial production of i-PP (initially the
primary aim of their development) is still limited to specialized niche applications
with relatively small market shares and thus – ironically – is less important than for
other polymers such as m-LLDPE. Besides the specifics of isotactic propene homopolymers and their applications in injection molding and BOPP, higher costs for the
use of ansa-metallocene catalysts and rather severe patent hurdles have limited
their full success in industrial i-PP production so far. However, LyondellBasell and
Lummus Novolen Technology GmbH, the two active licensors of metallocene
technology for the isospecific polymerization of propene, have both reported the
development of highly active ansa-metallocene catalysts for i-PP, which reduces
the cost gap between such catalysts and modern Ziegler–Natta catalysts [82, 83]. At
the same time, many of the basic patents, by which access to ansa-metallocene
technology for i-PP had been limited to only a handful of players, have now expired
or will expire in the near future. It will be interesting to see whether this will finally
open the path for a wider use of ansa-metallocene catalysts in the industrial
production of i-PP.
Acknowledgments We thank Rendiconti Lincei: Scienze Fisiche e Naturali for permission to use
for this review materials published in [66] and Deutsche Forschungsgemeinschaft for support of
research in this field at the University of Konstanz (grant Me 1388/9-1).
References
1. Wild F, Zsolnai L, Huttner G, Brintzinger HH (1982) J Organomet Chem 232:233
2. Wild F, Wasiucionek M, Huttner G, Brintzinger HH (1985) J Organomet Chem 288:63
3. Sinn H, Kaminsky W (1980) Adv Organomet Chem 18:99
4. Ewen JA (1984) J Am Chem Soc 106:6355
5. Kaminsky W, Ku ¨lper K, Brintzinger HH, Wild F (1985) Angew Chem Int Ed Engl 24:507
6. Llinas GH, Day RO, Rausch MD, Chien JCW (1993) Organometallics 12:1283
7. Resconi L, Cavallo L, Fait A, Piemontesi F (2000) Chem Rev 100:1253
8. Resconi L, Chadwick JC, Cavallo L (2007) In: Crabtree RH, Mingos DMP (eds) Comprehensive organometallic chemistry III, vol 4. Elsevier, Amsterdam, p 1005
40
H.H. Brintzinger and D. Fischer