POLYPROPYLENE AND CATALYSTS

POLYPROPYLENE AND CATALYSIS

(A Tribute to Prof Robert H Grubbs, Winner of the 2005 Noble Prize in Chemistry)

DR VIRENDRA K GUPTA

Polypropylene (PP) is a commercially important thermoplastic used in a variety of applications in growth sectors such as health, transport, packaging, infrastructure, agriculture, defense, energy etc. The global market is forecasted to grow to around 90.7 million metric tons by 2026 from approximately 74 million metric tons in 2020 (1-3). Polypropylene is produced by polymerization of propylene for homo grades while copolymerization with olefins lead to the production of copolymers categorized as random and impact polymer grades. LyondellBasell, Sinopec Group, SABIC, PetroChina Group, Braskem Group, Reliance Industries Ltd, IPIC Group, Total PC, ExxonMobil, Formosa Plastics are some of the leading producers of polypropylene in the world. In India, Many other producers have also become part of polypropylene industry such as Indian Oil Corporation, Haldia Petrochemicals Limited, OPAL, HMEL, BCPL, etc. Homo and copolymerization of propylene is one of the most important process catalyzed by transition metal complexes. These catalyst system was first discovered by Ziegler and Natta in 1950’s. K. Ziegler and G. Natta were given The Noble Prize for this discovery in 1963. Since then, PROF ROBERT H many inventions and innovations in Ziegler – Natta GRUBBS catalysts transformed polyolefin industry to become one of the largest among polymer industries. Notable efforts are focused to improve the activity and selectivity of catalysts for propylene polymerization by employing synthetic, analytical, and computational tools for understanding at the molecular levels. Gupta, Grubbs et al. developed a series of novel hybrid catalysts (Figure-1) based on metallocene & titanium complexes supported over magnesium dichloride support (4,5). These catalysts in combination with alkyl aluminum/ aluminoxane showed unique capability to produce high performance polypropylene copolymers with high contribution of ethylene-propylene rubber critical for applications in fast growing automobile sectors. Another class of novel catalyst systems also developed (6) modified with unique Lewis base to alter the FIGURE-1 HYBRID CATALYST

kinetics of propylene polymerization. This feature is essential for designing high production polymerization process, particularly in gas phase. DFT ( Density Functional Theory) studies (7) of the developed catalyst reveal that chemical interactions of Lewis base with Lewis acid such as alkyl aluminum and titanium complex attached on the specific surface of magnesium dichloride led to chemical reactions to generate products influencing the kinetics of polymerization. Further, steric, and electronic factors of Lewis base plays a significant role in controlling different pathways of chemical transformation. These DFT studies agree with experimental observation of developed novel catalyst system. It opens new opportunities for developing high performance catalysts for different grades of polypropylene for emerging new product applications in growth sectors.

REFERENCES:

1. Parthiv Trivedi, Virendra Kumar Gupta, Journal of Polymer Research, 28, 1-20, 2021. 2. J. Kumawat, Virendra Kumar Gupta, Polymer Chemistry, 11, 61076128, 2020. 3. Global polypropylene market volume 2015-2026; Published by Ian Tiseo, Oct19, 2021. 4. Virendra kumar Gupta, Robert H. Grubbs., Subbarayan Velusamy, Sanket Shah, Aadesh Sharma, Ajay Kothari; Supported hybrid metallocene catalyst system and process for homo- polymerization and co-polymerization of olefins; Indian Patent Application 4199/ MUM/2015. 5. Virendra kumar Gupta, Subbarayan Velusamy, Sanket Shah, Aadesh Sharma, Robert H. Grubbs; A supported hybrid metallocene catalyst for olefin polymerization and a process for preparation thereof; Indian Patent Application 4278/MUM/2015. 6. Virendra kumar Gupta; Robert H. Grubbs, Sunil Dhamaniya; A ZieglerNatta catalyst system with self-extinguishing properties suitable for olefin polymerization; US Patents Publication No. US 2021/0024662A1, Jan 28, 2021; PCT Int. Publication WO 2019/155393 A1, Aug 15, 2019; Indian Patent Application IN 201821004697 A, Feb 07, 2018; Indonesia Application No. P00202005885, Aug 12, 2020; South Korea Patent Application No. KR20200135776A, Dec03, 2020. 7. K. Vipin Raj, Jugal Kumawat, Sunil Dhamaniya, Murugan Subaramanian, Ekambaram Balaraman, Virendra Kumar Gupta, Kumar Vanka, Robert H. Grubbs; Insights into the Nature of Self-Extinguishing External Donors for Ziegler-Natta Catalysis: A Combined Experimental and DFT Study; ChemCatChem 13(2), 674-681, 2021.

ABOUT THE AUTHOR: DR VIRENDRA K GUPTA, Distinguished Visiting Professor, Somaiya Vidyavihar University & Senior Vice President, Reliance Industries Limited is an accomplished Scientist who has successfully translated his fundamental work done in Material Science into Commercial Technologies and implemented first time in India. He is Fellow of The National Academy of Sciences, India (NASI) and a recipient of VASVIK Award, Acharya PC Ray Awards for Development of Indigenous Technology and 25 Other Technology and Product Development Awards from Govt of India and Industrial Organizations. Dr Gupta is an inventor / coinventor of 200 patents and published 80 Research Papers in Peer reviewed Journals. Dr Gupta obtained Ph.D. from Banaras Hindu University and worked also at Indian Petrochemicals Corporation Limited, Gharda Chemicals Limited and University of Alabama at Birmingham, USA.