Rate of Formation of Industrial Lubricant Additive Precursors from Maleic Anhydride and Polyisobutylene

Streets, Jessica; Proust, Nicolas; Parmar, Dixit; Walker, Gary; Licence, Peter; Woodward, Simon

Abstract

The Alder-ene reaction of neat polyisobutylene (PIB) and maleic anhydride (MAA) to produce the industrially important lubricant additive precursor polyisobutylene succinic anhydride (PIBSA) is studied at 150-180 °C. Under anaerobic conditions with [PIB] ∼1.24 M (550 g mol-1 grade, >80% exo alkene) and [MAA] ∼1.75 M, conversion of exo-PIB and MAA follows second-order near-equal rate laws with kobs up to 5 × 10-5 M-1 s-1 for both components. The exo-alkene-derived primary product PIBSA-I is formed at an equivalent rate. The less reactive olefinic protons of exo-PIB also react with MAA to form isomeric PIBSA-II (kobs up to 6 × 10-5 M-1 s-1). Some exo-PIB is converted to endo-PIB (containing trisubstituted alkene) in a first-order process (kobs ∼1 × 10-5 s-1), while PIBSA-I is difunctionalized by MAA to bis-PIBSAs very slowly. The MAA- and PIB-derived activation parameter ΔG‡(150 °C) 34.3 ± 0.3 kcal mol-1 supports a concerted process, with that of PIBSA-I suggesting a late (product-like) transition state.

Citation

Streets, J., Proust, N., Parmar, D., Walker, G., Licence, P., & Woodward, S. (2022). Rate of Formation of Industrial Lubricant Additive Precursors from Maleic Anhydride and Polyisobutylene. Organic Process Research and Development, 26(9), 2749-2755. https://doi.org/10.1021/acs.oprd.2c00207

• Journal Article Type: Article
• Acceptance Date: Aug 12, 2022
• Online Publication Date: Aug 30, 2022
• Publication Date: Aug 30, 2022
• Deposit Date: Sep 12, 2022
• Publicly Available Date: Sep 12, 2022
• Journal: Organic Process Research and Development
• Print ISSN: 1083-6160
• Electronic ISSN: 1520-586X
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 26
• Issue: 9
• Pages: 2749-2755
• DOI: https://doi.org/10.1021/acs.oprd.2c00207
• Keywords: Article, kinetics, ene reaction, thermal, mechanism, energetics, lubricant
• Public URL: https://nottingham-repository.worktribe.com/output/10638872
• Publisher URL: https://pubs.acs.org/doi/10.1021/acs.oprd.2c00207