Synthesis of highly reactive polyisobutylene catalyzed by EtAlCl 2/Bis(2-chloroethyl) ether soluble complex in hexanes

Handle URI:
http://hdl.handle.net/10754/563455
Title:
Synthesis of highly reactive polyisobutylene catalyzed by EtAlCl 2/Bis(2-chloroethyl) ether soluble complex in hexanes
Authors:
Kumar, Rajeev Ananda; Zheng, Bin; Huang, Kuo-Wei ( 0000-0003-1900-2658 ) ; Emert, Jack I.; Faust, Rudolf
Abstract:
The polymerization of isobutylene (IB) to yield highly reactive polyisobutylene (HR PIB) with high exo-olefin content using GaCl3 or FeCl3·diisopropyl ether complexes has been previously reported.1 In an effort to further improve polymerization rates and exo-olefin content, we have studied ethylaluminum dichloride (EADC) complexes with diisopropyl ether, 2-chloroethyl ethyl ether (CEEE), and bis(2-chloroethyl) ether (CEE) as catalysts in conjunction with tert-butyl chloride as initiator in hexanes at different temperatures. All three complexes were readily soluble in hexanes. Polymerization, however, was only observed with CEE. At 0 °C polymerization was complete in 5 min at [t-BuCl] = [EADC·CEE] = 10 mM and resulted in PIB with ∼70% exo-olefin content. Studies on complexation using ATR FTIR and 1H NMR spectroscopy revealed that at 1:1 stoichiometry a small amount of EADC remains uncomplexed. By employing an excess of CEE, exo-olefin contents increased up to 90%, while polymerization rates decreased only slightly. With decreasing temperature, polymerization rates decreased while molecular weights as well as exo-olefin contents increased, suggesting that isomerization has a higher activation energy than β-proton abstraction. Density functional theory (DFT) studies on the Lewis acid·ether binding energies indicated a trend consistent with the polymerization results. The polymerization mechanism proposed previously for Lewis acid·ether complexes1 adequately explains all the findings. © 2014 American Chemical Society.
KAUST Department:
KAUST Catalysis Center (KCC); Physical Sciences and Engineering (PSE) Division; Chemical Science Program; HCL
Publisher:
American Chemical Society (ACS)
Journal:
Macromolecules
Issue Date:
25-Mar-2014
DOI:
10.1021/ma500042f
Type:
Article
ISSN:
00249297
Sponsors:
Financial support from Infineum USA is greatly appreciated.
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; Chemical Science Program; KAUST Catalysis Center (KCC)

Full metadata record

DC FieldValue Language
dc.contributor.authorKumar, Rajeev Anandaen
dc.contributor.authorZheng, Binen
dc.contributor.authorHuang, Kuo-Weien
dc.contributor.authorEmert, Jack I.en
dc.contributor.authorFaust, Rudolfen
dc.date.accessioned2015-08-03T11:51:56Zen
dc.date.available2015-08-03T11:51:56Zen
dc.date.issued2014-03-25en
dc.identifier.issn00249297en
dc.identifier.doi10.1021/ma500042fen
dc.identifier.urihttp://hdl.handle.net/10754/563455en
dc.description.abstractThe polymerization of isobutylene (IB) to yield highly reactive polyisobutylene (HR PIB) with high exo-olefin content using GaCl3 or FeCl3·diisopropyl ether complexes has been previously reported.1 In an effort to further improve polymerization rates and exo-olefin content, we have studied ethylaluminum dichloride (EADC) complexes with diisopropyl ether, 2-chloroethyl ethyl ether (CEEE), and bis(2-chloroethyl) ether (CEE) as catalysts in conjunction with tert-butyl chloride as initiator in hexanes at different temperatures. All three complexes were readily soluble in hexanes. Polymerization, however, was only observed with CEE. At 0 °C polymerization was complete in 5 min at [t-BuCl] = [EADC·CEE] = 10 mM and resulted in PIB with ∼70% exo-olefin content. Studies on complexation using ATR FTIR and 1H NMR spectroscopy revealed that at 1:1 stoichiometry a small amount of EADC remains uncomplexed. By employing an excess of CEE, exo-olefin contents increased up to 90%, while polymerization rates decreased only slightly. With decreasing temperature, polymerization rates decreased while molecular weights as well as exo-olefin contents increased, suggesting that isomerization has a higher activation energy than β-proton abstraction. Density functional theory (DFT) studies on the Lewis acid·ether binding energies indicated a trend consistent with the polymerization results. The polymerization mechanism proposed previously for Lewis acid·ether complexes1 adequately explains all the findings. © 2014 American Chemical Society.en
dc.description.sponsorshipFinancial support from Infineum USA is greatly appreciated.en
dc.publisherAmerican Chemical Society (ACS)en
dc.titleSynthesis of highly reactive polyisobutylene catalyzed by EtAlCl 2/Bis(2-chloroethyl) ether soluble complex in hexanesen
dc.typeArticleen
dc.contributor.departmentKAUST Catalysis Center (KCC)en
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.contributor.departmentChemical Science Programen
dc.contributor.departmentHCLen
dc.identifier.journalMacromoleculesen
dc.contributor.institutionPolymer Science Program, Department of Chemistry, University of Massachusetts Lowell, One University Avenue, Lowell, MA 01854, United Statesen
dc.contributor.institutionInfineum USA, 1900 E. Linden Avenue, Linden, NJ 07036, United Statesen
kaust.authorZheng, Binen
kaust.authorHuang, Kuo-Weien
All Items in KAUST are protected by copyright, with all rights reserved, unless otherwise indicated.