Thermally induced polymerization of isobutylene in the presence of SnCl4: Kinetic study of the polymerization and NMR structural investigation of low molecular weight products

Toman, Ludék; Spěváček, Jiří; Vlček, Petr; Holler, Petr

doi:10.1002/(sici)1099-0518(20000501)38:9<1568::aid-pola21>3.0.co;2-p

Cited by 20 publications

(15 citation statements)

References 35 publications

(64 reference statements)

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“…These two structures of F 1 and F 2 are very similar and differ only by a shift of the double bond of one monomer unit inside the polymer chain. A weak singlet peak at δ = 5.12 was attributed to the proton in C(CH 3 ) C H C(CH 3 ) 2 (sructure D ) . These 1 H NMR results are similar to those of HRPIBs obtained with H 2 O/AlCl 3 /dialkyl ether and H 2 O/FeCl 3 /dialkyl ether initiating systems .…”

Section: Resultssupporting

confidence: 75%

Synthesis of highly reactive polyisobutylenes with exo-olefin terminals via controlled cationic polymerization with H₂O/FeCl₃/iPrOH initiating system in nonpolar hydrocarbon media

Guo

Yang

Yan

et al. 2013

J. Polym. Sci. Part A: Polym. Chem.

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Cationic polymerizations of isobutylene (IB) with H 2 O/FeCl 3 /isopropanol (iPrOH) initiating system were conducted in nonpolar hydrocarbon media, such as n-hexane or mixed C 4 fractions at 240 to 20C. This cationic polymerization is a chain-transfer dominated process via highly selective bproton elimination from ACH 3 in the growing chain ends, leading to formation of highly reactive polyisobutylenes (HRPIBs) with large contents (> 90 mol %) of exo-olefin end groups (structure A). The content of structure A remained nearly constant at about 97 mol % during polymerization and isomerization via carbenium ion rearrangement could be suppressed in nonpolar media. First-order kinetics with respect to monomer concentration was measured for selective cationic polymerization of IB in the mixed C 4 fraction feed at 230 C and the apparent rate constant for propagation was 0.028 min 21 .High polymerization temperature (T p ) or [FeCl 3 ] accelerate b-proton elimination or isomerizations and simultaneously decrease selectivity of b-proton abstraction from ACH 3 . Molecular weight decreased and molecular weight distribution (MWD) became narrow with increasing T p or [FeCl 3 ]. To the best of our knowledge, this is the first example to achieve high quality HRPIBs with near 100% of exo-olefin terminals and relatively narrow MWD (M w /M n 5 1.8) by a single-step process in nonpolar hydrocarbon media. PIBs with >70 mol % of exo-olefin end groups (ACH 2 AC(CH 3 )@CH 2 , structure A), preferably more than 80 mol %, are normally referred to as highly reactive polyisobutylenes (HRPIBs). HRPIBs, differing from those conventional PIBs with <10% of exo-olefin end groups, have found applications as intermediates in the preparation of additives for fuels and lubricants or other further functional modification since only terminal exo-olefin in PIB chain has a sufficiently high reactivity.3,4 HRPIBs can efficiently react with maleic anhydride by direct addition reaction to synthesize PIB/maleic anhydride adducts. The high content of exo-olefin end groups and relatively narrow molecular weight distributions (MWDs) are the most important quality criteria for HRPIBs.

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Section: Resultssupporting

confidence: 75%

Synthesis of highly reactive polyisobutylenes with exo-olefin terminals via controlled cationic polymerization with H₂O/FeCl₃/iPrOH initiating system in nonpolar hydrocarbon media

Guo

Yang

Yan

et al. 2013

J. Polym. Sci. Part A: Polym. Chem.

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“…A possible source of this discrepancy could be the fact that the low‐molecular‐weight fractions of PIB(NCO) n are soluble in acetone, from which the PIB(NCO) n was isolated (see Experimental section). The M w / M n value of PIB(MA) n is comparable with those of commercial PIBs, such as Oppanol B3 ( M w / M n = 3.5) 28…”

Section: Resultsmentioning

confidence: 58%

“…A slightly higher intensity of signal d can be due to the fact that also methylene protons from C H 2 C(CH 3 ) 2 Cl and C H 2 C(CH 3 )CH 2 polyisobutylene terminal groups25 as well as methyl protons from C(C H 3 )CH 2 methacrylate terminal groups contribute to this signal. Figure 3 also shows resonances in the region 4.6–5.2 ppm, the range typical of unsaturated terminal groups of PIB,25, 28, 30, 31 where endo type CHC(CH 3 ) 2 (signal e) generally prevails over exo types 10. The resonance of methyl protons from C(C H 3 ) 3 PIB head‐groups10, 25, 32 (signal f) can be also found in the spectrum.…”

Section: Resultsmentioning

confidence: 99%

One‐pot synthesis of isocyanate and methacrylate multifunctionalized polyisobutylene and polyisobutylene‐based amphiphilic networks

Toman

Janata

Spěváček

et al. 2006

J. Polym. Sci. A Polym. Chem.

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Amphiphilic polymer networks consisting of hydrophilic poly(2-hydroxyethyl methacrylate) (PHEMA) and hydrophobic polyisobutylene (PIB) chains were synthesized from a cationic copolymer of isobutylene (IB) and 3-isopropenyl-a,a-dimethylbenzyl isocyanate (IDI) prepared at À50 8C in dichloromethane in conjunction with SnCl 4 . The isocyanate groups of this random copolymer, PIB(NCO) n , were subsequently transformed in situ to methacrylate (MA) groups in the dibutyltin dilauratecatalyzed reaction with 2-hydroxyethyl methacrylate (HEMA) at 30 8C. The resulting PIB(MA) n with number-average molecular weight 8200 and average functionality F n $ 4 per chain was in situ copolymerized radically with HEMA at 70 8C, giving rise to the amphiphilic networks containing 41 and 67 mol % HEMA. PHEMA-PIB network containing 43 mol % HEMA was also prepared by radical copolymerization of PIB (MA) n precursor with HEMA using sequential synthesis. An amphiphilic nature of the resulting networks was proved by swelling in both water and n-heptane. PIB(NCO) n and PIB(MA) n were characterized by FTIR spectroscopy, SEC and the latter also by 1 H NMR spectroscopy. Solid state 13 C NMR spectroscopy was used for characterization of the resulting PHEMA-PIB networks. Whereas single glass-transition temperature, T g ¼ À67.4 8C, was observed for the rubbery crosslinked PIB prepared by reaction of PIB(NCO) n with water, the PHEMA-PIB networks containing 67 and 41 mol % HEMA showed two T g 's: À70.4 and 102.7 8C, and À63 and 107.2 8C, respectively.

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“…In the 1 H NMR spectra of PIBs (see samples 2 and 3 in Fig. 8), no resonances from 4.6 to 5.2 ppm, the range typical of unsaturated end groups of PIB,39, 43, 45–48 were detected. Moreover, no signals in the aromatic region (6.3–7.2 ppm)38 were found for these PIBs, and this confirmed that in the Soxhlet extraction, no copolymer was transferred into the PIB phase.…”

Section: Resultsmentioning

confidence: 97%

Sequential synthesis of multiblock copolymers by atom transfer radical and cationic polymerization

Toman

Janata

Spěváček

et al. 2004

J. Polym. Sci. A Polym. Chem.

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ABCBA-type pentablock copolymers of methyl methacrylate (MMA), styrene (S), and isobutylene (IB) were prepared by a three-step synthesis, which included atom transfer radical polymerization (ATRP) and cationic polymerization: (1) poly-(methyl methacrylate) (PMMA) with terminal chlorine atoms was prepared by ATRP initiated with an aromatic difunctional initiator bearing two trichloromethyl groups under CuCl/2,2Ј-bipyridine catalysis; (2) PMMA with the same catalyst was used for ATRP of styrene, which produced a poly(S-b-MMA-b-S) triblock copolymer; and (3) IB was polymerized cationically in the presence of the aforementioned triblock copolymer and BCl 3 , and this produced a poly(IB-b-S-b-MMA-b-S-b-IB) pentablock copolymer. The reaction temperature, varied from Ϫ78 to Ϫ25°C, significantly affected the IB content in the product; the highest was obtained at Ϫ25°C. The formation of a pentablock copolymer with a narrow molecular weight distribution provided direct evidence of the presence of active chlorine at the ends of the poly(S-b-MMA-b-S) triblock copolymer, capable of the initiation of the cationic polymerization of IB in the presence of BCl 3 . A differential scanning calorimetry trace of the pentablock copolymer (20.1 mol % IB) showed the glass-transition temperatures of three segregated domains, that is, polyisobutylene (Ϫ87.4°C), polystyrene (95.6°C), and PMMA (103.7°C) blocks. One glass-transition temperature (104.5°C) was observed for the aforementioned triblock copolymer.

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Thermally induced polymerization of isobutylene in the presence of SnCl4: Kinetic study of the polymerization and NMR structural investigation of low molecular weight products

Cited by 20 publications

References 35 publications

Synthesis of highly reactive polyisobutylenes with exo-olefin terminals via controlled cationic polymerization with H₂O/FeCl₃/iPrOH initiating system in nonpolar hydrocarbon media

Synthesis of highly reactive polyisobutylenes with exo-olefin terminals via controlled cationic polymerization with H₂O/FeCl₃/iPrOH initiating system in nonpolar hydrocarbon media

One‐pot synthesis of isocyanate and methacrylate multifunctionalized polyisobutylene and polyisobutylene‐based amphiphilic networks

Sequential synthesis of multiblock copolymers by atom transfer radical and cationic polymerization

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Thermally induced polymerization of isobutylene in the presence of SnCl4: Kinetic study of the polymerization and NMR structural investigation of low molecular weight products

Cited by 20 publications

References 35 publications

Synthesis of highly reactive polyisobutylenes with exo-olefin terminals via controlled cationic polymerization with H2O/FeCl3/iPrOH initiating system in nonpolar hydrocarbon media

Synthesis of highly reactive polyisobutylenes with exo-olefin terminals via controlled cationic polymerization with H2O/FeCl3/iPrOH initiating system in nonpolar hydrocarbon media

One‐pot synthesis of isocyanate and methacrylate multifunctionalized polyisobutylene and polyisobutylene‐based amphiphilic networks

Sequential synthesis of multiblock copolymers by atom transfer radical and cationic polymerization

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Product

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Synthesis of highly reactive polyisobutylenes with exo-olefin terminals via controlled cationic polymerization with H₂O/FeCl₃/iPrOH initiating system in nonpolar hydrocarbon media

Synthesis of highly reactive polyisobutylenes with exo-olefin terminals via controlled cationic polymerization with H₂O/FeCl₃/iPrOH initiating system in nonpolar hydrocarbon media