Rationalizing chain microstructure in the poly[alpha]-olefins synthesized by cationic AlCl3/H2O catalytic system

In this study, three middle range α-olefin monomers including 1-hexene, 1-octene, and 1-decene were oligomerized using conventional AlCl3/H2O catalytic system. Molecular weight and microstructure of the oligomers were analyzed by GPC and 1HNMR, respectively. By 1HNMR spectra, both internal (CHR=CHR[...

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Bibliographic Details
Published inInternational journal of polymer analysis & characterization Vol. 24; no. 6; p. 556
Main Authors Sadjadi, Samaheh, Bahri-Laleh, Naeimeh, Nekoomanesh-Haghighi, Mehdi, Ziaee, Farshid, Dehghani, Sedva, Shirbakht, Sedigheh, Rahbar, Ameneh, Barough, Mehdi Salehi, Mirmohammadi, Seyed Amin
Format Journal Article
LanguageEnglish
Published Philadelphia Taylor & Francis Ltd 01.01.2019
Subjects
Alkenes
Aluminum chloride
Catalysis
Chemical synthesis
Hydrogenation
Isomerization
Microstructure
Molecular weight
Monomers
Oligomerization
Oligomers
Spectrum analysis
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Summary:In this study, three middle range α-olefin monomers including 1-hexene, 1-octene, and 1-decene were oligomerized using conventional AlCl3/H2O catalytic system. Molecular weight and microstructure of the oligomers were analyzed by GPC and 1HNMR, respectively. By 1HNMR spectra, both internal (CHR=CHR[vprime] and CHR=CR[vprime]R[vprime][vprime]) and external (CH2=CR[vprime]R[vprime][vprime]) olefins containing di and tri-substituted C=C bonds were detected. After successful oligomerization, synthesized polyα-olefins underwent hydrogenation process using Pd(0)-Hal catalyst to yield synthetic oils of PHex, POct, and PDec, respectively and then completion of the hydrogenation was confirmed by 1HNMR spectroscopy. The microstructure of the synthesized oligomers was rationalized using the ratio under the peak of CH + CH2/CH3 hydrogens (S1/S2) in 1HNMR spectra and the degree of oligomerization obtained from Mn. According to the results, the best match between theoretical and real S1/S2 is obtained when considering double bond isomerization in the synthesized PAOs. By knowing PAO molecular weight, a relationship between monomer type and S1/S2 in the PAO homopolymers was detected. Our suggested methodology can be generalized to the unknown PAO homopolymers to unravel their monomer type by simple 1HNMR and GPC analyses.
ISSN:1023-666X
1563-5341
DOI:10.1080/1023666X.2019.1627027