Double-bond isomerization of hexadecenes with solid acid catalysts

Bruno, James E.; Dooley, Kerry M.

doi:10.1016/j.apcata.2015.03.009

Cited by 15 publications

(8 citation statements)

References 46 publications

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“…Reactions such as oligomerization, alkylation, and cracking compete with isomerization, and the reaction selectivity is said to depend on the reaction temperature and strength of acid sites on the catalyst surface. ,,,, For example, oligomerization is slow on weak acid sites and is favored at higher temperatures compared to isomerization reactions. , On the other hand, it was found in the literature that double bond migration could still occur on a higher number of weak acid sites. ,, …”

Section: Discussionmentioning

confidence: 99%

Free Radical and Cationic Addition due to Clay Minerals Found in Bitumen Froth at 250 °C Probed with Use of α-Methylstyrene and 1-Octene

Turuga

Klerk

2022

Energy Fuels

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Following previous evidence that hydrothermal treatment of bitumen froth does not lead to bitumen upgrading at 250 °C and promotes viscosity increase, the current study explores the free radical and cationic reactivity of clay minerals found in bitumen froth in promoting heavier material formation through addition reactions. The current investigation employed α-methylstyrene (AMS) and 1-octene as probe molecules instead of bitumen froth, and their conversion at 250 °C in the presence of clay minerals kaolinite and illite was studied in batch reactors. Thermal conversion of AMS and 1-octene at 250 °C in the absence of minerals was observed to be low. In the presence of clay minerals, not only the conversion of AMS and 1-octene was increased but also reactions such as dimerization of AMS and alkylation of 1-octene and toluene (used as solvents) were mainly promoted, leading to heavier product formation. Double-bond isomerization of 1-octene and cumene formation from AMS was side reactions that were also promoted by the clay minerals. Suppression of mineral-related conversion by pyridine and selectivity to different reaction products that enabled differentiation between free radical and cationic reaction pathways indicated that the mineral-related conversion was predominantly cationic in nature. Using the reactions in the presence of minerals and pyridine as surrogates for alkaline bitumen froth, it was concluded that even under alkaline conditions, minerals could promote heavier material formation through cationic addition.

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Section: Discussionmentioning

confidence: 99%

Free Radical and Cationic Addition due to Clay Minerals Found in Bitumen Froth at 250 °C Probed with Use of α-Methylstyrene and 1-Octene

Turuga

Klerk

2022

Energy Fuels

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“…The decrease of the Al/Zr ratio from 20 to 10 led to a decrease in activity and to a significant increase in the chain length of oligomers (entry 12, Table 3; Figure 5b). At the same time, selectivity to LAO increased to 97% as a result of the decrease in the number of aluminum acid centers which are active in olefin isomerization [51,52]. In turn, the increase of the Al/Zr ratio from 20 to 40 resulted in the shortening of oligomers (α decreased to 0.45) and decrease in activity to 7.6 × 10 3 mol C2H4 ·mol Zr −1 ·h −1 (entry 13, Table 3).…”

Section: Ethylene Oligomerizationmentioning

confidence: 99%

Electrochemical Synthesis of Zirconium Pre-Catalysts for Homogeneous Ethylene Oligomerization

et al. 2019

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The catalytic activity of electrochemically synthesized zirconium carboxylates was studied in the process of ethylene oligomerization. Zirconium carboxylates were electrochemically synthesized directly from metallic zirconium and corresponding carboxylic acids (acetic, octanoic and lauric). A comprehensive study (element analysis, nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy, powder X-ray diffraction (PXRD)) of the synthesized zirconium carboxylates showed that these species contain bidentate carboxylate moieties. It was shown that obtained zirconium carboxylates, in combination with Et 3 Al 2 Cl 3 (Al/Zr = 20), have a moderate activity of (7.6-9.9) × 10 3 mol C2H4 ·mol Zr −1 ·h −1 in terms of ethylene oligomerization (at T = 80 • C, p = 20 bar), leading to even-numbered C 4 -C 10 linear alpha-olefins.

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“…When a linear alkene is the only reactant treated with dry Amberlyst®15 catalyst or other solid acids, dimerization of the alkene occurs alongside double bond isomerization. [ 4–12 ] We have recently investigated the kinetics of concurrent dimerization and double bond isomerization of linear 1‐alkenes on Amberlyst®15 catalyst, and we present here evidence that double bond isomerization occurs on a site where dimerization does not occur. Adsorption coefficients for linear alkenes on the isomerization sites are small (i.e., ≤0.01), whereas the adsorption coefficients for linear alkenes on the dimerization sites are large (i.e., ≥10).…”

Section: Introductionmentioning

confidence: 86%

Not all acid sites are created equal: Alkene isomerization and dimerization occur on separate sites on Amberlyst®15 catalyst

Gee

2020

J of Physical Organic Chem

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Linear 1‐alkenes undergo concurrent dimerization and double bond isomerization on the solid acid catalyst Amberlyst®15. Kinetic data show that double bond isomerization occurs on a site where the alkene adsorption coefficient is small, whereas alkene dimerization occurs on a site where the alkene adsorption coefficient is large. The fraction of isomerization sites occupied by alkene is small, whereas the dimerization sites are practically saturated with alkene. Logically, two different types of acid sites must exist on the surface of Amberlyst®15 catalyst. On the dimerization sites, substantial skeletal rearrangement occurs, likely via rapidly isomerizing carbenium ions, π‐complexes, and/or protonated cyclopropyl intermediates.

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Double-bond isomerization of hexadecenes with solid acid catalysts

Cited by 15 publications

References 46 publications

Free Radical and Cationic Addition due to Clay Minerals Found in Bitumen Froth at 250 °C Probed with Use of α-Methylstyrene and 1-Octene

Free Radical and Cationic Addition due to Clay Minerals Found in Bitumen Froth at 250 °C Probed with Use of α-Methylstyrene and 1-Octene

Electrochemical Synthesis of Zirconium Pre-Catalysts for Homogeneous Ethylene Oligomerization

Not all acid sites are created equal: Alkene isomerization and dimerization occur on separate sites on Amberlyst®15 catalyst

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