A study of intermolecular hydrogen transfer from naphthenes to 1-hexene over zeolite catalysts

Потапенко, О. В.; Доронин, В. П.; Сорокина, Т. П.; Krol, O. V.; Likholobov, V. A.

doi:10.1016/j.apcata.2016.02.028

Cited by 20 publications

(5 citation statements)

References 23 publications

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“…For the gaseous fraction, increasing the proportion of sunflower oil in the feed increased the yields of C 3 and C 4 paraffins but decreased those of C 3 and C 4 olefins. Figure 3(a) also presents the C 4 paraffin/C 4 olefin ratio, which is an index of hydrogen-transfer activity during hydrocarbon cracking: a high C 4 paraffin/C 4 olefin ratio in the reaction products indicates a significant hydrogen-transfer reaction (Potapenko et al, 2016). The C 4 paraffin/C 4 olefin ratio remained largely constant and near unity for small sunflower oil fractions (<20 wt%), but increased drastically for larger sunflower oil fractions.…”

Section: Co-processing Of Coconut Oil and Sun Ower Oilmentioning

confidence: 99%

Co-processing of Saturated and Unsaturated Triglycerides in Catalytic Cracking Process for Hydrocarbon Fuel Production

Shimada

Nakamura

Ohta³

et al. 2018

J. Chem. Eng. Japan / JCEJ

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With the aim of the e cient use of plant oils as alternative fuels, the deoxygenation of saturated and unsaturated triglycerides in a catalytic cracking process was investigated using a uid catalytic cracking catalyst with enhanced hydrogentransfer activity. The decomposition and deoxygenation of sun ower oil (unsaturated triglycerides) proceeded rapidly and produced a large amount of aromatic hydrocarbons, which are unsuitable for fuel applications. In contrast, the rate of deoxygenation of coconut oil (saturated triglycerides) was slow and some oxygen-containing species were observed as products. During the co-processing of saturated and unsaturated triglycerides, the deoxygenation of saturated triglycerides was accelerated and complete deoxygenation was achieved. The acceleration of the deoxygenation reaction was attributed to the rapid formation of hydrogen donors, such as ole ns and naphthenes, from the decomposition of unsaturated triglycerides. The ole ns and naphthenes released hydrogen species by cyclization and aromatization reactions. These hydrogen species then reacted with saturated triglycerides and their derivatives (fatty acids and aldehydes) in hydrogen-transfer reactions, accelerating the hydrodeoxygenation of saturated triglycerides. The hydrodeoxygenation of saturated triglycerides produced para ns and ole ns rather than aromatics. The increase in the amount of para ns and ole ns produced by the accelerated deoxygenation of saturated triglycerides was larger than the amount of aromatic hydrocarbons derived from unsaturated triglycerides. Thus, co-processing of saturated and unsaturated triglycerides was con rmed to be e ective for simultaneously achieving both the acceleration of saturated triglyceride deoxygenation and the suppression of aromatic hydrocarbon formation.

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Section: Co-processing Of Coconut Oil and Sun Ower Oilmentioning

confidence: 99%

Co-processing of Saturated and Unsaturated Triglycerides in Catalytic Cracking Process for Hydrocarbon Fuel Production

Shimada

Nakamura

Ohta³

et al. 2018

J. Chem. Eng. Japan / JCEJ

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“…The butane/butene ratio is used as an index representing the hydrogen transfer activities of the different catalysts. A higher butane/butene ratio indicates higher hydrogen transfer activity because the hydrogen transfer reaction converts olefins to paraffins, and because the proportions of unsaturated and saturated hydrocarbons in gasoline obtained from cracking reactions corresponds to that in the C 4 fraction. − The results shown in Figure a therefore suggest that the yield of oxygenates decreases with increasing hydrogen transfer activity.…”

Section: Results and Discussionmentioning

confidence: 99%

Deoxygenation of Triglycerides by Catalytic Cracking with Enhanced Hydrogen Transfer Activity

Shimada

Kato

Hirazawa

et al. 2016

Ind. Eng. Chem. Res.

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The efficient use of plant oils as alternative fuels was investigated by studying triglyceride deoxygenation in catalytic cracking using a fluid catalytic cracking catalyst with enhanced hydrogen transfer activity. Unsaturated triglyceride deoxygenation was rapid and complete, but small amounts of oxygenated products such as fatty acids, ketones, and aldehydes were produced from saturated triglycerides. Reaction product analysis showed that hydrogen transfer reactions between oxygenates and hydrocarbons produced by cracking fatty acid carbon chains caused hydrodeoxygenation even in the absence of hydrogen. Catalytic cracking of triglycerides with fatty acid carbon chains of various lengths showed that triglyceride deoxygenation is not affected by steric hindrance, and probably occurs on zeolite external surfaces, whereas secondary cracking of hydrocarbons occurs on the internal surfaces. We showed that catalytic cracking can be used for efficient conversion of triglycerides to hydrocarbons in the absence of hydrogen.

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“…On the other hand, the precursor HZSM-12 zeolite exhibited the highest yield to light olefins due to its higher proportion of strong acid sites and exclusively microporous structure. As is well-known, the shape selectivity properties of the conventional HZSM-12 zeolites inhibit the occurrence of bimolecular reactions inside of its exclusively 1D/12MR microporous system, such as hydrogen transfer reactions, which lead to the formation of paraffins …”

Section: Resultsmentioning

confidence: 99%

“…As is well-known, the shape selectivity properties of the conventional HZSM-12 zeolites inhibit the occurrence of bimolecular reactions inside of its exclusively 1D/12MR microporous system, such as hydrogen transfer reactions, which lead to the formation of paraffins. 50 In summary, the presence of intracrystalline mesopores in HZSM-12 zeolites leads to an increase in the ratio of the rates of ring contraction and ring opening. The obtained yield distribution and selectivity to products (Figure 7 and SI, Table S1) are consistent with the reaction mechanism of cyclohexane transformation on microporous 12MR-H-zeolites.…”

Section: Industrial and Engineering Chemistry Researchmentioning

confidence: 92%

Generation of 3D-Intracrystalline Diffusion Structures from a 1D/12MR HZSM-12 Zeolite: Improvements in the Catalytic Stability

Carvalho

Silva

Urquieta‐González

2019

Ind. Eng. Chem. Res.

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Three-dimensional-intracrystalline diffusion structures were prepared from a 1D/12MR-HZSM-12 zeolite that was desilicated with NaOH solutions at different temperatures. The results showed that carefully tuned desilication preserved most of the crystalline structure and revealed that even though the strong acid sites had decreased, the hierarchical zeolites exhibited similar initial activities compared to that of the 1D-microporous precursor. Moreover, the new textural and acid properties of the desilicated zeolites strongly improved the catalytic stability during cyclohexane conversion. That stability, a key factor to be considered in the engineering scale-up of the catalyst, resulted from the decrease of the strong acid sites and more importantly from improvements in the molecular diffusion inside of the new 3D-intracrystalline porous structure that decreased the contact time, minimizing subsequent reactions that could lead to coke formation, thus avoiding deactivation. Otherwise, the presence of mesopores favored the selectivity to C6 cyclohexane isomers.

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A study of intermolecular hydrogen transfer from naphthenes to 1-hexene over zeolite catalysts

Cited by 20 publications

References 23 publications

Co-processing of Saturated and Unsaturated Triglycerides in Catalytic Cracking Process for Hydrocarbon Fuel Production

Co-processing of Saturated and Unsaturated Triglycerides in Catalytic Cracking Process for Hydrocarbon Fuel Production

Deoxygenation of Triglycerides by Catalytic Cracking with Enhanced Hydrogen Transfer Activity

Generation of 3D-Intracrystalline Diffusion Structures from a 1D/12MR HZSM-12 Zeolite: Improvements in the Catalytic Stability

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