Kinetic scheme of homogeneous acid-catalyzed transformation of isopentenols

Ryabova, R. S.; Osipova, G. F.; Travin, S. O.

doi:10.1007/bf00696913

Cited by 2 publications

(4 citation statements)

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“…This acid-catalyzed reaction is traditionally catalyzed by homogeneous mineral acids, Lewis acids like SnCl 4 , as well as solid Lewis acid catalysts. Our findings are also consistent with those of Travin and co-workers, who report a reverse Prins reaction of 3-methyl-2-buten-1-ol to form isobutylene and formaldehyde over H 2 SO 4 catalyst …”

Section: Resultsmentioning

confidence: 99%

“…Our findings are also consistent with those of Travin and co-workers, who report a reverse Prins reaction of 3-methyl-2-buten-1-ol to form isobutylene and formaldehyde over H 2 SO 4 catalyst. 28 The changes in carbon selectivity with time on stream for the conversion of pure 2-MTHF over SiO 2 /Al 2 O 3 are shown in Figure 3. The conversion based on the products formed decreases from 6.6% at 2 h to 3.8% at 6.1 h time on stream.…”

Section: Acs Catalysismentioning

confidence: 99%

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Ring Opening of Biomass-Derived Cyclic Ethers to Dienes over Silica/Alumina

et al. 2017

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We show that cyclic ethers, such 2-methyltetrahydrofuran (2-MTHF), can undergo dehydration to produce pentadienes over SiO2/Al2O3. The catalyst exhibited reversible deactivation due to coke deposition, with the yield to pentadienes decreasing from 68% to 52% at 623 K over 58 h time on stream. A reaction network for 2-MTHF dehydration was proposed on the basis of the results of space time studies. Pentadienes can be produced directly by a concerted hydride shift and dehydration of carbenium intermediates or indirectly through dehydration of pentanal and pentenol. Reaction kinetics studies were performed at temperatures ranging from 573 to 653 K and 2-MTHF partial pressures from 0.21 to 2.51 kPa. The apparent activation energy barrier for 2-MTHF conversion to pentadienes and the reaction rate order for ring opening were determined to be 74 kJ mol–1 and 0.24, respectively, indicating strong interaction between 2-MTHF and the SiO2/Al2O3 surface. Other solid acids such as γ-Al2O3, H-ZSM-5, and Al-Sn-Beta were found to be active for 2-MTHF dehydration to pentadienes. The rate of ring opening decreased in the order 2,5-dimethyltetrahydrofuran > 2-MTHF > tetrahydropyran > tetrahydrofuran. Over SiO2/Al2O3, the dehydration of 2,5-dimethyltetrahydrofuran resulted in 75% yield to hexadiene isomers.

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Section: Resultsmentioning

confidence: 99%

Section: Acs Catalysismentioning

confidence: 99%

Ring Opening of Biomass-Derived Cyclic Ethers to Dienes over Silica/Alumina

et al. 2017

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“…[39][40][41] Both protonation and dehydration are reversible and can contribute to the effective H for MBO, but they are believed to be rapid and thus do not contribute to the observed irreversible uptake of MBO. 3-methyl-2-butene-1-ol is also likely to undergo pinacol rearrangement, which would potentially lead to 3-methylbutanal.…”

Section: Discussionmentioning

confidence: 99%

“…Dehydration is reversible, and water molecules can add to either ion, giving 2-methyl-3-butene-2-ol (MBO) or 3-methyl-2-butene-1-ol. The equilibrium between MBO, 3-methyl-2-butene-1-ol, and protonated isoprene has been observed in 25−50 wt % sulfuric acid solutions at 25 °C. − Both protonation and dehydration are reversible and can contribute to the effective H for MBO, but they are believed to be rapid and thus do not contribute to the observed irreversible uptake of MBO. 3-methyl-2-butene-1-ol is also likely to undergo pinacol rearrangement, which would potentially lead to 3-methylbutanal.…”

Section: Discussionmentioning

confidence: 99%

The Uptake of Methyl Vinyl Ketone, Methacrolein, and 2-Methyl-3-butene-2-ol onto Sulfuric Acid Solutions

et al. 2006

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To investigate the link between molecular structure, reactivity, and partitioning of oxygenated organic compounds in acidic aerosols, the uptake of three compounds found in the atmosphere, methyl vinyl ketone (MVK), methacrolein (MACR), and 2-methyl-3-butene-2-ol (MBO), by sulfuric acid solutions has been measured using a rotated wetted-wall reactor (RWW) coupled to a chemical ionization mass spectrometer (CIMS). MVK was found to partition reversibly into 20-75 wt % H 2 SO 4 solutions, and we report Henry's law coefficients between 20 and 7000 M atm -1 over this range. A chemical reaction for MVK was likely responsible for the uptake observed for 80-96 wt % H 2 SO 4 solutions. We derive an upper limit to the aldol self-reaction rate coefficient for MVK in 80 wt % solution of ∼3 M -1 s -1 . MACR partitioned reversibly over most of the acidity range, and in contrast to that for MVK, the Henry's law coefficient was relatively independent of H 2 SO 4 content. These differences indicate that the increase of the coefficient with acidity is likely due to the ability of the carbonyl molecule to form an enol. These results indicate that aldol condensation can be facile in concentrated sulfuric acid solutions, but it should be negligibly slow in dilute acid solutions such as tropospheric aerosols. MBO uptake could be explained by a Henry's law coefficient that decreases slightly as acid content varies from 20 to 55 wt % H 2 SO 4 ; we also measured the value in water, 70 M atm -1 at 298 K. A steady-state uptake of MBO was observed onto 40-80 wt % H 2 SO 4 solutions, a reaction product was observed, and the reaction was tentatively identified as Pinacol rearrangement. Similar rearrangements could be at the origin of some substituted oxygenated species found in atmospheric aerosols.

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Kinetic scheme of homogeneous acid-catalyzed transformation of isopentenols

Cited by 2 publications

References 0 publications

Ring Opening of Biomass-Derived Cyclic Ethers to Dienes over Silica/Alumina

Ring Opening of Biomass-Derived Cyclic Ethers to Dienes over Silica/Alumina

The Uptake of Methyl Vinyl Ketone, Methacrolein, and 2-Methyl-3-butene-2-ol onto Sulfuric Acid Solutions

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