On the Absorption of Isobutene and <i>trans</i>-2-Butene in Sulfuric Acid Solutions

Brilman, Derk Willem Frederik; Swaaij, W.P.M. van; Versteeg, Geert

doi:10.1021/ie970129q

Cited by 7 publications

(12 citation statements)

References 24 publications

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“…Within the range 50-80 mass % H 2 SO 4 the deviations between model prediction and experimental determined data points are relatively large but still within 30% (which is relatively accurate if one considers that the protonation reaction rate constant varies over several decades in the range of acid concentrations). 1 The general trend is reasonably well described. This technique will be used for estimating the isobutene and trans-2-butene solubilities in aqueous sulfuric acid solutions.…”

Section: Estimation Of Solubility Of Gas-phase Components In Electrolmentioning

confidence: 70%

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Diffusion Coefficient and Solubility of Isobutene and trans-2-Butene in Aqueous Sulfuric Acid Solutions

2001

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The diffusion coefficient and the physical solubility of isobutene and trans-2-butene in aqueous sulfuric acid solutions cannot be determined experimentally due to the occurrence of fast chemical reactions. In the present contribution these physicochemical parameters are estimated. For the solubility an isobutaneisobutene analogy is applied for the range 0-100% H 2 SO 4 . A correlation technique, initially proposed by Rudakov et al., 11 was used for describing the experimental data at low acid concentrations and for estimation purposes for more concentrated solutions. Diffusion coefficients for inert gases in electrolyte solutions were measured using a modified diaphragm cell. It was found for CO 2 and N 2 O in KCl solutions that the diffusion coefficient is not a function of the ionic strength of the electrolyte solution and therefore not a function of the activity coefficient of the diffusing component. It appears that the correlation Dη 0.6 ) constant holds up to 80 mass % sulfuric acid, as is the case for several other aqueous electrolyte solutions. Diffusion coefficients for butenes in sulfuric acid solutions (up to 96 mass %) are estimated from CO 2 coefficients in these solutions.

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Section: Estimation Of Solubility Of Gas-phase Components In Electrolmentioning

confidence: 70%

“…When the above results and methods are used for interpretation of isobutene and trans-2-butene absorption fluxes in aqueous sulfuric acid solutions in order to retrieve kinetic data, 1 it is found that a significant part of the observed discrepancy in these kinetic data as found in the literature could be resolved.…”

Section: Diffusion Coefficientsmentioning

confidence: 97%

Diffusion Coefficient and Solubility of Isobutene and trans-2-Butene in Aqueous Sulfuric Acid Solutions

2001

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“…The reaction kinetics under Koch reaction conditions ( >75 wt.% H 2 SO 4 ) are not well known. Recent work [1] for the kinetics of the pivalic acid formation starting with isobutanol (and in a few experiments tert-butanol) as reactant has shown for these reactants that in absence of mass transfer limitations the carbocation formation is rate determining.…”

Section: Reaction Mechanism and Reaction Kineticsmentioning

confidence: 99%

“…In the industrially applied fully backmixed stirred tank reactors the hydrocarbon reactants and the acids produced constitute a dispersed organic liquid phase. Previous work has shown that the presence of the reaction product in the catalyst phase significantly affects the reaction kinetics [1]. The relatively small reactants used in this study, isobutene and tert-butanol, form a gas-liquid two-phase system with the sulfuric acid catalyst phase under the conditions studied.…”

Section: Introductionmentioning

confidence: 97%

Mass transfer effects in the H2SO4 catalyzed pivalic acid synthesis

et al. 2001

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The synthesis of carboxylic acids from alkenes, carbon monoxide and water according to the Koch process is usually carried out in a stirred gas-liquid-liquid multiphase reactor. Due to the complex reaction system with fast, equilibrium reactions and fast, irreversible reactions the yield and product distribution depend on a number of process parameters. The effect of some of these parameters was studied for the production of pivalic acid, using sulfuric acid as a catalyst. For the 96 wt.% sulfuric acid catalyst solution used the main reactions are relatively fast with respect to mass transfer and mixing. Therefore, aspects like the position of the injection point, inlet concentration, agitation intensity and injection rate all influence the yield obtained. The presence of an inert organic liquid phase was found to be beneficial, due to a combined effect of enhanced gas-liquid mass transfer and a 'local supply' effect for carbon monoxide near the hydrocarbon reactant inlet.

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“…The protonation of ole"ns leading to the same C carbocations, has been studied more frequently in literature, see e.g. Brilman, Swaaij and Versteeg (1997) for a recent overview and update of data for isobutene and trans-2-butene. In these cases the protonation kinetics depend strongly on the acid strength of the catalyst solution and a log-linear relationship between the apparent "rst-order (in the alcohol or alkene concentration) reaction rate constant for the protonation reaction and the Hammett acidity function Ho is found.…”

Section: The Carbocation Formationmentioning

confidence: 99%

Gas–liquid–liquid reaction engineering: the Koch synthesis of pivalic acid from iso- and tert-butanol; Reaction kinetics and the effect of a dispersed second-liquid phase

Brilman

Swaaij

Versteeg

1999

Chemical Engineering Science

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. Gas-liquid-liquid reaction engineering: the Koch synthesis of pivalic acid from iso-and tert-butanol; Reaction kinetics and the effect of a dispersed second-liquid phase. Chemical Engineering Science, 54(21), 4801-4809. https://doi.org/10.1016/S0009-2509(99)00197-9 Copyright Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. AbstractIn gas}liquid}liquid reaction systems with fast parallel and consecutive reactions the e!ects of mass transfer and mixing on the product yield can be signi"cant. The Koch synthesis of pivalic acid, using sulfuric acid as catalyst, was chosen to study these e!ects. Reaction kinetics and the e!ect of the catalyst-phase composition have been investigated by using isobutanol as reactant. For studying the e!ect of an immiscible liquid phase on the reaction products obtained, the more reactive tert-butanol was used. Pivalic acid can be produced from isobutanol using sulfuric acid as a catalyst solution with 2-methylbutanoic acid as main byproduct, if gas}liquid mass transfer limitations are excluded. The selectivity towards 2-methylbutanoic acid is generally less than 20% and decreases strongly with decreasing acidity. The reaction is "rst order in isobutanol and dehydration is likely to be rate determining. The presence of pivalic acid and isobutanol strongly reduces the apparent reaction rate constant by decreasing the solution acidity (Ho). For the industrially applied backmixed reactors in the Koch synthesis, this may imply that these operate at much lower values for Ho. On addition of an immiscible heptane phase, the reaction products are extracted to some extent and this adds to maintaining a high catalyst solution acidity. Using tert-butanol, the yield and pivalic acid selectivity was found to depend strongly on CO transport to the reaction zone through gas}liquid mass transfer and mixing. The presence of an immiscible heptane phase increased the product yield and selectivity towards pivalic acid signi"cantly.

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On the Absorption of Isobutene and trans-2-Butene in Sulfuric Acid Solutions

Cited by 7 publications

References 24 publications

Diffusion Coefficient and Solubility of Isobutene and trans-2-Butene in Aqueous Sulfuric Acid Solutions

Diffusion Coefficient and Solubility of Isobutene and trans-2-Butene in Aqueous Sulfuric Acid Solutions

Mass transfer effects in the H2SO4 catalyzed pivalic acid synthesis

Gas–liquid–liquid reaction engineering: the Koch synthesis of pivalic acid from iso- and tert-butanol; Reaction kinetics and the effect of a dispersed second-liquid phase

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