Dissociation constant of bisulfate ion in aqueous sodium chloride solutions to 250.degree.C

Dickson, Andrew G.; Wesolowski, David J.; Palmer, Donald A.; Mesmer, R.E.

doi:10.1021/j100383a042

Cited by 225 publications

(231 citation statements)

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“…The k * values showed an evident dependence on temperature as well as on H 2 SO 4 initial concentration, and thus an acid catalysis correlation, taking into account the H 3 O + influence on the reaction, needed to be formulated. It is known from literature that the second dissociation constant of sulphuric acid varies significantly with temperature and with the ionic strength of the solution, Dickinson et al [1990], Marshall and Jones [1966], Quist et al [1965], and it is important to take into account those temperature effects in the kinetic formulation as observed by many authors, Antal Jr et al [1991], Zeitsch [2000]. Within the range of conditions of interest for this work, aqueous sulphuric acid can be considered with good approximation to be present as H 3 O + and HSO − 4 .…”

Section: Resultsmentioning

confidence: 99%

Bioenergy II: Furfural Destruction Kinetics during Sulphuric Acid-Catalyzed Production from Biomass

Marcotullio¹,

Jong²,

Cardoso³

et al. 2009

International Journal of Chemical Reactor Engineering

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The interest for furfural has increased in the last years due to its potential for competing with oil derivatives as platform chemical. In addition, furfural, derived from C 5 sugars, can play a key role in the valorization of the hemicellulose contained in biomass when considering the development of a modern biorefinery concept. The development of such new and competitive biorefinery processes must be based on accurate kinetic data for the reactions involving furfural in the conditions used for its production.This work addresses the determination of furfural destruction kinetics in aqueous acidic environment, using sulphuric acid as catalyst, in the temperature range 150 -200• C, acid concentration range 36.4 -145.5 mM and furfural initial concentration between 60.4 and 72.5 mM. These studies were carried out using a recently built lab-scale titanium reactor that enables liquid phase reactions in a relatively broad range of conditions.The obtained results show that destruction of furfural follows first-order reaction kinetics within the range of temperature and acid concentration evaluated. Moreover, the proposed kinetic model takes into account the effects of temperature and acid dilution on the ions activity, and thus H 3 O + , by using the electrolyte Non-Random Two-Liquid (eNRTL) model. By using this approach, the rate constant dependence on temperature could be described by the Arrhenius law and thus the activation energy could be estimated as being 125. Contrarily to what is reported in previous works, formic acid formation from furfural under the tested conditions can be regarded as playing a far less pronounced role than suggested before.

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Section: Resultsmentioning

confidence: 99%

Bioenergy II: Furfural Destruction Kinetics during Sulphuric Acid-Catalyzed Production from Biomass

Marcotullio¹,

Jong²,

Cardoso³

et al. 2009

International Journal of Chemical Reactor Engineering

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“…Carbonate chemistry was standardized using CO2SYS (Lewis et al, 1998) and the stoichiometric equilibrium constants K 1 and K 2 for carbonic acid determined by Lueker et al (2000), K S for sulphuric acid determined by Dickson et al (1990) and K B for boric acid following Uppström (1974). Calculated pH is reported on the total scale.…”

Section: Carbonate Chemistry Standardizationmentioning

confidence: 99%

A Conceptual Model for Projecting Coccolithophorid Growth, Calcification and Photosynthetic Carbon Fixation Rates in Response to Global Ocean Change

2018

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Temperature, light and carbonate chemistry all influence the growth, calcification and photosynthetic rates of coccolithophores to a similar degree. There have been multiple attempts to project the responses of coccolithophores to changes in carbonate chemistry, but the interaction with light and temperature remains elusive. Here we devise a simple conceptual model to derive a fit equation for coccolithophorid growth, photosynthetic and calcification rates in response to simultaneous changes in carbonate chemistry, temperature and light conditions. The fit equation is able to account for up to 88% of the variability in measured metabolic rates. Equation projections indicate that temperature, light and carbonate chemistry all have different modulating effects on both optimal growth conditions and the sensitivity of responses to extreme environmental conditions. Calculations suggest that a single extreme environmental condition (CO 2 , temperature, light) will reduce maximum rates regardless of how optimal the other environmental conditions may be. Thus, while the response of coccolithophores to ocean change depends on multiple variables, the one which is least optimal will have the most impact on overall rates. Finally, responses to ocean change are usually reported in terms of cellular rates. However, changes in cellular rates can be a poor predictor for assessing changes in production at the community level. We therefore introduce a new metric, the calcium carbonate production potential (CCPP), which combines the independent effects of changes in growth rate and cellular calcium carbonate content to assess how environmental changes will impact coccolith production. Direct comparison of CO 2 impacts on cellular CaCO 3 production rates and CCPP shows that while the former is still at 45% of its pre-industrial capacity at 1,000 µatm, the latter is reduced to 10%.

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“…Some works have made use of the electrolytes NRTL (eNRTL) [16,39] and Pitzer model [10] for calculating the thermodynamic properties of the aqueous electrolyte systems. In this work, by applying the eNRTL model implemented in the commercial software Aspen Plus (V-7.2), the ion activity coefficients, dissociation constants and hydronium ion concentrations have been calculated for the different reaction solutions.…”

Section: Thermodynamicsmentioning

confidence: 99%

The effects of combined catalysis of oxalic acid and seawater on the kinetics of xylose and arabinose dehydration to furfural

Hongsiri

Danon

Jong

2014

Int J Energy Environ Eng

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It is known that both acids and salts have a positive catalytic effect on the dehydration of pentoses to form furfural, a potentially attractive platform chemical. In this study the effects of the combined usage of an organic acid, instead of stronger mineral acids, and a saline catalyst is investigated. In order to assess these effects, the kinetics of pentose dehydration to furfural are studied using oxalic acid as the primary catalyst and NaCl or seawater as the secondary saline catalyst. The interactions between these two types of catalysts are complex and are, therefore, also assessed thermodynamically. The addition of salts lowers the activity coefficient of the hydronium ions, but simultaneously favours the dissociation of the organic acid. It turned out that these two effects are of similar magnitude, resulting in a fairly constant hydronium ion activity. Because nonetheless higher furfural yields are obtained using the salts as a secondary catalyst, it is concluded that the salts influence the pentose dehydration mechanism directly. The final furfural yields obtained using oxalic acid as the primary catalyst were only slightly lower than those for similar experiments using HCl. The most distinctive difference between the two acids is the lower reaction rate (and thus longer reaction times) when using oxalic acid. Finally, it was observed that if no acidic catalyst is used, the salts tend to catalyse a loss reaction, which is suppressed when an acid is present.

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Dissociation constant of bisulfate ion in aqueous sodium chloride solutions to 250.degree.C

Cited by 225 publications

References 1 publication

Bioenergy II: Furfural Destruction Kinetics during Sulphuric Acid-Catalyzed Production from Biomass

Bioenergy II: Furfural Destruction Kinetics during Sulphuric Acid-Catalyzed Production from Biomass

A Conceptual Model for Projecting Coccolithophorid Growth, Calcification and Photosynthetic Carbon Fixation Rates in Response to Global Ocean Change

The effects of combined catalysis of oxalic acid and seawater on the kinetics of xylose and arabinose dehydration to furfural

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