Temperature oscillation calorimetry for the determination of the heat capacity in a small-scale reactor

Richner, Gilles; Neuhold, Yorck-Michael; Papadokonstantakis, Stavros; Hungerbühler, Konrad

doi:10.1016/j.ces.2008.04.048

Cited by 13 publications

(10 citation statements)

References 46 publications

(36 reference statements)

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“…In our case, we consider only the temperature of the reactor, T r , and of the jacket, T j : q̇ acc = C p , r d T r d t + C p , j d T j d t C p, r is the total heat capacity of the bulk [J/K], and C p, j is the total heat capacity of the calorimeter [J/K], including the jacket and the vessel, commonly called calorimeter constant . C p, r is calculated experimentally with temperature oscillation calorimetry, and C p, j is calibrated from an experiment without chemical reaction, applying a temperature ramp. The derivatives of the temperatures were calculated employing a Savitzky−Golay filter, with the following parameters: 121 data points, corresponding to 12.1 s of experiment, and a sixth-order polynomial fit.…”

Section: Methodsmentioning

confidence: 99%

“…The advantages are the following: (a) with temperature oscillation, even during the course of a reaction, the heat capacity can be determined, and (b) heat capacity of the inserts (embedded probes), the stirrer, the optional baffles, and the heater are accounted for. For details on temperature oscillation calorimetry, we refer to Richner et al 28 As the mass of reactants known and the vessel content is assumed to be perfectly mixed, λ and F of the bulk are not required.…”

Section: Appendix Amentioning

confidence: 99%

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Nonisothermal Calorimetry for Fast Thermokinetic Reaction Analysis: Solvent-Free Esterification ofn-Butanol by Acetic Anhydride

Richner¹,

Neuhold²,

Hungerbühler³

2010

Org. Process Res. Dev.

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An enhanced small-scale reaction calorimeter has been built for nonisothermal applications. Its unique design, combining compensation heater and heat flow sensors together with a solid intermediate thermostat is particularly suited for data oriented process development (determination of chemical reaction parameters, i.e. rate constants, reaction enthalpies, and reaction monitoring with optional in situ devices) in a wide range of applications in chemical and life-science oriented industries. The performance of the calorimeter is successfully demonstrated for kinetic investigation under nonisothermal conditions. Three different methods for determining the time-resolved reaction heat have been tested. The first is based on the traditional heat balance, the second on the twin principle, while the third is a novel method based on a rigourous heat flow modelling using mathematical finite methods. As a case study, we investigated the esterification of n-butanol with acetic anhydride catalysed by tetramethylguanidine using a temperature ramp from 30 to 80 °C. Each method accounts differently for the dynamics and the heat accumulation in the system. However, all three methods show minor differences in the resulting kinetic parameters and reaction enthalpies. In this temperature range, kinetic and mechanistic analysis resolved two competitive parallel catalytic and noncatalytic steps.

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Section: Methodsmentioning

confidence: 99%

Section: Appendix Amentioning

confidence: 99%

Nonisothermal Calorimetry for Fast Thermokinetic Reaction Analysis: Solvent-Free Esterification ofn-Butanol by Acetic Anhydride

Richner¹,

Neuhold²,

Hungerbühler³

2010

Org. Process Res. Dev.

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“…As errors on both the heat flow and the C p equally affect the calculation of the adiabatic temperature increase, it is important to know the experimental error of the determination of C p , and which factors influence it. The measurement of the error on C p has been described as being less than 0.5% by differential scanning calorimetry and 4 to 10.5% by temperature oscillation calorimetry, but to the best of our knowledge, the error on C p in a RC1e has hitherto not been published.…”

Section: Experimental Error In the Measurement Of C Pmentioning

confidence: 99%

Determination of Accurate Specific Heat Capacities of Liquids in a Reaction Calorimeter, by Statistical Design

Alozie

Courtes

et al. 2011

Org. Process Res. Dev.

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A method using statistical design is proposed to determine the measurement error of specific heat capacities (Cp) of liquids in any reaction calorimeter. This method only takes into account the experimental specific heat of the liquid, its volume and the reactors stirring rate. With the RC1e calorimeter used in this study, the Cp measured by its QuickCal mode was overestimated by up to 0.4 J 3 g À1 3 K À1 , whereas with its RTCal mode, more accurate values of Cp (( 0.2 J 3 g À1 3 K À1 ) were obtained. The statistical model obtained based on the QuickCal mode predicts experimental conditions which improve the accuracy of Cp, and could also be used to correct the value of Cp in the rest of the experimental domain. The corrected values of Cp for test solvents using this model were close to those cited in literature (e5%). As an application, the specific heat capacities at 25 °C of less well documented solvents were determined: anisole, ethyltertiobutylether, methyl-tetrahydrofurane, diethoxymethane, dimethyl-ethyleneurea and dimethylpropyleneurea.

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“…These conditions are fulfilled when the jacket of the reactor has a constant temperature. The constant jacket temperature is set to a defined temperature in order to prevent net heat exchange between the environment and the reactor volume [40][41][42] . However, the small temperature increase of approximately 0.05 °C, still causes some heat losses.…”

Section: Reactor Set-upmentioning

confidence: 99%

Characterization method for mass mixing in batch reactors based on temperature profiles

Camps

Moens

Groth

et al. 2020

Chemical Engineering Research and Design

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Measuring mass mixing in batch reactors is of great interest to prevent yield losses during scale-up of reactions. In this work, we present a novel tool to accomplish this: the heat pulse method. This is a thermal-based technique consisting of a local heat pulse, applied electrically or by a hot liquid injection, during 10 seconds at a power of 5 to 15 W and subsequent measurement of temperature increase at locations of interest. The 95% mixing time from corrected and smoothed temperature profile characterizes heat mixing. A heat mixing model identifies the contributions of thermal conduction and convection and hereby relates local heat and mass mixing in a 800 mL in

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Temperature oscillation calorimetry for the determination of the heat capacity in a small-scale reactor

Cited by 13 publications

References 46 publications

Nonisothermal Calorimetry for Fast Thermokinetic Reaction Analysis: Solvent-Free Esterification ofn-Butanol by Acetic Anhydride

Nonisothermal Calorimetry for Fast Thermokinetic Reaction Analysis: Solvent-Free Esterification ofn-Butanol by Acetic Anhydride

Determination of Accurate Specific Heat Capacities of Liquids in a Reaction Calorimeter, by Statistical Design

Characterization method for mass mixing in batch reactors based on temperature profiles

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