Application of Calorimetry Technique to Estimate Conversion of Polymerization Reactions in a Standard Lab‐Scale Reactor

Esposito, Marcelo; Sayer, Cláudia; Machad, R. A. F.; Araújo, Pedro Henrique Hermes de

doi:10.1002/masy.200651354

Cited by 5 publications

(3 citation statements)

References 6 publications

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“…Assuming that the polymerisation reaction is the main reaction occurring, the polymerisation rate R p can be defined as the quotient of the reaction heat . Q r and the reaction enthalpy −∆H [37]:…”

Section: Calorimetry: Heat Of Reaction Curves Reaction Enthalpymentioning

confidence: 99%

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Kinetic Study on Acrylic Acid Polymerisations in Isopropanol

Betz¹,

Westhues²,

Pauer³

2021

Applied Sciences

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The radical polymerisation of acrylic acid is largely concentration dependent and affected by the type of the surrounding solvent. This work investigates reaction rate constants, the activation energy, heat flux and the molecular weight in the industrially relevant synthesis of low molecular mass acrylic acid polymers in 2‑propanol. The polymerisations were carried out isothermally in an RC1e calorimeter with inline Raman spectroscopy for monomer concentration monitoring. For a non-neutralised acrylic acid in isopropanol (150 g/L), a monomer reaction order of 1.73 ± 0.15, an activation energy of 58.6 ± 0.8 kJ/mol (0.5 mol% AIBN) and 88.5 ± 1.5 kJ/mol (1.0 mol% AIBN), and a reaction enthalpy of 66.4 ± 4.8 kJ/mol could be shown. This data is in accordance with the literature values for acrylic acid polymerisation in water. In addition, linear correlations between the respective reaction parameters and the molecular weight for customised polymer synthesis in the range from 1.2 to 1.7 × 104 g/mol could be established. In comparison with aqueous acrylic acid polymerisation, it was found that the reaction rate constants in isopropanol were slower by a factor of approximately 10 under similar reaction conditions.

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Section: Calorimetry: Heat Of Reaction Curves Reaction Enthalpymentioning

confidence: 99%

“…Furthermore, the calorimetric global conversion X calor can be calculated by integrating the polymerisation rate over the time t and dividing it by the initially fed amount of monomer M 0 [37,38]:…”

Section: Calorimetry: Heat Of Reaction Curves Reaction Enthalpymentioning

confidence: 99%

Kinetic Study on Acrylic Acid Polymerisations in Isopropanol

Betz¹,

Westhues²,

Pauer³

2021

Applied Sciences

View full text Add to dashboard Cite

show abstract

“…Assuming that the values of Q Stir and Q RA are negligible compared to the other terms of Equation (9) 28 and writing Q RJ as: all terms in the energy balance, Equation (9), are known directly except for the heat generated by the reaction, Q R , which involves the derivative of the reactor temperature. In order to avoid problems related to noise propagation, a high gain observer for Q R was employed as proposed by Othman et al:20 where θ is the tuning parameter of the observer set to θ = 0.04 and y = T R is the output of Equation (12).…”

Section: Experimental Partmentioning

confidence: 99%

In‐Line Monitoring of Emulsion Polymerization Reactions Combining Heat Flow and Heat Balance Calorimetry

Esposito

Sayer

Araújo

2010

Macro Reaction Engineering

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In‐line monitoring of semi‐batch vinyl acetate emulsion polymerizations was performed combining heat flow and heat balance calorimetry to re‐estimate the overall heat transfer coefficient between the reactor and jacket. The initial UARJ was obtained applying a constant power through an electrical heater to the initial reactor charge. As UARJ changed during the reaction, it was re‐estimated combining the mass and energy balances of the jacket and the reactor and minimizing an objective function in terms of TJ_out. Results showed that good in‐line estimations of conversion can be performed without requiring the use of experimental conversion data to re‐estimate UARJ during the reaction.

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Effect of Cooling Fluid Flow Rate on the Estimation of Conversion by Calorimetry in a Lab‐Scale Reactor

Esposito

Sayer

Machado

et al. 2008

Macromolecular Symposia

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Significant information about polymerization reactions carried out in lab‐scale reactors is lost because sampling is not always possible due to the high viscosity, heterogeneity of the reaction medium or pressurization of the reactor. Thus, monitoring these reactions through calorimetry technique could be very valuable. Nevertheless, standard lab‐scale reactors can present a relatively high residence time of the cooling fluid in the jacket and significant heat loss of the jacket to the surroundings. In the present work, the effect of the cooling fluid flow rate on the estimation of conversion through isothermal and isoperibolic calorimetry during a batch emulsion polymerization was investigated. Results show that the estimation of conversion through isothermal and isoperibolic calorimetry was not significantly affected by the cooling fluid flow rate using heat flow calorimetry. Nevertheless, when employing the energy balance of the jacket and the estimation of the global heat exchange coefficient between the jacket and the surroundings to estimate conversion (heat balance calorimetry) better results were obtained for lower cooling fluid flow rates.

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Application of Calorimetry Technique to Estimate Conversion of Polymerization Reactions in a Standard Lab‐Scale Reactor

Cited by 5 publications

References 6 publications

Kinetic Study on Acrylic Acid Polymerisations in Isopropanol

Kinetic Study on Acrylic Acid Polymerisations in Isopropanol

In‐Line Monitoring of Emulsion Polymerization Reactions Combining Heat Flow and Heat Balance Calorimetry

Effect of Cooling Fluid Flow Rate on the Estimation of Conversion by Calorimetry in a Lab‐Scale Reactor

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