Isothermal differential calorimetry

Modify the program to study isothermal differential calorimetry by operating at constant temperature for a series of runs. Estimate the activation energy with Arrhenius plots from the rates observed at constant conversion. 

In calorimetry techniques, enthalpy changes accompanying physical or chemical events, whether they are exothermic or endothermic, are measured and monitored either as a function of temperature or time. Thus, a calorimeter is able to collect a heat flux exchanged between the sample and the sensible part of the apparatus, generally made of thermocouples, and to register it. The result is a profile of the rate of enthalpy change, either as a function of temperature as the sample is heated at a known linear rate in differential scanning calorimetry (DSC), or as a function of time when the calorimeter is held at constant temperatnre in isothermal differential calorimetry (DC). 

KNUDSEN J c, ANTANUSE H s, RisBO j and SKIBSTED L H (2002) Induction time and kinetics of crystallization of amorphous lactose, infant formula and whole milk powder as studied by isothermal differential scanning calorimetry, Milchwissenschaft, 57, 543-546. 

Waters, D. N. and J. L. Paddy, "Equations for Isothermal Differential Scanning Calorimetry," Anal. Chem., 60 (1988). 

Christensen, T., B. Svensson, and B.W. Sigurskjold. 1999. Thermodynamics of reversible and irreversible unfolding and domain interactions of glucoamylase from Aspergillus niger studied by differential scanning and isothermal titration calorimetry. Biochemistry 38 6300-6310. 

Jelesarov, I. and H.R. Bosshard. 1999. Isothermal titration calorimetry and differential scanning calorimetry as complementary tools to investigate the energetics of biomolecular recognition. J Mol Recognit 12 3-18. 

Isothermal differential scanning calorimetry (DSC) measurements were carried out to investigate the curing kinetics [85]. Conversion vs time curves of DGEBPA-PACP systems prepared with 1 wt % of catalyst and without catalyst at identical curing temperature are overlaid in Fig. 31. 

Table 2 Comparison of differential calorimetry and isothermal microcalorimetry (4)...

Isothermal differential scanning calorimetry (DSC) tests were performed on three unsaturated polyester (UPE) samples at three different temperatures (100°C, 110°C, and 120°C). The output for the three DSC tests are presented in the Fig. 2.70. On the graph, label which curve is associated with which test temperature. From the curves in Fig. 2.70 estimate the total heat of reaction, Qt ... 

S.A Shackelford, I.W. Beckmann, .S. Wilkes, Deuterium Isotope Effects In Thermal Decompositbn of Liquid 2,4,6-Trinirotobene AppEcation to Mechanistic Studies Using Isothermal Differential Scanning Calorimetry Analysis, . Org. Chem., 42 (1977) 4201. 

The total acidity deterioration and the acidity strength distribution of a catalyst prepared from a H-ZSM-5 zeolite has been studied in the MTG process carried out in catalytic chamber and in an isothermal fixed bed integral reactor. The acidity deterioration has been related to coke deposition. The evolution of the acidic structure and of coke deposition has been analysed in situ, by diffuse reflectance FTIR in a catalytic chamber. The effect of operating conditions (time on stream and temperature) on acidity deterioration, coke deposition and coke nature has been studied from experiments in a fixed integral reactor. The technique for studying acidity yields a reproducible measurement of total acidity and acidity strength distribution of the catalyst deactivated by coke. The NH3 adsorption-desorption is measured by combination of scanning differential calorimetry and the FTIR analysis of the products desorbed. 

Nucleation from the melt has been studied for palm oil, composed of triglycerides of palmitic and oleic acids, and exhibiting at least three polymorphs (van Putte and Bakker 1987). Nucleation curves (induction time x vs temperature T) of palm oil and palm stearin show discontinuities at 297 and 306 °C respectively, indicating the onset of nucleation, and the demarcation of the occurrence of the polymorphs, as confirmed by isothermal Differential Scanning Calorimetry (DSC) studies (Ng I990a,b). 

Calorimetry. Isothermal titration calorimetry (ITC) has recently been proposed as a general method for the determination of enzymatic reaction rates.20 This method is based on the relationship between the power needed to maintain constant temperature and the number of moles of substrate converted. Power, the measured quantity, is related to heat (Q) by differentiation ... 

Jelesarov, I., and Bosshard, H. (1999). Isothermal Titration Calorimetry and Differential Scanning Calorimetry as Complementary Tools to Investigate the Energetics of Biomolecular Recognition, J. Mol. Recognit. 12 3-18. 

Differential scanning calorimetry (DSC) is a sensitive method which has enabled changes in biological systems to be examined providing medical researchers with distinct opportunities. Other thermoanalytical techniques such as thermogravimetry (TG) and isothermal titration calorimetry (ITC) are useful in the evaluation of thermal stability and to measure the heat generated in physical and chemical reactions. 

The kinetics of curing of a poly(phenylene ether)/epoxy resin system has been investigated by an advanced iso-conversional method. Curing experiments with different PPE/EP ratios were carried out using non-isothermal differential scanning calorimetry. It was shown that the curing mechanism of this system is very complicated [21],... 

Although generally a fast process [25,38,39], it was monitored by isothermal differential scanning calorimetry (DSC) in a few instances. The thermal transition is completed within 1-5 min for polymers Pi [40] but requires from 100 to 1000 min for polymer P6 [41]. The value of the Avrami coefficient in P6 suggests a rod-like mechanism for the growth process. While structures Pi appear to be fairly typical, the extremely slow transition reported for polymer P6 seems to represent an exception, at least in the absence of further studies. Chain structure and molecular mass, however, play an important role in the transition kinetics, contrary to the widely held view, inherited from the literature on MLCs, that nematic ordering is always a fast process. 

Herrera, 1., Winnik, M.A. (2013) Differential binding models for isothermal titration calorimetry Moving beyond the Wiseman isotherm. J Phys Chem B, 117 (29), 8659-8672. 

The experimental procedure involves initiation of the polymerization by irradiation followed by cutting off the light after a certain time at a degree of conversion chosen, and monitoring the reaction in the dark. As experimental methods, both isothermal differential scanning calorimetry (photocalorimetry, photo-DSC) [2,6, 7, 18-32] and real-time infrared... 

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