Mixing calorimetry

Zollweg J A 1994 Mixing calorimetry at cryogenic conditions Solution Calorimetry, Experimental Thermodynamics... 

Mixing Calorimetry Instantaneous heat of mixing, AHMI)aNG Gas generation rates Isothermal, from ambient to 150°C Cannot test multi-phase systems... 

Mixing calorimetry Technique used to measure heat evolved upon instantaneous mixing of two or more chemicals usually designed to be rapid (15 to 45 minutes), operating over the range of-50 to 200 degrees Celsius (°C). 

The enthalpy change associated with formation of a thermodynamically ideal solution is equal to zero. Therefore any heat change measured in a mixing calorimetry experiment is a direct indicator of the interactions in the system (Prigogine and Defay, 1954). For a simple biopolymer solution, calorimetric measurements can be conveniently made using titra-tion/flow calorimeter equipment. For example, from isothermal titration calorimetry of solutions of bovine P-casein, Portnaya et al. (2006) have determined the association behaviour, the critical micelle concentration (CMC), and the enthalpy of (de)micellization. 

Thermodynamic calculations should be made early in a hazard evaluation. However, when assumptions are made regarding end products, the calculations should be backed up by other tests such as the DSC, mixing calorimetry and possibly ARC. 

A survey of different experimental techniques used in mixing calorimetry was given very recently by Gaune-Escard (2002). Calorimetry for the determination of mixing enthalpy can be divided into two groups for temperatures up to 1200 K and above 1200 K. Several experimental techniques may be used for the determination of mixing enthalpies. The main problem met in all of them is the elimination of all side effects arising from ... 

Mixing calorimetry above 1200K. For temperatures above 1200K, different calorimeters should be used because of construction material restrictions. Due to considerable difficulties with the homemade calorimeters, in the majority of cases, commercial equipment is used. One of the most widespread devices working up to 1800 K is the calorimeter Setaram. The whole calorimetric assembly comprise the following parts. 

It should be, however, noted that no apparatus or method can be considered universal in the domain of high-temperature mixing calorimetry, and adaptations should always be made in accordance with the particular requirements of the system under investigation. 

Classic mixing calorimetry represents the historically most important means for the determination of heat capacities. For this purpose, a sample of temperature Ts is introduced directly into the calorimeter liquid, which has the temperature Tini. Thereupon the calorimeter liquid assumes the temperature Tfin after... 

Mixing calorimetry with water as the calorimeter liquid was already introduced in the mid-eighteenth century for the measurement of heat capacities. Calibration was done likewise with water until the mid-nineteenth century. For this purpose, a given mass of water m (specific heat capacity =1 cal g at that time) of known temperature %, was poured into the calorimeter, and the subsequentiy established temperature of the mixture Tg was measured. Thus,... 

BRU Bmnacci, A., Yin, J., Pedemonte, E., and Truturro, A., A study on polymer-polymer interactions through mixing calorimetry, Thermochim. Acta, 111, 117, 1993. 

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