The heat capacities of nine room-temperature ionic liquids (ILs) were measured in an adiabatic calorimeter. The obtained results were compared with the literature data. It was demonstrated that in most works the uncertainty of the heat capacity measurements for ILs is underestimated, and the possible causes of this were discussed. With the use of the set of 19 ILs for which the reliable heat capacity data and the density data are available, it was found that the quotient of heat capacity at constant pressure to volume for these liquids remains constant within ( 5 % at a given temperature and linearly changes with temperature in the temperature range of (258 to 370) K. It was demonstrated that the selection of an IL for technical applications is limited not by its heat capacity but by the other parameters.

Heat capacities and enthalpies of formation were determined for the well-characterized samples of cellulose of different origins. The obtained experimental results allowed us to obtain the accurate values of thermodynamic properties for this material. It was demonstrated that the heat capacity and entropy of cellulose samples can be linearly related with their crystallinity index. The equilibria of the processes of cellulose gasification were considered. The adiabatic temperatures of the gasification and energetic characteristics of the products of cellulose thermolysis were evaluated. ' INTRODUCTIONThe use of plant biomass as fuel and raw material for chemical processing is being increased. 1 The effective operation of energy and processing plants using plant biomass is possible if their working conditions are thermodynamically justified. However, very limited information about thermodynamic properties of cellulose and lignin, the major components of the stem part of biomass, is available. In refs 2 to 3 the heat capacity of cellulose fibers was measured in a drop calorimeter. The heat capacity changes near T = 400 K corresponding to the glass transition were observed. Hatakeyama et al. 4 measured heat capacity of cellulose in the temperature range of (330 to 450) K by differential scanning calorimetry (DSC) and found no anomalies below T = 440 K. In refs 5 to 8 the heat capacity of cellulose was determined in adiabatic calorimeters. Karachevtsev and Kozlov 6 measured the heat capacity in a range of temperatures of (80 to 300) K for two samples dried by different methods and found that the results depend on the method of drying. Uryash et al. 8 determined the heat capacity for cotton microcrystalline cellulose in the temperature range (80 to 330) K. In ref 8 the anomalies at 291 K, 343 K, and 403.5 K were observed in the differential thermal analysis (DTA) curve, and the first anomaly was also found in the heat capacity curve. The energies of combustion for various samples of cellulose were also reported in ref 8 though the samples were not characterized by the ash content.In this work the heat capacities in the temperature range of (5 to 370) K and the enthalpies of formation were determined for the samples of cellulose of different origins and degrees of crystallinity. The obtained experimental results allowed us to obtain the reliable values of thermodynamic properties of cellulose required for the calculation of equilibria of the reactions with the participation of this compound, the adiabatic temperatures of the processes of its gasification, and energetic characteristics of the products of cellulose thermolysis.

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Heat capacity for 1-butyl-3-methylimidazolium tosylate [C4mim][Tos] in the temperature range (5 to 370) K has been measured by adiabatic calorimetry. Temperatures and enthalpies of its phase transitions have been determined. Thermodynamic functions have been calculated for crystalline and liquid states. The thermal stability of [C4mim][Tos] has been determined by scanning calorimetry. Mutual solubility in binary mixtures of [C4mim][Tos] with water and caprolactam has been investigated, and the activity coefficients have been calculated. Heat capacities for three mixtures of [C4mim][Tos] with water have been measured by adiabatic calorimetry. On the basis of the calorimetric and SLE measurements for ([C4mim][Tos] + water) samples the heat capacity anomalies have been interpreted.