Thermophysical Properties of Mixtures of Titanium(IV) Isopropoxide (TTIP) and p-Xylene

Abstract

Titanium(IV) isopropoxide (TTIP) is an important precursor for the production of nanoparticles by spray flame processes. In these processes, the precursor is provided in a solution in a combustible solvent, which is p-xylene here. As no thermophysical data for solutions of TTIP in p-xylene were available in the literature, they were measured in the present work. The vapor-liquid equilibrium was measured at pressures ranging from 20 to 80 kPa. The specific density, viscosity, thermal conductivity, molar isobaric heat capacity, and self-diffusion coefficients were determined experimentally at 101.3 kPa at temperatures between 293.15 and 373.15 K. Sample compositions cover the range from pure TTIP to pure p-xylene. Chemical reactions in the studied system were considered. The experiments were carried out in a way that they do not compromise the results for the thermophysical properties. The vapor-liquid equilibrium data were correlated using the NRTL model. Empirical correlations were established for the other properties. The results provide a rational basis for spray flame process design.

Numerical Study of the Interaction of a Titanium(IV) Isopropoxide/p-Xylene Precursor/Solvent Droplet with Hot Convective Air

“…In the present model, it is assumed that the droplet is spherical all the times, the solubility of air in the liquid is negligible, mass diffusion due to temperature and pressure gradients is negligible, the gas phase is in a quasi-steady state, the droplet evaporates in a non-reacting inert environment, and heat transfer due to radiation is negligible [14]. The real behavior of the TTIP/p-xylene droplets is considered through use of the non-random two-liquid (NRTL) model [15] with appropriate activity coefficients [16].…”

“…Keller et al [16] measured the thermophysical properties of the solutions of TTIP/p-xylene at atmospheric pressure where solvent compositions range from pure TTIP to pure p-xylene. The data include the density, viscosity, thermal conductivity, isobaric specific heat capacity, and vapor-liquid equilibrium.…”

“…The experimental relative standard uncertainty ranges from 0.04 % for the density to 3 % for the mixture viscosity. From the experimental thermophysical data, empirical correlations [16] for these properties were established which are used in the present study. These thermophysical properties are valid within the temperature range of 293.15 K to 373.15 K, beyond which the properties are extrapolated.…”

“…These thermophysical properties are valid within the temperature range of 293.15 K to 373.15 K, beyond which the properties are extrapolated. The vapor pressure of both TTIP and p-xylene is calculated using the Antoine equation for which the parameters are provided by Keller et al [16]. It is expected that the liquid mixture may not be ideal, and therefore, real behavior is considered through the use of activity coefficients of TTIP and p-xylene which [20] are modeled using the non-random two-liquid (NRTL) method [15] by calculating the activity coefficients using the vapor-liquid equilibrium data from Keller et al [16].…”

Thermophysical Properties of Solutions of Iron (III) Nitrate-Nonahydrate in Mixtures of Ethanol and Water

“…For gaining insight into the phenomena in the spray flame and for the design and optimization of the process, simulations are performed, for which information on the thermophysical properties of the precursor solutions [5][6][7] is needed, namely the density, viscosity, thermal conductivity and isobaric heat capacity. In a recent work of our group, these properties were investigated for precursor solutions for the production of titanium oxide nanoparticles 8 . A further motivation to investigate thermophysical properties of precursor solutions is the recent suggestion of a standardized synthesis setup by the SpraySyn initiative 9 , in which also benchmark precursor systems were defined.…”