Meilan Wang,Tao He,Yanfei Pan,Weiping Liao,Shangzhou Zhang,Wei Du
Hydrolysis of tetrabutyl titanate (TBT) and crystallization from hydrolyzed intermediates were carried out in a simple ternary system including n -octanol, TBT and water. Anatase TiO 2 nanocrystals (NCS) were prepared with precise size control below 10 nm. The hydrolysis rate at different water concentration ( C water ) was evaluated by measuring the induction time before turbidity changing of the synthetic solution. Fourier transform infrared spectrum (FT-IR) and thermogravimetric/differential thermal analysis (TG/DTA) techniques were applied to make clear the composition of hydrolyzed intermediates obtained at different C water . Powder X-ray diffraction (XRD) technique was used to track the crystallization process of TiO 2 NCS. Transmission electron microscopy (TEM), XRD, FT-IR and TG/DTA techniques were used to characterize the particular properties of NCS. The C water controlled mechanism responsible for the slow hydrolysis and crystallization were discussed. Since no other organic capping ligands or rapid injecting techniques were used to limit NCS’ growth and the solvent n -octanol can be easily separated and reused, this simple synthetic process is of green chemistry and has application potential in large-scale preparation of inorganic NCS.
Aiming to investigate the impacts of n -octanol addition on the oxidation reactivity, morphology and graphitization of diesel exhaust particles, soot samples were collected from a four-cylinder turbocharged diesel engine fueled with D100 (neat diesel fuel), DO15 (85% diesel and 15% n -octanol, V/V ) and DO30 (70% diesel and 30% n -octanol, V/V ). All tests were conducted at two engine speeds of 1370 and 2150 r/min under a fixed torque of 125 N·m. The soot properties were characterized by thermogravimetric analyzer (TGA), transmission electron microscopy (TEM) and Raman spectroscopy (RS). The higher volatile organic fraction content, lower soot oxidation temperatures and lower activation energy from TGA results indicated that both the increasing n -octanol concentration and engine speed enhanced the soot oxidation reactivity. Additionally, quantitative analysis of TEM images showed that the soot derived from DO30 had the smallest primary particle diameters and fractal dimension, followed by those of soot produced by DO15 and D100. The RS results demonstrated that the n -octanol addition and higher engine speed led to a larger D1-FWHM (D1-full width at half maximum), A D1 /A T (area ratio of D1 band and the total spectral) and A D3 /A T (area ratio of D3 band and the total spectral) as well as a smaller L a (crystallite width), revealing a lower degree of graphitization. Furthermore, the correlations between characterization parameters of soot properties and reactivity were nonlinear.
The liquid–liquid equilibrium (LLE) data for the ternary systems of {n-octanol + ethylene glycol + solvents (water/n-heptane/n-hexane/1-hexene/1-chlorobutane)} at 298.2 K under 101.3 kPa were determined. The solute distribution constant and selectivity were used to analyze the solvent’s extraction ability. Meanwhile, the NRTL and UNIQUAC models were applied to correlate the experimental LLE data, and the binary interaction parameters were obtained. The root mean square deviation (RMSD) between the experimental data measured and the calculated by the NRTL and UNIQUAC models was less than 3%. The binary interaction parameters have been confirmed by GUI-MATLAB.
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