Experimental studyofthe liquid phase hydrolysis reaction of titanium tetrachloride
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Titanium tetrachloride (TiCl4) is used in the chemical industry as an intermediate in the production of titanium metal, catalysts and the pigment titanium dioxide. TiCl4 is known to react violently with water to release highly corrosive and toxic hydrogen chloride (HCl) gas. However, industry does not have a common and agreed understanding of the assessment of the extent and severity of the consequences of identified possible major accidents such as an accidental spill of TiCl4. The industry together with the regulatory authorities therefore wishes to make advances on the most appropriate means of estimating the toxic impact from TiCl4 spillage onto wet ground, using validated assumptions on the reactive chemistry and available computer codes. However, very little experimental data are available in the literature on the hydrolysis of TiCl4. Existing spill models are based on theoretical thermodynamic calculations for both the reaction stoichiometry and reaction energy. The objective of the work presented in this paper is to carry out an experimental study of the liquid phase hydrolysis reaction of TiCl4 in order to verify the input parameters used in the existing spill models. Hydrolysis reactions were carried out in excess of TiCl4, since in the case of accidental spills water will most likely be the limited reactant. The experimental investigations showed that the liquid phase hydrolysis reaction of TiCl4 releases HCl gas and produces a solid material. The quantity of solid produced was measured (for a given quantity of added water) and the solid subsequently chemically analysed. An experimental setup also allowed the measurement of the quantity of HCl gas released during the reaction. The liquid phase hydrolysis reaction of TiCl4 was also carried out in both a Dewar calorimeter and in a pseudo-adiabatic calorimeter. These measurements were carried out while varying the water addition rate. The spontaneous, instantaneous and exothermic natures of the reaction were observed and the heat of reaction measured. These analyses were used to test the reaction scheme published in the literature and to propose an experimentally validated reaction stoichiometry and heat of reaction. Crown Copyright 2011.
