Dichloride titanium oxide

Additional toxicological data

Administrative data

Endpoint:

additional toxicological information

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Data source

Reference

Reference Type:

review article or handbook

Title:

Water reactive materials - incorporataion into safety and environmental risk assessments

Author:

Fernie L, Wright P, Kapias T

Year:

2004

Bibliographic source:

Symposium Series No. 150, IChemE

Materials and methods

Test guideline

Qualifier:

no guideline followed

Test material

Test material information

Constituent 1

Reference substance name:

Titanium tetrachloride

EC Number:

231-441-9

EC Name:

Titanium tetrachloride

Cas Number:

7550-45-0

IUPAC Name:

titanium tetrachloride

Details on test material:

- Name of test material (as cited in study report): Titaniumtetrachloride
- Molecular formula (if other than submission substance): TiCl4

Results and discussion

Any other information on results incl. tables

In Method A, the injected water was immediately covered with a white crust of titanium dioxide. Only 27% of the predicted theoretical yield of HCl occurred. In Method B, it appeard that in addition, some HCl that initially escaped as a gas dissolved in the excess water. The yield peaked at 16% of maximum after 1 min and dropped to 6% within 10 min. In the free atmosphere, a smaller fraction of the HCl produced would dissolve in the excess water as a result of advection.

Table 1: Mass of HCl (g) evolved

Time	Method A	Method B
1	0.023	0.023
5	0.039	0.0114
10	0.039	0.091
20	0.039	0.091

It should be noted that the scope of these experiments was simple. Looking at their findings, one could draw the following conclusions: a. The theoretical yield of the reaction was measured to be equal to 27%. This result was based on the stoichiometry of the reaction "one molecule of Tic4 produces 4 molecules of HCI gas". In other words, it was noted that "one molecule of TiCI4 produces about 1 molecule of HCI gas". b. The reaction of liquid TiCl4 with water produces solid particles of a titanium compound. Based on themodynamic calculations, estimation methods and any other relevant information, it was shown that the number of these statements could not realistically represent the liquid phase hydrolysis reaction of TiCl4. Based on the conducted investigation, on the only piece of relevant experimental information and on certain indications found in the literature, the liquid phase hydrolysis reaction is described according to the following:

Tic14 (1) + 3H2O (l,v) -> Ti02 x H20 x 3HC1 (s) + HCl (g) DelatH (1)

According to the above reaction, liquid TiCl4 will react with ground water and atmospheric moisture producing a solid complex or "titanium oxychloride" and hydrogen chloride gas. It is concluded that the above reaction is a realistic representation under TiCl4 excess conditions, expected to be encountered in cases of accidental spills. Furthermore, it is compatible with the findings and conclusions observed in the only experimental work found on the topic. It should be noted that the conducted investigation has shown that the reaction of TiCl4 with water depends on the amount of water available for reaction. It is believed that under water excess conditions, the solid complex will further hydrolyse. possibly yielding titanium dioxide and HCI. When released to the atmosphere, liquid TiCl4 will create a pool that will either boil or evaporate, depending on the amount of water nvailitble for reaction and other parameters. The possibility of solidification is extremely low (m.p.TiCl4, = 250 K). As the pool spreads, will continuously react with any free ground water according to reaction (1). It will also absorb atmospheric moisture. A complex solid of "titanium oxychloride" will be produced by the overall hydrolysis process. These solid particles are assumed to settle onto the bottom of the pool, forming a film. Apart from HCI gas (directly produced by the reactions), TiCl4 will also evolve due to ils relatively high volatility. It should be noted that further experimental work would be necessary to define the exact kinetics and thermodynamics of the TiCl4 liquid phase hydrolysis reaction under different conditions.