To determine the peroxide content of a liquid, the procedure is as follows:

A quantity p (about 5 g, weighed to the nearest 0.01 g) of the liquid to be titrated is placed in an Erlenmeyer flask; 20 cm3 of acetic anhydride and about 1 g of powdered solid potassium iodide are added; the flask is shaken and, after 10 minutes, heated for 3 minutes to about 60°C. When it has been left to cool for 5 minutes,25 cm3of water are added. After this, it is left standing for half an hour, then the liberated iodine is titrated with a decinormal solution of sodium thiosulphate, no indicator being added; complete discoloration indicates the end of the reaction. If n is the number of cm3of thiosulphate solution required, the percentage of peroxide (calculated as H2O2) present in the sample is obtained by the formula:

17n
———
100p

To determine the fluidity of liquid, viscous or pasty substances and mixtures, the following test method shall be used.

Commercial penetrometer conforming to ISO 2137:1985, with a guide rod of 47.5g±0.05g; sieve disc of duralumin with conical bores and a mass of 102.5g±0.05g (see Figure 1); penetration vessel with an inside diameter of 72 mm to 80 mm for reception of the sample.

The sample is poured into the penetration vessel not less than half an hour before the measurement. The vessel is then hermetically closed and left standing until the measurement. The sample in the hermetically closed penetration vessel is heated to 35°C±0.5 °C and is placed on the penetrometer table immediately prior to measurement (not more than twominutes). The point S of the sieve disc is then brought into contact with the surface of the liquid and the rate of penetration is measured.

A substance is pasty if, after the centre S has been brought into contact with the surface of the sample, the penetration indicated by the dial gauge:

(a)after a loading time of 5 s ± 0.1 s, is less than 15.0 mm ± 0.3 mm; or

(b)after a loading time of 5 s ± 0.1 s, is greater than 15.0 mm ± 0.3 mm, but the additional penetrationafter another 55 s ± 0.5 s is less than 5.0 mm ± 0.5mm.

NOTE:In the case of samples having a flow point, it is often impossible to produce a steady levelsurface in the penetration vessel and, hence, to establish satisfactory initial measuring conditions for the contact of the point S. Furthermore, with some samples, the impact of the sieve disc can cause an elastic deformation of the surface and, in the first few seconds, simulate a deeper penetration. In all these cases, it may be appropriate to make the evaluation in paragraph (b) above.

Figure 1 – Penetrometer

Depending on their properties as determined in accordance with tests N.1 to N.5 of the Manual of Tests end Criteria, Part III, section 33, organometallic substances may be classified in Class 4.2 or 4.3, as appropriate, in accordance with the flowchart scheme given in Figure 2.3.5.

NOTE 1:Depending on their other properties and on the precedence of hazard table (see2.1.3.10), organometallic substances may have to be classified in other classes as appropriate.

NOTE 2:Flammable solutions with organometallic compounds in concentrations which are not liable to spontaneous combustion or, in contact with water, do not emit flammable gases in dangerous quantities, are substances of Class 3.

Figure 2.3.5: Flowchart scheme for the classification of organometallic substances in Classes 4.2 and 4.3 b

________________
a If applicable and testing is relevant, taking into account reactivity properties, class 6.1 and 8 properties should be considered according to the precedence of hazard table of 2.1.3.10.
b Test methods N.1 to N.5 can be found in the Manual of Tests and Criteria, Part III, Section 33.

In addition to the provisions referred to or given in the tables of this Part, the general requirements of each Part, Chapter and/or Section are to be observed. These general requirements are not given in the tables. When a general requirement is contradictory to a special provision, the special provision prevails.

NOTE: For proper shipping names used for the carriage of samples, see 2.1.4.1.