Cyanamide

Endpoint summary

Description of key information

Appearance/physical state/colour

The substance Cyanamid F1000 is a colourless, odourless solid (Wildenauer, 2018).

 

Melting point

Melting point determination of Cyanamid F1000 was performed by the capillary method using a hot block heating according to EU guideline A.1 and OECD 102. The mean melting temperature of Cyanamid F1000 is 46.1°C, with a standard deviation of 0.05°C (Wenighofer, 2007).

 

Boiling point

The determination of the boiling point was performed by the method of Siwoloboff according to the OECD Guideline 103 and the EU method A.2. Cyanamid F1000 decomposed before boiling , therefore no boiling temperature of the test substance could be determined. At about 141°C the liquid test substance became solid and fluidified again at 208°C (Wenighofer, 2007)

 

Density

The relative density of Cyanamid F1000 with a pycnometer was determined according to the OECD guideline 109, EU. Method A.3 and the EPA OPPTS 830.7300. The density of Cyanamid F1000 was determined to be 1.23 g/cm3 ± 0.01 at 21.4°C corresponding to 1.23 g/cm3 ± 0.01 at 20°C (Tognucci, 2000)

  

Particle Size distribution

The particle size distribution (volume distribution) of Cyanamid F1000 was measured by laser diffraction with dry dispersing.

The average particle size distribution of three measurements is:

d10: 235 µm

d50: 548 µm

d90: 1006 µm

 

Vapour pressure

The vapour pressure of Cyanamid F1000 was measured by the vapour measure balance method according to the EU method A.4, in 4 different temperatures between 21 and 25.2 °C. The following vapour pressure for Cyanamid F1000 was calculated from the vapour pressure curve (log vapour pressure versus reciprocal temperature) to be: P20°C = 0.51 Pa = 68 mm Hg and P25°C = 1.0 Pa = 133 mm Hg (Eskötter, 1991)

 

Partition coefficient

The partition coefficient octanol/water (Pow or log Pow) of Cyanamid F1000 was performed using the shake flask method at 20°C, according to the OECD Guideline 107 and the EU Method A.8. The octanol/water partition coefficient, Pow, of Cyanamid F1000 was determined to be 0.19 ± 0.01 (logPow = -0.72 ± 0.02) at 20°C (Turner, 2005)

 

Water solubility

A determination of the water solubility of Cyanamid F1000 by the flask method as described in the CIPAC MT 157.2 was attempted. Due to the high water solubility of the compound (850 g/L as given by the manufacturer), even with the lowest quantity of water (40 mL as required by the guideline), a mixture of appro. 400 g Cyanamide F 1000 with 40 mL water was prepared. It is possible that at such a high concentration and test temperature of 30°C an exothermic formation of dicyandiamide and a further reaction to Melamine occur. It was thus not possible to determine the saturation concentration at equilibrium. Results of a preliminary test showed that at pH 7: > 560 g/L and at pH 9-11: >530 g/L (at 20°C), but it is known from the literature that there is a dimerization of cyanamide to dicyanamide at pH values > 5 and a hydrolysis to urea at pH values < 3.8. From the density calibration curve, it could be deduced, that the water solubility of Cyanamid F1000 at 20°C and pH 3.8 is greater than 800 g/L. Cyanamid F1000 could therefore be considered as very soluble (> 10000 mg/L).

 

Solubility in organic solvents

The study examined the solubility of Cyanamid F1000 in organic solvents (of the DAPA list) by the modified flask method according to the OECD Guideline 105. The solubility examination was limited by the BBA classification (danger characterization of the solvents) to 0.1 g/L – 200 g/L. The solubility of Cyanamid F1000 in polar solvents, i-Propanol, Aceton, Methanol and Ethylacetate was measured to be above 210 g/L, while in the non-polar solvents, n-Hexan, Dichlormethan and Toloul the solubility of Cyanamid F1000 was found to be lower than 1 g/L ( 2.4, 410, 670 mg/L respectively). It can be concluded that cyanamide is highly soluble in polar solvents and only slightly soluble in non-polar solvents. These results could be also predicted on the basis of the chemical structure of the cyanamide molecule. It is not to be expected that these values would significantly change with increasing or decreasing temperatures.

 

Surface tension

The surface tension of Cyanamid F1000 was determined by the OECD ring method with an interfacial tensiometer according to the EU method A.5 and the OECD Guideline 115. The mean surface tension of the test substance was 72.86 mN/m, at a temperature of 20.0 °C. According to the EU directive Cyanamid F1000 is not a surface active substance because its surface tension is greater than 60 mN/m.

 

Flash point

Data waiving was presented regarding a flash point study with the test substance Cyanamid F1000, as the study performance is not scientifically justified/technically feasible as Cyanamid F1000 is a solid substance and a flash point is only a relevant property for liquids. Instead flammability tests (UN-tests) were conducted.

 

Auto flammability

Data waiving was presented regarding an auto flammability study with the test substance Cyanamid F1000, as the study performance is not scientifically justified following the REACH Regulation 1907/2006/EC Annex VII section 7.9) because Cyanamid F1000 is a solid with a melting point≤160°C. Results of the UN tests (propagation of a detonative reaction, a deflagration reaction test heating under defined confinement test and an explosive power test) support the data waiving, concluding that Cyanamid F1000 is not a self-reactive substance (BAM expert opinion).

 

Flammability

According to the results of the UN-tests (C.1, C.2, E.1, E.2, E,3) of the UN Recommendations on the Transport of Dangerous Goods, Manual of Tests and Criteria, presented by the BAM (Bundesanstalt für materialforschung und Prüfung) expert opinion, the test substance Cyanamid F1000 is not flammable. It has no tendency to deflagrate (deflagaration rate is less than 35 mm/s) and it is not significantly effected during intense heating under defined confinement (graded under the test criteria as “medium”effect). It is supported by the evaluation and statement of the BAM experts opinion based on results´of these same tests among others (UN tests: A.1, F.3) that Cyanamid F1000 is not a self-reactive substance of class 4.1 of the dangerous goods regulations (and under the GHS/CLP regulations section 2.8.4)

 

Explosiveness

A sample of Cyanamid F1000 was neither shock sensitive nor friction sensitive nor thermally sensitive according to the criteria of EEC test method A.14, the sample has not to be considered to present a danger of explosion.

  

Oxidising properties

Data waiving was presented regarding an oxidising properties study with the test substance Cyanamid F1000, as the study performance is not scientifically justified as the substance does not contain functional groups that belong to the class of compounds that reveal oxidising properties according to the “Guidance on information requirements and chemical safety assessment, Chapter R7a” .

 

Stability in organic solvents and identity of relevant degradation products

In accordance with column 2 of REACH Annex IX, the test on stability in organic solvents and identity of relevant degradation products (required in section 7.15) was not conducted as stability of methenamine in organic solvents was considered to be not critical.

 

Dissociation constant

The titration method described in the OECD test guideline 112, was used for pKa determination of the test item, Cyanamid F1000. The pKa of Cyanamid F1000 could not be calculated because a dissociation reaction was not observed. Aqueous solutions of Cyanamid F1000 (pH value of 6.3) were titrated (with NAOH) but no turning point in the titration curve could be detected, as it would be observed when an acid is titrated with a base. This result confirms the expectation that Cyanamid F1000 does not dissociate in aqueous solutions with pH values of 6 to 9. pH values > 9 were not tested since it is known from the literature that Cyanamid F1000 dimerises to dicyandiamide at pH values of 8 to 9.5. It is concluded that Cyanamid F1000 does not dissociate in aqueous solutions with pH values of environmental relevance (Tognucci, 2000)

 

Storage stability and reactivity towards container material

Results of a 30 days aluminium corrosion test with the test substance Cyanamid L500 and results of a 15 days steel corrosion test with Cyanamid L500 performed at 55°C, showed that the test substance is not corrosive to aluminium and steel. The BAM presented an expert opinion on classification and assignment of Cyanamid F1000 according to the UN dangerous goods regulations. Results of an isothermal storage test were presented, in which the production of dicyandiamide as a function of storage conditions (days and temperatures) was examined. These results showed that Cyanamid F1000 has a long-run stability. In addition other results according to the test methods for self-reactive substances of the UN Manual of Tests and criteria of dangerous goods, completed the conclusion presenting Cyanamid F1000 as stable, not a self-reactive substance and readily available for storage or transport at a mass of 50 kg at 40°C or 50°C respectively (BAM expert opinion).

 

Viscosity

Data waiving was presented regarding a viscosity study with the test substance Cyanamid F1000, as the study performance is technically not feasible, as viscosity is a property of a liquid and Cyanamid F1000 is a solid substance at room temperature.

 

Appearance/physical state/colour

The substance Cyanamid F1000 is a colourless, odourless solid (Safety data sheet , AlzChem, 2006).