3-aminophenol

Endpoint summary

Description of key information

Appearance/physical state/colour

On the basis of physical observation and using the sense of smell, the appearance of 3-aminophenol was observed to be a white solid crystalline organic compound.

Melting point/Freezing point:

The test item melted in the range of 116 °C to 122 °C (389 K to 395 K).

Boiling point:

The test item 3-aminophenol started boiling at 284 °C (558 K) at ambient barometric pressure (99.0 kPa).

Density:

The relative density of the test item 3-aminophenol was determined to be D4/20= 1.276 g/cm3.

Particle size distribution (Granulometry):

The median particle size L50 of the test items deduced from the particle size distributions is 445.3 µm

Vapour pressure:

Vapour pressure of the test item 3-aminophenol is 0.0187 Pa (mean of three determinations) at 20 °C.

Partition coefficient:

The purpose of the study was to determine the partition coefficent log Pow value of the test chemical by the shake-flask method (OECD 117) . The partition coefficient log Pow value of the test chemical  is determined to be 0.183 at 20 degree celsius at the pH of 7.5 . On the basis of this partition coefficient value it can be concluded that test chemical 3 -aminophenol is hydrophilic in nature.

Water solubility:

The solubility of the test item 3-aminophenol in water was found to be 20100.0 mg/L (20.1 g/L) at 20°C. The resulting saturated solution were acid and colorless.

Surface tension:

In accordance with column 2 of Annex VII, surface activity is not expected and neither is surface activity a desired property of the chemical. Thus for 3-aminophenol,  this endpoint was considered for waiver.

Flash point:

The study does not need to be conducted because the flash point is only relevant to liquids and low melting point solids.

Auto flammability:

In conclusion, the test item m-Aminophenol is considered not to be auto-flammable, according to the criteria as described in the guideline.

Flammability:

The test item m-Aminophenol burned with flame which extinguished before smouldering along 200 mm of the powder rope. Based on this no further testing of the burning rate was required and test item m-Aminophenol (A015) is considered not to be flammable

Explosiveness:

The study does not need to be conducted because there are no chemical groups present in the molecule which are associated with explosive properties.

Oxidising properties:

The study does not need to be conducted because there are no chemical groups present in the molecule which are associated with oxidizing properties and hence the classification procedure does not need to be applied.

pH:

The pH value of 10 g/L solution of 3-aminophenol is observed to be 6.8 at 20°C.

Dissociation constant:

The test item 3-aminophenol shows dissociation properties. The pKa values were found to be in the range of 4.37-5.25 for the forms +HBAH/BAH and in the range of 9.815-10.2 for the forms BAH/BA-.

Viscosity:

As per column 2 of Annex IX of the REACH regulation's, viscosity is an inherent property of a liquid substance of absorbing a stress during deformation which depends on the rate of the deformation. Since viscosity is an inherent property of liquids, this study need not to be conducted because 3-aminophenol is a solid substance as mentioned in section 4.1 of this dossier.

Additional information

Appearance/physical state/colour

On the basis of physical observation and using the sense of smell, the appearance of 3-aminophenol was observed to be a white solid crystalline organic compound.

Supporting data from another experimental report, also supported the selected key study and observed the appearance of 3-aminophenol is as a white coloured, odourless organic cryastalline solid at 35ºC and 960 hPa.

One more supporting data from handbooks, publication and authoritative databases, also supported the selected key study and observed the appearance of 3-aminophenol is a white crystalline solid organic compound.

Melting point/Freezing point:

The purpose of this study was to evaluate the melting point or melting range of the test item by the capillary method using an electronically controlled heating system, according to the A1 method and the OECD 102 guideline, and following the GLP. The determination of the melting point was performed by visual judgement using the capillary method. In the preliminary test the test item started melting at 117 °C. The test item showed five stages of melting. The melting started at 116 °C. At 122 °C the last stage of melting was reached. Hence, the melting point was found in the range of 116 °C to 122 °C (389 K to 395 K).

Other supporting data from reliable handbooks, publications and authoritative databases, also supported the selected key study and

exhibited the melting point of 3-aminophenol as 123°C, 122-123°C and 122 °C respectively.

Boiling point:

The purpose of this study was to evaluate the boiling point of the test item by the capillary method using an electronic controlled heating system, according to the A2 method and the OECD 103 guideline, and following the GLP. The determination of the boiling point was performed by visual judgement using the capillary method. At about 280 °C in the preliminary test, the number of air bubbles increased. To confirm the result obtained in the preliminary test, the determination of the boiling point was performed three times, heat-ing quickly up to 265 °C and afterwards slowly using a heating rate of 1 °C/min. A clear boiling point, as defined in the guideline with a current stream of bubbles evolving from the capillary, was observed at a heating temperature of 284 °C (557 K). The results were evaluated because they fulfill the criteria of repeatability.

Density:

The purpose of the study was to determine the relative density of the test item 3-aminophenol at a specific temperature by using a gas comparison pycnometer, according to the A3 method and OECD 109 guideline, and following the GLP. The relative density of the test item3-aminophenol was determined using the gas comparison method at a temperature of 20 ± 0.5 °C. The determination of the relative density was performed by three-fold measurements of two independent test item samples. The relative density of the test item 3-aminophenol was determined to be 1.276 g/cm³ (= 1276 kg/m³) at 20 °C.

Other supporting data from another experimental report, detemined theBulk density of a substance by calculating the mass per unit volume of liquid. The bulk density of 3-aminophenol is found to be 0.669 g/cm³ at 35°C.

Another studies from authoritative databases also determined the density of 3-aminophenol as 1.195 g/cm³ and 0.99 g/cm³ at 25°C.

Particle size distribution (Granulometry):

Particle size distribution of the test item was determined by laser diffraction method, according to the OECD 110 guideline, the CIPAC MT 187 method and the ISO13320:2009 method, and according to GLP. The median particle size L50 of test item deduced from the particle size distributions is 445.3 µm.

The particle size L10 of test item deduced from the particle size distributions is 105.3 µm.

The particle size L90 of test item deduced from the particle size distributions is 1155 µm.

Vapour pressure:

The purpose of the study was to determine the vapour pressure of the test item 3-aminophenol by isothermal thermogravimetry, according to the A4 method and the OECD 104 guideline, and following the GLP. The evaporation rates of the test item at elevated temperatures and ambient pressure were determined by monitoring the weight loss. The determination of vapour pressure was done using temperatures below melting range. A value of the vapour pressure of the test item was determined using the data obtained above the 70 °C. The vapour pressure of the test item 3-aminophenol at 20 °C (293K) was calculated to 0.0187 Pa (mean of three determinations).

Other supporting data from various authoritative databases, also estimated the vapour pressure of 3-aminophenol as 1.273229 Pa (0.00955 mmHg) at 25°C and 0.24798 Pa (0.00186 mmHg) at 25°C.

Partition coefficient:

Various experimental studies from have been reviewed to determine octanol water partition coefficient of test chemical 3-aminophenol.

 

The first study was experimental report (2005) in this the purpose of the study was to determine the partition coefficient log Pow value of the test chemical by the shake-flask method (following guideline OECD 117). The partition coefficient log Pow value of the test chemical is determined to be 0.183 at 20 degree Celsius at the pH of 7.5.

 

Next study was also experimental study report (2012) in this study the partition coefficient (Log Pow) of test chemical 3-aminophenol  was determined  to be 0.22 dimensionless at 25°C  temperature and neutral pH 6.99.  

 

Further, other supporting data from another experimental study, reliable handbooks, various authoritative databases and publications, also determined the octanol water partition coefficient of 3-aminophenol as 0.21, 0.15, 0.16, 0.17 dimensionless.

 

Last study was reviewed from journal Quantitative Structure-Activity Relationship (1983) in this study the octanol water partition coefficient of test chemical 3-aminophenol was determined by using shake flask method. First of all the extinction coefficient for the test chemical in water was determined at a peak or shoulder in the UV spectrum above 220 nm. At least 4 samples with a concentration range of minimum 10-fold were prepared and partitioned between 1-octanol and water. 10 mg of the test chemical added in 2 ml/10 ml 1-octanol/water then to separate the phases the samples were thereafter centrifuged for 90 minutes at 2000 rpm. Part of the water layer was transferred to a UV cell and the absorbance measured with 1-octanol saturated water in the reference cell. The concentration of the compound in the 1-octanol layer was determined by subtraction. The partition coefficient (Log Pow) of test chemical 3-aminophenol was determined to be 0.17 dimensionless.  By considering Log pow value it can be concluded that test chemical 3-aminophenol is hydrophilic in nature.

 

By considering results of all the studies mentioned above it can be concluded that the octanol water partition coefficient (log pow) of test chemical 3-aminophenol (CAS no. 591-27-5) is in range from 0.15 to 0.22 dimensionless. By considering range Log pow value it can be concluded that test chemical 3-aminophenol is hydrophilic in nature which is also supported by high water solubility of test chemical 3-aminophenol.

Water solubility:

The solubility in water of the test item was determined according to the OECD 105 guideline and GLP. The water solubility was first evaluated in a preliminary test indicating a solubility value above 10 mg/L. Hence the final determination was undertaken using the flask method and HPLC/UV as analytical method. The water solubility of the test item was found to be 20100.0 mg/L (20.1 g/L) at 20°C using the flask method. The resulting saturated solutions were acid and colorless.

Other supporting data from another experimental study, reliable handbooks, various authoritative databases and publications, also determined the water solubility of 3-aminophenol as 29900 mg/L at 35°C, 26000 mg/L at 20°C, 25000 mg/L at 20°C, 27000 mg/L at 20°C, 26300 mg/L at 20°C respectively.

Hence on the basis of obtained values the 3-aminophenol is considered to be very soluble in water.

Surface tension:

In accordance with column 2 of Annex VII, surface activity is not expected and neither is surface activity a desired property of the chemical. Thus for 3-aminophenol,  this endpoint was considered for waiver.

Flash point:

The study does not need to be conducted because the flash point is only relevant to liquids and low melting point solids.

Auto flammability:

Determination of the Relative Self-Ignition Temperature of m-Aminophenol was made following EU A16 method and according to GLP. Using a linear increase in temperature of about 0.5°C/min up to about 400°C, the test item m-Aminophenol showed no self-ignition. In conclusion, the test item m-Aminophenol is considered not to be auto-flammable, according to the criteria as described in the guideline.

Flammability:

Determination of the Flammability of m-Aminophenol was made following EU A10 method and according to GLP. The test item m-Aminophenol was used in its initial form. The test item m-Aminophenol burned with flame which extinguished before smouldering along 200 mm of the powder rope. Based on this no further testing of the burning rate was required and test item m-Aminophenol is considered not to be flammable.

Explosiveness:

The study does not need to be conducted because there are no chemical groups present in the molecule which are associated with explosive properties.

Oxidising properties:

The study does not need to be conducted because there are no chemical groups present in the molecule which are associated with oxidizing properties and hence the classification procedure does not need to be applied.

pH:

Based on available data from authoritative database Gestis, the pH value of 10 g/L solution of 3-aminophenol is observed to be 6.8 at 20°C. Hence the substance is said to be near to neutral in nature.

Other supporting data from experimental report, also detemined the pH value of 1% solution of 3-aminophenol as 7.06 at 30°C. Hence 1% solution of the substance is said to be neutral in nature.

Dissociation constant:

The test item 3-aminophenol shows dissociation properties. The pKa values were found to be in the range of 4.37-5.25 for the forms +HBAH/BAH and in the range of 9.815-10.2 for the forms BAH/BA-.

Other supporting data from authoritative databases also stated, the 3-Aminophenol has both amine and hydroxy functional groups; the pKa values for these groups are 4.37 and 9.815, respectively.

Viscosity:

As per column 2 of Annex IX of the REACH regulation's, viscosity is an inherent property of a liquid substance of absorbing a stress during deformation which depends on the rate of the deformation. Since viscosity is an inherent property of liquids, this study need not to be conducted because 3-aminophenol is a solid substance as mentioned in section 4.1 of this dossier.