Pyrocatechol

Particle size distribution (Granulometry)

Link to relevant study record(s)

Reference

Endpoint:

particle size distribution (granulometry)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The data was obtained using a standardised internal method specifically developped for the case of flakes. This procedure was highly adapted to catechol. Furthermore, the study report contains a high level of experimental details.

Qualifier:

no guideline followed

Principles of method if other than guideline:

Sieving analysis was performed on flakes. Fine fractions (particles < 100 µm) coming from sieving analysis were characterized by laser diffraction particle size analysis. A fragility test with attrition was then carried out on flakes with internal sieving method. The particle size distribution hence obtained was compared with the results of the sieving analysis realized without attrition of flakes.

GLP compliance:

no

Type of method:

sieving

Type of distribution:

volumetric distribution

Key result

Percentile:

D50

Mean:

113.1 µm

Remarks on result:

not measured/tested

Remarks:

No data available on the st. dev.

No.:

#1

Size:

< 100 µm

Distribution:

1.05 %

No.:

#1

Size:

> 100 - < 200 µm

Distribution:

2.05 %

No.:

#1

Size:

> 200 - < 500 µm

Distribution:

3.48 %

No.:

#1

Size:

> 500 - < 1 000 µm

Distribution:

3.09 %

No.:

#1

Size:

> 1 000 - < 5 000 µm

Distribution:

67.78 %

No.:

#1

Size:

> 5 000 µm

Distribution:

22.55 %

Digital camera pictures & Microscope pictures

Tan to brown flakes of catechol presented a great heterogeneity of sizes and shapes with most large flakes ranging from 0.5 to 3 cm. A lot of breakage parts of flakes were present. The finest particles around bigger flakes looked like boken larger objects.

Sieving Analysis on the passing fraction at 2,7mm

Average results for the five samples are presented below:

- 22.6% of the particles weight presented sizes > 5000 µm.

- A great quantity of flakes (67.8% weight) presented sizes in the range from 1000 and 5000 µm.

- 10% of the particles weight presented sizes < 1000 µm.

- 1.05% of the particles weight presented sizes <100 µm (see here after laser diffraction analysis Sympatec).

Laser diffraction particle size analysis performed on fine fraction (< 100 µm)

Measurements on the fine fraction (< 100 µm) coming from the sieving analysis gave the following results:
x₁₀= 60.5 µm               

x₅₀= 113.1 µm              

x₉₀= 197.0 µm                         

fines <100µm = 40.0%w/w

Particles < 1,8 µm : 0,5% in volume

Particles < 10 µm : 0,9% in volume

Fragility test:

Results obtained in fragility test with attrition are described below:

- The majority of the flakes (92.2% weight) were kept in their original size (>1000 µm).

- 4.6% of the particles weight were found in the range from 500 to 1000 µm.

- 2.46%of the particles weight were found in the range from 200 to 500 µm.

- 0.74 % of the particles weight were foud in the range from 100 to 200 µm.

- No particles were found in the range < 100 µm.

This implies that catechol flakes are not fragile; keeping their original size after attrition. Furthermore, attrition does not generate fines particles with size < 100 µm.

Conclusions:

The majority of catechol flakes (90.3% weight) presented sizes superior to 1000 µm. A very small quantity of flakes (1.05%) were found in the size range below 100 µm. Flakes subjected to attrition mainly kept their original size, and did not generate fine particles with size inferior to 100 µm.

Executive summary:

A standardised internal method specifically developped for the case of flakes was developped. It was applied to catechol flakes. Firstly, a sieving analysis was performed on flakes. The fine fraction (particles size < 100 µm) hence obtained was characterized using laser diffraction particle size analysis. A fragility test using attrition was also carried out to compared the granulometric results with and without attrition to assess the fragility of catechol flakes.

The first sieving analysis (without attrition) revealed that the majority of the flakes (90.3% weight) presented sizes superior to 1000 µm. A very small quantity (1.05%) were found in the size range below 100 µm. A laser diffraction analysis of this fine fraction gave D10, D50 and D90 equal to 60.5 µm, 113.1 µm and 197 µm, respectively. The fragility test showed that flakes subjected to attrition mainly kept their original size, and did not generate fine particles with size inferior to 100 µm.

Description of key information

The majority of the catechol flakes (90.3% weight) presented sizes superior to 1000 µm. A very small quantity (1.05%) were found in the size range below 100 µm. A laser diffraction analysis of this fine fraction gave D10, D50 and D90 equal to 60.5 µm, 113.1 µm and 197 µm, respectively. The fragility test showed that flakes subjected to attrition mainly kept their original size, and did not generate fine particles with size inferior to 100 µm. 

Additional information

An experimental study is available. It was performed according to a standardized internal method specifically developed for the case of flakes. As this procedure is highly adapted to catechol, this data was scored reliability 1 according to Klimisch and was selected as a key study.