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Physical & Chemical properties

Vapour pressure

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Administrative data

Endpoint:
vapour pressure
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2020
Reliability:
2 (reliable with restrictions)
Cross-reference
Reason / purpose for cross-reference:
read-across source
Reference
Endpoint:
melting point/freezing point
Remarks:
melting point
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2020
Reliability:
1 (reliable without restriction)
Qualifier:
according to guideline
Guideline:
OECD Guideline 102 (Melting point / Melting Range)
GLP compliance:
not specified
Type of method:
thermal analysis
Key result
Decomposition:
yes
Decomp. temp.:
ca. 125 - ca. 400 °C
Remarks on result:
other: no determation of melting point possible. The substance decomposes.
Conclusions:
L-arginine phosphate monohydrate has been characterized by thermal analysis as advised in OECD Guideline 102, point 8, Table 1, aiming to determine its melting point and facilitate calculation of vapour pressure. The presented results clearly demonstrate that L-arginine phosphate monohydrate decomposes in three distinct stages between approximately 125 °C – 400 °C (see Figure 1 and Figure 2 in the report) rather than display specific melting points. Hence, a melting point cannot be determined due to decomposition.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2020
Report date:
2020

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 104 (Vapour Pressure Curve)
Deviations:
yes
Remarks:
expert judgement and read-across from melting point property
GLP compliance:
not specified
Type of method:
other: thermal analyses

Test material

Constituent 1
Chemical structure
Reference substance name:
L-arginine phosphate
EC Number:
949-986-2
Cas Number:
49720-39-0
Molecular formula:
C6H19N4O7P
IUPAC Name:
L-arginine phosphate
Test material form:
solid: crystalline
Remarks:
particulate/powder

Results and discussion

Vapour pressure
Key result
Temp.:
ca. 25 °C
Vapour pressure:
<= 0 mm Hg
Remarks on result:
not determinable because of methodological limitations
Remarks:
decomposition at 125-400 Celcius. Expected vapour pressure.
Transition / decomposition
Key result
Transition / decomposition:
yes
Remarks:
decomposition at 125-400 Celcius

Applicant's summary and conclusion

Conclusions:
The high temperature and energy required for decomposition of the compound and the lack of a mass loss prior to this decomposition suggests that L-arginine phosphate monohydrate displays similar properties as the closely related compounds L-arginine (CAS No. 74-79-3) and L-arginine·HCl (CAS No. 1119-34-2), reported as ≤ 0 mm Hg at 25 °C. The vapour pressure for L-arginine phosphate monohydrate can therefore be expected to be ≤ 0 mm Hg at 25°C.
Executive summary:

L-arginine phosphate monohydrate has been characterized by thermal analysis as advised in OECD Guideline 102, point 8, Table 1, aiming to determine its melting point and facilitate calculation of vapour pressure. The presented results clearly demonstrate that L-arginine phosphate monohydrate decomposes in three distinct stages between approximately 125 °C – 400 °C (see Figure 1 and Figure 2) rather than display specific melting points. Hence, a melting point cannot be determined due to decomposition.

Decomposition also means the crystalline compound has no vapour pressure that can be determined as mentioned in Guideline 104, point 3. The high temperature and energy required for decomposition of the compound and the lack of a mass loss prior to this decomposition suggests that L-arginine phosphate monohydrate displays similar properties as the closely related compounds L-arginine (CAS No. 74-79-3) and L-arginine·HCl (CAS No. 1119-34-2), reported as ≤ 0 mm Hg at 25 °C. The vapour pressure for L-arginine phosphate monohydrate can therefore be expected to be ≤ 0 mm Hg at 25°C.