Dibutyl hydrogen phosphate

Vapour pressure

Link to relevant study record(s)

Reference

Endpoint:

vapour pressure

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 104 (Vapour Pressure Curve)

Deviations:

not specified

Qualifier:

according to guideline

Guideline:

EU Method A.4 (Vapour Pressure)

Deviations:

not specified

GLP compliance:

no

Type of method:

other: Combination of "effusion method: by loss of weight or by trapping vaporisate" and "static method"

Key result

Temp.:

20 °C

Vapour pressure:

0 Pa

Remarks on result:

other: calculated from experimental values

Temp.:

25 °C

Vapour pressure:

0 Pa

Remarks on result:

other: calculated from experimental values

Temp.:

49.95 °C

Vapour pressure:

0.01 Pa

Remarks on result:

other: experimental result (Knudsen effusion method, average of two measurements)

Temp.:

50 °C

Vapour pressure:

0.01 Pa

Remarks on result:

other: calculated from experimental values

Temp.:

55 °C

Vapour pressure:

0.02 Pa

Remarks on result:

other: calculated from experimental values

Temp.:

59.95 °C

Vapour pressure:

0.045 Pa

Remarks on result:

other: experimental result (Knudsen effusion method, average of two measurements)

Temp.:

69.95 °C

Vapour pressure:

0.127 Pa

Remarks on result:

other: experimental result (Knudsen effusion method, average of two measurements)

Temp.:

90 °C

Vapour pressure:

1.3 Pa

Remarks on result:

other: experimental result (static method, average of three measurements)

Temp.:

110 °C

Vapour pressure:

8.54 Pa

Remarks on result:

other: experimental result (static method, average of three measurements)

Temp.:

129.2 °C

Vapour pressure:

46.37 Pa

Remarks on result:

other: experimental result (static method, average of three measurements)

Results obtained in the measurement of the vapor pressures of dibutyl hydrogen phosphate using the Knudsen effusion method.

 

T / °C = 49.95    t = 19h36m46s

Cell	m / mg	p / Pa
I	1.87	0.0100
IV	1.76	0.0093

  

T / °C = 59.95    t = 07h27m42s

Cell	m / mg	p / Pa
I	3.40	0.0485
IV	2.97	0.0418

  

T / °C = 69.95    t = 03h52m58s

Cell	m / mg	p / Pa
I	4.79	0.1333
IV	4.40	0.1207

  

T / °C = 79.90    t = 02h49m38s

Cell	m / mg	p / Pa
I	10.35	0.4012
IV	8.97	0.3428

  

 

Results obtained in the measurement of the vapor pressures of dibutyl hydrogen phosphate using the static method.

 

T / K	T / °C	p / Pa	p / mbar
90.00	363.15	1.30	0.013
99.40	372.55	3.18	0.0318
110.00	383.15	8.54	0.0854
119.30	392.45	18.47	0.1847
129.20	402.35	46.37	0.4637

 

 

Recommended vapor pressures for dibutyl hydrogen phosphate up to 240 °C, calculated from the application of the equation of Clarke and Glew to the results obtained in this work.

 

T / °C	T / K	p / Pa	p / mbar
-20	253.15	4.75E-08	4.75E-010
-15	258.15	1.45E-07	1.45E-09
-10	263.15	4.22E-07	4.22E-09
-5	268.15	1.18E-06	1.18E-08
0	273.15	3.16E-06	3.16E-08
5	278.15	8.17E-06	8.17E-08
10	283.15	2.04E-05	2.04E-07
15	288.15	4.91E-05	4.91E-07
20	293.15	1.15E-04	1.15E-06
25	298.15	2.59E-04	2.59E-06
30	303.15	5.70E-04	5.70E-06
35	308.15	1.22E-03	1.22E-05
40	313.15	2.54E-03	2.54E-05
45	318.15	5.17E-03	5.17E-05
50	323.15	1.03E-02	1.03E-04
55	328.15	1.99E-02	1.99E-04
60	333.15	3.78E-02	3.78E-04
65	338.15	7.04E-02	7.04E-04
70	343.15	1.28E-01	1.28E-03
75	348.15	2.30E-01	2.30E-03
80	353.15	4.05E-01	4.05E-03
85	358.15	7.00E-01	7.00E-03
90	363.15	1.19E+00	1.19E-02
95	368.15	1.99E+00	1.99E-02
100	373.15	3.28E+00	3.28E-02
105	378.15	5.34E+00	5.34E-02
110	383.15	8.55E+00	8.55E-02
115	388.15	1.35E+01	1.35E-01
120	393.15	2.11E+01	2.11E-01
125	398.15	3.26E+01	3.26E-01
130	403.15	4.96E+01	4.96E-01
135	408.15	7.48E+01	7.48E-01
140	413.15	1.11E+02	1.11E+00
145	418.15	1.64E+02	1.64E+00
150	423.15	2.40E+02	2.40E+00
155	428.15	3.46E+02	3.46E+00
160	433.15	4.96E+02	4.96E+00
165	438.15	7.04E+02	7.04E+00
170	443.15	9.89E+02	9.89E+00
175	448.15	1.38E+03	1.38E+01
180	453.15	1.91E+03	1.91E+01
185	458.15	2.62E+03	2.62E+01
190	463.15	3.56E+03	3.56E+01
195	468.15	4.81E+03	4.81E+01
200	473.15	6.46E+03	6.46E+01
205	478.15	8.60E+03	8.60E+01
210	483.15	1.14E+04	1.14E+02
215	488.15	1.50E+04	1.50E+02
220	493.15	1.96E+04	1.96E+02
225	498.15	2.54E+04	2.54E+02
230	503.15	3.28E+04	3.28E+02
235	508.15	4.21E+04	4.21E+02
240	513.15	5.37E+04	5.37E+02

 

Conclusions:

The vapor pressure of dibutyl hydrogen phosphate is 0.000115 Pa at 20 °C.

Executive summary:

The vapor pressure of dibutyl phosphate was measured using the Knudsen effusion method (mass-loss technique) and a static method suitable for very low vapor pressures, according to the guidelines OECD 104 / EU A.4.

The quality of both apparatus was previously verified with the measurement of well-known reference compounds. Experiments were performed at temperatures between 50 °C and 80 °C using the Knudsen effusion method, and between 80 °C and 130 °C using the static method.

Results were modeled with a thermodynamic equation, establishing the relation between the vapor pressure of the compound and temperature and allowing the knowledge of the vapor pressure at different temperatures.

Description of key information

The vapor pressure of dibutyl hydrogen phosphate is 0.000115 Pa at 20 °C.

Key value for chemical safety assessment

Vapour pressure:

0 Pa

at the temperature of:

20 °C

Additional information

The vapor pressure of dibutyl phosphate was measured using the Knudsen effusion method (mass-loss technique) and a static method suitable for very low vapor pressures, according to the guidelines OECD 104 / EU A.4.

Results were modeled with a thermodynamic equation, establishing the relation between the vapor pressure of the compound and temperature and allowing the knowledge of the vapor pressure at different temperatures.

The vapor pressure of dibutyl hydrogen phosphate can be calculated using the following truncated equation of Clarke and Glew.

ln(p) = exp({- (ΔG / θ) + ΔH * [(1 / θ) + (1 / T)] + ΔC * [(θ / T) - 1 + ln(T / θ)]} / R)

Where p is the vapour pressure in Pa, T is the temperature in Kelvin, ΔG is the Gibbs energy of vaporization at the reference temperature θ [-389.82 J/mol], ΔH is the enthalpy of vaporization at the reference temperature θ [114715 J/mol], ΔC is the difference between the heat capacity of the gas and the heat capacity of the liquid at the reference temperature θ [-60 J/(mol K)], θ is the reference temperature [362.72 K] and R is the gas constant [8.3144621 J/(mol K)].