2-phosphonobutane-1,2,4-tricarboxylic acid

pH

Administrative data

Endpoint:

pH

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2008-11-10 to 2008-12-19

Reliability:

1 (reliable without restriction)

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to other study

Reference

Endpoint:

viscosity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2008-11-10 to 2008-12-19

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods

Qualifier:

according to guideline

Guideline:

OECD Test Guideline 114 (Viscosity of Liquids)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: DIN 53019

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

rotational viscometer (dynamic)

Key result

Temp.:

20°C

Parameter:

dynamic viscosity (in mPa s)

Value:

0.016

Temp.:

40°C

Parameter:

dynamic viscosity (in mPa s)

Value:

0.009

Temp.:

20°C

Parameter:

other: m2/s

Value:

0

Remarks on result:

other: The correct value of the kinematic viscosity at 20°C is 1.28 exp.-05 m2/s.

The kinematic viscosity at 40°C is 6.8 exp.-06 m2/s. An entry of this value was not possible (max. 5 decimal places are allowed and "exp. writing" is not possible.

Conclusions:

The determination of the dynamic viscosity was performed according to DIN 53019 (German industry norm) and OECD 114 using a rotary viscosimeter at 20°C and 40°C. The kinematic viscosity was calculated with the dynamic viscosity and the density at test temperature. The following results were obtained:
Dynamic viscosity at 20 °C: 1.63 E-02 Pa · s
Dynamic viscosity at 40 °C: 8.6 E-03 Pa · s
Kinematic viscosity at 20 °C: 1.28 E-05 m2/s
Kinematic viscosity at 40 °C: 6.8 E-06 m2/s

Executive summary:

The determination of the dynamic viscosity was performed according to DIN 53019 (German industry norm) and OECD 114 using a rotary viscosimeter at 20°C and 40°C. The kinematic viscosity was calculated with the dynamic viscosity and the density at test temperature. The following results were obtained for the 50.4% aqueous solution of2-phosphonobutane-1,2,4-tricarboxylic acid:

Dynamic viscosity at 20 °C: 1.63 E-02 Pa · s

Dynamic viscosity at 40 °C: 8.6 E-03 Pa · s

Kinematic viscosity at 20 °C: 1.28 E-05 m2/s

Kinematic viscosity at 40 °C: 6.8 E-06 m2/s

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Reference

Endpoint:

dissociation constant

Type of information:

calculation (if not (Q)SAR)

Adequacy of study:

key study

Study period:

2009

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

accepted calculation method

Reason / purpose for cross-reference:

reference to other study

Principles of method if other than guideline:

No experimental determination but calculation of pKa.

GLP compliance:

no

Dissociating properties:

yes

No.:

#1

pKa:

>= 8.09 - <= 9.09

Temp.:

20 °C

Remarks on result:

other: pKa (HL/H+L)

No.:

#2

pKa:

>= 4.85 - <= 5.04

Temp.:

20 °C

Remarks on result:

other: pKa (H2L/H+HL)

No.:

#3

pKa:

>= 4.34 - <= 4.54

Temp.:

20 °C

Remarks on result:

other: pKa (H3L/H+H2L)

No.:

#4

pKa:

>= 3.78 - <= 4.2

Temp.:

20 °C

Remarks on result:

other: pKa (H4L/H+H3L)

No.:

#5

pKa:

>= 0.66 - <= 1.5

Temp.:

20 °C

Remarks on result:

other: pKa (H5L/H+H4L)

Statistical factors: +/-0.30

Conclusions:

In total, 2-phosphonobutane-1,2,4-tricarboxylic acid can release 5 protons step by step. Each release is described by one equilibrium constant (pKa). Depending on the value, the acid dissociation constants (pKa values) indicate strong (#5), medium strong (#4, #3, #2) and weak (#1) acids.
The pKa values indicate neither very strong nor very weak acids.

Executive summary:

The calculation of the dissociation constants of 2-phosphonobutane-1,2,4-tricarboxylic acid in water was performed by software ACD ChemSketch ACD/Labs 7.00 Release, Product Version 7.05. Usually the resulting dissociation constants are calculated for 20°C.

2-phosphonobutane-1,2,4-tricarboxylic acid in water can release 5 protons step by step.

Each release is described by one equilibrium reaction or equilibrium constant (pKa):

H5L = H+H4L (pKa = 1.08 ± 0.42)

H4L = H+H3L (pKa = 3.99 ± 0.21)

H3L = H+H2L (pKa = 4.44 ± 0.10)

H2L = H+HL (pKa = 4.99 ± 0.14)

HL = H+L (pKa = 8.59 ± 0.50)

Depending on the pKa value, the acid dissociation constants indicate strong (pKs < 3.8), medium strong (pKs < 7.2) and weak (pKs < 16) acids.

The pKa values indicate neither very strong nor very weak acids.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2009

Report date:

2009

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: CIPAC MT 75.3

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

2-phosphonobutane-1,2,4-tricarboxylic acid

EC Number:

253-733-5

EC Name:

2-phosphonobutane-1,2,4-tricarboxylic acid

Cas Number:

37971-36-1

Molecular formula:

C7H11O9P

IUPAC Name:

2-phosphonobutane-1,2,4-tricarboxylic acid

Test material form:

liquid

Remarks:

aqueous solution of 2-Phosphonobutane-1,2,4-tricarboxylic acid

Details on test material:

- Name of test item: Bayhibit AM

Results and discussion

pH value

pH value 1

Key result

pH value:

1.9

Concentration:

1 other: %

Remarks on result:

other: equals 0.5% of active ingredient (PBTC); dilution was performed with demineralised water

pH value 2

Key result

pH value:

0

Concentration:

100 other: %

Remarks on result:

other: equals 50.4% of active ingredient (PBTC); here it was undiluted

Applicant's summary and conclusion

Conclusions:

The determination of the pH-value was performed according to CIPAC MT 75.3. The determination of the pH value was performed with a pH meter equipped with a calibrated single-rod glass electrode. The pH-value was determined of the 50.4% aqueous solution of 2-Phosphono-1,2,4-butanetricarboxylic acid (PBTC) and of a 1 % solution of this test item (equals 0.5% PBTC) in demineralised water. The following results were received:
pH-value (1% [equals 0.5% PBTC]): 1.9
pH-value (undiluted [equals 50.4% PBTC]): 0.0

Executive summary:

The determination of the pH-value was performed according to CIPAC MT 75.3. The determination of the pH value was performed with a pH meter equipped with a calibrated single-rod glass electrode. The pH-value was determined of the 50.4% aqueous solution of 2-Phosphono-1,2,4-butanetricarboxylic acid (PBTC) and of a 1 % solution of this test item (equals 0.5% PBTC) in demineralised water. The following results were received:

pH-value (1% [equals 0.5% PBTC]): 1.9

pH-value (undiluted [equals 50.4% PBTC]): 0.0