Di-tert-dodecyl disulphide

Partition coefficient

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

partition coefficient

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: This QSAR result cannot be backed by an experimental value, given the very high logKow involved outside domain of applicability of current methods

Justification for type of information:

QSAR prediction: migrated from IUCLID 5.6

Principles of method if other than guideline:

The KOWWIN program and estimation methodology were developed at Syracuse Research Corporation.  A journal article by Meylan and Howard (1995) describes the program methodology. KOWWIN uses a "fragment constant" methodology to predict log P.  In a "fragment constant" method, a structure is divided into fragments (atom or larger functional groups) and coefficient values of each fragment or group are summed together to yield the log P estimate.   KOWWIN’s methodology is known as an Atom/Fragment Contribution (AFC) method.  Coefficients for individual fragments and groups were derived by multiple regression of 2447 reliably measured log P values.

Type of method:

other: QSAR

Partition coefficient type:

octanol-water

Type:

log Pow

Partition coefficient:

ca. 12.45

Temp.:

20

pH:

ca. 7

Remarks on result:

other: calculated

Log Kow(version 1.68 estimate): 12.46

SMILES : CCCCCCCCCC(C)(C)SSC(C)(C)CCCCCCCCC

CHEM : Polysulfides, di-tert-dodecyl

MOL FOR: C24 H50 S2

MOL WT : 402.79

-------+-----+--------------------------------------------+---------+--------

TYPE | NUM | LOGKOW FRAGMENT DESCRIPTION | COEFF | VALUE

-------+-----+--------------------------------------------+---------+--------

Frag | 6 | -CH3 [aliphatic carbon] | 0.5473 | 3.2838

Frag | 16 | -CH2- [aliphatic carbon] | 0.4911 | 7.8576

Frag | 1 | -SS- [disulfide] | 0.5497 | 0.5497

Frag | 2 | -tert Carbon [3 or more carbon attach] | 0.2676 | 0.5352

Const | | Equation Constant | | 0.2290

-------+-----+--------------------------------------------+---------+--------

NOTE | | An estimated coefficient (**) used |

-------+-----+--------------------------------------------+---------+--------

Log Kow = 12.4553

Conclusions:

logKow > 12

Executive summary:

KOWWIN calculates a logKow = 12.4553 for Disulfide, di-tert-dodecyl, with the default structure linked to the CAS number 27458 -90 -8. A more ramified structure gives close results.

Reference 2

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017-03-07 to 2017-03-28

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Key result

Type:

log Pow

Partition coefficient:

> 6.5

Temp.:

55 °C

pH:

7.5

The determination of the HPLC retention times of the test item and of the analytical reference items was made twice. A calibration curve (R² = 0.9959) was constructed from the retention time data of the dead time and analytical reference items.

The capacity factors (k') were calculated using the following equation: k_i’ = (tr – t0) / t0

where

k_i’ is the capacity factor of compound i

tr_i is the retention time of compound i

t₀ is the dead volume time

 

The partition coefficient of the test item was determined using the equation below with reference to the calibration: log Kow= m.log k’ + b

 where

k’is the capacity factor of the test item

m and b the coefficients of the calibration curve

Log₁₀Kow values of the reference standards are those quoted in Method 117 of the OECD Guidelines for Testing of Chemicals, 13 April 2004.

Conclusions:

The partition coefficient log Kow of the test item was experimentally measured in accordance with OECD testing 117 guideline with GLP compliance.
The partition coefficient log Kow of the test item is >6.5.

Executive summary:

The partition coefficient log Kow of the test item was experimentally measured in accordance with OECD testing 117 guideline with GLP compliance.

The partition coefficient log Kow of the test item is >6.5.

Description of key information

A study performed according to the HPLC method showed that the log Kow of all the constituents of the substance are all higher than 6. Gancet (2008) showed the same pattern with di-tert-dodecyl polysulfides which is used as a source read-across substance for other endpoints of the present dossier. The Log Pow of di-tert-dodecyl disulfide was estimated around 12.5 according to a validated QSAR.

Key value for chemical safety assessment

Log Kow (Log Pow):

12.5

at the temperature of:

20 °C