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Registration Dossier
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EC number: 246-805-2 | CAS number: 25306-75-6
Endpoint summary
Administrative data
Description of key information
Additional information
Transport and distribution
Adsorption / desorption
According to “ANNEX IX- STANDARD INFORMATION REQUIREMENTS FOR SUBSTANCES MANUFACTURED OR IMPORTED IN QUANTITIES OF 100 TONNES OR MORE , an adsorption study need not be conducted if:
— based on the physicochemical properties the substance can be expected to have a low potential for adsorption (e.g. the substance has a low octanol water partition coefficient), or
— the substance and its degradation products decompose rapidly.
The log of the adsorption coefficient (KOC) of Sodium isobutyl xanthate was estimated to be log KOC = 1.06 which is equal to a KOC value of 11.7 using the KOCWIN v2.00 QSAR method. This value indicates that Sodium isobutyl xanthate will be adsorbed by organic carbon in soil. Sodium isobutyl xanthate can be classified to be of very high mobility in soil according these results and does not have a high potential for adsorption to soil
Sodium isobutyl xanthate and xanthates in general adsorbs strongly to sulphide minerals but has less affinity for surfaces in general. The KOC value of 11.7 also suggest this conclusion.
The estimated Soil Adsorption Coefficient was 11.7 L/kg measured by calculation from EPI SuiteTM v4.1 Program. This is Exposure Assessment Tools and Models made from EPA (Environmental Protection Agency
SMILES : O(C(CC)C)C(S([Na]))=S
CHEM :
MOL FOR: C5 H9 O1 S2 Na1
MOL WT : 172.24
--------------------------- KOCWIN v2.00 Results ---------------------------
NOTE: METAL (Na, Li or K) HAS BEEN REMOVED TO ALLOW ESTIMATION via MCI!
Koc Estimate from MCI:
---------------------
First Order Molecular Connectivity Index ........... : 3.664
Non-Corrected Log Koc (0.5213 MCI + 0.60) .......... : 2.5098
Fragment Correction(s):
1 Thiocarbonyl (C=S) .................. : -0.5701
1 Ether, aliphatic (-C-O-C-) .......... : -0.8716
Corrected Log Koc .................................. : 1.0681
Estimated Koc: 11.7 L/kg <===========
Koc Estimate from Log Kow:
-------------------------
Log Kow (Kowwin estimate) ......................... : -1.33
Non-Corrected Log Koc (0.55313 logKow + 0.9251) .... : 0.1894
Fragment Correction(s):
1 Thiocarbonyl (C=S) .................. : 0.3004
1 Ether, aliphatic (-C-O-C-) .......... : -0.0906
Corrected Log Koc .................................. : 0.3993
Estimated Koc: 2.508 L/kg <===========
Henry's Law constant
The estimated Henrys Law Constant (25 deg C) measured by calculation from EPI SuiteTM v4.1, HENRYWIN v3.20 Program was 3.491E-016 atm-m3/mole (3.538E-011 Pa-m3/mole) , which is almost zero.
This is Exposure Assessment Tools and Models made from EPA (Environmental Protection Agency).
Distribution modelling.
Sodium isobutyl xanthate has no affinity to be in air and sediment. The direct emissions to soil and surface water are significant, therefore Sodium isobutyl xanthate will be almost exclusively be found in soil and surface water.
Mackay fugacity modelling (level 3) indicates that, taking into account degradation and using inflow parameters which are consistent with the known production tonnage of this substance in, fugacity coefficient indicates that environmental concentrations in water are predicted to be 5.84e-021 (atm), in air (atm) 2.03e-019and soil 2.64e-019 (atm) and sediment to be 5.3e-021 (atm).
These are negligible low levels. This can be considered a worse case prediction as it assumes all product is emitted with no emission control systems used.
Other distribution data
These results suggest for Sodium isobutyl xanthate that direct and indirect exposure from distribution in media is unlikely.
Based on low vapor pressure and low estimated log Pow, expected to partition to water and soil. Not expected to partition to air, sediments or biota.
Therefore testing for distribution in media does not need to be performed.
The estimated STP Fugacity Model and Volatilization From Water were measured by calculation from EPI SuiteTM v4.1 Program. This is Exposure Assessment Tools and Models made from EPA (Environmental Protection Agency) .
Volatilization From Water
=========================
Chemical Name: Carbonodithioic acid, o-(2-methylpropyl) ester, sodium salt
Molecular Weight : 172.24 g/mole
Water Solubility : 8.179E+005 ppm
Vapor Pressure : 1.26E-009 mm Hg
Henry's Law Constant: 3.49E-016 atm-m3/mole (calculated from VP/WS)
RIVER LAKE
--------- ---------
Water Depth (meters): 1 1
Wind Velocity (m/sec): 5 0.5
Current Velocity (m/sec): 1 0.05
HALF-LIFE (hours) : 2.201E+012 2.401E+013
HALF-LIFE (days ) : 9.17E+010 1E+012
HALF-LIFE (years) : 2.511E+008 2.739E+009
STP Fugacity Model: Predicted Fate in a Wastewater Treatment Facility
======================================================================
(using 10000 hr Bio P,A,S)
PROPERTIES OF: Carbonodithioic acid, o-(2-methylpropyl) ester, sodium salt
-------------
Molecular weight (g/mol) 172.24
Aqueous solubility (mg/l) 17900
Vapour pressure (Pa) 1.67986E-007
(atm) 1.65789E-012
(mm Hg) 1.26E-009
Henry 's law constant (Atm-m3/mol) 9132E-016
Air-water partition coefficient 1.42785E-014
Octanol-water partition coefficient (Kow) 0.0467735
Log Kow -1.33
Biomass to water partition coefficient 0.809355
Temperature [deg C] 25
Biodeg rate constants (h^-1),half life in biomass (h) and in 2000 mg/L MLSS (h):
-Primary tank 0.04 16.16 10000.00
-Aeration tank 0.04 16.16 10000.00
-Settling tank 0.04 16.16 10000.00
STP Overall Chemical Mass Balance:
---------------------------------
g/h mol/h percent
Influent 1.00E+001 5.8E-002 100.00
Primary sludge 2.50E-002 1.4E-004 0.25
Waste sludge 1.51E-001 8.7E-004 1.51
Primary volatilization 1.90E-013 1.1E-015 0.00
Settling volatilization 5.19E-013 3.0E-015 0.00
Aeration off gas 1.28E-012 7.4E-015 0.00
Primary biodegradation 1.76E-003 1.0E-005 0.02
Settling biodegradation 5.27E-004 3.1E-006 0.01
Aeration biodegradation 6.93E-003 4.0E-005 0.07
Final water effluent 9.82E+000 5.7E-002 98.15
Total removal 1.85E-001 1.1E-003 1.85
Total biodegradation 9.22E-003 5.4E-005 0.09
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