3-aminopropyltriethoxysilane

Other distribution data

Administrative data

Endpoint:

other distribution data

Adequacy of study:

supporting study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: The fugacity modeling was conducted using an accepted model. Measured and estimated data were both used for chemical-specific data required by the model.

Data source

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

1975

Reference 2

Reference Type:

study report

Title:

Unnamed

Year:

2001

Reference 3

Reference Type:

study report

Title:

Unnamed

Year:

1996

Reference 4

Reference Type:

secondary source

Title:

Material Safety Data Sheet. CAS No. 919-30-2

Author:

Union Carbide Chemicals and Plastics Company, Inc.

Year:

1992

Report date:

1992

Reference 5

Reference Type:

other: estimation software

Title:

Estimations Programs Interface (EPI) Suite™. (The EPI Suite™ and the individual models included within the software are owned and copyright protected by the U.S. Environmental Protection Agency.)

Author:

United States Environmental Protection Agency

Year:

2000

Materials and methods

Principles of method if other than guideline:

The EQC model (Mackay 1996) was used for all fugacity calculations as recommended by EPA.

Type of study:

other: Fugacity Model Level I, II and III

Media:

other: other

Test material

Test material information

Constituent 1

Reference substance name:

3-aminopropyltriethoxysilane

EC Number:

213-048-4

EC Name:

3-aminopropyltriethoxysilane

Cas Number:

919-30-2

Molecular formula:

C9H23NO3Si

IUPAC Name:

silane

Results and discussion

Any other information on results incl. tables

The EQC Level III model (USEPA, 2000) was used to evaluate
the fate, transport and distribution of this material
between environmental matrices, as recommended by EPA. 
Level III Fugacity modeling, using loading rates for Air,
Soil, and Water of 1000 kg/h for each media, shows the
following percent distribution: Air = 0.7%; Soil = 91.6%;
Water = 7.7 %; Sediment = 0.00 %. However, this material is
unlikely to be found in the environment as it is
hydrolytically unstable.     

Results from LEvel II modeling indiacte distribution to air, water and  soil of 0, 99.8 and .2%, respectively.

Table 1.  Physical and chemical properties of
3-aminopropyltriethoxysilane (CAS No. 919-30-2).

Molecular weight = 221
Data temperature (degrees C)= 25
Water solubility (g/m3)=7.6x-105 (Est.value Note1) (ref3)
Vapor pressure (Pa)= 2.0 (Extrapolated from
temperature-vapor pressure correlation Note2)
Log Kow        = 0.31  (Est. value Note3)
Melting point (°C)=  -70 (ref4)
Half-life in air (h)=2.4 (Est. value Note4)
Half-life in water (h)= 8.4 (Measured at pH 7.0, 25 °C)
(ref5)
Half-life in soil (h)=80 (Est. value Note5)
Half-life in sediment(h)=8.4 (Est. value Note5)

Note1   Water solubility of 3-aminopropyltriethoxysilane at 25 degrees C  was estimated using the SAR Model WSKOWWIN (version 1.40).  The model was  used as received from the EPA.

Note2   Vapor pressure of 3-aminopropyltriethoxysilane at 25 degrees C  was extrapolated from a temperature-vapor pressure relationship that was  developed using experimental data measured at temperatures ranging from  55-122 degrees C.

Note3   Log Kow of 3-aminopropyltriethoxysilane at 25 degrees C was  estimated using the SAR Model KOWWIN (version 1.66).  The model was used  as received from the EPA. 

Note4   The half-life in air of 3-aminopropyltriethoxysilane at 25  degrees C was estimated using the SAR Model APOWIN (version 1.90). 
The model was used as received from the EPA.

Note5   The overall half-life of 3-aminopropyltriethoxysilane in soil and  sediment were estimated as a function of the measured hydrolysis 
half-life and the estimated rate of biodegradation in water.
Biodegradation was estimated using the SAR Model BIOWIN (version 4.00),  as received from the EPA. The BIOWIN
result for ultimate biodegradation timeframe (2.7344;
"weeks-months") was converted to an estimated half-life in water (900  hours) using the EPA default conversion factors in EPI Suite.  
Biodegradation half-life in soil was assumed to be 2 times
longer than the BIOWIN estimate for water.  Biodegradation
half-life in sediment was assumed to be 9 times longer than the BIOWIN  estimate for water.  The half-life in sediment was assumed to be equal to  the measured hydrolysis half-life in water. Because of the decreased  activity of water in soil, the hydrolysis half-life in soil was 
assumed to be 10 times longer than the measured half-life in water.  


The measured hydrolysis half-life for
3-aminopropyltriethoxysilane at pH 7.0 is 8.4 hours at 25 deg C.  As  such, 3-aminopropyltriethoxysilane will not exist in the 1environment,  but will rapidly hydrolyze to ethanol and 3-aminopropylsilanetriol.  
The environmental fate, transport, and distribution of 
3-aminopropylsilanetriol were evaluated to provide a more 
realistic assessment of 3-aminopropyltriethoxysilane. 
Results from the simulation suggest that >99% of the total
steady-state mass of 3-aminopropylsilanetriol will reside in the water  and soil compartments, and will not be found in air or sediment. 
It is expected taht 65-85% of the 3-aminopropylsilanetriol
produced by the steady-state hydrolysis of 
3-aminopropyltriethoxysilane will degrade in about 20-40
days.

Air % (Fugacity Model Level I): 0
Water % (Fugacity Model Level I): 99.8
Soil % (Fugacity Model Level I): 0.2

Applicant's summary and conclusion

Conclusions:

If released directly to air,
about 40% of the steady-state emission is expected to
degrade in air, 50% expected to partition to and degrade in
soil, and 6% expected to partition to and degrade in water.
When released to soil, 90% of the steady-state emission is
expected to degrade in soil, and 10% expected to partition
to
and degrade in water. When released to water, essentially
100% will degrade in water. Advection from the local
environment is expected to be insignificant (£ 1% of the
steady-state emission) for all emission scenarios. Global
persistence of 3-aminopropyltriethoxysilane in the model
system was about 3 days when released directly to air,
about 5 days when released to soil, and about 0.5 days
when released to water. If released simultaneously to all
three compartments (i.e., air, water, and soil), essentially

100% of the steady-state emission degrades in about 3
days. Based on Level-III modeling, it is expected that
> 99% of the total steady-state mass of
3-aminopropyltriethoxysilane will reside in the water and
soil compartments and will not be found in air or sediment