Phenethyl valerate

Endpoint summary

Description of key information

Stability:

Hydrolysis:

The hydrolysis half life at different pH and rate constant of test chemical 2-phenylethyl pentanoate (CAS No. 7460-74-4) was estimated by EPI  Suite (HydroWin). The Half life estimated at pH 7 was 2.842 years and at pH 8 was 103.820 days at temperature 25 oC. The rate Constant at pH > 8 was 7.727E-002 L/Mol/Sec  at 25 oC. Since, half life of hydrolysis of chemical 2-phenylethyl pentanoate is more than 10 days it shows negligible hydrolysis in water.

Biodegradation:

Biodegradation in water:

Biodegradability of test chemical 2-phenylethyl pentanoate was predicted by using OECD QSAR tool box v3.4 with log Kow as primary descriptor. The target chemical 2-phenylethyl pentanoate undergoes 93.166 % degradation by considering BOD as parameter and Microorganisms as inoculum in 28 days. Based on percent degradation value it is concluded that this test chemical is readily biodegradable.

Biodegradation in water and sediments:

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound 2-phenylethyl pentanoate(CAS No. 7460 -74 -4). If released in to the environment, 23.9 % of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of test chemical in water is estimated to be15 days (360 hrs). The half-life (15 days estimated by EPI suite) indicates that the chemical is not persistent in water and the exposure risk to aquatic animals is low whereas the half-life period of test chemical 2-phenylethyl pentanoate in sediment is estimated to be135 days (3240 hrs). However, as the percentage release of test chemical into the sediment is less than 2 % (i.e, reported as 1.08 %), indicates that test chemical 2-phenylethyl pentanoate is not persistent in sediment.

Biodegradation in soil:

The half-life period of test chemical 2-phenylethyl pentanoate (CAS No. 7460 -74 -4) in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database (EPI suite, 2017). If released into the environment, 73.2 % of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of test chemical 2-phenylethyl pentanoate in soil is estimated to be 30 days (720 hrs). Based on this half-life value of test chemical 2-phenylethyl pentanoate, it is concluded that the chemical is not persistent in the soil environment and the exposure risk to soil dwelling animals is low.

Bioaccumulation:

Bioaccumulation: aquatic/sediments :

Using BCFBAF Program (v3.00) model of EPI suite (2017) the estimated bio concentration factor (BCF) for 2-phenylethyl pentanoate (CAS No. 7460-74-4) is 216.8 L/kg wet-wt at 25 deg. c which does not exceed the bioconcentration threshold of 2000. Therefore it is concluded that test chemical 2-phenylethyl pentanoate is non bioaccumulative in food chain.

Transport and distribution:

Adsorption/desorption:

The Soil Adsorption Coefficient i.e. Koc value of test chemical 2-phenylethyl pentanoate (CAS No. 7460-74-4) was estimated using EPI suite KOCWIN Program (v2.00) as 1324 L/kg (log Koc= 3.1217) by means of MCI method at 25 deg. C.  This log Koc value indicates that test chemical 2-phenylethyl pentanoate has moderate sorption to soil and therefore have slow migration potential to ground water.

Additional information

Stability:

Hydrolysis:

Results of predicted data study for target chemical 2-phenylethyl pentanoate (CAS No. 7460-74-4) and experimental studies for its read across chemical for hydrolysis endpoint are summarized below.

The hydrolysis half life at different pH and rate constant of test chemical 2-phenylethyl pentanoate (CAS No. 7460-74-4) was estimated by EPI Suite (HydroWin). The Half life estimated at pH 7 was 2.842 years and at pH 8 was 103.820 days at temperature 25 oC. The rate Constant at pH > 8 was 7.727E-002 L/Mol/Sec at 25 oC. Since, half life of hydrolysis of chemical 2-phenylethyl pentanoate is more than 10 days it shows negligible hydrolysis in water.

 

In a supporting weight of evidence study for read across chemical from authoritative database ( HSDB, 2017) the half-life of the read across chemical benzyl acetate (CAS no. 140-11-4) was determined using an estimated pseudo-first order hydrolysis rate constant of 0.00000021/sec at a temperature of 25°C and pH 7.0, respectively. The half-life of benzyl acetate was determined to be 38 days at pH 7. Based on the half-life values, it is concluded that the read across chemical benzyl acetate is not hydrolysable

 

In another supporting weight of evidence study from same source as mentioned above the half-life and base catalyzed second order hydrolysis rate constant was determined using a structure estimation method for read across chemical 2-phenylethyl propanoate (CAS no. 122-70-3). The second order hydrolysis rate constant of 2-phenylethyl propanoate was determined to be 0.13 L/mol-sec with corresponding half-lives of 1.7 yrs and 63 days at pH 7 and 8, respectively. Based on the half-life values, it is concluded that the chemical 2-phenylethyl propanoate is not hydrolysable.

 

On the basis of results of all above mentioned studies it is concluded that test chemical 2-phenylethyl pentanoate (CAS No. 7460-74-4) is not hydrolysable.

Biodegradation:

Biodegradation in water:

Predicted data for the target compound 2-phenylethyl pentanoate and supporting weight of evidence studies for its read across substance were reviewed for the biodegradation end point which are summarized as below:

Biodegradability of test chemical 2-phenylethyl pentanoate was predicted by using OECD QSAR tool box v3.4 with log Kow as primary descriptor. The target chemical 2-phenylethyl pentanoate undergoes 93.166 % degradation by considering BOD as parameter and Microorganisms as inoculum in 28 days. Based on percent degradation value it is concluded that this test chemical is readily biodegradable.

 

Another prediction was done by using Estimation Programs Interface Suite (EPI suite, 2017)to determine the biodegradation potential of the test compound 2-phenylethyl pentanoate (CAS no. 7460 -74 -4) in the presence of mixed populations of environmental microorganisms. The biodegradability of the substance was calculated using seven different models such as Linear Model, Non-Linear Model, Ultimate Biodegradation Timeframe, Primary Biodegradation Timeframe, MITI Linear Model, MITI Non-Linear Model and Anaerobic Model (called as Biowin 1-7, respectively) of the BIOWIN v4.10 software. The results indicate that chemical 2-phenylethyl pentanoate is expected to be readily biodegradable.

 

In a supporting weight of evidence study for read across chemical benzyl acetate from Chemophere journal the biodegradation study was conducted for 28 days(4 weeks) for evaluating the percentage biodegradability of the test substance using the OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test) and Other guideline: New Biodegradability Test developed. The Sturm method was used in conjunction to validate the results of the new method.

The test was performed under aerobic conditions using activated sludge as an inoculum with conc. of 30 mg/l and initial test substance conc. is 10 mg/l (ranges from 2 – 10 mg/l). The read across substance in a dilute mineral salts solution is incubated in sealed vessels with appropriate micro-organisms for a period of up to 28 days. Controls containing the 0.5 to 10% inoculum concentration, without read across chemical are also prepared.

A vessel is removed from the shaker as required, a sample of the headspace gas withdrawn using a gas syringe and the concentration of carbon dioxide determined. The seal is then broken and the concentration of dissolved inorganic carbon (DIC) in the solution is measured immediately, Similar determinations are made for a control vessel which does not contain the read across substance. The difference in the total inorganic carbon found in the test and control vessels allows the quantity of carbon dioxide produced from the test compound to be ascertained.

The determination of carbon dioxide in both gaseous and aqueous samples was performed using a modified Ionics 555 TC-T°C Analyser. Carbon dioxide is released from aqueous samples of carbonate/bicarbonate by direct injection using a 0-200 µl Hamilton constant rate syringe onto an inert support loaded with phosphoric acid. The temperature in the reaction chamber is controlled at 150°C and pure nitrogen is used as the carrier gas. The detection system is a high sensitivity non-dispersive infra-red analyser. Gaseous samples are injected using a good quality gastight syringe.

A preliminary study was conducted using 2 mg/L of test substance conc. The percentage biodegradation of read across substance was determined to be 100.9% with standard deviation of 2.5 and 95% confidence interval of 96.9 – 104.9. Thus, the read across substance benzyl acetate was determined to be readily biodegradable.

 

 

In another weight of evidence study for read across chemical 2 -phenylethyl propanoate from Pest management Science journal ( 2008) the Biodegradation experiment was conducted for 30 days for evaluating the percentage biodegradability of read across substance 2 -phenylethyl propanoate. Pond water was used as a test inoculum collected from the Iowa State University Horticulture Farm pond (Ames, IA, USA). Initial test substance conc. used for the study was 10μg/g. The pH of the water was 7.3, the alkalinity was 91 mg/ml, and the total hardness was 182 mg/ml. Pond water (100 ml) was kept in French square bottles and spiked with 3H-PEP in 300 μl of acetone carrier solvent to result in a concentration of 10 μg/ml. The samples were incubated in dark and in light separately, and were maintained at a constant temperature of 25 ± 2°C throughout the study in the environmental chamber. Aluminum foil wrapping was used to prevent “dark” incubations from having exposure to light. Samples were taken at days 0, 0.25, 0.5, 1, 3, 7, 14, 21 and 30 post-treatment. Quantitative analysis of PEP was performed using a Hewlett-Packard (Palo Alto, CA, USA) series 1100 HPLC system with a quaternary pump, an autosampler, a thermostatted column compartment, and a Spectroflow 757 absorbance detector (ABI Analytical, Kratos Division, Ramsey, NJ, USA). Data were collected and analyzed using HP Chemstation system software (REV. A.04.01). An Alltech Adsorbosphere® (Deerfield, IL, USA) C18 column (4.6×250 mm, 5-μm particle size) was used. Detection was conducted at 270 nm with a flow rate of 1.0 ml/min at room temperature. The mobile phase was methanol/distilled water (70:30, v/v).Dissipation rates of PEP were calculated using first-order open models. A student’s-test was used to compare dissipation rates of PEP in light and in dark from the water dissipation studies. Dissipation of PEP in water was very rapid with a DT 50 of 5 days. Volatility loss was negligible in one month with mass balance from 96% to 100%. The primary degradation product was 2-phenylethanol, which was produced from ester hydrolysis of phenethyl propionate; another degradation product was 2-(4-hydroxyphenyl) ethanol, which was probably a biotransformation product of 2-phenylethanol in microbes. The percentage degradation of read across substance 2-phenylethyl propanoate was determined to be 50% in 5 days. Thus, based on percentage degradation, 2-phenylethyl propanoate is considered to be readily biodegradable in nature.

 

On the basis of results of above mentioned studies for target chemical 2-phenylethyl pentanoate (CAS No. 7460-74-4) (from OECD QSAR tool box v3.4 and EPI suite) and supporting weight of evidence study (from chemosphere and Pest management Science journal). It is concluded that the test chemical 2-phenylethyl pentanoat ecan be expected to be readily biodegradable.

Biodegradation in water and sediments:

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound 2-phenylethyl pentanoate (CAS No. 7460 -74 -4). If released in to the environment, 23.9 % of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of test chemical in water is estimated to be15 days (360 hrs). The half-life (15 days estimated by EPI suite) indicates that the chemical is not persistent in water and the exposure risk to aquatic animals is low whereas the half-life period of test chemical 2-phenylethyl pentanoate in sediment is estimated to be135 days (3240 hrs). However, as the percentage release of test chemical into the sediment is less than 2 % (i.e, reported as 1.08 %), indicates that test chemical 2-phenylethyl pentanoate is not persistent in sediment.

Biodegradation in soil:

The half-life period of test chemical 2-phenylethyl pentanoate (CAS No. 7460-74-4) in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database (EPI suite, 2017). If released into the environment, 73.2 % of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of test chemical 2-phenylethyl pentanoate in soil is estimated to be 30 days (720 hrs). Based on this half-life value of test chemical 2-phenylethyl pentanoate, it is concluded that the chemical is not persistent in the soil environment and the exposure risk to soil dwelling animals is low.

Bioaccumulation:

Bioaccumulation: aquatic/sediments :

Various predicted data for the target compound 2-phenylethyl pentanoate (CAS No. 7460-74-4) and supporting weight of evidence study for its read across chemical were reviewed for the bioaccumulation end point which are summarized as below:

First predicted data study was done by using BCFBAF Program (v3.00) model of EPI suite (2017) the estimated bio concentration factor (BCF) for 2-phenylethyl pentanoate (CAS No. 7460-74-4) is 216.8 L/kg wet-wt at 25 deg. c .

 

Second predicted data study was done by using Bio-concentration Factor (v12.1.0.50374) module of (ACD (Advanced Chemistry Development)/I-Lab predictive module, 2017) and Bio-concentration Factor  at range pH 1-14  of the chemical 2-phenylethyl pentanoate (CAS no.7460 -74 -4) estimated to be 535 dimensionless. This value indicates that the chemical 2-phenylethyl pentanoate is non-bioaccumulative in aquatic organisms.

Another bioconcentration factor (BCF) value was estimated by using Sci Finder database (American Chemical Society (ACS), 2017 at pH 1-10 and temperature 25 °C. The Bioconcentration factor (BCF) of test substance 2-phenylethyl pentanoate at pH 1-10 and temperature 25 °C was estimated to be 477 dimensionless. This BCF value at pH 1 -10 and temperature 25 °C suggests that the test chemical 2-phenylethyl pentanoate is non bioaccumulative in aquatic organisms.

 

Next study was done by using Chemspider-ACD/Phychem suite prediction model of Royal Society of Chemistry (2017)at pH 5.5 and pH 7.4. The Bioconcentration factor (BCF) of test substance 2-phenylethyl pentanoate at pH 5.5 and pH 7.4 was estimated to be 400.59 dimensionless. This BCF value suggests that the test chemical 2-phenylethyl pentanoate is non bioaccumulative in aquatic organisms.

 

Further, from CompTox Chemistry Dashboard using OPERA (OPEn (quantitative) structure-activity Relationship Application)  V 1.02 model in which calculation based on PaDEL descriptors (calculate molecular descriptors and fingerprints of chemical)  the bioaccumulation i.e BCF for test substance 2-phenylethyl pentanoate (CAS no.7460 -74 -4) was estimated to be 63.1 dimensionless it is based on the 5 OECD principles. Thus based on the result it is concluded that the test substance 2-phenylethyl pentanoate is non-bioaccumulative in nature.

 

In a supporting weight of evidence study the bioaccumulation test was conducted for estimating the BCF (bioaccumulation factor) value of read across chemical Acetic acid, phenylmethyl (CAS no. 140-11-4). The bioaccumulation factor (BCF) value was calculated using a log Kow of 1.96 and a regression derived equation. The BCF (bioaccumulation factor) value of Acetic acid, phenylmethyl was determined to be 18 dimensionless, which does not exceed the bioconcentration threshold of 2000, indicating that the chemical Acetic acid, phenylmethyl is considered to be non-accumulative in aquatic organisms.

Similarly in another supporting weight of evidence study the bioaccumulation factor (BCF) value was calculated using an estimated log Kow of 3.06 and a regression derived equation for read across chemical 2-phenylethyl propanoate (CAS no. 122-70-3). The BCF value of 2-phenylethyl propanoate was determined to be 46 dimensionless, which does not exceed the bioconcentration threshold of 2000, indicating that the chemical 2-phenylethyl propanoate is non-accumulative in aquatic organisms.

 

On the basis of above results for target chemical 2-phenylethyl pentanoate (CAS no.7460-74-4) (from EPI suite, ACD labs, Sci Finder database, Chemspider and CompTox Chemistry Dashboard 2017) and for its read across chemicals (From HSDB) it can be concluded that the BCF value of test substance 2-phenylethyl pentanoate ranges from 63.1 to 535 dimensionless which does not exceed the bioconcentration threshold of 2000, indicating that the chemical 2-phenylethyl pentanoate is expected to be nonbioaccumulative in the food chain.

Transport and distribution:

Adsorption/desorption:

Various predicted data for the target compound of 2-phenylethyl pentanoate (CAS No. 7460-74-4) and supporting weight of evidence study for its read across chemical were reviewed for the Adsorption end point which are summarized as below.

In first weight of evidence study the Soil Adsorption Coefficient i.e. Koc value of test chemical 2-phenylethyl pentanoate (CAS No. 7460-74-4) was estimated using EPI suite KOCWIN Program (v2.00) as 1324 L/kg (log Koc= 3.1217) by means of MCI method at 25 deg. C.  This log Koc value indicates that test chemical 2-phenylethyl pentanoate has moderate sorption to soil and therefore have slow migration potential to ground water.

In another weight of evidence study the Soil Adsorption Coefficient i.e Koc value of test substance 2-phenylethyl pentanoate (CAS no. 7460 -74 -4) was estimated using Adsorption Coefficient module (v12.1.0.50374) of(ACD (Advanced Chemistry Development)/I-Lab predictive module, 2017)program as Koc 3125 dimensionless (log Koc= 3.4948). This log Koc value indicates that the test substance 2-phenylethyl pentanoate has a strong sorption to soil and therefore have negligible to slow migration potential to groundwater.

 

Next prediction done by using Sci Finder database of American Chemical Society (ACS, 2017) the soil adsorption co-efficient i.e., Koc value of test chemical 2-phenylethyl pentanoate was estimated to be 2880.0 dimensionless (log Koc = 3.4593) at pH 1-10 at temperature 25 deg.c. this log Koc value suggests that this test chemical has strong sorption to soil therefore have negligible to slow migration potential to ground water.

 

Similarly, by using Chemspider-ACD/Phy chem suite the soil adsorption co-efficient i.e., Koc value of test substance 2-phenylethyl pentanoate was estimated to be 2538.74 dimensionless (og Koc= 3.4044) at pH 5.5 and 7.4 and temperature 25 deg.C This Koc value at different pH indicates that the chemical 2-phenylethyl pentanoate has strong sorption to soil and sediments therefore have negligible to slow migration potential to ground water.

 

Supporting weight of evidence study has done from authoritative database (HSDB, 2017) for read across chemical 2-phenylethyl propanoate. The adsorption coefficient (Koc) value was calculated using a structure estimation method based on molecular connectivity indices. The adsorption coefficient (Koc) value of 2-phenylethyl propanoate was determined to be 476 (Log Koc = 2.677). This Koc value indicates that the read across substance 2-phenylethyl propanoate has moderate sorption to soil and sediment and therefore have slow migration to ground water.

 

On the basis of above results for target chemical 2-phenylethyl pentanoate (CAS No. 7460-74-4) (from EPI suite, ACD labs, Sci Finder database and Chemspider 2017) and for its read across chemicals (From authoritative database HSDB) it can be concluded that the log Koc value of test substance 2-phenylethyl pentanoate ranges from 3.1217 to 3.4948 indicating that the chemical 2-phenylethyl pentanoate has moderate to strong sorption to soil and sediment and therefore have negligible to slow migration potential to ground water.