1,1'-(ethane-1,2-diyl)bis[pentabromobenzene]

Mode of degradation in actual use

Administrative data

Endpoint:

mode of degradation in actual use

Remarks:

This study addresses the concern expressed in the substance evaluation about formation of brominated dioxins and furans or other degradation products of concern during the life-cyle of EBP

Type of information:

experimental study

Remarks:

The report summarizes a number of experimental and literature studies.

Adequacy of study:

key study

Study period:

1992 to 2016

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Data source

Reference

Reference 1

Reference Type:

other company data

Title:

Unnamed

Year:

2019

Report date:

2019

Reference 2

Reference Type:

publication

Title:

Thermal decomposition of flame-retarded high-impact polystyrene

Author:

Jakab et al.

Year:

2003

Bibliographic source:

J Anal Appl Pyrolysis 68-69, 83-99.

Reference 3

Reference Type:

study report

Title:

Unnamed

Year:

1993

Reference 4

Reference Type:

publication

Title:

Defintive study of the determination of polybrominated dibenzo-p-dioxins and polybrominated dibenzofurans in decabromodiphenyloxide and tetrabromobisphenol-A

Author:

Ranken et al.

Year:

1994

Bibliographic source:

Bull. Soc. Chim. Belg. 103(5-6): 218-233

Reference 5

Reference Type:

other company data

Title:

Unnamed

Year:

2007

Reference 6

Reference Type:

other company data

Title:

Unnamed

Year:

1992

Report date:

1994

Reference 7

Reference Type:

study report

Title:

Unnamed

Year:

1995

Report date:

1995

Materials and methods

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

This report presents the available evidence on the presence or absence of polybrominated dibenzofurans and dibenzo-p-dioxins in EBP formulations and in polymer formulations before and after exposure to high temperatures recycling and incineration. The mechanisms of thermal degradation are also presented; this supports the conclusion that furans and dioxins are not formed.

Chapter 2 discusses the absence of the polybrominated dibenzofurans and dibenzo-p-dioxins in EBP and in EBP formulated with antimony trioxide.

Chapter 3 outlines the impurities of EBP present in various plastics as a flame retardant. These include high impact polystyrenes (HIPS) that are widely used for electrical appliances, electronic instruments and building materials. HIPS is a graft co-polymer of polystyrene and dispersed polybutadiene (PB) rubber.

Chapter 4 discusses the thermal degradation and incineration of EBP to polybrominated toluenes rather than polybrominated dibenzofurans and dibenzo-p-dioxins. The synergistic role of antimony trioxide is explained.

GLP compliance:

no

Type of study / information:

Information on possible degradation products at elevated temperatures.

Test material

Test material information

Results and discussion

Any other information on results incl. tables

This report summarises various internal reports for the analytical determination of polybrominated dibenzofurans (PBDFs) and dibenzo-p-dioxins (PBDDs) under various conditions by Albemarle and external contractors. These include elevated temperature conditions simulating incineration of flame retarded plastic materials and recycling cycles. These determinations were performed in the main to investigate compliance of polymers containing EBP and EBP plus antimony trioxide in typical concentrations with the German Dioxane Ordinance and EPA guidelines on determining the absence of brominated dioxins and furans during combustion processes. The reference chemicals were also chosen on this basis.

1. Overview

Concern has been expressed that polybrominated dibenzofurans (PBDFs) and polybrominated dibenzo-p-dioxins (PBDDs) may be present as impurities or degradation products in polymers containing1,1'-(ethane-1,2-diyl)bis[pentabromobenzene] (EBP) used as a flame retardant.

 It is very important to differentiate EBP from decabromodiphenyl ether (DecaBDPE, known as deca). Care is needed because the abbreviation DecaBDPE is used in some published sources as a synonym for EBP. Although the two brominated flame retardants appear similar, there are important differences in their thermal degradation. DecaDBPE formspolybrominated dibenzofurans (PBDFs) and polybrominated dibenzo-p-dioxins (PBDDs)upon combustion whereas EBP does not.

Jakab et al. (2003) stated that the EBP degrades when heated to about 600 deg. C, giving brominated toluenes by the scission of the aliphatic C-C bond of the ethyl group and H-uptake from the polymer. The main degradation product is penta bromo-toluene (Br5 -toluene). Therefore, no polybrominated dibenzo-p-dioxins are formed. This is supported by the observed thermal instability of EBP when undergoing gas chromatography. Hence, in analysis for Br9 and Br8, HPLC-MS has been preferred.

The importance of polybrominated dibenzofurans and polybrominated dibenzo-p-dioxins is emphasised by the introduction of the German Chemical Prohibition Ordnance (ChemVerbotsV) that prohibits substances, preparations or products that contain certain halogenated dibenzodioxins and dibenzofurans above certain limits on the German market. The Ordinance includes eight 2,3,7,8-substituted polybrominated dibenzodioxins (PBDDs) and dibenzofurans (PBDFs). Table 1-2 gives further details.

 

PBDD and PBDF containing products prohibited byGerman Chemical Prohibition Ordnance(ChemVerbotsV).

Any product containing more than 1 ppb of the sum of four congeners.
Group 1	2,3,7,8-tetrabromodibenzodioxin (TBDD)	2,3,7,8-TBDD
	2,3,7,8-tetrabromodibenzofuran (TBDF)	2,3,7,8-TBDF
	1,2,3,7,8-pentabromodibenzodioxin (PeBDD)	1,2,3,7,8-PeBDD
	2,3,4,7,8-pentabromodibenzofuran (PeBDF);	2,3,4,7,8-PeBDF
Or more than 5 ppb of the sum of eight congeners.
Group 1	2,3,7,8-tetrabromodibenzodioxin (TBDD)	2,3,7,8-TBDD
	2,3,7,8-tetrabromodibenzofuran (TBDF)	2,3,7,8-TBDF
	1,2,3,7,8-pentabromodibenzodioxin (PeBDD)	1,2,3,7,8-PeBDD
	2,3,4,7,8-pentabromodibenzofuran (PeBDF)	2,3,4,7,8-PeBDF
Group 2	1,2,3,7,8-pentabromodibenzofuran (PeBDF)
	1,2,3,4,7,8-hexabromodibenzodioxin (HxBDD)
	1,2,3,7,8,9-hexabromodibenzodioxin (HxBDD)
	1,2,3,6,7,8-hexabromodibenzodioxin (HxBDD).

 

This report presents the available evidence on the presence or absence of polybrominated dibenzofurans and dibenzo-p-dioxins in EBP formulations and in polymer formulations before and after exposure to high temperatures recycling and incineration. The mechanisms of thermal degradation are also presented; this supports the conclusion that furans and dioxins are not formed.

 

Chapter 2 discusses the absence of the polybrominated dibenzofurans and dibenzo-p-dioxins in EBP and in EBP formulated with antimony trioxide.

 

Chapter 3 outlines the impurities of EBP present in various plastics as a flame retardant. These include high impact polystyrenes (HIPS) that are widely used for electrical appliances, electronic instruments and building materials. HIPS is a graft co-polymer of polystyrene and dispersed polybutadiene (PB) rubber.

Chapter 4 discusses the thermal degradation to polybrominated toluenes rather than polybrominated dibenzofurans and dibenzo-p-dioxins at temperatures around 600 deg. C and the behavoir on incineration. The synergistic role of antimony trioxide is explained.

2. Absence of PBDFs and PBDDs in EBP and EBP formulated with antimony trioxide

 Ranken et al. (2015)demonstrated that the PBDD/PBDF content of a sample of Albemarle Corporation SAYTEX (EBP) was below the concentrations specified by the German Ordinance for all eight congeners.

 This is supported a 1994 internal memo[1]by Ethyl Corporation (now Albemarle Corporation), which reported that less than the limit of quantification of 0.5 ppb for separate PBDFs and PBDDs was present in the EBP/antimony trioxide flame retardant produced by Ethyl Corporation. This memo contains a table of results extracted from a larger report on various flame retardants. These results were obtained using the same procedure of extraction by Soxhlet extraction followed by GC-MS analysis (as reported in Ranken 1992 and Ranken 1993).

The Ranken et al., 2015 report demonstrates that the PBDD/PBDF content of a sample of Albemarle Corporation SAYTEXwas below the concentrations specified by the German Ordinance for all eight congeners:

Concentration (ppb) of eight PBDD/PBDFs in SAYTEX 8010 as proscribed by theGerman Chemical Prohibition Ordnance(ChemVerbotsV)(Ranken 2015).

 

	Congener	Concentration in SAYTEX 8010 (ppb)	Limit of Quantification (ppb)
Group 1
2,3,7,8-Tetrabromodibenzo-p-dioxins	2,3,7,8-TBDD	ND	0.005
2,3,7,8-Tetrabromodibenzofuran	2,3,7,8-TBDF	0.023	Not specified
1,2,3,7,8-Pentabromodibenzo-p-dioxins	1,2,3,7,8-PeBDD	ND	0.010
2,3,4,7,8-Pentabromodibenzofuran	2,3,4,7,8-PeBDF	0.048	Not specified
	Σ (Group 1)	<1
Group 2
1,2,3,7,8-Pentabromodibenzofuran	1,2,3,7,8-PeBDF	0.250	Not specified
1,2,3,4,7,8-Hexabromodibenzo-p-dioxins	1,2,3,4,7,8-HxBDD	ND	0.200
1,2,3,6,7,8-Hexabromodibenzo-p-dioxins	1,2,3,6,7,8-HxBDD	ND	0.200
1,2,3,7,8,9-Hexabromodibenzo-p-dioxins	1,2,3,7,8,9-HxBDD	ND	0.200
Total	Σ (Group 1 + 2)	< 5

ND = none detected. Below the Limit of Quantification (LOQ) defined as ten times the signal/noise ratio.

The Ethyl Corporation Interoffice Memo of 3 Feb. 1994 refers to analysis carried out on various flame retardants. Only Table IV was enclosed that refers to SAYTEX S-8010 (decabromodiphenylethane), which is EBP. The method used was the same as explained in Ranken (1992) and Ranken (1993) with extraction by Soxhlet. The analysis was carried out by the Trace Analysis Laboratories of Ethyl Corporation (now Albemarle Corporation) upon material produced by the Process Development Centre Market Development Unit of Ethyl Corporation in February 1992.

 

The table indicates that <1 ppb of the eight congeners is present in SAYTEX S-8010:

Concentration (ppb) of eight PBDD/PBDFs inSAYTEX 8010(decabromodiphenylethane)as proscribed by theGerman Chemical Prohibition Ordnance(ChemVerbotsV). From Table IV Page 2 from Ethyl Corporation (1994)

	Abbreviations	HIPS Test Burn Sample PMN-1	HIPS Test Burn Sample PMN-2
Group 1
2,3,7,8-Tetrabromodibenzo-p-dioxins	2378-TBDD	ND	0.05 ppb
1,2,3,7,8-Pentabromodibenzo-p-dioxins	12378 -PeBDD	ND	0.09 ppb
2,3,7,8-Tetrabromodibenzofuran	2378-TBDF	ND	0.04 ppb
2,3,4,7,8-Pentabromodibenzofuran	23478 -PeBDF	Not measured	Not measured
	Σ (Group 1)	<1
Group 2
1,2,3,4,7,8-Hexabromodibenzo-p-dioxins	123478 -HxBDD	ND	0.49 ppb
1,2,3,7,8,9-Hexabromodibenzo-p-dioxins	123789 -HxBDD	ND	0.49 ppb
1,2,3,6,7,8-Hexabromodibenzo-p-dioxins	123678 -HxBDD	ND	0.49 ppb
1,2,3,7,8-Pentabromodibenzofuran	12378 -PeBDF	ND	0.01 ppb
	Σ (Group 1 + 2)	<5

ND = none detected. Below the Limit of Quantification (LOQ) defined as ten times the signal/noise ratio.

 

3. Absence of polybrominated-benzofurans and -dibenzo-p-dioxins in flame retardant polymers

The question of whether polybrominated-benzofurans and -dibenzo-p-dioxins are present in EBP-containing products is not so readily addressed. Resins containing SAYTEX 8010 are produced and processed under a variety of conditions and may contain proprietary additives. Rankin et al. (2015) did not detect any of the eight congeners proscribed by the German Chemical Prohibition Ordnance(ChemVerbotsV) in HIPS formulations with EBP and Sb₂O₃flame retardant. The older GFA (1995) study on HIPS, PBT and PET samples containing EBP and Sb₂O₃shows that levels of eight polybrominated-benzofurans and polybrominated-dibenzo-p-dioxins were below the 1 ppb (Group 1) and 5 ppb (Group 1+2) limits. Both HIPS and PBT showed none detected.

A typical flame retarded-high impact polystyrene (HIPS) containing SAYTEX 8010 and antimony trioxide was investigated. The formulation was extruded, and injection moulded into plaques for analysis. The results show the formulation did not contain PBDDs/PBDFs above the concentrations specified by the Ordinance. (Ranken et al. 2015). See table below.

Concentration (ppb) of eight PBDD/PBDFs in HIPS/Sb₂O₃/SAYTEX 8010 formulation as proscribedby the German Chemical Prohibition Ordnance(ChemVerbotsV). Duplicate Analyses.

	Congener	Concentration (ppb)	Detection Limit (ppb)
Group 1	Group 1
2,3,7,8-Tetrabromodibenzo-p-dioxins	2,3,7,8-TBDD	ND	0.02; 0.03
1,2,3,7,8-Pentabromodibenzo-p-dioxins	1,2,3,7,8-PeBDD	ND	0.09; 0.09
2,3,7,8-Tetrabromodibenzofuran	2,3,7,8-TBDF	ND	0.02; 0.03
2,3,4,7,8-Pentabromodibenzofuran	2,3,4,7,8-PeBDF	ND	0.09; 0.08
	Σ (Group 1)	<1
Group 2	Group 2
1,2,3,4,7,8-Hexabromodibenzo-p-dioxins	1,2,3,4,7,8-HxBDD	ND	0.29; 0.27
1,2,3,7,8,9-Hexabromodibenzo-p-dioxins	1,2,3,6,7,8-HxBDD	ND	0.29; 0.27
1,2,3,6,7,8-Hexabromodibenzo-p-dioxins	1,2,3,7,8,9-HxBDD	ND	0.29; 0.27
1,2,3,7,8-Pentabromodibenzofuran	1,2,3,7,8-PeBDF	ND	0.09; 0.08
	Σ (Group 1 + 2)	<5

ND = none detected. Below the Limit of Quantification (LOQ) defined as ten times the signal/noise ratio.

  GFA, 1995 analysed for poly-brominated dibenzofurans (PBDFs) and polybrominated dibenzo-p-dioxins (PBDDs) in three different plastics that contained EBP (which the report refers to as the brominated flame retardant BrFR1). The four samples of three polymers that contained EBP were tested with corresponding blanks that contained only antimony trioxide as fillers. The method blanks for the three plastics did not contain EBP or antimony trioxide. The samples were:

·        Two samples of HIPS (High Impact Polystyrene),

·        PBT (Polybutylenephthalate),

·        PET (Polyethyleneterephthalate)

The method was as follows:

1.     Dissolve in toluene, add radiolabelled internal standards and reflux for 3 hours.

2.     Precipitate in nonane and filter (Extract I).

3.     Re-extraction of the filtered residues.

4.     Reflux in toluene. (Extract II).

5.     Combine Extracts I and II.

6.     Liquid chromatography clean-up using four absorbents (basic alumina, carbon/Celite, acidic alumina and Florisil).

7.     Addition of the radiolabelled recovery standard.

8.     Capillary GC-FID and GC-MS.

 The Table below gives the approximate limits of quantification obtained.

Limits of Quantification, rounded to 1 decimal place

 

	Abbreviation	Limit of Quantification (LOQ)
Polybrominated dibenzo-p-dioxins
2,3,7,8-Tetrabromodibenzo-p-dioxins 2,3,7,8-Tetrabromooxanthrene Brc1cc2Oc3cc(Br)c(cc3Oc2cc1Br)Br Mol Wt: 499.78	2378-TetraBDD	<0.03 μg/kg = <0.03 ppb
1,2,3,7,8/1,2,3,6,7,8-Pentabromodibenzo-p-dioxins	12378/123678-PentaBDD	<0.1 μg/kg = <0.1 ppb
1,2,3,4,7,8-Hexabromodibenzo-p-dioxins	123478-HexaBDD	<0.3 μg/kg = <0.3 ppb
1,2,3,7,8,9-Hexabromodibenzo-p-dioxins	123789-HexaBDD	<0.3 μg/kg = <0.3 ppb
1,2,3,4,6,7,8-Heptabromodibenzo-p-dioxins	1234678-HeptaBDD	<0.6 μg/kg = <0.6 ppb
Octabromodibenzo-p-dioxin	OctaBDD	<2.0 μg/kg = <2 ppb
Polybrominated dibenzofurans (PBDF)
2,3,7,8-Tetrabromodibenzofuran CAS# 67733-57-7 Brc1cc2c(cc1Br)oc1c2cc(Br)c(c1)Br Mol Wt: 483.78 g/mol	2378-TetraBDF	<0.1 μg/kg = <0.1 ppm
1,2,3,7,8-Pentabromodibenzofuran	12378-PentaBDF	<0.1 μg/kg = <0.1 ppb
2,3,4,7,8-Pentabromodibenzofuran	23478-PentaBDF	<0.1 μg/kg = <0.1 ppb
1,2,3,4,7,8/1,2,3,6,7,8-Hexabromodibenzofuran	123478/123678-HexaBDF	<0.4 μg/kg = <0.4 ppb
2,3,4,6,8,7-Hexabromodibenzofuran	234687-HexaBDF	<0.4 μg/kg = <0.4 ppb
1,2,3,7,8,9-Hexabromodibenzofuran	123789-HexaBDF	<1.0 μg/kg = <1 ppb
1234678-Heptabromodibenzofuran	1234678-HexaBDF	<0.5 μg/kg = <0.5 ppb
Octabromodibenzofuran	OctaBDF	<2.0 μg/kg = <2 ppb

Congeners from the German Prohibition Ordinance (CHemVerbotsV) are listed below with an indication of whether they were measured or not.

Group 1          2,3,7,8-tetrabromodibenzodioxin (TBDD)        YES

1,2,3,7,8-pentabromodibenzodioxin (PeBDD)  YES

2,3,7,8-tetrabromodibenzofuran (TBDF)          YES

2,3,4,7,8-pentabromodibenzofuran (PeBDF);    YES

 

Or more than 5 ppb of the sum of eight congeners.

Group 1          2,3,7,8-tetrabromodibenzodioxin (TBDD)        YES

1,2,3,7,8-pentabromodibenzodioxin (PeBDD)  YES

2,3,7,8-tetrabromodibenzofuran (TBDF)          YES

2,3,4,7,8-pentabromodibenzofuran (PeBDF);    YES

Group 2          1,2,3,4,7,8-hexabromodibenzodioxin (HxBDD)YES but cannot be resolved

1,2,3,7,8,9-hexabromodibenzodioxin (HxBDD)YES

1,2,3,6,7,8-hexabromodibenzodioxin (HxBDD) YES but cannot be resolved

1,2,3,7,8-pentabromodibenzofuran (PeBDF)     YES

  Concentration (ppb) of eight PBDD/PBDFsinSb2O3/SAYTEX 8010 formulation added to HIPS, PBT and PET plastics as proscribedby theGerman Chemical Prohibition Ordnance(ChemVerbotsV):

	Congener	HIPS Sample 1	HIPS Sample 2	PBT	PET
Group 1	Group 1
2,3,7,8-Tetrabromodibenzo-p-dioxins	2,3,7,8-TBDD	ND	ND	ND	ND
1,2,3,7,8-Pentabromodibenzo-p-dioxins	1,2,3,7,8-PeBDD	ND	ND	ND	ND
2,3,7,8-Tetrabromodibenzofuran	2,3,7,8-TBDF	ND	ND	ND	ND
2,3,4,7,8-Pentabromodibenzofuran	2,3,4,7,8-PeBDF	ND	ND	ND	0.6 ppb
Σ (Group 1) <1 ppb		<<1 ppb	<<1 ppb	<<1 ppb	0.6 ppb
Group 2	Group 2
1,2,3,4,7,8-Hexabromodibenzo-p-dioxins	1,2,3,4,7,8-HxBDD	ND	ND	ND	ND
1,2,3,7,8,9-Hexabromodibenzo-p-dioxins	1,2,3,6,7,8-HxBDD	ND	ND	ND	1.8 ppb
1,2,3,6,7,8-Hexabromodibenzo-p-dioxins	1,2,3,7,8,9-HxBDD	ND	ND	ND	ND
1,2,3,7,8-Pentabromodibenzofuran	1,2,3,7,8-PeBDF	ND	ND	ND	ND
Σ (Group 1 + 2) <5 ppb		<<5 ppb	<<5 ppb	<<5 ppb	2.4 ppb

ND = none detected. Below the Limit of Quantification (LOQ) defined as ten times the signal/noise ratio.

  Only PET showed one of the proscribed polybrominated benzofurans and dibenzo-p-dioxins above the Limit of Quantification.

4.Thermal decomposition of EBP at experimental conditions (pyrolysis at 600 deg. C)

Jakab et al., 2003explains the differences in decomposition of decabromodiphenyl ether (Br10-DPE) and decabromodiphenyl ethane (EBP; referred to in the paper as Br10-DB). HIPS is a graft co-polymer of polystyrene (PS) and polybutadiene (PB). The table below shows the composition of the HIPS samples used.

Applicant's summary and conclusion

Conclusions:

In a numbe rof studies it has been demonstrated that high temperature treatment of EBP and EBP and antimony trioxide including waste incineration containing polymers does not lead to polybrominated dioxine - or furane formation. The values were generally below the limtis of detection of the analytical methods. Under experimental laboratory conditions it was demonstrated that pyrolysis at around 600 deg. C can lead to a clevage of the ethylene bridge and formation of polybrominated toluene in particular pentabromo toluene. these conditiosn are not appearing in the life cycle of the product and at higher temperatures of waste incinearation further oxidation to CO2 and bromide species is known to occur.
Therfore an exposure assessment for these products was not performed in this update of the dossier.

Executive summary:

This report summarises various internal reports for the analytical determination of polybrominated dibenzofurans (PBDFs) and dibenzo-p-dioxins (PBDDs) under various conditions by Albemarle and external contractors. These include elevated temperature conditions simulating incineration of flame retarded plastic materials and recycling cycles. These determinations were performed in the main to investigate compliance of polymers containing EBP and EBP plus antimony trioxide in typical concentrations with the German Dioxane Ordinance and EPA guidelines on determining the absence of brominated dioxins and furans during combustion processes. The reference chemicals were also chosen on this basis. The data demonstrate that the flame retardant, the polymer containing the flame retardant and the polymer containing the flame retardant after simulated recycling do not contain PBDDs/PBDFs above the concentrations specified in the Ordinance and are generally below the limits of quantification of the respective methods. A mechanism for the degradation of EBP is also presentedthat supports the conclusion thatPBDDs/PBDFs are not formed.