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Decabromodiphenyl ether
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljökemi.
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi, Avdelningen för strukturkemi.
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi, Avdelningen för strukturkemi.
1999 (engelsk)Inngår i: Acta crystallographica Section C, ISSN 0108-2701, Vol. 55, nr 12, s. 2169-2171Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Bis(pentabromophenyl) ether, C12Br100, shows strangedifferences in the endocyclic angles between the twodifferent rings, although they are both substituted inthe same manner. Several short van der Waals contact distances give clues to the anomalous endocyclic anglesand some hints to the formation of decompositionproducts. We suggest that the intermolecular Br...Brcontacts contribute to the distortions of the ring systems.Usually distortions of this kind would be explained fromhighly anisotropic TLS behaviour, but the data from thetitle compound do not show any conclusive TLS effects.

sted, utgiver, år, opplag, sider
Wiley , 1999. Vol. 55, nr 12, s. 2169-2171
HSV kategori
Forskningsprogram
strukturkemi
Identifikatorer
URN: urn:nbn:se:su:diva-23147DOI: 10.1107/S0108270199008884OAI: oai:DiVA.org:su-23147DiVA, id: diva2:190398
Merknad
Part of urn:nbn:se:su:diva-167Tilgjengelig fra: 2004-05-13 Laget: 2004-05-13 Sist oppdatert: 2018-01-13bibliografisk kontrollert
Inngår i avhandling
1. Polybrominated diphenyl ethers and Tetrabromobisphenol A: Chemical synthesis, X-ray crystallography and Photochemical degradation
Åpne denne publikasjonen i ny fane eller vindu >>Polybrominated diphenyl ethers and Tetrabromobisphenol A: Chemical synthesis, X-ray crystallography and Photochemical degradation
2004 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

In the 1960s’ several manmade chemicals were detected in the environment, far from their sources. The most well known, and most likely those with the largest impact on the society, were DDT and its related compounds, and PCBs. These anthropogenic compounds were characterised as persistent organic pollutants (POPs). Following these POPs, several other chemicals have found their way to the environment. Over the last two decades, brominated flame retardants (BFRs) have become a matter of concern. Among all BFRs being commercially produced, tetrabromobisphenol A (TBBPA) and polybrominated diphenyl ethers (PBDEs) are the ones with the largest annual production. TBBPA is a very well defined compound while PBDEs consist of a large number of isomers and homologues (congeners). TBBPA does not seem to accumulate in biota as the PBDEs do, but is still of concern since it is found in e.g. sediments. The PBDEs can reach accumulation levels up in the ppm range. Still there is a lack of basic data for both TBBPA and PBDEs. Hence the present thesis is aimed to fill some of the data gaps by pursuing work on 1) photochemical degradation of TBBPA, some related compounds, and PBDEs; 2) synthesis of PBDE congeners and of TBBPA degradation products and 3) structural identifications of a selected set of BFRs by X-ray crystallography.

An apparatus was designed for carrying out photochemical degradation test of chemicals in general but in particular for BFRs. Quantum yield, rate of degradation and to some extent, identification of degradation products were performed on TBBPA, the corresponding chlorinated compound and a number of TBBPA degradation products and on 15 single PBDE congeners. In order to make this work possible all three nonaBDE isomers were synthesised via a reductive pathway applying sodium borohydride as a reducing agent. The three nona-BDEs were all characterised by X-ray crystallography.

The results of the photochemical degradation of TBBPA in water show a rapidly degradable compound also at pH’s that are environmentally relevant. Hence it is likely that TBBPA is not transported long distances, when exposed to sunlight, without undergoing photochemical degradation. It is notable that the TBBPA is degraded through cleavage between the two phenol rings. When the method was applied to study quantum yields and rate constants for the reaction of PBDE congeners it is evident that the decabromodiphenyl ether (BDE-209) is rapidly transformed. The reaction rate differ drastically from PBDEs with four or five bromine substituents that have very long half-lives when subjected to UV-light under the same conditions as for BDE-209. Lower brominated diphenyl ethers and polybrominated dibenzofurans were identified as PBDE degradation products. The synthesis of PBDEs and of TBBPA degradation products expanded the study as did the X-ray structure identifications.

sted, utgiver, år, opplag, sider
Stockholm: Institutionen för miljökemi, 2004. s. 96
HSV kategori
Identifikatorer
urn:nbn:se:su:diva-167 (URN)91-7265-878-9 (ISBN)
Disputas
2004-06-04, Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 12 A, Stockholm, 10:00
Opponent
Veileder
Tilgjengelig fra: 2004-05-13 Laget: 2004-05-13bibliografisk kontrollert

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