Embed Size (px)
Citation preview
13th Annual Green Chemistry and Engineering Conference, ACS 2009
Towards the Development of Green Plasticizers
Azadeh Kermanshahi pour*, David G. Cooper*, Milan Maric*, Jim A. Nicell**
*Department of Chemical Engineering** Department of Civil Engineering & Applied Mechanics
13th Annual Green Chemistry and Engineering Conference, ACS 2009
n Plasticizers are the most widely used synthetic additives in polymer industries.
n Sources of environmental contamination♦ Plasticizer manufacturing♦ Polymer processing♦ Waste disposal
n Sources of Human exposure♦ Consumption of contaminated seafood, plastic wrapped food♦ Blood transfusion
1/22
Plasticizers and Environmental Contamination
13th Annual Green Chemistry and Engineering Conference, ACS 2009
Plasticizer Molecular structure Toxicological research
Di-2-ethylhexyl adipate (DEHA)liver tumor in mice and rats4
2-ethylhexanoic(metabolite): the most potent peroxisome proliferator5
Di(2-ethylhexyl) terephthalate
2-ethylhexanoic(metabolite): the most potent peroxisome proliferator 5
COOR
COOR
RO C
O
(CH2)4 C
O
ORAdipates
Phthalates
Terephthalates COORROOC
Di(2-ethylhexyl) phthalate (DEHP)Carcinogen in mice1
Possible human carcinogen 2
Mono(2-ethylhexyl) phthalate (metabolite): endocrine distruptor 3
2/22
Plasticizers and their Potential Health Hazards
13th Annual Green Chemistry and Engineering Conference, ACS 2009
Plasticizer Structures
Plasticizer Molecular structure Toxicological research
Acetyl tributyl citrateCytotoxicity (growth inhibition) of mammalian cell 6
D(EG)DB, D(PG)DB
Resulted in accumulation of toxic metaboite as a result of interaction of Rhodotorula Rubra 7
HO C COOR
CH2
CH2 COOR
COOR
Citrates
OOO
O O
OOO
O O
Dibenzoates
3/22
13th Annual Green Chemistry and Engineering Conference, ACS 2009
Gartshore et al., 2002 7
Proposed biodegradation pathway of D(EG)DB by
Rhodotorula Rubra 7
Broth toxicity
Monobenzoate concentration
OO
O
O O
OHO
O
O
OHO
HO + OH
O
+ OH
O
4/22
Biodegradation of Di-ethylene Glycol Dibenzoate
13th Annual Green Chemistry and Engineering Conference, ACS 2009
n Evidence of the environmental and health impacts of the plasticizers supports the need to develop green plasticizers as alternatives to current commercially available plasticizers.
n Developing green plasticizers requires the identification of the functional groups in the chemical structure of these compounds that dictate the biodegradation mechanisms.
n The overall goal of this project is to identify the important functional groups that influence both the biotransformation mechanisms and plasticizing ability in order to design green plasticizers.
Objectives
5/22
13th Annual Green Chemistry and Engineering Conference, ACS 2009
The objectives of this study are:
n To evaluate the effect of the internal ether bond on the biodegradation mechanism of dibenzoate plasticizers.
n To study the biodegradation kinetics of plasticizers in orderto determine the extent of contribution of functional groupsin biodegradation rate of plasticizers and the metabolite.
♦ Ether function O
Objectives
6/22
13th Annual Green Chemistry and Engineering Conference, ACS 2009
OO
O
O O
OO
O
O
Di- ethylene glycol dibenzoate
1,6 hexanediol dibenzoate
n Does the ether function contribute to the persistence of dibenzoate metabolites?
OHO
O
O
OHO
O
Di- ethylene glycol monobenzoate
1,6 hexanediol monobenzoate
Effect of Ether Function
7/22
13th Annual Green Chemistry and Engineering Conference, ACS 2009
n Shake flask experiments♦ Rhodococcus rhodochrous, a common soil microorganism was
used for biodegradation study♦ Hexadecane was used as a primary carbon source for
substantial growth of microorganisms
n Analytical techniques♦ GC/FID for biodegradation monitoring/quantification♦ GC/MS for metabolite identification
Biodegradation Experiment
8/22
13th Annual Green Chemistry and Engineering Conference, ACS 2009
Time (hours)0 20 40 60 80 100 120
Con
cent
ratio
n (m
mol
/L)
0
1
2
3
4
5 D(EG)DBD(EG)MBBenzoic acid
OO
O
O O
OO
O
O
Time (hours)0 50 100 150 200 250 300 350
Con
cent
ratio
n (m
mol
/L)
0
1
2
3
4
51,6 hexanediol dibenzoateBenzoic aicd
Biodegradation of D(EG)DB and 1,6 Hexanediol Dibenzoate
9/22
13th Annual Green Chemistry and Engineering Conference, ACS 2009
Time (hours)0 20 40 60 80 100 120
Con
cent
ratio
n (m
mol
/L)
0
1
2
3
4
5 D(EG)DBD(EG)MBBenzoic acid
OO
O
O O
OO
O
O
Time (hours)0 50 100 150 200 250 300 350
Con
cent
ratio
n (m
mol
/L)
0
1
2
3
4
51,6 hexanediol dibenzoateUnknown metabolite Benzoic aicd
Biodegradation of D(EG)DB and 1,6 Hexanediol Dibenzoate
10/22
13th Annual Green Chemistry and Engineering Conference, ACS 2009
OO
OO
OO
OTMS OO
OTMSO
OO
OTMS
Pentadecane HexadecaneO
O
OTMSO
GC of Trimethylsilyl Derivatives of Biodegradation Broth
Unknown
11/22
13th Annual Green Chemistry and Engineering Conference, ACS 2009
O
D D
D
DD
ClOH
HO
+
OO
O
O
D
D
D
D
DD
D
D
D
D
1,6 hexanediol 1,6 hexanediol [2H5] dibenzoate[2H5] Benzoyl chloride
Synthesis of Deuterium Labeled Hexanediol Dibenzoate
12/22
13th Annual Green Chemistry and Engineering Conference, ACS 2009
6- [2H5] benzoyloxyhexanoic acid
4- [2H5] benzoyloxybutanoic acid
O
O
OHD
D
D
D
D
O
O
OHD
D
D
D
DO
O
O
OHD
D
D
D
DO
OH
OD
D
D
D
D
O
OD
D
D
D
D
[2H5] benzoic acid
6- [2H5] (benzoyloxy)hexan-1-ol
1-hexadecyl [2H5] benzoate
Metabolites of Biodegradation of Deuterium-Labeled Hexanediol Dibenzoate
13/22
13th Annual Green Chemistry and Engineering Conference, ACS 2009
n 1-hexadecyl benzoate was synthesized:
n The MS fragmentation of the authentic compound was identical to the one for metabolite.
Cl
O
+ HO O
O
Biodegradation Pathway Proposed for 1-hexadecyl benzoate
Final Confirmation of 1-Hexadecyl Benzoate as a Metabolite
O
O
OH
O
+ HO
From Plasticizer From Hexadecane
14/22
13th Annual Green Chemistry and Engineering Conference, ACS 2009
O
OO
O
O
OOH
O
OOH
O
O
OOH
O
OH
O
O
O
1,6 hexanediol dibenzoate
1-hexadecyl benzoate
Hydrolysis
Oxidation
β-Oxidation
β-Oxidation
15/22
Verification the Biodegradation Pathway of Hexanediol Dibenzoate
13th Annual Green Chemistry and Engineering Conference, ACS 2009
O
OOH
O
O
OOH
O
OH
O
O
OO
O
O
OOH
O
O
1,6 hexanediol dibenzoate
1-hexadecyl benzoate
16/22
Verification the Biodegradation Pathway of Hexanediol Dibenzoate
13th Annual Green Chemistry and Engineering Conference, ACS 2009
Proposed Biodegradation Pathway of 1,6 Hexanediol Dibenzoate
O
OO
O1,6 hexanediol dibenzoate
O
O
Hydrolysis
O
OOH
O
O
OOH
O
OH
O
6-(benzoyloxy)hexanoic acid
4-(benzoyloxy)butanoic acid
Benzoic acid
1,6 hexanediol monobenzoate
+ OH
O
Benzoic acid
Oxidation
β-Oxidation
β-Oxidation
HO
D
D
DD
DDD
D
D
D
D
DD
D
D
D
D
D
D
D D
DD
D
DD
DD
D
D
D
DD
DDD
D
D
D
D
DD
D
D
D
D
D
D
D
DD
D
DD
DD
D
1-[2H29]tetradecyl benzoate
[2H29]tetradecanol
D
O
OOH
D
D
D
DD
DDD
D
D
D
D
DD
D
D
D
D
D
D
D D
DD
D
DD
DD
D
[2H30]tetradecane
Oxidation
17/22
13th Annual Green Chemistry and Engineering Conference, ACS 2009
Proposed Biodegradation Pathway of Hexanediol Monobenzoate and Di-ethylene Glycol Monobenzoate
Hydrolysis
Slow
O
OO
OH
Di-ethylene glycol monobenzoate
HOO
OH
Di-ethylene glycol
O
OO OH
O
[2-(benzoyloxy)ethoxy] acetic acid
OH
O
Benzoic acid
+
OxidationO
OOH
O
O
OOH
O
OH
O
4-(benzoyloxy)butanoic acid
Benzoic acid
1,6 hexanediol monobenzoate
Oxidation
β-Oxidation
O
OOH
HOOH
OH
O
Benzoic acid 1,6 hexanediol
+
Hydrolysis
O
OOH
OOH4-(benzoyloxy)2-hydroxybutanoic acid
β-Oxidation
Slow
6-(benzoyloxy)hexanoic acid
18/22
13th Annual Green Chemistry and Engineering Conference, ACS 2009
On-going Research: Kinetic Studies in Bioreactors
n Bioreactor experiments ♦ Rhodococcus rhodochrous is grown on hexadecane♦ Plasticizer is introduced when the organisms are at stationary
phase
n Parameters monitored♦ Plasticizer and metabolite concentration♦ Biomass concentration
19/22
13th Annual Green Chemistry and Engineering Conference, ACS 2009
O
HO+
1,3 propanediol monobenzoate
O
O
OH
HO OH
O
O
OH
O
3-(benzoyloxy)propanoic acid
O
HO
20/22
O
HOO
OO
HOO
OO
Diethylene glycol monobenzoate 2-[2-(Benzoyloxy)ethoxy]acetic acid
D(EG)DB 1,3 propanediol dibenzoate
On-going Research: Kinetic Studies in Bioreactors
13th Annual Green Chemistry and Engineering Conference, ACS 2009
Commercial diethylene glycol
dibenzoate
Green 1,3 propanediol
dibenzoate
Dibenzoate degradation rate
1.5 mmol/min 1.3 mmol/min 1
Monobenzoate degradation rate
Slow Fast8
Oxidized monobenzoate degradation rate
Stable metabolite Slow
Biomass yield 0.24 (g/g) 0.55 (g/g) 2.3
CommercialGreen
≅
21/22
≅
On-going Research: Kinetic Studies in Bioreactors
13th Annual Green Chemistry and Engineering Conference, ACS 2009
n Presence of the ether function in commercial plasticizers has a significant influence on biodegradation mechanism.
n Biodegradation rate of monobenozate metabolite can be significantly enhanced by removing the ether function.
n These results show that hexanediol dibenzoate and propanediol dibenzoate can be considered as potential green plasticizers.
Conclusions
22/22
13th Annual Green Chemistry and Engineering Conference, ACS 2009
• Dr. Mamer, Mr. Choiniere and Dr. Lesimple (Mass Spectrometry Facility)
• Mr. Ranjan Roy (Deparment of Chemical Engineering )
• Dr. Violeta Taoder
• My colleagues
• Funding Sources: Natural Sciences and Engineering Research Council of Canada (NSERC), EJLB foundation
• Scholarships: NSERC, McGill Engineering Doctoral Award (MEDA) program, and the Eugenie Ulmer Lamothe (EUL) fund
Acknowledgments
13th Annual Green Chemistry and Engineering Conference, ACS 2009
1. K.E. Tomaszewski. In vitro steady-state levels of hydrogen peroxide after exposure of male F344 rats and female B6C3FX mice to hepatic peroxisome proliferators. Carcinogenesis. 1986, 7,1871.
2. US EPA. Integerated risk assessment. Di(2-ethylhexyl)phthalate (DEHP). CASRN 117-81-7 (03/01/1997).
3. T.M. Onorato, P.W. Brown, P. Morris. Mono-(2-ethylhexyl)phthalate increase permatocyte mitochondrial peroxiredoxin 3 and cyclooxygenase 2. Journal of Andrology. 2008, 29, 293.
4. Y. Keith, M.C. Cornu, P.M. Canning, J. Foster, J.C. Lhuguenot, C.R. Elcombe. Arch Toxicol. 1992, 66, 321.
5. M.C. Cornu, J.C. Lhuguenot, A.M. Brady, R. Moore, M.C. Elcombe. Identification of the proximate peroxisome proliferator(s) derived from di(2-ethylhexyl) adipates and species differences in response. Biochemical Pharmacology. 1992, 43, 2129.
6. K. Mochida, M. Gomyoda, T. Fujita. Bulletin of Environmental Contamination and Toxicology. 1996, 56, 635.
7. J. Gartshore, D.G. Cooper, J.A. Nicell. Biodegradation of plasticizers by Rhodotorula Rubra. Environmental Toxicology and Chemistry. 2002, 22, 1244.
References
