Dibutyl phthalate (DBP) is an organic compound commonly used plasticizer. With the chemical formula C6H4(CO2C4H9)2, it is a colorless oil, although commercial samples are often yellow. Because of its low toxicity and wide liquid range, it is used as a plasticizer.[3]

Production and use

DBP is produced by the reaction of n-butanol with phthalic anhydride. These precursor compounds are produced cleanly and cheaply.[3]

DBP is an important plasticizer that allows major engineering plastics, such as PVC, to be used. Such modified PVC is widely used in plumbing for carrying sewerage and other corrosive materials.[3]



Like other phthalate esters, DBP undergoeshydrolysis to afford phthalic acid and 1-butanol.

C6H4(CO2C4H9)2 + 2 H2O → C6H4(CO2H)2 + 2 C4H9OH

This reaction is catalyzed by both acids and bases.[4]

In landfills

DBP has a low vapor pressure of 2.67 x 10−3 Pa. Thus DBP does not evaporate readily (hence its utility as a plasticizer).[5] I Henry’s Law constant is 8.83 x 10−7 atm-m3/mol.[4]

As reflected by its octanol-water partition coefficient of around 4, it is lipophilic, which means that it is not readily mobilized (dissolved by) water. Nonetheless dissolved organic compounds (DOC) increase its mobility in landfills.[6][7]


Biodegradation by microorganisms represents one route for remediation of pollution by DBP. For example, Enterobacter species can biodegrade municipal solid waste—where the DBP concentration can be observed at 1500 ppm—with a half-life of 2–3 hours. In contrast, the same species can break down 100% of dimethyl phthalate after a span of six days.[8] The white rot fungus Polyporus brumalis degrades DBP.[9]


DBP is also a putative endocrine disruptor.[10]

European Union

The use of this substance in cosmetics, including nail polishes, is banned in the European Union under Directive 76/768/EEC 1976.[11]

The use of DBP has been restricted in the European Union for use in children's toys since 1999.[12]

An EU Risk Assessment has been conducted on DBP and the final outcome has now been published in the EU Official Journal. To eliminate a potential risk to plants in the vicinity of processing sites and workers through inhalation, measures are to be taken within the framework of the IPPC Directive (96/61/EC) and the Occupational Exposure Directive (98/24/EC)[13] Also includes the 2004 addendum.

Based on urine samples from people of different ages, the European Commission Scientific Committee on Health and Environmental Risks (SCHER) concluded that total exposures to DBP for should be further reduce exposures are needed.[14]

United States

Dibutyl phthalate (DBP) is one of the six phthalic acid esters found on the Priority Pollutant List, which consists of pollutants regulated by the United States Environmental Protection Agency (U.S. EPA).[15] DBP is leached from landfills.[16] However, due to the fact that DBP holds a density less than that of water, a thin surface film forms at the air-water interface.

DBP was added to the California Proposition 65 (1986) list of suspected teratogens in November 2006. It is a suspected endocrine disruptor.[10] It was used in many consumer products, e.g., nail polish, but such usages has declined since around 2006. It was banned in children's toys, in concentrations of 1000 ppm or greater, under section 108 of the Consumer Product Safety Improvement Act of 2008 (CPSIA).

See also


  1. ^ a b c d "NIOSH Pocket Guide to Chemical Hazards #0187". National Institute for Occupational Safety and Health (NIOSH). 
  2. ^ a b "Dibutyl Phthalate". Immediately Dangerous to Life and Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH). 
  3. ^ a b c Peter M. Lorz, Friedrich K. Towae, Walter Enke, Rudolf Jäckh, Naresh Bhargava, Wolfgang Hillesheim "Phthalic Acid and Derivatives" in Ullmann's Encyclopedia of Industrial Chemistry, 2007, Wiley-VCH, Weinheim. doi:10.1002/14356007.a20_181.pub2
  4. ^ a b Huang, Jingyu; Nkrumah, Philip N.; Li, Yi; Appiah-Sefah, Gloria (2013). Reviews of Environmental Contamination and Toxicology Volume 224. Reviews of Environmental Contamination and Toxicology. Springer, New York, NY. pp. 39–52. doi:10.1007/978-1-4614-5882-1_2. ISBN 9781461458814. 
  5. ^ Donovan, Stephen F. "New method for estimating vapor pressure by the use of gas chromatography". Journal of Chromatography A. 749 (1-2): 123–129. doi:10.1016/0021-9673(96)00418-9. 
  6. ^ Christensen, Thomas H; Kjeldsen, Peter; Bjerg, Poul L; Jensen, Dorthe L; Christensen, Jette B; Baun, Anders; Albrechtsen, Hans-Jørgen; Heron, Gorm. "Biogeochemistry of landfill leachate plumes". Applied Geochemistry. 16 (7-8): 659–718. doi:10.1016/s0883-2927(00)00082-2. 
  7. ^ Bauer, M.J.; Herrmann, R. (2016-07-02). "Dissolved organic carbon as the main carrier of phthalic acid esters in municipal landfill leachates". Waste Management & Research. 16 (5): 446–454. doi:10.1177/0734242x9801600507. 
  8. ^ Abdel daiem, Mahmoud M.; Rivera-Utrilla, José; Ocampo-Pérez, Raúl; Méndez-Díaz, José D.; Sánchez-Polo, Manuel. "Environmental impact of phthalic acid esters and their removal from water and sediments by different technologies – A review". Journal of Environmental Management. 109: 164–178. doi:10.1016/j.jenvman.2012.05.014. 
  9. ^ Ishtiaq Ali, Muhammad (2011). Microbial degradation of polyvinyl chloride plastics (PDF) (Ph.D.). Quaid-i-Azam University. p. 48. 
  10. ^ a b "National Report on Human Exposure to Environmental Chemicals". Centers for Disease Control and Prevention, U.S. Department of Health and Human Services. Retrieved 2009-03-14. 
  11. ^ EU Council Directive 76/768/EEC of 27 July 1976 on the approximation of the laws of the Member States relating to cosmetic products
  12. ^ Ban of phthalates in childcare articles and toys, press release IP/99/829, 10 November 1999
  13. ^ http://www.plasticisers.org/uploads/Risk%20assessments/DBP%20Risk%20Assessment%20Summary.pdf
  14. ^ "Phthalates in school supplies". GreenFacts Website. Retrieved 2009-06-10. 
  15. ^ Gao, Da-Wen; Wen, Zhi-Dan. "Phthalate esters in the environment: A critical review of their occurrence, biodegradation, and removal during wastewater treatment processes". Science of The Total Environment. 541: 986–1001. doi:10.1016/j.scitotenv.2015.09.148. 
  16. ^ Kjeldsen, Peter; Barlaz, Morton A.; Rooker, Alix P.; Baun, Anders; Ledin, Anna; Christensen, Thomas H. (2002-10-01). "Present and Long-Term Composition of MSW Landfill Leachate: A Review". Critical Reviews in Environmental Science and Technology. 32 (4): 297–336. doi:10.1080/10643380290813462. ISSN 1064-3389. 

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