Dibutyl phthalate (DBP) is an

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. Th ...

which is commonly used as a

plasticizer A plasticizer ( UK: plasticiser) is a substance that is added to a material to make it softer and more flexible, to increase its plasticity, to decrease its viscosity, and/or to decrease friction during its handling in manufacture. Plasticiz ...

because of its low toxicity and wide liquid range. With the

chemical formula In chemistry, a chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, ...

C₆H₄(CO₂C₄H₉)₂, it is a colorless oil, although commercial samples are often yellow.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.

Production and use

DBP is produced by the reaction of ''n''-butanol with

phthalic anhydride Phthalic anhydride is the organic compound with the formula C6H4(CO)2O. It is the anhydride of phthalic acid. Phthalic anhydride is a principal commercial form of phthalic acid. It was the first anhydride of a dicarboxylic acid to be used commer ...

. DBP is an important plasticizer that enhances the utility of some major engineering plastics, such as PVC. Such modified PVC is widely used in plumbing for carrying sewerage and other corrosive materials.

Degradation

Hydrolysis of DBP leads to phthalic acid and 1-butanol.

Monobutyl phthalate Monobutyl phthalate (MBP) is an organic compound with the condensed structural formula CH3(CH2)3OOCC6H4COOH. It is a white solid that features both an butyl ester group and a carboxylic acid group. It is the major metabolite of dibutyl phthalate. ...

(MBP) is its major metabolite.

Biodegradation

Biodegradation Biodegradation is the breakdown of organic matter by microorganisms, such as bacteria and fungi. It is generally assumed to be a natural process, which differentiates it from composting. Composting is a human-driven process in which biodegra ...

by microorganisms represents one route for remediation of DBP. For example, ''

Enterobacter ''Enterobacter'' is a genus of common Gram-negative, facultatively anaerobic, rod-shaped, non-spore-forming bacteria of the family Enterobacteriaceae. It is the type genus of the order Enterobacterales. Several strains of these bacteria are ...

'' species can biodegrade municipal solid waste—where the DBP concentration can be observed at 1500 ppm—with a

half-life Half-life (symbol ) is the time required for a quantity (of substance) to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable ...

of 2–3 hours. In contrast, the same species can break down 100% of dimethyl phthalate after a span of six days. The white rot fungus ''

Polyporus brumalis ''Polyporus brumalis'' is an inedible species of fungus in the genus ''Polyporus ''Polyporus'' is a genus of poroid fungi in the family Polyporaceae. Taxonomy Italian botanist Pier Antonio Micheli introduced the genus in 1729 to include 14 ...

'' degrades DBP. DBP is leached from landfills.

Physical properties relevant to biodegradation

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

landfill A landfill site, also known as a tip, dump, rubbish dump, garbage dump, or dumping ground, is a site for the disposal of waste materials. Landfill is the oldest and most common form of waste disposal, although the systematic burial of the wast ...

s. DBP has a low

vapor pressure Vapor pressure (or vapour pressure in English-speaking countries other than the US; see spelling differences) or equilibrium vapor pressure is defined as the pressure exerted by a vapor in thermodynamic equilibrium with its condensed pha ...

of 2.67 x 10⁻³ Pa. Thus DBP does not evaporate readily (hence its utility as a plasticizer). The Henry's Law constant is 8.83 x 10⁻⁷ atm-m³/mol.

Legislation

DBP is also a putative

endocrine disruptor Endocrine disruptors, sometimes also referred to as hormonally active agents, endocrine disrupting chemicals, or endocrine disrupting compounds are chemicals that can interfere with endocrine (or hormonal) systems. These disruptions can cause ...

European Union

The use of this substance in cosmetics, including nail polishes, is banned in the

European Union The European Union (EU) is a supranational union, supranational political union, political and economic union of Member state of the European Union, member states that are located primarily in Europe, Europe. The union has a total area of ...

under Directive 76/768/EEC 1976. The use of DBP has been restricted in the European Union for use in children's toys since 1999. 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) Also includes the 2004 addendum. Based on urine samples from people of different ages, the European Commission

Scientific Committee on Health and Environmental Risks The Scientific Committee on Health and Environmental Risks (SCHER) is one of the independent scientific committees managed by the Directorate-General for Health and Consumer Protection of the European Commission, which provide scientific advice to ...

(SCHER) concluded that total exposures to DBP should be further reduced. Under

Directive 2011/65/EU revision 2015/863,Commission Delegated Directive (EU) 2015/863 of 31 March 2015 amending Annex II to Directive 2011/65/EU of the European Parliament and of the Council as regards the list of restricted substances
/ref> DBP is limited to max 1000 ppm concentration in any homogenous material.

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 The Environmental Protection Agency (EPA) is an independent executive agency of the United States federal government tasked with environmental protection matters. President Richard Nixon proposed the establishment of EPA on July 9, 1970; it ...

(U.S. EPA). DBP was added to the California Proposition 65 (1986) list of suspected teratogens in November 2006. It is a suspected

. It was used in many consumer products, e.g.,

nail polish Nail polish (also known as nail varnish or nail enamel) is a lacquer that can be applied to the human fingernail or toenails to decorate and protect the nail plates. The formula has been revised repeatedly to enhance its decorative properties ...

, 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).

Safety

Phthalates are noncorrosive with low acute toxicity.

References

External links

*
Dibutyl Phthalate and Cosmetics

Hazardous substance fact sheet

* ttps://www.cdc.gov/niosh/npg/npgd0187.html CDC - NIOSH Pocket Guide to Chemical Hazards {{DEFAULTSORT:Dibutyl Phthalate Plasticizers Phthalate esters Endocrine disruptors