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. The ...
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, ...
C
6H
4(CO
2C
4H
9)
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 commerc ...
.
[ 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
1-Butanol, also known as butan-1-ol or ''n''-butanol, is a primary alcohol with the chemical formula C4H9OH and a linear structure. Isomers of 1-butanol are isobutanol, butan-2-ol and ''tert''-butanol. The unmodified term butanol usually refers t ...
. 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 biodegrada ...
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 pat ...
'' 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 ato ...
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
The ''n''-octanol-water partition coefficient, ''K''ow is a partition coefficient for the two-phase system consisting of ''n''-octanol and water. ''K''ow is also frequently referred to by the symbol P, especially in the English literature. It is a ...
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 waste ...
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 phases ...
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 c ...
.
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 political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been des ...
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 European Union
The European Union (EU) is a supranational political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been des ...
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 be ...
(U.S. EPA).
DBP was added to the California Proposition 65 (1986)
Proposition 65 (formally titled The Safe Drinking Water and Toxic Enforcement Act of 1986, and also referred to as Prop 65) is a California law passed by direct voter initiative in 1986 by a 63%–37% vote. Its goals are to protect drinking water s ...
list of suspected teratogens in November 2006. It is a suspected 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 c ...
. 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.[
]
See also
* Phthalic acid
Phthalic acid is an aromatic dicarboxylic acid, with formula C6H4(CO2H)2. Although phthalic acid is of modest commercial importance, the closely related derivative phthalic anhydride is a commodity chemical produced on a large scale. Phthalic aci ...
* Phthalates
Phthalates (, ), or phthalate esters, are esters of phthalic acid. They are mainly used as plasticizers, i.e., substances added to plastics to increase their flexibility, transparency, durability, and longevity. They are used primarily to soften ...
* Diisobutyl phthalate
Diisobutyl phthalate (DIBP) is prepared by esterification process of isobutanol and phthalic anhydride. Its structural formula is C6H4(COOCH2CH(CH3)2)2.
DIBP is an odorless plasticizer and has excellent heat and light stability. It is the lowest ...
(DIBP)
* 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 ...
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