Dibutyl phthalate

Description

Dibutyl phthalate is included as an insect repellent in some aerosol sprays used to treat flystrike in sheep. It is colorless oily liquid with a very weak aromatic odor.

Description

Di-n-butyl phthalate (DBP) is an oily, sparingly water-soluble liquid with a very high boiling point (350 oC). In 1962, R. H. Mills, M. W. Farrar, and O. J. Weinkauff at Monsanto reported its preparation from phthalic acid and?n-butyl chloride. More recently, the predominant manufacturing method was the reaction of phthalic anhydride with?n-butyl alcohol.
DBP’s original use was as an insect repellent that was impregnated into clothing; but it gained its greatest use (and notoriety) as a plasticizer for poly(vinyl chloride) used in many consumer products. In the 1980s, toxicological studies revealed it to be a suspected endocrine disruptor and teratogen; and by the late 2000s, it had been banned for all uses in the United States and the European Union.
Some chemical companies, including producers of phthalate esters, are now marketing?phthalate replacements. Examples are Eastman’s Benzoflex (benzoate ester) and Effusion (di-n-butyl terephthalate) lines of PVC plasticizers.

Chemical properties

Dibutyl phthalate occurs as an odorless, oily, colorless, or very slightly yellow-colored, viscous liquid.

Physical properties

Colorless to pale yellow, oily, viscous liquid with a mild, aromatic odor

The Uses of Dibutyl phthalate

Dibutyl phthalate is used in plasticizers, cosmetics, safety glass, insecticides, printing inks, paper coatings, adhesives, elastomers and explosives; solvent in polysulfide dental impression materials; solvent for perfume oils; perfume fixative; textile lubricating agent; solid rocket propellent; emollient in aerosol antiperspirants; insect repeller; plasticizer in various plastic materials.

The Uses of Dibutyl phthalate

Di-n-butyl phthalate has been used as an insect repellant.

The Uses of Dibutyl phthalate

A phthalate metabolite with genotoxic effect.

The Uses of Dibutyl phthalate

Plasticizer; solvent for oil-soluble dyes, insecticides and other organics; antifoam agent; textile fiber lubricant; manometer fluid; fragrance fixative; insect repellent.

Production Methods

Dibutyl phthalate is produced from n-butanol and phthalic anhydride in an ester formation reaction.

Definition

ChEBI: A phthalate ester that is the diester obtained by the formal condensation of the carboxy groups of phthalic acid with two molecules of butan-1-ol.

General Description

Dibutyl phthalate is a colorless oily liquid. Dibutyl phthalate is insoluble in water. The primary hazard is the threat to the environment. Immediate steps should be taken to limit its spread to the environment. Since Dibutyl phthalate is a liquid Dibutyl phthalate can easily penetrate the soil and contaminate groundwater and nearby streams. Dibutyl phthalate is combustible though Dibutyl phthalate may take some effort to ignite. Dibutyl phthalate is used in paints and plastics and as a reaction media for chemical reactions.

Air & Water Reactions

Insoluble in water.

Reactivity Profile

Dibutyl phthalate is an ester. Esters react with acids to liberate heat along with alcohols and acids. Strong oxidizing acids may cause a vigorous reaction that is sufficiently exothermic to ignite the reaction products. Heat is also generated by the interaction of esters with caustic solutions. Flammable hydrogen is generated by mixing esters with alkali metals and hydrides. Avoid contact with strong oxidizing agents and strong bases. Will not polymerize. [USCG, 1999]. Can generate electrostatic charges. [Handling Chemicals Safely 1980. p. 250].

Health Hazard

The toxicity of this compound is very low. Inhumans, oral intake of dibutyl phthalate at adose level of 150 mg/kg may cause nausea,vomiting, dizziness, hallucination, distortedvision, lacrimation, and conjunctivitis withprompt recovery. It metabolizes to monobutylester and phthalic acid and is excreted in urine.The inhalation toxicity should be insignificantbecause of its negligible low vapor pressure[<0.1 torr at 20°C (68°F)]. However, expo sure to its mist or aerosol can cause irritationof eyes and mucous membranes
LD50 value, oral (mice): 5300 mg/kg.

Fire Hazard

Combustible.

Flammability and Explosibility

Non flammable

Pharmaceutical Applications

Dibutyl phthalate is used in pharmaceutical formulations as a plasticizer in film-coatings. It has been evaluated as a pore-forming agent in novel delivery systems.It is also used extensively as a solvent, particularly in cosmetic formulations such as antiperspirants, hair shampoos, and hair sprays. In addition to a number of industrial applications, dibutyl phthalate is used as an insect repellent, although it is not as effective as dimethyl phthalate.

Contact allergens

It is mainly used as a nonreactive epoxy diluent.

Safety Profile

Moderately toxic by intraperitoneal and intravenous routes. Mildly toxic by ingestion. Human systemic eye effects by ingestion, hallucinations, dstorted perceptions, nausea or vomiting, and kidney, ureter, or bladder changes. Experimental teratogenic and reproductive effects. Mutation data reported. Combustible when exposed to heat or flame; can react with oxidizing materials. Violent reaction with Cl2. Incompatible with chlorine. To fight fire, use CO2, dry chemical. When heated to decomposition it emits acrid smoke and fumes. See also ESTERS, PHTHALIC ACID, and n BUTYL ALCOHOL.

Safety

Dibutyl phthalate is generally regarded as a relatively nontoxic material, although it has occasionally been reported to cause hypersensitivity reactions. It is widely used in topical cosmetic and some oral pharmaceutical formulations.
LD50 (mouse, IV): 0.72g/kg
LD50 (mouse, oral): 5.3g/kg
LD50 (rat, oral): 8.0g/kg
LD50 (rat, IP): 3.05mL/kg

Potential Exposure

AgriculturalChemical; Tumorigen, Mutagen; Reproductive Effector;Human Data. Used in making vinyl compounds, inplasticizing vinyl acetate emulsion systems, and in plasticizing cellulose esters. Also used as a lacquer solvent (nail polish remover) and insect repellent.

First aid

If this chemical gets into the eyes, remove any contact lenses at once and irrigate immediately for at least 15 min,occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts the skin, removecontaminated clothing and wash immediately with soap andwater. Seek medical attention immediately. If this chemicalhas been inhaled, remove from exposure, begin rescue breathing (using universal precautions, including resuscitation mask)if breathing has stopped and CPR if heart action has stopped.Transfer promptly to a medical facility. When this chemicalhas been swallowed, get medical attention. Give large quantities of water and induce vomiting. Do not make an unconscious person vomit.

Source

Detected in distilled water-soluble fractions of new and used motor oil at concentrations of 38 to 43 and 15 to 23 μg/L, respectively (Chen et al., 1994). Leaching from flexible plastics in contact with water. Laboratory contaminant.

Environmental Fate

Biological. Under aerobic conditions using a freshwater hydrosol, mono-n-butyl phthalate and phthalic acid were produced. Under anaerobic conditions, phthalic acid was not present (Verschueren, 1983). In anaerobic sludge, di-n-butyl phthalate degraded as follows: monobutyl phthalate to phthalic acid to protocatechuic acid followed by ring cleavage and mineralization (Shelton et al., 1984). Engelhardt et al. (1975) reported that a variety of microorganisms were capable of degrading of di-n-butyl phthalate and suggested the following degradation scheme: di-n-butyl phthalate to mono-n-butyl phthalate to phthalic acid to 3,4-dihydroxybenzoic acid and other unidentified products. Di-n-butyl phthalate was degraded to benzoic acid by tomato cell suspension cultures (Lycopericon lycopersicum) (Pogány et al., 1990).
In a static-culture-flask screening test, di-n-butyl phthalate showed significant biodegradation with rapid adaptation. The ester (5 and 10 mg/L) was statically incubated in the dark at 25°C with yeast extract and settled domestic wastewater inoculum. After 7 days, 100% biodegradation was achieved (Tabak et al., 1981).
Soil. Under aerobic conditions using a fresh-water hydrosol, mono-n-butyl phthalate and phthalic acid were produced. Under anaerobic conditions, however, phthalic acid was not formed (Verschueren, 1983).
Photolytic. An aqueous solution containing titanium dioxide and subjected to UV radiation (l >290 nm) produced hydroxyphthalates and dihydroxyphthalates as intermediates (Hustert and Moza, 1988).
Chemical/Physical. Pyrolysis of di-n-butyl phthalate in the presence of polyvinyl chloride at 600°C gave the following compounds: indene, methylindene, naphthalene, 1- methylnaphthalene, 2-methylnaphthalene, biphenyl, dimethylnaphthalene, acenaphthene, fluorene, methylacenaphthene, methylfluorene and six unidentified compounds (Bove and Dalven, 1984).
Under alkaline conditions, di-n-butyl phthalate will initially hydrolyze to n-butyl hydrogen phthalate and n-butanol. The monoester will undergo further hydrolysis forming o-phthalic acid and n-butanol (Kollig, 1993).

storage

Dibutyl phthalate should be stored in a well-closed container in a cool, dry, location. Containers may be hazardous when empty since they can contain product residues such as vapors and liquids.

Shipping

Based on regulations, it may be classified asan Environmentally hazardous substances, liquid, n.o.s. Itfalls in Hazard Class 9 and Packing Group III.[20,21]

Purification Methods

Wash DBP with H2O (to free it from alcohol), then dilute NaOH (to remove any butyl hydrogen phthalate or acid), aqueous NaHCO3 (charcoal), then distilled water. Dry it (CaCl2), distil it at 10torr or less, and store it in a desiccator over P2O5. [Beilstein 9 II 586, 9 III 4102, 9 IV 3175.]

Toxicity evaluation

Acute oral LD₅₀ for rats: >6,000 mg/kg

Incompatibilities

Dibutyl phthalate reacts violently with chlorine. It also reacts with oxidizing agents, acids, bases, and nitrates.

Regulatory Status

Included in the FDA Inactive Ingredients Database (oral capsules, delayed action, enteric coated, and controlled release tablets). Included in nonparenteral medicines licensed in the UK (oral capsules, tablets, granules; topical creams and solutions).