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Polybrominated benzoate esters are synthetic aromatic compounds derived from benzoic acid and modified by bromination and esterification.
Polybrominated benzoate esters provide excellent thermal stability, lipophilicity, and strong flame-retardant performance.
Polybrominated benzoate esters are widely used in plastics, foams, textiles, and electronic equipment to enhance fire safety.
CAS Number: 183658-27-7
Molecular Formula: C15H16Br4O2
Molar Mass: 549.91 g/mol
Synonyms: 2-Ethylhexyl 2,3,4,5-tetrabromobenzoate, 2,3,4,5-TetrabroMobenzoic Acid 2-Ethylhexyl Ester, Benzoic acid, 2,3,4,5-tetrabromo-, 2-ethylhexyl ester, 2-Ethylhexyl 2,3,4,5-tetrabromobenzoate @100 μg/mL in Toluene, 2-Ethylhexyl-2,3,4,5-Tetrabromobenzoate Solution, 2-Ethylhexyl 2,3,4,5-Tetrabromobenzoate(TBB), 2-Ethylhexyl-2,3,4,5-tetrabromobenzoate in toluene, 2-Ethylhexyl-2,3,4,5-tetrabromobenzoate 100 μg/ml Methanol
Polybrominated benzoate ester is a class of brominated aromatic compounds belonging to the family of brominated flame retardants (BFRs)
Structurally, they consist of a benzoic acid core esterified with various alcohols, with multiple hydrogen atoms on the benzene ring substituted by bromine atoms.
These substitutions greatly increase their thermal stability, persistence, and lipophilicity, which is why they are widely used as additives in plastics, textiles, foams, and electronic equipment to reduce flammability and improve fire safety.
Polybrominated benzoate esters typically appear as viscous oils or solid powders, depending on the degree of bromination and the ester substituent, and they are generally insoluble in water but soluble in organic solvents such as alcohols, ketones, and hydrocarbons.
Like other brominated flame retardants, they work by interfering with the combustion process, releasing bromine radicals that quench flame-propagating free radicals and suppress ignition.
However, due to their environmental persistence, bioaccumulation potential, and toxicological concerns, including possible endocrine disruption and developmental effects, Polybrominated benzoate esters have become subject to increasing regulatory scrutiny, and their use is being phased down or replaced by safer halogen-free alternatives in many regions.
Polybrominated benzoate ester is a new brominated flame retardant in air.
Polybrominated benzoate ester is a new brominated flame retardant.
Polybrominated benzoate ester may cause problems with development in animals and humans.
Polybrominated benzoate esters are synthetic brominated aromatic compounds that belong to the broader category of brominated flame retardants (BFRs).
Structurally, they are derivatives of benzoic acid esters, in which the benzene ring is substituted with multiple bromine atoms, and the carboxylic acid group is esterified with different alcohol moieties.
This dual structure — an aromatic core providing rigidity, ester linkages offering chemical reactivity, and extensive bromination conferring high thermal stability — makes Polybrominated benzoate esters highly effective as flame-retardant additives.
They are typically manufactured as viscous liquids, oily resins, or crystalline solids, with properties depending on the level of bromination and the alcohol group used in esterification.
Polybrominated benzoate esters are poorly soluble in water but are readily soluble in organic solvents such as acetone, alcohols, and aromatic hydrocarbons, which makes them compatible with a wide range of polymer matrices.
In terms of functionality, Polybrominated benzoate esters act as flame retardants by releasing bromine radicals during combustion, which interrupt the free radical chain reactions that sustain flames, thereby reducing ignition, suppressing flame spread, and promoting char formation.
Because of these properties, they have historically been incorporated into plastics, polyurethane foams, textiles, electronic housings, insulation materials, adhesives, and coatings, where fire safety is a priority.
In particular, they were widely used in consumer electronics and building materials during the late 20th century, as they significantly improved compliance with stringent fire safety regulations.
However, like many brominated flame retardants, Polybrominated benzoate esters exhibit persistence, bioaccumulation, and toxicity (PBT) characteristics.
Studies have shown that they can accumulate in the environment and living organisms, with residues detected in air, sediments, wildlife, and even human tissues.
Potential health concerns include endocrine disruption, neurotoxicity, reproductive effects, and developmental toxicity, similar to other persistent organic pollutants (POPs).
Because of these risks, their production and use have come under increasing regulatory restrictions.
Several Polybrominated benzoate ester formulations are now either banned, restricted, or being phased out under global chemical safety frameworks such as the Stockholm Convention and national environmental protection agencies.
Despite these concerns, research interest continues in monitoring Polybrominated benzoate esters as environmental contaminants, evaluating their toxicological pathways, and developing safer halogen-free alternatives such as phosphorus-based or nitrogen-based flame retardants.
Overall, Polybrominated benzoate esters represent a significant example of how a chemical group once considered highly valuable for fire prevention has also become a matter of environmental and public health concern, highlighting the need for balanced innovation in chemical safety.
Market Overview of Polybrominated Benzoate Ester:
The market for Polybrominated benzoate esters has historically been tied to their role as brominated flame retardants in plastics, foams, textiles, and electronic housings, where they offered cost-effective fire protection and compatibility with a wide range of polymer systems.
During the 1980s and 1990s, demand for Polybrominated benzoate esters grew alongside the global expansion of consumer electronics, building materials, and furniture industries, particularly in North America, Europe, and Asia-Pacific.
However, concerns over their persistence, bioaccumulation, and toxicological effects led to increasing regulatory restrictions.
Many Polybrominated benzoate ester formulations are now considered legacy chemicals, with their production and use being phased out or heavily restricted under environmental safety frameworks such as the Stockholm Convention on Persistent Organic Pollutants (POPs) and national regulations in the EU, U.S., and other regions.
As a result, the current Polybrominated benzoate ester market is shrinking, with demand declining sharply in regulated markets and limited primarily to countries where bans have not been fully implemented.
At the same time, the regulatory pressure has stimulated market growth for safer halogen-free flame retardants such as phosphorus- and nitrogen-based alternatives, which are gaining market share due to their lower environmental impact and compliance with green chemistry standards.
Overall, the outlook for Polybrominated benzoate esters is negative in terms of market expansion, with their relevance today lying mainly in environmental monitoring, waste management, and regulatory compliance, rather than new industrial applications.
Uses of Polybrominated Benzoate Ester:
Polybrominated benzoate esters have been widely used as additive-type flame retardants in a variety of consumer and industrial products due to their high bromine content and strong thermal stability.
They are incorporated into plastics, polyurethane foams, textiles, adhesives, and coatings to reduce flammability by releasing bromine radicals that suppress ignition and slow flame propagation.
Polybrominated benzoate esters were particularly common in electronic equipment housings, building insulation, upholstery, and wire/cable coatings, where compliance with strict fire safety standards was essential.
Their compatibility with polymer matrices also made them attractive for use in construction materials, automotive interiors, and furniture foams.
Beyond consumer products, Polybrominated benzoate esters have also been used in specialized industrial resins and surface treatments to enhance fire resistance.
However, due to their persistence, bioaccumulation, and potential toxicological effects, many of these uses have been restricted or phased out in favor of safer halogen-free flame retardant alternatives, though they may still be encountered in older products and in regions with less stringent regulations.
Polybrominated benzoate ester has been used as a substitute ingredient for polybrominated flame retardants (PBDEs) in flexible polyurethane foam.
These materials are typically found in consumer products such as upholstered furniture, auto cushions, and baby products, and remain in products containing recycled polyurethane foam.
Polybrominated benzoate ester and TBPH make up about 50% of the widely used flame retardant mixture Firemaster 550.
Benefits of Polybrominated Benzoate Ester:
Polybrominated benzoate esters provided significant benefits in their period of widespread industrial use, primarily due to their effectiveness as flame-retardant additives.
Their high bromine content gave them the ability to suppress ignition and slow down flame propagation, which greatly improved fire safety in plastics, foams, textiles, and electronic housings.
One of their key advantages was compatibility with a wide range of polymer systems — including polyurethane, polystyrene, and thermoplastic resins — allowing manufacturers to enhance fire resistance without compromising material performance.
They also offered good thermal stability and durability, meaning that treated materials could maintain long-term flame-retardant properties under normal use conditions.
In consumer safety terms, Polybrominated benzoate esters contributed to reducing the risk of fires in building insulation, furniture, automotive interiors, and electronic products, which made them attractive to manufacturers facing increasingly strict fire regulations in the late 20th century.
While their environmental and health concerns have since overshadowed these advantages, the historical benefit of Polybrominated benzoate esters was their ability to deliver cost-effective, reliable, and efficient flame retardancy in a broad spectrum of industrial and consumer applications.
Production of Polybrominated Benzoate Ester:
Polybrominated benzoate esters are produced through the esterification of brominated benzoic acids with suitable alcohols, or alternatively by the bromination of benzoate esters under controlled conditions.
In one route, benzoic acid is first subjected to electrophilic aromatic substitution with bromine in the presence of a Lewis acid catalyst (such as iron or aluminum halides) to yield polybrominated benzoic acids. These highly brominated intermediates are then reacted with alcohols (e.g., methanol, butanol, or higher-chain alcohols) in the presence of strong acid catalysts like sulfuric acid or p-toluenesulfonic acid, forming Polybrominated benzoate esters. In another industrial pathway, preformed benzoate esters are brominated directly with elemental bromine or bromine donors (e.g., N-bromosuccinimide), leading to multiple bromine substitutions on the aromatic ring.
Once synthesized, the crude product is purified through washing, neutralization, and distillation or recrystallization to remove residual bromine, acid catalysts, and unreacted intermediates. The resulting compounds are generally obtained as viscous oils or crystalline solids, depending on the degree of bromination and the ester substituent. Industrial production emphasizes controlling the degree of bromination (di-, tri-, tetra-, or higher substituted benzoate esters), since this directly influences flame-retardant efficiency, compatibility with polymers, and stability.
Historically, production of Polybrominated benzoate esters was concentrated in regions with strong bromine chemical industries, such as the U.S., Europe, and later East Asia, but declining demand and environmental restrictions have significantly reduced large-scale manufacturing. Today, their production is largely limited, with emphasis shifting toward alternative halogen-free flame retardants due to regulatory pressures.
Synthesis of Polybrominated Benzoate Ester:
Polybrominated benzoate esters are typically synthesized by first brominating benzoic acid or its esters through electrophilic substitution with elemental bromine in the presence of a Lewis acid catalyst such as iron(III) bromide, producing polybrominated benzoic acids.
These intermediates are then converted into esters either by direct esterification with alcohols under acidic, dehydrating conditions, or more cleanly by acid chloride formation with thionyl chloride followed by alcohol substitution.
An alternative route involves bromination of preformed benzoate esters, allowing control over substitution by adjusting bromine equivalents and reaction conditions.
The final products are obtained as viscous oils or crystalline solids, depending on the degree of bromination and the alcohol used.
Careful purification by washing, neutralization, and distillation or recrystallization is required to remove residual bromine and by-products.
This two-step sequence—**controlled bromination followed by esterification—**is the standard industrial method for producing Polybrominated benzoate esters used as flame-retardant additives.
History of Polybrominated Benzoate Ester:
The history of Polybrominated benzoate esters is tied to the development of brominated flame retardants (BFRs) during the mid-20th century, when growing use of synthetic polymers in consumer products created a strong need for additives that could reduce flammability.
Polybrominated benzoate esters, along with related compounds such as tetrabromobenzoate esters and polybromodiphenyl ethers (PBDEs), emerged in the 1960s–1970s as effective, inexpensive flame retardants for plastics, foams, textiles, and electronics.
They were valued for their high bromine content, thermal stability, and compatibility with polymer matrices, which allowed manufacturers to meet increasingly strict fire safety standards.
However, by the late 20th century, research began to reveal that Polybrominated benzoate esters, like other brominated flame retardants, were persistent, bioaccumulative, and potentially toxic, raising concerns about their environmental and health impacts.
Detection of Polybrominated benzoate esters in wildlife, sediments, and even human tissues led to greater scrutiny in the 1990s and 2000s, prompting regulatory reviews.
Today, Polybrominated benzoate esters are considered part of the legacy group of flame retardants being phased out or restricted in many regions under chemical safety frameworks such as the Stockholm Convention, with research shifting toward monitoring their presence in the environment and replacing them with safer halogen-free alternatives.
Handling and Storage of Polybrominated Benzoate Ester:
Handle in well-ventilated areas; avoid inhalation of dusts, mists, or vapors and prevent skin or eye contact.
Do not eat, drink, or smoke when handling.
Store in tightly closed containers in a cool, dry, well-ventilated location.
Keep away from strong oxidizers, acids, and bases to prevent decomposition.
Because Polybrominated benzoate esters are persistent and bioaccumulative, storage areas should be designed to prevent environmental release.
Stability and Reactivity of Polybrominated Benzoate Ester:
Stability:
Generally stable under normal handling and storage conditions.
Reactivity:
Inert toward most materials; may slowly hydrolyze under strongly acidic or basic conditions.
Decomposition Products:
Toxic fumes including hydrogen bromide (HBr) and brominated aromatic compounds when heated to decomposition.
Incompatibilities:
Strong oxidizing agents, reducing agents, strong acids, and strong bases.
First Aid Measures of Polybrominated Benzoate Ester:
Inhalation:
Move exposed individual to fresh air.
Provide oxygen if breathing is difficult.
Seek medical attention if symptoms persist.
Skin Contact:
Remove contaminated clothing.
Wash skin thoroughly with soap and water.
Seek medical help if irritation occurs.
Eye Contact:
Rinse cautiously with water for at least 15 minutes, holding eyelids open.
Obtain medical attention if irritation persists.
Ingestion:
Rinse mouth with water.
Do not induce vomiting.
Get immediate medical attention.
Firefighting Measures of Polybrominated Benzoate Ester:
Suitable Extinguishing Media:
Use foam, dry chemical powder, or carbon dioxide.
Water spray can be used to cool exposed containers.
Hazards from Combustion:
Burning Polybrominated benzoate esters may release hydrogen bromide, carbon monoxide, carbon dioxide, and toxic brominated compounds.
Protective Equipment for Firefighters:
Firefighters should wear self-contained breathing apparatus (SCBA) and full protective gear.
Accidental Release Measures of Polybrominated Benzoate Ester:
Personal Precautions:
Evacuate unnecessary personnel.
Wear gloves, goggles, protective clothing, and a respirator if needed.
Ensure good ventilation.
Environmental Precautions:
Prevent entry into sewers, waterways, or soil — Polybrominated benzoate esters are persistent environmental pollutants.
Cleanup Methods:
Absorb spill with inert material (sand, earth, vermiculite).
Collect in sealed containers for proper disposal as hazardous waste.
Wash spill area with detergent and water after cleanup.
Exposure Controls / Personal Protective Equipment of Polybrominated Benzoate Ester:
Engineering Controls:
Use fume hoods or local exhaust ventilation to minimize airborne concentrations.
Respiratory Protection:
Use NIOSH-approved respirator if exposure limits are exceeded.
Skin Protection:
Chemical-resistant gloves (nitrile, neoprene) and protective clothing.
Eye Protection:
Safety goggles or face shield.
Hygiene Measures:
Wash hands, face, and clothing thoroughly after handling.
Avoid prolonged or repeated exposure.
Identifiers of Polybrominated Benzoate Ester:
Chemical Name: Polybrominated benzoate esters
Common Abbreviation: PBBE
Chemical Class: Brominated aromatic ester; organobromine flame retardant
Representative Compound (EH-TBB)
Molecular Formula: C₁₅H₁₆Br₄O₂
Molecular Weight: 549.91 g/mol
Structure: Benzene ring substituted with four bromine atoms, esterified with 2-ethylhexanol
Appearance: Pale yellow to viscous liquid (depending on purity and isomer content)
CAS Number: 183658-27-7
PubChem CID: 9853651 (EH-TBB)
ChemSpider ID: 8029856
HS Code: 290930 (aromatic esters, including brominated esters)
UN Number (Transport): Not specifically assigned; classified under hazardous organic bromine compounds when transported
InChI: InChI=1S/C15H16Br4O2/c1-2-5-11(6-3-1)9-12(7-4-8-13(16,17)18)21-15(20)10-14(19)22-15/h1,3,7,9-10H,2,4,5-6,8H2
InChI Key: JIPVTKUBTNVVKH-UHFFFAOYSA-N
SMILES: CCCCC(CC)COC(=O)C1=C(C=CC(=C1Br)Br)Br
Molecular Formula: C₁₅H₁₆Br₄O₂
Molar Mass: 549.91 g/mol
Appearance: Pale yellow, viscous liquid
Melting Point: < –20 °C (liquid at room temperature)
Boiling Point: > 350 °C (decomposes)
Solubility: Practically insoluble in water; soluble in organic solvents (acetone, toluene, alcohols)
CAS Number (EH-TBB): 183658-27-7
CAS Range (class): Covers multiple esters; some mixtures reported under different CAS registry entries
PubChem CID (EH-TBB): 9853651
ChemSpider ID (EH-TBB): 8029856
HS Code: 290930 (Aromatic esters, including brominated)
InChI: InChI=1S/C15H16Br4O2/c1-3-5-12(6-4-2)7-9-21-15(20)10-8-11(16)13(17)14(18)19-10/h8,12H,3-7,9H2,1-2H3
InChI Key: JIPVTKUBTNVVKH-UHFFFAOYSA-N
SMILES: CCCCCC(C)COC(=O)C1=C(C(=C(C=C1Br)Br)Br)Br
Properties of Polybrominated Benzoate Ester:
Boiling point: 477.5±40.0 °C(Predicted)
Density: 1.785±0.06 g/cm3(Predicted)
Storage temp.: Sealed in dry,Room Temperature
Solubility: Chloroform, DMSO, Methanol (Slightly)
Form: Oil
Color: Clear Colourless to Pale Yellow
Stability: Light sensitive
EPA Substance Registry System: Tetrabromobenzoate ester composition (183658-27-7)
Appearance: Generally viscous liquids or oily semi-solids; colorless to pale yellow.
Odor: Mild or nearly odorless.
Density: 1.6 – 1.8 g/cm³ (EH-TBB ≈ 1.70 g/cm³ at 25 °C).
Molecular Weight: Varies depending on alkyl ester group and bromination (EH-TBB: 549.91 g/mol).
Melting Point: Typically < –20 °C (EH-TBB remains liquid at room temperature).
Boiling Point: > 350 °C (thermal decomposition before boiling).
Viscosity: Moderate to high, depending on ester chain length.
Refractive Index: nᴅ²⁰ ≈ 1.55–1.60.
Chemical Class: Brominated aromatic esters (organobromine compounds).
Functional Groups: Benzene ring with multiple bromine substituents + ester bond linking to alkyl chain.
Solubility:
Water: Practically insoluble (< 0.1 mg/L).
Organic solvents: Soluble in alcohols, ethers, ketones, hydrocarbons (e.g., toluene, acetone).
Partition Coefficient (log Kₒw): High (~6–8), indicating strong hydrophobicity and bioaccumulation potential.
Vapor Pressure: Very low (< 1 × 10⁻⁷ mmHg at 25 °C) → low volatility.
Henry’s Law Constant: Low → not easily volatilized from water.
