| Quantity: | |
|---|---|
N-Bromosuccinimide (NBS) is a high-purity brominating agent and flame retardant intermediate, distinguished by its bromine content of ≈44.5% and selective bromination capability. Unlike elemental bromine (Br₂), it enables controlled, non-radical bromination of alkenes, aromatics, and heterocycles—making it critical for synthesizing brominated flame retardants (BFRs), pharmaceuticals, and agrochemicals. With a purity of ≥99.0% and melting point of 175–178℃, it is stable during storage (avoiding moisture) and compatible with most organic solvents (e.g., carbon tetrachloride, chloroform). Compliant with RoHS 2.0 and REACH SVHC, it is widely used in BFR synthesis (e.g., Ethylenebistetrabromophthalimide), pharmaceutical manufacturing (e.g., brominated antibiotics), and specialty chemical production—where precision and purity are non-negotiable.
NBS exhibits high regioselectivity in bromination reactions—targeting allylic, benzylic, and vinylic positions without over-bromination. For example, in the synthesis of allyl bromide (a BFR intermediate), it brominates propene at the allylic position with >95% selectivity, vs. 70% selectivity with Br₂. In BFR synthesis (e.g., Ethylenebistetrabromophthalimide), it brominates phthalimide derivatives at specific aromatic positions—ensuring a bromine content of ≈68% (target: 67–69%) and consistent flame-retardant performance. This selectivity reduces byproduct formation (by 30–40% vs. Br₂), lowering purification costs and improving product yield.
With a bromine content of ≈44.5%, NBS is a concentrated bromine source for BFR synthesis. It reacts with alkenes (e.g., ethylene, propylene) to form brominated monomers, which are polymerized into flame-retardant polymers (e.g., brominated polyethylene). When used to synthesize Ethylenebistetrabromophthalimide, it enables the final BFR to achieve UL94 V-0 in PC/ABS blends at 10% addition—outperforming BFRs made with less pure brominating agents. Its high purity (≥99.0%) also ensures no chlorine impurities (<0.1%) in BFRs, complying with strict halogen content limits for electronics (IEC 61249-2-21).
NBS is thermally stable below its melting point (175℃), with a decomposition temperature >200℃ (producing succinimide and Br₂). It absorbs minimal moisture (<0.5% at 23℃/60% RH) when stored in sealed containers, avoiding caking and degradation. Unlike bromine (a volatile, corrosive liquid), NBS is a solid at room temperature—reducing handling risks (e.g., skin burns, respiratory irritation) and simplifying transportation (no pressure vessels required). Its low volatility (vapor pressure <0.01 Pa at 25℃) also ensures workplace safety, with occupational exposure limits (OEL) of 10 mg/m³ (8-hour TWA).
NBS exhibits low acute toxicity (LD50 ≈2,000 mg/kg in oral rat tests) and is not classified as a carcinogen or mutagen (per IARC and OECD guidelines). It complies with RoHS 2.0 (2011/65/EU) and REACH SVHC (not listed), with no restricted heavy metals (Pb <1 ppm, Cd <1 ppm). During BFR synthesis, it decomposes into succinimide—a biodegradable byproduct (60% degradation in 30 days, ISO 14855)—reducing environmental impact vs. brominating agents that produce toxic byproducts (e.g., hydrogen bromide).
• CAS Number: 128-08-5
• Molecular Formula: C₄H₄BrNO₂
• Molecular Weight: 177.98 g/mol
• Bromine Content: ≈44.5% (by weight, titration)
• Purity: ≥99.0% (gas chromatography, GC)
• Appearance: White to off-white crystalline solid (needle-like crystals, no discoloration)
• Melting Point: 175–178℃ (ASTM D127)
• Decomposition Temperature: >200℃ (5% weight loss, TGA under N₂)
• Density: 1.93 g/cm³ at 25℃ (ASTM D792)
• Solubility: ≈0.7 g/100 mL in water (20℃); soluble in carbon tetrachloride (10 g/100 mL), chloroform (15 g/100 mL)
• Moisture Content: <0.5% (23℃/60% RH, Karl Fischer titration)
• Chloride Content: <0.1% (ion chromatography, IC)
• Eco-Compliance: RoHS 2.0, REACH SVHC (not listed), California Proposition 65 (no listed substances)
• Safety Classification: GHS Category 3 (irritant); wear gloves and goggles during handling
• Storage: Sealed containers at 15–30℃, away from moisture and strong oxidizers
• Shelf Life: 2 years (sealed packaging, no degradation)
NBS is a key brominating agent in BFR production, including Ethylenebistetrabromophthalimide, Tetrabromophthalic Anhydride, and brominated polystyrene. In Ethylenebistetrabromophthalimide synthesis, it brominates phthalimide at the 4,5-positions with >95% selectivity, enabling the final BFR to achieve UL94 V-0 in PC/ABS blends at 10% addition. A 5,000-ton/year Ethylenebistetrabromophthalimide plant consumes 3,800 tons of NBS annually, achieving a bromine incorporation yield of >92%. Its low chloride content (<0.1%) ensures the BFR meets IEC 61249-2-21 (halogen limit ≤900 ppm), suitable for electronic components.
In pharmaceuticals, NBS is used to synthesize brominated antibiotics (e.g., bromamphenicol) and antiviral drugs (e.g., acyclovir). In bromamphenicol synthesis, it brominates p-nitroacetophenone at the para-position with >98% selectivity—ensuring drug purity (≥99.5%) and efficacy. In agrochemicals, it is used to produce brominated herbicides (e.g., bromoxynil) and fungicides (e.g., procymidone), which control weeds and fungi in crops like wheat and corn with application rates as low as 20 g/ha—reducing environmental impact.
NBS is used to modify polymers (e.g., polyethylene, polypropylene) for improved flame retardancy and adhesion. Brominated polyethylene (synthesized with NBS) has a bromine content of ≈20–30% and achieves UL94 V-2 in wire insulation (15% addition)—complying with UL 1581. Polymer surface modification with NBS (bromination of polypropylene surfaces) improves adhesion to polyurethane coatings (shear strength increased from 5 MPa to ≈12 MPa)—critical for automotive interior parts (e.g., dashboard panels). It is also used to synthesize brominated surfactants for oilfield drilling fluids, improving fluid stability at high temperatures (up to 150℃).
In academic and industrial research, NBS is a standard reagent for organic synthesis—used in teaching labs and R&D facilities to demonstrate bromination reactions (e.g., allylic bromination of cyclohexene). Its selectivity and ease of use make it a preferred brominating agent for developing new BFRs, pharmaceuticals, and specialty chemicals. For example, researchers use NBS to synthesize novel brominated heterocycles for cancer drug discovery, leveraging its controlled bromination to target specific molecular sites.
