P-Bromonitrobenzene
Zouping Jinxing Chemical Co., Ltd. is one of the leading manufacturers and suppliers of p-bromonitrobenzene in China. If you're going to wholesale bulk p-bromonitrobenzene made in China, welcome to get free sample from our factory. All customized products are with high quality and low price.
Synthetic route
Nitration of bromobenzene (industrial standard): Bromobenzene reacts with mixed acid (HNO₃/H₂SO₄) via dropwise addition at 30–50°C. Since the –Br group is an *ortho*/*para*-directing group (weakly activating), the reaction yields primarily the *para*-isomer along with a small amount of the *ortho*-isomer; the *para*-isomer is isolated via recrystallization from ethanol, achieving a yield of over 80%.
Bromination of nitrobenzene: Nitrobenzene reacts with Br₂/FeBr₃. The –NO₂ group is a strong *meta*-directing group, theoretically yielding the *meta*-isomer as the major product; this is not a suitable method for producing the *para*-isomer and is mentioned only in literature or older processes, as it is uneconomical and generates significant by-products.
Primary Uses
Reduction → *p*-Bromoaniline (4-bromoaniline, CAS 106-40-1): via Fe/HCl, Sn/HCl, or catalytic hydrogenation (Pd/C or Raney Ni); *p*-bromoaniline serves as an intermediate for azo dyes, pharmaceuticals (e.g., LSD1 inhibitors), and pesticides.
SNAr substitution of bromine: rUnder vigorous conditions (such as NaOMe/DMF at high temperatures or liquid ammonia/KNH₂), p-bromonitrobenzene reacts with alkoxides, amines, or phenols to yield p-nitrophenyl ethers or p-nitrodiphenylamines.
Coupling reaction substrate: the bromine site enables Suzuki, Heck, or Buchwald-Hartwig couplings (forming C–C or C–N bonds, with the nitro group available for subsequent reduction); it exhibits higher coupling reactivity than the corresponding chlorinated analog.
Dye/pharmaceutical intermediate: used in the synthesis of brominated azo dyes, quinazoline derivatives, and antibacterial intermediates.
Safety and Toxicology
Toxicity: Harmful if swallowed, in contact with skin, or inhaled (R20/21/22); rapidly absorbed through the skin; can cause methemoglobinemia (cyanosis)-mechanism similar to *p*-chloronitrobenzene, but aryl bromides exhibit higher lipophilicity and faster percutaneous absorption.
Irritation: p-Bromonitrobenzene causes irritation to the eyes, skin, and respiratory tract; GHS classification H302+H315+H319+H341 (suspected of causing genetic defects).
Combustion/Explosion: Combustible solid; decomposes under high heat, releasing HBr, NOₓ, and Br₂ vapors; reacts with strong oxidizing agents, strong reducing agents, and strong bases.
Storage/Transport: UN 3459, Class 6.1, PG III; store in a cool, well-ventilated area in a sealed container, separated from oxidizing agents, reducing agents, and bases; wear dust-proof clothing, organic vapor filter cartridges, and chemical-resistant gloves during handling; avoid alcohol consumption.
FAQ
Q: Toxicity and Occupational Health
A: Primary Hazard: Dermal absorption leading to methemoglobinemia (cyanosis)-a hallmark toxicological effect of nitrobenzene compounds; the nitro group undergoes metabolic reduction, oxidizing hemoglobin to methemoglobin and impairing oxygen-carrying capacity. Acute Effects: Dust or vapors irritate the eyes, respiratory tract, and skin; inhalation causes dizziness and nausea; dermal absorption can lead to cyanosis (bluish discoloration of lips/fingernails) and respiratory distress. Chronic Effects: Long-term exposure may affect the liver and hematopoietic system; some data suggest potential mutagenicity (classified as a mutagen in RTECS). LD₅₀: Moderately toxic via the oral route (in the range of several hundred mg/kg for rodents, though figures vary by source); however, dermal toxicity poses a greater risk than the numerical value alone suggests. Occupational Exposure: No specific Chinese PC-TWA standard exists; control is managed by analogy to the "nitroaromatics and halogenated aromatics" category. Strict control of workshop dust concentrations within the 0.1–1 mg/m³ range is recommended (referencing the stricter limits for nitrobenzenes). GHS Statements: H302 (Harmful if swallowed), H312 (Harmful in contact with skin), H315/H319 (Skin/eye irritation), H331 (Toxic if inhaled), H373 (May cause damage to organs through prolonged or repeated exposure).
Q: Key Points for Handling and Storage
A: Dust control is paramount: conduct operations inside a fume hood; use a scoop or spatula to handle gently and prevent static-induced dust dispersion; implement dust alarms and periodic dust deposition monitoring. PPE: chemical-resistant suits, nitrile or neoprene gloves (replace immediately if damaged), safety goggles, and dust masks (supplied-air respirators when necessary); direct skin contact is strictly prohibited. Storage: store in a sealed, cool, dry, and dark place; keep separate from strong oxidizers (nitrates, peroxides), strong reducing agents, and strong bases; protect against moisture and caking. Spills: collect using wet methods or cover with plastic sheeting before sweeping into a sealed container; do not use air blowers (which disperse dust); dispose of via qualified incineration facilities as halogen- and nitrogen-containing hazardous waste (with flue gas treatment to remove NOx/HBr). Firefighting: use water spray, alcohol-resistant foam, dry chemical powder, or CO₂; thermal decomposition releases HBr, NOx, and CO, requiring firefighters to wear SCBA.
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