4-Bromotoluene: A Closer Look at an Industrial Chemical

What is 4-Bromotoluene?

4-Bromotoluene, known among chemists for its role as both a building block and a precursor, serves a crucial function in the world of organic synthesis. This compound, with the formula C₇H₇Br, brings a toluene ring substituted with a bromine atom at the para position (often referred to as the 4-position). The molecular mass reaches 171.04 g/mol. Its chemical structure reveals a benzene ring bearing a methyl group directly opposite to the bromine substituent, shaping its unique set of properties and reactivity. From personal observations in the lab, the compound’s strong, almost pungent odor and crystalline form stand out and often leave a lasting impression on those handling raw materials for the first time.

Physical Properties and Appearance

On inspection, 4-Bromotoluene typically presents as colorless to pale yellow crystals or flakes, especially when protected from light and moisture. It tends to show up in various forms, from powder and solid crystalline chunks to smaller flakes that can sometimes resemble pearls under specific handling conditions. At room temperature, its solid nature dominates, but it can also be occasionally found as a dense liquid in high purity samples or when nearing its melting point of 44–47°C. Its boiling point clocks in at around 184–186°C, a feature that often draws a line between safe storage and unwanted volatility. Having worked with the material in glassware, it feels notable that it neither dissolves easily in water nor undergoes rapid degradation in typical laboratory atmospheres.

Density, Solution, and Specification Details

Measurements pin the density of 4-Bromotoluene at approximately 1.41 g/cm³ at 20°C. This relatively high density compared to other hydrocarbons might surprise those used to lighter organics, but the presence of bromine as a heavy atom explains this property. As for solubility, its low affinity for water reinforces the need for organic solvents like ether, chloroform, or benzene for dissolution—something anyone in a chemical lab quickly learns when preparing solutions for further reactions. When handled as a raw material, purchases often come with an assay specification nearing 99%, ticking off requirements for applications in pharmaceutical intermediates, agrochemical research, and specialty material synthesis. In processes where precise density matters, like certain analytical contexts or when working with liquids by liter volume, the strict data on physical constants becomes not just useful, but essential for compliance and quality control.

Structure and Molecular Property Insights

The structure of 4-Bromotoluene confers a suite of useful reactivity, especially through its para-bromine. This position opens up cleaner reactions for cross-coupling chemistry such as Suzuki or Heck reactions. In my own work, running these couplings becomes far more predictable and effective due to the electronic effects governed by this molecular arrangement. The bromine atom offers a site ready for nucleophilic substitution, while the methyl group yields extra stability and slight electron donation, often enhancing certain material properties in end products. Looking at its specification details, users can expect a clear melting point (45°C), boiling range (184–186°C), and a refractive index set at around 1.561, data points indispensable for confirming material identity and consistency across batches.

HS Code and Market Relevance

Trade and regulatory frameworks label 4-Bromotoluene under the HS Code 29036990, classifying it with halogenated derivatives of aromatic hydrocarbons. This becomes important for manufacturers and traders handling imports and exports, ensuring tariffs, transportation, and safety documentation remain accurate and compliant. In the global market, this HS Code helps buyers and customs officials track raw materials central to sectors from dyes and electronics to pharmaceuticals. Within supply chains, such a code acts as a common language, linking upstream chemical production and downstream product development, ensuring the right chemical arrives at the proper facility and meets the specified standards.

Hazardous, Harmful, and Safety Considerations

While 4-Bromotoluene doesn’t top the charts for acute toxicity, its handling mandates caution and respect. Long periods of exposure to its vapors or direct contact with skin can cause irritation and, in some rare cases, sensitization. Any laboratory technician who’s spent hours over a fume hood can attest to the distinct irritation that comes with careless use. Material safety data sheets classify this chemical as a moderate irritant, underlining the value of gloves, goggles, and proper ventilation. On larger scales or in raw material form, accidental spills or release into the environment heighten the risk to workers and nearby ecosystems, which sets rules for storage, disposal, and emergency procedures. Local and international regulations set storage guidelines, limiting exposure and potential hazardous outcomes, reinforcing the need for safe handling habits from the outset.

Role as a Raw Material and in Production

Outside lab benches, 4-Bromotoluene finds its main calling as a raw material in the creation of more advanced chemicals. It feeds directly into syntheses of pharmaceuticals, agricultural chemicals, functional polymers, and specialty dyes. With methyl and bromine in tandem, chemists can push forward into new compounds with desired reactivity for crop protection, medical treatments, or advanced manufacturing processes. First-time users sometimes overlook its value until they see its impact on reaction yields and downstream efficiency. Manufacturers focus on purity, physical consistency, and reliable packaging—crystal, powder, solid, or even liquid—depending on customer requirements and process specifications. Working with this compound, it’s clear that its importance stretches from basic study all the way to finished goods, connecting research, industry, and regulated commerce in a single chemical thread.