2-Bromobutyric Acid: A Straightforward Look at Properties, Structure, and Uses

What Is 2-Bromobutyric Acid?

2-Bromobutyric acid stands out in many chemical labs, research centers, and manufacturing lines as a reliable raw material for organic synthesis. This compound, with the formula C4H7BrO2, carries a fairly simple molecular structure: four carbon atoms, seven hydrogen atoms, one bromine atom, and two oxygen atoms. I’ve reached for bottles labeled 2-bromobutyric acid while working on esterification and amino acid analogs, and what usually strikes me first is the variety of forms this compound can take—it can show up as a white to off-white solid, a powder, or sometimes as clear colorless crystals, each form lending itself to different handling experiences. More than one researcher in a crowded university lab has tried to pour it from bulk flakes into a beaker, only to find that static can get those fine crystals everywhere if you aren’t careful.

Physical Properties and Specifications

2-Bromobutyric acid offers a melting point around 49–52 °C, which means it’s solid at room temperature but melts pretty easily in a warm environment. Its density sits close to 1.6 g/cm³, making it heavier than water but easy to weigh and transfer in standard glassware. The pure solid carries a slight acidic smell—sharp but less biting than some of its chlorinated cousins. As you might expect from its chemical makeup, it dissolves in water to some extent, but mixes much better in organic solvents like ethanol, methanol, and ether, which makes it handy for many reaction setups. In its powdered form, it flows well for weighing out small quantities on an analytical balance, though the fine grain size can sometimes lead to limited dusting—gloves and fume hoods become more than just a suggestion here.

Chemical Structure and Molecular Details

2-Bromobutyric acid belongs to the class of α-halo acids—a group famous for their utility in building more complex molecules. The structure includes a bromine atom attached to the second carbon of the butyric acid chain, which creates a reactive center ideal for substitution and elimination reactions. With a molecular weight just over 167 g/mol, it presents an accessible starting point for synthesis work, whether you’re aiming to add a side chain to a medicinal molecule or craft a custom reagent for asymmetric synthesis. The placement of the bromine influences the electron distribution along the carbon chain, making the molecule both a raw material and a mild irritant—always a reminder to take the right safety steps.

Handling, Storage, and Safety

Anyone who has opened a fresh bottle of 2-bromobutyric acid notices immediately how important safety gear becomes. Goggles and gloves matter—not just for splashes or dust, but for the subtle skin irritation that can sneak up if you’re careless. This compound ranks as hazardous due to both its pungency and its reactivity; inhaling the dust or getting drops on open skin introduces risks most lab professionals seek to avoid. The material needs to stay in tightly closed containers, in cool and dry spaces away from incompatible chemicals like strong bases or oxidizers. In my own storeroom, acids like this sit on a dedicated shelf with easy access to spill control kits.

Forms and Typical Uses

Depending on the intended process, 2-bromobutyric acid can reach a user as powder, flakes, crystalline solids, or sometimes as a solution in a non-reactive solvent. Solid material often finds application in pharmaceutical synthesis—especially in the building of chiral drugs, where the brominated position lets chemists tweak molecule shapes. I’ve seen bulk shipments of crystalline 2-bromobutyric acid arrive in sealed bags destined for custom syntheses, especially where a highly specific reaction pathway calls for an α-halo acid. Some companies require tight quality control on the raw material, checking its density and melting point before they even start the next synthetic run. On the industrial chemistry side of things, this molecule serves as a bridge to other complex molecules, where the bromine atom gets swapped out in a planned sequence of transformations.

Regulatory Info and International Trade

Getting a shipment of 2-bromobutyric acid cleared through customs usually means referencing the HS Code—specifically 2915900090, which covers a range of halogenated carboxylic acids. The paperwork needs precise identification for material safety data, with clear marking on the “hazardous” sections. Packaging must stand up to rough transport conditions without leaks because minor spills can trigger not just chemical exposure, but real delays or fines with authorities. Packing slips often record net weight, form (flakes, powder, solid, pearls, crystal, or liquid), and even the density, so customs officers can match the incoming goods to the expected specs.

Potential Health and Environmental Concerns

Many chemists, myself included, keep in mind the toxicology profile of 2-bromobutyric acid. Exposure does more than just cause mild discomfort—prolonged contact or inhalation brings risks of respiratory irritation, headaches, or mild nausea. The material counts as harmful; waste needs neutralization (often with basic solutions followed by local regulations for disposal). Spills in the storeroom often mean full cleanup gear, because this compound can seep into flooring or react with incompatible materials. Disposing of it down standard drains, without proper neutralization, can cause trouble for municipal water supplies, as brominated organics often resist breakdown and can persist in the environment.

Looking at Safer and More Efficient Practices

Not every application requires broad changes, but new guidelines and technologies keep raising the bar for safe handling. Spill containment systems and updated analytical balances minimize dust and reduce exposure. As more companies move toward greener chemistry, alternatives with lower toxicity and faster breakdown in the environment see increased research. Researchers at several institutes continue to hunt for more sustainable paths to produce and use halogenated acids, aiming to reduce both environmental and occupational hazards. In the meantime, 2-bromobutyric acid stays in use because it works—helping scientists and manufacturers reach goals that matter both in research and the marketplace.