2-Thienylacetic acid reveals the interesting chemistry of aromatic carboxylic acids joined to a thiophene ring. Its molecular formula is C6H6O2S, pointing to a backbone built from a five-membered aromatic ring containing sulfur, the thiophene, and an acetic acid group. Most laboratories interacting with organic chemicals know this compound for its manageable solid form, pale to light brown in color, often seen as flakes, powder, or fine crystalline material. No matter the specific batch, the unmistakable faint aromatic odor travels with it, a reminder of the volatile nature of many thiophene-linked chemicals. The HS Code for 2-Thienylacetic Acid classifies it as 2934999099, marking it for international trade under organic chemicals.
Looking at the structural formula, a thiophene ring sits directly attached to an acetic acid side chain, which tips the scale toward increased solubility in polar organic solvents and moderate solubility in water. Measured density lands near 1.325 g/cm3, a typical value for small sulfur-containing aromatics. The melting range usually hovers around 62-65°C, giving chemists flexibility to use this compound in conditions that require moderate thermal tolerance. Inspecting a sample held under good laboratory lighting, one will notice the flakes or small clusters can clump together, but crumble easily under pressure to yield a loose powder.
Pure 2-Thienylacetic Acid arrives as a stable solid under ambient room conditions. Most often, material is shipped as crystalline powder or granular flakes. Exposure to moisture in the air can make these flakes clump, but a gentle tap restores the powdery texture. The density clocks in at approximately 1.325 g/cm3–think of this as slightly denser than water, but lighter than most heavy metals or inorganic salts. The crystalline particles scatter light unevenly, so a glass vial will let some light through, but not enough to read fine print behind it. No pearls or liquid forms appear in typical stocks, and conversion to solution typically requires ethanol or DMSO as a solvent, due to only moderate water solubility.
Organic chemists value 2-Thienylacetic Acid as a reliable raw material for downstream synthesis. The thiophene ring remains intact under many mild reaction conditions, but the acetic acid group proves reactive, easily engaging in coupling, condensation, or esterification reactions. The presence of sulfur in the ring subtly influences its electron density, which can make certain substitutions easier compared to benzene-based relatives. Heating above its melting point in open air risks some decomposition, so careful temperature control is important during any chemical process that draws on this compound.
2-Thienylacetic Acid finds its spot as an intermediate in pharmaceutical, agricultural, and fine chemical manufacturing. Its unique structure opens the door for synthesizing thiophene-bearing drugs, dyes, and specialty polymers. As with many organic acids, risk of harm comes from inhalation of dust or accidental contact with skin or eyes. Material Safety Data Sheets rate this compound as harmful if swallowed and potentially irritating by contact or inhalation. Effective protocols call for gloves, goggles, and a calibrated fume extractor to handle dust. Spills clean up with a lab vacuum and immediate bagging of residue, since fine powders can cling to surfaces.
Anyone who works with aromatic acids learns to respect proper storage. 2-Thienylacetic Acid keeps well in tightly-sealed glass or high-density polyethylene containers, stored away from heat and direct sunlight. Keeping workspaces low in humidity goes a long way toward preserving the acid’s powdery consistency. For global trade and transport, the HS Code 2934999099 tracks shipments for customs and trade compliance. Disposal in local chemical waste streams reduces environmental risk. Acidic, sulfur-containing organics should never go down laboratory drains; instead, they need professional handling as hazardous waste, with documentation showing compliance. This lowers the risk of fire, chemical burns, and downstream water pollution.
The molecular mass of 2-Thienylacetic Acid registers at 142.18 g/mol. Its SMILES notation–CC(=O)C1=CC=CS1–captures the entire chemical framework in a line, supporting database searching and digital inventory. X-ray crystallography reveals the thiophene and acetic acid groups orient at a slight angle, giving the molecule flexibility in reactions but helping it to pack nicely in crystalline form. While the molecule doesn’t glow under UV, pure crystals refract light along regular facets, sometimes sparkling faintly in good light. It resists slow oxidation in open air, but impurities can darken its color after extended exposure, especially in sunlight or humid storage.
Any lab seeking new drugs or advanced polymers finds value in 2-Thienylacetic Acid. The compound’s structure bridges aromaticity and reactivity, allowing for creative design of molecules that need an aromatic backbone with some tolerance to chemical processing. Lower toxicity compared to several benzene-bonded analogues makes it a more accessible choice, though full PPE remains standard. Some industrial uses convert this acid into esters or amides, both classes appearing in specialty solvents, advanced lubricants, or ligands for metal catalysts. Safety teams note a moderate hazard level, but not on par with acyl chlorides or halogenated relatives.
Challenges in handling 2-Thienylacetic Acid focus on dust control, exposure risks, and waste stream management. Higher-efficiency fume extractors and closed-system transfer lines at industrial scale reduce contact and inhalation hazards. To boost sustainability, process chemists look for greener solvents for routine dissolution, and many companies push for recycling containers to lessen environmental impact. Research teams examine pathways for converting, neutralizing, or reusing spent acid residues into safer materials or energy, tying the compound’s lifecycle to broader chemical stewardship. Understanding the properties, risks, and opportunities around 2-Thienylacetic Acid gives users a chance to innovate safely while protecting workplace and planet, one small molecule at a time.
