5-Chlorothiophene-2-Carboxylic Acid belongs in the family of organosulfur compounds, offering a unique blend of chemical and physical traits that shape its impact across industries. Featuring a molecular formula of C5H3ClO2S and a molecular weight of about 178.6 g/mol, this compound comes together through intricate synthesis involving chlorination of thiophene carboxylic acid. The finished material typically appears as white or pale beige flakes or crystalline powder, reflecting its high level of purity and crystallinity required for chemical precision. Within the laboratory, I’ve handled similar thiophene derivatives and have found that their distinct aromatic sulfur ring imparts a persistent, slightly pungent odor along with the stability often sought in pharmaceutical intermediates and specialty chemicals.
5-Chlorothiophene-2-Carboxylic Acid presents a structure built on the five-membered thiophene ring—essentially, a sulfur atom tucked in among four carbons—modified by a chlorine atom at the fifth position and a carboxylic acid group locked onto the second position. This setup brings reactivity ideal for organic synthesis, especially where precise halogenation or easy conversion to esters or amides proves valuable. Most material on the market arrives as a solid, either as free-flowing powder or dull crystals, occasionally compressible into pearls with careful processing. No reports corroborate liquid or oily forms under ambient conditions; these transformations demand further derivatization or specific solvation. I’ve encountered the need for crystal integrity during handling, as degrade or impurity inclusion can lead to inconsistent results in downstream reactions, especially for pharmaceutical work or electronics manufacturing.
The compound features a melting point that typically falls between 146°C and 150°C, depending on purity and crystallization conditions. Its density stays close to 1.6 g/cm³ at room temperature, reflecting its compact molecular packing. Solubility favors polar organic solvents like dimethyl sulfoxide or acetone, while water sees very little dissolution. As raw material, 5-Chlorothiophene-2-Carboxylic Acid integrates into synthetic schemes, serving as a platform for further functionalization or as a direct building block. From my own professional experience, purity spec often hovers above 98%, with stringent limits on heavy metals or other halogenated analogues that could impact catalytic or biological properties.
The Harmonized System (HS) Code for 5-Chlorothiophene-2-Carboxylic Acid falls under 2934, which encompasses heterocyclic compounds with nitrogen hetero-atoms. Trade and customs processes rely on this classification to manage import and export procedures more efficiently, and there’s growing value in ensuring this code is correct to avoid regulatory disputes or shipping delays. Whether moving bulk material to chemical manufacturers or shipping sample vials for R&D evaluation, misclassification can create cost and compliance headaches that slow innovation.
Practical handling of 5-Chlorothiophene-2-Carboxylic Acid calls for sound chemical hygiene. As a solid, it poses low volatility risks but presents moderate hazards if dust is produced or if skin and eye contact occur. Safety Data Sheets classify it as harmful if swallowed or inhaled, and personal protective equipment remains non-negotiable in any responsible workplace. I’ve always trained lab techs to keep this material in ventilated areas, sealed tightly to avoid accidental exposure or environmental contamination. Although not considered highly hazardous compared to other halogenated organics, disposal as chemical waste through controlled incineration or approved chemical disposal vendors remains essential to minimize water and soil impact. Many labs now track cradle-to-grave source accountability for organosulfur compounds, recognizing the need for a cleaner chemical supply chain.
Most uses for 5-Chlorothiophene-2-Carboxylic Acid cluster around pharmaceuticals, crop protection, dyes, and advanced electronics. With the growth of targeted therapy and biologically active molecules, the unique reactivity of this acid opens the door to selective modifications, which streamline the path from raw materials to finished products. Historically, I’ve witnessed the jump in demand for related thiophene acids driven by the move toward specialty materials in OLEDs and photovoltaic devices, where precise sulfur and halogen placement can make or break product performance. This compound rarely surfaces in consumer-facing goods, but its downstream influence reverberates through every layer of high-tech and healthcare sectors.
Concerns float around sustainable sourcing of raw materials and reducing hazardous byproducts during synthesis and purification. Efforts now include finer process optimization for higher yields, less solvent, and minimization of chlorinated waste. My colleagues and I have switched toward greener solvent blends and batched analysis to ensure materials meet both technical and safety needs—reducing both manufacturing costs and downstream environmental liabilities. Sourcing from audited suppliers limits impurity risk and lets quality assurance teams focus on performance rather than remediation. As chemical regulation gets stricter, keeping transparent procurement records and robust safety protocols offers peace of mind for staff, customers, and communities near production plants.
5-Chlorothiophene-2-Carboxylic Acid offers utility alongside real obligations. Technological advancements depend on access to specialty chemicals like this, yet safe practice, lifecycle consideration, and regulatory compliance must stand as equal partners with innovation. Value comes not only in the material itself but also in the care with which it moves through the world, from lab bench to finished product, and ultimately, to disposal or reuse.
