2-Chloro-3-Methylthiophene is an organosulfur compound with importance in chemical synthesis. This aromatic molecule forms part of the thiophene family, recognized for its five-membered rings containing both sulfur and carbon atoms. The structure features a methyl group attached to the third carbon on the ring, and a chlorine atom bonded to the second carbon. Chemists use this compound as an intermediate, especially in pharmaceuticals and agrochemicals. The chemical formula, C5H5ClS, shows this material holds a single chlorine atom, five carbons, five hydrogens, and a sulfur atom. The molecular weight comes in at around 132.61 g/mol.
Samples of 2-Chloro-3-Methylthiophene often appear as a colorless to pale yellow liquid, though some batches present in slightly off-clear forms depending on storage. This liquid gives off a sharp, sometimes slightly sweet odor, typical for chlorinated thiophenes. Density generally measures around 1.16 g/cm3 at room temperature. Though the pure form shows as a stable liquid in ambient conditions, prolonged exposure in open air tends to introduce mild oxidative changes, so sealed containers keep the material in good condition. Other physical forms, such as solid, flakes, powder, or crystals, seldom appear under standard conditions, since the melting point usually stays below room temperature. Large-scale suppliers distribute this compound in liter bottles or drums, with purity typically verified by gas chromatography.
The molecule’s chlorinated site opens up a variety of chemical reactions, especially halogen-metal exchanges and nucleophilic substitutions, often leading to more complex thiophene derivatives. Its methyl group aids selective alkylation chemistry. As an aromatic, the compound resists rapid degradation, making it valuable for stepwise synthesis in labs and plants. It dissolves in most organic solvents, including ether, dichloromethane, and toluene. Water solubility remains very limited. The boiling point hovers near 160°C, providing manageable volatility for many laboratory and production operations. Reactivity trends stay consistent with other chlorinated aromatics; strong bases or nucleophiles react at the chloro-substituted site under the right conditions.
2-Chloro-3-Methylthiophene enters the manufacturing sector as a raw material for several advanced chemicals. In drug research, it helps build cores for active pharmaceutical ingredients and appears in the synthesis chain of several fungicides, herbicides, and specialized materials. The unique substitution pattern of the chlorine and methyl groups allows chemists to tailor new compounds for performance or biological activity. Sourcing relies on early-stage reactions involving methythiophenes and chlorinating agents. The feedstocks usually undergo tight quality control, with trace impurities monitored to prevent any downstream reaction issues.
From a safety perspective, 2-Chloro-3-Methylthiophene counts as a hazardous chemical, since strong evidence links organochlorine vapors and skin contact with irritation and toxic effects. Proper PPE stands as a baseline requirement: gloves, goggles, and appropriate ventilation. Because of its volatility, spills quickly release vapors. Eye and skin exposure can trigger discomfort, redness, or more severe reactions in sensitive individuals. If inhaled at high concentrations, the compound has the potential to affect respiratory function, so fume hoods or local exhaust systems are a must in handling areas. Chronic exposure data stays limited, yet the precautionary principle recommends limiting any chance of prolonged inhalation or direct tissue contact. Waste disposal must follow local hazardous waste protocols, often managed through incineration or thoroughly controlled chemical treatment. Always refer to the Safety Data Sheet (SDS) for the latest handling, storage, and disposal guidelines.
Most suppliers set minimum purity at 98%, with traces of related thiophenes, halides, or unreacted precursors controlled to below 1% each. Water content generally stays under 0.5%, as measured by Karl Fischer titration. The HS Code for international shipping, classification, and customs documentation lands at 2934.99—the broader category for organo-sulfur compounds. Storage in sealed amber bottles keeps the compound protected from both light and air. Reaction scale, packaging form (liter jugs for labs, metal canisters for industry), and shipping method require specification during ordering, to maintain stability and prevent leaks during transit. Certification of analysis (CoA) and compliance with shipping regulations such as IATA, IMDG, or DOT confirm adherence to international safety rules. Some regions impose special tracking for chlorinated intermediates, reflecting concern about environmental effects and safe uses.
Structurally, 2-Chloro-3-Methylthiophene expresses a planar geometry, confirmed by NMR and X-ray crystallography. The electron-withdrawing chlorine at the ortho position draws attention in spectroscopic work; it shifts NMR signals and influences reactivity in synthesis planning. Infrared spectra show peaks matching aromatic C-H and thiophene S atoms, with an added distinctive C-Cl fingerprint region. Quality control departments rely heavily on GC-MS or HPLC chromatograms for purity assurance and quantification of any trace byproducts left from production. Each analytical result links with batch numbers for traceability.
Given global attention on chemical hazards, responsible sourcing and lifecycle tracking step up as real priorities. Large-scale manufacturers look for feedstocks and processes that keep emissions, hazardous byproducts, and waste streams to a minimum. From experience, good documentation and transparency regarding origin and environmental controls in the supply chain reinforce trust and long-term partnerships with customers. Strong communication between suppliers and buyers supports accurate specification, shipment integrity, and swift response should handling or shipping incidents occur. The industry continues to invest in greener processes and alternatives, given the public and regulatory focus on sustainability and chemical safety.
