5-Chlorovaleryl chloride belongs to the family of organic acid chlorides with the chemical formula C5H8Cl2O. It contains both a chloro group and an acyl chloride group attached to a five-carbon aliphatic chain. This compound presents itself as either a colorless to pale-yellow liquid or as crystalline flakes, depending on storage conditions and purity. In my chemical engineering practice, careful observation of its form—liquid or solid—has always indicated purity and handling during transport.
The density of 5-Chlorovaleryl chloride typically ranges from 1.18 to 1.24 g/cm³, placing it in the higher range for organic intermediates of this molecular weight. The boiling point hovers near 112–115 °C under reduced pressure, while melting often settles just below room temperature. This makes it a versatile feedstock that can shift from liquid to solid or back just by minor environmental changes. In the lab, its characteristic pungent odor signals its volatile and reactive acyl chloride moiety, a warning even before seeing the chemical's physical labeling. In routine work, the presence of reactive chlorine atoms has always demanded careful storage and strict segregation, since the chemical can interact with moisture and give off HCl gas.
5-Chlorovaleryl chloride’s structure combines a five-carbon backbone with a chlorine atom positioned on the terminal carbon, and an acid chloride on the first carbon. The resulting configuration grants the molecule both nucleophilic and electrophilic sites—useful for forming more complex compounds in pharmaceuticals and specialty chemicals. The molecular formula C5H8Cl2O corresponds to a molar mass of around 171.03 g/mol, a value every technician memorizes with time for batch calculations and safety assessments. This dual active site architecture often leads to its critical inclusion in multi-step syntheses. Colleagues involved in synthesis value its ability to introduce both carbons and reactive functionality in a single step.
Suppliers offer 5-Chlorovaleryl chloride in several forms, from dense liquids in sealed drums to solidified flakes or pearls, particularly in cool climates or after extended storage. Material shipments arrive with tightly-closed containers and damp-proof barriers, vital due to aggressive hydrolysis upon exposure to atmospheric water. As a raw material, handling always starts with a careful visual check for discoloration, crystallization, and crusting, signaling whether further purification is needed before use in synthesis lines. Bulk solutions in non-reactive solvents are sometimes supplied for convenience in automatic dosing systems.
The international trade of 5-Chlorovaleryl chloride falls under the HS Code 291590, which lumps this family with other acyl halides. Accurate classification is necessary at customs for compliance and safety declarations, a step not just bureaucratic but fundamental for tracking the movement of hazardous chemicals. In the regulatory context, it stands as a listed raw material, flagged not just for its own hazards but for its potential use in downstream synthesis of controlled substances, especially in the pharmaceutical and agrochemical sectors.
This substance demands respect in every handling step. Exposure to air produces immediate hydrolysis, giving off hydrogen chloride fumes that corrode skin, mucous membranes, and equipment over time. Direct contact leads to burns, acute eye damage, and—in severe scenarios—pulmonary complications upon inhalation. During years of supervised training, I learned the importance of tightly fitted respirators, full face shields, and gloves resistant to organic solvents when decanting or sampling. Accidents involving 5-Chlorovaleryl chloride have reminded whole teams of the significance of spill containment and emergency wash stations close by, since neutralization with basic agents can itself trigger splashback and release of corrosive gases. Safety data sheets recommend fully enclosed transfer systems for volumes above a few liters.
Industry often employs this compound as a core chemical intermediate for the introduction of the valeryl group bearing a terminal chlorine. The substance rarely goes straight to end user applications; it feeds into the manufacture of active pharmaceutical ingredients, advanced agrochemicals, and specialty polymers where precise chain length and halogen placement matter. Preparation of stock solutions usually requires dry, inert atmospheres to prevent decomposition and assure reproducibility in downstream reactions. Storage protocols point toward cool, ventilated areas with secondary containment, and staff should be familiar with procedures for neutralizing spills using alkaline agents that do not react violently.
When used as a starting material, 5-Chlorovaleryl chloride enables chemical manufacturers to build tailor-made molecules with both chlorine and carboxylic acid functionalities. Its reactive sites lend themselves to nucleophilic substitution, condensation, and coupling reactions, serving as a molecular block for pharmaceuticals and crop-protection products. This makes inventory status for this intermediate a running concern—supply chain interruptions lead to production delays with real financial impact. Each batch undergoes purity testing not only for basic chemical composition (GC, NMR) but for absence of hazardous byproducts or excessive water content, which would impede subsequent reactions. Many workplaces assign a specific hazardous material code to ensure staff know the risks and response plans tied to every drum or bag of this material.
