Methyl 4-Chloroacetoacetate: A Practical Look at Its Properties, Structure, and Uses

What is Methyl 4-Chloroacetoacetate?

Methyl 4-Chloroacetoacetate brings together a set of chemical properties that make it a staple starting point in labs and industries. As an organic compound, it falls under the acetoacetate family, recognized for their roles in making pharmaceuticals, agrochemicals, and a range of fine chemicals. The molecular formula C5H7ClO3 outlines its backbone—this simple blend of carbon, hydrogen, chlorine, and oxygen produces a material that impacts a wide range of applications. Its structure features a methyl ester function and a chloro group attached at the fourth position, which usually boosts reactivity and allows for further modification in downstream processing.

Physical Properties and Appearance

In daily operations, the look and handling of Methyl 4-Chloroacetoacetate matter almost as much as what happens at the molecular level. Most batches come as a clear to pale yellow liquid. Occasionally, especially under lower temperatures or high-purity conditions, users might find it as a crystal or in solid flakes, but the liquid remains the dominant form in the market. With a density around 1.28 g/cm³, it stands heavier than water—a property I have relied on for phase separation during synthesis and extractions. Boiling occurs at about 220-225°C, and caution enters the picture as this temperature also triggers decomposition. Its solubility profile splits between organic solvents and limited water compatibility, making it straightforward to clean glassware after reactions.

Specifications and Key Details

Chemical shipments demand precise specs, and Methyl 4-Chloroacetoacetate lives up to it with a purity usually pushing 98% or more, depending on supplier. I have measured and cross-referenced the refractive index (about 1.446 at 20°C) and found it consistent—useful for confirming quality before unsealing a new drum. Storage involves keeping it cool and shielding against sunlight, as exposure accelerates hydrolysis and possible formation of byproducts. Methyl 4-Chloroacetoacetate holds the HS Code 2918300090. This number facilitates customs checks and logistic paperwork. Many use cases require bulk orders, so tracking lot numbers, container types (drums, HDPE bottles, IBCs), and shelf life protects both the investment and lab safety.

Chemical Structure and Reactivity

This compound draws attention in synthetic routes due to its reactive sites. The methylene group, activated by the adjacent carbonyls, makes nucleophilic additions and substitutions more efficient. I remember using it to introduce specific side chains in custom pharmaceutical APIs. The chlorine atom at the 4-position behaves as a good leaving group, which allows alkylation, halogen exchange, and cyclization steps during manufacturing or research runs. The ester function opens the door for hydrolysis, amidation, or transesterification—flexibility prized in both academic and industrial labs. Its crystal lattice, when formed, reveals clean, sharp-edged monoclinic geometry, but as mentioned, most users encounter the liquid.

Safe Handling and Hazards

Risks with Methyl 4-Chloroacetoacetate should never be underestimated. Exposure means skin and eye irritation, so gloves, goggles, and proper fume hoods become a daily habit, not just compliance. Vapors can build up in confined spaces, and over my time working with this material I have seen headaches and dizziness when ventilation failed. It combusts with difficulty, but underlying flammability means no open flames or high-heat sources nearby. Spills require absorbent pads and proper waste collection rather than casual cleanup, since residues can etch surfaces or trigger discomfort. Material Safety Data Sheets from reputable suppliers detail these points, and anyone working with raw materials will find this essential reading before the first bottle gets opened.

Applications and Use as a Raw Material

Methyl 4-Chloroacetoacetate's power lies in its role as a precursor. Structurally versatile, I have seen it built into high-value drugs, protective agrochemical agents, and flavor intermediates. The chemical structure offers entry points for functional group transformations, and production teams in specialty and fine chemicals routinely plan syntheses around it. Innovation in dye, pigment, and polymer work relies on the reactivity bestowed by the chloro and acetoacetate units. It’s not just building blocks—sometimes it acts as an intermediate linking one complex molecule to another, bridging raw supply with finished pharmaceuticals or crop protections. In scale-up, purity assurance, robust storage, and clean records protect business and worker safety together. Waste handling requires neutralization before disposal, since the compound’s potential to pollute storage tanks or soil can show up long after routine use fades from memory. Fact-based management practices and up-to-date environmental controls prove crucial to long-term use.