Protocatechualdehyde stands out as an important aromatic aldehyde with the molecular formula C7H6O3 and a molecular weight of 138.12 g/mol. The full chemical name, 3,4-dihydroxybenzaldehyde, maps directly to its core structure: a benzene ring with two hydroxyl groups positioned at the 3 and 4 carbon sites, plus an aldehyde group at the 1 position. That pattern of substitution gives this compound a unique set of physical and chemical behaviors. A person handling it will usually see off-white or light brown solid, which takes various shapes including crystalline flakes, powder, and sometimes small pearls. With a melting point typically around 143–146°C, this aromatic aldehyde dissolves easily in water, ethanol, and ether—making it versatile for lab and industrial use.
A look at the structure shows how the hydroxy groups next to the aldehyde enhance its reactivity. Among aromatic aldehydes, protocatechualdehyde shows higher polarity because those hydroxyls push electrons toward the ring, increasing its solubility and broadening its reactivity compared to simple benzaldehydes. Its solid form is often used because it's stable under ordinary storage and transport conditions. A close-up of the crystalline powder reveals a typical density near 1.33 g/cm³. For researchers or chemical handlers, this means storage does not call for unusual requirements provided containers remain sealed and dry. Density and form help determine how people measure and blend the compound—whether working at a laboratory bench or running larger synthesis operations.
Quality grades and specifications matter, especially for raw materials destined for pharmaceuticals, dyes, and food processing applications. Common sourced grades require purity above 98%, limited moisture, and negligible heavy metal contamination. The international commodity code, or HS Code, for this aromatic aldehyde usually groups with other organic acids and their derivatives. Under the Harmonized System, one often cites codes like 2913000090 for aldehydes with unrelated functions, and classification can vary slightly by country. As a synthetic intermediate, protocatechualdehyde often comes from oxidation of vanillin or by demethylation of related compounds. Large-scale producers rely on chemical feedstocks, including guaiacol or eugenol, reflecting a demand for cost control and reliable supply chains.
Though it sounds technical, the real-world forms of the compound—flakes, powders, or pearls—help companies choose the best product for their process. Labs favor powder for quick dissolving or making solutions up to gram-scale. Factories sometimes prefer crystalline flakes or packed pearls for ease of metering and reduced risk of airborne dust. The compound sometimes appears as a low-viscosity liquid in special preparations, like concentrated solutions for direct dosing. Temperature stability and non-volatility mean that for most handlers, basic laboratory safety like gloves and goggles provide enough protection during normal operations. Facilities that transfer bulk containers use dust collection and sealed transfer systems to cut inhalation risk and keep the workplace clean.
People in the field learn quickly: no matter how useful a chemical seems, safety sits up front. Protocatechualdehyde carries health hazards similar to other phenolic aldehydes—skin and eye irritation, risk of inhalation injury, and some concerns over longer-term exposure. Its aldehyde functionality reacts with amines and nucleophiles, which supports its use in synthesis but also means gloves matter. Spilled powder can cause irritation, so responsible handlers use closed transfer or fume hoods during weighing and blending. Regulatory agencies such as OSHA and ECHA include the raw material in workplace inventories, flagging it as harmful but not acutely toxic. Standard protocols require safe disposal with other hazardous organics, and storage should avoid high heat or open flames, despite the compound's modest flammability. The Safety Data Sheet (SDS) warns, too: washes after contact and prompt cleanup matter to prevent reaction with other lab chemicals.
What pulls protocatechualdehyde into focus isn’t only its chemical quirks but the way real industries rely on its unique structure. It appears everywhere from pharmaceutical manufacturing—where it acts as a synthetic block for cardiovascular and anti-inflammatory drugs—to dye chemistry and food processing, where natural phenolics command high value. The position of the hydroxy and aldehyde groups turns this compound into a flexible building block for more complex molecules. Companies seeking data-supported manufacturing turn to high-purity grades, offering certificates of analysis covering appearance, density, purity, and heavy metal content. Plant operators lean on suppliers with consistent specifications, since contamination or deviation in physical form can wreck whole batches.
Spectroscopists enjoy a straightforward NMR and IR profile with clear peaks from aldehyde and hydroxyl protons. Quality control labs rely on HPLC, GC-MS, and melting point analysis to confirm each batch. Chemists check density, appearance, solubility, and crystal habit. A modern certificate outlines everything from precise formula weight to detailed handling protocols, reflecting the increasing regulatory focus. Regulatory authorities like REACH and local environmental bureaus expect not just safe transport but full disclosure of hazardous qualities—fire, toxicity, and persistent environmental impact. The formula C7H6O3 shows up on container labels, along with risk and safety phrases, so anyone opening a drum knows what sits inside.
Manufacturers improve safe handling by automating powder transfers, installing better ventilation, and investing in safer packaging—reducing spills and exposure. Substitution sometimes means using lower-toxicity aldehydes, though for specialized synthesis, few chemicals compete with protocatechualdehyde’s reactivity. Waste solutions or spilled powder get directed into hazardous waste streams, and conscientious firms track cradle-to-grave environmental fate by monitoring air and water emissions. Testing and treating waste streams for aldehyde load help prevent local pollution. In future, biotechnological routes from renewables such as lignin-derived feedstocks could support both safety and environmental goals, making the supply chain more sustainable while keeping quality high.
