Dichloroacetic Acid Storage & Tank Compatibility

Storing Dichloroacetic Acid? Start Here

Dichloroacetic acid (C₂H₂Cl₂O₂, CAS 79-43-6) is a strong, corrosive carboxylic acid used in chemical synthesis, pharmaceutical intermediates, and specialty acidification. It is a colorless, hygroscopic liquid or low-melting solid that is freely miscible with water and considerably stronger than acetic acid, driving an aqueous pH near 1.2. Because it carries serious health hazards - severe burns, organ toxicity, and suspected carcinogenicity - it demands closed, well-vented storage with full personal protection. For tank selection the key facts are that it corrodes common metals yet is handled well by polyethylene at ambient temperature. High-density polyethylene (HDPE) and crosslinked polyethylene (XLPE) vessels, paired with chemically matched gaskets and fittings, give a sound, cost-effective containment path when the acid is kept cool and concentrations are verified.

Is HDPE / XLPE Compatible with Dichloroacetic Acid?

Yes - at ambient temperature. Polyethylene resistance charts rate HDPE as resistant to dichloroacetic acid at 20 C, the same favorable rating given to acetic acid and chloroacetic acid. As a carboxylic acid with no oxidizing, hydrocarbon, or solvent character, dichloroacetic acid does not swell or dissolve polyethylene, so HDPE and crosslinked polyethylene (XLPE) are appropriate tank materials. The honest caveat is temperature: the same charts show resistance narrowing to a conditional rating near 60 C, so storage should stay cool (below about 30 C, which also limits the acid's hygroscopic uptake) and away from direct heat. Specify a gasket, valve, and fitting package matched to the concentration in use, and confirm elastomer grades (EPDM or fluoroelastomer) with the supplier rather than assuming a single seal fits every dilution.

Material compatibility at a glance

Dichloroacetic acid is a strong, corrosive carboxylic acid that is aggressive to metals but well handled by polyethylene at ambient temperature. HDPE and crosslinked polyethylene (XLPE) are the practical tank materials, matching the resistance shown for acetic and chloroacetic acids on polyethylene charts. Avoid carbon steel and stainless steel, which the acid corrodes. Keep storage cool (below 30 C) because resistance margins narrow as temperature rises, and confirm all gasket, valve, and fitting grades against concentration before service.

Ratings: S suitable · C conditional / limited · U unsuitable. Verify against the cited resistance charts and your concentration/temperature before specifying.

The safety that actually matters

• Causes severe skin burns and eye damage (H314/H318) and is toxic in skin contact (H311) - wear acid-resistant gloves, face shield, goggles, and chemical apron.
• Suspected carcinogen and reproductive hazard (H350/H360) and damages organs (H370/H372) - minimize all exposure and handle in well-ventilated or enclosed systems.
• Corrosive to metals (H290) - use polyethylene tanks and non-metallic fittings; isolate from carbon and stainless steel.
• Very toxic to aquatic life (H400/H411) - bund and contain to prevent any release to drains or waterways.
• Keep cool and tightly sealed (hygroscopic) and away from strong oxidizers, bases, and reducing agents.
• Provide eyewash and safety shower at the point of use and follow the current Safety Data Sheet.

Common questions

Can I store dichloroacetic acid in a polyethylene tank?

Yes. HDPE and XLPE are rated resistant to dichloroacetic acid at ambient temperature, the same as for acetic and chloroacetic acids. Keep the tank cool (below about 30 C), tightly sealed against moisture, and match the gaskets and fittings to your concentration.

Why not use a stainless steel tank?

Dichloroacetic acid is a strong acid that is corrosive to metals (H290). It attacks both carbon steel and stainless steel, so non-metallic containment such as polyethylene is the recommended choice.

How strong an acid is dichloroacetic acid?

It is far stronger than acetic acid, with an aqueous pH near 1.2 at 129 g/L. That acidity is what makes it corrosive to metals and skin, while polyethylene remains unaffected at ambient temperature.

Does temperature affect tank compatibility?

Yes. Polyethylene resistance is strong at 20 C but narrows to a conditional rating near 60 C. Keep storage cool and avoid heated service to maintain the safety margin, and verify any warm-process use with the tank maker.