Chloroprene Storage & Tank Compatibility

Storing Chloroprene? Start Here

Storing chloroprene? Start here. Chloroprene (2-chloro-1,3-butadiene, CAS 126-99-8; formula C₄H₅Cl) is a clear, colorless, highly volatile liquid and the monomer used to make polychloroprene (neoprene) synthetic rubber. It is a chlorinated diene — an unsaturated hydrocarbon, not a water-based chemical — so it dissolves and swells common plastics, and materials of construction (MOC) matter far more here than in routine tank selection. Chloroprene is also extremely flammable (flash point well below 0°F) and a reactive monomer: it autooxidizes rapidly in air to form unstable peroxides that can trigger an exothermic, self-accelerating polymerization, so it is always handled inhibited, cold, and under an inert blanket. It is additionally classified for carcinogenicity, mutagenicity and reproductive toxicity. Choosing the wrong tank material risks permeation, swelling, monomer contamination, and loss of containment. The sections below give the honest material answer and the controls that keep chloroprene stable.

Can you store chloroprene in a poly tank?

No. A standard polyethylene (HDPE or crosslinked XLPE) or polypropylene tank is not suitable for chloroprene storage. As a chlorinated diene hydrocarbon it permeates, swells and softens the polyolefin wall — the tank loses strength, the monomer is contaminated, and vapor escapes through the wall. The monomer's very high volatility and its peroxide/polymerization reactivity make an unlined poly vessel doubly wrong for this service. Use one of the following instead:

• 304 / 316 stainless steel — the standard clean, durable choice for chloroprene service.
• Carbon steel — used for bulk chloroprene with the correct inhibitor and cold, inert handling program.
• Fluoropolymer-lined steel, or FRP built with a chemical-resistant novolac vinyl-ester resin and synthetic veil (confirm with the fabricator).

Whatever the wall material, keep the polymerization inhibitor active, exclude air and oxygen with a nitrogen pad to prevent peroxide formation, store cold to limit both volatility and self-polymerization, and monitor temperature. Provide pressure/vacuum relief and flame arrestors appropriate for a low-flash, low-boiling liquid.

Material compatibility at a glance

Store chloroprene in stainless steel (304/316), inhibited and nitrogen-blanketed carbon steel, or fluoropolymer-lined steel. Polyethylene and polypropylene tanks are not suitable — this chlorinated diene monomer permeates and swells the resin and is far too volatile and reactive for an unlined poly vessel.

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

• Highly flammable (NFPA F=3, flash point -4°F): a low-boiling Class IB liquid whose vapors form ignitable mixtures across almost all ambient conditions. Bond and ground transfers, eliminate ignition sources, and ventilate enclosed spaces.
• Peroxide and polymerization hazard (NFPA R=1): chloroprene autooxidizes rapidly in air, even near 0°C, forming unstable peroxides that catalyze an exothermic, self-accelerating polymerization. Keep it inhibited, exclude oxygen with an inert blanket, store cold, and monitor temperature.
• Carcinogen / mutagen / reproductive toxicant: classified H350/H340/H360 — use closed transfer, ventilation and respiratory protection, and minimize exposure.
• Acute toxicity by all routes: toxic if inhaled, swallowed or in skin contact (H310 fatal in contact with skin). Use chemical-resistant gloves and full PPE; avoid skin and vapor contact.
• Thermal decomposition: when heated to decomposition it emits highly toxic chlorine-containing fumes. Keep away from heat and open flame.
• Containment: provide secondary containment, spill control, and compatible (non-polyolefin) transfer hardware; the monomer is only slightly soluble in water and toxic to aquatic life.

Common questions

Why can't I use a polyethylene tank for chloroprene?

Chloroprene is a chlorinated diene hydrocarbon monomer. It permeates and swells polyethylene (HDPE and XLPE) and polypropylene, weakening the wall, contaminating the monomer, and letting vapor pass through. Combined with its very low flash point and peroxide/polymerization reactivity, polyolefin tanks are rated unsuitable for chloroprene service.

What tank material should I use for chloroprene?

304 or 316 stainless steel, inhibited carbon steel with cold inert handling, or fluoropolymer-lined steel. FRP works only when built with the correct chemical-resistant vinyl-ester resin and veil. These are custom-fabricated, blanketed, relief-protected vessels — not stock poly tanks.

Does chloroprene need an inhibitor?

Yes. Commercial chloroprene is stabilized with a polymerization inhibitor and must be kept away from air, because it autooxidizes to unstable peroxides that can set off a runaway exothermic polymerization. Store it inhibited, cold, and under an inert nitrogen blanket.

Is chloroprene flammable?

Extremely. With a flash point of about -4°F and a boiling point near 139°F it is a low-boiling Class IB flammable liquid (NFPA flammability 3). Control ignition sources, bond and ground during transfer, use flame arrestors, and ventilate vapor spaces.