N,N-Dimethylcyclohexylamine (DMCHA) Storage — Tertiary Amine Catalyst Tank
N,N-Dimethylcyclohexylamine (DMCHA) Storage — Tertiary Amine Catalyst Tank Selection for Polyurethane Foam, Boiler Treatment, and Specialty Chemistry
N,N-Dimethylcyclohexylamine (C6H11-N(CH3)2, CAS 98-94-2), commonly abbreviated DMCHA or commercially branded as JEFFCAT DMCHA (Huntsman), Polycat 8 (Air Products / Evonik), or Dabco DMCHA, is a colorless-to-pale-yellow tertiary amine liquid (specific gravity 0.85, boiling point 162°C, sparingly water-soluble) used primarily as a delayed-action gel catalyst in polyurethane foam manufacture (rigid spray foam, flexible-slab molded foam, integral skin foam), as a volatile corrosion inhibitor (VCI) in boiler-condensate-return systems, and as a hydrogen-sulfide scavenger in oilfield production-fluid treatment. The chemistry has a strong fishy amine odor detectable at parts-per-billion levels, making fugitive emission management an important specification driver. Bulk storage at industrial users runs from drum-and-tote scale at smaller polyurethane formulators to 5,000-25,000 gallon tanks at major polyurethane and oilfield-chemistry producers.
The six sections below cite Cole-Parmer chemical compatibility chart, Plastics International Chemical Resistance Chart, Compass Publications Chemical Resistance Handbook, Parker O-Ring Handbook ORD-5712 amine-elastomer compatibility tables, supplier safety data sheets from Huntsman JEFFCAT, Air Products / Evonik Polycat, and Dabco product lines, ACGIH TLV-TWA 5 ppm 8-hour TWA, NIOSH RTECS HY8525000, and DOT 49 CFR 173 packaging for UN 2264 N,N-Dimethylcyclohexylamine, Class 8 (corrosive) and Class 3 (flammable liquid) subsidiary, Packing Group II shipments.
1. Material Compatibility Matrix
DMCHA is a tertiary amine compatible with standard polyethylene tank construction across the full purity range. The chemistry attacks copper alloys (forms cuprammonium-type complex), aluminum (forms aluminate at elevated temperature), and zinc (forms zincate); ferrous metals are passivated by amine adsorption. Elastomer compatibility favors EPDM over Viton; nitrile is acceptable at dilute concentrations only.
| Material | Pure DMCHA | Aqueous dilute | Notes |
|---|---|---|---|
| HDPE / XLPE | A | A | Standard for storage tanks; no permeation issue |
| Polypropylene | A | A | Standard for fittings, pump bodies |
| PVC | B | A | Acceptable to 50°C; verify temperature |
| CPVC | A | A | Standard for piping at elevated temperature |
| PVDF (Kynar) | A | A | Premium for high-temperature service |
| PTFE / FEP / PFA | A | A | Premium for high-purity service |
| Carbon steel | A | A | Acceptable; amine passivation reduces corrosion |
| 304 / 316 stainless | A | A | Standard for bulk industrial service |
| Aluminum | C | C | Aluminate corrosion at elevated temperature; avoid |
| Copper / brass | NR | NR | Cuprammonium complex; never in service |
| Zinc / galvanized | NR | NR | Zincate corrosion; never in service |
| Viton (FKM) | NR | C | Severe degradation per Parker; never in service |
| EPDM | A | A | Standard elastomer for amine service |
| Buna-N (Nitrile) | C | B | Avoid concentrate; acceptable dilute |
| Natural rubber | C | B | Slow attack; avoid concentrate |
| Neoprene | B | A | Acceptable dilute; avoid concentrate |
For the dominant industrial use case (bulk storage at polyurethane formulators), HDPE rotomolded tanks with PP fittings and EPDM gaskets are the OneSource Plastics standard recommendation. The strong amine odor and ACGIH 5 ppm TLV drive specification of vapor-tight tank vents with carbon-bed odor-control polish on the vent discharge.
2. Real-World Industrial Use Cases
Polyurethane Foam Catalyst (Dominant Industrial Use). Rigid spray polyurethane foam (SPF) for building insulation uses 0.5-2.0 parts DMCHA per 100 parts polyol (pphp) as a delayed-action gel catalyst that balances cream time, gel time, and tack-free time during the on-site spray application. Flexible-slab and molded-foam furniture cushion manufacture uses 0.05-0.5 pphp DMCHA as part of a multi-amine catalyst package. Integral-skin foam (steering wheels, armrests) uses similar dosage. SPF formulators (BASF Elastospray, Huntsman Tigerfoam, Dow EconoSpray, Honeywell Solstice GBA) maintain 5,000-25,000 gallon DMCHA bulk inventory for blending into polyol resin master batches; formulator-to-applicator distribution is in pre-blended A-side and B-side drums or totes.
Boiler Condensate Volatile Corrosion Inhibitor. Industrial steam systems use neutralizing-amine treatment to control condensate-return-line corrosion from carbonic acid (from CO2 dissolved in condensate). DMCHA is one of several alkalinity-amines (alongside cyclohexylamine, morpholine, diethylaminoethanol) used at 1-10 ppm dosage in steam to maintain condensate-return pH 8.5-9.5. Treatment-program suppliers (Nalco Water, ChemTreat, Veolia Hydrex, Solenis) blend proprietary multi-amine boiler treatment products containing DMCHA. End-user industrial sites store treatment product as blended solution rather than raw DMCHA.
Oilfield Hydrogen Sulfide Scavenger. Sour-crude and sour-gas production fluid streams use amine-based H2S scavengers including triazine chemistry and tertiary-amine blends. DMCHA appears in proprietary blended scavenger products at oilfield-chemistry suppliers (Schlumberger M-I, Nalco Champion, Baker Hughes). Field-use containers are 55-gallon drum and 330-gallon IBC tote scale.
Specialty Synthesis Catalyst. Tertiary-amine organic-synthesis catalysis applications (epoxy curing, polyurethane elastomer cure, acrylate polymerization) use DMCHA as a base catalyst at 0.1-2% dosage. End-user volumes are small (drum-scale).
Carbon Capture Pilot Programs. Tertiary-amine blended absorbents for CO2 capture from flue gas and process gas streams include DMCHA in proprietary formulations; commercial-scale carbon-capture deployment in 2026 remains limited to pilot demonstration units.
3. Regulatory Hazard Communication
OSHA. 29 CFR 1910.1000 Table Z-1 has no PEL specifically listed for DMCHA; OSHA general-duty clause and PPE standard 29 CFR 1910.132 apply. ACGIH TLV-TWA 5 ppm 8-hour TWA is the typical industrial-hygiene compliance reference; the chemistry has a strong fishy amine odor with detection threshold at 0.01-0.1 ppm, making odor complaints often the first compliance signal at fugitive-emission exposure scenarios.
NFPA 704 Diamond. NFPA Health 3, Flammability 2, Instability 0, no special hazard. Flash point 41°C closed-cup puts DMCHA in the Class IC flammable-liquid (NFPA 30) category; bulk storage requires flammable-liquid storage controls including bonding/grounding for transfer operations.
DOT Hazmat. Bulk DMCHA ships under UN 2264, N,N-Dimethylcyclohexylamine, Class 8 (corrosive) primary, Class 3 (flammable liquid) subsidiary, Packing Group II. Drum and IBC packaging per DOT 49 CFR 173 with both corrosive and flammable-liquid placard requirements.
EPA TSCA Inventory. DMCHA is on the EPA TSCA inventory; no SNUR or restriction. Not a HAP under Clean Air Act. SARA Title III TRI not federally listed; state right-to-know reporting requirements vary (NJ workplace hazardous substance list).
EU REACH. Registered substance with harmonized hazard classification: H226 (flammable liquid), H302 (harmful if swallowed), H311 (toxic in contact with skin), H314 (causes severe skin burns), H331 (toxic if inhaled). EU classification drives PPE specification at multinational producer sites that supply to both US and EU markets.
Spray Polyurethane Foam Application Standards. SPRAY POLYURETHANE FOAM ALLIANCE (SPFA) workplace exposure-control guidance for SPF installer crews includes DMCHA and other amine catalyst exposure-monitoring recommendations during high-pressure spray application. State-licensed SPF applicator programs in CA, NY, and TX include amine-catalyst exposure training in the licensure curriculum.
4. Storage System Specification
Bulk Tank Construction. Industrial DMCHA bulk storage at polyurethane formulators uses HDPE rotomolded tanks in 1,500-10,000 gallon range from Norwesco, Snyder, Chem-Tainer, Enduraplas, and Bushman; larger installations at major SPF and slabstock producers use 316 stainless steel tanks 10,000-25,000 gallons. Tank vents must be vapor-tight and routed to a carbon-bed odor-control polish on combined tank-farm vent header to manage fugitive amine odor in plant air and at the property line. Nitrogen blanket on tank vapor space preferred for high-purity SPF formulator service.
Day-Tank for Continuous Dosing. Polyurethane resin-blending operations use day-tanks (200-1,000 gallons) decoupled from the bulk-storage tank for steady metering pump suction during batch resin blending. Standard HDPE construction with low-level alarm and auto-fill from bulk tank.
Pump Selection. Diaphragm metering pumps with EPDM diaphragms and PVC heads are standard for additive-dosing into polyurethane resin master batches. Magnetic-drive centrifugal pumps for bulk transfer service to eliminate mechanical-seal leak and amine-odor fugitive-loss risk. Air-operated diaphragm pumps acceptable for batch-transfer applications.
Secondary Containment. 40 CFR 264.175 federal RCRA standard requires containment sized to the larger of 10% of total tank capacity OR 100% of largest tank capacity. State rules (CA, NY, NJ) commonly require 110% as state best-practice. Containment material: concrete with chemical-resistant coating or HDPE liner; steel acceptable with epoxy-phenolic lining.
Flammable-Liquid Storage Controls per NFPA 30. DMCHA is a Class IC flammable liquid. Tank-farm requirements: bonding and grounding for all transfer operations, flame-arrestor on tank vent (where vapor-recovery condenser is not used), separation distance from process buildings and property lines per NFPA 30 Chapter 22 outside above-ground tank standard, and explosion-relief venting on enclosed indoor storage.
Drum and Tote Storage. 55-gallon DOT 1A1 closed-head steel drums and 330-gallon IBC totes are standard small-volume DMCHA containers. Drum and tote storage in dedicated secondary-containment pallets per 40 CFR 264.175 with bonding-and-grounding cables for all dispensing operations.
5. Field Handling Reality
Odor Detection vs Toxicity Threshold. DMCHA has fishy amine odor detectable at 0.01-0.1 ppm; ACGIH TLV-TWA is 5 ppm. The ratio means that operators detect strong odor at concentrations 50-500x below the toxicity-protective TLV. Odor complaints at the property line or in plant offices are routine at SPF formulator and oilfield-chemistry producer sites; fugitive-emission management with carbon-bed adsorber polish on tank-farm and resin-blending area exhaust ventilation is the standard control. Olfactory fatigue (operators stop noticing the odor after extended exposure) is a known industrial-hygiene blind spot; air sampling rather than odor reports must drive exposure-monitoring programs.
Skin Contact Severity. DMCHA causes severe chemical burns on direct skin contact and is moderately well-absorbed through skin. PPE protocol matches concentrated-amine handling: butyl rubber or laminate gloves, chemical-splash goggles + face shield, chemical-resistant apron over long-sleeve coveralls. ANSI Z358.1 plumbed emergency eyewash + safety shower within 10 seconds travel of any direct-handling station.
Pump Selection Detail. For SPF formulator master-batch blending, diaphragm metering pumps with EPDM diaphragms and PVC heads from LMI, Pulsafeeder, or Grundfos are the standard 2026 selection. Stainless wetted parts on bulk-transfer centrifugal pumps; magnetic-drive design preferred for fugitive-odor management.
Valve Materials. Ball valves with EPDM seats and stainless ball construction. PVC or CPVC ball valves with EPDM seats acceptable for ambient-temperature dilute service. Avoid Viton-seated valves (severe degradation).
Gasket Selection. EPDM gaskets are the standard DMCHA-service flange seal across the full concentration envelope per Parker compatibility data. PTFE envelope gaskets for premium high-temperature service. NEVER use Viton, nitrile, or natural rubber gaskets.
PPE. 29 CFR 1910.132 hazard assessment required. Standard PPE: butyl or laminate gloves, chemical-splash goggles + face shield, chemical-resistant apron over long-sleeve coveralls, NIOSH air-purifying respirator with organic-vapor cartridge above ACGIH TLV. ANSI Z358.1 plumbed emergency eyewash + safety shower within 10 seconds travel of any handling.
Spill Response per 40 CFR 264.31. Spilled DMCHA evaporates moderately (boiling point 162°C, vapor pressure 1 mm Hg at 20°C) generating strong-odor amine vapor. Response: evacuate downwind area, eliminate ignition (Class IC flammable), contain pool with absorbent (vermiculite or sand), neutralize residue with weak-acid wash (5-10% citric or acetic acid solution) to convert DMCHA to ammonium-salt form and reduce vapor odor, shovel into DOT-rated drums for off-site disposal as flammable-liquid hazardous waste. Vapor cleanup with portable carbon-bed adsorber over the spill area accelerates property-line odor recovery.
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