Chloranthraquinone O-Ring Compatibility: Which Compounds Hold Up

Chloranthraquinone (chloroanthraquinone family) is a chlorinated anthraquinone intermediate used in vat and disperse dye manufacture and specialty organic synthesis. Seals on reactor nozzles, transfer valves, pump flanges, sample ports, and solvent or melt transfer lines see a halogenated aromatic ketone that punishes everyday polar elastomers. Pick poorly and you get swell, softening, and early weep.

This guide maps the handbook Chemical Compatibility Chart row for chloranthraquinone to practical compound choices.

Where it shows up

• Vat and anthraquinone dye manufacture: 1- and 2-chloroanthraquinone building blocks for textile and specialty colorants
• Disperse and intermediate dye chemistry: aminoanthraquinone and related dye precursors
• Specialty organic synthesis: photo-reagents and further functionalization of the anthraquinone nucleus
• Reactor, melt, and solvent transfer: flanges, valves, and pump skids moving neat solid melts, slurries, or solvent-cut streams
• Drum and tote handling: fill heads and sample connections on intermediate packaging

Service is usually neat melt, slurry, or solvent-cut chlorinated anthraquinone in steel or stainless equipment near ambient to moderately warm process temperatures. Chart ratings assume a generic commercial compound near room temperature. Concentration, heat, and co-solvents change outcomes.

How chloranthraquinone stresses an O-Ring

Chlorinated anthraquinones are halogenated aromatic organics. That chemistry is hard on EPDM, neoprene, and butyl stocks that shine in polar or aqueous duty, and it favors fluorocarbons (FKM and FFKM) and PTFE. Nitrile and HNBR can work for many static covers on this chart row, but they are not the preferred start when immersion is continuous. Heat and solvent carriers accelerate damage even when a short splash test looked acceptable. See Chemical Compatibility and Failure Analysis.

Handbook chart ratings for chloranthraquinone

Same rating badges and layout as the interactive chart. Search chloranthraquinone on the Chemical Compatibility Chart to pin the live row.

Best family on the chart row: Viton® / FKM (V). FFKM and PTFE also rate excellent (1). Nitrile, HNBR, and fluorosilicone rate good (2). Polyurethane rates poor (3). EPDM, neoprene, and butyl are not recommended (4). Silicone and Aflas® lack data (X) on the handbook matrix.

Recommended O-Ring materials

First choice: Viton® / FKM

FKM (Viton®) is rated excellent (1) and is the chart’s preferred letter for chloranthraquinone. It is the everyday fluorocarbon start for dye-intermediate transfer and static cover seals when temperature and pressure stay inside commercial FKM windows. Use 70 Shore A for most static flanges; step hardness or add a back-up ring when pressure and clearance gap climb.

Also usually serviceable

• FFKM 1Excellent Use for mixed aggressive synthesis streams, higher heat, or when plant standards call for perfluoroelastomer.
• PTFE 1Excellent Chemically inert but rigid. Consider PTFE-encapsulated when you need rebound.
• Nitrile (Buna-N) 2Good Often workable for static duty; confirm grade immersion data for continuous chloranthraquinone contact.
• HNBR 2Good Similar to nitrile on this row with better heat and abrasion margin in many grades.
• Fluorosilicone (FVMQ) 2Good Useful when cold flexibility matters; prefer FKM for continuous warm immersion.

Materials to use with caution or avoid

• Polyurethane 3Poor Not a first pick for continuous chloranthraquinone immersion; prefer FKM.
• EPDM 4Not recommended Wrong chemistry for halogenated aromatics; keep EPDM for polar / aqueous service.
• Neoprene (CR) 4Not recommended Avoid in continuous chloranthraquinone duty.
• Butyl (IIR) 4Not recommended Built for polar fluids and gas barrier duty, not chlorinated anthraquinone intermediates.
• Silicone (VMQ) XNo data Insufficient chart data. Do not assume general-purpose silicone fits dye-intermediate duty.
• Aflas® (FEPM) XNo data Insufficient chart data. Do not assume steam or amine grades are automatic fits here.

Physical properties to match (after chemistry)

A chart 1 means the polymer family usually survives the fluid. Finish the spec with the gland and process needs:

• Hardness: 70 Shore A for most static covers and flanges; 90 Shore A or a back-up ring when pressure and gap climb (Shore A Hardness).
• Temperature: handbook chemical ratings are near room temperature. Warm melts, solvent recovery, and heat-traced lines age seals faster. Confirm continuous temperature against the Temperature Guide.
• Static vs dynamic: face and cover seals are mostly static; shafts and rods need abrasion and extrusion control beyond a chemical letter (groove design).
• Size: lock ID × CS (or the AS568 dash) on the Master O-Ring Size Chart before arguing compound.

Practical selection checklist

1. Confirm neat chloranthraquinone vs melt, slurry, or solvent cut and any co-solvents on the SDS.
2. Note temperature and whether the seal sees solid handling, liquid, vapor, or both.
3. Start with FKM at 70 Shore A for general static duty unless a plant standard already calls for FFKM or PTFE-encapsulated.
4. Avoid EPDM, neoprene, and butyl for continuous chloranthraquinone contact on this chart row. Treat silicone and Aflas as unproven until you test.
5. Pin Chloranthraquinone on the Chemical Compatibility Chart. For critical service, contact The O-Ring Store with fluid grade, temperature, hardness, and duty cycle.

Quick answers

Which O-Ring for chloranthraquinone?
Start with FKM (Viton®) at 70 Shore A for general static duty. FFKM and PTFE also rate excellent. Nitrile, HNBR, and fluorosilicone are usually good for static service. Avoid EPDM, neoprene, and butyl for continuous contact. Treat silicone and Aflas as unproven here until you test.

Is chloranthraquinone the same as anthraquinone on the chart?
Related anthraquinone intermediates show up in the same dye plants. Always match the exact fluid name on the chart and on the SDS.

Chart ratings are guidance for generic commercial compounds near room temperature. Concentration, temperature, and co-fluids change outcomes. Evaluate specific parts before use in critical applications.