Hexamethylenetetramine, Methenamine, Hexamine, Methenamine, Hexamethylene Tetramine, Hexil Methylenamine, E239, HMT, HMTA, 100-97-0

Hexamethylenetetramine, Methenamine, Hexamine, Methenamine, Hexamethylene Tetramine, Hexil Methylenamine, E239, HMT, HMTA, 100-97-0

📖 Hexamethylenetetramine (CAS 100-97-0) – English Overview

🔹 General Description

Hexamethylenetetramine, also known as Hexamine, Methenamine, Urotropine, HMTA, E239, is a white crystalline powder with the molecular formula C₆H₁₂N₄.

• It is odorless, stable, and versatile.

• Highly soluble in water (895 g/L at 20 °C), also soluble in ethanol and chloroform, but insoluble in ether.

• It sublimates/decomposes around 280–300 °C.

• Density: ~1.33 g/cm³.

• pKa: 5.1 at 25 °C.

• Flash point: ~250 °C.

🔹 Synonyms and Identifiers

• Common names: Hexamine, Methenamine, Urotropine, Formin, Aminoform, HMTA, E239.

• Other synonyms: Urex, Hiprex, Carin, Uroqid, Cystogen, Heraxuts, Antihydral, Mandelamine, Grasselerator 102, Hexaloids, Aminoformaldehyde, Hexaform, Ammoform, Aceto-HMT, Resotropin, etc.

• Registry numbers: CAS 100-97-0, EINECS 202-905-8.

• Structure: Symmetrical adamantane-like cage with four nitrogen atoms capable of forming coordination complexes.

🔹 Production Method

Manufactured by condensation of formaldehyde and ammonia under controlled conditions:

• Formaldehyde solution reacts with excess ammonia at ~50–70 °C.

• The mixture is concentrated, crystallized, filtered, and dried.

• Final product purity: ≥99%.

🔹 Applications

• Fuel: Solid fuel tablets for camping stoves, military rations, smokeless flame.

• Organic synthesis: Intermediate for pharmaceuticals, plastics, explosives (e.g., RDX).

• Resins: Curing agent in phenolic resins (adhesives, coatings, laminates).

• Rubber: Vulcanization accelerator (Accelerator H).

• Textiles: Shrinkage inhibitor, finishing agent.

• Pharmaceuticals: Urinary tract disinfectant (acidic urine releases formaldehyde), diuretic, topical antiperspirant.

• Defense: Gas mask absorber (mixed with NaOH and sodium phenolate, absorbs phosgene).

• Corrosion inhibitor: Hydrochloric acid pickling of boilers.

• Analytical chemistry: Used for determination of metals (Bi, Mn, Co, Pt, Mg, Li, Cu, In, Th, Be, Te, etc.) and halides (Br⁻, I⁻).

🔹 Health and Safety

• Toxicity: LD₅₀ (oral, rabbit) ~9200 mg/kg.

• Hazards: Flammable solid, irritant to skin (can cause dermatitis).

• Risk codes: R11 (Highly flammable), R42/43 (May cause sensitization by inhalation/skin contact).

• Safety precautions:

  • Keep away from ignition sources (S16).

  • Avoid inhalation of dust (S22).

  • Avoid skin contact (S24).

  • Wear protective gloves (S37).

• Storage: Cool, dry, sealed, away from acids and oxidizers. Shelf life ~12 months.

• Regulation: As food additive E239, permitted only in limited quantities (e.g., certain cheeses, fish). FAO/WHO JECFA has set acceptable daily intake levels.

🔹 Key Properties Table

📊 Hexamethylenetetramine (CAS 100‑97‑0) – Suitability Table

📌 Summary

• Stabilized Grade: For long storage, resin and polymer applications.

• Unstabilized Grade: For fuel and organic synthesis.

• Pharma Grade: For pharmaceutical industry, special purity.

• High Purity: For analytical and laboratory use.