Trichloroisocyanuric Acid (87-90-1) Physical and Chemical Properties
Trichloroisocyanuric Acid
Chlorinated triazine oxidizer supplying a concentrated, stable source of available chlorine for disinfection, bleaching and industrial water treatment formulations.
| CAS Number | 87-90-1 |
| Family | Triazines |
| Typical Form | Powder or crystalline solid |
| Common Grades | BP, EP, USP |
Trichloroisocyanuric acid (TCCA) is an N‑chloro derivative of isocyanuric acid belonging to the s‑triazine (triazinane) trione structural class. The molecular core is an s‑triazine‑2,4,6(1H,3H,5H)‑trione (isocyanuric acid) in which the three ring nitrogen atoms are chlorinated, giving the systematic name 1,3,5‑trichloro‑1,3,5‑triazinane‑2,4,6‑trione. The N–Cl functionalities impart oxidizing and halogenating character; the triazine trione scaffold is relatively rigid (zero rotatable bonds) and polarized by carbonyl and N–Cl groups, resulting in limited lipophilicity and significant hydrogen‑bond acceptor capacity.
Chemically, TCCA is an oxidizing, halogen‑donor solid that hydrolyzes in water to release available chlorine (primarily as hypochlorous acid) while ultimately yielding cyanuric acid as a degradation product. Aqueous solutions are acidic (\(\mathrm{pH}\) in the range reported below) and the material is slightly hygroscopic. The balance of oxidative/chlorinating reactivity and moderate solid‑state stability makes TCCA widely used as a dry chlorinating and disinfecting agent; however, its oxidizer character, reactivity with organics/ammonia, and potential to generate chlorine and nitrogen trichloride on improper contact with water or incompatible materials require strict control measures in handling, storage and formulation.
Common commercial grades reported for this substance include: BP, EP, USP.
Basic Physical Properties
Density
Measured and reported density values for the solid vary with form and reporting convention. Reported entries include: - "greater than 1 at 68 °F (est)" — presented here as greater than \(1\) at \(68\,^\circ\mathrm{F}\). - "Greater than 1 at 20 °C (solid)" — presented here as greater than \(1\) at \(20\,^\circ\mathrm{C}\). - A specific measured value: \(2.07\,\mathrm{g}\,\mathrm{cm}^{-3}\).
These entries indicate a crystalline solid with bulk and particle‑dependent apparent densities (bulk powder vs. compact crystal). Bulk handling parameters (loose bulk and granular bulk) are substantially lower than crystal density and are reported elsewhere in the experimental properties.
Melting Point
Melting/decomposition behavior is dominated by thermal decomposition rather than a simple fusion event. Reported data: - Melting point: \(246.7\,^\circ\mathrm{C}\) (decomposes). - Decomposes at \(>225\,^\circ\mathrm{C}\).
The presence of N–Cl bonds and oxidative functionality causes decomposition to precede melting in many samples; thermal stability is therefore limited and heating can generate toxic/oxidizing decomposition gases.
Boiling Point
No experimentally established value for this property is available in the current data context.
Vapor Pressure
The vapor pressure is extremely low, consistent with a nonvolatile particulate solid. Reported value: - Vapor pressure = \(0.00000012\,\mathrm{mmHg}\).
Other qualitative entries list the vapor pressure as "negligible". The low vapor pressure implies atmospheric transport will be dominated by particulate deposition rather than gas‑phase volatilization.
Flash Point
Reported experimental flash behavior: - Flash point: \(>250\,^\circ\mathrm{C}\) (\(482\,^\circ\mathrm{F}\)), open cup.
TCCA is not flammable itself but is a strong oxidizer and can promote combustion of other materials; therefore flash point is not the primary hazard descriptor.
Chemical Properties
Solubility and Phase Behavior
Multiple solubility and aqueous behavior items are reported: - "Soluble in chlorinated and highly polar solvents." - "Solubility in water at \(25\,^\circ\mathrm{C}\) = \(1\,\mathrm{g}\,/\,100\,\mathrm{g}\)." (also reported as g/100 mL at \(25\,^\circ\mathrm{C}\): 1.2) - "Solubility in acetone at \(30\,^\circ\mathrm{C}\) = \(35.0\,\mathrm{g}\,/\,100\,\mathrm{g}\)." - "Water solubility = 1.2% = 1.20X10+4 mg/L at \(25\,^\circ\mathrm{C}\)." - "Solubility in water, g/100ml at \(25\,^\circ\mathrm{C}\): 1.2."
On contact with water TCCA releases hypochlorous acid (available chlorine), and concentrated or slow hydrolysis can evolve chlorine gas or chlorinating intermediates. A 1% aqueous solution is acidic (reported \(\mathrm{pH}\) range given below) because hydrolysis produces acidic chlorinated species. The limited water solubility and particulate form enable formulation as dry tablets and granules that dissolve to provide active chlorine.
Reported solution acidity: - \(\mathrm{pH} = 4.4\) (unspecified concentration). - \(\mathrm{pH}\) (1% aqueous solution) = 2.7–3.3.
These acidic, chlorine‑releasing solutions account for the compound's disinfectant efficacy and its potential to corrode sensitive alloys or damage biological tissues.
Reactivity and Stability
TCCA is a thermally unstable, strong oxidizer with specific reactive hazards: - Thermally unstable; decomposition reported at \(\sim225\,^\circ\mathrm{C}\) to \(246.7\,^\circ\mathrm{C}\) (decomposition). - Reacts violently with reducing agents, combustible organic materials, ammonium salts and many common contaminants; contact with incompatible materials can cause fire, rapid gas evolution, or explosion. - Reacts with water to release hypochlorous acid and, under certain conditions (small amounts of water, acidic concentrated mixtures or reaction with ammonia/amines), can generate nitrogen trichloride — a highly unstable and explosive species — and chlorine gas. Explicit warnings note explosive behavior when mixed with calcium hypochlorite and water. - Emits toxic chlorine and nitrogen oxides on decomposition; fire may produce chlorine and nitrogen trichloride.
Storage in the dry state and segregation from incompatible materials (amines, organic matter, reducing agents, hypochlorites and strong bases/acids under uncontrolled conditions) are central to hazard control. Some formulations (blends with cyanuric acid or salts) are used to moderate solubility and stability in commercial products.
Thermodynamic Data
Standard Enthalpies and Heat Capacity
No experimentally established value for this property is available in the current data context.
Molecular Parameters
Molecular Weight and Formula
- Molecular formula: C3Cl3N3O3
- Molecular weight: 232.41
- Exact/monoisotopic mass: 230.900524
These values reflect the triazine trione core with three chlorine substituents.
LogP and Polarity
Computed and experimental lipophilicity and polarity descriptors: - XLogP (computed): 1.2 - Reported LogP (experimental/computed entry): 0.26 - Topological polar surface area (TPSA): 60.9 - Hydrogen bond donors: 0 - Hydrogen bond acceptors: 3 - Rotatable bond count: 0
The modest log P values and appreciable TPSA indicate a relatively polar but not highly water‑soluble molecule in the solid state; available chlorine and hydrolytic behavior dominate aqueous reactivity rather than simple partitioning.
Structural Features
The core is an s‑triazine ring bearing three carbonyl (trione) functionalities; each ring nitrogen is substituted by a chlorine atom (N–Cl). Key structural consequences: - N–Cl bonds are the principal reactive sites for chlorination/oxidation and are responsible for the "available chlorine" supplied on hydrolysis. - The triazine trione core enforces planarity/rigidity and precludes rotamer flexibility (rotatable bonds = 0). - Carbonyl oxygens and ring nitrogens give three hydrogen‑bond acceptor sites (HBondAcceptorCount = 3) but no donors. - The electron withdrawing nature of the carbonyl and halogen substituents stabilizes the solid but also increases oxidizing potential toward reductants and organics.
SMILES and InChI strings for unambiguous structural representation are provided under identifiers below.
Identifiers and Synonyms
Registry Numbers and Codes
- CAS Number: 87-90-1
- EC Number: 201-782-8
- UN Number (shipping): UN2468
- UNII: RL3HK1I66B
- InChIKey: YRIZYWQGELRKNT-UHFFFAOYSA-N
- SMILES: C1(=O)N(C(=O)N(C(=O)N1Cl)Cl)Cl
- IUPAC / systematic name provided: 1,3,5‑trichloro‑1,3,5‑triazinane‑2,4,6‑trione
Additional registry identifiers and secondary codes appear in regulatory and inventory contexts; the CAS and key structural identifiers above are shown where available.
Synonyms and Structural Names
Common synonyms and tradename strings (selected from supplied synonym lists) include: - Trichloroisocyanuric acid - Trichloro‑s‑triazinetrione - 1,3,5‑Trichloro‑1,3,5‑triazinane‑2,4,6‑trione - Symclosene - TCCA - Trichlorocyanuric acid - Trichloroisocyanurate (variant) These synonyms reflect common commercial and chemical naming conventions used in industrial, pesticide and disinfectant contexts.
Industrial and Commercial Applications
Representative Uses and Industry Sectors
TCCA is a widely used chlorinating biocide and oxidizing agent in multiple sectors: - Primary use as a swimming‑pool sanitizer and algicide. - Active ingredient in dry bleaches, scouring powders, dishwashing compounds and industrial deodorants. - Employed as a disinfectant, chlorinating agent, and component in household and commercial sanitizing formulations. - Used in textile processing (e.g., non‑shrink treatment for wool) and certain surface cleaning or stainless steel cleaning applications. Usage patterns emphasize dry formulations (tablets, pucks, granules) where controlled slow dissolution provides released chlorine for disinfection.
Role in Synthesis or Formulations
- TCCA serves as a source of available chlorine and as an oxidant or halogenating reagent in some chemical processes. It is incorporated into multi‑component formulations with other biocides or buffering agents to modulate dissolution and stability.
- Typical manufacturing: produced commercially by chlorination of trisodium cyanurate (or by reaction of hypochlorous acid/chlorine with cyanuric acid monosodium salt). Formulations combine TCCA with diluents or stabilizers (cyanuric acid or salts) to adjust available chlorine content and dissolution rate.
- Representative formulated products include multi‑ingredient tablets and pucks where specified percentages of trichloro‑ and dichloro‑triazinetriones are combined with binders or carriers.
If a concise application summary is required for a specific product, selection is typically based on available chlorine content, particle size/disintegration profile and impurity limits appropriate for the intended use.
Safety and Handling Overview
Acute and Occupational Toxicity
Key toxicological and hazard metrics: - Oral LD50 (rat): \(406\,\mathrm{mg}\,\mathrm{kg}^{-1}\) (one reported value) and \(750\,\mathrm{mg}\,\mathrm{kg}^{-1}\) (alternate reported value). - Dermal LD50 (rabbit): \(>2000\,\mathrm{mg}\,\mathrm{kg}^{-1}\) (reported) and an historical entry of 20,000 mg/kg for one skin test. - Inhalation: reported LC (rat) \(>2000\,\mathrm{mg}\,\mathrm{m}^{-3}\)/1 h (indicative of low gas/vapor inhalation toxicity in that test but particulate exposure causes irritation). - Reported acute hazard profile includes harmful if swallowed, causes serious eye irritation and respiratory irritation; material is very toxic to aquatic life with long lasting effects.
Clinical and occupational effects include ocular and respiratory irritation, potential for corrosive injury to mucous membranes and stomach on ingestion, and reported cases of pulmonary effects following high exposures. Particulate dust may rapidly reach harmful airborne concentrations in poorly controlled packaging or handling operations.
Personal protective equipment and emergency response: - Use appropriate dust control, local exhaust and respiratory protection for particulate exposures. - Eye protection and chemical‑resistant gloves are required for handling; positive pressure SCBA is recommended for emergency response to fires or large releases. - First aid measures: remove to fresh air for inhalation; flush eyes and skin with water for at least 15–20 minutes; do not induce vomiting after ingestion and seek medical attention promptly.
Always consult product‑specific safety documentation for the intended grade and formulation.
Storage and Handling Considerations
Primary control measures: - Store dry, in a cool, well‑ventilated location, separated from combustibles, reducing agents, organic materials, ammonia/amines and hypochlorites. Avoid storage in areas where water ingress or drainage to sewers can occur. - Packaging: moisture‑excluding drums or lined pails are typical to prevent hydrolysis and loss of available chlorine. Keep containers closed and protected from physical damage. - Fire and spill response: although not combustible, TCCA is an oxidizer that can intensify fires involving other materials. If involved in fire, decomposition can generate toxic gases (chlorine, nitrogen trichloride); containers may rupture on heating. - Spill control: avoid water ingress to spilled material where possible; collect dry spills into clean, dry containers using noncombustible absorbents (vermiculite, sand), segregate and neutralize with appropriate reducing agents under controlled conditions if required. Prevent release to water bodies; the material is very toxic to aquatic organisms. - Disposal: neutralize residual oxidizing capacity (for example with reducing agents under controlled conditions) before disposal where allowed by local regulations; consult waste management authorities for permitted routes.
For detailed hazard, transport and regulatory information, users should refer to the product‑specific Safety Data Sheet (SDS) and local legislation.
Emergency Response and First Aid (summary)
- Inhalation: move to fresh air, provide oxygen if breathing is difficult, seek medical care.
- Eye contact: flush immediately with copious water for at least 15–20 minutes and obtain medical attention.
- Skin contact: rinse with water and remove contaminated clothing; obtain medical attention for persistent irritation or burns.
- Ingestion: do not induce vomiting; rinse mouth and give water if the patient is conscious; seek immediate medical attention.
- Firefighting: use large volumes of water for fire suppression and cooling of containers; approach fire from upwind; fire may evolve toxic chlorine and nitrogen oxides — use full protective equipment and SCBA.
This document summarizes critical physicochemical, use and hazard characteristics of trichloroisocyanuric acid for technical and industrial audiences. For product procurement, specification development, quality control testing, or process integration, consult formula‑specific technical datasheets, SDS, and applicable regulatory guidance to ensure compliance with handling, storage and disposal requirements.
