Sodium Dichloroisocyanurate, Troclosene Sodium, Chlor, SDIC, NaDCC, DCCNa, 2893-78-9, 51580-86-0

Sodium Dichloroisocyanurate, Troclosene Sodium, Chlor, SDIC, NaDCC, DCCNa, 2893-78-9, 51580-86-0

SDIC (SODIUM DICHLOROISOCYANURATE)

1. PRODUCT DEFINITION AND CHEMICAL IDENTITY

2. PHYSICAL AND CHEMICAL PROPERTIES

3. REACTION MECHANISM AND MODE OF ACTION

SDIC undergoes controlled hydrolysis when dissolved in water, releasing hypochlorous acid (HOCl) , the active disinfectant species, and cyanuric acid, which acts as a stabilizer:

C₃Cl₂N₃NaO₃ + 2 H₂O → 2 HOCl + C₃H₃N₃O₃ (Cyanuric Acid) + Na⁺

• Disinfection: The resulting hypochlorous acid (HOCl) is a powerful oxidant. It oxidises the cell walls of microorganisms, denatures proteins, disrupts enzyme functions, and rapidly inactivates them. It exhibits a broad spectrum of activity against bacteria, viruses, fungi, and algae.

• Stabilization (UV Protection): The released cyanuric acid protects free chlorine from the degrading effects of UV light. This allows chlorine to remain active for a much longer time, especially in outdoor swimming pools.

• pH Effect: The pH of an SDIC solution is generally in the range of 5.5–7.0. In this pH range, the HOCl form, which has the highest disinfection power, is predominant.

• Controlled Release: SDIC releases chlorine gradually upon dissolution, not all at once. This prevents a sudden chlorine shock and provides longer-lasting, more stable disinfection.

4. ALTERNATIVE NAMES AND SYNONYMS

• SDIC

• Sodium Dichloroisocyanurate

• Troclosene Sodium (INN)

• NaDCC

• DCCNa

• Dichloro-s-triazinetrione sodium salt

5. PRODUCTION METHOD (Summary)

SDIC production takes place in three main stages:

1. Cyanuric Acid Production: Cyanuric acid is obtained by the high-temperature pyrolysis of urea.

2. Dichlorination: Cyanuric acid is reacted with chlorine gas in an aqueous phase to form dichloroisocyanuric acid.

3. Neutralization and Drying: The resulting acid is neutralized with sodium hydroxide (NaOH) to form the sodium salt of SDIC. The product is then crystallized, dried, and brought into the desired form (powder, granules, tablets).

6. SECTORAL APPLICATIONS AND USAGE RATES

7. MANDATORY / IRREPLACEABLE APPLICATIONS FOR SDIC

In the following situations, SDIC provides a distinct advantage over its alternatives and is critically important:

• Outdoor Swimming Pools: Thanks to the buffering effect of cyanuric acid, it protects chlorine from UV light. While alternatives like calcium hypochlorite degrade rapidly under UV, SDIC provides long-lasting protection.

• Emergency / Disaster Area Water Disinfection: Its lightweight, portable, long-shelf-life, and fast-dissolving tablet form is ideal for providing safe drinking water in emergencies like earthquakes and floods.

• Mobile Military and Field Water Treatment Units: Its compact structure and ease of dosing offer a reliable disinfection solution in mobile units.

• Rural and Off-Grid Drinking Water Systems: Its high efficacy at low doses and applicability with simple equipment make it suitable for areas without access to centralized treatment plants.

8. ALTERNATIVES AND COMPARISON

9. REGULATORY STATUS, SAFETY, AND STORAGE

• GHS Classification (CLP Regulation):

  • Signal Word: Danger

  • Hazard Statements: H272 (May intensify fire; oxidizer), H302 (Harmful if swallowed), H319 (Causes serious eye irritation), H335 (May cause respiratory irritation), H410 (Very toxic to aquatic life with long lasting effects).

  • Precautionary Statements: P210, P220, P261, P264, P273, P280, P301+P312, P305+P351+P338.

• Drinking Water Approval: Approved by WHO and EPA as an emergency drinking water disinfectant. Compliance with national legislation should be checked for routine use.

• Food Contact: Permitted for use on food processing surfaces in some countries under specific limits. Thorough rinsing of surfaces after use is mandatory.

• Storage:

  • Store in a cool (<30 °C), dry, and well-ventilated area in its tightly closed original packaging.

  • Keep away from heat, direct sunlight, flame, and sparks.

  • Strictly avoid contact with combustible materials, reducing agents, strong acids, nitrogenous compounds, and organic materials (risk of fire and explosion).

  • Protect from moisture; moisture can cause the product to decompose and release chlorine gas.

• Personal Protective Equipment (PPE): Wear protective gloves, goggles/face shield, and a dust mask. Ensure adequate ventilation.

• Packaging: Typically sold in 1–50 kg plastic buckets, 25–50 kg fibre drums, or 1000 kg big bags.

10. FREQUENTLY ASKED QUESTIONS

Q1: What is the difference between SDIC and TCCA?
Both belong to the chlorinated isocyanurate family. The fundamental difference is that SDIC is the sodium salt, while TCCA is the acid form. SDIC (55-60% available chlorine) dissolves faster in water and is ideal for shock chlorination. TCCA (90% available chlorine) dissolves more slowly and is suitable for long-term, slow-release chlorination (e.g., pool tablets).

Q2: Why is SDIC solution resistant to UV light?
When SDIC dissolves in water, cyanuric acid is released along with the disinfectant HOCl. Cyanuric acid acts as a "sunscreen," protecting free chlorine molecules from the degrading effects of UV light. This property makes SDIC unique for outdoor pools.

Q3: How is drinking water disinfected with SDIC tablets?
In an emergency, one standard SDIC tablet (typically 33 mg) is added to 1 litre of clear water, allowed to dissolve, and the water is left to stand for at least 30 minutes before drinking. If the water is cloudy, it should first be strained through a cloth or filter, and then 2 tablets should be used. The product instructions should be followed for precise dosage.

Q4: Which materials are incompatible with SDIC?
Contact with strong acids releases toxic chlorine gas. Contact with combustible materials, reducing agents (sulfite, bisulfite), ammonia, and amine-based compounds can lead to fire or explosion. Stainless steel and plastic (PE, PP, PVC) equipment can be used; ordinary steel and copper alloys may corrode.

Q5: What is the shelf life of SDIC?
Under proper storage conditions (cool, dry, sealed packaging), the shelf life of SDIC is at least 24 months. Moisture and high temperature are the main factors that shorten the shelf life.

11. QUICK REFERENCE TABLE