Chloramine T (CAS 127-65-1): A Solid Chlorine-Releasing Disinfectant and Oxidising Agent
Chloramine T is the sodium salt of N-chloro-p-toluenesulfonamide – a white crystalline powder that releases active chlorine and is used both as a disinfectant and as an oxidising reagent. It sits between the harsh liquid hypochlorites and the modern halogenated hydantoins: a solid, comparatively stable, chlorine-releasing chemistry. This article covers what it is, its specification, how it works, where it is used, and how it compares with other disinfectants.
1. What Chloramine T is
| Property | Value |
|---|---|
| Name | Chloramine T (N-chloro-p-toluenesulfonamide sodium salt) |
| CAS number | 127-65-1 |
| Formula / MW | C7H7ClNNaO2S / 227.64 g/mol (anhydrous; commonly supplied as the trihydrate) |
| Appearance | White crystalline powder |
| Active chlorine | About 28% (theoretical 29.6%) |
| Type | Chlorine-releasing (N-chloro) disinfectant and oxidiser |
The chlorine in Chloramine T is bound to nitrogen, not to oxygen as in hypochlorite. That difference – “combined” rather than “free” chlorine – is why it is more stable, less aggressive and slower-releasing than liquid bleach, with less chlorine odour and less damage to surfaces.
2. Specification
| Property | Specification | Why it matters |
|---|---|---|
| Appearance | White crystalline powder | Visual acceptance |
| Assay | 98 – 103% | Active content; sets the dose |
| Colour (5% solution) | 25 Pt-Co max | Solution clarity – matters for clean applications |
| Turbidity (0.5% solution) | 5 FTU max | Fines/insolubles in solution |
| pH | 8.0 – 10.3 | Alkaline solution; affects compatibility and dosing |
| Ethanol insolubles | 1.5% max | Purity indicator |
| Ortho isomer | 0.5% max | Controls para-isomer purity (the active form) |
| Carr index | 25% max | Powder flowability – for automatic dosing and tabletting |
3. How it works
- Releases active chlorine. In water it hydrolyses to give the active chlorinating species, which oxidises microbial cell components – the basis of its disinfecting action.
- Combined chlorine chemistry. Because the chlorine is bound to nitrogen, the release is slower and gentler than free chlorine, giving a longer-acting, lower-odour treatment.
- Oxidising power. The same chemistry makes Chloramine T an oxidising and chlorinating reagent in organic synthesis (oxidation of sulfides, chloramine formation, iodometric titrations).
4. How it is made
Industrially, Chloramine T is made by chlorinating p-toluenesulfonamide and converting it to the sodium salt. Purity control is important: the ortho isomer is limited (0.5% max) because it is not the active para form, and the assay, insolubles and colour reflect the quality of the chlorination and the crystallisation.
5. Applications
| Use | Role of Chloramine T |
|---|---|
| Drinking water and pools | Disinfection; slower-releasing combined chlorine |
| Food and beverage plants | CIP and equipment sanitation (dairies, breweries, food processing) |
| Medical and veterinary | Instrument, surface and equipment disinfection |
| Textile and pulp/starch bleaching | Oxidative bleaching |
| Chemical synthesis | Oxidising and chlorinating reagent; iodometric analysis |
| Odour control | Oxidation of odorous species |
6. Chloramine T vs other disinfectants
| Disinfectant | Form | Chlorine type | Notes |
|---|---|---|---|
| Chloramine T | Solid | Combined (N-chloro) | Stable, lower odour, slower release; also an oxidising reagent |
| Sodium hypochlorite | Liquid | Free chlorine | Cheap and fast; less stable, harsher, higher odour |
| 5,5-Dimethylhydantoin | Solid | Halogenated hydantoin | Slow-release chlorine/bromine for pools and cooling water |
| Quaternary ammonium (DDAC/BAC) | Liquid | Not chlorine | Surface-active biocides; different mode of action |
| Glutaraldehyde | Liquid | Not chlorine | Non-oxidising biocide for cooling water and oilfield |
Chloramine T is chosen where a solid, stable, low-odour chlorine source is wanted – and, in synthesis, where its more selective oxidising action is useful.
7. Dosage and use
| Application | Typical practice (starting point) |
|---|---|
| Water disinfection | Dosed to the required residual; set by the water and the target |
| Surface / equipment disinfection | Dilute solution (common working strengths about 0.1 – 1%); contact time per protocol |
| Synthesis | Stoichiometric, per the reaction |
Always set the dose and contact time by your disinfection protocol and confirm the residual – not by a book value.
8. Safety and handling
- Oxidiser. Keep away from acids, ammonia and reducing agents – contact with acid or ammonia releases chlorine/chloramine gas.
- Irritant. Use gloves, goggles and ventilation; avoid dust inhalation.
- Storage. Sealed, cool, dry and out of direct sunlight; separate from acids, ammonia and organics.
- Documentation. Follow the SDS for handling, first aid and transport classification.
9. Packaging and supply
| Item | Detail |
|---|---|
| Packaging | 25 kg PP/PE bags or drums; palletised for container shipment |
| Documents | Per-batch COA and SDS; third-party inspection on request |
| Delivery | FOB or CIF to your port; quote by tonnage |
Frequently Asked Questions
What is Chloramine T used for?
As a chlorine-releasing disinfectant (water, food plants, medical/veterinary) and as an oxidising and chlorinating reagent in chemical synthesis and analysis.
Is Chloramine T the same as chlorine bleach?
No. Bleach (sodium hypochlorite) supplies free chlorine; Chloramine T supplies combined (N-chloro) chlorine, which is more stable and slower-releasing, with lower odour and less surface damage.
What does the ortho isomer limit mean?
It controls the purity of the active para isomer – a low ortho content (0.5% max) means a cleaner, more consistent product.
How should Chloramine T be stored?
Sealed, cool, dry and out of sunlight, away from acids, ammonia and reducing agents. Contact with acid or ammonia releases chlorine/chloramine gas.
What is the active chlorine content?
About 28% (theoretical 29.6%) – confirm the assay on the batch COA.
Related reading
- Water treatment chemicals overview: coagulants, flocculants, biocides and dechlorination
- 5,5-Dimethylhydantoin as a precursor to halogenated hydantoin biocides
- DDAC vs benzalkonium chloride: quaternary ammonium biocides compared
- Glutaraldehyde in water treatment and oilfield biocide applications
- Chloramine T (CAS 127-65-1) – product page
PolyBlueChem supplies Chloramine T (CAS 127-65-1), white crystalline powder, assay 98-103%, with per-batch COA and SDS and FOB/CIF delivery. Contact us with your tonnage and delivery port.