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Send EmailSodium Sulfohydrate, Sodium Sulfhydrate, Sodium Bisulfide, Sodium Hydrogen Sulfide, Sodium Bisulphide (anhydrous), Sodium Hydrosulfide, 16721-80-5
Sodium Hydrosulfide
CAS No: 16721-80-5
Molecular Formula: HNaS
Molecular Weight: 56.06 g/mol
Synonyms: Sodium Sulfohydrate, Sodium Sulfhydrate, Sodium Bisulfide, Sodium Hydrogen Sulfide, Sodium Bisulphide (anhydrous)
1. Chemical Identification & Classification
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IUPAC Name: Sodium hydrosulfide
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Chemical Class: Inorganic sulfide compound, strong base
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EINECS No: 238-213-8
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UN No: 2949 (solid) / 2948 (aqueous solution)
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Hazard Class: 4.2 (Spontaneously combustible solid) + 8 (Corrosive) – for solution: Class 8 only
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Packing Group: II
2. Physical & Chemical Properties (Solid Anhydrous Form)
| Parameter | Value |
|---|---|
| Physical State | Colorless to off-white needle-like crystals (pure); industrial grade yellow/orange |
| Odor | Rotten eggs (H₂S) |
| Melting Point | 55°C (131°F) |
| Flash Point | 90°C (194°F) (closed cup) |
| Density (20°C) | 1.79 g/cm³ |
| Water Solubility (20°C) | 620 g/L (excessive dissolution, exothermic) |
| pH (1% aqueous solution) | 10 – 12 (strongly alkaline) |
| Hygroscopicity | High (rapidly absorbs ambient moisture) |
| Autoignition | Fine dust can ignite in air |
| Vapor Pressure (20°C) | Negligible (solid); H₂S vapor released from solution |
3. Thermal Properties & Decomposition
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Thermal Decomposition Onset: Melts at >55°C; slow decomposition >150°C; decomposes into H₂S and sodium sulfites >200°C.
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Boiling Point (solution): 100 – 115°C depending on concentration.
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Freezing Point (solution): -10°C to -5°C for 32% solution.
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Specific Heat Capacity (solid): Approx. 1.2 J/g·K (25°C)
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Enthalpy of Solution (in water): Exothermic (≈ -62 kJ/mol)
4. Reactivity Profile & Incompatibilities
| Substance Class | Reaction Type | Consequence |
|---|---|---|
| Strong Acids (HCl, H₂SO₄, HNO₃) | Violent exothermic | Instant H₂S gas release (toxic, flammable) |
| Oxidizers (KMnO₄, peroxides, chromates) | Violent oxidation | Fire, explosion, SO₂ formation |
| Heavy Metal Salts (Cu, Ag, Hg, Pb) | Precipitation reaction | Insoluble metal sulfides + heat |
| Water (with humid air) | Hydrolysis | H₂S vapor + NaOH (exothermic) |
| Active Metals (Al, Zn, Mg) | Corrosion + hydrogen gas | H₂ gas formation (flammable, explosive) |
| Halogens (Cl₂, Br₂) | Redox reaction | Elemental sulfur and hydrogen halide |
5. Stability & Storage Conditions
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Stability: Stable but highly hygroscopic and air-sensitive.
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Storage Temperature: 0 – 30°C, ideally 15 – 25°C.
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Storage Atmosphere: Under dry inert gas (nitrogen or argon).
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Suitable Storage Materials: Stainless steel (316L), HDPE, PTFE-lined containers, glass (small quantities).
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Materials to Avoid: Acids, oxidizers, zinc, aluminum, copper, brass, galvanized steel.
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Shelf Life: 12-24 months (solid), 6-12 months (solution) under proper conditions.
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Storage Warning: Keep away from direct sunlight and heat sources. Store separately from oxidizers and acids.
6. Physical Hazards & Flammability Details
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Flammability Class: Combustible solid (OSHA Class II, NFPA Class 2)
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Ignition Temperature: 90°C (flash point applies to solution; molten solid is flammable)
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Self-Heating Property: Can gradually heat when in contact with air, especially in humid conditions. Risk of spontaneous combustion in large piles (Hazard Class 4.2).
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Dust Explosion: Finely divided solid can form explosive mixtures in air with ignition source (Minimum Explosion Concentration ≈ 60 g/m³).
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Combustion Products: Sulfur dioxide (SO₂), hydrogen sulfide (H₂S), sodium oxide (Na₂O)
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Fire Extinguishing Media: Water fog, dry chemical powder, CO₂ – Do NOT apply direct high-pressure water jet onto flames (releases H₂S).
7. Analytical Test Methods & Quality Control
| Test Parameter | Method | Standard |
|---|---|---|
| Purity (%NaHS) | Iodometric titration | ISO 10634, ASTM D5356 |
| Sodium Hydroxide (NaOH) | Acid-base titration (pH-metric) | ASTM D4662 |
| Sodium Sulfide (Na₂S) | Methylene blue colorimetric / Potentiometric | EPA 376.2 |
| Sodium Carbonate (Na₂CO₃) | Acid-base titration (phenolphthalein + methyl orange) | ISO 3196 |
| Water Insoluble Matter | Gravimetric (0.45 µm filter) | ISO 2479 |
| Color (APHA) | Spectrophotometric (400 nm) | ASTM D1209 |
| Iron (Fe) | Atomic Absorption Spectroscopy (AAS) | ISO 11885 |
| Density (20°C) | Densitometer or pycnometer | ASTM D4052 |
8. Typical Impurity Limits (Industrial Grade - 32% Aqueous Solution)
| Parameter | Value (max.) |
|---|---|
| Sodium Carbonate (Na₂CO₃) | 1.5% by weight |
| Sodium Sulfite (Na₂SO₃) | 0.5% |
| Sodium Sulfate (Na₂SO₄) | 0.3% |
| Sodium Thiosulfate (Na₂S₂O₃) | 0.2% |
| Sodium Hydroxide (NaOH, free) | 0.5 – 1.5% |
| Iron (Fe) | 10 ppm |
| Heavy Metals (Pb + Cu + Hg) | 5 ppm |
| Water | 67 – 68% (balance) |
9. Toxicology Profile
| Parameter | Value | Remarks |
|---|---|---|
| Acute oral toxicity (rat, LD₅₀) | 30 – 50 mg/kg | Toxic (GHS Class 3) |
| Acute dermal toxicity (rabbit, LD₅₀) | > 200 mg/kg | Low dermal toxicity |
| Acute inhalation (rat, LC₅₀, as H₂S) | 444 ppm (4 hours) | High inhalation toxicity |
| Skin corrosion/irritation | Corrosive (pH > 11.5) | Irreversible damage |
| Eye damage | Severe, irreversible | Corneal opacity, conjunctivitis |
| Skin sensitization | Not sensitizing | Alkaline irritation present |
| Chronic toxicity | Limited data | Neurological effects related to H₂S upon repeated exposure |
| Mutagenicity | Negative (Ames test) | No genetic damage |
| Carcinogenicity | IARC: Not classified | Insufficient data |
10. Ecotoxicology & Environmental Impact
| Parameter | Value | Organism/Duration |
|---|---|---|
| Fish LC₅₀ | 0.05 – 0.2 mg/L (as total sulfide) | Rainbow trout, 96 hours |
| Daphnia magna EC₅₀ | 0.1 mg/L | Water flea, 48 hours |
| Algae EC₅₀ | 0.3 mg/L | Selenastrum capricornutum, 72 hours |
| Microbial toxicity | Inhibition in range 10 – 50 mg/L | Activated sludge (ISO 8192) |
| Bioconcentration Factor (BCF) | Low (log Kow ≈ -0.8) | Bioaccumulation not expected |
| Soil Mobility | High (anionic form) | High risk of groundwater migration |
| Biodegradation | Abiotic (converts to H₂S gas in acidic media) | Forms SO₂ in atmosphere |
| Aquatic toxicity class (WGK) | 3 (Germany) – Very hazardous to water | Water pollutant |
11. Exposure Control & Personal Protective Equipment (PPE)
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Occupational Exposure Limit (H₂S, ACGIH TWA): 10 ppm (14 mg/m³)
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Short Term Exposure Limit (STEL): 15 ppm (15 minutes)
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Odor Threshold (H₂S): 0.005 – 0.01 ppm (rotten egg smell at low concentration; odor paralysis at high concentration)
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Engineering Controls: Local exhaust ventilation, closed system processing, continuous H₂S detector (personal and area monitor)
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Respiratory Protection: Acid gas cartridge full-face mask (for H₂S) or positive pressure SCBA – above 10 ppm
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Gloves: Butyl rubber, Viton or Nitrile (≥ 0.4 mm thickness); disposable gloves are NOT sufficient
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Eye Protection: Chemical-resistant full seal safety goggles (against splashes) + face shield
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Skin Protection: Butyl rubber or PVC apron, chemical-resistant boots
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Eye Wash & Safety Shower: Mandatory in work area
12. Emergency Response & First Aid
| Exposure Type | Emergency Response |
|---|---|
| Skin contact | Remove contaminated clothing immediately. Wash with plenty of water for at least 15 minutes. Seek medical attention if burned. |
| Eye contact | Rinse with lukewarm water for at least 15 minutes keeping eyelids open. Immediate medical attention. |
| Ingestion | Do NOT induce vomiting (risk of H₂S aspiration!). Rinse mouth. If conscious, drink 1-2 glasses of water. Seek medical aid. |
| Inhalation | Move to fresh air. If breathing stopped, give artificial respiration (avoid mouth-to-mouth – toxic!). Administer oxygen. Seek medical aid. |
| Small spill | Cover with absorbent (sand, sawdust, vermiculite). Never use acids. Place in closed labeled waste container. |
| Large spill | Evacuate area. Stop leak if possible. Contain with soil or sand. Authorized disposal. |
| Fire | Water fog, dry chemical powder, CO₂, alcohol foam. Do not apply direct water jet onto flames (releases H₂S and SO₂). Cool containers with water. |
13. Applications & Industrial Uses
| Sector | Application | Details |
|---|---|---|
| Leather Industry | Liming, unhairing | Dissolving hair without damaging hide structure; pre-tanning process |
| Dyes & Textiles | Sulfur dye synthesis | Reducing agent for black, blue, brown sulfur dyes |
| Mining | Flotation modifier | Separation of sulfide minerals in copper, molybdenum, lead ores |
| Chemical Synthesis | Intermediate | Pesticides (ethyl mercaptan), ammonium sulfide, thioglycolate, organosulfur compounds |
| Wastewater Treatment | Heavy metal precipitation | Cu, Hg, Pb, Cd, Zn precipitated as sulfides and removed |
| Pulp & Paper | Kraft process (white liquor) | Sulfur source for lignin dissolution in pulp |
| Petrochemicals | Catalyst protection | On-site H₂S generation without poisoning hydrogenation catalysts; catalyst regeneration |
| Fertilizers | Desulfurization | Removal of monomeric sulfur from activated carbon |
| Rubber | Vulcanization accelerator | Intermediate for some rubber chemicals |
| Photography | Fixer component | Dissolving silver salts (historical application) |
14. Packaging Options & Logistics
| Package Type | Material | Net Weight | Suitability |
|---|---|---|---|
| Solid (flakes/crystals) – Bag | Multi-layer kraft + PE inner liner | 25 kg, 50 kg | Dry environment, inert atmosphere |
| Solid – Drum | HDPE drum (gasketed lid) | 100 kg, 200 kg | Long-term storage |
| Solution – IBC | 1000 L HDPE IBC (with bottom valve) | ~1200 kg | Dilute alkali protection |
| Solution – Drum | HDPE drum (bunghole lid) | 200 kg, 250 kg | Small quantities |
| Solution – Tanker | Stainless steel (316L) or carbon steel + rubber lining | 15 – 25 tons | Bulk transport, heated option |
| HS Code: 2830.10 | Class: 4.2/8 | UN No: 2949 (solid), 2948 (solution) | Packing Group: II |
15. Transport & Shipping Regulations
| Transport Mode | Special Requirements | |
|---|---|---|
| Road (ADR/RID) | Class 4.2 + 8, UN 2949/2948, Packing Group II, Transport code (E) – self-heating | |
| Rail (RID) | Same as ADR; ventilation required in rail wagon | |
| Marine (IMDG) | Marine Pollutant (MP) mark; keep upright, protected from sunlight | |
| Air (ICAO/IATA) | Solid form only (UN 2949); forbidden on passenger aircraft – cargo only | |
| IATA Packing Instruction | 465 (solid) | Limited Quantity: 5 kg |
| Marine Pollutant | Yes (MP) | EmS (Emergency Schedule): F-A, S-J |
16. Regulatory Compliance Information
| Regulation / Inventory | Status | Notes |
|---|---|---|
| EU REACH (EC 1907/2006) | Registered (existing) | EC No: 238-213-8 |
| EU CLP (EC 1272/2008) | Class 4.2, 8 | Pictograms: GHS05, GHS06, GHS09 |
| TSCA (USA) | Listed | Active |
| EINECS | Listed | 238-213-8 |
| Canada DSL | Listed | |
| China IECSC | Listed | |
| Australia AICS | Listed | |
| Japan ENCS | Listed | |
| Korea KECI | Listed | |
| Turkey KKDIK (REACH) | Registration required | According to local regulation |
17. Disposal & Waste Management
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Waste Code (European Waste Catalogue - EWC): 06 02 04* (hazardous waste – alkaline waste without metal hydroxide) or 06 13 02* (hazardous waste – inorganic sulfides)
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Disposal Method: Neutralization (careful conversion to H₂S gas with dilute acid, then gas incineration or alkaline scrubbing) + solid waste landfill
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Wastewater Discharge: According to local sewer regulations (typically total sulfide < 1 mg/L) – treatment mandatory
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Alternative: Licensed hazardous waste incinerator (with SO₂ capture by alkaline scrubbing)
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Do NOT: Contact directly with acids, pour down drains, allow to leach into soil
18. Quality Certification & Testing Frequency
| Quality Parameter | Testing Frequency | Acceptance Criteria |
|---|---|---|
| Purity (%NaHS) | Each batch | ≥ 70% (industrial solid), ≥ 31.5% (industrial solution) |
| NaOH and Na₂S content | Each batch | NaOH ≤ 1.5%, Na₂S ≤ 0.5% |
| Color (APHA) | Each batch | ≤ 200 |
| Density (20°C) | Each batch | 1.20 – 1.30 g/cm³ (32% solution) |
| Heavy metals (Pb, Cu, Hg) | Monthly | Each ≤ 2 ppm |
| Water insoluble matter | Monthly | ≤ 0.1% |
| Packaging integrity | Each shipment | No leakage, label legible |
| Long-term stability | Annually | Purity drop < 2% after 6 months |
19. Supply Chain & Storage Facility Requirements
| Parameter | Requirement |
|---|---|
| Storage tank material | Stainless steel (316L) or rubber-lined carbon steel |
| Tank fill level | Max. 90% (for thermal expansion) |
| Tank ventilation | Inert gas blanketing (N₂) + H₂S scrubber (alkaline washer) |
| Temperature control | Jacketed tank (cooling/heating), 15-25°C range |
| Solution transfer line | 316L SS or HDPE, leak-proof pump (magnetic drive) |
| Emergency equipment | H₂S detector, emergency shower, eye wash, neutralization solution (NaOH) |
| Personnel training | H₂S hazards, confined space entry, PPE usage |
20. Summary – Critical Safety & Handling Warnings
| Topic | Warning / Information |
|---|---|
| Primary hazard | Contact with acids → immediate H₂S gas (toxic, flammable, lethal) |
| Secondary hazard | Self-heating and spontaneous combustion (especially in humid air) |
| Odor warning | Rotten egg smell at low levels (0.01 ppm); odor paralysis at high levels (100 ppm) |
| Lethal H₂S concentration | 500 – 1000 ppm → immediate loss of consciousness and death |
| NEVER do | Mix with acids, use near open flame, pour down drains |
| ALWAYS do | Ensure ventilation, H₂S detector, proper PPE, emergency plan |
| When purchasing | Check impurity levels (especially Na₂S and color), stability, supplier's SDS/TDS |
Note: This Technical Data Sheet (TDS) is for general informational purposes. Specifications may vary by manufacturer, batch, and local regulations. Always refer to your supplier's current Safety Data Sheet (SDS) and Technical Data Sheet before using the product. This document is designed for use by trained professionals.
Comparative Analysis of Sodium Sulfide and Reducing Chemicals
1. General Comparison Table
| Property | Sodium Hydrosulfide (NaHS) | Sodium Sulfide (Na2S) | Sodium Dithionite (Hydrosulfite) | Sodium Metabisulfite | Rongalite C | Decolite | Sodium Borohydride | Calcium Hydrosulfite |
|---|---|---|---|---|---|---|---|---|
| CAS No | 16721-80-5 | 1313-82-2 | 7775-14-6 | 7681-57-4 | 149-44-0 / 6035-47-8 | 149-44-0 derivative | 16940-66-2 | 6035-47-8 |
| Molecular Formula | HNaS | Na2S | Na2S2O4 | Na2S2O5 | CH3NaO3S·2H2O | NaHOCH2SO2 (modified) | NaBH4 | Ca(HSO2)2 |
| Molecular Weight | 56.06 g/mol | 78.04 g/mol | 174.11 g/mol | 190.11 g/mol | 154.14 g/mol (dihydrate) | ~154 g/mol | 37.83 g/mol | 170.18 g/mol |
| Water Solubility (20°C) | 620 g/L | 180 g/L | 210 g/L | 540 g/L | ~600 g/L | High | 550 g/L | Moderate |
| Aqueous pH (1%) | 10-12 (basic) | 12-13 (strong basic) | 5-7 (neutral, decomposes) | 4-5 (acidic) | 9.5-10.5 (basic) | 7-9 (neutral) | ~10 (basic) | 6-8 (neutral) |
| Melting Point | 55°C | >50°C (hydrolyzes) | 52°C (decomposes) | 150°C (decomposes) | 64.5°C (dihydrate) | 63-64°C | 300°C (decomposes) | 60°C (decomposes) |
| Primary Function | Sulfur source | Base, sulfur source | Strong reducing agent | SO2 source | Acidic reductant | Discharge print reductant | Very strong reducing agent | Bleaching |
2. Detailed Profile of Rongalite C and Decolite
2.1 Rongalite C (Sodium Formaldehyde Sulfoxylate - SFS)
Rongalite C is a BASF-registered brand name for sodium hydroxymethanesulfinate (NaHOCH2SO2). It is available as a white crystalline powder, typically as a dihydrate.
Key Properties:
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Chemical Class: Sulfoxylate salt (formaldehyde + sulfoxylic acid)
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Appearance: Colorless crystals or white powder
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Density (dihydrate): 1.75 g/cm3
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Stability: Stable in alkaline and neutral media; decomposes in acidic media releasing formaldehyde and SO2
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GHS Classification: H341 (suspected genetic damage)
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Flash Point: >100°C
2.2 Decolite
Decolite is a specialized derivative of the Rongalite C family, optimized for textile discharge printing applications.
Key Properties:
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Chemical Structure: Sodium formaldehyde sulfoxylate-based, modified formulation
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Primary Use: Discharge printing (patterned whitening) and vat dye reduction
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Advantages: Faster dissolution and lower temperature activation compared to standard Rongalite C
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Appearance: White crystalline powder
2.3 Rongalite C vs Decolite vs Bruggolite E01
| Property | Rongalite C | Decolite | Bruggolite E01 |
|---|---|---|---|
| Form | Hard white solid (powder/lump) | White powder | Powder/granule (dust-free) |
| Active Content | ~98-100% | ~98% | ~98-100% |
| Dissolution Rate | Moderate | High | Very high (rapid) |
| pH Suitability | Alkaline stable | Acidic/alkaline | Acidic and alkaline |
| Primary Application | Vat dyeing, discharge printing | Discharge printing (primary) | Emulsion polymerization, textiles |
| Dust Control | Low | Moderate | Dust-free |
| Shelf Life | 24 months | 24 months | 24-36 months |
3. Reactivity and Stability Comparison
| Chemical | Air Stability | Reaction with Water | Reaction with Acids | Temperature Sensitivity | Main Decomposition Product |
|---|---|---|---|---|---|
| NaHS | Low (hygroscopic, releases H2S) | Exothermic, stable | Violent H2S gas | >55°C melts, >200°C decomposes | H2S, Na2S |
| Na2S | Moderate (hygroscopic) | Violent exothermic, releases H2S | Violent H2S gas | >50°C hydrolysis | H2S, NaOH |
| Na2S2O4 | Very low (self-heating) | Releases heat | Toxic SO2 gas | >40°C rapid decomposition | SO2, sulfate, S |
| Na2S2O5 | Low (releases SO2 in humid air) | Stable (forms bisulfite) | SO2 gas | >150°C decomposes | SO2, Na2SO4 |
| Rongalite C | Moderate | Stable | Formaldehyde + SO2 | >65°C decomposes | Formaldehyde, SO2 |
| Decolite | Moderate (good) | Stable | Formaldehyde + SO2 | >65°C decomposes | Formaldehyde, SO2 |
| NaBH4 | Very low (reacts with moisture) | Violent exothermic, H2 gas | Violent H2 gas | >300°C decomposes (dry) | H2, NaBO2 |
| Ca(HSO2)2 | Low (oxygen sensitive) | Stable (in solution) | SO2 + H2S | >60°C decomposes | SO2, CaSO4 |
4. Industrial Applications - Detailed Comparison
| Application Area | NaHS | Na2S | Na2S2O4 | Rongalite C | Decolite | NaBH4 |
|---|---|---|---|---|---|---|
| Flotation (Mining) | Primary | Secondary | No | No | No | No |
| Leather Tanning (Unhairing) | Primary | Primary | No | No | No | No |
| Textile - Indigo Reduction | No | No | Primary | Used | Used | Rare |
| Textile - Discharge Printing | No | No | No | Primary | Specialist | No |
| Textile - Vat Dyeing | No | No | Used | Widespread | Used | No |
| Paper Bleaching | No | No | Primary | No | No | Primary |
| Pulp and Paper (Kraft) | Primary | Primary | No | No | No | No |
| Emulsion Polymerization | No | No | No | Used (redox) | No | No |
| Rubber (Redox Activator) | No | No | No | Widespread | No | No |
| Wastewater Treatment | Metal ppt | Metal ppt | Cr(VI) reduction | No | No | No |
| Pharmaceuticals (Antioxidant) | No | No | No | Used | No | No |
5. Selection Criteria for Rongalite C and Decolite
| Requirement | Best Choice | Reason |
|---|---|---|
| Patterned whitening in textile (discharge printing) | Decolite | Specifically developed for this application; high efficiency |
| Reducing agent for vat dyeing | Rongalite C or Sodium Dithionite | Both effective; Rongalite is more stable |
| Low-temperature polymerization (5°C SBR) | Bruggolite E01 (Rongalite derivative) | Special formulation that activates in the cold |
| Dust control is important | Decolite or Bruggolite E01 | Dust-free or low-dust formulations available |
| Formaldehyde-free reducing agent needed | Formaldehyde-free series | Rongalite C and Decolite release formaldehyde |
| FDA-compliant food-contact polymer | Bruggemann FF6 M | Formaldehyde-free, FDA approved |
6. Safety and Toxicology Comparison
| Chemical | Primary Hazard | GHS Pictograms | Special Risks | Skin Corrosivity |
|---|---|---|---|---|
| NaHS | H2S gas, corrosive | GHS05, GHS06, GHS09 | Self-heating | Yes (pH>12) |
| Na2S2O4 | Self-heating, eye damage | H251, H318, H402 | Heats in moist air, SO2 | No (not corrosive) |
| Rongalite C | Formaldehyde risk (H341) | H341 (suspected genetic damage) | Formaldehyde + SO2 with acids | No (pH 9.5-10.5) |
| Decolite | Formaldehyde risk | H341 | Formaldehyde + SO2 with acids | No |
| NaBH4 | Hydrogen gas, flammable | GHS02, GHS05 | H2 gas with water | Yes (alkaline) |
7. Summary - When to Use Which Chemical?
| Situation | Recommended Chemical | Reason |
|---|---|---|
| Copper/molybdenum flotation | NaHS | Low NaOH by-product, controlled H2S |
| Indigo dye reduction (denim) | Na2S2O4 or Rongalite C | High reduction power |
| Textile discharge printing (patterned whitening) | Decolite | Special formulation, high efficiency |
| Vat dyeing | Rongalite C or Na2S2O4 | Industry standard |
| Emulsion polymerization (SBR, NBR) | Bruggolite E01 | Cold activation, dust-free form |
| Paper bleaching | Na2S2O4 | Most commonly used |
| Food-contact applications | Formaldehyde-free reducing agent | FDA approved, no formaldehyde |
| Low-cost base | Na2S | Cheapest option |
| Strong reduction (organic synthesis) | NaBH4 | Unique reduction power |
8. Quick Chemical Comparison Table (Pocket Version)
| Chemical | Best For | Avoid For |
|---|---|---|
| NaHS | Flotation, leather, kraft pulp | Food, acidic environments |
| Na2S2O4 | Indigo, paper bleaching | Long-term storage, high temperature |
| Rongalite C | Vat dyeing, discharge printing, rubber polymerization | Formaldehyde-sensitive applications |
| Decolite | Discharge printing (textile) | Formaldehyde-sensitive applications |
| NaBH4 | Organic synthesis, specialty reduction | Aqueous solutions (reacts), high cost |
9. Critical Warning: Formaldehyde Release
IMPORTANT: Rongalite C and Decolite release formaldehyde (IARC Group 1 carcinogen) under acidic conditions or at elevated temperatures.
-
Safe handling: Always use with adequate ventilation
-
pH control: Keep pH above 7 during use
-
PPE requirement: N95 mask, chemical goggles, nitrile gloves
-
Alternatives available: Bruggemann formalin-free series (FF6 M, FF7) for formaldehyde-sensitive applications
Conclusion
| Chemical | Best Application Domain |
|---|---|
| NaHS (Sodium Hydrosulfide) | Flotation, leather tanning, kraft pulp industry standard |
| Rongalite C | Controlled reduction in textile (vat dyeing, discharge printing) and rubber polymerization |
| Decolite | Optimized derivative for textile discharge printing (patterned whitening) |
| Formaldehyde-free alternatives | Food-contact, pharmaceutical, and sensitive applications |
Note: This comparative analysis is for general informational purposes. Specifications may vary by manufacturer and batch. Always refer to your supplier's current Technical Data Sheet (TDS) and Safety Data Sheet (SDS) before use.
