Azodicarbonamide, Azobisformamide, Diazenedicarboxamide, Azodiformamide, ADCA, ADA, 123-77-3

Azodicarbonamide, Azobisformamide, Diazenedicarboxamide, Azodiformamide, ADCA, ADA, 123-77-3

AZODICARBONAMIDE (ADA)

Azodicarbonamide / Azobisformamide / E927a / ADA
CAS Number: 123-77-3
EC Number: 204-650-8
E Number: E927a

1. IDENTIFICATION INFORMATION

2. PHYSICAL PROPERTIES

3. CHEMICAL PROPERTIES

Molecular Structure:

H₂N - C - N = N - C - NH₂
       ||         ||
       O          O

Decomposition Reaction (Thermal):

C₂H₄N₄O₂  —[Heat 180-220°C]—> N₂↑ + CO↑ + NH₃↑ + CO₂↑ + H₂O

Decomposition Products:

Hydrolysis Reaction (with Acid or Base):

C₂H₄N₄O₂ + 2 H₂O  —[H⁺/OH⁻]—> Hydrazodicarbonamide (Hydrolysis)

Formation Reaction:

Hydrazine + Urea + Oxidation → Azodicarbonamide + H₂O

4. PRODUCTION PROCESS

Reaction Equations:

Step 1 (Hydrazodicarbonamide Formation):

N₂H₄ (Hydrazine) + 2 NH₂CONH₂ (Urea)  —[Heat]—> H₂NNHCONHCONH₂ (Hydrazodicarbonamide) + 2 NH₃

Step 2 (Oxidation to Azodicarbonamide):

H₂NNHCONHCONH₂ + [O]  —[Chlorine/Bromine/Air]—> N₂C₂H₄O₂ (Azodicarbonamide) + H₂O

Overall Reaction:

N₂H₄ + 2 NH₂CONH₂ + [O]  —[Heat]—> N₂C₂H₄O₂ + 2 NH₃ + H₂O

5. AVAILABLE GRADES AND SPECIFICATIONS

Typical Specifications (Technical Grade):

Typical Specifications (Food Grade):

6. APPLICATIONS

6.1. Plastics and Rubber Industry – Largest Use (Blowing Agent)

Blowing Agent Mechanism:

• Heating to 180-220°C causes decomposition

• Gas bubbles (N₂, CO₂, CO, NH₃) are released

• Bubbles form cells in the polymer matrix

• Results in lightweight, spongy, or foamed material

• Endothermic reaction (absorbs heat) helps control processing temperature

6.2. Food Industry (Flour Treatment – E927a)

Flour Treatment Benefits:

• Oxidizes flour components to improve baking properties

• Strengthens gluten network for better gas retention

• Improves loaf volume and crumb structure

• Bleaches carotenoids for whiter flour

• Reduces mixing time and improves dough machinability

6.3. Rubber Industry

6.4. Coatings and Adhesives

6.5. Other Applications

7. DECOMPOSITION CHARACTERISTICS

Factors Affecting Decomposition:

8. FOOD SAFETY AND REGULATORY STATUS

Food Safety Concerns:

• Decomposition products include semicarbazide (SEM)

• Semicarbazide is a suspected carcinogen

• Heating in flour produces urethane and other by-products

• Some studies link ADA to respiratory sensitization in workers

9. SAFETY AND HEALTH INFORMATION (GHS CLASSIFICATION)

10. HAZARD STATEMENTS (H-CODES)

11. SAFETY STATEMENTS (P-CODES)

12. TOXICOLOGICAL INFORMATION

Health Effects:

Regulatory Limits (Food Use):

13. FIRST AID MEASURES

14. FIRE FIGHTING MEASURES

15. ENVIRONMENTAL INFORMATION

16. STORAGE AND HANDLING

Handling Notes:

• Avoid generating dust (respiratory sensitizer)

• Use local exhaust ventilation

• Keep away from heat sources (premature decomposition)

• Store in a dry place (moisture can cause caking)

• Avoid contact with heavy metal salts (activators)

• Use appropriate PPE (dust mask, gloves, goggles)

• Keep containers sealed when not in use

17. TRANSPORT INFORMATION

Note: Some transport classifications may consider ADA as self-reactive substance if not properly stabilized.

18. REGULATORY INFORMATION

FDA Status (USA):

EU Status:

• Not permitted as a food additive (Regulation (EC) No 1333/2008)

• Industrial use (blowing agent) is permitted

• Classification: CLP Regulation (EC) No 1272/2008

19. OTHER NAMES AND SYNONYMS

Trade Names:

Database Identifiers:

20. SUMMARY AND IMPORTANT WARNINGS

SUMMARY:

Azodicarbonamide (ADA, C₂H₄N₄O₂, CAS 123-77-3) is a yellow to orange-red crystalline powder used primarily as a chemical blowing agent in the plastics and rubber industry and as a food additive (flour bleaching and dough conditioning agent, E927a). It is an azo compound with two amide groups. ADA decomposes endothermically at 180-220°C, releasing gases (N₂, CO, NH₃, CO₂) that form cells in polymers, making them lightweight and foamed. As a blowing agent, ADA is used in PVC, EVA, rubber, polyolefins, and polyurethane foams. As a food additive (E927a), it is used in flour to bleach carotenoids and condition dough (improves gluten strength, elasticity, and bread volume). However, ADA is banned as a food additive in the EU, Canada, Australia, Japan, and Turkey due to concerns about decomposition products (semicarbazide - SEM) and potential health risks. ADA is also known colloquially as the "yoga mat chemical" because it is used to produce foamed plastics for yoga mats and other products. The USA (FDA) still permits ADA as a flour treatment additive (up to 45 ppm). Important safety concerns: ADA is a respiratory sensitizer (may cause occupational asthma), skin sensitizer, and may cause eye irritation. Workers handling ADA dust must use appropriate respiratory protection.

Key Properties:

Main Application Areas:

Key Safety Points:

• RESPIRATORY SENSITIZER: May cause allergy or asthma symptoms (H334)

• SKIN SENSITIZER: May cause allergic skin reactions (H317)

• EYE IRRITANT: Causes serious eye irritation (H319)

• HARMFUL: Harmful if swallowed (H302)

• ORGAN DAMAGE: May cause lung damage through prolonged exposure (H373)

• DUST HAZARD: Avoid inhaling dust (use respiratory protection)

• FOOD BAN: Banned as food additive in EU, Turkey, Canada, Australia, Japan

• USA FDA: Approved in flour up to 45 ppm

• USE PPE: Dust mask (respirator), protective gloves, safety goggles, protective clothing

• VENTILATION: Use local exhaust ventilation

• STORAGE: Cool, dry, away from heat and strong oxidizers

IMPORTANT WARNINGS:

Food Safety - Regulatory Status: Azodicarbonamide is approved as a food additive (flour treatment agent) only in the USA under FDA regulation 21 CFR 172.806 (maximum 45 ppm in flour). It is BANNED as a food additive in the European Union, Turkey, Canada, Australia, Japan, and many other countries. If you are in the food industry outside the USA, do NOT use ADA as a food additive. If you are exporting food products containing ADA to countries where it is banned, reformulate your products accordingly. In Turkey, ADA is banned for food use under the Turkish Food Codex (Türk Gıda Kodeksi) and other relevant regulations.

Semicarbazide (SEM) Issue: When ADA is heated during baking, it decomposes partially to semicarbazide (SEM). SEM is a suspected carcinogen and has been linked to tumor formation in animal studies. The presence of SEM in bread has been a major reason for the ban in many countries. Although the levels are very low (ppb range), the precautionary principle has led to its prohibition in many jurisdictions. Semicarbazide is also classified as a genotoxic carcinogen in some studies.

Blowing Agent Applications: ADA is one of the most widely used chemical blowing agents for plastics and rubber. It is especially effective in:

• PVC (polyvinyl chloride) foam production (profiles, sheets, boards)

• EVA (ethylene-vinyl acetate) foam production (shoe soles, sports mats, toys)

• Rubber sponge production (seals, gaskets, insulation)

• Polyolefin foams (polyethylene, polypropylene)
  The endothermic decomposition of ADA (absorbs heat) helps control the temperature during processing, reducing the risk of overheating and providing uniform cell structure.

Decomposition Products - Toxic Gases: The decomposition gases from ADA include carbon monoxide (CO), ammonia (NH₃), nitrogen oxides (NOx), and hydrogen cyanide (HCN) in some conditions. While the primary decomposition products are N₂ and CO₂, the presence of CO, NH₃, and other toxic gases requires adequate ventilation during processing. High-temperature processing (>220°C) may also produce hazardous gases. Ensure adequate exhaust ventilation to remove decomposition gases from the workplace.

Respiratory Sensitization (Occupational Asthma): ADA is a well-known occupational respiratory sensitizer. Workers exposed to ADA dust (especially in plastic compounding and rubber manufacturing) can develop occupational asthma, characterized by wheezing, coughing, shortness of breath, and chest tightness. Once sensitized, even very low concentrations can trigger symptoms. Use local exhaust ventilation at dust-generating points. Use appropriate respiratory protection (N95 or higher for dust, HEPA-filtered respirators). Implement health surveillance for workers with potential exposure.

Skin Sensitization: ADA can also cause allergic contact dermatitis. Workers handling ADA dust should wear protective gloves (nitrile, neoprene, or butyl rubber) and protective clothing. If skin contact occurs, wash thoroughly with soap and water. Contaminated clothing should be removed and washed before reuse.

Activators - Lower Decomposition Temperature: The decomposition temperature of ADA can be significantly reduced by additives called "activators" (kickers). Common activators include zinc oxide (ZnO), zinc stearate, urea, and certain metal soaps. These additives can reduce the decomposition temperature from 200-220°C to as low as 150°C. This is useful for processing heat-sensitive polymers but also requires careful control to avoid premature decomposition. Do not mix ADA with activators unless specifically intended for the application.

Particle Size and Cell Structure: The particle size of ADA significantly affects the foam cell structure:

• Fine grades (2-5 µm): Fine, uniform cells (EVA foams, shoe soles)

• Standard grades (5-15 µm): Medium cells (general PVC foams)

• Coarse grades (10-30 µm): Large cells (PVC profiles)
  Choose the appropriate grade for your specific application to achieve the desired cell size and density.

Flour Treatment (USA Only): In the USA, ADA is used in flour to:

• Bleach carotenoids (creates white flour)

• Oxidize proteins (strengthens gluten)

• Improve dough machinability

• Increase loaf volume

• Improve crumb structure
  Maximum permitted level is 45 ppm in flour. However, many major food brands have voluntarily removed ADA from their products due to consumer pressure, even where it is legal. If you are in the food industry, consider consumer perception of ADA (the "yoga mat chemical" controversy) even if it is legally permitted.

Consumer Perception - "Yoga Mat Chemical": ADA has been widely publicized as the "yoga mat chemical" because it is used to produce foamed plastics for yoga mats, shoe soles, and other foam products. This association has led to significant consumer concern and negative publicity, especially when ADA is present in food products. Many major food manufacturers (including Subway) have removed ADA from their products due to public pressure, even where it remains legally permitted.

Environmental Considerations: ADA is not readily biodegradable. While its aquatic toxicity is low, its decomposition products (ammonia, nitrogen oxides, etc.) can be harmful to the environment if released in large quantities. Avoid discharge to surface waters, groundwater, or soil. Dispose of ADA waste through controlled incineration or at licensed waste treatment facilities.

Thermal Stability - Premature Decomposition: ADA can decompose prematurely if exposed to:

• Temperatures above 180°C

• Contact with activators (zinc oxide, zinc stearate, etc.)

• Contact with strong acids or bases

• Heavy metal ions (zinc, iron, copper)

• Prolonged exposure to light (UV degradation)
  Store ADA in a cool, dry place, away from heat sources and direct sunlight. Do not store near oxidizing agents or incompatible materials.

Important Disclaimer: This Technical Data Sheet (TDS) is for informational purposes only. For complete safety, handling, storage, and regulatory compliance information, always refer to the official Safety Data Sheet (SDS) provided by the manufacturer/supplier. Azodicarbonamide is banned as a food additive in the European Union, Turkey, Canada, Australia, Japan, and many other countries. Do NOT use ADA in food applications unless you are in a jurisdiction where it is permitted (primarily the USA) and you comply with all applicable regulations. ADA is a respiratory sensitizer and may cause occupational asthma. Use appropriate personal protective equipment and engineering controls to minimize exposure to dust. In case of spill or fire, follow emergency procedures. Seek immediate medical attention for respiratory symptoms or significant exposures. This document summarizes information from various sources and is not a substitute for technical expertise or site-specific safety assessments.