Ammonium Hydroxide is a solution of ammonia in water, serves a critical role in cosmetic formulations as a pH adjuster and buffering agent. Its ability to regulate acidity and enhance ingredient performance makes it invaluable in personal care products. In hair care formulations, it aids in cuticle opening for improved ingredient absorption, while in skin treatments, it helps maintain product stability and effectiveness.
CAS Number: 1336-21-6
Molecular Formula: H5NO
Synonyms:
- Ammonia aqueous
- Aqua ammonia
- Household ammonia
- Ammonia, monohydrate
+ 12 more…
- NH4OH
- HSDB 5125
- EINECS 215-647-6
- DTXSID4020080
- CHEBI:18219
- EC 215-647-6
- MFCD00066650
- NH3 water
- Ammonium aqueous (28% or less NH3)
- Ammonia solution 25%
- Ammonia water (JP18)
- NH3 H2O
Properties of Ammonium Hydroxide
Chemical Identifiers
| EC Number | 215-647-6 |
| UNII | 922638002 |
| InChIKey | VHUUQVKOLVNVRT-UHFFFAOYSA-N |
| SMILES | [NH4+].[OH-] |
| IUPAC Name | azanium;hydroxide |
| InChI | InChI=1S/H3N.H2O/h1H3;1H2 |
Physical and Chemical Properties
This compound is a clear, colorless liquid with ammonia concentrations up to 30%. Its strong alkaline properties and ammonia vapor emissions necessitate careful handling to avoid respiratory or eye irritation. Commonly used in cleaning agents, fertilizers, and cosmetic formulations, Ammonium Hydroxide’s ability to dissolve organic material and neutralize acids underscores its versatility.
| Property | Value |
| pH | 11.6 (1.0 N solution); 11.1 (0.1 N solution); 10.6 (0.01 N solution) |
| Odor | Strong, pungent, and suffocating odor |
| Taste | Acrid taste |
| Density | Approximately 0.90 g/cm³ at 25°C |
| Color/Form | Colorless liquid |
| Solubility | Soluble only in aqueous form |
| Corrosivity | Dissolves metals such as copper and zinc |
| Boiling Point | 38°C (25%) |
| Decomposition | Releases ammonia and nitrogen oxides when heated |
| Melting Point | -58°C (25%) |
| Vapor Density | 0.6 (air = 1) |
| Vapor Pressure | 2160 mm Hg at 25°C |
| Odor Threshold | Detectable at concentrations below 50 ppm as ammonia gas |
| Dissociation Constants | pKb = 4.767 at 20°C; pKb = 4.751 at 25°C; pKb = 4.740 at 30°C |
| Other Experimental Properties | Reacts exothermically with sulfuric acid and other strong acids, causing the mixture to become boiling hot. |
Structural Properties
Ammonium Hydroxide is a simple chemical compound with a molecular weight of around 35 g/mol. It contains two heavy atoms and can form hydrogen bonds, acting as both a donor and an acceptor. The compound is fully structured and does not have any isotopes or rotatable bonds, indicating its basic chemical simplicity.
It has a topological polar surface area, which is important for its interaction with other molecules. Overall, its structure is relatively straightforward and canonical, with no significant complexity or unusual bonding features.
| Property | Value |
| Complexity | 0 |
| Exact Mass | 35.037113783 g/mol |
| Formal Charge | 0 |
| Heavy Atom Count | 2 |
| Molecular Weight | 35.046 g/mol |
| Monoisotopic Mass | 35.037113783 g/mol |
| Isotope Atom Count | 0 |
| Rotatable Bond Count | 0 |
| Compound Is Canonicalized | Yes |
| Hydrogen Bond Donor Count | 2 |
| Hydrogen Bond Acceptor Count | 1 |
| Covalently-Bonded Unit Count | 2 |
| Topological Polar Surface Area | 2 Ų |
| Defined Atom Stereocenter Count | 0 |
| Defined Bond Stereocenter Count | 0 |
| Undefined Atom Stereocenter Count | 0 |
| Undefined Bond Stereocenter Count | 0 |
Uses of Ammonium Hydroxide in Cosmetics
Functional role in cosmetics:
- Ammonium Hydroxide is used as a Denaturant; Buffering agent in cosmetics.
Other uses:
- Primarily used as a pH regulator and process stabilizer.
- Applied as an etching agent.
- Found in various cleaning and personal care formulations.
- Also classified under the ‘Specialized Industrial Chemicals’ functional use class according to the EPA Safer Chemical guidelines.
Cosmetic Products Containing Ammonium Hydroxide
Recent products using Ammonium Hydroxide in their cosmetic formulations
- CVS 5 Minute Whitening Kit Tooth Whitening System
- OPI BondAid pH Balancing Agent
- OPI ChipSkip, For Natural Nails
- ReflectoCil Intense Browns Activator Gel
- SheaMoisture Enhancing Smoothie Coconut and Hibiscus
- Malin+Goetz Resurfacing Glycolic Pads
- NYX Professional Makeup That’s The Point Eyeliner, On The Dot
- Milani Stay Put Matte Eyeliner, Espresso
- Doucce Bold Control Graphic Marker
- Morphe Liquid Liner, Black Out
Top companies using Ammonium Hydroxide in their cosmetic products
- CVS
- OPI
- ReflectoCil
- SheaMoisture
- Malin+Goetz
- NYX Professional Makeup
- Milani
- Doucce
- Morphe
How Ammonium Hydroxide Works in Formulations
Ammonium Hydroxide is a strong base commonly used in cosmetic formulations to adjust pH, enhance cleansing, and aid in the dissolution of certain active ingredients.
Ideal Concentration and Benefits in Different Formulations
pH Adjuster and Buffering Agent
Ammonium Hydroxide is used to increase the pH of cosmetic products, helping other ingredients perform optimally in an alkaline environment.
- Concentration: 0.1%–2%
- Benefit: Activates ingredients that work best in an alkaline setting, ensuring they function effectively.
Cleansing Agent
Ammonium Hydroxide is sometimes used in cleaning formulations (e.g., facial cleansers) for its ability to break down oils and dirt on the skin. Its high pH can help remove impurities by breaking down surface grease, making it effective in certain formulations.
Compatibility with Other Ingredients
Ammonium Hydroxide is compatible with many surfactants, emulsifiers, and some active ingredients, though care should be taken when mixing it with acidic ingredients, which could lead to neutralization or undesirable reactions. It is particularly effective in formulations where an alkaline environment is needed to activate other components, such as in certain exfoliating or clarifying products.
Stability and Shelf Life
Ammonium Hydroxide may reduce the shelf life of some products due to its strong alkaline nature, which could destabilize other ingredients.
- Shelf life: 2 years when stored at room temperature
- Best storage: Keep in tightly sealed containers to prevent evaporation of ammonia, which could weaken its effectiveness over time
Formulation Challenges and Troubleshooting
Ammonium Hydroxide presents some formulation challenges due to its strong alkalinity, volatility, and potential for irritation. Here are some common issues and troubleshooting tips:
pH Sensitivity
Ammonium Hydroxide is a very strong base, and its high pH can destabilize some ingredients or lead to irritation if used in high concentrations.
Solution: Carefully monitor and adjust the pH to avoid exceeding the intended pH range (generally between 4.5–7 for most cosmetics). Use pH buffers like citric acid or sodium citrate to stabilize the formulation.
Irritation and Sensitivity
Ammonium Hydroxide can cause skin irritation, especially in products that are left on the skin, such as lotions or hair care products.
Solution: Use Ammonium Hydroxide in low concentrations (typically below 2%) for pH adjustment in rinse-off products. For leave-on products, consider using milder alternatives like sodium bicarbonate or citric acid.
Volatility and Odor
Ammonium Hydroxide has a strong ammonia odor, which can be off-putting in cosmetic formulations and may dissipate into the air during processing.
Solution: Formulate in well-ventilated areas and ensure airtight packaging to minimize exposure to ammonia vapors. Consider masking the odor with fragrance or essential oils if needed.
Interaction with Acids
When mixed with acidic ingredients, Ammonium Hydroxide can neutralize acids, potentially altering the formulation’s effectiveness or stability.
Solution: Avoid using Ammonium Hydroxide in combination with strong acids. If both are required in a formulation, carefully adjust the amounts to maintain product efficacy and stability.
Packaging Compatibility
Ammonium Hydroxide may interact with certain types of packaging, especially materials that are sensitive to alkaline compounds.
Solution: Use packaging made from materials that can withstand high pH levels, such as high-density polyethylene (HDPE) or glass. Avoid packaging in containers that may degrade due to the alkalinity.
Is Ammonium Hydroxide Safe in Cosmetics?
Safety reports for Ammonium Hydroxide are given below:
- Safety Assessment of Ammonia and Ammonium Hydroxide as Used in Cosmetics. Download PDF
Regulatory Considerations for Using Ammonium Hydroxide in Cosmetic Formulations
Few regulatory considerations are to be taken into account before using Ammonium Hydroxide as an ingredient. Given below is the list of those regulations:
FDA Requirements: Substance is affirmed as generally recognized as safe (GRAS) when added directly to food.
FIFRA Requirements: Exempted from tolerance requirements when used as a solvent, cosolvent, or neutralizer in pesticide formulations under good agricultural practices.
CERCLA Reportable Quantities: Releases exceeding 1000 lb (454 kg) must be reported to the National Response Center (NRC).
Clean Water Act Requirements: Designated as a hazardous substance under the Federal Water Pollution Control Act, regulated under the Clean Water Act Amendments.
New Zealand EPA Inventory of Chemical Status: Ammonium Hydroxide is approved for use under appropriate group standards without requiring individual approval.
Ammonium Hydroxide Side Effects
Ammonium Hydroxide is a corrosive chemical that can cause significant irritation or damage upon exposure. Direct contact with the skin or eyes may result in burns, while inhalation of its vapors can lead to respiratory distress. Ingestion poses risks of severe gastrointestinal damage.
Proper safety precautions, including the use of personal protective equipment and adequate ventilation, are crucial to minimizing its toxicological risks. Chronic exposure can lead to respiratory and mucous membrane irritation, emphasizing the importance of regulated usage and monitoring in both industrial and cosmetic applications.
Symptoms
- Eye Exposure: Can cause redness, pain, blurred vision, severe burns.
- Skin Exposure: Can cause redness, pain, blisters, serious burns.
- Ingestion Exposure: Calead to sore throat, vomiting, abdominal pain.
- Inhalation Exposure: Can cause cough, sore throat, burning sensation, shortness of breath.
Toxicity Data
The LCLo (Lowest Concentration Lethal) value for Ammonium Hydroxide is 5,000 ppm in humans, indicating its potential lethality at high airborne concentrations.
Adverse Effects
- Dermatotoxin: Can cause severe skin burns.
- Lacrimator: Irritates the eyes, causing excessive tearing.
- Toxic Pneumonitis: May induce lung inflammation upon inhalation.
Exposure Routes
Can be absorbed via inhalation or ingestion.
Medical Surveillance
Routine medical examinations, including lung function tests, chest X-rays, and evaluation of respiratory and skin health, are recommended for individuals exposed to Ammonium Hydroxide.
Non-Human Toxicity Values
Ammonium Hydroxide has an LD50 of 350 mg/kg (oral, rats), indicating moderate acute toxicity when ingested.
Antidote and Emergency Treatment
- Basic Treatment: Ensure clear airways and administer oxygen as needed. For eye exposure, flush with saline continuously. For ingestion, rinse the mouth and provide water for dilution. Do not induce vomiting or attempt neutralization.
- Advanced Treatment: Intubation may be required for airway obstruction. Monitor cardiac rhythm and treat as necessary. Administer fluids cautiously in cases of hypovolemia and watch for pulmonary edema.
Environmental and Sustainability Impact
Ammonium Hydroxide is used in cosmetics primarily as a pH adjuster, buffering agent, and cleansing agent. However, its environmental impact is an important consideration:
Environmental Impact
- Water Pollution: Ammonium Hydroxide, when released into water systems, can raise the pH and introduce ammonia, which can harm aquatic life and disrupt ecosystems. It can lead to the process of eutrophication, where excess nutrients cause algae blooms and oxygen depletion.
- Carbon Footprint: Ammonium Hydroxide is typically derived from ammonia, a chemical with a significant carbon footprint due to its industrial production, which is energy-intensive and often powered by fossil fuels.
Sustainability
The sustainability of Ammonium Hydroxide largely depends on its production and disposal methods.
- Raw Materials: It is produced from ammonia, a synthetic substance typically derived from fossil fuels. The sustainability of Ammonium Hydroxide could improve if renewable energy sources are used during its production.
- Energy Use: Production of ammonia, and hence Ammonium Hydroxide, is energy-intensive, particularly in the Haber-Bosch process. Sustainable production could be achieved by using green energy in the synthesis process.
- End-of-Life Impact: Once Ammonium Hydroxide is used in products, it may contribute to water pollution if improperly disposed of, as it can decompose into ammonia and CO₂, which affect aquatic life.
Biodegradability and Toxicity
Ammonium ions are naturally converted into nitrate (NO₃⁻) or nitrogen gas (N₂) through microbial processes (nitrification and denitrification), reducing long-term pollution risks.
- Toxicity: ree ammonia (NH₃) is toxic to fish and aquatic life, affecting respiration and leading to ammonia poisoning at high levels. However, in neutral or acidic waters, ammonium (NH₄⁺) is less toxic and gets converted into nitrogen compounds.
- Environmental Impact: If released in large quantities, Ammonium Hydroxide can lead to toxicity in aquatic systems, affecting fish, plants, and other organisms. Its impact depends on local environmental conditions.
Eco-Friendly Alternatives
Several alternatives to Ammonium Hydroxide offer lower environmental impact:
- Sodium Hydroxide: A common alternative to Ammonium Hydroxide, sodium hydroxide (lye) also serves as a strong base but is less toxic to aquatic life.
- Citric Acid: A biodegradable and eco-friendly acid used as a pH adjuster in cosmetic formulations. It is derived from renewable sources and has minimal environmental impact.
- Potassium Hydroxide: Another alternative to Ammonium Hydroxide, potassium hydroxide is often considered more environmentally benign, especially when derived from renewable sources.
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