Ammonium acetate
Ammonium Acetate, with the chemical formula CH₃COONH₄, is the salt resulting from the reaction between acetic acid and ammonia. It appears as a white crystalline solid, is hygroscopic (moisture-absorbing), and has a faint ammonia odor due to partial decomposition. This compound is derived from a weak acid (acetic acid) and a weak base (ammonia), which gives it buffering properties in aqueous solution.
Structure of Ammonium Acetate
Ammonium acetate is an ionic compound composed of the ammonium cation (NH₄⁺) and the acetate anion (CH₃COO⁻). The acetate ion exhibits resonance between its two oxygen atoms, which contributes to its relative stability.
Chemical formula: CH₃COONH₄
Properties of Ammonium Acetate
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Appearance: White crystalline powder, transparent or granulated
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Solubility: Highly soluble in water and ethanol; slightly soluble in acetone
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Hygroscopic: Easily absorbs moisture from the air
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Melting Point: ~114 °C; decomposes upon heating into acetic acid and ammonia
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Density: ~1.07 g/cm³ at 25 °C (equivalent to 1070 kg/m³ in SI units)
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pH (aqueous solution): Nearly neutral, typically between 6.5 and 7.5 depending on concentration
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Compressibility: Compressible
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Colorless: Its solutions are usually clear and colorless
Applications of Ammonium Acetate
Food Industry:
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Used as a food additive (E264)
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Functions as a buffer and preservative in certain food products
Laboratory and Research:
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pH buffer: Used in biochemistry, analytical chemistry, and molecular biology to maintain stable pH in reactions and enzyme processes (e.g., DNA extraction and protein purification)
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Chromatography: Serves as a buffer or mobile phase in HPLC and mass spectrometry due to its volatility
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Microbial detection
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Biological media: Occasionally used in specialized bacterial growth environments
Pharmaceutical Industry:
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Used in the manufacture of certain drugs and injectable solutions
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Applied in organic synthesis of pharmaceutical compounds
Textile Industry:
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Functions as an auxiliary agent in textile printing and dyeing processes
Chemical Industry:
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Serves as a source of acetate or ammonia ions in organic synthesis
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Used in the production of certain plastics and resins
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Acts as a corrosion inhibitor in specific processes
Wastewater Treatment:
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Used in biological processes to supply carbon and nitrogen for bacteria
Environmental Applications:
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Used in some airport de-icing compounds as a chloride-free alternative
Advantages of Ammonium Acetate
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Strong buffering capacity: Regulates and maintains pH near neutral
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Volatile: Leaves no residue after evaporation, ideal for HPLC and mass spectrometry
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Biodegradable: Breaks down naturally in the environment
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High water solubility: Allows for preparation of high-concentration aqueous solutions
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Relatively safe: Low toxicity in lab and industrial settings
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Versatile use: Broadly applied across food, pharmaceutical, and chemical industries
Disadvantages of Ammonium Acetate
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Ammonia odor: Releases a pungent, mild ammonia smell upon decomposition
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Hygroscopicity: Absorbs moisture rapidly, requiring moisture-resistant packaging
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Thermal decomposition: Breaks down into ammonia and acetic acid at high temperatures
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Potential irritation:
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Eye contact: May cause irritation, redness, or burning
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Skin contact: May cause mild irritation
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Inhalation of dust: May cause coughing or shortness of breath
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Ingestion: In large amounts, may lead to gastrointestinal discomfort
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Ventilation required: Especially in enclosed areas, due to irritating vapors
Applications
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Ammonium acetate
Chemical name (IUPAC) | Molecular formula | Molecular mass | Physical appearance | Density (at 20°C) | Melting point | Solubility in water (20°C) | pH of 5% solution in water | Main applications |
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Ammonium ethanoate | CH₃COONH₄ | 77.08 g/mol | White, crystalline or granular powder | 1.17 g/cm³ | 114–116°C (decomposes at higher temperatures) | Completely soluble (~1480 g/L) | About 7.0 (neutral to slightly acidic) | Buffer in chromatography and biology, chemical synthesis, pharmaceutical additive, agriculture |