Acetaldehyde is a volatile organic compound produced during alcohol metabolism, causing hangover symptoms. It’s also used as a chemical intermediate in various industries.
| IUPAC Name | Ethanal |
| Molecular Formula | C₂H₄O |
| CAS Number | 75-07-0 |
| Synonyms | Ethyl aldehyde, Acetic aldehyde, Ethanal, 1-oxapropylene |
| InChI | InChI=1S/C2H4O/c1-2-3/h2H,1H3 |
Acetaldehyde Properties
Acetaldehyde Formula
The formula of ethanal is C₂H₄O. It consists of two carbon atoms, four hydrogen atoms, and one oxygen atom. The formula represents the ratio of atoms present in a molecule of ethanal.
Acetaldehyde Molar Mass
The molar mass of ethanal is approximately 44.05 g/mol. It is calculated by summing the atomic masses of all the atoms in the molecule according to the formula C₂H₄O.
Acetaldehyde Boiling Point
Ethanal has a boiling point of approximately 20.2 degrees Celsius (68.4 degrees Fahrenheit). This is the temperature at which ethanal changes from a liquid to a gas state under standard atmospheric pressure.
Acetaldehyde Melting Point
The melting point of ethanal is approximately -123.5 degrees Celsius (-190.3 degrees Fahrenheit). This is the temperature at which ethanal changes from a solid to a liquid state.
Acetaldehyde Density g/mL
The density of ethanal is about 0.78 g/mL. This value represents the mass of ethanal per unit volume. It indicates how closely packed the molecules are in a given volume of the substance.
Acetaldehyde Molecular Weight
The molecular weight of ethanal is approximately 44.05 g/mol. It is the sum of the atomic weights of all the atoms in the molecule and is expressed in grams per mole.
Acetaldehyde Structure
Ethanal has a linear structure, with the carbon atoms bonded to each other and to the oxygen atom. The molecule has a central carbon atom, two hydrogen atoms attached to it, and an oxygen atom bonded to the carbon atom.
Acetaldehyde Solubility
Ethanal is soluble in both water and organic solvents. It readily dissolves in water due to the presence of polar functional groups. The solubility of ethanal in water decreases with increasing temperature.
| Appearance | Colorless liquid |
| Specific Gravity | 0.780 g/mL |
| Color | Colorless |
| Odor | Pungent, fruity |
| Molar Mass | 44.05 g/mol |
| Density | 0.78 g/mL |
| Melting Point | -123.5 °C |
| Boiling Point | 20.2 °C |
| Flash Point | -36 °C |
| Water Solubility | Miscible |
| Solubility | Soluble in organic solvents such as ether, alcohol, acetic acid |
| Vapor Pressure | 97.2 mmHg at 25 °C |
| Vapor Density | 1.52 (air = 1) |
| pKa | 13.55 |
| pH | 3.5-4.5 |
Acetaldehyde Safety and Hazards
Ethanal poses several safety and hazard concerns. It is highly flammable, so precautions must be taken to prevent ignition sources. Inhalation of ethanal vapor can irritate the respiratory system, eyes, and skin. Prolonged exposure may lead to more severe health effects. Ethanal is also a potential carcinogen, associated with an increased risk of cancer. Proper ventilation and personal protective equipment should be used when handling ethanal. Additionally, it is important to store and handle ethanal in a well-ventilated area away from incompatible substances. Following safety guidelines and protocols is crucial to minimize the risks associated with ethanal.
| Hazard Symbols | Flammable, Harmful, Carcinogenic |
| Safety Description | Keep away from heat, sparks, and open flame. Avoid inhalation and contact with eyes and skin. Use proper ventilation and personal protective equipment. Store in a cool, well-ventilated area away from incompatible substances. Follow safety guidelines and protocols. |
| UN IDs | UN1089 |
| HS Code | 29121900 |
| Hazard Class | 3 (Flammable Liquids) |
| Packing Group | II |
| Toxicity | Acute toxicity: harmful if swallowed, inhaled or absorbed through the skin. Long-term exposure may increase the risk of cancer. |
Acetaldehyde Synthesis Methods
There are several methods to synthesize ethanal. One common approach involves oxidizing ethanol using oxidizing agents like potassium dichromate or copper oxide under acidic conditions. This reaction produces ethanal as the primary product.
Another method entails dehydrogenating ethylene by passing it over a catalyst such as silver or copper at high temperatures. This process removes hydrogen atoms from ethylene, resulting in the formation of ethanal.
In the hydration of acetylene, one can obtain ethanal. When acetylene gas reacts with water in the presence of catalysts like mercuric sulfate or phosphoric acid, it yields ethanal.
Suitable oxidizing agents like nitric acid or potassium permanganate can be used to produce ethanal by oxidizing ethylene glycol. This oxidation converts ethylene glycol into ethanal.
These examples illustrate various synthesis methods for ethanal, each with its own advantages. The choice of method may depend on factors such as the availability of starting materials, desired yield, and reaction conditions.
Acetaldehyde Uses
Ethanal has various uses across different industries. Here are some of its key applications:
- Chemical Intermediate: Ethanal serves as an important chemical intermediate in the production of many organic compounds, including acetic acid, pyridine, and pentaerythritol.
- Food and Beverage Industry: In the food and beverage industry, ethanal serves as a flavoring agent and preservative. Ethanal imparts fruity or nutty flavors to various products, such as fruit juices, candies, and baked goods.
- Plastic and Resin Production: Manufacturers utilize ethanal to produce plastics and resins, including polyvinyl acetate (PVA) and polyacetal.
These materials find applications in adhesives, coatings, and synthetic fibers. - Pharmaceuticals: Ethanal is a precursor in the synthesis of many pharmaceutical compounds. Ethanal plays a role in manufacturing vitamins, antimalarial drugs, and sedatives.
- Rubber Industry: The production of synthetic rubber involves the use of ethanal. It aids in the crosslinking of rubber polymers, enhancing their durability and elasticity.
- Textile Industry: Ethanal finds application as a dyeing and finishing agent in the textile industry. It helps improve the color fastness and overall quality of the textile materials.
- Fuel and Energy: Ethanal is a potential biofuel candidate due to its high energy content. Ethanal actively ferments to convert into ethanol or actively serves as a fuel additive.
These are just a few examples of the versatile uses of ethanal. Its diverse properties make it a valuable component in various industrial processes, contributing to the development of a wide range of products across multiple sectors.
Questions:
Q: How to remove acetaldehyde from the body?
A: Ethanal is naturally broken down by enzymes in the liver, but maintaining a healthy lifestyle, including proper hydration and a balanced diet, can support the body’s detoxification processes.
Q: What is acetaldehyde?
A: Ethanal is a volatile organic compound that is naturally produced in the body during alcohol metabolism and also found in various industrial processes and food products.
Q: What atomic or hybrid orbitals make up the bond between C2 and O in acetaldehyde, CH3CHO?
A: The bond between C2 and O in acetaldehyde is formed by the overlap of the sp² hybrid orbital of carbon and the sp² hybrid orbital of oxygen.
Q: How does acetaldehyde affect the liver?
A: Ethanal can cause liver damage by interfering with its normal functions, leading to inflammation, oxidative stress, and the accumulation of fat in the liver.
Q: What does acetaldehyde smell like?
A: Ethanal has a pungent and fruity odor, often described as being similar to fresh-cut apples or nail polish remover.
Q: Is acetaldehyde soluble in water?
A: Yes, ethanal is soluble in water. It readily dissolves due to the presence of polar functional groups.
Q: Should I avoid eating foods with acetaldehyde?
A: Ethanal is naturally present in many foods, including fruits, vegetables, and fermented products. Moderate consumption of these foods is generally safe for most individuals.
Q: What is acetaldehyde found in?
A: Ethanal can be found in alcoholic beverages, fruits, vegetables, coffee, bread, and various fermented food products.
Q: What does acetaldehyde taste like?
A: Ethanal has a sharp, bitter taste.
Q: How to store acetaldehyde?
A: Ethanal should be stored in a cool, well-ventilated area away from ignition sources, incompatible substances, and direct sunlight. It is typically stored in sealed containers.
Q: How does acetaldehyde affect the body?
A: Ethanal can have toxic effects on the body, causing symptoms like headache, nausea, and flushing, especially when produced in large amounts during alcohol metabolism.
Q: What is acetaldehyde used for?
A: Ethanal is used as a chemical intermediate in various industries, including food and beverage, pharmaceuticals, plastics, and textiles.
Q: How to pronounce acetaldehyde?
A: Uh-see-tuhl-deh-hahyd.