2-Methyl-2-propanol, but it is more widely known by the name tert-butanol.
1. Basic Information
· Chinese name: tert-Butyl alcohol; 2-methyl-2-propanol; trimethylmethanol; tert-dimethyl alcohol
· English name: tert-Butyl alcohol; 2-Methylpropan-2-ol; 2-Methyl-2-propanol; TBA
· CAS Number: 7364-28-5
· Molecular Formula: C₄H₁₀O
· Molecular Structure: (CH₃)₃COH
· Molecular Weight: 74.12 g/mol
2. Chemical Structure and Properties
Tert-butanol is one of the four isomers of butanol (the other three are normal butanol, secondary butanol and tertiary butanol). Its structural feature is that the carbon atom to which the hydroxyl group (-OH) is attached (the central carbon atom) is simultaneously connected to three methyl groups (-CH₃). This central carbon atom is a tertiary carbon atom, hence it is called "tert-butanol".
The properties resulting from the structural characteristics:
· Strong steric hindrance: The three methyl groups surround the hydroxyl group, making it difficult for other reagents to approach the hydroxyl group. Therefore, its chemical reactivity differs significantly from primary alcohols and secondary alcohols.
· Solid form: The melting point of tert-butanol is 25°C. Thus, it is a colorless crystalline solid at room temperature (slightly below 25°C), and a colorless transparent liquid at room temperature or higher temperatures. This is one of its very unique physical properties.
3. Physical and Chemical Properties
· Appearance: Colorless crystals or liquid, with a scent similar to camphor.
· Melting point: 25-26 °C
· Boiling point: 82.2-82.4 °C
· Density: 0.775-0.786 g/cm³ (at 20 °C)
· Flash point: 11 °C (closed cup) - classified as a flammable liquid.
· Solubility:
· Can be miscible with various organic solvents such as water, ethanol, ether, acetone, etc. in any proportion.
· Has a relatively high solubility in water because its molecules are small and highly polar. However, it is also often used as a precipitant in biochemical experiments for precipitating proteins and DNA.
4. Main Uses
Tert-butanol is an important chemical raw material and an excellent solvent, with wide applications:
1. Solvents and Extractants:
· Used as solvents for paints, resins, nitrocellulose, etc.
· Used as reaction solvents in pharmaceutical and pesticide synthesis.
· Used as raw materials for gasoline additives (MTBE, methyl tert-butyl ether) production, although the use of MTBE has decreased due to environmental issues.
2. Organic Synthesis Intermediate:
· Due to its large tert-butyl steric hindrance, it is often used as a protecting group. For example, it is used to protect carboxylic acids (to form tert-butyl esters) or alcohols (to form tert-butyl ethers) during synthesis, and can be conveniently removed with acid after the reaction.
· Used for synthesizing tert-butyl peroxides, fragrances, stabilizers, etc.
3. Industrial and Laboratory Applications:
· Gasoline Additives: As a component for increasing octane number.
· Denaturants: Added to industrial ethanol to make it undrinkable.
· Precipitants: In biochemistry, used to precipitate large molecules such as proteins and nucleic acids from aqueous solutions.
4. Other Uses:
· Manufacturing artificial musk.
· As a solvent in certain cosmetics and personal care products.
5. Safety and Risk
· Flammability: Its vapor can form an explosive mixture with air. It is highly prone to combustion and explosion upon contact with open flames or high heat. Storage and use should be kept away from fire sources.
· Health hazards:
· Inhalation: It has a stimulating effect on the eyes, nose, throat and respiratory tract, and may cause headache, dizziness and central nervous system depression.
· Ingestion: Toxic. It may cause abdominal pain, nausea, vomiting, dizziness, drowsiness, and in severe cases, loss of consciousness.
· Skin contact: It may cause dryness and irritation of the skin.
· Eye contact: Its vapor or liquid has a stimulating effect on the eyes.
· Environmental hazards: It may be harmful to aquatic organisms.
Safety operation precautions: The operation should be carried out in a well-ventilated area (such as a fume hood), and appropriate personal protective equipment (such as safety glasses and gloves) should be worn. Store in a cool and ventilated place, away from heat sources and oxidants.
Summary
CAS 7364-28-5 (tert-butanol) is a unique-structured and widely-used important organic compound. It is not only a common industrial solvent and chemical raw material, but also plays a crucial role as a protecting group and intermediate in organic synthesis. At the same time, it is also a commonly used precipitant in biochemistry laboratories. Due to its flammability and certain toxicity, strict safety operation procedures must be followed when using it.
