Isopropylamine (CAS 75-31-0): Chemical Properties, Key Applications, and Safe Handling

Isopropylamine (CAS 75-31-0) is a versatile and important primary amine with a wide range of industrial applications. This colorless liquid is characterized by its strong, ammonia-like odor and is a key building block in the synthesis of many chemical products.

Physical and Chemical Properties

Isopropylamine, with the chemical formula(CH₃)₂CHNH₂, as a molecular weight of 59.11.  It is a volatile liquid with a boiling point of 33°C and a melting point of -102°C. Its density is 0.688 g/cm³.

One of its key properties is its miscibility with water, ethanol, and ether.  It also dissolves readily in acetone, aromatic and aliphatic hydrocarbons, mineral oils, and paraffin wax.  When heated, isopropylamine can even dissolve solid paraffin wax and carnauba wax.  Its aqueous solutions are alkaline. A notable characteristic is its ability to form a binary azeotropic mixture, a mixture with a constant boiling point, with both water and isopropyl alcohol.

Purification Methods

Commercial isopropylamine is often synthesized by reacting bromo-isopropane with an alcohol solution of ammonia, or by reacting acetone with ammonia and hydrogen over a nickel-copper-clay catalyst. These processes can leave impurities such as acetone, bromo-isopropane, isopropyl alcohol, and various other propylamine compounds.

The primary method for purifying isopropylamine is distillation. For obtaining a very high purity product, a multi-step process is employed. First, anhydrous barium oxide is added to the impure solution and left for several days to remove water. Following this drying step, the isopropylamine is distilled in the presence of sodium. A very pure fraction can be collected at 31.4°C under a pressure of 0.99 x 133.3 Pa, which may then undergo further distillation.

Main Uses of Isopropylamine

Isopropylamine is a crucial intermediate in various industrial sectors.

• Pharmaceuticals and Pesticides: It serves as a precursor in the manufacturing of numerous pharmaceuticals and pesticides.

• Surfactants and Detergents: Due to its excellent foaming properties, foam stability, and ability to dissolve oils, it is used as an industrial synthetic detergent. It can be used as a raw material for other surfactants and as a refining agent, anti-static agent, dyeing aid, and fiber wetting agent in the textile industry because of its hygroscopicity and weak alkalinity.

• Coatings and Emulsifiers: It is used in the production of water-based coatings. Its reaction with fatty acids produces fatty acid isopropylamides, which have various applications. Isopropanolamine mixtures have exceptional solubility for hydrocarbons, and when combined with oleic acid in water, they can create stable emulsions with substances like kerosene and naphtha. The salts formed with long-chain fatty acids are effective emulsifiers for vinyl acetate resins, providing good emulsion and color stability.

• Cosmetics: When neutralized with thioglycolic acid, it forms a product that can be used as a base material for cosmetics.

• Lubricants and Other Applications: Its phosphates and nitrites act as antioxidants in various lubricants and cutting oils. Reaction products with different acids and higher fatty ketones can be used as plasticizers, emulsifiers, and solvents.
  

Safety and Handling Precautions

Isopropylamine is a Class 1 flammable liquid.  Its vapor can form a highly explosive mixture with air. Therefore, it must be stored in a sealed container in a cool, shaded, and well-ventilated area away from heat sources and open flames.

It is also a hazardous substance that can cause significant irritation to the eyes, skin, and mucous membranes.  Exposure can lead to health issues such as conjunctivitis, rhinitis, bronchitis, and dermatitis.  To protect workers, the maximum allowable concentration in the workplace is set at 5 parts per million (ppm). Proper personal protective equipment, including gloves, goggles, and respiratory protection, should be used when handling this chemical.