Morpholine is an organic chemical compound with the chemical formula O(CH2CH2)2NH. This heterocycle contains both amine and ether functional groups. Because of the amine, morpholine is a base; its conjugate acid is called morpholinium. For example, treating morpholine with hydrochloric acid makes the salt morpholinium chloride. The naming of morpholine is attributed to Ludwig Knorr, who incorrectly believed it was part of the structure of morphine. Morpholine appears as a colorless liquid with a fish-like odor.

The chemical and physical properties of morpholine are as follows:

• Its molecular weight is 87.122 g/mol.
• Melting point is -5 °C.
• Its boiling point is 129 °C.
• Its density is 1.007 g/cm3.
• Solubility is high in water and alcohol, low in ether.

The production methods of morpholine are as follows:

• Reductive ammoniation method with hydrogen: This is the most common production method of morpholine. It can be prepared by hydrogen reducing ammoniation of diethylene glycol. Water is also produced in this method.
• Sulfuric acid method: This method is an alternative production method of morpholine. Diethanol amine can be prepared by dehydrogenation of a strong acid. This method also yields water and ethanol.
• Bis (chloroethyl) ether method: This is an old method of production of morpholine. It can be prepared by heating bis (chloroethyl) ether in excess of ammonia. This method also yields hydrochloric acid and ethylene glycol.

Uses of morpholine include the following:

• Water treatment: Morpholine is used as an intermediate in corrosion inhibitors to protect metals against corrosion and dulling (darkening) by acid vapors in steam boiler water treatment systems and aqueous hydraulic fluids.
• Detergent Morpholine is used as an additive in optical brighteners that are stable to chlorine bleaching, for use in detergents.
• Cosmetics: Morpholine is used in fatty acid salts for water-resistant emulsifier and plasticizer formulations in cosmetics. It is also used as an intermediate in quaternary morpholinium salts for hair conditioners and deodorant products.
• Pharmaceuticals: Morpholine is used as an intermediate in the production of medicines (analgesics, local anesthetics, antibiotics, antimycotics and antiplaque products).
• Photography Morpholine also plays an important role in the photography industry. Morpholine is used in the production and development of photographic films.