According to these physical properties of morpholine, morpholine and its derivatives can be used as effective corrosion inhibitors for metals such as steel, iron, copper, zinc, aluminum, etc. More than 5 000 tons of morpholine is consumed every year in the world. At present, China's research and development and application in this field are just in the initial stage. Below, according to the physical characteristics of morpholine, N- methylmorpholine manufacturers will introduce the main applications of morpholine!
The application of morpholine as metal corrosion inhibitor mainly includes the following aspects:
(1) used as metal gas antirust agent
Morpholine is widely used as metal gas antirust agent abroad to prevent metal from being corroded by the atmosphere, and has been widely used in mechanical instruments, automobiles, medical devices and other fields. The metal atmospheric antirust agents dicyclohexylamine nitrite and cyclohexylamine carbonate used at home and abroad have great toxicity to human body and environment, which restricts the popularization and application of vapor-phase antirust agents. Morpholine, as a metal gas-liquid corrosion inhibitor, has the advantage of low toxicity and good development prospect.
(2) for boiler and water circulation system
Morpholine has similar properties to secondary amine, is weakly alkaline, can neutralize carbonic acid in acidic aqueous solution, and is widely used as corrosion inhibitor for boilers and other water circulation systems. Morpholine remains stable in any state in medium and high pressure systems. The vapor pressure of morpholine is similar to that of water, and it can be dissolved in water at will, so it can keep a constant p H value in the system. Morpholine is often used in combination with other amines to solve special corrosion problems.
(3) as an anti-corrosion additive
In lubricating oil, paint, metal cleaner, paint remover and 1, 1, 1- trichloroethane, a certain amount of morpholine or morpholine derivative is often added as corrosion inhibitor, such as N, N-polythiodimorpholine, N, N-cycloalkyl dimorpholine and poly (4- morpholinmethyl) phenol, etc., which are added to lubricating oil in contact with water, can effectively prevent the corrosion of operating equipment parts. At the same time, it is also used as antioxidant additive for lubricating oil.
N-tert-butylthiomorpholine or petroleum sulfonate morpholine can be added as corrosion inhibitor in oil storage tanks, pipelines and distillation equipment, which can effectively prevent corrosion. The application of morpholine in China is almost blank because of its low yield and high valence. In the future, with the increase of morpholine production and the decrease of market price, the application of morpholine in anticorrosion will increase.