Diethanolamine (DEA) is an important organic chemical raw material, which is widely used in the fields of medicine, pesticide, dyestuff, rubber, plastics, textile and so on. In the field of raw materials for chemical production, the main manufacturing methods of diethanolamine are chloroethanol method, ethylene oxide method and ammoniation method. This article will introduce these three manufacturing methods in detail.
1. Chloroethanol method
Chloroethanol method is to use chloroethanol and ammonia as raw materials, after neutralization, distillation, dehydration and other processes to produce diethanolamine. The specific steps are as follows:
(1) Add chloroethanol and liquid ammonia into the reactor, control a certain temperature and pressure, and carry out the neutralization reaction to produce chloramine and ethanol.
(2) The reaction solution was distilled to separate the unreacted chloroethanol and ammonia to obtain a mixture of chloramine and ethanol.
(3) The mixture of chloramine and ethanol is added to a dehydrating agent, and a certain temperature and pressure are controlled to carry out a dehydration reaction to produce diethanolamine and water.
(4) The water is separated out and the diethanolamine is refined to obtain the finished product.
Chloroethanol method has a mature production process and is simple to operate, but the production process generates a large amount of wastewater and exhaust gas, which is more polluting to the environment.
2. Ethylene oxide method
Ethylene oxide method takes ethylene oxide and ammonia as raw materials, and produces diethanolamine through addition, hydrolysis, distillation and other processes. The specific steps are as follows:
(1) Add ethylene oxide and liquid ammonia into the reactor and carry out addition reaction under certain temperature and pressure to produce aminoethanol.
(2) The reaction solution is hydrolyzed to convert aminoethanol into diethanolamine and water.
(3) The water is separated and the diethanolamine is distilled to obtain the finished product.
Ethylene oxide method production process is relatively simple, high purity of the product, but the production process requires high temperature and high pressure conditions, energy consumption.
3. Ammoniation method
Ammoniation method is to use glyoxal and ammonia as raw materials, after addition, reduction, distillation and other processes to produce diethanolamine. The specific steps are as follows:
(1) Add glyoxal and liquid ammonia into the reactor and carry out addition reaction under certain temperature and pressure to produce aminoacetaldehyde.
(2) Aminoacetaldehyde is subjected to a reduction reaction to produce diethanolamine.
(3) The diethanolamine is distilled to obtain the finished product.
The production process of the ammoniation method is relatively new and the product yield is high, but the production process requires the use of valuable catalysts and the cost is high.
In summary, chloroethanol method, ethylene oxide method and ammoniation method can be used to manufacture diethanolamine, but each method has its advantages and disadvantages and scope of application. In the actual production, the suitable manufacturing method can be selected according to the specific situation. Meanwhile, in order to protect the environment and reduce energy consumption, the manufacturing process of diethanolamine needs to be further improved and optimized.
