Diethylene glycol (DEG) is an important chemical raw material, widely used in solvents, lubricants, antifreeze, plasticizers and other fields. The following are the manufacturing methods of diethylene glycol, including chloroethanol method, ethylene oxide hydrate method, ethylene glycol method and so on.
I. Chloroethanol method
Chloroethanol method is the main method to produce diethylene glycol at home and abroad, and its process flow is as follows:
1. Chloroethanol reacts with aqueous sodium hydroxide to produce sodium chloroethanol.
2. Sodium chloroethanol reacts with sulfuric acid to produce diethylene glycol and sodium sulfate.
3. Diethylene glycol is separated from sodium sulfate to obtain a pure diethylene glycol product.
The advantage of this method is that the process is mature, simple operation, low cost, but the production process will produce a large amount of wastewater and exhaust gas, which is more polluting to the environment.
II. Ethylene oxide water method
Ethylene oxide water method is a more advanced method to produce diethylene glycol, its process flow is as follows:
1. Ethylene oxide reacts with water under the action of catalyst to produce ethylene glycol.
2. Ethylene glycol is dehydrated under the action of an acidic catalyst to produce diethylene glycol.
The advantage of this method is that the production process produces less wastewater and exhaust gas, and has less impact on the environment, but it requires the use of precious metal catalysts, and the cost is higher.
Third, ethylene glycol method
Ethylene glycol method is a more traditional method of producing diethylene glycol, its process flow is as follows:
1. ethylene glycol reacts with methanol under the action of acid catalyst to produce methyl ethylene glycol.
2. Methyl glycol is dehydrated to form diethylene glycol in the presence of an alkaline catalyst.
The advantage of this method is that the process is simple and easy to operate, but the production process requires the use of a large amount of methanol, which is costly and generates a certain amount of wastewater and exhaust gas.
In summary, the chloroethanol method, the ethylene oxide hydrate method and the ethylene glycol method are all methods for the production of diethylene glycol, and each method has its advantages and disadvantages and scope of application. When choosing the production method, you need to make comprehensive consideration according to the actual situation and choose the most suitable production method for you. Meanwhile, with the increasing awareness of environmental protection and the continuous progress of technology, the future production process of diethylene glycol will be more environmentally friendly, efficient and energy-saving.
