Geraniol (pentanediol) is a common raw material for the production of chemicals and is widely used in plastics, fibers, coatings, pharmaceuticals and other fields. Several methods of manufacturing geraniol will be described below.
1. Ethylene oxidation method
Ethylene oxidation method is a commonly used method for manufacturing perylene glycol. This method takes ethylene as raw material and generates ethylene glycol through oxidation reaction. The specific steps are as follows:
(1) Ethylene and oxygen are mixed and introduced into an oxidation reactor, where an oxidation reaction is carried out under the action of a silver catalyst to produce glyoxalic acid.
(2) React the glyoxalic acid with water to form ethylene glycol and formic acid.
(3) The glycol and formic acid are separated by distillation to obtain pure perylene glycol.
The advantages of this method are easy availability of raw materials, mild reaction conditions and high purity of the product. However, the method requires the use of a valuable silver catalyst and has a high production cost.
2. Dimethyl carbonate method
Dimethyl carbonate method is a relatively new method of manufacturing perylene glycol. This method takes dimethyl carbonate and hydrogen as raw materials, and generates perylene glycol by hydrogenation reaction. The specific steps are as follows:
(1) After mixing dimethyl carbonate and hydrogen, it is introduced into a hydrogenation reactor, and under the action of a copper-zinc catalyst, a hydrogenation reaction is carried out to generate perylene glycol and methanol.
(2) Separate the perylene glycol and methanol by distillation to obtain pure perylene glycol.
The advantages of this method are the easy availability of raw materials, mild reaction conditions, and low catalyst price. However, the method requires high pressure hydrogen and higher safety production requirements.
3. Chloroethanol method
Chloroethanol method is a traditional method for manufacturing perylene glycol. This method takes chloroethanol as raw material and generates perylene glycol by hydrolysis reaction. The specific steps are as follows:
(1) Mix chloroethanol with water, introduce it into the hydrolysis reactor, and under the action of acid catalyst, carry out the hydrolysis reaction to produce perylene glycol and hydrochloric acid.
(2) The hydrochloric acid is removed by neutralization treatment, and then the geraniol and water are separated by distillation to obtain pure geraniol.
The advantage of this method is that the process is simple and the investment in equipment is low. However, the method will produce a large amount of acidic wastewater, and environmental protection treatment is difficult.
In summary, the above three methods can be used in the manufacture of perylene glycol, but each has its own advantages and disadvantages. In the actual production, the suitable method should be selected according to the specific situation. At the same time, in order to reduce production costs and improve product quality, it is also necessary to continuously optimize the production process and equipment, and strengthen production management and quality control.
