Trimethylolpropane (TMP) is an important raw material for the production of chemicals, widely used in coatings, resins, plastics, oil additives and other fields. Its manufacturing methods mainly include catalytic hydrogenation, formaldehyde condensation and glyoxalic acid. This article will introduce these three manufacturing methods in detail, and discuss their advantages and disadvantages and scope of application.
I. Catalytic Hydrogenation Method
The catalytic hydrogenation method takes propanetriol as the raw material and generates trimethylolpropane by addition reaction with hydrogen under the action of catalyst. This method has mild reaction conditions, easy operation and high product purity. However, the catalyst is costly, needs to be replaced periodically, and generates certain waste water and exhaust gas.
1. Process principle
Propanetriol, under the action of catalyst, reacts with hydrogen in an addition reaction to produce trimethylolpropane. The reaction equation is as follows:
CH2OH-CHOH-CH2OH + H2 → CH2(OH)CH2(OH)CH2OH
2. Process Flow
Propanetriol and catalyst are added into the reaction kettle, and hydrogen is passed in to control the reaction temperature and pressure, and the reaction generates trimethylolpropane. After the reaction, the product with high purity is obtained through filtration and distillation.
II. Formaldehyde condensation method
Formaldehyde condensation method is based on formaldehyde and propanetriol as raw materials, through the action of acid catalyst, condensation reaction occurs to generate trimethylolpropane. The raw material is easy to obtain and the cost is low, but the operation is more complicated and the purity of the product is low.
1. Process principle
Under the action of acid catalyst, formaldehyde and propanetriol undergo condensation reaction to produce trimethylolpropane. The reaction equation is as follows:
3CH2OH-CHOH-CH2OH + 3HCHO → CH2(OH)CH2(OH)CH2OH + 3H2O
2. Process flow
Propanetriol, formaldehyde and acid catalyst are added into the reaction kettle, and the reaction temperature and pH are controlled to generate trimethylolpropane. After the reaction, the product is obtained by filtration, neutralization and distillation.
Third, Glyoxalic acid method
Glyoxalic acid method is based on glyoxalic acid, formaldehyde and hydrogen as raw materials, through the action of catalyst, the addition and condensation reaction occurs to generate trimethylolpropane. The raw materials of this method are easier to obtain and the reaction conditions are mild, but the cost of catalyst is higher.
1. Process principle
Under the action of catalyst, glyoxalic acid reacts with formaldehyde in an addition reaction to produce intermediate products, and then reacts with hydrogen in an addition reaction to finally produce trimethylolpropane. The reaction equation is as follows:
CH3COCHO + HCHO → CH3C(OH)(CHO)CH2OH
CH3C(OH)(CHO)CH2OH + H2 → CH2(OH)CH2(OH)CH2OH
2. Technological process
Glyoxylic acid, formaldehyde and catalyst are added to the reactor, hydrogen is passed through the reactor, and the temperature and pressure of the reaction are controlled. Generate trimethylolpropane. After the reaction, the product with high purity is obtained by filtration and distillation. In summary, the three manufacturing methods have their own advantages and disadvantages as well as scope of application. Catalytic hydrogenation method has high product purity and is suitable for the field with high requirements on product quality; formaldehyde condensation method has lower cost and is suitable for large-scale production; glyoxalate method has more readily available raw materials and mild reaction conditions, and is suitable for production in specific occasions. In actual production, the appropriate manufacturing method can be selected according to specific needs and conditions.
