[Chemical Knowledge]：Manufacturing method and process of acrylic acid

The manufacturing method
of acrylic acid
1. Introduction

Acrylic acid is an important organic chemical raw material, widely used in coatings, plastics, fibers, rubber and other fields. With the continuous expansion of the application field of acrylic acid, its manufacturing method has become a research hotspot. This article will introduce the manufacturing methods of acrylic acid, including propylene oxidation, oxo synthesis, ethylene carbonylation, etc.

2. propylene oxidation

propylene oxidation is the main production method of acrylic acid, accounting for more than 80% of the total output of acrylic acid in the world. The method is to introduce propylene, air (or oxygen) and catalyst into the reactor, and carry out oxidation reaction at high temperature and pressure to produce acrylic acid and by-products.

1. reaction principle

propylene oxidation reaction principle is propylene and oxygen in the catalyst under the action of oxidation reaction to generate acrylic acid and by-products. The reaction equation is as follows:

CH2 = CH-CH3 +1/2 O2 → CH2 = CH-COOH + H2O

2. Process flow

The process flow of propylene oxidation method mainly includes the steps of raw material pretreatment, oxidation reaction, product separation and purification. The specific process is as follows:

(1) Raw material pretreatment: Propylene, air (or oxygen) and catalyst are added into the reactor respectively.

(2) Oxidation reaction: Under high temperature and pressure, propylene and oxygen are oxidized under the action of a catalyst to produce acrylic acid and by-products.

(3) Product Separation: Acrylic acid is separated from by-products by cooling, distillation, etc.

(4) Refining: Refining acrylic acid to obtain a product with high purity.

3. Advantages and Disadvantages
The advantages of the
propylene oxidation method are that the raw materials are readily available, the process is mature, the operation is simple, and the product purity is high. However, the disadvantages of this method are high energy consumption, easy deactivation of the catalyst, need to be replaced regularly, and high production cost.

3. carbonyl synthesis

carbonyl synthesis method is a more traditional acrylic acid manufacturing method, the method is propylene, carbon monoxide and hydrogen in the role of catalyst, the carbonylation reaction to produce acrylic acid.

1. reaction principle of

oxo synthesis reaction principle is propylene and carbon monoxide and hydrogen in the catalyst under the action of the carbonylation reaction to produce acrylic acid. The reaction equation is as follows:

CH2 = CH-CH3 + CO + H2 → CH2 = CH-COOH

2. Process flow
The process flow of
carbonyl synthesis mainly includes the steps of raw material pretreatment, carbonylation reaction, product separation and purification. The specific process is as follows:

(1) Raw material pretreatment: Propylene, carbon monoxide and hydrogen are added into the reactor respectively.

(2) carbonylation reaction: under the action of catalyst, propylene and carbon monoxide and hydrogen carbonylation reaction, acrylic acid.

(3) Product Separation: Acrylic acid is separated from unreacted raw materials and by-products by distillation or the like.

(4) Refining: Refining acrylic acid to obtain a product with high purity.

3. Advantages and Disadvantages
The advantages of
carbonyl synthesis are that the raw materials are easily available, the catalyst activity is high, and the reaction conditions are mild. However, the disadvantage of this method is that there are many by-products, many subsequent processing steps are required, and the production cost is high.

4. Ethylene carbonylation

Ethylene carbonylation is a new method for the production of acrylic acid, which is a carbonylation reaction of ethylene, carbon monoxide and water vapor under the action of a catalyst to produce acrylic acid.

1. reaction principle

ethylene carbonylation reaction principle is the ethylene and carbon monoxide and water vapor in the catalyst under the action of the carbonylation reaction to produce acrylic acid. The reaction equation is as follows:

CH2 = CH2 + CO + H2O → CH2 = CH-COOH

2. Process Flow

The process flow of ethylene carbonylation method mainly includes the steps of raw material pretreatment, carbonylation reaction, product separation and purification. The specific process is as follows:

(1) Raw material pretreatment: Ethylene, carbon monoxide and steam are added into the reactor respectively.

(2) carbonylation reaction: under the action of the catalyst, ethylene and carbon monoxide and water vapor carbonylation reaction, the formation of acrylic acid.

(3) Product separation: Acrylic acid is separated from unreacted raw materials and by-products by cooling, distillation, or the like.

(4) Refining: Refining acrylic acid to obtain a product with high purity.

3. Advantages and Disadvantages
The advantages of
ethylene carbonylation method are easy to obtain raw materials, mild reaction conditions, high catalyst activity and less by-products. However, the disadvantage of this method is that the catalyst cost is relatively high, it needs to be replaced regularly, and the production cost is relatively high.

5. Conclusion The main manufacturing methods of

acrylic acid include propylene oxidation, oxo synthesis and ethylene carbonylation. Different manufacturing methods have different advantages and disadvantages and scope of application. Enterprises can choose the appropriate manufacturing method according to their actual situation and needs. In the future, with the continuous advancement of technology and the expansion of application fields, the manufacturing method of acrylic acid will continue to be improved and optimized.