What is the process route for the production of acetic acid by acetaldehyde oxidation?

In the modern chemical industry, acetaldehyde oxidation is one of the main process routes for the production of acetic acid. The method uses acetaldehyde as raw material to generate acetic acid under specific oxidation conditions, which has the advantages of mature process and simple technology. What is the specific process route for the production of acetic acid by acetaldehyde oxidation? This article will discuss in detail from three aspects: process overview, detailed process and analysis of advantages and disadvantages.

Process Overview

the production of acetic acid by acetaldehyde oxidation is a classic chemical process, the core of which is the oxidation of acetaldehyde (CH3CHO) to acetic acid (CH3COOH). This process was first developed in the early 20th century and gradually applied to industrial production. Compared with the traditional fermentation method, acetaldehyde oxidation method has higher efficiency and lower production cost, so it is widely used.

In the process design, acetaldehyde oxidation method usually adopts liquid or gas phase oxidation system, and uses suitable catalyst to improve the reaction efficiency. The conditions of oxidation reaction include temperature, pressure and the choice of catalyst, which have an important influence on the conversion and selectivity of the reaction.

Detailed process flow of process route

the process route for the production of acetic acid by acetaldehyde oxidation can be divided into the following main steps:

1. Preparation of raw materials

acetaldehyde is the core raw material of the process, usually refined acetaldehyde as raw material. In the production process, acetaldehyde needs to undergo strict purification treatment to remove impurities and moisture to ensure the smooth progress of the reaction.

2. Oxidation reaction

the oxidation reaction of acetaldehyde is the key step of the whole process. In the presence of a catalyst, acetaldehyde reacts with an oxidizing agent, such as oxygen or hydrogen peroxide, to produce acetic acid. The basic chemical equation of the reaction is as follows:

[2 \, CH3CHO O2 \rightarrow 2 \, CH_3COOH]

in order to increase the efficiency of the reaction, it is generally necessary to control the temperature and pressure of the reaction. The reaction temperature is generally controlled between 50°C and 100°C, and the reaction pressure is adjusted depending on the oxidation system.

3. Selection of catalyst

the catalyst plays a vital role in the acetaldehyde oxidation reaction. Commonly used catalysts include manganese dioxide (MnO2), metal oxides such as copper oxide, and supported catalysts such as activated carbon supported copper oxide. These catalysts can significantly increase the reaction rate while reducing the occurrence of side reactions.

4. Reaction post-treatment

after the oxidation reaction is completed, the resulting mixture needs to be separated and purified. The acetic acid is separated from unreacted acetaldehyde, water and by-products by distillation or rectification. Subsequently, it is further refined to remove impurities, and a high purity acetic acid product is obtained.

5. Waste gas and waste liquid treatment

during the oxidation reaction, a certain amount of waste gas and waste liquid may be produced. In order to meet environmental requirements, these by-products need to be purified and recycled by professional treatment equipment to reduce the impact on the environment.

Analysis of the advantages and disadvantages of the process route

advantages

1. simple process and low cost: The process of acetaldehyde oxidation is relatively simple, the equipment investment is small, and the operating cost is low.
2. high selectivity: Under suitable catalyst and reaction conditions, the oxidation reaction of acetaldehyde has higher selectivity and fewer side reactions.
3. Rich source of raw materials: Acetaldehyde can be obtained through various channels, such as ethanol oxidation, ethylene oxidation, etc., and the supply of raw materials is sufficient.

Disadvantages

1. low single-pass conversion of the oxidation reaction: Due to the low equilibrium conversion rate of acetaldehyde in the oxidation reaction, it usually requires multiple cycles or increased reaction time.
2. easy deactivation of catalyst: Part of the catalyst is easily deactivated during the reaction process, resulting in a decrease in reaction efficiency and increasing the replacement cost of the catalyst.
3. High environmental requirements: Some pollutants may be produced during the oxidation reaction, which requires additional environmentally friendly treatment equipment.

Future outlook

with the progress of technology, the process route of acetaldehyde oxidation to produce acetic acid will be more efficient and environmentally friendly. For example, the development of new high-efficiency catalysts, the optimization of reaction conditions and the use of more precise control technology can help improve production efficiency and reduce costs.

As a classic acetic acid production process, acetaldehyde oxidation has been proved to be reliable and economical in industrial applications. Although there are some limitations, the process will still occupy an important position in the field of acetic acid production through technological improvement and innovation.