What are the main steps in the production of methyl methacrylate by acetone cyanohydrin?

What are the main steps in the production of methyl methacrylate by acetone cyanohydrin?

Methyl methacrylate (MMA) is an important organic compound, which is widely used in plastics, coatings, adhesives and electronic materials. The acetone cyanohydrin method is a classic MMA production process, which is still widely used because of its mild reaction conditions and easy access to raw materials. In this paper, the main steps of methyl methacrylate production by acetone cyanohydrin method will be analyzed in detail, and its process characteristics and optimization direction will be discussed.

1. The basic principle of acetone cyanohydrin method

the core reaction of the acetone cyanohydrin process is the production of β-alanine by acetone and hydrocyanic acid (HCN) under specific conditions, followed by further reaction and refining to obtain MMA. The method uses acetone as raw material, realizes organic synthesis by introducing cyano, and finally converts to methyl methacrylate.

2. Main steps of acetone cyanohydrin method

the process of producing MMA by acetone cyanohydrin can be divided into the following key steps:

(1) Reaction of acetone with hydrocyanic acid

in the first critical step, acetone (CH3COCH3) is added to hydrocyanic acid (HCN) over an acidic catalyst to produce β-alanine (CH2CH2C(OH)NH2). This reaction is usually carried out at a relatively high temperature (about 80-100°C) and a relatively high pressure to ensure that the reaction proceeds smoothly. The product of the reaction, β-alanine, is a key intermediate for subsequent reactions.

(2) Hydrolysis and esterification of β-alanine

the hydrolysis of β-alanine is the second key step in the acetone cyanohydrin process. During the hydrolysis, the cyano group in β-alanine is hydrolyzed to give acrylic acid (CH2CH2COOH). Subsequently, acrylic acid and methanol are esterified under acidic conditions to produce methyl methacrylate (MMA). This reaction is at the heart of the process and determines the yield and quality of the final product.

(3) Distillation and purification

after the reaction, the product needs to undergo rectification and purification steps to remove impurities and by-products and obtain high-purity methyl methacrylate. In the distillation process, by controlling the temperature and pressure, the target product can be effectively separated to ensure that the quality of the product meets industrial standards.

3. Process characteristics of acetone cyanohydrin method

as a classic MMA production process, acetone cyanohydrin has the following remarkable characteristics:

• raw materials are simple and easy to obtain acetone and hydrocyanic acid are commonly used chemical raw materials, a wide range of sources and low cost.
• mild reaction conditions compared with other processes (such as propylene oxidation), the reaction conditions of the acetone cyanohydrin method are milder, and the equipment investment and operating costs are lower.
• Mature and stable process after long-term industrial application, the process and technology of acetone cyanohydrin method have been very mature and the production stability is high.

4. Optimization direction of acetone cyanohydrin method

although the acetone cyanohydrin method has many advantages, there are still some areas for improvement in actual production. For example:

• reaction efficiency improvement by optimizing the type of catalyst and reaction conditions, the reaction efficiency of acetone and hydrocyanic acid can be further improved and the occurrence of side reactions can be reduced.
• Cost reduction: The toxicity and corrosion of hydrocyanic acid are high. How to reduce its dosage and reduce the corrosion of equipment is an important direction for the optimization of acetone cyanohydrin method.
• Environmental treatment: A certain amount of by-products and wastewater will be produced in the production process of acetone cyanohydrin. How to achieve green production and reduce the impact on the environment is the focus of future research.

5. Summary and Prospect

as a classic methyl methacrylate production process, acetone cyanohydrin has an important position in the chemical industry. Through the analysis of its main steps, it can be seen that the method has the advantages of simple raw materials and mature process, but there is also room for further optimization. In the future, with the promotion of green chemistry and the concept of sustainable development, the acetone cyanohydrin method will develop in a more efficient and environmentally friendly direction, providing better technical support for the production of MMA.