How to purify industrial grade MIBK to electronic grade (purity ≥ 99.9%) by fractionation technology?

How to purify industrial grade MIBK to electronic grade (purity ≥ 99.9%) by fractionation technology?

MIBK (methyl isobutyl ketone) is an important industrial solvent, which is widely used in electronic manufacturing, printing and chemical industry. The purity of industrial grade MIBK is usually about 98%, which is difficult to meet the requirements of electronic grade MIBK (purity ≥ 99.9). In order to meet this demand, fractionation technology has become a key method for the purification of MIBK. This article will analyze in detail how to purify industrial grade MIBK to electronic grade by fractionation technology, and discuss related process optimization and quality control measures.

1. Understand MIBK properties and purification objectives

MIBK is a colorless, flammable organic compound with a special odor and relatively stable chemical properties. Its industrial grade products often contains impurities, such as water, acidic substances, light fractions and heavy fractions. These impurities can seriously affect its application in electronic manufacturing. For example, in semiconductor manufacturing, MIBK is used as a cleaning agent or detergent, which requires extremely high purity. Therefore, it is necessary to purify industrial grade MIBK to electronic grade (purity> 99.9%).

2. Fractionation technology basic principle

Fractionation is a separation technology based on the difference of boiling points of substances, which is widely used in chemical industry. The boiling point of MIBK is about 77°C, while the boiling point of its impurities is usually different from that of MIBK. Through the fractionation process, MIBK can be separated from impurities, thereby improving its purity. The core equipment of fractionation is the distillation column, and its working principle includes the steps of feed, vaporization, lift, condensation and collection.

3. Industrial grade MIBK fractionation purification process

To purify industrial MIBK to electronic grade, the following steps are usually required:

3.1 preliminary purification: distillation and rectification

Technical grade MIBK was initially purified by distillation. Distillation can remove impurities with significantly different boiling points, such as water and acids. Subsequently, MIBK is further separated from other impurities using rectification techniques. The design of the distillation column directly affects the separation efficiency, and high-efficiency packings or trays are usually used to improve the separation effect.

3.2 feed pretreatment

In the fractionation process, the pretreatment of the feed is critical. It should be ensured that the feed is free of moisture, as water will form an azeotrope with MIBK and affect the separation. Acidic impurities, such as sulfuric acid or nitric acid, need to be removed, which may cause corrosion to equipment or contaminate the product.

3.3 distillation column operation optimization

The operating parameters of the distillation column, such as temperature, pressure and flow rate, need to be strictly controlled. Temperature control is key because the boiling point of MIBK is sensitive to temperature changes. Generally, the top temperature of the rectification column is controlled at about 70°C, and the bottom temperature is slightly higher. Vacuum operation can reduce the boiling point and help improve the separation efficiency.

3.4 impurity separation and collection

During the rectification process, MIBK is collected in a specific fraction, while impurities are distributed in other fractions. For example, the light fraction may contain low boiling impurities, while the heavy fraction may contain high boiling impurities. By precisely controlling the fraction cutting, the purity of MIBK can be ensured to reach more than 99.9%.

4. Impurity analysis and control

In the purification process, the type and content of impurities directly affect the purity of the final product. The following is an analysis of common impurities:

4.1 water and acidic impurities

Water and acidic impurities are the most common impurities in MIBK, usually originating from raw materials or contamination during storage. These impurities affect the stability of MIBK and may corrode equipment. Therefore, these impurities need to be removed by distillation or adsorbent before fractionation.

4.2 light and heavy fractions

Light fractions (e. g., ketones) and heavy fractions (e. g., high boilers) are minor impurities in MIBK. The light fraction is usually removed during the rectification process, while the heavy fraction may remain in the bottom of the column. By optimizing the operating parameters of the distillation column, the content of these impurities can be effectively reduced.

4.3 impurity monitoring and detection

In order to ensure that the impurity content meets the requirements, the purified MIBK needs to be strictly tested. Common detection methods include gas chromatography (GC) and mass spectrometry (MS), which can accurately determine the content of impurities in MIBK.

5. Quality control and process optimization

Quality control and process optimization are essential to ensure that MIBK is electronic-grade pure.

5.1 impurity source control

The generation of impurities mainly comes from raw materials, equipment and process. Therefore, it is necessary to control the introduction of impurities from the source, such as the selection of high-quality raw materials and clean production equipment.

5.2 process parameter optimization

The operating parameters of the distillation column directly affect the purification effect. Through simulations and experimental optimization, the best temperature, pressure and flow parameters can be found, thereby improving the separation efficiency.

5.3 to establish a strict testing system

In the process of purification, a strict detection system should be established to ensure that each batch of MIBK meets the electronic standard. The detection indicators include purity, moisture content, acid value and impurity types.

6. Fractionation technology of environmental protection and economy

Fractionation technology is not only efficient, but also environmentally friendly and economical. Through the optimization design of the distillation column, the energy consumption and the production of by-products can be reduced. The fractionation process has a high recovery rate and is suitable for large-scale industrial production.

Summary

Through fractionation technology, industrial MIBK can be purified to electronic grade (purity ≥ 99.9%) to meet the high standards of the electronics manufacturing industry. This paper introduces the principle, process and optimization measures of fractionation technology in detail, and discusses the importance of impurity control and quality detection. In the future, with the continuous progress of technology, fractionation technology will be more efficient and environmentally friendly, providing strong support for the purification and application of MIBK.