What are the detection methods of peroxide in acetic acid?

Detection method of peroxides in acetic acid

in the chemical industry, acetic acid, as an important organic compound, is widely used in the production of vinyl acetate, cellulose acetate and other chemicals. Acetic acid may be affected by oxidation during production and storage, resulting in the formation of peroxides. The presence of peroxides will not only affect the quality of acetic acid, but may also have a negative impact on the subsequent production process and product quality. Therefore, the detection of peroxide content in acetic acid is particularly important. This article will introduce several commonly used detection methods in detail, and analyze their advantages and disadvantages.

1. Chemical titration

Chemical titration is one of the traditional methods for the determination of peroxide content in acetic acid. The method uses the change in titration endpoint to determine the peroxide content by using a known concentration of reducing agent to react with the peroxide. Common reducing agents include ferrous ammonium sulfate and potassium permanganate.

Working principle

In chemical titration, a peroxide (such as hydrogen peroxide) reacts with a reducing agent to form the corresponding product. For example, when ferrous ammonium sulfate is used as a reducing agent, peroxides will oxidize it, resulting in a color change in the solution. By measuring the amount of reducing agent consumed, the content of peroxide can be calculated.

Advantages

The
• operation is simple and the cost is low.
• Suitable for batch testing.

Disadvantages

• The operator's technical requirements are high, and it is necessary to accurately control the titration process.
• May be affected by other oxidizing substances, resulting in test results are not accurate.

2. High performance liquid chromatography (HPLC)

High performance liquid chromatography is a high-precision analysis method, which is widely used in the separation and detection of complex mixtures. In peroxide detection, HPLC can separate peroxide from other components by chromatographic column, followed by quantitative analysis by ultraviolet detector or differential refraction detector.

Working principle

HPLC uses the interaction between the mobile phase and the stationary phase to separate the sample solution through the chromatographic column by a high-pressure pump. The retention time of peroxide in the column is different from that of other components, and the signal of peroxide can be detected by the detector, so as to realize quantitative analysis.

Advantages

The
• separation efficiency is high and the detection result is accurate.
• Able to detect complex samples, suitable for high purity acetic acid detection.

Disadvantages

• The equipment cost is high and the operation is complicated.
• The need for regular maintenance of columns increases operating costs.

3. Electrochemical analysis method

Electrochemical analysis is a detection method based on electrochemical principle, which uses electrode reaction to detect the content of peroxide. Common electrochemical analysis methods include iodometry and amperometry.

iodometric method

Iodometry is a classical electrochemical analysis method. In this method, peroxide reacts with potassium iodide to form iodine, and the titration end point is judged by the color change of the starch indicator. This method is suitable for the detection of low concentration of peroxide, and the operation is simple.

amperometric method

Amperometry detects the concentration of peroxide by measuring the change in current. In this method, an oxidation reaction of the peroxide takes place on the surface of the electrode, producing a current signal. By detecting the change in current, the content of peroxide can be determined.

Advantages

• The operation is simple and the detection speed is fast.
• For online detection has high application potential.

Disadvantages

• Electrode materials and environmental conditions require higher, may affect the test results accuracy.

comprehensive analysis

The detection methods of peroxide in acetic acid have their own advantages and disadvantages. Chemical titration method is suitable for small-scale detection, low cost and simple operation, but the technical requirements for operators are higher. High performance liquid chromatography has high precision and high sensitivity, which is suitable for the detection of high purity samples, but the equipment cost is high. The electrochemical analysis method has the advantage of rapid detection and is suitable for on-line detection, but it requires high electrode materials and environmental conditions.

In practical applications, the selection of appropriate detection methods need to consider the nature of the sample, detection cost and detection accuracy and other factors. In order to ensure the accuracy of the test results, it is recommended to strictly follow the standard operating procedures during the test, and regularly calibrate and maintain the test equipment.

The detection of peroxide is of great significance to ensure the quality of acetic acid and the smooth progress of the subsequent production process. Through the understanding and selection of different detection methods, the peroxide content in acetic acid can be effectively controlled to ensure the safety and stability of the product.