As a highly active pre-emergence herbicide, acetochlor is widely used for weed control in corn, soybean and other crop fields. During its production process, impurities such as unreacted raw materials, inorganic salts and organic solvents remaining in the reaction liquid need to be removed by efficient separation technology to meet the purity requirements of pesticide formulations. The traditional gravity stratification method has been difficult to meet the needs of modern chemical production due to its defects such as low separation efficiency, easy emulsification and high energy consumption. Centrifugal extractor achieves rapid mixing and separation of liquid and liquid phases with ultra-high-speed centrifugal force fields, becoming the core equipment of the acetochlor post-treatment process. This article analyzes from three aspects: technical principles, application advantages and equipment selection, providing practical reference for the industry.

1. Principle and process advantages of centrifugal extraction technology

The centrifugal extractor uses the centrifugal force (up to a thousand times greater than gravity) generated by the high-speed rotation of the drum to drive the organic phase and the aqueous phase to complete mixed mass transfer and centrifugal separation in the equipment. Its technical advantages are reflected in the following aspects:
 

• Efficient Mass Transfer And Separation

LC centrifugal extractor adopts a non-annular gap mixing structure, the drum rotates independently, and the stirring paddle is optimized according to the material characteristics, so that the acetochlor reaction liquid and the washing water are fully in contact, and the mass transfer efficiency is increased by 3-5 times compared with traditional reactor. For example, in the four-stage acid washing & three-stage water washing process, the processing capacity of a single device reaches 10-50m³/h, the separation time is shortened to 20 minutes/batch, and the product purity is increased to 99.2%.
 

• Emulsification Inhibition And Continuous Production

The feature of centrifugal force separation can avoid the retention of emulsions caused by changes in interfacial tension during acid/alkaline washing and reduce the loss of intermediates. It supports multi-stage countercurrent washing (such as four-stage acid washing + three-stage water washing) to meet the needs of large-scale production. A pesticide factory shows that after using a centrifugal extractor, the solvent recovery rate increased from 75% to 92%, and the wastewater COD decreased from 5000mg/L to 800mg/L, meeting the direct biochemical treatment standards.

• Energy Saving And Intelligent Control

By integrating online pH and turbidity monitoring modules, the equipment can adaptively adjust the number of washing stages, reducing energy consumption by 30% and labor costs by 50%. The coupled membrane separation technology builds a "centrifugal extraction-membrane concentration-solvent regeneration" closed-loop system to achieve zero wastewater discharge.


2. Acetochlor Separation And Purification Process


 Acid and alkali cleaning process

Mixing the reaction solution and dilute sulfuric acid,  unreacted chloroacetyl chloride and other acidic impurities are quickly separated and removed by centrifugal extractor, pH control accuracy  ±0.2. After the residual acid is neutralized with sodium hydroxide solution, the purity of the organic phase of acetochlor can be increased to more than 98%, 15% higher than the traditional process.

Scrubbing And Solvent Recovery 

The three-stage scrubbing,  to wash continuously times with deionized water to remove inorganic salts and water-soluble impurities. The centrifuge has a single separation time of <2 minutes, and water consumption is reduced by 40%. For high-purity demand (such as pharmaceutical-grade acetochlor), added 1stage of scrubbing to reduce the conductivity index to below 10μS/cm. After extraction, the mixed liquid is separated by a centrifuge, and the recovered organic solvent (such as toluene) has a purity of 99.5% and can be directly reused in the previous reaction process.


LC series centrifugal extractor achieves efficient and green extraction of acetochlor through non-thermal centrifugal separation technology. Its core advantages include:

Process innovation

Physical separation + precise temperature control: The gradient temperature control system supports multi-stage temperature control of 40-75℃ to avoid oxidation and degradation of vitamin E (Note: Here, the vitamin E case is used as an analogy, and the acetochlor process needs to be adjusted in a targeted manner), and the extract purity is ≥98%.
Multi-stage series process: supports 5-stage countercurrent extraction, and the acetochlor recovery rate of a single device is ≥95%, which is 35% higher than the traditional process.
Equipment performance

Corrosion resistance + energy saving + intelligence: SS316L + fluorine material coating is corrosion-resistant, with a service life of ≥10 years; non-annular gap mixing design reduces energy consumption by 20%, and the processing cost per ton is reduced by 40% compared with molecular distillation; the PLC system supports remote fault diagnosis and process optimization.

Our new innovation of centrifugal extractor on post-treatment process of acetochlor has significantly improved product quality and production efficiency, and reducing environmental load. Shandong Liancui's LC series of centrifugal extractors have shown excellent application in the field of pesticide intermediates due to our technological breakthroughs and model adaptability. It is recommended that industry users give priority to this series of products to achieve a win-win situation of green manufacturing and economic benefits.