Method for refining dibasic acid dimethyl ester plasticizer

Abstract

The invention discloses a method for refining a dibasic acid dimethyl ester plasticizer, which comprises the following steps: dibasic acid dimethyl ester plasticizer crude product is refined by adopting a continuous decompression and rectification light-component and heavy-component removing method, after being filtered, the plasticizer crude product firstly enters a lightness-removing column, the lightness-removing column performs decompression operation to remove light components on the top of the lightness-removing column, the bottom materials of the lightness-removing column enter a weight-removing column to remove weight components, the weight-removing column performs decompression operation to remove monoester and little tar in the plasticizer crude product, and the top of the weight-removing column extracts the refined plasticizer produce. The plasticizer product has high purity, stable quality, lower energy consumption, simple operation and high product yield and reduces the generation of tar and environmental pollution.

Description

technical field [0001] The invention belongs to chemical separation engineering, and relates to a method for refining an aliphatic dibasic acid dimethyl plasticizer synthesized from nylon acid in adipic acid mother liquor by adopting a continuous rectification method. Background technique [0002] Aliphatic dibasic acid ester plasticizer has the characteristics of excellent low temperature performance, good impact resistance, good plasticizing efficiency and viscosity performance, and is currently mainly used as a plasticizer to improve low temperature performance. Because the price of aliphatic dibasic acid is higher, the cost of aliphatic dibasic acid ester is also higher, so the nylon acid (containing succinic acid, glutaric acid and adipic acid) obtained in the mother liquor of adipic acid ) as a raw material for plasticizers has attracted people's attention. The production process of fatty dibasic acid esters is roughly the same. Taking sulfuric acid catalysis as an ex...

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Problems solved by technology

Since there are many impurities in the plasticizer crude product obtained after the reaction, the distillation process adopts the method of batch rectification, and impurities such as methanol and water are sequentially distilled from the top of the tower, and then the plasticizer product dimethyl succinate Esters, dimethyl glutarate and dimethyl adipate mixture are steamed from the top of the tower, and batch rectification and refining plasticizer products have the following defects: 1. The product quality is unstable, and the impurity content and The acid value is unstable; 2. The energy consumption is large, and the reflux ratio required to reach the target is large; 3. There is a transitional fraction section in the intermittent distillation, and the yield is reduced; 4. The residence time of the monoester in the tower tank is too long, resulting in the generation of a large amount of tar , resulting in blockage of equipment, frequent cleaning, and increased labor costs. 5. Monoesters cannot be further recovered, resulting in a decrease in product yield; 6. Tar cannot be processed, causing serious pollution problems

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