Ester exchange equipment and method for producing DOTP from PET

Abstract

The invention provides ester exchange equipment and an ester exchange method for producing DOTP from PET. The equipment comprises an esterification kettle, a condenser, a primary absorption tank and asecondary absorption tank which are connected in sequence, wherein the primary absorption tank and the secondary absorption tank are arranged behind the condenser, and ethylene glycol is subjected tosecondary adsorption, so that the esterification key point is easy to control, the concentration of the ethylene glycol is increased by about 2.4 times compared with that of the ethylene glycol subjected to primary adsorption, and heat energy is saved for ethylene glycol refining. The pipeline between the condenser and the primary absorption tank is communicated with an earlier-stage water tank,PET is dehydrated before DOTP esterification in PET production, and dehydrated water enters the earlier-stage water tank and is not mixed with ethylene glycol water, so that the ethylene glycol wateris recycled and balanced, and the esterification sewage discharge amount is reduced; an early-stage water tank is arranged to specially collect early-stage water and is not mixed with other substances, so that an esterification end point is easy to master.

Description

technical field [0001] The invention relates to DOTP production equipment and a process method, in particular to a transesterification equipment and method for producing DOTP using PET as a raw material. Background technique [0002] Dioctyl terephthalate (DOTP for short) is a plasticizer with excellent performance. It has good electrical and thermal properties. It has good speed-up effect and low volatility when used in cable materials. It is widely used in heat-resistant It is an ideal plasticizer for producing temperature-resistant 70°C cable materials and other volatilization-resistant PVC products. It also has good cold resistance and is an excellent environmentally friendly plasticizer. [0003] The traditional DOTP production method uses terephthalic acid and octanol as raw materials to directly carry out esterification reaction, but due to the high price of terephthalic acid raw materials, the production cost is relatively high. In order to reduce production costs, ...

AI Technical Summary

Problems solved by technology

DOTP is produced by the PET transesterification method. Whether the esterification is qualified is determined by the ethylene glycol condensed in the laboratory condenser 10. If the ethylene glycol detection after condensation is ≤ 2%, it is considered qualified. The existing production equipment uses the absorption tank 6. Once the adsorption is performed, the ethylene glycol will not be adsorbed cleanly, and it will be difficult to pass the test when it is returned to the esterification tank. The production is difficult, and the end point of the esterification is not easy to control.

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