Process for producing dioctyl terephthalate by semi-continuous method

Abstract

The invention discloses a process for producing dioctyl terephthalate by a semi-continuous method in the technical field of chemical production. The method sequentially comprises the following steps:firstly, carrying out a batch-type esterification reaction in two esterification kettles: in a first esterification kettle, taking terephthalic acid and isooctyl alcohol as raw materials to carry outa mono-esterification reaction with a catalyst (tetrabutyl titanate), adding a mixture obtained after the reaction into a second esterification kettle in batches, and simultaneously adding the catalyst (tetrabutyl titanate) to carry out a dual-esterification reaction; and continuously neutralizing and washing the obtained mixture, removing alcohol, stripping, decolorizing and filtering to obtain dioctyl terephthalate. According to the invention, the automation degree, the product quality and the labor productivity are improved, and the time is saved. The process has the advantages of stable product quality, low labor intensity, high economic benefit and the like.

Description

technical field [0001] The invention relates to a process for producing dioctyl terephthalate, in particular to a process for producing dioctyl terephthalate using a semi-continuous method of terephthalic acid and isooctyl ester. It belongs to the technical field of chemical production. Background technique [0002] At present, there are more than a dozen categories of plasticizers in the world, with a total of more than 500 varieties, with a total annual output of more than 5 million tons, and more than 70% are phthalates, of which diisooctyl phthalate (DOP) has good performance, but due to the shortcomings of DOP polluting the environment and high toxicity, it has been banned from export by many EU countries, and the abuse of this plasticizer has also been banned in my country. [0003] Diisooctyl terephthalate (DOTP) plasticizer has good electrical and thermal properties, and can replace DOP in PVC plastic electrical wire sheaths, and can also be used in the production of...

AI Technical Summary

Problems solved by technology

[0006] (1) The control of the batch production process is relatively complex, including various control variables such as temperature and liquid level, and has strict requirements on production conditions;

[0007] (2) The intermittent production cycle is long, the energy consumption is large, and the equipment utilization efficiency is low;

[0008] (3) Batch type is only suitable for small-scale production, and the product stability is low

[0009] In the domestic research on the production method of dioctyl terephthalate, although continuous production is mentioned, the continuous production process involved is relatively cumbersome, including esterification, dealcoholization, neutralization and washing, air stripping, adsorption and filtration. , wastewater treatment and other multiple processes, many equipments are used, the equipment utilization rate is low, the energy consumption is large, the environmental pollution is relatively large, and it is not in line with the actual industrial production