阅读说明：本技术 一种dotp提纯工艺 (DOTP purification process ) 是由 魏建设 赵东方 崔贵强 张金祥 兰芝东 于 2019-11-13 设计创作，主要内容包括：本发明公开了一种DOTP提纯工艺,涉及DOTP制备技术领域,该工艺包括：将PET和辛醇加入反应釜中进行反应,生成DOTP和乙二醇的混合液；将S1中产生的混合液加入降膜蒸发器中进行蒸发,生成DOTP和乙二醇的混合气体；将S2中生成的混合气体由进气口加入提纯塔中,进行提纯,提纯后的气体排进冷凝器中；冷凝器将提纯后的气体进行冷凝,生成液体；将S4中生成的液体加进分相器,分相器将液体进行分离,以将气体、液体和残渣进行分离；将S5中分离出的液体通过出料控制阀排出并收集,即可得到提纯后的DOTP液体,本发明提供的提纯工艺具有节能环保、降低生产成本的特点,同时该工艺可通过控制回流比,以控制提纯后液体的纯度,更加适用于PVC的主增塑剂。(The invention discloses a DOTP purification process, relating to the technical field of DOTP preparation, and the process comprises the following steps: adding PET and octanol into a reaction kettle for reaction to generate a mixed solution of DOTP and glycol; adding the mixed solution generated in the S1 into a falling film evaporator for evaporation to generate a mixed gas of DOTP and glycol; adding the mixed gas generated in the step S2 into a purification tower through a gas inlet, purifying, and discharging the purified gas into a condenser; condensing the purified gas by using a condenser to generate liquid; adding the liquid generated in the step S4 into a phase separator, and separating the liquid by the phase separator to separate gas, liquid and residue; the liquid separated in the S5 is discharged through a discharge control valve and collected, and then the purified DOTP liquid can be obtained.)

1. A DOTP purification process is characterized in that: the purification process comprises the following steps:

s1, adding PET and octanol into the reaction kettle, so that the PET and the octanol react to generate a mixed solution of DOTP and ethylene glycol;

s2, adding the mixed liquid generated in the S1 into a falling-film evaporator, and evaporating the mixed liquid in the falling-film evaporator to generate a mixed gas of DOTP and glycol;

s3, adding the mixed gas generated in the S2 into a purification tower through a gas inlet, continuously performing gas-liquid exchange through the contact of the mixed gas and a reflux liquid in the purification tower and a packing cavity, so that ethylene glycol is reacted to achieve the purpose of purification, and then discharging the purified gas into a condenser;

s4, condensing the purified gas by a condenser to generate liquid;

s5, adding the liquid generated in the S4 into a phase separator, and separating the liquid by the phase separator to form gas, liquid and residues for separation;

and S6, discharging and collecting the liquid separated in the S5 through a discharge control valve to obtain the purified DOTP liquid.

2. A DOTP purification process according to claim 1, characterized in that: and a stirrer is arranged in a reaction kettle adopted in the S1, the stirring speed is 2900 r/min, and the stirring is carried out for 30-60 min, so that the PET and the octanol are stirred, and the mixing of the PET and the octanol is accelerated.

3. A DOTP purification process according to claim 1, characterized in that: the reaction kettle adopted in the S1 is also internally provided with a heating temperature rise device, and the heating temperature is 60-120 ℃ so as to accelerate the reaction of the PET and the octanol.

4. A DOTP purification process according to claim 1, characterized in that: the falling film evaporator in S2 is in the form of advection for evaporation of the mixed liquid.

5. A DOTP purification process according to claim 1, characterized in that: when the phase splitter separates the liquid in S5, the method further includes:

(1) if the purity of the liquid is insufficient, the liquid flows back into the falling film evaporator through a reflux control valve, and the steps of S2, S3, S4 and S5 are repeated to carry out purification again until the purity of the separated liquid meets the requirement;

(2) if the purity of the liquid meets the requirement, the liquid is discharged through the discharge control valve.

6. A DOTP purification process according to claim 1, characterized in that: in addition, the gas separated by the phase separator in S5 is adsorbed, filtered and discharged.

7. A DOTP purification process according to claim 1, characterized in that: in the purification process, the reflux ratio in the purification process can be controlled by controlling the opening degrees of the reflux control valve and the discharge control valve, so that the purity of the discharged liquid is controlled, and the DOTP content is over 99.6 percent.

Technical Field

The invention belongs to the technical field of DOTP preparation, and particularly relates to a DOTP purification process.

Background

DOTP is dioctyl terephthalate, which is used as a main plasticizer of PVC, the volatility resistance, the heat resistance, the cold resistance, the weather resistance and the oil-resistant water extraction performance of the DOP are obviously superior to those of DOP, the toxicity is lower than that of DOP, and the plasticizing efficiency is slightly lower than that of DOP. The DOTP is particularly suitable for products with high temperature resistance, low temperature resistance and durability, and is mainly used for manufacturing high temperature resistant cable materials, plastic parts for vehicles, high-grade artificial leather and the like.

However, during the preparation of DOTP, other byproducts are easily generated, which results in insufficient purity of DOTP and affects the performance of DOTP, and therefore, a DOTP purification process is needed to purify DOTP to ensure the performance of DOTP.

Disclosure of Invention

The invention aims to provide a DOTP purification process, which aims to solve the problems in the background art, effectively improve the purity of DOTP and achieve the effects of good performance and better practicability.

In order to achieve the purpose, the invention provides the following technical scheme: a DOTP purification process, said purification process comprising the steps of:

s1, adding PET and octanol into the reaction kettle, so that the PET and the octanol react to generate a mixed solution of DOTP and ethylene glycol;

s2, adding the mixed liquid generated in the S1 into a falling-film evaporator, and evaporating the mixed liquid in the falling-film evaporator to generate a mixed gas of DOTP and glycol;

s3, adding the mixed gas generated in the S2 into a purification tower through a gas inlet, continuously performing gas-liquid exchange through the contact of the mixed gas and a reflux liquid in the purification tower and a packing cavity, so that ethylene glycol is reacted to achieve the purpose of purification, and then discharging the purified gas into a condenser;

s4, condensing the purified gas by a condenser to generate liquid;

s5, adding the liquid generated in the S4 into a phase separator, and separating the liquid by the phase separator to form gas, liquid and residues for separation;

and S6, discharging and collecting the liquid separated in the S5 through a discharge control valve to obtain the purified DOTP liquid.

Preferably, the reaction kettle adopted in the step S1 is internally provided with a stirrer, the stirring speed is 2900 r/min, and the stirring is carried out for 30-60 min, so that the PET and the octanol are stirred, and the mixing of the PET and the octanol is accelerated.

Preferably, the reaction kettle adopted in the S1 is further internally provided with a heating temperature rise device, and the heating temperature is 60-120 ℃ so as to accelerate the reaction of the PET and the octanol.

Preferably, the falling film evaporator in S2 is in the form of advection for evaporation of the mixed liquid.

Preferably, when the phase splitter separates the liquid in S5, the method further includes:

(1) if the purity of the liquid is insufficient, the liquid flows back into the falling film evaporator through a reflux control valve, and the steps of S2, S3, S4 and S5 are repeated to carry out purification again until the purity of the separated liquid meets the requirement;

(2) if the purity of the liquid meets the requirement, the liquid is discharged through the discharge control valve.

Preferably, the gas separated by the phase separator in S5 is discharged after adsorption and filtration.

Preferably, in the purification process, the reflux ratio in the purification process can be controlled by controlling the opening degree of the reflux control valve and the discharge control valve, so that the purity of the discharged liquid is controlled, and the DOTP content is up to more than 99.6%.

Compared with the prior art, the invention has the beneficial effects that:

(1) the purification process provided by the invention has the characteristics of energy conservation, environmental protection and production cost reduction, and meanwhile, the process can control the purity of the purified liquid by controlling the reflux ratio, so that the content of DOTP is up to more than 99.6%, and the DOTP has good high temperature resistance, low temperature resistance and durability, reaches the use standard of a plasticizer, and is more suitable for the main plasticizer of PVC.

(2) The process provided by the invention is short in flow, simple and convenient to operate, high in automation degree, and beneficial to improving the working efficiency of workers, effectively reducing the labor intensity of the workers and further improving the production benefit of DOTP.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.