CN110746295A - DOTP purification process - Google Patents
DOTP purification process Download PDFInfo
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- CN110746295A CN110746295A CN201911109215.6A CN201911109215A CN110746295A CN 110746295 A CN110746295 A CN 110746295A CN 201911109215 A CN201911109215 A CN 201911109215A CN 110746295 A CN110746295 A CN 110746295A
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/03—Preparation of carboxylic acid esters by reacting an ester group with a hydroxy group
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/48—Separation; Purification; Stabilisation; Use of additives
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/48—Separation; Purification; Stabilisation; Use of additives
- C07C67/52—Separation; Purification; Stabilisation; Use of additives by change in the physical state, e.g. crystallisation
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Crystallography & Structural Chemistry (AREA)
- Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
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.
Description
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.
Example 1: 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.
Wherein: 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 min so as to stir the PET and the octanol and accelerate the mixing of the PET and the octanol;
meanwhile, a heating temperature rising device is further arranged in the reaction kettle adopted in the S1, and the heating temperature is 60 ℃ so as to accelerate the reaction of the PET and the octanol.
Further, the falling film evaporator in S2 takes a form of advection for evaporation of the mixed liquid.
Specifically, when the phase separator 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.
In addition, the gas separated by the phase separator in S5 is adsorbed, filtered and discharged.
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.
Example 2: 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.
Wherein: 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 45 min, so that the PET and the octanol are stirred, and the mixing of the PET and the octanol is accelerated;
meanwhile, a heating temperature rising device is further arranged in the reaction kettle adopted in the S1, and the heating temperature is 80 ℃ so as to accelerate the reaction of the PET and the octanol.
Further, the falling film evaporator in S2 takes a form of advection for evaporation of the mixed liquid.
Specifically, when the phase separator 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.
In addition, the gas separated by the phase separator in S5 is adsorbed, filtered and discharged.
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.
Example 3: 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.
Wherein: 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 60 min, so that the PET and the octanol are stirred, and the mixing of the PET and the octanol is accelerated;
meanwhile, a heating temperature rising device is further arranged in the reaction kettle adopted in the S1, and the heating temperature is 120 ℃ so as to accelerate the reaction of the PET and the octanol.
Further, the falling film evaporator in S2 takes a form of advection for evaporation of the mixed liquid.
Specifically, when the phase separator 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.
In addition, the gas separated by the phase separator in S5 is adsorbed, filtered and discharged.
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.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (7)
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.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911109215.6A CN110746295A (en) | 2019-11-13 | 2019-11-13 | DOTP purification process |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201911109215.6A CN110746295A (en) | 2019-11-13 | 2019-11-13 | DOTP purification process |
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| CN110746295A true CN110746295A (en) | 2020-02-04 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112266325A (en) * | 2020-09-24 | 2021-01-26 | 山东润林新材料科技有限公司 | Continuous distillation system for producing DOTP by regenerating PTA |
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| EP0388197A1 (en) * | 1989-03-15 | 1990-09-19 | Synergistics Industries Limited | Production of terephthalate esters by degradative transesterification of scrap or virgin terephthalate polyesters |
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| US20170113995A1 (en) * | 2015-10-23 | 2017-04-27 | Columbia Insurance Company | Process for production of an ester and diol from reclaimed carpet material |
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2019
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112266325A (en) * | 2020-09-24 | 2021-01-26 | 山东润林新材料科技有限公司 | Continuous distillation system for producing DOTP by regenerating PTA |
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