阅读说明：本技术 一种三乙二醇二正辛酸酯的制备方法 (Preparation method of triethylene glycol di-n-caprylate ) 是由 孟永财 孟爱国 于 2021-09-08 设计创作，主要内容包括：本申请涉及一种三乙二醇二正辛酸酯的制备方法,包括以下步骤：S1：于三乙二醇中加入正辛酸,在催化剂的作用下,升温至120～130℃进行酯化反应,所述催化剂为钛酸四丁酯和/或钛酸四异丁酯；S2：酯化反应完毕后,通过减压蒸馏脱除正辛酸,得到三乙二醇二正辛酸酯液体粗品；S3：将三乙二醇二正辛酸酯液体粗品进行中和、水洗、脱水,通过膜蒸发器去除剩余水分及杂质,再通过分子蒸馏获得三乙二醇二正辛酸酯成品。(The application relates to a preparation method of triethylene glycol di-n-caprylate, which comprises the following steps: s1: adding n-octanoic acid into triethylene glycol, and heating to 120-130 ℃ under the action of a catalyst to perform an esterification reaction, wherein the catalyst is tetrabutyl titanate and/or tetraisobutyl titanate; s2: after the esterification reaction is finished, removing n-caprylic acid by reduced pressure distillation to obtain a triethylene glycol di-n-caprylate liquid crude product; s3: neutralizing, washing and dehydrating the triethylene glycol di-n-caprylate liquid crude product, removing residual water and impurities through a film evaporator, and performing molecular distillation to obtain a triethylene glycol di-n-caprylate finished product.)

1. A preparation method of triethylene glycol di-n-caprylate is characterized by comprising the following steps:

s1: adding n-octanoic acid into triethylene glycol, and heating to 120-130 ℃ under the action of a catalyst to perform an esterification reaction, wherein the catalyst is tetrabutyl titanate and/or tetraisobutyl titanate; the reaction equation is expressed as follows:

s2: after the esterification reaction is finished, removing n-caprylic acid by reduced pressure distillation to obtain a triethylene glycol di-n-caprylate liquid crude product;

s3: neutralizing, washing and dehydrating the triethylene glycol di-n-caprylate liquid crude product, removing residual water and impurities through a film evaporator, and performing molecular distillation to obtain a triethylene glycol di-n-caprylate finished product.

2. The method of claim 1, wherein in step S1, the molar amount of the catalyst is 0.02 mol% to 0.04 mol% of the molar amount of triethylene glycol.

3. The process for preparing triethylene glycol di-n-caprylate according to claim 1 or 2, wherein in step S1, the molar amount of n-caprylic acid is at least 20 mol% excess based on the hydroxyl group of triethylene glycol to be esterified.

4. The process for preparing triethylene glycol di-n-caprylate according to any one of claims 1 to 3, wherein in step S2, the excess n-caprylic acid that has not reacted in the esterification reaction is recovered by distillation and then recycled.

5. The process for preparing triethylene glycol di-n-caprylate as claimed in any one of claims 1 to 4, wherein in step S3, the crude liquid triethylene glycol di-n-caprylate is neutralized by adding alkali solution so that the acid value of the solution is less than 0.1mg KOH/g.

6. The method for preparing triethylene glycol di-n-caprylate as claimed in claim 5, wherein the alkali solution is 7% sodium hydroxide solution.

7. The method for preparing triethylene glycol di-n-caprylate according to any one of claims 1 to 6, wherein in step S3, the dehydration method is vacuum reduced pressure dehydration.

8. The process for the preparation of triethylene glycol di-n-caprylate as claimed in claim 7, wherein the vacuum dehydration is performed under the following conditions: the vacuum was 3-5kPa and the temperature 118-.

9. The method for preparing triethylene glycol di-n-caprylate according to any one of claims 1 to 8, wherein in step S3, the conditions for removing residual moisture and impurities by a film evaporator are preferably as follows: the temperature is 143-147 ℃, and the vacuum degree is 3-5 Pa.

10. The method for preparing triethylene glycol di-n-caprylate according to any one of claims 1 to 9, wherein in step S3, the conditions of molecular distillation are as follows: the distillation temperature is 98-102 ℃, and the vacuum degree is 3-5 Pa.

Technical Field

The application belongs to the technical field of ester plasticizers, and particularly relates to a preparation method of triethylene glycol di-n-caprylate.

Background

The plasticizer is added to increase the plasticity and fluidity of the processed rubber, plastic, paint and other high polymers during molding and enables the finished product to have flexibility, is an essential additive in the plastic industry, and has become the first world-wide country with high production and consumption resistance. Triethylene glycol dicarboxylate is a kind of plasticizer especially suitable for polyvinyl butyral (PVB) processing, at present, triethylene glycol diisocaprylate plasticizer is mostly adopted in the market, triethylene glycol diisocaprylate is solvent-type cold-resistant plasticizer, has the characteristics of excellent low temperature, durability, oil resistance, ultraviolet irradiation resistance and antistatic property, low viscosity and certain lubricity, and the like, and the molecular structure of the triethylene glycol diisocaprylate plasticizer enables a plastic product to have good chroma and transparency, and the polarity similar to that of resin enables the plastic product to be well soluble with the resin, so the triethylene glycol dicarboxylate is widely applied to multiple fields of PVB safety films, synthetic rubber, vinyl resin, PVC, industrial coating, sealing materials and the like.

Triethylene glycol diisocaprylate is formed by reacting isooctanoic acid and triethylene glycol, the reaction is a typical esterification dehydration reaction, the reaction influence factors comprise reaction temperature, reaction time, reaction environment pressure, catalyst types, the amount ratio of acid-alcohol substances and the like, the reaction of isooctanoic acid and triethylene glycol needs to be carried out under the conditions of high temperature, high pressure and negative pressure, the reaction conditions are strict, the production and manufacturing cost of the raw material of isooctanoic acid is high, and the triethylene glycol diisocaprylate is high. In addition, although the prior art has disclosed a method for preparing triethylene glycol di-n-caprylate, the preparation method is also complicated, or the preparation method requires the use of a catalyst which is relatively expensive/difficult to prepare, for example, the patent of CN106488904A discloses that the preparation of triethylene glycol di-n-caprylate requires the use of a membrane biocatalyst (immobilized Candida antarctica lipase immobilized on a porous fluoropolymer carrier).

Disclosure of Invention

The technical problem to be solved by the invention is as follows: aiming at solving the defects of high production cost, complex/harsh preparation conditions and the like of triethylene glycol dicarboxylate serving as a plasticizer in the prior art, the preparation method of triethylene glycol di-n-caprylate is provided.

The technical scheme adopted by the invention for solving the technical problems is as follows:

a preparation method of triethylene glycol di-n-caprylate comprises the following steps:

s1: adding n-octanoic acid into triethylene glycol, and heating to 120-130 ℃ under the action of a catalyst to perform an esterification reaction, wherein the catalyst is tetrabutyl titanate and/or tetraisobutyl titanate; the reaction equation is expressed as follows:

s2: after the esterification reaction is finished, removing n-caprylic acid by reduced pressure distillation to obtain a triethylene glycol di-n-caprylate liquid crude product;

s3: neutralizing, washing and dehydrating the triethylene glycol di-n-caprylate liquid crude product, removing residual water and impurities through a film evaporator, and performing molecular distillation to obtain a triethylene glycol di-n-caprylate finished product.

Preferably, in step S1, the molar amount of the catalyst is 0.02 mol% to 0.04 mol% of the molar amount of the triethylene glycol.

Preferably, in step S1, the molar amount of n-octanoic acid is used in an excess of at least 20 mol%, based on the hydroxyl groups of the triethylene glycol to be esterified.

Preferably, in step S2, the excess n-octanoic acid that has not reacted in the esterification reaction is recovered by distillation and then recycled.

Preferably, in step S3, the triethylene glycol di-n-caprylate liquid crude product is neutralized by adding alkali liquor, preferably 7% sodium hydroxide solution, so that the acid value of the solution is less than 0.1mg KOH/g.

Preferably, in step S3, the dehydration method is vacuum reduced pressure dehydration, and the conditions of the vacuum reduced pressure dehydration are preferably as follows: the vacuum was 3-5kPa and the temperature 118-.

Preferably, in step S3, the conditions for removing the remaining moisture and impurities by the film evaporator are preferably: the temperature is 143-147 ℃, and the vacuum degree is 3-5 Pa.

Preferably, in step S3, the conditions of molecular distillation are: the distillation temperature is 98-102 ℃, and the vacuum degree is 3-5 Pa.

The invention has the beneficial effects that:

(1) the preparation method of triethylene glycol di-n-caprylate is simple, high-purity triethylene glycol di-n-caprylate can be obtained through esterification reaction at low temperature and normal pressure under the action of a small amount of high-selectivity catalyst, the reaction condition is mild and easy to control, the yield of triethylene glycol di-n-caprylate is extremely high, the yield and the purity can reach more than 99%, the chromaticity of the product is good, and the shelf life is as long as more than 2 years.

(2) The triethylene glycol di-n-caprylate plasticizer prepared by the invention has better performance than triethylene glycol di-iso-caprylate plasticizer, and the cost of the used n-caprylic acid raw material is low, so that the production cost is greatly reduced compared with the production cost of using only iso-caprylic acid instead of n-caprylic acid by using triethylene glycol di-iso-caprylate plasticizer.

Drawings

The technical solution of the present application is further explained below with reference to the drawings and the embodiments.

FIG. 1 is a gas chromatogram of triethylene glycol di-n-caprylate of the present application;

FIG. 2 is a chart of melting point reports for triethylene glycol di-n-octanoate according to the present application.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.

The technical solution of the present application will be described in detail with reference to the following examples.

Example 1

The embodiment provides a preparation method of triethylene glycol di-n-caprylate, which comprises the following steps:

s1: in a heatable 10m equipped with stirrer, internal thermometer and water separator³Charging triethylene glycol, n-octanoic acid accounting for 20 mol% of hydroxyl to be esterified and tetraisobutyl titanate accounting for 0.04 mol% of the molar amount of the triethylene glycol into a reaction kettle, starting stirring, then starting condensed water and heating to react at 125 ℃, removing formed reaction water on an oil-water separator, and finishing the reaction by continuously weighing the reaction water discharged from the oil-water separator until no reaction water is generated;

s2: transferring the reaction material into a distillation kettle, simultaneously starting a vacuum pump unit to carry out reduced pressure distillation to remove n-caprylic acid, collecting condensate liquid when the vacuum degree is-0.096 to-0.1 MPa and the gas phase temperature is 128 to 130 ℃, using the n-caprylic acid condensate liquid in a receiving tank in the next esterification reaction, and obtaining the material in the distillation kettle as a triethylene glycol di-n-caprylate liquid crude product after the distillation is finished;

s3: transferring the triethylene glycol di-n-caprylate liquid crude product into a refining kettle, firstly adding 7% sodium hydroxide solution for neutralization to enable the acid value of the solution to be less than 0.1mgKOH/g, then adding deionized water for two times of water washing operation, standing for layering to discharge water, then heating and raising the temperature, starting a vacuum pump unit, preserving the temperature for 2 hours at the vacuum degree of 5kPa and the temperature of 120 +/-2 ℃ for dehydration, then transferring the triethylene glycol di-n-caprylate liquid crude product into a film evaporator, removing residual water and impurities under the conditions that the temperature is 145 +/-2 ℃ and the vacuum degree is 5Pa, finally separating and purifying through molecular distillation (the distillation temperature is 100 +/-2 ℃ and the vacuum degree is 5Pa), removing residual solvent, pigment and low-boiling point impurities to obtain the triethylene glycol di-n-caprylate finished product, wherein the yield is 99.3%.

In this embodiment, the prepared triethylene glycol di-n-caprylate finished product is subjected to gas chromatography under the gas chromatography conditions, and the specific gas chromatography conditions are as follows: a chromatographic column: chinmadzu gas phase quartz capillary column WondaCap 5, 30m 0.25mm 0.25 μm, column temperature: 220 ℃; the temperature of a sample inlet is 250 ℃; the carrier gas is nitrogen; shunting and injecting samples, wherein the sample injection amount is 1 mu L; the flow rate is 2 mL/min; the tail gas blowing is nitrogen with the flow rate of 45 mL/min; the detector is FID and the detector temperature is 280 ℃ and the results are shown in FIG. 1: the peak-out time of the finished triethylene glycol di-n-caprylate is 3.615 min; meanwhile, the purity of the finished triethylene glycol di-n-caprylate is 99.4% by gas chromatography analysis.

In this example, the obtained triethylene glycol di-n-caprylate finished product (structural formula:) The melting point of the alloy was measured by a melting point tester to be about 4.32 deg.C, as shown in FIG. 2.

Example 2

The embodiment provides a preparation method of triethylene glycol di-n-caprylate, which comprises the following steps:

s1: in heatable equipped stirrer, internal thermometer and moisture10m away from the vessel³Adding triethylene glycol, n-octanoic acid which is 30 mol% excessive based on hydroxyl to be esterified and tetraisobutyl titanate which is 0.02 mol% of the molar amount of the triethylene glycol into a reaction kettle, starting stirring, then starting condensed water and heating to react at 120 ℃, removing formed reaction water on an oil-water separator, continuously weighing the reaction water discharged from the oil-water separator until no reaction water is generated, and finishing the reaction;

s2: transferring the reaction material into a distillation kettle, simultaneously starting a vacuum pump unit to carry out reduced pressure distillation to remove n-caprylic acid, collecting condensate liquid when the vacuum degree is-0.096 to-0.1 MPa and the gas phase temperature is 128 to 130 ℃, using the n-caprylic acid condensate liquid in a receiving tank in the next esterification reaction, and obtaining the material in the distillation kettle as a triethylene glycol di-n-caprylate liquid crude product after the distillation is finished;

s3: transferring the triethylene glycol di-n-caprylate liquid crude product into a refining kettle, firstly adding 7% sodium hydroxide solution for neutralization to enable the acid value of the solution to be less than 0.1mgKOH/g, then adding deionized water for two times of water washing operation, standing for layering to discharge water, then heating and raising the temperature, starting a vacuum pump unit, preserving the temperature for 2 hours at the vacuum degree of 5kPa and the temperature of 120 +/-2 ℃ for dehydration, then transferring the triethylene glycol di-n-caprylate liquid crude product into a film evaporator, removing residual water and impurities under the conditions that the temperature is 145 +/-2 ℃ and the vacuum degree is 5Pa, finally separating and purifying by molecular distillation (the distillation temperature is 100 +/-2 ℃ and the vacuum degree is 5Pa), removing residual solvent, pigment and low-boiling point impurities to obtain the triethylene glycol di-n-caprylate finished product, wherein the yield is 99.2%, and the purity is 99.3% by gas chromatography analysis, the melting point of the finished triethylene glycol di-n-caprylate product is about 4.32 ℃ after being tested by a melting point tester.

Example 3

The embodiment provides a preparation method of triethylene glycol di-n-caprylate, which comprises the following steps:

s1: in a heatable 10m equipped with stirrer, internal thermometer and water separator³The reaction vessel is charged with triethylene glycol, n-octanoic acid in an excess of 25 mol%, based on the hydroxyl groups to be esterified, andtetrabutyl titanate accounting for 0.03mol percent of the molar amount of the triethylene glycol is stirred, then condensed water and heating are started to react at the temperature of 130 ℃, formed reaction water is removed on an oil-water separator, and the reaction is finished by continuously weighing the reaction water discharged by the oil-water separator until no reaction water is generated;

s2: transferring the reaction material into a distillation kettle, simultaneously starting a vacuum pump unit to carry out reduced pressure distillation to remove n-caprylic acid, collecting condensate liquid when the vacuum degree is-0.096 to-0.1 MPa and the gas phase temperature is 128 to 130 ℃, using the n-caprylic acid condensate liquid in a receiving tank in the next esterification reaction, and obtaining the material in the distillation kettle as a triethylene glycol di-n-caprylate liquid crude product after the distillation is finished;

s3: transferring the liquid crude triethylene glycol di-n-caprylate into a refining kettle, firstly adding 7% sodium hydroxide solution for neutralization to ensure that the acid value of the solution is less than 0.1mgKOH/g, then adding deionized water to carry out twice water washing operation, standing and layering to discharge water, then heating and raising temperature, starting a vacuum pump unit, keeping the temperature for 2 hours for dehydration under the vacuum degree of 3kPa and the temperature of 120 +/-2 ℃, then transferring the triethylene glycol di-n-caprylate liquid crude product into a film evaporator, removing residual water and impurities under the conditions that the temperature is 145 +/-2 ℃ and the vacuum degree is 3Pa, finally separating and purifying by molecular distillation (the distillation temperature is 100 +/-2 ℃ and the vacuum degree is 3Pa), removing residual solvent, pigment and low-boiling-point impurities to obtain a triethylene glycol di-n-caprylate finished product, wherein the yield is 99.5%, and the purity is 99.4% by gas chromatography analysis.

In this example, the melting point of the finished triethylene glycol di-n-caprylate product is about 4.32 ℃ as measured by a melting point tester.

In light of the foregoing description of the preferred embodiments according to the present application, it is to be understood that various changes and modifications may be made without departing from the spirit and scope of the invention. The technical scope of the present application is not limited to the contents of the specification, and must be determined according to the scope of the claims.