阅读说明：本技术 1,4-环己烷二甲醇的制备方法 (Process for the preparation of 1, 4-cyclohexanedimethanol ) 是由 廖德超 庄荣仁 陈仲裕 赵崧杰 蔡佳叡 于 2019-05-24 设计创作，主要内容包括：本发明公开一种1,4-环己烷二甲醇的制备方法,此方法通过兼具抽气、排气及搅拌功能的导引气体搅拌器,将输入反应槽内的氢气均匀地分散至反应液中,使得反应液含有高浓度的溶解氢,从而氢化反应时间可缩至最短。再者,此方法所使用的氢化触媒具有活性高、价格低等优点,且在导引气体搅拌器的作用下,氢化触媒的使用量得以降低,使得此方法具有高经济效益。(The invention discloses a method for preparing 1, 4-cyclohexanedimethanol, which uniformly disperses hydrogen input into a reaction tank into a reaction liquid through a guide gas stirrer with the functions of air suction, air exhaust and stirring, so that the reaction liquid contains high-concentration dissolved hydrogen, and the hydrogenation reaction time can be shortened to the shortest. Furthermore, the hydrogenation catalyst used in the method has the advantages of high activity, low price and the like, and the usage amount of the hydrogenation catalyst is reduced under the action of the guide gas stirrer, so that the method has high economic benefit.)

1. A method for producing 1, 4-cyclohexanedimethanol, comprising:

a) providing a hydrogenation reaction tank, wherein a guide gas stirrer with air pumping, air exhausting and stirring functions is arranged in the hydrogenation reaction tank, the guide gas stirrer comprises a hollow rotating shaft and a blade arranged at the tail end of the hollow rotating shaft, and the hollow rotating shaft is provided with an air pumping hole and an air exhausting hole;

b) placing a reaction solution in the hydrogenation reaction tank, wherein the reaction solution comprises cyclohexane-1, 4-diisooctyl phthalate and a solvent;

c) adding a hydrogenation catalyst into the reaction solution, wherein the usage amount of the hydrogenation catalyst is 0.2-15 weight percent of cyclohexane-1, 4-diisooctyl phthalate;

d) feeding hydrogen into the hydrogenation reaction tank to make the hydrogen pressure in the hydrogenation reaction tank be 20-200 bar;

e) starting the guide gas stirrer to make the idle shaft reach a preset rotating speed so as to drive the blade to stir the reaction liquid, wherein the hollow rotating shaft introduces hydrogen from the upper part of the liquid surface of the reaction liquid through the pumping hole of the hollow rotating shaft and then transmits the hydrogen to the reaction liquid through the exhaust hole of the hollow rotating shaft, and the hydrogen in the reaction liquid is stirred by the blade to be in a uniform dispersion state;

f) carrying out hydrogenation reaction, wherein the reaction temperature is 120-260 ℃ and the reaction time is 1-40 hours, so as to hydrogenate the cyclohexane-1, 4-diisooctyl phthalate in the reaction liquid into 1, 4-cyclohexanedimethanol; and

g) cooling the reaction solution to room temperature, and removing the hydrogenation catalyst and the solvent.

2. The method according to claim 1, 4-cyclohexanedimethanol, wherein said solvent is methanol, ethanol, isopropanol, isooctanol, or isononanol.

3. The method according to claim 1, 4-cyclohexanedimethanol, wherein in step c), said hydrogenation catalyst is used in an amount of 0.5 to 10 wt% based on diisooctyl cyclohexane-1, 4-dicarboxylate.

4. The method of claim 3, wherein the hydrogenation catalyst is ruthenium catalyst, palladium catalyst, copper catalyst, rhodium catalyst, nickel catalyst or any combination thereof.

5. The process according to claim 4, wherein the internal hydrogen pressure of the hydrogenation reactor after hydrogen supply in step d) is 50 to 150 bar.

6. The method according to claim 4, wherein the predetermined rotational speed of the hollow shaft and the vane in step e) is 1200-1500 rpm.

7. The process for producing 1, 4-cyclohexanedimethanol according to claim 1, wherein in step f), the hydrogenation is carried out at a reaction temperature of 150 ℃ and 240 ℃.

8. The process according to claim 1, 4-cyclohexanedimethanol, wherein said hydrogenation reaction tank further comprises a heat exchange plate or coil.

Technical Field

The invention relates to a preparation method of 1, 4-cyclohexanedimethanol, in particular to a preparation method of 1, 4-cyclohexanedimethanol based on hydrogenation reaction.

Background

The 1, 4-cyclohexanedimethanol is alicyclic diol with a symmetrical structure, and the resin synthesized by the 1, 4-cyclohexanedimethanol has the characteristics of chemical stability, good transparency, good toughness and the like. The 1, 4-cyclohexanedimethanol is generally produced by a hydrogenation process.

As shown in FIG. 1, a conventional hydrogenation reaction tank 10 for 1, 4-cyclohexanedimethanol production is provided with an impeller stirrer 20, and a rotating shaft 21 of the impeller stirrer 20 is used to rotate a blade 22 provided at the end of the rotating shaft 21 to stir a reaction solution 30. Inserting a hydrogen conduit into the reaction solution 30, and introducing high-pressure hydrogen to force the hydrogen to contact the reaction solution 30, so that the reaction solution 30 is subjected to hydrogenation reaction in the presence of the hydrogen and a catalyst to obtain the 1, 4-cyclohexanedimethanol. The hydrogenation reactor 10 has a low yield of 1, 4-cyclohexanedimethanol after the hydrogenation reaction because the contact efficiency of hydrogen with the reaction solution 30 is low.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a method for preparing 1, 4-cyclohexanedimethanol aiming at the defects of the prior art, wherein the yield of the 1, 4-cyclohexanedimethanol can reach 72.7-76.6%.

In order to solve the above technical problems, one of the technical solutions adopted by the present invention is to provide a method for preparing 1, 4-cyclohexanedimethanol, comprising: step a), providing a hydrogenation reaction tank, wherein a guide gas stirrer with air exhaust, exhaust and stirring functions is arranged in the hydrogenation reaction tank, the guide gas stirrer comprises a hollow rotating shaft and a blade arranged at the tail end of the hollow rotating shaft, and the hollow rotating shaft is provided with an air exhaust hole and an air exhaust hole; step b), placing a reaction liquid into the hydrogenation reaction tank, wherein the reaction liquid comprises cyclohexane-1, 4-dioctyl phthalate and a solvent; c) adding a hydrogenation catalyst into the reaction liquid, wherein the usage amount of the hydrogenation catalyst is 0.2-15 weight percent of cyclohexane-1, 4-diisooctyl phthalate; step d), hydrogen is input into the hydrogenation reaction tank, so that the pressure of the hydrogen in the hydrogenation reaction tank is 20-200 bar; step e), starting the guide gas stirrer to enable the idle shaft to reach a preset rotating speed so as to drive the blade to stir the reaction liquid, wherein the hollow rotating shaft introduces hydrogen from the upper part of the liquid level of the reaction liquid through the pumping hole of the hollow rotating shaft and then transmits the hydrogen to the reaction liquid through the exhaust hole of the hollow rotating shaft, and the hydrogen in the reaction liquid is stirred by the blade to be in a uniform dispersion state; step f), carrying out hydrogenation reaction, wherein the reaction temperature is 120-260 ℃ and the reaction time is 1-40 hours, so as to hydrogenate the cyclohexane-1, 4-diisooctyl phthalate in the reaction liquid into 1, 4-cyclohexanedimethanol; and step g), cooling the reaction solution to room temperature, and removing the hydrogenation catalyst and the solvent.

One of the advantages of the present invention is that the method for preparing 1, 4-cyclohexanedimethanol provided by the present invention uses a guiding gas stirrer with pumping, exhausting and stirring functions in a hydrogenation reactor, so as to achieve the following effects: 1. the contact efficiency of hydrogen and the reaction liquid is improved; 2. the reaction liquid for hydrogenation contains high-concentration dissolved hydrogen, so that the hydrogenation catalyst has extremely high activity and rapid hydrogenation reaction rate; 3. the hydrogenation reaction can obtain 1, 4-cyclohexanedimethanol with high yield, and the method is economic.

For a better understanding of the features and technical content of the present invention, reference should be made to the following detailed description of the invention and accompanying drawings, which are provided for purposes of illustration and description only and are not intended to limit the invention.

Drawings

FIG. 1 is a schematic view of a conventional hydrogenation reactor.

FIG. 2 is a flow chart of a process for the preparation of 1, 4-cyclohexanedimethanol according to the invention.

FIG. 3 is a schematic view of the structure of a hydrogenation reaction tank according to the present invention.

Detailed Description

The following is a description of the embodiments of the "process for producing 1, 4-cyclohexanedimethanol" disclosed in the present invention by specific examples, and those skilled in the art can understand the advantages and effects of the present invention from the disclosure in the present specification. The invention is capable of other and different embodiments and its several details are capable of modification and various other changes, which can be made in various details within the specification and without departing from the spirit and scope of the invention. The drawings of the present invention are for illustrative purposes only and are not intended to be drawn to scale. The following embodiments will further explain the related art of the present invention in detail, but the disclosure is not intended to limit the scope of the present invention.

It will be understood that, although the terms "first," "second," "third," etc. may be used herein to describe various components or signals, these components or signals should not be limited by these terms. These terms are used primarily to distinguish one element from another element or from one signal to another signal. In addition, the term "or" as used herein should be taken to include any one or combination of more of the associated listed items as the case may be.

Referring to FIG. 2, the present invention provides a method for preparing 1, 4-cyclohexanedimethanol using diisooctyl cyclohexane-1, 4-dicarboxylate to prepare 1, 4-cyclohexanedimethanol; the preparation method mainly comprises the following steps: step S1, providing a hydrogenation reaction tank, wherein a guide gas stirrer is arranged in the hydrogenation reaction tank; step S2, placing a reaction solution in a hydrogenation reaction tank; step S3, adding a hydrogenation catalyst into the reaction solution; step S4, inputting hydrogen into a hydrogenation reaction tank; and step S5, carrying out hydrogenation reaction.

Referring to FIG. 3, a hydrogenation reactor 40 provided in step 1 is used to hydrogenate diisooctyl cyclohexane-1, 4-dicarboxylate to produce 1, 4-cyclohexanedimethanol. The hydrogenation reaction tank 40 is provided therein with a guide gas stirrer 50, and the guide gas stirrer 50 has the functions of pumping, exhausting and stirring, so as to promote the contact efficiency of the hydrogen gas with the reaction solution 30 and to improve the yield of 1, 4-cyclohexanedimethanol.

Further, the hydrogenation reaction tank 40 may be a cylindrical pressure-resistant vessel, and the ratio of the height to the diameter thereof is preferably in the range of 0.4 to 3. In addition to the guiding gas stirrer 50, a heating exchange plate or a coil (not shown) may be additionally installed in the hydrogenation reaction tank 40 for removing the heat released from the hydrogenation reaction in time to avoid heat accumulation.

The guiding gas stirrer 50 comprises a hollow rotating shaft 51 and a blade 52 arranged at the tail end of the hollow rotating shaft 51; an air flow passage 53 is formed inside the hollow rotating shaft 51 for supplying hydrogen gas; the upper end of the hollow rotating shaft 51 is provided with a plurality of air extraction holes 54 communicated with the airflow channel 53, and when in use, the air extraction holes 54 are positioned above the liquid level 31 of the cyclohexane-1, 4-diisooctyl phthalate reaction liquid 30 and are used for guiding hydrogen into the airflow channel 53; the hollow rotating shaft 51 is provided at the lower end thereof with a plurality of exhaust holes 55 communicating with the gas flow passage 53 for discharging the hydrogen gas introduced into the gas flow passage 53. The blades 52 of the guide gas agitator 50 may be flat-plate-shaped blades, curved-shaped blades, or concave-shaped blades.

In step S2, the reaction solution 30 may be poured into the hydrogenation reaction tank 40, wherein the reaction solution 30 includes cyclohexane-1, 4-dicarboxylic acid diisooctyl ester and a solvent. The solvent is used for diluting cyclohexane-1, 4-dicarboxylic acid diisooctyl ester, and the solvent may be methanol, ethanol, isopropanol, isooctanol, or isononyl alcohol, but is not limited thereto. These solvents do not deteriorate the activity of the hydrogenation catalyst and do not react with diisooctyl cyclohexane-1, 4-dicarboxylate to produce unwanted by-products. When the amount of the diluting solvent used is 1 to 3 times that of diisooctyl cyclohexane-1, 4-dicarboxylate, the hydrogenation rate can be accelerated.

In step S3, the hydrogenation catalyst is used to promote the hydrogenation reaction of cyclohexane-1, 4-dioctyl phthalate, and the hydrogenation catalyst can be a heterogeneous catalyst, which can be ruthenium catalyst, palladium catalyst, copper catalyst, rhodium catalyst, nickel catalyst or any combination thereof. If considering the hydrogenation rate and cost, the amount of the hydrogenation catalyst used may be 0.2 to 15% by weight, preferably 0.5 to 10% by weight, based on the diisooctyl cyclohexane-1, 4-dicarboxylate.

In step S4, the internal hydrogen pressure of the hydrogenation reaction tank 40 after the hydrogen gas is supplied may be 20 to 200 bar (bar), preferably 50 to 150 bar. In step S5, the hollow shaft 51 of the guiding gas agitator 50 reaches a predetermined rotation speed to drive the blades 51 to agitate the reaction solution 30; the predetermined rotation speed may be 1200 and 1500rpm, preferably 1400 rpm. At this time, the hydrogen gas above the liquid surface 31 of the reaction solution 30 is pumped and guided into the gas flow path 53 through the pumping hole 54, and then discharged into the reaction solution 30 through the exhaust hole 55, and is uniformly dispersed by the stirring action of the blade 52. Therefore, the contact efficiency of hydrogen and the reaction solution 30 can be improved, so that the reaction solution 30 can contain high-concentration dissolved hydrogen, and the hydrogenation catalyst has extremely high activity and rapid hydrogenation reaction rate.

In step S6, the reaction temperature of the hydrogenation reaction may be 260 ℃ and preferably 150 ℃ and 240 ℃ and the reaction time may be 1 to 40 hours, so as to hydrogenate the cyclohexane-1, 4-dicarboxylic acid diisooctyl ester in the reaction solution 30 into 1, 4-cyclohexanedimethanol. It is to be noted that when the hydrogenation reaction tank 40 is provided therein with the guide gas agitator 50 and the heat exchange plates or coils, the yield of 1, 4-cyclohexanedimethanol can be improved; this is because the efficiency of contact between the hydrogen gas in the hydrogenation reaction tank 40 and the reaction solution 30 is improved, and the heat generated by the hydrogenation reaction can be discharged in time.

After the hydrogenation reaction is finished, the reaction solution 30 is cooled to room temperature, and the catalyst is filtered out and the solvent is removed, so that the recovered product is obtained. The composition of the recovered product comprises 25-50 weight percent of 1, 4-cyclohexanedimethanol, 50-75 weight percent of solvent and a small amount of impurities, wherein the yield of the 1, 4-cyclohexanedimethanol can reach 72.7-76.6%.

The present invention will be described more specifically with reference to the following examples and comparative examples, which are intended to illustrate the present invention and are not intended to limit the scope of the present invention.