Method and device for preparing 2, 2, 4, 4-tetramethyl-1, 3-cyclobutanediol without solvent

Abstract

The invention provides a solvent-free method for preparing 2, 2, 4, 4-tetramethyl-1, 3-cyclobutanediol, which comprises the following steps: in an inert gas atmosphere, taking 2, 2, 4, 4-tetramethyl-1, 3-cyclobutanedione and hydrogen as raw materials, introducing the raw materials into a fixed bed reactor containing a metal catalyst, and carrying out a catalytic hydrogenation reaction to prepare the 2, 2, 4, 4-tetramethyl-1, 3-cyclobutanediol. According to the method, a sublimation method is adopted, gaseous molecules of gas-phase 2, 2, 4, 4-tetramethyl-1, 3-cyclobutanedione are more easily and uniformly mixed with hydrogen, collision among the gaseous molecules promotes the reaction, and the purity of the product is not less than 99%; in addition, no intermolecular effect of a solvent exists, so that a cis structure which is difficult to generate is more easily generated under the action of a catalyst, and the proportion of cis-2, 2, 4, 4-tetramethyl-1, 3-cyclobutanediol in the product reaches 70% or above; according to the present invention, the method has characteristics of mild reaction conditions, no addition of other solvents during the reaction process, high reaction degree and simple purification, and the 2, 2, 4, 4-tetramethyl-1, 3-cyclobutanediol obtained through hydrogenation can achieve the standard after one-time water washing dispersion, such that the method is the green and efficient 2, 2, 4, 4-tetramethyl-1, 3-cyclobutanediol production technology.

Description

Technical Field

[0001] The invention belongs to the technical field of organic chemistry, and particularly relates to a method and a preparation device for preparing 2,2,4,4-tetramethyl-1,3-cyclobutanediol without solvent. Background Art

[0002] 2,2,4,4-Tetramethyl-1,3-cyclobutanediol (CBDO) is an aliphatic diol and a precursor for the production of various polymers including modified polycarbonate. CBDO has two isomers of cis and trans structures according to the different spatial positions of the hydroxyl groups. The C4 ring of cis-CBDO is non-planar, and the crystal has a dihedral angle of 17.5°; the dihedral angle of trans-CBDO is 0°. CBDO has a symmetrical structure, the C4 ring is very stable, and the two terminal hydroxyl groups are not easy to cyclize, especially cis-CBDO has better effect.

[0003] 2,2,4,4-Tetramethyl-1,3-cyclobutanediol is an important raw material for the synthesis of high-performance polyesters. Copolyesters synthesized with CBDO as raw material have the characteristics of high melt viscosity, high glass transition temperature, and easy processing. Due to the above chemical properties, the main application areas of CBDO are as follows: First, the preparation of polyester materials without bisphenol A, such as the manufacture of components for baby products and medical devices; second, the preparation of polyester materials that are easy to process into films and sheets, such as the manufacture of flat decorative panels for washing machines, flat touch panels on refrigerators, interior decoration and dashboards of automobiles, display screens and keyboards of electronic devices, etc.; third, as an antibacterial agent, it is used in products that contain water or can absorb moisture from the environment in the fields of water-based coatings, personal care, medical and household care.

[0004] The existing hydrogenation process for preparing CBDO mainly uses an organic solvent to dissolve 2,2,4,4-tetramethyl-1,3-cyclobutanedione (TMCD), and then obtains the target product CBDO by hydrogenation reduction under the action of different catalysts. This method has problems such as low utilization rate, low efficiency, organic solvent pollution, ring opening during solvent hydrogenation, and uncontrollable ratio of cis-trans CBDO.

[0005] To solve the above problems, we have developed a solvent-free hydrogenation process with simple steps, high efficiency and controllable ratio of cis-trans 2,2,4,4-tetramethyl-1,3-cyclobutanediol to prepare 2,2,4,4-tetramethyl-1,3-cyclobutanediol, which is an urgent problem to be solved in this field. Summary of the invention

[0006] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for preparing 2,2,4,4-tetramethyl-1,3-cyclobutanediol without solvent, which has simple steps, high efficiency and high cis-trans ratio. The present invention adopts a sublimation method, does not add other solvents during the reaction process, has a high reaction degree, is simple to purify, and the proportion of cis-2,2,4,4-tetramethyl-1,3-cyclobutanediol reaches more than 70%, and has better performance.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] The first object of the present invention is to provide a method for preparing 2,2,4,4-tetramethyl-1,3-cyclobutanediol without solvent. Under an inert gas atmosphere, 2,2,4,4-tetramethyl-1,3-cyclobutanedione and hydrogen are used as raw materials and introduced into a fixed bed reactor containing a metal catalyst for catalytic hydrogenation reaction to prepare 2,2,4,4-tetramethyl-1,3-cyclobutanediol.

[0009] Specifically, the 2,2,4,4-tetramethyl-1,3-cyclobutanedione is added into a sublimation reactor, and the temperature is raised to a temperature within the range of ±10° C. of the melting point of the 2,2,4,4-tetramethyl-1,3-cyclobutanedione to obtain gas-phase 2,2,4,4-tetramethyl-1,3-cyclobutanedione.

[0010] Specifically, the metal catalyst is at least one selected from a platinum-carbon catalyst and a palladium-carbon catalyst;

[0011] Preferably, the feed mass ratio of the 2,2,4,4-tetramethyl-1,3-cyclobutanedione to the metal catalyst is 1:(0.1-1.0).

[0012] Specifically, the temperature of the catalytic hydrogenation reaction is 140-160° C., and the time of the catalytic hydrogenation reaction is 3-5 hours.

[0013] Specifically, the flux mass ratio of the gas phase 2,2,4,4-tetramethyl-1,3-cyclobutanedione and hydrogen is 1:(0.08-0.2).

[0014] Specifically, the method further includes post-treatment, wherein after the catalytic hydrogenation reaction, a liquid containing 2,2,4,4-tetramethyl-1,3-cyclobutanediol is obtained, the liquid is introduced into pure water for stirring and dispersion, and the 2,2,4,4-tetramethyl-1,3-cyclobutanediol is obtained by filtering and drying.

[0015] Specifically, after replacing the sublimation kettle with inert gas at least three times, the 2,2,4,4-tetramethyl-1,3-cyclobutanedione is added to the sublimation kettle, and then the sublimation kettle is replaced with inert gas at least three times; after replacing the fixed bed reactor with inert gas and hydrogen respectively at least three times, the fixed bed reactor and the sublimation kettle are heated in turn under an atmosphere of continuous hydrogen supply to carry out catalytic hydrogenation reaction.

[0016] Specifically, the purity of the product is ≥99%, and the proportion of cis-2,2,4,4-tetramethyl-1,3-cyclobutanediol in the product is ≥70%.

[0017] Cis-trans isomers are two atoms or groups located on different sides of a double bond, the cis isomers are on the same side, and the trans isomers are on opposite sides. The cis isomers contain higher molecular energy, and the conditions that are conducive to the production of cis isomers are: 1. high temperature, 2. ultraviolet light, and 3. catalyst. The high temperature reaction and the platinum-carbon catalyst and palladium-carbon catalyst used in the present invention are all conducive to the conversion of cis isomers.

[0018] The second object of the present invention is to provide a preparation device used in the above method, comprising a sublimation kettle, a fixed bed reactor connected to the sublimation kettle, a hydrogen delivery pipeline arranged between the sublimation kettle and the fixed bed reactor, and a dispersion kettle connected to the discharge port of the fixed bed reactor.

[0019] Specifically, the device further comprises a weighing module arranged on the sublimation kettle, a flow meter and a hydrogen regulating valve arranged on the hydrogen delivery pipeline, and the weighing module is interlocked with the flow meter. The interlocking mentioned in the present invention is an electrical connection.

[0020] A weighing module is added under the sublimation kettle, and the weight loss of the sublimation kettle is monitored to calculate the mass of 2,2,4,4-tetramethyl-1,3-cyclobutanedione entering the fixed bed reactor. The hydrogen flow rate is adjusted by adjusting the opening of the hydrogen regulating valve to make the mass ratio of hydrogen to 2,2,4,4-tetramethyl-1,3-cyclobutanedione controllable, thereby ensuring that 2,2,4,4-tetramethyl-1,3-cyclobutanedione can react with sufficient hydrogen.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The invention provides a method for preparing 2,2,4,4-tetramethyl-1,3-cyclobutanediol without solvent. The method adopts a sublimation method, and gaseous molecules of gas-phase 2,2,4,4-tetramethyl-1,3-cyclobutanedione are more easily mixed with hydrogen, and collision between gaseous molecules promotes the reaction. The purity of the product of the invention is not less than 99%; and because there is no intermolecular effect of the solvent, it is easier to generate a cis structure that is difficult to generate under the action of a catalyst, so that the cis-2,2,4,4-tetramethyl-1,3-cyclobutanediol in the product The ratio reaches more than 70%; no other solvents are added during the reaction, the reaction degree is high, and the purification is simple. It not only avoids the problems of low efficiency and complex process caused by the existing process solvent occupying more hydrogenation space, and avoids the problem of insufficient reaction caused by the solid phase reaction of the existing process and thus causing many by-products. In addition, the 2,2,4,4-tetramethyl-1,3-cyclobutanediol obtained by hydrogenation can meet the standards after one water washing and dispersion. It is a green and efficient 2,2,4,4-tetramethyl-1,3-cyclobutanediol production technology that can be promoted industrially. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Attached Figure 1 It is a schematic diagram of the preparation device of the present invention;

[0024] Among them, 1-sublimation kettle; 2-fixed bed reactor; 21-discharge port; 3-dispersion kettle; 4-weighing module; 5-flow meter; 6-hydrogen regulating valve; 7-hydrogen delivery pipeline. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0026] The present invention provides a preparation device, as shown in the attached Figure 1 As shown, the preparation device includes a sublimation kettle 1, a fixed bed reactor 2 connected to the sublimation kettle 1, a hydrogen delivery pipeline 7 arranged between the sublimation kettle 1 and the fixed bed reactor 2, and a dispersion kettle 3 connected to the discharge port 21 of the fixed bed reactor 2. In order to accurately control the quality, the preparation device also includes a weighing module 4 arranged on the sublimation kettle 1, a flow meter 5 and a hydrogen regulating valve 6 arranged on the hydrogen delivery pipeline 7, and the weighing module 4 is interlocked with the flow meter 5.

[0027] Example 1

[0028] This embodiment provides a method for preparing 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO) without solvent. The specific preparation method is as follows:

[0029] After replacing the sublimation kettle with nitrogen three times, 500g of 2,2,4,4-tetramethyl-1,3-cyclobutanedione (TMCD) solid was added to the sublimation kettle, and the sublimation kettle was replaced with nitrogen three times; after replacing the fixed bed reactor with nitrogen and hydrogen three times respectively, the fixed bed reactor was heated to 140°C and the sublimation kettle was heated to 110°C under a continuous hydrogen supply atmosphere, and the gaseous TMCD and hydrogen simultaneously entered the fixed bed reactor loaded with 500g of platinum carbon catalyst, and the unit flow rate of hydrogen was converted into a unit mass of 0.12 times the weight loss of TMCD per unit time, and the catalytic hydrogenation reaction was carried out for 4h, and the CBDO liquid obtained at the discharge port of the fixed bed reactor was passed into a dispersion kettle filled with pure water, stirred and dispersed, filtered and dried to obtain a white crystalline solid, i.e., 504gCBDO, the content of which was 99.5% by GC detection, the content of cis-CBDO was 72%, and the content of trans-CBDO was 27.5%.

[0030] Example 2

[0031] This embodiment provides a method for preparing 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO) without solvent, which is basically the same as Example 1, except that the temperature of the fixed bed reactor is changed to 150° C., and after post-treatment, 504 g of CBDO is obtained. The content, i.e., the purity, is 99.5% as detected by GC, the content of cis-CBDO is 74.5%, and the content of trans-CBDO is 25%.

[0032] Example 3

[0033] This embodiment provides a method for preparing 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO) without solvent, which is basically the same as Example 1, except that the temperature of the fixed bed reactor is changed to 160° C., and after post-treatment, 506 g of CBDO is obtained, and the content is 99.7% detected by GC, the content of cis-CBDO is 82.2%, and the content of trans-CBDO is 17.5%.

[0034] Example 4

[0035] This embodiment provides a method for preparing 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO) without solvent, which is basically the same as Example 1, except that the hydrogenation reaction time is changed to 3 hours. After post-treatment, 502g of CBDO is obtained, and the content, i.e., the purity, is 99.3% as determined by GC, the content of cis-CBDO is 72.3%, and the content of trans-CBDO is 27%.

[0036] Example 5

[0037] This embodiment provides a method for preparing 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO) without solvent, which is basically the same as Example 1, except that the hydrogenation reaction time is changed to 5 hours. After post-treatment, 507g of CBDO is obtained, and the content, i.e., the purity, is 99.7% as detected by GC, the content of cis-CBDO is 72.2%, and the content of trans-CBDO is 27.5%.

[0038] Example 6

[0039] This embodiment provides a method for preparing 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO) without solvent, which is basically the same as Example 1, except that 500g of palladium carbon catalyst is used as the catalyst. After post-treatment, 502g of CBDO is obtained, and the content, i.e., the purity, is 99.6% as determined by GC, the content of cis-CBDO is 70.3%, and the content of trans-CBDO is 29.3%.

[0040] Example 7

[0041] This embodiment provides a method for preparing 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO) without solvent, which is basically the same as Example 1, except that 250g of platinum carbon catalyst and 250g of palladium carbon catalyst are mixed for the catalyst. After post-treatment, 502g of CBDO is obtained, and the content, i.e., the purity, is 99.5% as detected by GC, the content of cis-CBDO is 73.4%, and the content of trans-CBDO is 26.1%.

[0042] Example 8

[0043] This embodiment provides a method for preparing 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO) without solvent, which is basically the same as Example 1, except that a catalytic hydrogenation reaction is carried out under an atmosphere of continuous supply of hydrogen (the unit flow rate of hydrogen converted into unit mass is 0.08 times the weight loss of TMCD per unit time), and after post-treatment, 503 g of CBDO is obtained. The content, i.e., the purity, is 99.0% as determined by GC, the content of cis-CBDO is 68%, and the content of trans-CBDO is 31%.

[0044] Example 9

[0045] The present embodiment provides a method for preparing 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO) without solvent, which is basically the same as Example 1, except that a catalytic hydrogenation reaction is carried out under an atmosphere of continuous supply of hydrogen (the unit time flow rate of hydrogen converted into unit time mass is 0.20 times the weight loss of TMCD per unit time), and after post-treatment, 504g CBDO is obtained. The content, i.e., purity, is 99.6% as determined by GC, the content of cis-CBDO is 74.3%, and the content of trans-CBDO is 25.3%.

[0046] Comparative Example 1

[0047] This comparative example provides a method for preparing 2,2,4,4-tetramethyl-1,3-cyclobutanediol in a kettle without solvent, comprising the following steps: first, TMCD is added to a hydrogenation kettle in a molten state, a catalyst and hydrogen are added to perform a catalytic hydrogenation reaction, and after the reaction is completed, the material is transferred out for refining treatment, the product purity is 92%, and the mass ratio of cis-CBDO in the obtained product is 56%. This method also has the following problems: it is difficult to filter the catalyst when discharging the material and the product is not filtered cleanly. When the catalyst is cleaned after the filter is cooled, the catalyst and the material are mixed together, which makes separation difficult; hydrogenation in a liquid phase state causes a low cis-trans ratio due to the molecular effect between molecules.

[0048] The invention provides a method for preparing 2,2,4,4-tetramethyl-1,3-cyclobutanediol without solvent. The method adopts a sublimation method, and gaseous molecules of gas-phase 2,2,4,4-tetramethyl-1,3-cyclobutanedione are more easily mixed with hydrogen, and collision between gaseous molecules promotes the reaction. The purity of the product of the invention is not less than 99%; and because there is no intermolecular effect of the solvent, it is easier to generate a cis structure that is difficult to generate under the action of a catalyst, so that the cis-2,2,4,4-tetramethyl-1,3-cyclobutanediol in the product The ratio reaches more than 70%; no other solvents are added during the reaction, the reaction degree is high, and the purification is simple. It not only avoids the problems of low efficiency and complex process caused by the existing process solvent occupying more hydrogenation space, and avoids the problem of insufficient reaction caused by the solid phase reaction of the existing process and thus causing many by-products. In addition, the 2,2,4,4-tetramethyl-1,3-cyclobutanediol obtained by hydrogenation can meet the standards after one water washing and dispersion. It is a green and efficient 2,2,4,4-tetramethyl-1,3-cyclobutanediol production technology that can be promoted industrially.

[0049] The applicant declares that the present invention illustrates a method and a preparation device for 2,2,4,4-tetramethyl-1,3-cyclobutanediol of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing 2,2,4,4-tetramethyl-1,3-cyclobutanediol without solvent, characterized in that: Under an inert gas atmosphere, 2,2,4,4-tetramethyl-1,3-cyclobutanedione and hydrogen are used as raw materials and introduced into a fixed bed reactor containing a metal catalyst for catalytic hydrogenation reaction to prepare 2,2,4,4-tetramethyl-1,3-cyclobutanediol.

2. The method for preparing 2,2,4,4-tetramethyl-1,3-cyclobutanediol without solvent according to claim 1, characterized in that: The 2,2,4,4-tetramethyl-1,3-cyclobutanedione is added into a sublimation reactor and heated to 104-126° C. to obtain gaseous 2,2,4,4-tetramethyl-1,3-cyclobutanedione.

3. The method for preparing 2,2,4,4-tetramethyl-1,3-cyclobutanediol without solvent according to any one of claims 1 or 2, characterized in that: The metal catalyst is at least one selected from a platinum-carbon catalyst and a palladium-carbon catalyst; Preferably, the feed mass ratio of the 2,2,4,4-tetramethyl-1,3-cyclobutanedione to the metal catalyst is 1:(0.1-1.0).

4. The method for preparing 2,2,4,4-tetramethyl-1,3-cyclobutanediol without solvent according to any one of claims 1 to 3, characterized in that: The temperature of the catalytic hydrogenation reaction is 140-160° C., and the time of the catalytic hydrogenation reaction is 3-5 hours.

5. The method for preparing 2,2,4,4-tetramethyl-1,3-cyclobutanediol without solvent according to any one of claims 1 to 4, characterized in that: The flux mass ratio of the gas phase 2,2,4,4-tetramethyl-1,3-cyclobutanedione and hydrogen is 1:(0.08-0.2).

6. The method for preparing 2,2,4,4-tetramethyl-1,3-cyclobutanediol without solvent according to any one of claims 1 to 5, characterized in that: The method further comprises post-treatment, wherein after the catalytic hydrogenation reaction, a liquid containing 2,2,4,4-tetramethyl-1,3-cyclobutanediol is obtained, the liquid is introduced into pure water for stirring and dispersion, and the 2,2,4,4-tetramethyl-1,3-cyclobutanediol is obtained by filtering and drying.

7. The method for preparing 2,2,4,4-tetramethyl-1,3-cyclobutanediol without solvent according to any one of claims 2 to 6, characterized in that: After replacing the sublimation kettle with inert gas at least three times, the 2,2,4,4-tetramethyl-1,3-cyclobutanedione is added to the sublimation kettle, and then the sublimation kettle is replaced with inert gas at least three times; after replacing the fixed bed reactor with inert gas and hydrogen respectively at least three times, the fixed bed reactor and the sublimation kettle are heated in turn under the atmosphere of continuous hydrogen supply to carry out catalytic hydrogenation reaction.

8. The method for preparing 2,2,4,4-tetramethyl-1,3-cyclobutanediol without solvent according to any one of claims 1 to 7, characterized in that: The purity of the product is ≥99%, and the proportion of cis-2,2,4,4-tetramethyl-1,3-cyclobutanediol in the product is ≥70%.

9. A preparation device used in the method according to any one of claims 1 to 8, characterized in that: The invention comprises a sublimation kettle, a fixed bed reactor connected with the sublimation kettle, a hydrogen delivery pipeline arranged between the sublimation kettle and the fixed bed reactor, and a dispersion kettle connected with the discharge port of the fixed bed reactor.

10. The preparation device according to claim 9, characterized in that: The device further comprises a weighing module arranged on the sublimation kettle, a flow meter and a hydrogen regulating valve arranged on the hydrogen delivery pipeline, and the weighing module is interlocked with the flow meter.

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