A catalyst for hydrogenating methyl 3-hydroxypropionate to 1,3-propylene glycol and a preparation method thereof

Abstract

The present invention discloses a catalyst for hydrogenating methyl 3-hydroxypropionate to produce 1,3-propylene glycol, and a preparation method thereof. The catalyst is prepared using a sol-gel method and comprises the following components: (a) a main component, CuO; (b) an electron-enhancing agent, gallium nitride; and (c) a support and a pore-enlarging agent, SiO2. In the catalyst, the electron-enhancing agent, gallium nitride, reacts with the main component, CuO, to form active sites that enhance the conversion of 1,3-propylene glycol. Therefore, this catalyst exhibits high activity and product selectivity when used to hydrogenate methyl 3-hydroxypropionate to produce 1,3-propylene glycol, addressing the low activity and low selectivity of the main product, 1,3-propylene glycol, associated with existing catalysts of this type.

Description

Technical Field

[0001] The invention belongs to the field of catalyst preparation, and particularly relates to a catalyst for preparing 1,3-propylene glycol by hydrogenating methyl 3-hydroxypropionate and a preparation method thereof. Background Art

[0002] 1,3-Propanediol (1,3-PDO) is a colorless, odorless, transparent liquid that is miscible in water, alcohols, and various organic solvents, and exhibits the typical properties of both alcohols and diols. As an important chemical raw material, 1,3-PDO is not only used in the synthesis of detergents, preservatives, emulsifiers, and plasticizers, but is also used in the food, cosmetics, and pharmaceutical industries. However, its primary application is as a polymer monomer in the synthesis of high-performance polymer materials. For example, it can replace ethylene glycol and butanediol in the production of polyol polyesters, which are then used to manufacture the high-performance polyester fiber polytrimethylene terephthalate (PTT), which is then used in the clothing, carpet, electronics, and automotive markets. As PTT fiber production technology matures and costs continue to decrease, PTT can gradually replace 5-10% of traditional polyester fibers at a reasonable price difference, showing a promising market prospect. 1,3-PDO is a key raw material in the synthesis of PTT and is irreplaceable.

[0003] Currently, the methods for preparing 1,3-propylene glycol are mainly divided into two types: chemical synthesis and biological fermentation. Among them, the methods for preparing 1,3-propylene glycol through chemical synthesis include the EO method and the acrolein hydration method. The EO method, also known as the ethylene oxide carbonyl synthesis method, is mainly divided into two process routes: ethylene oxide hydroformylation and ethylene oxide hydroesterification. Among them, the ethylene oxide hydroesterification method has low raw material costs and is easy to scale up to achieve large-scale production. In addition, the intermediate 3-hydroxypropionic acid methyl ester in this method is more stable than the intermediate 3-hydroxypropionaldehyde in the ethylene oxide hydroformylation method. Because 3-hydroxypropionic acid methyl ester contains a β-hydroxy group, it is easier to remove than ester hydrogenation, creating more and more suitable ester hydrogenation active sites, which will greatly improve the selectivity of the main product 1,3-propylene glycol.

[0004] In recent years, copper-based catalysts have become the preferred catalyst for the hydrogenation of methyl 3-hydroxypropionate to 1,3-propylene glycol due to their low production cost and, when combined with other active additives, their ability to achieve high activity, high selectivity, mild reaction conditions, and excellent toxicity resistance. Patent CN 101993352A reports a multi-metal oxide catalyst prepared by coprecipitation using Cu, Mn, and Zr oxides as active components. This catalyst exhibits a uniform distribution of active components, suppressing dehydration side reactions and improving product selectivity, resulting in excellent reactivity and stability. Patent CN 1911507A utilizes an organic amine as a complexing agent, adding fatty alcohol orthosilicate and aluminum fatty alcohol as catalyst support precursors, and then adding a gelling agent and heating to form a sol-gel to produce a low-loading copper-based single-component catalyst. This method effectively improves the catalyst's sintering resistance and service life, but the organic amine reagent used has a pungent odor, making it unfriendly to humans and the environment, and its catalytic activity remains to be improved. Patent CN 103721734A reports that using copper oxide as the main active ingredient, adding active additives such as manganese oxide, molybdenum oxide, and phosphorus pentoxide, and using silicon dioxide as a catalyst carrier, it is possible to hydrogenate methyl 3-hydroxypropionate to produce 1,3-propylene glycol at high concentrations, significantly improving product conversion and selectivity. Summary of the Invention

[0005] In response to the problems of low activity, numerous side reactions and low selectivity of 1,3-propylene glycol in existing catalysts, the present invention provides a catalyst for hydrogenating methyl 3-hydroxypropionate to produce 1,3-propylene glycol and a preparation method thereof.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A catalyst for hydrogenating methyl 3-hydroxypropionate to 1,3-propylene glycol, comprising the following components:

[0008] (a) Main component CuO;

[0009] (b) electron-aiding agent gallium nitride;

[0010] (c) Carrier and pore-enlarging agent SiO2.

[0011] Furthermore, based on the sum of weight percentages being 100%, the contents of the components are: main component 30%, electronic auxiliary agent 2-5%, SiO2 65-68%.

[0012] Furthermore, the crystal structure of the gallium nitride is a wurtzite structure or a zinc blende structure.

[0013] The preparation method of the catalyst for hydrogenating methyl 3-hydroxypropionate to 1,3-propylene glycol comprises the following steps:

[0014] (1) Dissolve the CuO precursor in deionized water and continue stirring until the solution becomes transparent;

[0015] (2) Add gallium nitride powder to the solution obtained in step (1), disperse it ultrasonically, and then stir it thoroughly for 2 hours;

[0016] (3) Slowly add the alcohol solution of tetraethyl orthosilicate to the solution obtained in step (2), stir thoroughly for 1 hour, and then transfer to a 50°C water bath to react for 3 hours to form a sol-gel;

[0017] (4) aging the sol-gel obtained in step (3) at room temperature for 6-24 hours, filtering, and washing until the residual liquid is neutral;

[0018] (5) drying the gel obtained in step (4) at 80-150°C for 12-36 hours;

[0019] (6) calcining the solid obtained in step (5) at 400-600° C. for 4-24 h to obtain the catalyst.

[0020] Furthermore, the precursor of CuO in step (1) is one or more of copper nitrate, copper sulfate, copper acetate, copper acetylacetonate, and copper chloride, preferably copper nitrate.

[0021] Furthermore, the ultrasonic dispersion time in step (2) is 15-60 minutes.

[0022] Furthermore, in the alcohol solution of tetraethyl orthosilicate in step (3), the molar ratio of tetraethyl orthosilicate to anhydrous ethanol is 1:4.

[0023] The obtained catalyst can be used for hydrogenation of methyl 3-hydroxypropionate to 1,3-propylene glycol. The specific operation is as follows: the catalyst loading amount is 10.0 ml. Before feeding, the catalyst is reduced with hydrogen to make the active component exist in the form of a single substance. The reduction conditions are: temperature 200-450 ° C, pressure 0.1-8.0 MPa, hydrogen flow rate 10-200 ml / min, time 0.5-36 h. During the reaction, methyl 3-hydroxypropionate is diluted with methanol, the mass concentration of methyl 3-hydroxypropionate is 5-20%, the temperature is 140-200 ° C, the pressure is 3-8 MPa, and the raw material space velocity is 0.01-3.0 h -1 , hydrogen ester ratio 200-600.

[0024] The significant advantages of the present invention are:

[0025] The present invention adopts the sol-gel method to form a composite copper-based hydrogenation catalyst by combining the main catalyst CuO, the electron auxiliary agent gallium nitride and SiO2. The gallium nitride is used as the electron auxiliary agent to stabilize the Cu generated in the reaction process. + / Cu 0Active sites promote the adsorption of ester groups in methyl 3-hydroxypropionate, thereby improving catalyst activity and selectivity for 1,3-propylene glycol. DETAILED DESCRIPTION

[0026] A catalyst for hydrogenating methyl 3-hydroxypropionate to produce 1,3-propylene glycol comprises, based on a total weight percentage of 100%, 30% of a main component of CuO, 2-5% of an electron auxiliary agent of gallium nitride, and 65-68% of a carrier and pore-enlarging agent of SiO2.

[0027] The preparation method of the catalyst for hydrogenating 3-hydroxypropionate to 1,3-propylene glycol comprises the following steps:

[0028] (1) Dissolve the CuO precursor in deionized water and continue stirring until the solution becomes transparent;

[0029] (2) Add gallium nitride powder to the solution obtained in step (1), disperse it by ultrasonication for 15-60 minutes, and then stir it thoroughly for 2 hours;

[0030] (3) Slowly add an alcohol solution of tetraethyl orthosilicate (the molar ratio of tetraethyl orthosilicate to anhydrous ethanol is 1:4) to the solution obtained in step (2), stir thoroughly for 1 hour, and then transfer to a 50°C water bath to react for 3 hours to form a sol-gel;

[0031] (4) After aging the sol-gel obtained in step (3) at room temperature for 6-24 hours, the obtained gel is filtered and washed until the residual liquid is neutral;

[0032] (5) drying the gel obtained in step (4) at 80-150°C under vacuum or atmospheric pressure for 12-36 hours;

[0033] (6) calcining the solid obtained in step (5) at 400-600° C. for 4-24 h to obtain the catalyst.

[0034] Wherein, the precursor of CuO is one or more of copper nitrate, copper sulfate, copper acetate, copper acetylacetonate, and copper chloride.

[0035] In order to make the contents of the present invention easier to understand, the technical solutions of the present invention are further described below in conjunction with specific implementation methods, but the present invention is not limited thereto.

[0036] Example 130 CuO-2GaN / SiO2

[0037] 18.22 g of copper nitrate trihydrate was weighed and dissolved in 50 ml of deionized water, stirring continuously until the solution became transparent. 0.4 g of gallium nitride powder was then added to the solution, ultrasonically dispersed for 30 minutes, and then stirred for 2 hours to allow the inorganic salt and gallium nitride to be thoroughly mixed and adsorbed. A mixed solution of 47.16 g of tetraethyl orthosilicate and 41.72 g of anhydrous ethanol was then slowly added dropwise. After stirring for 1 hour, the mixture was transferred to a 50°C water bath and allowed to react for 3 hours until a sol-gel formed. The resulting gel was aged at room temperature for 12 hours, filtered, washed until the raffinate was neutral, and dried in a 120°C oven for 12 hours. The resulting solid was calcined at 500°C for 6 hours to obtain the catalyst 30CuO-2GaN / SiO2. The resulting catalyst was compacted and shaped, then crushed and sieved into 14-20 mesh granules.

[0038] Comparative Example 130CuO / SiO2

[0039] Weigh 18.22 g of copper nitrate trihydrate and dissolve it in 50 ml of deionized water. Stir continuously until the solution is transparent. Then, slowly add a mixed solution of 48.55 g of tetraethyl orthosilicate and 42.95 g of anhydrous ethanol dropwise. Stir thoroughly for 1 hour, then transfer to a 50°C water bath and allow to react for 3 hours until a sol-gel is formed. The resulting gel is aged at room temperature for 12 hours, filtered, washed until the raffinate is neutral, and dried in a 120°C oven for 12 hours. The resulting solid is calcined at 500°C for 6 hours to obtain the catalyst 30CuO / SiO2. The resulting catalyst is compacted and shaped, then crushed and sieved into 14-20 mesh granules.

[0040] Comparative Example 230CuO-3Ga2O3 / SiO2

[0041] 18.22 g of copper nitrate trihydrate was weighed and dissolved in 50 ml of deionized water, stirring continuously until the solution became transparent. 0.6 g of gallium oxide powder was then added to the solution, ultrasonically dispersed for 30 minutes, and then stirred for 2 hours to allow the inorganic salt and gallium oxide to mix and absorb thoroughly. A mixed solution of 46.46 g of tetraethyl orthosilicate and 41.10 g of anhydrous ethanol was then slowly added dropwise. After stirring for 1 hour, the mixture was transferred to a 50°C water bath and allowed to react for 3 hours until a sol-gel formed. The resulting gel was aged at room temperature for 12 hours, filtered, washed until the raffinate was neutral, and dried in a 120°C oven for 12 hours. The resulting solid was calcined at 500°C for 6 hours to obtain the catalyst 30CuO-2Ga2O3 / SiO2. The resulting catalyst was compacted, crushed, and sieved into 14-20 mesh granules.

[0042] Comparative Example 330CuO-3InN / SiO2

[0043] 18.22 g of copper nitrate trihydrate was weighed and dissolved in 50 ml of deionized water, stirring continuously until the solution became transparent. 0.6 g of indium nitride powder was then added to the solution, ultrasonically dispersed for 30 minutes, and then stirred vigorously for 2 hours to ensure thorough mixing and adsorption of the inorganic salt and indium nitride. A mixed solution of 46.46 g of tetraethyl orthosilicate and 41.10 g of anhydrous ethanol was then slowly added dropwise. After stirring for 1 hour, the mixture was transferred to a 50°C water bath and allowed to react for 3 hours until a sol-gel formed. The resulting gel was aged at room temperature for 12 hours, filtered, washed until the raffinate was neutral, and dried in a 120°C oven for 12 hours. The resulting solid was calcined at 500°C for 6 hours to obtain the catalyst 30CuO-3InN / SiO2. The resulting catalyst was compacted, crushed, and sieved into 14-20 mesh granules.

[0044] Example 230 CuO-3GaN / SiO2

[0045] 18.22 g of copper nitrate trihydrate was weighed and dissolved in 50 ml of deionized water, stirring continuously until the solution became transparent. 0.6 g of gallium nitride powder was then added to the solution, ultrasonically dispersed for 30 minutes, and then stirred vigorously for 2 hours to ensure thorough mixing and adsorption of the inorganic salt and gallium nitride. A mixed solution of 46.46 g of tetraethyl orthosilicate and 41.10 g of anhydrous ethanol was then slowly added dropwise. After stirring for 1 hour, the mixture was transferred to a 50°C water bath and allowed to react for 3 hours until a sol-gel formed. The resulting gel was aged at room temperature for 12 hours, filtered, washed until the raffinate was neutral, and dried in a 120°C oven for 12 hours. The resulting solid was calcined at 500°C for 6 hours to obtain the catalyst 30CuO-3GaN / SiO2. The resulting catalyst was compacted and shaped, then crushed and sieved into 14-20 mesh granules.

[0046] Example 330 CuO-4GaN / SiO2

[0047] 18.22 g of copper nitrate trihydrate was weighed and dissolved in 50 ml of deionized water, stirring continuously until the solution became transparent. 0.8 g of gallium nitride powder was then added to the solution, ultrasonically dispersed for 30 minutes, and then stirred for 2 hours to allow the inorganic salt and gallium nitride to be thoroughly mixed and adsorbed. A mixed solution of 45.77 g of tetraethyl orthosilicate and 40.49 g of anhydrous ethanol was then slowly added dropwise. After stirring for 1 hour, the mixture was transferred to a 50°C water bath and allowed to react for 3 hours until a sol-gel formed. The resulting gel was aged at room temperature for 12 hours, filtered, washed until the raffinate was neutral, and dried in a 120°C oven for 12 hours. The resulting solid was calcined at 500°C for 6 hours to obtain the catalyst 30CuO-4GaN / SiO2. The resulting catalyst was compacted, crushed, and sieved into 14-20 mesh granules.

[0048] Example 430CuO-5GaN / SiO2

[0049] 18.22 g of copper nitrate trihydrate was weighed and dissolved in 50 ml of deionized water, stirring continuously until the solution became transparent. 1.0 g of gallium nitride powder was then added to the solution, ultrasonically dispersed for 30 minutes, and then stirred for 2 hours to allow the inorganic salt and gallium nitride to mix and absorb thoroughly. A mixed solution of 45.08 g of tetraethyl orthosilicate and 39.87 g of anhydrous ethanol was then slowly added dropwise. After stirring for 1 hour, the mixture was transferred to a 50°C water bath and allowed to react for 3 hours until a sol-gel formed. The resulting gel was aged at room temperature for 12 hours, filtered, washed until the raffinate was neutral, and dried in a 120°C oven for 12 hours. The resulting solid was calcined at 500°C for 6 hours to obtain the catalyst 30CuO-5GaN / SiO2. The resulting catalyst was compacted and shaped, then crushed and sieved into 14-20 mesh granules.

[0050] Catalyst evaluation

[0051] The catalyst performance was evaluated in a high-pressure fixed-bed reactor using a methanol solution of methyl 3-hydroxypropionate as the reactant. The catalyst loading was 10.0 ml. The catalyst was reduced with hydrogen before addition under the following conditions: temperature 320°C, pressure 6 MPa, hydrogen flow rate 100 ml / min, and reaction time 5 h. Reaction conditions: methyl 3-hydroxypropionate was diluted with methanol to a concentration of 5% by mass, temperature 150°C, pressure 6 MPa, and feed space velocity 0.1 h / min. -1 , hydrogen ester ratio 500.

[0052] After the reaction temperature stabilized for 5 h, the product from the condensate tank after the reactor was collected. The raw materials and hydrogenated products were quantitatively and qualitatively analyzed using a GC-MC coupled instrument. The conversion rate of the hydrogenation reaction of methyl 3-hydroxypropionate and the selectivity of 1,3-propylene glycol were calculated. The calculation formula is as follows. The reaction results are shown in Table 1.

[0053]

[0054] .

[0055] Table 1

[0056]

[0057] As shown in Table 1, by comparing Example 1 with Comparative Example 1, it can be seen that gallium nitride has good electronic conductivity, which is beneficial to maintaining the formed Cu 0 / Cu + The active valence state of the catalyst is increased, thereby improving the adsorption of the ester group on the catalyst, thereby improving the conversion rate and selectivity of the reaction of hydrogenating methyl 3-hydroxypropionate to 1,3-propylene glycol.

[0058] By comparing Example 1 with Comparative Examples 2 and 3, it can be seen that compared with gallium oxide and indium nitride, gallium nitride has a more stable structure and better electronic conductivity, thereby having better reaction conversion rate and selectivity.

[0059] A comparison of Examples 1-4 shows that the addition of appropriate gallium nitride helps to increase the specific surface area of ​​the catalyst. A larger specific surface area is conducive to the adsorption of more methyl 3-hydroxypropionate molecules on the active sites of the catalyst, thereby improving the conversion rate and selectivity of the hydrogenation reaction of methyl 3-hydroxypropionate to produce 1,3-propylene glycol.

[0060] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. A catalyst for hydrogenating methyl 3-hydroxypropionate to 1,3-propylene glycol, characterized in that: Includes the following components: (a) Main component CuO; (b) electron-aiding agent gallium nitride; (c) carrier and pore-enlarging agent SiO2; Calculated based on the sum of weight percentages being 100%, the contents of each component are: main component 30%, electronic auxiliary agent 2-5%, SiO2 65-68%.

2. The catalyst according to claim 1, characterized in that The crystal structure of the gallium nitride is a wurtzite structure or a zinc blende structure.

3. A method for preparing the catalyst for hydrogenating methyl 3-hydroxypropionate to 1,3-propylene glycol as claimed in claim 1, characterized in that: The steps include: (1) Dissolve the CuO precursor in deionized water and continue stirring until the solution becomes transparent; (2) Add gallium nitride powder to the solution obtained in step (1), disperse it ultrasonically, and then stir it thoroughly for 2 hours; (3) Slowly add the alcohol solution of tetraethyl orthosilicate to the solution obtained in step (2), stir thoroughly for 1 hour, and then transfer to a 50°C water bath to react for 3 hours to form a sol-gel; (4) aging the sol-gel obtained in step (3) at room temperature for 6-24 hours, filtering, and washing until the residual liquid is neutral; (5) drying the gel obtained in step (4) at 80-150°C for 12-36 hours; (6) calcining the solid obtained in step (5) at 400-600° C. for 4-24 h to obtain the catalyst.

4. The preparation method according to claim 3, characterized in that The precursor of CuO in step (1) is one or more of copper nitrate, copper sulfate, copper acetate, copper acetylacetonate, and copper chloride.

5. The preparation method according to claim 3, characterized in that The ultrasonic dispersion time in step (2) is 15-60 minutes.

6. The preparation method according to claim 3, characterized in that In the alcohol solution of tetraethyl orthosilicate in step (3), the molar ratio of tetraethyl orthosilicate to anhydrous ethanol is 1:

4.

7. Use of the catalyst as claimed in claim 1 in hydrogenating methyl 3-hydroxypropionate to produce 1,3-propylene glycol.

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