Catalyst for synthesizing glycerol carbonate by urea method as well as preparation method and application of catalyst

Abstract

The invention belongs to the technical field of catalyst preparation, and discloses a catalyst for synthesizing glycerol carbonate by a urea method as well as a preparation method and application of the catalyst. According to the method, halogen anions are intercalated into a ZnAlZr compound with a hydrotalcite-like structure through coprecipitation and high-temperature roasting to obtain an anion-modified ZnAlZr-X (X is F, Cl, Br or I) catalyst, and the anion-modified ZnAlZr-X catalyst is applied to a reaction for preparing glycerol carbonate from glycerol and urea for the first time. The catalyst has the advantages of large specific surface area, rich acid-base active sites and the like, and metal ions provide Lewis acid sites in the reaction process and are used for activating carbonyl of urea; halogen ions provide Lewis alkali sites and are used for activating hydroxyl groups of glycerol, and the Lewis alkali sites and the halogen ions cooperate to efficiently catalyze glycerol to prepare glycerol carbonate. The catalyst disclosed by the invention shows excellent activity and stability under mild reaction conditions, is easy to separate and good in reusability, and has a good application prospect in industry.

Description

Technical Field

[0001] The invention belongs to the technical field of catalyst preparation, and particularly relates to a method for preparing a catalyst for synthesizing glycerol carbonate. Background Art

[0002] Biodiesel has become one of the most widely studied clean energy sources due to its wide sources, renewable nature, high calorific value and low pollution. However, 0.1 tons of glycerol will be produced as a by-product for every ton of biodiesel produced. Therefore, synthesizing high value-added derivatives using glycerol as raw material can not only effectively maintain the balance of the glycerol market, but also promote the sustainable and healthy development of the biodiesel industry. Glycerol carbonate, as a high value-added glycerol derivative, has excellent properties such as high boiling point, low volatility, low toxicity, biodegradability, and good water solubility. It can be used as a solvent in the fields of cosmetics and medicine. In addition, glycerol carbonate is an important organic synthesis intermediate and can be used in the preparation of a variety of polyester compounds, such as polycarbonate, polyacrylic acid ester, polyurethane, polyamide, etc. Glycerol carbonate also has high reactivity and can be used as an intermediate in organic reactions, such as reacting with isocyanate and acrylate to produce glycerol carbonate (meth) acrylate, glycerol glucoside, etc., and has a very broad market prospect.

[0003] At present, the methods for synthesizing glycerol carbonate using glycerol as raw material mainly include phosgene method, CO 2 Carbonylation, transesterification and urea alcoholysis. Patents US2446145 and JP6009610 describe a process for preparing glycerol carbonate by phosgene method. This method has the advantages of high conversion rate and good selectivity, but the raw material phosgene is a highly toxic substance. During the reaction, a large amount of hydrogen chloride gas is produced, causing environmental pollution. It has been basically eliminated. Patents CN116042597A, CN110652979B, CN114177900A, and CN113908877A describe the preparation of glycerol carbonate by transesterification of glycerol and organic carbonate. The raw materials of this method are less toxic and the reaction conditions are mild, but it usually requires the addition of an excess of carbonate, which has low economic benefits and is not conducive to industrial application. Patents CN113816852B, CN108722479B, CN104815683A, and CN109621939A describe the use of CO 2 The carbonylation method for preparing glycerol carbonate is economical, environmentally friendly, and has a high atomic utilization rate. However, due to thermodynamic limitations, the yield of glycerol carbonate is low, the reaction conditions are relatively harsh, and the catalyst is prone to poisoning and deactivation. Compared with other methods, the urea alcoholysis method has the following advantages: (1) Urea is widely available and low in price, and the cost of raw materials is significantly reduced, which has obvious economic advantages; (2) The reaction by-product NH 3 Can be further combined with CO 2 The reaction produces urea, and the byproduct NH 3While making full use of it, it consumes greenhouse gas CO 2 , with a certain atomic economy; (3) the reaction conditions are mild, and it is a green, economical and environmentally friendly reaction process with good industrial prospects.

[0004] At present, the catalyst for the reaction of glycerol and urea mainly includes homogeneous catalyst and heterogeneous catalyst. Patent CN102285957A, CN102952110A, US6025504 describe the synthesis of glycerol carbonate by glycerol and urea under the action of homogeneous catalyst Lewis acid salt (such as zinc sulfate, magnesium sulfate, manganese sulfate, etc.), and the process production cost is low, but the separation and purification of the product after the reaction is difficult, and the catalyst is difficult to recycle. To solve the problem of the difficulty of recycling homogeneous catalysts, patents CN114094554A and CN114934930A prepare heterogeneous non-metallic catalysts for the reaction of glycerol and urea synthesis of glycerol carbonate, and the catalyst preparation method is green and environmentally friendly, easy to separate, but the stability of non-metallic catalysts is poor, and catalytic performance is far less than that of metal catalysts. In order to further improve the stability and catalytic performance of the catalyst, patent CN102794189A discloses a catalyst for synthesizing glycerol carbonate from glycerol and urea. The catalyst is composed of magnesium oxide and other metal oxides (such as zinc oxide, calcium oxide, etc.) supported on hydroxyapatite. Under optimized conditions, the yield of glycerol carbonate is 78%, but the metal oxide catalyst has limited active sites. Acetonitrile is also added as a solvent during the reaction, which increases the difficulty of subsequent product separation and purification and increases the reaction cost.

[0005] In summary, the current process of preparing glycerol carbonate from urea and glycerol has key problems such as poor catalyst stability, insufficient exposure of active sites, and short catalyst life. Summary of the invention

[0006] In view of the above technical problems, the present invention provides a catalyst for synthesizing glycerol carbonate by urea method, and a preparation method and application thereof.

[0007] To achieve the above object, the technical solution of the present invention is implemented as follows:

[0008] A method for preparing a catalyst for synthesizing glycerol carbonate by a urea process comprises the following steps:

[0009] (1) Dissolve Zn salt, Al salt, Zr salt and sodium halide in deionized water to obtain solution A;

[0010] (2) dissolving sodium hydroxide and anhydrous sodium carbonate in deionized water to obtain solution B;

[0011] (3) Solution A and solution B are slowly added to deionized water under stirring, and the pH is maintained at 8 during the dropwise addition. After the dropwise addition is completed, the mixed solution is aged at a certain temperature, washed with deionized water until neutral, dried, and calcined to obtain a catalyst for synthesizing glycerol carbonate by the urea method.

[0012] In the above step (1), Zn 2+ 、Al 3+ and Zr 4+ The molar ratio is (1-5):0.7:0.3.

[0013] In the above step (1), Zn 2+ 、Al 3+ and Zr 4+ The molar ratio of the total amount of the three metal ions to the halogen ions in the sodium halide is 1:(0.1-3).

[0014] Furthermore, in the above step (1), the sodium halide is any one of sodium fluoride, sodium chloride, sodium bromide and sodium iodide.

[0015] The molar ratio of sodium hydroxide to anhydrous sodium carbonate in the above step (2) is (2-5):1.

[0016] In the above step (3), the aging temperature is 60-100°C and the time is 10-20h; the calcination temperature is 400-600°C and the time is 3-5h.

[0017] The catalyst for synthesizing glycerol carbonate by the urea process is prepared by the above preparation method.

[0018] The application of the catalyst for synthesizing glycerol carbonate by the urea process in synthesizing glycerol carbonate.

[0019] Furthermore, the process conditions for synthesizing glycerol carbonate are as follows: glycerol and urea are mixed under a vacuum degree of 0.1 MPa, a catalyst is added, and glycerol carbonate is obtained through reaction.

[0020] The molar ratio of the glycerol to the urea is (0.8-1.2):1; the mass of the catalyst is 6-12% of the urea; the reaction temperature is 120-150°C and the reaction time is 1-5h.

[0021] The beneficial effects produced by the present invention are:

[0022] (1) The present invention prepares an anion-modified mixed metal oxide catalyst for the synthesis of glycerol carbonate by urea method, successfully introduces halogen ions as alkaline sites to activate the hydroxyl groups of glycerol during the reaction, and the metal ions (Zn 2+ 、Al 3+ and Zr 4+) as acidic sites to activate the carbonyl group of urea. The catalyst has a large specific surface area and abundant active sites, with the acidic site content reaching 0.53 mmol / g and the basic site content reaching 0.32 mmol / g. It can efficiently catalyze glycerol to prepare glycerol carbonate. Specifically, the conversion rate of glycerol can be as high as 99.25%, and the yield of glycerol carbonate can be as high as 98.56%.

[0023] (2) The anion-modified mixed metal oxide catalyst prepared by the present invention has high catalytic activity, good product selectivity, easy separation of the catalyst from the product, good recycling performance, and has good application prospects in industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 The XRD diagrams of the catalysts prepared in Example 1 and Comparative Example 1 are shown in FIG.

[0026] Figure 2 The SEM images of the catalysts prepared in Example 1 and Comparative Example 1 are shown in FIG. 1 , wherein (a) is Comparative Example 1 and (b) is Example 1. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Example 1

[0029] The preparation method of the catalyst for synthesizing glycerol carbonate by urea process of the present embodiment comprises the following steps:

[0030] (1) Weigh 11.894 g Zn(NO) in a molar ratio of Zn:Al:Zr = 3:0.7:0.3 3 ) 2 6H 2 O, 3.5 g Al(NO 3 ) 3 9H 2 O, 1.716 g Zr(NO 3 ) 4·5H 2 O and 1.558 g NaCl (n Cl - :n 金属 =0.5:1) Add 100 mL of deionized water and stir evenly, record as solution A. Weigh 8 g NaOH and 5.3 g Na 2 CO 3 (n NaOH :n Na2CO3 =4:1) was prepared into 100 mL of deionized water and recorded as solution B.

[0031] (2) Solution A and solution B were simultaneously added dropwise to 100 mL of deionized water, pH = 8, stirred and aged at 60 ° C for 15 h, cooled to room temperature, filtered, washed with deionized water until neutral, dried at 80 ° C for 11 h, and calcined at 500 ° C for 4 h to obtain ZnAlZr-Cl 0.5 catalyst.

[0032] Figure 1 The XRD pattern of the catalyst prepared in this example shows that ZnAl 2 O 4 The characteristic diffraction peaks of spinel, 2θ = 47.5°, 56.5°, 62.8° and 67.9°, were detected corresponding to the diffraction peaks of ZnO, and no obvious ZrO was observed. 2 and the diffraction peaks of halides, which means that they exist in an amorphous form. The shift of the diffraction peaks toward lower 2θ values ​​can be attributed to the weaker electrostatic attraction between the halogen ions and the hydrotalcite layers, resulting in an increase in the interlayer distance, which means that the halogen ions successfully enter the interlayer.

[0033] Figure 2 b is the SEM image of the catalyst prepared in this example. It can be seen from the figure that the sample maintains a morphology similar to that of the layered hydrotalcite precursor. Figure 2 Compared with a), more uniform and thinner flakes were observed in the ZnAlZr-Cl catalyst, which can be explained by the increase in the specific surface area of ​​ZnAlZr-Cl due to dehydroxylation and decarbonylation during the decomposition process. 0.5 The formation of thinner flakes improves the dispersion of metals, thereby exposing more active sites.

[0034] Application Example 1

[0035] The application of the catalyst for synthesizing glycerol carbonate by the urea method of this embodiment is specifically ZnAlZr-Cl 0.5Application as a catalyst in the synthesis of glycerol carbonate by urea method. The specific process of synthesizing glycerol carbonate by urea method is: weigh 9.2g glycerol, 6.12g urea, 0.612g (10wt% urea) catalyst and add them into a 100mL three-necked flask (with a magnet), put the three-necked flask into a heating jacket, seal the device, turn on the circulating water, evacuate (0.1MPa), turn on heating and stirring, cover the three-necked flask in the heating jacket with quartz sand to keep it warm, and wait for the temperature to rise to 140℃ to react for 3h. After the reaction is completed, take out the reaction product, analyze the product composition by gas chromatography, and the conversion rate of glycerol is 98.67%, and the selectivity of glycerol carbonate is 99.08%.

[0036] When the catalyst of this example is used for the reaction of glycerol and urea, the effect of the ratio of the amount of glycerol to urea on the reaction activity is shown in Table 1.

[0037] Table 1 Effect of the ratio of glycerol to urea on the reaction activity

[0038]

[0039] When the catalyst of this example is used for the reaction of glycerol and urea, the effect of the amount of catalyst on the reaction activity is shown in Table 2.

[0040] Table 2 Effect of catalyst dosage on reaction activity

[0041]

[0042]

[0043] When the catalyst of this example is used for the reaction of glycerol and urea, the effect of reaction time on the reaction activity is shown in Table 3.

[0044] Table 3 Effect of reaction time on reaction activity

[0045]

[0046] When the catalyst of this example is used for the reaction of glycerol and urea, the effect of reaction temperature on the reaction activity is shown in Table 4.

[0047] Table 4 Effect of reaction temperature on reaction activity

[0048]

[0049] After optimizing the conditions, it can be found that in ZnAlZr-Cl 0.5 In the reaction of catalyzing the reaction of glycerol and urea to synthesize glycerol carbonate, the optimal reaction conditions are: the molar ratio of glycerol to urea is 1.02:1, the mass fraction of catalyst to urea is 10%, the reaction time is 3h, and the reaction temperature is 140℃.

[0050] Example 2

[0051] The method for preparing the catalyst for synthesizing glycerol carbonate by the urea process of this embodiment is different from that of Example 1 in that NaCl is replaced with 1.118 g NaF in step (1). The specific steps are as follows:

[0052] (1) Weigh 11.894 g Zn(NO) in a molar ratio of Zn:Al:Zr = 3:0.7:0.3 3 ) 2 6H 2 O, 3.5 g Al(NO 3 ) 3 9H 2 O, 1.716 g Zr(NO 3 ) 4 ·5H 2 O and 1.118 g NaF (n F - :n 金属 =0.5:1) Add 100 mL of deionized water and stir evenly, record as solution A. Weigh 8 g NaOH and 5.3 g Na 2 CO 3 (n NaOH :n Na2CO3 =4:1) was prepared into 100 mL of deionized water and recorded as solution B.

[0053] (2) Solution A and solution B were simultaneously added dropwise to 100 mL of deionized water, pH = 8, stirred and aged at 60 ° C for 15 h, cooled to room temperature, filtered, washed with deionized water until neutral, dried at 80 ° C for 11 h, and calcined at 500 ° C for 4 h to obtain ZnAlZr-F 0.5 catalyst.

[0054] Application Example 2

[0055] The process for synthesizing glycerol carbonate by urea method uses the catalyst of this example, and other parameters are the same as those of Example 1. Finally, gas chromatography analysis shows that the conversion rate of glycerol is 97.03%, and the selectivity of glycerol carbonate is 99.56%.

[0056] Example 3

[0057] The method for preparing the catalyst for synthesizing glycerol carbonate by the urea process of this embodiment is different from that of Example 1 in that NaCl is replaced with 2.742 g NaBr in step (1). The specific steps are as follows:

[0058] (1) Weigh 11.894 g Zn(NO) in a molar ratio of Zn:Al:Zr = 3:0.7:0.3 3 )2 6H 2 O, 3.5 g Al(NO 3 ) 3 9H 2 O, 1.716 g Zr(NO 3 ) 4 ·5H 2 O and 2.742 g NaBr (n Br - :n 金属 =0.5:1) Add 100 mL of deionized water and stir evenly, record as solution A. Weigh 8 g NaOH and 5.3 g Na 2 CO 3 (n NaOH :n Na2CO3 =4:1) was prepared into 100 mL of deionized water and recorded as solution B.

[0059] (2) Solution A and solution B were simultaneously added dropwise to 100 mL of deionized water, pH = 8, stirred and aged at 60 ° C for 15 h, cooled to room temperature, filtered, washed with deionized water until neutral, dried at 80 ° C for 11 h, and calcined at 500 ° C for 4 h to obtain ZnAlZr-Br 0.5 catalyst.

[0060] Application Example 3

[0061] The process for synthesizing glycerol carbonate by urea method uses the catalyst of this example, and other parameters are the same as those of Example 1. Finally, gas chromatography analysis shows that the conversion rate of glycerol is 95.08%, and the selectivity of glycerol carbonate is 97.62%.

[0062] Example 4

[0063] The method for preparing the catalyst for synthesizing glycerol carbonate by the urea process of this embodiment is different from that of Example 1 in that NaCl is replaced with 3.995 g NaI in step (1). The specific steps are as follows:

[0064] (1) Weigh 11.894 g Zn(NO) in a molar ratio of Zn:Al:Zr = 3:0.7:0.3 3 ) 2 6H 2 O, 3.5 g Al(NO 3 ) 3 9H 2 O, 1.716 g Zr(NO 3 ) 4 ·5H 2 O and 3.995g NaI(n I - :n 金属=0.5:1) Add 100 mL of deionized water and stir evenly, record as solution A. Weigh 8 g NaOH and 5.3 g Na 2 CO 3 (n NaOH :n Na2CO3 =4:1) was prepared into 100 mL of deionized water and recorded as solution B.

[0065] (2) Solution A and solution B were simultaneously added dropwise to 100 mL of deionized water, pH = 8, stirred and aged at 60 ° C for 15 h, cooled to room temperature, filtered, washed with deionized water until neutral, dried at 80 ° C for 11 h, and calcined at 500 ° C for 4 h to obtain ZnAlZr-I 0.5 catalyst.

[0066] Application Example 4

[0067] The process for synthesizing glycerol carbonate by urea method uses the catalyst of this example, and other parameters are the same as those of Example 1. Finally, the conversion rate of glycerol obtained by gas chromatography analysis is 92.77%, and the selectivity of glycerol carbonate is 94.96%.

[0068] Example 5

[0069] The method for preparing the catalyst for synthesizing glycerol carbonate by the urea process of this embodiment is different from that of Example 1 in that the molar ratio of Zn:Al:Zr in step (1) is 1:0.7:0.3. The specific steps are as follows:

[0070] (1) In a molar ratio of Zn:Al:Zr = 1:0.7:0.3, weigh 7.928 g Zn(NO 3 ) 2 6H 2 O, 6.998 g Al(NO 3 ) 3 9H 2 O, 3.432 g Zr(NO 3 ) 4 ·5H 2 O and 1.558 g NaCl (n Cl - :n 金属 =0.5:1) Add 100 mL of deionized water and stir evenly, record as solution A. Weigh 8 g NaOH and 5.3 g Na 2 CO 3 (n NaOH :n Na2CO3 =4:1) was prepared into 100 mL of deionized water and recorded as solution B.

[0071] (2) Solution A and solution B were simultaneously added dropwise to 100 mL of deionized water, pH = 8, stirred and aged at 60 ° C for 15 h, cooled to room temperature, filtered, washed with deionized water until neutral, dried at 80 ° C for 11 h, and calcined at 500 ° C for 4 h to obtain ZnAlZr-Cl 0.5 catalyst.

[0072] Application Example 5

[0073] The process for synthesizing glycerol carbonate by urea method uses the catalyst of this example, and other parameters are the same as those of Example 1. Finally, gas chromatography analysis shows that the conversion rate of glycerol is 83.74%, and the selectivity of glycerol carbonate is 96.12%.

[0074] Example 6

[0075] The method for preparing the catalyst for synthesizing glycerol carbonate by the urea process of this embodiment is different from that of Example 1 in that the molar ratio of Zn:Al:Zr in step (1) is 5:0.7:0.3. The specific steps are as follows:

[0076] (1) In a molar ratio of Zn:Al:Zr = 5:0.7:0.3, weigh 13.214 g Zn(NO 3 ) 2 6H 2 O, 2.333 g Al(NO 3 ) 3 9H 2 O, 1.144 g Zr(NO 3 ) 4 ·5H 2 O and 1.558 g NaCl (n Cl - :n 金属 =0.5:1) Add 100 mL of deionized water and stir evenly, record as solution A. Weigh 8 g NaOH and 5.3 g Na 2 CO 3 (n NaOH :n Na2CO3 =4:1) was prepared into 100 mL of deionized water and recorded as solution B.

[0077] (2) Solution A and solution B were simultaneously added dropwise to 100 mL of deionized water, pH = 8, stirred and aged at 60 ° C for 15 h, cooled to room temperature, filtered, washed with deionized water until neutral, dried at 80 ° C for 11 h, and calcined at 500 ° C for 4 h to obtain ZnAlZr-Cl 0.5 catalyst.

[0078] Application Example 6

[0079] The process for synthesizing glycerol carbonate by urea method uses the catalyst of this example, and other parameters are the same as those of Example 1. Finally, gas chromatography analysis shows that the conversion rate of glycerol is 95.02%, and the selectivity of glycerol carbonate is 92.64%.

[0080] Example 7

[0081] The method for preparing the catalyst for synthesizing glycerol carbonate by the urea method of this embodiment is different from that of Example 1 in that in step (1), Cl -:n 金属 =0.1:1 Weigh 0.312g NaCl, the specific steps are as follows:

[0082] (1) Weigh 11.894 g Zn(NO) in a molar ratio of Zn:Al:Zr = 3:0.7:0.3 3 ) 2 6H 2 O, 3.5 g Al(NO 3 ) 3 9H 2 O, 1.716 g Zr(NO 3 ) 4 ·5H 2 O and 0.312 g NaCl (n Cl - :n 金属 =0.1:1) Add 100 mL of deionized water and stir evenly, record as solution A. Weigh 8 g NaOH and 5.3 g Na 2 CO 3 (n NaOH :n Na2CO3 =4:1) was prepared into 100 mL of deionized water and recorded as solution B.

[0083] (2) Solution A and solution B were simultaneously added dropwise to 100 mL of deionized water, pH = 8, stirred and aged at 60 ° C for 15 h, cooled to room temperature, filtered, washed with deionized water until neutral, dried at 80 ° C for 11 h, and calcined at 500 ° C for 4 h to obtain ZnAlZr-Cl 0.1 catalyst.

[0084] Application Example 7

[0085] The process for synthesizing glycerol carbonate by urea method uses the catalyst of this example, and other parameters are the same as those of Example 1. Finally, the conversion rate of glycerol obtained by gas chromatography analysis is 89.88%, and the selectivity of glycerol carbonate is 100%.

[0086] Example 8

[0087] The method for preparing the catalyst for synthesizing glycerol carbonate by the urea method of this embodiment is different from that of Example 1 in that in step (1), Cl- :n metal = 0.3:1 Weigh 0.935g NaCl, the specific steps are as follows:

[0088] (1) Weigh 11.894 g Zn(NO) in a molar ratio of Zn:Al:Zr = 3:0.7:0.3 3 ) 2 6H 2 O, 3.5 g Al(NO 3 ) 3 9H 2 O, 1.716 g Zr(NO 3 ) 4 ·5H 2 O and 0.935 g NaCl (n Cl - :n 金属 =0.3:1) Add 100 mL of deionized water and stir evenly, record as solution A. Weigh 8 g NaOH and 5.3 g Na 2 CO 3 (n NaOH :n Na2CO3 =4:1) was prepared into 100 mL of deionized water and recorded as solution B.

[0089] (2) Solution A and solution B were simultaneously added dropwise to 100 mL of deionized water, pH = 8, stirred and aged at 60 ° C for 15 h, cooled to room temperature, filtered, washed with deionized water until neutral, dried at 80 ° C for 11 h, and calcined at 500 ° C for 4 h to obtain ZnAlZr-Cl 0.3 catalyst.

[0090] Application Example 8

[0091] The process for synthesizing glycerol carbonate by urea method uses the catalyst of this example, and other parameters are the same as those of Example 1. Finally, the conversion rate of glycerol obtained by gas chromatography analysis is 94.62%, and the selectivity of glycerol carbonate is 99.76%.

[0092] Example 9

[0093] The method for preparing the catalyst for synthesizing glycerol carbonate by the urea method of this embodiment is different from that of Example 1 in that in step (1), Cl - :n 金属 =1:1 Weigh 3.118g NaCl, the specific steps are as follows:

[0094] (1) Weigh 11.894 g Zn(NO) in a molar ratio of Zn:Al:Zr = 3:0.7:0.33 ) 2 6H 2 O, 3.5 g Al(NO 3 ) 3 9H 2 O, 1.716 g Zr(NO 3 ) 4 ·5H 2 O and 3.118 g NaCl (n Cl - :n 金属 =1:1) add 100 mL of deionized water and stir evenly, record as solution A. Weigh 8 g NaOH and 5.3 g Na 2 CO 3 (n NaOH :n Na2CO3 =4:1) was prepared into 100 mL of deionized water and recorded as solution B.

[0095] (2) Solution A and solution B were simultaneously added dropwise to 100 mL of deionized water, pH = 8, stirred and aged at 60 ° C for 15 h, cooled to room temperature, filtered, washed with deionized water until neutral, dried at 80 ° C for 11 h, and calcined at 500 ° C for 4 h to obtain ZnAlZr-Cl 1 catalyst.

[0096] Application Example 9

[0097] The process for synthesizing glycerol carbonate by urea method uses the catalyst of this example, and other parameters are the same as those of Example 1. Finally, gas chromatography analysis shows that the conversion rate of glycerol is 98.03%, and the selectivity of glycerol carbonate is 97.91%.

[0098] Example 10

[0099] The method for preparing the catalyst for synthesizing glycerol carbonate by the urea method of this embodiment is different from that of Example 1 in that in step (1), Cl - :n 金属 =2:1 Weigh 6.236g NaCl, the specific steps are as follows:

[0100] (1) Weigh 11.894 g Zn(NO) in a molar ratio of Zn:Al:Zr = 3:0.7:0.3 3 ) 2 6H 2 O, 3.5 g Al(NO 3 ) 3 9H 2 O, 1.716 g Zr(NO 3 ) 4 ·5H 2O and 6.236 g NaCl (n Cl - :n 金属 =2:1) ​​Add 100 mL of deionized water and stir evenly, record as solution A. Weigh 8 g NaOH and 5.3 g Na 2 CO 3 (n NaOH :n Na2CO3 =4:1) was prepared into 100 mL of deionized water and recorded as solution B.

[0101] (2) Solution A and solution B were simultaneously added dropwise to 100 mL of deionized water, pH = 8, stirred and aged at 60 ° C for 15 h, cooled to room temperature, filtered, washed with deionized water until neutral, dried at 80 ° C for 11 h, and calcined at 500 ° C for 4 h to obtain ZnAlZr-Cl 2 catalyst.

[0102] Application Example 10

[0103] The process for synthesizing glycerol carbonate by urea method uses the catalyst of this example, and other parameters are the same as those of Example 1. Finally, gas chromatography analysis shows that the conversion rate of glycerol is 95.72%, and the selectivity of glycerol carbonate is 94.07%.

[0104] Embodiment 11

[0105] The method for preparing the catalyst for synthesizing glycerol carbonate by the urea method of this embodiment is different from that of Example 1 in that in step (1), Cl - :n 金属 =3:1 Weigh 9.354g NaCl, the specific steps are as follows:

[0106] (1) Weigh 11.894 g Zn(NO) in a molar ratio of Zn:Al:Zr = 3:0.7:0.3 3 ) 2 6H 2 O, 3.5 g Al(NO 3 ) 3 9H 2 O, 1.716 g Zr(NO 3 ) 4 ·5H 2 O and 9.354NaCl (n Cl - :n 金属 =3:1) Add 100 mL of deionized water and stir evenly, record as solution A. Weigh 8 g NaOH and 5.3 g Na 2 CO 3 (n NaOH :nNa2CO3 =4:1) was prepared into 100 mL of deionized water and recorded as solution B.

[0107] (2) Solution A and solution B were simultaneously added dropwise to 100 mL of deionized water, pH = 8, stirred and aged at 60 ° C for 15 h, cooled to room temperature, filtered, washed with deionized water until neutral, dried at 80 ° C for 11 h, and calcined at 500 ° C for 4 h to obtain ZnAlZr-Cl 3 catalyst.

[0108] Application Example 11

[0109] The process for synthesizing glycerol carbonate by urea method uses the catalyst of this example, and other parameters are the same as those of Example 1. Finally, gas chromatography analysis shows that the conversion rate of glycerol is 93.41%, and the selectivity of glycerol carbonate is 90.83%.

[0110] Example 12

[0111] The preparation method of the catalyst for synthesizing glycerol carbonate by urea method in this embodiment is different from that in Example 1 in that 6.67 g NaOH and 8.83 g Na 2 CO 3 (n NaOH :n Na2CO3 =2:1) ​​into 100 mL of deionized water, referred to as solution B. The specific steps are as follows:

[0112] (1) Weigh 11.894 g Zn(NO) in a molar ratio of Zn:Al:Zr = 3:0.7:0.3 3 ) 2 6H 2 O, 3.5 g Al(NO 3 ) 3 9H 2 O, 1.716 g Zr(NO 3 ) 4 ·5H 2 O and 1.558 g NaCl (n Cl - :n 金属 =0.5:1) Add 100 mL of deionized water and stir evenly, record as solution A. Weigh 6.67 g NaOH and 8.83 g Na 2 CO 3 (n NaOH :n Na2CO3 =2:1) ​​was prepared into 100 mL of deionized water and recorded as solution B.

[0113] (2) Solution A and solution B were simultaneously added dropwise to 100 mL of deionized water, pH = 8, stirred and aged at 60 ° C for 15 h, cooled to room temperature, filtered, washed with deionized water until neutral, dried at 80 ° C for 11 h, and calcined at 500 ° C for 4 h to obtain ZnAlZr-Cl 0.5 catalyst.

[0114] Application Example 12

[0115] The process for synthesizing glycerol carbonate by urea method uses the catalyst of this example, and other parameters are the same as those of Example 1. Finally, gas chromatography analysis shows that the conversion rate of glycerol is 67.14%, and the selectivity of glycerol carbonate is 63.89%.

[0116] Embodiment 13

[0117] The preparation method of the catalyst for synthesizing glycerol carbonate by urea method in this embodiment is different from that in Example 1 in that 7.5 g NaOH and 6.63 g Na 2 CO 3 (n NaOH :n Na2CO3 =3:1) into 100 mL of deionized water, referred to as solution B. The specific steps are as follows:

[0118] (1) Weigh 11.894 g Zn(NO) in a molar ratio of Zn:Al:Zr = 3:0.7:0.3 3 ) 2 6H 2 O, 3.5 g Al(NO 3 ) 3 9H 2 O, 1.716 g Zr(NO 3 ) 4 ·5H 2 O and 1.558 g NaCl (n Cl - :n 金属 =0.5:1) Add 100 mL of deionized water and stir evenly, record as solution A. Weigh 7.5 g NaOH and 6.63 g Na 2 CO 3 (n NaOH :n Na2CO3 =3:1) was prepared in 100 mL of deionized water and recorded as solution B.

[0119] (2) Solution A and solution B were simultaneously added dropwise to 100 mL of deionized water, pH = 8, stirred and aged at 60 ° C for 15 h, cooled to room temperature, filtered, washed with deionized water until neutral, dried at 80 ° C for 11 h, and calcined at 500 ° C for 4 h to obtain ZnAlZr-Cl 0.5catalyst.

[0120] Application Example 13

[0121] The process for synthesizing glycerol carbonate by urea method uses the catalyst of this example, and other parameters are the same as those of Example 1. Finally, the conversion rate of glycerol obtained by gas chromatography analysis is 76.59%, and the selectivity of glycerol carbonate is 80.03%.

[0122] Embodiment 14

[0123] The preparation method of the catalyst for synthesizing glycerol carbonate by urea method in this embodiment is different from that in Example 1 in that 8.33 g NaOH and 4.42 g Na 2 CO 3 (n NaOH :n Na2CO3 =5:1) into 100 mL of deionized water, referred to as solution B. The specific steps are as follows:

[0124] (1) Weigh 11.894 g Zn(NO) in a molar ratio of Zn:Al:Zr = 3:0.7:0.3 3 ) 2 6H 2 O, 3.5 g Al(NO 3 ) 3 9H 2 O, 1.716 g Zr(NO 3 ) 4 ·5H 2 O and 1.558 g NaCl (n Cl - :n 金属 =0.5:1) Add 100 mL of deionized water and stir evenly, record as solution A. Weigh 8.33 g NaOH and 4.42 g Na 2 CO 3 (n NaOH :n Na2CO3 =5:1) was prepared into 100 mL of deionized water and recorded as solution B.

[0125] (2) Solution A and solution B were simultaneously added dropwise to 100 mL of deionized water, pH = 8, stirred and aged at 60 ° C for 15 h, cooled to room temperature, filtered, washed with deionized water until neutral, dried at 80 ° C for 11 h, and calcined at 500 ° C for 4 h to obtain ZnAlZr-Cl 0.5 catalyst.

[0126] Application Example 14

[0127] The process for synthesizing glycerol carbonate by urea method uses the catalyst of this example, and other parameters are the same as those of Example 1. Finally, gas chromatography analysis shows that the conversion rate of glycerol is 87.69%, and the selectivity of glycerol carbonate is 74.37%.

[0128] Embodiment 15

[0129] The method for preparing the catalyst for synthesizing glycerol carbonate by the urea process of this embodiment is different from that of Example 1 in that the aging temperature in step (2) is 80° C. The specific steps are as follows:

[0130] (1) Weigh 11.894 g Zn(NO) in a molar ratio of Zn:Al:Zr = 3:0.7:0.3 3 ) 2 6H 2 O, 3.5 g Al(NO 3 ) 3 9H 2 O, 1.716 g Zr(NO 3 ) 4 ·5H 2 O and 1.558 g NaCl (n Cl - :n 金属 =0.5:1) Add 100 mL of deionized water and stir evenly, record as solution A. Weigh 8 g NaOH and 5.3 g Na 2 CO 3 (n NaOH :n Na2CO3 =4:1) was prepared into 100 mL of deionized water and recorded as solution B.

[0131] (2) Solution A and solution B were simultaneously added dropwise to 100 mL of deionized water, pH = 8, stirred and aged at 80 ° C for 15 h, cooled to room temperature, filtered, washed with deionized water until neutral, dried at 80 ° C for 11 h, and calcined at 500 ° C for 4 h to obtain ZnAlZr-Cl 0.5 catalyst.

[0132] Application Example 15

[0133] The process for synthesizing glycerol carbonate by urea method uses the catalyst of this example, and other parameters are the same as those of Example 1. Finally, gas chromatography analysis shows that the conversion rate of glycerol is 91.73%, and the selectivity of glycerol carbonate is 93.41%.

[0134] Example 16

[0135] The method for preparing the catalyst for synthesizing glycerol carbonate by the urea process of this embodiment is different from that of Example 1 in that the aging temperature in step (2) is 100° C. The specific steps are as follows:

[0136] (1) Weigh 11.894 g Zn(NO) in a molar ratio of Zn:Al:Zr = 3:0.7:0.3 3 ) 2 6H 2 O, 3.5 g Al(NO 3 ) 3 9H 2 O, 1.716 g Zr(NO 3 ) 4 ·5H 2 O and 1.558 g NaCl (n Cl - :n 金属 =0.5:1) Add 100 mL of deionized water and stir evenly, record as solution A. Weigh 8 g NaOH and 5.3 g Na 2 CO 3 (n NaOH :n Na2CO3 =4:1) was prepared into 100 mL of deionized water and recorded as solution B.

[0137] (2) Solution A and solution B were simultaneously added dropwise to 100 mL of deionized water, pH = 8, stirred and aged at 100 °C for 15 h, cooled to room temperature, filtered, washed with deionized water until neutral, dried at 80 °C for 11 h, and calcined at 500 °C for 4 h to obtain ZnAlZr-Cl 0.5 catalyst.

[0138] Application Example 16

[0139] The process for synthesizing glycerol carbonate by urea method uses the catalyst of this example, and other parameters are the same as those of Example 1. Finally, gas chromatography analysis shows that the conversion rate of glycerol is 87.05%, and the selectivity of glycerol carbonate is 90.38%.

[0140] Embodiment 17

[0141] The method for preparing the catalyst for synthesizing glycerol carbonate by the urea process of this embodiment is different from that of Example 1 in that the aging time in step (2) is 10 h. The specific steps are as follows:

[0142] (1) Weigh 11.894 g Zn(NO) in a molar ratio of Zn:Al:Zr = 3:0.7:0.3 3 ) 2 6H 2 O, 3.5 g Al(NO 3 ) 3 9H 2 O, 1.716 g Zr(NO 3 ) 4·5H 2 O and 1.558 g NaCl (n Cl - :n 金属 =0.5:1) Add 100 mL of deionized water and stir evenly, record as solution A. Weigh 8 g NaOH and 5.3 g Na 2 CO 3 (n NaOH :n Na2CO3 =4:1) was prepared into 100 mL of deionized water and recorded as solution B.

[0143] (2) Solution A and solution B were simultaneously added dropwise to 100 mL of deionized water, pH = 8, stirred and aged at 60 ° C for 10 h, cooled to room temperature, filtered, washed with deionized water until neutral, dried at 80 ° C for 11 h, and calcined at 500 ° C for 4 h to obtain ZnAlZr-Cl 0.5 catalyst.

[0144] Application Example 17

[0145] The process for synthesizing glycerol carbonate by urea method uses the catalyst of this example, and other parameters are the same as those of Example 1. Finally, gas chromatography analysis shows that the conversion rate of glycerol is 59.82%, and the selectivity of glycerol carbonate is 67.19%.

[0146] Embodiment 18

[0147] The method for preparing the catalyst for synthesizing glycerol carbonate by the urea process of this embodiment is different from that of Example 1 in that the aging time in step (2) is 20 hours, and the specific steps are as follows:

[0148] (1) Weigh 11.894 g Zn(NO) in a molar ratio of Zn:Al:Zr = 3:0.7:0.3 3 ) 2 6H 2 O, 3.5 g Al(NO 3 ) 3 9H 2 O, 1.716 g Zr(NO 3 ) 4 ·5H 2 O and 1.558 g NaCl (n Cl - :n 金属 =0.5:1) Add 100 mL of deionized water and stir evenly, record as solution A. Weigh 8 g NaOH and 5.3 g Na 2 CO 3 (n NaOH :n Na2CO3 =4:1) was prepared into 100 mL of deionized water and recorded as solution B.

[0149] (2) Solution A and solution B were simultaneously added dropwise to 100 mL of deionized water, pH = 8, stirred and aged at 60 ° C for 20 h, cooled to room temperature, filtered, washed with deionized water until neutral, dried at 80 ° C for 11 h, and calcined at 500 ° C for 4 h to obtain ZnAlZr-Cl 0.5 catalyst.

[0150] Application Example 18

[0151] The process for synthesizing glycerol carbonate by urea method uses the catalyst of this example, and other parameters are the same as those of Example 1. Finally, gas chromatography analysis shows that the conversion rate of glycerol is 82.49%, and the selectivity of glycerol carbonate is 76.27%.

[0152] Embodiment 19

[0153] The method for preparing the catalyst for synthesizing glycerol carbonate by the urea process of this embodiment is different from that of Example 1 in that the calcination temperature in step (2) is 400° C. The specific steps are as follows:

[0154] (1) Weigh 11.894 g Zn(NO) in a molar ratio of Zn:Al:Zr = 3:0.7:0.3 3 ) 2 6H 2 O, 3.5 g Al(NO 3 ) 3 9H 2 O, 1.716 g Zr(NO 3 ) 4 ·5H 2 O and 1.558 g NaCl (n Cl - :n 金属 =0.5:1) Add 100 mL of deionized water and stir evenly, record as solution A. Weigh 8 g NaOH and 5.3 g Na 2 CO 3 (n NaOH :n Na2CO3 =4:1) was prepared into 100 mL of deionized water and recorded as solution B.

[0155] (2) Solution A and solution B were simultaneously added dropwise to 100 mL of deionized water, pH = 8, stirred and aged at 60 ° C for 15 h, cooled to room temperature, filtered, washed with deionized water until neutral, dried at 80 ° C for 11 h, and calcined at 400 ° C for 4 h to obtain ZnAlZr-Cl 0.5 catalyst.

[0156] Application Example 19

[0157] The process for synthesizing glycerol carbonate by urea method uses the catalyst of this example, and other parameters are the same as those of Example 1. Finally, gas chromatography analysis shows that the conversion rate of glycerol is 92.91%, and the selectivity of glycerol carbonate is 93.04%.

[0158] Embodiment 20

[0159] The method for preparing the catalyst for synthesizing glycerol carbonate by the urea process of this embodiment is different from that of Example 1 in that the calcination temperature in step (2) is 600° C. The specific steps are as follows:

[0160] (1) Weigh 11.894 g Zn(NO) in a molar ratio of Zn:Al:Zr = 3:0.7:0.3 3 ) 2 6H 2 O, 3.5 g Al(NO 3 ) 3 9H 2 O, 1.716 g Zr(NO 3 ) 4 ·5H 2 O and 1.558 g NaCl (n Cl - :n 金属 =0.5:1) Add 100 mL of deionized water and stir evenly, record as solution A. Weigh 8 g NaOH and 5.3 g Na 2 CO 3 (n NaOH :n Na2CO3 =4:1) was prepared into 100 mL of deionized water and recorded as solution B.

[0161] (2) Solution A and solution B were simultaneously added dropwise to 100 mL of deionized water, pH = 8, stirred and aged at 60 ° C for 15 h, cooled to room temperature, filtered, washed with deionized water until neutral, dried at 80 ° C for 11 h, and calcined at 600 ° C for 4 h to obtain ZnAlZr-Cl 0.5 catalyst.

[0162] Application Example 20

[0163] The process for synthesizing glycerol carbonate by urea method uses the catalyst of this example, and other parameters are the same as those of Example 1. Finally, the conversion rate of glycerol obtained by gas chromatography analysis is 96.54%, and the selectivity of glycerol carbonate is 90.63%.

[0164] Embodiment 21

[0165] The method for preparing the catalyst for synthesizing glycerol carbonate by the urea process of this embodiment is different from that of Example 1 in that the calcination time in step (2) is 3 hours, and the specific steps are as follows:

[0166] (1) Weigh 11.894 g of Zn(NO 3 ) 2 ·6H 2 O, 3.5 g of Al(NO 3 ) 3 ·9H 2 O, 1.716 g of Zr(NO 3 ) 4 ·5H 2 O and 1.558 g of NaCl (n Cl - : n 金属 = 0.5:1) and add them to 100 mL of deionized water, stir evenly, and label it as solution A. Weigh 8 g of NaOH and 5.3 g of Na 2 CO 3 (n NaOH : n Na2CO3 = 4:1) and dissolve them in 100 mL of deionized water, label it as solution B.

[0167] (2) Drop solution A and solution B into 100 mL of deionized water simultaneously, keep the pH = 8, stir and age at 60 °C for 15 h, cool to room temperature, filter by suction, wash with deionized water until neutral, dry at 80 °C for 11 h, and calcine at 500 °C for 3 h to obtain the ZnAlZr-Cl 0.5 catalyst.

[0168] Application Example 21

[0169] In the process of synthesizing glycerol carbonate by the urea method, the catalyst of this example is used, and other parameters are the same as those in Example 1. Finally, through gas chromatography analysis, the conversion rate of glycerol is 85.73%, and the selectivity of glycerol carbonate is 92.61%.

[0170] Example 22

[0171] The preparation method of the catalyst for synthesizing glycerol carbonate by the urea method in this example is different from that in Example 1 in that the calcination time in step (2) is 5 h, and the specific steps are as follows:

[0172] (1) Weigh 11.894 g of Zn(NO 3 ) 2 ·6H 2 O, 3.5 g of Al(NO 3 ) 3 ·9H 2 O, 1.716 g of Zr(NO 3 ) 4·5H 2 O and 1.558 g NaCl (n Cl - :n 金属 =0.5:1) Add 100 mL of deionized water and stir evenly, record as solution A. Weigh 8 g NaOH and 5.3 g Na 2 CO 3 (n NaOH :n Na2CO3 =4:1) was prepared into 100 mL of deionized water and recorded as solution B.

[0173] (2) Solution A and solution B were simultaneously added dropwise to 100 mL of deionized water, pH = 8, stirred and aged at 60 ° C for 15 h, cooled to room temperature, filtered, washed with deionized water until neutral, dried at 80 ° C for 11 h, and calcined at 500 ° C for 5 h to obtain ZnAlZr-Cl 0.5 catalyst.

[0174] Application Example 22

[0175] The process for synthesizing glycerol carbonate by urea method uses the catalyst of this example, and other parameters are the same as those of Example 1. Finally, gas chromatography analysis shows that the conversion rate of glycerol is 93.17%, and the selectivity of glycerol carbonate is 94.37%.

[0176] Comparative Example 1

[0177] The preparation method of the catalyst for synthesizing glycerol carbonate by the urea process of this embodiment, the preparation steps are different from those of Example 1 in that no NaCl is added, and specifically include the following steps:

[0178] (1) According to the ratio of Zn:Al:Zr=3:0.7:0.3, weigh 11.894 g Zn(NO 3 ) 2 6H 2 O, 3.5 g Al(NO 3 ) 3 9H 2 O and 1.716gZr(NO 3 ) 4 ·5H 2 O, add 100 mL of deionized water and stir evenly, record it as solution A. Weigh 8 g of NaOH and 5.3 g of Na 2 CO 3 (n NaOH :n Na2CO3 =4:1) was prepared into 100 mL of deionized water and recorded as solution B.

[0179] (2) Solution A and solution B were simultaneously added dropwise to 100 mL of deionized water, pH = 8, stirred and aged at 60° C. for 15 h, cooled to room temperature, filtered, washed with deionized water until neutral, dried at 80° C. for 11 h, and calcined at 500° C. for 4 h to obtain a ZnAlZr catalyst.

[0180] Application Example 23

[0181] The process of synthesizing glycerol carbonate by urea method uses the catalyst of this comparative example, and other parameters are the same as those of Example 1. Finally, the conversion rate of glycerol obtained by gas chromatography analysis is 84.76%, and the selectivity of glycerol carbonate is 91.88%.

[0182] Comparative Example 2

[0183] The preparation method of the catalyst for synthesizing glycerol carbonate by urea method in this embodiment is different from that in Example 1 in that 11.894 g Zn(NO 3 ) 2 6H 2 O, 4.04 g La(NO 3 ) 3 6H 2 O, 1.716 g Zr(NO 3 ) 4 ·5H 2 O, specifically comprising the following steps:

[0184] (1) According to Zn:La:Zr=3:0.7:0.3, weigh 11.894g Zn(NO 3 ) 2 6H 2 O, 4.04 g La(NO 3 ) 3 6H 2 O, 1.716 g Zr(NO 3 ) 4 ·5H 2 O and 1.558 g NaCl (n Cl- :n 金属 =0.5:1) Add 100 mL of deionized water and stir evenly, record as solution A. Weigh 8 g NaOH and 5.3 g Na 2 CO 3 (n NaOH :n Na2CO3 =4:1) was prepared into 100 mL of deionized water and recorded as solution B.

[0185] (2) Solution A and solution B were simultaneously added dropwise to 100 mL of deionized water, pH = 8, stirred and aged at 60 ° C for 15 h, cooled to room temperature, filtered, washed with deionized water until neutral, dried at 80 ° C for 11 h, and calcined at 500 ° C for 4 h to obtain ZnLaZr-Cl 0.5 catalyst.

[0186] Application Example 24

[0187] The process of synthesizing glycerol carbonate by urea method uses the catalyst of this comparative example, and other parameters are the same as those of Example 1. Finally, the conversion rate of glycerol obtained by gas chromatography analysis is 88.52%, and the selectivity of glycerol carbonate is 91.47%.

[0188] Comparative Example 3

[0189] The preparation method of the catalyst for synthesizing glycerol carbonate by urea method in this embodiment is different from that in Example 1 in that 10.253 g Mg(NO 3 ) 2 6H 2 O, 3.5 g Al(NO 3 ) 3 9H 2 O, 1.716 g Zr(NO 3 ) 4 ·5H 2 O, specifically comprising the following steps:

[0190] (1) According to the ratio of Mg:Al:Zr=3:0.7:0.3, weigh 10.253 g Mg(NO 3 ) 2 6H 2 O, 3.5 g Al(NO 3 ) 3 9H 2 O, 1.716gZr(NO 3 ) 4 ·5H 2 O and 1.558 g NaCl (n Cl- :n 金属 =0.5:1) Add 100 mL of deionized water and stir evenly, record as solution A. Weigh 8 g NaOH and 5.3 g Na 2 CO 3 (n NaOH :n Na2CO3 =4:1) was prepared into 100 mL of deionized water and recorded as solution B.

[0191] (2) Solution A and solution B were simultaneously added dropwise to 100 mL of deionized water, pH = 8, stirred and aged at 60 ° C for 15 h, cooled to room temperature, filtered, washed with deionized water until neutral, dried at 80 ° C for 11 h, and calcined at 500 ° C for 4 h to obtain MgAlZr-Cl 0.5 catalyst.

[0192] Application Example 25

[0193] The process of synthesizing glycerol carbonate by urea method uses the catalyst of this comparative example, and other parameters are the same as those of Example 1. Finally, the conversion rate of glycerol obtained by gas chromatography analysis is 83.17%, and the selectivity of glycerol carbonate is 89.95%.

[0194] Comparative Example 4

[0195] The preparation method of the catalyst for synthesizing glycerol carbonate by urea method in this embodiment is different from that in Example 1 in that Mg:La:Zr=3:0.7:0.3. 10.253 g Mg(NO 3 ) 2 6H 2 O, 4.04 g La(NO 3 ) 3 6H 2 O, 1.716 g Zr(NO 3 ) 4 ·5H 2 O, specifically comprising the following steps:

[0196] (1) According to the ratio of Mg:La:Zr=3:0.7:0.3, weigh 10.253 g Mg(NO 3 ) 2 6H 2 O, 4.04 g La(NO 3 ) 3 6H 2 O, 1.716 g Zr(NO 3 ) 4 ·5H 2 O and 1.558 g NaCl (n Cl- :n 金属 =0.5:1) Add 100 mL of deionized water and stir evenly, record as solution A. Weigh 8 g NaOH and 5.3 g Na 2 CO 3 (n NaOH :n Na2CO3 =4:1) was prepared into 100 mL of deionized water and recorded as solution B.

[0197] (2) Solution A and solution B were simultaneously added dropwise to 100 mL of deionized water, pH = 8, stirred and aged at 60 ° C for 15 h, cooled to room temperature, filtered, washed with deionized water until neutral, dried at 80 ° C for 11 h, and calcined at 500 ° C for 4 h to obtain MgLaZr-Cl 0.5 catalyst.

[0198] Application Example 26

[0199] The process of synthesizing glycerol carbonate by urea method uses the catalyst of this comparative example, and other parameters are the same as those of Example 1. Finally, the conversion rate of glycerol obtained by gas chromatography analysis is 76.31%, and the selectivity of glycerol carbonate is 83.57%.

[0200] Comparative Example 5

[0201] The preparation method of the catalyst for synthesizing glycerol carbonate by urea method in this embodiment is different from that in Example 1 in that Ni:Al:Zr=3:0.7:0.3. 11.627 g Ni(NO 3 ) 2 6H 2 O, 3.5 g Al(NO 3 ) 3 9H 2 O, 1.716 g Zr(NO 3 ) 4 ·5H 2 O, specifically comprising the following steps:

[0202] (1) According to the ratio of Ni:Al:Zr=3:0.7:0.3, weigh 11.627g Ni(NO 3 ) 2 6H 2 O, 3.5 g Al(NO 3 ) 3 9H 2 O, 1.716 g Zr(NO 3 ) 4 ·5H 2 O and 1.558 g NaCl (n Cl- :n 金属 =0.5:1) Add 100 mL of deionized water and stir evenly, record as solution A. Weigh 8 g NaOH and 5.3 g Na 2 CO 3 (n NaOH :n Na2CO3 =4:1) was prepared into 100 mL of deionized water and recorded as solution B.

[0203] (2) Add solution A and solution B dropwise into 100 mL of deionized water simultaneously, maintain the pH at 8, stir and age at 60 °C for 15 h, cool to room temperature, carry out suction filtration, wash with deionized water until neutral, dry at 80 °C for 11 h, and calcine at 500 °C for 4 h to obtain NiAlZr-Cl 0.5 catalyst.

[0204] Application Example 27

[0205] The process of synthesizing glycerol carbonate by the urea method uses the catalyst of this comparative example, and other parameters are the same as those in Example 1. Finally, through gas chromatography analysis, the conversion rate of glycerol is 75.53%, and the selectivity of glycerol carbonate is 69.52%.

[0206] Comparative Example 6

[0207] The preparation method of the catalyst for synthesizing glycerol carbonate by the urea method in this example is different from that in Example 1 in that Ni:La:Zr = 3:0.7:0.3. Weigh 11.627 g of Ni(NO 3 ) 2 ·6H 2 O, 4.04 g of La(NO 3 ) 3 ·6H 2 O, 1.716 g of Zr(NO 3 ) 4 ·5H 2 O. Specifically, it includes the following steps:

[0208] (1) Weigh 11.627 g of Ni(NO 3 ) 2 ·6H 2 O, 4.04 g of La(NO 3 ) 3 ·6H 2 O, 1.716 g of Zr(NO 3 ) 4 ·5H 2 O and 1.558 g of NaCl (n Cl- :n 金属 = 0.5:1) and add them into 100 mL of deionized water and stir evenly, which is recorded as solution A. Weigh 8 g of NaOH and 5.3 g of Na 2 CO 3 (n NaOH :n Na2CO3 = 4:1) and dissolve them in 100 mL of deionized water, which is recorded as solution B.

[0209] (2) Solution A and solution B were simultaneously added dropwise to 100 mL of deionized water, pH = 8, stirred and aged at 60 ° C for 15 h, cooled to room temperature, filtered, washed with deionized water until neutral, dried at 80 ° C for 11 h, and calcined at 500 ° C for 4 h to obtain NiLaZr-Cl 0.5 catalyst.

[0210] Application Example 28

[0211] The process of synthesizing glycerol carbonate by urea method uses the catalyst of this comparative example, and other parameters are the same as those of Example 1. Finally, the conversion rate of glycerol obtained by gas chromatography analysis is 66.85%, and the selectivity of glycerol carbonate is 65.74%.

[0212] The acid-base site contents of Example 1 and Comparative Examples 1-6 were tested, and the specific results are shown in Table 5.

[0213] Table 5 Acid-base site content of catalyst

[0214]

[0215] It can be seen from Table 5 that ZnAlZr-Cl 0.5 It has the highest acidic site content (0.53mmol / g) and the highest basic site content (0.32mmol / g), which may be due to the ZnAlZr-Cl 0.5 A thinner layer structure is formed, thus exposing more acid-base sites.

[0216] Implementation effect example

[0217] The catalyst prepared by the present invention is recovered and the cycle performance is tested, and the specific steps are as follows:

[0218] (1) Catalyst recovery and treatment

[0219] The reaction mixture of Example 1 was added with 30 mL of methanol and mixed evenly, then centrifuged and washed three times, and dried in an oven at 80° C. for 11 h to obtain the recovered ZnAlZr-Cl 0.5 catalyst.

[0220] (2) Cyclic performance test of recovered catalyst

[0221] The recovered catalyst was used to repeat the experiment of catalyzing glycerol and urea to synthesize glycerol carbonate 5 times. The reaction conditions were the same as those in Example 1. The performance of the catalyst after 5 cycle experiments is shown in Table 6.

[0222] Table 6 Catalyst catalytic synthesis of glycerol carbonate cyclic reaction experimental results

[0223]

[0224]

[0225] In summary, the anion-modified mixed metal oxide catalyst prepared by the present invention for catalyzing the synthesis of glycerol carbonate from urea and glycerol introduces halogen ions as alkaline sites to activate the hydroxyl groups of glycerol during the reaction, while the metal ions act as acidic sites to activate the carbonyl groups of urea. The catalyst has a large specific surface area and abundant active sites, and can efficiently catalyze glycerol to prepare glycerol carbonate. The reaction process is simple and mild, the product selectivity is good, the catalyst is easy to separate, and it has good reusability, and has good application prospects in industry.

[0226] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a catalyst for synthesizing glycerol carbonate by urea process, characterized in that: The following steps are involved: (1) Dissolve Zn salt, Al salt, Zr salt and sodium halide in deionized water to obtain solution A; (2) Dissolve sodium hydroxide and anhydrous sodium carbonate in deionized water to obtain solution B; (3) Under stirring, solution A and solution B are added to deionized water, maintaining the pH value at 8, to obtain a mixed solution; the mixed solution is aged, washed to neutrality, dried, and calcined to obtain a catalyst for synthesizing glycerol carbonate by the urea method.

2. The method for preparing a catalyst for synthesizing glycerol carbonate by urea process according to claim 1, characterized in that: In step (1), Zn 2+ 、Al 3+ and Zr 4+ The molar ratio is (1-5):0.7:0.

3.

3. The method for preparing a catalyst for synthesizing glycerol carbonate by urea process according to claim 2, characterized in that: In step (1), Zn 2+ 、Al 3+ and Zr 4+ The molar ratio of the three metal ions to the halogen ions is 1:(0.1-3).

4. The method for preparing a catalyst for synthesizing glycerol carbonate by urea process according to any one of claims 1 to 3, characterized in that: The sodium halide in step (1) is any one of sodium fluoride, sodium chloride, sodium bromide and sodium iodide.

5. The method for preparing a catalyst for synthesizing glycerol carbonate by urea process according to claim 4, characterized in that: The molar ratio of sodium hydroxide to anhydrous sodium carbonate in step (2) is (2-5):

1.

6. The method for preparing the catalyst for synthesizing glycerol carbonate by urea process according to claim 5, characterized in that: In the step (3), the aging temperature is 60-100°C and the time is 10-20 h; the calcination temperature is 400-600°C and the time is 3-5 h.

7. A catalyst for synthesizing glycerol carbonate by urea process prepared by the preparation method according to claim 1.

8. Use of the catalyst for synthesizing glycerol carbonate by urea process according to claim 7 in synthesizing glycerol carbonate.

9. The use according to claim 8, characterized in that: The process conditions for synthesizing glycerol carbonate are as follows: glycerol and urea are mixed under a vacuum degree of 0.1 MPa, a catalyst is added, and glycerol carbonate is obtained through reaction.

10. The use according to claim 8 or 9, characterized in that: The molar ratio of glycerol to urea is (0.8-1.2):1; the mass of the catalyst is 6-12% of the urea; the reaction temperature is 120-150°C and the reaction time is 1-5 h.

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