A catalyst, preparation method and application thereof, and a reactive distillation preparation method of isosorbide

Abstract

The present invention relates to the field of isosorbide preparation, and discloses a catalyst, preparation method, and application thereof, as well as a method for preparing isosorbide by reactive distillation. The catalyst comprises a Group VIB metal oxide and at least one acidified Group IB, IVB, VB, and VIB metal oxide. The catalyst of the present invention has high catalytic activity and service life, stable catalytic performance, and is suitable for continuous production. Furthermore, the isosorbide obtained by the reactive distillation method of isosorbide prepared using the catalyst of the present invention has high purity, a stable process, and can achieve continuous reactive distillation.

Description

Technical Field

[0001] The present invention relates to the field of preparation of isosorbide, and further to a catalyst, a preparation method and application thereof, and a reactive distillation preparation method of isosorbide. Background Art

[0002] Isosorbide, as an important biomass-derived chemical, is a completely non-toxic green diol. It is not only widely used in medicine, surfactants and plastic additives, but also has very important significance in the field of new polymer materials.

[0003] The typical isosorbide production process involves adding the raw materials, solvent, and catalyst to a reactor, controlling the temperature and pressure, stirring, and heating the reaction for a specified time. After the reaction is complete, the materials enter a separation unit for post-processing, where the product is separated and purified through operations such as distillation, crystallization, and filtration. These production processes are characterized by their separation into a reaction unit and a post-processing unit, requiring significant equipment investment, complex operating procedures, and high energy consumption. This results in high production costs, limiting their widespread adoption.

[0004] Currently reported synthetic routes for isosorbide primarily utilize sorbitol as the raw material and solid or liquid acids as catalysts via catalytic dehydration. Solid acids primarily include molecular sieves, ion exchange resins, metal phosphates, and heteropolyacids. Due to their advantages, such as low material requirements for equipment, relatively simple product separation, and catalyst recyclability, solid acid dehydration catalysts have attracted attention and are poised to gradually replace liquid acid catalysts. However, challenges with catalyst performance and process methods have hindered large-scale industrialization.

[0005] CN 110563741A discloses a method for preparing isosorbide using a perfusion reactive distillation apparatus. This method uses solid sorbitol as the raw material, heats and melts it, and then simultaneously reacts and separates it in a perfusion reactive distillation apparatus loaded with a catalyst. However, the resulting product has a low purity of only 95-96%, which does not meet the high-purity requirements of the new materials field. Furthermore, the invention does not disclose the catalyst lifespan, leaving room for further improvement. Summary of the Invention

[0006] The present invention aims to address the drawbacks of existing isosorbide preparation processes, such as complex processes or low purity of the isosorbide product obtained through reactive distillation processes, by providing a catalyst, preparation method, and application thereof, as well as a method for preparing isosorbide by reactive distillation. The catalyst of the present invention has high catalytic activity and service life, stable catalytic performance, and is suitable for continuous production. Furthermore, the isosorbide obtained by the reactive distillation method of isosorbide using the catalyst of the present invention is highly pure, and the process is stable, enabling continuous reactive distillation.

[0007] SUMMARY OF THE INVENTION It is an object of the present invention to provide a catalyst comprising a Group VIB metal oxide and at least one acidified Group IB, IVB, VB and VIB metal oxide.

[0008] According to the present invention, the molar ratio of the total content of Group IB, IVB, VB, and VIB metal elements to the Group VIB metal elements in the catalyst can be selected within a wide range. In a preferred embodiment of the present invention, the molar ratio of the total content of Group IB, IVB, VB, and VIB metal elements to the Group VIB metal elements in the catalyst is (2-20):1, preferably (5-10):1.

[0009] According to the present invention, the selection range of the Group VIB metal oxide is relatively wide. In a preferred embodiment of the present invention, the Group VIB metal oxide is selected from metal oxides corresponding to at least one metal element selected from Fe, Co and Ni, preferably Fe.

[0010] According to the present invention, the Group IB, IVB, VB, and VIB metal oxides can be selected from a variety of sources. In a preferred embodiment of the present invention, the Group IB, IVB, VB, and VIB metal oxides are selected from metal oxides corresponding to at least one of niobium, zirconium, copper, and tungsten, and are preferably selected from niobium.

[0011] According to the present invention, the total content of the corresponding acid radicals in the acidified Group IB, IVB, VB, and VIB metal oxides relative to 1 g of the acidified Group IB, IVB, VB, and VIB metal oxides can be selected over a wide range. In a preferred embodiment of the present invention, the total content of the corresponding acid radicals in the acidified Group IB, IVB, VB, and VIB metal oxides relative to 1 g of the acidified Group IB, IVB, VB, and VIB metal oxides is 4-8 mmol, preferably 5-6 mmol.

[0012] According to the present invention, the acidified Group IB, IVB, VB, and VIB metal oxides can be prepared by various methods. In a preferred embodiment, the acidified Group IB, IVB, VB, and VIB metal oxides are obtained by mixing the corresponding metal oxide source with an acidifying agent and drying. Preferably, the mixing conditions include a temperature of 60-200°C, preferably 80-160°C, and a time of 6-24 hours. More preferably, the mixing is performed under reflux conditions.

[0013] According to the present invention, the acidulant can be selected from a variety of options. In a preferred embodiment of the present invention, the acidulant is selected from at least one of sulfuric acid, methanesulfonic acid, phosphoric acid and oxalic acid, preferably sulfuric acid or phosphoric acid.

[0014] According to the present invention, the source of Group IB, IVB, VB and VIB metal oxides can be selected from a variety of sources. In a preferred embodiment of the present invention, the source of Group IB, IVB, VB and VIB metal oxides is selected from oxides and / or hydroxides of the corresponding metal elements.

[0015] According to the present invention, the molar ratio of the total amount of the Group IB, IVB, VB, and VIB metal oxide source to the acidulant can be selected within a wide range. In a preferred embodiment of the present invention, the molar ratio of the total amount of the Group IB, IVB, VB, and VIB metal oxide source to the acidulant is (0.5-3):1, preferably (1-2):1.

[0016] According to the present invention, the average particle size of the catalyst can be selected in a wide range. In a preferred embodiment of the present invention, the average particle size of the catalyst is 100-800 μm, preferably 400-600 μm.

[0017] In a preferred embodiment of the present invention, the catalyst is obtained by mixing acidified at least one of IB, IVB, VB and a Group VIB metal oxide with a Group VIB metal element source and calcining the mixture.

[0018] A second object of the present invention is to provide a method for preparing the catalyst described above, comprising mixing and calcining at least one of acidified Group IB, IVB, VB and VIB metal oxides with a Group VIIIB metal element source to obtain the catalyst.

[0019] According to the present invention, the calcination conditions have a wide range of selections. In a preferred embodiment of the present invention, the calcination conditions include: a temperature of 200-600°C, preferably 300-500°C.

[0020] According to the present invention, the calcination time condition has a wide range of selection. In a preferred embodiment of the present invention, the calcination time is 6-20 hours, preferably 8-12 hours.

[0021] In a preferred embodiment of the present invention, the preparation method further comprises the step of crushing the obtained product after roasting.

[0022] In a more preferred embodiment of the present invention, the solid catalyst is an acidified metal oxide, such as niobium oxide, zirconium oxide, copper oxide, tungsten oxide, etc. Niobium oxide is preferred. The catalyst is prepared by first mixing the corresponding oxide or hydroxide with at least one of an acid, such as sulfuric acid, methanesulfonic acid, phosphoric acid, or oxalic acid. The mixture is stirred at reflux for 8-12 hours at 60-200°C, then evaporated to dryness, and further dried to obtain the acidified metal oxide. Auxiliary ingredients, such as ferric chloride and ferric sulfate, are then added, followed by calcination and pulverization at 200-600°C to obtain the desired catalyst.

[0023] A third object of the present invention is to provide a use of the catalyst described above or the catalyst prepared by the preparation method described above in the preparation of isosorbide.

[0024] A fourth object of the present invention is to provide a method for preparing isosorbide by reactive distillation, comprising contacting a hexose with the catalyst described above or the catalyst prepared by the preparation method described above, and simultaneously performing a hexose dehydration reaction and distillation.

[0025] According to the present invention, the hexose can be selected from a variety of options. In a preferred embodiment of the present invention, the hexose is selected from sorbitol and / or 1,4-anhydrosorbitol.

[0026] According to the present invention, the mass ratio of the catalyst to hexose has a wide selection range. In a preferred embodiment of the present invention, the mass ratio of the catalyst to hexose is (1-10):100, preferably (3-5):100.

[0027] According to the present invention, the reactive distillation conditions have a wide range of selection. In a preferred embodiment of the present invention, the reactive distillation conditions include: a temperature of 130-200°C, preferably 160-180°C.

[0028] According to the present invention, the time range for reactive distillation is relatively wide. In a preferred embodiment of the present invention, the time is 4-10 hours, preferably 5-7 hours.

[0029] According to the present invention, the vacuum degree conditions for reactive distillation can be selected in a wide range. In a preferred embodiment of the present invention, the vacuum degree is 100-500Pa, preferably 200-300Pa.

[0030] According to the present invention, the reflux ratio of reactive distillation can be selected in a wide range. In a preferred embodiment of the present invention, the reflux ratio is 2-8, preferably 3-5.

[0031] According to the present invention, the number of distillation plates for reactive distillation can be selected in a wide range. In a preferred embodiment of the present invention, the number of distillation plates is 10-40, preferably 20-30.

[0032] In a more preferred embodiment of the present invention, the conditions for reactive distillation include: temperature of 130-200°C, preferably 160-180°C; time of 4-10 hours, preferably 5-7 hours; vacuum degree of 100-500 Pa, preferably 200-300 Pa; reflux ratio of 2-8, preferably 3-5; and number of distillation plates of 10-40, preferably 20-30.

[0033] In a further more preferred embodiment of the present invention, the reactive distillation is carried out in stages. The specific conditions include: first reactive distillation at 130-140°C for 2-4 hours, then heating to 145-165°C and continuing reactive distillation until no more water is produced.

[0034] In a preferred embodiment of the present invention, the water and isosorbide products generated by the reactive distillation are taken out from the top of the tower.

[0035] In a preferred embodiment of the present invention, the reactive distillation preparation method further comprises the step of dehydrating the product obtained by reactive distillation; preferably, dehydration is performed using a dehydration tower; further preferably, the dehydration conditions of the dehydration tower include: a temperature of 100-120°C, preferably 100-110°C.

[0036] In a preferred embodiment of the present invention, the reactive distillation preparation method further comprises a step of purifying the obtained isosorbide product after dehydration; preferably, this step is performed by recrystallization. Further preferably, the solvent used for recrystallization is selected from at least one of ethyl acetate, isopropanol, acetone, and n-heptane. More preferably, the distillation product is added to ethyl acetate, isopropanol, acetone, or n-heptane, heated to dissolve, then the temperature is lowered. After a certain period of time, seed crystals are added, and the product slowly precipitates. After filtration and washing, a very high purity product is obtained, with an HPLC test result of over 99.5%.

[0037] In a more preferred embodiment of the present invention, solid sorbitol or sorbitol aqueous solution is used as a raw material, and the modified metal oxide of the present invention is used as a catalyst to synthesize isosorbide through a one-step or multi-step dehydration reaction. The corresponding reaction formula is shown below:

[0038]

[0039] In a more preferred embodiment of the present invention, the present invention uses sorbitol as a raw material and a modified acidified metal oxide as a catalytic dehydrating agent, preferably adopting a reactive distillation method, through a one-step or multi-step dehydration reaction, to synthesize an isosorbide product. Specifically: adopt reactive distillation technology, use sorbitol as a reaction raw material, use the modified metal oxide of the present invention as a catalyst, couple the reaction and post-treatment in one device, take the catalyst of the product and the reaction raw material mass ratio of (0.5-5):100 and add it to a reactor equipped with a distillation column, the distillation column has a number of plates of 10-40, and the tower is equipped with fillers, then add the reaction raw materials, start stirring, slowly heat to a certain temperature, then start vacuum, react for 4-10 hours, and the generated water is collected through the tower top. As the concentration of the reactor intermediate product and the isosorbide product increases, the reaction temperature further increases. At this time, the main products extracted from the tower top are water and the isosorbide product. After passing through the dehydration tower, an isosorbide product with a purity of more than 98% can be obtained, and a product with a purity of 99.5% can be obtained by further recrystallization.

[0040] According to the above method, the product is separated by distillation while the reaction is carried out. On the one hand, the generated products can be separated in time, thereby improving production efficiency. On the other hand, the process flow is simplified, equipment investment and energy consumption are reduced, and production costs are also reduced. At the same time, the catalyst of the present invention has a long service life and is suitable for continuous production.

[0041] Isosorbide contains two hydroxyl groups in its molecular structure, has a special stereostructure, and is a green biomass-derived product. Therefore, it has a wide range of applications in medicine, new materials, and organic synthesis.

[0042] Compared with the prior art, the present invention has the following advantages:

[0043] (1) The catalyst of the present invention has high catalytic activity and service life, stable catalytic performance, and is suitable for continuous production.

[0044] (2) The preparation method of the catalyst of the present invention is simple, low-cost and controllable, and has high application value.

[0045] (3) The isosorbide obtained by the reactive distillation preparation method of isosorbide using the catalyst of the present invention has high purity and a stable process, and can achieve continuous reactive distillation.

[0046] (4) The present invention carries out the isosorbide synthesis reaction and product post-treatment in one device, which has a small footprint and reduces equipment investment. The reaction and separation use integrated heating, which reduces energy consumption. The generated products can be separated in a timely manner, which improves production efficiency and thus reduces production costs. The catalyst has a long life and is suitable for continuous production and industrial application. The isosorbide synthesized by the present invention can be widely used in the fields of new materials, medicine and organic synthesis. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is the HPLC (high performance liquid chromatography) chart of the isosorbide product in Example 1. DETAILED DESCRIPTION

[0048] The present invention will be described in detail below with reference to specific drawings and embodiments. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art to the present invention based on the contents of the present invention still fall within the scope of protection of the present invention.

[0049] In the following examples, the content of the corresponding acid radical in 1 g of the acidified metal oxide was determined by titration.

[0050] In the following examples, the purity of isosorbide was detected by HPLC (high performance liquid chromatography).

[0051] In the following examples, the yield determination method of the isosorbide product is as follows:

[0052]

[0053]

[0054]

[0055] Throughout, n refers to the corresponding molar amount, n sorbitol initial Refers to the amount of sorbitol raw material; n sorbitol in product Refers to the sorbitol in the product; n isosorbide refers to isosorbide; C refers to conversion; S refers to selectivity; Y sosorbide Refers to the yield of isosorbide.

[0056] In the following examples, unless otherwise specified, all raw materials used are commercially available.

[0057] Preparation Example 1

[0058] First, 10 g of niobium oxide was mixed with 50% by mass concentration sulfuric acid in a molar ratio of 1:1, stirred at 80° C. for 8 h, then evaporated to dryness at 100° C., and further dried at 120° C. for 8 h to obtain acidified niobium oxide. The acid radical content in 1 g of the acidified niobium oxide (metal oxide) was determined as shown in Table 1.

[0059] The acidified niobium oxide and ferric chloride were sampled and mixed in an element molar ratio of Nb:Fe=6:1, calcined at a high temperature of 450°C for 6 hours, and then crushed to obtain the desired catalyst.

[0060] Preparation Example 2

[0061] First, 10 g of niobium oxide was mixed with 30% by mass phosphoric acid in a molar ratio of 1:2, stirred at 120° C. for 8 h, and then the water was evaporated to dryness, followed by further drying at 200° C. for 8 h to obtain acidified niobium oxide. The acid radical content in 1 g of the acidified niobium oxide (metal oxide) was determined as shown in Table 1.

[0062] 10 g of acidified niobium oxide and ferric chloride were sampled and mixed according to the element molar ratio of Nb:Fe=4:1, calcined at a high temperature of 500°C for 6 hours, and then crushed to obtain the desired catalyst.

[0063] Preparation Example 3

[0064] First, 10 g of copper oxide was mixed with 50% mass concentration sulfuric acid in a molar ratio of 1:1, stirred at 80°C for 8 hours, then evaporated to dryness at 100°C, and further dried at 120°C for 8 hours to obtain acidified copper oxide. The acid radical content in 1 g of the acidified metal oxide was determined as shown in Table 1.

[0065] The acidified ketone oxide and ferric chloride were sampled and mixed according to the element molar ratio of Cu:Fe=10:1, calcined at a high temperature of 450°C for 6 hours, and then crushed to obtain the desired catalyst.

[0066] Preparation Example 4

[0067] The catalyst was prepared according to the method of Preparation Example 1, except that the ferric chloride in Preparation Example 1 was replaced by an equal molar amount of hydrated nickel chloride.

[0068] Preparation Example 5

[0069] The catalyst was prepared according to the method of Preparation Example 1, except that the ferric chloride in Preparation Example 1 was replaced by an equimolar amount of cobalt chloride.

[0070] Preparation Comparative Example 1

[0071] The catalyst was prepared according to the method of Preparation Example 1, except that ferric chloride was not added during the preparation process:

[0072] First, 10 g of niobium oxide (or hydroxide) was mixed with 50 wt% sulfuric acid in a molar ratio of 1:1, stirred at 80°C for 8 hours, then evaporated to dryness at 100°C, and further dried at 120°C for 8 hours to obtain acidified niobium oxide;

[0073] Then it is calcined at a high temperature of 450°C for 6 hours and then crushed to obtain the desired catalyst.

[0074] Preparation Comparative Example 2

[0075] The catalyst was prepared according to the method of Preparation Example 1, except that ferric chloride was replaced by an equimolar amount of zinc chloride:

[0076] First, 10 g of niobium oxide (or hydroxide) was mixed with 50% sulfuric acid in a molar ratio of 1:1, stirred at 80°C for 8 hours, then evaporated to dryness at 100°C, and further dried at 120°C for 8 hours to obtain acidified niobium oxide;

[0077] The acidified niobium oxide is mixed with zinc chloride, calcined at a high temperature of 450°C for 6 hours, and then crushed to obtain the desired catalyst.

[0078] Preparation Comparative Example 3

[0079] The catalyst was prepared according to the method of Preparation Example 1, except that ferric chloride and niobium oxide were added simultaneously.

[0080] First, 10g of niobium oxide, ferric chloride (ferric chloride is sampled according to the element molar ratio of Nb:Fe=6:1) and 50% mass concentration of sulfuric acid according to the sulfuric acid metal element molar ratio of 1:1 are mixed, stirred at 80°C for 8h, and then the water is evaporated at 100°C and further dried at 120°C for 8h to obtain acidified niobium oxide; then, it is calcined at a high temperature of 450°C for 6h and then crushed to obtain the desired catalyst.

[0081] Table 1

[0082]

[0083] Example 1

[0084] 100 g of solid sorbitol was added to a reactor with a distillation column (with 20 plates), 3 g of the catalyst in Preparation Example 1 was added as a dehydration catalyst, heated to 110° C., stirred, evacuated to a vacuum degree of 200 Pa, then heated to 130° C., and reacted for 3 h. Most of the generated water was removed from the top, and then the temperature was further raised to 150° C., while controlling the reflux ratio to 3, and the product at the top was collected. HPLC analysis showed that the purity of the top product was greater than 98%. The obtained product passed through a dehydration tower (temperature of 110° C., with a dehydration tower plate number of 10), and the HPLC purity was 99.5%. Figure 1. According to calculation, the yield of isosorbide after dehydration is 70%.

[0085] Example 2

[0086] 100 g of solid sorbitol was added to a reactor equipped with a distillation column (with 20 plates), 5 g of the catalyst prepared in Preparation Example 2 was added as a dehydration catalyst, and the mixture was heated to 110° C., stirred, and evacuated to a vacuum of 300 Pa. The temperature was then raised to 130° C. and allowed to react for 4 h. Most of the generated water was removed, and the temperature was then further raised to 150° C. while controlling the reflux ratio to 5. The product at the top was collected, and the purity of the top product was greater than 98% as determined by HPLC. The product thus obtained passed through a dehydration column (with a temperature of 110° C. and a dehydration column with 10 plates) and had an HPLC purity of 99.5%.

[0087] Example 3

[0088] 100 g of solid sorbitol was added to a reactor equipped with a distillation column (with 20 plates), 3 g of the catalyst in Preparation Example 3 was added as a dehydration catalyst, and the mixture was heated to 110° C., stirred, and evacuated to a vacuum degree of 200 Pa. The temperature was then raised to 135° C. and allowed to react for 3 h. Most of the generated water was removed, and the mixture was then further heated to 160° C. while controlling the reflux ratio to 6. The product at the top was collected, and the purity of the top product was 98% as determined by HPLC. The obtained product passed through a dehydration tower (with a temperature of 110° C. and a dehydration tower with 10 plates) with an HPLC purity of 99%. After further recrystallization using ethyl acetate as a solvent, the product purity reached 99.5%.

[0089] Example 4

[0090] Isosorbide was prepared according to the method of Example 1, except that the catalyst in Preparation Example 4 was used instead of the catalyst in Preparation Example 1 used in Example 1.

[0091] Example 5

[0092] Isosorbide was prepared according to the method of Example 1, except that the catalyst in Preparation Example 5 was used instead of the catalyst in Preparation Example 1 used in Example 1.

[0093] Comparative Example 1

[0094] The method of Example 1 was followed, except that the catalyst used was replaced by the catalyst in Comparative Example 1.

[0095] The yield of isosorbide obtained was 60%.

[0096] Comparative Example 2

[0097] The method of Example 1 was followed, except that the catalyst used was replaced by the catalyst in Comparative Example 2. The yield of isosorbide obtained was only 52%.

[0098] Comparative Example 3

[0099] The method of Example 1 was followed, except that the catalyst used was replaced by the catalyst in Comparative Example 3. The yield of isosorbide obtained was only 49%.

[0100] Stability test

[0101] The catalysts recovered from Examples 1-5 and Comparative Examples 1-3 were used to prepare 5 batches of isosorbide according to the method of isosorbide synthesis Example 1. The purity and yield of the final batch of isosorbide are shown in Table 2.

[0102] Table 2

[0103] catalyst Purity of isosorbide product / % Yield of isosorbide / % Preparation Example 1 99.5 69 Preparation Example 2 99.5 63 Preparation Example 3 99.5 64 Preparation Example 4 99 56 Preparation Example 5 99 52 Preparation Comparative Example 1 99 42 Preparation Comparative Example 2 99 39 Preparation Comparative Example 3 99 35

[0104] As can be seen from Table 2, after five cycles of reaction and distillation, the catalyst product obtained by the present invention has stable yield and purity, while the catalysts prepared in Comparative Examples 1-3 have poor stability.

[0105] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation of the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein. On the contrary, the present invention can be extended to all other methods and applications with the same function.

[0106] All publications, patent applications, patents, and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings conventionally understood by those skilled in the art. In the event of conflict, the definitions in this specification shall prevail.

[0107] When this specification uses the prefix "well known to those skilled in the art", "prior art" or similar terms to introduce materials, substances, methods, steps, devices or components, the objects introduced by the prefix include those commonly used in the art when this application is filed, but also include those that are not commonly used at present but will become generally recognized in the art to be suitable for similar purposes.

[0108] The endpoints and any values ​​of the ranges disclosed in this application document are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and a separate point value, and the separate point values ​​can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be considered as specifically disclosed in this article. Hereinafter, in principle, each technical solution can be combined with each other to obtain a new technical solution, which should also be considered as specifically disclosed in this article.

[0109] In the context of this specification, any matters or items not mentioned are directly applicable to those known in the art without any changes except those explicitly stated.

[0110] Moreover, any embodiment described herein may be freely combined with one or more other embodiments described herein, and the technical solutions or technical ideas thus formed shall be deemed as part of the original disclosure or original record of the present invention, and shall not be regarded as new content that has not been disclosed or anticipated herein, unless a person skilled in the art considers that the combination is obviously unreasonable.

Claims

1. A catalyst comprising a Group VIB metal oxide and at least one acidified Group IB, IVB, VB and VIB metal oxide; The molar ratio of the total content of the metal elements of Groups IB, IVB, VB and VIB to the metal elements of Group VIIIB in the catalyst is (2-20):1; The Group VIII B metal oxide is selected from metal oxides corresponding to at least one metal element selected from Fe, Co and Ni; The metal oxides of Groups IB, IVB, VB and VIB are selected from metal oxides corresponding to at least one metal element selected from niobium, zirconium, copper and tungsten; The catalyst is obtained by mixing at least one of acidified Group IB, IVB, VB and VIB metal oxides with a Group VIIIB metal element source and calcining the mixture; The acidifying agent used for acidification is selected from at least one of sulfuric acid, methanesulfonic acid, phosphoric acid and oxalic acid; The total content of the corresponding acid radicals in the acidified Group IB, IVB, VB and VIB metal oxides is 4-8 mmol relative to 1 g of the acidified Group IB, IVB, VB and VIB metal oxides; The average particle size of the catalyst is 100-800 μm.

2. The catalyst according to claim 1, characterized in that: The molar ratio of the total content of Group IB, IVB, VB and VIB metal elements to the Group VIIIB metal elements in the catalyst is (5-10):

1.

3. The catalyst according to claim 1, characterized in that: The total content of corresponding acid radicals in the acidified Group IB, IVB, VB and VIB metal oxides is 5-6 mmol relative to 1 g of the acidified Group IB, IVB, VB and VIB metal oxides.

4. The catalyst according to claim 1, characterized in that: The acidified Group IB, IVB, VB and VIB metal oxides are obtained by mixing the corresponding metal oxide source with an acidifying agent and drying.

5. The catalyst according to claim 4, characterized in that: The mixing conditions include: a temperature of 60-200° C.; and / or a mixing time of 6-24 hours.

6. The catalyst according to claim 5, characterized in that: The mixing conditions include: a temperature of 80-160°C.

7. The catalyst according to claim 4, characterized in that: The source of Group IB, IVB, VB and VIB metal oxides is selected from oxides and / or hydroxides of the corresponding metal elements; and / or, The molar ratio of the total amount of the Group IB, IVB, VB and VIB metal oxide sources to the acidifying agent is (0.5-3):

1.

8. The catalyst according to claim 4, characterized in that: The acidifying agent is selected from sulfuric acid or phosphoric acid; and / or, The molar ratio of the total amount of the Group IB, IVB, VB and VIB metal oxide sources to the acidifying agent is (1-2):

1.

9. The catalyst according to claim 1, characterized in that: The average particle size of the catalyst is 400-600 μm.

10. A method for preparing the catalyst according to any one of claims 1 to 9, comprising mixing at least one of acidified Group IB, IVB, VB and VIB metal oxides with a Group VIB metal source and calcining the mixture to obtain the catalyst.

11. The preparation method according to claim 10, characterized in that: The calcination conditions include: a temperature of 200-600°C; and / or a time of 6-20 hours; and / or, The preparation method further comprises the step of pulverizing the obtained product after roasting.

12. The preparation method according to claim 10, characterized in that: The calcination conditions include: a temperature of 300-500° C.; and / or a calcination time of 8-12 hours.

13. Use of the catalyst according to any one of claims 1 to 9 or the catalyst prepared by the preparation method according to any one of claims 10 to 12 in the preparation of isosorbide.

14. A method for preparing isosorbide by reactive distillation, comprising contacting a hexose with the catalyst according to any one of claims 1 to 9 or the catalyst prepared by the preparation method according to any one of claims 10 to 12, and simultaneously performing a dehydration reaction and a rectification of the hexose.

15. The reactive distillation preparation method according to claim 14, characterized in that: The hexose is selected from sorbitol and / or 1,4-anhydrosorbitol; and / or, The mass ratio of the catalyst to hexose is (1-10):

100.

16. The reactive distillation preparation method according to claim 14, characterized in that: The mass ratio of the catalyst to hexose is (3-5):

100.

17. The reactive distillation preparation method according to claim 14, characterized in that: The conditions for reactive distillation include: a temperature of 130-200°C; and / or, time is 4-10h; and / or, the vacuum degree is 100-500Pa; and / or, the reflux ratio is 2-8; and / or, The number of distillation plates is 10-40.

18. The reactive distillation preparation method according to claim 14, characterized in that: The conditions for reactive distillation include: a temperature of 160-180°C; and / or, time is 5-7h; and / or, the vacuum degree is 200-300Pa; and / or, the reflux ratio is 3-5; and / or, The number of distillation plates is 20-30.

19. The reactive distillation preparation method according to claim 17, characterized in that: The conditions of reactive distillation include: first reactive distillation at 130-140° C. for 2-4 hours, and then heating to 145-165° C. to continue reactive distillation.

20. The reactive distillation preparation method according to any one of claims 14 to 19, characterized in that: The water and isosorbide products generated by the reactive distillation are taken out from the top of the tower; and / or, The reactive distillation preparation method further comprises the step of dehydrating the product obtained by reactive distillation.

21. The reactive distillation preparation method according to any one of claims 14 to 19, characterized in that: The reactive distillation preparation method further comprises the step of dehydrating the product obtained by reactive distillation; the dehydration is carried out using a dehydration tower.

22. The reactive distillation preparation method according to any one of claims 14 to 19, characterized in that: The reactive distillation preparation method further comprises the step of dehydrating the product obtained by reactive distillation; Dehydration is carried out using a dehydration tower. The conditions for dehydration in the water tower include: The temperature is 100-120℃.

23. The reactive distillation preparation method according to any one of claims 14 to 19, characterized in that: The reactive distillation preparation method further comprises the step of dehydrating the product obtained by reactive distillation; Dehydration is carried out using a dehydration tower. The conditions for dehydration in the water tower include: The temperature is 100-110℃.

24. The reactive distillation preparation method according to any one of claims 14 to 19, characterized in that: The reactive distillation preparation method further comprises the step of purifying the obtained isosorbide product after dehydration.

25. The reactive distillation preparation method according to any one of claims 14 to 19, characterized in that: The reactive distillation preparation method further comprises the step of purifying the obtained isosorbide product after dehydration, wherein the step is carried out by recrystallization.

26. The reactive distillation preparation method according to claim 25, characterized in that: The solvent used for recrystallization is selected from at least one of ethyl acetate, isopropanol, acetone and n-heptane.

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