Method for producing delta-valerolactone through catalytic dehydrogenation of 1, 5-pentanediol, catalyst and preparation method of catalyst

Abstract

The invention relates to the field of cyclic lactone production, in particular to a method for producing delta-valerolactone through catalytic dehydrogenation of 1, 5-pentanediol, a catalyst and a preparation method of the catalyst. The catalyst is a dehydrogenation-cyclization functional catalyst, the composition of the dehydrogenation-cyclization functional catalyst is CuO / ZnO-Al2O3-La2O3, the active component is CuO and a composite oxide carrier ZnO-Al2O3-La2O3, the pressure of H2 in the dehydrogenation conversion process is 0.05 MPa, and the temperature is 230-240 DEG C. The invention further discloses a preparation method of the catalyst. Due to the adoption of the composite carrier copper-based catalyst, directional catalytic conversion of 1, 5-pentanediol can be realized under the conditions that the H2 pressure is 0.05 MPa and the temperature is 230-240 DEG C. The method can be used for continuous gas phase fixed beds and other reactors, and efficient catalytic conversion of 1, 5-pentanediol is achieved. The catalyst has the advantages of stable property, simple separation process and industrial production value.

Description

Technical Field

[0001] The invention relates to the field of cyclic lactone production, and in particular to a method for producing delta-valerolactone by catalytic dehydrogenation of 1,5-pentanediol, a catalyst and a method for preparing the catalyst. Background Art

[0002] δ-Valerolactone is a cyclic lactone compound with a molecular weight of 100 and a boiling point of 230°C. It is a colorless or light yellow liquid, slightly soluble in water, miscible with ethanol and ether, and a high boiling point solvent. Since the structure of δ-valerolactone is widely present in compounds with biological and optical activity, it can be used in the field of medicine. δ-valerolactone itself is easy to polymerize and can also form polylactide with other compounds. The synthesized copolymer has good biocompatibility and biodegradability. In recent years, the biodegradability of its polymer has promoted its wide application in environmental protection and medicine, making its synthesis as a monomer increasingly important.

[0003] In recent years, many research teams have explored the possibility of a series of new technologies for the synthesis of δ-valerolactone, as well as new technologies for improving traditional process catalysts. For example, as described in Chinese patent CN 109651318, a new method for generating δ-valerolactone by isomerization and addition cyclization of alkyl acetate and propylene oxide using lithium phosphate / alumina as catalysts. At 180-250°C and ~0.5MPa, alkyl acetate and propylene oxide can be efficiently converted into δ-valerolactone, with a δ-valerolactone selectivity of about 95% (based on propylene oxide). The propylene oxide process has problems such as the loss of active components such as lithium phosphate and complex catalyst preparation, and is in the laboratory research stage.

[0004] CN 109956921 introduces a new method for preparing δ-valerolactone by oxidative cracking of 1,6-hexanediol. Air and / or oxygen are used as oxygen sources, the catalyst is one or more of CuO / MnO2, VOx / MnO2, CeOx / MnO2, CoOx / MnO2, NiO / MnO2, and the solvent is acetonitrile, dioxane, tert-butyl alcohol, tert-amyl alcohol, toluene, p-xylene, etc. First, the catalyst, 1,6-hexanediol, and solvent are added to the reactor, and then the oxidant is slowly added. At 30-150°C, 0.1-5MPa, and 0.5-48 hours, the hexanediol is oxidatively cracked into δ-valerolactone. The hexanediol oxidative cracking process has the disadvantages of carbon release, low material balance, and explosion hazards, and is in the laboratory research stage.

[0005] CN 111484464 and CN 111548333 report a new method for preparing δ-valerolactone by carbonylation of tetrahydrofuran. Tetrahydrofuran and carbon monoxide are used as raw materials, and the catalyst is small-grained ZSM-5 or H-MOR molecular sieve; 0.5g of catalyst is loaded in a reaction tube with an inner diameter of 10mm and a length of 40cm, and the reaction temperature is 90-180℃ and 1-5MPa. The conversion rate of tetrahydrofuran is 8-18%, and the selectivity of δ-valerolactone is 94-99%. The tetrahydrofuran carbonylation process has the problem of δ-valerolactone oligomers blocking the pores of the molecular sieve, and is still in the laboratory stage.

[0006] Chinese patent CN 101157677 introduces a method for oxidizing 1,5-pentanediol to generate δ-valerolactone using a supported nano Au / TiO2 gold catalyst. 10-40 ml of tributyl phosphate as a solvent, 0.8 g of 1,5-pentanediol and 0.188-1.5 g of supported nano gold catalyst are added to an autoclave, 0.8-1.3 MPa of air is filled in, the temperature is controlled at 80-160°C, and the reaction is performed for 1-24 hours to obtain a δ-valerolactone selectivity of about 42%. The process for preparing δ-valerolactone by oxidizing pentanediol with air uses molecular oxygen, which results in low δ-valerolactone selectivity and potential safety hazards, limiting its widespread use.

[0007] Chinese patent CN 103980241 reports that 1,5-pentanediol is used for catalytic dehydrogenation to generate δ-valerolactone, and the catalyst is composed of 15-35% copper, 0.2-2% silver, 1-5% rare earth, and 20-60t% carrier. This process route requires first dehydrating 1,5-pentanediol through a drying tower to reach a water content of less than 0.05%; then mixing hydrogen with the dried 1,5-pentanediol and entering the vaporizer; finally, at about 0.1MPa and 230-270℃, 1,5-pentanediol is dehydrogenated to δ-valerolactone. This patented technology adds a dehydration section in the drying tower, which increases equipment investment and operating costs.

[0008] CN 106674173 introduces a dehydrogenation catalyst for 1,5-pentanediol and a method for producing δ-valerolactone. The catalyst is prepared by an impregnation method, the carrier is a layered double metal hydroxide modified alumina, and the active component is copper. The carrier is prepared by the following steps: adding alumina and an alkaline solution to a reactor, staying at 70-100°C for 10-48h; then, adding a magnesium nitrate solution, heating to 110-150°C, keeping for 10-48h, washing with water, drying, and roasting. Under the conditions of 170-250°C, ~0.1MPa, and a copper-based catalyst, the yield of 1,5-pentanediol converted to δ-valerolactone reaches about 98 or more. The 1,5-pentanediol dehydrogenation technology has the problems of long catalyst preparation steps, preparing copper active components by an impregnation method, and easy sintering of copper.

[0009] German BASF's US 8466299 B2 patent reports on the gas-phase catalytic dehydrogenation technology of 1,5-pentanediol. Using rare earth Ce, Yb, and Lu to modify CuO / SiO2 catalyst, the conversion rate of 1,5-pentanediol is about 99% and the selectivity of δ-valerolactone is about 95% under the conditions of reaction temperature of 260-350℃ and 0.05-1MPa. The patent for 1,5-pentanediol dehydrogenation has problems such as high reaction temperature, copper active components, and easy sintering.

[0010] At present, the industry mainly uses 1,5-pentanediol catalytic dehydrogenation to produce δ-valerolactone, or uses cyclopentanone oxidation Baeyer-Villiger reaction to prepare δ-valerolactone. The Baeyer-Villiger oxidation production process of cyclopentanone uses peroxide oxidants, such as peroxybenzoic acid, anhydrous peracetic acid, etc. Due to the organic acid byproduct of peroxide acid, it is necessary to use alkaline post-treatment such as sodium hydroxide and sodium carbonate, which increases production costs and environmental pollution. In addition, due to the presence of peroxide, risks such as combustion and explosion are prone to occur. In fact, the Baeyer-Villiger method for preparing δ-valerolactone is rarely used in industry. In addition, the use of petrochemical technology to convert the synthetic raw material cyclopentanone in multiple steps leads to high prices and lack of market competitiveness.

[0011] In industry, corn cobs, bagasse and other agricultural and forestry wastes are used as raw materials to produce furfural through hydrolysis and refining.

[0012] In 2023, Henan Haosen Biomaterials Co., Ltd. completed and put into production a new 20,000-ton furfuryl alcohol hydrogenation plant to produce pentanediol, and co-produced several thousand tons of biomass-based 1,5-pentanediol. Its market price has dropped to a reasonable low level, making the use of biomass-based 1,5-pentanediol catalytic dehydrogenation to produce δ-valerolactone have a clear price advantage.

[0013] Dehydrogenation of 1,5-pentanediol to δ-valerolactone. After the aldehyde condensation reaction, 1,5-pentanediol is first converted into 5-hydroxyvaleraldehyde, and the hydroxyl group after condensation is dehydrogenated again to generate δ-valerolactone. The reaction path is as follows: Figure 1 shown. Summary of the invention

[0014] Purpose of the invention: To provide a method for producing δ-valerolactone by catalytic dehydrogenation of 1,5-pentanediol with better effect, as well as a catalyst and a method for preparing the catalyst. For specific purposes, see the multiple substantial technical effects in the specific implementation section.

[0015] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0016] The catalyst of the method for producing delta-valerolactone by catalytic dehydrogenation of 1,5-pentanediol is characterized in that the catalyst is a dehydrogenation-cyclization functional catalyst, the dehydrogenation-cyclization functional catalyst composition is CuO / ZnO-Al2O3-La2O3, the active component is CuO, the composite oxide carrier is ZnO-Al2O3-La2O3, the H2 pressure in the dehydrogenation conversion process is 0.05MPa, and the temperature is 230-240°C.

[0017] A further technical solution of the present invention is that the dehydrogenation-cyclization functional catalyst has the following components in parts by weight: CuO content is 20-35 parts, ZnO content is 45-60 parts, Al2O3 content is 15-23 parts, and La2O3 content is 2-7 parts, and the above units are parts by weight.

[0018] A further technical solution of the present invention is that the contents of the components are: CuO content is 22-27%, ZnO content is 50-54%, Al2O3 content is 18-22%, and La2O3 content is 3-5%.

[0019] The method for preparing a catalyst for the method for producing delta-valerolactone by catalytic dehydrogenation of 1,5-pentanediol is characterized in that:

[0020] The method is prepared by co-current co-precipitation, wherein the metal salt solutions of the active components are first prepared in the required proportions;

[0021] Then prepare a precipitant: a mixed alkaline solution with a molar ratio of sodium hydroxide to sodium carbonate of 6;

[0022] Then, at the temperature and pH value, the metal salt solution and the mixed alkaline solution of sodium hydroxide / sodium carbonate are added dropwise to the precipitation kettle in parallel, stirred for 1 hour, heated to 80°C and aged for 20 hours, filtered, washed, dried and calcined to obtain the desired dehydrogenation catalyst.

[0023] A further technical solution of the present invention is that the specific catalyst preparation comprises the following steps:

[0024] (1) Prepare 1 mol / L copper nitrate, zinc nitrate, aluminum nitrate, and lanthanum nitrate solutions, stir and dissolve them, and mix them evenly to obtain a mixed acidic salt solution.

[0025] (2) Prepare a mixed alkali solution with a molar ratio of sodium hydroxide to sodium carbonate of 6:1 and a solution of about 1 mol / L as a precipitant.

[0026] (3) Add the acid solution and alkali solution prepared in (1) and (2) to the precipitation kettle in parallel and perform co-precipitation, stir vigorously, and control the precipitation temperature to 40-45°C and pH value to 10. The strong stirring here refers to: 500r / min in the laboratory; 100r / min or more in the workshop anchor frame stirring.

[0027] (4) Continue stirring, raise the temperature to 80°C, and age for 20 hours.

[0028] (5) Filter and wash to remove residual sodium ions, pH value ~7.

[0029] (6) Dry at 110°C for 12 hours.

[0030] (7) Calcinate at 450°C for 5 hours to obtain the desired catalyst.

[0031] A further technical solution of the present invention is that the hydrogenation reaction is carried out in a continuous gas phase fixed bed reactor.

[0032] A further technical solution of the present invention is that the hydrogenation reaction is carried out in a continuous fixed bed reactor, and the fixed bed reactor is a tube-in-tube fixed bed reactor.

[0033] A method for producing delta-valerolactone by catalytic dehydrogenation of 1,5-pentanediol, characterized in that 1,5-pentanediol is dehydrogenated and cyclized to produce delta-valerolactone under the catalytic action of a copper-based catalyst on a composite carrier;

[0034] The catalyst is a dehydrogenation-cyclization functional catalyst, the composition of the dehydrogenation-cyclization functional catalyst is CuO / ZnO-Al2O3-La2O3, the active component is CuO, the composite oxide carrier is ZnO-Al2O3-La2O3, the H2 pressure in the dehydrogenation conversion process is 0.05MPa, and the temperature is 230-240°C.

[0035] The method for producing delta-valerolactone by catalytic dehydrogenation of 1,5-pentanediol is characterized in that:

[0036] The dehydrogenation-cyclization catalyst needs to be reduced and activated before use, and the activation steps are: first, 1-15% hydrogen is introduced, and the other components are inert gases, and the temperature is gradually increased from room temperature to 150°C for 10 hours, and the temperature is kept constant for 2 hours; then, the temperature is slowly increased to 250°C for 10 hours and the temperature is kept constant for 5 hours; this process is at normal pressure, and then it is gradually switched to pure hydrogen, and the reduction is completed.

[0037] A further technical solution of the present invention is that the reaction conditions of the dehydrogenation process are:

[0038] The H2 pressure is 0.05MPa, the temperature is 230-240°C, the liquid hourly space velocity is ~0.1h-1, and the molar ratio of hydrogen to 1,5-pentanediol is 10-20.

[0039] The present invention adopting the above technical solution has the following beneficial effects compared with the prior art: Due to the use of a composite carrier copper-based catalyst, the present invention can achieve directional catalytic conversion of 1,5-pentanediol under the conditions of H2 pressure of 0.05MPa and temperature of 230-240°C. The method can be used in reactors such as continuous gas phase fixed bed to achieve efficient catalytic conversion of 1,5-pentanediol. The catalyst has stable properties, simple separation process, and is valuable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to further illustrate the present invention, the following is further described in conjunction with the accompanying drawings:

[0041] Figure 1 It is a synthetic route for dehydrogenation of 1,5-pentanediol to δ-valerolactone;

[0042] Figure 2 Table 1 shows the effects of different catalysts on the dehydrogenation of 1,5-pentanediol to produce δ-valerolactone;

[0043] Figure 3 Table 2 shows the effect of reaction temperature on 1,5-pentanediol conversion and δ-valerolactone selectivity. DETAILED DESCRIPTION

[0044] The present invention will be further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0045] The embodiment of the present invention provides a method for producing δ-valerolactone, which comprises selectively dehydrogenating and cyclizing 1,5-pentanediol under the catalytic action of a composite carrier co-precipitated copper-based catalyst to generate δ-valerolactone.

[0046] In the above method, pure 1,5-pentanediol without adding solvent is used;

[0047] The method adopts a continuous gas phase fixed bed reactor to prepare delta-valerolactone.

[0048] The above method adopts a fixed bed reaction to prepare 1,5-pentanediol, specifically: first, the copper catalyst on the composite carrier is reduced with a hydrogen-nitrogen mixed gas at 250° C. for 5 hours, and then pure 1,5-pentanediol is used to react to generate δ-valerolactone under the conditions of a reaction temperature of 220 to 250° C., 0.05 MPa, a space velocity of 0.1, and a hydrogen-alcohol molar ratio of 15.

[0049] Example 1

[0050] First, prepare 1 mol / L copper nitrate, zinc nitrate and aluminum nitrate solutions, stir and mix them evenly to obtain a mixed metal salt acid solution. Then prepare a mixed alkali with a sodium hydroxide / sodium carbonate molar ratio of about 6, and a solution of about 1 mol / L as a precipitant. Under strong stirring conditions, the above acid solution and alkali solution are added dropwise to the precipitation kettle in parallel to perform co-precipitation, and the precipitation temperature is controlled at 40-45°C and the pH value is 10; the temperature is raised to 80°C for aging for 20 hours, then filtered, washed, dried at 110°C for 12 hours, and calcined at 450°C for about 5 hours to obtain a CuO / ZnO-Al2O3 catalyst. Based on the total amount of catalyst: the content of CuO is 22%, the content of ZnO is 60%, and the content of Al2O3 is 18%. The catalyst is marked as Cat1 and the reaction results are shown in Table 1.

[0051] Example 2

[0052] First, prepare 1 mol / L copper nitrate, zinc nitrate and aluminum nitrate solutions, stir and mix them evenly to obtain a mixed metal salt acid solution. Then prepare a mixed alkali with a sodium hydroxide / sodium carbonate molar ratio of about 6, and a solution of about 1 mol / L as a precipitant. Under strong stirring conditions, the above acid solution and alkali solution are added dropwise to the precipitation kettle in parallel to perform co-precipitation, and the precipitation temperature is controlled at 40-45°C and the pH value is 10; the temperature is raised to 80°C for aging for 20 hours, then filtered, washed, dried at 110°C for 12 hours, and calcined at 450°C for about 5 hours to obtain a CuO / ZnO-Al2O3 catalyst. Based on the total amount of catalyst: the content of CuO is 25%, the content of ZnO is 54%, and the content of Al2O3 is 21%. The catalyst is marked as Cat2. The reaction results are shown in Table 1.

[0053] Example 3

[0054] (1) First, prepare 1 mol / L copper nitrate, zinc nitrate and aluminum nitrate solutions, stir and mix them evenly to obtain a mixed metal salt acid solution. Then prepare a mixed alkali solution with a molar ratio of sodium hydroxide to sodium carbonate of about 6, and a solution of about 1 mol / L as a precipitant. Under strong stirring conditions, the above acid solution and alkali solution are added dropwise to the precipitation kettle in parallel to perform co-precipitation, and the precipitation temperature is controlled at 40-45°C and the pH value is 10; the temperature is raised to 80°C for aging for 20 hours, and then filtered, washed, dried at 110°C for 12 hours, and calcined at 450°C for about 5 hours to obtain a CuO / ZnO-Al2O3 catalyst. Based on the total amount of the catalyst: the content of CuO is 27%, the content of ZnO is 50%, and the content of Al2O3 is 23%. The catalyst is marked as Cat3. The reaction results are shown in Table 1.

[0055] Example 4

[0056] (1) First, prepare 1 mol / L copper nitrate, zinc nitrate, aluminum nitrate, and lanthanum nitrate solutions, stir and mix them evenly to obtain a mixed metal salt acid solution. Then prepare a mixed alkali solution with a molar ratio of sodium hydroxide to sodium carbonate of about 6, and a solution of about 1 mol / L as a precipitant. Under strong stirring conditions, the above acid solution and alkali solution are added dropwise to the precipitation kettle in parallel to perform co-precipitation, and the precipitation temperature is controlled at 40-45°C and the pH value is 10; the temperature is raised to 80°C for aging for 20 hours, and then filtered, washed, dried at 110°C for 12 hours, and calcined at 450°C for about 5 hours to obtain CuO / ZnO-Al2O3-La2O3. Based on the total amount of catalyst: the content of CuO is 25%, the content of ZnO is 50%, the content of Al2O3 is 22%, and the content of La2O3 is 3%. The catalyst is marked as Cat4. The reaction results are shown in Table 1.

[0057] Example 5

[0058] (1) First, prepare 1 mol / L copper nitrate, zinc nitrate, aluminum nitrate, and lanthanum nitrate solutions, stir and mix them evenly to obtain a mixed metal salt acid solution. Then prepare a mixed alkali solution with a molar ratio of sodium hydroxide to sodium carbonate of about 6, and a solution of about 1 mol / L as a precipitant. Under strong stirring conditions, the above acid solution and alkali solution are added dropwise to the precipitation kettle in parallel to perform co-precipitation, and the precipitation temperature is controlled at 40-45°C and the pH value is 10; the temperature is raised to 80°C for aging for 20 hours, and then filtered, washed, dried at 110°C for 12 hours, and calcined at 450°C for about 5 hours to obtain CuO / ZnO-Al2O3-La2O3. Based on the total amount of catalyst: the content of CuO is 25%, the content of ZnO is 52%, the content of Al2O3 is 17%, and the content of La2O3 is 6%. The catalyst is marked as Cat5. The reaction results are shown in Table 1.

[0059] Reaction conditions: 50g of catalyst was loaded into a fixed bed reactor, and first reduced at 250°C with hydrogen for 5 hours; reaction pressure 0.05MPa, reaction temperature 240°C, space velocity 0.1, hydrogen / 1,5-pentanediol molar ratio 15 under solvent-free conditions. The conversion rate of 1,5-pentanediol and the selectivity of δ-valerolactone are shown in Table 1, and other major by-products are n-pentanol and tetrahydropyran.

[0060] Example 1 Product distribution: n-pentanol 2.1%, tetrahydropyran 2.7%, delta-valerolactone 95.2%.

[0061] Product distribution of Example 4: n-pentanol 0.8%, tetrahydropyran 1.1%, δ-valerolactone 98.1%.

[0062] Table 1. Effects of different catalysts on the dehydrogenation of 1,5-pentanediol to δ-valerolactone

[0063]

[0064] Example 6

[0065] From the results of the dehydrogenation of 1,5-pentanediol to generate δ-valerolactone with different catalysts in Table 1, it can be concluded that the catalyst of Example 4 obtains the best δ-valerolactone yield. Therefore, 50 g of the catalyst of Example 4 was reloaded into the fixed bed reactor, and first reduced at 250° C. and hydrogen for 5 hours; then, under the conditions of a space velocity of 0.1 and a hydrogen / 1,5-pentanediol molar ratio of 15 without solvent, the effects of reaction temperature on the conversion of 1,5-pentanediol and the selectivity of δ-valerolactone were investigated, as shown in Table 2.

[0066] Table 2. Effect of reaction temperature on 1,5-pentanediol conversion and δ-valerolactone selectivity

[0067]

[0068] From the results of the effect of reaction temperature on 1,5-pentanediol conversion and δ-valerolactone selectivity in Table 2, it can be concluded that when the reaction pressure is 0.05 MPa, the 1,5-pentanediol space velocity is 0.1, and the hydrogen / 1,5-pentanediol molar ratio is 15, the reaction temperature is in the range of 230-240°C, the 1,5-pentanediol conversion and δ-valerolactone selectivity are the highest.

[0069] From the above data, it can be seen that on the CuO / ZnO-Al2O3-La2O3 dehydrogenation catalyst, the composition of 25%CuO / 50%ZnO-22%Al2O3-3%La2O3 catalyst can achieve high selectivity for preparing δ-valerolactone from 1,5-pentanediol with a yield of about 98%.

[0070] In summary, the present invention uses a composite carrier copper-based catalyst to achieve directional catalytic conversion of 1,5-pentanediol under the conditions of H2 pressure of 0.05MPa and temperature of 230-240°C. The method can be used in reactors such as continuous gas phase fixed bed to achieve efficient catalytic conversion of 1,5-pentanediol. The catalyst has stable properties, simple separation process, and is valuable for industrial production.

[0071] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

[0072] In general, the present invention is to produce δ-valerolactone by catalytic dehydrogenation cyclization of 1,5-pentanediol under the catalytic action of a copper-based catalyst on a composite carrier. 1,5-pentanediol is used as a raw material and converted into δ-valerolactone by dehydrogenation on a copper-based catalyst, with tetrahydropyran, n-pentanol, etc. as by-products. The dehydrogenation-cyclization catalyst composition is CuO / ZnO-Al2O3-La2O3, the hydrogenation component is CuO, the composite oxide carrier is ZnO-Al2O3-La2O3, and the pressure conditions of the dehydrogenation conversion process are: H2 pressure is 0.05MPa, and the temperature is 230-240°C.

[0073] The basic principle, main features and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the protection required.

Claims

1. A catalyst for the method of producing delta-valerolactone by catalytic dehydrogenation of 1,5-pentanediol, characterized in that: The catalyst is a dehydrogenation-cyclization functional catalyst, the composition of the dehydrogenation-cyclization functional catalyst is CuO / ZnO-Al2O3-La2O3, the active component is CuO, and the composite oxide carrier is ZnO-Al2O3-La2O3.

2. The catalyst for the method for producing delta-valerolactone by catalytic dehydrogenation of 1,5-pentanediol as claimed in claim 1, characterized in that: The dehydrogenation-cyclization functional catalyst has the following components in parts by weight: CuO is 20-35 parts, ZnO is 45-60 parts, Al2O3 is 15-23 parts, and La2O3 is 2-7 parts, and the above units are parts by weight.

3. The catalyst for the method for producing delta-valerolactone by catalytic dehydrogenation of 1,5-pentanediol as claimed in claim 2, characterized in that: The content of each component is: CuO content is 22-27%, ZnO content is 50-54%, Al2O3 content is 18-22%, and La2O3 content is 3-5%.

4. A method for preparing a catalyst for the method of producing delta-valerolactone by catalytic dehydrogenation of 1,5-pentanediol, characterized in that: The method is prepared by co-current co-precipitation, wherein the metal salt solutions of the active components are first prepared in the required proportions; Then prepare a precipitant: a mixed alkaline solution with a molar ratio of sodium hydroxide to sodium carbonate of 6; Then, at the temperature and pH value, the metal salt solution and the mixed alkaline solution of sodium hydroxide / sodium carbonate are added dropwise to the precipitation kettle in parallel, stirred for 1 hour, heated to 80°C and aged for 20 hours, filtered, washed, dried and calcined to obtain the desired dehydrogenation catalyst.

5. The method for preparing the catalyst for the method for producing delta-valerolactone by catalytic dehydrogenation of 1,5-pentanediol as claimed in claim 4, characterized in that: The specific catalyst preparation includes the following steps: (1) preparing 1 mol / L copper nitrate, zinc nitrate, aluminum nitrate, and lanthanum nitrate solutions, stirring and dissolving them, and mixing them uniformly to obtain a uniformly mixed acidic salt solution; (2) preparing a mixed alkali solution with a molar ratio of sodium hydroxide to sodium carbonate of 6:1 and a 1 mol / L solution as a precipitant; (3) adding the acid solution and alkali solution prepared in (1) and (2) above to the precipitation kettle in parallel and dropping them to perform co-precipitation, stirring vigorously, and controlling the precipitation temperature to 40-45° C. and the pH value to 10; (4) Continue stirring, raise the temperature to 80°C, and age for 20 hours; (5) Filter and wash to remove residual sodium ions, pH value ~7; (6) Dry at 110°C for 12 hours; (7) Calcinate at 450°C for 5 hours to obtain the desired catalyst.

6. The method for preparing the catalyst for the method for producing delta-valerolactone by catalytic dehydrogenation of 1,5-pentanediol as claimed in claim 4, characterized in that: The hydrogenation reaction is carried out in a continuous gas phase fixed bed reactor.

7. The method for preparing the catalyst for the method for producing delta-valerolactone by catalytic dehydrogenation of 1,5-pentanediol as claimed in claim 6, characterized in that: The hydrogenation reaction is carried out in a continuous fixed bed reactor, and the fixed bed reactor is a tube-in-tube fixed bed reactor.

8. A method for producing delta-valerolactone by catalytic dehydrogenation of 1,5-pentanediol, characterized in that: Under the catalytic action of the copper-based catalyst on the composite support, 1,5-pentanediol is dehydrogenated and cyclized to produce δ-valerolactone; The catalyst is a dehydrogenation-cyclization functional catalyst, the composition of the dehydrogenation-cyclization functional catalyst is CuO / ZnO-Al2O3-La2O3, the active component is CuO, the composite oxide carrier is ZnO-Al2O3-La2O3, the H2 pressure in the dehydrogenation conversion process is 0.05MPa, and the temperature is 230-240°C.

9. A method for producing delta-valerolactone by catalytic dehydrogenation of 1,5-pentanediol, characterized in that: The dehydrogenation-cyclization catalyst needs to be reduced and activated before use, and the activation steps are: first, 1-15% hydrogen is introduced, and the other components are inert gases, and the temperature is gradually increased from room temperature to 150°C for 10 hours, and the temperature is kept constant for 2 hours; then, the temperature is slowly increased to 250°C for 10 hours and the temperature is kept constant for 5 hours; this process is at normal pressure, and then it is gradually switched to pure hydrogen, and the reduction is completed.

10. The method for producing delta-valerolactone by catalytic dehydrogenation of 1,5-pentanediol as claimed in claim 9, characterized in that: The reaction conditions of the dehydrogenation process are: H2 pressure of 0.05MPa, temperature of 230-240°C, liquid hourly space velocity of ~0.1h-1, and molar ratio of hydrogen to 1,5-pentanediol of 10-20.

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