Catalyst and preparation method thereof, and preparation method of menthanediol

Abstract

The present invention discloses a catalyst and a preparation method thereof, and a preparation method of a diol. A catalyst comprises a metal oxide and a carrier, wherein the metal oxide comprises at least one of tungsten metal oxide, cerium metal oxide, zirconium metal oxide, and molybdenum metal oxide. A preparation method of the above catalyst comprises: 1) impregnating the carrier with a metal salt solution to obtain a mixture, wherein the metal salt solution comprises at least one of tungsten metal salt solution, cerium metal salt solution, zirconium metal salt solution, and molybdenum metal salt solution; 2) stirring the mixture and drying it to obtain a catalyst. A preparation method of a diol comprises: 1) mixing citronellal, a solvent, and the above catalyst to obtain a mixture; 2) stirring the mixture to react, filtering after the reaction, and obtaining a filtrate containing the diol. The catalyst provided by the present invention catalyzes the diol and has the characteristics of high conversion rate and high selectivity.

Description

Technical Field

[0001] The invention relates to the field of mosquito repellents, and in particular to a catalyst and a preparation method thereof, and a preparation method of menthyl glycol. Background Art

[0002] In recent years, mosquito-borne infectious diseases have received increasing attention. Good personal protection is one of the important measures to prevent mosquito-borne infectious diseases. Applying mosquito repellent is the simplest and most effective way to prevent mosquito bites. Repellents are mainly divided into two categories according to their ingredients: chemical synthesis and plant-derived. Currently, the chemical synthetic repellents sold on the market are mostly DEET, hydroxybenzoate, etc.

[0003] However, chemical synthetic repellents have significant toxic side effects, and people have questioned the selection of such repellents. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention provides a catalyst and a preparation method thereof, and a preparation method of menthyl glycol, aiming to solve the problem that chemically synthesized repellents have significant toxic side effects.

[0005] To achieve the above object, the present invention provides a catalyst, comprising a metal oxide and a carrier, wherein the metal oxide comprises at least one of tungsten metal oxide, cerium metal oxide, zirconium metal oxide, and molybdenum metal oxide.

[0006] Optionally, the loading amount of the metal oxide is 1% to 30%.

[0007] Optionally, the carrier includes at least one of a zeolite molecular sieve carrier, an oxide carrier, and a carbon-based material carrier.

[0008] Optionally, the type of the zeolite molecular sieve carrier includes: at least one of HZSM-5, ZSM-5, Hβ, HY, USY, and MFI; and / or, the oxide carrier includes SiO 2 、Al 2 O 3 、ZnO、MgO、TiO 2 At least one of; and / or, the carbon-based material carrier includes at least one of activated carbon, carbon nanotubes, graphene, silicon carbide, and Co-NC.

[0009] Optionally, the catalyst is used in a reaction of preparing menthanediol from citronellal.

[0010] In order to achieve the above-mentioned purpose, the present invention also proposes a method for preparing the above-mentioned catalyst, comprising the following steps: 1) impregnating a carrier with a metal salt solution to obtain a mixture, wherein the metal salt solution includes at least one of a tungsten metal salt solution, a cerium metal salt solution, a zirconium metal salt solution, and a molybdenum metal salt solution; 2) stirring the mixture and then drying it to obtain a catalyst.

[0011] Optionally, in step 1), the mass ratio of the metal salt solution to the carrier is (0.015-1.136):1; and / or the stirring temperature is 0-100°C.

[0012] In order to achieve the above object, the present invention also proposes a method for preparing menthyl glycol, comprising the following steps: 1) mixing citronellal, a solvent, and a catalyst as described in any one of claims 1 to 5 to obtain a mixture; 2) stirring the mixture to react, filtering after the reaction, and obtaining a filtrate containing the menthyl glycol.

[0013] Optionally, the reaction temperature is 0-100° C.; and / or the reaction time is 1-24 hours.

[0014] Optionally, the solvent is at least one of water, dodecane, methanol, ethanol, propanol, n-hexane and n-hexanol.

[0015] Beneficial effects of the present invention: The catalyst provided by the present invention is a multiphase catalyst in which a metal oxide is supported on a carrier, and in a mixed solvent system consisting of water, an organic solvent or water and an organic solvent, a high conversion rate and high selectivity can be achieved in the reaction of preparing menthyl glycol from citronellal. At the same time, the catalyst has high hydrothermal stability and high stable recycling performance, so that the preparation process of menthyl glycol is simple, the reaction equipment is simple, the reaction conditions are mild, the reactants are cheap and easy to obtain, and it is suitable for industrial production and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] 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 related drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 This is a transmission electron microscope (TEM) image of the catalyst prepared in Example 1 of the present invention.

[0018] Figure 2 X-ray diffraction (XRD) patterns of the catalysts prepared in Examples 1 and 24 of the present invention.

[0019] Figure 3 This is a temperature programmed desorption (TPD) spectrum of the catalyst in Example 15 of the present invention.

[0020] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be clearly and completely described below. It should be understood that the following examples are only used to explain the present invention and are not intended to limit the present invention. If specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0022] Unless defined otherwise, all technical and scientific terms used herein have the common meaning in the art to which the claimed subject matter belongs.

[0023] In order to facilitate understanding of this embodiment, the symbolic terms are explained as follows:

[0024] In catalytic chemistry, the loading amount is used to express the mass ratio of the active component in the supported catalyst to the mass ratio of the support plus the active component, which can be directly calculated or quantitatively characterized by XRD. In this example, the former is used for calculation.

[0025] HZSM-5, ZSM-5, Hβ, HY, USY, and MFI are models of zeolite molecular sieve carriers, and are chemical terms announced by the National Committee for the Examination of Scientific and Technological Terms.

[0026] Co-NC is a carbon-based material support co-doped with nitrogen and transition metals.

[0027] TEM stands for Transmission electron microscope, which can see sub-microscopic structures and is often used for catalyst characterization.

[0028] XRD stands for X-ray diffraction. XRD is a research method that analyzes the diffraction pattern to obtain information such as the composition of the material, the structure or morphology of the atoms or molecules inside the material. It is used to determine the crystal structure and is often used for catalyst characterization.

[0029] TPD stands for Temperature Programmed Desorption, which refers to programmed temperature desorption. It is the process of removing the chemically adsorbed part of the catalyst that has been pre-adsorbed with active components. It is often used in catalyst characterization.

[0030] At present, mosquito repellents are mainly divided into two categories according to their ingredients: chemical synthesis and plant-derived. The chemical synthesis repellents currently sold on the market are mostly DEET, hydroxybenzoate, etc.

[0031] However, chemical synthetic repellents have significant toxic side effects, and people have questioned the selection of such repellents.

[0032] In order to solve the above problems, the present invention proposes a catalyst, comprising a metal oxide and a carrier, wherein the metal oxide comprises at least one of tungsten metal oxide, cerium metal oxide, zirconium metal oxide, and molybdenum metal oxide.

[0033] Preferably, the metal oxide loading is 1%-30%, so that the reactants can undergo hydration reaction and the target product can be prepared with high conversion rate and high selectivity.

[0034] Preferably, the molecular sieve carrier in this embodiment includes at least one of a zeolite molecular sieve carrier, an oxide carrier, and a carbon-based material carrier.

[0035] Preferably, the type of the zeolite molecular sieve carrier includes: at least one of HZSM-5, ZSM-5, Hβ, HY, USY, and MFI; the oxide carrier includes SiO 2 、Al 2 O 3 、ZnO、MgO、TiO 2 At least one of; the carbon-based material carrier includes at least one of activated carbon, carbon nanotubes, graphene, silicon carbide, and Co-NC. The carrier selected in this embodiment can make the prepared catalyst have a suitable shape, size and mechanical strength, and can also prevent the active components from sintering during use, thereby improving the heat resistance of the catalyst. If the molecular sieve is used as the carrier, the active components can reach a dispersion close to the atomic level.

[0036] Preferably, the catalyst is used in the reaction of preparing menthyl glycol from citronellal. In this embodiment, the catalyst catalyzes the hydration reaction of citronellal to prepare menthyl glycol in a mixed solvent system consisting of water, an organic solvent or water and an organic solvent.

[0037] In order to solve the above problems, the present invention also provides a method for preparing a catalyst, comprising the following steps:

[0038] 1) impregnating a carrier with a metal salt solution to obtain a mixture, wherein the metal salt solution comprises at least one of a tungsten metal salt solution, a cerium metal salt solution, a zirconium metal salt solution, and a molybdenum metal salt solution;

[0039] Specifically, 50-150 mL of an aqueous solution of 0.015-1.136 g of a metal salt is used to impregnate 1.0 g of the support.

[0040] 2) The mixture is stirred and then dried to obtain a catalyst.

[0041] Specifically, after stirring at 0-100° C. for 12-24 h, the system is placed in a rotary evaporator to remove the dispersant by rotary evaporation, and then dried at 20-100° C. for 6-12 h to obtain the catalyst.

[0042] Preferably, the mass ratio of the metal salt to the carrier is (0.015-1.136): 1, and the preset temperature is 0-100°C. The selection of the mass ratio of the metal salt to the molecular sieve carrier and the reaction temperature in this embodiment is based on the fact that the provided ratio and temperature can allow the active component metal salt to penetrate into the pores of the molecular sieve carrier with relatively more active phases entering, increasing the loading amount and directly improving the catalytic performance of the catalyst. It is worth noting that the temperature is more preferably 0-80°C.

[0043] In order to solve the above problems, the present invention also provides a method for preparing menthyl glycol, comprising the following steps:

[0044] 1) adding citronellal, a solvent and the above catalyst into a reaction vessel to obtain a mixture;

[0045] Specifically, 500 mg of citronellal, a heterogeneous catalyst with different loading amounts of metals supported on a molecular sieve carrier, and a solvent were added into a 15 mL pressure tube to obtain a mixture.

[0046] 2) stirring the mixture to react, and filtering after the reaction is completed for a preset time to obtain a filtrate containing the menthanediol.

[0047] Specifically, the pressure tube is heated to 25° C., reacted for 15 hours under stirring conditions, cooled to room temperature, vented, filtered, and the catalyst is separated from the reaction solution to obtain a solid phase catalyst and a filtrate containing the menthanediol.

[0048] Preferably, the reaction temperature is 0-100° C., and the reaction time is 1-24 hours.

[0049] Preferably, the solvent is at least one of water, dodecane, methanol, ethanol, propanol, n-hexane and n-hexanol.

[0050] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments.

[0051] Embodiment 1:

[0052] Preparation of 5% tungsten metal loading catalyst: Weigh 0.075g of ammonium metatungstate in a beaker, add 50mL of water to dissolve, obtain an aqueous solution of ammonium metatungstate, and impregnate 1.0g of HZSM-5 carrier with the aqueous solution of ammonium metatungstate. After stirring at 50°C for 12 hours, put the system into a rotary evaporator, remove water by rotary evaporation, and then dry at 100°C for 6 hours to obtain the catalyst.

[0053] Preparation of menthyl glycol: 500 mg of citronellal, 5% tungsten metal loaded catalyst, and 5 mL of water were added to a 15 mL pressure tube to obtain a mixture. The pressure tube was heated to 50°C, reacted for 12 hours under stirring conditions, cooled to room temperature, vented, filtered, and the catalyst was separated from the reaction solution to obtain a solid phase catalyst after the reaction and a filtrate containing the menthyl glycol.

[0054] Embodiment 2:

[0055] Preparation of 20% cerium metal loading catalyst: Weigh 0.75 g of ceric acid hexanitrate in a beaker, add 150 mL of water to dissolve, obtain an aqueous solution of ceric acid hexanitrate, and impregnate 1.0 g of ZSM-5 carrier with the aqueous solution of ceric acid hexanitrate. After stirring at 50°C for 12 hours, put the system into a rotary evaporator, remove water by rotary evaporation, and then dry at 100°C for 6 hours to obtain the catalyst.

[0056] Preparation of menthyl glycol: 500 mg of citronellal, 20% cerium metal loaded catalyst, and 5 mL of water were added to a 15 mL pressure tube to obtain a mixture. The pressure tube was heated to 50°C, reacted for 12 hours under stirring conditions, cooled to room temperature, vented, filtered, and the catalyst was separated from the reaction liquid to obtain a solid phase catalyst after the reaction and a filtrate containing the menthyl glycol.

[0057] Embodiment 3:

[0058] Preparation of 20% zirconium metal loading catalyst: Weigh 0.75 g of ammonium metazirconate into a beaker, add 150 mL of water to dissolve, obtain an aqueous solution of ammonium metazirconate, and impregnate 1.0 g of Hβ carrier with the aqueous solution of ammonium metazirconate. After stirring at 50°C for 12 hours, put the system into a rotary evaporator, remove water by rotary evaporation, and then dry at 100°C for 6 hours to obtain the catalyst.

[0059] Preparation of menthyl glycol: 500 mg of citronellal, 20% zirconium metal loading catalyst, and 5 mL of water were added to a 15 mL pressure tube to obtain a mixture. The pressure tube was heated to 50°C, reacted for 12 hours under stirring conditions, cooled to room temperature, vented, filtered, and the catalyst was separated from the reaction solution to obtain a solid phase catalyst after the reaction and a filtrate containing the menthyl glycol.

[0060] Embodiment 4:

[0061] Preparation of 15% tungsten metal loading catalyst: Weigh 0.225g of ammonium metatungstate in a beaker, add 100mL of water to dissolve, obtain an aqueous solution of ammonium metatungstate, and impregnate 1.0g of MFI carrier with the aqueous solution of ammonium metatungstate. After stirring at 50°C for 12 hours, put the system into a rotary evaporator, remove water by rotary evaporation, and then dry at 100°C for 6 hours to obtain the catalyst.

[0062] Preparation of menthyl glycol: 500 mg of citronellal, 5% tungsten metal loaded catalyst, and 5 mL of water were added to a 15 mL pressure tube to obtain a mixture. The pressure tube was heated to 50°C, reacted for 12 hours under stirring conditions, cooled to room temperature, vented, filtered, and the catalyst was separated from the reaction solution to obtain a solid phase catalyst after the reaction and a filtrate containing the menthyl glycol.

[0063] Embodiment 5:

[0064] Preparation of 30% molybdenum metal loading catalyst: weigh 1.136 g of ammonium metamolybdate into a beaker, add 150 mL of water to dissolve, and obtain an aqueous solution of ammonium metamolybdate. Use the aqueous solution of ammonium metamolybdate to impregnate 1.0 g of TiO 2 After stirring at 50° C. for 12 hours, the system was placed in a rotary evaporator to remove water by rotary evaporation, and then dried at 100° C. for 6 hours to obtain the catalyst.

[0065] Preparation of menthyl glycol: 500 mg of citronellal, 30% molybdenum metal loading catalyst, and 5 mL of water were added to a 15 mL pressure tube to obtain a mixture. The pressure tube was heated to 50°C, reacted for 12 hours under stirring conditions, cooled to room temperature, vented, filtered, and the catalyst was separated from the reaction solution to obtain a solid phase catalyst after the reaction and a filtrate containing the menthyl glycol.

[0066] Embodiment 6:

[0067] Preparation of 20% tungsten metal loading catalyst: weigh 0.3 g of ammonium metatungstate in a beaker, add 100 mL of water to dissolve, and obtain an aqueous solution of ammonium metatungstate. Use the aqueous solution of ammonium metatungstate to impregnate 1.0 g of Al 2 O 3 After stirring at 50° C. for 12 hours, the system was placed in a rotary evaporator to remove water by rotary evaporation, and then dried at 100° C. for 6 hours to obtain the catalyst.

[0068] Preparation of menthyl glycol: 500 mg of citronellal, 20% tungsten metal loaded catalyst, and 5 mL of water were added to a 15 mL pressure tube to obtain a mixture. The pressure tube was heated to 50° C. and reacted for 12 hours under stirring conditions. After cooling to room temperature, the mixture was vented and filtered to separate the catalyst from the reaction solution to obtain a solid phase catalyst after the reaction and a filtrate containing the menthyl glycol.

[0069] Embodiment 7:

[0070] Preparation of 10% cerium metal loading catalyst: 0.375 g of hexanitrate ceric acid was weighed into a beaker, and 150 mL of water was added to dissolve it to obtain an aqueous solution of hexanitrate ceric acid, and 1.0 g of AC carrier was impregnated with the aqueous solution of hexanitrate ceric acid. After stirring at 50°C for 12 hours, the system was placed in a rotary evaporator to remove water by rotary evaporation, and then dried at 100°C for 6 hours to obtain the catalyst.

[0071] Preparation of menthyl glycol: 500 mg of citronellal, 10% cerium metal loaded catalyst, and 5 mL of water were added to a 15 mL pressure tube to obtain a mixture. The pressure tube was heated to 50°C, reacted for 12 hours under stirring conditions, cooled to room temperature, vented, filtered, and the catalyst was separated from the reaction solution to obtain a solid phase catalyst after the reaction and a filtrate containing the menthyl glycol.

[0072] Embodiment 8:

[0073] Preparation of 10% zirconium metal loading catalyst: Weigh 0.375g of ammonium metazirconate into a beaker, add 100mL of water to dissolve, obtain an aqueous solution of ammonium metazirconate, and impregnate 1.0g of CNT carrier with the aqueous solution of ammonium metazirconate. After stirring at 50°C for 12 hours, put the system into a rotary evaporator, remove water by rotary evaporation, and then dry at 100°C for 6 hours to obtain the catalyst.

[0074] Preparation of menthyl glycol: 500 mg of citronellal, 10% zirconium metal loading catalyst, and 5 mL of water were added to a 15 mL pressure tube to obtain a mixture. The pressure tube was heated to 50°C, reacted for 12 hours under stirring conditions, cooled to room temperature, vented, filtered, and the catalyst was separated from the reaction solution to obtain a solid phase catalyst after the reaction and a filtrate containing the menthyl glycol.

[0075] Embodiment 9:

[0076] Preparation of 8% tungsten metal loading catalyst: Weigh 0.12g of ammonium metatungstate into a beaker, add 100mL of water to dissolve, obtain an aqueous solution of ammonium metatungstate, and impregnate 1.0g of NC carrier with the aqueous solution of ammonium metatungstate. After stirring at 50°C for 12 hours, put the system into a rotary evaporator, remove water by rotary evaporation, and then dry at 100°C for 6 hours to obtain the catalyst.

[0077] Preparation of menthyl glycol: 500 mg of citronellal, 8% tungsten metal loaded catalyst, and 5 mL of water were added to a 15 mL pressure tube to obtain a mixture. The pressure tube was heated to 50° C., reacted for 12 hours under stirring conditions, cooled to room temperature, vented, filtered, and the catalyst was separated from the reaction liquid to obtain a solid phase catalyst after the reaction and a filtrate containing the menthyl glycol.

[0078] Embodiment 10:

[0079] Preparation of 10% tungsten metal loading catalyst: Weigh 0.15g of ammonium metatungstate in a beaker, add 100mL of water to dissolve, obtain an aqueous solution of ammonium metatungstate, and impregnate 1.0g of MFI carrier with the aqueous solution of ammonium metatungstate. After stirring at 50°C for 12 hours, put the system into a rotary evaporator, remove water by rotary evaporation, and then dry at 100°C for 6 hours to obtain the catalyst.

[0080] Preparation of menthyl glycol: 500 mg of citronellal, 10% tungsten metal loaded catalyst, and 5 mL of water were added to a 15 mL pressure tube to obtain a mixture. The pressure tube was heated to 100° C. and reacted for 5 hours under stirring conditions. After cooling to room temperature, the mixture was vented and filtered to separate the catalyst from the reaction solution to obtain a solid phase catalyst after the reaction and a filtrate containing the menthyl glycol.

[0081] Embodiment 11:

[0082] Preparation of 1% tungsten metal loading catalyst: Weigh 0.015g of ammonium metatungstate in a beaker, add 50mL of water to dissolve, obtain an aqueous solution of ammonium metatungstate, and impregnate 1.0g of HZSM-5 carrier with the aqueous solution of ammonium metatungstate. After stirring at 25°C for 12 hours, put the system into a rotary evaporator, remove water by rotary evaporation, and then dry at 100°C for 6 hours to obtain the catalyst.

[0083] Preparation of menthyl glycol: 500 mg of citronellal, 1% tungsten metal-loaded catalyst, and dodecane were added to a 15 mL pressure tube to obtain a mixture. The pressure tube was heated to 25°C, reacted for 15 hours under stirring conditions, cooled to room temperature, vented, filtered, and the catalyst was separated from the reaction solution to obtain a solid phase catalyst after the reaction and a filtrate containing the menthyl glycol.

[0084] Embodiment 12:

[0085] Preparation of 10% cerium metal loading catalyst: 0.375 g of hexanitrate ceric acid was weighed into a beaker, and 150 mL of water was added to dissolve it to obtain an aqueous solution of hexanitrate ceric acid, and 1.0 g of Hβ carrier was impregnated with the hexanitrate ceric acid aqueous solution. After stirring at 50°C for 12 hours, the system was placed in a rotary evaporator to remove water by rotary evaporation, and then dried at 100°C for 6 hours to obtain the catalyst.

[0086] Preparation of menthyl glycol: 500 mg of citronellal, 10% cerium metal loaded catalyst, and 5 mL of dodecane were added to a 15 mL pressure tube to obtain a mixture. The pressure tube was heated to 50°C, reacted for 12 hours under stirring conditions, cooled to room temperature, vented, filtered, and the catalyst was separated from the reaction solution to obtain a solid phase catalyst after the reaction and a filtrate containing the menthyl glycol.

[0087] Embodiment 13:

[0088] Preparation of 15% tungsten metal loading catalyst: Weigh 0.225g of ammonium metatungstate in a beaker, add 50mL of water to dissolve, obtain an aqueous solution of ammonium metatungstate, and impregnate 1.0g of USY carrier with the aqueous solution of ammonium metatungstate. After stirring at 25°C for 12 hours, put the system into a rotary evaporator, remove water by rotary evaporation, and then dry at 100°C for 6 hours to obtain the catalyst.

[0089] Preparation of menthyl glycol: 500 mg of citronellal, 15% tungsten metal loaded catalyst, and dodecane were added to a 15 mL pressure tube to obtain a mixture. The pressure tube was heated to 25°C, reacted for 15 hours under stirring conditions, cooled to room temperature, vented, filtered, and the catalyst was separated from the reaction solution to obtain a solid phase catalyst after the reaction and a filtrate containing the menthyl glycol.

[0090] Embodiment 14:

[0091] Preparation of 20% zirconium metal loading catalyst: Weigh 0.75g of ammonium metazirconate into a beaker, add 150mL of water to dissolve, obtain an aqueous solution of ammonium metazirconate, and impregnate 1.0g of CNT carrier with the aqueous solution of ammonium metazirconate. After stirring at 50°C for 12 hours, put the system into a rotary evaporator, remove water by rotary evaporation, and then dry at 100°C for 6 hours to obtain the catalyst.

[0092] Preparation of menthyl glycol: 500 mg of citronellal, 20% zirconium metal loading catalyst, and 5 mL of dodecane were added to a 15 mL pressure tube to obtain a mixture. The pressure tube was heated to 25° C., reacted for 15 hours under stirring conditions, cooled to room temperature, vented, filtered, and the catalyst was separated from the reaction solution to obtain a solid phase catalyst after the reaction and a filtrate containing the menthyl glycol.

[0093] Embodiment 15:

[0094] Preparation of 30% molybdenum metal loading catalyst: 1.136 g of ammonium metamolybdate was weighed into a beaker, and 150 mL of water was added to dissolve to obtain an aqueous solution of ammonium metamolybdate, and 1.0 g of HZSM-5 carrier was impregnated with the aqueous solution of ammonium metamolybdate. After stirring at 50°C for 12 hours, the system was placed in a rotary evaporator to remove water by rotary evaporation, and then dried at 100°C for 6 hours to obtain the catalyst.

[0095] Preparation of menthyl glycol: 500 mg of citronellal, 30% molybdenum metal loading catalyst, and 5 mL of dodecane were added to a 15 mL pressure tube to obtain a mixture. The pressure tube was heated to 25°C, reacted for 15 hours under stirring conditions, cooled to room temperature, vented, filtered, and the catalyst was separated from the reaction solution to obtain a solid phase catalyst after the reaction and a filtrate containing the menthyl glycol.

[0096] Embodiment 16:

[0097] Preparation of 30% tungsten metal loading catalyst: Weigh 0.45g of ammonium metatungstate into a beaker, add 100mL of water to dissolve, obtain an aqueous solution of ammonium metatungstate, and impregnate 1.0g of HZSM-5 carrier with the aqueous solution of ammonium metatungstate. After stirring at 50°C for 12 hours, put the system into a rotary evaporator, remove water by rotary evaporation, and then dry at 100°C for 6 hours to obtain the catalyst.

[0098] Preparation of menthyl glycol: 500 mg of citronellal, 30% tungsten metal loaded catalyst, and 5 mL of methanol were added to a 15 mL pressure tube to obtain a mixture. The pressure tube was cooled to 0°C, reacted for 24 hours under stirring conditions, and then cooled to room temperature, vented, filtered, and the catalyst was separated from the reaction liquid to obtain a solid phase catalyst after the reaction and a filtrate containing the menthyl glycol.

[0099] Embodiment 17:

[0100] Preparation of 5% zirconium metal loading catalyst: Weigh 0.19 g of ammonium metazirconate into a beaker, add 100 mL of water to dissolve, obtain an aqueous solution of ammonium metazirconate, and impregnate 1.0 g of NC carrier with the aqueous solution of ammonium metazirconate. After stirring at 50°C for 12 hours, put the system into a rotary evaporator to remove water by rotary evaporation, and then dry at 100°C for 6 hours to obtain the catalyst.

[0101] Preparation of menthyl glycol: 500 mg of citronellal, 5% zirconium metal loading catalyst, and 5 mL of methanol were added to a 15 mL pressure tube to obtain a mixture. The pressure tube was heated to 50° C. and reacted for 24 hours under stirring conditions. After cooling to room temperature, the mixture was vented and filtered to separate the catalyst from the reaction solution to obtain a solid phase catalyst after the reaction and a filtrate containing the menthyl glycol.

[0102] Embodiment 18:

[0103] Preparation of 10% tungsten metal loading catalyst: Weigh 0.15g of ammonium metatungstate into a beaker, add 100mL of water to dissolve, obtain an aqueous solution of ammonium metatungstate, and impregnate 1.0g of AC carrier with the aqueous solution of ammonium metatungstate. After stirring at 50°C for 12 hours, put the system into a rotary evaporator, remove water by rotary evaporation, and then dry at 100°C for 6 hours to obtain the catalyst.

[0104] Preparation of menthyl glycol: 500 mg of citronellal, 10% tungsten metal loaded catalyst, and 5 mL of methanol were added to a 15 mL pressure tube to obtain a mixture. The pressure tube was heated to 80°C, reacted for 24 hours under stirring conditions, cooled to room temperature, vented, filtered, and the catalyst was separated from the reaction liquid to obtain a solid phase catalyst after the reaction and a filtrate containing the menthyl glycol.

[0105] Embodiment 19:

[0106] Preparation of 20% cerium metal loading catalyst: weigh 0.75 g of ceric acid hexanitrate in a beaker, add 150 mL of water to dissolve, and obtain an aqueous solution of ceric acid hexanitrate. Use the aqueous solution of ceric acid hexanitrate to impregnate 1.0 g of Al 2 O 3 After stirring at 50° C. for 12 hours, the system was placed in a rotary evaporator to remove water by rotary evaporation, and then dried at 100° C. for 6 hours to obtain the catalyst.

[0107] Preparation of menthyl glycol: 500 mg of citronellal, 20% cerium metal loaded catalyst, and 5 mL of methanol were added to a 15 mL pressure tube to obtain a mixture. The pressure tube was heated to 100° C. and reacted for 24 hours under stirring conditions. After cooling to room temperature, the mixture was vented and filtered to separate the catalyst from the reaction solution to obtain a solid phase catalyst after the reaction and a filtrate containing the menthyl glycol.

[0108] Embodiment 20:

[0109] Preparation of 10% tungsten metal loading catalyst: Weigh 0.15g of ammonium metatungstate in a beaker, add 50mL of water to dissolve, obtain an aqueous solution of ammonium metatungstate, and impregnate 1.0g of ZSM-5 carrier with the aqueous solution of ammonium metatungstate. After stirring at 50°C for 12 hours, put the system into a rotary evaporator, remove water by rotary evaporation, and then dry at 100°C for 6 hours to obtain the catalyst.

[0110] Preparation of menthyl glycol: 500 mg of citronellal, 10% tungsten metal loaded catalyst, 5 mL of a mixture of water and methanol were added to a 15 mL pressure tube to obtain a mixture. The pressure tube was heated to 25°C, reacted for 1 hour under stirring conditions, cooled to room temperature, vented, filtered, and the catalyst was separated from the reaction solution to obtain a solid phase catalyst after the reaction and a filtrate containing the menthyl glycol.

[0111] Embodiment 21:

[0112] Preparation of 20% tungsten metal loading catalyst: Weigh 0.3g of ammonium metatungstate in a beaker, add 50mL of water to dissolve, obtain an aqueous solution of ammonium metatungstate, and impregnate 1.0g of MFI carrier with the aqueous solution of ammonium metatungstate. After stirring at 50°C for 12 hours, put the system into a rotary evaporator, remove water by rotary evaporation, and then dry at 100°C for 6 hours to obtain the catalyst.

[0113] Preparation of menthyl glycol: 500 mg of citronellal, 20% tungsten metal loaded catalyst, 5 mL of a mixture of water and methanol were added to a 15 mL pressure tube to obtain a mixture. The pressure tube was heated to 25°C, reacted for 6 hours under stirring conditions, cooled to room temperature, vented, filtered, and the catalyst was separated from the reaction solution to obtain a solid phase catalyst after the reaction and a filtrate containing the menthyl glycol.

[0114] Embodiment 22:

[0115] Preparation of 30% molybdenum metal loading catalyst: 1.136 g of ammonium metamolybdate was weighed into a beaker, and 150 mL of water was added to dissolve to obtain an aqueous solution of ammonium metamolybdate, and 1.0 g of HZSM-5 carrier was impregnated with the aqueous solution of ammonium metamolybdate. After stirring at 50°C for 12 hours, the system was placed in a rotary evaporator to remove water by rotary evaporation, and then dried at 100°C for 6 hours to obtain the catalyst.

[0116] Preparation of menthyl glycol: 500 mg of citronellal, 30% molybdenum metal loading catalyst, 5 mL of a mixture of water and methanol were added to a 15 mL pressure tube to obtain a mixture. The pressure tube was heated to 25° C., reacted for 10 hours under stirring conditions, cooled to room temperature, vented, filtered, and the catalyst was separated from the reaction solution to obtain a solid phase catalyst after the reaction and a filtrate containing the menthyl glycol.

[0117] Embodiment 23:

[0118] Preparation of 5% zirconium metal loading catalyst: Weigh 0.19 g of ammonium metazirconate into a beaker, add 100 mL of water to dissolve, obtain an aqueous solution of ammonium metazirconate, and impregnate 1.0 g of ZSM-5 carrier with the aqueous solution of ammonium metazirconate. After stirring at 50°C for 12 hours, put the system into a rotary evaporator, remove water by rotary evaporation, and then dry at 100°C for 6 hours to obtain the catalyst.

[0119] Preparation of menthyl glycol: 500 mg of citronellal, 5% zirconium metal loading catalyst, 5 mL of a mixture of water and methanol were added to a 15 mL pressure tube to obtain a mixture. The pressure tube was heated to 25° C., reacted for 20 hours under stirring conditions, cooled to room temperature, vented, filtered, and the catalyst was separated from the reaction solution to obtain a solid phase catalyst after the reaction and a filtrate containing the menthyl glycol.

[0120] Embodiment 24:

[0121] Preparation of 16% cerium metal loading catalyst: Weigh 0.6 g of hexanitrate ceric acid into a beaker, add 150 mL of water to dissolve, obtain an aqueous solution of hexanitrate ceric acid, and impregnate 1.0 g of ZSM-5 carrier with the hexanitrate ceric acid aqueous solution. After stirring at 50°C for 12 hours, put the system into a rotary evaporator, remove water by rotary evaporation, and then dry at 100°C for 6 hours to obtain the catalyst.

[0122] Preparation of menthyl glycol: 500 mg of citronellal, 16% cerium metal loading catalyst, 5 mL of a mixture of water and methanol were added to a 15 mL pressure tube to obtain a mixture. The pressure tube was heated to 25°C, reacted under stirring for 24 hours, cooled to room temperature, vented, filtered, and the catalyst was separated from the reaction solution to obtain a solid phase catalyst after the reaction and a filtrate containing the menthyl glycol.

[0123] Embodiment 25:

[0124] Preparation of 25% tungsten metal loading catalyst: Weigh 0.3g of ammonium metatungstate in a beaker, add 50mL of water to dissolve, obtain an aqueous solution of ammonium metatungstate, and impregnate 1.0g of HZSM-5 carrier with the aqueous solution of ammonium metatungstate. After stirring at 50°C for 12 hours, put the system into a rotary evaporator, remove water by rotary evaporation, and then dry at 100°C for 6 hours to obtain the catalyst.

[0125] Preparation of menthyl glycol: 500 mg of citronellal, 25% tungsten metal loaded catalyst, 5 mL of a mixture of water and methanol were added to a 15 mL pressure tube to obtain a mixture. The pressure tube was heated to 25°C, reacted for 5 hours under stirring conditions, cooled to room temperature, vented, filtered, and the catalyst was separated from the reaction solution to obtain a solid phase catalyst after the reaction and a filtrate containing the menthyl glycol.

[0126] Embodiment 26:

[0127] Preparation of 5% zirconium metal loading catalyst: Weigh 0.19 g of ammonium metazirconate into a beaker, add 100 mL of water to dissolve, obtain an aqueous solution of ammonium metazirconate, and impregnate 1.0 g of HZSM-5 carrier with the aqueous solution of ammonium metazirconate. After stirring at 50°C for 12 hours, put the system into a rotary evaporator, remove water by rotary evaporation, and then dry at 100°C for 6 hours to obtain the catalyst.

[0128] Preparation of menthyl glycol: 500 mg of citronellal, 5% zirconium metal loading catalyst, and 5 mL of ethanol were added to a 15 mL pressure tube to obtain a mixture. The pressure tube was heated to 100° C., reacted for 5 hours under stirring conditions, cooled to room temperature, vented, and filtered to separate the catalyst from the reaction solution, and a solid phase catalyst after the reaction and a filtrate containing the menthyl glycol were obtained.

[0129] Embodiment 27:

[0130] Preparation of 12% tungsten metal loading catalyst: Weigh 0.18g of ammonium metatungstate in a beaker, add 50mL of water to dissolve, obtain an aqueous solution of ammonium metatungstate, and impregnate 1.0g of HY carrier with the aqueous solution of ammonium metatungstate. After stirring at 50°C for 12 hours, put the system into a rotary evaporator, remove water by rotary evaporation, and then dry at 100°C for 6 hours to obtain the catalyst.

[0131] Preparation of menthyl glycol: 500 mg of citronellal, 12% tungsten metal loaded catalyst, and 5 mL of n-hexane were added to a 15 mL pressure tube to obtain a mixture. The pressure tube was heated to 100° C. and reacted for 5 hours under stirring conditions. After cooling to room temperature, the mixture was vented and filtered to separate the catalyst from the reaction solution to obtain a solid phase catalyst after the reaction and a filtrate containing the menthyl glycol.

[0132] Embodiment 28:

[0133] Preparation of 18% molybdenum metal loading catalyst: Weigh 0.682g of ammonium metamolybdate into a beaker, add 150mL of water to dissolve, obtain an aqueous solution of ammonium metamolybdate, and impregnate 1.0g of USY carrier with the aqueous solution of ammonium metamolybdate. After stirring at 50°C for 12 hours, put the system into a rotary evaporator, remove water by rotary evaporation, and then dry at 100°C for 6 hours to obtain the catalyst.

[0134] Preparation of menthyl glycol: 500 mg of citronellal, 18% molybdenum metal loading catalyst, 5 mL of a mixture of water and propanol were added to a 15 mL pressure tube to obtain a mixture. The pressure tube was heated to 100° C., reacted for 5 hours under stirring conditions, cooled to room temperature, vented, filtered, and the catalyst was separated from the reaction solution to obtain a solid phase catalyst after the reaction and a filtrate containing the menthyl glycol.

[0135] Embodiment 29:

[0136] Preparation of 30% zirconium metal loading catalyst: 0.684 g of ammonium metazirconate was weighed into a beaker, and 150 mL of water was added to dissolve to obtain an aqueous solution of ammonium metazirconate, and 1.0 g of Hβ carrier was impregnated with the aqueous solution of ammonium metazirconate. After stirring at 50°C for 12 hours, the system was placed in a rotary evaporator to remove water by rotary evaporation, and then dried at 100°C for 6 hours to obtain the catalyst.

[0137] Preparation of menthyl glycol: 500 mg of citronellal, 30% zirconium metal loading catalyst, 5 mL of water and a mixture of n-hexanol were added to a 15 mL pressure tube to obtain a mixture. The pressure tube was heated to 100° C., reacted for 5 hours under stirring conditions, cooled to room temperature, vented, filtered, and the catalyst was separated from the reaction solution to obtain a solid phase catalyst after the reaction and a filtrate containing the menthyl glycol.

[0138] Comparative Example 1:

[0139] On the basis of the optimal embodiment 9, the reaction in the pressure tube was carried out without adding a catalyst, and the obtained solution was used as comparative example 1.

[0140] Furthermore, the reaction solutions obtained in Examples 1 to 29 and Comparative Example 1 were diluted with methanol to determine the concentration and then subjected to gas chromatography analysis, thereby further describing the technical solution of the present invention in detail. The gas chromatography analysis results of the experiments are shown in Table 1.

[0141] Table 1. Catalytic performance test of catalysts

[0142]

[0143] From the reaction results in Table 1, the heterogeneous catalyst supported by metal oxide on the carrier catalyzes the hydration reaction of citronellal to prepare menthyl glycol in water, alkanes, alcohols and other organic solvents or a mixed solvent system composed of water and organic solvents. The catalytic citronellal can be converted into menthyl glycol with a high conversion rate of almost 100% and a high selectivity of more than 90%. After the metal is loaded, a large number of acid sites are added to the surface of the catalyst. As the amount of loaded metal increases, the number of acid sites will also increase. During the reaction, the conversion rate of the raw material and the selectivity of the product menthyl glycol are different due to the influence of parameters such as the type of metal oxide, the reaction solvent system, the reaction temperature and the reaction time. The results show that under the influence or control of parameters such as a carrier with strong acidity and a lower temperature (less than or equal to 50°C), the catalyst has a better selectivity to catalyze the citronellal raw material to the menthyl glycol product. It shows that the control of the reaction parameters by the heterogeneous catalyst supported by metal oxide on the carrier can achieve the preparation of menthyl glycol from citronellal under mild reaction conditions.

[0144] Therefore, the experimental results of the above embodiments show that a variety of metal oxides such as WOx, ZrOx, CeOx, and MoOx are loaded on molecular sieve carriers such as HZSM-5, ZSM-5, Hβ, HY, USY, MFI, etc., oxide carriers such as SiO2, Al2O3, ZnO, MgO, TiO2, etc., and carbon-based material carriers such as activated carbon (AC), carbon nanotubes (CNT), graphene, silicon carbide, NC, etc. The prepared supported metal heterogeneous catalyst can catalyze the hydration reaction of citronellal raw materials with a high conversion rate (100%) under relatively mild conditions (0-50 ° C, 6-15 h), and prepare menthyl glycol with high selectivity (90%), realizing a simple, green, and efficient catalyst to catalyze the conversion of citronellal under relatively mild conditions. Better method for preparing menthyl glycol with high selectivity, which can better meet the needs of industrial applications. The method of the invention has a simple process for preparing menthanediol, simple reaction equipment, easy operation, relatively mild reaction conditions, cheap and easy-to-obtain catalysts, high hydrothermal stability of the catalysts, and stable recycling performance, and is suitable for industrial production and has broad application prospects.

[0145] The above are only preferred embodiments of the present invention, and do not limit the patent scope of the present invention. For those skilled in the art, the present invention may have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the patent protection scope of the present invention.

Claims

1. A method for preparing menthanediol, characterized in that: The following steps are involved: 1) mixing citronellal, a solvent and a catalyst to obtain a mixture; 2) stirring the mixture to react, filtering after the reaction to obtain a filtrate containing the diol; wherein the reaction temperature is 0 to 100° C., and the reaction time is 1 to 24 hours; The catalyst comprises a metal oxide and a carrier, wherein the metal oxide comprises at least one of tungsten metal oxide, cerium metal oxide, zirconium metal oxide, and molybdenum metal oxide; The carrier includes at least one of a zeolite molecular sieve carrier, an oxide carrier, and a carbon-based material carrier; The type of the zeolite molecular sieve carrier includes: at least one of HZSM-5, ZSM-5, Hβ, HY, USY, and MFI; The oxide carrier includes at least one of SiO2, Al2O3, ZnO, MgO, and TiO2; The carbon-based material carrier includes at least one of activated carbon, carbon nanotubes, graphene, silicon carbide, and Co-NC; The preparation method of the catalyst is as follows: 1) impregnating the carrier with a metal salt solution to obtain a mixture, wherein the metal salt solution includes at least one of a tungsten metal salt solution, a cerium metal salt solution, a zirconium metal salt solution, and a molybdenum metal salt solution; 2) Stirring the mixture and then drying it to obtain the catalyst.

2. The method for preparing menthyl glycol according to claim 1, characterized in that: The loading amount of the metal oxide is 1% to 30%.

3. The method for preparing menthyl glycol according to claim 1, characterized in that: In step 1), the mass ratio of the metal salt solution to the carrier is (0.015-1.136):1; And / or, in step 2), the stirring temperature is 0 to 100°C.

4. The method for preparing menthyl glycol according to claim 1, characterized in that: The solvent includes at least one of water, dodecane, methanol, ethanol, propanol, n-hexane and n-hexanol.

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