Hydrogenation catalyst for citronellol preparation and preparation method and application thereof
By developing a hydrogenation catalyst including carbon support and metal, the problem of difficult treatment of the pre-distillate in the geraniol preparation process is solved, and efficient and selective preparation of citronellol is achieved, reducing production costs.
Patent Information
- Application Number
- CN202510273979.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-10
- Publication Date
- 2025-06-10
AI Technical Summary
In the prior art, the pre-distillate mixtures of citronellal, geraniol, nerolil and citronellol produced in the process of preparing geraniol are difficult to deal with, have low added value, high energy consumption, and the catalyst preparation process is complicated, and the active components are expensive.
A hydrogenation catalyst for the preparation of citronellol is developed, which comprises a carbon support and a metal supported on a carbon support, prepared by mixing biomass, pore reamer and water, freeze-drying and calcining, with a metal loading between 5-20%, preferably 8-12%.
The hydrogenation catalyst has the advantages of high conversion rate, high citronellol selectivity, short reaction time, simple post-treatment, low cost and high safety factor. It can effectively improve the yield and selectivity of citronellol and reduce production costs.
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Figure CN120115151A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of citronellol preparation, and in particular to a hydrogenation catalyst for citronellol preparation, a preparation method thereof, and an application thereof. Background Art
[0002] Citronellol is a terpene, also known as vanilla alcohol, with the English name Citronellol and the molecular formula C 10 H 20 O. It is a colorless liquid with a special fresh rose-like aroma and a bitter taste. The boiling point of citronellol is 244.4 °C, the density is 0.859 g / mL, and it is soluble in ethanol and ether. It can be widely used in the fields of edible spices, pharmaceutical raw materials, soaps, skin care products, cosmetics, pesticides, mosquito repellents, etc. Its structure is shown below.
[0003]
[0004] At present, directly selectively reducing citral to obtain citronellol is the mainstream method of current chemical synthesis. The method of hydrogenating citral is complex because its structure contains a conjugated aldehyde group, a conjugated double bond, and an isolated double bond. Therefore, the selective hydrogenation of citral can obtain various complex products: citronellal, citronellol, nerol, geraniol, dihydrocitronellal, tetrahydrocitronellol, menthol, etc. Industrial production plants often use a distillation system to refine the crude product after hydrogenation to obtain the above products with high purity and qualified aroma. However, due to the very close structures and molecular weights of the hydrogenated citral series products, it brings great difficulty to the refining and separation, and high-purity products are often obtained by reducing the yield of the target product. Therefore, it is inevitable to produce more light fractions and heavy fractions, and these fractions often contain a considerable amount of nerol, geraniol, citronellol, citronellal, and unreacted citral and its isomers. And these fractions are usually incinerated as waste liquid. Considering that these waste liquids are derived from expensive geranial and contain a considerable amount of the above components, it is obviously lack of commercial awareness to do so.
[0005] Patent CN114558572A uses citronellol, citronellal, citronellol or geraniol / nerol with Bi 2 O 3 as the carrier and precious metal Ru as the active component to directly catalyze the synthesis of citronellol. Although the yield of citronellol is relatively high, there are problems such as cumbersome catalyst preparation procedures and high price of the active component Ru.
[0006] Therefore, developing a hydrogenation catalyst and applying it to the preparation of citronellol to improve the reaction yield, selectivity, and reduce the reaction cost has better application prospects and value. Summary of the Invention
[0007] To solve the above technical problems, the present invention provides a hydrogenation catalyst for citronellol preparation, its preparation method and application. The hydrogenation catalyst provided by the present invention can be used for the preparation of citronellol, and can solve the problems in the process of preparing geraniol from geranial, such as the difficult treatment, low added value and high energy consumption of the crude product refined front fraction of citronellal, geraniol, nerol and citronellol mixture. Moreover, the hydrogenation catalyst has the advantages of high conversion rate, high selectivity for citronellol, simple post-treatment, low cost and high safety factor.
[0008] To achieve this purpose, the present invention adopts the following technical solutions:
[0009] In the first aspect, the present invention provides a hydrogenation catalyst for citronellol preparation, and the hydrogenation catalyst includes a carbon carrier and a metal supported on the carbon carrier;
[0010] The preparation method of the carbon carrier includes: mixing biomass, a pore-expanding agent and water, and successively performing freeze-drying and calcination to obtain the carbon carrier.
[0011] The carbon carrier in the hydrogenation catalyst provided by the present invention mixes biomass, a pore-expanding agent and water. By introducing the method of freeze-drying before calcination, the carbon carrier is given a rich pore structure. Moreover, the carbon carrier prepared from this biomass contains rich N structures (such as pyridine nitrogen, pyrrole nitrogen, etc.). These N structures form rich "metal-N-C" active sites with metal elements, which is beneficial to anchoring the active sites and improving the catalytic activity.
[0012] The catalyst provided by the present invention can be used for the preparation of citronellol, and has the advantages of high conversion rate, high selectivity for citronellol and short reaction time. Moreover, the catalyst is simple to prepare, has high activity for recycling, greatly reduces the production cost, and has a high application prospect.
[0013] Preferably, the metal includes any one or a combination of at least two of iron, zinc, magnesium, aluminum, nickel, copper, ruthenium, cobalt or gold, and is preferably iron.
[0014] In the present invention, when the supported metal is iron, the obtained catalyst has higher catalytic activity, which is beneficial to improving the yield and selectivity of citronellol.
[0015] Preferably, the loading amount of the metal on the carbon carrier is 5-20% (for example, it can be 5%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, etc.), and is preferably 8-12%.
[0016] In the present invention, when the metal loading amount is within the above-defined range, the catalytic effect of the catalyst can be further improved.
[0017] Preferably, the biomass includes any one or a combination of at least two of soybean meal, peanut meal, willow catkins, fruit shells or ginger.
[0018] Preferably, the pore former includes any one or a combination of at least two of magnesium carbonate, zinc chloride, potassium hydroxide, sodium hydroxide, calcium carbonate, or sodium carbonate, and is preferably magnesium carbonate.
[0019] Preferably, the mass ratio of the biomass to the pore former is 1:(0.1 - 2) (for example, it can be 1:0.1, 1:0.2, 1:0.5, 1:0.8, 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2, etc.), and is preferably 1:(0.5 - 1.5).
[0020] Preferably, the temperature of the freeze-drying is -40 to -10 °C (for example, it can be -40 °C, -30 °C, -20 °C, -10 °C, etc.), and the time of the freeze-drying is 10 - 14 h (for example, it can be 10 h, 11 h, 12 h, 13 h, 14 h, etc.).
[0021] Preferably, the temperature of the calcination is 400 - 800 °C (for example, it can be 400 °C, 500 °C, 600 °C, 700 °C, 800 °C, etc.), and the time of the calcination is 1 - 3 h (for example, it can be 1 h, 1.5 h, 2 h, 2.5 h, 3 h, etc.).
[0022] Preferably, the temperature of the calcination is 500 - 700 °C, and the time of the calcination is 1.5 - 2.5 h.
[0023] In the present invention, when the calcination temperature of the carbon support is within the above-defined range, the catalytic effect of the obtained catalyst is better.
[0024] In a second aspect, the present invention provides a preparation method of a hydrogenation catalyst for the preparation of citronellol according to the first aspect, and the preparation method includes: mixing a carbon support, a metal salt, and water, and obtaining the hydrogenation catalyst after heat preservation treatment.
[0025] Preferably, the metal salt includes any one or a combination of at least two of iron nitrate, zinc chloride, magnesium carbonate, aluminum trioxide, nickel nitrate, copper nitrate, ruthenium trichloride, cobalt nitrate, or gold chloride.
[0026] Preferably, the mixing method includes stirring, and the stirring time is 5 - 10 h (for example, it can be 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, etc.)
[0027] Preferably, the temperature of the heat preservation treatment is 60 - 80 °C (for example, it can be 60 °C, 65 °C, 70 °C, 75 °C, 80 °C, etc.), and the heat preservation time is 10 - 14 h (for example, it can be 10 h, 11 h, 12 h, 13 h, 14 h, etc.).
[0028] Preferably, after the heat preservation treatment, a post-treatment step is further included, and the post-treatment includes: filtering the system, taking the filter cake and drying it to obtain the hydrogenation catalyst.
[0029] In a third aspect, the present invention provides a method for preparing citronellol, and the preparation method includes: mixing a reactant and a hydrogenation catalyst to carry out a hydrogenation reaction to obtain citronellol; the hydrogenation catalyst includes the hydrogenation catalyst for preparing citronellol as described in the first aspect.
[0030] The reactant includes any one or a combination of at least two of nerol, citronellol or citronellal.
[0031] In the prior art, the mixture of citronellal, geraniol, nerol and citronellol generated in the process of preparing geraniol by hydrogenation of geraniol is difficult to treat, has low added value and high energy consumption. In view of this problem, the hydrogenation catalyst provided by the present invention can carry out a hydrogenation reaction with the intermediate products (nerol, citronellol, citronellal) therein as reactants to prepare citronellol, and this preparation method has the advantages of good yield, high selectivity and low cost.
[0032] Preferably, the mass ratio of the reactant to the hydrogenation catalyst is 1:(0.005 - 0.025) (for example, it can be 1:0.005, 1:0.01, 1:0.015, 1:0.02, 1:0.025, etc.), and preferably 1:(0.01 - 0.02).
[0033] Preferably, the temperature of the hydrogenation reaction is 40 - 90 °C (for example, it can be 40 °C, 50 °C, 60 °C, 70 °C, 80 °C, 90 °C, etc.), the pressure of the hydrogenation reaction is 0.5 Mpa - 2 Mpa (for example, it can be 0.5 Mpa, 0.8 Mpa, 1 Mpa, 1.2 Mpa, 1.5 Mpa, 1.8 Mpa, 2 Mpa, etc.), and the time of the hydrogenation reaction is 4 - 6 h (for example, it can be 4 h, 4.5 h, 5 h, 5.5 h, 6 h, etc.).
[0034] Preferably, the temperature of the hydrogenation reaction is 50 - 70 °C, the pressure of the hydrogenation reaction is 1 Mpa - 2 Mpa, and the time of the hydrogenation reaction is 4.5 - 5.5 h.
[0035] In the present invention, when the conditions of the hydrogenation reaction are within the above-defined range, this preparation method has higher yield and selectivity.
[0036] Compared with the prior art, the present invention has at least the following beneficial effects:
[0037] The hydrogenation catalyst provided by the present invention can be used for the preparation of citronellol, and has the advantages of high yield, high selectivity, short reaction time, and simple post-treatment. Moreover, the preparation method of the catalyst is simple, easy to recycle and reuse, and the catalytic activity remains basically unchanged. There are no safety risks in the preparation of the catalyst and the subsequent preparation of citronellol, and it has high industrial application prospects. Description of the Drawings
[0038] Figure 1 It is a reaction flow chart.
[0039] Figure 2 It is the SEM diagram of the carbon support Mg 1 -SMC-600 prepared in Example 1-1. Detailed Embodiments
[0040] The technical solutions of the present invention will be further described below with reference to the drawings and through specific embodiments. However, the following examples are only simple examples of the present invention and do not represent or limit the scope of the protection of the present invention. The scope of protection of the present invention shall be subject to the claims.
[0041] The "pre-fraction" used in the following examples is the pre-fraction after the hydrogenation reaction of geranial, including nerol, citronellol, and citronellal;
[0042] The preparation method of the pre-fraction is as follows: 200 g of geranial and 1.5 g of (Ru-Co-Cu / AC) catalyst are mixed, and hydrogen is intermittently introduced (2.0 Mpa) at 125 °C for 10 h. After the hydrogenation reaction to generate geraniol, nerol, citronellol, and citronellal, the reaction solution is subjected to desolvation and deweighting to obtain a crude product. The crude product is separated by a high-efficiency rectification column to separate geraniol from the pre-fraction (nerol, citronellol, and citronellal), and the pre-fraction is obtained by overhead distillation.
[0043] Figure 1 It shows the reaction process of the present invention. Geranial is used as the reactant of the present invention, and after hydrogenation reaction, nerol, citronellol, and citronellal are obtained. After hydrogenation reaction, citronellol and a small amount of tetrahydrogeraniol are obtained.
[0044] Preparation of Carbon Support in Example 1
[0045] Example 1-1
[0046] This example provides a preparation method of a carbon support: Take 50 g of magnesium carbonate, 50 g of soybean meal powder, and 50 g of water and put them into a beaker for stirring and fully mixing. After mixing evenly, put them into petri dishes respectively, seal them with tin foil, make holes, and perform freeze-drying at -20 °C for 12 h. The obtained solid is put into an ark, and the ark is put into a tubular furnace and heated to 600 °C at a rate of 5 °C / min, kept warm for 2 h, and then taken out after cooling to name the carbon support as Mg 1 -SMC-600.
[0047] Figure 1 is Mg 1 SEM image of -SMC-600 shows that it has a very rich pore structure.
[0048] Example 1-2
[0049] This example provides a method for preparing a carbon carrier: Take 75 g of magnesium carbonate, 50 g of peanut powder and 50 g of water, put them into a beaker and stir well. After mixing evenly, put them into petri dishes respectively. Seal with tin foil, punch holes, and freeze-dry at -30 °C for 10 h. Put the obtained solid into an ark, put the ark into a tube furnace and heat it to 500 °C at a rate of 5 °C / min, keep it warm for 2.5 h, cool it down and take out the carbon carrier, named Mg 1.5 -SMC-500.
[0050] Example 1-3
[0051] This example provides a method for preparing a carbon carrier: Take 25 g of magnesium carbonate, 50 g of soybean meal powder and 50 g of water, put them into a beaker and stir well. After mixing evenly, put them into petri dishes respectively. Seal with tin foil, punch holes, and freeze-dry at -10 °C for 14 h. Put the obtained solid into an ark, put the ark into a tube furnace and heat it to 700 °C at a rate of 5 °C / min, keep it warm for 1.5 h, cool it down and take out the carbon carrier, named Mg 0.5 -SMC-700.
[0052] Example 1-4
[0053] This example provides a method for preparing a carbon carrier. The only difference from Example 1-1 is that magnesium carbonate is replaced by zinc chloride, and the others refer to Example 1-1. The obtained carbon carrier is named Zn 1 -SMC-600.
[0054] Example 1-5
[0055] This example provides a method for preparing a carbon carrier. The only difference from Example 1-1 is that magnesium carbonate is replaced by sodium hydroxide, and the others refer to Example 1-1. The obtained carbon carrier is named Na 1 -SMC-600.
[0056] Example 1-6
[0057] This example provides a method for preparing a carbon carrier. The only difference from Example 1-1 is that the ark is put into a tube furnace and heated to 400 °C, and the others refer to Example 1-1. The obtained carbon carrier is named Mg 1 -SMC-400.
[0058] Examples 1 - 7
[0059] This example provides a method for preparing a carbon support. The difference from Example 1 - 1 is only that the ark is placed in a tubular furnace and heated to 800 °C, and the others refer to Example 1 - 1. The obtained carbon support is named Mg 1 -SMC-800.
[0060] Comparative Example 1 - 1
[0061] This comparative example provides a method for preparing a carbon support. The difference from Example 1 - 1 is only that freeze-drying is not carried out, that is, magnesium carbonate and soybean meal powder are directly mixed and placed in the ark, and then the ark is placed in a tubular furnace and heated to 600 °C at a rate of 5 °C / min, held for 2 h, cooled and then the carbon support is taken out. The obtained carbon support is named Mg 1 -SMC-600-1.
[0062] Preparation of hydrogenation catalyst in Example 2
[0063] Example 2 - 1
[0064] This example provides a method for preparing a hydrogenation catalyst: Dissolve 4 g of Fe(NO 3 ) 3 in 100 g of water. After complete dissolution, add 8.361 g of Mg 3 ) 3 -SMC-600 (provided by Example 1 - 1) to the Fe(NO 1 ) 1 aqueous solution, stir for 7 h, then place the above mixture in a 70 °C water bath and keep it at a constant temperature for 12 h. After cooling, filter, and place the filter cake in a 110 °C forced-air drying oven and dry for 12 h to obtain a 10% Fe-Mg
[0065] -SMC-600 catalyst.
[0066] This example provides a method for preparing a hydrogenation catalyst: Dissolve 3 g of Fe(NO 3 ) 3 in 100 g of water. After complete dissolution, add 8.221 g of Mg 3 ) 3 -SMC-500 (provided by Example 1 - 2) to the Fe(NO 1.5 ) 1.5 aqueous solution, stir for 7 h, then place the above mixture in a 60 °C water bath and keep it at a constant temperature for 14 h. After cooling, filter, and place the filter cake in a 110 °C forced-air drying oven and dry for 12 h to obtain an 8% Fe-Mg
[0067] Example 2-3
[0068] This example provides a preparation method of a hydrogenation catalyst: Dissolve 4 g of Fe(NO 3 ) 3 in 100 g of water. After complete dissolution, add 7.261 g of Mg 3 ) 3 -SMC-700 (provided in Example 1-3) to the aqueous solution of Fe(NO 0.5 -SMC-700, stir for 7 h, then place the above mixture in a water bath at 80 °C and keep it at a constant temperature for 10 h. After cooling, filter, and place the filter cake in a forced-air drying oven at 110 °C and dry for 12 h to obtain a 12% Fe-Mg 0.5 -SMC-700 catalyst.
[0069] Examples 2-4 to 2-7, Comparative Example 2-1
[0070] The above examples and comparative examples respectively provide a preparation method of a hydrogenation catalyst. The difference from Example 2-1 is only that the carbon carriers provided in Example 1-1 are respectively replaced with the carbon carriers provided in Example 1-4, Example 1-5, Example 1-6, Example 1-7, and Comparative Example 1-1. The obtained catalysts are respectively named 10% Fe-Zn 1 -SMC-600, 10% Fe-Na 1 -SMC-600, 10% Fe-Mg 1 -SMC-400, 10% Fe-Mg 1 -SMC-800, 10% Fe-Mg 1 -SMC-600-1.
[0071] Example 2-8
[0072] This example provides a preparation method of a hydrogenation catalyst. The difference from Example 2-1 is only the different iron loadings. Specifically: Dissolve 2 g of Fe(NO 3 ) 3 in 100 g of water. After complete dissolution, add 8.835 g of Mg 3 ) 3 -SMC-600 (provided in Example 1-1) to the aqueous solution of Fe(NO 1 -SMC-600, stir for 7 h, then place the above mixture in a water bath at 70 °C and keep it at a constant temperature for 12 h. After cooling, filter, and place the filter cake in a forced-air drying oven at 110 °C and dry for 12 h to obtain a 5% Fe-Mg 1 -SMC-600 catalyst.
[0073] Example 2-9
[0074] This embodiment provides a method for preparing a hydrogenation catalyst, which is only different from that of Example 2-1 in the iron loading amount. Specifically: Dissolve 4 g of Fe(NO 3 ) 3 in 100 g of water. After complete dissolution, add 5.246 g of Mg 3 ) 3 -SMC-600 (provided by Example 1-1) to the Fe(NO 1 ) 1 aqueous solution, stir for 7 h, then place the above mixture in a water bath at 70 °C and keep it constant for 12 h. After cooling, filter, and place the filter cake in a blast drying oven at 110 °C and dry for 12 h to obtain a 15% Fe-Mg
[0075] -SMC-600 catalyst.
[0076] This embodiment provides a method for preparing a hydrogenation catalyst, which is only different from that of Example 2-1 in that the loaded metal element is Ru. Specifically: Dissolve 2 g of RuCl 3 in 100 g of water. After complete dissolution, add 8.361 g of Mg 3 -SMC-600 (provided by Example 1-1) to the RuCl 1 aqueous solution, stir for 7 h, then place the above mixture in a water bath at 70 °C and keep it constant for 12 h. After cooling, filter, and place the filter cake in a blast drying oven at 110 °C and dry for 12 h to obtain a 10% Ru-Mg 1 -SMC-600 catalyst.
[0077] Example 2-11
[0078] This embodiment provides a method for preparing a hydrogenation catalyst, which is only different from that of Example 2-1 in that the loaded metal element is Ni. Specifically: Dissolve 2.85 g of Ni(NO 3 ) 2 in 100 g of water. After complete dissolution, add 8.361 g of Mg 3 ) 2 -SMC-600 (provided by Example 1-1) to the Ni(NO 1 ) 1 aqueous solution, stir for 7 h, then place the above mixture in a water bath at 70 °C and keep it constant for 12 h. After cooling, filter, and place the filter cake in a blast drying oven at 110 °C and dry for 12 h to obtain a 10% Ni-Mg
[0079] For the hydrogenation catalyst provided by the present invention, the metal content on the carbon carrier is determined by the ICP method.
[0080] Example 3 Preparation of Citronellol
[0081] Example 3-1
[0082] This example provides a method for preparing citronellol: First, add 2.25 g of 10% Fe-Mg 1 -SMC-600 (provided by Example 2-1) and 150 g of the pre-fraction to a 1000 ml hydrogenation reaction autoclave. Seal the autoclave and displace it with nitrogen and hydrogen three times each. Then start heating and stirring. When the temperature rises to 60 °C, charge hydrogen to 2 Mpa and maintain it for 5 h until the reaction ends to obtain the crude product.
[0083] Example 3-2
[0084] This example provides a method for preparing citronellol: First, add 3 g of 8% Fe-Mg1.5-SMC-500 (provided by Example 2-2) and 150 g of the pre-fraction to a 1000 ml hydrogenation reaction autoclave. Seal the autoclave and displace it with nitrogen and hydrogen three times each. Then start heating and stirring. When the temperature rises to 50 °C, charge hydrogen to 1 Mpa and maintain it for 5.5 h until the reaction ends to obtain the crude product.
[0085] Example 3-3
[0086] This example provides a method for preparing citronellol: First, add 1.5 g of 12% Fe-Mg1.5-SMC-500 (provided by Example 2-3) and 150 g of the pre-fraction to a 1000 ml hydrogenation reaction autoclave. Seal the autoclave and displace it with nitrogen and hydrogen three times each. Then start heating and stirring. When the temperature rises to 70 °C, charge hydrogen to 1 Mpa and maintain it for 4.5 h until the reaction ends to obtain the crude product.
[0087] Examples 3-4 to 3-9, Comparative Example 3-1
[0088] The above examples and comparative examples respectively provide a method for preparing citronellol, and the difference from Example 3-1 is only that the catalysts used in Example 3-1 are respectively replaced with 10% Fe-Zn 1 -SMC-600 provided by Example 2-4, 10% Fe-Na 1 -SMC-600 provided by Example 2-5, 10% Fe-Mg 1 -SMC-400 provided by Example 2-6, 10% Fe-Mg 1 -SMC-800 provided by Example 2-7, 5% Fe-Mg 1 -SMC-600 provided by Example 2-8, 15% Fe-Mg 1 -SMC-600 provided by Example 2-9, 10% Fe-Mg provided by Comparative Example 2-1 1-SMC-600-1, for other references, see Example 3-1.
[0089] Example 3-10
[0090] This example provides a method for preparing citronellol, which is only different from Example 3-1 in that the reaction temperature is adjusted to 40 °C, and for other references, see Example 3-1.
[0091] Example 3-11
[0092] This example provides a method for preparing citronellol, which is only different from Example 3-1 in that the reaction temperature is adjusted to 80 °C, and for other references, see Example 3-1.
[0093] Example 3-12
[0094] This example provides a method for preparing citronellol, which is only different from Example 3-1 in that the amount of the catalyst is adjusted to 1.5 g and the pressure of the charged hydrogen is adjusted to 1 Mpa, and for other references, see Example 3-1.
[0095] Example 3-13
[0096] This example provides a method for preparing citronellol, which is only different from Example 3-1 in that the amount of the catalyst is adjusted to 3 g and the pressure of the charged hydrogen is adjusted to 1 Mpa, and for other references, see Example 3-1.
[0097] Example 3-14
[0098] This example provides a method for preparing citronellol, which is only different from Example 3-1 in that the pressure of the charged hydrogen is adjusted to 1 Mpa, and for other references, see Example 3-1.
[0099] Example 3-15
[0100] This example provides a method for preparing citronellol, which is only different from Example 3-1 in that the pressure of the charged hydrogen is adjusted to 1.5 Mpa, and for other references, see Example 3-1.
[0101] Comparative Example 3-2
[0102] This comparative example provides a method for preparing citronellol, which is only different from Example 3-1 in that the catalyst is replaced with a carbon support Mg without loaded metal 1 -SMC-600 (provided by Example 1-1), for other references, see Example 3-1.
[0103] Test Example 1
[0104] The crude products obtained after the reactions in the above Examples 3-1 to 3-15 and Comparative Examples 3-1 to 3-2 were subjected to GC analysis, and the results are shown in Table 1.
[0105] Table 1
[0106]
[0107]
[0108] It can be seen from the data in Table 1 that:
[0109] (1) It can be seen from Examples 3-1 to 3-15 that the hydrogenation catalyst provided by the present invention can be used for the preparation of citronellol, and has the advantages of high yield, high selectivity and low cost.
[0110] (2) By comparing Example 3-1 with Examples 3-4 to 3-5, it can be seen that the hydrogenation catalyst adopted in the present invention uses a specific pore-expanding agent, which helps to enrich the pore structure of the carbon carrier, thereby improving the yield and selectivity of the hydrogenation catalyst;
[0111] By comparing Example 3-1 with Examples 3-6 to 3-7, it can be seen that when the calcination temperature of the carbon carrier is too high or too low in the present invention, changes such as pore collapse inside the carrier itself and smaller specific surface area will occur, and the active component cannot react fully with the raw material. An appropriate calcination temperature is beneficial to improving the yield and selectivity of the hydrogenation catalyst;
[0112] By comparing Example 3-1 with Examples 3-8 to 3-9, it can be seen that when the metal loading amount on the carbon carrier is too high or too low in the present invention, problems such as agglomeration of the active component on the carrier surface and a large loss of active sites will occur. An appropriate metal loading amount is beneficial to improving the yield and selectivity of the hydrogenation catalyst;
[0113] By comparing Example 3-1 with Examples 3-10 to 3-11, it can be seen that when the hydrogenation temperature for the preparation of citronellol is too high or too low in the present invention, both the reaction yield and the selectivity of citronellol will decrease.
[0114] (3) By comparing Example 3-1 with Comparative Example 3-1, it can be seen that the present invention prepares the carbon carrier by combining freeze-drying and calcination, which can enrich the pore structure of the carbon carrier, thereby improving the yield and selectivity of the hydrogenation catalyst;
[0115] By comparing Example 3-1 with Comparative Example 3-2, it can be seen that the hydrogenation catalyst with metal loaded on the carbon carrier adopted in the present invention has the advantages of high yield and high selectivity. When no metal is loaded on the carbon carrier, the catalytic activity decreases.
[0116] Test Example 2
[0117] The hydrogenation catalyst collected after the reaction in Example 3-1 was subjected to a recycling test according to the method of Example 3-1. The experimental data for verifying the life of the hydrogenation catalyst are shown in Table 2.
[0118] Table 2
[0119] Number of applications Conversion rate / % Citronellol selectivity / % Tetrahydrogeraniol selectivity / % Scrap rate / % 1 99.8 99.8 0.1 0.18 2 99.7 99.8 0.1 0.1 3 99.7 99.8 0.12 0.15 4 99.7 99.8 0.15 0.1 5 99.7 99.8 0.1 0.15 10 99.6 99.6 0.15 0.26 15 99.7 99.7 0.20 0.18 20 99.5 99.7 0.25 0.30 25 99.4 99.7 0.15 0.29 30 99.5 99.7 0.20 0.22
[0120] The data results in Table 2 show that the hydrogenation catalyst provided by the present invention can be recycled ≥30 times, and the activity of the catalyst remains basically unchanged, which can be recycled repeatedly, greatly reducing the production cost.
[0121] The applicant declares that the above description is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived within the technical scope disclosed by the present invention fall within the protection scope and the disclosure scope of the present invention.
Claims
1. A hydrogenation catalyst for the preparation of citronellol, characterized in that: The hydrogenation catalyst comprises a carbon support and a metal supported on the carbon support; The preparation method of the carbon carrier comprises: mixing biomass, a pore-enlarging agent and water, and sequentially performing freeze-drying and calcination to obtain the carbon carrier.
2. The hydrogenation catalyst according to claim 1, characterized in that The metal includes any one or a combination of at least two of iron, zinc, magnesium, aluminum, nickel, copper, ruthenium, cobalt or gold, preferably iron; Preferably, the metal loading on the carbon carrier is 5-20%, preferably 8-12%.
3. The hydrogenation catalyst according to claim 1 or 2, characterized in that The biomass includes any one of soybean meal, peanut meal, catkins, husks or ginger, or a combination of at least two thereof; Preferably, the pore expanding agent includes any one of magnesium carbonate, zinc chloride, potassium hydroxide, sodium hydroxide, calcium carbonate or sodium carbonate, or a combination of at least two thereof, preferably magnesium carbonate.
4. The hydrogenation catalyst according to any one of claims 1 to 3, characterized in that The mass ratio of the biomass to the pore-enlarging agent is 1:(0.1-2), preferably 1:(0.5-1.5); Preferably, the freeze-drying temperature is -40 to -10°C, and the freeze-drying time is 10 to 14 hours; Preferably, the calcination temperature is 400-800°C, and the calcination time is 1-3h; Preferably, the calcination temperature is 500-700° C., and the calcination time is 1.5-2.5 h.
5. A method for preparing a hydrogenation catalyst for preparing citronellol according to any one of claims 1 to 4, characterized in that: The preparation method comprises: mixing a carbon carrier, a metal salt and water, and performing heat preservation treatment to obtain the hydrogenation catalyst.
6. The preparation method according to claim 5, characterized in that: The metal salt includes any one or a combination of at least two of ferric nitrate, zinc chloride, magnesium carbonate, aluminum oxide, nickel nitrate, copper nitrate, ruthenium trichloride, cobalt nitrate or gold chloride; Preferably, the temperature of the heat preservation treatment is 60-80°C, and the heat preservation time is 10-14h.
7. A method for preparing citronellol, characterized in that: The preparation method comprises: mixing reactants and a hydrogenation catalyst to carry out a hydrogenation reaction to obtain citronellol; the hydrogenation catalyst comprises the hydrogenation catalyst for preparing citronellol according to any one of claims 1 to 4; The reactant includes any one of nerol, citronellol or citronellal, or a combination of at least two of them.
8. The preparation method according to claim 7, characterized in that: The mass ratio of the reactants to the hydrogenation catalyst is 1:(0.005-0.025), preferably 1:(0.01-0.02).
9. The preparation method according to claim 7 or 8, characterized in that: The temperature of the hydrogenation reaction is 40-90° C., the pressure of the hydrogenation reaction is 0.5 MPa-2 MPa, and the time of the hydrogenation reaction is 4-6 h.
10. The preparation method according to claim 9, characterized in that: The temperature of the hydrogenation reaction is 50-70° C., the pressure of the hydrogenation reaction is 1Mpa-2Mpa, and the time of the hydrogenation reaction is 4.5-5.5h.