Hydrogenation catalyst and preparation method thereof, and method for synthesizing alicyclic compound by hydrogenation of aromatic compound

Abstract

The invention discloses a hydrogenation catalyst and a preparation method thereof, and a method for synthesizing an alicyclic compound by hydrogenation of an aromatic compound. The hydrogenation catalyst is a supported Ru-Rh bimetallic catalyst with high activity, high selectivity and long service life. Compared with the prior art, the catalyst prepared by the method is high in universality and wide in applicable process range, can catalyze hydrogenation of various aromatic compounds to obtain corresponding alicyclic compounds in a high-activity and high-selectivity manner, and has special diastereoselectivity in catalysis of hydrogenation of some aromatic compounds containing multiple substituents.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of catalytic hydrogenation, and particularly relates to a hydrogenation catalyst and a method for synthesizing alicyclic compounds by hydrogenation of aromatic compounds using the catalyst. BACKGROUND

[0002] Common aromatic compounds include aromatic hydrocarbons, phenols, aromatic amines, and aromatic compounds with carboxyl, halogen or other substituents on the aromatic ring. Aromatic hydrocarbons mainly include benzene, and derivatives of benzene such as toluene, xylene, ethylbenzene, mesitylene, cumene, biphenyl, and other compounds not containing elements other than carbon and hydrogen. In addition, there are condensed ring compounds such as naphthalene, anthracene, and phenanthrene, and their derivatives. Aromatic hydrocarbons are carcinogenic substances that can accumulate in the environment and seriously harm human health. In addition, high content of aromatic hydrocarbons in fuel oil can also affect the performance of fuel oil: the cetane number of diesel oil decreases with the increase of aromatic hydrocarbon content, which can easily lead to engine knock, thereby affecting the combustion efficiency and shortening the service life of the engine. For gasoline, although aromatic hydrocarbons are an indispensable important component, their increase can help improve the octane number of gasoline, but high aromatic hydrocarbon content can easily lead to incomplete combustion of gasoline, and the resulting carbon deposits are not conducive to engine operation, and the particulate matter discharged with the exhaust gas seriously affects air quality. Therefore, converting aromatic hydrocarbons in gasoline and diesel oil into corresponding alicyclic compounds through catalytic hydrogenation not only improves the combustion efficiency, but also effectively improves air environmental quality, creating significant social and economic benefits. In addition, alicyclic hydrocarbon compounds such as methylcyclohexane and dimethylcyclohexane can also be used to manufacture solvents, lubricants, high-grade fuels, and pharmaceutical intermediates, etc.

[0003] Common phenolic compounds mainly include phenol, p-cresol, o / p-tert-butyl phenol, p-methoxyphenol, o / m / p-hydroquinone, etc. Phenolic compounds have a wide range of applications in the fields of disinfection, preservation, pain relief, antifungal, insecticide, medicine, food, agriculture, cosmetics, dyes, plastics, coatings, etc. Phenolic compounds are malodorous substances that can enter the human body through the digestive tract, respiratory tract and skin, bind to proteins in cell protoplasm, cause cells to lose activity, and in severe cases, cause spinal cord irritation and lead to systemic poisoning. By hydrogenating certain phenolic compounds to convert them into corresponding alicyclic alcohol compounds, not only is their toxicity greatly reduced, but the obtained alicyclic alcohol compounds also have a wide range of applications in many fields. For example, 4-tert-butylcyclohexanol is a commonly used daily chemical fragrance additive. Adding this substance to fragrances can effectively inhibit discoloration, and it has been widely used in the formulation of daily chemical fragrances. 1,4-Cyclohexanediol is an important organic synthesis raw material and is widely used in many aspects of organic synthesis. For example, in drug synthesis, it can be used in the synthesis of anticancer drugs, HMG-CoA reductase, succinyl sulfathiazole and benzotriazole drugs, etc.; in fine chemical industry, it can be used in the synthesis of liquid crystal materials, organic electrical materials, biological controller markers, etc. 2,6-di-tert-butyl-4-methylcyclohexanol is mainly used in the fields of photography, printing and dyeing, pharmaceutical and pesticide intermediates, etc. Hydrogenated bisphenol A is a key raw material monomer for producing hydrogenated bisphenol A type special epoxy resin. Its molecular structure is stable, can effectively improve the light, heat stability and weather resistance of synthetic epoxy resin, expand the application fields of epoxy resin products, and can be used in the fields of electronic packaging materials, electronic and electrical materials, sealants, automotive coatings, etc. Compared with bisphenol A, the performance of its downstream products is greatly improved, and it has almost no toxicity.

[0004] Common aromatic amine compounds include aniline, 4-methylaniline, 4-tert-butylaniline, o / m / p-phenylenediamine, 4,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, m / p-phenylenediamine, 2,4-diaminotoluene, and 2,6-diaminotoluene. They are mainly used in epoxy curing agents and polyurethane materials, and can also be used as intermediates in dyes and pharmaceuticals. These compounds generally possess high toxicity and high melting points, and are easily oxidized upon prolonged exposure to air, causing them to yellow, which limits their downstream applications. Alicyclic amines obtained by hydrogenating these aromatic amine compounds, such as 4-methylcyclohexylamine, 4-tert-butylcyclohexylamine, 1,2-diaminocyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, 4,4'-diaminodicyclohexylmethane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, 1,3-cyclohexanedimethylamine, 1,4-cyclohexanedimethylamine, 4-methyl-1,3-cyclohexanediamine, and 2-methyl-1,3-cyclohexanediamine, typically possess advantages such as low toxicity, low freezing point, and excellent resistance to yellowing. They can be widely used in pharmaceuticals, high-end polyurethanes, epoxy resin composites, and specialty nylons.

[0005] If an aromatic compound contains two or more substituents on its benzene ring, the alicyclic compound obtained by hydrogenation is usually a mixture of various diastereomers. The content of certain isomers in the product often plays a decisive role in its application performance and price. For example, cis-4-tert-butylcyclohexanol is a major raw material for the production of high-grade fragrances, soaps, and shampoos, while the presence of trans-4-tert-butylcyclohexanol will significantly reduce the fragrance of the product. Similarly, 2-tert-butylcyclohexanol with high cis content is also an important raw material for preparing high-grade fragrances; cis-1,4-cyclohexanediol has very important value and unique properties in chiral reagents and polymers, and its synthesis methods are receiving increasing attention; hydrogenated bisphenol A has three diastereomers: cis-cis, cis-trans, and trans-trans. Studies have shown that epoxy resins synthesized from hydrogenated bisphenol A with high trans-trans isomer content have excellent thermal and chemical stability, making them particularly suitable for outdoor applications and widely applicable in modern industrial fields such as aerospace, microelectronics, machinery, and automobiles; trans-4-methylcyclohexylamine is a key intermediate in the synthesis of glimepiride, a drug for treating type II diabetes; 1,3-cyclohexanedimethylamine products with high cis content are more advantageous for applications in isocyanates and nylon, and polyamides synthesized from it have high crystallinity and superior performance; conversely, 1,4-cyclohexanedimethylamine... A higher content of the trans isomer significantly improves its melting point and thermal stability, making it more suitable for applications in the polyamide field. The hydrogenation product of 4,4'-diaminodicyclohexylmethane mainly contains three isomers: trans-trans, trans-cis, and cis. Lower content of the trans-trans isomer results in a lower freezing point, which is more beneficial for applications in epoxy curing agents and polyurethanes. High levels of trans-trans in 4,4'-diaminodicyclohexylmethane are even more advantageous. Applications in the nylon field; the hydrogenation product of 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, mainly contains eight diastereomers. The freezing point of the product decreases as the content of the key isomer 3e,4e,3'e,4'a-3,3'-dimethyl-4,4'-diaminodicyclohexylmethane decreases, and the product with a low freezing point is more conducive to its production, storage, transportation and use.

[0006] Aromatic compounds, due to the stable electronic structure of their aromatic rings and the significant steric hindrance of their substituents, generally exhibit low hydrogenation reactivity, typically requiring harsh reaction conditions such as high temperature and high pressure. Furthermore, phenols and amines, containing highly polar CO and CN bonds, are prone to side reactions such as deoxygenation and deamination during hydrogenation, significantly reducing product yields. The key to solving these problems lies in developing catalysts with high activity, high selectivity, and long lifetimes. Additionally, since hydrogenation products generally consist of two or more diastereomers, selectively controlling key isomer parameters in the product through the combination of catalysts and hydrogenation processes is also a crucial issue that urgently needs to be addressed. The following are reports on various existing technologies for the catalytic hydrogenation of aromatic compounds to synthesize alicyclic compounds:

[0007] Patent CN101575257A reports a method for preparing methylcyclohexane by catalytic hydrogenation of toluene. Using commercially available amorphous nickel as a catalyst and cyclohexane as a solvent, under hydrogenation conditions of reaction temperature 130-180℃ and pressure 5-8MPa, the toluene conversion rate reaches over 99%.

[0008] Patent CN1098333C reports a method for the catalytic hydrogenation of trimethylcyclohexane to trimethylbenzene. Using titanium dioxide or alumina as a support, and through an impregnation method, with potassium borohydride or sodium hypophosphite as a reducing agent, single or mixed supported Ni / Co amorphous alloy catalysts containing B or P were prepared. By adjusting the pre-reduction temperature and hydrogenation reaction temperature of the catalyst, the conversion rate of 1,2,4-trimethylbenzene and 1,3,5-trimethylbenzene to hydrogenation reached 100%.

[0009] Patent CN106518601B reports a method for synthesizing cyclohexylbenzene by hydrogenation alkylation. The method uses organosilicon microporous zeolite as a support, with one or more of Pd, Pt, Ru, Rh, and Ir as active components, and one or more of V, Cr, Mn, Fe, Co, Ni, Cu, or Zn as auxiliary agents. A catalyst is prepared by impregnation. However, this catalyst exhibits low activity in catalyzing the hydrogenation alkylation of benzene, resulting in a benzene conversion rate of less than 50%.

[0010] Patent CN115739116A reports a catalyst, its preparation and regeneration methods, and a method for producing hydrogenated bisphenol A. A supported multi-metal catalyst composed of four metals—Ru, Pd, Ni, and Cu—was prepared using alumina and silica as supports via ultrasonic impregnation and infrared drying. Using this catalyst, the hydrogenation of bisphenol A achieves a yield of over 98%, with the trans-trans isomer content reaching 45%.

[0011] Patent CN110526799A reports a reaction process for the continuous catalytic hydrogenation of 2,6-di-tert-butylphenol via a two-stage fixed bed. The first stage of the fixed bed uses a Ni / Al2O3 catalyst, and the second stage uses a Ru / Al2O3 or Ru / Al2O3 catalyst. The final result is that the conversion rate of the feedstock and the selectivity of the product 2,6-di-tert-butyl-4-methylcyclohexanol both reach more than 90%.

[0012] Patent CN113292397B reports a supported dual transition metal catalyst prepared by impregnation using a mixture of γ-Al2O3 with TiO2, MgO, etc. as a support. The catalyst is used to catalyze the hydrogenation of hydroquinone to 1,4-cyclohexanediol, with a conversion rate and selectivity of over 90%.

[0013] Patent CN110743546A reports a catalyst, preparation method, and application for the hydrogenation of tert-butylphenol to cis-p-tert-butylcyclohexanol. The catalyst uses activated carbon, γ-Al₂O₃, or aluminosilicate molecular sieves as supports, Ru and Pd bimetallic compounds as active components, and one or more non-metallic additives selected from P, F, and B, and one or more metallic additives selected from Mn, Zr, Wu, V, Nb, and Ti. Using this catalyst, the molar conversion of tert-butylphenol exceeds 99.5%, the selectivity for tert-butylcyclohexanol in the product exceeds 99%, and the content of cis-p-tert-butylcyclohexanol in the product exceeds 80%.

[0014] Patent US6489520B2 reports a method for hydrogenating 2-tert-butylphenol using a Ni / Fe bimetallic Raney catalyst, which can achieve a 100% conversion rate of the raw material and a cis:trans ratio of 95:5 in the product.

[0015] Patent CN109678726B reports a method for hydrogenating 4-methylaniline using supported ruthenium (Ru / C or Ru / Al2O3) as a catalyst and adding alkali metal additives (such as lithium metaborate, sodium hydroxide, potassium hydroxide, sodium methoxide, potassium tert-butoxide) to obtain a product with a 4-methylcyclohexylamine content of over 90%.

[0016] Patent CN102690204A reports a method for preparing cyclohexanediamine, using a conventional impregnation method to prepare a 5% Ru-2% Re / coconut shell carbon catalyst. Using this catalyst, with isopropanol as the solvent and distilled water, NaNO2, and a small amount of liquid ammonia as auxiliaries, hydrogenation of o-phenylenediamine was performed, achieving a conversion rate of 96.8% and a selectivity of 82.1% for the product 1,2-diaminocyclohexane. Under the same conditions, hydrogenation of m-phenylenediamine was performed, achieving a conversion rate of 98.7% and a selectivity of 90.7% for the product 1,3-diaminocyclohexane.

[0017] Patent CN109772312A prepared a 4% Ru / hydrotalcite catalyst using an impregnation method and modified the catalyst with lithium hydroxide to catalyze the hydrogenation of m-phenylenediamine, achieving a feed conversion rate of 100% and a selectivity of 96.1% for 1,3-cyclohexanedimethylamine.

[0018] Patent US9873658B2 reports a method for the hydrogenation of 4,4'-diaminodiphenylmethane using a 10% Ru / ZrO2 catalyst prepared by impregnation. In its examples, the effect of different hydrogenation temperatures was investigated. At 120°C and 240 min, the feed conversion was 100%, the selectivity of the product 4,4'-diaminodicyclohexylmethane was 95%, and the content of the trans-trans isomer in the product was 19%. Under the same conditions, when the reaction temperature was lowered to 100°C, although the content of the trans-trans isomer in the product decreased to 10%, the feed conversion and product selectivity were only 67% and 14%, respectively. When the temperature was increased to 140°C, the feed conversion and product selectivity were 100% and 93%, respectively, but the content of the trans-trans isomer in the product increased significantly, reaching 49%.

[0019] Patent CN102030657A discloses a method for preparing 3,3'-dimethyl-4,4'-diaminodiphenylmethane by hydrogenation of 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane using a SiO2 or activated carbon-supported Ru or Ru-Rh bimetallic catalyst prepared by impregnation. The product yield reaches over 95%, and the content of 3e,4e,3'e,4'a-3,3'-dimethyl-4,4'-diaminodicyclohexylmethane in the product is less than or equal to 26%.

[0020] Patent CN106994344A reports the synthesis of ruthenium catalysts supported on alumina, activated carbon, and titanium dioxide using one or more of cerium, manganese, and lanthanum as auxiliary agents. Methylcyclohexanediamine was prepared by hydrogenation of a mixture of 2,4-diaminotoluene and 2,6-diaminotoluene in an 80:20 ratio. The catalyst was reused in 20 batches, with a raw material conversion rate of over 99% and a product selectivity of over 95%.

[0021] Patent CN1332914C reports a method for hydrogenating aromatic compounds with at least one hydroxyl group or at least one amino group attached to the aromatic ring to obtain the corresponding alicyclic alcohols or alicyclic amines. A catalyst-active precursor solution is mixed with an organic polymer to obtain a swollen polymer. This swollen polymer is then mixed with a support, and the mixture is sequentially molded, dried, and calcined to obtain a Ru / Al2O3 catalyst. Using this catalyst, the hydrogenation of aniline achieves a selectivity of over 99% for the product cyclohexylamine; the hydrogenation of p-tert-butylphenol achieves a selectivity of 99.2% for the product 4-tert-butylcyclohexanol, with a cis / trans isomer ratio of 48 / 52; and the hydrogenation of bisphenol A achieves a selectivity of 98.7% for the product hydrogenated bisphenol A.

[0022] In summary, the existing technologies for the catalytic hydrogenation of aromatic compounds to synthesize alicyclic compounds mainly have the following problems: (1) Hydrogenation of aromatics generally uses Ni-based catalysts, which require harsh reaction conditions such as high temperature and high pressure; (2) Hydrogenation of phenolic compounds also mainly uses Ni-based catalysts, and the reaction conditions are also relatively harsh. Generally, certain promoters need to be added to the reaction system to improve activity and selectivity, and the key isomer indicators in the product are difficult to control effectively, often requiring complex post-processing; (3) Existing technologies for the hydrogenation of amine compounds generally use Ru-based catalysts and add promoters such as LiOH and NaNO2 to suppress side reactions such as deamination, but there are still some problems. The problems include: (4) low catalyst activity and unsatisfactory control of key isomer indicators for some products; (5) poor catalyst versatility and narrow application range. For different aromatic hydrogenation substrates, it is difficult to achieve high-activity and high-selectivity hydrogenation of various aromatic compounds by simply changing the hydrogenation process without changing the catalyst; (6) existing technologies often only focus on indicators such as raw material conversion rate, product selectivity and yield, while ignoring the key isomer indicators in the product. Moreover, it is usually difficult to effectively control the key isomer indicators in the product while achieving high-activity and high-selectivity hydrogenation, so that the alicyclic products obtained have better application performance. Summary of the Invention

[0023] This invention provides a hydrogenation catalyst and its preparation method, a method for the hydrogenation of aromatic compounds to synthesize alicyclic compounds. Using specially treated alumina with specific surface area, pore volume, and pore size as a support, a supported Ru-Rh bimetallic catalyst with highly uniform dispersion of active components is prepared by a stepwise loading method of Ru→Rh→Ru. This catalyst can catalyze the highly active and selective hydrogenation of various aromatic compounds to the corresponding alicyclic compounds at relatively low reaction temperatures and pressures. Furthermore, this catalyst has an extremely wide applicability range to process conditions such as reaction temperature and pressure; therefore, for different hydrogenation substrates, key stereoisomer indicators in the product can be effectively controlled simply by adjusting certain process parameters.

[0024] To achieve the above objectives, the present invention adopts the following technical solution:

[0025] In a first aspect, the present invention provides a hydrogenation catalyst, the catalyst comprising a support and an active component attached to the support. Based on 100% of the support mass, the content of metallic Ru is 0.05% to 30%, preferably 0.5% to 10%; the content of metallic Rh is 0.0001% to 1%, preferably 0.001% to 0.5%.

[0026] Preferably, the mass ratio of metal Ru:Rh in the catalyst is 10 to 1000:1, more preferably 50 to 100:1.

[0027] Preferably, the catalyst support is modified alumina.

[0028] Preferably, the specific surface area of ​​the modified alumina of the present invention is 10-200 m². 2 / g, preferably 20-100m 2 / g.

[0029] Preferably, the pore volume of the modified alumina of the present invention is 0.05–5 cm³. 3 / g, preferably 0.1~1cm 3 / g.

[0030] Preferably, the modified alumina of the present invention has an average pore size of 10-1000 nm, more preferably 20-100 nm.

[0031] Preferably, in the modified alumina carrier of the present invention, the mass percentage content of Li is 0.001% to 10%, more preferably 0.05% to 1%.

[0032] Secondly, the present invention also provides a method for preparing a modified alumina support, comprising the following steps:

[0033] (1) Add alumina powder to the lithium salt aqueous solution, stir evenly, impregnate, dry, and cool to room temperature;

[0034] (2) Add the product from step (1) to hexamethyldisilazane, stir evenly, let stand, and calcine.

[0035] The alumina raw powder of the present invention is selected from one or more of γ-Al2O3, η-Al2O3, δ-Al2O3, θ-Al2O3, k-Al2O3, and α-Al2O3 according to crystal form classification, with δ-Al2O3 and / or θ-Al2O3 being preferred.

[0036] The alumina powder of the present invention has a purity of ≥99.9%, preferably ≥99.95%.

[0037] The specific surface area of ​​the alumina raw powder described in this invention is 50-1000 m². 2 / g, preferably 80-300m 2 / g.

[0038] The alumina powder of the present invention has a pore volume of 0.05–10 cm³. 3 / g, preferably 0.2-3cm 3 / g.

[0039] The alumina powder of the present invention has an average pore size of 1-2000 nm, preferably 5-50 nm.

[0040] The total content of alkali metals other than Li in the alumina raw powder of the present invention is ≤100ppm, preferably ≤50ppm.

[0041] The lithium salt described in this invention is selected from one or more of LiNO3, HCOOLi·H2O, CH3COOLi, LiC2O4, Li2SO4, LiHSO4, LiOH·H2O, LiPF6, and LiH2PO4, with LiNO3 and / or LiH2PO4 being preferred.

[0042] Preferably, the mass ratio of the lithium salt to the alumina powder is 0.001 to 10:1.

[0043] Preferably, the mass ratio of hexamethyldisilazane to alumina powder is 0.001 to 5:1.

[0044] Preferably, the drying temperature in step (1) is 60-200℃, more preferably 80-150℃; the drying time is 2-20h, more preferably 4-6h.

[0045] Preferably, the roasting temperature in step (2) is 700-1200℃, more preferably 800-1000℃; and the roasting time is 1-20h, more preferably 3-10h.

[0046] The preparation method of the hydrogenation catalyst of the present invention includes the following steps:

[0047] (a) Mix the aqueous solution of Ru precursor with water-soluble organic amine, heat to T1, add support, mix, add alkali to adjust the pH of the system to pH1, filter, wash to neutral, dry, and the resulting catalyst intermediate is denoted as Z-1.

[0048] (b) Add ammonia and lithium hydroxide to the aqueous solution of Rh precursor to adjust the pH of the system to pH2, heat to T2, add Z-1 prepared in step (1), mix, add acid solution to adjust the pH of the system to pH3, filter, wash to neutral, dry, calcine, and the resulting catalyst intermediate is denoted as Z-2.

[0049] (c) Add trisulfonated triphenylphosphine to the Ru precursor aqueous solution, mix well, then add Z-2 prepared in step (b), mix, sonicate, let stand at room temperature, dry, and calcine.

[0050] Preferably, the Ru precursor in step (a) is one or more of Ru(OAc)3, (NH4)2RuCl6, RuCl3·3H2O, Ru2Cl2(CO)6, and Ru(NO)(NO3)3, with RuCl3·3H2O being the most preferred.

[0051] Preferably, the water-soluble organic amine in step (a) is one or more of ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N,N-dimethylethanolamine, N-ethyldiethanolamine, N,N-diethylethanolamine, isopropanolamine, diisopropanolamine, triisopropanolamine, diethylenetriamine, triethylenetetramine, and tetraethylenepentamine, and more preferably one or more of diethanolamine and diisopropanolamine.

[0052] Preferably, the mass ratio of Ru in the water-soluble organic amine / Ru precursor in step (a) is 100:1 to 0.01:1, more preferably 10:1 to 0.1:1.

[0053] Preferably, the water / Ru precursor mass ratio in the Ru precursor aqueous solution in step (a) is 10000:1 to 100:1, more preferably 1000:1 to 200:1.

[0054] Preferably, the Ru / carrier mass percentage in the Ru precursor in step (a) is 0.05% to 30%, more preferably 0.5% to 10%.

[0055] Preferably, the temperature T1 in step (a) is 30–90°C, more preferably 40–70°C.

[0056] Preferably, the mixing time in step (a) is 10 to 1000 min, more preferably 30 to 200 min.

[0057] Preferably, the base in step (a) is one or more of LiOH·H2O, Li2CO3, ammonia, methylamine, dimethylamine, and trimethylamine, with LiOH·H2O being the most preferred.

[0058] Preferably, the pH1 in step (a) is 7 to 12, more preferably 8 to 10.

[0059] Preferably, the drying temperature in step (a) is 60–150°C, more preferably 80–120°C.

[0060] Preferably, the drying time in step (a) is 1 to 100 hours, more preferably 5 to 50 hours.

[0061] Preferably, the Rh precursor in step (b) is one or more of RhCl3·3H2O, Rh(NO3)3, (NH4)3RhCl6, H3RhCl6, and Rh2(SO4)3, with RhCl3·3H2O and / or Rh(NO3)3 being more preferred.

[0062] Preferably, the water / Rh precursor mass ratio in the Rh precursor aqueous solution in step (b) is 10000:1 to 200:1, more preferably 2000:1 to 500:1.

[0063] Preferably, the mass percentage of Rh / Z-1 in the Rh precursor in step (b) is 0.0001%-1%, more preferably 0.001%-0.5%.

[0064] Preferably, the mass percentage concentration of ammonia in the ammonia water in step (b) is 5-30%, more preferably 10-20%.

[0065] Preferably, the amount of ammonia added in step (b), based on the mass ratio of ammonia to Rh in the Rh precursor, is 100:1 to 0.1:1, and more preferably 10:1 to 1:1.

[0066] Preferably, the pH value (pH2) in step (b) is 11 to 14, more preferably 12 to 13.

[0067] Preferably, the temperature T2 in step (b) is 30–80°C, more preferably 40–60°C.

[0068] Preferably, the mixing time in step (b) is 10 to 500 min, more preferably 30 to 200 min.

[0069] Preferably, the acid in step (b) is one or more of hydrochloric acid, sulfuric acid, nitric acid, and sulfurous acid, with hydrochloric acid being the most preferred.

[0070] Preferably, the mass percentage concentration of the acid solution in step (b) is 1-50%, more preferably 5-20%.

[0071] Preferably, the pH3 in step (b) is 5 to 9, more preferably 6 to 8.

[0072] Preferably, in step (b), the drying temperature is 80–120°C and the drying time is 1–10 h.

[0073] Preferably, the calcination temperature in step (b) is 300–600°C, more preferably 350–450°C.

[0074] Preferably, the roasting time in step (b) is 1 to 20 hours, more preferably 3 to 10 hours.

[0075] Preferably, the Ru precursor in step (c) is one or more of Ru(OAc)3, (NH4)2RuCl6, RuCl3·3H2O, Ru2Cl2(CO)6, and Ru(NO)(NO3)3, with RuNO(NO3)3 being the most preferred.

[0076] Preferably, the Ru / Z-2 mass percentage in the Ru precursor in step (c) is 0.05%-30%, more preferably 0.5%-10%.

[0077] Preferably, the water / Ru precursor mass ratio in the Ru precursor aqueous solution in step (c) is 500:1 to 5:1, more preferably 50:1 to 10:1.

[0078] Preferably, the mass ratio of trisulfonated triphenylphosphine / Ru precursor in step (c) is 20:1 to 0.1:1, more preferably 10:1 to 0.5:1.

[0079] Preferably, the drying temperature in step (c) is 60–150°C and the drying time is 1–20 h.

[0080] Preferably, the calcination temperature in step (c) is 300–600°C, more preferably 350–450°C.

[0081] Preferably, the roasting time in step (c) is 1 to 12 hours, more preferably 2 to 8 hours.

[0082] The present invention also provides a method for synthesizing alicyclic compounds by catalytic hydrogenation of aromatic compounds using the above-mentioned catalyst, comprising the following steps: controlling the reaction of a system containing a catalyst, an aromatic compound, a solvent and high-pressure hydrogen at a certain temperature and pressure for a period of time until the system hardly absorbs hydrogen, cooling, filtering, and obtaining a reaction mother liquor.

[0083] The aromatic compounds described in this invention include aromatic hydrocarbons, phenols, aromatic amines, and other types of aromatic compounds.

[0084] The aromatic hydrocarbons described in this invention are selected from one or more aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, trimethylbenzene, cumene, and biphenyl.

[0085] The phenols described in this invention are selected from one or more phenolic compounds such as phenol, p-cresol, o- / p-tert-butylphenol, catechol, resorcinol, hydroquinone, 2,6-di-tert-butylphenol, and bisphenol A.

[0086] The aromatic amines described in this invention are selected from one or more of the following aromatic amines: aniline, 4-methylaniline, 4-tert-butylaniline, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, m-phenylenediamine, p-phenylenediamine, 2,4-diaminotoluene, and 2,6-diaminotoluene.

[0087] The reaction temperature for the catalytic hydrogenation of aromatic compounds according to the present invention is 30–300°C, preferably 50–240°C; the reaction pressure is 1–20 MPa, preferably 2–15 MPa. The amount of catalyst used is 0.0005–0.2 times the mass of the substrate for the hydrogenation reaction, preferably 0.005–0.1 times.

[0088] Preferably, the solvent for hydrogenating the aromatic compound is selected from alcohol solvents such as methanol, ethanol, n-propanol, isopropanol, n-butanol, and cyclohexanol; ether solvents such as tetrahydrofuran and dioxane; cycloalkanes such as cyclohexane, methylcyclohexane, 1,2-dimethylcyclohexane, 1,3-dimethylcyclohexane, 1,4-dimethylcyclohexane, and decahydronaphthalene; and ethylenediamine, diethylamine, triethylamine, hexamethylenediamine, cyclohexylamine, 1,2-cyclohexanediamine, and 1... The solvent is one or more of the following amine solvents: 3-cyclohexanediamine, 1,4-cyclohexanediamine, 4,4'-diaminodicyclohexylmethane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, 1,3-cyclohexanedimethylamine, 1,4-cyclohexanedimethylamine, 4-methyl-1,3-cyclohexanediamine, and 2-methyl-1,3-cyclohexanediamine, preferably one or more of methylcyclohexane, tetrahydrofuran, ethanol, and cyclohexylamine.

[0089] Preferably, the mass ratio of the solvent to the aromatic compound is 0 to 100:1, more preferably 0.1 to 10:1.

[0090] Preferably, the reactor is a high-pressure autoclave hydrogenation reactor.

[0091] The beneficial effects of this invention are as follows:

[0092] (1) After modification with lithium salt and hexamethyldisilazane and high-temperature calcination, the surface acidity of the alumina support is eliminated. The catalyst prepared from this support can effectively inhibit the hydrogenolysis of aromatic compounds such as aromatic hydrocarbons, phenols and aromatic amines, and obtain the corresponding alicyclic compound products with high selectivity. In addition, the stability of the alumina support after modification and high-temperature treatment is greatly improved. During the catalyst preparation process, it can still maintain its macroscopic and microscopic structure and performance well even in aqueous media with strong acidity, alkalinity and high temperature.

[0093] (2) Noble metal Ru has a strong ability to adsorb and activate aromatic rings, but its ability to adsorb and activate hydrogen is relatively weak. High temperature and high pressure are often required to make up for its lack of activity. Introducing Rh, which has a strong ability to adsorb and activate hydrogen, into the catalyst can effectively make up for the lack of adsorption and activation ability of Ru to hydrogen. The two produce a synergistic effect and greatly improve the catalyst activity.

[0094] (3) In the first step of catalyst preparation, water-soluble organic amines such as ethanolamine and isopropanolamine are introduced, which can make Ru highly stable dispersed on the support surface and effectively inhibit the aggregation and growth of Ru crystal nuclei. In the second step, the amphoteric properties of Rh hydroxide are utilized to generate Rh anions under high pH conditions. These anions are more likely to penetrate into the internal pores of the support and adsorb on the inner surface of the support. Then, through acid neutralization, the Rh anions are converted into rhodium hydroxide precipitate and anchored on the inner surface of the support, thus achieving high dispersion of Rh. In the third step, triphenylphosphine trisulfonate is introduced, which forms a water-soluble complex with Ru, making it less likely for Ru to agglomerate during impregnation. Furthermore, due to its steric hindrance, the Ru loaded in this step can be adsorbed on the "vacancy" on the support surface that is not occupied by the active metal, thereby avoiding the aggregation of Ru loaded in the third step with the Ru and Rh loaded in the first two steps.

[0095] (4) For the hydrogenation of aromatic compounds containing two or more substituents on the benzene ring, low temperature is often more favorable for the formation of cis isomers, while high temperature is more favorable for the formation of trans isomers. Products with high trans-isotope content, such as 4-tert-butylcyclohexanol, 2-tert-butylcyclohexanol, 1,4-cyclohexanediamine, 1,4-cyclohexanedimethylamine, and 4,4'-diaminodicyclohexylmethane with high trans-isotope content, can often be obtained by increasing the hydrogenation temperature of the corresponding substrates. However, at high temperatures, hydrogenolysis side reactions of CO and CN are prone to occur, resulting in a decrease in product yield. Furthermore, high temperatures are prone to precious metal sintering and carbon deposition side reactions, causing a rapid decrease in catalyst activity and lifetime. Products with high cis-isotope content, such as 2-tert-butylcyclohexanol, 4-tert-butylcyclohexanol, 1,4-cyclohexanediol, 1,3-cyclohexanedimethylamine, and 4,4'-diaminodicyclohexylmethane with low trans-isotope content, can often be obtained by decreasing the hydrogenation temperature of the corresponding substrates. However, at low temperatures, the reaction rate is usually slower, and there are problems such as large catalyst dosage, high reaction pressure, long reaction time, and large solvent dosage. Furthermore, compounds with high trans-trans content such as 4,4'-diaminodicyclohexylmethane, high cis-trans content such as 1,3-cyclohexanedimethylamine, and high trans-trans content such as 1,4-cyclohexanedimethylamine often require additional isomerization reactions for synthesis. This not only increases process complexity but also makes the isomerization process prone to side reactions, leading to reduced product yields. The catalyst prepared in this invention maintains stable activity, selectivity, and lifetime over a wide temperature and pressure range. Therefore, while catalyzing the highly active and selective hydrogenation of various aromatic compounds, key isomer parameters in the product can be effectively controlled by adjusting process parameters such as reaction temperature. Detailed Implementation

[0096] The embodiments of the present invention are described in detail below. The specific embodiments described below are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0097] Gas chromatograph: Agilent 7890B, FID detector, DB-5 capillary column (30m x 250μm x 0.25μm), injection port 280℃, detector 300℃; temperature program: initial temperature 50℃, hold for 2 min, increase to 80℃ at 5℃ / min, then increase to 300℃ at 15℃ / min, hold for 15 min. Quantitative analysis was performed using the external standard method to calculate the conversion rate of the raw material and the yield of the product. The content of different stereoisomers in the product was calculated using the peak area normalization method: the content of a certain stereoisomer in the product = peak area of ​​that stereoisomer / sum of peak areas of all stereoisomers * 100%.

[0098] The grades and sources of various raw materials are shown in Table 1.

[0099] Table 1

[0100]

[0101]

[0102] Unless otherwise specified, all other ingredients are commercially available.

[0103] The relevant information about alumina carriers is shown in Table 2 below:

[0104] Table 2

[0105]

[0106]

[0107] (I) Catalyst Preparation Examples

[0108] Carrier modification example 1:

[0109] (1) Weigh 100g LiNO3, add 300g water to dissolve it, then add 100g δ-Al2O3 powder, stir evenly, soak at room temperature for 12h, dry at 120℃ for 5h, cool to room temperature, and use later.

[0110] (2) Add all the product obtained in step (1) to 50g of hexamethyldisilazane, stir and mix evenly, let stand at room temperature for 24h, then place it in a muffle furnace and calcine at 900℃ for 4h, cool to room temperature and use. The modified support obtained is denoted as G-Al2O3-1#.

[0111] Carrier modification example 2:

[0112] (1) Weigh 0.2g LiH2PO4, add 100g water to dissolve, then add 100g θ-Al2O3 powder, stir evenly, soak at room temperature for 12h, dry at 60℃ for 20h, cool to room temperature, and use later;

[0113] (2) Add all the product obtained in step (1) to 400g of hexamethyldisilazane, stir and mix evenly, let stand at room temperature for 24h, then place it in a muffle furnace and calcine at 700℃ for 8h, cool to room temperature and use. The modified support obtained is denoted as G-Al2O3-2#.

[0114] Carrier modification example 3:

[0115] (1) Weigh 5g LiOH·H2O, dissolve it in 200g water, add 100g δ-Al2O3 powder, stir evenly, soak at room temperature for 12h, dry at 90℃ for 10h, cool to room temperature, and use later;

[0116] (2) Add all the product obtained in step (1) to 0.2g of hexamethyldisilazane, stir and mix evenly, let stand at room temperature for 24h, then place it in a muffle furnace and calcine at 1100℃ for 2h, cool to room temperature and use. The modified support obtained is denoted as G-Al2O3-3#.

[0117] Carrier modification example 4:

[0118] (1) Weigh 800g HCOOLi·H2O, add 1000g water to dissolve, then add 100g γ-Al2O3 powder, stir evenly, soak at room temperature for 12h, dry at 150℃ for 3h, cool to room temperature, and use later.

[0119] (2) Add all the product obtained in step (1) to 1g of hexamethyldisilazane, stir and mix evenly, let stand at room temperature for 24h, then place it in a muffle furnace and calcine at 800℃ for 12h, cool to room temperature and use. The modified support obtained is denoted as G-Al2O3-4#.

[0120] Comparative Example 1 of Carrier Modification:

[0121] Weigh 100g of LiNO3, dissolve it in 300g of water, then add 100g of δ-Al2O3 powder, stir evenly, impregnate at room temperature for 12h, dry at 120℃ for 5h, then place it in a muffle furnace and calcine at 900℃ for 4h, cool to room temperature, and use it. The resulting modified support is denoted as D-Al2O3-1#.

[0122] Comparative Example 2 of Carrier Modification:

[0123] 50g of hexamethyldisilazane and 100g of δ-Al2O3 carrier powder were stirred and mixed evenly, and allowed to stand at room temperature for 24h. Then, the mixture was placed in a muffle furnace and calcined at 1000℃ for 3h. After cooling to room temperature, it was ready for use. The modified carrier obtained was designated as D-Al2O3-2#.

[0124] Catalyst preparation example 1:

[0125] (a) Weigh 6.157g RuCl3·3H2O, 1847.1g water and 15g diethanolamine, add them to a glass container equipped with stirring and heating, stir and mix evenly, heat to 50℃, then add 100g of the above modified alumina support G-Al2O3-1#, mix evenly, then gradually add 10% LiOH·H2O aqueous solution until the pH of the system is 9, filter, wash until neutral, dry the filter cake at 100℃ for 10h, and the obtained catalyst intermediate is denoted as Z-1;

[0126] (b) Weigh 0.256 g of RhCl3·3H2O and 255.9 g of water, add them to a glass container equipped with stirring and heating, stir and mix evenly, add 3.33 g of 15% ammonia water, and then gradually add 10% LiOH·H2O aqueous solution until the pH of the system is 12.5, raise the temperature to 60°C, maintain the temperature and stir for 120 min, then add 100 g of Z-1 prepared in step (a), mix evenly, gradually add 10% hydrochloric acid solution until the pH of the system is 7.5, filter, wash until neutral, dry the filter cake at 110°C for 6 h, then place it in a muffle furnace and calcine at 400°C for 5 h, cool to room temperature, and the obtained catalyst intermediate is denoted as Z-2;

[0127] (c) Weigh 6.275g RuNO(NO3)3 and 125.4g water, add them to a glass container equipped with stirring and heating, add 31.373g trisulfonated triphenylphosphine, mix well, add 100g catalyst intermediate Z-2 obtained in step (b), mix well, let stand at room temperature for 12h, dry at 80℃ for 8h, calcine at 400℃ for 8h, cool to room temperature, and the catalyst is obtained, denoted as C1.

[0128] Catalyst preparation example 2:

[0129] (a) Weigh 1.026g RuCl3·3H2O, 1026.2g water and 0.05g diisopropanolamine, add them to a glass container equipped with stirring and heating, stir and mix evenly, heat to 90℃, then add 100g of the above modified alumina support G-Al2O3-2#, mix evenly, then gradually add 20% ammonia solution until the pH of the system is 9, filter, wash until neutral, dry the filter cake at 100℃ for 10h, and the obtained catalyst intermediate is denoted as Z-1;

[0130] (b) Weigh 0.013g RhCl3·3H2O and 127.9g water, add them to a glass container with stirring and heating, stir and mix evenly, add 0.65g of 15% ammonia water, and then gradually add 10% LiOH·H2O aqueous solution until the pH of the system is 11. Raise the temperature to 30℃, maintain the temperature and stir for 120min, then add 100g of Z-1 prepared in step (a), mix evenly, gradually add 10% hydrochloric acid solution until the pH of the system is 5, filter, wash until neutral, dry the filter cake at 110℃ for 6h, then place it in a muffle furnace and calcine at 600℃ for 4h, cool to room temperature, and the obtained catalyst intermediate is denoted as Z-2;

[0131] (c) Weigh 25.099g RuNO(NO3)3 and 251g water, add them to a glass container equipped with stirring and heating, then add 25.099g trisulfonated triphenylphosphine, mix well, then add 100g of catalyst intermediate Z-2 obtained in step (b), mix well, let stand at room temperature for 12h, dry at 80℃ for 8h, then calcine at 300℃ for 6h, and cool to room temperature to obtain the catalyst, denoted as C2.

[0132] Catalyst preparation example 3:

[0133] (a) Weigh 34.636g of (NH4)2RuCl6, 1731.8g of water and 50g of diethylenetriamine, add them to a glass container equipped with stirring and heating, stir and mix evenly, heat to 30℃, then add 100g of the above modified alumina support G-Al2O3-3#, mix evenly, then gradually add 10% LiOH·H2O aqueous solution until the pH of the system is 11, filter, wash until neutral, dry the filter cake at 140℃ for 2h, and the obtained catalyst intermediate is denoted as Z-1;

[0134] (b) Weigh 1.797g of (NH4)3RhCl6 and 127.9g of water, add them to a glass container equipped with stirring and heating, stir and mix evenly, add 6.45g of 15% ammonia water, and then gradually add 10% LiOH·H2O aqueous solution until the pH of the system is 13, raise the temperature to 80℃, maintain the temperature and stir for 60min, then add 100g of catalyst intermediate Z-1 prepared in step (a), mix evenly, gradually add 20% sulfuric acid solution until the pH of the system is 9, filter, wash until neutral, dry the filter cake at 90℃ for 10h, then place it in a muffle furnace and calcine at 300℃ for 15h, cool to room temperature, and the obtained catalyst intermediate is denoted as Z-2;

[0135] (c) Weigh 0.205g RuCl3·3H2O and 102.6g water, add them to a glass container equipped with stirring and heating, add 4.104g trisulfonated triphenylphosphine, mix well, add 100g catalyst intermediate Z-2 obtained in step (b), mix well, let stand at room temperature for 6h, dry at 140℃ for 4h, calcine at 500℃ for 5h, cool to room temperature, and the catalyst is obtained, denoted as C3.

[0136] Catalyst preparation example 4:

[0137] (a) Weigh 0.063g RuNO(NO3)3, 313.7g water and 2g N-methyldiethanolamine, add them to a glass container equipped with stirring and heating, stir and mix evenly, heat to 70℃, then add 100g of the above modified alumina support G-Al2O3-4#, mix evenly, then gradually add 10% dimethylamine aqueous solution until the pH of the system is 8, filter, wash until neutral, dry the filter cake at 140℃ for 2h, and the obtained catalyst intermediate is denoted as Z-1;

[0138] (b) Weigh 0.036 g of (NH4)3RhCl6 and 359.4 g of water, add them to a glass container equipped with stirring and heating, stir and mix evenly, add 3.33 g of 15% ammonia water, and then gradually add 10% LiOH·H2O aqueous solution until the pH of the system is 12. Raise the temperature to 50°C and maintain the temperature at this temperature for 60 min. Then add 100 g of catalyst intermediate Z-1 prepared in step (a), mix evenly, and gradually add 20% sulfuric acid solution until the pH of the system is 8. Filter, wash until neutral, dry the filter cake at 90°C for 10 h, and then place it in a muffle furnace and calcine at 500°C for 12 h. Cool down to room temperature. The catalyst intermediate obtained is denoted as Z-2.

[0139] (c) Weigh 69.27g of (NH4)2RuCl6 and 692.7g of water, add them to a glass container equipped with stirring and heating, then add 34.64g of trisulfonated triphenylphosphine, mix well, then add 100g of catalyst intermediate Z-2 obtained in step (b), mix well, let stand at room temperature for 6h, dry at 140℃ for 4h, then calcine at 600℃ for 3h, and cool to room temperature to obtain the catalyst, denoted as C4.

[0140] Catalyst preparation comparative example 1:

[0141] Similar to Preparation Example 1, except that in step (a) the support G-Al2O3-1# is replaced with δ-Al2O3, and the resulting catalyst is denoted as D1. 。

[0142] Catalyst preparation Comparative Example 2:

[0143] Similar to Preparation Example 2, except that in step (a) the support G-Al2O3-1# is replaced with D-Al2O3-1#, and the resulting catalyst is denoted as D2. 。

[0144] Catalyst preparation comparative example 3:

[0145] Similar to Preparation Example 3, except that in step (a) the support G-Al2O3-1# is replaced with D-Al2O3-2#, and the resulting catalyst is denoted as D3. 。

[0146] Catalyst preparation comparative example 4:

[0147] (a) Weigh 6.157g RuCl3·3H2O, 1847.1g water and 15g diethanolamine, add them to a glass container equipped with stirring and heating, stir and mix evenly, heat to 50℃, then add 100g of the above modified alumina support G-Al2O3-1#, mix evenly, then gradually add 10% LiOH·H2O aqueous solution until the pH of the system is 9, filter, wash until neutral, dry the filter cake at 100℃ for 10h, and the obtained catalyst intermediate is denoted as DZ-1;

[0148] (b) Weigh 6.275g RuNO(NO3) and 125.4g water, add them to a glass container equipped with stirring and heating, add 31.373g trisulfonated triphenylphosphine, mix well, add 100g of catalyst intermediate DZ-1 obtained in step (a), mix well, let stand at room temperature for 12h, dry at 80℃ for 8h, calcine at 400℃ for 8h, cool to room temperature, and the catalyst is obtained, denoted as D4.

[0149] Catalyst preparation comparative example 5:

[0150] Weigh 0.256g RhCl3·3H2O and 255.9g water, add them to a glass container equipped with a stirrer and heater, stir and mix evenly, add 3.33g of 15% ammonia water, and then gradually add 10% LiOH·H2O aqueous solution until the pH of the system is 12.5. Raise the temperature to 60℃ and maintain this temperature while stirring for 120min. Then add 100g D-Al2O3-1# and mix evenly. Gradually add 10% hydrochloric acid solution until the pH of the system is 7. Filter, dry the filter cake at 110℃ for 6h, and then calcine it in a muffle furnace at 400℃ for 5h. Cool to room temperature. The obtained catalyst is denoted as D5.

[0151] (II) Examples of Hydrogenation of Aromatic Compounds

[0152] Example 1:

[0153] 400g of benzene and 2g of catalyst C1 were added to a 1L high-pressure reactor. The reactor was then fitted with gas and hydrogen gas at 1MPa for 3 purgings each. The hydrogenation reaction was carried out at a temperature of 100℃, a pressure of 4MPa, and a stirring speed of 800rpm. The hydrogen absorption rate was monitored using a hydrogen mass flow meter. After 150min, when the instantaneous hydrogen absorption rate dropped to below 10sccm, the hydrogen inlet valve was closed, the reactor was cooled, and the residual gas in the reactor was discharged. The reaction mother liquor was filtered out using a built-in filter, and external standard quantitative analysis was performed using gas chromatography. The results showed that the benzene conversion rate was 100% and the cyclohexane selectivity was 100%.

[0154] Example 2:

[0155] Similar to Example 1, except that the raw material was replaced with 400g of toluene, the catalyst was replaced with 4g of C2, the reaction temperature was 140℃, the pressure was 6MPa, and the reaction time was 120min, resulting in a toluene conversion rate of 100% and a methylcyclohexane selectivity of 100%.

[0156] Example 3:

[0157] Similar to Example 1, except that the raw material was replaced with 400g of p-xylene, the catalyst was replaced with 0.5g of C3, the reaction temperature was 180℃, the pressure was 8MPa, and the reaction time was 210min, resulting in a p-xylene conversion rate of 100% and a 1,4-dimethylcyclohexane selectivity of 100%.

[0158] Example 4:

[0159] Similar to Example 1, except that the raw material was replaced with 400g of ethylbenzene, the catalyst was replaced with 0.1g of C4, the reaction temperature was 120℃, the pressure was 5MPa, and the reaction time was 160min, resulting in an ethylbenzene conversion rate of 100% and an ethylcyclohexane selectivity of 100%.

[0160] Example 5:

[0161] Similar to Example 1, except that the raw material was replaced with 400g of 1,2,4-trimethylbenzene, the catalyst was replaced with 20g of C1, the reaction temperature was 230℃, the pressure was 12MPa, and the reaction time was 110min, resulting in a 100% conversion rate of 1,2,4-trimethylbenzene and a 100% selectivity for 1,2,4-trimethylcyclohexane.

[0162] Example 6:

[0163] Similar to Example 5, except that the raw material was replaced with 400g of 1,3,5-trimethylbenzene, and the reaction time was 150min, resulting in a 100% conversion rate of 1,3,5-trimethylbenzene and a 100% selectivity for 1,3,5-trimethylcyclohexane.

[0164] 1,3,5-Trimethylcyclohexane was prepared using the same hydrogenation reaction procedure as in Example 6, and a catalyst reuse test was conducted. The reaction results are shown in Table 3.

[0165] Table 3

[0166]

[0167]

[0168] Example 7:

[0169] Similar to Example 1, except that the raw material was replaced with 400g of cumene, the reaction temperature was 180℃, the pressure was 5MPa, and the reaction time was 140min, resulting in a 100% conversion rate of trimethylbenzene and a 100% selectivity for isopropylcyclohexane.

[0170] Example 8:

[0171] Similar to Example 1, except that the raw material was replaced with 400g of biphenyl, the catalyst was 40g of C1, the reaction temperature was 80℃, the pressure was 3MPa, and the reaction time was 210min, resulting in a biphenyl conversion rate of 100% and a bicyclohexane selectivity of 100%.

[0172] Comparative Example 1:

[0173] Similar to Example 3, except that the catalyst was replaced with 20g D4 and the reaction time was 300min, resulting in a p-xylene conversion rate of 98.6% and a 1,4-dimethylcyclohexane selectivity of 99.0%.

[0174] Comparative Example 2:

[0175] Similar to Example 5, except that the catalyst was replaced with 10g D5 and the reaction time was 330min, resulting in a 97.6% conversion of 1,2,4-trimethylbenzene and a 98.9% selectivity for 1,2,4-trimethylcyclohexane.

[0176] Comparative Example 3:

[0177] Similar to Example 5, except that the catalyst was replaced with 40g of commercially available 5% Ru-1% Rh / Al2O3 catalyst, and the reaction time was 280min, resulting in a 96.8% conversion of 1,2,4-trimethylbenzene and a 96.3% selectivity for 1,2,4-trimethylcyclohexane.

[0178] Example 9:

[0179] 300g phenol, 600g ethanol, and 3g catalyst C1 were added to a 1L high-pressure reactor. The reactor was then topped with gas, and the mixture was purged three times each with 1MPa nitrogen and hydrogen gas to carry out the hydrogenation reaction. The reaction temperature was 60℃, the pressure was 3MPa, and the stirring speed was 800rpm. The hydrogen absorption rate was monitored using a hydrogen mass flow meter. After 180min, when the instantaneous hydrogen absorption rate dropped to below 10sccm, the hydrogen inlet valve was closed, the reactor was cooled, and the residual gas in the reactor was discharged. The reaction mother liquor was filtered out using a built-in filter, and the external standard was used for quantitative analysis by gas chromatography. The results showed that the phenol conversion rate was 100% and the cyclohexanol selectivity was 99.9%.

[0180] Example 10:

[0181] Similar to Example 9, except that the raw material was replaced with 300g of p-cresol, the reaction time was 120min, the p-cresol conversion rate was 100%, the p-methylcyclohexanol selectivity was 99.9%, and the cis-isocyanate content in the product was 82%.

[0182] Example 11:

[0183] Similar to Example 9, except that the raw material was replaced with 300g of o-tert-butylphenol, the reaction temperature was 80°C, the pressure was 6MPa, and the reaction time was 90min, resulting in a 100% conversion rate of o-tert-butylphenol, a 99.9% selectivity of o-tert-butylcyclohexanol, and a cis-isocyanate content of 96% in the product.

[0184] Example 12:

[0185] Similar to Example 9, except that the raw material was replaced with 300g of p-tert-butylphenol, the reaction temperature was 60°C, the pressure was 8MPa, and the reaction time was 120min, resulting in a p-tert-butylphenol conversion rate of 100%, a p-tert-butylcyclohexanol selectivity of 99.9%, and a cis-isocyanate content of 84% in the product.

[0186] Example 13:

[0187] Similar to Example 9, except that the raw material was replaced with 300g hydroquinone, the catalyst was replaced with 1g C3, the reaction time was 210min, and the hydroquinone conversion rate was 100%, the 1,4-cyclohexanediol selectivity was 99.9%, and the cis-isocyanate content in the product was 78%.

[0188] Example 14:

[0189] Similar to Example 9, except that the raw material was replaced with 300g of 2,6-di-tert-butylphenol, the catalyst was replaced with 8g of C4, the reaction temperature was 180℃, the pressure was 5MPa, and the reaction time was 60min, resulting in a 100% conversion rate of 2,6-di-tert-butylphenol and a 99.9% selectivity for 2,6-di-tert-butylcyclohexanol.

[0190] Example 15:

[0191] Similar to Example 9, except that the raw material was replaced with 300g of bisphenol A, the reaction time was 150min, the conversion rate of bisphenol A was 100%, the selectivity of hydrogenated bisphenol A was 99.9%, and the content of trans-trans isomers in the product was 38%.

[0192] Example 16:

[0193] Similar to Example 15, except that the reaction temperature was 180°C, the pressure was 8 MPa, and the reaction time was 90 min, the conversion rate of bisphenol A was 100%, the selectivity of hydrogenated bisphenol A was 99.8%, and the content of trans-trans isomers in the product was 54%.

[0194] Hydrogenated bisphenol A was prepared using the same hydrogenation reaction steps as in Example 16, and a catalyst reuse test was conducted. The reaction results are shown in Table 4.

[0195] Table 4

[0196]

[0197]

[0198] Comparative Example 4:

[0199] Similar to Example 9, except that the catalyst was replaced with 3g D1, the reaction time was 240min, and the phenol conversion rate was 95.3% and the cyclohexanol selectivity was 94.5%.

[0200] Comparative Example 5:

[0201] Same as Example 12, except that the catalyst was replaced with 6g D4, the reaction time was 300min, and the conversion rate of p-tert-butylphenol was 96.5%, the selectivity of p-tert-butylcyclohexanol was 97.9%, and the cis-isocyanate content in the product was 76%.

[0202] Comparative Example 6:

[0203] Similar to Example 16, except that the catalyst was 6g of commercially available 5% Ru / Al2O3 catalyst, the reaction time was 270min, the conversion rate of bisphenol A was 94.2%, the selectivity of hydrogenated bisphenol A was 91.2%, and the content of trans-trans isomers in the product was 49%.

[0204] Example 17:

[0205] 300g aniline, 300g tetrahydrofuran, and 3g catalyst C1 were added to a 1L high-pressure reactor. The reactor was then topped with gas, and the reactor was purged three times each with 1MPa nitrogen and hydrogen gas to carry out the hydrogenation reaction. The reaction temperature was 80℃, the pressure was 5MPa, and the stirring speed was 800rpm. The hydrogen absorption rate was monitored using a hydrogen mass flow meter. After 120min of reaction, the instantaneous hydrogen absorption rate dropped to below 10sccm. The hydrogen inlet valve was then closed, the reactor was cooled, and the residual gas in the reactor was discharged. The reaction mother liquor was filtered out using a built-in filter, and the external standard was used for quantitative analysis by gas chromatography. The results showed that the aniline conversion rate was 100% and the cyclohexylamine selectivity was 99.8%.

[0206] Example 18:

[0207] Similar to Example 17, except that the raw material was replaced with 300g of 4-methylaniline, the reaction temperature was 70℃, the pressure was 6MPa, and the reaction time was 140min, resulting in a 4-methylaniline conversion rate of 99.5%, a 4-methylcyclohexylamine selectivity of 99.8%, and a trans isomer content of 56% in the product.

[0208] Example 19:

[0209] Similar to Example 18, except that the reaction temperature was 190°C, the pressure was 7 MPa, and the reaction time was 80 min, the conversion rate of 4-methylaniline was 100%, the selectivity of 4-methylcyclohexylamine was 99.6%, and the content of trans isomer in the product was 79%.

[0210] Example 20:

[0211] Similar to Example 17, except that the raw material was replaced with 300g of p-phenylenediamine, the catalyst was replaced with 4g of C2, the reaction temperature was 120℃, the pressure was 4MPa, and the reaction time was 180min. The p-phenylenediamine conversion rate was 99.5%, the 1,4-cyclohexanediamine selectivity was 99.8%, and the trans isomer content in the product reached 49%.

[0212] Example 21:

[0213] Similar to Example 20, except that the reaction temperature was 200°C, the pressure was 8 MPa, and the reaction time was 70 min, the conversion rate of p-phenylenediamine was 99.8%, the selectivity of 1,4-cyclohexanediamine was 99.7%, and the content of trans isomer in the product was 81%.

[0214] Example 22:

[0215] Similar to Example 17, except that the raw material was replaced with 300g of 4,4'-diaminodiphenylmethane, the catalyst was replaced with 6g of C3, the reaction temperature was 100℃, the pressure was 5MPa, and the reaction time was 170min. The conversion rate of 4,4'-diaminodiphenylmethane was 99.3%, the selectivity of 4,4'-diaminodicyclohexylmethane was 99.5%, and the content of trans-trans isomers in the product was 11%.

[0216] 4,4'-Diaminodicyclohexylmethane was prepared using the same hydrogenation reaction procedure as in Example 22, and a catalyst reuse test was conducted. The reaction results are shown in Table 5.

[0217] Table 5

[0218]

[0219] Example 23:

[0220] Similar to Example 22, except that the reaction temperature was 190°C, the pressure was 7 MPa, and the reaction time was 70 min, resulting in a 99.9% conversion rate of 4,4'-diaminodiphenylmethane, a 99.4% selectivity for 4,4'-diaminodicyclohexylmethane, and a 53% content of trans-trans isomers in the product.

[0221] Example 24:

[0222] Similar to Example 17, except that the raw material was replaced with 300g of 3,3'-dimethyl-4,4'-diaminodiphenylmethane, the catalyst was replaced with 2g of catalyst C4, the reaction temperature was 110℃, the pressure was 4MPa, and the reaction time was 220min. The resulting product had a 3,3'-dimethyl-4,4'-diaminodiphenylmethane conversion rate of 99.5%, a 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane selectivity of 99.8%, and a 3e,4e,3'e,4'a-3,3'-dimethyl-4,4'-diaminodicyclohexylmethane content of 12%.

[0223] Example 25:

[0224] Similar to Example 17, except that the raw material was replaced with 300g of m-phenylenediamine, the reaction temperature was 50°C, the pressure was 9MPa, and the reaction time was 180min. The m-phenylenediamine conversion rate was 99.7%, the selectivity of 1,3-cyclohexanedimethylamine was 99.9%, and the cis-isocyanate content in the product was 82%.

[0225] 1,3-cyclohexanedimethylamine was prepared using the same hydrogenation reaction procedure as in Example 25, and a catalyst reuse test was conducted. The reaction results are shown in Table 6.

[0226] Table 4

[0227]

[0228] Example 26:

[0229] Similar to Example 25, except that the raw material was replaced with 300g of p-phenylenediamine, the reaction time was 160min, the p-phenylenediamine conversion rate was 99.4%, the selectivity of 1,4-cyclohexanedimethylamine was 99.6%, and the trans content in the product was 56%.

[0230] Example 27:

[0231] Similar to Example 26, except that the reaction temperature was 160°C and the reaction time was 80 min, the conversion rate of p-phenylenediamine was 100%, the selectivity of 1,4-cyclohexanedimethylamine was 99.4%, and the trans content in the product was 82%.

[0232] Example 28:

[0233] Similar to Example 17, except that the raw material was replaced with 300g of 2,4-diaminotoluene, the reaction temperature was 150℃, the pressure was 6MPa, and the reaction time was 180min, resulting in a 99.1% conversion rate of 2,4-diaminotoluene and a 99.2% selectivity for 4-methyl-1,3-cyclohexanediamine.

[0234] Example 29:

[0235] Similar to Example 28, except that the raw material was replaced with 300g of 2,6-diaminotoluene, and the reaction was carried out for 170min, resulting in a 99.4% conversion rate of 2,6-diaminotoluene and a 99.6% selectivity for 2-methyl-1,3-cyclohexanediamine.

[0236] Comparative Example 7:

[0237] Similar to Example 20, except that the catalyst was replaced with 6g D1, the reaction time was 210min, and the conversion rate of p-phenylenediamine was 95.7%, the selectivity of 1,4-cyclohexanediamine was 89.2%, and the content of trans isomer in the product was 39%.

[0238] Comparative Example 8:

[0239] Similar to Example 21, except that the catalyst was replaced with 6g D2, the reaction time was 80min, and the conversion rate of p-phenylenediamine was 98.7%, the selectivity of 1,4-cyclohexanediamine was 75.5%, and the content of trans isomer in the product was 75%.

[0240] Comparative Example 9:

[0241] Same as Example 22, except that the catalyst was replaced with 6g of catalyst D4, the reaction time was 210min, and the conversion rate of 4,4'-diaminodiphenylmethane was 94.6%, the selectivity of 4,4'-diaminodicyclohexylmethane was 92.5%, and the content of trans-trans isomers in the product was 25%.

[0242] Comparative Example 10:

[0243] Similar to Example 25, except that the catalyst was replaced with 6g D5, the reaction time was 300min, and the conversion rate of m-phenylenediamine was 92.8%, the selectivity of 1,3-cyclohexanedimethylamine was 97.2%, and the content of cis isomer in the product was 71%.

[0244] Comparative Example 11:

[0245] Same as Example 28, except that the catalyst was replaced with 6g of commercially available 3% Rh / Al2O3, the reaction time was 260min, and the conversion rate of 2,4-diaminotoluene was 93.0%, and the selectivity of 4-methyl-1,3-cyclohexanediamine was 81.5%.

[0246] As can be seen from the data in the above embodiments, the catalyst prepared by the present invention has strong versatility, a wide range of applicable processes, excellent activity, selectivity and lifetime for the hydrogenation of various aromatic compounds, and can achieve the control of key isomer indicators in the product, greatly expanding the application performance of the product.

Claims

1. A hydrogenation catalyst, comprising a carrier and an active component attached to the carrier, wherein the content of metal Ru is 0.05% to 30%, preferably 0.5% to 10%, and the content of metal Rh is 0.0001% to 1%, preferably 0.001% to 0.5%, based on 100% of the mass of the carrier; the mass ratio of metal Ru:Rh in the catalyst is 10 to 1000:1, preferably 50 to 100:1; and the carrier of the catalyst is modified alumina.

2. The hydrogenation catalyst according to claim 1, characterized by The specific surface area of the modified alumina is 10 to 200 m 2 / g, preferably 20 to 100 m 2 / g; the pore volume is 0.05 to 5 cm 3 / g, preferably 0.1 to 1 cm 3 / g; the average pore diameter is 10 to 1000 nm, preferably 20 to 100 nm; and / or the mass percentage of Li in the modified alumina support is 0.001% to 10%, preferably 0.05% to 1%.

3. The hydrogenation catalyst according to claim 2, characterized in that, The method for preparing the modified alumina carrier comprises the following steps: (1) adding alumina raw powder to an aqueous lithium salt solution, stirring uniformly, impregnating, drying, and cooling to room temperature; (2) adding the product of step (1) to hexamethyldisilazane, stirring uniformly, standing, and calcining.

4. The hydrogenation catalyst according to claim 3, characterized by The mass ratio of the lithium salt to the alumina raw powder is 0.001 to 10:1; and / or the mass ratio of the hexamethyldisilazane to the alumina raw powder is 0.001 to 5:

1.

5. A method for preparing the hydrogenation catalyst of any one of claims 1 to 4, comprising the following steps: (a) mixing an aqueous Ru precursor solution with a water-soluble organic amine, heating to 30 to 90°C, preferably 40 to 70°C, adding the carrier thereto, mixing, adding alkali to adjust the pH of the system to 7 to 12, preferably 8 to 10, filtering, washing to neutral, and drying to obtain a catalyst intermediate, which is denoted as Z-1; (b) adding ammonia water and lithium hydroxide to an aqueous Rh precursor solution to adjust the pH of the system to 11 to 14, preferably 12 to 13, heating to 30 to 80°C, preferably 40 to 60°C, adding Z-1 prepared in step (1), mixing, adding an acid solution to adjust the pH of the system to 5 to 9, preferably 6 to 8, filtering, washing to neutral, drying, and calcining to obtain a catalyst intermediate, which is denoted as Z-2; (c) adding triphosphine sulfonate to an aqueous Ru precursor solution, mixing uniformly, adding Z-2 prepared in step (b), mixing, ultrasonicating, standing at room temperature, drying, and calcining.

6. The method of claim 5, wherein, The Ru precursor is one or more of Ru(OAc)3, (NH4)2RuCl6, RuCl3·3H2O, Ru2Cl2(CO)6, and Ru(NO)(NO3)3; and the Rh precursor is one or more of RhCl3·3H2O, Rh(NO3)3, (NH4)3RhCl6, H3RhCl6, and Rh2(SO4)3.

7. The method of claim 5, wherein, The mass ratio of triphosphine sulfonate to the Ru precursor in step (c) is 20:1 to 0.1:1, preferably 10:1 to 0.5:

1.

8. A method for synthesizing an alicyclic compound by hydrogenation of an aromatic compound, comprising the step of reacting a system containing the hydrogenation catalyst of any one of claims 1 to 4 or the catalyst prepared by the method of any one of claims 5 to 7, an aromatic compound, a solvent, and high-pressure hydrogen gas at a certain temperature and pressure.

9. The method for synthesizing an alicyclic compound by hydrogenation of an aromatic compound according to claim 8, wherein The aromatic hydrocarbon is selected from one or more of benzene, toluene, xylene, ethylbenzene, mesitylene, cumene, biphenyl; the phenol is selected from one or more of phenol, p-cresol, o / p-tert-butylphenol, o-dihydroxybenzene, m-dihydroxybenzene, p-dihydroxybenzene, 2,6-di-tert-butylphenol, bisphenol A; the aromatic amine is selected from one or more of aniline, 4-methylaniline, 4-tert-butylaniline, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, m-toluenediamine, p-toluenediamine, 2,4-diaminotoluene, 2,6-diaminotoluene.

10. The method of synthesizing an alicyclic compound by hydrogenation of an aromatic compound according to claim 8 or 9, characterized by, The reaction temperature for the hydrogenation is 30-300°C, preferably 50-240°C; the reaction pressure is 1-20 MPa, preferably 2-15 MPa.

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