Preparation method of bio-based naphthenic diamine and bio-based naphthenic diamine

Abstract

The invention discloses a preparation method of bio-based naphthenic diamine and bio-based naphthenic diamine, and belongs to the technical field of fine chemical synthesis. The preparation method of the bio-based naphthenic diamine comprises the following steps: (1) mixing C10-C20 bio-based diene cycloolefin, a first catalyst and synthesis gas, and reacting to obtain a reaction system S1 containing a C12-C22 naphthenic dicarboxaldehyde intermediate; and (2) mixing the S1 with ammonia gas, a second catalyst and organic weak acid for reaction to obtain the C12-C22 bio-based naphthenic diamine. According to the preparation method disclosed by the invention, bio-based diene cycloolefin is taken as a starting raw material, and through selection of a catalyst and regulation and control of process conditions, side reactions are effectively inhibited, efficient series connection of hydroformylation and reductive ammoniation is realized, the production process is simplified, the yield and purity of the product are improved, and green preparation of naphthenic diamine is realized; the production cost is reduced, and the method has a good industrial application prospect.

Description

Technical Field

[0001] This invention relates to the technical field of fine chemical synthesis, and in particular to a method for preparing a bio-based cycloalkyl diamine and the bio-based cycloalkyl diamine. Background Technology

[0002] Cycloalkyl diamines are an important class of nitrogen-containing fine chemicals. Due to their unique alicyclic structure, they possess excellent temperature resistance, yellowing resistance, and reactivity, making them widely used in high-end fields such as epoxy resin curing agents, polyamide monomers, advanced corrosion inhibitors, and oilfield chemicals, resulting in strong market demand. Currently, the mainstream industrial route uses petroleum-based olefins as raw materials, achieving the preparation of cycloalkyl diamines through a two-step reaction of hydroformylation and reductive amination. However, this route has significant drawbacks.

[0003] First, the raw materials are heavily reliant on non-renewable petroleum resources. The scarcity of petroleum-based raw materials and the problem of high carbon footprint are becoming increasingly prominent. Developing synthetic routes containing renewable raw materials has become an urgent need for the industry.

[0004] Secondly, in the traditional process for preparing cycloalkanediamines from petroleum-based olefins, hydroformylation and reductive amination are often carried out in steps. The hydroformylation product, aldehyde, needs to be separated and purified before the reductive amination reaction can proceed. This process is cumbersome, requires significant equipment investment, and is energy-intensive. Furthermore, the separation process easily leads to aldehyde loss, reducing the overall product yield. Simultaneously, aldehydes and ammonia readily undergo condensation reactions during the reaction, generating imine polymers and aldehyde condensation byproducts. This results in a complex product composition, reduced purity, and increased difficulty in subsequent separation and purification, further increasing production costs and limiting the large-scale production and high-end applications of cycloalkanediamines.

[0005] In addition, in the existing hydroformylation-reduction ammoniation process, the catalysts are mostly precious metal systems, which have problems such as high cost, difficulty in recovery, and susceptibility to impurity poisoning. Moreover, the reaction conditions are harsh, making it difficult to achieve efficient conversion under mild conditions.

[0006] Limonene, as a bio-based monoterpene olefin with abundant reserves and wide sources, is mainly extracted from biomass such as citrus peel essential oil and turpentine oil. It has the advantages of being renewable, green and environmentally friendly, and low cost, making it an ideal raw material to replace petroleum-based olefins in the preparation of cycloalkyl diamines. However, there is currently no mature process to efficiently convert limonene into high-purity cycloalkyl diamines.

[0007] Related studies have shown that limonene can be converted into aldehyde intermediates through hydroformylation, and then converted into amine compounds through reductive ammoniation. However, existing technologies mostly focus on the preparation of monoamine products, and have problems such as poor reaction selectivity, serious side reactions, and low product purity. They cannot achieve the efficient preparation of high-purity cycloalkanediamines, nor can they effectively solve the condensation problem of aldehydes and ammonia, making it difficult to meet the purity requirements of cycloalkanediamines in high-end fields such as epoxy curing agents and polyamides.

[0008] Therefore, developing a method for preparing bio-based cycloalkyldiamines using renewable limonene as raw material, with a short process, few side reactions, and high product purity, is key to overcoming existing technological bottlenecks and promoting the green upgrading of the cycloalkyldiamine industry. Summary of the Invention

[0009] In view of this, the technical problem to be solved by the present invention is to provide a method for preparing bio-based cycloalkyl diamines and the bio-based cycloalkyl diamines themselves. The preparation method achieves the green and efficient preparation of high-purity, highly selective bio-based cycloalkyl diamines.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0011] This invention provides a method for preparing bio-based cycloalkyl diamines, comprising the following steps:

[0012] (1) C 10 -C 20 Bio-based diene cycloolefins, a first catalyst, and syngas are mixed and reacted to obtain C-containing... 12 -C 22 The reaction system S1 for the cycloalkanedicarboxaldehyde intermediate;

[0013] (2) S1 is mixed with ammonia, a second catalyst and a weak organic acid to react and obtain C. 12 -C 22 Bio-based cycloalkyl diamine;

[0014] Preferably, the synthesis gas includes carbon monoxide and hydrogen.

[0015] The preparation method described in this invention uses C 10 -C 20 Bio-based diene cycloolefins were used as starting materials, and the C was prepared by sequentially performing a hydroformylation reaction (step (1)) and a reductive amination reaction (step (2)). 12 -C 22 Bio-based cycloalkyl diamine.

[0016] The product C of step (1) 12 -C 22 The cycloalkanedialdehyde intermediate has a high yield (≥90%) and can be used as a raw material for the reductive amination reaction described in step (2) without the need for separation and purification.

[0017] The reductive amination reaction in step (2) causes the C 12 -C 22 Both aldehyde groups in the cycloalkanedialdehyde intermediate undergo reductive amination to convert to amino groups.

[0018] The hydroformylation and reductive amination reactions are carried out using suitable catalytic systems.

[0019] The first catalyst of the present invention can selectively catalyze the sequential hydroformylation of two carbon-carbon double bonds in the bio-based diene cycloolefin to generate a dialdehyde intermediate, and inhibit the dissociation of the monoaldehyde intermediate from the catalytic center.

[0020] Preferably, the first catalyst is selected from rhodium-based catalysts, cobalt-based catalysts, or mesoporous confined transition metal single-atom catalysts;

[0021] Preferably, the rhodium-based catalyst comprises a rhodium-based metal center and a bidentate phosphine ligand;

[0022] Preferably, the cobalt-based catalyst comprises a cobalt-based metal center and a phosphine-containing host ligand;

[0023] Preferably, the mesoporous confined transition metal single-atom catalyst comprises a support A and a transition metal single atom, wherein the transition metal single atom is supported on the surface of the support A and within the pores, and a phosphine ligand is grafted into the pores.

[0024] Preferably, the second catalyst consists of a support B and transition metal single atoms supported on its surface.

[0025] The C of this invention 10 -C 20 Bio-based diene cyclic olefins are unsaturated cyclic monomers synthesized using biomass as a carbon source, with the molecule containing at least two carbon-carbon double bonds and at least one double bond located within a ring.

[0026] In step (1) of the above preparation method, the cycloalkane dicarboxaldehyde intermediate exhibits good selectivity and a high yield (≥90%), which is mainly due to the combined effect of the selection of the catalytic system and the regulation of the reaction conditions.

[0027] (a) Selection of catalytic system

[0028] When the first catalyst is selected from the rhodium-based catalyst, the rhodium-based metal center and the bidentate phosphine ligand work together. The steric hindrance of the bidentate phosphine ligand can effectively promote the simultaneous coordination and insertion reaction of the two double bonds (inside and outside the ring) of the bio-based diene cycloolefin, suppress the selectivity of single and double bond reactions, reduce the isomerization side reaction of the bio-based diene cycloolefin, ensure that the yield of the cycloalkanedic aldehyde intermediate is ≥90%, and avoid the accumulation of monoaldehyde intermediates leading to the formation of subsequent monoamine products.

[0029] When the first catalyst is selected from cobalt-based catalysts, the cobalt-based metal center and the phosphine-containing main ligand work together to significantly improve the yield and selectivity of the cycloalkanedialdehyde intermediate. Furthermore, the cobalt-based catalyst is lower in cost and less sensitive to raw material impurities, allowing for the selection of a suitable system based on industrial cost requirements.

[0030] When the first catalyst is selected from a mesoporous confined transition metal single-atom catalyst, the pore confinement effect of the catalyst can further enhance the regioselectivity of the cycloalkane dicarboxaldehyde intermediate, and the catalyst has excellent catalytic activity and stability, with a TON of over 60,000.

[0031] (ii) Regulation of reaction conditions

[0032] The preparation method described in this invention employs a step-by-step temperature and pressure control method in step (1) to avoid the problem of double bond isomerism caused by excessively high temperature and pressure, and incomplete reaction caused by excessively low temperature and pressure.

[0033] By balancing the reactivity of the two double bonds in bio-based diene cycloalkenes under appropriate reaction conditions, we can avoid overreaction of the exocyclic double bonds and underreaction of the intracyclic double bonds, ensuring that the two double bonds are simultaneously converted into aldehyde groups. This controls the selectivity of the dialdehyde intermediate from the source and lays the foundation for the subsequent formation of diamines.

[0034] In step (2) of the above preparation method, the bio-based cycloalkyl diamine exhibits good selectivity (≥95%), which is mainly due to the combined effects of the selection of the catalytic system, the regulation of the reaction conditions, and the amount and method of ammonia injection.

[0035] (a) Selection of catalytic system

[0036] The active component of the second catalyst, a transition metal single atom (which has high activity and high selectivity), is used to efficiently promote the simultaneous hydrogenation and amination of the two aldehyde groups in the cycloalkanedicarboxaldehyde intermediate, thus avoiding the inhibition of the other aldehyde group reaction after the preferential amination of the single aldehyde group.

[0037] (ii) Regulation of reaction conditions

[0038] By controlling the reaction temperature and pressure to suppress the condensation of aldehyde groups and the occurrence of excessive hydrogenation side reactions, the efficient conversion of the two aldehyde groups into amino groups (-CH2NH2) is ensured, thereby improving the diamine selectivity.

[0039] (III) Control of Ammonia Usage and Inlet Method

[0040] A certain amount of ammonia gas is added to the reaction system S1 slowly and continuously to avoid the aldehyde condensation side reaction caused by excessive ammonia, while ensuring that both aldehyde groups can fully contact ammonia to prevent the other aldehyde group from remaining unreacted after the ammonia of one aldehyde group.

[0041] In the preparation method described in this invention, the C 10 -C 20 Bio-based diene cycloalkenes are selected from monoterpenes, diterpenes, or their modified dimers among terpenoid compounds;

[0042] The monoterpenes include, but are not limited to, limonene, α-terpinene, γ-terpinene, terpinene, and phellandrene.

[0043] The diterpenes include, but are not limited to, pinene, isopyridene, etc.

[0044] The modified dimer includes, but is not limited to, α-pinene dimer. Preferably, the C... 10 -C 20 The bio-based diene cycloolefin is selected from limonene, α-pinene dimer, or coniferene. In some specific embodiments of the present invention, limonene is preferred.

[0045] Preferably, the purity of the limonene is ≥98%.

[0046] The mixed gas contains an excess of carbon monoxide and a portion of hydrogen, with the remaining hydrogen being used for the reductive amination reaction in step (2).

[0047] Preferably, the volume ratio of carbon monoxide to hydrogen in the mixed gas is (0.8-1.0):1; more preferably, it is 1:1.

[0048] When the volume ratio is 1:1, half of the hydrogen gas will remain after the reaction in step (1) is completed, and it will be used for the reductive amination reaction in step (2).

[0049] Preferably, in this invention, the C 10 -C 20 The molar ratio of bio-based diene cycloolefins and ammonia is 1:

[0050] (2.2-3.0); more preferably 1:(2.2-2.5); even more preferably 1:2.2.

[0051] The ammonia gas introduction rate is preferably 0.1-0.2 mol / h.

[0052] If the amount of ammonia is insufficient (below 2.2:1), it will lead to an increase in monoammoniation products. If the amount of ammonia is excessive (above 3.0:1), it will trigger an imine polymerization side reaction. Both of these will reduce the selectivity of bio-based cycloalkyl diamines.

[0053] Preferably, in this invention, the reaction in step (1) requires stepwise temperature and pressure control:

[0054] In the first stage, the temperature is 95℃-105℃ and the pressure is 2.5-3.5 MPa;

[0055] The second stage involves a temperature of 115℃-125℃ and a pressure of 4.5-5.5 MPa.

[0056] More preferably, the temperature of the first stage is 100°C and the pressure is 3 MPa;

[0057] More preferably, the temperature of the second stage is 120°C and the pressure is 5 MPa.

[0058] The reaction time in step (1) is preferably 4-5 h.

[0059] The first stage makes C 10 -C 20 In bio-based diene cycloolefins, the exocyclic double bond is preferentially converted, and the second stage results in C 10 -C 20 In bio-based diene cyclic alkenes, intracyclic double bonds are preferentially converted.

[0060] Preferably, the reaction temperature in step (2) of this invention is 120℃-140℃; more preferably, it is 120℃, 130℃ or 140℃.

[0061] Preferably, the reaction pressure is 5-7 MPa; more preferably 5 MPa, 6 MPa or 7 MPa.

[0062] The reaction time is preferably 5-6 h.

[0063] In the above preparation method, the organic weak acid is an inhibitor, which aims to effectively inhibit the condensation reaction of aldehyde and ammonia and the imine polymerization reaction, avoid the consumption of cycloalkanedialdehyde intermediate by byproducts, further improve the selectivity of bio-based cycloalkanediamine, and at the same time not affect the catalyst activity and product purity.

[0064] Preferably, the organic weak acid is selected from phosphoric acid or formic acid;

[0065] More preferably, the amount of the organic weak acid added is the C 10 -C 20 The bio-based diene cycloolefin is 0.5wt%-1.0wt%; more preferably 0.5wt%, 0.75wt% or 1.0wt%.

[0066] Preferably, the phosphine-containing host ligand in the cobalt-based catalyst is selected from monodentate phosphine ligands.

[0067] The monodentate phosphine ligands include, but are not limited to, triphenylphosphine (PPh3), triphenyl phosphite (P(OPh)3), tricyclohexylphosphine (Pcy3), tri-tert-butylphosphine (P(t-Bu)3), tri-n-butylphosphine (P(n-Bu)3), or tri-n-octylphosphine (P(n-Oct)3), etc.

[0068] In the embodiments of the present invention, triphenylphosphine (PPh3) or triphenyl phosphite (P(OPh)3) is preferably used.

[0069] Preferably, the cobalt-based catalyst further includes a coligand selected from N-methylimidazolium or pyridine-N-oxide;

[0070] Preferably, the cobalt-based metal center of the present invention is selected from one or more of cobalt, octacarbonyldicobalt (Co2(CO)8)tetracarbonylcobalt hydrogen, or tetracarbonylcobalt anion;

[0071] Preferably, the rhodium-based metal center is selected from one or more of rhodium, rhodium acetylacetonate dicarbonyl (Rh(acac)(CO)2), tetrarhodium dodecylcarbonyl, rhodium diiodocarboxylate anion, and rhodium triphenylphosphine carbonyl hydrogen.

[0072] Preferably, the bidentate phosphine ligand is selected from 4,5-bis(diphenylphosphine-9,9-dimethyloxanthracene) (Xantphos) or biphenyl bisphosphine (BISBI); preferably, the support A is selected from mesoporous SiO2 or copper-based metal-organic frameworks.

[0073] The pore diameter of the carrier A is 1.5-2.0 nm.

[0074] The mesoporous SiO2 is more preferably MCM-41;

[0075] The copper-based metal-organic framework is more preferably MOF-199;

[0076] Preferably, the carrier B is selected from aluminum oxide, silicon dioxide, or iron oxide.

[0077] The iron oxide is preferably supported by ferric oxide.

[0078] Preferably, the transition metal single atom is selected from rhodium or platinum;

[0079] The dispersion of the transition metal nitrogen atoms is >99%.

[0080] Preferably, the phosphine ligand is selected from diphenylchlorophosphine or the product of its reaction with substance A;

[0081] The substance A is selected from one or more of 1,4-dibromobutane, 1,2-dibromoethane, 1,3-dibromopropane, 2,2'-bis(bromomethyl)-1,1'-biphenyl, and 4,5-bis(chloromethyl)-9,9-dimethyloxanthracene.

[0082] In the preparation method described in this invention, the molar ratio of elemental rhodium to bidentate phosphine ligand in the rhodium-based catalyst is preferably 1:(2.0-2.5).

[0083] The preferred molar ratio of elemental cobalt to phosphine-containing main ligand in the cobalt-based catalyst is 1:(3-5).

[0084] The preferred molar ratio of elemental cobalt to coligand in the cobalt-based catalyst is 1:(1.5-2.5).

[0085] In some specific embodiments of the present invention, step (1) of the above preparation method is to mix the bio-based diene cycloolefin and the first catalyst, and then introduce synthesis gas. By stepwise temperature and pressure control, the two double bonds of the bio-based diene cycloolefin undergo hydroformylation reaction to generate a dialdehyde intermediate (cycloalkyl dicarboxaldehyde intermediate), which is then directly used in step (2) for reductive amination reaction to prepare the bio-based cycloalkyl diamine. Specifically, ammonia is introduced into the reaction system S1 containing the dialdehyde intermediate, and then a second catalyst and an organic weak acid are added to allow the two aldehyde groups of the dialdehyde intermediate to undergo reductive amination reaction simultaneously to convert into amino groups, thereby preparing the bio-based cycloalkyl diamine.

[0086] After the reaction in step (2) of the above preparation method is completed, the catalyst is also recycled.

[0087] The recovery of the catalyst described in this invention includes, in sequence, cooling and depressurization, filtration, distillation, and washing.

[0088] The catalyst includes a first catalyst and a second catalyst.

[0089] The recovered catalyst can be recycled, and its activity retention rate is >85% after more than 5 cycles.

[0090] The catalyst used in the method described in this invention is recyclable, which further reduces production costs. Moreover, the reaction conditions are mild, with no serious pollutant emissions, making it environmentally friendly.

[0091] This invention converts low-cost bio-based diene-cycloolefins into high-value-added bio-based cycloalkyl diamines, thus expanding the applications of the bio-based diene-cycloolefins.

[0092] The preparation method of the present invention uses bio-based diene cycloalkene as raw material. Utilizing the two carbon-carbon double bonds in its molecular structure, the two double bonds are first converted into aldehyde groups (-CHO) through a hydroformylation reaction to obtain a dialdehyde intermediate. Without the need for separation and purification, it is directly subjected to a reducing ammoniation reaction in the same reaction system to convert the aldehyde group of the dialdehyde intermediate into an amino group (-CH2NH2), finally yielding high-purity bio-based cycloalkyl diamine.

[0093] The preparation method described in this invention achieves the green and efficient preparation of high-purity bio-based cycloalkyl diamines by cascading hydroformylation and reductive amination reactions in a one-pot process.

[0094] When preparing bio-based cycloalkyldiamines using the preparation method described in this invention, the selectivity of the bio-based cycloalkyldiamine is ≥95%. This invention also provides a bio-based cycloalkyldiamine prepared by the above-described preparation method.

[0095] The purity of the bio-based cycloalkyl diamine is ≥98%;

[0096] The bio-based cycloalkyl diamine has a bio-based content of ≥90%.

[0097] The bio-based cycloalkyl diamine prepared by the method described in this invention has over 90% carbon derived from renewable biomass resources, with only a small amount of carbon from fossil-based raw materials, making it a green chemical with high bio-based content. This invention also provides the application of the described bio-based cycloalkyl diamine in the preparation of epoxy resin curing agents, polyamide monomers, or high-end corrosion inhibitors.

[0098] Compared with the prior art, the preparation method of bio-based cycloalkyldiamine provided by the present invention includes the following steps: (1) C 10 -C 20 Bio-based diene cycloolefins, a first catalyst, and syngas are mixed and reacted to obtain C-containing... 12 -C 22 The reaction system S1 for the intermediate cycloalkanedicarboxaldehyde; (2) S1 is mixed with ammonia, a second catalyst and a weak organic acid to react and obtain C. 12 -C 22 A bio-based cycloalkyl diamine is described; wherein the synthesis gas comprises carbon monoxide and hydrogen; the first catalyst is selected from rhodium-based catalysts, cobalt-based catalysts, or mesoporous confined transition metal single-atom catalysts; the rhodium-based catalyst comprises a rhodium-based metal center and a bidentate phosphine ligand; the cobalt-based catalyst comprises a cobalt-based metal center and a phosphine-containing main ligand; the mesoporous confined transition metal single-atom catalyst comprises a support A and a transition metal single atom, wherein the transition metal single atom is supported on the surface and within the pores of support A, and the phosphine ligand is grafted into the pores; the second catalyst consists of a support B and a transition metal single atom supported on its surface. The preparation method of this invention uses bio-based diene cycloolefins as starting materials. Through the selection of catalysts and the control of process conditions, side reactions are effectively suppressed, and efficient tandem hydroformylation and reductive amination are achieved. This simplifies the production process, improves product yield and purity, realizes the green preparation of cycloalkyl diamines, reduces production costs, and has good prospects for industrial application. Detailed Implementation

[0099] To further illustrate the present invention, the preparation method of bio-based cycloalkyl diamine and the bio-based cycloalkyl diamine provided by the present invention will be described in detail below with reference to the embodiments.

[0100] The following examples all use the ASTM D6866 standard test method to determine the bio-based carbon content of the samples.

[0101] Example 1

[0102] (1) Catalyst preparation

[0103] In a nitrogen-protected glove box, 100 mL of anhydrous and oxygen-free toluene was added to a 500 mL three-necked flask, followed by 2.84 g (0.011 mol) of Rh(acac)(CO)2 (rhodium dicarbonyl acetylacetone). The mixture was stirred until completely dissolved, and the solution turned purple-red. 12.64 g (0.022 mol) of Xantphos (4,5-bis(diphenylphosphine-9,9-dimethyloxanthracene)) was slowly added, and the mixture was stirred at room temperature for 30 min. The solution gradually turned bright yellow, yielding a homogeneous Rh-Xantphos catalyst system with a molar ratio of Rh to Xantphos of 1:2.0. The system was sealed and stored for later use.

[0104] (2) Preparation of bio-based cycloalkyl diamine

[0105] Hydroformylation reaction: The 200 mL high-pressure reactor was washed and dried, and purged with nitrogen three times. 136.2 g (1.0 mol) of limonene (98.5% purity) and the aforementioned Rh-Xantphos catalyst system (which can be represented as [Rh(acac)(CO)2)) were added. + Xantphos→[Rh(acac)(CO)(Xantphos)] + 20 mL of CO (containing 0.0022 mol of Rh) was used to seal the reactor. Syngas (CO:H2 = 1:1, volume ratio) was introduced to replace the air in the reactor three times. The reaction pressure was adjusted to 3 MPa, and the temperature was raised to 100 °C. The reaction was stirred for 2 h (first stage, preferential conversion of exocyclic alkenes). Subsequently, the temperature was raised to 120 °C and the pressure was increased to 5 MPa. The reaction was stirred for another 3 h (second stage, conversion of intracyclic double bonds) to complete the hydroformylation reaction and obtain limonene dialdehyde intermediate. The yield of the dialdehyde intermediate was 92.3%, the content of the monoaldehyde intermediate was ≤5.1%, and there were no obvious over-hydrogenation or isomerization byproducts.

[0106] Reductive amination reaction: Keep the reactor sealed and slowly and continuously introduce ammonia (introduction rate 0.1 mol / h), controlling the molar ratio of ammonia to limonene to be 2.2:1. Add 0.68 g of a single-atom Ru-based hydrogenation catalyst (Al2O3 as support, Ru as active component with a loading of 0.5%), and then add 0.68 g of phosphoric acid (organic weak acid inhibitor) (0.5% of the mass of limonene). Adjust the reaction temperature to 120℃ and the pressure to 5 MPa, and stir the reaction for 5 h to simultaneously amination the two aldehyde groups of the dialdehyde intermediate.

[0107] Post-processing: After the reaction was completed, the temperature was lowered to below 80℃, and the pressure was slowly released to atmospheric pressure. The Rh-Xantphos catalyst and Ru-based hydrogenation catalyst were recovered by filtration. The reaction solution was transferred to a distillation apparatus and distilled under a vacuum of -0.09 MPa and a top temperature of 180℃-200℃. The fraction was collected, washed twice with deionized water, separated, and dried to obtain 168.3 g of bio-based cycloalkyl diamine. The product purity was 98.6%, the diamine selectivity was 95.7%, the total content of monoamines and other byproducts was 1.4%, and the bio-based content was 91.7%.

[0108] (3) Catalyst cycle performance test

[0109] The Rh-Xantphos catalyst and Ru-based hydrogenation catalyst recovered by filtration were reused in the above preparation process. After five cycles, the yield of hydroformylation of dialdehyde was 89.7%, the selectivity for reducing aminated diamine was 94.2%, and the catalyst activity retention rate was 88.3%, which meets the requirements for industrial recycling.

[0110] Example 2

[0111] (1) Catalyst preparation

[0112] Under nitrogen protection, 150 mL of anhydrous ethanol was added to a 500 mL three-necked flask, followed by 5.92 g (0.017 mol) of Co2(CO)8 (cobalt carbonyl), and stirred until completely dissolved, resulting in an orange-red solution. Then, 36.16 g (0.136 mol) of PPh3 (triphenylphosphine) and 2.80 g (0.034 mol) of N-methylimidazole (NMI) were added sequentially. The mixture was heated to 50 °C and stirred for 1 h to obtain a Co-PPh3-NMI catalyst system with a molar ratio of Co, PPh3, and NMI of 1:4:2. The system was then cooled to room temperature and sealed for later use.

[0113] (2) Preparation of bio-based cycloalkyl diamine

[0114] Hydroformylation reaction: The 200mL high-pressure reactor was cleaned and dried, and purged with nitrogen three times. 136.2g (1.0mol) of limonene (98.2% purity) and 30mL of the above Co-PPh3-NMI catalyst system (Co2(CO)6(PPh3)2) (containing 0.0034mol of Co) were added, and the reactor was sealed. Syngas (CO:H2=1:1) was introduced and purged three times. The pressure was adjusted to 3MPa, and the temperature was raised to 100℃. The reaction was stirred for 2.5h (first stage). The temperature was raised to 120℃ and the pressure was increased to 5MPa. The reaction was continued for 2.5h (second stage) to complete the hydroformylation reaction. The yield of the dialdehyde intermediate was 89.5%, the content of the monoaldehyde intermediate was 6.3%, and there were no obvious by-products.

[0115] Reduction ammoniation reaction: Ammonia was slowly and continuously introduced into the reactor (introduction rate 0.15 mol / h), and the molar ratio of ammonia to limonene was controlled at 2.5:1. 0.68 g of a single-atom Pt-based hydrogenation catalyst (Al2O3 as support, Pt as active component with a loading of 0.5%) was added, along with 1.02 g of formic acid (an organic weak acid inhibitor) (0.75% of the mass of limonene). The temperature was adjusted to 130℃ and the pressure to 6 MPa, and the reaction was stirred for 5.5 h.

[0116] Post-processing: Cooling and depressurization, filtration to recover the catalyst, and distillation, washing and drying of the reaction solution yielded 165.7g of bio-based cycloalkyl diamine. The test results showed that the product purity was 98.2%, the diamine selectivity was 95.1%, the total content of monoamine and by-products was 1.8%, and the bio-based content was 91.8%.

[0117] Example 3

[0118] (1) Catalyst preparation

[0119] MCM-41 mesoporous SiO2 molecular sieve (full name Mobil Composition of Matter No. 41, a commercially available product) was placed in a muffle furnace and calcined at 500℃ for 4 hours to remove the template agent. After cooling to room temperature, the pretreated mesoporous support was obtained, and its pore size was measured to be 1.8 nm using a nitrogen physical adsorption analyzer. 200 mL of toluene was added to a 500 mL three-necked flask, followed by 50 g of the pretreated MCM-41 support and 11.32 g (0.05 mol) of diphenylphosphine. The mixture was heated to 80℃ and refluxed for 12 hours. After cooling to room temperature, the mixture was filtered, washed three times with toluene, and dried under vacuum for 6 hours to obtain the phosphine-functionalized mesoporous support. The above-mentioned phosphine-functionalized support was added to 300 mL of RhCl3 aqueous solution (concentration 0.02 mol / L), the pH was adjusted to 8 with ammonia, and the mixture was stirred at room temperature for 24 h. After filtration, the solid was washed with deionized water until neutral. The resulting solid was placed in a tube furnace and reduced at 300 °C for 2 h under an H2 / Ar (volume ratio 1:1) atmosphere. After cooling to room temperature, a mesoporous confined single-atom Rh catalyst was obtained. The results showed that the Rh single-atom dispersion was 99.2% and the loading was 0.3%.

[0120] (2) Preparation of bio-based cycloalkyl diamine

[0121] Hydroformylation reaction: The 200mL high-pressure reactor was cleaned and dried, and purged with nitrogen three times. 136.2g (1.0mol) of limonene (98.7% purity) and 5.45g (0.0022mol) of the above-mentioned mesoporous confined single-atom Rh catalyst were added, and the reactor was sealed. Syngas (CO:H2=1:1) was introduced and purged three times. The pressure was adjusted to 3MPa, and the temperature was raised to 100℃. The reaction was stirred for 2h (first stage). The temperature was raised to 120℃ and the pressure was raised to 5MPa. The reaction was continued for 3h (second stage) to complete the hydroformylation reaction. The yield of the dialdehyde intermediate was 95.1%, the content of the monoaldehyde intermediate was ≤3.2%, and there were no excessive hydrogenation or isomerization byproducts (the pore confinement effect effectively inhibited the dissociation of the intermediate).

[0122] Reduction ammoniation reaction: Ammonia was slowly and continuously introduced into the reactor (introduction rate 0.2 mol / h), and the molar ratio of ammonia to limonene was controlled at 3.0:1. 0.68 g of a single-atom Ru-based hydrogenation catalyst and 1.36 g of phosphoric acid (1.0% of the mass of limonene) were added. The temperature was adjusted to 140 °C and the pressure to 7 MPa, and the reaction was stirred for 6 h.

[0123] Post-processing: Cooling and depressurization, filtration to recover the mesoporous confined single-atom Rh catalyst and Ru-based hydrogenation catalyst. After purification by distillation, 170.1 g of bio-based cycloalkyl diamine was obtained. The test showed that the product purity was 99.1%, the diamine selectivity was 97.3%, and the total content of monoamine and by-products was 0.9%.

[0124] Comparative Example 1

[0125] Comparative experiment without the use of bidentate phosphine ligands

[0126] Except for replacing the catalyst system with a monophosphine system of Rh(acac)(CO)2 and PPh3 (molar ratio 1:2.0), the other operations were exactly the same as in Example 1. The results showed that the yield of dialdehyde hydroformylation was only 68.3%, the content of monoaldehyde intermediate was 22.7%, and the content of over-hydrogenation byproducts was 8.1%. The final bio-based cycloalkyl diamine purity was 92.5%, and the diamine selectivity was 75.3%, which was much lower than the effect of Example 1 of this invention. This proves that bidentate phosphine ligands can significantly improve the selectivity of dihydroformylation and suppress side reactions.

[0127] Comparative Example 2

[0128] Comparative experiment without using a step-by-step temperature control strategy

[0129] The only difference between the hydroformylation reaction and Example 1 was that the stepwise temperature control was not used; the temperature was directly controlled at 120°C and the pressure at 5 MPa for 5 hours. The results showed that the yield of the hydroformylation dialdehyde was 80.5%, the content of the monoaldehyde intermediate was 15.3%, and the reaction of the intracyclic double bond was incomplete. The final bio-based cycloalkyl diamine had a purity of 96.1% and a diamine selectivity of 88.7%, proving that the stepwise temperature control strategy can effectively control the sequential reaction of the two double bonds and improve the yield of the dialdehyde and the diamine selectivity.

[0130] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a bio-based cycloalkyl diamine, characterized in that, Includes the following steps: (1) C 10 -C 20 Bio-based diene cycloolefins, a first catalyst, and syngas are mixed and reacted to obtain C-containing... 12 -C 22 The reaction system S1 for the cycloalkanedicarboxaldehyde intermediate; (2) S1 is mixed with ammonia, a second catalyst and a weak organic acid to react and obtain C. 12 -C 22 Bio-based cycloalkyl diamine; The synthesis gas includes carbon monoxide and hydrogen. The first catalyst is selected from rhodium-based catalysts, cobalt-based catalysts, or mesoporous confined transition metal single-atom catalysts; The rhodium-based catalyst comprises a rhodium-based metal center and a bidentate phosphine ligand; The cobalt-based catalyst comprises a cobalt-based metal center and a phosphine-containing host ligand; The mesoporous confined transition metal single-atom catalyst includes a support A and a transition metal single atom, wherein the transition metal single atom is supported on the surface of the support A and within the pores, and a phosphine ligand is grafted into the pores. The second catalyst consists of a support B and transition metal single atoms supported on its surface.

2. The preparation method according to claim 1, characterized in that, The C 10 -C 20 The bio-based diene cycloolefins are selected from limonene, α-pinene dimer, or coniferene.

3. The preparation method according to claim 2, characterized in that, The volume ratio of carbon monoxide to hydrogen in the mixed gas is (0.8-1.2):1; The C 10 -C 20 The molar ratio of bio-based diene cycloolefin and ammonia is 1:(2.2-3.0).

4. The preparation method according to any one of claims 1-3, characterized in that, The reaction in step (1) needs to be carried out in stages with controlled temperature and pressure: In the first stage, the temperature is 95℃-105℃ and the pressure is 2.5-3.5 MPa; The second stage involves a temperature of 115℃-125℃ and a pressure of 4.5-5.5 MPa.

5. The preparation method according to claim 4, characterized in that, The reaction temperature in step (2) is 120℃-140℃; The reaction is carried out at a pressure of 5-7 MPa.

6. The preparation method according to claim 1 or 2, characterized in that, The organic weak acid is selected from phosphoric acid or formic acid; The amount of the organic weak acid added is C 10 -C 20 0.5wt%-1.0wt% of bio-based diene cycloolefins.

7. The preparation method according to claim 1, characterized in that, The phosphine-containing main ligand in the cobalt-based catalyst is selected from triphenylphosphine or triphenyl phosphite; The cobalt-based catalyst also includes a coligand selected from N-methylimidazolium or pyridine-N-oxide.

8. The preparation method according to claim 1, characterized in that, The cobalt-based metal center is selected from one or more of cobalt, octacarbonyldicobalt, tetracarbonylcobalt hydrogen, or tetracarbonylcobalt anion; The rhodium-based metal center is selected from one or more of rhodium, rhodium acetylacetonate dicarbonyl, tetrarhodium dodecylcarbonyl, rhodium diiodocarboxylate diiodocarboxylate anion, and rhodium triphenylphosphine carbonyl hydrogen. The bidentate phosphine ligand is selected from 4,5-bis(diphenylphosphine-9,9-dimethyloxanthracene) or biphenylbisphosphine.

9. The preparation method according to claim 1, characterized in that, The carrier A is selected from mesoporous SiO2 or copper-based metal-organic framework materials; The carrier B is selected from aluminum oxide, silicon dioxide, or iron oxide; The transition metal single atom is selected from rhodium or platinum; The phosphine ligand is selected from diphenylchlorophosphine or the product of its reaction with substance A; The substance A is selected from one or more of 1,4-dibromobutane, 1,2-dibromoethane, 1,3-dibromopropane, 2,2'-bis(bromomethyl)-1,1'-biphenyl, and 4,5-bis(chloromethyl)-9,9-dimethyloxanthracene.

10. A bio-based cycloalkyl diamine, characterized in that, Prepared by the preparation method according to any one of claims 1-10; The purity of the bio-based cycloalkyl diamine is ≥98%; The bio-based cycloalkyl diamine has a bio-based content of ≥90%.