Patent Description:
Phosphite ester compounds are known in the art as catalytic systems associated with hydrocyanation of alkenes. In related technologies, phosphite compounds are usually prepared by purging R-OH and phosphorus chloride compounds with an inert gas or adding an organic base acid binding agent to the R-OH and the phosphorus chloride compounds.

During a process for preparing a bidentate phosphorus-containing ligand and a multidentate phosphorus-containing ligand in the related art, a liquid amine compound is normally added as an acid binding agent to react with a generated hydrogen chloride to generate an ammonium hydrochloride. After a reaction is finished, a target product is purified by filtration, removal of solvent, and column chromatography. However, the method in related art generally has problems such as a large consumption amount of acid binding agent, an excessively high viscosity of the reaction system, a difficult post-processing of the acid binding agent, and a complicated recycling procedure, which increase a cost of wastes treatment.

<CIT> discloses that a method for producing organophosphites, organophosphonites and organophosphinites by the condensation of phosphorus trihalides or organophosphorus halides with organic compounds that carry hydroxy groups, in the presence of polymeric alkaline ion-exchange resins; the inventive method permits the production of trivalent organophosphorus compounds, which can be used e.g. as ligands in rhodium complexes that can be utilised as a catalyst in hydroformylation.

Therefore, how to solve problems such as a high salt content, a high viscosity and a difficult post-processing of a system after using the acid binding agent in a process for preparing phosphorus-containing ligand compounds, and how to solve problems of a low selectivity and a low conversion rate in the process for preparing phosphorus-containing ligand compounds are challenges in the art. Meanwhile, for some phosphorus-containing ligand compounds including sensitive groups (such as double bonds, etc.), it is also an urgent need in the art to prepare them by faster methods under milder conditions.

Details of one or more embodiments of the present disclosure are set forth in the following description. Other features, objects and advantages of the present disclosure will become apparent from the specification and the claims.

In some embodiments of the present disclosure, a method for preparing a phosphorus-containing ligand is provided. In the method, polypyridine ionic liquid-loaded porous microspheres are employed as catalysts and hydrogen chloride produced by the reaction are removed from a reaction device, so that the method may have an excellent reaction selectivity and an excellent yield.

A method for preparing a phosphorus-containing ligand includes the following steps:.

In an embodiment, the first polypyridine ionic liquid-loaded porous microspheres includes a polypyridine ionic liquid, and a structural formula of the polypyridine ionic liquid is shown in Formula (<NUM>),
<CHM>
in Formula (<NUM>), R is selected from a C<NUM>-C<NUM> linear chain alkyl group or a C<NUM>-C<NUM> branched chain alkyl group, wherein R<NUM> and R<NUM> is independently selected from hydrogen atom, halogen atom, C<NUM>-C<NUM> alkyl group, C<NUM>-C<NUM> alkoxy group, C<NUM>-C<NUM> alkanoyl group, aryl group, heteroaryl group, cyano group, or nitro group, m is an integer in a range of <NUM> to <NUM>, and Q is a direct bond or a divalent linking group.

In an embodiment, Q is selected from
<CHM>
<CHM>
wherein R<NUM>, R<NUM>, R<NUM>, and R<NUM> are independently selected from hydrogen atom, halogen atom, C<NUM>-C<NUM> alkyl group, C<NUM>-C<NUM> alkoxy group, C<NUM>-C<NUM> alkanoyl group, aryl group, heteroaryl group, cyano group, or nitro group, wherein Q<NUM> is selected from a direct bond or a divalent linking group, m<NUM> is an integer in a range of <NUM> to <NUM>, and m<NUM> is an integer in a range of <NUM> to <NUM>.

In an embodiment, Q<NUM> is selected from
<CHM>
-(CH<NUM>)n<NUM>-, -(CH<NUM>O)n<NUM>-, substituted aryl group, or unsubstituted aryl group, and n<NUM> and n<NUM> are independently selected from integers in a range of <NUM> to <NUM>.

In an embodiment, the first polypyridine ionic liquid-loaded porous microspheres includes polystyrene porous microspheres, particle sizes of the polystyrene microspheres are in a range of <NUM> to <NUM>, and a relative deviation of the particle sizes is less than <NUM>%.

In an embodiment, a BET specific surface area of the first polypyridine ionic liquid-loaded porous microspheres is in a range of <NUM><NUM>/g to <NUM><NUM>/g, and an average aperture size of apertures in the first polypyridine ionic liquid-loaded porous microspheres is in a range of <NUM> to <NUM>.

In an embodiment in Formula (<NUM>), a structural formula of the substituted aryloxy groups is
<CHM>
wherein Rx and Ry are independently selected from hydrogen atom, halogen atom, nitrile group, C<NUM>-C<NUM> alkyl group, C<NUM>-C<NUM> alkoxy group, C<NUM>-C<NUM> alkanoyl group, C<NUM>-C<NUM> ester group, C<NUM>-C<NUM> sulfonate group, vinyl group, propenyl group, acryloyl group, acrylate group, or methacryloyl group.

In an embodiment, when both X and Y are selected from
<CHM>
X and Y are not cyclized. In an embodiment, when both X and Y are selected from nitrogen-containing heterocyclic groups, X and Y are not cyclized, or X and Y are cyclized via a single bond or methylene. In an embodiment, when X is selected from
<CHM>
and Y is selected from nitrogen-containing heterocyclic groups, X and Y are cyclized via methylene.

In an embodiment, the nitrogen-containing heterocyclic groups are selected from
<CHM>
<CHM>
wherein Rx and Ry are independently selected from hydrogen atom, halogen atom, nitrile group, C<NUM>-C<NUM> alkyl group, C<NUM>-C<NUM> alkoxy group, C<NUM>-C<NUM> alkanoyl group, C<NUM>-C<NUM> ester group, Ci-Cio sulfonate group, vinyl group, propenyl group, acryloyl group, acrylate group, or methacryloyl group.

In an embodiment, both X and Y are selected from nitrogen-containing heterocyclic groups, and X and Y are cyclized via the single bond or the methylene to form a structure selected from the group consisting of
<CHM>
<CHM>.

In an embodiment, in Formula (<NUM>), Z is selected from
<CHM>
<CHM>
<CHM>
<CHM>
or
<CHM>
wherein R<NUM> and R<NUM> are independently selected from hydrogen atom, halogen atom, nitrile group, C<NUM>-C<NUM> alkyl group, C<NUM>-C<NUM> alkoxy group, C<NUM>-C<NUM> alkanoyl group, C<NUM>-C<NUM> ester group, C<NUM>-C<NUM> sulfonate group, vinyl group, propenyl group, acryloyl group, acrylate group, or methacryloyl group.

In an embodiment, in Formula (<NUM>), n is an integer in a range of <NUM> to <NUM>.

In an embodiment, in the step of mixing the first mixture with the second mixture in the reaction device to obtain the reaction mixture, a molar ratio of the phosphorus chloride compound to the compound as shown in Formula (<NUM>) is in a range of <NUM>:(<NUM>/x) to <NUM>. <NUM>: (<NUM> /x), x is equal to n in Formula (<NUM>), and a molar ratio of nitrogen atoms in the first polypyridine ionic liquid-loaded porous microspheres to hydroxyl groups in the compound as shown in Formula (<NUM>) is in a range of <NUM>:<NUM> to <NUM>:<NUM>.

In an embodiment, a molar concentration of the phosphorus chloride compound in the first mixture is in a range of <NUM> mol/L to <NUM> mol/L, and a molar concentration of the compound as shown in Formula (<NUM>) in the second mixture is in a range of <NUM> mol/L to <NUM> mol/L.

In an embodiment, in the step of mixing the first mixture with the second mixture in the reaction device to make the first mixture react with the second mixture to obtain the reaction mixture, a reaction temperature is in a range of <NUM> to <NUM> degrees centigrade, and a reaction time is in a range of <NUM> hour to <NUM> hours.

In an embodiment, in the step of mixing the first mixture with the second mixture in the reaction device to make the first mixture react with the second mixture to obtain the reaction mixture, the second mixture is added into the first mixture in batches.

In an embodiment, in the step of adding the second mixture into the first mixture in batches, an adding duration is in a range of <NUM> hours to <NUM> hours.

In an embodiment, the step of filtrating the reaction mixture to obtain the filter liquor after the reaction further includes recovering second polypyridine ionic liquid-loaded porous microspheres.

In an embodiment, after the recovering the second polypyridine ionic liquid-loaded porous microspheres, the recovered second polypyridine ionic liquid-loaded porous microspheres are washed, dried and re-used for preparing the first mixture.

In an embodiment, the step of mixing the first mixture with the second mixture in the reaction device to make the first mixture react with the second mixture to obtain the reaction mixture further includes blowing a protective gas in to the reaction device to remove the generated hydrogen chloride out from the reaction device, so as to co-produce hydrogen chloride.

In Chinese patent No. <CIT>, a synthetic method of bis(<NUM>,<NUM>-di-tert-butylphenyl) pentaerythritol diphosphate ester was provided. In the synthetic method, nitrogen gas was introduced to reactants and stirred, and hydrogen chloride generated in the reaction was absorbed by a sodium hydroxide solution. In Chinese patent No. <CIT>, a method for preparing a phosphite ester antioxidant was provided. In the method, a slight positive pressure of a system was maintained during a reaction, and generated hydrogen chloride was completely discharged into a hydrogen chloride absorption system to generate hydrochloric acid.

In Chinese patent No. <CIT>, a method for preparing tridentate phosphorus-containing ligands was provided. In the method, <NUM>, <NUM>', <NUM>-trihydroxybiphenyl was reacted with dipyrrole phosphorus chloride in the presence of an anhydrous triethylamine, and after a reaction was completed, a triethylamine hydrochloride was filtered, and a target product with a yield of <NUM>% was obtained by removal of solvent, a crude purification through column chromatography and a recrystallization using methanol. Chinese patent No. <CIT> disclosed a method for preparing a tetradentate phosphorus ligand. In the method, <NUM>, <NUM>', <NUM>, <NUM>'-tetrahydroxy-<NUM>, <NUM>'-biphenyl was reacted with dipyrrole phosphorus chloride in the presence of an anhydrous triethylamine, and after a reaction was completed, a target product with a yield of <NUM>% was obtained by a filtration, a removal of solvent, and column chromatography.

Chinese patent No. <CIT> disclosed a method for preparing a pentaerythritol phosphite ester antioxidant. In the method, pentaerythritol, a solvent, phosphorus trichloride, and <NUM>, <NUM>-di-tertbutyl-p-cresol were used as raw materials and a weak base type macroporous ion exchange resin was used as a catalyst to prepare pentaerythritol phosphite ester. Hydrogen chloride gas generated in a reaction was removed from a system. The catalyst after the reaction was easily separated and recovered, and may be regenerated and reused. However, using the weak base type macroporous ion exchange resin as a catalyst has disadvantages such as a high cost, a large consumption amount, and a complicated regeneration treatment. The regeneration treatment may include steps of acid washing, alkali washing, distilled water washing to neutrality, and drying, which is complicated in operation, large in energy consumption, and produces a large amount of waste water and waste salt.

In order to facilitate understanding of the present disclosure, the present disclosure will be more fully described below with reference to the relevant drawings which give the preferred embodiments of the present disclosure.

The present disclosure provides a method for preparing a phosphorus-containing ligand , which includes the following steps:.

It should be noted that the polypyridine ionic liquid-loaded porous microspheres may include polystyrene porous microspheres and polypyridine ionic liquid loaded on the polystyrene porous microspheres. When preparing the polypyridine ionic liquid-loaded porous microspheres, the polystyrene porous microspheres can play a role of "seed crystal". Specifically, pyridine monomers are physically adsorbed on the polystyrene porous microspheres, and polymerized to grow into a polypyridine ionic liquid by pores of the polystyrene porous microspheres. Thus, the formed polypyridine ionic liquid-loaded porous microspheres may have more active sites.

Therefore, in the present disclosure, when polypyridine ionic liquid-loaded porous microspheres are used as catalysts, the more active sites of the polypyridine ionic liquid-loaded porous microspheres can effectively improve reaction selectivity and yield. Meanwhile, because the polypyridine ionic liquid-loaded porous microspheres are in sphere-shaped, a post-processing thereof is simple, and properties of the polypyridine ionic liquid-loaded porous microspheres are more stable, a cycle performance of the polypyridine ionic liquid-loaded porous microspheres is good, thus the polypyridine ionic liquid-loaded porous microspheres are easy to be recycled and reused.

In an embodiment, a structural formula of the polypyridine ionic liquid is shown in Formula (<NUM>),
<CHM>.

In Formula (<NUM>), R is selected from a Ci-Cio linear chain alkyl group or a Ci-Cio branched chain alkyl group.

In Formula (<NUM>), R<NUM> and R<NUM> are independently selected from hydrogen atom, halogen atom, C<NUM>-C<NUM> alkyl group, C<NUM>-C<NUM> alkoxy group, C<NUM>-C<NUM> alkanoyl group, aryl group, heteroaryl group, cyano group, or nitro group, and m is an integer in a range of <NUM> to <NUM>. In some embodiments, R<NUM> and R<NUM> are each independently selected from hydrogen atom, fluorine atom, chlorine atom, bromine atom, methyl group, ethyl group, n-propyl group, isopropyl group, methoxy group, ethoxy group, n-propyl oxy group, isopropoxy group, cyano group, acetyl group, or propionyl group.

In Formula (<NUM>), Q is a direct bond or a divalent linking group. In some embodiments, Q is selected from
<CHM>
<CHM>
In the present disclosure, a direct bond means that two adjacent groups are directly bonded.

In some embodiments, R<NUM>, R<NUM>, R<NUM>, and R<NUM> are independently selected from hydrogen atom, halogen atom, C<NUM>-C<NUM> alkyl group, C<NUM>-C<NUM> alkoxy group, C<NUM>-C<NUM> alkanoyl group, aryl group, heteroaryl group, cyano group, or nitro group, where m<NUM> is an integer in a range of <NUM> to <NUM>, and m<NUM> is an integer in a range of <NUM> to <NUM>. In some embodiments, R<NUM>, R<NUM>, R<NUM>, and R<NUM> are independently selected from hydrogen atom, fluorine atom, chlorine atom, bromine atom, methyl group, ethyl group, n-propyl group, isopropyl group, methoxy group, an ethoxy group, n-propoxy group, isopropoxy group, cyano group, acetyl group, or propionyl group.

In some embodiments, Q<NUM> is selected from a direct bond or a divalent linking group. In some embodiments, Q<NUM> is selected from
<CHM>
-(CH<NUM>)n<NUM>-, -(CH<NUM>O)n<NUM>-, a substituted aryl group or an unsubstituted aryl group, and n<NUM> and n<NUM> are independently selected from integers in a range of <NUM> to <NUM>.

In some embodiments, the polypyridine ionic liquid-loaded porous microspheres may include polystyrene porous microspheres. Particle sizes of the polystyrene porous microspheres are in a range of <NUM> to <NUM>, and a relative deviation of the particle sizes is less than <NUM>%.

In some embodiments, the polypyridine ionic liquid-loaded porous microspheres may have a porous structure. A BET specific surface area of the polypyridine ionic liquid-loaded porous microspheres is in a range of <NUM><NUM>/g to <NUM><NUM>/g, and an average aperture size of apertures thereof is in a range of <NUM> to <NUM>.

In some embodiments, a method for preparing the polypyridine ionic liquid-loaded porous microspheres can include the following steps.

In step (<NUM>) and step (<NUM>), concentrations of the first surfactant aqueous solution, the second surfactant aqueous solution and the third surfactant aqueous solution are in arrange of <NUM> wt% to <NUM>. In some embodiments, concentrations of the first surfactant aqueous solution, second surfactant aqueous solution and third surfactant aqueous solution are in arrange of <NUM>. 5wt% to <NUM>. In some embodiments, a time of shaking and mixing is in a range of <NUM> hours to <NUM> hours. In some embodiments, the time of shaking and mixing is in a range of <NUM> hours to <NUM> hours.

The surfactant is selected from the group consisting of a cationic surfactant, an anionic surfactant, a nonionic surfactant, or a combination thereof. In some embodiments, the surfactant is selected from the group consisting of cetyltrimethyl ammonium bromide, benzyldimethyl octadecyl ammonium chloride, ammonium dodecyl sulfate, sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, potassium dodecyl phosphate, polyvinyl alcohol, Tween-<NUM>, or a combination thereof.

In the first emulsion of step (<NUM>), a ratio of a mass of the polystyrene porous microspheres to a volume of the first surfactant aqueous solution is in a range of <NUM>: <NUM> to <NUM>: <NUM>. In the second emulsion of step (<NUM>), a volume ratio of the third organic solvent to the second surfactant aqueous solution is in a range of <NUM>:<NUM> -<NUM>:<NUM>.

In some embodiments, the third organic solvent is selected the group consisting of ethyl acetate, tetrahydrofuran, N,N-dimethylformamide, dimethyl sulfoxide, methanol, ethanol, propanol, tert-butyl alcohol, ethylene glycol, propylene glycol, glycerol, acetone, and any combinations thereof.

In step (<NUM>), a molar ratio of the pyridine monomers to the initiator is in a range of <NUM>:<NUM> to <NUM>:<NUM>, and a mass ratio of the pyridine monomers to the polystyrene porous microspheres in step (<NUM>) is in a range of <NUM>:<NUM> to <NUM>:<NUM>.

In some embodiments, a general formula of the pyridine monomers is
<CHM>
and the initiator is selected from azo initiators. In some embodiments, the initiator is at least one selected from azobisisobutyronitrile (AIBN), <NUM>, <NUM>'-Azobis(<NUM>,<NUM>-dimethyl)valeronitrile (ABVN), dimethyl azobisisobutyrate (AIBME), azobisisobutyronitrile amidine hydrochloride (AIBA), or azobisisobutylimidazoline hydrochloride (AIBI). The fourth organic solvent is at least one selected from aliphatic hydrocarbon or alicyclic hydrocarbon, halogenated aliphatic hydrocarbon or halogenated alicyclic hydrocarbon, substituted aromatic hydrocarbon or unsubstituted aromatic hydrocarbon, aliphatic ether, of cyclic ether. In some embodiments, the fourth organic solvent is at least one selected from benzene, toluene, xylene, dichloromethane, cyclohexane, n-hexane, or tetrahydrofuran.

In step (<NUM>), a temperature of the polymerization reaction is in a range of <NUM> degrees centigrade to <NUM> degrees centigrade. In some embodiments, the temperature of the polymerization reaction is in a range of <NUM> degrees centigrade to <NUM> degrees centigrade, and a time of the polymerization reaction is in a range of <NUM> hours to <NUM> hours. In some embodiments, the time of the polymerization reaction is in a range of <NUM> hours to <NUM> hours.

In step (<NUM>), the fifth organic solvent is at least one selected from ethyl acetate, tetrahydrofuran, N, N-dimethylformamide, dimethyl sulfoxide, methanol, ethanol, propanol, tert-butyl alcohol, ethylene glycol, propylene glycol, glycerol, or acetone.

A content of nitrogen element (ωN) of the cross-linked polystyrene pyridine porous microspheres obtained in step (<NUM>) is in a range of <NUM>% to <NUM>%.

In step (<NUM>), a molar amount of nitrogen element (nN) in the cross-linked polystyrene pyridine porous microspheres obtained in the step (<NUM>) conforms to a following equation: nN=mC*ωN/<NUM>, wherein mC refers to a mass of the cross-linked polystyrene pyridine porous microspheres. In some embodiments, a molar ratio of the cross-linked polystyrene-pyridine porous microspheres to the halogenated alkane (nN: nhalogenated alkane) is in a range of <NUM>: <NUM> to <NUM>: <NUM>.

In step (<NUM>), the sixth organic solvent is at least one selected from toluene, benzene, xylene, tetrahydrofuran, cyclohexane, n-hexane, or dichloromethane. The halogenated alkane is selected from Ci-Cio halogenated alkanes. In some embodiments, the halogenated alkane is at least one selected from <NUM>-chloropropane, <NUM>-chloropropane, <NUM>-bromopropane, <NUM>-bromobutane, <NUM>-bromobutane, <NUM>-iodopentane, or <NUM>-iodopentane. In some embodiments, the seventh organic solvent is at least one selected from ethyl acetate, tetrahydrofuran, N, N-dimethylformamide, dimethyl sulfoxide, methanol, ethanol, propanol, tert-butyl alcohol, ethylene glycol, propylene glycol, glycerol, or acetone.

In step (<NUM>), a reaction temperature is in a range of <NUM> degrees centigrade to <NUM> degrees centigrade. In some embodiments, the reaction temperature is in a range of <NUM> degrees centigrade to <NUM> degrees centigrade. In some embodiments, a reaction time is in a range of <NUM> hours to <NUM> hours. In some embodiments, the reaction time is in a range of <NUM> hours to <NUM> hours.

In order to obtain different phosphorus-containing ligand, in some embodiments, in phosphorus chloride compounds having a structural formula as shown in Formula (<NUM>), X and Y are independently selected from substituted aryloxy groups or nitrogen-containing heterocyclic groups.

In some embodiments, a structural formula of the substituted aryloxy group is
<CHM>
Rx and Ry are independently selected from hydrogen atom, halogen atom, nitrile group, C<NUM>-C<NUM> alkyl group, C<NUM>-C<NUM> alkoxy group, C<NUM>-C<NUM> alkanoyl group, C<NUM>-C<NUM> ester group, C<NUM>-C<NUM> sulfonate group, vinyl group, propenyl group, acryloyl group, acrylate group, or methacryloyl group.

In some embodiments, the nitrogen-containing heterocyclic group is selected from
<CHM>
or
<CHM>
wherein Rx and Ry are independently selected from hydrogen atom, halogen atoms, nitrile group, C<NUM>-C<NUM> alkyl group, C<NUM>-C<NUM> alkoxy group, C<NUM>-C<NUM> alkanoyl group, C<NUM>-C<NUM> ester group, C<NUM>-C<NUM> sulfonate group, vinyl group, propenyl group, acryloyl group, acrylate group, or methacryloyl group.

In some embodiments, when both X and Y are each selected from
<CHM>
X and Y are not cyclized; when X and Y are each selected from nitrogen-containing heterocyclic groups, X and Y are not cyclized, or X and Y are cyclized via a single bond or methylene; optionally, when X is selected from
<CHM>
and Y is selected from a nitrogen-containing heterocyclic group, X and Y are cyclized via methylene.

In some embodiments, when both X and Y are each selected from nitrogen-containing heterocyclic groups, and X and Y are cyclized via a single bond or methylene to form a structure selected from any one of the group consisting of:
<CHM>
<CHM>
or
<CHM>.

In some embodiments, in Formula (<NUM>), Z is selected from
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
or
<CHM>
wherein R<NUM> and R<NUM> are independently selected from hydrogen atom, halogen atoms, nitrile group, C<NUM>-C<NUM> alkyl group, C<NUM>-C<NUM> alkoxy group, C<NUM>-C<NUM> alkanoyl group, C<NUM>-C<NUM> ester group, C<NUM>-C<NUM> sulfonate group, vinyl group, propenyl group, acryloyl group, acrylate group, or methacryloyl group.

In some embodiments, in Formula (<NUM>), n is an integer in a range of <NUM> to <NUM>. In some embodiments, in Formula (<NUM>), n is an integer in a range of <NUM> to <NUM>.

In some embodiments, both the first organic solvent in the first mixture and the second organic solvent in the second mixture are selected from at least one of C<NUM>-C<NUM> alkane, ester, ether, C<NUM>-C<NUM> ketone, or nitrile. In some embodiments, both the first organic solvent in the first mixture and the second organic solvent in the second mixture are selected from at least one of benzene, toluene, xylene, pentane, n-hexane, n-heptane, cyclohexane, methylcyclohexane, ether, diisopropyl ether, methyl tert-butyl ether, tetrahydrofuran, dichloromethane, <NUM>,<NUM>-dioxane, <NUM>,<NUM>-dioxolane, ethyl acetate, isobutyl acetate, tert-butyl acetate, acetone, <NUM>-butanone, <NUM>,<NUM>-dimethyl-<NUM>-butanone, benzonitrile, propionitrile, or acetonitrile. And in some embodiments, both the first organic solvent in the first mixture and the second organic solvent in the second mixture are elected from at least one of tetrahydrofuran, toluene, or ethyl acetate.

In some embodiments, a molar concentration of the phosphorus chloride compound in the first mixture is in a range of <NUM> mol/L to <NUM> mol/L. In some embodiments, a molar concentration of the phosphorus chloride compound in the first mixture is in a range of <NUM> mol/L to <NUM> mol/L.

In some embodiments, a molar concentration of the compound as shown in Formula (<NUM>) of the second mixture is in a range of <NUM> mol/L to <NUM> mol/L. In some embodiments, a molar concentration of the compound as shown in Formula (<NUM>) in the second mixture is in a range of <NUM> mol/L to <NUM> mol/L.

In step S2, in the step of mixing the first mixture with the second mixture in a reaction device to make the first mixture react with the second mixture to obtain a reaction mixture, a reaction temperature is in a range of <NUM> to <NUM> degrees centigrade. In some embodiments, the reaction temperature is in a range of <NUM> degrees centigrade to <NUM> degrees centigrade. In step S2, a reaction time is in a range of <NUM> hour to <NUM> hours. In some embodiments, the reaction time is in a range of <NUM> hours to <NUM> hours. Meanwhile, a molar ratio of the phosphorus chloride compound to the compound as shown in Formula (<NUM>) is controlled to be in a range of <NUM>:(<NUM>/x) to <NUM>:(<NUM>/x), wherein x is equal to n in the compound of Formula (<NUM>), and a molar ratio of nitrogen element in the polypyridine ionic liquid-loaded porous microspheres to a hydroxyl group in the compound as shown in Formula (<NUM>) is controlled to be in a range of <NUM>:<NUM> to <NUM>:<NUM>. In some embodiments, the molar ratio of nitrogen element in the polypyridine ionic liquid-loaded porous microspheres to the hydroxyl group in the compound as shown in Formula (<NUM>) is controlled to be in a range of <NUM>:<NUM> to <NUM>:<NUM>.

In some embodiments, in the step of mixing the first mixture with the second mixture in the reaction device to make the first mixture react with the second mixture to obtain the reaction mixture, the second mixture is added to the first mixture in batches by means of dropwise addition and the like. In some embodiments, the second mixture is continuously and uniformly added dropwise to the first mixture, and an adding duration is controlled in a range of <NUM> hours to <NUM> hours. And in some embodiments, the adding duration is in a range of <NUM> hours to <NUM> hours.

In step S2 of the present disclosure, in a reaction process, hydrogen chloride generated by the reaction is further removed from a reaction device, so as to solve problems of a high viscosity of a system and a difficult post-processing, while improving a selectivity of the reaction and a yield of the reaction.

In some embodiments, the generated hydrogen chloride may be removed from the reaction device by physical methods such as protective gas purging, decompression, ultrasound, etc., and discharged into a hydrogen chloride absorption system to generate hydrochloric acid.

Continuously introducing the protective gas into the reaction device and purging can improve a mixing effect of the reaction. In some embodiments, in step S2, in a step of mixing the first mixture with the second mixture in the reaction device to make the first mixture react with the second mixture, a protective gas is introduced into the reaction device for purging to remove the hydrogen chloride produced by a reaction of the first mixture and the second mixture out from the reaction device.

It can be understood that, any gas that does not affect the reaction can be used as a protective gas. In some embodiments, the protective gas is selected from at least one of nitrogen, argon, neon, helium, carbon monoxide, or carbon dioxide.

In an actual operation, a dry protective gas may be continuously introduced into the reaction device to replace the air and water vapor inside the reaction device, and then the first mixture may be added in the reaction device. Then the second mixture may be dropwise added in the reaction device, and then the second mixture may be added to the first mixture in batches by means of dropwise addition and the like. During the addition, the dry protective gas may be continuously introduced in the reaction device for purging.

After a reaction is completed, a reaction solution is filtered, a filter liquor is firstly concentrated to remove the organic solvent, and a concentrated solution is subjected to a posttreatment, separation and purification to obtain phosphorus-containing ligands. Typically, the phosphorus-containing ligands can be separated and purified by post-processing means such as column chromatography, simulated moving bed, crystallization, extraction, rectification, and the like.

Meanwhile, in a step of filtering the reaction solution, second polypyridine ionic liquid-loaded porous microspheres may be further recovered. In some embodiments, the recovered second polypyridine ionic liquid-loaded porous microspheres may be recycled and re-used in the first mixture in step S1 after washing and drying.

Hereinafter, a method for preparing the phosphorus-containing ligand will be further illustrated in conjunction with the following specific embodiments.

In the following methods for preparing polypyridine ionic liquid-loaded porous microspheres, structural formulas of pyridine monomers are as shown in Formulas N<NUM>-<NUM> to N<NUM>-<NUM>. <CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>.

Methods for preparing polypyridine ionic liquid-loaded porous microspheres D2 to D12 were substantially the same as the method for preparing the polypyridine ionic liquid-loaded porous microspheres D1, except that some reaction parameters in the methods for preparing the polypyridine ionic liquid-loaded porous microspheres D2 to D12 are different from those in the method for preparing the polypyridine ionic liquid-loaded porous microspheres D1. Specific reaction parameters in the methods for preparing the polypyridine ionic liquid-loaded porous microspheres D2 to D12 are shown in Table <NUM>, and reaction results thereof are shown in Table <NUM>.

In the methods for preparing the phosphorus-containing ligands of the following Embodiment <NUM> to Embodiment <NUM>, structural formula of the phosphorus chloride compounds represented by Formula (<NUM>) are shown in Formulas E1 to E12, structural formulas of the compound represented by Formula (<NUM>) were shown as Formulas F1 to F12, and structural formulas of the phosphorus-containing ligands are as shown in Formulas L1 to L <NUM>. <CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>.

Phosphorus chloride compound E1 (<NUM>, <NUM>. 341mol), polypyridine ionic liquid-loaded porous microspheres D1 (<NUM>, containing <NUM> mol of nitrogen element), and toluene were mixed into <NUM> of a first mixture.

<NUM>, <NUM>-dimethyl-<NUM>, <NUM>', <NUM>, <NUM>'-tetrahydroxybiphenyl F1 (<NUM>, <NUM>. 081mol) was mixed with toluene to make <NUM> of a second mixture.

Dry nitrogen gas was continuously fed into a reaction device for <NUM> to replace air and water vapor inside the reaction device. Then the first mixture was transferred to the reaction device, and the second mixture was transferred to a high-level dripping device. A stirrer in the reaction device was started and hydrogen chloride absorption system was operated.

At a temperature of <NUM> degrees centigrade, the second mixture was continuously and uniformly added into the reaction device from the high-level dripping device. An adding time was <NUM> hours, and dry nitrogen was continuously introduced into the reaction device during the dripping process. After the dripping process was completed, reactants in the reaction device were continuously stirred for <NUM> hours. Subsequently, a reaction solution was filtered to remove polypyridine ionic liquid-loaded porous microspheres D1 from the reaction solution to obtain a filter liquor. The filter liquor was concentrated to remove toluene from the filter liquor and obtain a concentrated solution. The concentrated solution was separated and purified by column chromatography to obtain <NUM> of phosphorus-containing ligand L1 with a yield of <NUM>%.

Methods for preparing phosphorus-containing ligands L2 to L12 were the same as the method for preparing the phosphorus-containing ligand L1, except that reaction parameters in the methods for preparing the phosphorus-containing ligands L2 to L12 were different from those in the method for preparing the phosphorus-containing ligand L1. Specific reaction parameters in the methods for preparing the phosphorus-containing ligands L2 to L12 were shown in Table <NUM>, and reaction results thereof were shown in Table <NUM>.

Polypyridine ionic liquid-loaded porous microspheres D1 recycled in Embodiment <NUM> were re-used in experiments for preparing phosphorus-containing ligand L1. Data of the experiments were shown in Table <NUM> below, and specific steps for preparing the phosphorus-containing ligand L1 were the same as those in Embodiment <NUM>.

It can be seen from Table <NUM> that the polypyridine ionic liquid-loaded porous microspheres of the present disclosure can be recycled for many times, and a recovery rate was still greater than <NUM>% and a reactivity was not significantly reduced after <NUM> recycles.

Comparative embodiment <NUM> differed from Embodiment <NUM> only in that the polypyridine ionic liquid-loaded porous microspheres in embodiment <NUM> was replaced with a weak base type macroporous ion exchange resin (<NUM>, model: D301, produced by Chemical Plant of Nankai University). In comparative embodiment <NUM>, after a reaction was completed, <NUM> of phosphorus-containing ligand L1 was can be obtained by separation and purification, with a selectivity of <NUM>% and a yield of <NUM>%.

Comparative embodiment <NUM> differed from Embodiment <NUM> only in that the polypyridine ionic liquid-loaded porous microspheres in Embodiment <NUM> was replaced with <NUM> of anhydrous triethylamine, and the reaction in comparative embodiment <NUM> was carried out without continuous introduction of dry nitrogen or operation of hydrogen chloride absorption system. In comparative embodiment <NUM>, after the reaction was completed, <NUM> of phosphate-containing ligand L1 was obtained by separation and purification, with a selectivity of <NUM>% and a yield of <NUM>%.

In preparation methods of the present disclosure, polypyridine ionic liquid-loaded porous microspheres were used as catalysts, and porous structures of the polypyridine ionic liquid-loaded porous microspheres can increase catalytic active sites of a reaction, thereby improving a selectivity and a yield of the reaction. Meanwhile, a catalytic effect can reduce an activation energy required for the reaction. Specifically, due to the catalytic effect, a reaction temperature can be reduced, and a chemical reaction rate can be speed up, which is more suitable for preparing phosphorus-containing ligands containing sensitive groups (such as double bonds, etc.). Moreover, the catalysts in the present disclosure have stable properties, simple post-treatments, good recycling performances, and thus they are easy to be recovered and reused.

In the present disclosure, in a reaction process, hydrogen chloride generated by the reaction is removed from a reaction device, so as to solve problems of a high viscosity of a system and a difficult post-processing, thus improving a selectivity and a yield of the reaction.

Claim 1:
A method for preparing a phosphorus-containing ligand, comprising:
mixing a phosphorus chloride compound as shown in Formula (<NUM>), first polypyridine ionic liquid-loaded porous microspheres with a first organic solvent to obtain a first mixture, and mixing a compound as shown in Formula (<NUM>) with a second organic solvent to obtain a second mixture; and
mixing the first mixture with the second mixture in a reaction device to make the first mixture react with the second mixture to obtain a reaction mixture, removing generated hydrogen chloride from the reaction device, filtrating the reaction mixture to obtain a filter liquor after a reaction of the first mixture and the second mixture, and treating the filter liquor to obtain the phosphorus-containing ligand,
<CHM>
wherein in Formula (<NUM>), X and Y are independently selected from substituted aryloxy groups or nitrogen-containing heterocyclic groups,
in Formula (<NUM>), Z is a multivalent aliphatic hydrocarbon group or a multivalent aromatic hydrocarbon group comprising at least one substituent group,
wherein the at least one substituent group is selected from hydrogen atom, halogen atoms, C<NUM>-C<NUM> alkyl group, C<NUM>-C<NUM> alkoxy group, C<NUM>-C<NUM> alkanoyl group, aryl group, heteroaryl group, cyano group, or nitro group, and n is an integer in a range of <NUM> to <NUM>.