Nitrile rubber hydrogenation method, hydrogenated nitrile rubber and application

Abstract

The invention relates to the field of unsaturated copolymer hydrogenation, and discloses a nitrile rubber hydrogenation method, hydrogenated nitrile rubber and application. Comprising the following steps: a, hydrogenation reaction: in the presence of hydrogen, contacting a polyethylene glycol stabilized nano rhodium catalyst with a nitrile rubber solution for hydrogenation reaction; b, recovering the catalyst: after the hydrogenation reaction is finished, reducing pressure and temperature, adding a first solvent, carrying out first stirring, continuously cooling to normal temperature, and then carrying out phase splitting to obtain the recovered catalyst; recycling the recovered catalyst in the step b to the step a for reuse; the solid content of the nitrile rubber solution is 1-15 wt%; after cooling and adding the first solvent, the temperature of the system is 65-75 DEG C. The method is green and environment-friendly, when the polyethylene glycol stabilized nano rhodium catalyst is used in nitrile rubber hydrogenation, the catalytic activity is high, the catalyst has good recyclability, and the separation of the catalyst can be realized through simple phase separation operation.

Description

Technical Field

[0001] The invention relates to the field of unsaturated copolymer hydrogenation, and in particular to a method for hydrogenating nitrile rubber, hydrogenated nitrile rubber and application. Background Art

[0002] Hydrogenated nitrile rubber has good properties such as wear resistance, low temperature resistance (-40℃), oxidation resistance, ozone resistance and thermal stability. It can be used to manufacture parts of automobile fuel systems, oil field blowout preventers, seals for nuclear power plants and printing and dyeing rubber rollers, etc. It is currently mainly produced through hydrogenation modification of nitrile rubber.

[0003] At present, most hydrogenated nitrile products on the market are produced by homogeneous solution hydrogenation. The catalyst is dispersed in the polymer solution in molecular form, and the degree of hydrogenation can easily meet the standard. However, this method generally uses expensive precious metal coordination compounds as catalysts. The amount of precious metal residues in the hydrogenation product is large, and it is difficult to separate the catalyst and the hydrogenation product. If the catalyst remains in the rubber product, on the one hand, it seriously affects its aging performance, and on the other hand, it also increases the production cost. Summary of the invention

[0004] The purpose of the present invention is to overcome the problems of high catalyst cost, large residual amount, difficult separation and the like in the prior art, and to provide a method for hydrogenating nitrile rubber, hydrogenated nitrile rubber and application. The nano rhodium catalyst for hydrogenating nitrile rubber has high catalytic activity, and the catalyst can be separated and recycled by a simple phase separation operation.

[0005] In order to achieve the above object, the present invention provides a method for hydrogenating nitrile rubber in a first aspect, characterized in that it comprises the following steps:

[0006] a. Hydrogenation reaction: In the presence of hydrogen, the polyethylene glycol-stabilized nano-rhodium catalyst is brought into contact with the nitrile rubber solution to carry out a hydrogenation reaction;

[0007] b. Recovering the catalyst: After the hydrogenation reaction is completed, the pressure and temperature are lowered, a first solvent is added, and a first stirring is performed. After cooling to room temperature, the phases are separated to obtain a recovered catalyst;

[0008] The recovered catalyst in step b is recycled to step a for reuse;

[0009] The solid content of the nitrile rubber solution is 1-15wt%;

[0010] After cooling and adding the first solvent, the system temperature is made to be 65-75°C.

[0011] The second aspect of the present invention provides a hydrogenated nitrile rubber, characterized in that it is prepared by the method provided by the first aspect of the present invention;

[0012] When the polyethylene glycol-stabilized nano-rhodium catalyst is used once, the hydrogenation degree of the hydrogenated nitrile rubber is not less than 82%, and the residual amount of rhodium in the hydrogenated nitrile rubber is not more than 1 ppm.

[0013] According to one embodiment of the present invention, when the polyethylene glycol-stabilized nano-rhodium catalyst is used 5 times, the degree of hydrogenation of the hydrogenated nitrile rubber is not less than 82%, and the residual amount of rhodium in the hydrogenated nitrile rubber is not more than 5 ppm.

[0014] According to one embodiment of the present invention, when the polyethylene glycol-stabilized nano-rhodium catalyst is used 10 times, the degree of hydrogenation of the hydrogenated nitrile rubber is not less than 82%, and the residual amount of rhodium in the hydrogenated nitrile rubber is not more than 10 ppm.

[0015] The third aspect of the present invention provides an application of the hydrogenated nitrile rubber described in the second aspect of the present invention in at least one of the fields of aerospace, oil fields, transportation and deep sea.

[0016] Through the above technical scheme, the method for hydrogenating nitrile rubber, hydrogenated nitrile rubber and application provided by the present invention obtain the following beneficial effects: in the method for hydrogenating nitrile rubber provided by the present invention, by using a nano rhodium catalyst and using polyethylene glycol as the mobile phase of the catalyst, the active component nano rhodium is dynamically loaded therein, so that the hydrogenation catalytic activity is high, and the catalyst has good recycling regeneration and can be stably applied to the hydrogenation reaction of nitrile rubber. In addition, the nano rhodium catalyst can be separated from the hydrogenated nitrile rubber solution by simple phase separation, and the catalyst loss rate is low. DETAILED DESCRIPTION

[0017] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0018] A first aspect of the present invention provides a method for hydrogenating nitrile rubber, characterized in that it comprises the following steps:

[0019] a. Hydrogenation reaction: In the presence of hydrogen, the polyethylene glycol-stabilized nano-rhodium catalyst is brought into contact with the nitrile rubber solution to carry out a hydrogenation reaction;

[0020] c. Recovering the catalyst: After the hydrogenation reaction is completed, the pressure and temperature are lowered, a first solvent is added, and a first stirring is performed. After cooling to room temperature, phase separation is performed to obtain a recovered catalyst;

[0021] The recovered catalyst in step b is recycled to step a for reuse;

[0022] The solid content of the nitrile rubber solution is 1-15wt%;

[0023] After cooling and adding the first solvent, the system temperature is made to be 65-75°C.

[0024] In the present invention, polyethylene glycol is used as the mobile phase of the catalyst, and the active component nano-rhodium is dynamically loaded therein, so the catalytic activity is high and the catalyst has good cyclic regeneration performance.

[0025] In the nitrile rubber solution, when the solid content of the nitrile rubber solution meets the above range, its viscosity is more suitable for hydrogenation, and the degree of hydrogenation is further improved.

[0026] In the present invention, the conditions for the first stirring are not particularly limited. For example, in the present invention, the stirring may be performed at 70-90° C. for 1-12 h.

[0027] In the present invention, the hydrogenation reaction described in step a is preferably carried out under the fourth stirring. In order to obtain better technical effects, the rate of the fourth stirring is 20-600 rpm, preferably 50-400 rpm.

[0028] In the present invention, the first solvent is selected from at least one of n-heptane, cyclohexane, diethyl ether and isopropyl ether.

[0029] In the present invention, after the first stirring, the system is preferably cooled to room temperature (20-25° C.) before phase separation.

[0030] In the present invention, during the hydrogenation reaction, the ethylene glycol phase and the nitrile rubber solution are mixed into one phase, the nano rhodium catalyst is uniformly dispersed in the system, and the hydrogenation reaction can be carried out efficiently; after the reaction is completed, the first solvent is added, and the system temperature is controlled to separate the polyethylene glycol-stabilized nano rhodium catalyst and the nitrile rubber solution into two liquid-liquid phases that are immiscible with each other, and the active component nano rhodium returns from the organic solvent phase to the polyethylene glycol phase. After the system continues to cool to room temperature, the catalyst can be separated and recycled through a simple phase separation operation.

[0031] In the present invention, there is no particular limitation on the phase separation operation, which may be a conventional phase separation operation in the art, and those skilled in the art may adjust it as needed, for example, it may be filtration.

[0032] According to the present invention, the number average molecular weight of the polyethylene glycol is 400-10000.

[0033] In the present invention, when the number average molecular weight of the polyethylene glycol meets the above range, the viscosity is appropriate, and the active component nano-rhodium can be well dispersed therein, thereby further improving the catalytic activity.

[0034] According to the present invention, the number average molecular weight of the polyethylene glycol is 1000-5000.

[0035] According to the present invention, the particle size of the polyethylene glycol-stabilized nano-rhodium catalyst is 1-10 nm.

[0036] In the present invention, when the particle size of the polyethylene glycol-stabilized nano-rhodium catalyst meets the above range, when applied to the hydrogenation reaction of nitrile rubber, the catalyst can be uniformly dispersed in the reaction system, thereby improving the catalytic activity and catalytic efficiency.

[0037] According to the present invention, the particle size of the polyethylene glycol-stabilized nano-rhodium catalyst is 1-5 nm.

[0038] According to the present invention, based on the total amount of the polyethylene glycol-stabilized nano-rhodium catalyst, the content of rhodium element is 10-280 ppm.

[0039] In the present invention, when the content of the rhodium element meets the above range, the cost can be reduced while ensuring the catalytic activity.

[0040] According to the present invention, based on the total amount of the polyethylene glycol-stabilized nano-rhodium catalyst, the content of rhodium element is 25-160 ppm.

[0041] In the present invention, the method further comprises: after the fourth stirring is completed, cooling and reducing the pressure so that the temperature of the system is room temperature (20-25° C.) and the pressure is normal pressure.

[0042] According to the present invention, the nitrile rubber solution contains a second solvent and nitrile rubber.

[0043] In the present invention, the nitrile rubber solution is obtained by dissolving the nitrile rubber in a second solvent.

[0044] Furthermore, the second solvent is an organic solvent, selected from at least one of aromatic hydrocarbons, derivatives of aromatic hydrocarbons substituted by alkyl or halogen, halogenated alkanes, ethers, ketones and amides, preferably at least one of benzene, toluene, xylene, chlorobenzene, dichlorobenzene, trichlorobenzene, dichloromethane, chloroform, 1,2-dichloroethane, tetrahydrofuran, acetone, butanone and N,N-dimethylformamide.

[0045] In the present invention, when preparing the nitrile rubber solution, it is preferably carried out in the presence of a protective gas.

[0046] According to the present invention, the solid content of the nitrile rubber solution is 3-10wt%.

[0047] According to the present invention, the content of rhodium element in the polyethylene glycol-stabilized nano-rhodium catalyst is 0.01-0.5wt% of the nitrile rubber.

[0048] In the present invention, the content of rhodium element in the polyethylene glycol-stabilized nano-rhodium catalyst is 0.01-0.5wt% of the nitrile rubber, which can make the hydrogenation reaction of the nitrile rubber efficient and economical.

[0049] According to the present invention, the content of rhodium element in the polyethylene glycol-stabilized nano-rhodium catalyst is 0.03-0.1wt% of the nitrile rubber.

[0050] According to the present invention, the conditions of the hydrogenation reaction include: pressure 1-10 MPa, temperature 70-150° C., and time 1-18 h.

[0051] In the present invention, when the conditions of the hydrogenation reaction meet the above range, the hydrogenation reaction of the nitrile rubber is stable and efficient under the action of the nano-rhodium catalyst stabilized by polyethylene glycol.

[0052] According to the present invention, the conditions of the hydrogenation reaction include: pressure 3-8 MPa, temperature 80-150° C., and time 4-12 h.

[0053] According to the present invention, the first stirring conditions include: stirring time of 1-3h; stirring temperature of 65-75°C.

[0054] In the present invention, there is no particular limitation on the stirring rate of the first stirring, as long as the particle size of the rhodium salt can meet the requirements. For example, the stirring rate in the present invention can be 50-400 rpm.

[0055] In the present invention, when the system temperature meets the above range during the first stirring, efficient separation of the organic solvent phase and the ethylene glycol phase can be achieved, and the polyethylene glycol-stabilized nano-rhodium catalyst can be efficiently separated, and the residual amount of rhodium catalyst in the hydrogenated nitrile rubber is low.

[0056] According to the present invention, the mass ratio of the first solvent, polyethylene glycol and the second solvent is 1:0.4-3:1-7.

[0057] In the present invention, the inventors found that the types of the first solvent and the second solvent have a great influence on the temperature at which the second solvent and the ethylene glycol phase achieve liquid-liquid separation, and it is necessary to ensure that the temperature at which the second solvent and the polyethylene glycol phase achieve liquid-liquid separation is not lower than 75°C.

[0058] According to the present invention, the method for preparing the polyethylene glycol-stabilized nano-rhodium catalyst comprises the following steps:

[0059] S1, stirring the rhodium salt and polyethylene glycol for a second time to obtain a mixture;

[0060] S2, in the absence of oxygen, introducing hydrogen into the mixture to pressurize it, and performing a third stirring to obtain a polyethylene glycol-stabilized nano-rhodium catalyst;

[0061] In the mixture, the mass ratio of the rhodium salt to the polyethylene glycol is 0.00001-0.00028:1, calculated on the basis of rhodium.

[0062] In the present invention, the preparation method is simple to operate, green and environmentally friendly, and the prepared polyethylene glycol-stabilized nano-rhodium catalyst has a small particle size and good repeatability.

[0063] In the present invention, the introduction of hydrogen gas and pressurization to the above range can efficiently reduce rhodium ions to zero-valent rhodium, thereby obtaining a polyethylene glycol-stabilized nano-rhodium catalyst with high catalytic efficiency.

[0064] In the present invention, in step S2, there are no special requirements and limitations on the conditions and methods for creating anaerobic conditions. For example, in the present invention, the system can be replaced by a protective gas. Preferably, the protective gas can be nitrogen and / or an inert gas.

[0065] Furthermore, in the mixture, when the mass ratio of the rhodium salt to the polyethylene glycol, calculated on the basis of rhodium, satisfies the above range, the rhodium salt has good dispersibility in the polyethylene glycol and high catalytic activity.

[0066] Furthermore, in order to obtain better technical effects, after the system is replaced with the protective gas, hydrogen may be introduced for replacement again.

[0067] In the present invention, the inventors have found that when the above-mentioned rhodium salt is selected from rhodium chloride, the generated catalyst has stable performance, which is beneficial to improving the hydrogenation efficiency.

[0068] Furthermore, in the present invention, the rhodium salt is preferably added in the form of a rhodium salt aqueous solution.

[0069] According to the present invention, the second stirring condition includes: stirring at 70-90° C. for 1-3 hours.

[0070] In the present invention, the second stirring condition satisfies the above range, which can make the rhodium salt better dispersed in the polyethylene glycol, improve its dispersibility and thus improve the hydrogenation efficiency.

[0071] In the present invention, there is no particular limitation on the stirring rate of the second stirring, as long as the rhodium salt can be evenly dispersed in the polyethylene glycol. For example, in the present invention, the stirring rate of the second stirring is 200-500 rpm.

[0072] According to the present invention, the third stirring condition includes stirring at 70-90° C. for 4-10 h.

[0073] In the present invention, there is no particular limitation on the stirring rate of the third stirring, as long as the rhodium ions can be efficiently reduced. For example, in the present invention, the stirring rate of the third stirring is 200-500 rpm.

[0074] According to the present invention, in the mixture, the mass ratio of the rhodium salt to the polyethylene glycol is 0.000025-0.00016:1, calculated on the basis of rhodium.

[0075] In the present invention, in the step S2, the pressurization is performed so that the system pressure is 3-6 MPa.

[0076] The second aspect of the present invention provides a hydrogenated nitrile rubber, characterized in that it is prepared by the method provided by the first aspect of the present invention;

[0077] Wherein, when the polyethylene glycol-stabilized nano-rhodium catalyst is used once, the hydrogenation degree of the hydrogenated nitrile rubber is not less than 82%, and the residual rhodium content in the hydrogenated nitrile rubber is not more than 1 ppm;

[0078] Alternatively, when the polyethylene glycol-stabilized nano-rhodium catalyst is used 5 times, the degree of hydrogenation of the hydrogenated nitrile rubber is not less than 82%, and the residual amount of rhodium in the hydrogenated nitrile rubber is not more than 5 ppm;

[0079] Alternatively, when the polyethylene glycol-stabilized nano-rhodium catalyst is used 10 times, the degree of hydrogenation of the hydrogenated nitrile rubber is not less than 82%, and the residual amount of rhodium in the hydrogenated nitrile rubber is not more than 10 ppm.

[0080] The third aspect of the present invention provides an application of the hydrogenated nitrile rubber described in the second aspect of the present invention in at least one of the fields of aerospace, oil fields, transportation and deep sea.

[0081] The present invention will be described in detail below through preparation examples and examples.

[0082] In the following examples, the degree of hydrogenation was measured by HNMR;

[0083] The residual rhodium in hydrogenated nitrile rubber was measured by ICP-OES inductively coupled plasma atomic emission spectrometry;

[0084] The particle size of the polyethylene glycol-stabilized nanorhodium catalyst was measured by TEM;

[0085] In the preparation example, nitrile rubber was purchased from PetroChina Lanzhou Petrochemical Company, brand 4105;

[0086] Polyethylene glycol, molecular weight 1000, 2000, 4000, 10000, 20000, purchased from Alfa Aesar;

[0087] RhCl3·3H2O, purchased from Kunming Borui Metal Materials Co., Ltd.;

[0088] Polyvinyl alcohol, molecular weight 20,000, purchased from Alfa Aesar;

[0089] Na2PdCl4·xH2O (containing 30wt% Pd), purity 99%, was purchased from Alfa Aesar.

[0090] Other reagents were commercially available analytical grade drugs.

[0091] The following preparation example is used to describe the preparation of polyethylene glycol-stabilized nano-rhodium catalyst.

[0092] Preparation Example 1

[0093] S1. Add 0.7 g of RhCl3 aqueous solution (containing 0.24 mmol of RhCl3·3H2O) and 263 g of polyethylene glycol 4000 into a reaction kettle, stir for 2 h at 90° C. and a stirring rate of 300 r / min to obtain a mixture, wherein the mass ratio of rhodium salt to polyethylene glycol 4000 is 0.000095:1 in terms of rhodium;

[0094] S2. After replacing the mixture in the reactor with nitrogen and hydrogen respectively, the reactor was pressurized to 4 MPa with hydrogen, stirred at 70° C. and a stirring rate of 300 r / min for 2 h, cooled to 20° C., and reduced to normal pressure to obtain polyethylene glycol-stabilized nano-rhodium catalyst A1.

[0095] The particle size and rhodium content of the polyethylene glycol-stabilized nano-rhodium catalyst A1 are shown in Table 1.

[0096] Preparation Example 2

[0097] S1. Add 1.4 g of RhCl3 aqueous solution (containing 0.49 mmol of RhCl3·3H2O) and 2000 g of polyethylene glycol 2000 into a reaction kettle, and stir for 4 h at 70° C. and a stirring rate of 300 r / min to obtain a mixture, wherein the mass ratio of rhodium to polyethylene glycol 2000 is 0.000025:1 in terms of rhodium;

[0098] S2. After replacing the mixture in the reactor with nitrogen and hydrogen respectively, the reactor was pressurized to 4 MPa with hydrogen, stirred at 90° C. and a stirring rate of 300 r / min for 2 h, cooled to 20° C., and reduced to normal pressure to obtain polyethylene glycol-stabilized nano-rhodium catalyst A2.

[0099] The particle size and rhodium content of the polyethylene glycol-stabilized nano-rhodium catalyst A2 are shown in Table 1.

[0100] Preparation Example 3

[0101] S1. Add 0.4 g of RhCl3 aqueous solution (containing 0.15 mmol of RhCl3·3H2O) and 94 g of polyethylene glycol 1000 into a reaction kettle, stir for 4 h at 70° C. and a stirring rate of 300 r / min to obtain a mixture, wherein the mass ratio of rhodium to polyethylene glycol 1000 is 0.00016:1 in terms of rhodium;

[0102] S2. After replacing the mixture in the reactor with nitrogen and hydrogen respectively, the reactor was pressurized to 2 MPa with hydrogen, stirred at 90° C. and a stirring rate of 300 r / min for 4 h, cooled to 20° C., and reduced to normal pressure to obtain polyethylene glycol-stabilized nano-rhodium catalyst A3.

[0103] The particle size and rhodium content of the polyethylene glycol-stabilized nano-rhodium catalyst A3 are shown in Table 1.

[0104] Preparation Example 4

[0105] The method is consistent with that of Preparation Example 1, except that the amount of polyethylene glycol 4000 used is 118 g, and in the obtained mixture, the mass ratio of rhodium to polyethylene glycol 4000 is 0.000212:1, calculated as rhodium;

[0106] The particle size and rhodium content of the polyethylene glycol-stabilized nano-rhodium catalyst A4 are shown in Table 1.

[0107] Preparation Example 5

[0108] The method is consistent with that of Preparation Example 1, except that the amount of polyethylene glycol 4000 used is 60 g, and in the obtained mixture, the mass ratio of rhodium to polyethylene glycol 4000 is 0.000411:1, calculated as rhodium;

[0109] The particle size and rhodium content of the polyethylene glycol-stabilized nano-rhodium catalyst A5 are shown in Table 1.

[0110] Preparation Example 6

[0111] The method was consistent with that of Preparation Example 1, except that the stirring was carried out at 25°C for 10 h.

[0112] The particle size and rhodium content of the polyethylene glycol-stabilized nano-rhodium catalyst A6 are shown in Table 1.

[0113] Preparation Example 7

[0114] The method is consistent with that of Preparation Example 1, except that polyethylene glycol 4000 is replaced by polyethylene glycol 10000;

[0115] The particle size and rhodium content of the obtained polyethylene glycol-stabilized nano-rhodium catalyst A7 are shown in Table 1.

[0116] Preparation Example 8

[0117] The method is consistent with the method of Preparation Example 1, except that polyethylene glycol 4000 is replaced by polyethylene glycol 20000;

[0118] The particle size and rhodium content of the obtained polyethylene glycol-stabilized nano-rhodium catalyst A8 are shown in Table 1.

[0119] Comparative Preparation Example 1

[0120] The method is consistent with that of Preparation Example 1, except that polyethylene glycol 4000 is replaced by polyvinyl alcohol (molecular weight 20000);

[0121] The particle size and rhodium content of the obtained polyvinyl alcohol-stabilized nano-rhodium catalyst D1 are shown in Table 1.

[0122] Comparative Preparation Example 2

[0123] The method is consistent with that of Preparation 1, except that the aqueous solution of RhCl3 is replaced by an aqueous solution of Na2PdCl4;

[0124] The particle size and palladium content of the obtained polyethylene glycol-stabilized nano-palladium catalyst D2 are shown in Table 1.

[0125] Comparative Preparation Example 3

[0126] The method is consistent with that of Preparation Example 1, except that the nanometer-scale rhodium metal particles obtained by physical grinding are dispersed in polyethylene glycol-4000. The particle size and rhodium content of the obtained polyethylene glycol-stabilized nanorhodium catalyst D3 are shown in Table 1.

[0127] Table 1

[0128] catalyst Average particle size / nm Rhodium / palladium content / ppm A1 2.2 95 A2 1.3 25 A3 3.5 160 A4 5.4 212 A5 9.2 275 A6 8.6 94 A7 5.9 95 A8 9.8 93 D1 15 5 D2 25 94 D3 58.9 94

[0129] It can be seen from Table 1 that the average particle size of Preparation Examples 1-8 is between 1-10 nm, and the rhodium content is 10-280 ppm. Among them, the average particle size of the preferred embodiments 1-3 is within the range of 1-5 nm, and the rhodium content is within the range of 25-160 ppm.

[0130] The following examples and comparative examples are used to describe the method of hydrogenating nitrile rubber and recovering catalyst. Among them, the solid content of the nitrile rubber solution refers to the percentage of the mass of the nitrile rubber to the mass of the nitrile rubber solution; the amount of rhodium nano catalyst refers to the percentage of the mass of rhodium in the catalyst to the mass of the nitrile rubber; the residual rhodium in the hydrogenated nitrile rubber refers to the percentage of the mass of the rhodium element in the hydrogenated nitrile rubber to the mass of the nitrile rubber.

[0131] Example 1

[0132] a. Hydrogenation reaction: Under the protection of nitrogen, 50 g of nitrile rubber was dissolved in 950 g of toluene solution to obtain a nitrile rubber solution, to which a polyethylene glycol-stabilized nano-rhodium catalyst A1 was added, and the mixture was reacted for 12 h at a hydrogen pressure of 8 MPa, a system temperature of 80° C., and a stirring rate of 100 rpm to obtain a hydrogenated nitrile rubber solution;

[0133] b. The pressure was reduced to normal pressure, and 315 g of n-heptane (50° C.) was added to the reactor. At this time, the system temperature was 70° C., and the mixture was stirred at 100 rpm and 70° C. (first stirring) for 2 h. The mixture was then cooled to room temperature and the catalyst A1 was recovered by phase separation. The hydrogenation conditions and the first stirring conditions are detailed in Table 2.

[0134] Among them, the mass ratio of n-heptane, polyethylene glycol and toluene is 1:0.8:3. The solid content of the nitrile rubber solution, the amount of rhodium nanocatalyst, the degree of hydrogenation and the residual rhodium in the hydrogenated nitrile rubber are shown in Table 3.

[0135] Example 2

[0136] The method is consistent with that of Example 1, except that:

[0137] (1) Replace A1 with A2;

[0138] (2) The conditions of the hydrogenation reaction are: 130°C, 3 MPa, 100 rpm, 7 h;

[0139] (3) When recovering the catalyst, the system temperature was lowered to 105°C, and 539 g of n-heptane (25°C) was added to the reactor. At this time, the system temperature was 70°C, and the mixture was stirred at 200 rpm and 70°C for 1 hour.

[0140] Among them, the mass ratio of n-heptane, polyethylene glycol and toluene is 1:0.48:1.76.

[0141] The hydrogenation conditions and the first stirring conditions are shown in Table 2. The solid content of the nitrile rubber solution, the amount of rhodium nanocatalyst, the degree of hydrogenation and the residual rhodium in the hydrogenated nitrile rubber are shown in Table 3.

[0142] Example 3

[0143] The method is consistent with that of Example 1, except that:

[0144] (1) Replace A1 with A3;

[0145] (2) The conditions of the hydrogenation reaction are: 120°C, 5 MPa, 300 rpm, 7 h;

[0146] (3) When recovering the catalyst, the system temperature was lowered to 80°C, and 150 g of n-heptane (25°C) was added to the reactor. At this time, the system temperature was 70°C. The mixture was stirred at 400 rpm and 70°C for 1 h. The mass ratio of n-heptane, polyethylene glycol and toluene was 1:1.75:6.3.

[0147] The hydrogenation conditions and the first stirring conditions are shown in Table 2. The solid content of the nitrile rubber solution, the amount of rhodium nanocatalyst, the degree of hydrogenation, and the residual rhodium in the hydrogenated nitrile rubber are shown in Table 3.

[0148] Embodiment 4-8

[0149] The same as Example 1, except that A1 is replaced by A4-A9.

[0150] The hydrogenation conditions and the first stirring conditions are shown in Table 2. The solid content of the nitrile rubber solution, the amount of rhodium nanocatalyst, the degree of hydrogenation, and the residual rhodium in the hydrogenated nitrile rubber are shown in Table 3.

[0151] Example 9

[0152] The same as Example 1, except that the conditions of the hydrogenation reaction are: 75° C. for 24 hours under a hydrogen pressure of 8 MPa.

[0153] The hydrogenation conditions and the first stirring conditions are shown in Table 2. The solid content of the nitrile rubber solution, the amount of rhodium nanocatalyst, the degree of hydrogenation, and the residual rhodium in the hydrogenated nitrile rubber are shown in Table 3.

[0154] Example 10

[0155] The method is consistent with that of Example 1, except that A1 is reused 5 times.

[0156] The hydrogenation conditions and the first stirring conditions are shown in Table 2. The solid content of the nitrile rubber solution, the amount of rhodium nanocatalyst, the degree of hydrogenation, and the residual rhodium in the hydrogenated nitrile rubber are shown in Table 3.

[0157] Embodiment 11

[0158] The method is consistent with that of Example 1, except that A1 is reused 10 times.

[0159] The hydrogenation conditions and the first stirring conditions are shown in Table 2. The solid content of the nitrile rubber solution, the amount of rhodium nanocatalyst, the degree of hydrogenation, and the residual rhodium in the hydrogenated nitrile rubber are shown in Table 3.

[0160] Example 12

[0161] The method is consistent with that of Example 2, except that A2 is reused 5 times.

[0162] The hydrogenation conditions and the first stirring conditions are shown in Table 2. The solid content of the nitrile rubber solution, the amount of rhodium nanocatalyst, the degree of hydrogenation, and the residual rhodium in the hydrogenated nitrile rubber are shown in Table 3.

[0163] Embodiment 13

[0164] The method is consistent with that of Example 2, except that A2 is reused 10 times.

[0165] The hydrogenation conditions and the first stirring conditions are shown in Table 2. The solid content of the nitrile rubber solution, the amount of rhodium nanocatalyst, the degree of hydrogenation, and the residual rhodium in the hydrogenated nitrile rubber are shown in Table 3.

[0166] Embodiment 14

[0167] The method is consistent with that of Example 3, except that A3 is reused 5 times.

[0168] The hydrogenation conditions and the first stirring conditions are shown in Table 2. The solid content of the nitrile rubber solution, the amount of rhodium nanocatalyst, the degree of hydrogenation, and the residual rhodium in the hydrogenated nitrile rubber are shown in Table 3.

[0169] Embodiment 15

[0170] The method is consistent with that of Example 3, except that A3 is reused 10 times.

[0171] The hydrogenation conditions and the first stirring conditions are shown in Table 2. The solid content of the nitrile rubber solution, the amount of rhodium nanocatalyst, the degree of hydrogenation, and the residual rhodium in the hydrogenated nitrile rubber are shown in Table 3.

[0172] Comparative Examples 1-3

[0173] The method is consistent with that of Example 1, except that A1 is replaced by D1-D3.

[0174] The hydrogenation conditions and the first stirring conditions are shown in Table 2. The solid content of the nitrile rubber solution, the amount of rhodium nanocatalyst, the degree of hydrogenation, and the residual rhodium in the hydrogenated nitrile rubber are shown in Table 3.

[0175] Comparative Example 4

[0176] The same as Example 1, except that the amount of nitrile rubber used is 5g, and the amount of toluene used is 950g.

[0177] The hydrogenation conditions and the first stirring conditions are shown in Table 2. The solid content of the nitrile rubber solution, the amount of rhodium nanocatalyst, the degree of hydrogenation, and the residual rhodium in the hydrogenated nitrile rubber are shown in Table 3.

[0178] Comparative Example 5

[0179] The same as Example 1, except that when recovering the catalyst, after the system temperature was reduced to 60°C, 315g of n-heptane (25°C) was added to the reactor. At this time, the system temperature was 50°C, and stirring was carried out at 100rpm and 50°C (first stirring) for 2h.

[0180] The hydrogenation conditions and the first stirring conditions are shown in Table 2. The solid content of the nitrile rubber solution, the amount of rhodium nanocatalyst, the degree of hydrogenation, and the residual rhodium in the hydrogenated nitrile rubber are shown in Table 3.

[0181] Comparative Example 6

[0182] The same as Example 1, except that when recovering the catalyst, no n-heptane was added, and the system temperature was directly lowered to room temperature (25° C.), and then stirred at 100 rpm and 25° C. (first stirring) for 2 h.

[0183] The hydrogenation conditions and the first stirring conditions are shown in Table 2. The solid content of the nitrile rubber solution, the amount of rhodium nanocatalyst, the degree of hydrogenation, and the residual rhodium in the hydrogenated nitrile rubber are shown in Table 3.

[0184] Table 2

[0185]

[0186]

[0187] * Refers to the first stirring in step b

[0188] Table 3

[0189]

[0190]

[0191] It can be seen from the above results that Examples 1-15 of the present invention have better effects, wherein the degree of hydrogenation is above 50% and the residual rhodium content does not exceed 60 ppm.

[0192] Among them, Examples 1-4, 7, 9 and 11 have further effects, with the degree of hydrogenation being above 70% and the residual rhodium content being no more than 13 ppm.

[0193] Furthermore, Examples 1-3 that conform to the preferred technical solution of the present invention have significantly better effects, with the degree of hydrogenation being above 82% and the residual rhodium content not exceeding 0.5 ppm.

[0194] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for hydrogenating nitrile rubber, characterized in that, The following steps are involved: a. Hydrogenation reaction: In the presence of hydrogen, the polyethylene glycol-stabilized nano-rhodium catalyst is brought into contact with the nitrile rubber solution to carry out a hydrogenation reaction; b. Recovering the catalyst: After the hydrogenation reaction is completed, the pressure and temperature are lowered, a first solvent is added, and a first stirring is performed. After cooling to room temperature, the phases are separated to obtain a recovered catalyst; The recovered catalyst in step b is recycled to step a for reuse; The solid content of the nitrile rubber solution is 1-15wt%; After cooling and adding the first solvent, the system temperature is made to be 65-75°C.

2. The method for hydrogenating acrylonitrile-butadiene rubber according to claim 1, wherein The number average molecular weight of the polyethylene glycol is 400-10000, preferably 1000-5000.

3. The method for hydrogenating acrylonitrile-butadiene rubber according to claim 1 or 2, wherein The particle size of the polyethylene glycol-stabilized nano-rhodium catalyst is 1-10 nm, preferably 1-5 nm.

4. according to the method for hydrogenation of any one of the acrylonitrile-butadiene rubbers in the claim 1-3, wherein, Based on the total amount of the polyethylene glycol-stabilized nano-rhodium catalyst, the content of rhodium element is 10-280 ppm, preferably 25-160 ppm.

5. according to the method for hydrogenation of any one of the acrylonitrile-butadiene rubbers in the claim 1-4, wherein, The nitrile rubber solution contains a second solvent and nitrile rubber; Preferably, the solid content of the nitrile rubber solution is 3-10wt%.

6. according to the method for hydrogenation of any one of the acrylonitrile-butadiene rubbers in the claim 1-5, wherein, The amount of the polyethylene glycol-stabilized nano-rhodium catalyst and the nitrile rubber solution is such that the content of rhodium element is 0.01-0.5wt% of the nitrile rubber, preferably 0.03-0.1wt%.

7. according to the method for hydrogenation of any one of the acrylonitrile-butadiene rubbers in the claim 1-6, wherein, The conditions of the hydrogenation reaction include: pressure 1-10 MPa, preferably 3-8 MPa, temperature 75-150° C., preferably 80-130° C., time 1-18 h, preferably 4-12 h.

8. according to the method for hydrogenation of any one of the acrylonitrile-butadiene rubbers in the claim 1-7, wherein, The depressurization makes the system pressure normal pressure; Preferably, the first stirring conditions include: stirring time of 1-3h; stirring temperature of 65-75°C.

9. The method for hydrogenating acrylonitrile-butadiene rubber according to claim 7 or 8, wherein The mass ratio of the first solvent, the polyethylene glycol and the second solvent is 1:0.4-3:1-7.

10. A method for hydrogenating acrylonitrile-butadiene rubber according to any one of claims 1 to 9, wherein The preparation method of the polyethylene glycol-stabilized nano-rhodium catalyst comprises the following steps: S1, stirring the rhodium salt and polyethylene glycol for a second time to obtain a mixture; S2, in the absence of oxygen, introducing hydrogen into the mixture to pressurize it, and performing a third stirring to obtain a polyethylene glycol-stabilized nano-rhodium catalyst; In the mixture, the mass ratio of the rhodium salt to the polyethylene glycol is 0.00001-0.00028:1, calculated on the basis of rhodium.

11. The method for hydrogenating nitrile rubber according to claim 10, wherein In the mixture, the mass ratio of the rhodium salt to the polyethylene glycol is 0.000025-0.00016:1, calculated as rhodium; Preferably, in step S2, the pressurization makes the system pressure be 3-6 MPa.

12. A hydrogenated nitrile rubber, characterized in that: Prepared by the method according to any one of claims 1 to 11; Wherein, when the polyethylene glycol-stabilized nano-rhodium catalyst is used once, the hydrogenation degree of the hydrogenated nitrile rubber is not less than 82%, and the residual rhodium content in the hydrogenated nitrile rubber is not more than 1 ppm; Alternatively, when the polyethylene glycol-stabilized nano-rhodium catalyst is used 5 times, the degree of hydrogenation of the hydrogenated nitrile rubber is not less than 82%, and the residual amount of rhodium in the hydrogenated nitrile rubber is not more than 5 ppm; Alternatively, when the polyethylene glycol-stabilized nano-rhodium catalyst is used 10 times, the degree of hydrogenation of the hydrogenated nitrile rubber is not less than 82%, and the residual amount of rhodium in the hydrogenated nitrile rubber is not more than 10 ppm.

13. Use of the hydrogenated nitrile rubber according to claim 12 in at least one of the fields of aerospace, oil field, transportation and deep sea.

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