A method for hydrogenating unsaturated bonds in a polymer

Abstract

The present invention discloses a method for hydrogenating unsaturated bonds in a polymer, comprising the following steps: Step (1): Pre-hydrogenation Mix the polymer to be treated with a homogeneous hydrogenation catalyst and introduce a hydrogen-containing gas to carry out a pre-hydrogenation reaction; Step (2): Hydrogenation Add a water source assistant to the pre-hydrogenation reaction in Step (1) to carry out a hydrogenation reaction to obtain a hydrogenated polymer; the water source assistant is at least one of a water-containing Lewis base and a compound with crystal water; in the water source assistant, the water content is less than or equal to 65 wt%; the molar ratio of the water in the water source assistant to the main catalytic active component of the homogeneous hydrogenation catalyst is 0.02 to 1.2:1. The present invention has found through research that, innovatively adding the water source assistant in the catalytic reaction stage and through the combined control of the form, water content and addition amount of the water source assistant, it will not only cause the reaction to quench, but also can unexpectedly promote the catalytic reaction and can effectively extend the hydrogenation activity of the catalyst.

Description

Technical Field

[0001] The present invention belongs to the field of polymer preparation, and particularly relates to the field of hydrogenation catalysis of polymers containing unsaturated bonds. Background Art

[0002] Hydrogenating polymers containing unsaturated bonds (such as olefin bonds, benzene rings, etc.) is one of the main means to obtain materials with different properties. There are mainly two types of hydrogenation reactions for polymers. One is the selective hydrogenation of non-aromatized unsaturated bonds (i.e., selective hydrogenation), and the conditions for selective hydrogenation are relatively mild. The other is the simultaneous deep hydrogenation of unsaturated bonds including non-aromatized and aromatic rings. Deep hydrogenation usually requires high temperature and high pressure treatment, and the degree of hydrogenation, especially the reaction efficiency in the later stage of hydrogenation, is not high. For example, the deep hydrogenation of styrene-conjugated diene copolymer is to hydrogenate the unsaturated bonds on the benzene ring while hydrogenating the olefinic unsaturated bonds to obtain a fully hydrogenated styrene-conjugated diene copolymer, which can be applied in fields with high requirements for high transparency, ultra-cleanliness and impact resistance, such as liquid crystal light guide films, biomedical detection (viral nucleic acid detection kits), medical pre-packaged infusion devices, food packaging and containers, etc. It has high added value and broad development prospects. However, achieving the full hydrogenation of styrene-conjugated diene copolymer has always been a technical problem. Commonly used hydrogenation methods include heterogeneous catalytic systems with noble metals supported on carriers such as silica and ziegler-type nickel / aluminum homogeneous catalytic systems. Among them, the homogeneous catalytic system is widely used in the hydrogenation of styrene-conjugated diene copolymer due to its simple process and high catalytic activity. At present, most of the research on homogeneous catalytic systems focuses on the preparation of catalysts. For example, US Patent US3625927 discloses a method for preparing a homogeneous catalyst, the main components of which are metal chelates of nickel, cobalt, and iron and alkyl metal compounds. This catalyst can better achieve the hydrogenation of conjugated dienes under mild conditions without hydrogenating the benzene ring, and has high selectivity. Chinese Patent CN102580774A introduces an unsaturated polymer hydrogenation catalyst and its preparation method, which is formed by reacting metal organic compounds of Group IA, IIA, and IIIA with nickel / cobalt metal inorganic salts. This catalyst has a significant hydrogenation effect on homopolymers of conjugated dienes or copolymers of conjugated dienes and vinyl aromatic hydrocarbons, has high hydrogenation selectivity, and is not easily retained in the polymer after hydrogenation and can be removed by washing with water. Chinese Patent CN104043482A discloses a homogeneous catalyst containing components such as metal organic carboxylates, alkyl aluminum / magnesium / lithium, and Lewis bases. This catalyst has a gentle reaction in the early stage of hydrogenation, high catalytic efficiency, and a long catalytic activity time, and has a good hydrogenation effect on conjugated diene copolymers.

[0003] However, in the existing nickel / aluminum homogeneous catalytic system, there are generally problems such as high catalytic activity in the early stage of hydrogenation, easy deactivation of the catalyst in the later stage, and large catalyst dosage. How to improve the activity of the catalyst in the later stage and shorten the hydrogenation reaction time is the key problem in the deep hydrogenation process of styrene-conjugated diene copolymer. Chinese Patent CN104945541A discloses that adding partial cocatalysts (alcohols, esters) before and during the hydrogenation reaction can prevent the deactivation of the nickel / aluminum composite catalyst, increase the hydrogenation catalytic activity in the later stage, and improve the hydrogenation efficiency. However, when using this method, the hydrogenation degree of vinyl aromatic hydrocarbons is less than 10%, which is only applicable to the selective hydrogenation of conjugated dienes and not applicable to the deep hydrogenation reaction of benzene ring hydrogenation. Summary of the Invention

[0004] In order to solve the problems of low catalyst activity in the later stage, large catalyst dosage, and long reaction time in the existing catalytic hydrogenation means, especially in the deep hydrogenation process, the present invention provides a brand-new method for hydrogenating unsaturated bonds in polymers, aiming to improve the reaction efficiency and hydrogenation effect of catalytic hydrogenation.

[0005] A method for hydrogenating unsaturated bonds in a polymer, comprising the following steps:

[0006] Step (1): Pre-hydrogenation

[0007] Mix the polymer to be treated with a homogeneous hydrogenation catalyst and introduce a hydrogen-containing gas to carry out a pre-hydrogenation reaction;

[0008] Step (2): Hydrogenation

[0009] Add a water source assistant to the pre-hydrogenation reaction in step (1) to carry out a hydrogenation reaction to obtain a hydrogenated polymer;

[0010] The water source assistant is at least one of a water-containing Lewis base and a compound with crystal water; in the water source assistant, the water content is less than or equal to 65 wt%;

[0011] The molar ratio of water in the water source assistant to the main catalytic active component of the homogeneous hydrogenation catalyst is 0.02 - 1.2:1.

[0012] The present invention discovers through research that innovatively adding the water source assistant in the catalytic reaction stage and controlling the addition method, form, water content, and addition amount of the water source assistant jointly can achieve synergy, not only will not cause the reaction to quench, but on the contrary, can unexpectedly promote the catalytic reaction, effectively extend the hydrogenation activity of the catalyst, improve the hydrogenation efficiency of unsaturated bonds, especially aromatic compounds, shorten the hydrogenation reaction time, thereby reducing the usage amount of the catalyst and reducing the removal pressure of catalyst metal ions after hydrogenation is completed.

[0013] The technical solution of the present invention can be used for the selective hydrogenation of non-aromatized unsaturated bonds and can also be used for the deep hydrogenation of unsaturated bonds containing aromatization. The technical solution of the present invention, especially in terms of deep hydrogenation, has greater advantages in improving hydrogenation efficiency and effect compared with the prior art.

[0014] The unsaturated bond is at least one of carbon-carbon -C=C- (monoalkenyl), -C=C-C=C- (conjugated diene group), and aromatic ring;

[0015] Preferably, the aromatic ring is a benzene ring, a five-membered heteroaromatic ring, a six-membered heteroaromatic ring, or a condensed ring or condensed heterocyclic ring formed by the fusion of two or more aromatic rings among a benzene ring, a five-membered heteroaromatic ring, and a six-membered heteroaromatic ring.

[0016] Preferably, the heteroatom in the five-membered heteroaryl group, six-membered heteroaryl group, and condensed heterocyclic ring is at least one of N, S, and O.

[0017] Preferably, the polymer is a living polymer containing random or block copolymerization of styrene and conjugated diene;

[0018] Preferably, the conjugated diene includes at least one of 1,3-butadiene, isoprene, piperylene, and methylpentadiene.

[0019] In the present invention, the polymer to be treated can be a polymerization system obtained by anionic polymerization to obtain a living polymer and then terminated.

[0020] In the present invention, the required living polymer can be obtained by using the well-known anionic polymerization method in the art. The living polymer can also be terminated by using the well-known means in the art.

[0021] For example, alkyl lithium and polymerization monomers are polymerized to obtain a living polymer (PLi), and then the termination reaction can be carried out with a conventional terminator.

[0022] Taking the polymer as an SBS block polymer as an example, the obtaining method is, for example:

[0023] In a polymerization kettle replaced with high-purity nitrogen, a polymerization solvent is added, a reaction assistant (such as a structure regulator tetrahydrofuran (50 - 1000 mg / kg), etc.) is added, alkyl lithium (for example, alkyl lithium of C1 - C6) and styrene monomer are added for the first-stage polymerization (the polymerization temperature is, for example, 60 - 65 °C), then conjugated diene is added for the second-stage polymerization (the polymerization temperature is, for example, 60 - 80 °C), and then styrene is added for the third-stage polymerization (the polymerization temperature is, for example, 60 - 65 °C) to obtain a living polymer (SBS-Li); then, through the termination reaction, the polymer to be treated is obtained.

[0024] In the present invention, the homogeneous hydrogenation catalyst is a composite catalyst comprising a catalytic active component and a catalytic promoter;

[0025] The catalytic active component is a metal organic compound; preferably an organic nickel; more preferably at least one of nickel naphthenate or nickel isooctanoate;

[0026] Preferably, the catalytic promoter is a metal alkyl or alkoxide of Group IIIA;

[0027] Preferably, Group IIIA is at least one of Al, Ga, and In;

[0028] Preferably, the metal alkyl or alkoxide of Group IIIA is a metal alkyl of C1-C6 alkyl of Group IIIA or a metal alkoxide of C1-C6 alkoxy; preferably at least one of triisobutylaluminum or aluminum methoxide.

[0029] Preferably, the homogeneous hydrogenation catalyst is a Ziegler-type nickel / aluminum catalyst.

[0030] Preferably, in the homogeneous hydrogenation catalyst, the molar ratio of nickel to the metal of Group IIIA is 1:2.5 - 4.0.

[0031] In the present invention, the dosage of the homogeneous catalyst can be adjusted based on existing means.

[0032] Preferably, the addition amount of the homogeneous hydrogenation catalyst relative to the polymer is 0.5 - 10 mmol / 100 g; more preferably 1 - 3 mmol / 100 g.

[0033] Preferably, the hydrogen-containing gas is hydrogen or a mixed gas of hydrogen and an inert gas; preferably hydrogen;

[0034] Preferably, the temperature of the pre-hydrogenation process is 70 - 80 °C;

[0035] Preferably, the time of pre-hydrogenation is 10 - 60 min;

[0036] The hydrogen partial pressure at this stage is 2.5 - 3.2 MPa.

[0037] In the technical solution of the present invention, innovatively adding a water source assistant component to the system after pre-hydrogenation, and cooperating with the control of its components and water content, can unexpectedly avoid reaction quenching and also unexpectedly improve the hydrogenation effect. That is, the synergistic control of the water source assistant component, addition method, water content, and water addition ratio is the key to solving reaction quenching and unexpectedly promoting the hydrogenation reaction.

[0038] In the technical solution of the present invention, the water source additive is preferably a hydrated Lewis base. When it is preferably a hydrated Lewis base, the preferred water content is 1-15 wt%; more preferably 5-10 wt%.

[0039] Preferably, the hydrated Lewis base is at least one of tetrahydrofuran, isopropanol, isooctanol, neopentyl alcohol, tert-butanol, cyclohexanol containing water. The present invention is not limited to this preferred selection, and similar variations also fall within the scope covered by the inventive concept of the present invention.

[0040] In another embodiment of the present invention, the water source additive may be a hydrated compound, and the water content is the crystal water carried by the hydrated compound itself.

[0041] Preferably, the hydrated compounds include but are not limited to at least one of sodium sulfate decahydrate, ferrous sulfate heptahydrate, potassium alum dodecahydrate, magnesium sulfate heptahydrate, zinc sulfate heptahydrate, copper sulfate pentahydrate. The present invention is not limited to this preferred selection, and similar variations also fall within the scope covered by the inventive concept of the present invention.

[0042] In the present invention, as a solution of the same inventive concept, the water source additive comprises a hydrated Lewis base and a hydrated compound; and preferably the water content of the hydrated Lewis base therein is 1-15 wt%; more preferably 5-10 wt%, and the water content of the compound with crystal water is its own crystal water.

[0043] Preferably, the molar ratio of the water of the water source additive to the main catalytic active ingredient (such as Ni therein) of the homogeneous hydrogenation catalyst is 0.1-1:1; more preferably 0.2-0.6:1.

[0044] More preferably, when the hydrated Lewis base is used as the water source additive, the molar ratio of the water in the water source additive to the main catalytic active ingredient (such as calculated by the molar amount of Ni in the nickel / aluminum catalyst) is 0.2-0.6, while when the hydrated compound is used as the water source additive, the molar ratio of the hydrated compound to the main catalytic active ingredient (such as calculated by the molar amount of Ni in the nickel / aluminum catalyst) is 0.03-0.1. When the water source additive contains both, the total molar ratio of the water to the main catalytic active ingredient of the catalyst is 0.2-0.6:1.

[0045] Preferably, the temperature of the hydrogenation reaction is 160-170 °C.

[0046] Preferably, the hydrogen partial pressure in the hydrogenation reaction stage is 2.5-3.2 MPa.

[0047] The time of the hydrogenation reaction can be controlled according to existing monitoring means. For example, the time of the hydrogenation reaction is 90-120 min.

[0048] A preferred method for deep hydrogenation of styrene-conjugated diene copolymer of the present invention includes anionic polymerization of styrene and conjugated diene to form an active base rubber. After termination, a Ziegler-type nickel / aluminum homogeneous hydrogenation catalyst is used for pre-reaction, and then a water source assistant is added, and hydrogenation is carried out at 160-170 °C and 2.5-3.2 MPa until a deeply hydrogenated styrene-conjugated diene copolymer is obtained. The present invention innovatively adds a water source assistant during the hydrogenation process, and further controls the addition timing, composition and addition amount of the water source in a coordinated manner, which not only does not cause quenching of the reaction by water, but also unexpectedly improves the catalytic performance, bringing better effects. The main introduction methods of the water source assistant described in the present invention include adding a hydrated Lewis base and a compound with crystal water. Among them, the hydrated Lewis base includes but is not limited to tetrahydrofuran, isopropanol, isooctanol, neopentyl alcohol, tert-butanol, cyclohexanol, etc., and the compound with crystal water includes but is not limited to sodium sulfate decahydrate, ferrous sulfate heptahydrate, potassium alum dodecahydrate, magnesium sulfate heptahydrate, zinc sulfate heptahydrate, copper sulfate pentahydrate, etc. The molar ratio of water in the water source assistant to the nickel / aluminum catalyst (homogeneous catalyst, calculated in terms of Ni molar) is 0.2-0.6:1.

[0049] In the preferred process of deep hydrogenation of styrene-conjugated diene of the present invention, the solubility parameter of the catalyst decreases, and it is difficult to dissolve in the non-polar system of cyclohexane. The active center of the catalyst is wrapped by the macromolecular chain and cannot move, resulting in a decrease in the binding ability between the benzene ring and the active center of the catalyst and a decrease in the hydrogenation efficiency. At this time, adding a small amount of water as a co-catalyst into the reaction system can significantly improve the catalytic hydrogenation activity and the hydrogenation efficiency. However, directly adding water to the hydrogenation reaction system easily reduces the activity of the nickel / aluminum catalyst, and even causes the catalyst to be poisoned and lose its activity. Therefore, a hydrated Lewis base or a compound with crystal water is used to introduce water into the reaction system (where the compound with crystal water decomposes to generate water molecules under the high temperature during the hydrogenation process). Under the high temperature and high pressure hydrogenation conditions, the two lone pairs of electrons of the water molecule become active, which can release the active center of the catalyst from the wrapping of the macromolecular chain, improve the binding degree between the active center of the catalyst and the benzene ring, and contribute to improving the later hydrogenation activity and the benzene ring hydrogenation degree.

[0050] The beneficial effects of the present invention:

[0051] The present invention innovatively adds the above-mentioned water source assistant to the pre-hydrogenation system, and further realizes coordination based on the combined control of the composition, water content and addition amount of the water source assistant. It not only does not quench the reaction, but on the contrary, can unexpectedly improve the catalytic performance, especially improve the catalyst activity in the later stage of the deep hydrogenation reaction, improve the hydrogenation efficiency and the aromatic ring hydrogenation degree, reduce the amount of catalyst used, and shorten the reaction time. High-efficiency and deep hydrogenation are achieved. Specific embodiments

[0052] The following is a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not intended to limit the present invention.

[0053] In the examples and comparative examples, the degree of hydrogenation was obtained by calculation based on nuclear magnetic resonance hydrogen spectrum, measured at room temperature using a Bruker AV400 spectrometer (400 MHz), with CDCl3 as the solvent.

[0054] Degree of hydrogenation % = [(moles of double bonds in styrene-conjugated diene copolymer - moles of double bonds in the product after hydrogenation reaction) / moles of double bonds in styrene-conjugated diene copolymer] × 100%. It represents the degree of double bond saturation in the hydrogenated product, where the degree of hydrogenation of the benzene ring and diene is calculated separately based on the double bonds of the benzene ring and diene.

[0055] The hydrogenation catalyst described in the present invention can be a well-known homogeneous catalyst. For example, in the following cases, unless otherwise specified, the nickel-aluminum catalyst is a cyclohexane solution of nickel isooctanoate / triethylaluminum, where the molar ratio of nickel to aluminum is 1:3.

[0056] The molar amount of the catalyst is calculated based on the molar amount of Ni therein;

[0057] The molar amount of the water source additive (also known as cocatalyst) is calculated based on the molar amount of water therein.

[0058] Example 1

[0059] Step (1-a): Synthesis of polymerization rubber

[0060] Add 2500 mL of pure cyclohexane into a 5 L polymerization kettle, start stirring, heat up to 60 °C, add tetrahydrofuran in an amount equivalent to 300 mg / kg of the solvent, add 4.0 mmol of n-butyllithium in one stage and polymerize with 60 g of styrene monomer for 30 minutes, then add 180 g of butadiene monomer in the second stage, control the reaction temperature below 80 °C (70 - 75 °C) by means of jacket water cooling, after reacting for 40 minutes, add 60 g of styrene monomer in the third stage, and react at a temperature of 60 - 65 °C for 30 minutes. Add a terminator (trimethylchlorosilane, 1.2 times the molar amount of active lithium) to terminate the active chain for use in hydrogenation.

[0061] Step (1-b): Hydrogenation of polymerization rubber

[0062] Introduce the polymerized glue solution into a 5L hydrogenation autoclave, stir and heat up to 70 - 80 °C, introduce hydrogen (hydrogen partial pressure is 2.5 - 3.2 MPa), add 2 mmol / 100 g of aluminum-nickel catalyst for catalytic hydrogenation (pre-hydrogenation). After reacting for half an hour, add a tetrahydrofuran solution containing water (water content is 10 wt%) as a co-catalyst (water source assistant), and the molar ratio of its dosage to the catalyst is 0.4. React under the conditions of 160 - 170 °C and 2.5 - 3.2 MPa (hydrogen partial pressure) for 2 hours. Sample and analyze the hydrogenation degree of the polymer every 1 hour. The specific data is shown in Table 1.

[0063] Example 2

[0064] Synthesize the hydrogenated polymer according to the method of Example 1. The difference is that the co-catalyst used is a neopentyl alcohol solution containing water (water content is 10 wt%). The specific data is shown in Table 1.

[0065] Example 3

[0066] Synthesize the hydrogenated polymer according to the method of Example 1. The difference is that the co-catalyst used is an isopropyl alcohol solution containing water (water content is 10 wt%). The specific data is shown in Table 1.

[0067] Example 4

[0068] Synthesize the hydrogenated polymer according to the method of Example 1. The difference is that the molar ratio of the co-catalyst to the aluminum-nickel catalyst is 0.2. The specific data is shown in Table 1.

[0069] Example 5

[0070] Synthesize the hydrogenated polymer according to the method of Example 1. The difference is that the molar ratio of the co-catalyst to the aluminum-nickel catalyst is 0.6. The specific data is shown in Table 1.

[0071] Example 6

[0072] Synthesize the hydrogenated polymer according to the method of Example 1. The difference is that the co-catalyst used is sodium sulfate decahydrate, and the molar ratio of its dosage to the aluminum-nickel catalyst is 0.6 (the molar ratio of sodium sulfate decahydrate to nickel in the catalyst is 0.06). The specific data is shown in Table 1.

[0073] Example 7

[0074] Synthesize the hydrogenated polymer according to the method of Example 1. The difference is that the co-catalyst used is potassium alum dodecahydrate, and the molar ratio of its dosage to the aluminum-nickel catalyst is 0.6 (the molar ratio of potassium alum dodecahydrate to nickel in the catalyst is 0.05). The specific data is shown in Table 1.

[0075] Example 8

[0076] Compared with Example 1, the only difference is that the water content of the tetrahydrofuran containing water is 15 wt%, and other parameters are the same as those in Example 1.

[0077] Example 9

[0078] Compared with Example 1, the only difference is that the water content of the aqueous tetrahydrofuran is 5wt%, and the other parameters are the same as Example 1.

[0079] Example 10

[0080] Compared with Example 1, the only difference is that the water content of the aqueous tetrahydrofuran is 1wt%, and the other parameters are the same as Example 1.

[0081] Embodiment 11

[0082] Compared with Example 1, the only difference is that the molar ratio of the aqueous additive to the catalyst is 1.2:1, and the other parameters are the same as Example 1.

[0083] Example 12

[0084] Compared with Example 1, the only difference is that the molar ratio of the aqueous additive to the catalyst is 0.1:1, and the other parameters are the same as Example 1.

[0085] Comparative Example 1

[0086] The hydrogenated polymer was synthesized according to the method of Example 1, except that water was used as the co-catalyst. Other parameters and conditions were the same as those of Example 1. Specific data are shown in Table 1.

[0087] Comparative Example 2

[0088] The hydrogenated polymer was synthesized according to the method of Example 1, except that anhydrous isopropanol was used as the co-catalyst (the amount of anhydrous isopropanol added was the same as that of Example 3), and other parameter conditions were the same as those of Example 3. Specific data are shown in Table 1.

[0089] Comparative Example 3

[0090] The hydrogenated polymer was synthesized according to the method of Example 1, except that anhydrous neopentyl alcohol was used as the co-catalyst (the addition amount was the same as that of Example 2), and other parameter conditions were the same as those of Example 2. Specific data are shown in Table 1.

[0091] Comparative Example 4

[0092] The hydrogenated polymer was synthesized according to the method of Example 1, except that anhydrous tetrahydrofuran was used as the co-catalyst (the amount of anhydrous isopropanol added was the same as in Example 1), and other parameters and conditions were the same as in Example 1. Specific data are shown in Table 1.

[0093] Comparative Example 5

[0094] The hydrogenated polymer was synthesized according to the method of Example 1, except that anhydrous sodium sulfate was used as the co-catalyst, and the molar ratio of the amount to the catalyst was 0.06. The specific data are shown in Table 1.

[0095] Comparative Example 6

[0096] The hydrogenated polymer was synthesized according to the method of Example 6, except that the cocatalyst used was anhydrous potassium alum, and the molar ratio of the amount used to the catalyst was 0.05. The specific data are shown in Table 1.

[0097] Comparative Example 7

[0098] The hydrogenated polymer was synthesized according to the method of Example 1, except that no cocatalyst was added. The specific data are shown in Table 1.

[0099] Comparative Example 8

[0100] Compared with Example 1, the difference is only that the aqueous tetrahydrofuran solution was added to the reaction system before the pre-hydrogenation reaction. The steps are as follows:

[0101] Step (1-b): Hydrogenation of the polymer gum

[0102] The polymer gum solution was introduced into a 5 L hydrogenation autoclave, stirred and heated to 70 - 80 °C, hydrogen was introduced, 2 mmol / 100 g of an aluminum-nickel catalyst and a tetrahydrofuran solution with a water content of 10 wt% were added as a cocatalyst (water source assistant, the amount used was the same as in Example 1), and catalytic hydrogenation (pre-hydrogenation) was carried out. After reacting for half an hour, the reaction was carried out for another 2 hours under the conditions of 160 - 170 °C and 2.5 - 3.2 MPa. The hydrogenation degree of the polymer was analyzed by sampling every 1 hour. The specific data are shown in Table 1.

[0103] Comparative Example 9

[0104] Compared with Example 6, the difference is only that sodium sulfate decahydrate was added to the reaction system before the pre-hydrogenation reaction. The steps are as follows:

[0105] Step (1-b): Hydrogenation of the polymer gum

[0106] The polymer gum solution was introduced into a 5 L hydrogenation autoclave, stirred and heated to 70 - 80 °C, hydrogen was introduced, 2 mmol / 100 g of an aluminum-nickel catalyst and sodium sulfate decahydrate were added as a cocatalyst (water source assistant, the amount used was the same as in Example 6), and catalytic hydrogenation (pre-hydrogenation) was carried out. After reacting for half an hour, the reaction was carried out for another 2 hours under the conditions of 160 - 170 °C and 2.5 - 3.2 MPa. The hydrogenation degree of the polymer was analyzed by sampling every 1 hour. The specific data are shown in Table 1.

[0107] Comparative Example 10

[0108] Compared with Example 1, the difference is only that pre-hydrogenation was not carried out. The steps are as follows:

[0109] Step (1-b): Hydrogenation of the polymer gum

[0110] Introduce the polymerized glue solution into a 5L hydrogenation autoclave, introduce hydrogen, add 2 mmol / 100 g of aluminum-nickel catalyst, and a tetrahydrofuran solution containing water (water content is 10 wt%) as a co-catalyst (water source assistant), and the dosage is in a molar ratio of 0.4 to the catalyst. React for 2 hours under the conditions of 160 - 170 °C and 2.5 - 3.2 MPa. Sample and analyze the hydrogenation degree of the polymer every 1 hour. The specific data is shown in Table 1.

[0111] Table 1 Data table of different co-catalysts and addition amounts and the hydrogenation degree of the polymer

[0112]

[0113]

[0114] As can be seen from Table 1, using the above-mentioned water-containing Lewis base or hydrated compound as a co-catalyst can improve the reaction activity of the catalyst. From the data of the 1-hour reaction, it can be seen that compared with the case without adding a co-catalyst, the catalytic activity and hydrogenation efficiency are significantly improved. The hydrogenation degree of the polymer benzene ring generally increases by more than 20%. The hydrogenation degree of the polymer benzene ring after 2 hours is greater than 98%, and the hydrogenation degree of the diene is greater than 99%. During the hydrogenation process of styrene-conjugated diene copolymer, when directly adding water as a co-catalyst, it is difficult to improve the activity of the nickel / aluminum catalyst, and the hydrogenation degree of the obtained polymer is relatively low; when using other water-free co-catalysts, the improvement of the catalyst activity is not obvious and the hydrogenation efficiency is not high; when adding a water source assistant before the pre-hydrogenation reaction or directly adding the catalyst and the water source assistant together in the polymerized base rubber without pre-hydrogenation reaction for hydrogenation, the activity is significantly improved in the early stage of the reaction, but the hydrogenation efficiency is not high in the later stage of the reaction, and it cannot meet the requirement of deep hydrogenation of the benzene ring (hydrogenation degree of benzene ring ≥ 98%).

Claims

1. A method for hydrogenating unsaturated bonds in a polymer, characterized in that, It includes the following steps: Step (1): Pre-hydrogenation Mix the polymer to be processed with a homogeneous hydrogenation catalyst, and introduce a hydrogen-containing gas to carry out pre-hydrogenation reaction; Step (2): Hydrogenation Add a water source assistant to the pre-hydrogenation reaction in step (1) to carry out hydrogenation reaction to obtain a hydrogenated polymer; The water source assistant is at least one of a water-containing Lewis base and a compound with crystal water; in the water source assistant, the water content is less than or equal to 65 wt%; The molar ratio of water in the water source assistant to the main catalytic active ingredient of the homogeneous hydrogenation catalyst is 0.02~1.2:1; The unsaturated bond is at least one of -C=C-, -C=C-C=C-, and aromatic ring; The water-containing Lewis base is at least one of tetrahydrofuran, isopropanol, isooctanol, neopentyl alcohol, tert-butanol, and cyclohexanol containing water.

2. The method for hydrogenating unsaturated bonds in the polymer according to claim 1, characterized in that, The aromatic ring is a benzene ring, a five-membered heteroaromatic ring, a six-membered heteroaromatic ring, or a condensed ring or condensed hetero ring formed by the fusion of two or more aromatic rings among a benzene ring, a five-membered heteroaromatic ring, and a six-membered heteroaromatic ring.

3. The method for hydrogenating unsaturated bonds in the polymer according to claim 2, characterized in that, The heteroatom in the five-membered heteroaromatic ring, six-membered heteroaromatic ring, and condensed hetero ring is at least one of N, S, and O.

4. The method for hydrogenating unsaturated bonds in the polymer according to claim 1, characterized in that, The polymer is an active polymer containing styrene and conjugated diene in random or block copolymerization.

5. The method for hydrogenating unsaturated bonds in the polymer according to claim 4, characterized in that, The conjugated diene includes at least one of 1,3-butadiene, isoprene, piperylene, and methylpentadiene.

6. The method for hydrogenating unsaturated bonds in the polymer according to claim 1, characterized in that, The homogeneous hydrogenation catalyst is a composite catalyst containing a catalytic active ingredient and a catalytic assistant; The catalytic active ingredient is a metal organic compound.

7. The method for hydrogenating unsaturated bonds in the polymer according to claim 6, characterized in that, The catalytic active ingredient is an organic nickel.

8. The method for hydrogenating unsaturated bonds in the polymer according to claim 7, characterized in that, The catalytic active ingredient is at least one of nickel naphthenate or nickel isooctanoate.

9. The method for hydrogenating unsaturated bonds in the polymer according to claim 6, characterized in that, The catalytic assistant is a metal alkyl compound or alkoxide of Group IIIA.

10. The method for hydrogenating unsaturated bonds in the polymer according to claim 9, characterized in that, Group IIIA is at least one of Al, Ga, and In.

11. The method for hydrogenating unsaturated bonds in the polymer according to claim 9, characterized in that, The metal alkyl compound or alkoxide of Group IIIA is a metal alkyl compound of C1~C6 alkyl of Group IIIA or a metal alkoxide of C1~C6 alkoxy.

12. The method for hydrogenating unsaturated bonds in the polymer according to claim 11, characterized in that, The metal alkyl compound or alkoxide of Group IIIA is at least one of triisobutylaluminum or aluminum methoxide.

13. The method for hydrogenating unsaturated bonds in the polymer according to claim 1, characterized in that, The homogeneous hydrogenation catalyst is a Ziegler-type nickel / aluminum catalyst.

14. The method for hydrogenating unsaturated bonds in the polymer according to claim 1, characterized in that, The addition amount of the homogeneous hydrogenation catalyst relative to the polymer is 0.5~10 mmol / 100 g.

15. The method for hydrogenating unsaturated bonds in the polymer according to claim 1, characterized in that, The addition amount of the homogeneous hydrogenation catalyst relative to the polymer is 1~3 mmol / 100 g.

16. The method for hydrogenating unsaturated bonds in the polymer according to claim 1, characterized in that, The hydrogen-containing gas is hydrogen or a mixed gas of hydrogen and an inert gas.

17. The method for hydrogenating unsaturated bonds in the polymer according to claim 1, characterized in that, The temperature of the pre-hydrogenation process is 70~80 °C.

18. The method for hydrogenating unsaturated bonds in the polymer according to claim 1, characterized in that, The time of pre-hydrogenation is 10~60 min.

19. The method for hydrogenating unsaturated bonds in the polymer according to claim 1, characterized in that, The hydrogen partial pressure in the pre-hydrogenation stage is 2.5~3.2 MPa.

20. The method for hydrogenating unsaturated bonds in the polymer according to any one of claims 1 to 19, characterized in that, The water source assistant is a water-containing Lewis base, and its water content is 1~15 wt%.

21. The method for hydrogenating unsaturated bonds in the polymer according to claim 20, characterized in that, The water source assistant is a water-containing Lewis base, and its water content is 5~10 wt%.

22. The method for hydrogenating unsaturated bonds in the polymer according to any one of claims 1 to 19, characterized in that, The water source assistant is a compound with crystal water, and the water content is the content of the crystal water it contains.

23. The method for hydrogenating unsaturated bonds in the polymer according to claim 22, characterized in that, The compound with crystal water includes at least one of sodium sulfate decahydrate, ferrous sulfate heptahydrate, potassium alum dodecahydrate, magnesium sulfate heptahydrate, zinc sulfate heptahydrate, and copper sulfate pentahydrate.

24. The method for hydrogenating unsaturated bonds in the polymer according to claim 1, characterized in that, The described water source assistant contains a hydrated Lewis base and a hydrated compound.

25. The method for hydrogenating unsaturated bonds in the polymer according to claim 1, characterized in that, The molar ratio of the water in the water source assistant to the main catalytic active ingredient of the homogeneous hydrogenation catalyst is 0.1 - 1:

1.

26. The method for hydrogenating unsaturated bonds in the polymer according to claim 25, characterized in that, The molar ratio of the water in the water source assistant to the main catalytic active ingredient of the homogeneous hydrogenation catalyst is 0.2 - 0.6:

1.

27. The method for hydrogenating unsaturated bonds in the polymer according to claim 1, characterized in that, The temperature of the hydrogenation reaction is 160 - 170 °C.

28. The method for hydrogenating unsaturated bonds in the polymer according to claim 1, characterized in that, The hydrogen partial pressure in the hydrogenation reaction stage is 2.5 - 3.2 MPa.

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