KR19990015840A - Preparation of New Catalyst for Selective Hydrogenation of Double Bond of Olefin Living Polymer and Hydrogenation Method Using The Same - Google Patents

Abstract

The present invention relates to the preparation of a homogeneous organic titanium catalyst having a high activity for selectively hydrogenating a living polymer having an olefinic double bond and a hydrogenation reaction using the catalyst. More specifically, to prepare an organic titanium-based hydrogenated catalyst having a plurality of catalytically active sites prepared by reacting a macromolecule having several alkoxy groups having a steric hindrance in one molecule with a monocyclopentadienyl titanium trihalogen compound, By hydrogenation using this catalyst, the present invention relates to a method of selectively hydrogenating a living polymer having an olefinic double bond in high yield, high selectivity and high reproducibility.

Description

Preparation of New Catalyst for Selective Hydrogenation of Double Bond of Olefin Living Polymer and Hydrogenation Method Using The Same

The present invention relates to the preparation of a homogeneous organic titanium catalyst having a high activity for selectively hydrogenating a living polymer having an olefinic double bond and a hydrogenation reaction using the catalyst. More specifically, an organic titanium-based hydrogenation catalyst having several catalytically active sites prepared by reacting a macromolecule having several alkoxy groups having a steric hindrance in a molecule with a monocyclopentadienyl titanium trihalogen compound and the catalyst The present invention relates to a method of selectively hydrogenating a living polymer having an olefinic double bond in high yield, high selectivity and high reproducibility by performing a hydrogenation reaction.

Copolymers of conjugated diene monomers such as 1,3-butadiene and isoprene with vinylaromatic monomers such as styrene and alphamethyl styrene that are copolymerizable with conjugated diene monomers are widely used as elastomers. Block copolymers of these conjugated diene monomers and vinylaromatic monomers, which are thermoplastic elastomers, are used as modifiers for polyolefins and polystyrene resins to make transparent resins having impact resistance. However, these copolymers are mainly used in the range that their use is limited and not exposed to the outside due to the disadvantage of the durability and oxidation resistance to oxygen and ozone in the air due to the presence of olefinic double bonds in the polymer. In general, in order to improve the durability and oxidation resistance of such a copolymer, it is only necessary to partially or completely saturate by adding hydrogen to the olefinic double bonds in the polymer.

Many methods have been reported for the hydrogenation of polymers having an olefinic double bond, which can be broadly divided into organic salts such as nickel, cobalt, iron, chromium, titanium, and organoaluminum, or similar ring reducing agents. A method using a Ziegler-based catalyst or a homogeneous catalyst such as an organometallic compound such as rhodium or titanium, and metals such as nickel, palladium, platinum, rudenium and the like are dispersed in a carrier such as carbon, silica, aluminum or calcium carbonate. There is a method using a heterogeneous catalyst.

Hydrogenation using heterogeneous catalysts involves dissolving the olefinic polymer in an appropriate solvent and then contacting it with hydrogen in the presence of heterogeneous catalysts, making contact between the reactants and the catalyst difficult due to the steric hindrance of the polymer and the relatively high viscosity. . Also, due to the strong adsorption between the catalyst and the polymer, it is very difficult for the non-hydrogenated polymer to reach the active point of the catalyst. In this case, in order to completely hydrogenate the double bonds, a large amount of catalyst and high-temperature and high-pressure reaction conditions are often required, which often causes decomposition and gelation of the polymer, and copolymers of conjugated diene and vinylaromatic monomers. In the case of, the saturation of the aromatic double bond proceeds simultaneously, so that the selective hydrogenation of the olefinic polymer is very difficult. In addition, it is extremely difficult to physically separate the catalyst from the hydrogenated polymer solution, and some heterogeneous catalysts cannot be completely removed by strong adsorption with the polymer.

On the other hand, the hydrogenation reaction using a homogeneous catalyst is generally higher in activity than the heterogeneous catalyst, and high yield can be expected at low and low pressure reaction conditions in a small amount. Furthermore, under suitable hydrogenation conditions, there is an advantage in that only a double bond excluding the aromatic hydrocarbon portion can be selectively hydrogenated in the copolymer chain of vinylaromatic hydrocarbon and conjugated diene.

For example, hydrogenation of conjugated diene polymers or methods with selective hydrogen, US Pat. Nos. 3,494,942, 3,634,594, 3,670,054, and 3,700,633 and the like are described in the prior art for hydrogenating or selectively hydrogenating polymers having ethylenically unsaturated groups. It has been reported to use known suitable catalysts, in particular catalysts or catalyst precursors containing the Group VIII metals of the Periodic Table of Elements. In the process described in this patent, the catalyst is prepared by combining a Group VIII metal of the Periodic Table of Elements, in particular a nickel or cobalt compound, with a reducing agent such as an aluminum alkyl compound. It is also described in the prior art that aluminum alkyl is the preferred reducing agent, but the I-A, II-A and III-B metals of the periodic table of the elements, in particular lithium, magnesium and aluminum alkyl or hydrides, are effective reducing agents. In general, the molar ratios of metals I-A, II-A and III-B to Group VIII metals of the Periodic Table of the Elements are combined in the range of 0.1: 1 to 20: 1, preferably 1: 1 to 10: 1. US Pat. No. 4,501, 857 discloses selective hydrogenation of double bonds in the polymer by hydrogenating a conjugated diene polymer in the presence of at least one bis (cyclopentadienyl) titanium compound and at least one hydrocarbonlithium compound. However, as the molar ratio of Li / Ti is changed, it is difficult to obtain extremely high hydrogenation rate and high reproducibility, and this requires preconditions to control the exact molar ratio.

As a result, it is not easy to simultaneously satisfy the high hydrogenation rate and the high reproducibility according to the change in the molecular weight of the polymer and the number of moles of the living polymer. In addition, the anion of the living polymer may cause crosslinking between the polymers before and after the hydrogenation process to form a high molecular weight material, and may also act as a factor for reducing the catalytic activity by changing the reduction state of the catalyst. U.S. Patent No. 4,980,421 is similar to the above patents and discloses alkoxy lithium compounds, bis (cyclopentadienyl) titanium compounds and organometallic reducing agents which may be added directly or as reaction mixtures with organolithium compounds and alcoholic or phenolic compounds. It was found that the combination can have a pseudohydrogenation activity. It has also been mentioned that the catalyst is active and does not require a deliming step so that the catalyst can be effective even in small amounts, which does not adversely affect the stability of the hydrogenated polymer, but this technique uses polymers in continuous processing due to the use of alcoholols and phenols. May affect molecular weight control, and alcohols and phenols that do not turn into alkoxylithium may act as poisons of catalytically active species. US Patent No. 4,673,714 shows that in selectively hydrogenating polymers having olefinic double bonds, bis (cyclopentadienyl) titanium compounds preferably hydrogenate the double bonds of conjugated dienes but do not require the use of alkyllithium. Such a compound is a bis (cyclopentadienyl) titanium diaryl compound and mentions the absence of a hydrocarbon lithium compound as an advantage of this catalyst system.

U.S. Patent No. 5,039,755 discloses a living polymer by polymerizing or copolymerizing a conjugated diene monomer with an organoalkali metal polymerization initiator in a suitable solvent, and then terminating the polymerization by addition of hydrogen, and the double bond of the conjugated diene unit of the terminated polymer. Hydrogenation has been reported using (C ₅ H ₅ ) ₂ TiR ₂ (R = arylalkyl group) as catalyst. However, the reaction of inactivating the living polymer using hydrogen requires an effective mixing of the liquid phase and the gaseous phase, which leads to severe temperature and pressure conditions and a long reaction time. Moreover, since the reaction activity varies depending on the molar ratio between Li and Ti, it is difficult to satisfy the high activity and high reproducibility of the catalyst at the same time. In this respect, a new type of catalyst system with high reaction activity and reproducibility is urgently needed. In general, the hydrogenation reaction using a homogeneous catalyst greatly changes the hydrogenation activity according to the reduction state of the catalyst, and therefore, the reproducibility of the hydrogenation reaction is inferior. Therefore, it is difficult to obtain a hydrogenated polymer by satisfying high yield and high reproducibility at the same time. have. In addition, since the catalytically active component tends to change into an inactive substance due to impurities in the reaction system, the impurities in the reactor act as a cause of lowering the hydrogenation activity of the catalyst and reducing the reproducibility of the reaction.

The hydrogenation reaction using the conventional homogeneous catalyst causes the formation and decomposition of polymers between catalytically active species due to the relatively high temperature and high pressure conditions involved in the hydrogenation reaction. Eventually, the activity of the catalytic species is inactivated through this process and thus it is not possible to induce the hydrogenation reaction as desired. This tendency causes serious obstacles to the hydrogenation of polymers for the purpose of improving the durability and oxidation resistance of the polymers by hydrogenation of the polymers, which is problematic for industrial applications. Therefore, there is a strong demand for the development of a highly active hydrogenation catalyst that satisfies high hydrogenation reproducibility at the same time.

In addition, more economical hydrogenation processes require more active and stable catalysts with more efficient and lower catalyst amounts than the homogeneous catalysts mentioned above. In addition, there is a need for a catalyst system that avoids the cumbersome process of removing catalyst residues from the hydrogenated polymer after the reaction.

Accordingly, the present invention provides a method for selectively hydrogenating unsaturated double bonds in conjugated diene units in a cyclopentadienyl titanium-based hydrogenated catalyst represented by the following general formula (I) and a living polymer having an olefinic double bond using the catalyst. It is about a method.

R is an organotitanium compound having the structure

In the above formula;

X ₁ and X ₂ are the same or different from each other and are a substituent selected from the group consisting of a halogen group, a C ₁ to C ₈ alkyl group, a cycloalkyl group, an alkoxy group, a C ₆ or more aryloxy group, a silyl group and a carbonyl group.

Particularly preferred catalysts are those in which the substituents X ₁ and X ₂ in the catalyst compound of formula (I) are both chlorine.

In addition, the living polymer used for the hydrogenation reaction is characterized in that the living polymer in which at least one conjugated diene is polymerized or copolymerized in the presence of an organic alkali metal polymerization initiator in an inert organic solvent. At this time, the preferred organic alkali metal polymerization initiator is characterized in that the organolithium compound. In addition, the reaction conditions of the hydrogenation reaction is carried out under a reaction temperature of 0 ~ 150 ℃, preferably a reaction temperature of 50 ~ 150 ℃ under a pressure of 1 ~ 100kg / ㎠, preferably 2 ~ 30 kg / ㎠, In this case, the amount of the organotitanium compound used as the catalyst is in the range of 0.01 to 20 mmol, preferably 0.05 to 5 mmol, per 100 g of the living polymer. The hydrogen contact time is several seconds to 500 hours, and preferably about 30 to 360 minutes. On the other hand, the molar ratio of living lithium in the living polymer and titanium in the catalyst is in the range of 2: 1 to 10: 1.

Hereinafter, the present invention will be described in more detail.

In other words, the catalyst synthesized in the present invention is to avoid the problems of the general homogeneous hydrogenation catalyst, and by combining three catalyst species with macromolecules, In order to prevent inactivation, three catalyst species per macromolecule are combined, and by utilizing the instantaneous reactivity of the catalyst species, more catalyst species are developed at once than the time required for the inactivation of the catalyst species. By allowing the reaction to take place, a monocyclopentadienyl titanium compound catalyst with very high hydrogenation activity capable of producing a hydrogenated polymer with high hydrogenation rate and high reproducibility has been prepared.

By using the hydrogenated catalyst prepared according to the present invention, a conjugated diene unit of a living copolymer of a vinyl substituted aromatic monomer copolymerizable with a conjugated diene living polymer or a conjugated diene monomer having a molecular weight of 500 to 1,000,000 and a random or block copolymer Selective hydrogenation of unsaturated double bonds is possible.

The polymers containing ethylenic and aromatic unsaturations used in the hydrogenation reaction are then prepared by copolymerizing one or more polyolefins, in particular diolefins, alone or with one or more alkenyl aromatic hydrocarbon monomers. The copolymer can be linear or radial and can be random, tapered, block or a combination thereof.

Copolymers containing both ethylenic unsaturations or aromatics and ethylenic unsaturations can be prepared by using anionic initiators or polymerization catalysts, such as organolithium compounds, which may be bulk, solution or emulsion technology. Conjugated dienes capable of anionic polymerization methods are 1,3-butadiene, isoprene, piperylene, phenylbutadiene, 3,4-dimethyl-1,3-hexadiene, 4,5-diethyl-1,3-octadiene, and the like. A conjugated diene compound containing C ₄ to C ₁₂ is possible, and preferably a conjugated diolefin compound containing C ₄ to C ₉ is possible. Copolymerizable alkenyl aromatic hydrocarbons include vinyl aryl compounds such as styrene, various alkyl-substituted styrenes, alkoxy-substituted styrenes, 2-vinylpyridine, 4-vinylpyridine, vinylnaphthalene, alkyl-substituted naphthalenes and the like.

Hereinafter, the hydrogenation reaction using the catalyst of the present invention will be described in more detail.

The hydrogenation reaction using the hydrogenation catalyst prepared according to the present invention is carried out by maintaining the constant temperature of the living polymer solution in a hydrogen atmosphere, adding a hydrogenation catalyst in a stirred or unstirred state, and then injecting hydrogen gas at a constant pressure. . Air or oxygen is not preferable because it causes oxidization or decomposition of the hydrogenation catalyst to lower the activity of the catalyst. In the hydrogenation reaction of the living polymer according to the present invention, the ratio of the amount of reducing lithium and the amount of titanium in the living polymer is preferably in the range of 2: 1 to 10: 1. Therefore, in order to maintain the ratio of lithium to titanium at 2 to 10, it is preferable to maintain the amount of hydrogenation catalyst per 0.05 g of living polymer at 0.05 to 5 mmoles.

The hydrogenation reaction is generally carried out in the temperature range of 0 to 150 ℃. If the temperature is lower than 0 DEG C, the activity of the catalyst is lowered and the hydrogenation rate is also lowered. Therefore, a large amount of catalyst is required, so that the hydrogenated polymer is not economical and easily precipitates by insolubilization. At temperatures exceeding 150 ° C, catalyst deactivation and gelation / decomposition of polymers are likely to occur, and aromatic double bonds tend to hydrogenate, and hydrogenation selectivity tends to be lowered. Therefore, the preferable reaction temperature is a suitable temperature range of 50 ~ 150 ℃.

In addition, the pressure of hydrogen used for the hydrogenation reaction is not particularly limited, 1 ~ 100 kg / ㎠ is suitable. The hydrogenation rate becomes slower than 1 kg / cm <2>, and it is not good at the pressure exceeding 100 kg / cm <2> because side reaction gelation is caused. Therefore, the preferred hydrogen pressure is 2 to 30 kg / cm 2, and the optimum hydrogen pressure is selected in relation to the hydrogenation conditions such as the addition amount of the catalyst, and when the amount of the hydrogenation catalyst is small, it is preferable to select the hydrogen pressure as the high pressure.

The hydrogenation reaction time of the present invention is usually several seconds to 500 hours. The hydrogenation reaction time according to the change of hydrogenation reaction conditions can be suitably selected within the said range. The hydrogenation reaction of the present invention may be any method such as batch or continuous, and it can be understood that the progress of the hydrogenation reaction tracks the hydrogen absorption amount. In the present invention, the unsaturated double bond of the conjugated diene unit of the polymer can be obtained at least 50%, preferably at least 90%, of the hydrogenated hydrogenated polymer.

The hydrogenated polymer after the hydrogenation reaction can be easily separated by a conventional separation process. For example, a method of precipitating and recovering a polymer by adding a polar solvent such as acetone or alcohol to the reaction solution after the hydrogenation reaction, a method of separating the solvent and the polymer by adding the reaction solution into a boiling water under stirring, or heating the solvent directly by heating the reaction solution It is possible to distill off the method.

As described above, the conjugated diene polymer is hydrogenated under mildly active conditions under a highly active catalyst, and particularly the hydrogenated unsaturated double bond of the conjugated diene unit of the copolymer of conjugated diene and a vinyl-substituted aromatic hydrocarbon is extremely selectively hydrogenated. It is possible. In particular, in the method of the present invention, the living polymer is used as a raw material, and it is economical, such as being able to continuously hydrogenate the same reactor, at the same time exhibiting extremely high activity by adding a small amount of catalyst, and not requiring a deliming process after the hydrogenation. It is an easy process and has industrially advantageous properties.

The present invention is specifically limited to the following synthesis examples and examples. However, the present invention is not limited to these synthesis examples and examples.

Synthesis Example 1

Preparation of the catalyst

One mmol of Irganox 1330, one of the antioxidants for the olefin polymer, was reacted with 3 mmol of n-butyllithium in 10 ml of toluene solvent, followed by 3 mmol of cyclopentadienyl titanium trichloride for 1 hour at room temperature. . The obtained catalyst species

Analysis by ¹ H-NMR yield was calculated to 97%.

¹ H-NMR: 6.955 ppm (6H, Ar-H); 6.647 ppm (15H, Cp); 4.105 (6H, Ar-CH ₂ ); 2.272 ppm (9H, Ar-CH ₃ ); 1.343 ppm (54H, t-Bu)

Synthesis Example 2

Preparation of Living Copolymer

Into a 2 gallon autoclave reactor, 4,500 g of cyclohexane was added, 9 g of tetrahydrofuran, 112.5 g of styrene monomer and 1.6 g of n-butyllithium were injected, followed by polymerization for 1 hour. Next, 525 g of 1,3-butadiene monomer was added to the reactor. Injection was carried out for 1 hour to polymerize.

Lastly, 112.5 g of styrene monomer was added and polymerized for 1 hour, and the combined styrene content of 30.5%, butadiene content of 69.5% (vinyl bond content of polybutadiene 39.8%), and styrene-butadiene-styrene living block air having a number average molecular weight of about 60,000 The coalescence was obtained. Living lithium in this polymer was 1.67 mmol per 100 g of polymer.

Synthesis Example 3

Preparation of Living Copolymer

4,500 g of cyclohexane was added to a 2 gallon autoclave reactor, 9 g of tetrahydrofuran, 112.5 g of styrene monomer and 1.7 g of n-butyllithium were injected, followed by polymerization for 1 hour. Next, 525 g of 1,3-butadiene monomer was added to the reactor. Injection was carried out for 1 hour to polymerize.

Finally, 112.5 g of styrene monomer was added and polymerized for 1 hour, whereby the combined styrene content was 30.9%, the butadiene content was 69.1% (vinyl bond content of 41.3% polybutadiene), and the styrene-butadiene-styrene living block air having a number average molecular weight of about 50,000. The coalescence was obtained. Living lithium in this polymer was 2.00 mmol per 100 g of polymer.

Synthesis Example 4

Preparation of Living Copolymer

4,500 g of cyclohexane was added to a 2 gallon autoclave reactor, 9 g of tetrahydrofuran, 112.5 g of styrene monomer and 1.3 g of n-butyllithium were injected, followed by polymerization for 1 hour. Next, 525 g of 1,3-butadiene monomer was added to the reactor. Injection was carried out for 1 hour to polymerize.

Finally, 112.5 g of styrene monomer was added and polymerization was carried out for 1 hour, and the styrene-butadiene-styrene living block air containing 29.9% of bound styrene, 70.1% of butadiene (39.6% of vinyl bond of polybutadiene), and a number average molecular weight of about 100,000 Coalescing was obtained. Living lithium in this polymer was 1.00 mmol per 100 g of polymer.

Synthesis Example 5

Preparation of Living Copolymer

4500g of cyclohexane was charged in a 2 gallon autoclave reactor, 9g of tetrahydrofuran and 1.5g of n-butyllithium were injected, followed by polymerization of 225g of styrene monomer and 525g of 1,3-butadiene monomer simultaneously into the reactor for 1 hour polymerization. . A styrene-butadiene type random copolymer having a styrene content of 29%, a butadiene content of 71% (a vinyl bond content of polybutadiene of 30.5%), and a number average molecular weight of about 60,000 was obtained. Living lithium in this polymer was 1.6 mmol per 100 g of polymer.

Example 1

Hydrogenation reaction

1,050 g of 14.3 wt% living polymer solution obtained in Synthesis Example 2 was placed in a 1 gallon autoclave reactor and heated to 90 ° C. at 450 rpm (rpm). After adding 2 ml of the toluene solution of the catalyst prepared in Synthesis Example 1, the reactor was pressurized with 10 kg / cm 2 of hydrogen so that the hydrogenation reaction was continued for 3 hours. After completion of the reaction, the reactor was cooled and the pressure was reduced to normal pressure, and then the reaction solution was added to the water-vapor mixture. ¹ H-NMR analysis of the obtained hydrogenated polymer showed that the final hydrogenation rate was 100% for the 1,2-polybutadiene portion and 88.1% for the 1,4-polybutadiene portion. In addition, hydrogenation of the styrene unit and decomposition of the polymer did not occur at all.

Example 2

Hydrogenation reaction

1,050 g of the 14.3 wt% living polymer solution obtained in Synthesis Example 2 was placed in a 1 gallon autoclave reactor, and 2 ml of the toluene solution of the catalyst prepared in Synthesis Example 1 was added under the same conditions as in Example 1, and then the reactor was 10 kg / cm 2. The hydrogenation reaction was continued for 3 hours by pressurizing with hydrogen. After completion of the reaction, the reactor was cooled and the pressure was reduced to normal pressure, and then the reaction solution was added to the water-vapor mixture. ¹ H-NMR analysis of the obtained hydrogenated polymer showed that the final hydrogenation rate was 100% for the 1,2-polybutadiene portion and 84% for the 1,4-polybutadiene portion. In addition, hydrogenation of the styrene unit and decomposition of the polymer did not occur at all.

Example 3

Hydrogenation reaction

1,050 g of the 14.3 wt% living polymer solution obtained in Synthesis Example 2 was placed in a 1 gallon autoclave reactor, and 2 ml of the toluene solution of the catalyst prepared in Synthesis Example 1 was added under the same conditions as in Example 1, and then the reactor was 10 kg / cm 2. The hydrogenation reaction was continued for 3 hours by pressurizing with hydrogen. After completion of the reaction, the reactor was cooled and the pressure was reduced to normal pressure, and then the reaction solution was added to the water-vapor mixture. ¹ H-NMR analysis of the obtained hydrogenated polymer showed that the final hydrogenation rate was 100% for the 1,2-polybutadiene portion and 82.5% for the 1,4-polybutadiene portion. Also, no hydrogenation of styrene units or decomposition of polymers occurred.

Example 4

Hydrogenation reaction

1,050 g of the 14.3 wt% living polymer solution obtained in Synthesis Example 2 was placed in a 1 gallon autoclave reactor, and under the same conditions as in Example 1, 2 ml of the toluene solution of the catalyst prepared in Synthesis Example 1 was added, followed by 10 kg / The hydrogenation reaction was continued for 3 hours by pressurization with hydrogen of cm 2. After completion of the reaction, the reactor was cooled and the pressure was reduced to normal pressure, and then the reaction solution was added to the water-vapor mixture. ¹ H-NMR analysis of the obtained hydrogenated polymer showed a final hydrogenation rate of 100% for 1,2-polybutadiene and 83% for 1,4-polybutadiene. In addition, hydrogenation of the styrene unit and decomposition of the polymer did not occur at all.

Example 5

Hydrogenation reaction

1,050 g of the 14.3 wt% living polymer solution obtained in Synthesis Example 2 was placed in a 1 gallon autoclave reactor, and under the same conditions as in Example 1, 2 ml of the toluene solution of the catalyst prepared in Synthesis Example 1 was added, followed by 10 kg / The hydrogenation reaction was continued for 3 hours by pressurization with hydrogen of cm 2. After completion of the reaction, the reactor was cooled and the pressure was reduced to normal pressure, and then the reaction solution was added to the water-vapor mixture. ¹ H-NMR analysis of the obtained hydrogenated polymer showed that the final hydrogenation rate was 100% for the 1,2-polybutadiene portion and 85% for the 1,4-polybutadiene portion. In addition, hydrogenation of the styrene unit and decomposition of the polymer did not occur at all.

Example 6

Hydrogenation reaction

1,050 g of the 14.3 wt% living polymer solution obtained in Synthesis Example 2 was placed in a 1 gallon autoclave reactor, and under the same conditions as in Example 1, 2 ml of the toluene solution of the catalyst prepared in Synthesis Example 1 was added, followed by 10 kg / The hydrogenation reaction was continued for 3 hours by pressurization with hydrogen of cm 2. After completion of the reaction, the reactor was cooled and the pressure was reduced to normal pressure, and then the reaction solution was added to the water-vapor mixture. ¹ H-NMR analysis of the obtained hydrogenated polymer showed that the final hydrogenation rate was 100% for the 1,2-polybutadiene portion and 85% for the 1,4-polybutadiene portion. In addition, hydrogenation of the styrene unit and decomposition of the polymer did not occur at all.

The effect of the present invention is to prevent the formation and decomposition of polymers between catalytically active species in the hydrogenation reaction using a conventional homogeneous catalyst, and satisfies the high hydrogenation reproducibility required for the hydrogenation reaction of a polymer for the purpose of improving the durability and oxidation resistance of the polymer. It is to develop a highly active hydrogenation catalyst. In addition, we have developed a catalyst that is more efficient and stable with a smaller amount of catalyst than conventional homogeneous catalysts, and has developed a catalyst system that avoids the cumbersome process of removing the catalyst residue from the hydrogenated polymer after the reaction.

Claims (8)

Cyclopentadienyl titanium-based hydrogenated catalyst for selectively hydrogenating unsaturated double bonds in conjugated diene units in a living polymer having an olefinic double bond represented by the following general formula (I) R is an organotitanium compound having the structure In the above formula, X ₁ and X ₂ are the same or different from each other and are a substituent selected from the group consisting of a halogen group, a C ₁ to C ₈ alkyl group, a cycloalkyl group, an alkoxy group, a C ₆ or more aryloxy group, a silyl group and a carbonyl group. The cyclopentadienyl titanium-based hydrogenation catalyst according to claim 1, wherein the substituents X ₁ and X ₂ are both chlorine. A method of selectively hydrogenating unsaturated double bonds in conjugated diene units in a living polymer having an olefinic double bond using the catalyst of claim 1 4. The hydrogenation method according to claim 3, wherein the living polymer used for the hydrogenation reaction is a living polymer obtained by polymerizing or copolymerizing at least one conjugated diene in the presence of an organoalkalimetallic polymerization initiator in an inert organic solvent. The hydrogenation method according to claim 4, wherein the organoalkali metal polymerization initiator is an organolithium compound. The hydrogenation reaction temperature is 0 ~ 150 ℃, the pressure of hydrogen is 1 ~ 100 kg / ㎠ and the amount of the organotitanium compound used as a catalyst is in the range of 0.01 ~ 20 mmol per 100g living polymer How to hydrogenate The hydrogenation reaction temperature is 50 ~ 150 ℃, the pressure of hydrogen is 2 ~ 30 kg / ㎠ and the amount of the organotitanium compound used as a catalyst is in the range of 0.05 ~ 5 mmol per 100g living polymer How to hydrogenate The hydrogen contact time is several seconds to 500 hours, preferably 30 to 360 minutes, and the molar ratio of living lithium in the living polymer and titanium in the catalyst is in the range of 2: 1 to 10: 1. How to get