JP2629865B2 - Hydrogenation of olefinically unsaturated polymers - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a method for hydrogenating unsaturated double bonds of olefinically unsaturated polymers.

[Prior art] A polymer having an olefinic double bond can easily undergo chemical modification and crosslinking reaction, but has disadvantages in ozone resistance, oxidation resistance, heat resistance, and the like. . In addition, a polymer having good ozone resistance, oxidation resistance, and heat resistance can be obtained as a saturated polymer by polymerizing an α-olefin using a radical or coordination polymerization catalyst. Limited. A polymer having an olefinic double bond obtained by polymerizing a monomer such as a conjugated diene compound or a cyclic olefin not only significantly improves ozone resistance, oxidation resistance and heat resistance by hydrogenation, but also has α A saturated polymer different from that obtained directly from the polymerization of olefins is obtained.

[Problems to be Solved by the Invention] However, when hydrogenating a polymer having an olefinic double bond, the viscosity of the reaction system increases due to hydrogenation, and it is difficult to hydrogenate due to steric hindrance of the polymer. Underneath required a large amount of catalyst. Further, if hydrogenation is carried out at a high temperature in order to lower the viscosity of the reaction system, the active life of the catalyst is shortened. Therefore, a large amount of the catalyst is required to carry out the hydrogenation at a high temperature. As a result, a complicated catalyst removal treatment step is required to remove the hydrogenation catalyst from the polymer, and if the removal of the catalyst is insufficient, the polymer will have heat resistance, weather resistance, oxidation resistance, etc. There are problems such as lowering of the performance of the, and deterioration of the hue, the development of a high-temperature and highly active hydrogenation catalyst is desired,
Several methods have been proposed (for example, JP-B-63-48).
No. 41, JP-B-63-5401, JP-B-63-5402, JP-A-61
No. -28507).

The object of the present invention is to use a small amount of a catalyst and hydrogenate an olefinically unsaturated polymer at a high temperature to obtain weather resistance, oxidation resistance,
An object of the present invention is to provide a method for obtaining a polymer having excellent heat resistance and hue.

Means and Action for Solving the Problems The present inventors have studied an olefinically unsaturated polymer (hereinafter referred to as an olefinically unsaturated polymer) selected from a conjugated diene (co) polymer and a norbornene (co) polymer. As a result of intensive studies on the method of hydrogenating unsaturated double bonds in a highly active state at high temperature, a specific benzyl compound of titanium, a specific benzyl derivative compound of titanium and a specific titanacycloalkane compound At least one selected from the group consisting of at least one selected from the group consisting of organometallic compounds belonging to Groups I to III of the periodic table. The inventors have found that a heavy bond can be hydrogenated, and have completed the present invention.

That is, the method for hydrogenating an olefinically unsaturated polymer of the present invention comprises the steps of: (A) dissolving an olefinically unsaturated polymer in a hydrocarbon solvent; Wherein X ₁ , X ₂ , X ₃ and X ₄ are the same or different groups,
Respectively (In this case, R ₁ , R ₂ and R ₃ are each a hydrogen atom or C ₁
A ~C alkyl group _4), Y is chlorine atom, bromine atom or fluorine atom, n is 0 or 1, Cp is a cyclopentadienyl group, Z is a divalent C ₄ at least one selected from titanium compounds represented by -C ₁₂ hydrocarbon group], (B) at least one member selected from the periodic table I~III group organometallic compounds, consisting essentially of the catalyst Contacting with hydrogen in the presence to hydrogenate the unsaturated double bond of the olefinically unsaturated polymer.

It is known that the titanium compounds (a), (b) and (c) according to the present invention are thermally stable and can be easily isolated, unlike ordinary alkyl compounds of titanium. [DGH Ballard, PWVan Lienden, Makromol.Chem.
154 177 (1972); DAStraus, RHGrubbs, Organometalli
cs 1 1658 (1982); HJ Deliefde Meijer, F. Jellnek, Ino
rg.Chim, Acta. 4 651 (1970 )].

The aforementioned titanium compounds (a) and (b), which are the components (A) of the hydrogenation catalyst, are characterized in that their benzyl group or benzyl derivative is simultaneously bonded to a titanium atom by a CH bond with a —CH ₂ — group. Has thermal stability and high activity hydrogenation catalysis different from ordinary monodentate alkyl and aryl groups due to the bidentate coordination of π bond. Further, the other titanium compound (c) of the component (A) also has bidentate coordination to the titanium atom to form titanacycloalkane, and thus has a thermally stable and highly active hydrogenation catalytic action.

Specific examples of the titanium compound (a) include tetrabenzyl titanium, tetra (4-methylbenzyl) titanium, tetra (4-ethylbenzyl) titanium, tetra (4-n-butylbenzyl) titanium, tribenzyltitanium fluoride, Benzyl titanium chloride, tribenzyl titanium bromide, tetra (3,
5-dimethylbenzyl) titanium, tetra (3,5-di-
tert-butylbenzyl) titanium, bisbenzylbis (4-methylbenzyl) titanium, bisbenzylbis (3,5-dimethylbenzyl) titanium, and specific examples of the titanium compound (b) include bis (η-cyclopentane). Dienyl) bisbenzyltitanium, bis (η-cyclopentadienyl) bis (4-methylbenzyl) titanium, bis (η-cyclopentadienyl) bis (3,5
-Dimethylbenzyl) titanium.

The titanacycloalkane compound of the titanium compound (c) is obtained by reacting bis (η-cyclopentadienyl) titanium dichloride with trimethylaluminum to form a carbene complex of titanium with 3,3-dimethylbutene-1,3-methyl-. It is obtained by adding butene-1, isobutylene, cyclopentene, norbornene, styrene and the like. Specific examples thereof include bis (η-cyclopentadienyl) titana-β-t-
Butyl-cyclobutane, bis (η-cyclopentadienyl) titana-β-i-
Propyl-cyclobutane, bis (η-cyclopentadienyl) titana-β-phenyl-cyclobutane, bis (η-cyclopentadienyl) titana-β, β-
There are dimethyl-cyclobutane, 3,3-bis ([eta] -cyclopentadienyl) -3-titanatricyclononane, and bis ([eta] -cyclopentadienyl) titanacyclocycloheptane.

In the present invention, one or more selected from these titanium compounds is used, and the use amount thereof is preferably in the range of 0.005 to 50 mmol per 100 g of the olefinically unsaturated polymer. If the amount is less than 0.005 mmol, the hydrogenation efficiency is poor, and if it exceeds 50 mmol, it is necessary to remove catalyst residues from the polymer.

As the organometallic compounds of Groups I to III of the periodic table, which are the component (B) of the hydrogenation catalyst, organolithium compounds, organosodium compounds, organomagnesium compounds, organozinc compounds and organoaluminum compounds are preferred.

N-propyl lithium as the organic lithium compound,
n-butyllithium, sec-butyllithium, tert-butyllithium, n-bexyllithium, phenyllithium, tolyllithium, benzyllithium, 1,4-dilithiobutane, 1,4-dilithio-1,1,4,4- Tetraphenylbutane, 1,3 or 1,4-bis (1-lithio-1,3-dimethylpentyl) benzene, 1,3 or 1,4-bis (1-lithio-3-methylpentyl) benzene, etc. are used. Can be
Furthermore, polybutadienyl lithium, polyisoprenyl lithium, polystyryl lithium, styrene obtained by polymerizing 1,3-butadiene, isoprene, styrene and a mixture of styrene / 1,3 butadiene with an organic lithium compound as an initiator. -Butadiene copolymer A high molecular weight organic lithium compound such as anionic lithium can also be used.

As the organic sodium compound, butyl sodium, aryl sodium, aluminum sodium, benzyl sodium, tolyl sodium and the like are used.

As the organic magnesium compound, diethyl magnesium, dibutyl magnesium, dihexyl magnesium, butylhexyl magnesium, dioctyl magnesium, ethyl magnesium chloride, butyl magnesium chloride and the like are used.

As the organic zinc compound, diethyl zinc, dibutyl zinc, dihexyl zinc and the like are used.

As the organic aluminum compound, trimethylaluminum, triethylaluminum, tri-i-butylaluminum, trihexylaluminum, diethylaluminum hydride, dibutylaluminum hydride, diethylaluminum fluoride, diethylaluminum chloride, dibutylaluminum chloride,
Sesquiethyl aluminum chloride, ethyl aluminum dichloride and the like are used.

In the present invention, one or more kinds selected from the organometallic compounds of Groups I to III of the periodic table are used, and the usage rule is 0.5 to 50 mol, preferably 0.5 to 50 mol, per mol of the titanium compound. It is in the range of 1.0 to 15 moles. If the amount is less than 0.5 mol or more than 50 mol, the activity of hydrogenation becomes insufficient.

The invention also relates to the catalyst itself as described above. The preferred composition range of the catalyst is as described above.

The olefinically unsaturated polymers hydrogenated according to the present invention include polybutadienes of various microstructures, such as cis 1,4-polybutadiene, high trans polybutadiene, low cis 1,4-polybutadiene, medium and high vinyl polybutadiene; Polysoprene of various microstructures such as 1,4-polyisoprene, 3,4-polyisoprene, high trans 1,4-polyisoprene; random type emulsion polymerization and solution polymerization styrene-butadiene copolymer; AB- A,
A-B, B-A- B-A, A-B-A-B-A, (A-B) m X ( provided that A: styrene, p- methyl styrene, alpha-methyl styrene, tert- butyl styrene Ken , A homo- or copolymer of an aromatic vinyl compound selected from vinyl naphthalene, etc., and a homo- or copolymer of a conjugated diene compound selected from B: butadiene, isoprene, 2,3-dimethylbutadiene, 1,3-pentadiene, etc. blocky polymer represented by the general formula, such as coalescence); butadiene-isoprene random copolymer; polybutadiene - polyisoprene block copolymer; number-average molecular weight, such as polynorbornene 1000 to ⁶ of polymers.

The hydrogenation reaction of the present invention may be carried out in a state in which the olefinically unsaturated polymer is dissolved in a hydrocarbon solvent, or may be subsequently produced after polymerization to produce an olefinically unsaturated polymer in a hydrocarbon solvent. it can.

Examples of the hydrocarbon solvent include aliphatic hydrocarbons such as pentane, hexane, heptane, and octane; cyclopentane,
Alicyclic hydrocarbons such as methylcyclopentane and cyclohexane; and aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene can also be used. These hydrocarbon solvents may contain ethers such as diethyl ether, tetrahydrofuran, and dibutyl ether in a range of 20% by weight or less.

In the hydrogenation reaction of the present invention, the above-mentioned hydrogenation catalyst is added under an atmosphere of an inert gas such as nitrogen or argon or hydrogen at a polymer concentration of 1 to 30% by weight, preferably 3 to 20% by weight,
Then pressurized圧装enter the city the hydrogen pressure of 1~50kg / cm ^2, 20~15
It is carried out at a temperature of 0 ° C, preferably 50-120 ° C.

The hydrogenation reaction time of the present invention is 1 minute to 10 hours, and the reaction time is shorter as the amount of the hydrogenation catalyst is larger and the hydrogen pressure is higher.

The hydrogenation reaction of the present invention can be carried out by either a batch method or a continuous method. The process of the present invention results in polymers having at least 80%, preferably at least 90%, of the olefinically unsaturated double bonds hydrogenated. However, the hydrogenation of aromatic double bonds, if present, is less than 5% and is substantially not hydrogenated. In addition, in the hydrogenation reaction of the present invention, molecular cleavage of the polymer hardly occurs.

The polymer hydrogenated by the method of the present invention removes catalyst residues from the polymer solution as needed, adds an antioxidant, and throws the polymer solution into hot water with steam,
A method in which a solvent is recovered by steam distillation and a polymer is recovered in a crumb form; a method in which a polymer solution is flowed on a heating roll and the solvent is evaporated to recover the polymer, or a method in which the polymer solution is recovered using alcohol, acetone, or the like. The polymer can be isolated from the polymer solution by a method in which the polymer is poured into a polar solvent, and the polymer is precipitated and recovered. In the hydrogenation method of the present invention, the amount of catalyst used is small, so the catalyst residue is small,
Further, since the catalyst residue has little effect on the weather resistance and heat resistance of the polymer, the step of removing the catalyst can be omitted.

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples.
The present invention is not limited to these.

The vinyl aromatic hydrocarbon content of the copolymer containing a vinyl aromatic hydrocarbon in the examples was determined by a nuclear magnetic resonance method (NMR) at 100 MHZ. Conjugated diene polymer
The 1,2-bond content was measured by the Morero method using an infrared absorption spectrum. For example, in the case of a betadiene-based polymer, the hydrogenation rate of the unsaturated double bond of the olefinically unsaturated polymer is determined by the absorption peak based on the side-chain double bond at around 4.9 and 5.4 ppm and the main chain at around 5.4 ppm. The reduction ratio of the absorption peak due to the heavy bond was measured and determined by nuclear magnetic resonance (NMR) at 100 MHz.

Examples 1 to 5 Polymers shown in Table 1 obtained by polymerizing monomers such as styrene, 1,3-butadiene and isoprene using n-butyllithium as an initiator in cyclohexane were adjusted to a concentration of 12% by weight with cyclohexane. did. 2500 g of this polymer solution was charged into an autoclave equipped with a stirrer (5), and the inside of the reaction system was replaced with hydrogen gas. Then, 1.1 mmol of tetrabenzyltitanium and 3.3 mmol of triethylaluminum were charged into an autoclave, hydrogen pressure was 9 kg / cm ² , and reaction temperature was 8
The hydrogenation reaction was performed at 0 ° C. with stirring for 1 hour.

The reaction solution was returned to normal temperature and normal pressure, and 5 mmol of bis (2-ethylhexyl) ester produced from phosphorus was added.
-Di-tert-butyl-p-cresol per 100 g of polymer
0.5 g was added, and then the polymer solution was taken out by an autoclave and put into a temperature at which steam was blown,
The polymer was obtained by removing cyclohexane. This polymer
Dry on a hot roll at 110 ° C. for 15 minutes. The result is
It is shown in the table.

(Note 1) A: polystyrene-polybutadiene-polystyrene block copolymer, (bonded styrene content 35% by weight, molecular weight of polystyrene 15,000, molecular weight of polybutadiene 59000,
1,2-bond 35%. B) polystyrene-polybutadiene-block copolymer,
(Bound styrene content 30% by weight, molecular weight of polystyrene part
20000, molecular weight of polybutadiene part 46600, 1,2-bond 40
%. C: polybutadiene (butadiene in cyclohexane
Polybutadiene having a molecular weight distribution of 50% with 1,2 bonds and a molecular weight of 360,000, which is polymerized with Li and terminated with SiCl ₄ and has a bimodal molecular weight distribution. D) polybutadiene (1) -polybutadiene (2) -polystyrene block copolymer, (molecular weight of polystyrene part)
15000, molecular weight of polybutadiene (1) part 30,000,1,2-bond 12%, molecular weight of polybutadiene (2) part 58,000,1,2-
45% binding. E) Butadiene / isoprene random copolymer (molecular weight 12
000, 70 mol% of butadiene. (Note 2) Indicates the hydrogenation rate of the olefinically unsaturated double bond.

Comparative Example 1 The same operation as in Example 1 was carried out except that bis (η-cyclopentadienyl) diethyltitanium was used in place of 1.1 mmol of tetrabenzyltitanium used in Example 1. As a result, the hydrogenation rate of the polymer was 70%.

Comparative example 2 It carried out similarly to Example 1 except not using the triethyl aluminum used in Example 1. As a result, the hydrogenation rate of the polymer was 80%.

Example 6 The same operation as in Example 4 was carried out except that 6.6 mmol of n-butyllithium was used instead of 3.3 mmol of triethylaluminum used in Example 4. As a result, the hydrogenation rate of the polymer was 98%.

Except that was used instead of triethylaluminum 3.3 mmol MgBu ₂ · 1 / 4AlEt ₃ 1.5 mmol used in Example 7 Example 4 was prepared as in Example 4. As a result, the hydrogenation rate of the polymer was 97%.

Example 8 Example 8 was carried out in the same manner as in Example 4 except that bis (η-cyclopentadienyl) dibenzyltitanium was used instead of tetrabenzyltitanium used in Example 4. As a result, the hydrogenation rate of the polymer was 96%.

Example 9 2000 g of cyclohexane, 500 g of 1,3-butadiene and 4 g of tetrahydrofuran were charged into an autoclave of 7, and the temperature in the reaction system was adjusted to 35 ° C., and then n-butyllithium was added.
The polymerization was carried out for 30 minutes at an increased temperature of up to 100 ° C. with the addition of mmol. The addition rate to the polymer was 99.5%.
To this active polymer solution, 5 mmol of bis (-ηcyclopentadienyl) titanabicycloheptane was added, and a hydrogenation reaction was performed at 90 ° C for 1 hour at a hydrogen pressure of 12 kg / cm ₂ . The hydrogenation rate of the polymer was 95%.

Example 10 The same operation as in Example 1 was carried out except that polynorbornene having a molecular weight of 568,000 was used instead of the polymer polystyrene-polybutadiene-polystyrene block polymer of Example 1.
The hydrogenation rate of the polymer was 92%.

[Effect of the Invention] The present invention relates to a thermally stable organotitanium compound and a periodic table I
A catalyst system consisting of an organometallic compound of group III to III, whereby the unsaturated double bond of the olefinically unsaturated polymer is hydrogenated at a high temperature under a low pressure with a small amount of a catalyst and weather resistance and oxidation resistance And a polymer having excellent heat resistance and hue.

Claims (1)

(57) [Claims] 1. An olefinically unsaturated polymer selected from a conjugated diene (co) polymer and a norbornene (co) polymer in a hydrocarbon solvent, comprising: Wherein X ₁ , X ₂ , X ₃ and X ₄ are the same or different groups,
Respectively (In this case, R ₁ , R ₂ and R ₃ are each a hydrogen atom or C ₁
A ~C alkyl group _4), Y is chlorine atom, bromine atom or fluorine atom, n is 0 or 1, Cp is a cyclopentadienyl group, Z is a divalent C ₄ at least one selected from titanium compounds represented by -C ₁₂ hydrocarbon group], (B) at least one member selected from the periodic table I~III group organometallic compounds, consisting essentially of the catalyst A method for hydrogenating an olefinically unsaturated polymer, comprising contacting hydrogen with hydrogen in the presence to hydrogenate the unsaturated double bond of the olefinically unsaturated polymer.