JPH0579081B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for hydrogenating diene polymers,
More specifically, the present invention relates to a method for hydrogenating a diene polymer having a hydrogen group at its terminal, which has a high hydrogenation rate and can prevent the hydrogen groups from being cut or separated. [Prior Art and Problems to be Solved by the Invention] Diene polymers having hydrogen groups at the molecular ends, such as butadiene, isoprene, or chloroprene polymers, are heavily used as raw materials for polyurethane. These polymers are generally hydrogenated, for example, in the presence of a catalyst, for the purpose of improving their weather resistance. As hydrogenation catalysts used in such hydrogenation reactions, catalysts in which nickel, palladium, ruthenium or rhodium is supported on a carrier such as silica, alumina, diatomaceous earth, or carbon are known. However, the nickel catalyst has a low hydrogenation rate of the polymer, while the palladium, ruthenium and rhodium catalysts have the problem of eliminating the terminal hydrogen group of the polymer. The purpose of the present invention is to solve such conventional problems,
The object of the present invention is to provide a method capable of hydrogenating a polymer having a hydrogen group at a high hydrogenation rate without cutting or separating the hydrogen groups of the polymer. [Means for solving the problem] As a result of extensive research focusing on the composition of the catalyst used in the hydrogenation reaction, the present inventors discovered that a single metal was supported on a carrier as in the past. The present invention was completed based on the discovery that the above object can be achieved by using a catalyst made of two predetermined metals supported instead of a catalyst. That is, the method for hydrogenating a diene polymer of the present invention involves hydrogenating a diene polymer having hydrogen groups in the presence of a catalyst comprising two metals of Group Group of the periodic table, including nickel, as a carrier. It is characterized by [Specific Description] First, the diene polymer to which the hydrogenation method of the present invention is applied is not particularly limited as long as it has a hydrogen group, but in particular, a diene polymer that has a hydroxyl group at both ends of the molecule. It is preferable that
Specifically, the following formula:

embedded image (wherein R represents a hydrogen atom, a chlorine atom or a methyl group, and n represents an integer from 5 to 300), ie, butadiene, chloroprene or isoprene polymers. Next, a catalyst with a novel composition, which is the main feature of the method of the present invention, will be explained. That is, as mentioned above, the hydrogenation catalyst used in the present invention has a carrier containing compounds belonging to groups of the periodic table, that is, Fe, Ni, Co, Ru, Rh, Pd, Os, Ir, and Pt.
Of these, two types of metals including Ni are supported. Among these, Ru, Ph, Pd, or Pt are particularly suitable metals in combination with Ni. The material of the carrier is not particularly limited, but
Examples include silica, alumina, carbon, silica, alumina, and diatomaceous earth.
In addition, the amount of these metals supported is usually 100
Nickel is 0.05 to 500 parts by weight,
The content is preferably 0.1 to 100 parts by weight, and the content of one of the group metals excluding nickel is set to 0.05 to 500 parts by weight, preferably 0.1 to 100 parts by weight. When producing such a catalyst, a predetermined amount of Ni and one of the group metals excluding Ni may be simultaneously supported on a predetermined carrier, while a carrier supporting only Ni and a group metal other than Ni may be simultaneously supported on a predetermined carrier. A carrier supporting only one of the metals may be mixed at a predetermined ratio. In particular, the catalyst obtained by the latter method has high activity and is more preferable. Next, the hydrogenation method of the present invention using such a catalyst will be described. First, for example, the above-described diene polymer, catalyst, and solvent are placed in a pressure container. Solvents used at this time include aliphatic hydrocarbons such as pentane, hexane, heptane, and octane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, and methylcyclohexane; methanol, ethanol,
Examples include alcohols such as isopropanol. Thereafter, hydrogen is introduced into this container to carry out a hydrogenation reaction. At this time,
The reaction temperature is 30-300℃, preferably 100-200℃,
Pressure is 10-200Kg/cm ² G, preferably 30-100
Kg/cm ² G, reaction time 0.1-100 hours, preferably
Set each time from 0.5 to 10 hours. After the reaction is completed, the reaction product is extracted from the container, the catalyst is separated, and the solvent, unreacted diene polymer, and light boiling point components are distilled off from the resulting liquid to obtain the desired hydrogenated polymer. [Example] (1) Preparation of catalyst Catalysts A to E according to the present invention were prepared as follows. Catalyst A Catalyst A was prepared by mixing palladium (5% by weight) supported carbon (manufactured by Nippon Engelhard Co., Ltd.) and nickel (45% by weight) supported diatomaceous earth (manufactured by JGC Chemical Co., Ltd.) at a weight ratio of 2:8. I got it. Catalyst B Catalyst B was prepared by mixing rhodium (5% by weight) supported carbon (manufactured by Nippon Engelhard Co., Ltd.) and nickel (45% by weight) supported diatomaceous earth (manufactured by JGC Chemical Co., Ltd.) at a weight ratio of 2:8. I got it. Catalyst C 1 g of PdCl ₂ and 2.3 g of Ni(NO ₃ )/6H ₂ O were each made into aqueous solutions, each aqueous solution was dropped into 1N ammonia water to form a precipitate, and the resulting precipitate was collected by filtration. After air drying, it was dried at 110°C for 2 hours.
After thoroughly mixing the two types of powder thus obtained and 95 g of γ-alumina (manufactured by Mizusawa Chemical Co., Ltd.) in a mortar,
Catalyst C was obtained by heating at 550°C for 2 hours. When the amount of each metal supported on this catalyst C was measured by atomic absorption spectrophotometry, it was found that Ni was 4.32% by weight and Pd was 0.41% by weight.
It was hot. Catalyst D: Ruthenium (5% by weight) supported carbon (made by Nippon Engelhard Co., Ltd.) and nickel (45% by weight) supported diatomaceous earth (made by JGC Scientific Co., Ltd.) were mixed at a weight ratio of 2:8 to prepare catalyst D. I got it. Catalyst E: Catalyst D was prepared by mixing platinum (5% by weight) supported carbon (manufactured by Nippon Engelhard Co., Ltd.) and nickel (45% by weight) supported diatomaceous earth (manufactured by JGC Chemical Co., Ltd.) at a weight ratio of 2:8. I got it. Furthermore, in the comparative example, the following five types of catalysts F
~J was used. Catalyst F: Nickel (45% by weight) supported diatomaceous earth (manufactured by JGC Chemical Co., Ltd.) Catalyst G: Palladium (5% by weight) supported on carbon (manufactured by Nippon Engelhard Co., Ltd.) Catalyst H: Rhodium (5% by weight) supported Carbon (manufactured by Nippon Engelhard Co., Ltd.) Catalyst I: Carbon supported on ruthenium (5% by weight) (manufactured by Nippon Engelhard Co., Ltd.) Catalyst J: Carbon supported on platinum (5% by weight) (manufactured by Nippon Engelhard Co., Ltd.) (2) Hydrogenation reaction of diene polymer A diene polymer having hydroxyl groups at both ends as indicated, a catalyst, and a solvent are placed in a stainless steel pressure vessel with an internal volume of 1 equipped with a stirrer and a heater.
Next, hydrogen gas was introduced, the temperature was raised over 60 minutes, and then hydrogenation was carried out under the indicated conditions. Thereafter, air was blown onto the outer surface of the container to lower the temperature, and the reaction product was extracted. Then, the catalyst was separated, and the solvent, unreacted diene polymer, and light boiling point components were distilled off from the liquid using a thin film evaporator to obtain the desired hydrogenated polymer. This distillation process includes a first step of 30 minutes at 50°C and 20mmHg, and a
The second stage was carried out for 1 hour at 2 mmHg and 2 mmHg. In this step, the hydrogenation rate (%) of the diene polymer, i.e., the bromine number of the diene polymer before hydrogenation - the bromine number of the diene polymer after hydrogenation / the diene polymer before hydrogenation. The bromine number x 100 was calculated, and the results are shown in the table together with the hydroxyl group content (meq/g) of the diene polymer after hydrogenation.

【table】

[Table] [Effects of the Invention] As is clear from the above explanation, the method of the present invention uses a novel catalyst supporting two types of metals including nickel, so that the hydrogenation rate of diene polymers is extremely high. In addition to being high in hydroxyl content, there is almost no change in the hydroxyl group content before and after the hydrogenation reaction. That is, it has the advantage that cleavage and separation of hydroxyl groups hardly occur. Therefore, its industrial value is extremely great, for example, in the field of producing raw materials for polyurethane.

Claims (1)

[Scope of Claims] 1. Among Group Group metals of the periodic table, including nickel. 2.
A method for hydrogenating a diene polymer, comprising hydrogenating a diene polymer having a hydroxyl group in the presence of a catalyst comprising a species supported on a carrier. 2. The hydrogenation method according to claim 1, wherein the catalyst is a mixture of a carrier supporting nickel and a carrier supporting one of group metals other than nickel. 3. The hydrogenation method according to claim 1, wherein one of the group metals contained in the catalyst, excluding nickel, is palladium, rhodium, ruthenium, or platinum. 4. The hydrogenation method according to claim 1, wherein the diene polymer has hydrogen groups at both ends of the molecule. 5 Claims in which the diene polymer is represented by the following formula: [Chemical formula] (wherein R represents a hydrogen atom, a chlorine atom, or a methyl group, and n represents an integer from 5 to 300) The hydrogenation method according to item 1.