JPS6335642B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for hydrogenating a conjugated diene polymer using a Pd catalyst with improved catalytic activity. Conventionally, as a catalyst for hydrogenating carbon-carbon double bonds in conjugated diene polymers, supported catalysts in which metals from the periodic table group are supported on porous supports such as carbon, silica, and alumina have been commonly used. It is used. By the way, when hydrogenating unsaturated bonds in a polymer, in the case of styrene-butadiene (random or block) copolymers, if the benzene nucleus of the styrene is also hydrogenated, the polymer loses its rubber-like properties. In addition, in the case of acrylonitrile-butadiene (random or alternating) copolymers, reduction of the nitrile group significantly reduces oil resistance, and the inherent properties of the polymer are affected by hydrogenation. If this were to occur, there would be no point in modifying the polymer. Therefore, selectively only the double bonds of the conjugated diene moieties in the polymer must be hydrogenated. Catalytic metals with such selectivity include Pt,
Precious metals such as Pd are often used. However, since these noble metals are expensive, it is desirable to be able to selectively hydrogenate them using as little amount as possible. Furthermore, when hydrogenating high molecular weight polymers, the hydrogenation reaction is difficult to proceed due to the high viscosity of the reaction system, and a large amount of catalyst must be used, which requires a catalyst with high activity and high selectivity. There is. As a result of extensive research, the present inventors found that when a conjugated diene polymer is hydrogenated using a catalyst in which Pd and other metals and/or non-metals are simultaneously supported on a carrier, the catalytic metal is The present invention was completed by discovering that Pd has extremely high activity and selectivity compared to Pd alone. Therefore, an object of the present invention is to provide a Pd-based catalyst that has high activity in the hydrogenation of conjugated diene-based polymers and can selectively hydrogenate carbon-carbon double bonds in polymer chains or side chains. It's about doing. The purpose of the present invention is to use Au, B, Al, Ga, Si, Pd, etc. as a catalyst in the hydrogenation of conjugated diene polymers using a porous powdery and/or granular carrier such as carbon, silica, and alumina. Ge, Sb,
This is achieved by using a catalyst supported with at least one selected from Mo, Te, W and Re. The catalyst used in the present invention is a porous granular and/or powder carrier that is commonly used, such as silica, silica alumina, alumina, diatomaceous earth, activated carbon, or carbon black used for rubber or color. At the same time, Au,
B, Al, Ge, Si, Ge, Sb, Mo, Te, W and
At least one species selected from Re is supported. The above-mentioned metal and/or non-metal support can be supported by a conventional support method and is not limited in any way. The support can be carried out by immersing the carrier in an aqueous solution of salts such as hydroxides, acid chlorides, sulfates, carbonates, etc. The amount of Pd supported on the carrier is 0.001 to 30% by weight per carrier, preferably
It is 0.01-10% by weight. If the amount of supported Pd is too small, the amount of catalyst supported on the carrier used during the reaction will be too large, increasing the viscosity of the system, making stirring difficult, and making the catalyst ineffective. On the other hand, if the supported amount is too large, the dispersion of the metal and/or nonmetal on the carrier will be poor, and the particle size of the metal and/or nonmetal will also increase, resulting in a decrease in catalytic activity. The atomic ratio of the metal or nonmetal element supported together with Pd to Pd is in the range of 0.001 to 50, preferably 0.005 to 10. The amount of the carrier-supported catalyst used is in the range of 5 to 2000 ppm, preferably 10 to 1000 ppm, based on the amount of Pd per polymer.
Although it is possible to use more than 2000ppm, it is not economical. In the conjugated diene polymer used in the present invention, the conjugated diene monomer is 1,3-butadiene, 2,3
- One or more monomers selected from dimethyl butadiene, isoprene, 1,3-pentadiene, etc., 10 to 100% by weight of the total monomers, and/or ethylenically unsaturated monomers such as unsaturated nitriles, such as acrylonitrile , methacrylonitrile, monovinylidene aromatic hydrocarbons such as styrene, alkylstyrene (o-,
unsaturated carboxylic acids or their esters, such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid or methyl acrylate, ethyl acrylate, butyl acrylate; , 2-ethylhexyl acrylate, methyl methacrylate, etc., one or more monomers selected from vinyl pyridine and vinyl esters such as vinyl acetate, etc., with 0 to 90% of the total monomers.
% by weight of a conjugated diene polymer and/or a conjugated diene copolymer. These (co)polymers can be processed by emulsion polymerization, solution polymerization,
It may be produced by any polymerization method such as bulk polymerization, and specifically, polyisoprene, polybutadiene, styrene-butadiene (random or block) copolymer, acrylonitrile-butadiene (random or alternating) copolymer. etc. Although the hydrogenation reaction can be carried out with the polymer as it is, good results are obtained when the polymer is dissolved in a solvent and carried out in a solution state. The concentration of the polymer solution is 1 to 70% by weight,
Preferably it is 1 to 40% by weight. The solvent is not particularly limited as long as it does not adversely affect the catalyst and dissolves the polymer to be hydrogenated, but examples include benzene, toluene, xylene, hexane, cyclohexane, tetrahydrofuran, acetone, methyl ethyl ketone, cyclohexanone, ethyl acetate, etc. is commonly used. Polymers produced by solution polymerization can be hydrogenated as polymer cements. The hydrogenation reaction is carried out in an autoclave, and the reaction temperature is 0-300°C, preferably 20-150°C.
It is. A temperature of 150° C. or lower is preferred in order to allow the selective hydrogenation reaction to proceed and to suppress undesirable side reactions. Although the hydrogen pressure is not particularly limited, it is usually carried out in the range of atmospheric pressure to 300 Kg/cm ² , preferably 5 to 200 Kg/cm ² . 300Kg/cm2 or ^more is not practical from the standpoint of equipment and operation. Hydrogenated polymers have excellent weather resistance, ozone resistance, heat resistance, cold resistance, etc., and can be used in a wide range of fields. The present invention will be specifically explained below using Examples.
The hydrogenation rate of the polymer was determined by the iodine value method. In the following examples, the amount of catalyst means the total amount of carrier and catalyst. Example 1 Pd alone and Pd were added to activated carbon as a carrier.
At the same time, Au, B, Al, Ga, Si, Ge, Sb, Mo,
Acrylonitrile-butadiene copolymer was hydrogenated using a catalyst supporting Te, W, and Re. In the case of a combination system, the atomic ratio of each element to Pd was 1:1. In both cases, the amount of Pd per carrier was 1% by weight. (Preparation of catalyst) Except for using HAuCl ₄ as the Au source, each chloride was used as the source of each element. Activated carbon was immersed in these aqueous solutions, thoroughly impregnated into the activated carbon, and reduced with formalin-caustic soda. It was used as a catalyst supported on a carrier. (Hydrogenation method) In an autoclave with a capacity of 100 ml, add 3 g of acrylonitrile-butadiene random copolymer to 17 g of acetone (bonded acrylonitrile amount: 41.1% by weight,
A solution containing ML _(1+4,100 °C = 53, abbreviated as NBR) and 0.075 g of the above supported catalyst (equivalent to 2.5 parts by weight per 100 parts by weight of polymer) were charged, and after purging the system with nitrogen, 50 kg of hydrogen was added. The hydrogenation reaction was carried out at 50° C. for 4 hours under pressure of /cm ² . The results are shown in Table 1. No reduction of the nitrile group was observed in any case.

【table】

[Table] Example 2 A catalyst was prepared in the same manner as in Example 1, using Al, Re, and Si as metals or non-metals supported on activated carbon together with Pd so that the atomic ratio with Pd was 1:1. . Chlorides of each element were used as element sources. To examine the activity of these catalysts, a volume of 100
3g in 27g of cyclohexane in a ml autoclave
of polybutadiene (cis-1.4 content 98%,
A solution containing ML _(1+4,100 °C=40) was charged, and after purging with nitrogen, the pressure was increased to 50 kg/cm ² with hydrogen, and hydrogenation was performed at 90°C for 4 hours. Catalyst amount is 3 parts by weight/polymer
It is 100 parts by weight. The results are shown in Table 2.

【table】

Claims (1)

[Claims] 1 In a method of hydrogenating carbon-carbon double bonds of a conjugated diene polymer, porous powder and/or
Or Au, B, Al, Ga,
1. A method for hydrogenating a conjugated diene polymer, comprising using a catalyst supported on at least one selected from Si, Ge, Sb, Mo, Te, W and Re.