JPH0579082B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for producing a hydrogenated polymer, and more specifically, a method for producing a hydroxyl additive of a diene polymer having a hydroxyl group, and the present invention relates to a method for producing a hydrogenated polymer. This invention relates to a method for efficiently fractionating polymers. [Prior Art] Diene polymers having a hydroxyl group at the molecular end, 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, in order to improve their weather resistance and heat resistance. When producing such hydrogenated polymers, a catalyst consisting of nickel, palladium, ruthenium or rhodium supported on a carrier such as silica, alumina, diatomaceous earth or carbon is usually used.
The polymer is hydrogenated in the presence of the catalyst in a solvent such as an aliphatic hydrocarbon or alicyclic hydrocarbon, the catalyst is separated from the obtained hydrogenation product solution, and the solvent is distilled off from the furnace liquid. A method of obtaining the desired hydrogenated polymer is adopted. [Problems to be Solved by the Invention] However, in the above method, in addition to the target hydrogenated polymer, i.e., highly hydrogenated polymer, there are some things obtained after distilling off the solvent. , unhydrogenated polymer, and low hydrogenated polymer coexist, and it is extremely difficult to separate these, so the quality of the hydrogenated polymer has to be relatively low. . Therefore, in the past, in order to increase the yield of the desired hydrogenated polymer, the hydrogenation reaction conditions were made more severe, resulting in process disadvantages. The present invention solves the conventional problems and provides a method for producing hydrogenated polymers, which includes a step of hydrogenating a diene polymer having a hydroxyl group and then efficiently fractionating the highly hydrogenated polymer by a simple means. The purpose is to provide a manufacturing method. [Means for Solving the Problems] In the course of intensive research to achieve the above object, the inventor of the present invention mixed the hydrogenated product solution obtained after the completion of the hydrogenation reaction with alcohol, and allowed it to stand still. Then, in the mixed solvent system of the solvent and alcohol used for the reaction, a two-layer solution with different color tones, that is,
The fact that the light-colored solution of the desired highly hydrogenated polymer and the dark-colored solution containing the unhydrogenated polymer, low hydrogenated polymer, and catalyst are separated into upper and lower phases due to the difference in specific gravity between the two solutions. This led to the completion of the present invention. That is, the method for producing a hydrogenated polymer of the present invention is characterized by comprising a step of catalytically hydrogenating a diene polymer containing a hydroxyl group in a solvent and treating the obtained hydrogenated product solution with alcohol. shall be. [Specific Description] First, in the method for producing a hydrogenated polymer of the present invention, the starting material diene polymer is not particularly limited as long as it has a hydroxyl group. It is preferable to have a hydroxyl group at the terminal, specifically, the following formula:

Examples include those represented by the formula (wherein R represents a hydrogen atom, a chlorine atom or a methyl group, and n represents an integer from 5 to 300), that is, butadiene, chloroprene or isoprene polymers. The solvent used at this time is not particularly limited, and suitable examples include aliphatic hydrocarbons such as pentane, hexane, heptane, and octane; and alicyclic hydrocarbons such as cyclopentane, cyclohexane, and methylcyclohexane. It can be given as something. Furthermore, catalysts used in the reaction include, for example, Ni, Pd and
It is useful to use one type of Rh or two types containing Ni. Next, the steps for producing the hydrogenated polymer of the present invention will be explained step by step. First, for example, the above-described diene polymer, catalyst, and solvent are placed in a pressure container. Thereafter, hydrogen is introduced into this container to carry out a hydrogenation reaction. At this time, the reaction temperature is 30-300°C, preferably 100-200°C, the pressure is 10-200Kg/ ^cm2G , preferably 30-100Kg/ ^cm2G , and the reaction time is 0.1-100 hours, preferably 0.5 Set each to ~10 hours. After the reaction is completed, the obtained hydrogenated product solution is treated with alcohol. Examples of the alcohol used include methanol, ethanol, isopropyl alcohol, and 2-butanol, and among these, isopropyl alcohol is particularly preferred. In this alcohol treatment step, specifically, the hydrogenated product solution may be poured into alcohol, or alcohol may be added to the solution, sufficiently stirred and mixed, and then left to stand. The hydrogenation product solution before such alcohol treatment has a catalyst dispersed in it and is a dark colored solution as a whole;
When mixed with alcohol in a container as described above and left to stand, the solution separates into two layers, upper and lower in color. In other words, the solvent composition of the upper and lower layers is exactly the same, but the upper layer is a colorless, transparent or slightly cloudy bright solution, while the lower layer is a transparent or opaque solution, depending on the type of catalyst used. The catalyst is dispersed in the solution, resulting in a gray to black solution. The target highly hydrogenated polymer is dissolved in the bright colored solution in the upper layer, while the unhydrogenated polymer and the low hydrogenated polymer are dissolved in the dark colored solution in the lower layer. The reason why the solution separates into two layers in color tone after alcohol treatment is not yet clear, but it is estimated to be roughly as follows. In other words, in a mixed solvent of the above-mentioned solvent and alcohol used in the hydrogenation reaction, unhydrogenated polymers and low hydrogenated polymers have a high affinity with the catalyst, so that they are mixed with the catalyst in the lower part of the solution. The solution settles to form a dark colored lower layer solution. On the other hand, the portion in which only the highly hydrogenated polymer is dissolved has a lower specific gravity than the lower layer, so this becomes the upper layer. Therefore, it is possible to obtain the desired highly hydrogenated polymer in high yield by separating the upper layer, that is, the bright color solution, and distilling off the solvent. can. [Examples] Examples 1 to 5 A diene polymer having hydroxyl groups at both ends as indicated, a catalyst, and a solvent were charged into a stainless steel pressure-resistant container with an internal volume of 1 equipped with a stirrer and a heater, and
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. Next, add 200 c.c. of alcohol as indicated on the inner wall of the container.
and subsequent washing with 100 c.c. of the indicated solvents and these solvents were added to the reaction product. And internal volume 2
The reaction product solution was placed in a separatory funnel, 200 c.c. of the indicated alcohol was further added, and the mixture was shaken vigorously and allowed to stand still. As a result, the reaction product solution was divided into upper and lower layers in color tone. That is, the upper layer was a transparent to slightly cloudy light colored solution, and the lower layer was a black solution in which the catalyst was suspended. The upper layer was separated, and the solvent was distilled off from this solution using a thin film evaporator. The distillation process was performed at 50℃ and 20mmHg.
The test was carried out in two stages: a first stage of 2 hours at 80°C and 2 mmHg. After that, the hydrogenation rate, yield, and OH of the obtained hydrogenated polymer were determined.
The content was measured and the results are shown in the table. The hydrogenation rate was calculated as follows: bromine number of the diene polymer before hydrogenation - bromine number of the diene polymer after hydrogenation/bromine number of the diene polymer before hydrogenation x 100. On the other hand, for the lower layer, the catalyst was separated into a furnace, the solvent was distilled off using a thin film evaporator in the same manner as above, and the hydrogenation rate, yield, and OH content of the obtained product were measured in the same manner. are also listed in the table. Note that the dark colored solution in the lower layer contains a low hydrogenated polymer and an unhydrogenated polymer, and the hydrogenation rate shown is the hydrogenation rate of this mixture. The catalysts used in Examples 1 to 5 above are as follows. Examples 1 to 3: Nickel (45% by weight) supported diatomaceous earth (manufactured by JGC Chemical Co., Ltd.) Example 4: Palladium (0.5% by weight) supported alumina (manufactured by Nippon Engelhard Co., Ltd.) and nickel (45% by weight) supported
Example 5: 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. (wt%) supported diatomaceous earth (manufactured by JGC Chemical Co., Ltd.) mixed at a weight ratio of 2:8

【table】

[Table] Comparative Example Liquid polybutadiene containing hydroxyl groups (number average molecular weight 2800, OH content
0.82meq/g) 200g, cyclohexane 200g and nickel-diatomaceous earth (Ni4.5g) 10g as catalyst
was charged, hydrogen was introduced therein at a pressure of 50 kg/cm ² G, and the temperature was raised over 60 minutes, followed by a hydrogenation reaction at 130° C. for 4 hours. Thereafter, air was blown onto the outer surface of the container to lower the temperature, and the reaction product was extracted from the container. Then, the catalyst was removed from the reaction product solution, and the solvent was distilled off from the solution using a thin film evaporator as described above. The product thus obtained is a mixture of highly hydrogenated polymer, low hydrogenated polymer and unhydrogenated polymer, and this mixture is poured into a mixed solvent of ethanol and n-hexane. An attempt was made to separate the desired highly hydrogenated polymer by taking advantage of the slight difference in solubility, but it was not possible to separate it effectively. [Effects of the Invention] As is clear from the above explanation, according to the method for producing a hydrogenated polymer of the present invention, after the completion of the hydrogenation reaction, the desired highly hydrogenated polymer can be converted to a less hydrogenated or unhydrogenated polymer. Since the coalescence can be almost completely separated, the target product can be obtained in high yield. Furthermore, the operation involves simply treating the reaction product solution with alcohol, and does not require any complicated steps. Therefore, its industrial value is extremely large, for example in the field of producing raw materials for polyurethane.

Claims (1)

[Claims] 1. A hydrogenated polymer characterized by comprising a step of catalytically hydrogenating a diene polymer containing a hydroxyl group in a solvent and treating the obtained hydrogenated product solution with alcohol. Production method. 2. The manufacturing method according to claim 1, wherein the diene polymer has hydroxyl groups at both ends of the molecule. 3. The manufacturing method according to claim 1, wherein the alcohol is isopropyl alcohol.