JPS62151404A - Production of hydrogenated polymer - Google Patents

Abstract

PURPOSE:To separate a highly hydrogenated polymer readily and to produce the aimed substance in high yield, by hydrogenating a hydroxyl group-containing diene polymer and treating a solution of the prepared reaction product with an alcohol. CONSTITUTION:A diene polymer [e.g., butadiene polymer, chloroprene polymer, etc., shown by the formula (R is H, Cl or CH3; n is 5-300)] containing hydroxyl groups preferably at both molecular ends is catalytically hydrogenated in a solvent such as pentane, cyclohexane, etc., usually by the use of a catalyst of Ni, Pd, etc., supported on a carrier such as silica, alumina, etc., preferably at 100-200 deg.C at 30-100kg/cm<2>G for 5-10hr and a solution of the prepared hydrogenation product is treated with an alcohol such as isopropyl alcohol, etc. EFFECT:When a solution of prepared hydrogenation product is blended with an alcohol, the solution divided into two layers of the bright solution of the aimed highly hydrogenated polymer and a dark solution containing a nuhydrogenated polymer, a low hydrogenated polymer and a catalyst and separation is readily carried out.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing a hydrogenated polymer, and more particularly, to a method for producing a hydrogenated product of a diene polymer having a hydroxyl group. , relates to a method for efficiently fractionating the obtained hydrogenated polymer.

[Prior Art] Diene polymers having a hydroxyl group at the end of the molecule, such as butadiene, isoprene or chlorobrene polymers, are heavily used as raw materials for polyurethane. These polymers are used to improve weather resistance and heat resistance.
For example, it is common to hydrogenate in the presence of a catalyst.

When producing such hydrogenated polymers, a catalyst consisting of nickel, palladium, ruthenium, or rhodium supported on a carrier such as silica, alumina, diatomaceous material, or carbon is usually used, and aliphatic hydrocarbon, The polymer is hydrogenated in the presence of the catalyst in a solvent such as an alicyclic hydrocarbon, the catalyst is separated from the resulting hydrogenated product solution, and the solvent is distilled off from the filtrate to obtain the desired product. A method of obtaining hydrogenated polymers has been adopted.

[Problems to be Solved by the Invention] However, in the above method, in addition to the target hydrogenated polymer, that is, the highly hydrogenated polymer, there are , 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 such conventional problems and provides a method for producing a hydrogenated polymer, which includes a step of hydrogenating a diene polymer having a hydroxyl group and then efficiently separating a highly hydrogenated polymer by a simple means. The purpose is to provide.

[Means for Solving the Problems] In the course of intensive research to achieve the following objectives, the present inventors mixed alcohol and the hydrogenated product solution obtained after the completion of the hydrogenation reaction. , when left to stand still, in a mixed solvent system of the solvent and alcohol used for 1 reaction, 2 different tones of 1 color appear.
The layer solutions, i.e., the light color solution of the highly hydrogenated polymer as 1-1, and the HHfS color solution in which the unhydrogenated polymer, the low hydrogenation polymer, and the catalyst are present, are determined by the difference in specific gravity between the two solutions. As a result, they discovered the fact that it can be divided into two lower phases, and completed 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: % formula %) (wherein R represents a hydrogen atom, a chlorine atom or a methyl group, and n represents an integer from 5 to 300. ),
Namely, butadiene, chloroprene or isoprene polymers may be mentioned.

In addition, the solvent used at this time is not particularly limited, and examples include aliphatic hydrocarbons such as pentane, hexane, heptane, and octane; cyclopentane,
Suitable examples include alicyclic hydrocarbons such as cyclohexane and methylcyclohexane.

Furthermore, the catalyst used in the reaction is, for example, one of Ni, Pd and Rh, or two containing Ni supported on a carrier such as silica, alumina, silica alumina, diatom, carbon, etc. Things are useful.

Next, the manufacturing process of the hydrogenated polymer of the present invention will be explained step by step.

First, for example, the above-mentioned diene polymer, catalyst, and solvent are charged into 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'C1, preferably 100-200°C,
The pressure is 10-200 kg/crn'G, preferably 3
0-100kg/cm''G, reaction time 0.1-100
Each time is preferably set to 0.5 to 10 hours.

After the reaction is completed, the obtained hydrogenated product solution is treated with alcohol. The alcohol to be used is methanol, ethanol, isopropyl alcohol, etc. Examples include -butanol, among which 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 hydrogenated product solution before alcohol treatment has a catalyst dispersed in it and is a dark colored solution as a whole, but when it is mixed with alcohol in a container and left to stand as described above, the solution has two layers (top and bottom) in color tone. Separate into In other words, the solvent composition of the two lower layers is exactly the same, but the upper layer becomes a colorless and transparent or slightly cloudy bright solution, while the lower layer becomes a transparent or opaque solution, depending on the type of catalyst used. The catalyst is dispersed, 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.

Thus, after alcohol treatment, the solution becomes 2 in color.
Although the cause of the separation into layers is not yet clear, it is estimated 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, by separating the upper layer, that is, the bright color solution, and distilling off the solvent, the desired highly hydrogenated polymer can be obtained in high yield.

[Example] 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 liter, equipped with a stirrer and a heater, and then hydrogen gas was added. After the temperature was raised over 60 minutes, hydrogenation was carried out under the indicated conditions.

Afterwards, air is blown onto the outer surface of one container to lower the temperature.
The reaction product was extracted.

The inner wall of the container was then washed with 200 cc of the indicated alcohol and subsequently with 100 cc of the indicated solvent, and these solvents were added to the reaction product. Then, pour the reaction product solution into a separating funnel with an internal volume of 2 liters, and add 200 c of alcohol as indicated.
c was further added, and the mixture was shaken vigorously and allowed to stand still. As a result, the reaction product saliva 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. this house,
The upper layer was separated, and the solvent was distilled off from this solution using a thin film evaporator. The distillation step was carried out in two stages: a first stage at 50°C and 20 mmHg for 1 hour, and a second stage at 80°C and 2 mmHg for 2 hours. Thereafter, the hydrogenation rate, yield, and OH content of the obtained hydrogenated polymer were measured, and the results are shown in the table. Note that the hydrogenation rate was calculated as follows.

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 resulting product was measured for hydrogenation rate, yield, and OH content. The results 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 1-3: Nickel (45% by weight) supported diatom ±
(manufactured by JGC Chemical ■) Example 4: Palladium (0.5% by weight) supported alumina (
(manufactured by Nippon Engelhard) and nickel (45% by weight) supported diatomaceous material (manufactured by JGC Chemical ■) at a weight ratio of 228. Example 5: Rhodium (5% by weight) supported carbon (Nippon Engelhardt) Comparative Example A mixture of nickel (45% by weight) supported diatomaceous earth (manufactured by JGC Chemical Co., Ltd.) at a weight ratio of 2:8.Comparative Example: A stainless steel pressure-resistant container with an internal volume of 1 liter and equipped with a stirrer and a heater was charged with hydroxyl groups. Liquid polybutadiene containing (number average molecular weight 2800, OH content 0, 82 meq/g
) 200 g, cyclohexane 200 g, and nickel-diatom ± (Ni 4.5 g) log as a catalyst were charged, hydrogen was introduced at a pressure of 50 kg/cm'G, the temperature was raised in 60 minutes, and then hydrogenated at 130°C for 4 hours. The reaction was carried out. 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 separated from the reaction product solution, and the solvent was distilled off from the filtrate using the thin film generator 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. Attempts were made to separate the desired highly hydrogenated polymer by taking advantage of the slight difference in solubility, but this did not lead to effective separation.

[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 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. manufacturing method. 2. The production 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.