JPS6056164B2 - Polybutadiene epoxidation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for epoxidizing polybutadiene.

Utilizing its properties, epoxidized polybutadiene (hereinafter referred to as epoxy polybutadiene) has been widely developed as a plasticizer for polymer compounds, a stabilizer, an adhesive, a modifier for synthetic resins, a paint, etc. In recent years, there has been a rapid shift from conventional anionic electrocoating to cationic electrocoating for rust prevention of automobiles, and its use as a raw material epoxy resin for cationic electrocoating for automobiles has been attracting attention.

A conventionally known method for epoxidizing polybutadiene is to generate an acidic peracid such as performic acid, peracetic acid, perpropionic acid, perbenzoic acid, perlauric acid, etc.
Preform epoxidized with these organic peracids
An organic peracid produced by the edPeracid method or by directly adding hydrogen peroxide and an organic acid such as formic acid, acetic acid, or propionic acid to an epoxidation reaction system in the presence of an acidic catalyst such as sulfuric acid or a strongly acidic ion exchange resin. There is an in-situ method, etc., in which epoxidation is immediately performed. These conventional methods have several drawbacks as described below, and are not necessarily satisfactory methods.

(a) Since an organic peracid with explosive properties is used in the reaction, utmost care must be taken to ensure safety.

(Note) When extracting the epoxy polybutadiene, which is a reaction product, the organic acids and organic peracids contained in the oil phase must be removed by washing with a large amount of water. This is extremely difficult because the viscosity of the oil phase has increased due to oxidation. (c) Measures must be taken to deal with organic acids (acetic acid, formic acid, etc.) produced as by-products after the epoxidation reaction.

(d) Due to the strong acid catalyst, even if epoxide is generated, the oxirane ring is easily opened, and side reaction products such as glycols and mole esters containing hydroxyl groups and ester groups are generated in the reaction product. generated. (e) It is difficult to recycle unreacted raw materials in the reaction system.

The inventor of the present invention has conducted repeated research to improve the drawbacks of the conventional methods as described above, and as a result, has invented a new method for epoxidizing polybutadiene.

That is, the present invention combines a solution of polybutadiene in a water-insoluble organic solvent and hydrogen peroxide with (4) sulfur, nitrogen,
A group consisting of an oxyacid of an element selected from the group consisting of phosphorus, boron, and a halogen, and (B) a compound having a cyclic ether, a polyhydric alcohol, and a polyoxyalkylene group (substances included in this group are hereinafter referred to as compound B). ) is a polybutadiene epoxidation method characterized by contacting and reacting in the coexistence of a compound selected from the following.

The water-insoluble organic solvent used in the present invention is not particularly limited as long as it is inert during the epoxidation reaction, and can be used in a wide range of ways.

For example, aromatic hydrocarbons such as benzene, toluene, and xylene, aliphatic hydrocarbons such as n-hexane, n-heptane, cyclohexane, and halogenated charcoal. Hydrogen such as chloroform and trichloroethylene are preferably used. In addition, the water-insoluble organic solvent is a factor that affects the epoxidation reaction rate of polybutadiene, including the type of oxic acid, the type and amount of compound B added, and the reaction temperature! It is preferable to select them together. These solvents serve to reduce the viscosity of the epoxy polybutadiene produced. The hydrogen peroxide used in the present invention can be a commercially available product with a concentration of 10 to (1)%, or it can be in a more concentrated state, and the concentration is not particularly limited. However, in any case, the hydrogen peroxide concentration at the start of the epoxidation reaction is 30~
A range of 60 Wt% is appropriate.

The molar ratio of hydrogen peroxide and epoxy polybutadiene (value determined from the iodine value) can be varied over a wide range and is not particularly limited, but in general, the molar ratio of hydrogen peroxide to polybutadiene is 1:1 to 1:5. A range of is desirable.

The oxyacid of an element selected from the group consisting of sulfur, nitrogen, phosphorus, boron, and halogen used in the present invention typically includes sulfuric acid, nitric acid, phosphoric acid, boric acid, and chloric acid. ) Those with high or low oxidation states, or those in an anhydrous state can also be used.

Examples include sulfurous acid, pyrosulfuric acid, sulfuric anhydride, hyponitrous acid, nitrous acid, hypophosphoric acid, hypophosphorous acid, metaphosphoric acid, pyrophosphoric acid, metaboric acid, tetraboric acid, boric anhydride, perchloric acid, and the like. Furthermore, derivatives of the above oxyacids such as benzenesulfonic acid, p-toluenesulfonic acid, and acid salts of the above oxyacids are also included in the oxyacids that can be used in the present invention. The required amount of oxyacid is determined depending on the amount of polybutadiene, hydrogen peroxide concentration, and type of compound B, since the epoxidation reaction rate is greatly affected by these conditions. can effectively epoxidize polybutadiene. Among the compounds B used in the present invention, examples of cyclic ethers include 1,4-dioxane, trioxane, furan, furfural, 2-
Methylfuran, tetrahydrofuran, tetrahydropyran, dicyclohexyl-18-crown-6, dicyclohexyl-24-crown-8, dicyclohexyl-1
4-crown-4, cyclohexyl-15-crown-5, cyclohexyl-18-crown-6, 18-crown-6, 21-crown-7, 24-crown-8,
Examples include Dipenzo 18-Crown-6, Dipenzo 21-Crown-6, and Dipenzo 24-Crown-8.

Examples of polyhydric alcohols include ethylene glycol,
Diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, trimethylene glycol, butanediol, 1,5-pentanediol, hexylene glycol, heptanediol,
Neopentyl glycol, glycerin, 1,2,6-hexanetriol, pentaerythritol, mannitol, sorbitol, and the like can be used.

Examples of compounds having a polyoxyalkylene group include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyethylene glycol monolaurate, polyethylene glycol monostearate, polyethylene glycol distearate, polyethylene glycol monooleate, and polyoxyethylene sorbitan. Monolaurate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene octylphenol ether, Polyoxyethylene nonylphenol ether and the like can be used.

The amount of compound B added can be varied over a wide range depending on the type and amount of oxyacid used together and the reaction temperature, and is not particularly limited, but addition of a small amount is effective. The epoxidation reaction rate according to the present invention depends on the type of oxyacid, the type and amount of compound B added, the concentration of polybutadiene and hydrogen peroxide, the molar ratio of both, etc., but the reaction temperature is 40 to 70%. Effective epoxidation can be performed under relatively mild conditions of ℃.

According to the present invention described above, all the drawbacks of conventional epoxidation methods using organic peracids can be overcome.

That is, (a) since an explosive organic peracid is not used in the reaction, there is no danger during the reaction caused by the organic peracid, and it is extremely safe.

(b) Since organic peracids are not carried into the reaction product, there is no need to remove them.

(c) Since acetic acid, formic acid, etc. are not used in the reaction, there is no need to consider treatment measures for organic acids produced as by-products after the epoxidation reaction. (d) Since there is no opening of the oxirane ring and there are no side reaction products containing hydroxyl groups and ester groups in the reaction product, high purity epoxy polybutadiene can be obtained.

(e) It is easy to recycle unreacted raw materials in the reaction product. The above (e) recycling of unreacted raw materials will be specifically explained.

After a solution of polybutadiene dissolved in a water-insoluble organic solvent is brought into contact with hydrogen peroxide in the presence of an oxyacid and compound B to cause a reaction, an oil phase and an aqueous phase are separated, and the aqueous phase is concentrated or concentrated. After a portion is discarded, the remaining amount of hydrogen peroxide, oxyacid, and compound B are replenished and used again for the reaction.
Meanwhile, the oil phase is distilled to obtain epoxy polybutadiene!
Thereafter, the polybutadiene can be dissolved in the recovered organic solvent and used again in the reaction. As described above, according to the present invention, unreacted raw materials can be easily recycled, manufacturing costs can be significantly reduced, and the present invention can be carried out economically. Furthermore, in the present invention, water generated during the reaction and water introduced from the hydrogen peroxide used can be removed by evaporation, azeotropic distillation, or the like.

The present invention will be explained in detail below using examples.

The iodine value (Wijs method) and oxirane oxygen content (hydrogen bromide glacial acetic acid method) shown in this specification were determined in accordance with the "Standard Oil and Fat Analysis Test Method" edited by the Japan Oil Chemists' Association. Example 1 Molecular weight 1000, iodine value 370, microstructure related to vinyl bonds, trans-1,4 bonds 16%, cis-1,4
Polybutadiene 6.86y (determined from iodine value, 0.1 mol based on the double bonds of polybutadiene) having a bond content of 17% was weighed into a 100 ml Erlenmeyer flask equipped with a condenser, and dissolved in 60 ml of toluene.

) Add boric acid (H3BO3) to this solution by 0.154 da (2.
After adding 0.04ml of polyethylene glycol (molecular weight 400),
Add 2.84V (0.05 mol) of 0% hydrogen peroxide,
The mixture was reacted at 65° C. for 5 hours while stirring using a magnetic stirrer. After the reaction, the reaction mixture was cooled to room temperature and separated into an oil phase and an aqueous phase, and the oil phase was thoroughly washed with water to remove boric acid and polyethylene glycol contained in the oil phase.

Thereafter, the oil phase was dehydrated and dried over anhydrous sodium sulfate O, filtered, and further distilled under reduced pressure using an evaporator to remove toluene to obtain viscous epoxy polybutadiene. The oxirane oxygen content of this epoxy polybutadiene is 2.1
5%, and the iodine value was 325. Examples 2 to 3 Epoxidation was carried out in the same manner as in Example 1, changing the amount of boric acid added and the reaction time.

The experimental conditions and experimental results are shown in Table-1. Examples 4 to 8 Epoxidation was carried out in the same manner as in Example 1, except that the type of compound B was changed.

The experimental conditions and experimental results are shown in Table-1. Examples 9-1
5 Epoxidation was carried out in the same manner as in Example 1, except that the type of oxyacid was changed.

The experimental conditions and experimental results are shown in Table-1. Example 16 Polybutadiene 6.5f with a molecular weight of 1000, an iodine value of 390, and a microstructure of 90% vinyl bonds and 10% trans-1,4 bonds (calculated from the iodine value, 0.1 mol based on the double bond of polybutadiene) was weighed into a 100 ml Erlenmeyer flask and dissolved in 60 ml of xylene.

After adding 0.35' boric anhydride (B2O3) (0-3 moles of 5.0 moles) and 0.1 ml of glycerin to this solution, it was added to the solution. Add 2.84y of 60% hydrogen peroxide using the same procedure as in Example 1.
(0.05 mol) and the reaction was carried out at 90°C for 7 hours.
The oxirane oxygen of the obtained epoxy polybutadiene is 5
．． It was 1%. Example 17 Molecular weight 1600, iodine value 450, microstructure: 1% vinyl bond, 25% trans-1,4 bond, cis-1,4 bond
Polybutadiene 5.65f with 74% bond (determined from iodine value, 0.1 mol based on double bond of polybutadiene)
Weigh it into a 100ml Erlenmeyer flask, and add 00ml of n
-Dissolved in hexane.

Add 3.35y of 60% perchloric acid (HClO4) to this solution.
(20 x 10-2 mol) and 0.05 ml of polyethylene glycol lauryl ether, then 13.6y (0.1 mol) of 35% hydrogen peroxide was added in the same manner as in Example 1 and reacted at room temperature for 1 hour. I let it happen. The oxirane oxygen content of the obtained epoxy polybutadiene was 3.12%. Comparative Examples 1 to 4 Only oxyacid was added without adding compound B, and Example 1
Epoxidation was carried out in the same manner.

Claims (1)

[Claims] 1. A solution of polybutadiene dissolved in a water-insoluble organic solvent and hydrogen peroxide are mixed into (A) an oxyacid of an element selected from the group consisting of sulfur, nitrogen, phosphorus, boron, and halogen; ) A method for epoxidizing polybutadiene, which comprises contacting and reacting in the presence of a compound selected from the group consisting of a cyclic ether, a polyhydric alcohol, and a compound having a polyoxyalkylene group. 2. The epoxidation method according to claim 1, wherein the oxyacid is sulfuric acid. 3. The epoxidation method according to claim 1, wherein the oxyacid is nitric acid. 4. The epoxidation method according to claim 1, wherein the oxyacid is phosphoric acid. 5. The epoxidation method according to claim 1, wherein the oxyacid is boric acid. 6. The epoxidation method according to claim 1, wherein the oxyacid is p-toluenesulfonic acid. 7. The epoxidation method according to claim 1, wherein the oxyacid is benzenesulfonic acid.