JPS61221212A - Production linear oligomer of phenol - Google Patents

Abstract

PURPOSE:To produce the titled oligomer of a narrow MW distribution by a relatively simple operation, by reacting a specified cyclic phenol with a phenol in the absence of any catalyst or in the presence of a basic catalyst or a Lewis acid catalyst. CONSTITUTION:A cyclic phenol of the formula (wherein X's are each a methylene or dimethylene ether unit, at least one of them is a dimethylene ether unit, R is H or a 1-12C alkyl, and n is 1-3) is reacted with phenol or an alkylphenol in the absence of any catalyst or in the presence of a basic catalyst such as an alkali metal hydroxide or a Lewis acid such as aluminum chloride. By utilizing the ring opening reaction of the cyclic phenol of the formula, it is possible to produce a narrow-MW distribution linear oligomer of phenols.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing linear phenolic oligomers having a narrow molecular weight distribution.

[Conventional technology]

Generally, phenolic resins are obtained by reacting phenols with formaldehydes under acidic or basic catalysts, and are widely used in industrial applications as thermosetting resins. However, the phenolic resin produced by the above-mentioned general manufacturing method contains low molecular weight components such as unreacted phenolic monomers and di- or tri-nuclear bodies, and also contains high molecular weight components with a molecular weight of several thousand. It is a mixture.

That is, it is a resin mixture with a wide molecular weight distribution.

Also, slight differences in the amount of catalyst during production, fluctuations in reaction temperature,
Due to uncertainties in end points such as emulsification point and gelling time, the proportions of each component having various molecular weights will vary, resulting in variations between manufacturing lofts. However, with recent industrial materials, it has become important that there is no variation between manufacturing lofts and that the properties are stable.

Furthermore, in terms of physical properties, uniformity of physical property values is required for a variety of uses.

There are two methods for producing phenolic linear oligomers with a narrow molecular weight distribution: a method of fractionating conventional phenolic resins with a wide molecular weight distribution by a separation operation, and a so-called sequential synthesis method in which phenol nuclei are reacted one or several at a time.
There is a method of obtaining the desired linear oligomer through several synthetic operations.

[Problem that the invention seeks to solve]

In the former method, phenolic resins having components with various molecular weights are separated based on the difference in molecular weight, and low molecular weight components and high molecular weight components are removed to obtain oligomers with a narrow molecular weight distribution. This is very difficult and no industrially suitable method has been found.

Furthermore, in the latter sequential synthesis method, the synthesis operations are complicated, such as performing the synthesis operations several times and purifying each time.

The present invention provides a method for producing phenolic linear oligomers with a narrow molecular weight distribution using relatively simple operations.

[Means for solving problems]

The present invention is based on the formula (wherein, X is a methylene group -CH2- or a dimethylene ether group -CHt OCHz-, and at least one is a dimethylene ether group.
2 alkyl groups, and n is an integer of 3 to 8. ) is reacted with phenol or alkylphenols without a catalyst or in the presence of a basic catalyst such as an alkali metal hydroxide or a Lewis acid catalyst such as anhydrous aluminum chloride to form a cyclic phenol (I). This invention relates to a method for producing linear phenolic oligomers with a narrow molecular weight distribution using the ring-opening reaction of ).

The cyclic phenol used in the present invention is, for example, J.

Am, Chem, Soc, 103 3782 (81), the synthesis method of Qutsche et al., the so-called one-step synthesis method.

In this cyclic phenol, at least one of the bonding groups between the phenol cores must be a dimethylene ether group -CHtOCHz- in order to be cleaved in a subsequent reaction. For example, the bishomoxa compounds named by Gutsche et al. are applicable to the present invention. Also, p-substituted cyclic phenol is Org.

It can be converted into an unsubstituted cyclic phenol by the method of BBhmer et al. shown in Prep, Proc, int, supra 113 (78).

To cleave the dimethylene ether group of a cyclic phenol, it is possible to do so without a catalyst, but in that case, a long-term high-temperature reaction is required, and in order to make the reaction efficient, lithium hydroxide, sodium hydroxide, potassium hydroxide, etc. A basic catalyst such as, or a Lewis acid catalyst such as anhydrous aluminum chloride, boron trifluoride, or tin chloride is used. The amount added is cyclic phenol 1
It is preferred to use 0.5 to 2.0 moles per mole, and it is necessary to add phenol or alkylphenols as a reaction partner with the cleaved dimethylene ether bond. The amount added is 1.0% per mole of cyclic phenol.
0 to 20 mol is preferred.

Furthermore, regarding the reaction temperature, dimethyl
A high temperature is required to cleave the lene ether group, and the temperature is preferably 100 to 210°C.

The reaction of the present invention can be carried out either in solution or in a molten state. However, when the reaction is carried out in a solution, a solvent having a boiling point of 100° C. or higher, such as toluene or xylene, is used to maintain the above reaction temperature. Further, when the reaction is carried out in a molten state, in order to make the reaction system uniform, it is preferable to equalize or suspend the cyclic phenol and the phenol or phenols in an appropriate solvent before starting the reaction.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

Examples 1 to 4, Comparative Example 1j equipped with a cooling tube, a moisture meter, a thermometer, and a stirring device! 60 g of p-tert-butylphenol and 30 g of 80% rose formaldehyde in a four-bottle flask.
and 500 ml of industrial xylene were added, and 1 liter of 5N aqueous potassium hydroxide solution was added, followed by reaction at reflux temperature for 4 hours. The condensed water produced was collected in a water meter. The precipitated solid content was filtered, the xylene solution was returned to the distillation flask, the xylene was concentrated under reduced pressure, and the mixture was further dried under vacuum to obtain 44 g of a yellowish brown solid. This yellowish brown solid was recrystallized several times using a mixed solvent of methylene chloride and methanol to obtain 10 g of bishomoxa tetracycle.

2g of this cyclic phenol and phenol or p-tar
3 to 4 g of t-butylphenol were once dissolved in acetone, and the solid obtained by removing the acetone was reacted with sodium hydroxide or anhydrous aluminum chloride as a catalyst in an oil bath at 150°C for 30 minutes. ,THF
50s+1 was added to remove THF-insoluble components.

Table 1 shows the formulations, reaction conditions, and product amounts of Examples 1 to 4 and Comparative Examples.

The margins below and the molecular weight distribution of the obtained resin are manufactured by Toyo Soda Co., Ltd.
High performance liquid chromatography HCL-801 type (columns: TSK-GaLOG-2000H, #3, and G-3000H, #1, eluent THF 1
．． 5 ml/min).

The results are shown in FIG.

In the figure, 1 is the peak of bishomoxa tetracycle, 2 is p-t
The peak of ert-butylphenol and 3 are the peaks of phenol.

From FIG. 1, in Examples 1.2 and 3, the peak of the bishomoxa tetracyclic starting material almost disappears, and phenolic linear oligomers with a narrow molecular weight distribution are produced on the polymer side. In the comparative example, since phenol or phenols were not added, the bishomoxa tetracyclic ring was hardly decomposed and did not react.

The reaction products in Examples 1.2.3 and 4 were made into an acetone solution, and unreacted bishomoxa tetracycles were filtered off. Next, water was further added to the acetone solution to reprecipitate the resin component. The molecular weight distribution of the obtained precipitate is similar to that of the oligomer components of Examples 1.2.3 and 4 in Figure 1, and is a narrow phenolic line with a narrow molecular weight distribution in which most of the monomers phenol and PTBP have been removed. It was an oligomer.

In addition, to confirm that it is a phenol linear oligomer,
In addition to being easily soluble in acetone, by infrared spectrophotometry,
Absorption position of phenolic hydroxyl group is normal 3400-35
00 cm-', and it was confirmed that the intramolecular hydrogen bond peculiar to cyclic phenol was broken.

〔Effect of the invention〕

According to the present invention, by synthesizing a cyclic phenol, purifying it, and subsequently performing a ring-opening reaction of the cyclic phenol,
It is possible to easily obtain phenolic linear oligomers with a narrow molecular weight distribution without the need for special fractionation operations from general phenolic resins with a wide molecular weight distribution, and without performing complicated synthesis operations as in the sequential synthesis method. can.

[Brief explanation of drawings]

FIG. 1 is a chart showing the molecular weight distribution of the reaction products obtained in Examples 1.2.3.4 and Comparative Examples. 5 Yo, Tsuji E (Tatsushito Sada) Figure 1

Claims (1)

[Claims] 1. Formula, ▲Mathematical formula, chemical formula, table, etc.▼ (In the formula, X is a methylene group -CH_2- or a dimethylene ether group -CH_2OCH_2-, and at least one is a dimethylene ether group. R is hydrogen or an alkyl group having 1 to 12 carbon atoms, and n is an integer of 3 to 8. A method for producing a linear phenol oligomer, which comprises reacting in the presence of a catalyst.