JPH10330305A - Etherification of phenols - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for etherification of a phenol which gives the high-purity product in high yield through a safe and simple procedure by reacting an alkali metal salt of the phenol with an alkylene glycol or the like in the presence of carbon dioxide. SOLUTION: This method reacts (A) an alkali metal salt of a phenol with (B) an alkylene glycol (alkyl-substituted) in the presence of carbon dioxide at 180 to 250 deg.C, preferably 200 to 220 deg.C, for 2 to 10 h, preferably 3 to 6 h. The initial component A/component B molar ratio is preferably 1/2 to 1/50, more preferably 1/5 to 1/30. Carbon dioxide gas pressure is preferably 1 to 30 kg/cm<2> , more preferably 10 to 20 kg/cm<2> . The preferable compounds for the component A include sodium or potassium salt of phenol, catechol, resorcin, biphenol and bisphenol F. The preferable compounds for the component B are ethylene glycol and propylene glycol.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for etherifying phenols, which is an organic synthesis reaction, that is, a novel method for producing hydroxyalkylene ethers of phenols. The hydroxyalkylene ether of phenols produced according to the present invention is useful as a raw material for synthesizing medicines, agricultural chemicals, dyes and the like, or as a polymerization component such as polyester resin and polyurethane resin.

[0002]

2. Description of the Related Art Hitherto, processes for producing hydroxyalkylene ethers of phenols have been extensively studied because of their high industrial utility, and many processes have been disclosed. A basic method for producing hydroxyalkylene ethers of phenols is a method of adding ethylene oxide to hydroxyl groups of phenols (JP-A-8-20).
8550), but as another method, a method of adding ethylene carbonate (JP-A-8-295646)
A method of reacting a phenol with a hydroxyethyl halide (JP-A-48-4434), a method of reacting a phenol with ethylene glycol using a bismuth diacetate catalyst (Tetrahedoron Lett. Vol. 22 No. 50p
5063-6, 1981). However, the above-mentioned conventional method has various disadvantages, and in the method of adding ethylene oxide, it is difficult to handle ethylene oxide, which is also regulated by dangerous substances, and special equipment is required. 1 addition of ethylene oxide
It is difficult to stop at the stage, and a chain reaction occurs. On the other hand, in a method using a catalyst, it is difficult to remove the remaining catalyst, and this tends to cause a problem of coloring or deterioration of the polymer due to the remaining catalyst. Other conventional methods also have problems such as a difficulty in stopping the hydroxyalkylene etherification reaction in one step, a difficulty in post-treatment, and a low purity and yield of the reaction product.

[0003]

In the above-mentioned conventional method, the hydroxyalkylene etherification reaction is difficult to stop in one step, and causes a chain reaction, which is useful as a raw material for pharmaceuticals and agricultural chemicals or a polymerization component of polymers. Since it is difficult to form a step adduct, there is a need for a method for efficiently and selectively adding an alkylene oxide in one step. In addition, a simple and safe method, a hydroxyalkylene ether compound having high purity and high yield is required. Has also been a challenge.

[0004]

Means for Solving the Problems In view of the problems of the prior art, the present inventors have conducted various studies on the hydroxyalkylene etherification reaction of phenols and found that carbon dioxide (carbon dioxide)
The above problem was solved by performing this reaction in the presence of. The basic structure of the present invention is to produce a hydroxyalkylene ether of a phenol by a hydroxyalkylene etherification reaction, and is characterized by a synthesis reaction of reacting an alkali metal salt of a phenol with an alkylene glycol in the presence of carbon dioxide gas. It is assumed that. Moreover, the method of the present invention is characterized in that the reaction operation is safer and simpler than in the conventional method, and the purity and yield of the product are extremely high.

Specifically, the method of the present invention is a method for etherifying phenols by reacting an alkali metal salt of phenols with an alkylene glycol or an alkyl-substituted alkylene glycol in the presence of carbon dioxide. By reacting ethylene glycol or an alkyl-substituted ethylene glycol in the presence of carbon dioxide, a method for etherifying phenols, an alkali metal salt of phenols,
A method for etherifying phenols by reacting propylene glycol or an alkyl-substituted propylene glycol in the presence of carbon dioxide, wherein the phenols are phenol, catechol, resorcin, hydroquinone, pyrogallol, phloroglucin, naphthol, biphenol, bisphenol F And a method of etherifying phenols, which is one selected from their derivatives.
A method for etherifying phenols, wherein the alkali metal salt is a sodium salt or a potassium salt.

[0006]

The reaction formula of the etherification reaction of biphenol with ethylene glycol is shown below as a typical example of the synthesis reaction of the present invention.

Embedded image

When a carbon dioxide gas is allowed to act on an alkali metal salt of a phenol in an alcohol solvent, the reaction to form a metal oxycarboxylate is a synthesis reaction known as the Kolbe-Schmitt reaction. When an alkali metal salt of a phenol is reacted with ethylene glycol or propylene glycol in the presence of carbon dioxide gas, the hydroxyalkylene etherification reaction of the phenol is surprisingly efficiently performed, and the etherification reaction is surprising. It selectively stops in one step and little chain etherification occurs. Also, in the case of bicyclic phenols, etherification is performed at both hydroxyl groups, etherification is selectively stopped in one step, and the same applies to tricyclic phenols.

As the phenol of the alkali metal salt of phenol used in the present invention, various phenols can be used, and as a monocyclic compound, monovalent phenol or crezo-
Dicyclic catechol, resorcin, hydroquinone, pyrogallol, etc. as polycyclic compounds such as monovalent naphthol, cumylphenol, cyclohexylphenol, Examples include trivalent biphenol, bisphenol F, 4,4'-phenylmethylenebisphenol, and trivalent 4,4 ', 4 "-methylidenetrisphenol. The alkali metal salt is preferably a sodium salt or a potassium salt, and the alkyl group of the alkylene glycol or the alkyl-substituted alkylene glycol has an alkyl group of 2 carbon atoms.
Preferred are aliphatics having up to 4 aliphatic acids, more preferably ethylene glycol or propylene glycol having 2 or 3 carbon atoms. This reaction is unlikely to occur with 1,5-pentanediol or glycols having a longer alkylene chain. Further, as the alkyl-substituted product, a substituted product in which an alkyl group is branched and substituted in an ethylene chain or a propylene chain can also be used.

The reaction operation in the method of the present invention is as follows. A container such as a flask or an autoclave is charged with an alkali metal salt of phenol and an alkylene glycol, and is replaced with carbon dioxide. Let react. After completion of the reaction, the crude crystals may be filtered off and purified by adding alcohol. The molar ratio of the alkali metal salt of the phenol to the alkylene glycol used is a large amount of the alkylene glycol, but the molar ratio of the alkali metal salt of the phenol to the alkylene glycol is 1/2 to
1/50, preferably 1/3 to 1/40, more preferably 1/5 to 1 /
It is in the range of 30. The reaction is carried out at a temperature of 180 to 250 ° C., preferably 200 to 220 ° C., a carbon dioxide pressure of 1 to 30, preferably 10 to ²⁰ kg / cm ² , and a reaction time of 2 to 10 hours, preferably 3 to 6 hours. Time.

[0010]

The present invention will be described in more detail with reference to the following Examples, which by no means limit the present invention.

Example 1 [Etherification of Biphenol with Ethylene Glycol] a. Preparation of Na salt of biphenol; 18.6 g of biphenol and 60.0 g of methanol were charged into a 500 ml flask, and stirred under nitrogen atmosphere with 30% sodium methylate 36.0 g. g
Was added dropwise. The methanol in the flask was distilled off to obtain 23.0 g of a biphenol Na salt. b. Etherification of biphenol Na salt; charge the obtained biphenol Na salt 23 gr and ethylene glycol 100 gr into a 200 ml autoclave, replace with carbon dioxide gas, raise the temperature to 220 ° C, and increase the carbon dioxide gas pressure to 15 kg / cm ^2. The reaction was performed under pressure for 3 hours. To confirm the compounds, methanol was added to the reaction-terminated liquid and analyzed by HPLC (high performance liquid chromatography). The biphenol component composition was found to be dietherified biphenol 7
It was confirmed that the content was 8.4%, monoetherified biphenol 13.6%, unreacted biphenol 0.8%, and others 7.8%. Next, 110 gr of methanol was added to the reaction completed solution,
The insoluble material was filtered off, and the insoluble material thus filtered was washed with 100 g of water.
After adjusting the pH to 7 with a hydrochloric acid aqueous solution, the mixture was filtered and dried to obtain 19 gr of a white powder. The etherification purity of this white powder is
HPLC analysis indicated 94.9%. For further purification, THF was added to the white powder, refluxed, cooled, and filtered to obtain a white powder having a purity of 98% by HPLC analysis. The obtained white powder DI-
The molecular weight by MS (direct insert mass spectrum) was 274, and the proton NMR spectrum by H-NMR was as shown in Table 1.

[0011]

[Table 1]

As a result of the above H-NMR analysis and DI-MS, it was confirmed that the white powder was 4,4'-di (2-cyclodoxyethoxy) biphenyl.

[0013]

[Example 2] [Etherification of biphenol with propylene glycol] a. Preparation of biphenol Na salt; 18.6 g of biphenol and 60.0 g of methanol were charged into a 500 ml flask, and stirred under nitrogen atmosphere with 30% sodium methylate 36.0 g. g
Was added dropwise. The methanol in the flask was distilled off to obtain 23.0 g of a biphenol Na salt. b. Etherification of biphenol Na salt; 23 g of biphenol Na salt and 100 g of propylene glycol in a 200 ml autoclave
After r was charged and replaced with carbon dioxide, the temperature was raised to 220 ° C., the pressure was increased to 15 kg / cm ² , and the reaction was performed for 3 hours. To confirm the compound, methanol was added to the reaction-terminated liquid and analyzed by HPLC (high performance liquid chromatography). The biphenol component composition was 38.8% of dietherified biphenol.
%, Monoetherified biphenol 42.6%, unreacted biphenol 13.1%, and other 5.5%. Next, 67 gr of methanol was added to the reaction-terminated liquid, and unnecessary substances were filtered off.The insoluble matter filtered off was washed with 100 gr of water.
The pH was adjusted to 7 with an aqueous hydrochloric acid solution, followed by filtration and drying to obtain 8 gr of a white powder. The purity of the etherified product of this white powder was 76.6% by HPLC analysis. Then, in order to purify the white powder, THF was added to the white powder, refluxed, cooled, separated by filtration, and a white powder having a purity of 98% was obtained by HPLC analysis. The melting point of the white powder by DSC was 191 ° C., the molecular weight by DI-MS was 302, and the result of NMR analysis was as shown in Table 2. As a result of the analysis, it was confirmed that the finally obtained white powder was 4,4′-di (2-hydroxypropoxy) biphenyl.

[0014]

[Table 2]

[0015]

As described above, the present invention provides a one-step hydroxyalkylene etherification reaction of phenols by using an alkylene glycol having 2 to 4 carbon atoms, such as ethylene glycol or propylene glycol, as an etherifying agent. And a one-step adduct useful as a raw material for medicines, agricultural chemicals, dyes, etc. or a polymerization component of polyester resin or polyurethane resin can be efficiently produced. Further, the method of the present invention exhibits a remarkable effect that a highly pure hydroxyalkylene ether compound can be synthesized by a simple and safe method.

Claims (2)

[Claims] 1. A method for etherifying phenols, comprising reacting an alkali metal salt of phenols with an alkylene glycol and / or an alkyl-substituted product thereof in the presence of carbon dioxide gas. 2. The method for etherifying phenols according to claim 1, wherein the alkylene glycol is ethylene glycol or propylene glycol.