JP2017095414A - Manufacturing method of alkoxyphenols - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for providing alkoxyphenols at high yield and low cost by suppressing generation of by-products even when using higher aliphatic alcohol having 6 or more carbon atoms as a raw material.SOLUTION: As a result of assiduous investigation on a manufacturing method of alkoxyphenols, dihydric phenol and aliphatic alcohol are dehydration condensation reacted in presence of a solvent and an acid catalyst.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing alkoxyphenols.

  Alkoxyphenols are widely used as raw materials for pharmaceuticals, fragrances, stabilizers (antioxidants, polymerization inhibitors) and the like, and are industrially very useful compounds.

  As a method for producing alkoxyphenols, a method of reacting a phenolic compound and an alkyl halide in the presence of a base, a method of dehydrating condensation of a phenolic compound and an alcohol in the presence of an acid, etc. are widely known.

  The method of reacting a phenolic compound and an alkyl halide in the presence of a base is not suitable for industrialization because a step such as post-treatment is required because an alkyl halide is used as a reaction raw material.

  As a method for dehydrating and condensing a phenolic compound and an alcohol in the presence of an acid, for example, a method of reacting a benzoquinone with an alcohol in the presence of an acidic dehydration catalyst has been proposed (Patent Document 1). However, in this method, since benzoquinones are hardly consumed during the reaction and remain as unreacted substances, a separation and removal step of benzoquinones is required, and a complicated post-treatment step is unavoidable. .

  Further, a method for synthesizing alkoxyphenols by reacting hydroquinones with alcohols in the presence of a heteropolyacid such as phosphomolybdic acid has been proposed (Patent Document 2). However, the heteropolyacid is very expensive and disadvantageous for industrialization, and in this reaction, there is a problem that a dehydration condensation reaction further proceeds and a by-product dialkoxybenzene is produced in a large amount.

  Furthermore, it is generally known that the greater the number of carbon atoms in the aliphatic alcohol, the lower the reactivity and selectivity, making it difficult to synthesize the target alkoxyphenol. Therefore, even when a higher aliphatic alcohol having 6 or more carbon atoms is used as a raw material, there has been a demand for a method for producing alkoxyphenols that is inexpensive and produces less by-products.

Japanese Patent Publication No. 60-41649 Japanese Patent Publication No. 1-32213

  An object of the present invention is to suppress the production of by-products even when a higher aliphatic alcohol having 6 or more carbon atoms is used as a raw material, and to obtain alkoxyphenols at a high yield and at a low cost. It is to provide a manufacturing method.

  As a result of intensive investigations on the production method of alkoxyphenols, the present inventors have conducted dehydration condensation reaction of dihydric phenol and aliphatic alcohol in the presence of a solvent and an acid catalyst, thereby producing dialkoxybenzene as a by-product. It was found that production was suppressed and alkoxyphenols were obtained in high yield, and the present invention was completed.

（式中、Ｒは炭素原子数６〜２０のアルキル基を表す。） That is, the present invention includes the step of reacting the dihydric phenol represented by the formula (1) with the aliphatic alcohol represented by the formula (2) in the presence of a solvent and an acid catalyst. A process for producing the represented alkoxyphenols is provided.

(In the formula, R represents an alkyl group having 6 to 20 carbon atoms.)

（式中、Ｒは炭素原子数６〜２０のアルキル基を表す。） According to the present invention, by-product of dialkoxybenzene represented by the formula (4) is suppressed, and even when a higher aliphatic alcohol having 6 or more carbon atoms is used as a raw material, the target alkoxy Phenols can be obtained at low cost and in high yield.

(In the formula, R represents an alkyl group having 6 to 20 carbon atoms.)

  In the present invention, examples of the dihydric phenol represented by the formula (1) as a starting material include hydroquinone, resorcinol and catechol. Among these, hydroquinone is preferable because it is easily available and has excellent reactivity.

  The aliphatic alcohol represented by the formula (2) used in the present invention may be linear or branched, and 1-hexanol, 1-heptanol, 1-octanol, 2-ethyl- 1-hexanol, 1-nonanol, 1-decanol, 1-undecanol, 1-dodecanol, 1-tridecanol, 1-tetradecanol, 1-pentadecanol, 1-hexadecanol, 1-heptadecanol, 1- Examples include octadecanol, 1-nonadecanol, and 1-icosanol. Among these, 1-octanol and 2-ethyl-1-hexanol are preferable because they are easily available and have excellent reactivity.

  As the aliphatic alcohol used in the present invention, commercially available products may be used, or those produced by methods known to those skilled in the art may be used.

  The aliphatic alcohol used in the present invention is preferably reacted in an amount of 1.0 to 5.0 mol, more preferably 1.1 to 3.0 mol, per 1 mol of dihydric phenol. When the aliphatic alcohol is less than 1.0 mol with respect to 1 mol of the dihydric phenol, the residual amount of the unreacted dihydric phenol tends to increase. When it exceeds 5.0 mol with respect to 1 mol of dihydric phenol, there exists a tendency for the reactivity to fall.

  Examples of the acid catalyst used in the present invention include one or more selected from the group consisting of p-toluenesulfonic acid, methanesulfonic acid, benzenesulfonic acid and sulfuric acid. Among these, p-toluenesulfonic acid is preferable because it is excellent in suppressing the formation of by-products.

  In the present invention, in the reaction of the dihydric phenol and the aliphatic alcohol, the presence of a solvent suppresses the production of dialkoxybenzene as a by-product, and the alkoxyphenol can be obtained in a high yield.

  Examples of the solvent used in the present invention include one or more selected from the group consisting of mesitylene, xylene, light oil and toluene. Among these, mesitylene, xylene and light oil are preferable from the viewpoint of excellent production suppression of by-products and alkoxyphenols, and mesitylene is particularly preferable from the viewpoint of higher productivity.

  The amount of the solvent used in the present invention is not particularly limited because it varies depending on the type of the solvent, but is preferably 0.5 to 3.0 times, more preferably 0.8 to 2.0, relative to the dihydric phenol. It is better to select appropriately between the times. When the amount of the solvent is less than 0.5 times that of the dihydric phenol, the byproduct suppression effect is not sufficiently obtained, and when it exceeds 3.0 times, the reaction rate tends to decrease.

  In the present invention, the reaction temperature between the dihydric phenol and the aliphatic alcohol is appropriately set in the range below the boiling point of the solvent used, preferably 140 ° C. to 200 ° C., more preferably 150 ° C. to 190 ° C., particularly Preferably it is 160 to 180 degreeC. When the reaction temperature is lower than 140 ° C., the reaction tends not to proceed sufficiently. When the reaction temperature is higher than 200 ° C., the amount of by-products such as dialkoxybenzene tends to increase.

  In the present invention, the reaction time between the dihydric phenol and the aliphatic alcohol is not particularly limited because it varies depending on conditions such as the reaction temperature, but is preferably 5 to 20 hours, more preferably 6 to 15 hours, and particularly preferably 7 It is suitably selected between 10 hours.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.

[Production rate]
The molar ratio (%) of the production amount of each component to the charged amount of dihydric phenol was taken as the production rate.
The production amount of each component was determined by quantitative analysis by high performance liquid chromatography (HPLC) under the following conditions.

[High-performance liquid chromatography (HPLC)]
Model: Waters Alliance 2690/2996
Column: L-Column
Wavelength: 229nm
Solvent ratio: H ₂ O (pH 2.3) / CH ₃ CN = 90/10 (7 min) → 5 min → 45/55 (24 min) → 3 min → 5/95 (50 min)
Flow rate: 1.0 mL / min
Column temperature: 40 ° C

Example 1
Hydroquinone 44 g, 1-octanol 62.5 g, p-toluenesulfonic acid 4.4 g and mesitylene 44 g were added to a 300 mL four-necked flask equipped with a stirrer, a temperature sensor and a Dean-Stark apparatus, and the mixture was heated to 170 ° C. under a nitrogen stream. The temperature was raised and the reaction was carried out at the same temperature for 7 hours. The obtained reaction solution was subjected to quantitative analysis of each component by HPLC. The results are shown in Table 1.

Example 2
The reaction was conducted in the same manner as in Example 1 except that 44 g of xylene was added instead of 44 g of mesitylene and the reaction temperature was 160 ° C. The results are shown in Table 1.

Example 3
The reaction was conducted in the same manner as in Example 1 except that 44 g of light oil was added instead of 44 g of mesitylene. The results are shown in Table 1.

Example 4
The reaction was performed in the same manner as in Example 1 except that the amount of 1-octanol was changed from 62.5 g to 104.2 g. The results are shown in Table 1.

Comparative Example 1
The reaction was performed in the same manner as in Example 1 except that 44 g of mesitylene was not added. The results are shown in Table 1.

Example 5
Hydroquinone 44 g, 1-hexadecanol 116.4 g, p-toluenesulfonic acid 4.4 g, and mesitylene 44 g were added to a 300 mL four-necked flask equipped with a stirrer, a temperature sensor, and a Dean-Stark apparatus. The temperature was raised to 0 ° C., and the reaction was carried out at the same temperature for 7 hours. The obtained reaction solution was subjected to quantitative analysis of each component by HPLC. The results are shown in Table 2.

Comparative Example 2
The reaction was conducted in the same manner as in Example 5 except that 44 g of mesitylene was not added. The results are shown in Table 2.

Example 6
Under a nitrogen stream, 44 g of hydroquinone, 62.5 g of 2-ethyl-1-hexanol, 4.4 g of p-toluenesulfonic acid and 44 g of mesitylene were added to a 300 mL four-necked flask equipped with a stirrer, a temperature sensor and a Dean-Stark apparatus. The temperature was raised to 170 ° C. and reacted at the same temperature for 7 hours. The obtained reaction solution was subjected to quantitative analysis of each component by HPLC. The results are shown in Table 3.

Comparative Example 3
The reaction was performed in the same manner as in Example 6 except that 44 g of mesitylene was not added. The results are shown in Table 3.

Comparative Example 4
Hydroquinone 55 g, potassium carbonate 69 g and DMF 275 g were added to a 1 L four-necked flask equipped with a stirrer and a temperature sensor, and the temperature was raised to 80 ° C. under a nitrogen stream. Subsequently, 96.6 g of 1-bromooctane was added dropwise at the same temperature over 2 hours and reacted at the same temperature for 7 hours. The obtained reaction solution was subjected to quantitative analysis of each component by HPLC. The results are shown in Table 4.

Comparative Example 5
The reaction was performed in the same manner as in Comparative Example 1 except that the reaction temperature was 60 ° C. The results are shown in Table 4.

Comparative Example 6
Hydroquinone 55 g, potassium carbonate 69 g, potassium iodide 2.5 g, 1-bromo-2-ethylhexane 96.6 g and DMSO 275 g were added to a 1 L four-necked flask equipped with a stirrer and a temperature sensor. The reaction was carried out at 20 ° C. for 12 hours. The obtained reaction solution was subjected to quantitative analysis of each component by HPLC. The results are shown in Table 4.

As shown in Tables 1 to 3, according to the present invention, by-products such as dialkoxybenzene (1,4-dioctyloxybenzene, 1,4-dihexadecyloxybenzene, 1,4-di (2-ethylhexyl) are used. Oxy) benzene) formation is suppressed, and the target alkoxyphenols (4-octyloxyphenol, 4-hexadecyloxyphenol, 4-di (2-ethylhexyloxy) phenol) can be obtained in high yield. it can.
Moreover, as shown in Table 4, the method of reacting a dihydric phenol and an alkyl halide in the presence of a base does not sufficiently suppress the formation of by-products, and produces alkoxyphenols in a high yield. I can't.

Claims (6)

Alkoxyphenol represented by formula (3), comprising a step of reacting a dihydric phenol represented by formula (1) with an aliphatic alcohol represented by formula (2) in the presence of a solvent and an acid catalyst. Manufacturing method.

(In the formula, R represents an alkyl group having 6 to 20 carbon atoms.)   The alkoxyphenol represented by formula (3) is selected from the group consisting of 4-octyloxyphenol, 3-octyloxyphenol, 4- (2-ethylhexyloxy) phenol and 4- (2-ethylhexyloxy) phenol. The manufacturing method according to claim 1.   The manufacturing method of Claim 1 or 2 with which 1.0-5.0 mol of aliphatic alcohol is made to react with respect to 1 mol of dihydric phenols.   The manufacturing method in any one of Claims 1-3 whose solvent is 1 or more types selected from the group which consists of mesitylene, xylene, light oil, and toluene.   The manufacturing method in any one of Claims 1-4 whose acid catalyst is 1 or more types selected from the group which consists of p-toluenesulfonic acid, methanesulfonic acid, benzenesulfonic acid, and a sulfuric acid.   The production method according to any one of claims 1 to 5, wherein the dihydric phenol and the aliphatic alcohol are reacted at a temperature of 140 to 200 ° C.