JP3284321B2 - Method for producing p-hydroxybenzyl alcohols - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing p-hydroxybenzyl alcohols, and more particularly to a method for producing p-hydroxybenzyl alcohols by reacting phenols with formaldehyde.

[0002] p-Hydroxybenzyl alcohols are compounds useful as various organic chemicals such as medicines, agricultural chemicals and antioxidants, or as raw materials for synthesizing parahydroxybenzaldehyde and as resin modifiers.

[0003]

2. Description of the Related Art Heretofore, as a method for industrially obtaining p-hydroxybenzyl alcohols, a method of extracting p-hydroxybenzyl alcohols from a mixture of para and ortho hydroxybenzyl alcohols obtained by a reaction between phenols and formaldehyde has been proposed. (JP-A-54-36223), which is isolated from a mixture having a para: ortho ratio of 1: 2 to 50, and is used for the production of p-hydroxybenzyl alcohols. This is not an advantageous method.

In general, a para / ortho formation ratio of a synthesis method in which a phenol and formaldehyde are reacted in the presence of a basic catalyst is 1.0 or less, and there are many reports on a method for selectively producing orthohydroxybenzyl alcohol.

Methods for increasing the production ratio of p-hydroxybenzyl alcohols include (1) a method of reacting phenols with paraformaldehyde in the presence of a polyalkylene ether in the presence of a strongly basic catalyst (Japanese Patent Laid-Open No. 55-55). 141423
JP-A-56-16434), (2) a method in which an organic nitrogen compound having two or more nitrogen catalysts in a molecule is used as a basic catalyst to react phenols with paraformaldehyde.
Publication). However, even in these methods, the para-form content in the mixed hydroxybenzyl alcohol is 49% and 47%, respectively, and the para-form is less than the ortho-form.

[0006] A selective method for synthesizing p-hydroxybenzyl alcohol using cyclodextrin and modified cyclodextrin has also been reported (JCS, CC, 652, 198).
8). However, in this method, β-cyclodextrin is added 20 to 40 times, and sodium hydroxide is added 50 to the raw phenols.
The use of formaldehyde is 40 times that of formaldehyde, and the ratio of para / ortho is as high as 15.7, but it is not industrial in terms of cost.

A method using an acid type zeolite has also been disclosed (JP-A-63-307835). However, according to the inventors' additional tests, the product was dimethylolphenol or resin,
Since p-hydroxybenzyl alcohol cannot be obtained, this method cannot be said to be an effective synthesis method.

[0008]

An object of the present invention is to selectively produce industrially useful p-hydroxybenzyl alcohols using inexpensive raw materials.

[0009]

DISCLOSURE OF THE INVENTION The present inventors have found that a catalyst obtained by surface-modifying a basic zeolite in which the exchange point of zeolite is replaced with an alkali metal is extremely high in the formation of a para-form by the reaction of phenols with formaldehyde. The present inventors have found that a selectivity is exhibited, and have reached the present invention.

That is, the present invention provides a method for producing p-hydroxybenzyl alcohols by reacting phenols with formaldehyde, wherein a catalyst obtained by surface-modifying a zeolite whose exchange point is substituted with an alkali metal is used. This is a method for producing p-hydroxybenzyl alcohols.

(Raw Materials) The phenols used as the raw material of the present invention include, for example, phenol, 2-substituted phenol, 3-substituted phenol, 3- and 5-substituted phenols,
2- and 5-position substituted phenols. Here, the substituent of the phenol is, for example, a saturated or unsaturated hydrocarbon group having 1 to 3 carbon atoms, an aryl group, a hydroxyl group, a carboxyl group, a sulfone group, a halogen, or the like.

The formaldehyde source to be reacted with phenols in the present invention includes formalin, paraformaldehyde, hemiformal of a lower alcohol, and C 2 -C 5
Hemiformal, a polyhydric alcohol, of which paraformaldehyde is preferred. Formaldehyde is used in an amount of 0.1 to 1 mole of phenols.
It is 10 moles, preferably 0.5 to 3.0 moles.

(Catalyst) The catalyst used in the present invention is a zeolite whose exchange point is substituted with an alkali metal. As the zeolite, X-type zeolite, Y-type zeolite, ZSM-5, mordenite and the like can be used. The metal used for substitution is an alkali metal belonging to Group IA of the periodic table, of which cesium is particularly preferable. There is no particular limitation on the alkali metal source, and halides, hydroxides, nitrates and the like can be used.

In the present invention, the metal substitution of the zeolite is
Add an aqueous alkali metal solution to the zeolite, heat and stir, complete the process by replacing the aqueous metal solution with a new one several times and repeating the same operation.
Dry and bake.

In the present invention, those zeolites whose surfaces are modified with silicon, phosphorus, magnesium or the like to make the surface acid sites inactive or to control the pore diameter are used.

The surface modification is, for example, in the case of silica, a method in which silicon oxide is deposited on the zeolite surface, and the deposition method is a gas phase deposition method (Japanese Patent Application Laid-Open No. 62-52123) and a liquid phase method (Japanese Patent Application Laid-Open No. 1-108113) can be used. In such a catalyst siliconization, a siliconizing agent such as Si (OCH ₃ ) ₄ selectively reacts with hydroxyl groups on the surface, and the sites generally discussed as active sites of zeolite cannot be siliconized. Can be activated.

The siliconized zeolite in the present invention is obtained by siliconizing only the surface of the catalyst particles, and retains active sites in pores which cause a shape-selective reaction (synthesis reaction of p-hydroxybenzyl alcohols). And a non-shape-selective siliconized zeolite that inactivates the drinking of the outer surface of the catalyst particles that causes a non-shape selective reaction.

Further, in the siliconized zeolite, by controlling the amount of siliconization, the diameter of the pore entrance can be changed, and only a product which is sterically adapted can be selectively obtained.
This dramatically increases the selectivity of p-hydroxybenzyl alcohols compared to the same type of unsiliconized zeolite.

The amount of silicon used in the siliconization is too small to cover the outer surfaces of the catalyst particles,
If the amount is too large, the diameter of the pore entrance is narrowed, and the catalytic activity is greatly reduced. The book has a silicon content of 0.1 to 10% by weight, preferably 0.3 to 8.5% by weight, in the siliconized zeolite in the padding shade.

The amount of the catalyst used is 1 g of phenols.
The range is 0.5 to 10.0 g, preferably 1.0 to 5.0 g.

(Solvent) In the present invention, in addition to water, common organic solvents such as alcohols and hydrocarbons can be used as the solvent.

(Reaction conditions) The reaction was carried out in an alcohol solvent 100
1 to 50 g of zeolite per ml, preferably 5 to 30 g,
The phenol is used in an amount of 0.01 to 1 mol, preferably 0.05 to 0.3 mol, and the formaldehyde is used in an amount of 0.1 to 10 mol based on the phenol.
An equivalent amount, preferably 0.5 to 3 equivalents, is added, and the reaction is usually carried out by heating and stirring under a nitrogen atmosphere.

The reaction temperature is 20 to 130 ° C., preferably 30 to 130 ° C.
0 ° C.

The reaction time depends on the reaction temperature, the amount of the catalyst and the solvent, but is usually 3 to 30 hours. The obtained reaction product can be separated and purified into a para form and an ortho form by extraction separation and crystallization as required.

[0025]

The present invention will be described more specifically below with reference to examples and comparative examples. The formaldehyde-based yield and the selectivity of p-hydroxybenzyl alcohols in the description are defined by the following formula. Also, p-hydroxybenzyl alcohol, o-hydroxybenzyl alcohol,
Phenols were quantified by high performance liquid chromatography.

[0026]

(Equation 1)

[0027]

(Equation 2)

Reference Example (Preparation of Cesium-Substituted Zeolite) In a 1 liter eggplant-shaped flask, 19 g of X-type zeolite and 0.1 g of zeolite were added.
300 ml of a 5N cesium hydroxide aqueous solution was added, and the mixture was heated under reflux for 3 hours. This was cooled and allowed to stand, and the supernatant was removed by decantation. The cesium hydroxide aqueous solution was added again, and the same operation as described above was repeated twice.

After completion, the zeolite was filtered through a glass filter and washed with 1.5 l of distilled water. The solid obtained is 100
C., dried for 2 hours, and calcined at 400.degree. C. for 3 hours for use in the reaction.

(Reaction) 15.5 ml of isopropanol, 0.95 g (10 mmol) of phenol, 3.0 g of cesium-substituted zeolite X prepared as described above and 90
% Paraformaldehyde (0.13 g, 3.8 mmol) was added, the atmosphere was replaced with nitrogen, and the mixture was heated and stirred at 60 ° C for 24 hours.

After the reaction, the yield based on formaldehyde was 19.6%, and the para selectivity was 86.2%.

Example 1 (Catalyst preparation: surface modification) 3 g of the cesium-substituted zeolite prepared in the reference example was left in water for 3 days to allow water to saturate and adsorb thereto, and tetraethylorthosilicate / n-hexane = 1/9 ( (Volume) was added and stirred at room temperature for 3 hours. This was filtered and dried at 110 ° C. for 1 hour, then at 500 ° C. for 5 hours.
Fired for hours.

(Reaction) The reaction was carried out in exactly the same manner as in Reference Example, except that a cesium-substituted zeolite surface-modified by the above method was used as a catalyst. At the end of the reaction, the yield based on formaldehyde was 5.0%, and the para selectivity was 100%.

Example 2 A reaction was carried out in exactly the same manner as in Example 1 except that the reaction temperature was 80 ° C. After the reaction, the yield based on formaldehyde was 11.0%, and the para selectivity was 100%.

Comparative Example 1 A reaction was carried out under the same conditions as in Reference Example except that acid zeolite and H-ZSM5 were used as catalysts and water was used as a solvent. After the reaction, the yield based on formaldehyde was 7.3%, and the para selectivity was 0%.

Comparative Example 2 Cesium hydroxide 3.0 instead of zeolite as catalyst
g of isopropyl alcohol / water = 1/2
The reaction was carried out under the same conditions as in Reference Example except that (volume) was used. After the reaction, the yield based on formaldehyde was 71.9%, and the para selectivity was 41.5%.

[0037]

According to the method of the present invention, p-hydroxybenzyl alcohols can be produced with an unprecedentedly high selectivity.

Continued on the front page (72) Inventor Takato Nishiyama 8-3-1 Chuo, Ami-cho, Inashiki-gun, Ibaraki Sanritsu Oil Chemicals Co., Ltd. Tsukuba Research Laboratory (72) Inventor Kimiko Kaneko 8-3 Chuo, Ami-cho, Inashiki-gun, Ibaraki -1 Inside of Tsukuba Research Laboratory, Mitsubishi Oil Chemicals Co., Ltd. (56) References JP-A-4-275246 (JP, A) JP-A-63-307835 (JP, A) JP-A-63-307834 (JP, A) JP-A-54-36223 (JP, A) JP-A-55-141423 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C07C 39/11 C07C 37/20

Claims (1)

(57) [Claims] 1. A method for producing p-hydroxybenzyl alcohols by reacting phenols with formaldehyde, wherein a catalyst obtained by surface-modifying a zeolite substituted with an alkali metal is used. Manufacturing method.