JPS6013026B2 - Method for producing meta-aminophenols - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for selectively producing meta-aminophenols by reacting resorcinol with ammonia or amines in a gas phase method.

Meta-aminophenols are used as pharmaceuticals, agricultural chemicals, dyes, compounding agents for synthetic resins, or intermediates for their production. Conventionally, in the method of producing aromatic amines by reacting phenols with ammonia or amines in a gas phase method, various metal oxides are known to be effective as catalysts for this reaction (for example, Tokuko Showa 4
2-23571 Publication, Hakama Publication No. 46-23052, Special Publication No. 46-23053, Tsubaki Publication No. 46-418
Special Publication No. 49-14737, Special Publication No. 14737, Special Publication No. 14737
-14738, Japanese Patent Publication No. 49-29176, etc.).

The catalysts proposed in these patent publications have been shown to be effective in the amination reaction of polyhydric phenols, and among dihydric phenols, these catalyst systems have been used for the amination reaction of hydroquinone. It is stated that when used, various phenylene diamines are selectively obtained. However, meta-aminophenols cannot be selectively produced even if the amination reaction of resorcinol is carried out in the presence of these catalysts. The present inventors investigated a method for selectively producing meta-aminophenols/groups by gas-phase amination reaction of resorcinol, and found that the reaction was carried out in the presence of a catalyst containing an oxide of a specific element as a catalyst. The inventors have discovered that this object can be achieved by the following methods, and have arrived at the present invention.

That is, the present invention provides a method for treating sorcin'a} with ammonia, a primary amine or This is a method for producing meta-aminophenols, which is characterized by reacting a secondary amine 'b' by a gas phase method.

In the method of the present invention, the catalyst used is an oxide of at least one element selected from the group consisting of phosphorus, zinc, vanadium, molybdenum and tungsten.

As a catalyst, ``oxides of these elements can be used alone, or can be used as a composite catalyst consisting of oxides of these elements and other catalyst components. Alternatively, a composite catalyst consisting of oxides of these elements and other catalyst components may be used on various carriers, such as activated carbon, activated alumina, silica-alumina, silica gel, titania, zirconia, thoria, activated clay tocerite, talc, and other carriers. It can also be used in a state where it is supported on a carrier. Among these catalysts, it is preferable to use a catalyst in which an oxide of the above element is supported on a carrier. Methods for preparing the catalyst include, for example, a method in which a carrier is impregnated with a solution of a water-dropping compound of the above element, dried, and then calcined to form an oxide; Examples of phosphorus oxides include a method in which a base such as ammonia is applied to a mixed solution of phosphorus to co-precipitate it as an insoluble compound, which is then dried and calcined to form an oxide. Diphosphorus trioxide, diphosphorus tetroxide, diphosphorus pentoxide, etc. Zinc oxides include zinc oxide, zinc suboxide, etc. Vanadium oxides include vanadium monoxide, divanadium trioxide, vanadium dioxide, etc. , divanadium pentoxide, etc.; examples of molybdenum oxides include molybdenum dioxide, dimolybdenum pentoxide, molybdenum trioxide, etc.; examples of tungsten oxides include tungsten dioxide, tungsten trioxide, etc. Among the oxides of these elements, it is preferable to use a catalyst containing an oxide of phosphorus.In the method of the present invention, ammonia or amines used as a reaction raw material include ammonia,
Primary amine or secondary amine.

Specifically, gaseous ammonia or aqueous ammonia is used as the ammonia, and examples of the primary amine include methylamiso, ethylamine, n-propylamine, and n-propylamine.
butylamine, sec-butylamine, amylamine,
Examples include hexylamine, heptylamine, octylamine, nonylamine, decylamine, dodecylamine, benzylamine, aniline, toluidine, etc., and secondary amino acids include dimethylamine, diethylamine, di-n-propylamine, diisopropylamine, Examples include di-n-butylamine, disec-butylamine, diamylamine, dihexylamine, diheptylamine, dioctylamine, didodecylamine, etc. Among these ammonia or amines,
It is particularly preferred to apply the method of the invention to the production of aromatic primary amines using ammonia. The amount of ammonia, primary amine or secondary amine used is 1 mol or more per 1 mol of resorcin, preferably 5 to 30
It is in the molar range. If ammonia, primary amine or secondary amine is used in excess, it is recovered from the mixture after the reaction and recycled for use. In the present invention, the reaction between resorcinol and ammonia or amines is carried out by a gas phase method.

Examples of the contacting method include a fixed bed method, a fluidized bed method, and a moving bed method, but the fixed bed method is usually adopted. The reaction temperature is usually 250 to 400
30, preferably 280 to 350 qo. Although the reaction can be carried out under normal pressure, increased pressure or reduced pressure, it is preferably carried out under normal pressure or increased pressure. In addition, the space velocity (GHSV) of the raw material mixture gas is usually 200, 250, preferably 360, 18
It is in the range of 0 valence r-1. Further, during the reaction, the gas of the raw material mixture can be diluted with a gas inert to the reaction or vapor of a solvent inert to the reaction. In the method of the present invention, the desired product can be obtained by treating the reaction product mixture after the completion of the reaction according to a conventional method such as a distillation method or a crystal plate method.

Next, the method of the present invention will be specifically explained using examples.

Example 1 The surface area is 270 mm and the average pore diameter is 140 A.
A phosphorus oxide catalyst was prepared by supporting 8 hol% of phosphoric acid on silica gel and calcining it at 500 qo for 3 hours under air circulation.

This catalyst 20' is connected to a Virex reaction tube (3W cape x
A 40' unglazed Raschig ring was filled in the upper layer as a heating element. The temperature of the catalyst layer was raised to 320°C by flooding with an electric furnace.
After replacing the inside of the reaction tube with ammonia gas, the reaction was carried out by continuously supplying a 6% by weight aqueous solution of resorcinol 6 evenings/hour and ammonia gas in an amount equivalent to 1 pmol of resorcinol (GHSV1200/ Time). 3 after the start of the reaction
When the reaction mixture from the 5th hour to the 5th hour was analyzed by gas chromatography, the rate of change of resorcinol was 31.
%, and the selectivity to meta-aminophenol was 97%. Example 2 In place of the phosphorus oxide catalyst in Example 1, a zinc oxide catalyst prepared by supporting 8 hol% of zinc nitrate on the same silica gel by an impregnation method and then calcining it at 50°C for 3 hours under air circulation was used. The reaction between resorcin and ammonia was carried out in the same manner as in Example 1.

Analysis of the product revealed that the conversion rate of resorcin was 20%.
The selectivity of meta-aminophenol was 90%. Examples 3 to 5 Vanadium pentoxide (Example 3) and molybdenum pentoxide (Example 4) were prepared using the same method as described in Example 1 as a catalyst preparation method.
) or tungsten trioxide (Example 5), each of which was supported at 8 hol% on silica gel, was prepared.

In Example 1, the reaction between resorcinol and ammonia was carried out in the same manner as in Example 1, except that these catalysts were used instead of the phosphorus oxide catalyst. Meta-aminophenol was the main product in both cases. The results are shown in Table 1. Table 1 Comparative Example 1 In Example 1, a reaction between resorcinol and ammonia was attempted in the same manner as in Example 1 except that unglazed Raschig ring 20 was filled instead of the phosphorus oxide catalyst, but meta-aminophenol was No resorcin was obtained, and the entire amount of resorcin was recovered.

Comparative Example 2 The reaction between resorcinol and ammonia was carried out in the same manner as in Example 1, except that a silica-alumina catalyst (alumina content: 15%) was used instead of the phosphorus oxide catalyst.

Gas chromatography of the product after 5 hours
When analyzed, the conversion rate of resorcin was 47% and the selectivity of meta-aminophenol was 22%.

Example 6 In Example 1, the reaction temperature was 350 qo, and 6
The reaction between resorcin and ammonia was carried out in the same manner as in Example 1, except that the feed rate of the aqueous solution of resorcin of % by weight was changed to 2 evenings/hour (GHSV of all gases: 420/hour).

The conversion rate of resorcinol was 55% and the selectivity of meta-aminophenol was 83%. Example 7 In Example 1, the reaction temperature was changed to 250 qo, and the feed rate of the 6% by weight resorcinol aqueous solution was changed to 12 evenings/hour (
The reaction between resorcinol and ammonia was carried out in the same manner as in Example 1, except that the GHSV of all gases was 2100 hours).

The conversion rate of resorcinol was 12% and the selectivity of meta-amidium/phenol was 89%. Example 8 In Example 1, resorcinol and ammonia were combined in the same manner as in Example 1 except that y-alumina was used instead of silica gel as the catalyst carrier and a phosphorus oxide catalyst prepared in the same manner as in Example 1 was used. The reaction was carried out.

As a result, the conversion rate of resorcin was 36%, and the selectivity of meta-aminophenol was 91%. Example 9 The reaction between resorcinol and ammonia was carried out in the same manner as in Example 1, except that methylamiso was used instead of ammonia gas.

Claims (1)

[Claims] 1. Resorcinol (a) and ammonia, a primary amine or A method for producing meta-aminophenols, which comprises reacting a secondary amine (b) by a gas phase method. 2. The method according to claim 1, wherein the catalyst is a catalyst in which an oxide of at least one element selected from the group consisting of phosphorus, zinc, vanadium, molybdenum, and tungsten is supported on a carrier. 3. The method according to claim 1 or 2, wherein the reaction is carried out at a temperature of 250 to 400°C.