JPS58192843A - Preparation of alkyl group-substituted alkoxyphenol - Google Patents

Abstract

PURPOSE:To obtain the titled compound useful as a raw material for alkyl group-substituted bivalent phenols, by bringing a specific alkoxyphenol into contact with a lower alcohol in the vapor phase in the presence of a catalyst consisting essentially of iron oxide. CONSTITUTION:An alkoxyphenol having one or more hydrogen atoms directly linked to the carbon atom adjacent to the carbon atom having a hydroxyl group, preferably 4-methoxyphenol, 3-methoxyphenol or a substitution product thereof with a methyl group is brought into contact with a lower alcohol, preferably methanol, in the vapor phase in the presence of a one-component type catalyst, consisting of 50wt% or more iron oxide essentially or multielement type catalyst, e.g. binary or ternary system, consisting of germanium oxide, silicon oxide or chromium oxide, at 250-400 deg.C, 0.1-5hr<-1> liquid space velocity and reduced pressure-10kg/cm<2>.G pressure to give the aimed compound. EFFECT:The reduction in catalyst activity is light, and the slife is long. Thus, the decomposition of the alcohol can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing alkyl-substituted alkoxyphenols selectively and in high yield from the reaction of alkyl diphenols and lower alcohols.

Alkyl-substituted dihydric phenols can be easily obtained from alkyl-substituted alkoxyphenols by ether cleavage.

Alkyl group-substituted dihydric phenols, alkyl group-substituted dihydric phenols having at least one alkyl group bonded to the carbon atom adjacent to the hydroxyl group-bonded carbon atom are used for pharmaceuticals, agricultural chemicals, and resins. It is useful as an intermediate in the production of compounded drugs.

Conventionally, methods for producing alkyl group-substituted dihydric phenols include sulfuric acid, phosphoric acid, hydrogen fluoride, ion exchange resin,
A method of contacting dihydric phenols and olefins in a liquid phase in the presence of hydrochloric acid or other acidic catalysts [U.S. Patent No. 2,
No. 051,474, U.S. Pat. No. 2,544.81
Specification No. 8, U.S. Patent No. 2,831,817 Meiwa]
, a method in which dihydric phenols and alcohol are brought into contact in a liquid phase in the presence of sulfuric acid, hydrogen fluoride, phosphoric acid, oxalic acid, or other acidic catalysts [Hl) Yeyer etal, Monat
sh, 53/54.746 (1929), W.
S, Calcott SJ, Am, Chem,
Soc.

61.1010 (1939)) have been proposed.

The former method cannot produce polymethyl group-substituted dihydric phenols, which are the most useful among alkyl group-substituted dihydric phenols. In addition, it cannot be said that either method has high selectivity to alkyl group-substituted dihydric phenols and high yield thereof.

In addition, U.S. Patent No. 4,060,561 includes 4
-Methoxyphenol and methanol, with magnesium oxide or magnesium oxide as the main component, and aluminum oxide, uranium oxide, titanium oxide, cerium oxide,
A method has been proposed in which the reaction is carried out in the gas phase at a temperature of 350 to 550° C. in the presence of a catalyst containing manganese oxide, zinc oxide or iron oxide as a promoter component. However, this method has the drawback that not only is the catalyst activity low and the selectivity to polyalkylhydroquinone and its yield low, but also that methanol is significantly lost due to decomposition during the reaction, and polymethylhydroquinone cannot be produced on an industrial scale. It is difficult to say that this is an excellent method for manufacturing.

The present inventors investigated a method for selectively producing alkyl group-substituted alkoxyphenols in high yield by improving the above-mentioned drawbacks of conventional methods. The inventors have discovered that the above object can be achieved by bringing specific alfukidiphenols into contact with alcohol in the gas phase, and have arrived at the present invention. Furthermore, according to the present invention, alkylation occurs selectively to the carbon atom adjacent to the hydroxyl group-bonded carbon atom, the catalyst has high activity, and alkyl group-substituted alkoxyphenols can be selectively obtained in high yield. In addition, the loss of alcohol due to decomposition during the reaction is significantly lower than that of conventional catalysts, the decrease in catalyst activity is small, and the catalyst has a long life. Furthermore, by acid decomposition of the alkyl group-substituted alkoxyphenols obtained by the method of the present invention, the corresponding alkyl group-substituted dihydric phenols can be obtained in high yield. An alkoxyphenol having at least one hydrogen atom bonded to a carbon atom (a) and a lower alcohol (b) are brought into contact in a gas phase in the presence of a catalyst (Cl) containing iron oxide as a main component. This is a method for producing alkyl group-substituted alkoxyphenols, which is characterized by the following.

The alkoxyphenols (a) used as raw materials in the method of the present invention are alkoxyphenols having at least one hydrogen atom bonded to a carbon atom adjacent to a hydroxyl group-bonded carbon atom, and specifically, It is an alkoxyphenol having at least one hydrogen atom bonded to a carbon atom adjacent to a carbon atom, or a lower alkyl group-substituted product thereof. Among these alkoxyphenols (a), alkoxyphenols having at least two or more hydrogen atoms bonded to a carbon atom adjacent to a hydroxyl group-bonded carbon atom or an alkyl group-substituted product thereof are preferable. Here, the alkoxyl group is a lower alkoxyl group, and the a numeral has 1 carbon atom.
-4 alkoxyl group, methoxyl group, ethoxyl group, n-propoxyl group, inpropoxyl group,
n-butoxyl group, 580-butoxyl group, tart-
Examples include butoxyl group, and substituted alkyl groups are usually alkyl groups having 1 to 2 atoms, and specific examples include methyl group, ethyl group, n-propyl group, isopropyl group, etc. can do. Among these alkoxyphenols having a lower alkyl group, alkoxyphenols having a methyl group are preferably used. Specifically, the raw material alfkidiphenols (a) include 4-methoxyphenol, 4-methoxy-2-methylphenol, 4-methoxy-2,3-dimethylphenol, 4-ethoxyphenol, and 4-ethoxyphenol. 4-alkoxyphenol such as 2-methylphenol, 4-isopropoxyphenol, 4-tert-butoxyphenol or its lower alkyl group f
l1 body, 3-methoxyphenol, 5-methoxy-2-
5-alkoxyphenols such as methylphenyl, 3-methoxy-4-methylphenol, 3-ethoxyphenol, 3-isopropoxyphenol, 3-tert-butoxyphenol or lower alkyl group-substituted products thereof;
2-methoxyphenol, 2-methoxy-3-methylphenol, 2-methoxy-4-methylphenol, 2-
Ethoxyphenol, 2-inpropoxyphenol,
Examples include 2-alkoxyphenol such as 2-terj-butoxyphenol, or a lower alkyl group-substituted product thereof. The alkoxyphenol (a)
In Nouchi, it is preferable to use 4-alkoxyphenol, 5-alkoxyphenol, 2-alkoxyphenol, or a methyl group-substituted product thereof, and in particular, use 4-methoxyphenol, ro-methoxyphenol, or a methyl group-substituted product thereof. is preferred.

Lower alcohol (b) used in the method of the invention
is usually alconyl having 1 to 6 carbon atoms,
Specifically, methyl alcohol, ethyl alcohol, n-
Examples include propyl alcohol and isopropyl alcohol. Among these lower alcohols, methyl alcohol is preferably used. The proportion of the lower alcohol used is usually about 0.5 to about 10 mol per hydrogen atom bonded to the carbon atom adjacent to the phenolic hydroxyl group-bonded carbon atom in the molecule of the alkoxyphenol (2L); Preferably about 1
The amount ranges from none to about 5 mol, particularly preferably from about 2 to about 5 mol.

The catalyst (C) used in the method of the present invention is a catalyst containing iron oxide as a main component. Here, the catalyst containing iron oxide as a main component refers to a catalyst containing iron oxide in an amount of usually 50% by weight or more, preferably 70% by weight or more, particularly preferably 90% by weight or more. It is a component-based catalyst or a multi-component catalyst. These catalysts containing iron oxide as a main component include catalysts consisting of a single iron oxide component; binary catalysts containing iron oxide and a second catalyst component and containing iron oxide as a main component; Mention may be made of multi-component catalysts such as ternary catalysts containing iron, a second catalyst component and a third catalyst component and containing iron oxide as a main component. The second catalyst component includes gallium oxide, germanium oxide, silicon oxide,
Examples include at least one metal oxide selected from the group consisting of yttrium oxide, niobium oxide, hafnium oxide, tantalum oxide, and bismuth oxide, and among these, germanium oxide, gallium oxide, and silicon oxide. It is preferable to use at least one metal oxide selected from the group consisting of: a catalyst with excellent effects of the present invention, and germanium oxide is particularly preferable. The third catalyst component is at least one selected from the group consisting of red gram oxide, ill oxide, aluminum oxide, chromium oxide, zirconium oxide, a basic alkali metal compound, and carbon.
For example, a ternary catalyst containing iron oxide as a main component and blended with these third catalyst constituents can suppress a decrease in catalyst activity, resulting in a long-life catalyst. Among these third catalyst components, at least one selected from the group consisting of magnesium oxide, aluminum oxide, chromium oxide, and basic alkali metal compounds is preferred. The mixing ratio of the second catalyst component is usually about 0.0 as the metal atom of the metal oxide of the second catalyst component per 1 gram atom of iron atom of iron oxide.
0.03 to about 0.03 g atoms, preferably about 0.005
and about 0.15 gram atom. Further, when the third catalyst component is blended, the blending ratio is usually about 0.0001 to about 0.1 mole, preferably about 0.0001 to about 0.1 mole, preferably about ooi to about 0.05 mole. Among the aforementioned catalysts containing iron oxide as a main component, when a multicomponent catalyst containing iron oxide as a main component is used,
It is preferable because it has high reactivity, high ortho-position selectivity in the alkylation reaction, and can suppress alcohol decomposition.

In the method of the present invention, the catalyst containing iron oxide as a main component is usually used as a fixed bed catalyst by filling it in a reaction tube or a packed column. At that time, these catalysts
It is filled in an appropriate shape, such as powder, granules, spheres, tablets, or lumps. The length of the reaction tube or packed column filled with the fixed bed catalyst and the cross-sectional area perpendicular to the flowing gas are appropriately determined depending on the liquid hourly space velocity of the feed gas mixture and the linear velocity of the feed gas mixture.

In the method of the present invention, the alfukidiphenols (
The reaction between a) and the lower alcohol (b) is carried out by bringing them into contact with each other under heating in the gas phase in the presence of the catalyst (C1). It is possible to adopt a method in which only a gas mixture is brought into contact with the catalyst, or a method in which a gas mixture consisting of the alfukidiphenols, the lower alcohol, and a gas inert to the reaction is brought into contact with the catalyst. Examples of diluent gases that are inert to the reaction include nitrogen, helium, argon, returned acid gas, and water.
, benzene, toluene, quinolene, n-hexane, n-
Examples include heptane and n-tecan.

In carrying out the method of the present invention, the gaseous mixture containing the raw materials and the catalyst may be brought into contact with each other in the gas phase by a solid bed method, a moving bed method, or a fluidized bed method. However, it is preferable to employ a fixed bed contact method as a production method on an industrial scale.

In the method of the present invention, the reaction is carried out under heating,
The temperature during the reaction is usually about 25°C to about 500°C.
Preferably the temperature ranges from about 300 to about 450°C, particularly preferably from about 300 to about 400'C. Also,
The liquid hourly space velocity (LHSV) during the reaction is usually about 0.01.
from about 50 hr-', preferably from about 0.05 to about 11] hr', particularly preferably from about 0.1 to about 5. The pressure during the reaction is usually in the range of reduced pressure to about ', l Q kg / (: M
, preferably about 0 to lq) 1Q kg 7cm
2-0, particularly preferably about 0 to 5 kq/α
The range is 2.

In the method of the present invention, a reaction mixture can be obtained by condensing the vapor of the gas mixture exiting the reactor, and a reaction product mixture can be obtained by removing the diluent from the reaction mixture.

Unreacted lower alcohols and unreacted alkoxyphenols can be recovered from this reaction product mixture by means such as distillation, and these can be recycled and reused in the reaction system. The crude lower alkylated product obtained as a high boiler is further separated into products such as mono-lower alkylated products and tri-lower alkylated products by conventional means such as rectification, extraction, and adsorption. The mono-lower alkyl intermediate product can be recycled and reused, if necessary, by supplying it to the reaction system together with the raw material alkoxyphenol (al) to obtain the desired polyalkylated product.

According to the method of the present invention, it is possible to selectively lower alkylate the carbon atoms adjacent to the hydroxyl group-bonded carbon of the raw material No. 11 alfukidiphenols, and further suppress the decomposition reaction of the lower alcohol during the reaction. I can do it. Moreover, during the reaction, the activity of the catalyst may decrease <<, the advantage of long catalyst life)! , 1.

By reacting the alkyl-substituted alkoxyphenols obtained by the method of the present invention with a hydrohalic acid such as hydroiodic acid or hydrobromic acid under heating, the corresponding alkyl-substituted dihydric phenols can be highly obtained in high yield. Among the above-mentioned hydroiodic acids, hydroiodic acid is particularly preferred, and the temperature during the ether cleavage reaction is usually in the range of 200 to 100°C, preferably 30 to 80°C.

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

Example 1 After dissolving 202.0 g of ferric nitrate nine hydrate in 21 distilled water, 25% ammonia water was gradually added to reduce the pH of the liquid.
H was set to 7. The generated precipitate was washed with water and filtered.

1.65 g of germanium dioxide was added to this and kneaded for 1 hour using an automatic mortar. This was dried at 90°C for a day and night, and then calcined at 450°C for 3 hours to prepare a catalyst consisting of iron oxide and germanium oxide. When the catalyst thus prepared was analyzed by atomic absorption spectroscopy, it was confirmed that the atomic ratio of iron:germanium was 97:3.

20rnl of catalyst crushed into 6-10 meshes with inner diameter of 20mm
After filling a mm Pyrex reaction tube, the temperature was 330°C.
heated to. After reaching a predetermined temperature, a mixture of methanol/4-methoxyphenol with a molar ratio of 5 was added at 14 ml/h.
The reaction was carried out by feeding at a rate of r (LH8VO, 7hr-1). The results are shown in Table 1.

Example 2 In the catalyst preparation method of Example 1, germanium dioxide 1.
A catalyst consisting of iron oxide and silicon oxide (atomic ratio of 97:3) was prepared in the same manner except that instead of adding 65 g of silica sol, 9.5 g of silica sol containing 1% by weight of silicon dioxide was added. The reaction results are shown in Table 1.

Table 1 Example 6 After dissolving 202.0 g of ferric nitrate nine hydrate in 24-distilled water, 25% ammonia water was gradually added to adjust the pH of the liquid.
was set as 7. The generated precipitate was washed with water and filtered. Add to this 2.4 g of germanium dioxide and 2.3 g of chromium nitrate nonahydrate.
was added and kneaded for 1 hour using an automatic mortar. This is 90
It was dried at °C for a day and night, and then calcined at 600 °C for 3 hours to prepare a ternary catalyst consisting of iron oxide, germanium oxide, and chromium oxide.

The catalyst thus prepared was analyzed by atomic absorption spectroscopy, and the atomic ratio of pig iron: germanium: chromium was 94.5: 4.5.
It was confirmed that it was 1.0.

20ml of catalyst crushed into 6-10 meshes with inner diameter';)
After filling into Qmm Pyrex reactor, 330°
It was heated to C. After reaching a predetermined temperature, a mixed solution of 4-methoxyphenol:methanol:H2O in a molar ratio of 1:5:2 was supplied at a rate of 12 ml/hr to carry out a reaction.

Table 2 shows the results 50 hours and 450 hours after the start of the reaction.

Table 2 Example 4 The same Feo-Geo23 catalyst prepared in Example 1 was used to methylate 3-methoxyphenol. The reaction temperature was 310'C, LH8V was set to 1=O, and 1:
The molar ratio was 5:2. The results are shown in Table 3.

Table 5 Comparative Example 1 Magnesium oxide (manufactured by Kyowa Chemical, Kiyowa Magben 150
), the reaction humidity was 510°C, and LH8V. The results are shown in Table 4.

Table 4 Reference Example 1 Highly purified 2.6-
Dimethyl-4-methoxyphenol was obtained. Next, 20 g of this 2,6-dimethyl-4-methoxyphenol was dissolved in 200 g of acetic acid, and 57% of hydroiodic acid was added to this.
45 g of the aqueous solution was added to 170 g of the solution and refluxed under nitrogen atmosphere.

In about 6 hours, the raw material 2,6-dimethyl-4-methoxyphenol was completely reacted according to the following formula.

After distilling off acetic acid from the product, it was dissolved by adding benzene and water in an equidistant manner, oil and water were separated at 50'C, and the aqueous layer was cooled with ice water to form crystals of 2,6-dimethylhydroquinone 14.
g was precipitated.

Applicant Mitsui Petrochemical Industries Co., Ltd. Agent Yamaguchi Writ of amendment (method) % formula % (7 1 Indication of case 1982 Patent Application No. 203493 2 Name of the invention Manufacturing method 5 Relationship with the case of the person making the amendment Patent applicant (588) Mitsui Petrochemical Industries Co., Ltd. 4 Agent 100 5 Date of amendment order May 31, 1980 Date of dispatch 6 Number of inventions increased by amendment 07 The amendment shall be made to ``Process for producing phenols'' in the title of the invention column of the specification subject to amendment.

Claims (1)

[Scope of Claims] (1) An alkoxyphenol having at least one hydrogen atom bonded to a carbon atom adjacent to a hydroxyl group-bonded carbon atom (a) and a lower alcohol (b) are combined with iron oxide as the main component. A method for producing alkyl group-substituted alkoxyphenols, which comprises contacting them in a gas phase in the presence of a catalyst (e). (2) The method according to claim (1), wherein the alkoxyphenol (a) is 4-methoxyphenol, 5-methoxyphenol, or a methyl group-substituted product thereof. (5) The method according to claim (1), wherein the lower alcohol is methanol. (4) The method of claim (1), wherein the reaction temperature is maintained in the range of about 250 to about 400°C. 5. The method of claim 1, wherein the molar ratio of lower alcohol to alkoxyphenols in the feed gas is maintained in the range of about 2 to about 7. 6. The method of claim 1, wherein the liquid hourly space velocity of the feed gas is maintained in the range of about 0.1 to about 5 hr-'.