JPS58146523A - Preparation of alkylphenol - Google Patents

Abstract

PURPOSE:To suppress the decomposition of alcohols in the orthoalkylation of a phenol having H at the o-position, to improve the selectivity of the o-alkylation, and to improve the effective utilization of alcohol, by feeding the phenol dividedly to the reaction system. CONSTITUTION:An o-alkylphenol (e.g. 2,6-dimethylphenol) is prepared by reacting a phenol of formula (R1-R4 are H, 1-4C hydrocarbon group, OH, phenyl, naphthyl, etc.) having H at the o-position (e.g. phenol, cresol, etc.) with an alcohol (e.g. methanol, ethanol, etc.) in the presence of a catalyst (e.g. a catalyst containing aluminum oxide). In the above process, the phenol used as a raw material is introduced dividedly into the reaction gas stream passing through the catalyst layer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing orthoalkylphenols by reacting phenols and alcohols.

In particular, the present invention provides a method for producing alkylphenols from alcohols and phenols having at least one hydrogen atom in the ortho position, by dividing the raw material phenols into a reaction gas stream passing through a catalyst bed. This is an industrially advantageous method that significantly improves the aluminum efficiency.

It is known that alkylphenols, especially the orthoalkylated product 2,6-dimethylphenol, are important as raw materials for the production of polyphenylene phenol (PPE), a useful plastic.

It is also known that a great deal of research has been conducted on alkylphenols for use as raw materials for resins, plasticizers, antioxidants, fungicides, and agricultural chemicals.

Alkylation methods for phenols have already used catalysts such as aluminum oxide, magnesium oxide, manganese oxide, iron oxide, chromium oxide, zeolite, etc., as well as various ingredients added to them, to bring phenols and alcohols into contact. There are known methods for reacting, but when considering the overall performance of the catalyst, none of these methods are sufficient in terms of activity, selectivity, induction period, lifespan, etc., and they are not satisfactory catalysts. sea bream.

Generally, when producing orthoalkylphenols using the above-mentioned catalysts, these methods involve mixing all of the raw materials, phenols and alcohols, and passing the mixture into a reaction tube filled with a catalyst.

At this time, the reaction temperature is 4, which varies depending on the catalyst used, but
A temperature of 800 to 570°C is generally used.

The present inventors continued to study the above reaction method, and as a result, the present inventors produced orthoalkylphenols by reacting phenols having at least one hydrogen atom at the ortho position with alcohols in the presence of a catalyst 1'. In this case, it was found that if a phenol having at least one hydrogen atom in the ortho position is present in the catalyst layer, the decomposition of the alcohol, which lowers the selectivity of alkylation, can be suppressed.

To specifically illustrate these points, Figure 1 shows the changes over time in the residual rate of phenol and 0-cresol and the decomposition rate of methanol when 2,6-xylenol is synthesized from phenol and methanol. . As is clear from Figure 1, the decomposition of alcohols such as mechnol in the reaction becomes more likely when the amount of phenols having at least one hydrogen atom in the ortho position near the exit of the catalyst layer decreases. It shows.

As a result of intensive research on the above points, the present inventors have found that in a method for producing orthoalkylphenols by reacting phenols having at least one hydrogen atom at the ortho position with alcohols in the presence of a catalyst, By dividing and supplying the raw material phenols into the gas flow passing through the catalyst bed, the decomposition of alcohols is suppressed, and the selectivity of orthoalkylation is improved, thereby significantly increasing the effective utilization rate of alcohols. The present inventors have discovered that the method of the present invention can be obtained.

In the method of the present invention, the method of dividingly supplying the phenols having one hydrogen atom in the ortho position is such that the phenols are dividedly supplied within the range of the catalyst layer into the reaction gas flow passing through the catalyst layer. If so, there are no particular restrictions on the interval, the number of supply points, etc., and various methods can be applied.For example, there is a method of directly supplying to the reaction tube, a method of dividing the reaction tube into multiple stages and supplying between them, etc. be.

The distribution amount and spacing of phenols having at least one hydrogen atom at the ortho position vary depending on the phenol used, the catalyst, and the structure of the reactor, and cannot be discussed uniquely. In a method for producing orthoalkylphenols by reacting phenols having at least one hydrogen atom with alcohols in the presence of a catalyst, raw phenols are introduced into a reaction gas stream passing through a catalyst bed. This is a method for producing orthoalkylphenols, which is characterized by supplying them in portions.

The phenols used in the method of the present invention are phenolic compounds having at least one hydrogen atom in the ortho position, and have the general formula (wherein R1-R4 are hydrogen, a C1-4 hydrocarbon group, a hydroxyl a group or unsubstituted or substituted phenyl,
It is an aromatic hydrocarbon group such as naphthyl. ).

Examples of such compounds include phenol, cresols, xylenols, trimethylphenol a, ethylphenols of each m, n-11 days 0-1 tert-
Examples include butylphenols, phenylphenols, naphthylphenols, and the like.

Similarly, phenolic compounds in which one or more true functional groups are substituted with aromatic groups may also be used.

The alcohol used in the method of the present invention is charcoal [Math.
-4 lower alcohols, such as methanol, ethanol, n-propanol, 180-propatool, n
-butanol, IB〇-butanol, tert-butanol, etc.

Catalysts that can be used in the method of the invention include, for example, aluminum oxide-containing catalysts, magnesium oxide-containing catalysts, manganese oxide-containing catalysts, iron oxide-containing catalysts, and zeolite-containing catalysts.

That is, aluminum oxide-containing catalysts include aluminum oxide alone or those containing aluminum oxide as a main component and containing, for example, silicon oxide, and magnesium oxide-containing catalysts include one or more selected from magnesium oxide. .

Further, the manganese oxide-containing catalyst includes manganese oxide alone or one containing manganese oxide as a main component, and one or more selected from magnesium oxide, silicon oxide, iron oxide, iron oxide, etc.

The iron oxide-containing catalyst may include iron oxide alone or iron oxide as a main component, and one or two selected from silicon oxide, chromium oxide, zinc oxide, manganese oxide, alkali metals, alkaline earth metals, etc. This includes the above.

Furthermore, as zeolite-containing catalysts, protons, lanthanum, nickel, copper, manganese, chromium, cobalt, boron, zinc, cadmium, alkali metals, and alkaline earth metals are added to the central anion void of various zeolites such as X-type and Y-type.
These include zeolites that have undergone cation exchange in more than one species.

As raw materials for various oxides used in these catalysts, conventional compounds are used.

The catalyst can be prepared by mixing various raw materials, adding a small amount of water, and kneading with a kneader, mixer, etc., or by adding a basic component to an aqueous solution of various raw materials and co-precipitating it as an insoluble precipitate. After that, filter, wash and dry as necessary.
Ordinary preparation methods such as firing and molding methods can be used as they are. In addition, when carrying out the method of the present invention in which a normal ion exchange method may be applicable to a zeolite-containing catalyst, the appropriate molar ratio of phenols and alcohols to be supplied is 4:1 to 1:10. , 8
:1 to 1:8 is more preferable.

The method of carrying out the reaction by mixing water into the reaction raw materials has the effect of further extending the life of the catalyst and suppressing unnecessary decomposition of alcohols.

In the method of the present invention, the reaction temperature is 800-570C1
Preferably it is in the range of 810 to 580°C.

If the reaction temperature is lower than this range, the conversion rate will be insufficient in the normal reaction format and it is not practical.If the reaction temperature is set higher than this range, the reaction can be carried out even if the selectivity decreases, and the reaction format can also be fixed bed, moving bed, Both fluidized beds are possible, but fixed beds are common.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited only to the contents of these Examples.

The catalyst performance in Examples 1 to 6 is shown by the conversion rate and orthomethylation selectivity, and each is defined by the following formula.

Conversion rate (moles) = Conversion rate of phenol (moles) Ormethylation selectivity (methanol standard) Methanol supplied (moles) = Unreacted methanol (moles) x 100 Orthomethylation selectivity (phenol standard) Methanol decomposition rate Examples The catalyst performance in Examples 6 to 7 is indicated by the conversion rate of the raw material phenols and the selectivity of the target product, and each is defined corresponding to the above formula.

Example 1 The reaction apparatus used for alkylation consisted of a quartz glass reaction tube with a length of 800 m and an inner diameter of 15 mm, and an
Eight tubes are installed at equal intervals in the crR, allowing raw material phenol to be supplied.

A portion of the raw material phenol and methanol are supplied from the pipe A1 at the inlet of the catalyst layer.

The remainder of the raw material phenol was stored in the center of a two-neck (mu2) quartz glass reactor installed at equal intervals from the inlet of the catalyst layer, containing 10 to 20 meshes of catalyst 20- and silicon carbide 20-. The mixture was filled and placed in an electric furnace.

The catalyst was commercially available magnesium oxide, and after installing it in the first stage equipment, the temperature of the catalyst layer was heated to 480°C.

Next, phenol, methanol and water (supplied molar ratio 1:
Table 1 shows the results of feeding 5:1.7) in the following manner.

1 44 5
902 22
08 22
0th 11th! As Comparative Example 1, the same procedure as in Example 1 was carried out except that phenol was not distributed and supplied but was supplied all at once from the A1 supply pipe.

Example 2 The catalyst used was manganese dioxide, and the reaction temperature was 480℃.
The reaction was carried out in the same manner as in Example 1 except that the temperature was changed to .degree. C., and the results are shown in Table 2.

I did the same thing as step 2! ! Example 8 A reaction was carried out for the purpose of producing 2,6-xylenol f using the same method as in Example 1 except that the catalyst used was ferric oxide and the reaction temperature was 400°C. The same procedure as in Example 8 was carried out, except that the mixture was not supplied as shown in Table 8, but instead was supplied all at once from the A1 supply pipe.

Table 8 Example 4 Phenol, methanol and water (supplied molar ratio 1:8:
Example 1 was carried out in the same manner as in Example 1, except that 1.7) was supplied using a dispensing apparatus as described below.

The results are shown in Table 4.

1 59 550 2 29 8 29 0 As Comparative Example 4, the same procedure as in Example 4 was carried out except that the phenol was not supplied separately but instead was supplied all at once from the JI61 supply pipe.

Example 1 was carried out in the same manner as in Example 1, except that Table 4 (Table 1.7) was distributed and fed as shown below.

The results are shown in Table 6.

Supply pipe A Phenol supply rate Water + methanol J throat supply rate, ? ! -mo17'br m-moz/h
r1 82 62G2
16 σ8 16
C. In addition, as Comparative Example 5, the same procedure as Example 5 was carried out except that phenol was not distributed and supplied but was supplied all at once from the A1 supply pipe.

Table 6 Example 6 The same procedure as Example 1 was carried out except that the reaction temperature was 850° C. and ethanol was used instead of methanol. The result is the 6th
Shown in the table.

Table 6 Example 7 The same procedure as Example 1 was carried out except that m-cresol was used instead of phenol. The results are shown in Table 7.

As Comparative Example 7, A1 was prepared without distributing and supplying phenol.
The same procedure as in Example 7 was carried out except that the mixture was supplied all at once from the supply pipe.

7th Decline

[Brief explanation of drawings]

Figure 1 shows the residual ratio of pheno-J and 0-cresol and methanol when synthesizing 2゜6-xylenetool from pheno-1 and methano-1. It also shows the change in decomposition rate over time.

Claims (1)

[Claims] In a method for producing orthoalkylphenols by reacting a phenol having at least one hydrogen atom in the ortho position with an alcohol in the presence of a catalyst, the raw material phenol is introduced into a reaction gas stream passing through a catalyst bed. A method for producing orthoalkylphenols characterized by supplying them in portions