JPS60139636A - Process for producing thymol - Google Patents

Abstract

PURPOSE:To produce a thymol compound composed mainly of p- and o-thymol, economically in an industrial scale, by heating isopropyl-m-tolyl ether or a composition containing the same in the presence of a catalyst comprising a solid phosphoric acid. CONSTITUTION:Isopropyl-m-tolyl ether or a composition containing the same, e.g. the reaction product of m-cresol with propylene in the presence of a solid phosphoric acid catalyst, is heated in the presence of a solid phosphoric acid catalyst to obtain thymol compound composed mainly of p-thymol and o-thymol useful as an antiseptic, disinfectant, cosmetic, etc. at an o/p ratio of <=3/1, in high yield. Since the production ratio of m-thymol is low by this process, the objective compound can be separated and purified easily. The process is economical because the catalyst used in the reaction of m-cresol with propylene can be used as it is in the subsequent reaction, and the catalyst can be used repeatedly.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a method for producing thymols having a 4' form of p-thymol and 0-thymol from a substance containing isoprobyl-m-l-lylether or isoprobyl-m-tolyl ether. It is something.

O-thymol and p-thymol are used as preservatives, bactericidal agents, chemical products, etc. Among these, p-thymol in particular has stronger bactericidal activity than 0-thymol, phenol, cresol, etc. 1. It has excellent characteristics of low jfj and odor. .

However, as a method for producing thymol, conventionally m
- Several proposals have been made regarding the method of agitating cresol and propylene under the influence of a catalyst. e-3
0531: The publication describes a method using metal sulfate/γ-alumina as a catalyst, and Japanese Patent Publication No. 53-24408 describes a method using metal cerium as a catalyst.

However, these all relate to methods for selectively producing only O-thymol, and there are also methods for producing O-thymol and p-thymol simultaneously or methods for producing p-thymol. There's no measuring tape.

On the other hand, German Published Patent Application No. 2,139.822 discloses that m-cresol and propylene are mixed with ZnBrz-
A method has been described in which 0-thymol and p-thymol are obtained simultaneously in the presence of HBt4zO. There is a disadvantage that it is uneconomical because there is a large amount of raw 1- and it is difficult to recover and reuse the used catalyst.

Furthermore, as a method for simultaneously fjfing 0-thymol and p-thymol, a method in which m-cresol and isopropyl alcohol are reacted in the presence of phosphoric acid is also known, but in this method, multijI! of phosphoric acid is required;
Since the phosphoric acid is diluted by the produced water, it is difficult to recover the phosphoric acid, there are also problems in processing the waste acid, and inpropyl alcohol is relatively expensive as a raw material. However, it still has the disadvantage of being uneconomical.

By the way, the present inventor has discovered a method of reacting m-cresol and propylene in the presence of a solid phosphoric acid catalyst as a method for simultaneously obtaining 0-thymol and p-thymol. and 0-thymol can be obtained in good yield, and the production ratio of 0-thymol to p-thymol is 3/l or less, and m-thymol is produced as a by-product! Although we succeeded in reducing -, O-thymol and p
-In addition to thymol, a considerable amount of isopropyl-m-tolyl ether is inevitably produced as a by-product, and the yield of 0-thymol and p-thymol cannot be improved by more than 1° below a certain limit. Ta.

The present invention was discovered as a result of intensive research aimed at industrially advantageously producing thymols, particularly thymols that combine p-thymol and 〇-thymol. The gist is that when heating isopropyl-m-tolyl ether or isopropyl-m-tolyl ether-containing material in the presence of a catalyst to obtain a mol compound containing 1: p-thymol and O-thymol, 4. Using a solid phosphoric acid catalyst as the catalyst. It is in the method for producing thymol compounds, which are labeled as ¥.

By the method of the present invention, the isopropyl group of isopropyl-ml-lylether is rearranged to obtain p-thymol and O-thymol in good yields, and the production ratio of O-thymol and p-thymol at that time. becomes 3, /l or F゛.

In particular, when a reaction product obtained by reacting m-cresol and propylene in the presence of a phosphoric acid catalyst is used as the isopropyl-m-tolyl ether-containing material, isopropyl-m-)lyl ether in one reactant is p-thymol. and O-thymol, and the production of m-thymol 11'' is small.

The proportion of p-thymol and 0-thymol can be further increased. Moreover, since the production ratio of no-thymol to p-thymol is 3/l or less, the production rate of p-thymol relative to zero-thymol is significantly faster than in the conventional method.

Since 124 P-thymol and O-thymol have different boiling points, separation of these phases 1j is easy.

In addition, since the difference in boiling point is small, the formation of m-thymol, which is difficult to separate from p-thymol, is small, and therefore the target p-thymol can be easily separated and purified.

t3t Since the catalyst used in the reaction of m-cresol and propylene can be subsequently used in the heating reaction of isopropyl-m-)lyl ether, it is more advantageous in terms of production 1'.

An excellent effect can be obtained.

Furthermore, in the method of the present invention, the used solid phosphoric acid catalyst can be recovered and used repeatedly, which is also economically advantageous.

In the present invention, a solid phosphoric acid catalyst is present as a catalyst when isopropyl-m-)lyl ether is heated, but such a solid phosphoric acid catalyst is prepared by a conventional immersion method. - For example, after soaking the carrier in a commercially available 85% aqueous solution of phosphoric acid for several hours,
Remove moisture from A at 0°C, dry, and heat to 100°C in air.
It can be obtained by heat treatment at 800"C, or preferably 200 to 500C, and then allowed to cool.

Various types of carriers such as silica-based, alumina-based, titania-based, and zirconia-based carriers are used as the carrier on which the 1-th phosphoric acid is supported. Among these, silica alumina, diatomaceous 11. Examples include silica and titania, and it is preferable to use one or more of these to support phosphoric acid. For these carriers, for example, in the case of silica-based alumina, a+
The weight ratio of zo3/5i02 is 0/100 to 30/70
, especially those in the range of 5/85 to 15/85, and in the case of diatomaceous materials, the weight ratio of Al403/5iOz is 10/90.
Below, especially those below 5/85, in the case of silica/titania, the weight ratio of TiO2/5iOz is 07100 to 40
/flO range is preferably used.

When using silica alone, the reaction rate tends to be slightly slow, but it can be used as a carrier in the same way.

Next, the amount of phosphoric acid supported on these carriers is PLOr
41! I calculation +) acid/JE! body no m jJ: ratio
Most preferably it is within the range of O/80 to 25/75. If the weight ratio of phosphoric acid/111 is smaller than 10/90, the production ratio of 0-thymol/p-thymol becomes too large and does not meet the intended purpose; Even if the ratio is increased to 25/75 or more, the catalytic effect cannot be improved beyond a certain limit, which is economically disadvantageous, and the catalyst surface becomes sticky due to the hygroscopicity of P and O5.

Handling becomes difficult.

The shape or particle size of the catalyst may be either powder or granule, but when considering the reaction rate and the operability of recovering the used catalyst, one prepared to a size of about 30 to 200 mesh is used. It is preferable.

The amount of the above-mentioned catalyst used in the heating reaction of isopropyl-m-tolyl ether varies depending on the type of carrier, the amount of phosphoric acid supported, etc.
It is usually selected from the range of 10 to 35% by weight, preferably 10 to 35% by weight.

Next, as the reaction conditions for the reaction "-", the heating temperature is 10
0 to 400°C, preferably 150 to 300°C, the system pressure may be normal pressure or pressurized, and in the case of pressurized, 2
0Kg/C- or less is sufficient, and the reaction time is 0.5-1
It is desirable to choose from a range of 5 hours. The atmosphere of the system is air or an inert gas, preferably an inert gas (eg nitrogen gas).

The starting material used in the present invention is isopropyl-
m-) Lylether may be used alone, or isopropyl-
It may also be a material containing m-tolyl ether.

A typical example of the latter isopropyl-m-)lyl ether-containing product is a reaction product obtained by reacting m-cresol and propylene in the presence of a catalyst, that is, p-thymol and 0-thymol are combined into one, In addition to these, there may be mentioned reactants containing unreacted m-cresol, isopropyl-m-tolyl ether, myic-thymol, etc. as by-products. In this reaction of m-cresol and propylene, isopropyl-m-t-lyl ether is produced at a relatively low reaction temperature range, so it is preferable to start with the reaction product obtained by reacting at 100 to 200°C. If used as a substance, the production ψ of 0-thymol and p-thymol can be increased while keeping the ratio of 0-thymol/p-thymol small, so 0-thymol and p-thymol can be easily separated from each other. This is a very convenient method for obtaining both at the same time and in good yield.

Note that the isopropyl-m-tolyl ether-containing material may be any material containing inpropyl-m-tolyl ether, and is not limited to the above representative examples.

In addition, in the reaction of m-cresol and propylene mentioned above, when a solid phosphoric acid catalyst is used as a catalyst,
After the propylene is removed from the thread after the reaction, the reactant can be heated using the catalyst as it is, and there is no need to add a freshly prepared solid phosphoric acid catalyst, which is advantageous in this process.

After the reaction, p-thymol and 0-thymol, which are the target products, are obtained by appropriately changing known separation and purification means such as filtration, distillation, recrystallization, and extraction.

By the way, the solid phosphoric acid catalyst used in the above reaction can be used repeatedly in the heating reaction of isopropyl-m-tolyl ether. In this case, the reaction rate tends to decrease as the number of repeated uses increases, but no deterioration in the selectivity of the reaction product is observed even when used repeatedly. A decrease in the reaction rate can be prevented by increasing the reaction temperature, using a new solid phosphoryl catalyst, etc.

Next, the method of the present invention will be further explained with reference to Examples.

In the following, the reaction products were analyzed by gas chromatography.

Example 1 Isopropyl-m-)yl ether and m-
50.0 g of a mixture of cresol and 7.5 g of a phosphoric acid/silica titania catalyst (particle size 80 to 150 mesh) shown in Table 1 as a solid phosphoric acid catalyst were charged, and the mixture was stirred at a temperature of 185°C in an air atmosphere. The reaction was allowed to proceed while stirring.

The results are shown in Table 1.

tB1 table Note 1 The unit of the reaction product is ton-IJ-%.

The generation ratio is the vehicle end ratio.

Note 2 Ij-m-TE is isopropyl-m-tolyl ether.

2.6-D-m-CR is 2,6-diitupropy-m-cresol. 4.6-D-m-CR is 4,6-diitupropy-m-cresofur.

From the results in Table 1, the starting material isopropyl-m-
A part of tolyl ether undergoes a disproportionation reaction.
It changes into cresol and diisopropyl-m-cresol, but useful 0-thymol and p-thymol are produced by rearrangement of the isopropyl group.
The ratio of p-thymol to 0-thymol is approximately 1.9, which indicates that the production ratio of p-thymol to 0-thymol is significantly larger than that of the conventional method, and that the amount of m-thymol as a by-product is extremely small.

Example 2 In an autoclave, 310 g of m-cresol and the phosphoric acid/silica titania catalyst shown in Table 2 as a solid phosphoric acid catalyst (with a particle size of 80 to 150 mesh) 10E1
．． 5 g was charged, and the reaction was allowed to proceed at a temperature of 150° C. for 1.08 hours while stirring in the presence of propylene. During the reaction, the reaction pressure is 12 to 18 Kg/cm"
Propylene was introduced sequentially to maintain the amount of water used to replenish the consumed amount.

Next, the entire amount of the reaction solution after filtering off the catalyst from this reaction product and 41.0 g of the freshly prepared solid phosphoric acid catalyst were placed in an autoclave, and heated to 250 ml in the presence of nitrogen gas.
The reaction was allowed to proceed at a temperature of 100° C. with stirring.

The results are shown in Table 2.

Table 2 Note 1 The unit of reaction product is %.

No. 1. The composition ratio is a weight ratio.

Note 2 IP-m-TE is isopropyl-m-tolyl ether.

2.6-D-m-CR is 2,6-diisopropyl-m-cresol.

4.13-D-m-CR is 4,6-diisopropyl-m-cresol.

Example 3 In an autoclave, 310 g of m-cresol and 77.8 g of a solid phosphoric acid catalyst (phosphoric acid/diatomite catalyst shown in Table 3 (80 to 150 mesh) were charged, and in the presence of propylene, While stirring, the mixture was incubated at a temperature of 150'0 for 6 hours. During the reaction,
Propylene was successively introduced to maintain the reaction pressure at 15 Kg/cm' to replenish the consumed amount.

Next, the contents of the Oi-crepe containing the catalyst were cooled, and the residual propylene was discharged from the system by D1, followed by stirring at a pressure of 10 Kg/cm'' and a temperature of 2500 C in the presence of nitrogen gas. Meanwhile, a heating reaction was carried out for rearrangement of isopropyl-m-tolyl ether contained in the above contents.

The results are shown in Table 3.

Table 3 Note 1 The unit of the reaction product is Ilf amount%.

The production ratio is a weight ratio.

Note 2 IP-m-TE is isopropyl-m-1 lylether.

2, El-D-m-CR is 2,6-diisopropyl-m-cresol.

4.6-D-m-CR is 4,6-diisopropyl-m-cresol.

From the results shown in Tables 2 and 3, the solid phosphoric acid catalyst used in the reaction between 1m-cresol and propylene is suitable for the rearrangement reaction of isopropyl-m-)lyl ether contained in the reaction product. Being able to do X, 0
- The production ratio of thymol and p-thymol is 3.0 or less, and the production ratio of p-thymol to 0-thymol is significantly higher than that of the conventional method, and the by-product m
-of Timor! It can be seen that 11 is extremely small.

Example 4 After completing all the reaction paths of Example 3, the solid phosphoric acid catalyst was recovered by filtration from the reaction product, and then the entire reaction of Example 3 was repeated using this first recovered catalyst, and the same procedure was carried out thereafter. The reaction using the recovered catalyst was repeated up to the fourth time, but the same product composition as in Example 3 was obtained, except that the reaction time became longer each time. This shows that the solid phosphoric acid catalyst used in the reaction can be used repeatedly in the next reaction.

Claims (1)

[Claims] 1. In obtaining thymols containing p-thymol and O-thymol as one body by heating isopropyl-m-tolyl ether or isopropyl-m-)lyl ether-containing material to 1F in the presence of a catalyst. , 74%j and 1. A method for producing thymols characterized by using a solid phosphorus-resistant catalyst. 2. As one substance containing isopropyl-ml-lyl ether, m-cresol and propylene were used as a solid phosphorus corrosion-resistant compound.
#+f, Claim 41, characterized in that it uses a reactant that is reacted with 71 and 11)! J'S1'
One person listed in J'l. 3. As an isopropyl-m-tolyl ether-containing material,
When m-cresol and propylene are reacted in the presence of a solid phosphoric acid catalyst and a reactant is used, the isopropyl-rn-tolyl ether-containing material is heated in the presence of a catalyst to form p-thymol. In obtaining thymol having the t-isomer with 0-thymol, as the catalyst, +i
111. The method according to claim 1, characterized in that a solid phosphoric acid catalyst identical to that used in the reaction of m-crenoyl and propylene described in ii. above is used. 4. Recovering the national phosphoric acid catalyst after the reaction and repeatedly using it in the heating reaction of -isopropyl-m-tolyl ether or isopropyl-m-tolyl ether-containing material. The method described in D1.