JPH0597766A - Production of ring aralkyl-disubstituted product of salicylic acid or its alkyl ester - Google Patents

Abstract

(57) [Summary] [Object] The present invention provides a method capable of economically producing a nuclear aralkyl di-substituted salicylic acid and an alkyl ester thereof by a simple reaction operation and separation / purification operation in good yield. It is a thing. [Constitution] In the present invention, the following A and B are A / B = 4/1
It is characterized in that the catalytic reaction is carried out at 00 to 27/100 (weight ratio). A: a mixture of an aliphatic hydroxy compound and an inorganic acid, wherein the aliphatic hydroxy compound / inorganic acid = 2/10
25 to 10 (weight ratio) B: A mixture of vinyl aromatic hydrocarbon and salicylic acid, wherein vinyl aromatic hydrocarbon / salicylic acid = 1.
Mixture of 6 / 1.0 to 2.2 / 1.0 (molar ratio)

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 a substituted aralkyl disubstituted salicylic acid or an alkyl ester thereof. A metal salt of a salicylic acid-substituted aralkyl di-substituted compound is used as an electron-accepting compound of a pressure-sensitive recording material using an electron-donating colorless dye and an electron-accepting compound. The present invention relates to an improvement in the method for producing such a substituted aralkyl disubstituted product or an alkyl ester thereof.

[0002]

2. Description of the Related Art Conventionally, as a method for producing a substituted aralkyl disubstituted product of salicylic acid, the following method has been proposed in which a salicylic acid or an alkyl salicylate is subjected to a nuclear aralkylation using a styrene compound in the presence of a catalyst. 1) A method in which an alkyl ester of salicylic acid is subjected to nuclear aralkylation and then hydrolyzed by using alkanesulfonic acid as a catalyst (Japanese Patent Publication No. 61-26772) 2) A method in which salicylic acid is subjected to nuclear aralkylation in the presence of an aromatic sulfonic acid (special feature) (Kaisho No. 62-84045) 3) A method in which an organic sulfonic acid or an inorganic acid is used as a catalyst in the presence of an aliphatic carboxylic acid to form a salicylic acid as a nuclear aralkyl (JP-A-2-91045).

However, the above-mentioned conventional method 1) is uneconomical because it uses a salicylic acid alkyl ester as a raw material and requires distilling the product under high temperature and reduced pressure. Further, in the above-mentioned conventional method 2), the reaction system becomes a nodular state, making the reaction operation difficult, and the amount of by-products such as mono-substituted products and styrene oligomers is large, and the separation and purification operation of the target nuclear aralkyl di-substituted product is complicated. And the yield is poor. In the conventional method of 3) above, the amount of by-produced salicylic acid in which the styrene compound double-ring is nucleus-substituted is large, and the operation for separating and purifying the desired nuclear aralkyldi-substituted product is complicated, and the yield is poor.

[0004]

The problem to be solved by the present invention is that the conventional method is too uneconomical, or the reaction system becomes agglomerated and the reaction operation is difficult, and the amount of by-product is small. In many cases, the operation of separating and purifying the desired nuclear aralkyl di-substituted product is complicated, and the yield thereof is poor.

[0005]

However, the present inventors have
As a result of earnest research on a method for producing a substituted aralkyl disubstituted product of salicylic acid, a mixture of an aliphatic hydroxy compound and an inorganic acid in a predetermined ratio and a mixture of a vinyl aromatic hydrocarbon and salicylic acid in a predetermined ratio are used, and a mixture thereof is used. It has been found that it is correct and suitable to react the above with a predetermined ratio.

That is, in the present invention, the following A and B are replaced by A
/ B = 4/100 to 27/100 (weight ratio). The present invention relates to a process for producing a substituted aralkyl disubstituted salicylic acid or an alkyl ester thereof. A: a mixture of an aliphatic hydroxy compound and an inorganic acid, wherein the aliphatic hydroxy compound / inorganic acid = 2/10
25/10 (weight ratio) B: a mixture of vinyl aromatic hydrocarbon and salicylic acid, wherein vinyl aromatic hydrocarbon / salicylic acid = 1.
Mixture of 6 / 1.0 to 2.2 / 1.0 (molar ratio)

In the present invention, the aliphatic hydroxy compound constituting A is 1) methanol, ethanol,
Aliphatic monohydric alcohols such as isopropanol, n-propanol, n-butanol and isobutanol 2)
Aliphatic dihydric alcohols such as ethylene glycol and propylene glycol, and alkoxyethanols such as 3) methyl cellosolve and ethyl cellosolve are mentioned, and among these, methanol and ethanol are particularly preferable.

The inorganic acid constituting A includes phosphoric acid, hydrochloric acid, sulfuric acid, nitric acid, perchloric acid, phosphorous acid, etc.
Of these, sulfuric acid and phosphoric acid are particularly preferable.

The content ratio of the aliphatic hydroxy compound constituting A and the inorganic acid is aliphatic hydroxy compound / inorganic acid = 2/10 to 25/10 (weight ratio), but 3/10
-10/10 (weight ratio) is preferable. The content ratio is 2 /
If it is less than 10 (weight ratio), the reaction system becomes a nodular state, making the reaction operation difficult and increasing the amount of by-products. On the other hand, when the content ratio is greater than 25/10 (weight ratio), the yield of the target nuclear aralkyl di-substituted product decreases.

Examples of the vinyl aromatic hydrocarbon which constitutes B include styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene and α-dimethylstyrene, and among these, styrene is particularly preferable.

The content ratio of vinyl aromatic hydrocarbon and salicylic acid constituting B is vinyl aromatic hydrocarbon / salicylic acid = 1.6 / 1.0 to 2.2 / 1.0 (molar ratio). It is preferably 1.8 / 1.0 to 2.0 / 1.0 (molar ratio). When the content ratio is less than 1.6 / 1.0 (molar ratio), the yield of the target nuclear aralkyl di-substituted product decreases. On the contrary, when the content ratio is larger than 2.2 / 1.0 (molar ratio), the amount of by-product increases.

In the present invention, the above A and B are A / B = 4
/ 100 to 27/100 (weight ratio), but especially 5/100 to 15/100 (weight ratio)
It is preferable to carry out a contact reaction with.

As a method for catalytically reacting A and B,
1) A method in which A and B are continuously brought into contact with each other at a predetermined ratio, 2) A small amount of B is mixed in advance with A, and then a predetermined amount of the remaining B is continuously or intermittently added. However, the present invention is not limited thereto. The contact reaction temperature of A and B is usually 50 to 120 ° C, preferably 60 to 90 ° C. In the present invention, A and B are catalytically reacted at a predetermined ratio, but the ratio of the aliphatic hydroxy compound contained in A and the salicylic acid contained in B is such that the aliphatic hydroxy compound / salicylic acid = 1/10 to 1/1 / It is preferable to carry out so as to be 20 (weight ratio). This is because the reaction operation becomes easier.

In the product obtained by applying the method of the present invention, salicylic acid obtained by esterification reaction of the aliphatic hydroxy compound contained in A with the nuclear aralkyl di-substituted product in addition to the salicylic acid substituted aralkyl di-substituted product. Alkyl esters of the aralkyl di-substituted form of Such an alkyl ester can be hydrolyzed as it is without being separated from the reaction system to give a corresponding aralkyl di-substituted product of salicylic acid. The nuclear aralkyl di-substituted salicylic acid thus obtained can be separated and purified from the reaction system by a known operation.

When the nuclear aralkyl di-substituted salicylic acid is a metal salt such as a zinc salt, an aqueous sodium hydroxide solution is added to the reaction system to neutralize the inorganic acid used in the catalytic reaction and the resulting nuclear aralkyl di-substituted compound. Further, after the saponified alkyl aralkyldi-substituted alkyl ester is saponified to form the sodium salt of the nuclear aralkyldi-substituted salicylic acid, an aqueous zinc chloride solution is added to reconstitute it to precipitate the zinc salt of the nuclear aralkyldi-substituted product. Therefore, this is filtered, washed with water, and dried to obtain a zinc salt of a salicylic acid-substituted aralkyldi-substituted product. If necessary, the zinc salt can be appropriately purified.

[0016]

【Example】

-Test Category 1 (Production of nuclear aralkyl di-substituted salicylic acid) -Example 1 Mixture (A-1) consisting of 1.5 kg of methanol and 2.5 kg of 97% sulfuric acid, and 33.2 kg of styrene and 22.6 kg of salicylic acid. And a mixture (B-1) consisting of
A-1 / B-1 = 7/1 by pump while keeping at ℃
While injecting into a continuous reactor (Kurimoto Iron Works Co., Ltd., S-1 type KRC kneader) so as to be 00 (weight ratio),
The contact reaction was continuously carried out under the condition of 5 ° C. × 120 rpm.
The discharge rate was set to 2.9 kg / hour by selecting the paddle pattern, and the discharged reaction product was stirred as it was in an aging kettle at 65 ° C. for about 20 hours, and the salicylic acid nuclear aralkyl di-substituted product and its alkyl compound were stirred. A mixed solution containing an ester was obtained.

Example 2 A mixture of 1.5 kg of ethanol and 2.3 kg of 97% sulfuric acid (A-2), and a mixture of 31.9 kg of α-methylstyrene and 22.6 kg of salicylic acid (B-2). ) Is maintained at 70 ° C, and pumped A-2 / B-
While injecting into a continuous reactor (the same as in Example 1) such that 2 = 7/100 (weight ratio), 75 ° C. × 1
The contact reaction was continuously carried out under the condition of 50 rpm. The discharge rate is set to 2.5 kg / hour by selecting the paddle pattern, and the discharged reaction product remains in the aging kettle until the discharge is completed.
The mixture was stirred at 5 ° C. for about 23 hours to obtain a mixed solution containing a salicylic acid nuclear aralkyl di-substituted product and an alkyl ester thereof.

Examples 3 to 5 and Comparative Examples 1 and 2 In the same manner as in Example 1, Examples 3 to 5 and Comparative Examples 1 and 2 were carried out. The contents of Examples 1 to 5 and Comparative Examples 1 and 2 are summarized in Table 1.

Comparative Example 3 8.5 g of methanol, 1.7 g of 97% sulfuric acid and 276 g of salicylic acid were added to the flask and heated to 70 ° C. It could not be stirred due to lack of fluidity. When the temperature was maintained at 70 ° C. and 405 g of styrene was added dropwise over 3 hours, stirring became possible at the end of the dropwise addition of the entire amount of styrene. After the dripping of the whole amount of styrene was completed, the reaction was further continued for 1 hour to obtain a mixed solution containing a salicylic acid nuclear aralkyl di-substituted product and an alkyl ester thereof.

Comparative Example 4 152 g of methyl salicylate and 20 g of methanesulfonic acid
Was charged into a flask, and 208 g of styrene was added to 1 at 65 ° C.
It was added dropwise over 4 hours. After the completion of dropping styrene, the mixture was further reacted for 1 hour to obtain a mixed solution containing a nucleus aralkyl di-substituted salicylic acid and an alkyl ester thereof.

Comparative Example 5 138 g of salicylic acid, 66 g of acetic acid and 33 g of methanesulfonic acid were added to a flask and heated to 110 ° C. Then, 208 g of styrene was added dropwise at this temperature over 4 hours.
After the completion of dropping styrene, the mixture was further reacted for 1 hour to obtain a mixed solution containing a nucleus aralkyl di-substituted salicylic acid and an alkyl ester thereof. The contents of Comparative Examples 3 to 5 are summarized in Table 2.

Test Category 2 (Measurement of Substituted Nuclear Aralkyldiones, etc. in Mixture) To the mixture obtained in Test Category 1 was added an aqueous sodium hydroxide solution for saponification and decomposition, and then equivalent to 0.1 mol of salicylic acid. Was collected, and 20 ml of n-hexane was added thereto to carry out an extraction operation to separate the n-hexane layer. This was concentrated and the weight of the vinyl aromatic hydrocarbon oligomer was measured. It was confirmed by IR absorption spectrum and GPC analysis that these were oligomers.

The aqueous layer remaining after separating the n-hexane layer was acidified with hydrochloric acid, the oily substance was separated, and the oily substance was vacuum dried at 100 ° C./1 mmHg to obtain a sample for analysis. did. This sample was collected by preparative GPC (gel permeation chromatography: column TOSOH TSK-G).
Each fraction was separated with EL, solvent THF, flow rate 1.2 ml / min). The structure of each fraction was confirmed by nuclear magnetic resonance spectroscopy, and the amounts of mono-, di- and poly-substituted products and unreacted salicylic acid were calculated by the GPC area method. The yield was calculated from the calculated value of the di-substituted product with respect to the theoretical yield value based on the salicylic acid used. The results are shown in Table 3.

Here, the mono-substituted product has one aralkyl group substituted in the benzene nucleus, the di-substituted product has two aralkyl groups substituted in the benzene nucleus, and the poly-substituted product has two vinyl aromatic hydrocarbons. It is one in which one or more benzene nuclei are substituted with at least one oligomeric vinyl aromatic hydrocarbon polymerized in a molar amount.

[0025]

[Table 1]

[0026]

[Table 2]

[0027]

[Table 3]

[0028]

As is apparent from the above, according to the present invention described above, it is possible to economically produce a nuclear aralkyl di-substituted salicylic acid and its alkyl ester by a simple reaction operation and separation / purification operation in good yield. There is an effect that can be.

Claims (1)

[Claims] 1. The following A and B are A / B = 4/100
A method for producing a substituted aralkyl di-substituted salicylic acid or an alkyl ester thereof, which is characterized by carrying out a catalytic reaction at 27 to 100 (weight ratio). A: a mixture of an aliphatic hydroxy compound and an inorganic acid, wherein the aliphatic hydroxy compound / inorganic acid = 2/10
25/10 (weight ratio) B: a mixture of vinyl aromatic hydrocarbon and salicylic acid, wherein vinyl aromatic hydrocarbon / salicylic acid = 1.
Mixture of 6 / 1.0 to 2.2 / 1.0 (molar ratio)