JPS5852980B2 - Method for producing 2-(nitroaryl)ethanols - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing 2-(troaryl)ethanols with good selectivity from nitroargylbenzenes and aldehydes.

(2-troaryl) ethanols are compounds useful as intermediate raw materials for polymeric substances, polymeric stabilizers, pharmaceuticals, fragrances, and the like.

Despite this, little research has been conducted on its production method; for example, for 2-trophenyl) ethanol, Chemica Acta 8ea
-ndinavica1 Vol. 21, p. 1961 (196
Only a few cases have been reported, such as in 2007).

All of the manufacturing methods involve reacting nitrotoluene and paraformaldehyde in the presence of sodium ethoxide.

However, this method has the disadvantage that the catalyst, sodium ethoxide, is easily decomposed even by moisture in the air, making its preparation and handling difficult.

Furthermore, when sodium ethoxide is used as a catalyst,
The fatal disadvantage is that undesirable side reactions proceed simultaneously and the yield and selectivity of the desired 2-trophenyl are low.

Therefore, it is extremely difficult to economically produce ethanols on an industrial scale using the conventionally known methods.

The present inventors have conducted intensive research on a method for economically producing 2-(troaryl)ethanols on an industrial scale by eliminating these drawbacks found in conventional production methods.
The method of the present invention has been achieved.

That is, the present invention is a method for producing 2-(triaryl)ethanols, which is characterized by reacting ortho- or para-nitroalkylbenzenes and aldehydes in the presence of an alkali metal salt of a phenol.

The ortho- or varanitroalkylbenzenes used in the method of the present invention are ortho- or varanitroalkylbenzenes having a primary alkyl group or a secondary alkyl group, and have the general formula (wherein R1 and R2 are hydrogen, alkyl X represents hydrogen, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, an alkoxy group, a hydroxyl group, a halogen, a nitro Indicates the group.

) is a compound represented by

More specifically, for example, 0-nitrotoluene, p
-Nitrotoluene, 0-nitroethylbenzene, p-nitroethylbenzene, 0-nitrocumene, p-nitrocumene, 2-nitro-m-xylene, 4-nitro-m-xylene, 2-nitro-p-xylene, 2-nitro-m-cymene , 4-nitro-m-cymene, 2-nitro-p-cymene, 4-nitro-m-diisopropylbenzene, 0
-Nitroisobutylbenzene, p-nitroisobutylbenzene, p-nitrocyclohexylbenzene, p-nitrodiphenylmethane, 2-nitro-m-cresol, 4
-nitro-m-cresol, 3-nitro-p-cresol, 4-chloro-0-nitrotoluene, 5-chloro-0
-nitrotoluene, 2-chloro-p-nitrotoluene,
Examples include 2,4-dinitrotoluene and 3-methoxy-p-nitrotoluene.

Among these ortho- or varanitroalkylbenzenes, it is preferable to apply the method of the present invention to ortho- or para-nitrotoluenes, and it is particularly preferable to apply the method to ortho- or para-nitrotoluenes.

Further, the aldehydes used in the method of the present invention are aliphatic aldehydes or aromatic aldehydes.

More specifically, formaldehyde polymers that can be easily decomposed to generate formaldehyde under reaction conditions such as formaldehyde or paraformaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, cyclohexylaldehyde, benzaldehyde, tolualdehyde, p -chlorobenzaldehyde, m-methoxybenzaldehyde and the like.

Among these aldehydes, particularly good results are obtained when formaldehyde or its polymer is used.

The amount of these aldehydes to be used is 0.05 to 5 times the mole of the nitroalkylbenzenes, preferably 0.05 to 5 times the mole of the nitroalkylbenzenes.
The range is 2 to 15 times the mole.

The process of the invention is carried out in the presence of an alkali metal salt of phenols.

Here, the alkali metal salts of phenols and phenols or phenols with substituents inert to the reaction, such as cresol, ethylphenol, flobylphenol, butylphenol, cyclohexylphenol, phenylphenol, halogenated phenol, nitrophenol, etc. Mention may be made of alkali metal salts such as phenol, such as lithium, sodium and potassium salts.

Similar alkali metal salts of dihydric phenols such as catechol, resorcinol, hydroquinone, and diphenolic compounds such as bisphenol A can also be used.

These alkali metal salts of phenols are those produced separately outside the system, and those made by adding phenols and basic compounds such as hydroxides and carbonates of these alkali metals to the system are also used. can do.

Further, one or more of these alkali metal salts of phenols may be used in combination.

Among these alkali metal phenols, it is preferable to use sodium salts and/or potassium salts.

The amount used is generally 0.1 to 50 moles, preferably 0.5 to 30 moles, based on the aldehyde.

In the method of the present invention, aprotic polar compounds such as sulfoxides, carboxylic acid amides, and phosphoric acid amides exhibit excellent solvent effects and significantly accelerate the reaction rate, so it is preferable to use these compounds as solvents. .

Examples of such solvents include dimethyl sulfoxide, dimethyl sulfone, sulfolane, dimethylformamide, diethylacetamide, dimethylacetamide,
Examples include N-methyl-2-pyrrolidone and hexamethylphosphoramide.

The amount of the solvent to be used is 0.1 to 20, preferably 0.5 to 10, by volume relative to the ortho or varanitroalkylbenzene.

The reaction is carried out at a temperature of O'C to 250C, preferably 20 to 200C, and at atmospheric pressure or above.

The reaction time is not particularly limited, but is generally 0.25 to 10 hours.

The produced 2-(troaryl)ethanols are separated and purified from the reaction mixture by common operations such as distillation and extraction.

** The steps of the present invention will be specifically explained below using examples.

In the Examples and Comparative Examples, the yield represents the mole φ based on the aldehydes used, and the selectivity represents the mole φ based on the reacted nitroalkylbenzenes.

Examples 1 to 4, Comparative Examples 1 to 3 0-Nitrotoluene 9.2 g (low millimoles), 80 g of paraformaldehyde 0.94 g (corresponding to 25 millimoles of formaldehyde), dimethyl sulfoxide 7,
A mixture of 8 ml and catalyst (described in Group 1) was stirred for 1 hour under the conditions shown in Table 1.

After neutralizing the reaction mixture with dilute hydrochloric acid, the product was analyzed by gas chromatography to determine the yield and selectivity of 2-(o-nitrophenyl)ethanol.

The results are shown in Table 1.

Examples 5-6, Comparative Example 4 A mixture of 9.2 g of 0-nitrotoluene, 0.94 g of 80% paraformaldehyde, 7.8 g of dimethylformamide and the catalyst shown in Table 2 (5.9 mmol) was
Stirred for 1 hour at 0.degree. C. and analyzed the product using the method of Example 1.

The results are shown in Table 2. Example 7 A reaction was carried out in the same manner as in Example 5 except that the catalyst amount was changed to 2.0 mmol and the reaction temperature was changed to 120°C, and 2-(o-nitrophenyl)ethanol was produced. It was obtained with a yield of 54% and a selectivity of 99%.

*The reaction was carried out in the same manner as in Example 2 except that the compound shown was used as a catalyst.

The results are shown in Table 3. Example 13 54m of phenol in 7.8TLl of dimethyl sulfoxide
9 (0,57 mmol) and caustic potash 32r119 (
0.57 mmol) was added and stirred at 60°C for 30 minutes.

After adding 9.2 g of 0-nitrotoluene and 0.94 g of 80% paraformaldehyde and stirring at 60°C for an additional hour, 2-(〇-nitrophenyl)ethanol was obtained with a yield of 62φ and a selectivity of 91φ. Ta.

Examples 14-15, Comparative Example 6 A mixture of 9.2 L of p-nitrotoluene, 0.94 g of 80% paraformaldehyde, 7.87711 g of dimethyl sulfoxide, and the catalyst shown in Table 4 (0.57 ml J mol) was heated to 60° C. for 1 hour. The mixture was heated and stirred.

After neutralizing the reaction mixture with dilute hydrochloric acid, the product was analyzed by gas chromatography.

The results are shown in Table 4. Example 16 6.9 g of 0-nitrotoluene, 3.2 g of benzaldehyde
When a mixture consisting of g, 7.0 ml of dimethyl sulfoxide and 0.1 (l) of potassium phenoxide was stirred at 90°C for 1 hour, 1-phenyl-2-(0-nitrophenyl)ethanol was obtained in a yield of 47%. The yield was 79%.

Example 17 2-nitro-p-xylene 10.1.91 80% paraformaldehyde 0.94 g, dimethyl sulfoxide 7.
When a mixture consisting of 0.8% and 0.089% potassium phenoxide was stirred at 90°C for 1 hour, 2-(o-nitro-p-methylphenyl)ethanol was produced in a yield of 59%.
A selectivity of 86% was obtained.

Claims (1)

[Scope of the Claims] 1. A method for producing 2-(nitroaryl)ethanols, which comprises reacting ortho- or para-nitroalkylbenzenes and aldehydes in the presence of an alkali metal salt of a phenol. 2. The method of claim 1, wherein the reaction is carried out in an aprotic polar solvent. 3. The method according to claim 1 or 2, wherein the alkali metal salt of phenol is used in an amount of 0.5 to 30 mol based on the aldehyde. 4. The method according to any one of claims 1 to 3, wherein a sodium salt and/or potassium salt of phenol is used as the alkali metal salt of phenol. 5. The method according to any one of claims 1 to 4, wherein ortho or para-nitrotoluenes are used as the ortho- or para-nitroalkylbenzenes. 6. The method according to any one of claims 1 to 5, wherein ortho or para-nitrotoluene is used as the ortho- or para-nitroalkylbenzene. 7. The method according to any one of claims 1 to 6, wherein formaldehyde or a formaldehyde polymer is used as the aldehyde. 8. The method according to any one of claims 1 to 7, wherein the reaction is carried out at a temperature of 20 to 200°C.