Method for producing 4-alkylresorcinol

Abstract

The present invention relates to a method for producing alkylresorcinol, specifically 4-alkylresorcinol, and more specifically, to a method for producing 4-alkylresorcinol, which enables the production of 4-alkylresorcinol to have high yield and high purity, and which is environmentally friendly.

Description

Technical Field

[0001] The present invention relates to alkylresorcinols, specifically to a method for manufacturing 4-alkylresorcinols. More specifically, it relates to a manufacturing method that can achieve a high yield, high purity, and environmental friendliness in the production of 4-alkylresorcinols. Background Art

[0002] So-called skin pigmentation generally refers to the state where melanin is produced and appears when the skin is exposed to ultraviolet rays. After the skin is irradiated with ultraviolet rays, keratinocytes in the epidermis secrete α-melanocyte stimulating hormone (α-MSH), which in turn stimulates melanocytes. Melanocytes stimulated by α-melanocyte stimulating hormone promote the expression of the tyrosinase gene, and tyrosinase oxidizes tyrosine, an amino acid, thereby initiating the melanin production process. The high-molecular-weight melanin formed in melanocytes migrates to keratinocytes. Over time, newly formed keratinocytes push the keratinocytes containing melanin upward to the stratum corneum, and ultimately the skin appears dark due to the melanin contained in the keratinocytes.

[0003] Whitening cosmetics refer to cosmetics that have the effect of inhibiting this process and making the skin white. Whitening cosmetics usually achieve the whitening effect by blocking the transmission of external stimuli to melanocytes, inhibiting the synthesis or activity of tyrosinase, an enzyme essential for melanin production, reducing the generated melanin, or promoting the excretion of melanin by rapidly removing cutin.

[0004] Among them, the method of blocking the initial stage of melanin production by inhibiting tyrosinase activity is generally considered the most powerful whitening mechanism. Whitening substances used to block the initial stage of melanin production include hydroquinone, kojic acid, arbutin, etc. However, traditional whitening substances have problems such as toxicity, skin irritation, and side effects in terms of stability, and the whitening effect is also minimal. Therefore, alternative substances need to be developed.

[0005] 4-alkylresorcinol, especially 4-n-butylresorcinol, which has been discovered as a new generation of whitening material, can simultaneously inhibit tyrosinase and tyrosinase active protein, thereby showing a unique whitening effect, with the advantages of safe use without side effects, high formability, and easy compounding with other raw materials.

[0006] However, in the traditional method for manufacturing 4-alkylresorcinol, due to the long reaction time, the production efficiency is low, and the purity and yield of the product are also low. Therefore, compared with traditional whitening substances, it does not have a competitive advantage in terms of price. In addition, solvents harmful to the human body such as toluene or methanol are used in the manufacturing process, so there is a problem of lack of environmental friendliness. Therefore, there is a need to develop a method for manufacturing 4-alkylresorcinol that can improve production efficiency and environmental friendliness. Summary of the Invention

[0007] The present invention is created to solve the above technical problems. The technical problem to be solved by the present invention is to significantly shorten the reaction time by irradiating microwaves for a chemical reaction, and provide a method for manufacturing 4-alkylresorcinol with high purity and high yield.

[0008] Another problem to be solved by the present invention is to provide a method for manufacturing 4-alkylresorcinol with environmental friendliness.

[0009] The object of the present invention is not limited to the above-described objects. Other objects and advantages of the present invention that are not mentioned can be understood from the following description, and can be more clearly understood through the embodiments of the present invention. In addition, it is obvious that the objects and advantages of the present invention can be achieved by the means and combinations shown in the claims.

[0010] To solve the above-mentioned technical problems, the present invention provides a method for manufacturing 4-alkylresorcinol. Preferably, it includes: S10 a step of performing an acylation reaction between resorcinol and an acyl halide having 3 to 8 carbon atoms to generate an intermediate; and S20 a step of reducing the carbonyl group of the intermediate. In the method for manufacturing 4-alkylresorcinol, at least one of the S10 and S20 steps is performed while irradiating microwaves.

[0011] According to an embodiment of the present invention, the microwaves are irradiated at an intensity of 0.1 W / ml to 15 W / mL, and preferably can be irradiated at an intensity of 0.5 W / ml to 6 W / ml.

[0012] According to an embodiment of the present invention, at least one of the S10 and S20 steps is performed without a solvent (solvent free).

[0013] According to an embodiment of the present invention, at least one of the S10 and S20 steps can be performed under zinc catalysis.

[0014] According to an embodiment of the present invention, the step S10 further includes a step of purifying the intermediate; the step of purifying the intermediate includes: S11 a step of extracting the intermediate using a first organic solvent and an aqueous sodium chloride solution; S12 a step of precipitating by-products from the extract obtained in the step S11 using a second organic solvent.

[0015] According to the manufacturing method of the present invention, the beneficial effects are that the manufacturing time of 4-alkylresorcinol can be significantly shortened, and the yield and purity of 4-alkylresorcinol can be improved.

[0016] According to the manufacturing method of the present invention, the beneficial effects are that during the manufacturing process, the use of mercury-based catalysts and solvents such as toluene is excluded, thereby providing an environmentally friendly manufacturing method for 4-alkylresorcinol.

[0017] In addition to the above effects, the specific effects of the present invention are described while describing the specific content required to implement the present invention below. Description of the Drawings

[0018] Figure 1 It is a reaction formula showing the chemical reactions of each step of the manufacturing method of 4-alkylresorcinol according to an embodiment of the present invention;

[0019] Figure 2a It is the chemical structural formula of 1-(2,4-dihydroxyphenyl)butan-1-one;

[0020] Figure 2b It is a diagram showing the product of the benzene ring acylation reaction in one step of the manufacturing method of 4-alkylresorcinol according to an embodiment of the present invention 1 H-NMR spectrum;

[0021] Figure 2c It is a diagram showing the LC-MS spectrum of the product of the benzene ring acylation reaction in one step of the manufacturing method of 4-alkylresorcinol according to an embodiment of the present invention;

[0022] Figure 3a It is the chemical structural formula of 4-alkylresorcinol;

[0023] Figure 3b It is a diagram showing the product of the carbonyl reduction reaction in the second step of the manufacturing method of 4-alkylresorcinol according to an embodiment of the present invention 1 H-NMR spectrum;

[0024] Figure 3c It is a diagram showing the LC-MS spectrum of the product of the carbonyl reduction reaction in the second step of the manufacturing method of 4-alkylresorcinol according to an embodiment of the present invention. Detailed Description of the Invention

[0025] The principle of the preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. However, the figures shown below and the following description are related to the preferred implementation methods among various methods of the present invention, aiming to effectively illustrate the features of the present invention. The present invention is not limited to the following figures and descriptions.

[0026] In addition, terms such as first, second, etc. can be used to describe various components, but these terms are only used to distinguish one component from other components. For example, the first component can be named the second component, and similarly, the second component can be named the first component.

[0027] The singular form also includes the plural form in the sentence without special indication. Terms such as "including" or "having" used in this specification are used to specify the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and do not preclude the existence or additional possibility of one or more other features or numbers, steps, actions, components, parts, or combinations thereof in advance.

[0028] In this specification, the so-called excess means 1 equivalent or more.

[0029] Without special description, including technical or scientific terms, all terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field of the present invention. The meaning of the terms defined in the commonly used dictionary is consistent with the meaning in the technical text. As long as it is not clearly defined in this specification, it should not be interpreted in an abnormal or excessive form.

[0030] As described above, the conventional manufacturing method of 4-alkylresorcinol, which has attracted attention as a next-generation whitening substance, has problems such as a long reaction time and the extensive use of catalysts and solvents harmful to the human body during the manufacturing process. As a result of the efforts made by the present inventors to solve the above-mentioned multiple problems, it has been found that the use of microwave can shorten the manufacturing time of 4-alkylresorcinol, significantly improve production efficiency, increase the yield and purity, and thus greatly reduce the manufacturing cost.

[0031] The present invention includes step S10 of subjecting resorcinol and acyl halide having 3 to 8 carbon atoms to an acylation reaction to generate an intermediate; and step S20 of reducing the carbonyl group of the intermediate; in steps S10 and S20, at least one step is carried out while irradiating microwave, and a manufacturing method of 4-alkylresorcinol is provided.

[0032] Figure 1 It is a chemical reaction formula showing each step of the 4-alkylresorcinol manufacturing reaction of an embodiment of the present invention.

[0033] In the conventional method for manufacturing 4-alkylresorcinol compounds, a method of reacting a resorcinol compound with an alkyl halide is used. The problem with this reaction is that due to the low position selectivity of the benzene ring, unnecessary by-products such as 2-alkylresorcinol and 4,6-dialkylresorcinol are produced. The present invention obtains an aromatic ketone having the same structure as the following Chemical Formula 1 from the product (intermediate) of the reaction in Step S10, reduces it, and has a high position selectivity for the benzene ring, thereby significantly improving the yield.

[0034] [Chemical Formula 1]

[0035]

[0036] In the said Chemical Formula 1, R is an alkyl group of C2 to C7.

[0037] In addition, even when following the reaction of introducing an acyl group into the benzene ring of resorcinol using an acyl halide first, in the conventional manufacturing method, there are also problems such as using substances harmful to the human body and causing environmental pollution, such as zinc chloride (ZnCl2), a Lewis acid catalyst, and an organic solvent such as toluene, and the reaction time is also long.

[0038] According to the manufacturing method of the present invention, microwave can be irradiated and an acylation reaction can be carried out, thereby eliminating the use of catalysts and solvents that cause environmental pollution.

[0039] The following specifically describes each step.

[0040] In the present invention, the Step S10 is a step of causing resorcinol and an acyl halide to undergo an acylation reaction under microwave irradiation to generate an intermediate having the structure of the following Chemical Formula 1.

[0041] [Chemical Formula 1]

[0042]

[0043] In the said Chemical Formula 1, R is an alkyl group of C2 to C7.

[0044] According to the present invention, through Step S10, the position selectivity of the acylation reaction of resorcinol can be improved, the generation of by-products with acyl groups bonded at different positions, such as 2-acylresorcinol and 4,6-diacylresorcinol, can be reduced, thereby increasing the yield and saving the manufacturing cost. Specifically, the acylation reaction can follow the mechanism of the Friedel-Crafts acylation reaction.

[0045] In a preferred embodiment of the present invention, the acylation reaction in step S10 can be carried out under the catalysis of zinc (Zn). Preferably, the zinc catalyst can be added in powder form in an amount of 0.8 to 1.2 equivalents relative to the resorcinol. Preferably, it is 0.5 to 1.5 equivalents, and most preferably, it is 0.8 to 1.2 equivalents.

[0046] In a preferred embodiment of the present invention, step S10 can be carried out by a non-solvent reaction without using a solvent. Further, step S10 of the present invention is carried out by a non-solvent reaction while irradiating with microwaves, so it is environmentally friendly and a high-yield intermediate can be obtained.

[0047] In the present invention, the non-solvent reaction without using a solvent means not using a solvent that can dissolve the reactants.

[0048] In a preferred embodiment of the present invention, the acyl halide can be butyryl chloride, pentanoyl chloride, and 3-methylpropionyl chloride. Most preferably, butyryl chloride can be used.

[0049] In the present invention, since the acylation reaction is carried out under microwave irradiation, an acylation reaction can be caused without using a strong Lewis acid catalyst such as zinc chloride (ZnCl2) or aluminum chloride (AlCl3), and the reaction time can be significantly shortened.

[0050] Microwave is a kind of electromagnetic wave, which refers to an electromagnetic wave with a wavelength longer than that of infrared rays, usually having a wavelength (λ) of more than 1 mm. Specifically, microwaves with a wavelength of about 1 mm to 10 cm can be irradiated.

[0051] In a preferred embodiment of the present invention, there is a correlation between the microwave and the volume of the irradiated reactant. Hereinafter, the volume of the reactant will be referred to as the unit volume.

[0052] In an embodiment of the present invention, the microwave intensity relative to the unit volume is 0.1 W / ml to 15 W / ml. More preferably, it is irradiated with an intensity of 0.5 W / ml to 6 W / ml. In addition, the reaction temperature is preferably 45°C to 140°C, and more preferably 55°C to 130°C.

[0053] In the method for manufacturing 4-alkylresorcinol of the present invention, a higher synthesis efficiency can be obtained compared with the case of microwave irradiation, and the object of the present invention can still be achieved without excessive use or without using organic solvents, Lewis acids, etc. that cause environmental pollution.

[0054] When the microwave intensity is less than 0.1 W / ml per unit volume or the reaction temperature is less than 45 °C, the improvement in production efficiency may not be significant due to the reduced reaction rate, and the internal temperature of the reaction substances is uneven, which may lead to a decrease in the yield.

[0055] When the microwave intensity per unit volume exceeds 15 W / ml or the reaction temperature exceeds 75 °C, the side reaction may be promoted and the reaction yield may be reduced.

[0056] In addition, the S10 step can be carried out for 3 minutes to 30 minutes. This is significantly shorter compared to the conventional method for manufacturing 4-acylresorcinol that requires a total of 4 to 10 hours.

[0057] According to the manufacturing method of the present invention, in the S10 step, by irradiating microwaves, the reaction can be carried out without using a solvent, thereby obtaining an intermediate with environmental friendliness and high yield.

[0058] In the present invention, the S10 step may further include a step of purifying the generated intermediate.

[0059] In one embodiment of the present invention, the purification step may include: S11 a step of extracting the intermediate using a first organic solvent and an aqueous sodium chloride solution; and S12 a step of precipitating impurities from the extract obtained in the S11 step using a second organic solvent.

[0060] The first organic solvent may be a non-polar solvent such as ether, chloroform, benzene, hexane or dichloromethane, or a mixed solvent thereof. Preferably, it is dichloromethane. A saturated chloride of an additional solvent, i.e., a mixed solvent, can be used as the extraction solvent for extraction. Preferably, it is an aqueous sodium chloride solution.

[0061] Here, the aqueous sodium chloride solution may be a saturated aqueous sodium chloride solution (Brine).

[0062] In one embodiment of the present invention, the mixing weight ratio of the first organic solvent to the aqueous sodium chloride solution in the extraction solvent may be 1:0.1 to 1:10, preferably 1:0.5 to 1:3, and most preferably 1:0.8 to 1:1.2.

[0063] The intermediate extracted in the S11 step has its purity improved by precipitating impurities using a second organic solvent in the S12 step. The second organic solvent is preferably a non-polar solvent such as ether, chloroform, benzene, hexane or dichloromethane, or a mixed solvent thereof. Preferably, the second organic solvent may be hexane.

[0064] The step S20 is a step of performing a reaction to obtain a 4-alkylresorcinol compound by reducing the carbonyl group in the intermediate, i.e., 4-acylresorcinol compound, generated in the step S10.

[0065] In one embodiment of the present invention, the reaction of reducing the carbonyl group of the intermediate is also carried out by irradiating microwaves, so that a high-yield reaction can be carried out even without using a harmful mercury-based catalyst.

[0066] The reduction reaction in the step S20 may preferably follow the mechanism of the Wolff-Kishner reduction reaction or the Clemmensen reduction reaction. Preferably, it can be carried out following the Clemmensen reduction mechanism.

[0067] In a preferred embodiment of the present invention, the step S20 can also be carried out by a non-solvent reaction, i.e., without using a solvent.

[0068] In a preferred embodiment of the present invention, a non-mercury-based catalyst can be used in the step S20, and the non-mercury catalyst can be zinc (Zn). Specifically, the zinc can be provided in powder form and can be provided in excess compared to the intermediate. Preferably, the non-mercury-based catalyst can be provided to the reaction in an amount of 12 equivalents to 15 equivalents compared to the intermediate. Different from the Clemmensen reduction reaction that usually uses a mercury alloy catalyst, the present invention can simply use a zinc catalyst, thereby improving the environmental friendliness of the process.

[0069] In a preferred embodiment of the present invention, in the above step S20, microwaves are irradiated at an intensity of 0.1 W / ml to 15 W / ml, more preferably 0.5 W / ml to 6 W / ml, and most preferably 1 W / ml to 3 W / ml per unit volume, and the reduction reaction is carried out.

[0070] When the microwave intensity per unit volume is less than 0.1 W / ml, the reduction reaction may not be carried out only by the zinc catalyst. When it exceeds 15 W / ml, carbonization may occur due to the too rapid rise in the internal temperature of the reactants.

[0071] The reduction reaction in the step S20 is preferably carried out at a temperature of 70°C to 110°C. When the reaction temperature is lower than 70°C, the reaction rate may decrease, resulting in a decrease in the yield of the 4-alkenylresorcinol production reaction.

[0072] In addition, in a preferred embodiment of the present invention, the reduction reaction in step S20 can use one or more mixed solvents selected from the group consisting of aliphatic alcohols having 2 to 5 carbon atoms and water. Preferably, ethanol can be used as the solvent. In a preferred embodiment of the present invention, the reduction reaction in S20 does not use a mercury-based catalyst, but uses a solvent formed by alcohol and water instead of an environmentally harmful organic solvent, thereby minimizing harm to the human body and environmental pollution to the greatest extent.

[0073] The compound generated by the reaction is 4-alkylresorcinol represented by Chemical Formula 2 below.

[0074] [Chemical Formula 2]

[0075]

[0076] In Chemical Formula 2, R' is an alkyl group having 3 to 8 carbon atoms.

[0077] In the conventional method for manufacturing 4-alkylresorcinol, when using the Clemmensen reduction reaction, the reduction reaction is carried out at room temperature for more than 10 hours. Therefore, there is a problem that the reaction time is long and the production efficiency is very low.

[0078] According to the present invention, when irradiating microwaves during the S20 Clemmensen reduction reaction and carrying out the reduction reaction simultaneously, the reaction time can be significantly shortened, and 4-alkylresorcinol can be obtained in a high yield.

[0079] Step S20 includes a step of purifying 4-alkylresorcinol generated by the reduction reaction. Specifically, the purification step may include:

[0080] S21 A step of extracting 4-alkylresorcinol using a first organic solvent and an aqueous sodium chloride solution;

[0081] S22 A step of precipitating impurities from 4-alkylresorcinol extracted using a second organic solvent.

[0082] Preferably, the first organic solvent may be a non-polar solvent such as ether, chloroform, benzene, hexane, or dichloromethane, or a mixed solvent thereof. However, the type of the first organic solvent is not limited thereto.

[0083] In an embodiment of the present invention, in step S21, most preferably, a mixed solvent of dichloromethane and an aqueous sodium chloride solution is used as the extraction solvent.

[0084] In an embodiment of the present invention, in the extraction solvent, the mixing weight ratio of the first organic solvent and the aqueous sodium chloride solution may be 1:0.1 to 1:5, preferably 1:0.5 to 1:3, and most preferably 1:0.8 to 1:1.2.

[0085] In addition, the 4-butylresorcinol extracted in the step S21 can precipitate impurities using a second organic solvent in the step S22, and the purity can be improved during this process. The second organic solvent is preferably a non-polar solvent such as ether, chloroform, benzene, hexane, or dichloromethane, or a mixed solvent thereof. Preferably, hexane can be used as the second organic solvent.

[0086] As described above, by removing the precipitated impurities in the step S22, the 4-alkylresorcinol generated in the step S20 can be purified.

[0087] Preferably, the first organic solvent can be a non-polar solvent such as ether, chloroform, benzene, hexane, or dichloromethane, or a mixed solvent thereof.

[0088] In one embodiment of the present invention, in the purification step, most preferably, a mixed solvent of dichloromethane and an aqueous sodium chloride solution is used as the extraction solvent.

[0089] In one embodiment of the present invention, in the extraction solvent, the mixed weight ratio of the first organic solvent to the aqueous sodium chloride solution can be 1:0.1 to 1:5, preferably 1:0.5 to 1:3, and most preferably 1:0.8 to 1:1.2.

[0090] In the conventional method for manufacturing 4-alkylresorcinol, column chromatography purification is used to purify 4-alkylresorcinol. However, the purification method using column chromatography is very difficult, the purification time is long, and the production efficiency is very low. There are also problems in terms of product purity due to chemical residue problems.

[0091] According to the present invention, the step S21 of extracting 4-alkylresorcinol using a first organic solvent and an aqueous sodium chloride solution is carried out; the step S22 of using a second organic solvent to precipitate impurities from the 4-alkylresorcinol and obtaining 4-butylresorcinol with impurities removed through recrystallization is carried out. Therefore, compared with the conventional column chromatography purification method, it is simpler, the purification time is significantly reduced, and 4-butylresorcinol with high purity can be obtained.

[0092] The present invention will be further described in detail below through examples and experimental examples. These examples and experimental examples are only used to specifically illustrate the present invention, and the scope of the present invention is not limited to these examples and experimental examples.

[0093] Synthesis Example 1

[0094] [Example 1]

[0095] Add 1.1613 g of zinc powder, 1 g of resorcinol, and 1.13 ml of butyryl chloride to a microwave reaction vessel. Then, irradiate with microwaves at an intensity of 6 W / ml for about 5 minutes while stirring at a temperature of 65 °C to carry out the reaction.

[0096] Then, after removing the reaction by-products with a mixed solvent of an aqueous sodium chloride solution and dichloromethane in a 1:1 weight ratio, 1-(2,4-dihydroxyphenyl)butan-1-one of Formula 3 is obtained.

[0097] [Formula 3]

[0098]

[0099] The following are the nuclear magnetic resonance data of [Formula 3] 1-(2,4-dihydroxyphenyl)butan-1-one. The nuclear magnetic resonance (NMR) and mass spectroscopy data are as Figures 2b to 2c shown.

[0100] 1 H-NMR (400 MHz, DMSO-d6)

[0101] δ 8.25 - 8.23 (d, 1H), 8.08 (t, 1H), 4.19 - 4.14 (m, 1H), 4.01 - 4.03 (m, 2H), 3.08 - 3.07 (m, 2H), 2.64 - 2.61 (t, 2H), 2.37 - 2.33 (t, 2H), 2.13 - 2.09 (t, 1H), 2.08 (s, 3H) 1.74 - 1.67 (m, 1H), 1.65 - 1.55 (m, 1H), 1.53 - 1.47 (m, 4H), 1.28 - 1.22 (m, 16H), 1.18 - 1.14 (t, 3H), 0.86 - 0.82 (t, 3H).

[0102] [Comparative Example 1]

[0103] 1-(2,4-Dihydroxyphenyl)butan-1-one was prepared in the same manner as in Example 1, but after placing the sample in a glass reaction vessel, microwave irradiation was not carried out, and the reaction was carried out at a temperature of 65 °C for five minutes.

[0104] [Comparative Example 2]

[0105] 1-(2,4-dihydroxyphenyl)butan-1-one was prepared in the same manner as in Example 1, but when purifying the intermediate, instead of using a mixed solvent, an aqueous sodium chloride solution was used to remove impurities, and then the intermediate, 1-(2,4-dihydroxyphenyl)butan-1-one, was obtained.

[0106] [Comparative Example 3]

[0107] 1-(2,4-dihydroxyphenyl)butan-1-one was prepared in the same manner as in Example 1, but when purifying the intermediate, instead of using a mixed solvent, dichloromethane was used to remove impurities, and then the intermediate, 1-(2,4-dihydroxyphenyl)butan-1-one, was obtained.

[0108] [Synthesis Example 2]

[0109] [Example 2]

[0110] 4.97 g of zinc powder was added to a microwave reaction vessel, and 1 g of the intermediate 1-(2,4-dihydroxyphenyl)butan-1-one prepared in Example 1 and 2 ml of ethanol were added. Then, concentrated hydrochloric acid was added at a rate of 0.25 mL / min for 40 minutes using an addition funnel.

[0111] Then, the reaction was carried out by irradiating microwaves at a power of 6 W / ml at 80 °C for about 20 minutes. After the reaction, 4-butylresorcinol was extracted using a first mixed solvent obtained by mixing dichloromethane and an aqueous sodium chloride solution at a weight ratio of 1:1, and impurities were removed by precipitation from the extracted 4-butylresorcinol using a second mixed solvent obtained by mixing dichloromethane and hexane at a weight ratio of 1:50. Finally, the separated 4-butylresorcinol was recrystallized by precipitation in ice water for 2 hours to obtain high-purity 4-butylresorcinol having the structure of Chemical Formula 4 below.

[0112] [Chemical Formula 4]

[0113]

[0114] The following are the 1 1H-NMR data of 4-butylresorcinol. The nuclear magnetic resonance (NMR) and mass spectroscopy data are shown in Figure 3.

[0115] 1 H-NMR (400 MHz, DMSO-d6)

[0116] δ 8.25 - 8.23 (d, 1H), 8.08 (t, 1H), 4.19 - 4.14 (m, 1H), 4.01 - 4.03 (m, 2H), 3.08 - 3.07 (m, 2H), 2.64 - 2.61 (t, 2H), 2.37 - 2.33 (t, 2H), 2.13 - 2.09 (t, 1H), 2.08 (s, 3H), 1.74 - 1.67 (m, 1H), 1.65 - 1.55 (m, 1H), 1.53 - 1.47 (m, 4H), 1.28 - 1.22 (m, 16H), 1.18 - 1.14 (t, 3H), 0.86 - 0.82 (t, 3H).

[0117] [Comparative Example 4]

[0118] 4-Butylresorcinol was produced in the same manner as in Example 2, but without irradiating microwaves, and the reduction reaction was carried out at a temperature of 80 °C for 20 minutes.

[0119] [Comparative Example 5]

[0120] 4-Butylresorcinol was produced in the same manner as in Example 2, but the step of extracting 4-butylresorcinol with the first mixed solvent was omitted.

[0121] [Comparative Example 6]

[0122] 4-Butylresorcinol was produced in the same manner as in Example 2, but the step of precipitating impurities with the second mixed solvent composed of dichloromethane and hexane in the 4-butylresorcinol extracted with the first mixed solvent was omitted.

[0123] Experimental Example 1: Determination of the yield and purity of 1-(2,4-dihydroxyphenyl)butan-1-one, an intermediate of [Chemical Formula 1]

[0124] The yield and purity of the intermediate 1-(2,4-dihydroxyphenyl)butan-1-one produced in Example 1 and Comparative Examples 1 to 3 were measured and shown in Table 1 below.

[0125]

Table 1

[0126]

[0127] *DCM is dichloromethane

[0128] As shown in Table 1 described above, when the Friedel-Crafts acylation reaction was carried out while irradiating microwaves (Example 1), the intermediate was obtained in a higher yield compared to the acylation reaction without irradiating microwaves (Comparative Example 1).

[0129] Moreover, when purification was carried out using a mixed solvent composed of dichloromethane and an aqueous sodium chloride solution (Example 1), a higher purity intermediate 1-(2,4-dihydroxyphenyl)butan-1-one was obtained compared to a single solvent of an aqueous sodium chloride solution (Comparative Example 2) and a single solvent of dichloromethane (Comparative Example 3).

[0130] Experimental Example 2: Determination of the Yield and Purity of 4-Butylresorcinol of [Chemical Formula 2]

[0131] The yield and purity of 4-butylresorcinol prepared in Example 2 and Comparative Examples 4 to 6 were determined and shown in Table 2 below.

[0132]

Table 2

[0133]

[0134] As shown in Table 2 described above, when the reduction reaction was carried out under microwave irradiation (Example 2), 4-butylresorcinol was obtained in a high yield and high purity compared to when the reduction reaction was carried out without irradiating microwaves (Comparative Example 4). In addition, it was confirmed that when 4-butylresorcinol was purified in two steps using a first mixed solvent composed of dichloromethane and an aqueous sodium chloride solution and a second mixed solvent composed of dichloromethane and hexane (Example 2), compared to when only the step of extraction using the first mixed solvent composed of dichloromethane and an aqueous sodium chloride solution was carried out and the impurity precipitation step was omitted (Comparative Example 5) or when the step of extraction using the first mixed solvent was omitted and only the step of precipitating impurities using the second mixed solvent composed of dichloromethane and hexane was carried out (Comparative Example 6), 4-butylresorcinol of high purity was obtained.

[0135] The above examples are only used to illustrate the technical solutions of the present invention and are not intended to limit it; although the present invention has been described in detail with reference to the foregoing examples, those skilled in the art can still modify the technical solutions described in the foregoing examples, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for producing 4-alkylresorcinol, comprising: (S10) a step of causing resorcinol to undergo acylation reaction with an acylhalide having a carbon number of C3 to C8 to generate an intermediate; and (S20) a method for producing 4-alkylresorcinol by reducing the carbonyl group of the intermediate, characterized in that at least one of the steps (S10) and (S20) is carried out simultaneously by irradiating with microwaves.

2. The method for producing 4-alkylresorcinol according to claim 1, characterized in that: The microwaves are irradiated at an intensity of 0.1 W / ml to 15 W / mL relative to the microwave intensity per unit volume.

3. The method for producing 4-alkylresorcinol according to claim 1, characterized in that: At least one of the steps (S10) and (S20) is performed in a solvent free manner.

4. The method for producing 4-alkylresorcinol according to claim 1, characterized in that: At least one of the steps (S10) and (S20) is carried out under non-mercury catalysis.

5. The method for producing 4-alkylresorcinol according to claim 1, characterized in that: The step (S10) further comprises a step of purifying the intermediate; the step of purifying the intermediate comprises: (S11) extracting the intermediate using a first organic solvent and a sodium chloride aqueous solution; (S12) A step of precipitating by-products from the extract extracted in step (S11) using a second organic solvent.

6. The method for producing 4-alkylresorcinol according to claim 4, characterized in that: The non-mercury catalyst is zinc powder.

7. The method for producing 4-alkylresorcinol according to claim 6, characterized in that: The zinc powder used in the step (S20) is fed into the reaction in an amount of 12 to 15 equivalents of the intermediate.

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