Method for preparing 6-hydroxy-2H-pyran-3 (6H)-ketone

Abstract

The invention provides a method for preparing 6-hydroxy-2H-pyran-3-ketone, which comprises the following steps: by taking meso-carboxyl phenyl porphyrin (H2TCPP) as a catalyst, oxygen (O2) as an oxidant, cetyl ammonium bromide (CTAB) and potassium phosphate (K3PO4) as auxiliaries and water as a reaction medium, carrying out catalytic oxidation reaction on furfuryl alcohol under natural sunlight for 1 hour, thereby preparing the 6-hydroxy-2H-pyran-3 (6H)-ketone (6-HPO). The 6-hydroxy-2H-pyran-3 (6H)-ketone is obtained through a one-step catalytic oxidation process under mild conditions, a cleaner and more economical catalytic process is achieved, the yield is as high as 98.94%, and the method is low in cost, few in by-product, environmentally friendly, high in atom economic efficiency and good in industrial application prospect.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of chemical engineering, and relates to a method for preparing 6-hydroxy-2H-pyran-3(6H)-one. BACKGROUND

[0002] As a bridge connecting renewable biomass raw materials and traditional bulk chemicals, bio-based furan derivatives are considered to be the most promising platform compounds at present. However, the complex composition and stubborn structure of biomass require the development of effective conversion strategies, i.e. biomass value-added. Among them, the Achmatowicz rearrangement reaction is an expansion ring oxidation reaction, which can oxidize furan derivatives (alkyl-substituted furan, furfuryl alcohol, alkyl-substituted furfuryl alcohol, etc.) into 6-hydroxy-2H-pyran-3(6H)-one with more complex structure and more functionalization. Pyrones and their derivatives are key precursors for monosaccharide synthesis, and can also be used for O-glycosylation, [5+2] cycloaddition, Kishi reduction, Ferrier allylation, metallation, oxidative isomerization and Tsuji-Trost arylation. In addition, 6-hydroxy-2H-pyran-3(6H)-one is also an important intermediate for the synthesis of drugs such as aspergillus lactone and damon information.

[0003] Photocatalytic synthesis is an attractive strategy to expand the methods available for Achmatowicz rearrangement (AR) reaction. In fact, the photo-reaction of furfuryl alcohol was reported in the 1990s, using a 150W visible light as light source, O2 as oxidant, and Bengal rose as catalyst at 0℃ or -78℃ in organic solvent, with a yield of 50%. Later, the reaction was improved in the presence of p-TsOH in H2O, using a 300W xenon lamp for irradiation, with a yield of 50%. Next, Gilmore et al. used [Ru(bpy)3] 2+ As a photocatalyst, it is used in combination with sodium persulfate (Na2S2O8) which is corrosive. Under the condition of photo-oxidation and reduction, [Ru(bpy)3] 2+ and Na2S2O8 generate persulfate, which oxidizes furfuryl alcohol to 6-hydroxy-2H-pyran-3(6H)-one. Usually with a yield of about 80%. In addition, Zhou et al. used tris-Ir(ppy)3 as a photocatalyst. Under visible light irradiation, tris-Ir(ppy)3 photoinduces O2 in the atmosphere to generate singlet oxygen. Furfuryl alcohol is oxidized to 6-hydroxy-2H-pyran-3(6H)-one with a yield of 86%. However, we noticed that almost all reports involving photocatalytic applications use artificial light sources, which require expensive equipment and high-energy light sources. For this reason, the present application carries out photocatalytic reactions under natural sunlight within the effective sunshine time, which is an economically effective method for future possible large-scale catalytic applications.

[0004] The present application shows a new photocatalytic synthesis method for converting furfuryl alcohol into 6-hydroxy-2H-pyran-3(6H)-one. Under the irradiation of natural sunlight, using H2TCPP as a photocatalyst and atmospheric O2 as an oxidant, we found that furfuryl alcohol was converted into 6-hydroxy-2H-pyran-3(6H)-one product. The reaction was carried out at room temperature, the reaction condition was mild, the yield was as high as 98.94%, and the conversion efficiency was as high as 99.9%. Compared with Zhou's method, we did not use [metal]-polypyridyl type photocatalyst, and the oxidation conversion of FAL produced two different types of free radicals, which had obvious advantages such as more excellent product yield, more mild reaction condition, higher atomic efficiency and lower environmental pollution. Therefore, this process is very promising to replace the traditional 6-HPO preparation method in chemical industry. SUMMARY

[0005] The present application is based on the existing 6-hydroxy-2H-pyran-3(6H)-one synthesis method, which has the advantages of industrial application and environmental protection, and provides a synthesis method for 6-hydroxy-2H-pyran-3(6H)-one.

[0006] In order to achieve the above-mentioned application purpose, the technical solution adopted by the present application is:

[0007] A method for preparing 6-hydroxy-2H-pyran-3(6H)-one, using furfuryl alcohol as a starting material, in the presence of a catalyst, under normal pressure, using oxygen as an oxidant, using a surfactant and a basic substance as an auxiliary agent, and irradiating the reaction solution under natural sunlight to prepare 6-hydroxy-2H-pyran-3(6H)-one, the reaction formula is as shown in Figure 1

[0008] The catalyst in the present application is any one of meso-carboxyphenyl porphyrin (H2TCPP), m-tetraphenyl porphyrin (H2TPP), and 5,10,15,20-tetra(4-hydroxyphenyl) porphyrin (H2THPP).

[0009] The mass ratio of furfuryl alcohol to H2TCPP is (20-200):1.

[0010] The volume ratio of the auxiliary agent solution to the FAL solution is (0.1-2):1.

[0011] The light source is any one of natural sunlight, a sunlight simulator, LED white light, and LED blue light.

[0012] The auxiliary agent is any one or more of a surfactant and a basic substance.

[0013] ​The surfactant in the aid is any one of cetyltrimethylammonium bromide (CTAB), cetyltrimethylammonium chloride (CTAC) or sodium dodecyl sulfate (SDS).

[0014] The basic substance in the aid is any one of potassium phosphate (K3PO4), sodium phosphate (Na3PO4) or dipotassium hydrogen phosphate (K2HPO4).

[0015] The features of the present application are:

[0016] (1) The present application carries out photocatalytic reaction under natural sunlight.

[0017] (2) The present application avoids the stoichiometric consumption of toxic or corrosive oxidizing agents, and uses oxygen as the oxygen source.

[0018] (3) The reaction uses water as the solvent, and is carried out at room temperature, so the reaction condition is mild, the environmental pollution is low, and the yield is as high as 98.94%, which has the prospect of industrialization. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is the reaction formula for preparing 6-hydroxy-2H-pyran-3(6H)-one according to the present application.

[0020] Figure 2 is the liquid chromatogram of generating 6-hydroxy-2H-pyran-3(6H)-one according to Example 1. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical scheme and advantages of the present application more clear and explicit, the following further illustrates the present application by combining with specific examples and drawings. It should be understood that the specific examples described herein are only used to explain the present application, but the experimental conditions and set parameters therein should not be regarded as the limitation of the basic technical scheme of the present application. And the protection scope of the present application is not limited to the following examples. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0022] The product with water as the solvent was quantitatively analyzed by using a liquid chromatograph equipped with a TC-C18(2) chromatographic column (170A, 4.6x250㎜, 5um, 400bar pressure limit). The standard curve was prepared by using external standard method, and the conversion rate of FAL and the yield of 6-HPO were calculated.

[0023] Example 1

[0024] The typical procedure for oxidation of FAL under natural sunlight using water as solvent is as follows: 0.1 g of FAL was added to a 10 ml volumetric flask and made up to the mark with water and then sonicated to homogeneity. 0.0050 g of H2TCPP, 0.0730 g of CTAB and 0.0270 g of K3PO4 were added to a conical flask to make 10 ml solution, sealed and stirred overnight (till complete dissolution). 1 ml of FAL solution and 1 ml of catalyst plus additive solution was taken in a conical flask, 8 ml of water was added and stirred to homogeneity. A three-way valve was connected to a balloon to charge O2 into the conical flask. The reaction solution was then kept under natural sunlight and stirring was continued during the reaction. After 60 min of reaction, the reaction mixture was filtered and data was measured on a high performance liquid chromatograph. The conversion of furfuryl alcohol was 99.9% and the yield of 6-hydroxy-2H-pyran-3(6H)-one was 94.66%.

[0025] Example 2

[0026] 0.0050 g of H2THPP, 0.0730 g of CTAB and 0.0270 g of K3PO4 were added to a conical flask to make 10 ml solution, sealed and stirred overnight (till complete dissolution). 1 ml of FAL solution and 1 ml of catalyst plus additive solution was taken in a conical flask, 8 ml of water was added and stirred to homogeneity. A three-way valve was connected to a balloon to charge O2 into the conical flask. The reaction solution was then kept under natural sunlight and stirring was continued during the reaction. After 30 min of reaction, the reaction mixture was filtered and data was measured on a high performance liquid chromatograph. The conversion of furfuryl alcohol was 50.41% and the yield of 6-hydroxy-2H-pyran-3(6H)-one was 50.19%.

[0027] Example 3

[0028] 0.0050 g of H2TCPP, 0.0730 g of CTAB and 0.0270 g of K3PO4 were added to a conical flask to make 10 ml solution, sealed and stirred overnight (till complete dissolution). 0.1 g of FAL and 1 ml of catalyst plus additive solution was taken in a conical flask, 8 ml of water was added and stirred to homogeneity. A three-way valve was connected to a balloon to charge O2 into the conical flask. The reaction solution was then kept under natural sunlight and stirring was continued during the reaction. After 4 h of reaction, the reaction mixture was filtered and data was measured on a high performance liquid chromatograph. The conversion of furfuryl alcohol was 93.54% and the yield of 6-hydroxy-2H-pyran-3(6H)-one was 42.41%.

[0029] Example 4

[0030] 0.1 g FAL was added to a 10 ml volumetric flask and diluted to volume with water, then sonicated until homogeneous. 0.0050 g H2TCPP, 0.0730 g CTAB, and 0.0270 g K3PO4 were added to a conical flask to prepare a 10 ml solution. The flask was sealed and stirred overnight (until completely dissolved). 1 ml of the FAL solution and 1 ml of the catalyst and auxiliary agent solution were added to the conical flask, followed by 8 ml of water and stirring until homogeneous. O2 was introduced into the conical flask via a three-way valve and placed under a sunlight simulator to irradiate the reaction solution. Stirring was maintained throughout the reaction. After 60 minutes, the reaction solution was filtered, and data were determined by high-performance liquid chromatography. The conversion rate of furfuryl alcohol was 99.9%, and the yield of 6-hydroxy-2H-pyran-3(6H)-one was 91.97%.

[0031] Example 5

[0032] Add 0.01g FAL, 0.0005g H2TCPP and 0.0073g CTAB to an Erlenmeyer flask, then add 10ml of water and stir well. Use a three-way valve to connect a balloon to introduce O2 into the Erlenmeyer flask, and then place it under natural sunlight to irradiate the reaction solution. Stir continuously during the reaction. After 60min, filter the reaction solution and perform data analysis by high performance liquid chromatography. The conversion rate of furfuryl alcohol was 99.9%, and the yield of 6-hydroxy-2H-pyran-3(6H)-one was 26.62%.

[0033] Example 6

[0034] Add 0.01g FAL, 0.0005g H2TCPP and 0.0027g K3PO4 to an Erlenmeyer flask, then add 10ml of water and stir well. Use a three-way valve to connect a balloon to introduce O2 into the Erlenmeyer flask, and then place it under natural sunlight to irradiate the reaction solution. Stir continuously during the reaction. After 60min, filter the reaction solution and perform data analysis by high performance liquid chromatography. The conversion rate of furfuryl alcohol was 99.9%, and the yield of 6-hydroxy-2H-pyran-3(6H)-one was 78.74%.

[0035] Example 7

[0036] Example 1

[0037] Example 2

[0038] Example 3

[0039] Example 4

[0040] Example 5

[0041] Example 6

[0042] The 0.1 g FAL was added to a 10 ml volumetric flask with water to constant volume and then ultrasonic homogenized, 0.0050 g H2TCPP, 0.0730 g CTAB and 0.0270 g K3PO4 were added to the conical flask to make a 10 ml solution, sealed and stirred overnight (until completely dissolved), 1 ml FAL solution and 1 ml catalyst and additive solution were taken in a conical flask, 8 ml water was added and stirred evenly, a three-way valve was connected to a balloon to fill O2 into the conical flask, then placed in natural sunlight to irradiate the reaction solution, and stirred continuously during the reaction. After 40 min of reaction, the reaction solution was filtered and the data was determined by high performance liquid chromatography. The conversion rate of furfuryl alcohol was 99.9%, and the yield of 6-hydroxy-2H-pyran-3(6H)-one was 98.94%.

Claims

1. A method for preparing 6-hydroxy-2H-pyran-3(6H)-one, characterized in that, The preparation method uses furfuryl alcohol as the starting material, and in the presence of porphyrin catalyst, under normal pressure, with oxygen as the oxidant and surfactant and alkaline substances as auxiliaries, the reaction solution is irradiated under natural sunlight for 10 min to 60 min to prepare 6-hydroxy-2H-pyran-3(6H)-one.

2. The method for preparing 6-hydroxy-2H-pyran-3-one according to claim 1, characterized in that, The catalyst is any one of mesocarboxyphenylporphyrin H2TCPP, m-tetraphenylporphyrin H2TPP, or 5,10,15,20-tetra(4-hydroxyphenyl)porphyrin H2THPP.

3. The method for preparing 6-hydroxy-2H-pyran-3-one according to claim 1, characterized in that, The mass ratio of furfuryl alcohol to H2TCPP is (20-200):

1.

4. The method for preparing 6-hydroxy-2H-pyran-3-one according to claim 1, characterized in that, The volume ratio of the auxiliary agent solution to the FAL solution is (0.1-2):

1.

5. The method for preparing 6-hydroxy-2H-pyran-3(6H)-one according to claim 1, characterized in that, The light source is any one of natural sunlight, a sunlight simulator, LED white light, or LED blue light.

6. The method for preparing 6-hydroxy-2H-pyran-3-one according to claim 1, characterized in that, The auxiliary agent is any one or more of surfactants or alkaline substances.

7. The method for preparing 6-hydroxy-2H-pyran-3-one according to claim 1, characterized in that, The surfactant in the additive is any one of hexadecyl ammonium bromide (CTAB), hexadecyl ammonium chloride (CTAC), or sodium dodecyl sulfate (SDS).

8. The method for preparing 6-hydroxy-2H-pyran-3-one according to claim 1, characterized in that, The alkaline substances in the additives are potassium phosphate (K3PO4) and sodium phosphate (Na3PO4). 4， Or any one of dipotassium hydrogen phosphate (K2HPO4).

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