Method for preparing cyclopentenone substance through furanol rearrangement-hydrogenolysis

Abstract

The invention discloses a method for preparing cyclopentenone substances through furanol rearrangement-hydrogenolysis, and belongs to the field of fine organic chemicals. The process comprises the following steps: mixing furfuryl alcohol compounds (furfuryl alcohol, 5-methyl furfuryl alcohol and 2, 5-dimethylolfuran) with a water solvent according to different concentrations, adding a cobalt disulfide (CoS2) catalyst, and reacting in a hydrogen environment of 0.5-1.5 MPa at the reaction temperature of 160-200 DEG C; the 2-cyclopentenone / 3-methyl-2-cyclopentenone is obtained by adopting a rearrangement-hydrogenolysis method, the process is simple, the operation is convenient, the catalyst is cheap and easy to obtain and can be recycled for multiple times, and industrialization is easy. When the conversion rate of 2-cyclopentenone synthesized by furfuryl alcohol reaches up to 100%, the yield reaches up to 90%; when the conversion rate of the 3-methyl-2-cyclopentenone synthesized from the 5-methylfuranol and the 2, 5-dimethylolfuran is up to 100%, the yields are up to 80% and 78% respectively.

Description

Technical Field

[0001] The invention belongs to the field of fine organic chemicals, and specifically relates to a method for preparing cyclopentenone substances by rearrangement-hydrogenolysis of furanol. Background Art

[0002] The conversion of furan alcohols (furfuryl alcohol, 5-methylfuran alcohol, 2,5-dihydroxymethylfuran) to cyclopentenones (2-cyclopentenone, 3-methyl-2-cyclopentenone) has been widely reported by rearrangement to 4-hydroxy-2-cyclopentenone, hydrogenolysis to 2-cyclopentenone, and reduction metal / solid acid hydrogenation steps in water (2.0-8.0 MPa H2 pressure, 140-180 °C). Although it is theoretically possible to synthesize 2-cyclopentenone via controlled rearrangement-hydrogenolysis of furan alcohols, the hydrogenation rate of 2-cyclopentenone is often faster than that of furfuryl alcohol rearrangement and 4-hydroxy-2-cyclopentenone hydrogenolysis. Active 4-hydroxy-2-cyclopentenone is difficult to preserve and can only be obtained with selectivities below 2%. To our knowledge, furan alcohols have been used to produce 2-cyclopentenone in 52.3% yield over a double metal cyanide catalyst that can activate H2 via a surface-frustrated Lewis Zn-N heteropolynary activation. However, in most studies, the major products are concentrated on furanol-derived 2-cyclopentenone, 5-methylfuranol, and 2,5-dihydroxymethylfuran-derived 3-methyl-2-cyclopentenone, which have been rarely reported so far, indicating that the selective rearrangement-hydrogenolysis of furanols to cyclopentenones in high yields while maintaining good catalytic acceptability is very challenging.

[0003] On the other hand, cyclopentenone compounds (such as 2-cyclopentenone and 3-methyl-2-cyclopentenone) are important components of natural products, drug molecules and bulk chemicals. They are also universal synthetic reactants in a variety of organic transformations (such as Michael addition, Diels-Alder and Heck reactions) because they contain both active olefins and carbonyl groups in a small cyclopentyl molecule. Therefore, the development of new raw materials and new routes for the preparation of cyclopentenone substances, especially the use of cheap and abundant biomass resources, is of great research significance. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing cyclopentenones by rearrangement-hydrogenolysis of furanol. The process is simple, easy to operate, and has mild reaction conditions. Cobalt disulfide (CoS2) is cheap and easy to obtain as a catalyst and can be recycled many times, making it easy to industrialize. Huang Yong et al. studied the hydrogenolysis and acid catalysis of cellulose using different forms of cobalt disulfide. The results showed that different forms of cobalt disulfide resulted in proportional differences in their acid numbers, and the unique activities of different cobalt disulfides were also reflected in the conversion of cellulose. Therefore, cobalt disulfide (CoS2), as a cheap heterogeneous catalyst, can play a role in acid catalysis and hydrogenolysis reactions by controlling its morphology, and is a type of catalyst worth developing.

[0005] The present invention is achieved through the following technical solutions: The present invention provides a method for preparing cyclopentenone substances by rearrangement-hydrogenolysis of furanol, comprising the following steps: Step 1: dissolving cobalt salt and thiourea in water, adjusting the pH and heating the reaction to obtain multi-layered cobalt disulfide, which is then dried and used as a catalyst for later use; Step 2: Mix the furanol compound with water, add the catalyst obtained in step 1, react under hydrogen pressure, and obtain cyclopentenone substances after cooling.

[0006] Furthermore, the cobalt salt in step 1 is CoCl2·6H2O.

[0007] Furthermore, in step 1, the pH is adjusted to 10, the heating reaction temperature is 200° C., and the reaction time is 12 h.

[0008] Furthermore, the furanol compounds in step 2 include furfuryl alcohol, 5-methylfuranol, and 2,5-dihydroxymethylfuran.

[0009] Furthermore, in step 2, the concentration of the furanol compound after mixing with water is 0.05-0.15 mol / L.

[0010] Furthermore, the reaction conditions of hydrogen pressurization in step 2 are: pressure 0.5-1.5 MPa, temperature 160-200° C., and reaction time 6 h.

[0011] Furthermore, the cyclopentenone substance in step 2 includes: 2-cyclopentenone and 3-methyl-2-cyclopentenone.

[0012] The reaction formula is as follows:

[0013] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention provides a method for rearrangement-hydrogenolysis of furan alcohol compounds to obtain 2-cyclopentenone / 3-methyl-2-cyclopentenone. The preparation method of the catalytic material used is easy to operate, the catalyst is cheap and easy to obtain, the catalytic activity selectivity is high, and it can be recycled for multiple times, which is easy to industrialize.

[0014] 2. The raw materials used in the present invention are synthesized based on hemicellulose platform compounds, which reduces excessive dependence on petroleum and reduces halogen pollution environmental problems.

[0015] 3. When the conversion rate of furfuryl alcohol to synthesize 2-cyclopentenone is as high as 100%, the yield is as high as 90%; when the conversion rate of 5-methylfurfuryl alcohol to synthesize 3-methyl-2-cyclopentenone is as high as 100%, the yield is as high as 80%; when the conversion rate of 2,5-dihydroxymethylfuran is as high as 100%, the yield is as high as 78%. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be clearly and completely described below in conjunction with the embodiments. If the specific conditions are not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.

[0017] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0018] Example 1: Preparation of cobalt disulfide (CoS2) catalyst 2.4 mmol CoCl2·6H2O and 4 mmol thiourea were dissolved in 50 mL deionized water. The pH of the solution was then adjusted to about 10 using KOH. The solution was transferred to a 100 mL polytetrafluoroethylene-lined stainless steel autoclave at 200 °C for 12 h. After the reaction, CoS2 was washed several times with ethanol and deionized water and then dried in a vacuum oven at 60 °C for 10 h. The obtained CoS2 catalyst was used to catalyze furfuryl alcohol.

[0019] Example 2: Preparation of 2-cyclopentenone Weigh 73.6 mg of furfuryl alcohol and 15 mL of water into a 25 mL reactor, then add 0.1 g of catalyst (CoS2), replace the air in the reactor with reducing gas H2 at a pressure of 0.5 MPa five to six times to reduce the oxygen content in the reactor, and then heat to 160°C and maintain for 6 hours. Wait for the reaction to end, quickly cool to room temperature, and collect samples.

[0020] For Examples 3-10, except for the different implementation conditions mentioned in the table below, the rest of the operation methods are the same as Example 2.

[0021] The reaction conditions and sample properties of Examples 2-10 are shown in Table 1.

[0022] Table 1. Preparation Examples of 2-cyclopentenone catalyst Solvents Reactant Type Reactant concentration (mol / L) Reaction temperature (℃) Hydrogen pressure (MPa) Conversion rate (%) Yield (%) Example 2 <![CDATA[CoS2]]> water Furfuryl alcohol 0.05 160 0.5 79 41 Example 3 <![CDATA[CoS2]]> water Furfuryl alcohol 0.05 180 1.5 100 64 Example 4 <![CDATA[CoS2]]> water Furfuryl alcohol 0.05 200 1 100 58 Example 5 <![CDATA[CoS2]]> water Furfuryl alcohol 0.1 160 1.5 75 52 Example 6 <![CDATA[CoS2]]> water Furfuryl alcohol 0.1 180 1 100 90 Example 7 <![CDATA[CoS2]]> water Furfuryl alcohol 0.1 200 0.5 100 73 Example 8 <![CDATA[CoS2]]> water Furfuryl alcohol 0.15 160 1 72 41 Example 9 <![CDATA[CoS2]]> water Furfuryl alcohol 0.15 180 0.5 75 35 Example 10 <![CDATA[CoS2]]> water Furfuryl alcohol 0.15 200 1.5 84 46 As can be seen from Table 1, the catalyst of the present invention can achieve efficient catalytic rearrangement hydrogenolysis of furan alcohol compounds. In particular, in the case of Example 6, the selectivity of furfuryl alcohol rearrangement hydrogenolysis to synthesize 2-cyclopentenone is as high as 90%, and the effect is the best.

[0023] Example 11: Preparation of 3-methyl-2-cyclopentenone Weigh 84 mg of 5-methylfurfuryl alcohol and 15 mL of water into a 25 mL reactor, then add 0.1 g of catalyst (CoS2), and replace the air in the reactor with reducing gas H2 at a pressure of 0.5 MPa for five to six times to reduce the oxygen content in the reactor. Heat to 160°C and maintain for 6 hours. Wait for the reaction to end, quickly cool to room temperature, and collect samples.

[0024] For Examples 12-28, except for the different implementation conditions mentioned in the table below, the rest of the operation methods are the same as Example 11.

[0025] The reaction conditions and sample properties of Examples 11-28 are shown in Table 2.

[0026] Table 2. Preparation Example of 3-methyl-2-cyclopentenone catalyst Solvents Reactant Type Reactant concentration (mol / L) Reaction temperature (℃) Hydrogen pressure (MPa) Conversion rate (%) Yield (%) Embodiment 11 <![CDATA[CoS2]]> water 5-Methylfurfuryl alcohol 0.05 160 0.5 92 68 Example 12 <![CDATA[CoS2]]> water 5-Methylfurfuryl alcohol 0.05 180 1.5 100 48 Example 13 <![CDATA[CoS2]]> water 5-Methylfurfuryl alcohol 0.05 200 1 100 51 Embodiment 14 <![CDATA[CoS2]]> water 5-Methylfurfuryl alcohol 0.1 160 1.5 72 23 Embodiment 15 <![CDATA[CoS2]]> water 5-Methylfurfuryl alcohol 0.1 180 1 100 80 Example 16 <![CDATA[CoS2]]> water 5-Methylfurfuryl alcohol 0.1 200 0.5 100 42 Embodiment 17 <![CDATA[CoS2]]> water 5-Methylfurfuryl alcohol 0.15 160 1 42 16 Embodiment 18 <![CDATA[CoS2]]> water 5-Methylfurfuryl alcohol 0.15 180 0.5 50 37 Embodiment 19 <![CDATA[CoS2]]> water 5-Methylfurfuryl alcohol 0.15 200 1.5 96 57 Embodiment 20 <![CDATA[CoS2]]> water 2,5-Dihydroxymethylfuran 0.05 160 0.5 84 44 Embodiment 21 <![CDATA[CoS2]]> water 2,5-Dihydroxymethylfuran 0.05 180 1.5 100 56 Embodiment 22 <![CDATA[CoS2]]> water 2,5-Dihydroxymethylfuran 0.05 200 1 100 68 Embodiment 23 <![CDATA[CoS2]]> water 2,5-Dihydroxymethylfuran 0.1 160 1.5 75 32 Embodiment 24 <![CDATA[CoS2]]> water 2,5-Dihydroxymethylfuran 0.1 180 1 100 78 Embodiment 25 <![CDATA[CoS2]]> water 2,5-Dihydroxymethylfuran 0.1 200 0.5 100 64 Embodiment 26 <![CDATA[CoS2]]> water 2,5-Dihydroxymethylfuran 0.15 160 1 23 12 Embodiment 27 <![CDATA[CoS2]]> water 2,5-Dihydroxymethylfuran 0.15 180 0.5 61 39 Embodiment 28 <![CDATA[CoS2]]> water 2,5-Dihydroxymethylfuran 0.15 200 1.5 87 52 As can be seen from Table 2, in the case of Example 15, the selectivity of 5-methylfurfuryl alcohol rearrangement hydrogenolysis to synthesize 3-methyl-2-cyclopentenone is as high as 80%, and it is universal to the reaction of 2,5-dihydroxymethylfuran. In the case of Example 24, the selectivity of 2,5-dihydroxymethylfuran rearrangement hydrogenolysis to synthesize 3-methyl-2-cyclopentenone is as high as 78%.

[0027] In summary, 2-cyclopentenone and 3-methyl-2-cyclopentenone can be obtained through the above two different synthetic routes. After analysis, for the synthesis of 2-cyclopentenone from furfuryl alcohol, when the conversion rate is as high as 100%, the yield is as high as 90%; for the synthesis of 3-methyl-2-cyclopentenone from 5-methylfurfuryl alcohol, when the conversion rate is as high as 100%, the yield is as high as 80%; and for 2,5-dihydroxymethylfuran, when the conversion rate is as high as 100%, the yield is as high as 78%.

[0028] The embodiments described above only express several preferred embodiments of the present invention, and the descriptions thereof are relatively specific and detailed, but are not intended to limit the present invention. It should be noted that for those skilled in the art, the present invention may also have various changes and modifications, and any modifications, equivalent substitutions, improvements, etc. made within the concept and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing cyclopentenones by rearrangement-hydrogenolysis of furanol, characterized in that: The following steps are involved: Step 1: dissolving cobalt salt and thiourea in water, adjusting the pH and heating the reaction to obtain multi-layered cobalt disulfide, which is then dried and used as a catalyst for later use; Step 2: Mix the furanol compound with water, add the catalyst obtained in step 1, react under hydrogen pressure, and obtain cyclopentenone substances after cooling.

2. The method for preparing cyclopentenones by rearrangement-hydrogenolysis of furanol according to claim 1, characterized in that: The cobalt salt in step 1 is CoCl2·6H2O.

3. The method for preparing cyclopentenones by rearrangement-hydrogenolysis of furanol according to claim 1, characterized in that: In step 1, the pH was adjusted to 10, the heating reaction temperature was 200° C., and the reaction time was 12 h.

4. The method for preparing cyclopentenones by rearrangement-hydrogenolysis of furanol according to claim 1, characterized in that: The furan alcohol compounds in step 2 include furfuryl alcohol, 5-methyl furanol and 2,5-dihydroxymethyl furan.

5. The method for preparing cyclopentenones by rearrangement-hydrogenolysis of furanol according to claim 1, characterized in that: In step 2, the concentration of the furanol compound after mixing with water is 0.05-0.15 mol / L.

6. The method for preparing cyclopentenones by rearrangement-hydrogenolysis of furanol according to claim 1, characterized in that: The reaction conditions of hydrogen pressurization in step 2 are: pressure 0.5-1.5 MPa, temperature 160-200° C., and reaction time 6 h.

7. The method for preparing cyclopentenones by rearrangement-hydrogenolysis of furanol according to claim 1, characterized in that: The cyclopentenone substances in step 2 include: 2-cyclopentenone and 3-methyl-2-cyclopentenone.

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