A method for preparing cyclopentenone substances by furan alcohol rearrangement-hydrogenolysis

Abstract

The application discloses a method for preparing cyclopentenone substances by furan alcohol rearrangement-hydrogenolysis, and belongs to the field of fine organic chemicals. In the method, furan alcohol compounds (furfuryl alcohol, 5-methyl furan alcohol and 2,5-dihydroxymethyl furan) are mixed with water solvent in different concentrations, a cobalt disulfide (CoS2) catalyst is added, and the mixture is reacted in a hydrogen environment with a pressure of 0.5-1.5 MPa at a reaction temperature of 160-200 DEG C. The method can obtain 2-cyclopentenone / 3-methyl-2-cyclopentenone, and has the advantages of simple process, convenient operation, cheap and easily obtained catalyst and multiple recycling, and is easy to be industrialized. When the conversion rate of furfuryl alcohol for synthesizing 2-cyclopentenone reaches 100%, the yield reaches 90%; when the conversion rate of 5-methyl furan alcohol and 2,5-dihydroxymethyl furan for synthesizing 3-methyl-2-cyclopentenone reaches 100%, the yields reach 80% and 78% respectively.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of fine organic chemicals, and particularly relates to a method for preparing cyclopentenone compounds by rearrangement-hydrogenolysis of furfuryl alcohol. BACKGROUND

[0002] Methods for converting furfuryl alcohol (furfuryl alcohol, 5-methylfurfuryl alcohol, 2,5-dihydroxymethylfurfuryl alcohol) into cyclopentenone (2-cyclopentenone, 3-methyl-2-cyclopentenone) have been widely reported, which is achieved by rearrangement into 4-hydroxy-2-cyclopentenone, hydrogenolysis into 2-cyclopentenone and reduction metal / solid acid hydrogenation steps in water (2.0-8.0 MPa H2 pressure, 140-180℃ temperature). Although 2-cyclopentenone can be theoretically synthesized by controlled rearrangement-hydrogenolysis of furfuryl alcohol, the hydrogenation rate of 2-cyclopentenone is often faster than the rearrangement of furfuryl alcohol and the hydrogenolysis of 4-hydroxy-2-cyclopentenone. Active 4-hydroxy-2-cyclopentenone is difficult to store and can only be obtained with a selectivity of less than 2%. To our knowledge, the yield of 2-cyclopentenone from furfuryl alcohol on a double-metal cyanide catalyst is 52.3%, which can activate H2 through a Lewis Zn-N pair on the surface of the catalyst. However, in most studies, the main products are concentrated in 2-cyclopentenone derived from furfuryl alcohol, 3-methyl-2-cyclopentenone derived from 5-methylfurfuryl alcohol and 2,5-dihydroxymethylfurfuryl alcohol, and so far there has been almost no report, which indicates that it is very challenging to selectively rearrange-hydrogenolysis furfuryl alcohol to cyclopentenone with high yield while maintaining good catalytic tolerance.

[0003] On the other hand, cyclopentenone compounds (such as 2-cyclopentenone, 3-methyl-2-cyclopentenone) are important components of natural products, drug molecules and bulk chemicals, and are also common synthetic reactants in various organic transformations (such as Michael addition, Diels-Alder and Heck reaction), because they contain both active alkenes and carbonyl groups in one small cyclopentyl molecule, therefore, it is of great significance to develop new raw materials and new routes for the preparation of cyclopentenone compounds, especially using cheap and abundant biomass resources. SUMMARY

[0004] The application aims to provide a method for preparing cyclopentenone substances by furan alcohol rearrangement-hydrogenolysis, which is simple in process, convenient to operate, mild in reaction condition, cheap and easy to recycle as a catalyst, and easy to industrialize.

[0005] The application is achieved by the following technical solutions:

[0006] The application provides a method for preparing cyclopentenone substances by furan alcohol rearrangement-hydrogenolysis, which comprises the following steps:

[0007] Step one: dissolve cobalt salt and thiourea in water, adjust pH and heat to react to prepare multi-layer flaky cobalt disulfide, and dry to prepare the catalyst for standby;

[0008] Step two: mix furan alcohol compounds with water, add the catalyst prepared in step one, and react under hydrogen pressure, and then cool to obtain cyclopentenone substances.

[0009] Further, the cobalt salt in step one is CoCl2·6H2O.

[0010] Further, the pH in step one is adjusted to 10, the heating reaction temperature is 200 DEG C, and the reaction time is 12 h.

[0011] Further, the furan alcohol compounds in step two include furfuryl alcohol, 5-methyl furfuryl alcohol and 2,5-dihydroxymethyl furan.

[0012] Further, the concentration of the furan alcohol compounds mixed with water in step two is 0.05-0.15 mol / L.

[0013] Further, the reaction condition of hydrogen pressure in step two is: pressure 0.5-1.5 MPa, temperature 160-200 DEG C, and reaction time 6 h.

[0014] Further, the cyclopentenone substances in step two include 2-cyclopentenone and 3-methyl-2-cyclopentenone.

[0015] The reaction formula is as follows:

[0016]

[0017] Compared with the prior art, the present application has the following advantages:

[0018] 1. The present application provides a method for rearrangement-hydrogenolysis of furanic alcohols 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 and selectivity are high, and the catalyst can be recycled multiple times, which is easy to industrialize.

[0019] 2. The raw material used in the present application is synthesized based on a hemicellulose platform compound, which reduces the over-reliance on petroleum and reduces the problem of halogen pollution of the environment.

[0020] 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%; and when the conversion rate of 2,5-dihydroxymethylfuran is as high as 100%, the yield is as high as 78%. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme of the present application will be described clearly and completely below in combination with examples. If the specific conditions are not specified in the examples, the conventional conditions or the conditions recommended by the manufacturer are used. If the reagents or instruments used are not specified by the manufacturer, they are all conventional products that can be purchased on the market.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the present application is only for the purpose of describing specific embodiments and is not intended to limit the present application. The term "and / or" used herein includes any and all combinations of one or more of the associated listed items.

[0023] Example 1: Preparation of cobalt disulfide (CoS2) catalyst

[0024] 2.4 mmol of CoCl2·6H2O and 4 mmol of thiourea were dissolved in 50 mL of deionized water. Then the pH value of the solution was adjusted to about 10 using KOH. The solution was transferred to a 100 mL polytetrafluoroethylene-lined stainless steel autoclave, the temperature was 200℃, and the reaction was continued for 12 hours. After the reaction was completed, the CoS2 was washed with ethanol and deionized water several times, and then dried in a vacuum oven at 60℃ for 10 hours. The obtained CoS2 catalyst was used to catalyze furfuryl alcohol.

[0025] Example 2: Preparation of 2-cyclopentenone

[0026] Take 73.6 mg of furfuryl alcohol and 15 mL of water into a 25 mL reaction kettle, then add 0.1 g of catalyst (CoS2), displace the air in the kettle with reducing gas H2, pressure 0.5 MPa, five to six times, reduce the oxygen content in the kettle, then heat to 160°C and maintain for 6 hours. Wait for the reaction to end, quickly cool to room temperature, and collect the sample.

[0027] For examples 3-10, the remaining operation methods are the same as example 2, except for the different implementation conditions mentioned in the table below.

[0028] The reaction conditions and sample properties of examples 2-10 are shown in table 1.

[0029] Table 1. 2-cyclopentenone preparation examples

[0030] Catalyst Solvent Reactant species Reactant concentration (mol / L) Reaction temperature (°C) Hydrogen pressure (MPa) Conversion rate (%) Yield (%) Example 2 CoS2 Water Furfuryl alcohol 0.05 160 0.5 79 41 Example 3 CoS2 Water Furfuryl alcohol 0.05 180 1.5 100 64 Example 4 CoS2 Water Furfuryl alcohol 0.05 200 1 100 58 Example 5 CoS2 Water Furfuryl alcohol 0.1 160 1.5 75 52 Example 6 CoS2 Water Furfuryl alcohol 0.1 180 1 100 90 Example 7 CoS2 Water Furfuryl alcohol 0.1 200 0.5 100 73 Example 8 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 CoS2 Water Furfuryl alcohol 0.15 200 1.5 84 46

[0031] As can be seen from table 1, the catalysts of the present application can achieve efficient catalysis of furan alcohol rearrangement hydrogenolysis. Among them, 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.

[0032] Example 11: 3-methyl-2-cyclopentenone preparation

[0033] Take 84 mg of 5-methyl furfuryl alcohol and 15 mL of water into a 25 mL reaction kettle, then add 0.1 g of catalyst (CoS2), displace the air in the kettle with reducing gas H2, pressure 0.5 MPa, five to six times, reduce the oxygen content in the kettle. Then heat to 160°C and maintain for 6 hours. Wait for the reaction to end, quickly cool to room temperature, and collect the sample.

[0034] For examples 12-28, the remaining operation methods are the same as example 11, except for the different implementation conditions mentioned in the table below.

[0035] The reaction conditions and sample properties of examples 11-28 are shown in table 2.

[0036] Table 2. 3-methyl-2-cyclopentenone preparation examples

[0037] Catalyst Solvent Reactant species Reactant concentration (mol / L) Reaction temperature (°C) Hydrogen pressure (MPa) Conversion rate (%) Yield (%) Example 11 CoS2 Water 5-methylfurfuryl alcohol 0.05 160 0.5 92 68 Example 12 CoS2 Water 5-methylfurfuryl alcohol 0.05 180 1.5 100 48 Example 13 CoS2 Water 5-methylfurfuryl alcohol 0.05 200 1 100 51 Example 14 CoS2 Water 5-methylfurfuryl alcohol 0.1 160 1.5 72 23 Example 15 CoS2 Water 5-methylfurfuryl alcohol 0.1 180 1 100 80 Example 16 CoS2 Water 5-methylfurfuryl alcohol 0.1 200 0.5 100 42 Example 17 CoS2 Water 5-methylfurfuryl alcohol 0.15 160 1 42 16 Example 18 CoS2 Water 5-methylfurfuryl alcohol 0.15 180 0.5 50 37 Example 19 CoS2 Water 5-methylfurfuryl alcohol 0.15 200 1.5 96 57 Example 20 CoS2 Water 2,5-dihydroxymethylfuran 0.05 160 0.5 84 44 Example 21 CoS2 Water 2,5-dihydroxymethylfuran 0.05 180 1.5 100 56 Example 22 CoS2 Water 2,5-dihydroxymethylfuran 0.05 200 1 100 68 Example 23 CoS2 Water 2,5-dihydroxymethylfuran 0.1 160 1.5 75 32 Example 24 CoS2 Water 2,5-dihydroxymethylfuran 0.1 180 1 100 78 Example 25 CoS2 Water 2,5-dihydroxymethylfuran 0.1 200 0.5 100 64 Example 26 CoS2 Water 2,5-dihydroxymethylfuran 0.15 160 1 23 12 Example 27 CoS2 Water 2,5-dihydroxymethylfuran 0.15 180 0.5 61 39 Example 28 CoS2 Water 2,5-dihydroxymethylfuran 0.15 200 1.5 87 52

[0038] As can be seen from table 2, in the case of example 15, the selectivity of 5-methyl furfuryl alcohol rearrangement hydrogenolysis to synthesize 3-methyl-2-cyclopentenone is as high as 80%, and it has universality for 2,5-dihydroxymethyl furan reaction, in the case of example 24, the selectivity of 2,5-dihydroxymethyl furan rearrangement hydrogenolysis to synthesize 3-methyl-2-cyclopentenone is as high as 78%.

[0039] In summary, 2-cyclopentenone and 3-methyl-2-cyclopentenone can be obtained by the above two different synthetic routes. For the synthesis of 2-cyclopentenone from furfuryl alcohol, the yield can reach 90% when the conversion rate is up to 100%; for the synthesis of 3-methyl-2-cyclopentenone from 5-methylfurfuryl alcohol, the yield can reach 80% when the conversion rate is up to 100%; and for the synthesis of 2,5-dihydroxymethylfuran, the yield can reach 78% when the conversion rate is up to 100%.

[0040] The above described embodiments only express several preferred embodiments of the present application, which are described in a more specific and detailed manner, but are not used to limit the present application. It should be noted that the present application can also have various changes and modifications for those skilled in the art, and any modification, equivalent replacement, improvement, etc. made within the concept and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing cyclopentenones by rearrangement-hydrogenolysis of furanol, characterized in that: The following steps are involved: Step 1: Dissolve cobalt salt and thiourea in water, adjust the pH, and heat the reaction to obtain multilayered cobalt disulfide, which is then dried and used as a catalyst. The pH was adjusted to 10, the heating reaction temperature was 200°C, and the reaction time was 12 h. Step 2: mixing the furanol compound with water, adding the catalyst obtained in step 1, reacting under hydrogen pressure, and cooling to obtain cyclopentenone substances; The furanol compound is furfuryl alcohol, 5-methylfuranol or 2,5-dihydroxymethylfuran; the reaction conditions for hydrogen pressurization are: pressure 0.5-1.5 MPa, temperature 160-200°C, and reaction time 6 h; the cyclopentenone substance is: 2-cyclopentenone or 3-methyl-2-cyclopentenone.

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

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

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