A catalyst for synthesizing 1,2-pentanediol and a preparation method thereof

Abstract

The present invention provides a fixed-bed catalyst for synthesizing 1,2-pentanediol and a preparation method thereof. The catalyst of the present invention uses alumina modified by alkali metal and / or alkaline earth metal salts as a carrier, and is obtained by loading a small amount of transition metals and rare earth metals, and has the characteristics of large specific surface area and high dispersion of active metals. Using furfural and / or furfuryl alcohol as raw materials, under mild reaction conditions, the catalyst can realize one-step hydrogenation to produce 1,2-pentanediol on a fixed-bed reactor, with a raw material conversion rate of 100%, a selectivity of 1,2-pentanediol greater than 50%, and a single-pass life of the catalyst greater than 8,000 hours. The catalyst of the present invention has the advantages of high conversion rate, high selectivity and long life, and can be applied to the industrial production of 1,2-pentanediol.

Description

Technical Field

[0001] The present invention belongs to the technical field of synthesis of high - value - added chemicals from biomass - based materials, and particularly relates to a catalyst for catalytic hydrogenation of furfural and / or furfuryl alcohol to synthesize 1,2 - pentanediol and a preparation method thereof. Background Art

[0002] With the extensive use of fossil resources, the problems of energy shortage and environmental pollution have become increasingly prominent. Seeking an efficient and environmentally friendly alternative resource has become a current research hotspot. Biomass has significant characteristics such as being renewable, having a large reserve, and being widely distributed, and it is the only renewable resource that can be used to synthesize chemicals. Furfural and furfuryl alcohol, as an important platform compound obtained by catalytic conversion of biomass, can obtain various high - value - added products such as tetrahydrofurfuryl alcohol, 1,2 - pentanediol, and 1,5 - pentanediol through catalytic hydrogenation. Among them, 1,2 - pentanediol, as an important fine chemical intermediate, is an important raw material for synthesizing the fungicide propiconazole. At the same time, 1,2 - pentanediol is widely used in the cosmetic field due to its moisturizing effect and ability to dissolve poorly soluble active ingredients.

[0003] In recent years, the preparation of 1,2 - pentanediol by selective hydrogenolysis using furfuryl alcohol or furfural as raw materials has received increasing attention. Patent CN104016831A uses a 5% Ru / Al 2 O 3 catalyst. Using furfuryl alcohol as the raw material, at 200 °C and 100 bar H 2 conditions, the yield of 1,2 - pentanediol is about 34%. US Patent US20140066666A1 uses 5% Pt / Al 2 O 3 as the catalyst, and furfuryl alcohol achieved a 1,2 - pentanediol yield of 80% under the reaction conditions of 0 - 5 °C and 1 bar H 2 . In the aspect of hydrogenolysis of furfural to 1,2 - pentanediol, Patent CN112672990A uses 4.1% Ru - 5Sn / ZnO as the hydrogenation catalyst, and the yield of 1,2 - pentanediol obtained under the reaction conditions of 140 °C and 35 Bar H 2 is 87.3%. In the above - mentioned patents, the process of preparing 1,2 - pentanediol by hydrogenolysis needs to be carried out in a batch autoclave and requires a large amount of precious metals to be loaded. The catalyst loss is large and the recovery cost is high, which limits its industrial application. Patent CN105130746A uses 10Cu - Mg 3 AlO 4.5 as the catalyst, at 140 °C and 8 MPa H 2The yield of 1,2-pentanediol obtained after 8 hours of reaction was 52.1%. In Patent CN102924232A, a composite oxide of copper oxide was also used for the hydrogenolysis of furfural to 1,2-pentanediol. Under the conditions of 100-200 °C and 4.0-10.0 MPa, the yield of 1,2-pentanediol was less than 50%. The above method uses a non-noble metal catalyst, which has a low catalyst cost, but the reaction conditions are harsh and there are high requirements for equipment and operation. Patent CN109608304A uses an autoclave reaction vessel, with an amorphous alloy as the catalyst and furfural as the raw material. Under the conditions of 120-180 °C and 0.5-2.0 MPa, the yield of 1,2-pentanediol is also less than 50%. Although the reaction conditions are mild and the catalyst cost is relatively low, the yield of 1,2-pentanediol is low and the by-products are complex.

[0004] In summary, most of the current processes for the hydrogenolysis of furfuryl alcohol or furfural to prepare 1,2-pentanediol use batch autoclave reactors, which have complex operations and have disadvantages such as a high noble metal loading, or a low product yield and harsh reaction conditions, restricting their industrial promotion and application. How to both increase the product yield and reduce the losses caused by the process operation to the catalyst and the requirements for equipment and operation remains a huge challenge. Summary of the Invention

[0005] The object of the present invention is to provide a fixed-bed catalyst with high selectivity and high activity in view of the deficiencies of the prior art. This catalyst has characteristics such as a high specific surface area, a high dispersion degree of active metals, and a long service life, and is suitable for industrial continuous production.

[0006] The catalyst prepared by the present inventor can realize the one-step hydrogenation of furfuryl alcohol and / or furfural to prepare 1,2-pentanediol on a fixed-bed reactor. The raw material conversion rate reaches 100%, the selectivity of 1,2-pentanediol is greater than 50%, and at the same time, high-value-added tetrahydrofurfuryl alcohol is produced as a by-product. Moreover, the sum of the selectivities of 1,2-pentanediol and tetrahydrofurfuryl alcohol is greater than 99%. The product composition is simple and easy to separate.

[0007] The present invention provides a catalyst for synthesizing 1,2-pentanediol and a preparation method thereof, as well as a method for preparing 1,2-pentanediol using this catalyst.

[0008] Specifically, it includes the following steps:

[0009] A catalyst for synthesizing 1,2-pentanediol and a preparation method thereof, characterized in that the catalyst uses alumina modified with alkali metal and / or alkaline earth metal salts as the carrier, and a transition metal and a rare earth metal are loaded to obtain a catalyst with a specific surface area of 220-400 m 2 / g.

[0010] The above alkali metal or alkaline earth metal salt is Mg(NO 3 ) 2, Ca(NO 3 ) 2 , Ba(NO 3 ) 2 , KNO 3 , NaNO 3 One or more of;

[0011] The above transition metals are one or more of Ru, Pt, Pd, Ni, Cu;

[0012] The above rare earth metals are one or more of La, Ce, Sm.

[0013] The specific surface area of the catalyst is 220 - 400 m 2 / g, preferably 280 - 350 m 2 / g.

[0014] The content of the alkali metal and / or alkaline earth metal accounts for 0.5 - 10.0% of the total weight of the catalyst, preferably 1.5 - 5.0%.

[0015] The content of the transition metal accounts for 0.1 - 1.0% of the total weight of the catalyst, preferably 0.4 - 0.8%.

[0016] The content of the rare earth metal accounts for 0.01 - 5.0% of the total weight of the catalyst, preferably 0.5 - 2.5%.

[0017] Using the catalyst prepared by the above method, with furfuryl alcohol, furfural or a mixture of the two as raw materials, mixed and fed with a solvent in a mass ratio of 1:2.0 - 5.0, the solvent is selected from water, tetrahydrofurfuryl alcohol, n-butanol, 1-pentanol, isopropanol, and hydrogenation reaction is carried out in a fixed-bed reactor under a H 2 environment, at a temperature of 100 - 200 °C, to obtain 1,2-pentanediol and tetrahydrofurfuryl alcohol.

[0018] After the catalyst support of the present invention is modified, it has the characteristics of a large specific surface area, high dispersion of the supported active metal, and many active centers of the catalyst.

[0019] The catalyst of the present invention operates for 8000 h in a continuous reaction system, the raw material conversion rate is 100%, the selectivity of 1,2-pentanediol is greater than 50%, and the total selectivity of 1,2-pentanediol and tetrahydrofurfuryl alcohol is greater than 99%.

[0020] The present invention is further described in detail by the following specific examples, but the protection scope of the present invention is not limited thereto.

[0021] Example 1

[0022] 200 g of the support was treated with Mg(NO 3 ) 2After modification, the obtained modified support was impregnated isovolumetrically in an aqueous mixed solution of ruthenium nitrate and lanthanum nitrate, and after drying, calcination, and reduction, a catalyst 1 with 0.5% Mg content, 1% Ru content, 0.5% La content, and a specific surface area of 280 m 2 / g was obtained.

[0023] 200 g of catalyst 1 was placed in a fixed-bed reactor, and a mixed solution with a mass ratio of water to furfuryl alcohol of 2:1 was continuously fed with H 2 at a controlled reaction temperature of 200 °C and a reaction pressure of 1 MPa. After reacting for 2 hours, the product was collected for analysis. The conversion rate of furfuryl alcohol was 100%, the selectivity for 1,2-pentanediol was 55%, and the selectivity for tetrahydrofurfuryl alcohol was 45.5%.

[0024] Example 2

[0025] After the 200 g support was modified with metal KNO 3 it was then impregnated isovolumetrically in an aqueous mixed solution of chloroplatinic acid and samarium nitrate. After drying, calcination, and reduction, a catalyst 2 with 3% K content, 0.4% Pt content, 0.01% Sm content, and a specific surface area of 350 m 2 / g was obtained.

[0026] 200 g of catalyst 2 was placed in a fixed-bed reactor, and a mixed solution with a mass ratio of n-butanol to furfural of 3:1 was continuously fed with H 2 at a controlled reaction temperature of 100 °C and a reaction pressure of 2 Mpa. After reacting for 2 hours, the product was collected for analysis. The conversion rate of furfural was 100%, the selectivity for 1,2-pentanediol was 63%, and the selectivity for tetrahydrofurfuryl alcohol was 36.8%.

[0027] Example 3

[0028] After the 200 g support was modified with NaNO 3 it was then impregnated isovolumetrically in an aqueous mixed solution of nickel nitrate, ruthenium nitrate, and lanthanum nitrate. After drying, calcination, and reduction, a catalyst 3 with 2% Na content, 0.6% Ru content, 0.2% Ni content, 1% La content, and a specific surface area of 300 m 2 / g was obtained.

[0029] 200 g of catalyst 3 was placed in a fixed-bed reactor, and a mixed solution with a mass ratio of 1-pentanol to furfural of 5:1 was continuously fed with H 2 at a controlled reaction temperature of 160 °C and a reaction pressure of 2 Mpa. After reacting for 2 hours, the product was collected for analysis. The conversion rate of furfural was 100%, the selectivity for 1,2-pentanediol was 51.6%, and the selectivity for tetrahydrofurfuryl alcohol was 48%.

[0030] Example 4

[0031] After modifying 200 g of the support with Mg(NO 3 ) 2 and KNO 3 , the obtained modified support was impregnated isovolumetrically in an aqueous mixed solution of copper nitrate, ruthenium nitrate, and cerium nitrate. After drying, calcination, and reduction, a catalyst 4 with 1% Mg content, 4% K content, 0.7% Ru content, 0.3% Cu content, 0.05% Ce content, and a specific surface area of 250 m 2 / g was obtained.

[0032] 200 g of catalyst 4 was placed in a fixed-bed reactor. The reaction temperature was controlled at 180 °C, the reaction pressure was 3 Mpa, and a mixed solution with a mass ratio of tetrahydrofurfuryl alcohol to furfuryl alcohol of 5:1 was continuously fed with H 2 . After reacting for 2 hours, the products were collected for analysis. The conversion rate of furfuryl alcohol was 100%, the selectivity for 1,2-pentanediol was 58.1%, and the selectivity for tetrahydrofurfuryl alcohol was 41.7%. This catalyst was continuously operated for 8000 h with unchanged activity.

[0033] Example 5

[0034] After modifying 200 g of the support with Ca(NO 3 ) 2 and KNO 3 , the obtained modified support was impregnated isovolumetrically in an aqueous mixed solution of palladium chloride, nickel chloride, and lanthanum chloride. After drying, calcination, and reduction, a catalyst 5 with 0.5% Ca content, 1.5% K content, 0.6% Pd content, 0.3% Ni content, 0.1% La content, and a specific surface area of 400 m 2 / g was obtained.

[0035] 200 g of catalyst 5 was placed in a fixed-bed reactor. The reaction temperature was controlled at 150 °C, the reaction pressure was 3 Mpa, and a mixed solution with a mass ratio of isopropyl alcohol to furfuryl alcohol of 5:1 was continuously fed with H 2 . After reacting for 2 hours, the products were collected for analysis. The conversion rate of furfuryl alcohol was 100%, the selectivity for 1,2-pentanediol was 51.3%, and the selectivity for tetrahydrofurfuryl alcohol was 48.5%.

[0036] Example 6

[0037] After modifying 200 g of the support with NaNO 3 , the obtained modified support was impregnated isovolumetrically in an aqueous mixed solution of palladium chloride and lanthanum cerium nitrate. After drying, calcination, and reduction, a catalyst 6 with 2% Na content, 0.1% Pd content, 0.3% La content, 0.3% Ce content, and a specific surface area of 350 m 2 / g was obtained.

[0038] 200 g of catalyst 6 was placed in a fixed-bed reactor, and the reaction temperature was controlled at 150 °C, the reaction pressure was 2 Mpa. A mixed solution with a mass ratio of tetrahydrofurfuryl alcohol to furfural of 4:1 was fed continuously with H 2 After reacting for 2 hours, the product was collected and analyzed. The conversion rate of furfural was 100%, the selectivity of 1,2-pentanediol was 62.1%, and the selectivity of tetrahydrofurfuryl alcohol was 37.6%.

Claims

1. Application of a catalyst in the synthesis of 1,2-pentanediol, characterized in that, The catalyst uses alumina modified by alkali metal and / or alkaline earth metal salts as the carrier, and a catalyst with a specific surface area of 220-400 m 2 / g is obtained by loading transition metals and rare earth metals; the above alkali metal and / or alkaline earth metal salts are one or more of Mg(NO 3 ) 2 , Ca(NO 3 ) 2 , Ba(NO 3 ) 2 , KNO 3 , NaNO 3 ; the above transition metals are one or more of Ru, Pt, Pd, Ni, Cu; the above rare earth metals are one or more of La, Ce, Sm; the content of the alkali metal and / or alkaline earth metal accounts for 0.5-10.0% of the total weight of the catalyst; the content of the transition metal accounts for 0.1-1.0% of the total weight of the catalyst; the content of the rare earth metal accounts for 0.01-5.0% of the total weight of the catalyst; The synthesis of 1,2-pentanediol is carried out in a fixed-bed reactor. Using the said catalyst, with furfuryl alcohol, furfural or a mixture of both as raw materials, after mixing with a certain proportion of solvent, it reacts with H 2 under certain conditions. After the reaction product is separated and purified, 1,2-pentanediol product is obtained; the reaction pressure is 1.0 - 3.0 MPa, and the reaction temperature is 100 - 200 °C; the above-mentioned solvent is selected from one of water, tetrahydrofurfuryl alcohol, n-butanol, 1-pentanol, and isopropanol; the mass ratio of the solvent to the raw material is 2.0 - 5.0:

1.

2. The application according to claim 1, characterized in that, The specific surface area of the catalyst is 280 to 350 m 2 / g.

3. The application according to claim 1, characterized in that, the content of the alkali metal and / or alkaline earth metal accounts for 1.5-5.0% of the total weight of the catalyst.

4. The application according to claim 1, characterized in that, the content of the transition metal accounts for 0.4-0.8% of the total weight of the catalyst.

5. The application according to claim 1, characterized in that, the content of the rare earth metal accounts for 0.5-2.5% of the total weight of the catalyst.