A transition bimetallic catalyst wrapped by a graphenelike carbon shell and a method for preparing hydroxypropanone from catalytic hydrogenolysis of cellulose

Abstract

The application discloses a kind of graphite-like carbon shell layer wrapped transition bimetallic catalyst and the method for preparing hydroxypropanone from cellulose catalytic hydrogenolysis.The preparation method of catalyst includes the following steps: organic acid, metal salt one, metal salt two and water are mixed, stirring is carried out at 70 DEG C for 8 hours, then temperature is raised to 105 DEG C, and 8 hours of incubation is obtained Powder sample, the powder sample is calcined under the protection of Ar atmosphere at 400-800 DEG C for 3 hours, to obtain the catalyst;The metal ion of metal salt one, metal salt two is different and each is independently selected from any one of transition metal in group VIIIB.The catalyst of the application has the advantages of low price, large reserve, simple preparation method, mild condition and no need for hydrogen reduction again;Efficiently catalyze lignocellulose to be converted into hydroxypropanone product, and activity is excellent, efficiency is high, can be reused.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of catalytic hydrogenolysis of cellulose, in particular to a kind of graphite-like carbon shell layer wrapped transition bimetallic catalyst and the method for preparing hydroxypropanone from catalytic hydrogenolysis of lignocellulose. BACKGROUND

[0002] Lignocellulosic biomass is the most abundant renewable biomass resource on earth, which is mainly derived from agricultural and forestry waste and plants. It is mainly composed of cellulose (30-50%), hemicellulose (20-40%) and lignin (15-25%), in addition to a small amount of ash, lipids and structural proteins. Cellulose is a high molecular polymer formed by linear connection of glucose units through β-1, 4 glycosidic bond, and interacts with each other through hydrogen bond to form amorphous and crystalline regions. The content of components is different for different plant species.

[0003] Hydroxypropanone is a very important basic organic industrial raw material. It can be used to prepare medicines, spices, dyes, etc.; it can also be used as an organic synthesis intermediate, a solvent for nitrocellulose, and a peptide synthesis protective agent. Industrially, acetone alcohol is mainly produced from petroleum-propylene through epoxide, consuming a large amount of traditional fossil energy. With the large consumption of petroleum resources and increasing emphasis on environmental protection, the research on the preparation of fine chemicals from renewable biomass has become one of the hot topics in recent years. Biomass is abundant, widely available, renewable, and has the advantages of less pollution, so the development of fine chemicals from biomass instead of traditional petroleum has been widely valued by many countries in the world. Among them, lignocellulose has a specific stereostructure and optical structure, which can be used for directional regulation and analysis of the conversion products, reducing the occurrence of side reactions, so it has become the focus of researchers. The preparation of hydroxypropanone from biomass instead of fossil raw materials not only has the advantages of abundant raw material resources, low economic pressure, flexible process route, energy saving and emission reduction, but also can solve the increasingly serious environmental pollution problem caused by agricultural and forestry waste. SUMMARY

[0004] The main purpose of the present application is to provide a graphite-like carbon shell layer wrapped transition bimetallic catalyst capable of catalyzing hydrogenolysis of cellulose to prepare hydroxypropanone and a method for preparing hydroxypropanone from catalytic hydrogenolysis of lignocellulose.

[0005] To achieve the above-mentioned purpose, the present application provides a graphite-like carbon shell layer wrapped transition bimetallic catalyst, and the preparation method comprises the following steps:

[0006] The organic acid, the metal salt one and the metal salt two are mixed, stirred at 70 DEG C for 8 hours, then heated to 105 DEG C, and kept for 8 hours to obtain a powder sample, which is calcined at 400-800 DEG C under Ar atmosphere for 3 hours to obtain the catalyst; the metal ions of the metal salt one and the metal salt two are different and each is independently selected from any one of the transition metals in Group VIIIB.

[0007] Further, the metal ions of the metal salt one and the metal salt two are each independently selected from any one of Co, Fe, Ni, Mo, Ru and Sn.

[0008] Further, the salts of the metal salt one and the metal salt two are each independently selected from any one of nitrate, chloride, sulfate and ammonium salt.

[0009] Further, the organic acid is citric acid, and the molar ratio of the metal salt one, the metal salt two and the organic acid is 1:1:1.

[0010] The application also provides application of the above catalyst in preparation of hydroxyacetone from catalytic hydrogenolysis of lignocellulose.

[0011] The application also provides a method for preparing hydroxyacetone from catalytic hydrogenolysis of cellulose, comprising the following steps: taking cellulose as raw material, water as solvent, and performing reaction under catalysis of the above catalyst, reaction temperature is 220-260 DEG C, reaction time is 0.5-2.5 h, and hydrogen pressure in the reaction system is 2.0-6.0 MPa.

[0012] The application has the following advantages:

[0013] The transition bimetallic catalyst wrapped by the graphene-like carbon shell layer has the advantages of low price, large reserve, simple preparation method, mild conditions and no need for additional hydrogen reduction, etc.; can efficiently catalyze lignocellulose to convert into hydroxyacetone product, and has excellent activity and high efficiency, and can be reused.

[0014] Under the action of the transition bimetallic catalyst wrapped by the graphene-like carbon shell layer, cellulose can be efficiently converted into hydroxyacetone, and the catalyst has excellent activity and high efficiency in the reaction process, and has the advantages of low cost and large-scale application. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 Fig. 1 is a TEM image of the catalyst prepared in Example 1.

[0016] Figure 2 Fig. 2 is an XRD image of the catalyst obtained at different calcination temperatures.

[0017] Figure 3are XPS spectra of the catalysts obtained at different calcination temperatures. DETAILED DESCRIPTION

[0018] The application will be further described in connection with the following specific examples. Unless otherwise specified, the raw materials used in the examples of the application are commercially available or can be obtained by those skilled in the art. Unless otherwise specified, the methods used in the examples of the application are methods mastered by those skilled in the art.

[0019] wherein the cellulose is purchased from Sigma Biotechnology Co., Ltd., GR.

[0020] Example 1

[0021] Preparation of transition bimetallic catalyst wrapped by graphenelike carbon shell

[0022] In a beaker, 10 mL of deionized water, 0.03 mol of tin tetrachloride, 0.03 mol of cobalt nitrate and 0.03 mol of citric acid were added, and stirred at 70°C and a stirring rate of 230 rpm for 8 hours, and then dried by heating to 105°C for 8 hours. A powder sample was obtained, and the powder sample was heated to 600°C in an inert gas Ar atmosphere and calcined for 3 hours to obtain a transition bimetallic catalyst wrapped by a graphenelike carbon shell, denoted as Sn-Co@C catalyst.

[0023] Referring to Figure 1 The TEM image of the catalyst shows that the catalyst is in a spherical state, the shell is a carbon layer, the metal is wrapped in the carbon layer, the gap between the carbon layers is about 0.334 nm, and it is a graphenelike structure.

[0024] Example 2

[0025] Experiment of preparing hydroxyacetone by catalytic hydrogenolysis

[0026] 0.1 g of Sn-Co@C catalyst prepared in Example 1, 0.2 g of cellulose and 20 ml of water were placed into a 50 ml high-pressure reaction kettle, the kettle was sealed, the gas in the kettle was replaced with H2 for 3 times, the pressure was increased to 4.0 MPa with H2, the stirring paddle was opened (500 rpm), the reaction kettle was heated to 250°C at a heating rate of 8°C / min, and the reaction was started to be timed. The reaction time was 1 h. After the reaction was completed, the product was collected, and it was calculated that the yield of hydroxyacetone product was 50.7%.

[0027] Examples 3-15

[0028] Effect of reaction temperature and reaction time on the yield of hydroxyacetone prepared by catalytic hydrogenolysis of cellulose

[0029] On the basis of example 2, the reaction temperature and reaction time are changed, and other conditions are the same as example 2, the experiments of example 3-15 are set, the specific reaction temperature, time and experimental results are shown in table 1.

[0030] Table 1

[0031]

[0032] Examples 16-23:

[0033] The effect of the roasting temperature and the metal salt ratio on the yield of hydroxyacetone prepared by the catalytic hydrogenation of cellulose.

[0034] On the basis of example 1, the roasting and metal salt ratio are changed, and other conditions are the same as example 1, the graphene-like carbon shell wrapped transition bimetallic catalysts of example 16-23 are prepared, and then the catalytic hydrogenolysis experiments for preparing hydroxyacetone are carried out according to the method of example 2, the specific roasting temperature, metal salt ratio and experimental results are shown in table 2 below.

[0035] Table 2

[0036] Example Baking temperature (°C) Sn / Co metal usage ratio Hydroxyacetone yield (%) 16 400 1:1 23.4 17 500 1:1 40.0 18 600 1:1 50.7 19 700 1:1 42.2 20 800 1:1 36.7 21 600 2:1 21.1 22 600 3:1 28.4 23 600 4:1 33.8

[0037] Referring to Figure 2 As can be seen from the figure, different SnOx diffraction peaks and different CoSn alloy diffraction peaks corresponding to different calcination temperatures.

[0038] Referring to Figure 3 It can be seen that the metal Sn mainly exists in the form of SnOx in the catalyst. With the increase of the amount of Sn / Co, the Sn species gradually shifts to the high energy band, indicating that different types of alloys are formed between the two metals.

[0039] Examples 24-28:

[0040] Effect of catalyst cycle number on the yield of hydroxyacetone prepared by catalytic hydrogenolysis of cellulose

[0041] The experimental method of example 2 is used to recycle the catalyst, and the catalyst does not need to be hydrogenated and reduced each time. The yield of hydroxyacetone is calculated each time, the cycle number and the results are shown in table 3 below.

[0042] Table 3

[0043]

[0044]

[0045] As can be seen from the above table, the yield of hydroxyacetone is 50.7% when the catalyst of Example 24 is used for the first time (i.e. Example 2), and the catalytic effect is still good after the catalyst is used for several times. This indicates that the catalyst of the present application has a long service life.

[0046] Examples 29-38

[0047] Effect of graphene-like carbon shell coated one or two metal catalysts on the yield of hydroxyacetone prepared by catalytic hydrogenolysis of cellulose

[0048] On the basis of Example 1, the type of metal salt added is changed, and other conditions are the same as those of Example 1. Graphene-like carbon shell coated transition bimetallic catalysts of Examples 29-38 are prepared, and then experiments of preparing hydroxyacetone by catalytic hydrogenolysis are carried out according to the method of Example 2. The experimental results are shown in Table 4 below.

[0049] Table 4

[0050] Example Catalyst Hydroxyacetone yield (%) 29 Fe@C 7.9 30 Co@C 12.5 31 Ni@C 10.2 32 Mo@C 14.1 33 Ru@C 5.7 34 Sn@C 17.8 35 Fe-Co@C 13.3 36 Ni-Co@C 11.7 37 Mo-Co@C 20.9 38 Ru-Co@C 11.3

[0051] Note: The catalyst prepared by adding two kinds of metal salts is represented by general formula m-n@C, w@C represents the catalyst prepared by adding only one kind of metal salt, m is the metal ion of metal salt one, n is the metal ion of metal salt two, and w is the metal ion of one kind of metal salt.

[0052] The above description is merely preferred embodiments of the present application but not to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A process for the production of hydroxyacetone from catalytic hydrogenolysis of cellulose, characterized in that, The method comprises the following steps: taking cellulose as a raw material, taking water as a solvent, and reacting under the catalysis of a transition bimetallic catalyst wrapped by a graphenelike carbon shell layer, wherein the reaction temperature is 250 DEG C, the reaction time is 1 h, and the hydrogen pressure in the reaction system is 4.0 MPa; The preparation method of the transition bimetallic catalyst wrapped by the graphenelike carbon shell layer comprises the following steps: mixing an organic acid, a metal salt 1, a metal salt 2 and water, stirring at 70 DEG C for 8 hours, then heating to 105 DEG C, and keeping the temperature for 8 hours to obtain a powder sample, and calcining the powder sample at 600 DEG C under Ar atmosphere protection for 3 hours to obtain the catalyst; the metal salt 1 is a tin salt, and the metal salt 2 is a cobalt salt; the organic acid is citric acid, and the molar ratio of the metal salt 1, the metal salt 2 and the organic acid is 1:1:

1.

2. The process for the production of hydroxyacetone from the catalytic hydrogenolysis of cellulose according to claim 1, characterized in that, The metal salt 1 and the metal salt 2 are each independently selected from any one of nitrate, chloride, sulfate and ammonium salt.

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