A method for the direct preparation of catechol and propylene from c-type lignin

Abstract

The present application relates to a kind of by C-type lignin directly preparing catechol and propylene method.The method uses C-type lignin as reaction substrate, reaction atmosphere is hydrogen, under the action of metal / molecular sieve catalyst, catechol and propylene are prepared in one step process.The reaction process is as follows: after C-type lignin, alcohol and water are mixed with catalyst, put into pressure vessel, seal, and at room temperature, fill in hydrogen, and pressure is higher than 1.0MPa, reaction temperature is higher than 180 DEG C, reaction time is longer than 8h, catechol and propylene yield is 20%~45% and 10-29% respectively.The method reaction process is simple, target product selectivity is high, yield is high, catalyst separation process is simple, with good industrial application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for directly preparing catechol and propylene from C-type lignin, in particular to a method for preparing catechol and propylene by metal / molecular sieve catalyst catalyzed hydrogenolysis and dealkylation of C-type lignin, and belongs to the field of efficient resource utilization of renewable agricultural and forestry wastes BACKGROUND

[0002] Catechol is an important fine chemical widely used in the field of national economy. In the field of pesticides, catechol is an important intermediate of pesticides such as furan and propoxur; it can be used as a precursor to synthesize many drugs such as dehydroepiandrosterone, levodopa and propranolol; it is also an important raw material for spices such as vanillin, piperonal and safrole; in addition, it can be used to prepare p-tert-butyl catechol polymerization inhibitor, dye, antioxidant, accelerator, preservative, etc. In recent years, the demand for catechol industry in China has maintained a rapid growth trend, and the consumption reached 10,000 tons in 2005, while the domestic production capacity was only 3,000 tons, and most of the catechol was imported.

[0003] At present, catechol is mainly produced by chemical synthesis using petroleum-based chemicals as raw materials. For example, phenol is used as raw material, and is oxidized by an oxidant to form ortho- and para-catechol. However, the conversion rate of phenol in the above process is low, and the products ortho- and para-catechol are structural isomers, and their boiling points are close, so they must be separated and purified by energy-consuming rectification method; cyclohexene is used as raw material, and is oxidized by an oxidant to form 1,2-cyclohexanediol, or 1,2-cyclohexanediol is obtained by further hydrolysis of cyclohexene oxide, and then dehydrogenation is carried out to form catechol. Although the above process can overcome the problems of low conversion rate and low selectivity in the phenol hydroxylation method, the process still uses cyclohexene fossil-based chemicals, and most of the catalysts used are noble metal catalysts. The above production routes of catechol generally have technical bottlenecks such as complex reaction process and high energy consumption. Especially with the implementation of the "carbon peak and carbon neutral" policy and the continuous promotion of the "sustainable development" strategy, it is particularly important to explore a green production route of catechol that replaces the petroleum-based route.

[0004] Lignin is a crucial component of renewable biomass and the world's most abundant renewable aromatic resource. Utilizing lignin to produce high-value-added fine chemicals holds great potential. However, due to its structural complexity, the small-molecule chemicals obtained from lignin conversion are often mixtures. Furthermore, many studies on lignin depolymerization utilize the breaking of β-O-4 ether bonds in its structure. However, the classic lignin structure, in addition to ether bonds, is rich in C-C bonds with higher bond energies, leading to low lignin degradation conversion rates and low selectivity. C-type lignin (Catechyl lignin), containing a catechol etherified structure (C), differs. Its structure contains only ether bonds of the benzodioxane structure, with almost no C-C bonds. Simultaneously, the ether bonds of the benzodioxane structure are very stable under acidic conditions and will not break or condense, but can be cracked by catalytic hydrogenation. Therefore, C-type lignin is an ideal natural renewable raw material for the depolymerization of lignin to prepare aromatic chemicals. Studies have found C-type lignin in the inner epidermis of seeds from plants such as *Cleome spinosa*, *Cleome salina*, cacti, castor bean husks, *Jatropha curcas*, *C. sarcodactylis*, and *Tung oil tree*. Castor bean seed husks contain a large amount of C-type lignin (approximately 60 wt%), while the global annual production of castor beans exceeds one million tons. The seeds are inexpensive (only $0.5-$1 / kg) and are primarily used for castor oil production. The large amount of surplus castor husks is an industrial byproduct that needs further development and utilization. Domestic and international scholars have conducted research in the field of converting C-type lignin into catechols, achieving significant theoretical and citation results. For example, John Ralph's group at the University of Wisconsin extracted C-type lignin from vanilla seed husks and then used commercial catalysts Pt / C, Pd / C, and Ru / C for hydrogenation degradation, yielding an 88% catechol mixture with a 4-hydroxypropyl catechol selectivity of 89%. Subsequently, Yuriy's group at MIT used a Ni / C catalyst to reductively separate vanilla seed husks into a mixture of 4-propyl catechol and 4-propenyl catechol. In 2020, Professor Song Guoyong's team at Beijing Forestry University in China extracted C-type lignin using an acidic eutectic system with an extraction efficiency of 42%. They further used Pd / C to catalytically degrade it, obtaining a 29.6 wt% catechol mixture.

[0005] The above methods all have the following problems: First, the depolymerization products of C-type lignin are all catechol derivatives containing side chains, which cannot be removed, resulting in a much lower added value than catechol. Second, they use expensive precious metals, leading to low yields and selectivity of lignin monomers. Based on the literature review, there are currently no reports on the directed and efficient catalytic production of catechol from C-type lignin using inexpensive metals / molecular sieves as catalysts, while simultaneously producing propylene. Summary of the Invention

[0006] The significance of the present application is to overcome the challenges existing in the current direct preparation of catechol and propylene from C-type lignin, to realize the high-yield, high-selectivity and low-cost conversion of lignin to catechol and propylene through one-step reaction under relatively mild conditions, and to realize the resourceization and high-value utilization of castor shell waste.

[0007] To achieve the above-mentioned purpose, the present application realizes the technical scheme as follows: a method for directly preparing catechol and propylene from C-type lignin. After mixing C-type lignin, solvent and catalyst, the mixture is put into a pressure container, sealed and filled with hydrogen as reaction gas, the reaction temperature is higher than 180 DEG C, and the reaction time is longer than 5 hours. The mass ratio of C-type lignin, catalyst and reaction solvent is 1:(0.5-4):(10-200). After the reaction is completed, the reaction kettle is naturally cooled, depressurized and opened, and then extracted with ethyl acetate. The obtained liquid is dried by rotary evaporation, and catechol compounds are obtained, the main component of which is catechol without side chain, and the gaseous product is propylene.

[0008] (1) The C-type lignin is mainly prepared by ball milling-enzymatic extraction, or directly using biomass containing C-type lignin as raw material. According to the patent "a method for separating, purifying and degrading lignin (CN107098803B)", the C-type lignin is extracted by ball milling-enzymatic extraction.

[0009] The enzymatic C-type lignin is prepared by the following steps: first, the castor shell endocarp is removed and crushed to ultrafine particle size (particle size≥200 mesh); then the castor shell powder is added to 0.05 mol / L sodium acetate buffer solution at a mass ratio of 1:25, and 50 FPU / g of cellulose complex enzyme is added. After enzymatic hydrolysis at 50 DEG C for 48 hours, the mixture is centrifuged to separate the solid and liquid, the solid is washed with hydrochloric acid solution with pH=2 and freeze-dried. Then the freeze-dried residue is ball milled again for 5 hours at a speed of 500 rpm, and enzymatic hydrolysis is carried out again. The ball milled residue is added to 0.05 mol / L sodium acetate buffer solution at a mass ratio of 1:25, and 50 FPU / g of cellulose complex enzyme is added. After enzymatic hydrolysis at 50 DEG C for 48 hours, the mixture is centrifuged to separate the solid and liquid, the solid is washed with hydrochloric acid solution with pH=2 and freeze-dried to prepare the enzymatic C-type lignin.

[0010] (2) The reaction solvent is one of methanol, ethanol, isopropanol and water, or any proportion of several mixed.

[0011] (3) The pressure of the hydrogen gas is 1-3 MPa.

[0012] (4) The preparation method of the metal / molecular sieve catalyst is as follows:

[0013] 500 mg of molecular sieve was dispersed in 20 mL of deionized water and stirred for 4 h, then 10 mL of metal precursor (concentration of 8.5 mmol / L) was added dropwise into the molecular sieve dispersion, while in an ice water bath and continuously stirred for 0.5 h. Then 50 mL of sodium borohydride solution (concentration of 17.0 mmol / L) was added dropwise into the above mixture, the metal was reduced to metal state, and continuously stirred for 2 h. Then centrifuged and washed with deionized water and ethanol respectively for three times, and finally dried at 60℃ for 24 h. The metal loading was analyzed by inductively coupled plasma emission spectrometer. The catalyst needs to be calcined at 500℃ under nitrogen atmosphere for 6 h before use to remove the impurities in the pores of the molecular sieve. By changing the type of metal salt in the impregnating solution or the type of molecular sieve, catalysts with different metals / molecular sieves can be obtained

[0014] The metal precursor of step (2) is one or more of nickel chloride, chloropalladic acid, ruthenium chloride, and copper chloride, and the molecular sieve is HY 30 , HY 5.2 , HY 60 , HY 80 , ZSM-5 25 , ZSM-5 50 , ZSM-5 100 , ZSM-5 200 , MOR2, MOR 12 , MOR 34 , Beta 2.5 , Beta 25 , Beta 40 , MCM-22, MCM-41, and SAPO-34. Note: The subscript of the molecular sieve is the silica-alumina ratio of the molecular sieve. In addition, the preparation methods of elemental nickel, Ni / Al2O3, and Ni / SiO2 catalysts in the comparative examples are consistent with the above method. In the preparation method of elemental nickel, no carrier is added, and an equal molar amount of nickel chloride is added, and the powder elemental nickel is obtained by direct reduction with sodium borohydride; in the preparation method of Ni / Al2O3 and Ni / SiO2, an equal amount of carrier Al2O3 and SiO2 is added, and the other chemical reagents and parameters involved in the process are consistent. The present application is to prepare catechol and olefin compounds by hydrogenation depolymerization-dealkylation of lignin in a high-pressure reaction kettle under the action of metal / molecular sieve catalyst and polar solvent; wherein the catechol compounds are mainly catechol, and the gas products are mainly propylene.

[0015] Reaction principle: through the coupling of metal hydrogenation catalyst and pore molecular sieve, the C-type lignin inert aryl side chain carbon-carbon bond is innovatively broken to prepare catechol and propylene, and the reaction path is as follows Figure 2The benzodioxane linkage in C-type lignin is hydrogenolyzed to obtain 4-propenylcatechol intermediate which is easily modified under the action of metal hydrogenation catalyst; the size of the intermediate is just suitable for the size of the molecular sieve, so it enters the molecular sieve channel to contact with the B acid active site to occur carbonium rearrangement, and finally dealkylation to obtain catechol and acetone; acetone further occurs hydrogenation dehydration to obtain propylene under the action of hydrogenation metal.

[0016] The present application relates to a kind of preparation catechol and propylene directly from C-type lignin method.The method uses C-type lignin and water as reaction substrate, reaction atmosphere is hydrogen, under the action of metal / molecular sieve catalyst, catechol and propylene are prepared in one step.The reaction process is as follows: after C-type lignin, alcohol and water are mixed with catalyst, put into pressure vessel, and fill in hydrogen at room temperature, and pressure is higher than 1.0MPa, reaction temperature is higher than 180 DEG C, reaction time is longer than 8h, catechol and propylene yield is 20%~45% and 10-29% respectively.The method reaction process is simple, target product selectivity is high, yield is high, catalyst separation process is simple, with good industrial application prospect.

[0017]

[0018] The present application uses C-type lignin as reaction substrate, reaction atmosphere is hydrogen, under the action of metal / molecular sieve catalyst, catechol and propylene are prepared in one step.The reaction process is as follows: after C-type lignin, alcohol and water are mixed with catalyst, put into pressure vessel, and fill in hydrogen at room temperature, and pressure is higher than 1.0MPa, reaction temperature is higher than 180 DEG C, reaction time is longer than 8h, catechol and propylene yield is 20%~45% and 10-29% respectively.The method reaction process is simple, target product selectivity is high, yield is high, catalyst separation process is simple, with good industrial application prospect.

[0019] Compared with the existing preparation catechol method, the present application has the following advantages:

[0020] 1.The lignin raw material used in the present application is the most abundant renewable aromatic polymer resource in nature, and is castor oil industrial waste, low in cost, and obvious in resource advantage.The method for producing catechol from castor shell lignin by using industrial waste castor shell as raw material can effectively alleviate the tension of petroleum resources, is in line with sustainable development, and also co-produces propylene, an industrial bulk consumer.

[0021] 2.The best catalyst in the present application uses low-cost transition metal nickel as active hydrogenation active center, and low-cost HY molecular sieve as acidic active center; and the catalyst has the characteristics of easy preparation, high activity, easy separation, etc., realizing high activity and high selectivity of lignin catalytic depolymerization.

[0022] 3. The present invention exhibits high catalytic conversion rate of C-type lignin, mild reaction conditions, and a high selectivity of up to 99% for catechol in the liquid product, while the main gaseous product is propylene. This invention realizes a route for the directional preparation of catechol and propylene from lignin, with high added value and promising industrial application prospects.

[0023] 4. This invention provides a new approach for the high-value utilization of C-type lignin and reduces pollution caused by the processing of lignin in the castor oil industry;

[0024] 5. This invention uses transition metals as active hydrogenation centers and molecular sieves as acidic active centers. Using C-type lignin and biomass containing C-type lignin as raw materials, it selectively depolymerizes into catechol without side chains and propylene as a side-chain product through a hydrogenation-dealkylation reaction. The catechol monomer yield is as high as 49.1 mol%, and the propylene yield is as high as 29.2 mol%. Compared with existing technologies, this invention uses renewable biomass, which is also industrial waste, as raw material, and has the advantages of wide availability, low cost, and reduced environmental pollution. Attached Figure Description

[0025] Figure 1 This is a gas chromatography-mass spectrometry chromatogram of the silanized product of Example 1;

[0026] Figure 2 The mass spectrum of the product of Example 1 is shown below. Figure 2 (a) is the mass spectrum of dodecane, an internal standard with a retention time of 6.0 min; Figure 2 (b) is the mass spectrum of the product with a retention time of 7.2 min, namely catechol; Figure 2 (c) is the mass spectrum of the product with a retention time of 8.5 min, namely 4-ethylcatechol; Figure 2 (d) is the mass spectrum of the product with a retention time of 9.2 min, namely 4-n-propylcatechol;

[0027] Figure 2 (e) is the mass spectrum of the product with a retention time of 10.0 min, namely 4-propenylcatechol; Figure 2 (f) is the mass spectrum of the product with a retention time of 10.5 min, namely 6,7-dihydroxy-benzodihydropyran. Detailed Implementation

[0028] To provide a more detailed description of the present invention, several specific implementation examples are given below, but the present invention is not limited to these embodiments.

[0029] This invention applies a metal / molecular sieve catalyst to a method for preparing catechol and propylene from C-type lignin. After the reaction, the liquid product is passed through acetic acid.

[0030] After the ethyl ester extraction, and derivatization, qualitative and quantitative analysis and measurements were performed using gas chromatography-mass spectrometry and gas chromatography. The gas chromatography products were analyzed qualitatively and quantitatively using a gas chromatography with a flame ionization detector and a thermal conductivity detector.

[0031] The catechol yield and propylene yield were calculated using the following equations:

[0032]

[0033]

[0034] where n (catechol) represents the mole amount of catechol, C (C-type lignin) represents the content of the caffeol structural unit in the castor shell lignin (mmol / g), and W (C-type lignin) represents the mass of the C-type lignin.

[0035] The content of the caffeol structural unit in the castor shell lignin was obtained by quantitative carbon spectrum characterization. Specifically, 140 mg of C-type lignin, 3.12 mg of 1,3,5-trioxa hexacyclo as an internal standard, and 2 mg of chromium acetylacetone as a relaxation reagent were dissolved in 1.0 mL of deuterated dimethyl sulfoxide. The C-type lignin was signal collected on a nuclear magnetic resonance instrument in an FT mode at 100.6 MHz using an inversion-gated decoupling pulse sequence (C13IG).

[0036] The content of the C-type lignin in the biomass containing the C-type lignin was determined according to the standard method of the U.S. Energy Laboratory. Specifically, 0.3 grams of the biomass containing the C-type lignin was accurately weighed into a high-pressure resistant hydrolysis bottle, followed by the addition of 3 mL of 72% sulfuric acid with a mass concentration, and hydrolysis in a 30°C water bath for 1 h. During this period, constant stirring was performed to ensure sufficient hydrolysis. Then, 84 mL of deionized water was added, and the hydrolysis bottle was placed in a high-pressure sterilization pot, and the temperature was raised to 121°C, and the hydrolysis reaction was performed at a constant temperature for 1 h. After the reaction was completed, the hydrolysis bottle was removed after the temperature was lowered to room temperature, and then filtration was performed. The solid filter residue was placed in a 105°C oven for drying, and the mass of the filter residue was the content of the C-type lignin in the biomass.

[0037] C-type lignin is mainly prepared by ball-milling-enzymatic hydrolysis. According to the patent "A method for separating, purifying and degrading lignin (CN107098803B)", the enzymatic hydrolysis of C-type lignin is carried out by the following steps: first, the castor shell endocarp is crushed to ultra-fine particle size (particle size ≥ 200 mesh) after removing impurities; then the castor shell powder is added to 0.05 mol / L sodium acetate buffer solution according to the mass ratio of material to solution 1:25, and 50 FPU / g of cellulose composite enzyme (mixed by cellulase and hemicellulase according to the mass ratio of 1:0.5) is added. After enzymatic hydrolysis at 50°C for 48h, the mixture is centrifuged to separate the solid and liquid, and the solid is washed with hydrochloric acid solution with pH=2 and freeze-dried. Then the freeze-dried residue is ball-milled again for 5h, the grinding ball material is zirconium oxide, the diameter is 0.5cm, 0.8cm and 1.0cm, the mass ratio is 1:1:1, the mass ratio of residue to grinding ball is 1:25, and the ball-milling speed is 500rpm; and enzymatic hydrolysis is carried out again, the ball-milled residue is added to 0.05 mol / L sodium acetate buffer solution according to the mass ratio of material to solution 1:25, and 50 FPU / g of cellulose composite enzyme is added. After enzymatic hydrolysis at 50°C for 48h, the mixture is centrifuged, the solid is washed with hydrochloric acid solution with pH=2 and freeze-dried, and the enzymatic hydrolysis C-type lignin is prepared.

[0038] Example 1

[0039] (1) Ni / HY 30 Preparation of catalyst: 500mg HY 30 Molecular sieve (molecular sieve with a silicon-aluminum ratio of 30) was dispersed in 20mL deionized water and stirred for 4h, then 10mL nickel chloride (concentration of 8.5mmol / L) was added dropwise to HY 30 The dispersion was in an ice water bath, and stirring was continued for 0.5h. Then 50mL sodium borohydride solution (concentration of 17.0mmol / L) was added dropwise to the above mixture, and the metal was reduced to metal state, and stirring was continued for 2h. Then centrifugation was carried out, and deionized water and ethanol were used to wash three times respectively, and finally dried at 60°C for 24h. The Ni loading was 0.97wt% by inductively coupled plasma emission spectrometer analysis. The catalyst needs to be calcined at 500°C in nitrogen atmosphere for 6h before use to remove the impurities in the molecular sieve channels.

[0040] By changing the type of metal salt in the impregnating solution or the type of molecular sieve, catalysts with different metals / molecular sieves can be obtained. Specifically as follows: in examples 10-16, HY 5.2 , HY 60 , HY 80 , ZSM-5 200 , MOR 34 , SAPO-34, Beta 25 is replaced by HY30 (underlined numbers are Si / Al ratios), other reaction parameters, such as reagent concentrations and amounts, and preparation temperature, time, etc., are consistent with those in Example 1; in Examples 17-19, chloropalladic acid, ruthenium chloride and ferric chloride are used as metal precursors for synthesizing metal / HY catalysts, respectively 30 Catalyst, other reaction parameters, such as reagent concentrations and amounts, and preparation temperature, time, etc., are consistent with those in Example 1.

[0041] (2) Catalytic conversion reaction: in a 30 ml polytetrafluoro-lined autoclave, 50 mg of C-type lignin, 1 mL of methanol, 4 mL of water, 100 mg of Ni / HY catalyst prepared in Example 1, and 1 mL of methanol were added, respectively, and the autoclave was sealed. After the autoclave was replaced with nitrogen three times and filled with 3 MPa of H2, the reaction was stirred at 200 °C for 12 h. After the reaction was completed, 15 mL of ethyl acetate was added to the reaction system for extraction, and the ethyl acetate phase was collected and rotary evaporated to obtain the product catechol and propylene. Subsequently, 40 μL of THF, 10 μL of pyridine, and 50 μL of bis(trimethylsilyl)trifluoroacetamide were added, and the mixture was derivatized at 60 °C for 1 h. The product was detected by chromatography, and the yields of catechol and propylene are shown in Table 1. 30 Catalytic conversion reaction: in a 30 ml polytetrafluoro-lined autoclave, 50 mg of C-type lignin, 1 mL of methanol, 4 mL of water, 100 mg of Ni / HY catalyst prepared in Example 1, and 1 mL of methanol were added, respectively, and the autoclave was sealed. After the autoclave was replaced with nitrogen three times and filled with 3 MPa of H2, the reaction was stirred at 200 °C for 12 h. After the reaction was completed, 15 mL of ethyl acetate was added to the reaction system for extraction, and the ethyl acetate phase was collected and rotary evaporated to obtain the product catechol and propylene. Subsequently, 40 μL of THF, 10 μL of pyridine, and 50 μL of bis(trimethylsilyl)trifluoroacetamide were added, and the mixture was derivatized at 60 °C for 1 h. The product was detected by chromatography, and the yields of catechol and propylene are shown in Table 1.

[0042] Example 2

[0043] Catalyst preparation and catalytic conversion reaction conditions are the same as in Example 1, except that only the catalytic conversion reaction temperature is changed to 180 °C, and the yields of catechol and propylene are shown in Table 1.

[0044] Example 3

[0045] Catalyst preparation and catalytic conversion reaction conditions are the same as in Example 1, except that only the catalytic conversion reaction temperature is changed to 220 °C, and the yields of catechol and propylene are shown in Table 1.

[0046] Example 4

[0047] Catalyst preparation and catalytic conversion reaction conditions are the same as in Example 1, except that only the catalytic conversion reaction time is changed to 8 h, and the yields of catechol and propylene are shown in Table 1.

[0048] Example 5

[0049] Catalyst preparation and catalytic conversion reaction conditions are the same as in Example 1, except that only the catalytic conversion reaction time is changed to 16 h, and the yields of catechol and propylene are shown in Table 1.

[0050] Example 6

[0051] Catalyst preparation, catalytic conversion reaction conditions are same as example 1, except that only the solvent ratio of catalytic conversion reaction is changed to (3 mL methanol, 2 mL water), catechol and propylene yield are shown in Table 1.

[0052] Example 7

[0053] Catalyst preparation, catalytic conversion reaction conditions are same as example 1, except that only the solvent ratio of catalytic conversion reaction is changed to (4 mL methanol, 1 mL water), catechol and propylene yield are shown in Table 1.

[0054] Example 8

[0055] Catalyst preparation, catalytic conversion reaction conditions are same as example 1, except that only the solvent ratio is changed to (5 mL water), catechol and propylene yield are shown in Table 1.

[0056] Example 9

[0057] Catalyst preparation, catalytic conversion reaction conditions are same as example 1, except that only the solvent of catalytic conversion reaction is changed from methanol to ethanol, catechol and propylene yield are shown in Table 1.

[0058] Example 10

[0059] Catalyst preparation, catalytic conversion reaction conditions are same as example 1, except that only the Ni / HY 30 catalyst is replaced by Ni / HY 5.2 catalyst (molecular sieve with a silicon-aluminum ratio of 5.2), that is, the carrier HY 30 is replaced by HY 5.2 of equal mass in the catalyst preparation process, and the silicon-aluminum ratio in the molecular sieve is 5.2, and the Ni loading is 0.91wt% by inductively coupled plasma emission spectrometer analysis. Catechol and propylene yield are shown in Table 1.

[0060] Example 11

[0061] Catalyst preparation, catalytic conversion reaction conditions are same as example 1, except that only the Ni / HY 30 catalyst is replaced by Ni / HY 60 catalyst (molecular sieve with a silicon-aluminum ratio of 60), that is, the carrier HY 30 is replaced by HY 60 of equal mass in the catalyst preparation process, and the silicon-aluminum ratio in the molecular sieve is 60, and the Ni loading is 0.97wt% by inductively coupled plasma emission spectrometer analysis. Catechol and propylene yield are shown in Table 1.

[0062] Example 12

[0063] The catalyst preparation and catalytic conversion reaction conditions are the same as in Example 1, except that only Ni / HY 30 The catalyst is replaced by Ni / HY 80 The catalyst (molecular sieve with a silica-alumina ratio of 80), i.e. the carrier HY 30 is replaced by HY of the same mass 80 (where 80 is the silica-alumina ratio in the molecular sieve), and the Ni loading is 0.97 wt% as analyzed by inductively coupled plasma emission spectrometry. The catechol and propylene yields are shown in Table 1.

[0064] Example 13

[0065] The catalyst preparation and catalytic conversion reaction conditions are the same as in Example 1, except that only Ni / HY 30 The catalyst is replaced by Ni / ZSM-5 200 The catalyst (molecular sieve with a silica-alumina ratio of 200), i.e. the carrier HY 30 is replaced by ZSM-5 of the same mass 200 (where 200 is the silica-alumina ratio in the molecular sieve), and the Ni loading is 0.95 wt% as analyzed by inductively coupled plasma emission spectrometry. The catechol and propylene yields are shown in Table 1.

[0066] Example 14

[0067] The catalyst preparation and catalytic conversion reaction conditions are the same as in Example 1, except that only Ni / HY 30 The catalyst is replaced by Ni / MOR 34 The catalyst (molecular sieve with a silica-alumina ratio of 34), i.e. the carrier HY 30 is replaced by MOR of the same mass 34 (where 34 is the silica-alumina ratio in the molecular sieve), and the Ni loading is 0.90 wt% as analyzed by inductively coupled plasma emission spectrometry. The catechol and propylene yields are shown in Table 1.

[0068] Example 15

[0069] The catalyst preparation and catalytic conversion reaction conditions are the same as in Example 1, except that only Ni / HY 30 The catalyst is replaced by Ni / SAPO-34 (molecular sieve with a phosphorus-aluminum-silicon ratio of 1:1:0.3), i.e. the carrier HY 30 is replaced by SAPO-34 of the same mass, and the Ni loading is 0.99 wt% as analyzed by inductively coupled plasma emission spectrometry. The catechol and propylene yields are shown in Table 1.

[0070] Example 16

[0071] The catalyst preparation and catalytic conversion reaction conditions are the same as those of Example 1, except that only Ni / HY 30 The catalyst is replaced by Ni / Beta 25 The catalyst (molecular sieve with a silicon-aluminum ratio of 25) is prepared by replacing the metal salt species nickel chloride with an equimolar amount of palladium chloride during the catalyst preparation process. The Pd loading is 0.94wt% as analyzed by inductively coupled plasma emission spectrometry. The catechol and propylene yields are shown in Table 1. 30 The catalyst preparation and catalytic conversion reaction conditions are the same as those of Example 1, except that only Ni / HY 25 The catalyst (molecular sieve with a silicon-aluminum ratio of 25) is prepared by replacing the metal salt species nickel chloride with an equimolar amount of palladium chloride during the catalyst preparation process. The Pd loading is 0.94wt% as analyzed by inductively coupled plasma emission spectrometry. The catechol and propylene yields are shown in Table 1.

[0072] Example 17

[0073] The catalyst preparation and catalytic conversion reaction conditions are the same as those of Example 1, except that only Ni / HY 30 The catalyst is replaced by Pd / HY 30 The catalyst (molecular sieve with a silicon-aluminum ratio of 25) is prepared by replacing the metal salt species nickel chloride with an equimolar amount of palladium chloride during the catalyst preparation process. The Pd loading is 0.94wt% as analyzed by inductively coupled plasma emission spectrometry. The catechol and propylene yields are shown in Table 1.

[0074] Example 18

[0075] The catalyst preparation and catalytic conversion reaction conditions are the same as those of Example 1, except that only Ni / HY 30 The catalyst is replaced by Ru / HY 30 The catalyst (molecular sieve with a silicon-aluminum ratio of 25) is prepared by replacing the metal salt species nickel chloride with an equimolar amount of palladium chloride during the catalyst preparation process. The Pd loading is 0.94wt% as analyzed by inductively coupled plasma emission spectrometry. The catechol and propylene yields are shown in Table 1.

[0076] Example 19

[0077] The catalyst preparation and catalytic conversion reaction conditions are the same as those of Example 1, except that only Ni / HY 30 The catalyst is replaced by Cu / HY 30 The catalyst (molecular sieve with a silicon-aluminum ratio of 25) is prepared by replacing the metal salt species nickel chloride with an equimolar amount of palladium chloride during the catalyst preparation process. The Pd loading is 0.94wt% as analyzed by inductively coupled plasma emission spectrometry. The catechol and propylene yields are shown in Table 1.

[0078] Example 20

[0079] The catalyst preparation and catalytic conversion reaction conditions are the same as those of Example 1, except that only the enzymatic C-type lignin is replaced with castor shell, and the amount of castor shell is 100 mg. The catechol and propylene yields are shown in Table 1.

[0080] Comparative Example 1

[0081] Catalyst preparation, catalytic conversion reaction conditions were the same as Example 1, except that only Ni / HY 30 Catalyst replaced with HY in equal mass 30 Catalyst, catechol and propylene yields are shown in Table 1.

[0082] Comparative Example 2

[0083] Catalyst preparation, catalytic conversion reaction conditions were the same as Example 1, except that only Ni / HY 30 Catalyst replaced with elemental nickel catalyst in equal molar amount, catechol and propylene yields are shown in Table 1.

[0084] Comparative Example 3

[0085] Catalyst preparation, catalytic conversion reaction conditions were the same as Example 1, except that only Ni / HY 30 Catalyst replaced with Ni / Al2O3 catalyst in equal mass, catechol and propylene yields are shown in Table 1.

[0086] Comparative Example 4

[0087] Catalyst preparation, catalytic conversion reaction conditions were the same as Example 1, except that only Ni / HY 30 Catalyst replaced with Ni / SiO2 catalyst in equal mass, catechol and propylene yields are shown in Table 1.

[0088] Comparative Example 5

[0089] Catalytic conversion reaction conditions were the same as Example 1, but no catalyst was added, catechol and propylene yields are shown in Table 1.

[0090] Table 1 Evaluation results of direct preparation of catechol and propylene from C-type lignin

[0091]

[0092]

Claims

1. A process for the direct preparation of catechol and propene from C-type lignin, characterized by: Preparation of catechol and propylene by using C-type lignin as raw material, metal / molecular sieve as catalyst, alcohol or alcohol aqueous solution as reaction medium, and in the presence of hydrogen; The metal / molecular sieve is a molecular sieve loaded metal active component catalyst, wherein the metal is one or more of nickel (Ni), copper (Cu), palladium (Pd), and ruthenium (Ru). The molecular sieve is one or more of HY, ZSM-5, Beta, and SAPO.

2. The method of claim 1, wherein: The metal / molecular sieve catalyst, wherein the metal content is 0.5-3% by weight.

3. The method of claim 1, wherein: The metal / molecular sieve catalyst, wherein the metal content is 0.8-1.5% by weight.

4. The method of claim 1, wherein: The metal / molecular sieve catalyst, wherein the metal content is 0.9-1.2% by weight.

5. The method of claim 1, wherein: The reaction product catechol and propylene are obtained by extraction with ethyl acetate after the reaction.

6. The method of claim 1, wherein: The reaction is carried out in a closed pressure vessel, and the hydrogen pressure introduced into the reaction vessel is 1-3 MPa.

7. The method of claim 6, wherein: The hydrogen pressure introduced into the reaction vessel is 2-3 MPa.

8. The method of claim 6, wherein: The hydrogen pressure introduced into the reaction vessel is 2.5-3 MPa.

9. The method of claim 1, wherein: The reaction temperature is 160-300 ℃, and the reaction time is 4-20 h.

10. The method of claim 9, wherein: The reaction temperature is 180-220 ℃, and the reaction time is 8-16 h.

11. The method of claim 1, wherein: The alcohol is one or a mixture of any proportion of methanol, ethanol, and isopropanol, and the alcohol or alcohol and water mixed solution is used as the reaction medium, wherein the water content is 0-100% by volume.

12. The method of claim 11, wherein: The alcohol is one or a mixture of any proportion of methanol, ethanol, and isopropanol, and the alcohol or alcohol and water mixed solution is used as the reaction medium, wherein the water content is 20-100% by volume.

13. The method of claim 11, wherein: The alcohol is one or a mixture of any proportion of methanol, ethanol, and isopropanol, and the alcohol or alcohol and water mixed solution is used as the reaction medium, wherein the water content is 60-80% by volume.

14. The method of claim 1, wherein: The metal / molecular sieve catalyst, wherein the metal is one or both of nickel (Ni) and copper (Cu), and the molecular sieve is one or more than two of HY, ZSM-5, and SAPO-34.

15. The method of claim 1, wherein: The molecular sieve in the catalyst is one or both of HY and ZSM-5.

16. The method of claim 1, wherein: The mass ratio of C-type lignin, catalyst, and reaction solvent is 1: (0.5-4): (10-200).

17. The method of claim 1, wherein: The mass ratio of C-type lignin, catalyst, and reaction solvent is 1: (1-3): (50-200).

18. The method of claim 1, wherein: The mass ratio of C-type lignin, catalyst, and reaction solvent is 1: (1.5-2.5): (80-160).

19. The method of claim 1, wherein: The C-type lignin raw material includes biomass containing C-type lignin or C-type lignin. The C-type lignin is prepared by ball-milling and cellulose complex enzyme hydrolysis of biomass containing C-type lignin, the cellulose complex enzyme is mixed by cellulase and hemicellulase in a mass ratio of 1:(0.1-1), or the C-type lignin raw material directly uses the biomass containing C-type lignin as the raw material; The biomass containing C-type lignin includes one or two or more seed inner epidermis of Lotus japonicus, Stachys floridana, Cereus, castor shell, Jatropha curcas, stone chestnut and oil camphor tree.

20. The method of claim 19, wherein: The cellulose complex enzyme is mixed by cellulase and hemicellulase in a mass ratio of 1:0.2-0.

5.

21. The method according to claim 1 or 19, characterized in that: ， Formula 1 Formula 1 is a characteristic structural unit of C-type lignin-coffee alcohol unit.

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