CN114181729B - Method for synthesizing diesel precursor by photocatalysis of biomass platform compound - Google Patents

Abstract

The invention relates to a method for synthesizing a diesel precursor by photocatalysis of a biomass platform compound. Wherein the biomass raw materialIs a downstream product of lignocellulose, namely 2-methylfuran and 2, 5-dimethylfuran, and is directly synthesized into C-containing substances by illumination in the presence of a Pt-supported semiconductor photocatalyst and a small amount of water ₁₀ ～C ₁₂ And C ₁₅ ～C ₁₈ Diesel precursors in the carbon number range. The diesel oil precursor is directly converted into diesel oil through hydrodeoxygenation. The diesel oil consists of straight-chain and branched-chain alkanes and a small amount of cycloalkanes, and has a proper cetane number. And the quantum yield of the diesel precursor can be improved by 2.4 times at most by adding water. The reaction process for preparing the diesel oil is as follows: mixing 2-methylfuran, 2, 5-dimethylfuran or a mixture thereof, a catalyst, water and an acetonitrile solvent, putting the mixture into a pressure container, replacing the mixture with inert gas, stirring the mixture under normal temperature illumination for more than 1 hour, and separating the catalyst from a reaction system after the reaction. The unreacted starting material is recovered by primary distillation. The prepared diesel precursor can be prepared into high-quality diesel by the existing method.

Description

A method for photocatalytic synthesis of diesel precursor from biomass platform compounds

technical field

The invention relates to a method for photocatalytically synthesizing a diesel precursor with a biomass platform compound, in particular to a metal-loaded semiconductor photocatalyst and adding a small amount of water into the reaction system.

Background technique

Liquid fuels, including gasoline, diesel and aviation kerosene, are energy substances that are in great demand in daily life, and are also important energy strategic materials in my country. Diesel is a very important liquid fuel. It contains a mixture of alkanes, cycloalkanes, olefins and aromatics with a carbon chain length of C ₁₀ to C _22. It is divided into light diesel oil (180-370°C) and heavy diesel oil (350-410°C) . Diesel has a high energy density and is the power source for large vehicles, railway locomotives and ships. With my country's increasing emphasis on environmental protection and sustainable development, higher requirements are placed on the quality of diesel. At present, diesel oil is mainly prepared through petroleum refining, so its production greatly depends on petrochemical resources. Due to the shortage of oil in our country, the production of diesel oil is extremely dependent on imports. If high-quality diesel, especially special-purpose diesel, can be produced from renewable means, it will have a very large market value and strategic demand.

Biomass is the only renewable carbon-containing energy source on earth. The conversion of biomass to produce high-quality diesel oil is a very promising and commercially valuable diesel synthesis method. The first step in the conversion of cellulose and hemicellulose in biomass to diesel is to convert biomass into diesel precursors, which can be hydrodeoxygenated to obtain diesel. There are many methods for synthesizing biomass-based diesel in the world, but most of the diesel has problems such as low calorific value and high freezing point due to its single composition and high oxygen content (CN102864024A). Therefore, most of the diesel produced can only be added to diesel from petroleum sources, and there is a requirement for the highest addition ratio. The addition of traditional biodiesel often leads to a decline in the performance of raw diesel (CN1944582A). Therefore, at home and abroad, a method of preparing high-quality diesel oil from downstream products of lignocellulose, such as furfural, 5-hydroxymethylfurfural, levulinic acid, 2-methylfuran and 2,5-dimethylfuran, has been developed. Methods (Science, 2005, 308, 1446-1450). These methods generally include two steps, first carbon-carbon coupling of these biomass raw materials to obtain oxygenated compounds with carbon chain lengths in the range of diesel carbon numbers, and then using hydrodeoxygenation catalysts to hydrodeoxygenate the diesel precursors, and finally to obtain diesel fuel. The diesel has a high cetane number, low oxygen content and a large proportion of alkanes. Generally, these methods can only obtain straight-chain or branched-chain diesel precursors, and it is difficult to obtain straight-chain and branched-chain diesel precursors at the same time. To this end, we used biomass-based 2-methylfuran and 2,5-dimethylfuran as raw materials on metal-doped _{ZnIn2S4 -} based catalysts to obtain diesel Precursors and hydrogen, and diesel precursors contain both linear and branched components (CN201811411728.8). This process provides an additional input of light energy, resulting in a product with a higher energy density. However, the quantum yield of optimal catalysts for synthesizing diesel precursors still needs to be improved.

Contents of the invention

The purpose of the present invention is to improve the quantum yield of the photocatalytic conversion of biomass downstream products such as 2-methylfuran and 2,5-dimethylfuran to prepare diesel precursors, thereby improving the utilization rate of light energy and accelerating the production of diesel precursors. Generate rate. The obtained diesel precursor can be converted into high-quality diesel through existing mature technology.

The diesel involved in the invention can be catalyzed and synthesized by a metal-loaded semiconductor photocatalyst, and the quantum yield of the diesel precursor can be increased by adding a small amount of water. The specific preparation scheme is: after mixing one or both of 2-methylfuran or 2,5-dimethylfuran, metal-loaded semiconductor photocatalyst, water and acetonitrile solvent, put it into a quartz glass tube with inert gas Protected, stirred and reacted at room temperature under light, the reaction time is greater than or equal to 1 hour, the reaction product is dimerization (C ₁₀ ~C ₁₂ , containing 2 furan rings), trimerization (C ₁₅ ~C ₁₈ , Containing 3 furan rings) and a small amount of tetramerization products (C ₂₀ ~C ₂₄ , containing 4 furan rings). The liquid mixture remaining after recovering unreacted feedstock is the diesel precursor, which can be converted into high-quality diesel through hydrodeoxygenation.

Wherein the volume concentration of the 2-methylfuran or 2,5-dimethylfuran in the initial reaction system is 1-100vol%; the light source is one or more of xenon lamp, LED lamp or sunlight ; The supported metal of the metal-supported semiconductor photocatalyst is Ni, Au or Pt, and the metal loading is 0.01-5wt%; the semiconductor is Zn _x In ₂ S _3+x , CdS, TiO ₂ , N ₂ O ₅ or C ₃ N ₄ , wherein the value of x is 0.5-4; the catalyst dosage is 0.05-10 g L ^-1 .

The volume fraction of the added water in the initial reaction system is 0-10vol%.

Preferably: the volume concentration of the 2-methylfuran or 2,5-dimethylfuran in the initial reaction system is 10-100vol%; the light source is one or more than two kinds of LEDs; The supported metal of the supported semiconductor photocatalyst is Ru, Pd, Ni, Au or Pt, and the metal loading is 0.05 to 0.5 wt%; the semiconductor is Zn _x In ₂ S _3+x , CdS, TiO ₂ or N ₂ O ₅ , Wherein, the value of x is 0.5-4; the dosage of the catalyst is 0.2-5 g L ^-1 .

The volume fraction of the added water in the initial reaction system is 0.5-5 vol%.

Optimally: the volume concentration of the 2-methylfuran or 2,5-dimethylfuran in the initial reaction system is 30-80vol%; the light source is one or both of LED and sunlight; The supporting metal of the metal-supported semiconductor photocatalyst is Pt, and the metal loading is 0.08-0.2wt%; the semiconductor is Zn _x In ₂ S _3+x or TiO ₂ , wherein the value of x is 1-3; the catalyst dosage is 1-3 2g L ^-1 .

The volume fraction of the added water in the initial reaction system is 2-4 vol%.

After the reaction, the raw materials of 2-methylfuran and 2,5-dimethylfuran with low boiling point can be separated and recovered by flash evaporation, and the remaining liquid mixture with higher boiling point is the diesel precursor with a carbon number of C ₁₀ Between ~C ₁₂ and C ₁₅ ~C ₁₈ , the selectivity is greater than 97%.

Like other photocatalytic reactions, the greater the light intensity of the light source, the faster the reaction rate. Since the reaction products will be strongly adsorbed on the surface of the catalyst, the catalyst activity will decrease. Therefore preferred reaction time is 24-72h, can obtain required product with higher quantum yield like this (such as 2,5-dimethylfuran can obtain the highest apparent quantum yield of 45.6% on the preferred catalyst , suitable for industrial exploration).

Compared with the existing method for preparing diesel oil, the present invention has the following advantages:

1. The preparation of the catalyst is simple, and a wide range of semiconductor photocatalysts can be selected;

2. Low precious metal loading and less precious metal consumption.

3. A higher quantum yield of diesel precursor can be achieved by adding a small amount of water.

Description of drawings

Table 1 is the embodiment result summary table;

Fig. 1 is the gas chromatogram of embodiment 10.

Detailed ways

In order to further describe the present invention in detail, several specific implementation examples are given below. Among them, Examples 1-20 are examples of preparing diesel precursor by photocatalytic C-C coupling. The present invention is not limited to these examples.

Example 1

Preparation of ZnIn ₂ S ₄ catalyst by solvothermal method. Add ZnSO ₄ 7H ₂ O (1.0mmol, 287.6mg), InCl ₃ 4H ₂ O (2.0mmol, 576.5mg) and NaCl (211.5mg) into an Erlenmeyer flask filled with absolute ethanol, and stir magnetically at room temperature Thioacetamide (599.9 mg) was added to the above mixture after 30 min. After continuing to stir for 30 min, the mixture was transferred to a 50 ml clean Teflon-lined autoclave. After sealing, hydrothermal reaction at 160°C for 20h. After the reaction, the autoclave was naturally cooled to room temperature. The reacted solid was separated by centrifugation and washed three times with absolute ethanol (25 ml), twice with ultrapure water (25 ml), and finally once with absolute ethanol. The obtained yellow solid was dried under vacuum at 60 °C for 12 h.

In a 5mL quartz _glass reaction tube, add 0.5mL 2,5-dimethylfuran and 0.5mL acetonitrile respectively, weigh 5mg ZnIn ₂ S ₄ to catalyze the reaction, and add _0.1wt % Ru(NO)NO ₃ , replaced the reaction tube with argon gas and sealed it, irradiated with 1.8W LED (455nm) at room temperature for 12 hours, and obtained a diesel precursor after the reaction, and detected the product by chromatography to obtain a dimer (including 2 furan ring) and trimer (containing 3 furan rings). The conversion rate of 2,5-dimethylfuran is 6.0%, the production rate of diesel precursor is 0.450gg _catalyst ^-1 h ^-1 , the selectivity of diesel precursor is 100%, and the selection of branched-chain diesel precursor (see formula in claim 3) sex 37%.

Example 2

The preparation of ZnIn ₂ S ₄ is the same as in Example 1. In a 5mL quartz glass reaction tube, add 0.5mL 2,5-dimethylfuran, 0.463mL acetonitrile, 3.75vol% deionized water, weigh 5mg ZnIn ₂ S ₄ to catalyze the reaction, add relative ZnIn ₂ S ₄ mass fraction is 0.1wt% Ru(acac) ₃ , replace the reaction tube with argon gas and seal it, and irradiate with 1.8W LED (455nm) light for 12h at normal temperature. 2 furan rings) and trimer (containing 3 furan rings). The conversion rate of 2,5-dimethylfuran is 6.9%, the production rate of diesel precursor is 0.517gg _catalyst ^-1 h ^-1 , the selectivity of diesel precursor is 100%, and the selection of branched diesel precursor (see formula in claim 3) sex 35%.

Example 3

The preparation of ZnIn ₂ S ₄ is the same as in Example 1. In a 5mL quartz _glass reaction tube, add 0.5mL 2,5-dimethylfuran and 0.5mL acetonitrile respectively, weigh 5mg ZnIn ₂ S ₄ to catalyze the reaction, and add _0.1wt % Pd(acac) ₂ , replaced the reaction tube with argon gas and sealed it, irradiated with 1.8W LED (455nm) for 12 hours at room temperature, after the reaction, detected the product by chromatography, and obtained dimer (containing 2 furan rings) and three Polymer (containing 3 furan rings). The conversion rate of 2,5-dimethylfuran is 8.6%, the production rate of diesel precursor is 0.650gg _catalyst ^-1 h ^-1 , the selectivity of diesel precursor is 100%, and the selection of branched diesel precursor (see formula in claim 3) sex 38%.

Example 4

The preparation of ZnIn ₂ S ₄ is the same as in Example 1. In a 5mL quartz glass reaction tube, add 0.5mL 2,5-dimethylfuran, 0.463mL acetonitrile, 3.75vol% deionized water, weigh 5mg ZnIn ₂ S ₄ to catalyze the reaction, add relative ZnIn ₂ S ₄ Pd(acac) ₂ with a mass fraction of 0.1 wt%, replace the reaction tube with argon gas and seal it, and irradiate with 1.8W LED (455nm) at room temperature for 12 hours. 2 furan rings) and trimer (containing 3 furan rings). The conversion rate of 2,5-dimethylfuran is 12.2%, the production rate of diesel precursor is 0.917gg _catalyst ^-1 h ^-1 , the selectivity of diesel precursor is 100%, and the selection of branched diesel precursor (see formula in claim 3) sex 39%.

Example 5

The preparation of ZnIn ₂ S ₄ is the same as in Example 1. In a 5mL quartz _glass reaction tube, add 0.5mL 2,5-dimethylfuran and 0.5mL acetonitrile respectively, weigh 5mg ZnIn ₂ S ₄ to catalyze the reaction, and add _0.1wt % Ni(acac) ₂ , the reaction tube was replaced with argon gas and sealed, and irradiated with 1.8W LED (455nm) at room temperature for 12 hours. Polymer (containing 3 furan rings). The conversion rate of 2,5-dimethylfuran is 11.3%, the production rate of diesel precursor is 0.850gg _catalyst ^-1 h ^-1 , the selectivity of diesel precursor is 100%, and the selection of branched diesel precursor (see formula in claim 3) sex 39%.

Example 6

The preparation of ZnIn ₂ S ₄ is the same as in Example 1. In a 5mL quartz glass reaction tube, add 0.5mL 2,5-dimethylfuran, 0.463mL acetonitrile, 3.75vol% deionized water, weigh 5mg ZnIn ₂ S ₄ to catalyze the reaction, add relative ZnIn ₂ S ₄ mass fraction of 0.1wt% Ni(acac) ₂ , replace the reaction tube with argon gas and seal it, and irradiate with 1.8W LED (455nm) light for 12h at room temperature. 2 furan rings) and trimer (containing 3 furan rings). The conversion rate of 2,5-dimethylfuran is 16.4%, the production rate of diesel precursor is 1.23gg _catalyst ^-1 h ^-1 , the selectivity of diesel precursor is 100%, and the selection of branched diesel precursor (see formula in claim 3) sex 39%.

Example 7

The preparation of ZnIn ₂ S ₄ is the same as in Example 1. In a 5mL quartz _glass reaction tube, add 0.5mL 2,5-dimethylfuran and 0.5mL acetonitrile respectively, weigh 5mg ZnIn ₂ S ₄ to catalyze the reaction, and add _0.1wt % HAuCl ₄ , replaced the reaction tube with argon gas and sealed it, and irradiated with 1.8W LED (455nm) for 12 hours at room temperature. After the reaction, the product was detected by chromatography to obtain a dimer (containing 2 furan rings) and a trimer ( Contains 3 furan rings). The conversion rate of 2,5-dimethylfuran is 8.6%, the production rate of diesel precursor is 0.650gg _catalyst ^-1 h ^-1 , the selectivity of diesel precursor is 100%, and the selection of branched diesel precursor (see formula in claim 3) sex 37%.

Example 8

The preparation of ZnIn ₂ S ₄ is the same as in Example 1. In a 5mL quartz glass reaction tube, add 0.5mL 2,5-dimethylfuran, 0.463mL acetonitrile, 3.75vol% deionized water, weigh 5mg ZnIn ₂ S ₄ to catalyze the reaction, add relative ZnIn ₂ HAuCl ₄ with a mass fraction of S4 of 0.1 wt%, replaced the reaction tube with argon gas and sealed it, irradiated with 1.8W LED (455nm) light for 12 hours at room temperature, after the reaction was completed, the product was detected _by chromatography to obtain a dimer (containing 2 furan ring) and trimer (containing 3 furan rings). The conversion rate of 2,5-dimethylfuran is 16.8%, the production rate of diesel precursor is 1.27gg _catalyst ^-1 h ^-1 , the selectivity of diesel precursor is 100%, and the selection of branched diesel precursor (see formula in claim 3) sex 39%.

Example 9

The preparation of ZnIn ₂ S ₄ is the same as in Example 1. In a 5mL quartz _glass reaction tube, add 0.5mL 2,5-dimethylfuran and 0.5mL acetonitrile respectively, weigh 5mg ZnIn ₂ S ₄ to catalyze the reaction, and add _0.1wt % Pt(acac) ₂ , replace the reaction tube with argon gas and seal it, and irradiate with 1.8W LED (455nm) at room temperature for 12h. Polymer (containing 3 furan rings) and a small amount of tetramer (containing 4 furan rings). The conversion rate of 2,5-dimethylfuran is 13.6%, the production rate of diesel precursor is 1.02gg _catalyst ^-1 h ^-1 , the selectivity of diesel precursor is 99%, and the selection of branched diesel precursor (see formula in claim 3) sex 37%.

Example 10

The preparation of ZnIn ₂ S ₄ is the same as in Example 1. In a 5mL quartz glass reaction tube, add 0.5mL 2,5-dimethylfuran, 0.463mL acetonitrile, 3.75vol% deionized water, weigh 5mg ZnIn ₂ S ₄ to catalyze the reaction, add relative ZnIn ₂ S ₄ Pt(acac) ₂ with a mass fraction of 0.1wt%, replace the reaction tube with argon gas and seal it, and irradiate with 1.8W LED (455nm) at room temperature for 12 hours. 2 furan rings), trimer (containing 3 furan rings) and a small amount of tetramer (containing 4 furan rings). The conversion rate of 2,5-dimethylfuran is 33.3%, the production rate of diesel precursor is 2.48gg _catalyst ^-1 h ^-1 , the selectivity of diesel precursor is 99%, and the selection of branched diesel precursor (see formula in claim 3) sex 39%.

Example 11

The preparation of ZnIn ₂ S ₄ is the same as in Example 1. In a 5ml quartz glass reaction tube, add 0.5mL 2,5-dimethylfuran, 0.495mL acetonitrile, 0.5vol% deionized water, weigh 5mg ZnIn ₂ S ₄ to catalyze the reaction, add relative ZnIn ₂ S ₄ Pt(acac) ₂ with a mass fraction of 0.12wt%, replace the reaction tube with argon gas and seal it, and irradiate with 1.8W LED (455nm) light for 12h at room temperature. 2 furan rings), trimer (containing 3 furan rings) and a small amount of tetramer (containing 4 furan rings). The conversion rate of 2,5-dimethylfuran is 18.1%, the production rate of diesel precursor is 1.35gg _catalyst ^-1 h ^-1 , the selectivity of diesel precursor is 99%, and the selection of branched-chain diesel precursor (see formula in claim 3) sex 37%.

Example 12

The preparation of ZnIn ₂ S ₄ is the same as in Example 1. In a 5mL quartz glass reaction tube, add 0.5mL 2,5-dimethylfuran, 0.480mL acetonitrile, 2.0vol% deionized water, weigh 5mg ZnIn ₂ S ₄ to catalyze the reaction, add relative to ZnIn ₂ S ₄ Pt(acac) ₂ with a mass fraction of 0.12wt%, replace the reaction tube with argon gas and seal it, and irradiate with 1.8W LED (455nm) light for 12h at room temperature. 2 furan rings), trimer (containing 3 furan rings) and a small amount of tetramer (containing 4 furan rings). The conversion rate of 2,5-dimethylfuran is 25.7%, the production rate of diesel precursor is 1.92gg _catalyst ^-1 h ^-1 , the selectivity of diesel precursor is 99%, and the selection of branched diesel precursor (see formula in claim 3) sex 37%.

Example 13

The preparation of ZnIn ₂ S ₄ is the same as in Example 1. In a 5mL quartz glass reaction tube, add 0.5mL 2,5-dimethylfuran, 0.463mL acetonitrile, 3.75vol% deionized water, weigh 5mg ZnIn ₂ S ₄ to catalyze the reaction, add relative ZnIn ₂ S ₄ Pt(acac) ₂ with a mass fraction of 0.12wt%, replace the reaction tube with argon gas and seal it, and irradiate with 1.8W LED (455nm) light for 12h at room temperature. 2 furan rings), trimer (containing 3 furan rings) and a small amount of tetramer (containing 4 furan rings). The conversion rate of 2,5-dimethylfuran is 33.3%, the production rate of diesel precursor is 2.48gg _catalyst ^-1 h ^-1 , the selectivity of diesel precursor is 99%, and the selection of branched diesel precursor (see formula in claim 3) sex 39%.

Example 14

The preparation of ZnIn ₂ S ₄ is the same as in Example 1. In a 5ml quartz glass reaction tube, add 0.5mL 2,5-dimethylfuran, 0.450mL acetonitrile, 5.0vol% deionized water, weigh 5mg ZnIn ₂ S ₄ to catalyze the reaction, add relative to ZnIn ₂ S ₄ Pt(acac) ₂ with a mass fraction of 0.12wt%, replace the reaction tube with argon gas and seal it, and irradiate with 1.8W LED (455nm) light for 12h at room temperature. 2 furan rings) and trimer (containing 3 furan rings). The conversion rate of 2,5-dimethylfuran is 27.4%, the production rate of diesel precursor is 2.07gg _catalyst ^-1 h ^-1 , the selectivity of diesel precursor is 100%, and the selection of branched diesel precursor (see formula in claim 3) sex 38%.

Example 15

The preparation of ZnIn ₂ S ₄ is the same as in Example 1. In a 200ml quartz glass reaction cell, add 10mL 2,5-dimethylfuran, 19mL acetonitrile, 3.33vol% deionized water, weigh 100mg ZnIn ₂ S ₄ to catalyze the reaction, add relative to ZnIn ₂ S ₄ The mass fraction of Pt(acac) ₂ is 0.12wt%. Replace the reaction tube with argon gas and seal it, and irradiate with 13.4W LED (455nm) at room temperature for 48 hours. furan ring), trimer (containing 3 furan rings) and a small amount of tetramer (containing 4 furan rings). The conversion rate of 2,5-dimethylfuran is 48.3%, the production rate of diesel precursor is 0.892gg _catalyst ^-1 h ^-1 , the selectivity of diesel precursor is 98%, and the selection of branched diesel precursor (see the formula in claim 3) sex 39%.

Example 16

The preparation of ZnIn ₂ S ₄ is the same as in Example 1. In a 200ml quartz glass reaction cell, add 10mL 2,5-dimethylfuran, 19mL acetonitrile, 3.33vol% deionized water, weigh 100mg ZnIn ₂ S ₄ to catalyze the reaction, add relative to ZnIn ₂ S ₄ The mass fraction is 0.12wt% of Pt(acac) ₂ , replace the reaction tube with argon gas and seal it, and irradiate with 13.4W LED (455nm) light for 100h at room temperature. furan ring), trimer (containing 3 furan rings) and a small amount of tetramer (containing 4 furan rings). The conversion rate of 2,5-dimethylfuran is 73.0%, the production rate of diesel precursor is 0.634gg _catalyst ^-1 h ^-1 , the selectivity of diesel precursor is 96%, and the selection of branched diesel precursor (see formula in claim 3) sex 39%.

Example 17

Zn ₂ In ₂ S ₅ catalyst prepared by solvothermal method. Add ZnSO ₄ 7H ₂ O (1.6mmol, 460.2mg), InCl ₃ 4H ₂ O (1.6mmol, 469.1mg) and NaCl (211.5mg) into an Erlenmeyer flask filled with absolute ethanol, and stir magnetically at room temperature Thioacetamide (599.9 mg) was added to the above mixture after 30 min. After continuing to stir for 30 min, the mixture was transferred to a 50 ml clean Teflon-lined autoclave. After sealing, hydrothermal reaction at 160°C for 20h. After the reaction, the autoclave was naturally cooled to room temperature. The reacted solid was separated by centrifugation and washed three times with absolute ethanol (25 ml), twice with ultrapure water (25 ml), and finally once with absolute ethanol. The obtained yellow solid was dried under vacuum at 60 °C for 12 h.

In a 200ml quartz glass reaction cell, add 10mL 2,5-dimethylfuran, 19mL acetonitrile, 3.33vol% deionized water, weigh 100mg Zn ₂ In ₂ S ₅ to catalyze the reaction, add relative Zn ₂ The mass fraction of In ₂ S ₅ is 0.12wt% Pt(acac) ₂ , replace the reaction tube with argon gas and seal it, and irradiate with 13.4W LED (455nm) at room temperature for 48 hours. Body (containing 2 furan rings), trimer (containing 3 furan rings) and a small amount of tetramer (containing 4 furan rings). The conversion rate of 2,5-dimethylfuran is 70.7%, the production rate of diesel precursor is 1.29gg _catalyst ^-1 h ^-1 , the selectivity of diesel precursor is 97%, and the selection of branched diesel precursor (see formula in claim 3) sex 39%.

Example 18

The preparation of ZnIn ₂ S ₄ is the same as in Example 1. In a 200ml quartz glass reaction cell, add 10mL 2-methylfuran, 19mL acetonitrile, and 3.33vol% deionized water respectively, weigh 100mg ZnIn ₂ S ₄ to catalyze the reaction, add relative to ZnIn ₂ S ₄ mass fraction of 0.12wt% Pt(acac) ₂ , replace the reaction tube with argon gas and seal it, and irradiate with 13.4W LED (455nm) at room temperature for 48 hours. ) and trimer (containing 3 furan rings). The conversion rate of 2-methylfuran is 9.9%, the production rate of the diesel precursor is 0.187gg _catalyst ^-1 h ^-1 , the selectivity of the diesel precursor is 100%, and the selectivity of the branched diesel precursor (see the formula in claim 3) is 32% .

Example 19

The preparation of ZnIn ₂ S ₄ is the same as in Example 1. In a 200ml quartz glass reaction cell, add 10mL 2-methylfuran, 19mL acetonitrile, and 3.33vol% deionized water respectively, weigh 100mg ZnIn ₂ S ₄ to catalyze the reaction, add relative to ZnIn ₂ S ₄ mass fraction of 0.12wt% Pt(acac) ₂ , replace the reaction tube with argon gas and seal it, and irradiate with 13.4W LED (455nm) light for 100h at normal temperature. After the reaction, the product is detected by chromatography to obtain a dimer (containing 2 furan rings ) and trimer (containing 3 furan rings). The conversion rate of 2-methylfuran is 18.8%, the production rate of diesel precursor is 0.171gg _catalyst ^-1 h ^-1 , the selectivity of diesel precursor is 100%, and the selectivity of branched diesel precursor (see formula in claim 3) is 33% .

Example 20

The preparation of ZnIn ₂ S ₄ is the same as in Example 1. In a 200ml quartz glass reaction cell, add 5mL 2-methylfuran, 15mL 2,5-dimethylfuran, 4.5mL acetonitrile, 2.0vol% deionized water, weigh 100mg ZnIn ₂ S ₄ to catalyze the reaction , add Pt(acac) ₂ with a mass fraction of 0.12wt% relative to ZnIn ₂ S ₄ , replace the reaction tube with argon gas and seal it, and irradiate with 13.4W LED (455nm) light for 100h at room temperature. After the reaction, the product is detected by chromatography , a dimer (containing 2 furan rings), a trimer (containing 3 furan rings) and a small amount of tetramer (containing 4 furan rings) were obtained. 15.3% co-conversion of 2,5-dimethylfuran and 2-methylfuran, diesel precursor production rate of 0.275gg _catalyst ^-1 h ^-1 , diesel precursor selectivity 99%, branched-chain diesel precursor (see entitlement Requirement 3 formula) selectivity 37%.

Example 21

In a 200ml quartz glass reaction cell, respectively add 10mL 2,5-dimethylfuran, 19mL acetonitrile, 3.33vol% deionized water, weigh 100mg TiO ₂ (commercial Degussa P25) to catalyze the reaction, add relative TiO ₂ Pt(acac) ₂ with a mass fraction of 0.3wt%, replaced the reaction tube with argon gas and sealed it, and irradiated it with 2.7W LED (365nm) at room temperature for 48 hours. After the reaction was completed, the product was detected by chromatography to obtain dimers (containing 2 furan rings), trimer (containing 3 furan rings) and a small amount of tetramer (containing 4 furan rings). The conversion rate of 2,5-dimethylfuran is 31.5%, the production rate of diesel precursor is 0.571gg _catalyst ^-1 h ^-1 , the selectivity of diesel precursor is 96%, and the selection of branched diesel precursor (see the formula in claim 3) sex 42%.

Example 22

In a 200ml quartz glass reaction cell, add 10mL 2,5-dimethylfuran, 19mL acetonitrile, 3.33vol% deionized water, weigh 100mg of commercial Nb ₂ O ₅ to catalyze the reaction, add relative to Nb ₂ O ₅ Pt(acac) ₂ with a mass fraction of 0.3wt%, replaced the reaction tube with argon gas and sealed it, and irradiated it with 2.7W LED (365nm) at room temperature for 48 hours. After the reaction was completed, the product was detected by chromatography to obtain a dimer (containing 2 furan rings), trimer (containing 3 furan rings) and a small amount of tetramer (containing 4 furan rings). The conversion rate of 2,5-dimethylfuran is 23.5%, the production rate of diesel precursor is 0.429gg _catalyst ^-1 h ^-1 , the selectivity of diesel precursor is 97%, and the selection of branched diesel precursor (see formula in claim 3) sex 40%.

Example 23

Cd(NO ₃ ) ₂ ·4H ₂ O (16.2mmol) and thiourea (48.6mmol) were added to a 130ml clean Teflon-lined autoclave containing ethylenediamine (80ml). After stirring for 30 min, the autoclave was sealed and reacted at 160 °C for 24 h. After the reaction, the reactor was naturally cooled to room temperature. Washed three times with absolute ethanol (25 ml) and ultrapure water (25 ml), respectively, and the obtained orange solid was vacuum-dried at 60° C. for 12 h.

In a 200ml quartz glass reaction cell, add 10mL 2,5-dimethylfuran, 19mL acetonitrile, 3.33vol% deionized water, weigh 100mg CdS to catalyze the reaction, and add 0.3wt% Pt(acac) ₂ , replace the reaction tube with argon gas and seal it, and irradiate it with 13.4W LED (365nm) for 48 hours at room temperature. Polymer (containing 3 furan rings) and a small amount of tetramer (containing 4 furan rings). The conversion rate of 2,5-dimethylfuran is 18.1%, the production rate of diesel precursor is 0.342gg _catalyst ^-1 h ^-1 , the selectivity of diesel precursor is 96%, and the selection of branched diesel precursor (see formula in claim 3) sex 39%.

Example 24

Melamine (5.0 g) was placed in a quartz boat which was then wrapped in two layers with aluminum foil. Then bake the quartz boat filled with melamine at 550°C for 4h in the air flow (heating rate 2.3°C min ^-1 ), to obtain yellow gC ₃ N ₄ . In a 200ml quartz glass reaction cell, add 10mL 2,5-dimethylfuran, 19mL acetonitrile, 3.33vol% deionized water, weigh 100mg C ₃ N ₄ to catalyze the reaction, add relative to C ₃ N ₄ The mass fraction is 0.3wt% Pt(acac) ₂ , replace the reaction tube with argon gas and seal it, and irradiate with 13.4W LED (365nm) at room temperature for 48 hours. 2 furan rings), trimer (containing 3 furan rings) and a small amount of tetramer (containing 4 furan rings). The conversion rate of 2,5-dimethylfuran is 5.9%, the production rate of diesel precursor is 0.110gg _catalyst ^-1 h ^-1 , the selectivity of diesel precursor is 99%, and the selection of branched diesel precursor (see formula in claim 3) sex 38%.

Comparative example 1: take Ag/CdS-2wt% as catalyst

The preparation of CdS is the same as in Example 23. In a 5mL quartz glass reaction tube, add 0.5mL 2,5-dimethylfuran, 0.463mL acetonitrile, and 3.75vol% deionized water, weigh 5mg CdS to catalyze the reaction, and add 0.3wt% of AgNO ₃ , replace the reaction tube with argon gas and seal it, and irradiate with 1.8W LED (455nm) at room temperature for 12 hours. 3 furan rings). The conversion rate of 2,5-dimethylfuran is 0.66%, the production rate of diesel precursor is 0.050gg _catalyst ^-1 h ^-1 , the selectivity of diesel precursor is 100%, and the selection of branched diesel precursor (see formula in claim 3) sex 32%.

Comparative Example 2: Using Pt/In ₂ S ₃ -0.12wt% as catalyst

Add InCl ₃ ·4H ₂ O (2.67mmol, 781.8mg) and NaCl (217.2mg) into a conical flask filled with absolute ethanol, stir magnetically at room temperature for 30min, then add TAA (599.9mg) to the above mixture. After continuing to stir for 30 min, the mixture was transferred to a 50 ml clean Teflon-lined autoclave. After sealing, hydrothermal reaction at 160°C for 20h. After the reaction, the autoclave was naturally cooled to room temperature. The reacted solid was separated by centrifugation and washed three times with absolute ethanol (25 ml), twice with ultrapure water (25 ml), and finally once with absolute ethanol. The obtained orange solid was dried under vacuum at 60 °C for 12 h.

In a 5mL quartz glass reaction tube, add 0.5mL 2,5-dimethylfuran and 0.5mL acetonitrile respectively, weigh 5mg In ₂ S ₃ to catalyze the reaction, and add 0.12wt% Pt(acac) ₂ , replace the reaction tube with argon gas and seal it, and irradiate 1.8W LED (455nm) at room temperature for 12 hours. After the reaction, the product is detected by chromatography to obtain a dimer (containing 2 furan rings) and a trimer (containing 3 furan rings). furan ring). The conversion rate of 2,5-dimethylfuran is 1.8%, the production rate of diesel precursor is 0.133gg _catalyst ^-1 h ^-1 , the selectivity of diesel precursor is 100%, and the selection of branched diesel precursor (see formula in claim 3) sex 35%.

Table 1. Example result summary table

Example result description:

1. By comparing examples 2,4,6,8 and 10, it can be seen that Pt is the optimal load metal;

2. By comparing Examples 9 and 10, it can be seen that the conversion rate of raw material (2,5-dimethylfuran) and the production rate of diesel precursor all increase after adding water;

3. By comparing Examples 9, 11 to 14, it can be seen that as the water content increases, the conversion rate of raw material (2,5-dimethylfuran) increases the production rate of diesel precursor;

4. By comparing Examples 14 and 15, it can be seen that although the longer the reaction time, the conversion rate of the raw material (2,5-dimethylfuran) is higher, but the production rate of the diesel precursor is lower; therefore, the raw material system is 10mL And for the reaction condition of LED (455nm) with the light source irradiating power of 13.4W, the reaction time is optimal between 48-72h. Generally speaking, the smaller the volume of the raw material, the greater the irradiation power of the light source, and the higher the conversion rate of the raw material at the same time; but the smaller the volume of the raw material, the lower the production rate of the diesel precursor, so the irradiation power of the light source and the volume of the raw material are approximately large. Higher raw material conversion rate and diesel precursor production rate can be obtained within the same reaction time;

5. By comparing Examples 15, 17 and 21-24, it can be seen that Pt/Zn ₂ In ₂ S ₅ -0.12wt% is the optimal catalyst;

6. By comparing Example 16 and Example 19, it can be seen that when 2,5-dimethylfuran is used as a substrate, the reaction rate and the diesel precursor production rate are higher;

7. Comparative Example 1 shows that even if C ₃ N ₄ semiconductors are used, Ag loading is used, and the production rate of diesel precursor is low;

8. Comparative example 2 shows that even if Pt semiconductor is used, but no water is added, and no better catalyst is used, the production rate of diesel precursor is still low.

Claims (11)

1. A method for photocatalytic synthesis of diesel precursor by biomass platform compound is characterized in that:

the method comprises the following steps:

adding one or two of 2-methylfuran or 2, 5-dimethylfuran into a pressure vessel, adding a metal-loaded semiconductor photocatalyst, water and an acetonitrile solvent, and adding inert gasReplacing gas in the system by using a gas in a sexual atmosphere, and then performing illumination stirring reaction at normal temperature for 48-72 hours to obtain a diesel precursor; wherein the load metal is one or more of Ru, pd, ni, au or Pt, and the mass fraction range of the load metal is 0.01 to 5wt% of the semiconductor carrier; the semiconductor carrier is Zn _x In ₂ S _3+x 、CdS、TiO ₂ 、Nb ₂ O ₅ Or C ₃ N ₄ One or more than two of (1) and (4), wherein the value of x is 1 to 4; filtering out the catalyst after reaction, distilling and recovering unreacted raw materials under reduced pressure, wherein the residual liquid is a diesel precursor, and the volume fraction of water in an initial reaction system is 2-4 vol%;

the reaction formula is as follows:

wherein the reaction substrate is one or two of 2-methylfuran or 2, 5-dimethylfuran, and R ¹ And R ² Not H at the same time.

2. The method of claim 1, wherein: water and noble metal are added in the reaction to promote one or two of 2-methylfuran and 2, 5-dimethylfuran to be converted into diesel oil precursor.

3. The method of claim 1, wherein:

the total volume concentration of the 2-methylfuran and/or the 2, 5-dimethylfuran in the initial reaction system is 1 to 99 vol%; the dosage of the metal-loaded semiconductor photocatalyst is 0.05 to 10g L ^-1 。

4. A method according to claim 1 or 3, characterized in that:

the metal of the metal-loaded semiconductor photocatalyst is one or more of Ni, au or Pt, the metal loading is 0.05 to 0.5wt percent of the semiconductor carrier, and the semiconductor carrier is Zn _x In ₂ S _3+x 、CdS、TiO ₂ Or Nb ₂ O ₅ One or more than two of the components, and the using amount of the catalyst is 0.2 to 5g L ^-1 The reaction system of (1).

5. The method of claim 1, wherein:

the light source is one or more of xenon lamp, high-pressure mercury lamp, LED lamp or sunlight.

6. The method of claim 1, wherein:

the solvent for photocatalytic conversion of 2-methylfuran and 2, 5-dimethylfuran into the diesel precursor is one or more of acetonitrile, acetone, 1, 4-dioxane and tetrahydrofuran.

7. The method of claim 1, wherein:

the inert atmosphere gas is Ar or N _２ One or two of them.

8. The method of claim 3, wherein:

the total volume concentration of the 2-methylfuran and/or the 2, 5-dimethylfuran in the initial reaction system is 10 to 99 vol%.

9. The method of claim 8, wherein:

the total volume concentration of the 2-methylfuran and/or the 2, 5-dimethylfuran in the initial reaction system is 30 to 80 vol%.

10. The method of claim 4, wherein:

the metal loaded semiconductor photocatalyst is Pt, the metal loading is 0.08 to 0.2wt percent of the semiconductor carrier, and the semiconductor carrier is Zn _x In ₂ S _3+x And TiO 2 ₂ Wherein the value of x is 1 to 3; the dosage of the catalyst is 1 to 2g L ^-1 The reaction system of (1).

11. The method of claim 6, wherein:

the light source is one or two of a xenon lamp or an LED.

Images