Preparation method of biodiesel and application of biodiesel in preparation of biodiesel by taking waste edible oil as raw material

Abstract

The invention discloses a preparation method of biodiesel and application of the biodiesel in preparation of the biodiesel by taking waste edible oil as a raw material. The polynuclear metal catalyst is composed of an organic ligand and metal ions (titanium ions), and the method uses the catalyst with low cost and high catalytic transesterification reaction performance to catalyze alcoholysis of triglyceride, vegetable oil and animal fat in different alcohol solvents, thereby preparing the high-performance and renewable biodiesel. The invention not only provides an efficient and environment-friendly biodiesel preparation method, but also provides a new technical approach for resource utilization of the waste edible oil and fat, has important economic and social benefits, can realize high-value utilization of the waste oil and fat and reduce environmental pollution, and simultaneously promotes sustainable development of the biodiesel industry.

Description

Technical Field

[0001] The invention belongs to the field of recycling and utilizing waste edible oils to prepare renewable energy, belongs to the field of energy conservation and environmental protection, and specifically relates to a method for preparing biodiesel and its application in preparing biodiesel as a raw material. Background Art

[0002] Energy is a fundamental need in people's lives, playing a vital role in all business sectors, including transportation, power generation, agriculture, and industry. Currently, global energy relies primarily on petrochemical resources. However, fossil fuels are non-renewable energy sources, and people are increasingly aware that the rapid growth in demand for fossil fuels will lead to potential energy shortages and increased environmental pollution.

[0003] Diesel is one of the most widely used fossil fuels, widely used in long-distance transportation, agriculture, and industry. Due to its relatively high combustion efficiency and energy density, its reliability in long-term storage and emergency starting, and its use as a primary component in high-torque, long-duration engines in long-distance transportation, it has proven difficult to replace with other clean energy fuels. Biodiesel (fatty acid methyl ester), a renewable energy source, is widely considered to be a partial or complete replacement for traditional petroleum diesel due to its superior combustion properties and biodegradability, reducing dependence on fossil fuels. This alternative fuel can help reduce greenhouse gas emissions and air pollution, alleviating global climate change and environmental issues. However, biodiesel synthesis is currently a very expensive process, and high production costs are one of the major obstacles to its production and application. Furthermore, insufficient raw materials, insufficient downstream consumption, and outdated catalyst technology may also be major factors contributing to the slow development of biodiesel.

[0004] At present, scholars have done a lot of research on the preparation of biodiesel. Studies have shown that it is of great significance to select suitable and efficient catalysts for reaction and optimize the conditions and methods of alcoholysis. The main methods for preparing biodiesel at present include: physical mixing method, chemical high temperature cracking and supercritical method, ionic liquid catalysis method, bioenzyme method and other methods for preparing biodiesel. Among them, the most concentrated is the research on the use of acid / base catalysts and bioenzymes through ester exchange method in homogeneous / heterogeneous systems. Compared with homogeneous catalysts, heterogeneous catalysts have the characteristics of excellent catalytic performance, easy separation, and not easily affected by impurities such as free fatty acids and phosphoric acid in waste oils. In recent years, based on the research of heterogeneous catalysts, Lewis acid catalysts and heterogeneous acid-base bifunctional catalysts have become the most important research objects. Using Salen iron (III) acetate as a catalyst, the reaction was carried out at 180 ° C and a methanol: oil ratio of 20:1 mol / mol for 2h, and the yield of biodiesel reached 90% (Catalysis Letters, 2022, 152 (12): 3785-3794.). However, the transesterification reaction using this Lewis catalyst requires a high methanol / oil molar ratio to achieve a high biodiesel yield, which poses a significant challenge in terms of both cost and experimental safety. Using CaO-La2O3 as the catalyst, a 3-hour reaction at 160°C, a methanol:oil ratio of 25:1 mol / mol, and 3 wt% catalyst resulted in a yield of 98.76% (Journal of the American Chemical Society, 2007, 129(36): 11161-11171). This type of catalyst requires a long time to achieve high yields at high alcohol / oil molar ratios, which can lead to high costs and safety concerns.

[0005] While research on biodiesel catalysts and methods has progressed, there is still no biodiesel production method that is both cost-effective and efficient, with high yields and the ability to support large-scale production. Therefore, developing efficient, low-cost catalysts, optimizing alcoholysis conditions, and catalyzing the high-value conversion of edible oil waste to biodiesel remains a significant challenge. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the object of the present invention is to provide a method for preparing biodiesel and its application in preparing biodiesel using waste edible oil as raw material.

[0007] One of the purposes of the present invention is to provide a method for preparing biodiesel.

[0008] The method is alcoholysis of pure glyceride in different alcohol using multi-core metal catalyst; the product after alcoholysis is separated and purified to obtain biodiesel.

[0009] Preferably, the following multi-core metal catalyst is used, the multi-core metal catalyst comprises organic ligand and metal ion, the chemical formula of the multi-core metal catalyst is shown as (I) and (II); a kind of glyceride, the glyceride comprises pure glyceride and waste edible oil and other waste oil, the chemical structure general formula of the glyceride is shown as (III):

[0010]

[0011] Wherein, R1, R2, R3, R4, R5 each independently represents hydrogen, halogen, alkyl, alkoxy, halogenated alkyl, M each independently represents titanium ion (Ti 4+ ), X each independently represents coordination solvent, R6, R7, R8 each independently represents alkane chain without double bond or olefin chain containing different number of double bonds.

[0012] Preferably, R1, R2, R3, R4, R5 each independently is hydrogen, fluorine, chlorine, bromine, iodine, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, sec-pentyl, isopentyl, cyclopentyl, n-hexyl, sec-hexyl, isohexyl, methoxy, ethoxy, isopropoxy, tert-butyloxy;

[0013] Preferably, R6, R7, R8 is octadecane or olefin, containing 0-5 double bonds;

[0014] Preferably, the chemical formula of the multi-core metal catalyst is as follows:

[0015]

[0016] Preferably, the following structural formula is used:

[0017]

[0018] Preferably, the chemical formula of the glyceride is as follows:

[0019]

[0020]

[0021] Preferably, the glyceride is derived from waste edible oil, and the glyceride for alcoholysis is derived from one or more of triglyceride, soybean oil, palm oil, sesame oil, olive oil, lard, rapeseed oil and linseed oil.

[0022] Preferably, the molar ratio of the glyceride to the polynuclear metal catalyst is 1:0.005 to 1:0.04.

[0023] Preferably, the alcohol solvent is at least one of methanol, ethanol, isopropanol, ethylene glycol, 1,2-butanediol, and 1,4-butanediol.

[0024] The above-mentioned method for preparing biodiesel comprises the following steps:

[0025] A multi-nuclear metal catalyst is obtained by in-situ synthesis of organic phenol ligands and metal ion compounds. The multi-nuclear metal catalyst is used to catalyze the alcoholysis (ester exchange) of glyceride in an alcohol solvent to obtain fatty acid methyl ester (biodiesel) and glycerol. The products are separated and purified to obtain pure biodiesel.

[0026] Preferably, the alcoholysis is carried out in an alcohol solvent; the alcoholysis temperature is 120-180° C.; the alcoholysis pressure is 0-10 MPa; and the molar ratio of the glyceride to the alcohol solvent is 1:12-1:18.

[0027] A second object of the present invention is to provide an application of the method for preparing biodiesel as described in the first object of the invention in preparing biodiesel by alcoholysis of waste edible oils and fats.

[0028] Preferably, the waste edible oil for alcoholysis comes from one or more of school cafeterias, Sichuan restaurants, fast food restaurants, and Cantonese restaurants.

[0029] Preferably, the molar ratio of the waste edible oil and fat to the multi-nuclear metal catalyst is 1:0.01 to 1:0.04.

[0030] More preferably, the alcohol solvent is at least one of methanol, ethanol, isopropanol, ethylene glycol, and 1,4-butanediol.

[0031] Preferably, the glyceride is derived from waste edible oils and fats, and the source of the alcoholysed glyceride is one or more of triglycerides, soybean oil, palm oil, sesame oil, olive oil, lard, rapeseed oil, and linseed oil.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The core content of the present invention is divided into two parts: first, the preparation method of biodiesel and its application in the preparation of biodiesel using waste edible oils as raw materials. In terms of the preparation method of biodiesel, a multi-nuclear metal catalyst with high-efficiency ester exchange catalytic performance is used to catalyze the alcoholysis of pure glycerides in an alcohol solvent to prepare biodiesel at low cost, efficiently and safely. Second, an optimized biodiesel preparation method is used to alcoholyze waste edible oils and other waste oils to prepare biodiesel. This application is to use the optimal biodiesel preparation method to simply, efficiently, low-energy consumption, and low-cost alcoholyze waste edible oils and other waste oils to obtain high-yield biodiesel. This innovation not only reduces production costs, but also provides a feasible technical path for the large-scale production of biodiesel.

[0034] (1) The organic ligand raw materials of the polynuclear metal catalyst synthesized and used in the present invention are inexpensive and easy to obtain, and the preparation process is simple. The novel metal polynuclear complex catalyst can be synthesized by only performing an ester exchange reaction between the organic ligand and the metal compound.

[0035] (2) The biodiesel preparation conditions of the present invention are relatively mild, with low energy consumption and high safety, which meets the application standards of scientific research institutions and industrial fields and shows broad market application prospects.

[0036] (3) The preparation method of the present invention is applied to the preparation of biodiesel using waste edible oil as raw material, which not only provides a new direction for the large-scale preparation of biodiesel, but also alleviates the problems of large waste edible oil production and the recycling and abuse of waste edible oil, and has good industrial application value and environmental benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Preparation of biodiesel for Application Example 1 1 H NMR spectrum;

[0038] Figure 2 For the preparation of biodiesel using waste edible oil as raw material in Example 8 1 H NMR spectrum;

[0039] Figure 3 It is a reaction principle diagram of the present invention. DETAILED DESCRIPTION

[0040] For a better understanding of the present invention, the following examples are provided to further illustrate the present invention, but the content of the present invention is not limited to the following examples.

[0041] Example 1

[0042] Synthesis of Catalyst 1 and Preparation Conditions of Biodiesel 1

[0043] In a 100ml round-bottom flask, add 2g (7mmol) of tetraisopropyl titanate and a solution of 2.64g (28mmol) of phenol in n-hexane (20mL) and stir at room temperature for 2 hours. After the reaction is complete, remove all volatiles by vacuum distillation to obtain a yellow solid (3g, 89%). 1 H NMR spectrum Figure 1 . 1 H NMR (400MHz, Chloroform-d): δ7.23 (d, J=7.7Hz, 8H), 6.93 (t, J=7.4Hz, 4H), 6.84 (d, J=7.9Hz, 8H), 4.07 (p, J=6.1Hz, 1H), 1.22 (d, J=6.1Hz, 6H).

[0044] Catalyze the alcoholysis of tristearin using catalyst 1. Add 500 mg of tristearin to a 2 ml thick-walled pressure bottle, then add 2.7 mg of catalyst 1 and 3.4 ml of methanol. After alcoholysis at 160 ° C for 1 hour, the system changes from heterogeneous to homogeneous. The mother liquor is 1 H NMR characterization showed that the yield of fatty acid methyl ester (biodiesel) was above 99.9%.

[0045]

[0046] Example 2

[0047] Biodiesel Preparation Condition 2 (Catalyst 1)

[0048] Catalyst 1 was used to catalyze the alcoholysis of tristearin. 500 mg of tristearin was added to a 2 ml thick-walled pressure bottle, followed by 5.4 mg of catalyst 1 and 3.4 ml of methanol. After alcoholysis at 160 ° C for 45 minutes, the system changed from heterogeneous to homogeneous. The mother liquor was then 1 H NMR characterization showed that the yield of fatty acid methyl ester (biodiesel) was above 99.9%.

[0049] Example 3

[0050] Biodiesel Preparation Condition 3 (Catalyst 1)

[0051] Catalyst 1 was used to catalyze the alcoholysis of tristearin. 500 mg of tristearin was added to a 2 ml thick-walled pressure bottle, followed by 8.1 mg of catalyst 1 and 3.4 ml of methanol. After alcoholysis at 160 ° C for 40 minutes, the system changed from heterogeneous to homogeneous. The mother liquor was then 1 H NMR characterization showed that the yield of fatty acid methyl ester (biodiesel) was above 99.9%.

[0052] Example 4

[0053] Biodiesel Preparation Condition 4 (Catalyst 1)

[0054] Catalyst 1 was used to catalyze the alcoholysis of tristearin. 500 mg of tristearin was added to a 2 ml thick-walled pressure bottle, followed by 10.8 mg of catalyst 1 and 3.4 ml of methanol. After alcoholysis at 160 ° C for 35 minutes, the system changed from heterogeneous to homogeneous. The mother liquor was then 1 H NMR characterization showed that the yield of fatty acid methyl ester (biodiesel) was above 99.9%.

[0055] Example 5

[0056] Biodiesel Preparation Condition 5 (Catalyst 1)

[0057] Catalyze the alcoholysis of tristearin using catalyst 1. Add 500 mg of tristearin to a 2 ml thick-walled pressure bottle, then add 2.7 mg of catalyst 1 and 4.5 ml of methanol. After alcoholysis at 160 ° C for 1 hour, the system changes from heterogeneous to homogeneous. The mother liquor is 1 H NMR characterization showed that the yield of fatty acid methyl ester (biodiesel) was above 99.9%.

[0058] Example 6

[0059] Biodiesel Preparation Condition 6 (Catalyst 1)

[0060] Catalyst 1 was used to catalyze the alcoholysis of tristearin. 500 mg of tristearin was added to a 2 ml thick-walled pressure bottle, followed by 2.7 mg of catalyst 1 and 5.0 ml of ethanol. After alcoholysis at 160 ° C for 1 hour, the system was still heterogeneous. The mother liquor was then 1 H NMR characterization showed that the yield of fatty acid methyl ester (biodiesel) was about 53.4%.

[0061] Example 7

[0062] Biodiesel Preparation Condition 7 (Catalyst 1)

[0063] Catalyst 1 was used to catalyze the alcoholysis of tristearin. 500 mg of tristearin was added to a 2 ml thick-walled pressure bottle, followed by 2.7 mg of catalyst 1 and 2.4 ml of ethylene glycol. After alcoholysis at 160 ° C for 1 hour, the system was still heterogeneous. The mother liquor was then 1 H NMR characterization showed that the yield of fatty acid methyl ester (biodiesel) was about 68.6%.

[0064] Example 8

[0065] Biodiesel Preparation Conditions 8 (Catalyst 1)

[0066] Catalyst 1 was used to catalyze the alcoholysis of tristearin. 500 mg of tristearin was added to a 2 ml thick-walled pressure bottle, followed by 2.7 mg of catalyst 1 and 3.8 ml of 1,4-butanediol. After alcoholysis at 160 ° C for 1 hour, the system was still heterogeneous. The mother liquor was then 1 H NMR characterization showed that the yield of fatty acid methyl ester (biodiesel) was about 63.3%.

[0067] Example 9

[0068] Synthesis of catalyst 2 and preparation conditions of biodiesel 1

[0069] In a 100 ml round-bottom flask, add 2 g (7 mmol) of tetraisopropyl titanate and a solution of 3 g (28 mmol) of p-cresol in n-hexane (20 ml) and stir at room temperature for 2 hours. After the reaction is complete, remove all volatiles in vacuo to obtain a yellow solid (3.4 g, 92%). 1 H NMR (400MHz, Chloroform-d): δ7.06 (d, J=7.9Hz, 8H), 6.76 (d, J=7.9Hz, 8H), 4.11-4.05 (m, 1H), 2.30 (s, 12H), 1.24 (d, J=6.2Hz, 6H).

[0070]

[0071] Catalyst 2 was used to catalyze the alcoholysis of tristearin. 500 mg of tristearin was added to a 2 ml thick-walled pressure bottle, followed by 2.7 mg of catalyst 2 and 3.4 ml of methanol. After alcoholysis at 160 ° C for 1 hour, the system changed from heterogeneous to homogeneous. The mother liquor was then 1 H NMR characterization showed that the yield of fatty acid methyl ester (biodiesel) was above 99.9%.

[0072] Example 10

[0073] Biodiesel Preparation Condition 2 (Catalyst 2)

[0074] Catalyst 2 was used to catalyze the alcoholysis of tristearin. 500 mg of tristearin was added to a 2 ml thick-walled pressure bottle, followed by 5.4 mg of catalyst 2 and 3.4 ml of methanol. After alcoholysis at 160 ° C for 45 minutes, the system changed from heterogeneous to homogeneous. The mother liquor was then 1 H NMR characterization showed that the yield of fatty acid methyl ester (biodiesel) was above 99.9%.

[0075] Example 11

[0076] Biodiesel Preparation Condition 3 (Catalyst 2)

[0077] Catalyst 2 was used to catalyze the alcoholysis of tristearin. 500 mg of tristearin was added to a 2 ml thick-walled pressure bottle, followed by 8.1 mg of catalyst 2 and 3.4 ml of methanol. After alcoholysis at 160 ° C for 40 minutes, the system changed from heterogeneous to homogeneous. The mother liquor was then 1 H NMR characterization showed that the yield of fatty acid methyl ester (biodiesel) was above 99.9%.

[0078] Example 12

[0079] Biodiesel Preparation Condition 4 (Catalyst 2)

[0080] Catalyst 2 was used to catalyze the alcoholysis of tristearin. 500 mg of tristearin was added to a 2 ml thick-walled pressure bottle, followed by 10.8 mg of catalyst 2 and 3.4 ml of methanol. After alcoholysis at 160 ° C for 35 minutes, the system changed from heterogeneous to homogeneous. The mother liquor was then 1 H NMR characterization showed that the yield of fatty acid methyl ester (biodiesel) was above 99.9%.

[0081] Example 13

[0082] Biodiesel Preparation Condition 5 (Catalyst 2)

[0083] Catalyst 2 was used to catalyze the alcoholysis of tristearin. 500 mg of tristearin was added to a 2 ml thick-walled pressure bottle, followed by 2.7 mg of catalyst 2 and 4.5 ml of methanol. After alcoholysis at 160 ° C for 1 hour, the system changed from heterogeneous to homogeneous. The mother liquor was then 1 H NMR characterization showed that the yield of fatty acid methyl ester (biodiesel) was above 99.9%.

[0084] Example 14

[0085] Biodiesel Preparation Condition 6 (Catalyst 2)

[0086] Catalyst 2 was used to catalyze the alcoholysis of tristearin. 500 mg of tristearin was added to a 2 ml thick-walled pressure bottle, followed by 2.7 mg of catalyst 2 and 5.0 ml of ethanol. After alcoholysis at 160 ° C for 1 hour, the system was still heterogeneous. The mother liquor was 1 H NMR characterization showed that the yield of fatty acid methyl ester (biodiesel) was about 53.4%.

[0087] Example 15

[0088] Biodiesel Preparation Condition 7 (Catalyst 2)

[0089] Catalyst 2 was used to catalyze the alcoholysis of tristearin. 500 mg of tristearin was added to a 2 ml thick-walled pressure bottle, followed by 2.7 mg of catalyst 2 and 2.4 ml of ethylene glycol. After alcoholysis at 160 ° C for 1 hour, the system was still heterogeneous. The mother liquor was then 1 H NMR characterization showed that the yield of fatty acid methyl ester (biodiesel) was about 65.2%.

[0090] Example 16

[0091] Biodiesel Preparation Conditions 8 (Catalyst 2)

[0092] Catalyst 2 was used to catalyze the alcoholysis of tristearin. 500 mg of tristearin was added to a 2 ml thick-walled pressure bottle, followed by 2.7 mg of catalyst 2 and 3.8 ml of 1,4-butanediol. After alcoholysis at 160 ° C for 1 hour, the system was still heterogeneous. The mother liquor was then 1 H NMR characterization showed that the yield of fatty acid methyl ester (biodiesel) was about 61.2%.

[0093] Example 17

[0094] Synthesis of catalyst 3 and preparation conditions of biodiesel 1

[0095] In a 100 ml round-bottom flask, add 2 g (7 mmol) of tetraisopropyl titanate and a solution of 4.2 g (28 mmol) of p-tert-butylphenol in n-hexane (20 ml) and stir at room temperature for 2 hours. After the reaction is complete, remove all volatiles in vacuo to obtain a yellow solid (4.4 g, 90%). 1 H NMR (400MHz, Chloroform-d): δ7.37-7.19 (m, 8H), 6.85-6.73 (m, 8H), 4.06 (p, J=6.2Hz, 1H), 1.30 (s, 36H), 1.22 (d, J=6.1Hz, 6H).

[0096]

[0097] Catalyst 3 was used to catalyze the alcoholysis of tristearin. 500 mg of tristearin was added to a 2 ml thick-walled pressure bottle, followed by 2.7 mg of catalyst 1 and 3.4 ml of methanol. After alcoholysis at 160 ° C for 1 hour, the system changed from heterogeneous to homogeneous. The mother liquor was then 1 H NMR characterization showed that the yield of fatty acid methyl ester (biodiesel) was above 99.9%.

[0098] Example 18

[0099] Biodiesel Preparation Condition 2 (Catalyst 3)

[0100] Catalyst 3 was used to catalyze the alcoholysis of tristearin. 500 mg of tristearin was added to a 2 ml thick-walled pressure bottle, followed by 5.4 mg of catalyst 3 and 3.4 ml of methanol. After alcoholysis at 160 ° C for 45 minutes, the system changed from heterogeneous to homogeneous. The mother liquor was then 1 H NMR characterization showed that the yield of fatty acid methyl ester (biodiesel) was above 99.9%.

[0101] Example 19

[0102] Biodiesel Preparation Condition 3 (Catalyst 3)

[0103] Catalyst 3 was used to catalyze the alcoholysis of tristearin. 500 mg of tristearin was added to a 2 ml thick-walled pressure bottle, followed by 8.1 mg of catalyst 3 and 3.4 ml of methanol. After alcoholysis at 160 ° C for 40 minutes, the system changed from heterogeneous to homogeneous. The mother liquor was then 1 H NMR characterization showed that the yield of fatty acid methyl ester (biodiesel) was above 99.9%.

[0104] Example 20

[0105] Biodiesel Preparation Condition 4 (Catalyst 3)

[0106] Catalyst 3 was used to catalyze the alcoholysis of tristearin. 500 mg of tristearin was added to a 2 ml thick-walled pressure bottle, followed by 10.8 mg of catalyst 3 and 3.4 ml of methanol. After alcoholysis at 160 ° C for 35 minutes, the system changed from heterogeneous to homogeneous. The mother liquor was then 1 H NMR characterization showed that the yield of fatty acid methyl ester (biodiesel) was above 99.9%.

[0107] Example 21

[0108] Biodiesel Preparation Condition 5 (Catalyst 3)

[0109] Catalyst 3 was used to catalyze the alcoholysis of tristearin. 500 mg of tristearin was added to a 2 ml thick-walled pressure bottle, followed by 2.7 mg of catalyst 3 and 4.5 ml of methanol. After alcoholysis at 160 ° C for 1 hour, the system changed from heterogeneous to homogeneous. The mother liquor was then 1 H NMR characterization showed that the yield of fatty acid methyl ester (biodiesel) was above 99.9%.

[0110] Example 22

[0111] Biodiesel Preparation Condition 6 (Catalyst 3)

[0112] Tristearin was catalytically alcoholized using catalyst 3. In a 2 ml thick-walled pressure vial, 500 mg of tristearin was added, followed by 2.7 mg of catalyst 3 and 5.0 ml of ethanol. After alcoholization at 160°C for 1 hour, the system was still heterogeneous, and the mother liquor was subjected to 1 H NMR characterization, the yield of fatty acid methyl ester (biodiesel) was about 52.6%.

[0113] Example 23

[0114] Biodiesel production condition 7 (catalyst 3)

[0115] Tristearin was catalytically alcoholized using catalyst 3. In a 2 ml thick-walled pressure vial, 500 mg of tristearin was added, followed by 2.7 mg of catalyst 3 and 2.4 ml of ethylene glycol. After alcoholization at 160°C for 1 hour, the system was still heterogeneous, and the mother liquor was subjected to 1 H NMR characterization, the yield of fatty acid methyl ester (biodiesel) was about 62.9%.

[0116] Example 24

[0117] Biodiesel production condition 8 (catalyst 3)

[0118] Tristearin was catalytically alcoholized using catalyst 3. In a 2 ml thick-walled pressure vial, 500 mg of tristearin was added, followed by 2.7 mg of catalyst 3 and 3.8 ml of 1,4-butanediol. After alcoholization at 160°C for 1 hour, the system was still heterogeneous, and the mother liquor was subjected to 1 H NMR characterization, the yield of fatty acid methyl ester (biodiesel) was about 62.9%.

[0119] The following application examples use soybean oil, olive oil, lard, and waste edible oil and fat as glycerides to prepare biodiesel.

[0120] Application Example 1

[0121] Soybean oil was catalytically alcoholized using catalyst 1 synthesized in Example 1. In a 2 ml thick-walled pressure vial, 500 mg of soybean oil was added, followed by 2.7 mg of catalyst 1 and 3.4 ml of methanol. After alcoholization at 160°C for 1 hour, the system changed from heterogeneous to homogeneous, and the mother liquor was subjected to 1 H NMR( Figure 2 ) characterization, the yield of fatty acid methyl ester (biodiesel) was more than 99.9%.

[0122] Application Example 2

[0123] Catalyst 1 synthesized in Example 1 was used to catalyze the alcoholysis of palm oil. In a 2ml thick-walled pressure vial, 500mg of palm oil was added, followed by 2.7mg of catalyst 1 and 3.4ml of methanol. After alcoholysis at 160°C for 1 hour, the system changed from heterogeneous to homogeneous phase, and the mother liquor was subjected to 1 H NMR characterization, the yield of fatty acid methyl ester (biodiesel) was above 99.9%.

[0124] Example 3 was applied

[0125] Catalyst 1 synthesized in Example 1 was used to catalyze the alcoholysis of palm oil. In a 2ml thick-walled pressure vial, 500mg of palm oil was added, followed by 2.7mg of catalyst 1 and 3.4ml of methanol. After alcoholysis at 160°C for 1 hour, the system changed from heterogeneous to homogeneous phase, and the mother liquor was subjected to 1 H NMR characterization, the yield of fatty acid methyl ester (biodiesel) was above 99.9%.

[0126] Example 4 was applied

[0127] Catalyst 1 synthesized in Example 1 was used to catalyze the alcoholysis of palm oil. In a 2ml thick-walled pressure vial, 500mg of palm oil was added, followed by 2.7mg of catalyst 1 and 3.4ml of methanol. After alcoholysis at 160°C for 1 hour, the system changed from heterogeneous to homogeneous phase, and the mother liquor was subjected to 1 H NMR characterization, the yield of fatty acid methyl ester (biodiesel) was above 99.9%.

[0128] Example 5 was applied

[0129] Catalyst 1 synthesized in Example 1 was used to catalyze the alcoholysis of palm oil. In a 2ml thick-walled pressure vial, 500mg of palm oil was added, followed by 2.7mg of catalyst 1 and 3.4ml of methanol. After alcoholysis at 160°C for 1 hour, the system changed from heterogeneous to homogeneous phase, and the mother liquor was subjected to 1 H NMR characterization, the yield of fatty acid methyl ester (biodiesel) was above 99.9%.

[0130] Example 6 was applied

[0131] Catalyst 1 synthesized in Example 1 was used to catalyze the alcoholysis of palm oil. In a 2ml thick-walled pressure vial, 500mg of palm oil was added, followed by 2.7mg of catalyst 1 and 3.4ml of methanol. After alcoholysis at 160°C for 1 hour, the system changed from heterogeneous to homogeneous phase, and the mother liquor was subjected to 1 H NMR characterization, the yield of fatty acid methyl ester (biodiesel) was above 99.9%.

[0132] Example 7 was applied

[0133] Catalyst 1 synthesized in Example 1 was used to catalyze the alcoholysis of linseed oil. 500 mg of linseed oil was added to a 2 ml thick-walled pressure bottle, followed by 2.7 mg of catalyst 1 and 3.4 ml of methanol. After alcoholysis at 160°C for 1 hour, the system changed from a heterogeneous phase to a homogeneous phase. The mother liquor was then 1 H NMR characterization showed that the yield of fatty acid methyl ester (biodiesel) was above 99.9%.

[0134] Application Example 8

[0135] Catalyst 1 synthesized in Example 1 was used to catalyze the alcoholysis of waste edible oil 1 (oil used in a school cafeteria). 500 mg of waste edible oil 1 was added to a 2 ml thick-walled pressure bottle, followed by 2.7 mg of catalyst 1 and 3.4 ml of methanol. After alcoholysis at 160 ° C for 1 hour, the system changed from heterogeneous to homogeneous. The mother liquor was subjected to 1 H NMR ( Figure 3 ) characterization, the yield of fatty acid methyl ester (biodiesel) is above 99.9%.

[0136] Application Example 9

[0137] The catalyst 1 synthesized in Example 1 was used to catalyze the alcoholysis of waste edible oil 2 (oil from Sichuan restaurant swill). 500 mg of waste edible oil 1 was added to a 2 ml thick-walled pressure bottle, followed by 2.7 mg of catalyst 1 and 3.4 ml of methanol. After alcoholysis at 160 ° C for 1 hour, the system changed from heterogeneous to homogeneous. The mother liquor was subjected to 1 H NMR characterization showed that the yield of fatty acid methyl ester (biodiesel) was above 99.9%.

[0138] Application Example 10

[0139] The catalyst 1 synthesized in Example 1 was used to catalyze the alcoholysis of waste edible oil 2 (oil from the swill of a Cantonese restaurant). 500 mg of waste edible oil 2 was added to a 2 ml thick-walled pressure bottle, followed by 2.7 mg of catalyst 1 and 3.4 ml of methanol. After alcoholysis at 160 ° C for 1 hour, the system changed from a heterogeneous phase to a homogeneous phase. The mother liquor was subjected to 1 H NMR characterization showed that the yield of fatty acid methyl ester (biodiesel) was above 99.9%.

[0140] Application Example 11

[0141] Catalyst 2 synthesized in Example 9 was used to catalyze the alcoholysis of soybean oil. 500 mg of soybean oil was added to a 2 ml thick-walled pressure bottle, followed by 2.7 mg of catalyst 2 and 3.4 ml of methanol. After alcoholysis at 160 ° C for 1 hour, the system changed from heterogeneous to homogeneous. The mother liquor was 1 H NMR characterization showed that the yield of fatty acid methyl ester (biodiesel) was above 99.9%.

[0142] Application Example 12

[0143] Catalyst 2 synthesized in Example 9 was used to catalyze the alcoholysis of palm oil. 500 mg of palm oil was added into a 2 ml thick-walled pressure vessel, followed by 2.7 mg of catalyst 2 and 3.4 ml of methanol. After alcoholysis at 160 °C for 1 hour, the system changed from heterogeneous to homogeneous phase, and the mother liquor was subjected to 1 H NMR characterization, the yield of fatty acid methyl ester (biodiesel) was above 99.9%.

[0144] Application Example 13

[0145] Catalyst 2 synthesized in Example 9 was used to catalyze the alcoholysis of sesame oil. 500 mg of sesame oil was added into a 2 ml thick-walled pressure vessel, followed by 2.7 mg of catalyst 2 and 3.4 ml of methanol. After alcoholysis at 160 °C for 1 hour, the system changed from heterogeneous to homogeneous phase, and the mother liquor was subjected to 1 H NMR characterization, the yield of fatty acid methyl ester (biodiesel) was above 99.9%.

[0146] Application Example 14

[0147] Catalyst 2 synthesized in Example 9 was used to catalyze the alcoholysis of olive oil. 500 mg of olive oil was added into a 2 ml thick-walled pressure vessel, followed by 2.7 mg of catalyst 2 and 3.4 ml of methanol. After alcoholysis at 160 °C for 1 hour, the system changed from heterogeneous to homogeneous phase, and the mother liquor was subjected to 1 H NMR characterization, the yield of fatty acid methyl ester (biodiesel) was above 99.9%.

[0148] Application Example 15

[0149] Catalyst 2 synthesized in Example 9 was used to catalyze the alcoholysis of lard oil. 500 mg of lard oil was added into a 2 ml thick-walled pressure vessel, followed by 2.7 mg of catalyst 2 and 3.4 ml of methanol. After alcoholysis at 160 °C for 1 hour, the system changed from heterogeneous to homogeneous phase, and the mother liquor was subjected to 1 H NMR characterization, the yield of fatty acid methyl ester (biodiesel) was above 99.9%.

[0150] Application Example 16

[0151] Catalyst 2 synthesized in Example 9 was used to catalyze the alcoholysis of rapeseed oil. 500 mg of rapeseed oil was added into a 2 ml thick-walled pressure vessel, followed by 2.7 mg of catalyst 2 and 3.4 ml of methanol. After alcoholysis at 160 °C for 1 hour, the system changed from heterogeneous to homogeneous phase, and the mother liquor was subjected to 1 H NMR characterization, the yield of fatty acid methyl ester (biodiesel) was above 99.9%.

[0152] Application Example 17

[0153] Catalyst 2 synthesized in Example 9 was used to catalyze the alcoholysis of flaxseed oil. 500 mg of flaxseed oil was added into a 2 ml thick-walled pressure tube, followed by the addition of 2.7 mg of catalyst 2 and 3.4 ml of methanol. After alcoholysis at 160 °C for 1 hour, the system changed from heterogeneous to homogeneous phase. The mother liquor was subjected to GC-MS analysis. 1 H NMR characterization, the yield of fatty acid methyl ester (biodiesel) was above 99.9%.

[0154] Application Example 18

[0155] Catalyst 2 synthesized in Example 9 was used to catalyze the alcoholysis of waste cooking oil 1 (used in a school canteen). 500 mg of waste cooking oil 1 was added into a 2 ml thick-walled pressure tube, followed by the addition of 2.7 mg of catalyst 2 and 3.4 ml of methanol. After alcoholysis at 160 °C for 1 hour, the system changed from heterogeneous to homogeneous phase. The mother liquor was subjected to GC-MS analysis. 1 H NMR characterization, the yield of fatty acid methyl ester (biodiesel) was above 99.9%.

[0156] Application Example 19

[0157] Catalyst 2 synthesized in Example 9 was used to catalyze the alcoholysis of waste cooking oil 2 (used in a Sichuan restaurant). 500 mg of waste cooking oil 1 was added into a 2 ml thick-walled pressure tube, followed by the addition of 2.7 mg of catalyst 2 and 3.4 ml of methanol. After alcoholysis at 160 °C for 1 hour, the system changed from heterogeneous to homogeneous phase. The mother liquor was subjected to GC-MS analysis. 1 H NMR characterization, the yield of fatty acid methyl ester (biodiesel) was above 99.9%.

[0158] Application Example 20

[0159] Catalyst 2 synthesized in Example 9 was used to catalyze the alcoholysis of waste cooking oil 2 (used in a Cantonese restaurant). 500 mg of waste cooking oil 2 was added into a 2 ml thick-walled pressure tube, followed by the addition of 2.7 mg of catalyst 2 and 3.4 ml of methanol. After alcoholysis at 160 °C for 1 hour, the system changed from heterogeneous to homogeneous phase. The mother liquor was subjected to GC-MS analysis. 1 H NMR characterization, the yield of fatty acid methyl ester (biodiesel) was above 99.9%.

[0160] Application Example 21

[0161] Titanium dioxide was used to catalyze the alcoholysis of soybean oil. 500 mg of soybean oil was added into a 2 ml thick-walled pressure tube, followed by the addition of 0.4 mg of catalyst 1 and 3.4 ml of methanol. After alcoholysis at 160 °C for 45 min, the system was still heterogeneous. The mother liquor was subjected to GC-MS analysis. 1 H NMR characterization, the yield of fatty acid methyl ester (biodiesel) was about 25.1%.

[0162] Application Example 22

[0163] Titanium tetrachloride was used to catalyze the alcoholysis of soybean oil. 500 mg soybean oil was added to a 2 ml thick-walled pressure bottle, followed by 1.1 mg catalyst 1 and 3.4 ml methanol. After alcoholysis at 160 ° C for 45 minutes, the system was still heterogeneous. The mother liquor was 1 H NMR characterization showed that the yield of fatty acid methyl ester (biodiesel) was about 53.9%.

[0164] Application Example 23

[0165] Use dichlorotitaniacin to catalyze the alcoholysis of soybean oil. Add 500mg soybean oil to a 2ml thick-walled pressure bottle, then add 1.4mg catalyst 1 and 3.4ml methanol. After alcoholysis at 160℃ for 45min, the system is still heterogeneous. 1 H NMR characterization showed that the yield of fatty acid methyl ester (biodiesel) was about 58.8%.

[0166] Application Example 24

[0167] Use tetraisopropyl titanate to catalyze the alcoholysis of soybean oil. Add 500 mg of soybean oil to a 2 ml thick-walled pressure bottle, then add 1.1 mg of catalyst 1 and 3.4 ml of methanol. After alcoholysis at 160 ° C for 45 minutes, the system is still heterogeneous. 1 HNMR characterization showed that the yield of fatty acid methyl ester (biodiesel) was about 43.8%.

[0168] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0169] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing biodiesel, characterized in that: The method is to use a multi-nuclear metal catalyst to catalyze the alcoholysis of pure glycerides in different alcohols; the chemical formula of the multi-nuclear metal catalyst is shown in the following formulas (I) and (II), and the chemical structure of the glyceride is shown in Figure (III):

2. The method for preparing biodiesel according to claim 1, wherein: In the multinuclear metal catalyst, R1, R2, R3, R4, and R5 are each independently hydrogen, fluorine, chlorine, bromine, iodine, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, sec-pentyl, isopentyl, cyclopentyl, n-hexyl, sec-hexyl, isohexyl, methoxy, ethoxy, isopropoxy, or tert-butyloxy; X each independently represents coordinated methanol, ethanol, or tetrahydrofuran; R6, R7, and R8 each independently represent an alkane chain without double bonds or an alkene chain containing different numbers of double bonds; M is Ti 4+ .

3. The method for preparing biodiesel according to claim 1, wherein: The glyceride has one or more of the following chemical formulas:

4. The method for preparing biodiesel according to claim 1, wherein: The multi-nuclear metal catalyst has one or more of the following structures: Preferably:

5. The method for preparing biodiesel according to claim 1, wherein: The temperature of the alcoholysis is 120-180° C.; the pressure of the alcoholysis is 0-10 MPa.

6. The method for preparing biodiesel according to claim 1, wherein: The method also includes separating and purifying the alcoholysis product to obtain biodiesel.

7. The method for preparing biodiesel according to claim 1, wherein: The molar ratio of the glyceride to the alcohol is 1:10-1:20; The molar ratio of the glyceride to the multi-nuclear metal catalyst is 1:0.0001 to 1:0.

06.

8. The method for preparing biodiesel according to claim 1, wherein: The alcohol solvent is one or more of methanol, ethanol, n-propanol, isopropanol, ethylene glycol, 1,2-butanediol, 1,4-butanediol, pentanol, cyclohexanol, and benzyl alcohol.

9. The method for preparing biodiesel according to claim 1, wherein: The glyceride source for alcoholysis is one or more of triglyceride, soybean oil, palm oil, sesame oil, olive oil, lard, rapeseed oil and linseed oil.

10. Use of the method for preparing biodiesel according to any one of claims 1 to 9 in preparing biodiesel using waste edible oils as raw materials, characterized in that: The waste edible oil and fat comes from oil and fat used in catering.

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