Application of eutectic solvent in synthesis of diglyceride and monoglyceride

Abstract

The invention discloses an application of a deep-eutectic solvent in synthesis of diglyceride and monoglyceride. The deep-eutectic solvent is prepared from choline chloride, metal chloride and glycerol in a molar ratio of (1-2): (1-2): (3-10). The eutectic solvent can be used as a catalyst to catalyze grease to synthesize diglyceride and monoglyceride, and has the advantages of high catalytic efficiency, high product yield and high stability.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil modification, and more specifically, the present invention relates to a method for synthesizing diglycerides and monoglycerides by using a low eutectic solvent. Background Art

[0002] Emulsifiers are substances that can significantly reduce the surface tension between two immiscible liquids (such as oil and water), thereby promoting the formation of a stable emulsion. Emulsifiers play a vital role in many industries such as food, cosmetics, and medicine. According to the form of emulsifiers in the emulsion and the role they play, they can be divided into many types, mainly including anionic, cationic, nonionic and zwitterionic emulsifiers.

[0003] As new nonionic emulsifiers, diglyceride and monoglyceride have similar structures. The molecular structure of diglyceride contains two hydrophobic fatty acid groups and one hydrophilic hydroxyl group, and the molecular structure of monoglyceride contains one hydrophobic fatty acid group and two hydrophilic hydroxyl groups. Therefore, both have strong lipophilicity and certain hydrophilicity. The unique molecular structure gives diglyceride and monoglyceride physical properties such as emulsification, lubrication, and antistatic properties. They are widely used in food, medicine and other fields.

[0004] The methods for synthesizing diglycerides and monoglycerides mainly include biological methods and chemical methods. The biological method is to use biocatalysts such as microorganisms or enzymes to produce emulsifiers. This method has the advantages of environmental protection, high efficiency, and sustainability, and has received more and more attention in recent years. However, the enzymatic preparation process is difficult to meet industrial production due to high cost, difficult to control conditions, and side reactions. The chemical method usually uses acid or alkali as a catalyst to catalyze the esterification reaction to synthesize diglycerides and monoglycerides. In comparison, the synthesis cost is lower and industrial production has been achieved, but it is still difficult to meet the new requirements for emulsifier production technology. Therefore, finding a green and safe chemical process to replace traditional technology is the current technical bottleneck for the chemical synthesis of emulsifiers diglycerides and monoglycerides.

[0005] As a kind of "environmentally friendly" solvent with great development prospects, deep eutectic solvents are composed of small molecule metabolites in organisms, such as choline derivatives, alcohol compounds, sugars, urea and other natural substances. They show significant advantages of high safety, biodegradability and complete atomic utilization, and have shown great application potential and broad prospects in the field of chemical industry. At present, there are some reports on the use of deep eutectic solvents to prepare diglycerides and monoglycerides, but they are all combined with enzymes to carry out catalytic reactions, with enzymes as catalysts and deep eutectic solvents as co-substrates or catalytic media. There are no reports on the use of deep eutectic solvents as catalysts to catalyze the synthesis of diglycerides and monoglycerides.

[0006] As a new type of solvent with high customizability, it will be of great significance to functionally design a low eutectic solvent that can be used as a catalyst for the synthesis of diglycerides and monoglycerides. Summary of the invention

[0007] Based on this, the purpose of the present invention is to provide an application of a low eutectic solvent in the synthesis of diglycerides and monoglycerides. The present invention designs a special low eutectic solvent that can efficiently catalyze the synthesis of diglycerides and monoglycerides from oils and fats.

[0008] The specific technical solutions for achieving the above-mentioned invention objectives include the following.

[0009] A first aspect of the present invention provides an application of a low eutectic solvent in the synthesis of diglycerides and monoglycerides, wherein the low eutectic solvent is prepared from choline chloride, a metal chloride and glycerol in a molar ratio of 1-2:1-2:3-10.

[0010] The second aspect of the present invention provides a method for synthesizing diglycerides and monoglycerides, comprising the following steps:

[0011] (1) heating choline chloride, metal chloride and glycerol in a molar ratio of 1-2:1-2:3-10 in a water bath until a transparent liquid solvent is formed to obtain a deep eutectic solvent;

[0012] (2) Mixing the low eutectic solvent of step (1) with oil, stirring and reacting in an oil bath, centrifuging and molecularly distilling to obtain diglycerides and monoglycerides.

[0013] Based on the design experience of low eutectic solvents, the inventors of the present invention found after a large number of experiments that a low eutectic solvent prepared with choline chloride (as a hydrogen bond donor), metal chlorides (zinc chloride, aluminum chloride, ferric chloride, as catalysts) and glycerol (as a hydrogen bond acceptor) as raw materials can be used as a catalyst to catalyze the synthesis of diglycerides and monoglycerides from oils and fats, with high catalytic efficiency, high product yield and high stability.

[0014] The low eutectic solvent component of the present invention is environmentally friendly and has the advantages of being difficult to volatilize. The catalytic reaction system can be recycled in multiple batches, and has better economy and environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The schematic diagram of the present invention is the process of using a low eutectic solvent to catalyze the preparation of diglycerides and monoglycerides from oils and fats.

[0016] Figure 2 It is the HPLC chart of the product in Example 1 of the present invention. DETAILED DESCRIPTION

[0017] In order to facilitate the understanding of the present invention, the present invention will be described more fully below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0018] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used in the present invention includes any and all combinations of one or more of the related listed items.

[0019] Unless otherwise specified, the examples are all based on conventional experimental conditions or the conditions recommended by the manufacturer's instructions. The raw materials and reagents used in the present invention are all commercially available, and any biological germplasm material can be provided to the outside for scientific research.

[0020] In some embodiments of the present invention, a use of a low eutectic solvent in the synthesis of diglycerides and monoglycerides is disclosed. The low eutectic solvent is prepared from choline chloride, a metal chloride and glycerol in a molar ratio of 1-2:1-2:3-10.

[0021] In some embodiments, the molar ratio of choline chloride, metal chloride and glycerol is 1-2:1-2:5-10.

[0022] In some embodiments, the molar ratio of choline chloride, metal chloride and glycerol is 1-2:1-2:8-10, more preferably 1:2:8-10.

[0023] In some embodiments, the metal chloride is zinc chloride, iron chloride or aluminum chloride.

[0024] In other embodiments of the present invention, a method for synthesizing diglycerides and monoglycerides is disclosed. Figure 1 , including the following steps:

[0025] (1) heating choline chloride, metal chloride and glycerol in a molar ratio of 1-2:1-2:3-10 in a water bath until a transparent liquid solvent is formed to obtain a deep eutectic solvent;

[0026] (2) Mixing the low eutectic solvent of step (1) with oil, stirring and reacting in an oil bath, centrifuging and molecularly distilling to obtain diglycerides and monoglycerides.

[0027] In some embodiments, the molar ratio of choline chloride, metal chloride and glycerol in step (1) is 1-2:1-2:3-10; preferably 1-2:1-2:8-10; more preferably 1:1:8-10.

[0028] In some embodiments, the metal chloride in step (1) is zinc chloride, ferric chloride or aluminum chloride.

[0029] In some embodiments, the temperature of the water bath in step (1) is 80°C to 100°C; and / or the temperature of the oil bath in step (2) is 140°C to 180°C; and the time of the oil bath is 10 min to 30 min.

[0030] In some embodiments, the oil in step (2) is coconut oil, lard, palm oil, soybean oil, peanut oil, or camellia oil.

[0031] In some embodiments, the weight ratio of the low eutectic solvent to the oil in step (2) is 1-2:8-9.

[0032] In the following examples, coconut oil, lard, palm oil, soybean oil, peanut oil, and camellia oil are all commercially available; choline chloride, glycerol, zinc chloride, potassium carbonate, betaine, aluminum chloride, and ferric chloride are all purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0033] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] Example 1 Synthesis of diglycerides and monoglycerides

[0035] This embodiment provides a method for synthesizing diglycerides and monoglycerides, comprising the following steps:

[0036] 1. Heat choline chloride, ferric chloride and glycerol in a molar ratio of 2:1:8 in a 100°C water bath until a transparent liquid solvent is formed;

[0037] 2. Take 20g of the low eutectic solvent and place it in different reactors with 80g of coconut oil, lard, palm oil, soybean oil, peanut oil and camellia oil respectively;

[0038] 3. Place in 160℃ oil bath and stir for 20min to stop the reaction;

[0039] 4. Centrifugal separation, further molecular distillation, HPLC detection and analysis, calculation of the catalytic synthesis efficiency and yield of diglyceride / monoglyceride.

[0040] The HPLC spectrum of the product synthesized in this example is shown in Figure 2 .from Figure 2It can be seen that the product components after the catalytic system reaction are mainly diglycerides and monoglycerides, and no by-product free fatty acids are produced.

[0041] Example 2 Synthesis of diglycerides and monoglycerides

[0042] This embodiment provides a method for synthesizing diglycerides and monoglycerides, comprising the following steps:

[0043] 1. Heat choline chloride, ferric chloride and glycerol in a molar ratio of 1:1:5 in a 100°C water bath until a transparent liquid solvent is formed;

[0044] 2. Take 20g of the low eutectic solvent and place it in different reactors with 80g of coconut oil, lard, palm oil, soybean oil, peanut oil and camellia oil respectively;

[0045] 3. Place in 160℃ oil bath and stir for 30min to stop the reaction;

[0046] 4. Centrifugal separation, further molecular distillation, HPLC detection and analysis, calculation of the catalytic synthesis efficiency and yield of diglyceride / monoglyceride.

[0047] Example 3 Synthesis of diglycerides and monoglycerides

[0048] This embodiment provides a method for synthesizing diglycerides and monoglycerides, comprising the following steps:

[0049] 1. Heat choline chloride, aluminum chloride and glycerol in a molar ratio of 1:2:5 in a 100°C water bath until a transparent liquid solvent is formed;

[0050] 2. Take 20g of the low eutectic solvent and place it in different reactors with 80g of coconut oil, lard, palm oil, soybean oil, peanut oil and camellia oil respectively;

[0051] 3. Place in 160℃ oil bath and stir for 30min to stop the reaction;

[0052] 4. Centrifugal separation, further molecular distillation, HPLC detection and analysis, calculation of the catalytic synthesis efficiency and yield of diglyceride / monoglyceride.

[0053] Example 4 Synthesis of diglycerides and monoglycerides

[0054] This embodiment provides a method for synthesizing diglycerides and monoglycerides, comprising the following steps:

[0055] 1. Heat choline chloride, zinc chloride and glycerol in a molar ratio of 2:1:8 in a 100°C water bath until a transparent liquid solvent is formed;

[0056] 2. Take 20g of the low eutectic solvent and place it in different reactors with 80g of coconut oil, lard, palm oil, soybean oil, peanut oil and camellia oil respectively;

[0057] 3. Place in 140℃ oil bath and stir for 30min to stop the reaction;

[0058] 4. Centrifugal separation, further molecular distillation, HPLC detection and analysis, calculation of the catalytic synthesis efficiency and yield of diglyceride / monoglyceride.

[0059] Example 5 Synthesis of diglycerides and monoglycerides

[0060] This embodiment provides a method for synthesizing diglycerides and monoglycerides, comprising the following steps:

[0061] 1. Heat choline chloride, zinc chloride and glycerol in a molar ratio of 1:2:10 in a 100°C water bath until a transparent liquid solvent is formed;

[0062] 2. Take 20g of the low eutectic solvent and place it in different reactors with 80g of coconut oil, lard, palm oil, soybean oil, peanut oil and camellia oil respectively;

[0063] 3. Place in 160℃ oil bath and stir for 20min to stop the reaction;

[0064] 4. Centrifugal separation, further molecular distillation, HPLC detection and analysis, calculation of the catalytic synthesis efficiency and yield of diglyceride / monoglyceride.

[0065] Example 6 Synthesis of diglycerides and monoglycerides

[0066] This embodiment provides a method for synthesizing diglycerides and monoglycerides, comprising the following steps:

[0067] 1. Heat choline chloride, zinc chloride and glycerol in a molar ratio of 1:2:8 in a 100°C water bath until a transparent liquid solvent is formed;

[0068] 2. Take 20g of the low eutectic solvent and place it in different reactors with 80g of coconut oil, lard, palm oil, soybean oil, peanut oil and camellia oil respectively;

[0069] 3. Place in 180℃ oil bath and stir for 10min to stop the reaction;

[0070] 4. Centrifugal separation, further molecular distillation, HPLC detection and analysis, calculation of the catalytic synthesis efficiency and yield of diglyceride / monoglyceride.

[0071] Comparative Example 1

[0072] The synthesis method of diglyceride and monoglyceride provided in this comparative example is the same as that of Example 6, except that a low eutectic solvent is prepared by using betaine, zinc chloride and glycerol in a molar ratio of 2:1:5.

[0073] Comparative Example 2

[0074] The synthesis method of diglyceride and monoglyceride provided in this comparative example is the same as that of Example 6, except that a low eutectic solvent is prepared by using betaine, ferric chloride and glycerol in a molar ratio of 1:1:10.

[0075] Comparative Example 3

[0076] The synthesis method of diglyceride and monoglyceride provided in this comparative example is the same as that of Example 6, except that a low eutectic solvent is prepared by using betaine, aluminum chloride and glycerol in a molar ratio of 1:1:3.

[0077] Comparative Example 4

[0078] The synthesis method of diglyceride and monoglyceride provided in this comparative example is the same as that of Example 6, except that a low eutectic solvent is prepared by using betaine, zinc chloride and glycerol in a molar ratio of 1:1:5.

[0079] Comparative Example 5

[0080] This comparative example provides a method for synthesizing diglycerides and monoglycerides, comprising the following steps:

[0081] 1. 80 g of coconut oil, lard, palm oil, soybean oil, peanut oil, and camellia oil were mixed with 20 g of a low eutectic solvent prepared by choline chloride and glycerol (molar ratio 1:2) in different reactors, and then 50 g of tert-butanol was added to each reactor as an auxiliary agent;

[0082] 2. Add 5 g of lipase CALB, stir the mixture in an oil bath at 60°C for 24 h, and centrifuge to obtain the supernatant, which is a mixture of diglycerides and monoglycerides containing emulsifiers.

[0083] Comparative Example 6

[0084] This comparative example provides a method for synthesizing diglycerides and monoglycerides, comprising the following steps:

[0085] 1. Mix 80 g of coconut oil, lard, palm oil, soybean oil, peanut oil, camellia oil and 22.1 g of glycerol in different reactors respectively;

[0086] 2. Add 4.2 g of choline chloride and 8.2 g of zinc chloride in sequence to make the molar ratio of choline chloride: zinc chloride: glycerol 1:2:8, stir the mixture in an oil bath at 150°C for 30 min, and stop the reaction;

[0087] 3. Centrifugal separation, further molecular distillation, HPLC detection and analysis, calculation of the catalytic synthesis efficiency and yield of diglyceride / monoglyceride.

[0088] Comparative Example 7

[0089] This comparative example provides a method for synthesizing diglycerides and monoglycerides, comprising the following steps:

[0090] 1. Mix 80 g of coconut oil, lard, palm oil, soybean oil, peanut oil, camellia oil and 22.1 g of glycerol in different reactors respectively;

[0091] 2. Add 4.2 g of choline chloride and 8.0 g of aluminum chloride in sequence to make the molar ratio of choline chloride: aluminum chloride: glycerol 1:2:8, stir the mixture in an oil bath at 150°C for 30 min, and stop the reaction;

[0092] 3. Centrifugal separation, further molecular distillation, HPLC detection and analysis, calculation of the catalytic synthesis efficiency and yield of diglyceride / monoglyceride.

[0093] Comparative Example 8

[0094] This comparative example provides a method for synthesizing diglycerides and monoglycerides, comprising the following steps:

[0095] 1. Mix 80 g of coconut oil, lard, palm oil, soybean oil, peanut oil, camellia oil and 22.1 g of glycerol in different reactors respectively;

[0096] 2. Add 4.2 g of choline chloride and 9.7 g of ferric chloride in sequence to make the molar ratio of choline chloride: ferric chloride: glycerol 1:2:8. Stir the mixture in an oil bath at 150°C for 30 min and stop the reaction.

[0097] 3. Centrifugal separation, further molecular distillation, HPLC detection and analysis, calculation of the catalytic synthesis efficiency and yield of diglyceride / monoglyceride.

[0098] Comparative Example 9

[0099] This comparative example provides a method for synthesizing diglycerides and monoglycerides, comprising the following steps:

[0100] 1. Mix 80g of coconut oil, lard, palm oil, soybean oil, peanut oil, camellia oil and 20g of glycerol in different reactors respectively;

[0101] 2. Add 10g zinc chloride, stir the mixture in an oil bath at 150℃ for 30min, and stop the reaction;

[0102] 3. Centrifugal separation, further molecular distillation, HPLC detection and analysis, calculation of the catalytic synthesis efficiency and yield of diglyceride / monoglyceride.

[0103] Comparative Example 10

[0104] This comparative example provides a method for synthesizing diglycerides and monoglycerides, comprising the following steps:

[0105] 1. Mix 80g of coconut oil, lard, palm oil, soybean oil, peanut oil, camellia oil and 20g of glycerol in different reactors respectively;

[0106] 2. Add 10 g of ferric chloride, stir the mixture in an oil bath at 150°C for 30 min, and stop the reaction;

[0107] 3. Centrifugal separation, further molecular distillation, HPLC detection and analysis, calculation of the catalytic synthesis efficiency and yield of diglyceride / monoglyceride.

[0108] Comparative Example 11

[0109] This comparative example provides a method for synthesizing diglycerides and monoglycerides, comprising the following steps:

[0110] 1. Mix 80g of coconut oil, lard, palm oil, soybean oil, peanut oil, camellia oil and 20g of glycerol in different reactors respectively;

[0111] 2. Add 10 g of aluminum chloride, stir the mixture in an oil bath at 150°C for 30 min, and stop the reaction;

[0112] 3. Centrifugal separation, further molecular distillation, HPLC detection and analysis, calculation of the catalytic synthesis efficiency and yield of diglyceride / monoglyceride.

[0113] The catalytic efficiency and product yield of diglycerides and monoglycerides in Examples 1 to 6 and Comparative Examples 1 to 11 were analyzed, and statistics were made on whether the solvents can be used in batches. The results are shown in Tables 1 to 3, respectively.

[0114] Table 1

[0115]

[0116] Table 2

[0117]

[0118]

[0119] Table 3

[0120]

[0121] As can be seen from Tables 1 to 3, the low eutectic solvent prepared by choline chloride, metal chloride (zinc chloride, ferric chloride or aluminum chloride) and glycerol can be used as a catalyst to catalyze the synthesis of emulsifiers diglycerides and monoglycerides from animal and vegetable oils and fats, and has substrate universality, high catalytic efficiency, high product yield, and the catalytic system can be used in batches, which improves the use efficiency of the low eutectic solvent, effectively reduces the impact on the environment, and the production is more in line with the green theme (Examples 1 to 6).

[0122] Compared with Examples 1 to 6, when the low eutectic solvent prepared by betaine, metal chloride (zinc chloride, ferric chloride or aluminum chloride) and glycerol is used to catalyze the synthesis of emulsifiers diglycerol and monoglyceride of animal and vegetable oils, the catalytic efficiency and product yield are significantly reduced, and the catalytic system cannot be used in batches (Comparative Examples 1 to 4). This is probably because the low eutectic solvent prepared by choline chloride, metal chloride (zinc chloride, ferric chloride or aluminum chloride) and glycerol is a liquid solvent, which can be fully contacted with the substrate during the catalytic process and has good catalytic performance; while the low eutectic solvent prepared by betaine, metal chloride (zinc chloride, ferric chloride or aluminum chloride) and glycerol is a solid or semi-solid system, which is not in sufficient contact with the substrate, and the catalytic efficiency and product yield will be significantly reduced.

[0123] Comparative Example 5 uses a low eutectic solvent combined with an enzyme method to synthesize diglycerides and monoglycerides. Since the preparation process is accompanied by a hydrolysis side reaction, a large amount of free fatty acids will be produced as the reaction proceeds. Therefore, the efficiency of synthesizing diglycerides and monoglycerides is very low.

[0124] Comparative Examples 6 to 8 use choline chloride, metal chlorides (zinc chloride, aluminum chloride and ferric chloride) and glycerol as a mixture (non-deep eutectic solvent), and Comparative Examples 9 to 11 use metal chlorides (zinc chloride, aluminum chloride and ferric chloride) and glycerol as a mixture (non-deep eutectic solvent) to catalyze the synthesis of emulsifiers diglycerides and monoglycerides from animal and vegetable oils. The catalytic efficiency is relatively low. The main reason may be that the catalytic metal chloride exists as solid particles, and its catalytic efficiency is limited, resulting in a very low product yield, and the system cannot be used in batches.

[0125] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0126] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. Use of a low eutectic solvent in the synthesis of diglycerides and monoglycerides, wherein the low eutectic solvent is prepared from choline chloride, metal chloride and glycerol in a molar ratio of 1-2:1-2:3-10.

2. The use according to claim 1, characterized in that: The molar ratio of the choline chloride, the metal chloride and the glycerol is 1-2:1-2:5-10.

3. The use according to claim 2, characterized in that: The molar ratio of the choline chloride, the metal chloride and the glycerol is 1-2:1-2:8-10, more preferably 1:2:8-10.

4. The use according to claim 1, characterized in that: The metal chloride is zinc chloride, ferric chloride or aluminum chloride.

5. A method for synthesizing diglycerides and monoglycerides, characterized in that: The following steps are involved: (1) heating choline chloride, metal chloride and glycerol in a molar ratio of 1-2:1-2:3-10 in a water bath until a transparent liquid solvent is formed to obtain a deep eutectic solvent; (2) Mixing the low eutectic solvent of step (1) with oil, stirring and reacting in an oil bath, centrifuging and molecularly distilling to obtain diglycerides and monoglycerides.

6. The synthesis method according to claim 5, characterized in that The molar ratio of choline chloride, metal chloride and glycerol in step (1) is 1-2:1-2:3-10; preferably 1-2:1-2:8-10; more preferably 1:1:8-10.

7. The synthesis method according to claim 5, characterized in that The metal chloride in step (1) is zinc chloride, ferric chloride or aluminum chloride.

8. The synthesis method according to claim 5, characterized in that The temperature of the water bath in step (1) is 80°C to 100°C; and / or the temperature of the oil bath in step (2) is 140°C to 180°C; the time of the oil bath is 10 min to 30 min.

9. The synthesis method according to claim 5, characterized in that The oil in step (2) is coconut oil, lard, palm oil, soybean oil, peanut oil or camellia oil.

10. The synthesis method according to claim 5, characterized in that: The weight ratio of the low eutectic solvent to the oil in step (2) is 1-2:8-9.

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