Preparation process and flow of fatty glyceride

Abstract

The present invention relates to the technical field of glyceride preparation, and discloses a fatty glyceride preparation process, which comprises the following substances: 10-100 parts of glycerol, 20-55 parts of dimethyl carbonate, and 1-50 parts of a catalyst, the catalyst is prepared from the following substances: 1 to 30 parts of cerium nitrate solution, 1 to 30 parts of LiNO3 and 1 to 30 parts of citric acid ethanol solution. The Li-CeO2 catalysts with different Li doping amounts are synthesized through a one-pot method by taking citric acid as a gelling agent, and the catalysts are used for catalyzing glyceride exchange to synthesize glycerol carbonate. A series of characterization of the catalyst shows that Li can be doped into crystal lattices of CeO2 to form [Li + O-] alkaline sites, so that the glycerol conversion rate reaches 90.16%, and the glycerol carbonate yield reaches 90.04%. After the catalyst is repeatedly used for five times, the yield of glycerol carbonate is only reduced by 7.98%, which shows that the active components are not easy to lose.

Description

Technical Field

[0001] The invention relates to the technical field of glyceride preparation, and in particular to a preparation process and flow of fatty acid glyceride. Background Art

[0002] In recent years, as biodiesel is regarded as a substitute for fossil fuels, its industry has developed rapidly, resulting in an increase in the production of byproduct glycerol year by year. Converting glycerol into high value-added products is a very meaningful task. In recent years, there have been studies on converting glycerol into glycerol carbonate. The high boiling point, high flash point and low volatility of glycerol carbonate make it a potential organic solvent, and because it contains carbonyl and hydroxyl groups, it can be used as an important chemical intermediate.

[0003] Aiming at the problems of complex catalyst preparation method and easy loss of active components in the ester exchange method for preparing glyceryl carbonate from glycerol, a preparation process and flow of fatty acid glyceride is proposed. Summary of the invention

[0004] The present invention provides a preparation process and flow of fatty acid glyceride, which solves the problems raised by the above background technology.

[0005] The present invention provides the following technical scheme: a process for preparing fatty acid glyceride, comprising the following material components: 10-100 parts of glycerol, 20-55 parts of dimethyl carbonate, and 1-50 parts of a catalyst; The catalyst comprises the following substances: 1-30 parts of cerium nitrate solution, 1-30 parts of LiNO3, and 1-30 parts of citric acid ethanol solution.

[0006] A process for preparing fatty acid glyceride comprises the following steps: S1: Add glycerol and dimethyl carbonate into a 50 mL single-necked flask; S2: Then, a catalyst is added and the reaction is carried out by heating under reflux conditions; S3: After cooling to room temperature, centrifuge to separate the catalyst, and take the supernatant as the product; In step S1, the mass ratio of glycerol to dimethyl carbonate is 1:2; In step S2, the optimal heating reaction condition for preparing glycerol carbonate by transesterification of glycerol and dimethyl carbonate is a temperature of 100°C; In step S2, the heating reaction time is 2.0 h, and the amount of catalyst used is 1% of the mass of glycerol.

[0007] Preferably, the specific preparation method of the catalyst is as follows: S1: Add 50 mL of cerium nitrate solution (0.5 mol / L) to a 250 mL flask, add LiNO3, and after the solid is completely dissolved, add 50 mL of citric acid ethanol solution (0.5 mol / L) to control the molar ratio of citric acid to cerium atoms; S2: The solution was heated at 90°C to evaporate the solvent, forming a pale yellow gel, which was dried in an oven at 100°C overnight to obtain a foamy substance; S3: Grind the obtained foamy substance, put it into a crucible, heat it to 200℃ at 1℃ / min for 3h, and then heat it to 600℃ at 5℃ / min for 2h to obtain Li-doped CeO 2 Catalyst, denoted as xLi-CeO 2 , where x is the molar ratio of Li to Ce; S4: CeO2 was prepared by the same method without adding LiNO3.

[0008] Preferably, in step S3, the molar ratio of Li to Ce is 0.3:1.

[0009] The present invention has the following beneficial effects: 1. The preparation process of fatty acid glyceride is to synthesize Li-CeO with different Li doping amounts in one pot by using citric acid as a gelling agent. 2 The catalyst is used to catalyze the transesterification of glycerol to synthesize glycerol carbonate. A series of characterizations of the catalyst show that Li can be doped into CeO 2 In the lattice, [Li + O - ] The basic sites of the catalyst were used to increase the glycerol conversion rate to 90.16% and the glycerol carbonate yield to 90.04%. After the catalyst was reused five times, the glycerol carbonate yield only decreased by 7.98 percentage points, indicating that the active components are not easily lost. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 CeO 2 and 0.3Li-CeO 2 SEM images of Figure 2 0.3Li-CeO 2 TEM and HRTEM images; Figure 3 CeO 2 and 0.3Li-CeO 2 N 2 Physical adsorption curve and pore size distribution diagram; Figure 4 CeO 2 and 0.3Li-CeO 2Specific surface area, pore volume and pore size diagram; Figure 5 This is the effect of the molar ratio of Li to Ce on the catalytic activity. DETAILED DESCRIPTION

[0011] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0012] See also Figure 1-5 , a process for preparing fatty acid glyceride, comprising the following material components: 10-100 parts of glycerol, 20-55 parts of dimethyl carbonate, and 1-50 parts of a catalyst; The catalyst comprises the following material compositions: 1-30 parts of cerium nitrate solution, 1-30 parts of LiNO3 and 1-30 parts of citric acid ethanol solution.

[0013] A process for preparing fatty acid glyceride comprises the following steps: S1: Add glycerol and dimethyl carbonate into a 50 mL single-necked flask; S2: Then, a catalyst is added and the reaction is carried out by heating under reflux conditions; S3: After cooling to room temperature, centrifuge to separate the catalyst, and take the supernatant as the product; In step S1, the mass ratio of glycerol to dimethyl carbonate is 1:2; In step S2, the optimal heating reaction condition for preparing glycerol carbonate by transesterification of glycerol and dimethyl carbonate is a temperature of 100°C; In step S2, the heating reaction time is 2.0 h, and the amount of catalyst used is 1% of the mass of glycerol.

[0014] Preferably, the specific preparation method of the catalyst is as follows: S1: Add 50 mL of cerium nitrate solution (0.5 mol / L) to a 250 mL flask, add LiNO3, and after the solid is completely dissolved, add 50 mL of citric acid ethanol solution (0.5 mol / L) to control the molar ratio of citric acid to cerium atoms; S2: The solution was heated at 90°C to evaporate the solvent, forming a pale yellow gel, which was dried in an oven at 100°C overnight to obtain a foamy substance; S3: Grind the obtained foamy substance, put it into a crucible, heat it to 200℃ at 1℃ / min for 3h, and then heat it to 600℃ at 5℃ / min for 2h to obtain Li-doped CeO 2Catalyst, denoted as xLi-CeO 2 , where x is the molar ratio of Li to Ce; S4: CeO2 was prepared by the same method without adding LiNO3.

[0015] Preferably, in step S3, the molar ratio of Li to Ce is 0.3:1.

[0016] from Figure 1 It can be seen that the prepared CeO 2 The surface is lamellar and has no regular morphology.

[0017] Depend on Figure 1 b and Figure 1 c It can be seen that Li-CeO 2 The surface morphology is spherical, and the particle size and shape are relatively uniform. This is consistent with the fact that the peak shape becomes sharper after a certain amount of Li is doped in XRD analysis, which is conducive to the CeO 2 Better crystallization correspondence.

[0018] Effect of Li doping on CeO 2 The surface morphology of the samples is greatly affected because electron exchange occurs between Li atoms and Ce atoms.

[0019] This regular spherical morphology on the catalyst surface also indicates the uniform distribution of active centers, which is conducive to full contact between reactants and catalysts, thereby improving catalytic activity.

[0020] Depend on Figure 2 a It can be seen that the catalyst is in the shape of aggregated spheres, and the particle size of Li-doped CeO2 particles calcined at 600°C is (90±20) nm.

[0021] In the HRTEM image, it can be observed that the 2 (200) lattice (see Figure 2 b), further proved that CeO 2 The presence of crystals.

[0022] This shows that Li doping has an effect on CeO 2 The lattice structure is not greatly affected and the catalyst exhibits a good crystalline structure.

[0023] Depend on Figure 3 It can be seen that CeO 2 There is a very obvious H3 type hysteresis loop.

[0024] Depend on Figure 4 It can be seen that CeO 2 The pore size is 9.8681nm, 0.3Li-CeO 2 The pore size is 41.7226nm, and both have a mesoporous structure.

[0025] After Li doping, the pore size of the catalyst changed significantly, which may be related to the 2 It is related to the appearance of stacking holes. It can also be clearly seen from the TEM image that the small balls are stacked to form obvious stacking holes (see Figure 2 a).

[0026] The emergence of such stacked pores enables the catalyst to allow larger reactant molecules to pass through the pores, increasing the diffusion rate of the reactants and thus accelerating the reaction efficiency.

[0027] Under the conditions of reaction time 2.0h, reaction temperature 100℃, catalyst dosage 1% (based on glycerol mass) and glycerol to dimethyl carbonate molar ratio 1:2, the effect of Li to Ce molar ratio on catalytic activity was investigated. The results are shown in Figure 5 .

[0028] Depend on Figure 5 It can be seen that when the molar ratio of Li to Ce is 0.3:1, it exhibits better catalytic activity.

[0029] When the molar ratio of Li to Ce is 0.1:1, the catalyst activity is poor, which may be due to the small amount of Li doping, resulting in fewer basic sites on the catalyst surface.

[0030] As the amount of Li doping increases, the glycerol conversion rate and the glycerol carbonate yield increase. However, when the amount of Li doping increases further, excessive Li may cover the basic sites on the catalyst surface, resulting in a decrease in the glycerol conversion rate and the glycerol carbonate yield.

[0031] Therefore, the optimal Li to Ce molar ratio is selected to be 0.3:1.

[0032] Li-CeO with different Li doping amounts was synthesized by one-pot method using citric acid as gelling agent. 2 The catalyst is used to catalyze the transesterification of glycerol to synthesize glycerol carbonate. A series of characterizations of the catalyst show that Li can be doped into CeO 2 In the lattice, [Li + O - ]Alkaline sites. The catalyst activity was best when the molar ratio of Li, Ce and citric acid was 0.3:1:1. The optimal conditions for the transesterification of glycerol and dimethyl carbonate to prepare glycerol carbonate were reaction temperature 100℃, reaction time 2.0h, catalyst dosage of 1% of glycerol mass, and molar ratio of glycerol to dimethyl carbonate 1:2. Under these conditions, the glycerol conversion rate was 90.16% and the glycerol carbonate yield was 90.04%. After the catalyst was reused 5 times, the glycerol carbonate yield only decreased by 7.98 percentage points, indicating that the active components are not easily lost.

[0033] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0034] Although 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 the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A process for preparing fatty acid glyceride, characterized in that, The composition comprises the following materials: 10-100 parts of glycerol, 20-55 parts of dimethyl carbonate, and 1-50 parts of catalyst; The catalyst comprises the following substances: 1-30 parts of cerium nitrate solution, 1-30 parts of LiNO3, and 1-30 parts of citric acid ethanol solution.

2. The preparation process of a fatty acid glyceride according to claim 1, characterized in that: The following steps are involved: S1: Add glycerol and dimethyl carbonate into a 50 mL single-necked flask; S2: Then, a catalyst is added and the reaction is carried out by heating under reflux conditions; S3: After cooling to room temperature, centrifuge to separate the catalyst, and take the supernatant as the product; In step S1, the mass ratio of glycerol to dimethyl carbonate is 1:2; In step S2, the optimal heating reaction condition for preparing glycerol carbonate by transesterification of glycerol and dimethyl carbonate is a temperature of 100°C; In step S2, the heating reaction time is 2.0 h, and the amount of catalyst used is 1% of the mass of glycerol.

3. The preparation process of a fatty acid glyceride according to claim 2, characterized in that: The specific preparation method of the catalyst is as follows: S1: Add 50 mL of cerium nitrate solution (0.5 mol / L) to a 250 mL flask, add LiNO3, and after the solid is completely dissolved, add 50 mL of citric acid ethanol solution (0.5 mol / L) to control the molar ratio of citric acid to cerium atoms; S2: The solution was heated at 90°C to evaporate the solvent, forming a pale yellow gel, which was dried in an oven at 100°C overnight to obtain a foamy substance; S3: Grind the obtained foamy substance, put it into a crucible, heat it to 200℃ at 1℃ / min for 3h, and then heat it to 600℃ at 5℃ / min for 2h to obtain Li-doped CeO2 catalyst, which is denoted as xLi-CeO2, where x is the molar ratio of Li to Ce. S4: CeO2 was prepared by the same method without adding LiNO3.

4. The preparation process of a fatty acid glyceride according to claim 3, characterized in that: In step S3, the molar ratio of Li to Ce is 0.3:1.

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