Preparation method and application of soybean acidified oil

Abstract

The present invention relates to the technical field of acidified oil, and in particular to a preparation method and application of soybean acidified oil. The present application discloses a preparation method of soybean acidified oil, comprising the following steps: (1) pretreatment, fully mixing soybean soap stock and sodium benzenesulfonate solution, then standing and separating, and collecting the upper soap stock; (2) acidification treatment, heating the lower soap stock to 95-100°C, adding concentrated sulfuric acid under stirring conditions, and collecting the upper oil layer after the reaction is completed; (3) decolorization treatment, fully mixing the upper oil layer and a modified adsorbent, and performing decolorization treatment; after the decolorization treatment, filtering and standing and separating to obtain soybean acidified oil. The preparation method described in the present application prepares an acidified oil with light color and high transparency, and the acidified oil has low acid value content, low peroxide value, and high saponification value, and can be used as biodiesel.

Description

Technical Field

[0001] The present invention relates to the technical field of acidified oil, in particular to a preparation method and application of soybean acidified oil. Background Art

[0002] Soybean oil, a byproduct of the vegetable oil processing industry, is produced during the soybean oil refining process. Specifically, it is extracted through an acidification process on the soapstock byproduct of the soybean oil refining process. During soybean oil refining, the hydrated phospholipids, commonly known as "oil stock," undergo a sulfuric acid-catalyzed acidification reaction.

[0003] In current market applications, soybean oil is primarily used to produce industrial-grade oleic acid or, after hydrogenation, stearic acid. Both conversion pathways require hydrolysis of the soybean oil to convert the neutral oils into free fatty acids. Distillation then yields mixed soybean fatty acids, which are then further processed into the desired end product.

[0004] The current soybean acidified oil is dark in color and not very transparent, which affects its use in subsequent processing, such as in biodiesel production.

[0005] In order to solve the technical difficulties of the prior art, the present application provides a preparation method and application of soybean acidified oil. Summary of the Invention

[0006] In order to overcome the shortcomings of the existing technology, the present application provides a preparation method and application of soybean acidified oil. The method comprises pre-treating the soap stock, performing acid hydrolysis, and finally performing a decolorization treatment to prepare an acidified oil with light color and high transparency. The acidified oil has low acid value, low peroxide value, and high saponification value, and can be used as biodiesel.

[0007] The technical solution adopted by this application to solve its technical problems is:

[0008] The first object of the present application is to provide a method for preparing soybean acidified oil, comprising the following steps:

[0009] (1) Pretreatment

[0010] The soybean soap stock and the sodium benzenesulfonate solution are fully mixed, and then allowed to stand for separation, and the upper soap stock is collected;

[0011] (2) Acidification treatment

[0012] Heat the lower soap stock to 95-100℃, add concentrated sulfuric acid under stirring, and collect the upper oil layer after the reaction is completed;

[0013] (3) Decolorization

[0014] The upper oil layer and 0.05-0.08% by weight of the modified adsorbent of soybean soap stock are fully mixed and decolorized; after the decolorization, the mixture is filtered and allowed to stand for separation to obtain soybean acidified oil.

[0015] Preferably, in step (1), the mass concentration of the sodium benzenesulfonate solution is 0.1-0.5%; and the amount of the sodium benzenesulfonate solution added is 0.1%-0.3% of the weight of the soybean soap stock.

[0016] Preferably, in step (1), the mixing is carried out at 50-60°C. In the present application, during the production process of the soap stock, since it contains colloid-soluble hydrophilic impurities such as phospholipids, these impurities are prone to emulsification during hydration degumming. Emulsification will seriously affect the separation efficiency of oils and fats and the quality of the final product. In the pretreatment, by fully mixing the soybean soap stock with the sodium benzenesulfonate solution, the surface charge of the dispersed phase particles of the soybean soap stock can be neutralized, the potential of the particles can be eliminated or reduced, and the hydration degree can be reduced, thereby reducing the emulsification phenomenon.

[0017] Preferably, in step (2), after adding concentrated sulfuric acid, when the pH of the lower aqueous layer of the acidification reaction reaches 3-3.5, the addition of concentrated sulfuric acid is stopped and stirring is continued for 2-3 hours; then concentrated sulfuric acid is added until the oil phase and the aqueous phase are clearly separated.

[0018] Preferably, the modified adsorbent is obtained by treating cellulose acetate with an aminosilane coupling agent and a surfactant.

[0019] Preferably, the aminosilane coupling agent is any one of 3-aminopropyldiethoxymethylsilane and γ-aminopropyltriethoxysilane.

[0020] Preferably, the surfactant is an amino acid surfactant, which is any one of sodium cocoyl glycinate and potassium cocoamide.

[0021] Preferably, the method for preparing the modified adsorbent comprises the following steps: thoroughly mixing cellulose acetate, montmorillonite, an aminosilane coupling agent, a solvent, and sulfuric acid, followed by a reflux reaction; and after the reflux reaction, adding a surfactant and thoroughly mixing to obtain a modified decolorizer. In the present application, the modified decolorizer contains montmorillonite and cellulose acetate, which have a large specific surface area and porous structure, effectively adsorbing pigments and odorous substances in oils and fats, thereby achieving a decolorization effect. Furthermore, the aminosilane coupling agent in the modified decolorizer can chemically bond with polar substances in oils and fats, immobilizing pigments and odorous substances in the oils and fats by forming chemical bonds, thereby reducing their release. Furthermore, the surfactant component in the modified decolorizer, such as an amino acid surfactant, can reduce the interfacial tension between oils and water, promote the dispersion of pigments and odorous substances in the oils and fats, and facilitate their contact and adsorption with the adsorbent. Through the decolorization process, the modified decolorizer can also improve the oxidative stability of the oils and fats, reducing oxidative deterioration during storage and use, and extending the shelf life of the oils and fats.

[0022] More preferably, the weight ratio of the cellulose acetate, montmorillonite, aminosilane coupling agent, and surfactant is 50:40:(30-40):(2-3).

[0023] The second purpose of the present application is to provide an application of soybean acidified oil, that is, to apply soybean acidified oil to the preparation of biodiesel.

[0024] The beneficial effects of the present invention are:

[0025] 1. The preparation method described in this application effectively removes impurities and pigments in the oil and reduces the acidity through a series of steps such as pretreatment, acidification, and decolorization. The resulting acidified soybean oil has a light yellow appearance, an acidity of 35-41 mg / g, a peroxide value of 6.38-7.01 meq / kg, and a saponification value of 161-169 mg / g, showing the advantages of low acidity, low peroxide value, and high saponification value.

[0026] 2. The soybean acidified oil prepared in this application has low acidity and low peroxide value content, and is suitable as a raw material for biodiesel, thereby improving the quality of raw materials for biodiesel production. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will be further described below with reference to the accompanying drawings and examples.

[0028] Figure 1 This is a process flow chart of the preparation method described in this application. DETAILED DESCRIPTION

[0029] In order to facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the embodiments. The contents mentioned in the embodiments are not intended to limit the present invention.

[0030] As used herein, "and / or" includes the term of any and all combinations of one or more of the associated listed items. The terms used herein are only used to describe specific embodiments and are not intended to limit the invention. As used herein, the singular forms "a", "an", "an" and "the" are also intended to include the plural forms, unless the context clearly indicates otherwise. It is further understood that "including", when used in this specification, specifies the stated features, integers, steps, operations, elements and / or components, but does not preclude the existence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0031] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It is further understood that terms, such as those defined in commonly used dictionaries, are interpreted in accordance with their meanings in the context of the relevant art and are not idealized or overly formalized unless expressly defined herein.

[0032] The exemplary inventions described herein may suitably lack any one or more element limitations not specifically disclosed herein. Therefore, terms such as "comprises," "includes," "contains," and the like should be understood broadly and non-restrictively. In addition, the terminology used herein is used as a description, not a limitation, and it is unintentional to use these terminology expressions that do not include any equivalent characteristics, but only describe a portion of their characteristics, but various modifications are possible within the scope of the invention according to the rights. Therefore, although the present invention has been specifically disclosed through preferred embodiments and optional features, the modifications disclosed herein to embody the changes of the invention may be recorded by those skilled in the art, and such modifications and changes will be considered to be within the scope of the invention.

[0033] The raw materials or reagents used in the embodiments of the present invention and the comparative examples are all purchased from market mainstream manufacturers. The manufacturer or concentration is not specified. They are all analytically pure raw materials or reagents that can be routinely obtained. As long as the desired effect can be achieved, there are no particular restrictions. The reactor and rotary evaporator and other instruments used in the present embodiment are all purchased from market major manufacturers. As long as the desired effect can be achieved, there are no particular restrictions. In the present embodiment, if specific techniques or conditions are not specified, the technology or conditions described in the literature in this area or the product specifications are used.

[0034] The soybean soap stock of the present application is obtained by alkali refining. The general composition varies depending on the process, operation, and raw materials. The weight content of the soybean soap stock is 30-45% saponified matter, 20-30% neutral oil, 40-50% total fatty acids, and the remainder is water, a small amount of fat, and free alkali. Specifically, the soybean soap stock in the embodiment has a weight content of 32% saponified matter, 21% neutral oil, 43% total fatty acids, 2% water, and a small amount of fat and free alkali.

[0035] Example 1

[0036] A method for preparing soybean acidified oil comprises the following steps:

[0037] (1) Pretreatment

[0038] The soybean soap stock and the sodium benzenesulfonate solution are fully mixed at 50° C., then allowed to stand for separation, and the upper layer of the soap stock is collected; the mass concentration of the sodium benzenesulfonate solution is 0.1%; and the amount of the sodium benzenesulfonate solution added is 0.1% of the weight of the soybean soap stock.

[0039] (2) Acidification treatment

[0040] Heat the lower soap stock to 95°C and add concentrated sulfuric acid under stirring. After adding concentrated sulfuric acid, when the pH of the lower water layer of the acidification reaction reaches 3-3.5, stop adding concentrated sulfuric acid and continue stirring for 2 hours. Then add concentrated sulfuric acid until the oil phase and the water phase are clearly separated.

[0041] When the oil phase and the water phase are clearly separated and the reaction is complete, the upper oil layer is collected;

[0042] (3) Decolorization

[0043] The upper oil layer and 0.05% by weight of the modified adsorbent of soybean soap stock are fully mixed and decolorized at 50° C. After decolorization, the mixture is filtered and allowed to stand for separation to obtain soybean acidified oil.

[0044] Specifically, the preparation method of the modified adsorbent comprises the following steps:

[0045] Cellulose acetate (degree of substitution 1.72-1.95), montmorillonite, an aminosilane coupling agent (3-aminopropyldiethoxymethylsilane), and a solvent (ethanol / water: 80 / 20, w / w) were mixed, followed by the addition of concentrated sulfuric acid to adjust the pH to 5-6. The mixture was stirred for 3 hours and refluxed for 5 hours. After the reaction, a surfactant (sodium cocoyl glycinate) was added and thoroughly mixed for 3 hours to obtain a modified adsorbent. The weight ratio of the cellulose acetate, montmorillonite, aminosilane coupling agent, surfactant, and solvent was 50:40:30:2:1000.

[0046] Example 2

[0047] A method for preparing soybean acidified oil comprises the following steps:

[0048] (1) Pretreatment

[0049] The soybean soap stock and the sodium benzenesulfonate solution are fully mixed at 60° C., then allowed to stand for separation, and the upper layer of the soap stock is collected; the mass concentration of the sodium benzenesulfonate solution is 0.5%; and the amount of the sodium benzenesulfonate solution added is 0.3% of the weight of the soybean soap stock.

[0050] (2) Acidification treatment

[0051] Heat the lower soap stock to 100°C and add concentrated sulfuric acid under stirring. After adding concentrated sulfuric acid, when the pH of the lower water layer of the acidification reaction reaches 3-3.5, stop adding concentrated sulfuric acid and continue stirring for 3 hours. Then add concentrated sulfuric acid until the oil phase and the water phase are clearly separated.

[0052] When the oil phase and the water phase are clearly separated and the reaction is complete, the upper oil layer is collected;

[0053] (3) Decolorization

[0054] The upper oil layer and 0.08% by weight of the modified adsorbent of soybean soap stock are fully mixed and decolorized at 60° C. After decolorization, the mixture is filtered and allowed to stand for separation to obtain soybean acidified oil.

[0055] Specifically, the preparation method of the modified adsorbent comprises the following steps:

[0056] Cellulose acetate (degree of substitution 1.72-1.95), montmorillonite, an aminosilane coupling agent (γ-aminopropyltriethoxysilane), and a solvent (ethanol / water: 80 / 20, w / w) were mixed, sulfuric acid was added, the pH was adjusted to 5-6, stirring was performed for 3 hours, and reflux reaction was performed for 6 hours. After the reaction, a surfactant (potassium cocoamidate) was added and thoroughly mixed for 4 hours to obtain a modified adsorbent. The weight ratio of the cellulose acetate, montmorillonite, aminosilane coupling agent, surfactant, and solvent was 50:40:40:3:1000.

[0057] Example 3

[0058] A method for preparing soybean acidified oil comprises the following steps:

[0059] (1) Pretreatment

[0060] The soybean soap stock and the sodium benzenesulfonate solution are fully mixed at 55° C., then allowed to stand for separation, and the upper layer of the soap stock is collected; the mass concentration of the sodium benzenesulfonate solution is 0.4%; and the amount of the sodium benzenesulfonate solution added is 0.2% of the weight of the soybean soap stock.

[0061] (2) Acidification treatment

[0062] Heat the lower soap stock to 98°C and add concentrated sulfuric acid under stirring. After adding concentrated sulfuric acid, when the pH of the lower water layer of the acidification reaction reaches 3-3.5, stop adding concentrated sulfuric acid and continue stirring for 2.5 hours. Then add concentrated sulfuric acid until the oil phase and the water phase are clearly separated.

[0063] When the oil phase and the water phase are clearly separated and the reaction is complete, the upper oil layer is collected;

[0064] (3) Decolorization

[0065] The upper oil layer and 0.07% by weight of the modified adsorbent of soybean soap stock are fully mixed and decolorized at 55° C. After decolorization, the mixture is filtered and allowed to stand for separation to obtain soybean acidified oil.

[0066] Specifically, the preparation method of the modified adsorbent comprises the following steps:

[0067] Cellulose acetate (degree of substitution 1.72-1.95), montmorillonite, an aminosilane coupling agent (γ-aminopropyltriethoxysilane), and a solvent (ethanol / water: 80 / 20, w / w) were mixed, sulfuric acid was added, the pH was adjusted to 5-6, stirring was performed for 3 hours, and reflux reaction was performed for 5-6 hours. After the reaction, a surfactant (potassium cocoamidate) was added and thoroughly mixed for 3.5 hours to obtain a modified adsorbent. The weight ratio of the cellulose acetate, montmorillonite, aminosilane coupling agent, surfactant, and solvent was 50:40:35:2.5:1000.

[0068] Example 4

[0069] A method for preparing soybean acidified oil comprises the following steps:

[0070] (1) Pretreatment

[0071] The soybean soap stock and the sodium benzenesulfonate solution are fully mixed at 60° C., then allowed to stand for separation, and the upper layer of the soap stock is collected; the mass concentration of the sodium benzenesulfonate solution is 0.1%; and the amount of the sodium benzenesulfonate solution added is 0.3% of the weight of the soybean soap stock.

[0072] (2) Acidification treatment

[0073] Heat the lower soap stock to 95°C and add concentrated sulfuric acid under stirring. After adding concentrated sulfuric acid, when the pH of the lower water layer of the acidification reaction reaches 3-3.5, stop adding concentrated sulfuric acid and continue stirring for 3 hours. Then add concentrated sulfuric acid until the oil phase and the water phase are clearly separated.

[0074] When the oil phase and the water phase are clearly separated and the reaction is complete, the upper oil layer is collected;

[0075] (3) Decolorization

[0076] The upper oil layer and 0.06% by weight of the modified adsorbent of soybean soap stock are fully mixed and decolorized at 55° C. After decolorization, the mixture is filtered and allowed to stand for separation to obtain soybean acidified oil.

[0077] Specifically, the preparation method of the modified adsorbent comprises the following steps:

[0078] Cellulose acetate (degree of substitution 1.72-1.95), montmorillonite, an aminosilane coupling agent (3-aminopropyldiethoxymethylsilane), and a solvent (ethanol / water: 80 / 20, w / w) were mixed, sulfuric acid was added, the pH was adjusted to 5-6, stirring was performed for 3 hours, and reflux reaction was performed for 5 hours. After the reaction, a surfactant (sodium cocoyl glycinate) was added and thoroughly mixed for 4 hours to obtain a modified adsorbent. The weight ratio of the cellulose acetate, montmorillonite, aminosilane coupling agent, surfactant, and solvent was 50:40:30:2:1000.

[0079] Example 5

[0080] A method for preparing soybean acidified oil comprises the following steps:

[0081] (1) Pretreatment

[0082] The soybean soap stock and the sodium benzenesulfonate solution are fully mixed at 60° C., then allowed to stand for separation, and the upper layer of the soap stock is collected; the mass concentration of the sodium benzenesulfonate solution is 0.5%; and the amount of the sodium benzenesulfonate solution added is 0.1% of the weight of the soybean soap stock.

[0083] (2) Acidification treatment

[0084] Heat the lower soap stock to 100°C and add concentrated sulfuric acid under stirring. After adding concentrated sulfuric acid, when the pH of the lower water layer of the acidification reaction reaches 3-3.5, stop adding concentrated sulfuric acid and continue stirring for 2 hours. Then add concentrated sulfuric acid until the oil phase and the water phase are clearly separated.

[0085] (3) Decolorization

[0086] The upper oil layer and 0.05-0.08% by weight of the modified adsorbent of soybean soap stock are fully mixed and decolorized at 60° C. After decolorization, the mixture is filtered and allowed to stand for separation to obtain soybean acidified oil.

[0087] Specifically, the preparation method of the modified adsorbent comprises the following steps:

[0088] Cellulose acetate (degree of substitution 1.72-1.95), montmorillonite, an aminosilane coupling agent (γ-aminopropyltriethoxysilane), and a solvent (ethanol / water: 80 / 20, w / w) were mixed, sulfuric acid was added, the pH was adjusted to 5-6, stirring was performed for 3 hours, and reflux reaction was performed for 5 hours. After the reaction, a surfactant (potassium cocoamidate) was added and thoroughly mixed for 4 hours to obtain a modified adsorbent. The weight ratio of the cellulose acetate, montmorillonite, aminosilane coupling agent, surfactant, and solvent was 50:40:35:3:1000.

[0089] Comparative Example 1

[0090] A method for preparing soybean acidified oil, without pretreatment, and other conditions are the same as those in Example 1;

[0091] Comparative Example 2

[0092] A method for preparing soybean acidified oil, without decolorization, and with other conditions being the same as in Example 1;

[0093] Comparative Example 3

[0094] A method for preparing soybean acidified oil comprises: in step (3), thoroughly mixing the upper oil layer and 0.05% by weight of montmorillonite from soybean soap stock, and decolorizing the mixture at 50°C; filtering the mixture after decolorization and allowing it to stand for separation to obtain soybean acidified oil. Other conditions are the same as those in Example 1;

[0095] The acidified oils prepared in Examples 1-5 and Comparative Examples 1-3 were subjected to the following performance tests, wherein:

[0096] ① Determination of acid value shall be carried out in accordance with GB5530-1985;

[0097] ② The determination of peroxide value (POV) shall be carried out in accordance with GB5538-85;

[0098] ③Saponification value: measured in accordance with GB / T5534-2008;

[0099] ④Appearance inspection, observation with naked eyes.

[0100] Table 1

[0101]

[0102] As can be seen from Table 1, the acidified oil described in the present application has a light yellow appearance, an acidity of 35-41 mg / g, a peroxide value of 6.38-7.01 meq / kg, and a saponification value of 161-169 mg / g, showing the advantages of low acidity, low peroxide value and high saponification value.

[0103] Comparative Example 3, in which only conventional montmorillonite was used for decolorization treatment, had a dark yellow appearance, an acidity of 68 mg / g, a peroxide value of 79.5 meq / kg, and a saponification value of 141 mg / g, exhibiting the disadvantages of high acidity, significantly high peroxide value, and low saponification value.

[0104] The above embodiments are preferred implementation schemes of the present invention. In addition, the present invention can also be implemented in other ways. Any obvious replacement without departing from the concept of the present invention is within the scope of protection of the present invention.

Claims

1. A method for preparing soybean acidified oil, characterized in that: The following steps are involved: (1) Preprocessing The soybean soap stock and the sodium benzenesulfonate solution are fully mixed, and then allowed to stand for separation, and the upper soap stock is collected; (2) Acidification treatment Heat the lower soap stock to 95-100°C and add concentrated sulfuric acid under stirring. When the pH of the lower water layer reaches 3-3.5, stop adding concentrated sulfuric acid and continue stirring for 2-3 hours; then add concentrated sulfuric acid until the oil phase and the water phase are clearly separated. After the reaction is completed, collect the upper oil layer; (3) Decolorization treatment The upper oil layer and 0.05-0.08% by weight of the modified adsorbent of soybean soap stock are fully mixed and decolorized; after decolorization, the mixture is filtered and allowed to stand for separation to obtain soybean acidified oil; In step (1), the mass concentration of the sodium benzenesulfonate solution is 0.1-0.5%; the amount of the sodium benzenesulfonate solution added is 0.1%-0.3% of the weight of the soybean soap stock; the condition for thorough mixing is 50-60°C; The preparation method of the modified adsorbent comprises the following steps: fully mixing cellulose acetate, montmorillonite, an aminosilane coupling agent, a solvent, and sulfuric acid, and then performing a reflux reaction; after the reflux reaction is completed, adding a surfactant and performing a thorough mixing to obtain the modified adsorbent; The weight ratio of the cellulose acetate, montmorillonite, aminosilane coupling agent and surfactant is 50:40:(30-40):(2-3); The aminosilane coupling agent is any one of 3-aminopropyldiethoxymethylsilane and γ-aminopropyltriethoxysilane; The surfactant is an amino acid surfactant.

2. An application of soybean acidified oil, characterized in that, The acidified oil prepared by the preparation method according to claim 1 is applied to the preparation of biodiesel.

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