Method for reducing peroxide value and anisidine value in ethyl polyenoate

Abstract

The invention provides a method for reducing peroxide value and anisidine value in ethyl polyenoate, which comprises the following steps: preheating an ethyl polyenoate raw material under the condition of vacuumizing or negative pressure, and pumping the preheated ethyl polyenoate raw material into first-stage molecular distillation equipment through a knockout pump; carrying out molecular distillation by controlling the first-stage molecular distillation temperature at 115-135 DEG C and the mass ratio of the light phase to the heavy phase at (0.5-5): (95-99.5), removing low-boiling-point peroxides and aldehyde and ketone substances through molecular distillation, and collecting a first-stage molecular distillation heavy phase; pumping the primary molecular distillation heavy phase into secondary molecular distillation equipment through a knockout pump; and carrying out molecular distillation by controlling the secondary molecular distillation temperature at 120-150 DEG C and the mass ratio of the light phase to the heavy phase at (95-98): (2-5), removing high-boiling-point peroxides and aldehyde and ketone substances through molecular distillation, and collecting a secondary molecular distillation light phase. By adopting a physical purification principle, the peroxide value and anisidine value of the polyenoic acid ethyl ester are reduced, and the method is high in yield, low in energy consumption, simple to operate and suitable for industrial production.

Description

Technical Field

[0001] The invention relates to the technical field of polyenoic acid ethyl ester purification, in particular to a method for reducing the peroxide value and anisidine value in polyenoic acid ethyl ester. Background Art

[0002] Ethyl polyenoate is a kind of oil extracted from fatty fish, rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). As essential fatty acids that humans cannot synthesize by themselves, medical and nutritional studies have shown that EPA and DHA have the functions of inhibiting platelet aggregation, anti-thrombosis, vasodilation and regulating blood lipids to prevent and treat cardiovascular and cerebrovascular diseases, and have certain therapeutic effects on diabetes, inflammation and kidney disease. In addition, DHA also has the functions of promoting the growth and development of brain cells, improving brain function, improving memory and learning ability, enhancing retinal reflex ability, and preventing and treating senile dementia.

[0003] Since polyoleate products contain more "C=C" double bonds, they are easily oxidized to produce a large amount of aldehydes and ketones during processing or storage, resulting in an increase in the peroxide value and anisidine value of polyoleate. The peroxide value is an indicator of the degree of oxidation of oils and fats, which measures the degree of rancidity of oils and fats; the anisidine value is a characterization of the amount of secondary products such as aldehydes and ketones in oils and fats. Small molecules such as free radicals produced after oil oxidation and rancidity can have adverse effects on the human body, and the small molecule aldehydes and ketones of secondary products can destroy the normal physiological functions of human cells. Therefore, the content of such substances must be controlled in polyoleate products. The European Pharmacopoeia requires the peroxide value to be less than 10meq / kg and the anisidine value to be less than 2.0; the United States Pharmacopoeia requires the peroxide value to be less than 10meq / kg and the anisidine value to be less than 15. Therefore, the peroxide value and anisidine value of polyoleate should be controlled during the deep processing of polyoleate.

[0004] Patent document CN102976936A discloses a method for reducing the peroxide value and anisidine value in polyunsaturated fatty acid ethyl esters: unsaturated fatty acid ethyl esters are used as raw materials, and sodium borohydride is used to react with carbon-oxygen double bonds under certain conditions, so that aldehydes and ketones are converted into alcohols, thereby achieving the purpose of reducing the peroxide value and anisidine value. However, sodium borohydride is very flammable, and it can cause combustion when it encounters water, humid air, acids, oxidants, high heat and open flames, and there are great safety hazards during use; in addition, sodium borohydride itself is toxic and can strongly irritate the mucous membrane, upper respiratory tract, eyes and skin. After inhalation, it can cause laryngeal and bronchial spasm, inflammation and edema, chemical pneumonia and pulmonary edema and cause death. Various protective equipment must be equipped when using it, which not only greatly increases the production cost, but also the chemical reaction will produce fat-soluble chemical reaction residual products that are harmful to the human body and are difficult to remove.

[0005] Patent document CN102965193B discloses a method for reducing the peroxide value and anisidine value in a fatty acid ethyl ester product, wherein the supercritical extraction of polyoleate ethyl ester is performed by liquid carbon dioxide to separate fatty aldehydes and fatty ketones, and the fatty acid ethyl ester is extracted and separated, and finally a fatty acid ethyl ester product having a peroxide value lower than 2 meq / kg and anisidine value lower than 10 is obtained. Although this method can reduce the peroxide value and anisidine value of fatty acid ethyl ester to a certain value, its operation needs to be carried out under high pressure conditions, and the supercritical extraction equipment is expensive, the operation cost is high, and the operation is dangerous.

[0006] Patent document CN105733818A discloses a method for reducing the anisidine value of DHA oil, firstly, aldehyde substances in oil are fully dissociated with concentrated phosphoric acid, then urea or arginine are added to combine with aldehyde substances to generate imine compounds insoluble in oil, and the primary finished product is filtered, and then the primary finished product is filtered through a high-pressure silica gel chromatography column, and the oxidation products in DHA oil are further adsorbed, and the anisidine value of DHA oil can be effectively reduced to about 2.0. Although this method can reduce the anisidine value to less than 2.0, its chemical reaction process process route is long, phosphoric acid and urea are used, and improper use of phosphoric acid will cause the acid value of oil to be too high, and the chemical reaction will also produce fat-soluble chemical reaction residual products that are difficult to remove and harmful to the human body. In addition, high-pressure silica gel chromatography columns are used for filtration, and the cost is high, and industrial production cannot be achieved.

[0007] Patent document CN103343048B discloses a method for reducing the anisidine value of high-content fish oil, under the protection of inert gas, at a temperature of 5°C-85°C, an adsorbent is used for primary adsorption, the fish oil after filtering out the adsorbent is subjected to molecular distillation, and then under the protection of inert gas, at a temperature of 5°C-85°C, the fish oil is subjected to secondary adsorption with an adsorbent, and finally the anisidine value of high-content fish oil can be reduced. The adsorbent is mainly one or two of activated carbon, activated clay, attapulgite, bentonite, zeolite, silica gel, diatomaceous earth, and activated alumina. Although this method can reduce the anisidine value, the number of adsorptions is twice, and the amount of adsorbent used is large, resulting in a relatively low yield, a large adsorption loss, and the used adsorbent cannot be reused, resulting in a high production cost.

[0008] In summary, the above-mentioned prior art has the following disadvantages: 1) the addition of toxic and harmful reducing agents for the reaction is not only dangerous to operate but also affects the quality of ethyl polyenoate, and the chemical reaction also produces fat-soluble chemical reaction residual products that are harmful to the human body and are difficult to remove; 2) the adsorption of multiple adsorbents increases the number of adsorptions, making the operation cumbersome, and the high oil absorption rate of the adsorbent leads to a low yield and poor economic efficiency; 3) some methods cannot significantly reduce the peroxide value and anisidine value of ethyl polyenoate, and are only suitable for products whose peroxide value and anisidine value are not high.

[0009] In view of this, the present invention is proposed. Summary of the invention

[0010] The invention aims to provide a method for reducing the peroxide value and anisidine value in ethyl polyenoate. The method can reduce the peroxide value and anisidine value of ethyl polyenoate, has high yield, low energy consumption, simple operation and is suitable for industrial production.

[0011] The first aspect of the present invention provides a method for reducing the peroxide value and anisidine value in ethyl polyenoate, comprising the steps of:

[0012] S1. Under vacuum or negative pressure conditions, preheat the polyoleate raw material and pump it into the first-stage molecular distillation equipment through a feed pump.

[0013] The primary molecular distillation temperature is controlled at 115-135° C., the mass ratio of the light phase to the heavy phase is (0.5-5):(95-99.5), and molecular distillation is performed to remove the low-boiling peroxides and aldehydes and ketones remaining in the polyolefin ethyl ester by molecular distillation, and the primary molecular distillation heavy phase is collected.

[0014] Under the condition of primary molecular distillation temperature of 115-135°C, low-boiling unstable peroxides can be converted into low-boiling aldehydes and ketones, and low-boiling peroxides and aldehydes and ketones can be removed, thereby reducing the peroxide value and anisidine value.

[0015] Under the condition that the mass ratio of light phase to heavy phase is (0.5-5):(95-99.5), low-boiling point peroxides, aldehydes and ketones can be effectively removed, the output of low-boiling point substances can be reduced, the product yield can be improved, and material loss can be reduced.

[0016] S2. The heavy phase of the first-stage molecular distillation is pumped into the second-stage molecular distillation equipment through a feed pump.

[0017] The secondary molecular distillation temperature is controlled at 120-150° C., and the mass ratio of the light phase to the heavy phase is (95-98):(2-5) for molecular distillation. The high-boiling point peroxides and aldehydes and ketones remaining in the polyoleate are removed by molecular distillation, and the secondary molecular distillation light phase is collected.

[0018] Under the condition of secondary molecular distillation temperature of 120-150°C, high-boiling point unstable peroxides can be converted into high-boiling point aldehydes and ketones, high-boiling point peroxides and aldehydes and ketones can be removed, and the peroxide value and anisidine value can be reduced.

[0019] Under the condition that the mass ratio of light phase to heavy phase is (95-98):(2-5), high-boiling point peroxide aldehydes and ketones can be effectively removed, the output of high-boiling point substances can be reduced, the product yield can be increased, and material loss can be reduced.

[0020] Preferably, in step S1, under vacuum conditions, the vacuum degree is 1-100 Pa, and the entire distillation process is carried out under vacuum conditions to reduce the distillation temperature and prevent the polyolefin ethyl ester from being converted into peroxides or aldehydes or ketones under high temperature conditions.

[0021] Preferably, in step S1, the preheating temperature is 75-95°C, and the material is preheated in advance to more effectively remove the low-boiling peroxides and aldehydes and ketones in the first distillation.

[0022] Preferably, in step S1, the speed of the feed pump is controlled at 60-120 kg / h. A lower speed affects the production efficiency, while a higher speed affects the distillation effect.

[0023] Preferably, in step S1, the primary molecular distillation temperature is controlled at 120-130°C.

[0024] Preferably, the mass ratio of the light phase to the heavy phase is 0.5:99.5.

[0025] Preferably, in step S2, the speed of the feed pump is controlled at 60-120 kg / h.

[0026] Preferably, in step S2, the secondary molecular distillation temperature is controlled at 130-140°C.

[0027] Preferably, the mass ratio of the light phase to the heavy phase is 98:2 or 95:5.

[0028] The second aspect of the present invention provides a polyenoic acid ethyl ester product obtained by using the above-mentioned method for reducing the peroxide value and anisidine value in polyenoic acid ethyl ester.

[0029] Preferably, the peroxide value of the polyoleate product is lower than 1 meq / kg and the anisidine value is lower than 3.

[0030] The present invention has at least the following technical effects:

[0031] The technical solution of the present invention adopts the principle of physical purification, removes low-boiling point peroxides and aldehydes and ketones by primary distillation, and removes high-boiling point peroxides and aldehydes and ketones by secondary distillation, so that the peroxide value and anisidine value of ethyl polyenoate can be reduced, and the yield is high, the energy consumption is low, the operation is simple, and the method can utilize conventional processing equipment of a chemical plant, the economic cost is low, and the method is suitable for industrial production. DETAILED DESCRIPTION

[0032] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0033] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form also includes the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0034] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than 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.

[0035] Example 1

[0036] The present embodiment provides a method for reducing the peroxide value and anisidine value in ethyl polyenoate, comprising the following steps:

[0037] The molecular distillation equipment is evacuated to a vacuum degree of 5 Pa, the preheating temperature is 75-95 ° C, and the polyolefin ethyl ester raw material is pumped into the primary molecular distillation equipment through a feed pump, and the feed pump speed is controlled at 60-80 kg / h;

[0038] The preheated ethyl polyacrylate raw material is subjected to primary distillation by primary molecular distillation, and the distillation temperature is controlled at 120-130° C.; the molecular distillation is performed at a mass ratio of light phase to heavy phase of 0.5:99.5, and the low-boiling point peroxides and aldehydes and ketones remaining in the ethyl polyacrylate are removed by molecular distillation, and the primary molecular distillation heavy phase is collected;

[0039] The heavy phase material of the first-stage molecular distillation is pumped into the second-stage molecular distillation equipment through a pump, and the pump speed is controlled at 60-80kg / h;

[0040] The secondary molecular distillation temperature is controlled at 130° C. The mass ratio of the light phase to the heavy phase is 98:2 for secondary molecular distillation. The high-boiling point peroxides, aldehydes and ketones remaining in the polyoleate are removed by molecular distillation. The secondary molecular distillation light phase is collected to obtain the treated polyoleate.

[0041] After testing, the yield of polyenoic acid ethyl ester after treatment was 95%-98%, the peroxide value dropped from 15meq / kg to below 1meq / kg, and the anisidine value dropped from 25 to below 3.

[0042] Example 2

[0043] The present embodiment provides a method for reducing the peroxide value and anisidine value in ethyl polyenoate, comprising the following steps:

[0044] The molecular distillation equipment is evacuated to a vacuum degree of 5 Pa, the preheating temperature is 75-95 ° C, and the polyolefin ethyl ester raw material is pumped into the primary molecular distillation equipment through a feed pump, and the feed pump speed is controlled at 60-80 kg / h;

[0045] The preheated ethyl polyacrylate raw material is subjected to primary distillation by primary molecular distillation, and the distillation temperature is controlled at 120-130° C.; the molecular distillation is performed at a mass ratio of light phase to heavy phase of 0.5:99.5, and the low-boiling point peroxides and aldehydes and ketones remaining in the ethyl polyacrylate are removed by molecular distillation, and the primary molecular distillation heavy phase is collected;

[0046] The heavy phase material of the first-stage molecular distillation is pumped into the second-stage molecular distillation equipment through a pump, and the pump speed is controlled at 60-80kg / h;

[0047] The secondary molecular distillation temperature is controlled at 140° C. The mass ratio of the light phase to the heavy phase is 98:2 for secondary molecular distillation. The high-boiling point peroxides, aldehydes and ketones remaining in the polyoleate are removed by molecular distillation. The secondary molecular distillation light phase is collected to obtain the treated polyoleate.

[0048] After testing, the yield of polyenoic acid ethyl ester after treatment was 95%-98%, the peroxide value dropped from 15meq / kg to below 1meq / kg, and the anisidine value dropped from 25 to below 3.

[0049] Example 3

[0050] The present embodiment provides a method for reducing the peroxide value and anisidine value in ethyl polyenoate, comprising the following steps:

[0051] The molecular distillation equipment is evacuated to a vacuum degree of 5 Pa, the preheating temperature is 75-95 ° C, and the polyolefin ethyl ester raw material is pumped into the primary molecular distillation equipment through a feed pump, and the feed pump speed is controlled at 60-80 kg / h;

[0052] The preheated ethyl polyacrylate raw material is subjected to primary distillation by primary molecular distillation, and the distillation temperature is controlled at 120-130° C.; the molecular distillation is performed at a mass ratio of light phase to heavy phase of 0.5:99.5, and the low-boiling point peroxides and aldehydes and ketones remaining in the ethyl polyacrylate are removed by molecular distillation, and the primary molecular distillation heavy phase is collected;

[0053] The heavy phase material of the first-stage molecular distillation is pumped into the second-stage molecular distillation equipment through a pump, and the pump speed is controlled at 60-80kg / h;

[0054] The secondary molecular distillation temperature is controlled at 130° C. The mass ratio of the light phase to the heavy phase is 95:5 for secondary molecular distillation. The high-boiling point peroxides, aldehydes and ketones remaining in the polyoleate are removed by molecular distillation. The secondary molecular distillation light phase is collected to obtain the treated polyoleate.

[0055] After testing, the yield of polyenoic acid ethyl ester after treatment was 95%-98%, the peroxide value dropped from 15meq / kg to below 1meq / kg, and the anisidine value dropped from 25 to below 3.

[0056] Example 4

[0057] The present embodiment provides a method for reducing the peroxide value and anisidine value in ethyl polyenoate, comprising the following steps:

[0058] The molecular distillation equipment is evacuated to a vacuum degree of 5 Pa, the preheating temperature is 75-95 ° C, and the polyolefin ethyl ester raw material is pumped into the primary molecular distillation equipment through a feed pump, and the feed pump speed is controlled at 60-80 kg / h;

[0059] The preheated ethyl polyacrylate raw material is subjected to primary distillation by primary molecular distillation, and the distillation temperature is controlled at 120-130° C.; the molecular distillation is performed at a mass ratio of light phase to heavy phase of 0.5:99.5, and the low-boiling point peroxides and aldehydes and ketones remaining in the ethyl polyacrylate are removed by molecular distillation, and the primary molecular distillation heavy phase is collected;

[0060] The heavy phase material of the first-stage molecular distillation is pumped into the second-stage molecular distillation equipment through a pump, and the pump speed is controlled at 60-80kg / h;

[0061] The secondary molecular distillation temperature is controlled at 140° C. The mass ratio of the light phase to the heavy phase is 95:5 for secondary molecular distillation. The high-boiling point peroxides, aldehydes and ketones remaining in the polyolefin ethyl ester are removed by molecular distillation. The secondary molecular distillation light phase is collected to obtain the treated polyolefin ethyl ester.

[0062] After testing, the yield of polyenoic acid ethyl ester after treatment was 95%-98%, the peroxide value dropped from 15meq / kg to below 1meq / kg, and the anisidine value dropped from 25 to below 3.

[0063] Comparative Example 1

[0064] This comparative example is basically the same as Example 1, except that the molecular distillation equipment is evacuated to a vacuum degree of 150 Pa.

[0065] After testing, the yield of polyenoic acid ethyl ester after treatment was 90.6%, the peroxide value was 14.8 meq / kg, and the anisidine value was 25.6.

[0066] Comparative Example 2

[0067] This comparative example is basically the same as Example 1, except that the preheating temperature is 70°C.

[0068] After testing, the yield of polyenoic acid ethyl ester after treatment was 91.1%, the peroxide value was 14.1 meq / kg, and the anisidine value was 25.0.

[0069] Comparative Example 3

[0070] This comparative example is basically the same as Example 1, except that the polyenoic acid ethyl ester raw material is pumped into the primary molecular distillation equipment through a pump, and the pump speed is controlled at 130 kg / h.

[0071] After testing, the yield of polyenoic acid ethyl ester after treatment was 92.7%, the peroxide value was 17.3 meq / kg, and the anisidine value was 28.4.

[0072] Comparative Example 4

[0073] This comparative example is basically the same as Example 1, except that the preheated ethyl polyenoate raw material is subjected to primary distillation by primary molecular distillation, and the distillation temperature is controlled at 140°C.

[0074] After testing, the yield of polyenoic acid ethyl ester after treatment was 85.4%, the peroxide value was 0.9 meq / kg, and the anisidine value was 2.7.

[0075] Comparative Example 5

[0076] This comparative example is basically the same as Example 1, except that the mass ratio of the light phase to the heavy phase in the first-stage molecular distillation is 10:90.

[0077] After testing, the yield of polyenoic acid ethyl ester after treatment was 86.2%, the peroxide value was 0.9 meq / kg, and the anisidine value was 2.9.

[0078] Comparative Example 6

[0079] This comparative example is basically the same as Example 1, except that the heavy phase material of the primary molecular distillation is pumped into the secondary molecular distillation equipment through a pump, and the pump speed is controlled at 130 kg / h.

[0080] After testing, the yield of polyenoic acid ethyl ester after treatment was 93.4%, the peroxide value was 15.4 meq / kg, and the anisidine value was 25.4.

[0081] Comparative Example 7

[0082] This comparative example is basically the same as Example 1, except that the secondary molecular distillation temperature is controlled at 150°C.

[0083] After testing, the yield of polyenoic acid ethyl ester after treatment was 96.4%, the peroxide value was 10.4 meq / kg, and the anisidine value was 22.4.

[0084] Comparative Example 8

[0085] This comparative example is basically the same as Example 1, except that the mass ratio of the light phase to the heavy phase in the secondary molecular distillation is 90:10.

[0086] After testing, the yield of polyenoic acid ethyl ester after treatment was 98.2%, the peroxide value was 13.6 meq / kg, and the anisidine value was 23.6.

[0087] In summary, the present invention adopts the principle of physical purification, removes low-boiling point peroxides and aldehydes and ketones by primary distillation, and removes high-boiling point peroxides and aldehydes and ketones by secondary distillation, so that the peroxide value and anisidine value of ethyl polyenoate can be reduced, and the yield is high, the energy consumption is low, the operation is simple, and the method can utilize conventional processing equipment in chemical plants, the economic cost is low, and the method is suitable for industrial production.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for reducing the peroxide value and anisidine value in ethyl polyenoate, characterized in that: The steps include: S1. Under vacuum or negative pressure conditions, preheat the polyenoic acid ethyl ester raw material and pump it into a primary molecular distillation device through a feed pump; Controlling the primary molecular distillation temperature at 115-135° C. and carrying out molecular distillation at a mass ratio of light phase to heavy phase of (0.5-5):(95-99.5), removing residual low-boiling peroxides and aldehydes and ketones in ethyl polyenoate by molecular distillation, and collecting the primary molecular distillation heavy phase; S2, pumping the heavy phase of the first-stage molecular distillation into the second-stage molecular distillation equipment through a feed pump; The secondary molecular distillation temperature is controlled at 120-150° C., and the mass ratio of the light phase to the heavy phase is (95-98):(2-5) for molecular distillation. The high-boiling point peroxides and aldehydes and ketones remaining in the polyoleate are removed by molecular distillation, and the secondary molecular distillation light phase is collected.

2. The method for reducing the peroxide value and anisidine value in ethyl polyenoate according to claim 1, characterized in that: In step S1, under vacuum conditions, the vacuum degree is 1-100 Pa; the preheating temperature is 75-95°C.

3. The method for reducing the peroxide value and anisidine value in ethyl polyenoate according to claim 1, characterized in that: In step S1, the speed of the feed pump is controlled at 60-120 kg / h.

4. The method for reducing the peroxide value and anisidine value in ethyl polyenoate according to claim 1, characterized in that: In step S1, the primary molecular distillation temperature is controlled at 120-130°C.

5. The method for reducing peroxide value and anisidine value in ethyl polyenoate according to claim 1, wherein in step S1, the light phase and heavy phase mass ratio is 0.5:99.

5.

6. The method for reducing the peroxide value and anisidine value in ethyl polyenoate according to claim 1, characterized in that: In step S2, the speed of the feed pump is controlled at 60-120 kg / h.

7. The method for reducing the peroxide value and anisidine value in ethyl polyenoate according to claim 1, characterized in that: In step S2, the secondary molecular distillation temperature is controlled at 130-140°C.

8. The method for reducing peroxide value and anisidine value in ethyl polyenoate according to claim 1, wherein in step S2, the light phase and heavy phase mass ratio is 98:2 or 95:

5.

9. A polyolefin ethyl ester product, characterized in that: The method for reducing the peroxide value and anisidine value in ethyl polyenoate according to any one of claims 1 to 8 is adopted to obtain the product.

10. The polyoleate product according to claim 9, characterized in that: The peroxide value of the polyoleate product is less than 1 meq / kg and the anisidine value is less than 3.