阅读说明：本技术 一种无溶剂细胞催化制备环氧植物油的方法 (Method for preparing epoxy vegetable oil by solvent-free cell catalysis ) 是由 陈必强 申颖 陈长京 于 2019-10-18 设计创作，主要内容包括：本发明属于生物化工领域,涉及一种无溶剂细胞催化制备环氧植物油的方法。该方法包括：步骤B,将植物油与催化剂、游离脂肪酸混合,并加入过氧化氢溶液,搅拌,进行环氧化反应,得到环氧化反应粗产物；步骤C,将环氧化反应粗产物进行离心处理,除去水层,再将油层与催化剂继续搅拌混合,边抽真空边酯化,得到环氧植物油粗产物；步骤D,将环氧植物油粗产物进行离心处理,获得环氧植物油成品,并将下层催化剂回收后循环使用；其中,所述催化剂为非常规酵母菌的菌体。该方法环氧化反应在无溶剂条件下进行,且反应条件温和,副产物少,没有废弃物产生,催化剂成本低廉且可以重复利用,具有良好的工业化应用前景。(The invention belongs to the field of biochemical engineering, and relates to a method for preparing epoxy vegetable oil by solvent-free cell catalysis. The method comprises the following steps: b, mixing the vegetable oil with a catalyst and free fatty acid, adding a hydrogen peroxide solution, stirring, and carrying out an epoxidation reaction to obtain an epoxidation reaction crude product; step C, carrying out centrifugal treatment on the crude product of the epoxidation reaction, removing a water layer, continuously stirring and mixing an oil layer and the catalyst, and carrying out esterification while vacuumizing to obtain a crude product of the epoxy vegetable oil; step D, carrying out centrifugal treatment on the crude epoxy vegetable oil product to obtain a finished epoxy vegetable oil product, and recycling the lower-layer catalyst for recycling; wherein the catalyst is thallus of unconventional yeast. The epoxidation reaction is carried out under the solvent-free condition, the reaction condition is mild, byproducts are few, no waste is generated, the catalyst is low in cost and can be recycled, and the method has a good industrial application prospect.)

1. A method for preparing epoxidized vegetable oil without solvent and cell catalysis, which comprises the following steps:

b, mixing the vegetable oil with a catalyst and free fatty acid, adding a hydrogen peroxide solution, stirring, and carrying out an epoxidation reaction to obtain an epoxidation reaction crude product;

step C, carrying out centrifugal treatment on the crude product of the epoxidation reaction, removing a water layer, continuously stirring and mixing an oil layer and the catalyst, and carrying out esterification while vacuumizing to obtain a crude product of the epoxy vegetable oil;

step D, carrying out centrifugal treatment on the crude epoxy vegetable oil product to obtain a finished epoxy vegetable oil product;

wherein the catalyst is thallus of unconventional yeast.

2. The method of claim 1, wherein the non-conventional yeast comprises one or more of candida citrinopsis, candida tropicalis, candida parapsilosis, candida olivaceus, candida rugosa, and yarrowia lipolytica.

3. The method according to claim 1 or 2, wherein the microbial cells of the non-conventional yeast are obtained by centrifuging a fermentation product of the non-conventional yeast and freeze-drying a lower layer precipitate.

4. A method according to any one of claims 1-3, characterized in that: the addition amount of the catalyst is 5-30% of the mass of the vegetable oil.

5. The method according to any one of claims 1-4, wherein: the adding mode of the hydrogen peroxide solution is fed-batch, and the feeding rate is 0.5-2 mL/h; the molar ratio of the hydrogen peroxide in the hydrogen peroxide solution to the double bonds in the vegetable oil is (0.5-3) to 1.

6. The method according to any one of claims 1-5, wherein: the addition amount of the free fatty acid is 1 to 10 percent of the mole number of double bonds contained in the vegetable oil; preferably, the free fatty acid comprises one or more of oleic acid, linoleic acid and linolenic acid.

7. The method according to any one of claims 1-6, wherein: in the step B, the temperature of the epoxidation reaction is 15-45 ℃; and/or the stirring speed is above 200 rpm; and/or the epoxidation reaction time is 6-24h, preferably 12-24 h.

8. The method according to any one of claims 1-7, wherein: in the step C, the reaction temperature of the esterification is 25-45 ℃; and/or the stirring speed of the esterification is more than 200 rpm; and/or the reaction time of the esterification is 12-48 h.

9. The method according to any one of claims 1-8, wherein: and D, centrifuging the crude epoxy vegetable oil product to obtain a finished epoxy vegetable oil product, and recycling the lower-layer catalyst for recycling.

10. The method according to any one of claims 1-9, wherein: the vegetable oil comprises one or more of linseed oil, soybean oil, perilla oil, sunflower seed oil, peanut oil and rapeseed oil.

Technical Field

The invention belongs to the field of biochemical engineering, and relates to a method for preparing epoxy vegetable oil by solvent-free cell catalysis.

Background

Traditional petroleum-based phthalate plasticizers are most widely used globally. The yield and consumption of traditional phthalate plasticizers are a large proportion of the total plasticizer yield and sales, but they are increasingly limited due to potential threats to human health and the environment. Strict environmental protection and safety regulations are established and implemented at home and abroad. The development of environmentally friendly non-toxic plasticizers and biodegradable bio-based plasticizers to replace phthalate esters has been a hot point of research. Nontoxic green plasticizers with high stability, oil resistance and migration resistance, which are applied to electrical insulation, food packaging and medical and health care products, are being developed, produced and applied continuously.

The plasticizer is a functional additive, and when the plasticizer is added into a polymer, the secondary valence bond force among molecules is weakened, the crystallinity is reduced, the relative motion among molecular chains is increased, and the plasticity of the material is improved. Thus, plasticizers are used primarily to reduce the hardness, softening temperature, modulus of elasticity and brittle temperature of polymers, while improving their flexibility and elongation. Alternatives to non-phthalate plasticizers currently include primarily citrate esters, phosphate esters, polyesters, halogenated alkanes, and epoxy compounds. Wherein, the epoxy group in the epoxy compound structure can absorb and neutralize the hydrogen chloride released by the PVC in the light or thermal degradation process, delay the continuous decomposition of the PVC, endow the PVC products with good light and heat stability and prolong the service life of the PVC products.

Vegetable oils are receiving wide attention as renewable resources and can be used for producing energy sources, chemicals and the like, and epoxidized vegetable oils have been used on an industrial scale and are widely used as plasticizers and stabilizers for producing polyvinyl chloride (PVC). Epoxidized vegetable oils have high reactivity due to their high content of unsaturated fatty acids, and the high reactivity of the epoxy groups provides the possibility of curing reactions, such as those using polyfunctional amines and anhydrides. Epoxidized soybean oil has been used in the synthesis of new bio-based thermoset resins.

The current process for the epoxidation of vegetable oils is mainly chemical, mainly Prilezhaev epoxidation is applied, short chain peroxy acids are preferred in this reaction, e.g. by acetic acid with hydrogen peroxide (H)₂O₂) And used as a catalyst.

CN 102850298 discloses a method for applying a composite stabilizer for unsaturated fatty acid epoxidation, which takes mixed acid of organic acid and strong acid as a catalyst, and adds a peroxy acid composite stabilizer to catalyze the epoxidation of an unsaturated compound. The method has more types of stabilizers and more complicated separation process in the later period of adding acid.

US 2485160 discloses a process for the epoxidation of oleic acid and linoleate using formic acid as catalyst by adjusting the reaction temperature to control the epoxidation to achieve 88% epoxy conversion for 24h. The reaction product produces waste acid wastewater.

CN 103601703B discloses a method for preparing epoxidized tung oil methyl stearate, which synthesizes epoxidized methyl eleostearate through epoxidation reaction under the action of a solid acid catalyst and organic acid. Highly corrosive waste is produced in the process product.

CN 103224837 discloses a method for rapidly preparing epoxidized soybean oil, wherein a non-aqueous organic solvent, a heteropolyacid phase transfer catalyst and an interfacial activator polyethylene glycol are added into a system, and after the reaction is finished, the organic phase is separated and subjected to vacuum distillation to obtain the epoxidized soybean oil. The method has complicated reaction process and high energy consumption.

The chemical epoxidation method is easy to generate high-corrosivity waste, and is also easy to cause the ring opening of epoxy rings, and the product is polymerized under the acidic condition. Enzymatic catalysis of vegetable oil epoxidation is a widely used method, enzymatic epoxidation having a similar mechanism to the Prilezhaev reaction (acid catalyst), in which the free fatty acid acts as an "acid" instead of the strong acid (acetic acid or formic acid) used in the Prilezhaev reaction. The fatty acid is then converted to a peroxy acid in a peroxidation step, consumed in an epoxidation step, and subsequently converted back to a fatty acid.

The most significant problem with lipase mediated epoxidation is that of H₂O₂To inactivate enzymes, higher double bond content in vegetable oils requires more H₂O₂More hydrogen peroxide is challenging for enzyme activity, requiring higher tolerance of the enzyme.

CN 104894175B discloses a method for preparing epoxy vegetable oil, wherein glycerin is used as a reaction auxiliary agent in the reaction, the viscosity of the reaction system is high, the energy consumption is high, and the later separation step is complicated.

WO/2010/098651 discloses a method for epoxidizing palm oil, in the reaction, Novozyme435 is used as a catalyst to catalyze the epoxidation of palm oil, and toluene is used as a solvent to react for 16 hours, so that the conversion rate is more than 90%, but the reaction process is complicated by using the solvent.

CN105567758B discloses an epoxidation method of fatty acid methyl ester, which uses esterase as a catalyst to catalyze the epoxidation of fatty acid methyl ester to obtain epoxidized fatty acid methyl ester. However, esterases are relatively costly.

Edgardo T Farinas et al, proposed olefin epoxidation catalyzed by cytochrome P450 BM-3139-3, confirming that cytochrome P450 can act as an epoxidation catalyst, but cytochrome P450 is only suitable for laboratory studies and is not suitable for large scale production.

Although the conversion rate of enzymatic catalytic epoxidation is high, a hydrolysis side reaction exists in the reaction process, and the addition of a solvent makes the later process flow complicated, which is not beneficial to later separation. Currently, Novozymes435 is the enzyme most widely used in lipase-mediated chemo-enzymatic epoxidation, but the cost is high and the enzyme cannot be applied industrially. Toluene is a common enzymatic epoxidation solvent, toluene is added in the reaction, the addition amount of the solvent is large, the reaction system is complex, and the later separation step is complicated, so that the industrial production is not facilitated.

Therefore, there is a need to develop a solvent-free enzymatic epoxidation method, which has mild reaction conditions, few byproducts, no pollution, low cost, and is suitable for industrial production.

Disclosure of Invention

The invention aims to solve the technical problem of providing a method for preparing epoxy vegetable oil by solvent-free cell catalysis aiming at the defects in the prior art. The method has the advantages of mild reaction conditions, few byproducts, no pollution and low cost, and is beneficial to industrial production.

Therefore, the invention provides a preparation method for preparing epoxy vegetable oil by solvent-free cell catalysis, which comprises the following steps:

b, mixing the vegetable oil with a catalyst and free fatty acid, adding a hydrogen peroxide solution, stirring, and carrying out an epoxidation reaction to obtain an epoxidation reaction crude product;

step C, carrying out centrifugal treatment on the crude product of the epoxidation reaction, removing a water layer, continuously stirring and mixing an oil layer and the catalyst, and carrying out esterification while vacuumizing to obtain a crude product of the epoxy vegetable oil;

step D, carrying out centrifugal treatment on the crude epoxy vegetable oil product to obtain a finished epoxy vegetable oil product;

wherein the catalyst is thallus of unconventional yeast.

In some embodiments of the invention, the non-conventional yeast comprises one or more of candida citrifolia, candida tropicalis, candida parapsilosis, candida olivaceus, candida rugosa, and yarrowia lipolytica.

According to the invention, the thallus of the unconventional saccharomycetes is obtained by centrifuging a fermentation product of the unconventional saccharomycetes and freeze-drying a lower-layer precipitate.

In some embodiments of the invention, the catalyst is added in an amount of 5% to 30% by mass of the vegetable oil.

In the invention, the adding mode of the hydrogen peroxide solution is fed-batch, and the feeding rate is 0.5-2 mL/h.

In some embodiments of the invention, the molar ratio of hydrogen peroxide in the hydrogen peroxide solution to the double bonds contained in the vegetable oil is (0.5-3) to 1.

According to the invention, the free fatty acid is added in an amount of 1-10% by mole of the double bonds contained in the vegetable oil.

In the invention, the free fatty acid comprises one or more of oleic acid, linoleic acid and linolenic acid.

In some embodiments of the invention, in step B, the temperature of the epoxidation reaction is from 15 to 45 ℃.

In some embodiments of the invention, in step B, the speed of the agitation is above 200 rpm.

In some embodiments of the present invention, in step B, the time for the epoxidation reaction is 6 to 24 hours, preferably 12 to 24 hours.

In some embodiments of the invention, in step C, the reaction temperature of the esterification is from 25 to 45 ℃.

In some embodiments of the invention, in step C, the stirring speed of the esterification is above 200 rpm.

In some embodiments of the invention, in step C, the reaction time for the esterification is 12 to 48 h.

According to some preferred embodiments of the present invention, in step D, the crude epoxidized vegetable oil is centrifuged to obtain a finished epoxidized vegetable oil, and the lower catalyst is recovered for recycling.

In the invention, the vegetable oil comprises one or more of linseed oil, soybean oil, perilla oil, sunflower seed oil, peanut oil and rapeseed oil.

Compared with the prior art, the invention has the following characteristics:

1. in the epoxidation process, the self-produced fermentation thalli is used, and the invention discovers that the thalli has the characteristics of strong esterification and weak hydrolysis, has good hydrogen peroxide tolerance and is an epoxidation catalyst with excellent performance. In the process, the hydrogen peroxide is added in a fed-batch mode, so that the concentration of the hydrogen peroxide in the system is in a stable level, the enzyme activity is favorably maintained, and the epoxy can be continuously carried out. The system is carried out at a low temperature of 15-45 ℃, the energy consumption of the whole reaction system is reduced while the thalli keep high activity, the reaction effect and the generation amount of target products are further improved, and the epoxy conversion rate of the linseed oil prepared by the method reaches more than 80%.

2. After the reaction is finished, a little side reaction hydrolysis occurs, after the water layer is removed by centrifugation, the thalli can continue to catalyze the esterification, and finally, the (esterification) system is basically free of free fatty acid.

3. The invention has the advantages of high selectivity of target products, no solvent addition in the reaction process, mild reaction conditions, few side products, no pollution of products, low cost and contribution to industrial production.

Detailed Description

In order that the invention may be readily understood, reference will now be made in detail to the present invention as illustrated in the accompanying drawings. Before the present invention is described in detail, it is to be understood that this invention is not limited to particular embodiments described. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.

Where a range of values is provided, it is understood that each intervening value, to the extent that there is no stated or intervening value in the stated range, to the stated upper or lower limit and any other stated or intervening value in the stated range, is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included in the smaller ranges, and are also encompassed within the invention, subject to any specifically excluded limit in the stated range. Where a specified range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the invention.

Unless otherwise defined, all terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention, the preferred methods and materials are now described.

I. Detailed description of the preferred embodiments

As mentioned above, chemical epoxidation is prone to generate highly corrosive waste, and also tends to cause the opening of epoxy rings, and the polymerization of the product under acidic conditions. Although the conversion rate of enzymatic catalytic epoxidation is high, a hydrolysis side reaction exists in the reaction process, and the addition of a solvent makes the later process flow complicated, which is not beneficial to later separation. At present, the lipase-mediated chemical-enzymatic epoxidation reaction has high cost and cannot be industrially applied, and toluene is used as a common enzymatic epoxidation solvent, so that the addition amount in the reaction is large, the reaction system is complex, and the later separation step is complicated, thereby being not beneficial to industrial production. In view of this, the present inventors have conducted extensive studies on the process for producing epoxy vegetable oil.

The inventor researches and discovers that the fermentation thalli of candida plicata, yarrowia lipolytica and the like have the characteristics of strong esterification and weak hydrolysis, have good hydrogen peroxide tolerance and are epoxidation catalysts with excellent performance. The zymophyte of the yeast is used as the vegetable oil epoxidation catalyst, so that the vegetable oil epoxidation reaction can be carried out under the condition of no solvent, and the method has the advantages of mild reaction condition, less byproducts, no pollution, low cost and contribution to industrial production. The present invention has been completed based on the above findings.

Therefore, the method for preparing the epoxidized vegetable oil by the solvent-free cell catalysis comprises the following steps:

step B, mixing the vegetable oil with the catalyst and the free fatty acid under the stirring condition, adding a hydrogen peroxide solution, and carrying out an epoxidation reaction to obtain an epoxidation reaction crude product;

step C, carrying out centrifugal treatment on the crude product of the epoxidation reaction, removing a water layer, continuously mixing an oil layer and the catalyst under the stirring condition, and carrying out esterification while vacuumizing to obtain a crude product of the epoxy vegetable oil;

and D, carrying out centrifugal treatment on the crude epoxy vegetable oil product to obtain a finished epoxy vegetable oil product.

As described above, the present inventors have found that fermented cells of Candida rugosa, yarrowia lipolytica, and the like are excellent in the esterification property and the hydrolysis property, and also have good hydrogen peroxide tolerance, and are excellent epoxidation catalysts. The zymophyte of the yeast is used as the vegetable oil epoxidation catalyst, so that the vegetable oil epoxidation reaction can be carried out under the condition of no solvent, and the method has the advantages of mild reaction condition, less by-products, no pollution and low cost. Therefore, in the present invention, the catalyst is a cell of an unconventional yeast.

Specifically, the non-conventional yeast includes Candida citricola (e.g., Candida citricola having a strain preservation number of CGMCC 2.2051 or CGMCC 2.1771), Candida tropicalis (e.g., Candida tropicalis having a strain preservation number of CGMCC 2.3967, CGMCC 2.1368, CGMCC 2.1365 or CGMCC 2.1202), Candida parapsilosis (e.g., Candida parapsilosis having a strain preservation number of CGMCC 2.1286, CGMCC 2.1354, CGMCC 2.1637, CGMCC 2.1740 or CGMCC 2.3921), Candida utilis (e.g., Candida oleophila) (e.g., Candida utilis having a strain preservation number of CGMCC 2.1734, CGMCC 2.1735, CGMCC 2.1736, CGMCC 2.1737 or CGMCC 2.1738), Candida rugosa (e.g., Candida rugosa) (e.g., CGMCC2.2937, CGMCC 2.2940, CGMCC 4642 or yarrowia lipolytica), or Candida rugosa (e.g., a Candida rugosa) (e.g., Candida rugosa, CGMCC2.3062 or yarrowia lipolytica (e.g., CGMCC 4642, or yarrowia lipolytica), the strain preservation number is one or more of CGMCC2.1556, CGMCC2.1319, and CGMCC2.1300 yarrowia lipolytica yeast).

According to the invention, the thallus of the unconventional yeast is obtained by centrifuging the fermentation product of the unconventional yeast and freeze-drying the lower-layer precipitate.

In some embodiments of the invention, the catalyst is added in an amount of 5% to 30%, preferably 30%, by mass of the vegetable oil.

The inventor of the invention considers that in the process of plant oil oxidation, firstly, aiming at the problems that the demand of hydrogen peroxide is high due to the fact that the content of unsaturated fatty acid in plant oil is high and the double bond content is high, the high content of hydrogen peroxide inevitably tests the activity of enzyme, and the maintenance of the activity of the enzyme in the reaction is important. And secondly, the generation of side reaction, namely the hydrolysis of triglyceride is reduced, so that the reaction process is simpler and more convenient, and the recovery of later-stage reaction is facilitated. Therefore, in the reaction process of the step B of the invention, the hydrogen peroxide is added in a fed-batch manner, and the fed-batch rate is 0.5-2mL/h, so that the concentration of the hydrogen peroxide in the system is in a stable level, which is beneficial to maintaining enzyme activity and enabling the epoxy to be continuously carried out.

In some embodiments, the hydrogen peroxide solution is flowed with a syringe pump after the system has stabilized for 5 minutes. As used herein, "system stable" means that the temperature of the feed is raised to a set value (i.e., the epoxidation reaction temperature).

In some embodiments of the present invention, the molar ratio of hydrogen peroxide in the hydrogen peroxide solution to the double bonds contained in the vegetable oil is (0.5-3) to 1, preferably (1-2) to 1, and more preferably 1: 1.

The concentration of the hydrogen peroxide solution in the present invention is not particularly limited as long as the blending ratio of hydrogen peroxide to the double bonds contained in the vegetable oil can be satisfied, and for example, a commercially available hydrogen peroxide solution having a concentration of 30 wt% can be used.

According to the method of the invention, in the step B, the stirring speed is more than 200rpm, and the temperature of the epoxidation reaction is 15-45 ℃, preferably 25-35 ℃; the time for the epoxidation reaction is 6 to 24 hours, preferably 12 to 24 hours, and more preferably 12 hours.

The inventor researches and discovers that the epoxidation reaction is carried out at a low temperature of 20-40 ℃, so that the energy consumption of the whole reaction system is reduced while the activity of bacteria is kept high, the reaction effect and the yield of a target product are further improved, and the epoxy conversion rate of the linseed oil prepared by the invention is over 80 percent.

It is easily understood that the free fatty acid plays a role in mediating the oil epoxidation reaction of the vegetable during the epoxidation reaction of step B, and the amount of the free fatty acid added is 1% to 10%, preferably 5% to 10%, and more preferably 5% of the number of moles of double bonds contained in the vegetable oil.

In the present invention, the source of the free fatty acid is not particularly limited, and for example, commercially available or self-made free fatty acids can be used.

In the invention, the free fatty acid comprises one or more of oleic acid, linoleic acid and linolenic acid, preferably oleic acid or a mixture of oleic acid, linoleic acid and linolenic acid, and the mass ratio of the oleic acid to the linoleic acid to the linolenic acid in the mixture of the oleic acid, the linoleic acid and the linolenic acid is (1-2): 1-5), preferably 2: 5.

In step C of the invention, a little side reaction hydrolysis occurs after the reaction is finished, and after the water layer is removed by centrifugation, the thalli can continue to catalyze the esterification, and finally, the system is basically free of free fatty acid.

According to the invention, in step C, the stirring speed of the esterification is above 200rpm, preferably 200 rpm; the reaction temperature of the esterification is 25-45 ℃, preferably 25-40 ℃, and further preferably 40 ℃; the reaction time of the esterification is 12 to 48 hours, and 48 hours is preferred.

In some preferred embodiments of the present invention, in step D, the crude epoxidized vegetable oil is centrifuged to obtain a finished epoxidized vegetable oil, and the lower catalyst is recovered for recycling. The test results show that the fungus body of the unconventional yeast used as the catalyst in the present invention can be recycled after being recovered, and can be recycled more than 3 times.

In the invention, the vegetable oil comprises one or more of linseed oil, soybean oil, perilla oil, sunflower seed oil, peanut oil and rapeseed oil.

The terms "yeast" and "yeast" are used interchangeably herein.

In some embodiments of the present invention, the preparation of epoxidized vegetable oil by using thallus of yarrowia lipolytica as catalyst comprises the following steps:

(1) the fermentation product of yarrowia lipolytica is centrifuged, the sediment at the lower layer is frozen and dried to obtain thalli, the thalli is used as a catalyst, the catalyst thalli is the fermentation product of yarrowia lipolytica, the fermentation product has the characteristics of strong esterification activity and weak hydrolysis activity, and the hydrolysis activity is inhibited by the reaction under the low-temperature condition. The invention discovers that the thallus has stronger esterification activity and weaker hydrolysis activity, simultaneously has good epoxidation catalytic performance, has good tolerance to hydrogen peroxide and has low cost.

(2) Adding hydrogen peroxide with a certain concentration and thalli into vegetable oil to carry out epoxidation reaction, wherein the process is a cell catalytic epoxidation process, the reaction time is 6-24h, the reaction is carried out in a low-temperature environment, and after the reaction is finished, a crude epoxidation product is obtained.

(3) And (3) centrifuging the crude product of the epoxy vegetable oil, removing a water layer, continuously mixing an oil layer and the thalli, vacuumizing and esterifying to obtain the epoxy vegetable oil basically free of free acid, recovering the thalli, freeze-drying and recycling.

The temperature of the epoxidation reaction in the step (2) is 15-45 ℃, the stirring speed is more than 200rpm, and the reaction time is 6-24h.

The concentration of the hydrogen peroxide is 30 percent, the adding mode is fed-batch, the adding speed is 0.5-2mL/h, and the molar ratio of the hydrogen peroxide to double bonds in the vegetable oil is 0.5: 1-3: 1.

The catalyst thallus is added at one time, and the adding amount of the catalyst thallus is 5-30% of the mass of the vegetable oil.

The addition amount of the free fatty acid is 1 to 10 percent of the mole number of double bonds contained in the vegetable oil.

The esterification reaction in the step (3) has the temperature of 25-45 ℃, the stirring speed of more than 200rpm and the reaction time of 12-48 h.

And centrifuging after the esterification is finished to obtain epoxy vegetable oil, and separating the lower-layer thalli for recycling.

The related parameter detection and calculation method in the invention is as follows:

(1) the method for measuring the double bond content in the vegetable oil comprises the following steps:

methyl-esterifying the vegetable oil, performing gas phase analysis by using a Saimerfi TRACE1300 gas chromatograph (RTX-WAX chromatographic column) to obtain the relative contents of different types of fatty acids in the vegetable oil, further obtaining the total double bond mole number in the vegetable oil, namely,

wherein w is the vegetable oil molecular weight; a is the oleic acid content; b is the linoleic acid content; c is the linolenic acid content; and 92 is glycerol molecular weight.

(2) The epoxide number is determined by reference to the determination of the epoxide number of the GB1677-81 plasticizer.

Wherein V is the amount of the sodium hydroxide standard solution consumed in the blank test, and the unit is mL;

V₁the amount of sodium oxide standard solution consumed for the sample test; the unit is mL;

V₂the amount of the sodium hydroxide standard solution consumed for measuring the acid value in the sample is mL;

n is the equivalent concentration of the sodium hydroxide standard solution, and the unit is mol/L;

w sample weight in g;

g is the weight of the sample in G when the acid value is measured;

0.016 is the oxygen meq.

(3) The double bond conversion is theoretically calculated according to the following formula:

in the above formula:

the amount of material having a double bond content equal to the oxygen content of the epoxy number, in mol;

the theoretical double bond content, namely the total double bond content in the vegetable oil, is obtained by the related parameter detection and calculation method involved in the invention, namely the determination method of the double bond content in the vegetable oil (1), and the unit is mol.

Example II

In order that the present invention may be more readily understood, the following detailed description will be given with reference to the accompanying examples, which are given by way of illustration only and are not intended to limit the scope of the invention. The raw materials or components used in the present invention can be obtained commercially or by conventional methods unless otherwise specified.