CN112521988B

CN112521988B - Biodiesel antioxidant composition and preparation method and application thereof

Info

Publication number: CN112521988B
Application number: CN201910878370.8A
Authority: CN
Inventors: 蔺建民; 李宝石; 李妍
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2019-09-18
Filing date: 2019-09-18
Publication date: 2022-10-21
Anticipated expiration: 2039-09-18
Also published as: CN112521988A

Abstract

The invention provides a biodiesel antioxidant composition and a biodiesel composition. The antioxidant composition contains a component a and a component b, wherein the component a is a bisphenol antioxidant and/or a polyphenol antioxidant containing at least two phenolic hydroxyl groups on a benzene ring; the component b is alkenyl ester-based succinimide or/and alkenyl ester-based succinamide. The antioxidant composition can improve the oxidation stability of the biodiesel and has good solubility in the biodiesel.

Description

Biodiesel antioxidant composition and preparation method and application thereof

Technical Field

The invention relates to a fuel oil additive, in particular to a biodiesel antioxidant composition, a preparation method and application thereof.

Background

With the acceleration of the trend of vehicle diesel oil production in the world, the demand of diesel oil is getting bigger and bigger, and the increasing exhaustion of petroleum resources and the improvement of environmental awareness of people greatly promote the pace of accelerating the development of diesel oil substituted fuels in all countries in the world, and the biodiesel receives attention from all countries due to the excellent environmental protection performance and reproducibility thereof.

Biodiesel (BD 100), also known as Fatty Acid Methyl Ester (Fatty Acid Methyl Ester), is prepared by using oil crops such as soybean and rapeseed, oil trees such as oil palm and pistacia chinensis, oil of oil plants such as engineering microalgae, oil of aquatic plants such as animal oil and waste cooking oil as raw materials, and performing transesterification reaction on the raw materials and alcohols (methanol and ethanol), and is a clean biofuel. The biodiesel has the advantages of reproducibility, cleanness and safety, and has great strategic significance for agricultural structure adjustment, energy safety and ecological environment comprehensive treatment in China.

However, some biodiesel has poor oxidation stability due to raw materials and processing techniques, and thus causes great difficulty in use and storage of biodiesel. Biodiesel with poor oxidation stability is prone to generate the following aging products: 1) Insoluble polymers (gums and sludge), which can cause clogging of the engine screens and coking of the jet pumps, and lead to increased smoke emissions, difficult start-up; 2) Soluble polymers, which can form resinous species in the engine, can lead to misfire and start-up difficulties; 3) Aging the acid, which can cause corrosion of engine metal parts; 4) Peroxides, which can cause aging of rubber parts to become brittle, resulting in fuel leakage, etc.

European biodiesel Standard EN 14214, ASTM International organization for biodiesel Standard ASTM D6751, and national Standard GB 25199 of "B5 Diesel" in China all have strict requirements on the oxidation stability of biodiesel.

CN1742072A discloses a method for improving the storage stability of biodiesel, which comprises adding a liquid stock solution containing 15-60 wt% of 2, 4-di-tert-butylhydroxytoluene dissolved in biodiesel, based on the stock solution, to the biodiesel to be stabilized until the concentration of 2, 4-di-tert-butylhydroxytoluene reaches 0.005-2 wt% based on the total solution of biodiesel.

CN1847368A discloses a method for improving the oxidation stability of biodiesel, which comprises adding bisphenol type antioxidants such as 4,4 '-methylenebis [2, 6-di-tert-butylphenol ], 2' -methylenebis [ 6-tert-butyl-4-methylphenol ] in an amount of 10-20000ppm (w/w) to the biodiesel to be stabilized.

CN1847369A discloses a method for improving the oxidation stability of biodiesel, which comprises adding a primary antioxidant having a melting point of 40 ℃ or less to the biodiesel to be stabilized in an amount of 10-20000ppm (w/w), wherein the primary antioxidant contains alkylphenol.

US2007/113467A1 discloses a fuel composition with improved oxidation stability comprising biodiesel and at least one antioxidant selected from one of propyl gallate, 1,2, 3-trihydroxybenzene, 2, 6-di-tert-butyl-p-methylphenol, butylated hydroxyanisole, lauryl thiodipropionate, tocopherol, quinoline derivatives.

Although the conventional method for improving the oxidation stability of biodiesel by using the antioxidant has a certain effect, most of the conventional methods are solid antioxidants which are difficult to dissolve in the biodiesel, and the improvement effect on the oxidation stability of the biodiesel produced by using waste oil as a raw material is limited.

CN101928614A discloses that a phenolic antioxidant is compounded with a polyamine compound to be used as a biodiesel antioxidant, and CN101993743A discloses that a polyphenol antioxidant is compounded with an amination product of a hydrocarbyl dicarboxylic acid, an anhydride or a half ester compound to be used as a biodiesel antioxidant. The polyamine compound has strong polarity and strong alkalinity, and can easily generate fatty acid ammonium salt with fatty acid and be separated out in the biodiesel. The aminated product of the hydrocarbyl dicarboxylic acid, anhydride or half-ester compound has poor solubility in biodiesel, and the biodiesel is easily turbid.

CN04371772A discloses that the polyphenol antioxidant is used in combination with an amination product of an aminopolyacid as a biodiesel antioxidant, wherein unreacted aminopolyacid or polyamine compounds are remained in the amination reaction of the aminopolyacid, and the unreacted aminopolyacid is difficult to treat and has poor solubility in biodiesel.

Disclosure of Invention

The invention aims to overcome the defect of poor solubility of the antioxidant in the biodiesel in the prior art, and provides an antioxidant composition which can improve the oxidation stability of the biodiesel and has good solubility.

The invention also provides a preparation method of the antioxidant composition for the biodiesel.

The invention also provides a biodiesel composition containing the antioxidant composition.

The invention also provides a diesel oil composition containing the antioxidant composition.

In a first aspect, the invention provides an antioxidant composition for biodiesel, which comprises a component a and a component b, wherein the component a is a bisphenol type antioxidant and/or a polyphenol type antioxidant containing at least two phenolic hydroxyl groups on a benzene ring; the component b is alkenyl ester-based succinimide shown in a structural formula b1 or/and alkenyl ester-based succinamide shown in a structural formula b 2:

wherein R is ₁ 、R ₂ Is a hydrocarbon radical with or without double bonds, R ₁ And R ₂ Has a total carbon number of 8 to 24, preferably 12 to 22, more preferably 16 to 20, a total degree of unsaturation (total number of double bonds) of 0, 1 or 2, R ₃ Is a C1-C4 hydrocarbon group, preferably methyl or ethyl; r is ₄ A group containing at least one nitrogen atom which is C2-C30, preferably C2-C20.

The mass ratio of the component a to the component b in the antioxidant composition is 1.02-50, preferably 1.

Component a

The component a is a bisphenol antioxidant and/or a polyphenol antioxidant containing at least two phenolic hydroxyl groups on a benzene ring. In the invention, the bisphenol antioxidant is bisphenol formed by connecting two monophenols, and can be one or more of the following:

4,4' -isopropylidene bisphenol (bisphenol a);

2,2' -bis- (3-methyl-4 hydroxyphenyl) propane (bisphenol C);

4,4' -dihydroxybiphenyl (antioxidant DOD);

4,4' -dihydroxy-3, 3', 5' -tetra-tert-butylbiphenyl (antioxidant 712);

2,2' -methylene-bis- (4-methyl-6-tert-butylphenol) (antioxidant 2246);

4,4' -methylene-bis- (2-methyl-6-tert-butylphenol) (antioxidant methylene 736);

2,2' -methylene-bis- (4-ethyl-6-tert-butylphenol) (antioxidant 425);

2,2' -methylene-bis- (4-methyl-6-cyclohexylphenol) (antioxidant ZKF);

2,2' -methylene-bis [ 4-methyl-6- (. Alpha. -methylcyclohexyl) phenol ] (antioxidant WSP);

2,2' -methylene-bis- (6- α -methylbenzyl-p-cresol);

4,4' -methylene-bis- (2, 6-di-tert-butylphenol) (antioxidant T511);

4,4' -methylene-bis- (2-tert-butylphenol) (antioxidant 702);

2,2' -ethylene-bis- (4-methyl-6-tert-butylphenol);

4,4' -ethylene-bis- (2-methyl-6-tert-butylphenol);

4,4' -ethylene-bis- (2, 6-di-tert-butylphenol);

4,4' -butylidene-bis- (6-tert-butyl-m-cresol) (antioxidant BBM, antioxidant TCA);

4,4' -isobutylidene-bis- (2, 6-di-tert-butylphenol), and the like.

N, N' -hexamethylene bis- (3, 5-di-tert-butyl-4-hydroxy hydrocinnamamide) (antioxidant 1098);

hexanediol bis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ] (antioxidant 259);

bis- (3, 5-di-tert-butyl-4-hydroxyphenylpropionic acid propionyl) hydrazine (antioxidant BPP);

2,2' -thiodiglycol bis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ] (antioxidant 1035);

triethylene glycol bis-3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate (antioxidant 245), and the like.

The bisphenol-type antioxidant is preferably a bisphenol in which two monophenols having at least one tert-butyl group ortho to the phenolic hydroxyl group are linked via a methylene group, for example one or more of the following:

2,2' -methylene-bis- (4-methyl-6-tert-butylphenol) (antioxidant 2246);

4,4' -methylene-bis- (2-methyl-6-tert-butylphenol) (antioxidant methylene 736);

4,4' -methylene-bis- (2, 6-di-tert-butylphenol) (antioxidant T511);

4,4' -methylene-bis- (2-tert-butylphenol) (antioxidant 702);

the polyphenol antioxidant refers to phenol containing at least two phenolic hydroxyl groups on the same benzene ring in the same phenol antioxidant molecule, such as one or more of the following substances:

tert-butyl hydroquinone, di-tert-butyl hydroquinone, pyrogallic acid, C1-C18 esters of gallic acid, such as methyl gallate, ethyl gallate, propyl gallate, butyl gallate, pentyl gallate, hexyl gallate, heptyl gallate, octyl gallate, nonyl gallate, decyl gallate, dodecyl gallate, tetradecyl gallate, hexadecyl gallate, octadecyl gallate, octadecenyl gallate, etc.

The polyphenol type antioxidant is preferably tert-butylhydroquinone (TBHQ) and C1-C18 esters of gallic acid, especially Propyl Gallate (PG).

Component b

The component b is alkenyl ester group succinimide shown in a structural formula b1 or/and alkenyl ester group succinamide shown in a structural formula b 2:

wherein, the compounds shown in the structural formulas b1 and b2 can be in any proportion.

Wherein R is ₁ 、R ₂ Is a hydrocarbon radical with or without double bonds, R ₁ And R ₂ Has a total carbon number of from 8 to 24, preferably from 12 to 22, more preferably from 16 to 20, and a total degree of unsaturation (total number of double bonds) of 0, 1 or 2, for example R ₁ And R ₂ May be alkyl, alkenyl, hydroxyalkyl, hydroxyalkenyl, dienyl, and the like; r ₃ Is a C1-C4 hydrocarbon group, preferably methyl or ethyl; r is ₄ The group containing at least one nitrogen atom is C2-C30, preferably C2-C20, and may contain a functional group such as a carbonyl group, a hydroxyl group, a carboxyl group, an ester group, an acyl group, an alkoxy group, an amine group, or an amino group.

In a second aspect, the invention provides a preparation method of the antioxidant composition for biodiesel, which comprises the following steps: mixing the component a and the component b, wherein the preparation method of the component b comprises the following steps:

3) Performing addition reaction on a raw material containing C8-C24 unsaturated fatty acid alkyl ester and maleic anhydride to obtain alkenyl succinic anhydride;

4) And carrying out amination reaction on the alkenyl succinic anhydride and a polyamine compound to obtain alkenyl succinimide or/and alkenyl succinamide.

In the step 1), the reaction molar ratio of the C8-C24 unsaturated fatty acid alkyl ester to the maleic anhydride is between 1 and 0.5, preferably between 1 and 2. The reaction can be carried out at a temperature of 150-280 ℃, preferably at a temperature of 180-240 ℃. The reaction time is generally 1 to 20 hours, preferably 6 to 12 hours. The reaction can be catalyzed by acid such as sulfuric acid, p-toluenesulfonic acid, aluminum chloride and the like; it is also possible, and preferably not, to use a catalyst.

In step 2), the amination reaction can be carried out at a temperature of 40 to 280 ℃, preferably at a temperature of 60 to 180 ℃. The reaction time is generally 0.5 to 10 hours, preferably 1 to 8 hours. The reaction can be carried out by using an acid catalyst, such as one or more of aluminum chloride, sulfuric acid, hydrochloric acid, boron trifluoride, solid super acid, cation exchange resin, heteropoly acid and the like; basic catalysts such as sodium hydroxide, potassium hydroxide, sodium methoxide, etc.; it is also possible, and preferably not, to use a catalyst.

The molar ratio of the alkenyl succinic anhydride to the polyamine compound may be 1. The reaction product of the alkenyl succinic anhydride and the polyamine compound is related to the reaction temperature and the molar ratio of the reactants, and specifically, the following conditions are provided:

1) When the reaction temperature is low (e.g., about 100 ℃) and the polyamine is not excessive, a product mainly composed of the monoamide represented by the formula 3 is produced. Monoamides are less preferred in the present invention because of their higher acidity. If the polyamine is in excess, the carboxyl groups in formula 3 can react further to form a bisamide compound based on formula 2. Therefore, at a lower reaction temperature, it is preferable to use a suitable excess of polyamine, for example, the molar ratio of alkenyl succinic anhydride to polyamine compound may be 1.

2) When the reaction temperature is relatively high (for example, about 150 ℃) and the molar ratio of the alkenyl succinic anhydride to the polyamine compound is close to 1. If the alkenyl succinic anhydride is in excess, two or more succinic acids and/or succinic anhydrides will react with the same polyamine to form so-called "di-pendant" or "poly-pendant" reaction products. Thus, at higher reaction temperatures, a suitable excess of polyamine is preferred, for example, the molar ratio of alkenyl succinic anhydride to polyamine compound may be 1 to 2, i.e., a "single-pendant" based reaction product of formula 1 is produced.

3) Regardless of the reaction temperature, if the polyamine is excessive, the excessive polyamine can further undergo aminolysis reaction with the compound of formula 1 and formula 2 to react R ₃ And removed in the form of an alcohol to produce an imide-amide compound or a triamide compound.

According to the process of the present invention, in step 1) and step 2), a reaction solvent such as toluene, xylene, ethylbenzene, a heavy aromatic solvent, etc., may be further added as necessary.

In the raw material containing the C8-C24 unsaturated fatty acid alkyl ester, the unsaturated fatty acid can be C8-C24 long-chain olefine acid containing one, two or three double bonds and containing or not containing hydroxyl, and the alkyl ester can be C1-C4 alkyl ester. The unsaturated fatty acid alkyl esters are preferably C12 to C22 unsaturated fatty acid methyl and ethyl esters, more preferably C16 to C20 unsaturated fatty acid methyl esters, such as methyl palmitoleate (C16 enoate), methyl oleate (C18 enoate), methyl ricinoleate (hydroxy-containing C18 enoate), methyl linoleate (C18 dienoate), methyl linolenate (C18 trienoate), methyl arachidonate (C20 enoate), methyl erucate (C22 enoate), and the like, with the most preferred examples being methyl oleate, methyl linoleate, and methyl ricinoleate and mixtures thereof.

The feedstock containing C8-C24 unsaturated fatty acid alkyl esters is also preferably biodiesel, the chemical composition of which is fatty acid monoalkyl esters, primarily C8-C24 fatty acid methyl esters, containing unsaturated fatty acid methyl esters, and the invention is preferably biodiesel having a high content of unsaturated fatty acid methyl esters, e.g., biodiesel having an unsaturated fatty acid methyl ester content of greater than 60%, preferably greater than 80%. The biodiesel with high content of unsaturated fatty acid methyl ester can be biodiesel produced by grease raw materials with high content of unsaturated fatty acid, and can also be biodiesel with high content of unsaturated fatty acid methyl ester obtained by removing saturated fatty acid methyl ester in the biodiesel through reduced pressure distillation and/or low-temperature freezing crystallization.

The polyamine compound refers to a hydrocarbyl amine containing two or more nitrogen atoms in the molecule, wherein at least one hydrogen atom is bonded to a nitrogen atom.

The polyamine may be a hydrocarbyl diamine of formula H ₂ N-R ₅ -NHR ₆ Wherein R is ₅ May be a hydrocarbon group having 2 to 30 carbon atoms, preferably 4 to 22 carbon atoms, such as an alkylene group, an alkenyl group, a cycloalkyl group, an aryl group, a polyether group or the like; r ₆ May be hydrogen, a hydrocarbon group having a carbon number of 1 to 30, preferably 4 to 22, such as ethylenediamine, propylenediamine, butylenediamine, pentylenediamine, hexylenediamine, heptylenediamine, octylenediamine, decylenediamine, coco-1, 3-propylenediamine, oleyl-1, 3-propylenediamine, tallow-1, 3-propylenediamine, etc.

The polyamine compound can also be a polyene polyamine with the structural formula H ₂ N[(CH ₂ ) _x2 NH] _y1 R ₇ Wherein x2 may be an integer of 2 to 4, preferably 2 or 3, y1 may be an integer of 1 to 8, R ₇ May be hydrogen or a hydrocarbon group having 1 to 30 carbon atoms. For example, when R is ₇ When the polyenylpolyamine is H, the polyenylpolyamine can be one or more of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexaethyleneheptamine, heptaethyleneoctamine, propylenediamine, dipropylenetriamine, triacrylate-tetramine, tetrapropylenepentamine, pentapropylenehexamine, hexapropyleneptamelamine, and heptapropylenoctamine. When R is ₇ In the case of a hydrocarbon group having 1 to 30 carbon atoms, a hydrocarbon group having 4 to 22 carbon atoms is preferred. The hydrocarbon group may be a saturated alkyl group, an alkenyl group having a double bond, or an aryl group having a benzene ring. The alkyl group can be a straight-chain normal alkyl group or an isomeric alkyl group with a side chain, and the alkyl group can be n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tetradecyl, n-hexadecyl, n-octadecyl, n-eicosyl or n-docosyl; isobutyl, tert-butyl, isopentyl, neopentyl, isohexyl, isoheptyl, isooctyl (2-ethylhexyl), isononyl, isodecyl, isododecyl, isotetradecyl, isohexadecyl, isooctadecyl and isodidodecylOne or more of decyl. Examples of alkenyl groups include 9-octadecenyl. The aryl group with benzene ring can be one or more of benzyl, phenethyl and phenylpropyl. Wherein R is ₇ More preferably hydrogen or C6-C20 alkyl.

The polyamine compound may also be an amine containing a nitrogen heterocycle, including but not limited to one or more of an imidazoline type, a piperazine type, and a piperidine type amine.

The imidazoline type polyamine is represented by structural formula 4:

wherein y2 is an integer of 0 to 5, R ₇ The structure is as described above.

The piperazine polyamine is represented by structural formula 5:

wherein R is ₈ Is H or C1-C24 alkyl, and x3 is an integer of 0-5. A preferred typical piperazine-type polyamine is N- (2-aminoethyl) piperazine.

Polyamines of the piperidine type such as 4-amino-2, 6-tetramethylpiperidine, 4-amino-1, 2, 6-pentamethylpiperidine and the like.

The polyamine can also be polyamine containing tertiary amine as shown in structural formula 6 and structural formula 7.

Wherein R is ₉ 、R ₁₀ Is a C1-C10, preferably C1-C4, hydrocarbon group, and x4 is an integer of 0-10, preferably 1-8. For example, one or more of N, N-dimethyl-1, 3-propanediamine, N-diethyl-1, 3-propanediamine, N-dimethyl-1, 4-butanediamine, N-diethyl-1, 4-butanediamine, and N, N-dimethyl-1, 6-hexanediamine.

Wherein x5 is an integer from 1 to 10, preferably an integer from 2 to 6, for example tris (2-aminoethyl) amine.

The polyamine may also be of the formula H ₂ N[(CH ₂ ) _x2 NH] _y1 R ₆ The condensate of the polyene polyamine with ethylene oxide and propylene oxide. Wherein x2 may be an integer from 2 to 4, preferably 2 or 3, y1 may be an integer from 1 to 8, R ₆ May be hydrogen or a hydrocarbon group having 1 to 30 carbon atoms, preferably 4 to 22 carbon atoms.

The polyamine is preferably one or more of the above-mentioned polyene polyamine, imidazoline type, piperazine type and piperidine type amine, and particularly preferably one or more of polyene polyamine and piperazine type polyamine.

Preferably, the antioxidant provided by the invention can also contain various metal deactivators capable of reacting with the metal surface and/or metal chelating agents capable of reacting with or binding with metals or metal ions. The weight ratio of the antioxidant to the sum of the metal deactivator and the chelating agent may be 1.

Specifically, the metal deactivator or metal chelator may be one or more of benzotriazole and its derivatives, thiadiazole and its derivatives, 8-hydroxyquinoline, ethylenediaminetetraacetic acid, hydrazide, β -diketone, β -ketoester, schiff bases (Schiff bases), organic polycarboxylic acid and its derivatives. Since benzotriazole itself is not very excellent in solubility in biodiesel, in order to increase its solubility in biodiesel, benzotriazole is generally modified mainly by introducing an oil-soluble group such as a long-chain hydrocarbon group into benzotriazole. Therefore, the benzotriazole derivative can be various derivatives having better solubility in biodiesel than benzotriazole itself. Specifically, the benzotriazole derivative can be one or more of ammonium salt formed by benzotriazole and fatty amine and a product obtained by Mannich reaction of benzotriazole, formaldehyde and fatty amine. The ethylenediaminetetraacetic acid may be ethylenediaminetetraacetic acid (EDTA) and the hydrazide may be N-salicylidene-N '-salicyloyl dihydrazide and/or N, N' -diacetyladipoyl dihydrazide. Such as acetylacetone and beta-keto esters such as octyl acetoacetate. The Schiff base can be one or more of N, N ' -bis (salicylidene) -1, 2-ethylenediamine, N ' -bis (salicylidene) -1, 2-propanediamine, N ' -bis (salicylidene) -1, 2-cyclohexanediamine and N, N ' -bis (salicylidene) -N ' -methyldipropylenetriamine. The organic polycarboxylic acid and its derivatives may be one or more of citric acid, tartaric acid, malic acid, succinic acid (succinic acid), maleic acid, phytic acid, etc. and their derivatives.

In a third aspect, the invention also provides a biodiesel composition, which comprises biodiesel and the antioxidant composition.

According to the biodiesel composition provided by the invention, the content of the antioxidant composition can be selected in a wide range, for example, relative to the mass of the biodiesel, the content can be 50-5000mg/kg, preferably 80-4000mg/kg, and further preferably 100-3000 mg/kg.

In a fourth aspect, the present invention also provides a diesel oil composition, which comprises biodiesel oil, petroleum diesel oil and the antioxidant composition of the present invention.

In the diesel oil composition provided by the invention, the content of the antioxidant composition can be selected in a wide range, for example, relative to the mass of the biodiesel, the content can be 50-5000mg/kg, preferably 80-4000mg/kg, and further preferably 100-3000 mg/kg.

According to the using requirement, the diesel oil composition provided by the invention can also contain one or more of other additives, such as a flow improver, a cetane number improver, an antistatic agent, a preservative, an antirust agent, a demulsifier and the like.

In the diesel oil composition provided by the invention, the mass ratio of the biodiesel to the petroleum diesel oil can be 1.

The petrochemical diesel oil can be distillate with the distillation range of 160-380 ℃ after crude oil (petroleum) is processed by various refining processes of an oil refinery, such as atmospheric and vacuum distillation, catalytic cracking, catalytic reforming, coking, hydrofining, hydrocracking and the like, and the fuel for the compression ignition type internal combustion engine is prepared and meets the national standard GB/T19147 of the automotive diesel oil.

The biodiesel refers to grease and low-carbon alcohol (such as C) ₁ -C ₅ Fatty alcohol) is subjected to transesterification (alcoholysis) to generate fatty acid lower alcohol ester, generally fatty acid methyl ester, namely the transesterification product of grease and methanol. The transesterification reaction process may be any known or unknown process for obtaining biodiesel through transesterification of fats and oils with lower alcohols, such as acid catalysis, base catalysis, enzyme catalysis, supercritical method, etc. Reference is made in particular to CN1473907A, DE3444893, CN1472280A, CN1142993C, CN1111591C, CN1594504A and the like. The oil and fat have a general meaning well known in the art, and are a generic term for oils and fats, and the main component is fatty acid triglyceride. Generally, oil is a liquid at normal temperature, and fat (fat for short) is a solid or semisolid at normal temperature. The grease comprises vegetable oil and animal oil, and in addition, oil from microorganisms, algae and other substances, and even waste grease, such as used grease or deteriorated grease in waste cooking oil, waste cooking oil production, swill oil, acidified oil of grease factories and the like. The vegetable Oil may be herbal or woody vegetable Oil, such as peanut Oil, corn Oil, cotton seed Oil, rapeseed Oil, soybean Oil, palm Oil, safflower Oil, linseed Oil, coconut Oil, oak Oil, almond Oil, walnut Oil, castor Oil, sesame Oil, olive Oil, tall Oil (Tall Oil), sunflower Oil, jatropha Oil, tung Oil, shinyleaf yellowhorn Oil, pistacia chinensis Oil, oil of saline soil plants such as Kosteletzkya virginica, cyperus esculenta, etc. The animal oil can be lard, chicken oil, duck oil, goose oil, mutton fat, horse oil, beef tallow, whale oil, shark oil, etc.

The antioxidant composition adopts the cooperation of the component a and the component b, and the oxidation stability of the biodiesel is much better than the sum of the effects of the component a and the component b which are used independently, which shows that the components a and b have obvious synergistic action. The antioxidant composition of the invention has good solubility in biodiesel.

Drawings

FIG. 1 is a mass spectrum of an alkenyl succinic anhydride product obtained by addition reaction of methyl oleate and maleic anhydride in preparation example 1.

Wherein the peak at m/z =417.494 is the sodium ion mass spectrum addition peak of the product alkenyl succinic anhydride, the peak at m/z =319.073 is the sodium ion mass spectrum addition peak of the reaction raw material methyl oleate, and the peak at m/z =449.288 is the sodium ion mass spectrum addition peak (trace) of the mono-esterified product formed by methanol as a solvent and the product ester succinic anhydride in the test process.

The key step of the present invention for preparing alkenyl succinimide or/and alkenyl succinamide is the preparation of alkenyl succinic anhydride, and as can be seen from fig. 1, preparation example 1 gives an oleic acid methyl ester based succinic anhydride compound.

Detailed Description

The following examples further illustrate the invention.

In the present invention, since biodiesel is generally mixed fatty acid methyl ester mainly containing octadecanoic acid, the molecular weight of biodiesel can be regarded as the same as that of methyl oleate (molecular weight 296) for the purpose of calculating the charge ratio.

Preparation examples 1 to 3 are intended to illustrate the synthesis of an alkenyl succinic anhydride.

Preparation example 1

242g of methyl oleate (98%, 0.8 mol) and 98g of maleic anhydride (1.0 mol) are added into a 500ml reactor provided with an electric stirrer, a thermometer, a reflux cold energy tube and a nitrogen inlet tube, nitrogen is introduced for 5-10 minutes, nitrogen protection is kept during the reaction process, the temperature is raised to 210 ℃ by heating and stirring, reflux reaction is carried out for 7 hours, excessive maleic anhydride is removed by reduced pressure distillation, the reaction intermediate alkenyl ester succinic anhydride containing the examples of the structural formula b8 and (or) structural formula b9 is obtained, and the content is about 66% as shown by mass spectrometry.

Preparation example 2

240g of biodiesel produced from waste cooking oil (produced by Ningbo Jisen Bio-energy Co., ltd., zhejiang province, wherein the fatty acid components are methyl palmitate 19.2%, methyl palmitoleate 0.9%, methyl stearate 6.7%, methyl oleate 43.9%, methyl linoleate 23.8%, methyl linolenate 2.9%) and 98.0g of maleic anhydride (1.0 mol) were charged into a 500ml reactor equipped with an electric stirrer, a thermometer, a reflux condenser and a nitrogen inlet tube, nitrogen was introduced for 5 to 10 minutes, the reaction was heated and stirred to 200 ℃ under nitrogen protection, the reaction was refluxed for 9 hours, and excess maleic anhydride was removed by reduced pressure distillation to obtain a reaction intermediate alkenylsuccinylsuccinic anhydride, and mass spectrometry showed that the content of alkenylsuccinylsuccinic anhydride was about 48.6%.

Preparation example 3

240g of biodiesel produced from distilled and low-temperature-frozen waste cooking oil (produced by Zhejiang Ningbo Jersen bioenergy Co., ltd., wherein the fatty acid components are methyl palmitate 0.5%, methyl palmitoleate 1.2%, methyl stearate 1.3%, methyl oleate 60.5%, methyl linoleate 29.2%, methyl linolenate 3.9%) and 98.0g of maleic anhydride (1.0 mol) are added into a 500ml reactor equipped with an electric stirrer, a thermometer, a reflux cold energy tube and a nitrogen gas inlet tube, nitrogen gas is introduced for 5-10 minutes while maintaining nitrogen protection in the reaction process, the temperature is raised to 200 ℃ by heating and stirring, reflux reaction is carried out for 9 hours, and excess maleic anhydride is removed by reduced pressure distillation, thus obtaining the reaction intermediate alkenyl succinic anhydride. Mass spectroscopy showed an alkenyl succinic anhydride content of about 56.3%.

Preparation examples 4 to 8 are provided to illustrate the synthesis of alkenyl succinimides or amides represented by structural formula b1 or b 2.

Preparation example 4

100g of the product of production example 1, 64g of tetraethylenepentamine (having an alkenyl succinic anhydride to polyamine molar ratio of about 1, 2) and 130g of toluene were charged into a 250ml three-necked flask, and the mixture was heated, stirred, refluxed, dehydrated and reacted for 6 hours, and the toluene was distilled off under reduced pressure to obtain 158g of an amination product mainly comprising an alkenyl succinamide.

Preparation example 5

100g of the product of production example 1, 25g of triethylene tetramine (the molar ratio of alkenyl succinic anhydride to polyamine is about 1).

Preparation example 6

100g of the product of preparation example 2 and 48g of tetraethylenepentamine were charged into a 250ml three-necked flask, and the mixture was heated and stirred at 95 ℃ to effect a reaction for dehydration for 8 hours, whereby 144g of an amination reaction product mainly comprising alkenylsuccinamide was obtained.

Preparation example 7

100g of the product of preparation example 3 and 48g of tetraethylenepentamine were charged into a 250ml three-necked flask, and the mixture was heated and stirred at 95 ℃ to effect a reaction for dehydration for 8 hours, thereby obtaining 145g of an amination reaction product mainly comprising alkenylsuccinamide.

Preparation example 8

100g of the product of preparation example 3 and 25g of N- (2-aminoethyl) piperazine were charged in a 250ml three-necked flask, and the mixture was heated at 150 ℃ with stirring to effect a reaction for 10 hours with water being distributed, whereby 114g of an amination reaction product mainly comprising an alkenylester succinimide was obtained.

Examples

Examples 1 to 6 are intended to illustrate the preparation of antioxidant compositions according to the invention. Component a and component b were mixed in the weight ratio shown in table 1.

TABLE 1

In table 1, the chemical name of the antioxidant 2246 is 2,2' -methylene-bis- (4-methyl-6-tert-butylphenol); the chemical name of the antioxidant T511 is 4,4' -methylene-bis- (2, 6-di-tert-butylphenol).

Comparative example 1

According to the method disclosed in CN101993743A, dodecenyl succinimide is prepared by firstly reacting dodecenyl succinic anhydride and tetraethylenepentamine according to the molar ratio of 1.

Comparative example 2

The dodecenyl succinimide prepared in the comparative example 1 is compounded with an antioxidant 2246 for use, wherein the compounding weight ratio is 1.

Comparative example 3

A monophenol antioxidant T501 (chemical name is 2, 6-di-tert-butyl-4-methylphenol) is compounded with preparation example 8 in a weight ratio of 2.

Example 7 Oxidation resistance test

In the following tests, biodiesel produced from palmitic acid oil was provided by Fujianlong New energy Co., ltd, and biodiesel produced from waste cooking oil was produced by NingboJensen bioenergy Co., ltd, zhejiang.

The oxidation stability of the biodiesel is evaluated by measuring the induction period at 110 ℃ by using an EN 14112 method (Racimat method), and the used instrument is a 743 grease oxidation stability tester of Switzerland company, wherein the longer the induction period is, the better the oxidation stability of the biodiesel is, and the shorter the induction period is, the worse the oxidation stability of the biodiesel is. The oxidation stability induction period of the biodiesel specified by national standards of China is not less than 6h. The results of the tests on biodiesel produced from palmitic acid oil are shown in table 2 and those from waste cooking oil are shown in table 3.

TABLE 2

As can be seen from the data in Table 2, component a is a bisphenol antioxidant, which has a certain improvement on the oxidation stability of biodiesel, and component b has a certain antioxidant effect when used alone, but after the component a and the component b are combined, the oxidation stability of biodiesel is much better than the sum of the effects of the component a and the component b when used alone, so that the obvious synergistic effect between the components a and b is surprisingly shown.

As can be seen from example 1, when antioxidant 2246 is added in 450mg/kg and 600mg/kg, the oxidation stability of the palmitic acid oil biodiesel is improved to 5.9hr and 7.6hr respectively, and when the addition amount of alkenyl succinamide corresponding to component b of the present invention in preparation example 4 is 150mg/kg and 600mg/kg, the oxidation stability of the palmitic acid oil biodiesel is improved to 4.7hr and 6.1hr respectively, and when the addition amount of the two is 600mg/kg (namely, 450mg/kg of antioxidant 2246 and 150mg/kg of alkenyl succinamide) after compounding in a weight ratio of 3. The two additives have synergistic effect after being used in a composite way, and the effect is greatly enhanced compared with that when the two additives are used alone. Other examples also show that the compositions of the present invention have significant synergistic results.

As shown in example 3, when the antioxidant 2246 and the alkenyl succinimide are compounded according to the weight ratio of 1. In comparative example 1, according to the method disclosed in CN101993743A, antioxidant 2246 and alkenyl succinimide are compounded according to the weight ratio of 1.

Comparative example 2, in which a monophenol-type antiwear agent T501 was compounded with component b of the present invention, it can be seen that the two did not exhibit significant synergy.

TABLE 3

As can be seen from the data in Table 3, after the component a and the component b are combined, the biodiesel produced from the waste cooking oil has a very obvious synergistic effect on improving the oxidation stability, and the addition amount is slightly larger because the oxidation stability of the biodiesel produced from the waste cooking oil is lower than that of the biodiesel produced from the palmitic acid oil.

As can be seen from the effect of example 1 in biodiesel produced from waste cooking oil, the antioxidant 2246 added at 800mg/kg increases the oxidation stability of biodiesel to 6.1hr, and the alkenyl succinamide of component b of the invention corresponding to preparation example 4 added at 800mg/kg increases the oxidation stability of biodiesel to 8.0hr, and the combination of these two compounds at the same dosage increases the oxidation stability of biodiesel to 12.8hr. The two additives have synergistic effect after being compounded and used, and the effect is greatly enhanced compared with that when the two additives are singly used. Other examples also show that the compositions of the present invention have significant synergistic results.

As can be seen from example 3, the antioxidant 2246 and alkenyl succinimide are compounded according to the weight ratio of 1. In comparative example 2, according to the method disclosed in CN101993743A, antioxidant 2246 and alkenyl succinimide are compounded according to the weight ratio of 1. The antioxidant composition disclosed by the invention has more excellent antioxidant effect than the antioxidant composition disclosed in CN 101993743A.

Comparative example 3, in which a monophenol-type antiwear agent T501 was compounded with the component b of the present invention, it can be seen that the two did not exhibit a significant synergistic effect.

Example 8 solubility test

The solubility test of the additive according to the invention in biodiesel was carried out with biodiesel produced from waste oil for meals, at an addition of 1500mg/kg, and the results are shown in Table 4, measured by visual inspection and Shimadzu UV-2600 UV spectrophotometer.

TABLE 4

As can be seen from Table 4, the additive of the present invention has good solubility in biodiesel, which is better than that of the product prepared by reacting alkenyl succinic anhydride in a comparative example.

Claims

1. The antioxidant composition for the biodiesel comprises a component a and a component b, wherein the component a is a bisphenol antioxidant formed by connecting two monophenols and/or a polyphenol antioxidant containing at least two phenolic hydroxyl groups on the same benzene ring; the component b is alkenyl ester-based succinimide shown in a structural formula b1 or/and alkenyl ester-based succinamide shown in a structural formula b 2:

wherein R is ₁ 、R ₂ Is alkyl, alkenyl, hydroxyalkyl, hydroxyalkenyl, R ₁ And R ₂ The total carbon number of (2) is 8-24, the total double bond number is 1 or 2 ₃ Is C1-C4 alkyl, R ₄ Is a C2-C30 group containing at least one nitrogen atom.

2. The antioxidant composition as claimed in claim 1, wherein R is ₁ And R ₂ Total carbon number of 16 to 20 ₃ Is methyl or ethyl, R ₄ Is a C2-C20 group containing at least one nitrogen atom.

3. The antioxidant composition as claimed in claim 1, wherein the mass ratio of the component a to the component b is 1.

4. The antioxidant composition as claimed in claim 1, wherein the mass ratio of the component a to the component b is 1.

5. The antioxidant composition as claimed in claim 1, wherein the bisphenol type antioxidant is a bisphenol antioxidant in which two monophenols having at least one t-butyl group ortho to the phenolic hydroxyl group are linked through a methylene group.

6. The antioxidant composition as claimed in claim 5, wherein the bisphenol-type antioxidant is selected from the group consisting of 2,2' -methylene-bis- (4-methyl-6-t-butylphenol), 4' -methylene-bis- (2, 6-di-t-butylphenol), 4' -methylene-bis- (2-t-butylphenol).

7. The antioxidant composition according to claim 1, wherein the polyphenol antioxidant is selected from the group consisting of t-butylhydroquinone and C1-C18 gallic acid esters.

8. A method of preparing the biodiesel antioxidant composition of claim 1, comprising: mixing the component a and the component b, wherein the preparation method of the component b comprises the following steps:

1) Performing addition reaction on a raw material containing C8-C24 unsaturated fatty acid alkyl ester and maleic anhydride to obtain alkenyl succinic anhydride;

2) And carrying out amination reaction on the alkenyl succinic anhydride and a polyamine compound to obtain alkenyl succinimide or/and alkenyl succinamide.

9. The preparation method according to claim 8, wherein in the step 1), the reaction molar ratio of the C8-C24 unsaturated fatty acid alkyl ester to the maleic anhydride is between 1; in the step 2), the molar ratio of the alkenyl succinic anhydride to the polyamine compound is 1.

10. The process according to claim 8, wherein, in the step 1), the reaction temperature is 150 to 280 ℃; in step 2), the amination reaction is carried out at a temperature of 40 to 280 ℃.

11. The process according to claim 8, wherein, in the step 1), the reaction temperature is 180 to 240 ℃; in the step 2), the amination reaction temperature is 60-180 ℃.

12. The preparation method according to claim 8, wherein in the step 1), the reaction molar ratio of the C8-C24 unsaturated fatty acid alkyl ester to the maleic anhydride is between 1; in the step 2), the molar ratio of the alkenyl succinic anhydride to the polyamine compound is 1.

13. The process according to claim 8, wherein the raw material containing C8-C24 unsaturated fatty acid alkyl ester is a C8-C24 long-chain olefinic acid containing one or two double bonds and optionally containing hydroxyl group, and the alkyl ester is C1-C4 alkyl ester.

14. The method according to claim 8, wherein the unsaturated fatty acid alkyl ester is selected from the group consisting of C12-C22 unsaturated fatty acid methyl ester and ethyl ester.

15. The method according to claim 8, wherein the unsaturated fatty acid alkyl ester is methyl oleate, methyl linoleate, methyl ricinoleate, or a mixture thereof.

16. The method according to claim 8, wherein the raw material containing C8-C24 unsaturated fatty acid alkyl ester is biodiesel having an unsaturated fatty acid methyl ester content of more than 60%.

17. The process according to claim 8, wherein the polyamine compound is a hydrocarbyl amine having two or more nitrogen atoms in the molecule, at least one hydrogen atom being bonded to a nitrogen atom.

18. The process according to claim 8, wherein the polyamine is a hydrocarbyl diamine, a polyene polyamine, an amine containing a nitrogen heterocyclic ring, and a condensate of a polyene polyamine with ethylene oxide or propylene oxide.

19. A biodiesel composition comprising biodiesel and the antioxidant composition of any of claims 1 to 7, wherein the antioxidant composition has a mass of 50 to 5000mg/kg relative to the mass of the biodiesel.

20. A diesel oil composition comprising biodiesel oil, petroleum diesel oil and the antioxidant composition according to any one of claims 1 to 7, wherein the antioxidant composition has a mass of 50 to 5000mg/kg relative to the mass of the biodiesel oil.

21. A diesel fuel composition according to claim 20, wherein the mass ratio of biodiesel to petrochemical diesel is 1.