CN109810744B - A kind of method for preparing biological lubricating oil catalyzed by acidic polymeric ionic liquid - Google Patents

Abstract

The application discloses a method for preparing biological lubricating oil catalyzed by an acidic polymeric ionic liquid, and belongs to the field of biological lubricating oil preparation. In the present invention, the acidic polymeric ionic liquid is used as a catalyst for the reaction, and the reaction of the epoxy methyl ester and the short-chain alcohol is catalyzed at 60-80° C. for 10-20 hours to obtain a reaction solution, which is cooled to room temperature, and subjected to gravity sedimentation. The polymerized ionic liquid is layered, and the present invention uses ionic liquid polymers with different carbon chain lengths to catalyze the ring-opening of epoxy methyl esters to prepare biological lubricating oils. The reaction raw materials are extensive, the reaction conditions are relatively mild, the operation is simple, the acidity can be recycled and the catalyst activity is high, and the synthesis is convenient.

Description

A kind of method for preparing biological lubricating oil catalyzed by acidic polymeric ionic liquid

technical field

The invention relates to a method for catalyzing an epoxy ring-opening isomerization reaction by an acidic polymeric ionic liquid, in particular to a method for preparing a biological lubricating oil catalyzed by an acidic polymeric ionic liquid.

Background technique

Biodiesel is mainly composed of mixtures of fatty acid methyl esters (FAMEs). Through epoxidation, the molecular structure of fatty acid methyl esters will have chemically unstable epoxy bonds. Oxygen bonds can react with a variety of substances, such as hydrolysis under acidic conditions, and polymerization with metal oxides to cause explosions. Therefore, it is necessary to chemically modify epoxy biodiesel. The addition reaction of ring-opening epoxy bond is a reasonable route for biodiesel to prepare biolubricating oil. Synthesis of lubricating oil base oil by chemical modification of biodiesel can increase the added value of biodiesel and improve its market competitiveness. At present, the most research is to use organic alcohols to combine with epoxy groups.

In the reaction of epoxy fatty acid methyl ester ring-opening to generate biological lubricating oil, the catalyst plays an important role, which affects the conversion rate of epoxy fatty acid methyl ester and the yield of biological lubricating oil. In addition, the recycling of catalysts is also a problem that must be considered in industrial production. Randomly discarding catalysts will cause great damage to the ecological environment. As far as the current form of catalyst development is concerned, green catalysts have gradually attracted people's attention. These green catalysts include: nanoparticle catalysts, ionic liquid catalysts, interlayer catalysts, enzyme or imitated enzyme catalysts, phase transfer catalysts, etc. Among them, ionic liquid catalysts have been paid more and more attention by researchers due to their advantages of easy chemical stability and good thermal stability. It is the key direction of future catalyst research to study the polymerization of ionic liquid to maintain its high catalytic activity and facilitate recycling.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a method for catalyzing the preparation of biological lubricating oil by an acidic polymeric ionic liquid, so as to overcome the defects existing in the known technology.

In order to achieve the above object, the method for preparing biological lubricating oil catalyzed by the acidic polymeric ionic liquid provided by the invention, the steps are:

A) The acidic polymeric ionic liquid is used as a catalyst for the reaction to catalyze the reaction of epoxy methyl ester and organic alcohol at 60-80° C. for 10-20 hours;

The polymerized monomer of the acidic polymerized ionic liquid can be selected from vinyl, allyl or allyl imidazolium ionic liquid.

The structural formula of the acidic ionic liquid monomer is

Wherein, R is -CH=CH ₂ , -CH ₂ -CH=CH ₂ or -CH ₂ -CH ₂ -CH=CH ₂

Described reactant is epoxy methyl ester and organic alcohol, and wherein epoxy methyl ester and organic alcohol mol ratio are 1:1 to 1:6;

The mass ratio of the acidic polymeric ionic liquid to the epoxy methyl ester is 1:4 to 1:60.

B) The reaction solution obtained in step A is cooled to room temperature, and gravity settled, the product is layered with the acidic polymeric ionic liquid, and the upper layer liquid is decompressed to remove unreacted organic alcohol to obtain the product.

Wherein, the acidic polymeric ionic liquid separated in step B is repeatedly used for the reaction.

Wherein, in step A, the raw material is obtained by transesterification and epoxidation of vegetable oil to obtain epoxy methyl ester; the alcohols are methanol, ethanol, propanol, isopropanol, n-butanol, isobutanol, amyl alcohol, and octanol. one or more.

Compared with the background technology, the technical progress achieved by the present invention is:

The invention innovatively proposes to use B acid ionic liquid polymers with different carbon chain lengths to catalyze the ring-opening of epoxy methyl esters to prepare biological lubricants. This type of ionic liquid is polymerized by acid groups with adjustable carbon chain length, and the degree of polymerization is controllable and adjustable, and the catalytic reaction in the heterogeneous system can be efficiently realized in the reactor; therefore, its acidity and surface activity can be used to promote The ring-opening reaction proceeds continuously. The catalyst of the invention can be used as a catalyst for the synthesis of biological lubricating oil to carry out the epoxy ring-opening isomerization etherification reaction process. The acid ionic liquid polymer has great application potential in the field of biological lubricating oil production. Lay the foundation for domestic promotion. Its specific advantages are as follows:

1. Wide range of reaction raw materials, such as vegetable oil, waste food waste oil and other derivative products of epoxy fatty acid methyl ester.

2. The reaction conditions are relatively mild and the operation is simple.

3. The reaction product phase and the catalyst phase are immiscible and automatically stratified, and are easy to separate.

4. The catalyst is an acidic polymeric ionic liquid with controllable and adjustable structure, stable performance, no acid loss, recyclable use and high catalyst activity; convenient synthesis and good atomic economy.

5. Overcoming the problems of difficult liquid separation and weak catalytic activity of common catalysts in the background art.

6. There is no waste water discharge in the preparation process, and excess reactants can be recycled for multiple times, which is an environmentally friendly process route.

Detailed ways

The method for preparing biological lubricating oil catalyzed by the acidic polymeric ionic liquid provided by the invention is that the acidic polymeric ionic liquid is used to catalyze the ring-opening isomerization reaction of epoxy methyl ester, and an environment-friendly process route is provided for the preparation of biological lubricating oil. .

The acidic polymeric ionic liquid used in the present invention is a sulfonic acid group-functionalized alkyl polyvinylimidazole sulfonic acid, and its synthesis process is as follows, wherein the polymerization monomers can be selected from vinyl, allyl, and allyl imidazole ionic liquids . The degree of polymerization is controllable and adjustable.

The specific synthesis steps of the acid polymerization vinyl ionic liquid catalyst are:

The acidic polymerized vinyl ionic liquid used in the present invention can be prepared by the following methods:

At 0 °C, slowly add 1-vinylimidazole and butane sultone to the flask, stir at room temperature for 24 h, and finally wash the product with diethyl ether, and vacuum dry (25 °C, 6 h) to obtain 1-vinylimidazobutine Alkane sulfonic acid. At 0 °C, slowly add equimolar trifluoromethanesulfonic acid and 1-vinylimidazobutanesulfonic acid to the round-bottomed flask, and react at 60 °C for 12 h to obtain [VIm(CH ₂ ) ₄ SO ₃ H] [CF ₃ SO ₃ ]. The reaction product was washed with ether and dried in vacuo (50°C, 2h). A certain amount of [VIm(CH ₂ ) ₄ SO ₃ H][CF ₃ SO ₃ ] was added to N,N-dimethylformamide (DMF), and after it was completely dissolved by stirring, a certain amount of initiator was added Azobisisobutyronitrile (AIBN) was heated to 60°C under nitrogen protection, and the reaction was continuously stirred for 24h. After the reaction is completed, ethyl acetate is added to the reaction solution to promote the precipitation of the product to obtain an acidic polymerization vinyl ionic liquid catalyst.

The preparation method and conditions of the acid polymerized allyl ionic liquid or the acid polymerized allyl ionic liquid catalyst are the same as above, except that 1-vinylimidazole is replaced with 1-allylimidazole or 1-butenylimidazole After the reaction, an acidic polymeric allyl ionic liquid or an acidic polymeric allyl ionic liquid catalyst is obtained, respectively.

The structural formula of the acidic polymeric allyl ionic liquid catalyst is as follows:

The structural formula of the acidic polymerized alkenyl ionic liquid catalyst is as follows:

In the present invention, after the prepared catalyst catalyzes the ring-opening reaction of epoxy fatty acid methyl ester and organic alcohol, gravity settles, the product and the catalyst are layered, and the reaction product liquid is decompressed to remove volatile matter, so as to prepare biological lubricating oil, and acid polymerization The ionic liquid catalyst can be reused after recovery.

Adopt the above-mentioned catalyst to catalyze the epoxy bond ring-opening in the epoxy fatty acid methyl ester to carry out the addition reaction to synthesize the biological lubricating oil step as follows:

Preparation of biological lubricating oil: In a three-necked flask equipped with a magnetic stirrer or mechanical stirring, a reflux condenser and a thermometer, add a certain proportion of epoxy methyl ester, organic alcohol, and the above-mentioned acidic polymerized ionic liquid catalyst, among which epoxy methyl ester The molar ratio of ester to organic alcohol is 1:1 to 1:6, and the mass ratio of acidic polymeric ionic liquid to epoxy methyl ester is 1:4 to 1:60. The temperature is raised to the reaction temperature to start the reaction timing. After the predetermined reaction time, the reaction is stopped. After the reaction solution is cooled and allowed to stand, the product is layered with the acidic polymer ionic liquid. The polymer ionic liquid separated from the lower layer can be reused after simple treatment. The upper layer is reacted The organic alcohol is removed by distillation of the product liquid to obtain a biological lubricating oil product.

The mechanism of preparing bio-lubricating oil is as follows:

The method of the present invention will be further described below in conjunction with the examples, which are not limitations of the present invention.

Example 1:

Weigh 68g of ethanol and 4g of acid vinyl ionic liquid monomer catalyst and place it in a four-necked flask with a condenser tube and a thermometer, heat to 80°C under stirring, then add 200g of epoxidized soybean oil fatty acid methyl ester, and measure The initial epoxy value of the reaction system was 5.46, and the ring-opening reaction was carried out at this temperature. During the reaction, samples were taken every 30 minutes to measure the epoxy value. The reaction time was t=12h, and the reaction was stopped. The above solution was cooled to room temperature, allowed to settle, and centrifuged to separate the acid vinyl ionic liquid monomer. It was found that the ionic liquid monomer catalyst was difficult to separate, and it was difficult to recover and recycle. The reaction solution was decompressed and distilled to finally obtain clear and transparent ethanol. Modified biological lubricants. The epoxy value of the bio-lubricating oil was 1.076, the conversion rate was 80.3%, the acid value was 1.73 (mgKOH/g), and the kinematic viscosity at 40°C was 38.49 (mm ² /s).

Example 2:

Weigh 68g of ethanol and 4g of acidic polymerization vinyl ionic liquid catalyst and place it in a four-necked flask with a condenser tube and a thermometer, heat to 80°C under stirring, then add 200g of epoxidized soybean oil fatty acid methyl ester, and measure the reaction The initial epoxy value of the system was 5.46, and the ring-opening reaction was carried out at this temperature. During the reaction, samples were taken every 30 minutes to measure the epoxy value. When the epoxy value was less than 0.08 (t=10h), the reaction was stopped. The above solution is cooled to room temperature, allowed to settle, the product is layered with the acidic polymeric ionic liquid, the lower layer is centrifuged to obtain an acidic polymeric ionic liquid catalyst, and the upper layer reaction solution is decompressed and distilled to finally obtain a clear and transparent ethanol-modified biological lubricating oil. The epoxy value of the bio-lubricating oil was 0.172, the conversion rate was 96.8%, the acid value was 0.95 (mgKOH/g), and the kinematic viscosity at 40°C was 38.51 (mm ² /s).

Example 3:

Weigh 68g of ethanol and 4g of acidic polymerization vinyl ionic liquid catalyst and place it in a four-necked flask with a condenser tube and a thermometer, heat to 80°C under stirring, then add 200g of epoxidized soybean oil fatty acid methyl ester, and measure the reaction The initial epoxy value of the system was 5.46, and the ring-opening reaction was carried out at this temperature. During the reaction, samples were taken every 30 minutes to measure the epoxy value. When the epoxy value was less than 0.08 (t=12h), the reaction was stopped. The above solution is cooled to room temperature, allowed to settle, the product is layered with the acidic polymeric ionic liquid, the lower layer is centrifuged to obtain an acidic polymeric ionic liquid catalyst, and the upper layer reaction solution is decompressed and distilled to finally obtain a clear and transparent ethanol-modified biological lubricating oil. The epoxy value of the bio-lubricating oil was 0.069, the conversion rate was 98.7%, the acid value was 0.78 (mgKOH/g), and the kinematic viscosity at 40°C was 38.53 (mm ² /s).

Example 4:

Weigh 84.4g of isopropanol and 4g of acid polymerization vinyl ionic liquid catalyst and place in a four-necked flask with a condenser tube and a thermometer, heat to 70°C under stirring, then add 200g of epoxy rapeseed oil fatty acid methyl ester, The initial epoxy value of the reaction system was measured to be 5.46, and the ring-opening reaction was carried out at this temperature. During the reaction, samples were taken every 30 minutes to measure the epoxy value. When the epoxy value was less than 0.08 (t=14h), the reaction was stopped. The above solution is cooled to room temperature, allowed to settle, the product is layered with the acidic polymeric ionic liquid, the lower layer is centrifuged to obtain an acidic polymeric ionic liquid catalyst, and the upper layer reaction solution is decompressed and distilled to finally obtain a clear and transparent isopropanol-modified organism. lubricating oil. The epoxy value of the bio-lubricating oil was 0.068, the conversion rate was 98.8%, the acid value was 0.79 (mgKOH/g), and the kinematic viscosity at 40°C was 37.54 (mm ² /s).

Example 5:

Weigh 114.4g of n-butanol and 4g of acidic polymerization vinyl ionic liquid catalyst and place them in a four-necked flask with a condenser tube and a thermometer, heat to 70°C under stirring, then add 200g of epoxy castor oil fatty acid methyl ester, measure The initial epoxy value of the reaction system was 5.46, and the ring-opening reaction was carried out at this temperature. During the reaction, samples were taken every 30 minutes to measure the epoxy value. When the epoxy value was less than 0.08 (t=10h), the reaction was stopped. The above solution is cooled to room temperature, the above solution is cooled to room temperature, the above solution is cooled to room temperature, allowed to settle, the product is layered with the acidic polymeric ionic liquid, the lower layer is centrifuged to obtain an acidic polymeric ionic liquid catalyst, and the upper layer reaction solution is distilled under reduced pressure, Finally, a clear and transparent n-butanol-modified biological lubricant was obtained. The epoxy value of the bio-lubricating oil was 0.075, the conversion rate was 98.6%, the acid value was 0.72 (mgKOH/g), and the kinematic viscosity at 40°C was 34.48 (mm ² /s).

Example 6:

Weigh 114.4g of isobutanol and 4g of acidic polymerization vinyl ionic liquid catalyst and place them in a four-necked flask with a condenser tube and a thermometer, heat to 70°C under stirring, then add 200g of epoxy castor oil fatty acid methyl ester, measure The initial epoxy value of the reaction system was 5.46, and the ring-opening reaction was carried out at this temperature. During the reaction, samples were taken every 30 minutes to measure the epoxy value. When the epoxy value was less than 0.08 (t=10h), the reaction was stopped. The above solution is cooled to room temperature, the above solution is cooled to room temperature, the above solution is cooled to room temperature, allowed to settle, the product is layered with the acidic polymeric ionic liquid, the lower layer is centrifuged to obtain an acidic polymeric ionic liquid catalyst, and the upper layer reaction solution is distilled under reduced pressure, Finally, a clear and transparent isobutanol-modified biological lubricating oil was obtained. The epoxy value of the bio-lubricating oil was 0.066, the conversion rate was 98.8%, the acid value was 0.79 (mgKOH/g), and the kinematic viscosity at 40°C was 35.50 (mm ² /s).

Example 7:

Weigh 68g of ethanol and 4g of acidic polymerized allyl ionic liquid catalyst and place it in a four-necked flask with a condenser tube and a thermometer, heat to 80°C under stirring, then add 200g of epoxidized soybean oil fatty acid methyl ester, and measure The initial epoxy value of the reaction system was 5.46, and the ring-opening reaction was carried out at this temperature. During the reaction, samples were taken every 30 minutes to measure the epoxy value. When the epoxy value was less than 0.08 (t=10h), the reaction was stopped. The above solution is cooled to room temperature, allowed to settle, the product is layered with the acidic polymeric ionic liquid, the lower layer is centrifuged to obtain an acidic polymeric ionic liquid catalyst, and the upper layer reaction solution is decompressed and distilled to finally obtain a clear and transparent ethanol-modified biological lubricating oil. The epoxy value of the bio-lubricating oil was 0.07, the conversion rate was 98.7%, the acid value was 0.76 (mgKOH/g), and the kinematic viscosity at 40°C was 38.32 (mm ² /s).

Example 8:

Weigh 68g of ethanol and 4g of acidic polymerized alkenyl ionic liquid catalyst and place them in a four-necked flask with a condenser tube and a thermometer, heat to 80°C under stirring, then add 200g of epoxidized soybean oil fatty acid methyl ester, and measure The initial epoxy value of the reaction system was 5.46, and the ring-opening reaction was carried out at this temperature. During the reaction, samples were taken every 30 minutes to measure the epoxy value. When the epoxy value was less than 0.08 (t=10h), the reaction was stopped. The above solution is cooled to room temperature, allowed to settle, the product is layered with the acidic polymeric ionic liquid, the lower layer is centrifuged to separate the acidic polymeric ionic liquid catalyst, and the upper layer of the reaction solution is decompressed and distilled to finally obtain a clear and transparent ethanol-modified biological lubricating oil. The epoxy value of the bio-lubricating oil was 0.069, the conversion rate was 98.7%, the acid value was 0.77 (mgKOH/g), and the kinematic viscosity at 40°C was 38.23 (mm ² /s).

Claims (3)

1. A method for preparing biological lubricating oil by acidic polymerization ionic liquid catalysis is characterized in that: the acidic polymeric ionic liquid is one of the following structural formulas:

；

；

；

the method for preparing the biological lubricating oil by the catalysis of the acidic polymeric ionic liquid comprises the following steps:

A. taking the acidic polymerized ionic liquid as a catalyst for reaction, catalyzing epoxy fatty acid methyl ester to react with short-chain alcohol at the temperature of 60-80 ℃ for 10-20 hours, and stopping the reaction when the epoxy value is less than 0.08 to obtain reaction liquid;

B. cooling the reaction liquid prepared in the step A to room temperature, standing and settling to enable the product to be layered with the acidic polymeric ionic liquid, separating the lower layer to obtain an acidic polymeric ionic liquid catalyst, and decompressing the upper layer liquid product to remove short-chain alcohol to obtain biological lubricating oil;

the epoxidized fatty acid methyl ester is epoxidized castor oil fatty acid methyl ester, epoxidized soybean oil fatty acid methyl ester or epoxidized rapeseed oil fatty acid methyl ester, and the short-chain alcohol is ethanol, propanol, isopropanol, n-butanol or isobutanol;

the preparation method of the acidic polymeric ionic liquid comprises the following steps: slowly adding 1-vinylimidazole and butane sultone into a flask at 0 ℃, stirring for 24 hours at room temperature, washing a product with diethyl ether, and performing vacuum drying for 6 hours at 25 ℃ to obtain 1-vinylimidazole butane sulfonic acid; slowly adding equimolar trifluoromethanesulfonic acid and 1-vinyl imidazole butane sulfonic acid into a round-bottom flask at 0 ℃, and reacting for 12h at 60 ℃ to obtain [ VIm (CH)₂)₄SO₃H] [CF₃SO₃]Washing the reaction product with ether, vacuum drying at 50 deg.C for 2 hr, and collecting certain amount of [ VIm (CH)₂)₄SO₃H] [CF₃SO₃]Adding N, N-dimethyl formamide (DMF), stirring to dissolve completely, adding a certain amount of initiator Azobisisobutyronitrile (AIBN), heating to 60 deg.C under nitrogen protection, stirring for 24 hr, and adding into the reaction solution after reactionAdding ethyl acetate to promote the product to be separated out, and obtaining the acidic polymerization vinyl ionic liquid catalyst;

and (2) replacing the 1-vinyl imidazole with 1-allyl imidazole or 1-butenyl imidazole, and reacting to obtain the acidic polymeric allyl ionic liquid or acidic polymeric alkenyl butyl ionic liquid catalyst respectively.

2. The method for preparing biological lubricating oil catalyzed by acidic polymeric ionic liquid according to claim 1, wherein: the molar ratio of the epoxy methyl ester to the short-chain alcohol is 1: 1-1: 4; the mass ratio of the acidic polymeric ionic liquid to the epoxy methyl ester is 1: 4-1: 60.

3. The method for preparing biological lubricating oil catalyzed by acidic polymeric ionic liquid according to claim 1, wherein: and the acidic polymeric ionic liquid separated in the step B is repeatedly used for reaction.