Process for synthesizing dibasic acid diester from dehydrated castor oil and allyl compound

Abstract

The invention belongs to the technical field of chemical engineering, and particularly discloses a process for synthesizing dibasic acid diester from dehydrated castor oil and an allyl compound. The method comprises the following steps: forming a high-pressure state in a high-pressure kettle by utilizing nitrogen, injecting an allyl compound into the high-pressure kettle filled with dehydrated castor oil at a constant speed by taking a small amount of iodine as a catalyst and adopting a high-pressure constant-flow pump, and synthesizing a dehydrated castor oil addition product by utilizing linoleic acid and oleic acid components in the dehydrated castor oil and the allyl compound; and directly carrying out ester exchange reaction on the addition product and proper unit fatty alcohol to obtain various dibasic acid diester base oils with six-membered ring structures. The process is short in reaction time, few in by-products, low in cost and high in biodegradation rate, and the product dibasic acid diester belongs to green plant-based ester base oil. The product obtained by the technical scheme has good pour point, viscosity and electrical property, and can be widely applied to the fields of hydraulic oil, metal working fluid, transformer oil and the like.

Description

Technical Field

[0001] The invention relates to the technical field of chemical industry, and in particular to a process for synthesizing a dibasic acid diester from dehydrated castor oil and an allyl compound. Background Art

[0002] As people's awareness of environmental crises grows, they generally realize that the environmental pollution problems caused by the large amount of existing mineral-based lubricants during production, use and discharge due to penetration, leakage, overflow and improper handling are becoming more and more serious. From the trend of social development, environmentally friendly lubricants will gradually replace the existing mineral-based lubricants.

[0003] Environmentally friendly lubricants are mainly bio-based lubricants, which are modified from dehydrated castor oil or lubricants that can be decomposed into water and carbon dioxide by active microorganisms in a relatively short period of time. They have the following characteristics: they have good lubrication properties and can reduce environmental pollution by saving energy; the product itself is non-toxic to the environment and has little impact; the product can be biodegraded and can be decomposed into simple CO2 and water and absorbed by the environment without harm.

[0004] Environmentally friendly lubricants are mainly based on vegetable oils. Compared with traditional mineral lubricants, the natural renewable and biodegradable properties of vegetable oils can provide obvious environmental and economic sustainable development benefits. In addition, vegetable oils also have the advantages of low volatility, high flash point, high viscosity index and excellent lubricity. Therefore, bio-based lubricants with vegetable oil as the main source have become the main force of environmentally friendly lubricants.

[0005] Vegetable oil contains 30-70% linoleic acid, which can be converted into linoleic acid by iodine catalysis, and can undergo Diels-Alder addition reaction with some monoolefin compounds to form compounds with six-membered ring structure. For example, linoleic acid can undergo addition reaction with acrylic acid, fumaric acid, etc. under iodine catalysis to form dibasic acid and tribasic acid structure adducts with six-membered ring. Domestic and foreign related literature and patents generally use fatty acids (containing linoleic acid) and acrylic acid under iodine catalysis, under normal pressure for addition reaction, and then esterify the obtained dibasic acid and alcohols to form dibasic acid esters. This esterification reaction requires a long reaction time and requires a large amount of water for washing, etc., and the process is complicated and increases the cost.

[0006] However, the existing process can only ensure the smooth conjugation and addition reaction when a large amount of iodine and a high temperature are used. On the one hand, such a process is prone to self-polymerization of vegetable oil acid, acrylic acid, etc., and also brings a darker color, resulting in a poor appearance of the product, affecting the quality and application of the product. On the other hand, due to the normal pressure, the mass transfer between the low-boiling point acrylic acid and the easily sublimated iodine and the material is insufficient, the reaction rate is reduced, the energy consumption is increased, and the production efficiency is low. Summary of the invention

[0007] The purpose of the present invention is to provide a process for synthesizing a dibasic acid diester from dehydrated castor oil and an allyl compound, so as to solve the problems that the dibasic acid diester prepared by the existing process using vegetable oil acid and acrylic acid has a long reaction time under normal pressure, complicated procedures, and insufficient reaction, resulting in high energy consumption and low production efficiency in the preparation process of the dibasic acid diester.

[0008] To achieve the above object, the basic scheme provided by the present invention is: a process for synthesizing a dibasic acid diester from dehydrated castor oil and an allyl compound, characterized in that it comprises the following steps:

[0009] S1: In an autoclave containing dehydrated castor oil, a certain amount of iodine is added into the autoclave and nitrogen is introduced, the temperature is raised to 180-240° C., a stirrer is turned on, and an allyl compound is uniformly injected into the autoclave using a high-pressure constant-current pump, and the reaction is continued for 1-3 hours, and the decompression is reduced to obtain a mixture of dehydrated castor oil adduct and allyl compound;

[0010] S2: performing a reduced pressure vacuum distillation operation on the mixture obtained in step S1 to remove the allyl compound that has not participated in the reaction, thereby obtaining a dehydrated castor oil adduct;

[0011] S3: adding the dehydrated castor oil adduct obtained in step S2 to a three-necked flask of a reflux condenser, and adding mono fatty alcohol to the three-necked flask, using sodium methoxide as an alkaline catalyst, the dehydrated castor oil adduct and the mono fatty alcohol undergo an ester exchange reaction under the catalysis of sodium methoxide, and recovering excess mono fatty alcohol under reduced pressure and vacuum, and then standing until stratification, separating glycerol, and obtaining a mixture of dibasic acid diesters and fatty acid esters;

[0012] S4: performing a distillation operation using a vacuum distillation apparatus, slowly injecting the mixture of the dibasic acid diester and the fatty acid ester produced in step S3 into the vacuum distillation apparatus, and separating the dibasic acid diester and the fatty acid ester by distillation to obtain a dibasic acid diester base oil.

[0013] The principle and beneficial effects of the present invention are as follows: the present invention utilizes nitrogen to form a high pressure state in an autoclave, uses a relatively small amount of iodine as a catalyst, and uses a high pressure constant flow pump to uniformly inject an allyl compound into an autoclave containing dehydrated castor oil, utilizes linoleic acid and oleic acid components present in the dehydrated castor oil, and synthesizes dehydrated castor oil adducts with the allyl compound, and the adducts directly undergo an ester exchange reaction with a suitable unit fatty alcohol to obtain a variety of dibasic acid diester base oils with a six-membered ring structure, the reaction time is short, the product has few by-products, the cost is low, the biodegradability is high, and it belongs to a green plant-based ester base oil. In the preparation process of the dibasic acid diester, the following beneficial effects are also produced:

[0014] First, the scheme utilizes the closed environment of the autoclave to realize the addition of dehydrated castor oil with an allyl compound under high-pressure nitrogen filling conditions. Under the protection of nitrogen, the self-polymerization of the dehydrated castor oil is effectively avoided, the utilization rate of the raw materials is improved, and the preparation of the dibasic acid diester is promoted.

[0015] Second, under the protection of nitrogen, the allyl compound is injected at a uniform speed using a high-pressure constant-flow pump, thereby avoiding the self-polymerization of the allyl compound and improving the utilization rate of the material.

[0016] Third, since the reaction is carried out at a pressure of not less than 1 MPa, the utilization rate of easily sublimated iodine is improved, the amount of iodine used is reduced, the color of the product is lightened, and the chromaticity of the product is reduced.

[0017] Fourth, under the condition of high-pressure nitrogen filling, it is conducive to the full contact of the allyl compound with a lower boiling point with the dehydrated castor oil, and the mass transfer rate of the easily sublimated iodine and the allyl compound with a lower boiling point in the material can be increased, thereby increasing the Diels-Alder addition reaction rate of the linoleic acid and oleic acid components in the dehydrated castor oil with the allyl compound, thereby reducing the reaction time.

[0018] The product prepared by the process of this scheme has low cost and high biodegradability, and belongs to green plant-based ester base oil. In addition, the kinematic viscosity of the product is tested to be between 30 and 60 mm 2 / s, pour point -40~-55℃, acid value less than 0.02mgKOH / g, dielectric loss less than 0.02, and breakdown voltage greater than 75Kv. Therefore, the product can be used in the field of metalworking fluids, can replace existing anti-wear hydraulic oils, and can also be used as plant-based transformer oil, with good effectiveness.

[0019] Scheme 2 is a preferred embodiment of the basic scheme. In steps S1 and S2, the allyl compound includes one of butyl acrylate, isobutyl acrylate, octyl acrylate, isooctyl acrylate, butyl methacrylate, isobutyl methacrylate, octyl methacrylate, and isooctyl methacrylate; methacrylate and acrylate are allyl compounds, and any of the above-mentioned methacrylates and acrylates can be used as a reaction raw material for reacting with dehydrated castor oil to prepare a dibasic acid diester.

[0020] Scheme 3 is a preferred embodiment of the basic scheme. In step S1, the dehydrated castor oil is industrial dehydrated castor oil. The use of industrial-grade dehydrated castor oil can control the cost of raw materials.

[0021] Scheme 4 is a preferred embodiment of Scheme 2. In step S1, the iodine added is 0.1-0.3%wt of the mass of dehydrated castor oil; iodine is used as a conjugation agent for dehydrated castor oil and allyl compounds, and iodine plays a certain role in promoting the reaction process when participating in the reaction; if it is less than 0.1%, it will affect the reaction process and cause the reaction to be insufficient; if the amount of iodine used exceeds 1% or even more, the product color will be darker, affecting the appearance of the obtained dibasic acid diester product.

[0022] Scheme 5 is a preferred embodiment of Scheme 2. In step S1, the pressure of the nitrogen filling is maintained at 1.0 MPa. Under the condition of not less than 1 MPa, the reaction between the dehydrated castor oil and the allyl compound can be promoted to occur and proceed faster.

[0023] Scheme 6 is a preferred basic scheme. In step S3, the unit fatty alcohol is one of butanol, isobutanol, octanol and isooctyl alcohol; fatty alcohol refers to an alcohol in which a hydroxyl group is connected to an aliphatic hydrocarbon group, and any unit fatty alcohol of butanol, isobutanol, octanol and isooctyl alcohol can undergo an ester exchange reaction with a monoester of a dibasic acid.

[0024] Scheme 7 is a preferred embodiment of Scheme 6. In step S3, the amount of the mono fatty alcohol substance added to the three-necked flask is 3 to 4 times the amount of the dehydrated castor oil adduct. Reasonable control of the ratio of the mono fatty alcohol and the dehydrated castor oil helps to make the transesterification reaction more complete.

[0025] Scheme 8 is a preferred basic scheme. In step S3, the amount of sodium methoxide used is 0.2 to 1.0% wt of the total material amount. Sodium methoxide is a catalyst commonly used in ester exchange reactions. Using sodium methoxide as a catalyst can effectively promote ester exchange reactions and improve reaction rate and yield.

[0026] Scheme 9 is a preferred embodiment of Scheme 7, wherein the vacuum degree during the reduced pressure distillation operation is 0.05 MPa to 0.099 MPa; in a vacuum environment, fatty acid esters and mono-fatty alcohols can be extracted from the product dibasic acid diester without heating the temperature to a very high level, thereby reducing the heating cost; when the temperature is lower than 0.05 MPa, it is close to room temperature and cannot play a role in lowering the reaction temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a reaction equation for preparing a dibasic acid diester from dehydrated castor oil and an allyl compound in a process for synthesizing a dibasic acid diester from dehydrated castor oil and an allyl compound of the present invention;

[0028] Figure 2 It is an infrared spectrum of a dibasic acid diester in a process for synthesizing a dibasic acid diester from dehydrated castor oil and an allyl compound of the present invention; DETAILED DESCRIPTION

[0029] The present invention is further described in detail below through specific embodiments:

[0030] like Figure 1 and Figure 2 As shown: A process for synthesizing a dibasic acid diester from dehydrated castor oil and an allyl compound comprises the following specific steps:

[0031] S1: 1000 g of dehydrated castor oil (1.07 mol) is placed in an autoclave, 0.1-0.3%wt of iodine based on the mass of the dehydrated castor oil is added into the autoclave, and nitrogen is introduced so that the reaction can be carried out under a closed condition. After the nitrogen is introduced, the pressure in the autoclave is maintained at at least 1.0 MPa, the temperature is raised to 180-240° C., an agitator is turned on, and an allyl compound is uniformly injected into the reactor using a high-pressure constant-current pump, wherein the allyl compound is any one of butyl acrylate, isobutyl acrylate, octyl acrylate, isooctyl acrylate, butyl methacrylate, isobutyl methacrylate, octyl methacrylate, and isooctyl methacrylate, and any of the allyl compounds can be used in place of each other, and each of the allyl compounds having the same performance can be used as a reaction raw material, and the reaction is continued for 1-3 hours, and the decompression is performed to obtain a mixture of dehydrated castor oil adduct and the allyl compound;

[0032] S2: performing a reduced pressure vacuum distillation operation on the mixture obtained in step S1 to remove the allyl compound that has not participated in the reaction, thereby obtaining a dehydrated castor oil adduct;

[0033] S3: adding the dehydrated castor oil adduct obtained in step S2 to a three-necked flask of a reflux condenser, and adding a mono fatty alcohol in an amount of 3 to 4 times the amount of the adduct to the three-necked flask, wherein the mono fatty alcohol is one of butanol, isobutanol, octanol and isooctyl alcohol; using sodium methoxide as an alkaline catalyst, the amount of sodium methoxide is 0.2 to 1.0%wt of the total material;

[0034] The dehydrated castor oil adduct and the mono fatty alcohol are subjected to an ester exchange reaction under the catalysis of sodium methoxide, and the excess mono fatty alcohol is recovered under reduced pressure and vacuum, and the vacuum degree during the reduced pressure distillation operation is 0.05MPa-0.099MPa; then the mixture is allowed to stand until stratification, and glycerol is separated to obtain a mixture of dibasic acid diesters and fatty acid esters;

[0035] S4: using a vacuum distillation apparatus to perform distillation operation, slowly injecting the mixture of the dibasic acid diester and the fatty acid ester produced in step S3 into the vacuum distillation apparatus, distilling and separating the dibasic acid diester and the fatty acid ester to obtain a dibasic acid diester base oil; the reaction equation for preparing the dibasic acid diester using dehydrated castor oil and an allyl compound is as follows: Figure 1 The infrared spectrum of the finally obtained dibasic acid diester base oil product is shown in Figure 2shown.

[0036] The technical solution of the present invention is described in more detail below through specific embodiments, but it is not intended to limit the protection scope of the present invention.

[0037] Embodiment 1

[0038] 1000 g of dehydrated castor oil (1.07 mol) and 1.0 g of iodine (mass fraction 0.1%) were added to the autoclave, nitrogen was filled into the autoclave, air was exhausted, the autoclave was heated to 220° C. in a sealed state, the pressure in the autoclave reached at least 1.0 MPa, 3.21 mol of butyl methacrylate (455.8 g) was uniformly injected into the autoclave by a high-pressure constant-current pump, the amount of butyl methacrylate being 3 times the amount of the dehydrated castor oil substance, and the pressure was kept constant for 1 hour thereafter. The autoclave was then cooled and decompressed to obtain a mixture of dehydrated castor oil adduct and butyl methacrylate.

[0039] The mixture of the dehydrated castor oil adduct and butyl methacrylate obtained above is subjected to reduced pressure vacuum distillation operation to recover the butyl methacrylate that has not participated in the reaction to obtain the dehydrated castor oil adduct.

[0040] 148 g of butanol (2 mol) was weighed and added to a three-necked flask of a reflux condenser, and 1.37 g of sodium methoxide (0.2% by weight) was added to the three-necked flask, the three-necked flask was heated, and then 537 g of dehydrated castor oil adduct (0.5 mol) was added to increase the reaction temperature of the dehydrated castor oil adduct and butanol, and the two were subjected to ester exchange reaction under mechanical stirring, and the reaction was terminated when no water was generated.

[0041] After the reaction is completed, the excess butanol is recovered under reduced pressure and vacuum, and the mixture is allowed to stand until layers are separated, and the glycerol in the lower layer is separated to obtain a mixture of dibasic acid diesters and fatty acid butyl esters; the dibasic acid diesters and fatty acid butyl esters are subjected to reduced pressure distillation at 210°C to distill out fatty acid butyl ester to obtain a dibasic acid diester product.

[0042] After measurement, the kinematic viscosity of the obtained dibasic acid diester base oil product is 42 mm 2 / s, pour point is -45℃, acid value is 0.02mgKOH / g, breakdown voltage is 78Kv, and dielectric loss is 0.02.

[0043] Embodiment 2

[0044] 1000 g of dehydrated castor oil (1.07 mol) and 1.5 g of iodine (mass fraction 0.15%) were added to an autoclave, nitrogen was introduced into the autoclave, air was exhausted, the autoclave was heated to 220° C. in a sealed state, the pressure in the autoclave reached at least 1.0 MPa, 438 g of 3.424 mol of butyl acrylate was uniformly injected into the autoclave using a high-pressure constant-current pump, the amount of butyl acrylate being 3.2 times the amount of the dehydrated castor oil substance, and the pressure was kept constant for the next 2 hours. The autoclave was then cooled and decompressed to obtain a mixture of dehydrated castor oil adduct and butyl acrylate.

[0045] The mixture of the dehydrated castor oil adduct obtained above and butyl acrylate is subjected to reduced pressure vacuum distillation to recover the butyl acrylate that has not participated in the reaction, thereby obtaining the dehydrated castor oil adduct.

[0046] 148 g of isobutyl alcohol (2 mol) was weighed and added to a three-necked flask of a reflux condenser, and 3.4 g of sodium methoxide (0.5% by weight) was added to the three-necked flask, the three-necked flask was heated, and then 530 g of dehydrated castor oil adduct (0.5 mol) was added to increase the reaction temperature of the dehydrated castor oil adduct and the isobutyl alcohol, and the two were subjected to transesterification reaction under mechanical stirring, and the reaction was terminated when no water was generated.

[0047] After the reaction is completed, the excess isobutanol is recovered under reduced pressure and vacuum, and the mixture is allowed to stand until stratification, and the glycerol in the lower layer is separated to obtain a mixture of dibasic acid diester and fatty acid isobutyl ester; the dibasic acid butyl ester and fatty acid butyl ester are subjected to reduced pressure distillation at 220°C to distill out fatty acid butyl ester to obtain the dibasic acid diester product.

[0048] After measurement, the kinematic viscosity of the obtained dibasic acid diester base oil product is 39 mm 2 / s, pour point is -41℃, acid value is 0.02mgKOH / g, breakdown voltage is 77Kv, and dielectric loss is 0.02.

[0049] Embodiment 3

[0050] 1000 g of dehydrated castor oil (1.07 mol) and 2.0 g of iodine (mass fraction 0.2%) were added to an autoclave, nitrogen was introduced into the autoclave, air was exhausted, the autoclave was heated to 230° C. in a sealed state, the pressure in the autoclave reached at least 1.0 MPa, 3.64 mol of isooctyl methacrylate (720 g) was uniformly injected into the autoclave using a high-pressure constant-current pump, the amount of isooctyl methacrylate being 3.4 times the amount of the dehydrated castor oil substance, and the pressure was kept constant for the next 2 hours. The autoclave was then cooled and decompressed to obtain a mixture of dehydrated castor oil adduct and isooctyl methacrylate.

[0051] The mixture of the dehydrated castor oil adduct and isooctyl methacrylate obtained above is subjected to reduced pressure vacuum distillation operation to recover isooctyl methacrylate that has not participated in the reaction, thereby obtaining the dehydrated castor oil adduct.

[0052] 260 g of octanol (2 mol) was weighed and added to a three-necked flask of a reflux condenser, and 4.9 g of sodium methoxide (0.6% by weight) was added to the three-necked flask, the three-necked flask was heated, and then 565 g of dehydrated castor oil adduct (0.5 mol) was added to increase the reaction temperature of the dehydrated castor oil adduct and octanol, and the two were subjected to ester exchange reaction under mechanical stirring, and the reaction was terminated when no water was generated.

[0053] After the reaction is completed, the excess octanol is recovered by vacuum pressure, and the mixture is allowed to stand until layers are separated. The glycerin in the lower layer is separated to obtain a mixture of dibasic acid diesters and fatty acid isooctyl esters. The dibasic acid diesters and fatty acid isooctyl esters are subjected to vacuum distillation at 230°C to distill out fatty acid isooctyl esters to obtain dibasic acid diester products.

[0054] After measurement, the kinematic viscosity of the obtained dibasic acid diester base oil product is 58 mm 2 / s, pour point is -49℃, acid value is 0.02mgKOH / g, breakdown voltage is 88Kv, and dielectric loss is 0.02.

[0055] Embodiment 4

[0056] 1000 g of dehydrated castor oil (1.07 mol) and 2.5 g of iodine (mass fraction 0.25%) were added to an autoclave, nitrogen was introduced into the autoclave, air was exhausted, the autoclave was heated to 240° C. in a sealed state, the pressure in the autoclave reached at least 1.0 MPa, 3.85 mol of 708 g of isooctyl acrylate was uniformly injected into the autoclave using a high-pressure constant-current pump, the amount of isooctyl acrylate being 3.6 times the amount of the dehydrated castor oil substance, and the pressure was kept constant for the next 3 hours. The autoclave was then cooled and decompressed to obtain a mixture of dehydrated castor oil adduct and isooctyl acrylate.

[0057] The mixture of the dehydrated castor oil adduct and isooctyl acrylate obtained above is subjected to reduced pressure vacuum distillation operation to recover the isooctyl acrylate that has not participated in the reaction, thereby obtaining the dehydrated castor oil adduct.

[0058] 260 g of 2 mol of isooctyl alcohol was weighed and added to a three-necked flask of a reflux condenser, and 6.55 g of sodium methoxide (0.8% of the total mass) was added to the three-necked flask, the three-necked flask was heated, and then 558 g of 0.5 mol of dehydrated castor oil adduct was added, the reaction temperature of the dehydrated castor oil adduct and the isooctyl alcohol was increased, and the two were subjected to ester exchange reaction under mechanical stirring, and the reaction was terminated when no water was generated.

[0059] After the reaction is completed, the excess isooctyl alcohol is recovered under reduced pressure and vacuum, and the mixture is allowed to stand until layers are separated, and the glycerin in the lower layer is separated to obtain a mixture of dibasic acid diesters and fatty acid isooctyl esters; the dibasic acid diesters and fatty acid isooctyl esters are subjected to reduced pressure distillation at 240°C to distill out the fatty acid isooctyl esters to obtain dibasic acid diester products.

[0060] After measurement, the kinematic viscosity of the obtained dibasic acid diester base oil product is 56 mm 2 / s, pour point is -54℃, acid value is 0.02mgKOH / g, breakdown voltage is 81Kv, and dielectric loss is 0.02.

[0061] Embodiment 5

[0062] 1000 g of dehydrated castor oil (1.07 mol) and 3.0 g of iodine (mass fraction 0.3%) were added to an autoclave, nitrogen was introduced into the autoclave, air was exhausted, the autoclave was heated to 180° C. in a sealed state, the pressure in the autoclave reached at least 1.0 MPa, 4.01 mol of isobutyl acrylate (520 g) was uniformly injected into the autoclave using a high-pressure constant-current pump, the amount of isobutyl acrylate being 3.8 times the amount of the dehydrated castor oil substance, and the pressure was kept constant for 1 hour thereafter. The autoclave was then cooled and decompressed to obtain a mixture of dehydrated castor oil adduct and isobutyl acrylate.

[0063] The mixture of the dehydrated castor oil adduct and isobutyl acrylate obtained above is subjected to reduced pressure vacuum distillation operation to recover the isobutyl acrylate that has not participated in the reaction, thereby obtaining the dehydrated castor oil adduct.

[0064] 148 g of isobutyl alcohol (2 mol) was weighed and added to a three-necked flask of a reflux condenser, and 3.43 g of sodium methoxide (0.5% by weight) was added to the three-necked flask, the three-necked flask was heated, and then 537 g of dehydrated castor oil adduct (0.5 mol) was added to increase the reaction temperature of the dehydrated castor oil adduct and the isobutyl alcohol, and the two were subjected to transesterification reaction under mechanical stirring, and the reaction was terminated when no water was generated.

[0065] After the reaction is completed, the excess isobutanol is recovered under reduced pressure and vacuum, and the mixture is allowed to stand until layers are separated, and the glycerol in the lower layer is separated to obtain a mixture of dibasic acid diesters and fatty acid isobutyl esters; the dibasic acid diesters and fatty acid isobutyl esters are subjected to reduced pressure distillation at 230°C to distill out fatty acid isobutyl ester to obtain a dibasic acid diester product.

[0066] After measurement, the kinematic viscosity of the obtained dibasic acid diester base oil product is 30 mm 2 / s, pour point is -48℃, acid value is 0.02mgKOH / g, breakdown voltage is 75Kv, and dielectric loss is 0.02.

[0067] Embodiment 6

[0068] 1000 g of dehydrated castor oil (1.07 mol) and 3.0 g of iodine (mass fraction 0.3%) were added to an autoclave, nitrogen was introduced into the autoclave, air was exhausted, the autoclave was heated to 200° C. in a sealed state, the pressure in the autoclave reached at least 1.0 MPa, 4.28 mol of octyl acrylate (787 g) was uniformly injected into the autoclave by a high-pressure constant-current pump, the amount of octyl acrylate being 4 times the amount of the dehydrated castor oil substance, and the pressure was kept constant for the next 2 hours. The autoclave was then cooled and decompressed to obtain a mixture of dehydrated castor oil adduct and octyl acrylate.

[0069] The mixture of the dehydrated castor oil adduct and octyl acrylate obtained above is subjected to reduced pressure vacuum distillation operation to recover the octyl acrylate that has not participated in the reaction to obtain the dehydrated castor oil adduct.

[0070] 148 g of butanol (2 mol) was weighed and added to a three-necked flask of a reflux condenser, and 7.06 g of sodium methoxide (1.0% by weight) was added to the three-necked flask, the three-necked flask was heated, and then 558 g of dehydrated castor oil adduct (0.5 mol) was added to increase the reaction temperature of the dehydrated castor oil adduct and butanol, and the two were subjected to ester exchange reaction under mechanical stirring, and the reaction was terminated when no water was generated.

[0071] After the reaction is completed, the excess butanol is recovered under reduced pressure and vacuum, and the mixture is allowed to stand until layers are separated, and the glycerol in the lower layer is separated to obtain a mixture of dibasic acid diesters and fatty acid butyl esters; the dibasic acid diesters and fatty acid butyl esters are subjected to reduced pressure distillation at 210°C to distill out fatty acid butyl ester to obtain a dibasic acid diester product.

[0072] After measurement, the kinematic viscosity of the obtained dibasic acid diester base oil product is 41 mm 2 / s, pour point is -52℃, acid value is 0.02mgKOH / g, breakdown voltage is 75Kv, and dielectric loss is 0.02.

[0073] Embodiment 7

[0074] 1000 g of dehydrated castor oil (1.07 mol) and 2.5 g of iodine (mass fraction 0.25%) were added to an autoclave, nitrogen was introduced into the autoclave, air was exhausted, the autoclave was heated to 190° C. in a sealed state, the pressure in the autoclave reached at least 1.0 MPa, 3.745 mol of isobutyl methacrylate (532 g) was uniformly injected into the autoclave using a high-pressure constant-current pump, the amount of isobutyl methacrylate being 3.5 times the amount of the dehydrated castor oil, and the pressure was kept constant for the next 2 hours. The autoclave was then cooled and decompressed to obtain a mixture of dehydrated castor oil adduct and isobutyl methacrylate.

[0075] The mixture of the dehydrated castor oil adduct and isobutyl methacrylate obtained above is subjected to reduced pressure vacuum distillation operation to recover the isobutyl methacrylate that has not participated in the reaction, thereby obtaining the dehydrated castor oil adduct.

[0076] 260 g of octanol (2 mol) was weighed and added to a three-necked flask of a reflux condenser, and 5.58 g of sodium methoxide (0.7% by weight) was added to the three-necked flask, the three-necked flask was heated, and then 537 g of dehydrated castor oil adduct (0.5 mol) was added to increase the reaction temperature of the dehydrated castor oil adduct and butanol, and the two were subjected to ester exchange reaction under mechanical stirring, and the reaction was terminated when no water was generated.

[0077] After the reaction is completed, the excess butanol is recovered under reduced pressure and vacuum, and the mixture is allowed to stand until layers are separated, and the glycerol in the lower layer is separated to obtain a mixture of dibasic acid diesters and fatty acid octyl esters; the dibasic acid diesters and fatty acid octyl esters are subjected to reduced pressure distillation at 230°C to distill out fatty acid octyl esters to obtain dibasic acid diester products.

[0078] After measurement, the kinematic viscosity of the obtained dibasic acid diester base oil product is 55 mm 2 / s, pour point is -45℃, acid value is 0.02mgKOH / g, breakdown voltage is 77Kv, and dielectric loss is 0.02.

[0079] Embodiment 8

[0080] 1000 g of dehydrated castor oil (1.07 mol) and 2.0 g of iodine (mass fraction 0.2%) were added to an autoclave, nitrogen was introduced into the autoclave, air was exhausted, the autoclave was heated to 200° C. in a sealed state, the pressure in the autoclave reached at least 1.0 MPa, 3.64 mol of octyl methacrylate (720 g) was uniformly injected into the autoclave by a high-pressure constant-current pump, the amount of octyl methacrylate being 3.4 times the amount of the dehydrated castor oil, and the pressure was kept constant for 2.5 hours thereafter. The autoclave was then cooled and decompressed to obtain a mixture of dehydrated castor oil adduct and octyl methacrylate.

[0081] The mixture of the dehydrated castor oil adduct and octyl methacrylate obtained above is subjected to reduced pressure vacuum distillation operation to recover the octyl methacrylate that has not participated in the reaction, thereby obtaining the dehydrated castor oil adduct.

[0082] 260 g of 2 mol of isooctyl alcohol was weighed and added to a three-necked flask of a reflux condenser, and 7.43 g of sodium methoxide (0.9% of the total mass) was added to the three-necked flask, the three-necked flask was heated, and then 565 g of 0.5 mol of dehydrated castor oil adduct was added, the reaction temperature of the dehydrated castor oil adduct and the isooctyl alcohol was increased, and the two were subjected to ester exchange reaction under mechanical stirring, and the reaction was terminated when no water was generated.

[0083] After the reaction is completed, the excess isooctyl alcohol is recovered under reduced pressure and vacuum, and the mixture is allowed to stand until layers are separated, and the glycerin in the lower layer is separated to obtain a mixture of dibasic acid diesters and fatty acid isooctyl esters; the dibasic acid diesters and fatty acid isooctyl esters are subjected to reduced pressure distillation at 240°C to distill out the fatty acid isooctyl esters to obtain dibasic acid diester products.

[0084] After measurement, the kinematic viscosity of the obtained dibasic acid diester base oil product is 60 mm 2 / s, pour point is -40℃, acid value is 0.02mgKOH / g, breakdown voltage is 78Kv, and dielectric loss is 0.02.

[0085] The process has been shown in practice examples using various raw materials to have stable product quality. The invention uses nitrogen to create a high pressure state in an autoclave, uses a relatively small amount of iodine as a catalyst, and uses a high pressure constant flow pump to uniformly inject an allyl compound into the autoclave, so that the mass transfer between iodine and the allyl compound is accelerated, and the linoleic acid and oleic acid components in the dehydrated castor oil and the allyl compound can undergo conjugation and Diels-Alder addition reaction more quickly, thereby obtaining a high yield of dibasic acid monoester adducts.

[0086] The technical solution has obtained the target product, dibasic acid diester, through a large number of experiments. The present invention uses nitrogen to form a high pressure state in an autoclave, uses a small amount of iodine as a catalyst, uses a high-pressure constant-current pump to uniformly inject an allyl compound into the autoclave containing dehydrated castor oil, uses linoleic acid and oleic acid components in the dehydrated castor oil to synthesize dehydrated castor oil adducts with the allyl compound, and the adducts directly undergo ester exchange reactions with suitable mono-fatty alcohols to obtain a variety of dibasic acid diester base oils with a six-membered ring structure.

[0087] The product obtained through the process of this scheme has low cost and high biodegradability, and belongs to the green plant-based ester base oil. This type of dibasic acid diester has greatly improved stability due to the iodine value (reduction of unsaturated bonds). At the same time, this type of value has good pour point, viscosity, and electrical properties. It can be widely used in hydraulic oil, metalworking fluid, transformer oil and other fields, and has good effectiveness. After testing, the kinematic viscosity of the product is 30-60mm 2 / s, pour point is -40~-55℃, acid value is less than 0.02mgKOH / g, dielectric loss is less than 0.02, and breakdown voltage is greater than 75Kv.

[0088] The dibasic acid diester obtained by using this technical process can meet the market's various demands for biodegradable ester base oils. For example, it can be used as a processing fluid such as a cutting fluid, or as an important component of a hydraulic oil. Furthermore, due to its lower pour point and lower viscosity, it can be used as the main component of a vegetable transformer oil.

[0089] The above is only an embodiment of the present invention, and the common knowledge such as the known specific structure and characteristics in the scheme is not described in detail here. It should be pointed out that for those skilled in the art, several deformations and improvements can be made without departing from the structure of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A process for synthesizing a dibasic acid diester from dehydrated castor oil and an allyl compound, characterized in that: The steps include: S1: In an autoclave containing dehydrated castor oil, a certain amount of iodine is added into the autoclave and nitrogen is introduced, the temperature is raised to 180-240° C., a stirrer is turned on, and an allyl compound is uniformly injected into the autoclave using a high-pressure constant-current pump, and the reaction is continued for 1-3 hours, and the decompression is reduced to obtain a mixture of dehydrated castor oil adduct and allyl compound; S2: performing a reduced pressure vacuum distillation operation on the mixture obtained in step S1 to remove the allyl compound that has not participated in the reaction, thereby obtaining a dehydrated castor oil adduct; S3: adding the dehydrated castor oil adduct obtained in step S2 to a three-necked flask of a reflux condenser, and adding mono fatty alcohol to the three-necked flask, using sodium methoxide as an alkaline catalyst, the dehydrated castor oil adduct and the mono fatty alcohol undergo an ester exchange reaction under the catalysis of sodium methoxide, and recovering excess mono fatty alcohol under reduced pressure and vacuum, and then standing until stratification, separating glycerol, and obtaining a mixture of dibasic acid diesters and fatty acid esters; S4: performing a distillation operation using a vacuum distillation apparatus, slowly injecting the mixture of the dibasic acid diester and the fatty acid ester produced in step S3 into the vacuum distillation apparatus, and separating the dibasic acid diester and the fatty acid ester by distillation to obtain a dibasic acid diester base oil.

2. A process for synthesizing a dibasic acid diester from dehydrated castor oil and an allyl compound according to claim 1, characterized in that: In steps S1 and S2, the allyl compound includes one of butyl acrylate, isobutyl acrylate, octyl acrylate, isooctyl acrylate, butyl methacrylate, isobutyl methacrylate, octyl methacrylate, and isooctyl methacrylate.

3. A process for synthesizing a dibasic acid diester from dehydrated castor oil and an allyl compound according to claim 1, characterized in that: In step S1, the dehydrated castor oil is industrial dehydrated castor oil.

4. A process for synthesizing a dibasic acid diester from dehydrated castor oil and an allyl compound according to claim 2, characterized in that: In step S1, the iodine added is 0.1-0.3%wt of the mass of the dehydrated castor oil.

5. A process for synthesizing a dibasic acid diester from dehydrated castor oil and an allyl compound according to claim 2, characterized in that: In step S1, the pressure of the nitrogen filling is maintained at 1.0 MPa.

6. A process for synthesizing a dibasic acid diester from dehydrated castor oil and an allyl compound according to claim 1, characterized in that: In step S3, the monoaliphatic alcohol is one of butanol, isobutanol, octanol and isooctyl alcohol.

7. A process for synthesizing a dibasic acid diester from dehydrated castor oil and an allyl compound according to claim 6, characterized in that: The amount of the mono fatty alcohol substance added to the three-necked flask in step S3 is 3 to 4 times the amount of the dehydrated castor oil adduct.

8. A process for synthesizing a dibasic acid diester from dehydrated castor oil and an allyl compound according to claim 1, characterized in that: In step S3, the amount of sodium methoxide used is 0.2-1.0%wt of the total material amount.

9. A process for synthesizing a dibasic acid diester from dehydrated castor oil and an allyl compound according to claim 7, characterized in that: The vacuum degree during the reduced pressure distillation operation is 0.05MPa to 0.099MPa.

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