Disclosure of Invention
The invention aims to provide a synthetic method of complex ester type refrigerator oil.
In order to achieve the technical purpose, the invention adopts the following technical scheme:
a synthetic method of complex ester type refrigerator oil comprises the steps of adding polypentaerythritol with more than 5 hydroxyl groups, dibasic acid and a catalyst into raw material polyhydric alcohol to complete a first esterification reaction, then adding monobasic fatty acid with a carbon chain length of 4-9 to complete a second esterification reaction, and refining a product to obtain the complex ester type refrigerator oil.
As a further improvement of the invention, the raw material polyol is one or more of neopentyl glycol, trimethylolpropane or pentaerythritol.
As a further development of the invention, the polypentaerythritol having a hydroxyl number of more than 5 is dipentaerythritol and/or tripentaerythritol.
As a further improvement of the invention, the first esterification reaction and the second esterification reaction are carried out under the protection of inert gas.
As a further improvement of the invention, the adding amount of the polypentaerythritol with the hydroxyl number more than 5 is 3-15% of the mass of the raw material polyol; preferably 5 to 10%.
As a further improvement of the method, the temperature of the first-step esterification reaction and the second-step esterification reaction is 180-240 ℃.
As a further improvement of the invention, the catalyst is one or more of solid super acid, titanate and stannous salt.
As a further improvement of the invention, after the two-step esterification reaction is completed, the reaction system is cooled and then added with the adsorbent, and the complex ester type refrigerating machine oil product is obtained through adsorption, vacuum degassing and filter pressing.
As a further improvement of the method, after the two-step esterification reaction is completed, the reaction system is cooled to 50-100 ℃, and then an adsorbent is added for adsorption reaction.
As a further improvement of the invention, the adsorbent is one or more of activated clay, activated carbon, diatomite, alkaline bleaching earth and alumina.
As a further improvement of the invention, the temperature of the vacuum degassing is 80-130 ℃, and the vacuum degree is-0.090-0.100 MPa.
As a further improvement of the invention, the monoacid with the carbon chain length of 4-9 comprises but is not limited to n-pentanoic acid, n-heptanoic acid, isononanoic acid and isooctanoic acid.
The invention also aims to provide the complex ester type refrigerator oil prepared by the method. The complex ester type refrigerator oil prepared by the method has good viscosity-temperature performance and high stability.
According to the method, the polypentaerythritol with more than 5 hydroxyl groups in a certain proportion is added into the raw material polyol used in the reaction, so that the viscosity-temperature performance of the product can be obviously improved under the condition that the application performance of the product is basically unchanged, the esterification reaction is carried out on the new mixed polyol, the dibasic acid and the C4-9 monobasic fatty acid step by step, the product is refined and then the refrigerator oil product with good viscosity-temperature performance and high stability is finally synthesized, and meanwhile, the product yield is at a higher level.
Detailed Description
In order to better illustrate the invention, we will cite the following examples, but the invention is not limited to the following examples.
Example 1
This example specifically illustrates an apparatus used in the synthesis reaction of the present invention, which comprises, as shown in fig. 2, an esterification reaction vessel 1, a condensing apparatus 2, a waste liquid receiving apparatus 3, a pump i 4, a finished product receiving apparatus 5, 6-two-step esterification raw material acid storage tank, 7-a refining reaction vessel, and 8-a pump ii.
The device used in the embodiment is shown in fig. 2, an esterification reaction kettle 1, a refining reaction kettle 7 and a finished product receiving device 5 are connected in sequence according to the sequence of working procedures, a pump I4 and a pump II 8 are used as material pumps to pump products into the next reaction kettle/finished product receiving device, a two-step esterification raw material acid storage tank 6 is connected with a feed inlet of the esterification reaction kettle 1, raw material acid of the second step of esterification reaction, namely, monobasic fatty acid with the carbon chain length of 4-9, is stored, and the materials are fed into the esterification reaction kettle 1 after the first step of esterification reaction is completed. The upper part of the esterification reaction kettle 1 is connected with a condensing device 2, the gas escaping from the reaction is condensed and then phase-separated, the oil phase is sent into the esterification reaction kettle 1 to continue to take part in the reaction, and the water phase is sent into a waste liquid receiving device 3.
The crude synthetic ester base oil is sent into a refining reaction kettle 7 through a pump I4, an adsorbent is added for adsorption, then vacuum pressure reduction degassing and precise filtration are carried out, and a product is sent into a finished product receiving device 5 through a pump II 8.
Example 2
Referring to fig. 1, the process flow for synthesizing the polyol complex ester i by taking pentaerythritol, dipentaerythritol, adipic acid and isooctanoic acid as raw materials is as follows:
(1) adding 12.2kg of pentaerythritol, 1.1kg of dipentaerythritol, 9.6kg of adipic acid and a proper amount of catalyst into an esterification reaction kettle, wherein the dosage of the catalyst is 0.001 mass of the pentaerythritol, and stirring and heating to 220 ℃ under the protection of nitrogen;
(2) keeping the temperature for reaction until the acid value of the system is less than 3.0, adding 38.0kg of isooctanoic acid, and continuing the esterification reaction at 220 ℃; obtaining crude pentaerythritol adipate isooctoate;
(3) keeping the temperature to react until the acid value of the system is less than 1.0, cooling to the adsorption temperature, adding a specified amount of composite adsorbent, refining and adsorbing for 2 hours, and precisely performing filter pressing to obtain the finished product of the polyol composite ester I.
The acid value of the polyol complex ester I product is 0.03 mgKOH/g, the hydroxyl value is 2.7 mgKOH/g, and the yield is 89.55 percent. The viscosity of the obtained product at 40 ℃ is 70-300 cSt.
Example 3
Referring to fig. 1, the process flow for synthesizing the polyol complex ester ii by using neopentyl glycol, tripentaerythritol, adipic acid and isononanoic acid as raw materials is as follows:
according to the operation of the embodiment 1, 15.9kg of neopentyl glycol, 1.1kg of tripentaerythritol, 13.1kg of adipic acid and a catalyst are added into an esterification reaction kettle, 47.4kg of isononanoic acid is added after one-step esterification is completed, and the heat preservation reaction is continued; and after the two-step esterification is finished, refining to obtain a finished product.
The acid value of the polyol complex ester II product is 0.04mgKOH/g, the hydroxyl value is 3.5 mgKOH/g, and the reaction yield is 88.74 percent. The viscosity of the obtained product at 40 ℃ is 80-400 cSt.
Example 4
Referring to fig. 1, the process flow for synthesizing the polyol complex ester iii by taking pentaerythritol, dipentaerythritol, tripentaerythritol, sebacic acid, and n-valeric acid as raw materials is as follows:
according to the operation of the embodiment 1, 18.3kg of pentaerythritol, 0.6kg of dipentaerythritol, 0.6kg of tripentaerythritol, 18.6kg of sebacic acid and a catalyst are added into an esterification reaction kettle, 40.8kg of n-valeric acid is added after one-step esterification is completed, and the heat preservation reaction is continued; and after the two-step esterification is finished, refining to obtain a finished product.
The acid value of the polyol complex ester III product is 0.02 mgKOH/g, the hydroxyl value is 4.1mgKOH/g, and the yield is 88.24%. The viscosity of the obtained product at 40 ℃ is 60-480 cSt.
Example 5
Referring to fig. 1, the technological process for synthesizing the polyol complex ester iv by using trimethylolpropane, tripentaerythritol, sebacic acid, and n-heptanoic acid as raw materials is as follows:
according to the operation of the embodiment 1, 7.3kg of trimethylolpropane, 1.1kg of tripentaerythritol, 8.1kg of sebacic acid and a catalyst are added into an esterification reaction kettle, 26.1kg of n-heptanoic acid is added after one-step esterification is completed, and the heat preservation reaction is continued; and after the two-step esterification is finished, refining to obtain a finished product.
The acid value of the polyol complex ester IV product is 0.23mgKOH/g, the hydroxyl value is 7.1 mgKOH/g, and the yield is 86.55%. The viscosity of the resulting product is from 80 to 500cSt at 40 ℃.
Example 6
Referring to fig. 1, the process flow for synthesizing the polyol complex ester v by taking neopentyl glycol, dipentaerythritol, adipic acid and n-heptanoic acid as raw materials is as follows:
according to the operation of the embodiment 1, 20.0kg of neopentyl glycol, 0.6kg of dipentaerythritol, 8.02kg of adipic acid and a catalyst are added into an esterification reaction kettle, 40.2kg of n-heptanoic acid is added after one-step esterification is completed, and the heat preservation reaction is continued; and after the two-step esterification is finished, refining to obtain a finished product.
The acid value of the polyol complex ester V product is 0.03 mgKOH/g, the hydroxyl value is 4.3 mgKOH/g, and the yield is 86.71%. The viscosity of the resulting product is from 30 to 300cSt at 40 ℃.
Example 7
Referring to fig. 1, the process flow for synthesizing the polyol complex ester vi by using neopentyl glycol, tripentaerythritol, adipic acid and isononanoic acid as raw materials is as follows:
according to the operation of example 1, 17.3kg of neopentyl glycol, 6.7kg of pentaerythritol, 1.2kg of dipentaerythritol, 12.66kg of adipic acid and a catalyst are added into an esterification reaction kettle, 69.48kg of isononanoic acid is added after one-step esterification is completed, and the heat preservation reaction is continued; and after the two-step esterification is finished, refining to obtain a finished product.
The acid value of the polyol complex ester VI product is 0.04mgKOH/g, the hydroxyl value is 3.0 mgKOH/g, and the yield is 86.97%. The viscosity of the resulting product is 20-400cSt at 40 ℃.
Example 8
Referring to fig. 1, the process flow for synthesizing the polyol complex ester vii by using neopentyl glycol, tripentaerythritol, adipic acid and n-butyric acid as raw materials is as follows:
according to the operation of the embodiment 1, 12.0kg of neopentyl glycol, 1.2kg of dipentaerythritol, 5.83kg of adipic acid and a catalyst are added into an esterification reaction kettle, 18.1kg of n-butyric acid is added after one-step esterification is completed, and the heat preservation reaction is continued; and after the two-step esterification is finished, refining to obtain a finished product.
The acid value of the polyol complex ester VII product is 0.03 mgKOH/g, the hydroxyl value is 5.0 mgKOH/g, and the yield is 88.22%. The viscosity of the resulting product is from 30 to 480cSt at 40 ℃.