阅读说明：本技术 一种复酯型冷冻机油及其合成方法 (Complex ester type refrigerator oil and synthetic method thereof ) 是由 时晨 朱兵 孟思凡 付鑫 袁鹏 曹昕 于 2020-12-30 设计创作，主要内容包括：本发明涉及一种复酯型冷冻机油合成方法,在原料多元醇中加入羟基数多于5的聚季戊四醇、二元酸和催化剂完成第一步酯化反应,后加入碳链长度为4～9的一元脂肪酸完成第二步酯化反应,产物精制后获取所述复酯型冷冻机油。本发明的方法通过向反应所用向原料多元醇中加入一定比例羟基数多于5的聚季戊四醇,可在保证产品应用性能基本不变的条件下,显著改善其粘温性能,将新的混合多元醇与二元酸、C4～9一元脂肪酸分步发生酯化反应,经精制后处理,最终合成粘温性能好、稳定性高的冷冻机油产品,同时产品收率处于较高水平。(The invention relates to a method for synthesizing complex ester type refrigerating machine oil, which comprises the steps of adding polypentaerythritol with more than 5 hydroxyl groups, dibasic acid and a catalyst into raw material polyalcohol 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 refrigerating machine oil. 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.)

1. A method for synthesizing complex ester type refrigerating machine oil is characterized in that polypentaerythritol with more than 5 hydroxyl groups, dibasic acid and a catalyst are added into raw material polyalcohol to complete a first esterification reaction, then, monobasic fatty acid with a carbon chain length of 4-9 is added to complete a second esterification reaction, and a product is refined to obtain the complex ester type refrigerating machine oil.

2. The method of claim 1, wherein the feedstock polyol is one or more of neopentyl glycol, trimethylolpropane, or pentaerythritol.

3. The process according to claim 1, wherein the polypentaerythritol having a hydroxyl number of more than 5 is dipentaerythritol and/or tripentaerythritol.

4. The method of claim 1, wherein the first and second esterification reactions are carried out under an inert gas blanket.

5. The method according to claim 1, wherein the 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%.

6. The method according to claim 1, wherein the first and second esterification reaction temperatures are 180 to 240 ℃.

7. The method of claim 1, wherein the catalyst is one or more of a solid super acid, a titanate, a stannous salt.

8. The method as claimed in claim 1, wherein after the two-step esterification reaction is completed, the reaction system is cooled, and then an adsorbent is added, and the complex ester type refrigerator oil product is obtained through adsorption, vacuum degassing and filter pressing.

9. The method according to claim 1, 6 or 8, wherein after the two esterification steps are completed, the reaction system is cooled to 50-100 ℃, and then an adsorbent is added for adsorption reaction.

10. A complex ester refrigerator oil prepared by the method of any one of claims 1 to 9.

Technical Field

The invention relates to the technical field of chemical industry, in particular to compound ester type refrigerator oil and a synthetic method thereof.

Background

A polyol complex ester refrigerator oil is a high-grade synthetic polyester lubricating oil. The lubricating oil can be used as special lubricating oil for refrigerating type compression devices and applied to lubrication, sealing and cooling of various refrigerators. The refrigerator oil has good compatibility, reliable lubricating property, excellent thermal stability, chemical stability, electrical insulation property and material compatibility with HFCs refrigerant, and good safety and environmental protection performance, and has become the first choice lubricating oil for the compatibility of the HFCs refrigerant. The refrigerant is a crucial component for determining and influencing the refrigeration function and effect in a refrigeration system using HFCs as a refrigerant.

In the prior art, various polyol complex ester refrigerating machine oil preparation processes are available, and the process or product quality is improved by different optimization means, for example, four patents of CN105017014A preparation process of neopentyl polyol heptanoate, CN105001082A preparation process of neopentyl polyol laurate, CN104945247A preparation process of neopentyl polyol oleate and CN105130800A preparation process of neopentyl polyol mixed acid ester are calculated by theoretical molar ratio and combined with empirical molar ratio of multiple batches of small tests, and the optimal initial feeding ratio is researched. CN102030638A A process for preparing neopentyl polyol octadecanoate comprises preparing neopentyl polyol and octadecanoic acid as raw materials to obtain neopentyl polyol octadecanoate crude product, and performing molecular distillation to obtain product with low acid value and low chromaticity, wherein the process focuses on the conditions of molecular distillation. The preparation method comprises the following steps of carrying out two-step esterification reaction on neopentyl glycol, trimethylolpropane, neopentyl glycol, C5-12 dibasic fatty acid and C14-20 monobasic fatty acid serving as raw materials to obtain a product; CN104145006B working fluid composition for refrigerator, refrigerator oil and manufacturing method thereof, which adopts neopentyl polyol composition as reaction raw material and mainly comprises neopentyl polyol, trimethylolpropane and pentaerythritol. CN107760407A A preparation method of compound ester for water-based lubricant, selecting single pentaerythritol as raw material alcohol, long carbon chain oleic acid as raw material acid, and xylene as water-carrying agent, synthesizing pentaerythritol octanedioate oleate step by step; CN105061202A A method and catalyst for catalytically synthesizing neopentyl polyol fatty acid ester, wherein the process selects a special catalyst and synthesizes an esterified product by an ester exchange method.

As the above-listed conventional process for synthesizing polyol complex esters, polyols having different hydroxyl numbers are selected as starting materials according to the grades of the synthesized polyol complex esters, and commonly used polyols are neopentyl glycol, trimethylolpropane and pentaerythritol, and the hydroxyl numbers of the polyols are all less than 5. The method in the prior art usually reduces certain viscosity-temperature performance of the product to ensure that the intersolubility application effect of the complex ester type refrigerating machine oil finally used in the refrigerant meets the requirement.

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.

Drawings

FIG. 1 is a process flow diagram of the process of the present invention.

FIG. 2 is a schematic diagram of the esterification process of the experimental apparatus of the present invention, in which:

1-esterification reaction kettle, 2-condensing unit, 3-waste liquid receiving device, 4-pump I, 5-finished product receiving device, 6-two-step esterification raw material acid storage tank, 7-refining reaction kettle, and 8-pump II.

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 ℃.