Polymaleated lactone sophorolipid antirust agent for electric vehicle cooling liquid and preparation method of polymaleated lactone sophorolipid antirust agent

Abstract

The invention discloses a polymaleated lactone type sophorolipid antirust agent for electric vehicle cooling liquid and a preparation method thereof.The polymaleated lactone type sophorolipid antirust agent is prepared from raw material lactone type sophorolipid, and the preparation method specifically comprises the steps that firstly, the lactone type sophorolipid and maleic anhydride are subjected to an anhydride ring-opening reaction to obtain a polymaleated lactone type sophorolipid antirust agent; and carrying out dehydration esterification on carboxyl residues in the obtained intermediate and lactone type sophorolipid, so as to obtain the polymaleated lactone type sophorolipid. According to the addition proportion of the lactone type sophorolipid and the maleic anhydride, the performance of the finally obtained poly-maleated lactone type sophorolipid is adjusted from the molecular structure, and the obtained poly-maleated lactone type sophorolipid has extremely low conductivity and better anti-corrosion performance on various metals on the basis of an original anti-rust agent.

Description

Technical Field

[0001] The present invention belongs to the technical field of rust inhibitors for electric vehicle coolants, and particularly relates to a polymaleated lactone-type sophorolipid for rust prevention of electric vehicle coolants and a preparation method thereof. Background Art

[0002] The continued increase in global vehicle ownership has created a stable demand for automotive coolant, both for pre-installation on new vehicles and for routine maintenance and replacement. The global automotive coolant market was projected to reach RMB 76.355 billion in 2023, with the Chinese market reaching RMB 35.765 billion. The global market is projected to reach RMB 90.612 billion by 2029, with a projected CAGR of 2.54%.

[0003] Improved technical performance: Traditional coolants primarily focused on antifreeze and corrosion protection, but now they prioritize environmental protection, high efficiency, and long life. For example, new coolants using organic acid salt technology offer excellent corrosion protection and are more environmentally friendly. Improved formulations enhance the coolant's chemical stability at high temperatures, and some coolants are also focusing on biodegradability.

[0004] Coolants are mainly divided into various types, such as water-based coolants, organic acid coolants, silicate coolants, and anhydrous coolants. Among them, water-based coolants are the most commonly used type due to their good corrosion resistance and environmental adaptability.

[0005] As new energy vehicles (NEVs) gain market penetration, demand for high-performance coolants in their liquid cooling systems is surging. New energy vehicles typically use more coolant than traditional fuel vehicles. For example, low- and mid-range NEVs require approximately 25L of coolant, while high-end models require up to 60L. Traditional fuel vehicles typically use only 4-6L.

[0006] Electric vehicles' battery systems and electrical components contain high-voltage circuits, which can cause minute current leaks. If high-conductivity coolant is used, contact with the circuits could cause current to flow through the cooling system, leading to electrical failures such as short circuits, arcing, and fires, seriously threatening vehicle safety. Low-conductivity coolant, however, typically has a much lower conductivity than traditional coolants. This effectively prevents current from flowing through the coolant, reducing the risk of electrical failure and improving battery system safety.

[0007] Rust inhibitors for fuel vehicle coolants include the following four categories: Inorganic salt-based rust inhibitors (IAT, Inorganic Acid Technology), whose main ingredients include silicates, phosphates, nitrates, nitrites, molybdates, etc., such as the water-based rust-proof grinding coolant for automobile connecting rods disclosed in patent application 201310590914.3, and its preparation method and application; Organic acid-based rust inhibitors (OAT, Organic Acid Technology), whose main ingredients include organic carboxylates such as sebacic acid, 2-ethylhexanoic acid, and octanoic acid, such as the emulsion-type environmentally friendly cutting fluid disclosed in patent application 201511009482.8; Hybrid Organic Acid Technology (HOAT, Hybrid Organic Acid Technology), whose main ingredients include organic acid + a small amount of inorganic salt (such as silicate), such as the new automobile coolant disclosed in patent application 201210172177.0; Phosphate-based rust inhibitors (POAT, Phosphated Organic Acid Technology), whose main ingredients include organic acid + a small amount of inorganic salt (such as silicate); Technology), main ingredients: organic acid + phosphate, such as the anti-corrosion automobile antifreeze disclosed in patent application 201510972734.0.

[0008] However, these types of rust inhibitors will bring higher conductivity to the coolant. Therefore, it is urgent to synthesize high-efficiency rust inhibitors with low conductivity to meet the needs of electric vehicles. Summary of the Invention

[0009] To solve the above problems, the primary purpose of the present invention is to provide a polymaleated lactone-type sophorolipid rust inhibitor for electric vehicle coolant and a preparation method thereof. In the molecular design of the present invention, a lactone-type sophorolipid is selected as the initiator of the rust inhibitor for electric vehicle coolant, and an anhydride ring-opening reaction is carried out with maleic anhydride, and then the reaction intermediate is subjected to an esterification and dehydration reaction. The obtained polymaleated lactone-type sophorolipid has extremely low electrical conductivity and better rust and corrosion inhibition properties for various metals on the basis of the original rust inhibitor, especially for typical metals used in tram cooling systems. It has a good rust and corrosion inhibition effect.

[0010] Another object of the present invention is to provide a polymaleated lactone-type sophorolipid rust inhibitor for electric vehicle coolant and a preparation method thereof. The main raw material of the present invention is a glycolipid organism, which has excellent biodegradability and low toxicity, and the preparation method is simple, easy to operate, and environmentally friendly; at the same time, the preparation method is carried out under normal pressure and has low requirements on equipment production conditions.

[0011] To achieve the above objectives, the technical solutions of the present invention are as follows.

[0012] A polymaleated lactone-type sophorolipid rust inhibitor for electric vehicle coolant, wherein the polymaleated lactone-type sophorolipid is prepared by anhydride ring-opening reaction and esterification reaction of a lactone-type sophorolipid, and the lactone-type sophorolipid comprises the following general formula as shown in Chemical Formula I:

[0013]

[0014] Wherein, R1 is a C1-C18 linear or branched saturated or unsaturated hydrocarbon group; R2 is a C2-C18 linear or branched saturated or unsaturated hydrocarbon group;

[0015] The reaction is carried out according to the general formula shown in reaction equation II, and the lactone-type sophorolipid and maleic anhydride are esterified and dehydrated at a high temperature of 90°C to 200°C to obtain a polymaleated lactone-type sophorolipid;

[0016]

[0017] Furthermore, it is characterized in that R1 is a straight-chain or branched saturated or unsaturated hydrocarbon group of C1 to C3; R2 is a straight-chain or branched saturated or unsaturated hydrocarbon group of C10 to C16.

[0018] The present invention selects lactone-type sophorolipids as the initiator of the rust inhibitor for electric vehicle coolant, performs an anhydride ring-opening reaction with maleic anhydride, and then performs an esterification and dehydration reaction on the reaction intermediate to prepare a polymaleated lactone-type sophorolipid. The obtained polymaleated lactone-type sophorolipid has extremely low electrical conductivity and better anti-rust and corrosion performance on various metals on the basis of the original rust inhibitor.

[0019] The polymaleated lactone-type sophorolipid rust inhibitor for electric vehicle coolant and its preparation method achieved by the present invention include: first, subjecting the lactone-type sophorolipid and maleic anhydride to an anhydride ring-opening reaction; then, heating the obtained intermediate to 140° C. to 200° C. to carry out dehydration esterification between the carboxyl residue in the intermediate and the lactone-type sophorolipid, comprising the following steps:

[0020] Step (1), anhydride ring-opening reaction: adding lactone-type sophorolipid and maleic anhydride into a reactor, and carrying out an anhydride ring-opening reaction at 90°C to 120°C to obtain an intermediate;

[0021] Step (2), esterification reaction; the intermediate obtained in step (1) is further heated to 140°C to 200°C to carry out dehydration esterification of the carboxyl residue in the intermediate with the lactone-type sophorolipid to obtain a polymaleated lactone-type sophorolipid.

[0022] Further, in step (1), the lactone-type sophorolipid and maleic anhydride are placed in a molar ratio of (1.00-2.00): 1 in an experimental device equipped with a stirrer, a thermometer, a water separator and a condenser. The lactone-type sophorolipid and maleic anhydride are placed in a reactor, the experimental device is inerted as a whole 3 times, and finally an inert gas protection is introduced, the condenser is opened, and the anhydride ring-opening reaction is carried out at 90°C to 120°C.

[0023] Furthermore, the anhydride ring-opening reaction time is 1 to 3 hours.

[0024] Furthermore, the molar ratio of the lactone-type sophorolipid and maleic anhydride is (1.00-1.50):1, and the resulting polymaleated lactone-type sophorolipid has extremely low electrical conductivity and better anti-rust and corrosion performance on various metals based on the original rust inhibitor.

[0025] Furthermore, the inert gas is any one of nitrogen and argon.

[0026] Furthermore, in step (2), the dehydration esterification is carried out by controlling the reaction temperature to rise less than 5° C., and the esterification reaction is considered to be completed if the acid value does not change within half an hour.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] In the molecular design of the present invention, lactone-type sophorolipids are selected as the initiator of the rust inhibitor for electric vehicle coolant. The polymaleated lactone-type sophorolipids obtained by the anhydride ring-opening reaction with maleic anhydride and then the esterification and dehydration reaction of the reaction intermediate are obtained. The polymaleated lactone-type sophorolipids have extremely low electrical conductivity and better rust and corrosion inhibition properties for various metals, especially for typical metals used in tram cooling systems.

[0029] At the same time, the main raw materials of the present invention are glycolipid organisms, which have excellent biodegradability and low toxicity, and the preparation method is simple, easy to operate, and environmentally friendly; at the same time, the preparation method is carried out under normal pressure and has low requirements on equipment production conditions. DETAILED DESCRIPTION

[0030] To facilitate understanding of the present invention, the present invention will be described in more comprehensive and detailed form below in conjunction with preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments. Unless otherwise defined, all technical terms used hereinafter have the same meaning as those commonly understood by those skilled in the art. The technical terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0031] The implementation of the present invention is described in detail below with reference to specific embodiments and test examples.

[0032] Example 1.

[0033] Step (1), lactone-type sophorolipids and maleic anhydride are placed in an experimental apparatus equipped with a stirrer, a thermometer, a water separator and a condenser at a molar ratio of 1.00: 1. The experimental apparatus is inerted as a whole three times, and finally inert gas protection is introduced, the condenser is opened, and the anhydride ring-opening reaction time is 3 hours at 90 ° C.

[0034] Step (2), the intermediate obtained in step (1) is further heated to 140 ° C. to carry out dehydration esterification of the carboxyl residue in the intermediate with the lactone-type sophorolipid, and the reaction temperature is controlled to rise less than 5 ° C. The esterification reaction is considered to be completed if the acid value does not change within half an hour. The product is reddish brown and has an acid value of 32 mg·KOH / g.

[0035] The resulting product exhibits excellent rust and corrosion resistance on various metals and low electrical conductivity.

[0036] Example 2.

[0037] Step (1), lactone-type sophorolipids and maleic anhydride are placed in an experimental apparatus equipped with a stirrer, a thermometer, a water separator and a condenser at a molar ratio of 1.10:1. The experimental apparatus is inerted as a whole three times, and finally inert gas protection is introduced, the condenser is opened, and the anhydride ring-opening reaction time is 1 hour at 120 ° C.

[0038] Step (2), the intermediate obtained in step (1) is further heated to 200 ° C for dehydration esterification of the carboxyl residue in the intermediate with the lactone-type sophorolipid, and the reaction temperature is controlled to rise less than 5 ° C. The esterification reaction is considered to be completed if the acid value does not change within half an hour. The product is reddish brown and has an acid value of 23 mg·KOH / g.

[0039] The resulting product exhibits excellent rust and corrosion resistance on various metals and low electrical conductivity.

[0040] Example 3.

[0041] Step (1), lactone-type sophorolipids and maleic anhydride are placed in an experimental apparatus equipped with a stirrer, a thermometer, a water separator and a condenser at a molar ratio of 1.20: 1. The experimental apparatus is inerted as a whole three times, and finally an inert gas protection is introduced, the condenser is opened, and the anhydride ring-opening reaction time is 2.5 hours at 95 ° C.

[0042] Step (2), the intermediate obtained in step (1) is further heated to 150 ° C. to carry out dehydration esterification of the carboxyl residue in the intermediate with the lactone-type sophorolipid, and the reaction temperature is controlled to rise less than 5 ° C. The esterification reaction is considered to be completed if the acid value does not change within half an hour. The product is reddish brown and has an acid value of 21 mg·KOH / g.

[0043] The resulting product exhibits excellent rust and corrosion resistance on various metals and low electrical conductivity.

[0044] Example 4.

[0045] Step (1), lactone-type sophorolipids and maleic anhydride are placed in an experimental apparatus equipped with a stirrer, a thermometer, a water separator and a condenser at a molar ratio of 1.30:1. The experimental apparatus is inerted as a whole three times, and finally an inert gas protection is introduced, the condenser is opened, and the anhydride ring-opening reaction time is 1.5 hours at 110 ° C.

[0046] Step (2), the intermediate obtained in step (1) is further heated to 180 ° C. to carry out dehydration esterification of the carboxyl residue in the intermediate with the lactone-type sophorolipid, and the reaction temperature is controlled to rise less than 5 ° C. The esterification reaction is considered to be completed if the acid value does not change within half an hour. The product is reddish brown and has an acid value of 18 mg·KOH / g.

[0047] The resulting product exhibits excellent rust and corrosion resistance on various metals and low electrical conductivity.

[0048] Example 5.

[0049] Step (1), lactone-type sophorolipids and maleic anhydride are placed in an experimental apparatus equipped with a stirrer, a thermometer, a water separator and a condenser at a molar ratio of 1.50:1. The experimental apparatus is inerted as a whole three times, and finally an inert gas protection is introduced, the condenser is opened, and the anhydride ring-opening reaction time is 2 hours at 100 ° C.

[0050] Step (2), the intermediate obtained in step (1) is further heated to 190 ° C. to carry out dehydration esterification of the carboxyl residue in the intermediate with the lactone-type sophorolipid, and the reaction temperature is controlled to rise less than 5 ° C. The esterification reaction is considered to be completed if the acid value does not change within half an hour. The product is reddish brown and has an acid value of 15 mg·KOH / g.

[0051] The resulting product exhibits excellent rust and corrosion resistance on various metals and low electrical conductivity.

[0052] Example 6.

[0053] Step (1), lactone-type sophorolipids and maleic anhydride are placed in an experimental apparatus equipped with a stirrer, a thermometer, a water separator and a condenser at a molar ratio of 1.70: 1. The experimental apparatus is inerted as a whole three times, and finally an inert gas protection is introduced, the condenser is opened, and the anhydride ring-opening reaction time is 2.2 hours at 105 ° C.

[0054] Step (2), the intermediate obtained in step (1) is further heated to 170 ° C. to carry out dehydration esterification of the carboxyl residue in the intermediate with the lactone-type sophorolipid, and the reaction temperature is controlled to rise less than 5 ° C. The esterification reaction is considered to be completed if the acid value does not change within half an hour. The product is reddish brown and has an acid value of 4 mg·KOH / g.

[0055] The resulting product exhibits general rust and corrosion resistance against various metals and low electrical conductivity.

[0056] Example 7.

[0057] Step (1), lactone-type sophorolipids and maleic anhydride are placed in an experimental apparatus equipped with a stirrer, a thermometer, a water separator and a condenser at a molar ratio of 1.80: 1. The experimental apparatus is inerted as a whole three times, and finally an inert gas protection is introduced, the condenser is opened, and the anhydride ring-opening reaction time is 2.6 hours at 98 ° C.

[0058] Step (2), the intermediate obtained in step (1) is further heated to 160 ° C for dehydration esterification of the carboxyl residue in the intermediate with the lactone-type sophorolipid, and the reaction temperature is controlled to rise less than 5 ° C. The esterification reaction is considered to be completed if the acid value does not change within half an hour. The product is reddish brown and has an acid value of 3 mg·KOH / g.

[0059] The resulting product exhibits general rust and corrosion resistance against various metals and low electrical conductivity.

[0060] Example 8.

[0061] Step (1), lactone-type sophorolipids and maleic anhydride are placed in an experimental apparatus equipped with a stirrer, a thermometer, a water separator and a condenser at a molar ratio of 1.90: 1. The experimental apparatus is inerted as a whole three times, and finally an inert gas protection is introduced, the condenser is opened, and the anhydride ring-opening reaction time is 1.2 hours at 115 ° C.

[0062] Step (2), the intermediate obtained in step (1) is further heated to 165 ° C. to carry out dehydration esterification of the carboxyl residue in the intermediate with the lactone-type sophorolipid, and the reaction temperature is controlled to rise less than 5 ° C. The esterification reaction is considered to be completed if the acid value does not change within half an hour. The product is reddish brown and has an acid value of 2 mg·KOH / g.

[0063] The resulting product exhibits general rust and corrosion resistance against various metals and low electrical conductivity.

[0064] Example 9.

[0065] Step (1), lactone-type sophorolipids and maleic anhydride are placed in an experimental apparatus equipped with a stirrer, a thermometer, a water separator and a condenser at a molar ratio of 2.00: 1. The experimental apparatus is inerted three times as a whole, and finally an inert gas protection is introduced, the condenser is opened, and the anhydride ring-opening reaction time is 2.5 hours at 100 ° C.

[0066] Step (2), the intermediate obtained in step (1) is further heated to 175 ° C. to carry out dehydration esterification of the carboxyl residue in the intermediate with the lactone-type sophorolipid, and the reaction temperature is controlled to rise less than 5 ° C. The esterification reaction is considered to be completed if the acid value does not change within half an hour. The product is reddish brown and has an acid value of 0.5 mg·KOH / g.

[0067] The resulting product exhibits general rust and corrosion resistance on a variety of metals and very low electrical conductivity.

[0068] Test example 1.

[0069] The samples prepared in Examples 1, 2, 3, 4, 5, 6, 7, 8, and 9 and the comparative sample tribasic acid (50%) and sebacic acid were prepared into a -35°C coolant according to the formula in Table 1, and neutralized with triethanolamine to a pH of 8.0 (25±0.2°C). 100 mL of the uniformly mixed coolant was then measured and its conductivity at 25±0.2°C was measured using a calibrated conductivity meter. The results are shown in Table 2.

[0070] Table 1

[0071]

[0072]

[0073] Table 2

[0074] sample Conductivity, μS / cm Recipe 1 92.5 Recipe 2 88.2 Recipe 3 83.8 Recipe 4 84.0 Recipe 5 83.0 Recipe 6 83.1 Recipe 7 81.3 Recipe 8 81.1 Recipe 9 80.0 Recipe 10 1307.4 Recipe 11 4001.2

[0075] As can be seen from Tables 1 and 2, the electrical conductivities of Examples 1, 2, 3, 4, 5, 6, 7, 8 and 9 are much smaller than those of tribasic acid and sebacic acid, and are less than 100 μS / cm.

[0076] Glassware corrosion tests were conducted using the coolants listed in Table 1. The test method was as follows: Each antifreeze sample was mixed with water to create a 33% antifreeze concentration (volume fraction) test solution. 99 mg of sodium sulfate, 110 mg of sodium chloride, and 92 mg of sodium bicarbonate were added per liter of test solution to prepare the corrosion solution. Test specimens were prepared from typical metals used in tram cooling systems (T2 copper, H70 brass, 20# steel, ZL101A cast aluminum, 3003 aluminum, 4043 aluminum, and 6063 aluminum). After polishing, cleaning, and weighing, they were assembled into a test bundle in the above order and placed in a test cup. 750 mL of tram coolant sample was then added to the corresponding cup. The cup was then placed on a heating device and heated for 336 h ± 2 h at a test temperature of 80 ± 2°C and an air flow rate of 100 ± 10 mL / min. The weight loss of each specimen was then measured. The mass change of the specimens was reported as the arithmetic mean of three replicate tests, accurate to the nearest 0.1 mg. The results are shown in Table 3 below.

[0077] Table 3

[0078]

[0079] As can be seen from the table above, when the coolant samples prepared in Examples 1, 2, 3, 4, and 5 are compared to a comparative coolant formulated with triprotic acid (50%) and sebacic acid, not only do they meet a conductivity of <100 μS / cm, but they also exhibit excellent rust and corrosion inhibition for typical metals used in tram cooling systems, with metal sheet weight loss within ±10 mg. In particular, the sample prepared in Example 3 exhibits significantly superior performance.

[0080] In summary, the present invention selects lactone-type sophorolipids as the initiator of the rust inhibitor for electric vehicle coolant in the molecular design, and performs an anhydride ring-opening reaction with maleic anhydride, and then performs an esterification and dehydration reaction on the reaction intermediate. The obtained polymaleated lactone-type sophorolipids have extremely low electrical conductivity and better rust and corrosion inhibition properties for various metals on the basis of the original rust inhibitor.

[0081] At the same time, the main raw materials of the present invention are glycolipid organisms, which have excellent biodegradability and low toxicity, and the preparation method is simple, easy to operate, and environmentally friendly; at the same time, the preparation method is carried out under normal pressure and has low requirements on equipment production conditions.

[0082] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A polymaleated lactone-type sophorolipid rust inhibitor for electric vehicle coolant, characterized in that The polymaleated lactone-type sophorolipid is prepared by a lactone-type sophorolipid, and the lactone-type sophorolipid includes the following general formula as shown in the chemical structural formula I: Wherein, R1 is a C1-C18 linear or branched saturated or unsaturated hydrocarbon group; R2 is a C2-C18 linear or branched saturated or unsaturated hydrocarbon group; The reaction process is shown in reaction equation II, wherein lactone-type sophorolipid and maleic anhydride are esterified and dehydrated at a high temperature of 90°C to 200°C to obtain polymaleated lactone-type sophorolipid; Polymaleated lactone-type sophorolipids+H2O Ⅱ.

2. The polymaleated lactone-type sophorolipid rust inhibitor for electric vehicle coolant according to claim 1, characterized in that The R1 is a C1-C3 straight-chain or branched saturated or unsaturated hydrocarbon group; R2 is a C10-C16 straight-chain or branched saturated or unsaturated hydrocarbon group.

3. A method for preparing a polymaleated lactone-type sophorolipid rust inhibitor for electric vehicle coolant according to claim 1, characterized in that First, a lactone-type sophorolipid and maleic anhydride are subjected to an anhydride ring-opening reaction, and then esterification and dehydration are performed under high temperature conditions to obtain a polymaleated lactone-type sophorolipid, comprising the following steps: Step (1), anhydride ring-opening reaction: adding lactone-type sophorolipid and maleic anhydride into a reactor, and carrying out an anhydride ring-opening reaction at 90°C to 120°C to obtain an intermediate; Step (2), esterification reaction; the intermediate obtained in step (1) is further heated to 140°C to 200°C to carry out dehydration esterification of the carboxyl residue in the intermediate with the lactone-type sophorolipid to obtain a polymaleated lactone-type sophorolipid.

4. The method for preparing the polymaleated lactone-type sophorolipid rust inhibitor for electric vehicle coolant according to claim 3, characterized in that Step (1), the lactone type sophorolipid and maleic anhydride are placed in a molar ratio of (1.00-2.00): 1 in an experimental apparatus equipped with a stirrer, a thermometer, a water separator and a condenser. The lactone type sophorolipid and maleic anhydride are placed in a reactor, the experimental apparatus is inerted as a whole 3 times, and finally an inert gas protection is introduced, the condenser is opened, and the anhydride ring-opening reaction is carried out at 90 ° C to 120 ° C.

5. The method for preparing the polymaleated lactone-type sophorolipid rust inhibitor for electric vehicle coolant according to claim 4, characterized in that The anhydride ring-opening reaction time is 1 to 3 hours.

6. The method for preparing the polymaleated lactone-type sophorolipid rust inhibitor for electric vehicle coolant according to claim 5, characterized in that The molar ratio of the lactone-type sophorolipid and maleic anhydride is (1.00-1.50):

1.

7. The method for preparing the polymaleated lactone-type sophorolipid rust inhibitor for electric vehicle coolant according to claim 4, characterized in that The inert gas is any one of nitrogen and argon.

8. The method for preparing the polymaleated lactone-type sophorolipid rust inhibitor for electric vehicle coolant according to claim 3, characterized in that In step (2), dehydration esterification, the reaction temperature is controlled to rise less than 5°C, and the esterification reaction is considered to be complete when the acid value does not change within half an hour.

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