KR101305076B1 - Manufacture method of extreme-pressure additive for lubricant using sulfur - Google Patents

Abstract

The present invention relates to a method for producing an extreme pressure additive for lubricating oil in which a fatty acid ester produced by reacting a fatty acid with an alcohol is reacted with sulfur to improve extreme pressure and lubricity.
According to the present invention, a fatty acid ester production process of producing fatty acid esters by reacting fatty oil with alcohol in the presence of a catalyst; It provides a method of producing a polar pressure additive for lubricating oil using a sulfur comprising a; and a sulfur-based extreme pressure additive generating step of reacting by adding sulfur to the fatty acid ester produced in the fatty acid ester production step to produce a sulfur-based extreme pressure additive.

Description

MANUFACTURE METHOD OF EXTREME-PRESSURE ADDITIVE FOR LUBRICANT USING SULFUR}

The present invention relates to a method for producing an extreme pressure additive for lubricating oil using sulfur. More specifically, the present invention relates to a method for producing an extreme pressure additive for lubricating oil in which fatty acid esters formed by reacting fatty acids with alcohols are reacted with sulfur to improve extreme pressure and lubricity.

Conventionally, lubricating oil is used to smoothly operate an internal combustion engine, a drive system such as an automatic transmission, a shock absorber, and a power steering, but since the lubricating performance is insufficient under high power and high load, the lubricating surface is friction and wear and eventually It is known to cause baking. Therefore, the lubricating oil which mix | blended extreme pressure additives, an antiwear agent, etc. is used.

However, the conventional extreme pressure additives were not sufficiently satisfactory, such as not exhibiting sufficient bake-preventing effect by interaction with other additives, corroding metals, or reducing wear resistance.

In addition, metal processing oils used in metal processing, such as cutting, grinding or plastic working, are manufactured by mixing oils, fatty acid esters, fatty acids such as alcohols or extreme pressure additives with mineral oils or synthetic hydrocarbon oils to improve workability. Is being done.

However, a new process oil is desired for such a metal processing oil which can further improve workability from the viewpoint of productivity improvement or energy saving. At the same time, chlorine-based extreme pressure additives, which have been widely used as extreme pressure additives in the past, tend to limit their use because they cause deterioration of the working environment, such as causing skin diseases on the human body or rust on the target metal.

As metal working oils in response to the above-mentioned demands, commercially available emulsions are obtained by adding sulfided olefins containing active sulfur and overbased sulfonates to base oils. The commercially available metalworking oil has good weldability and has the ability to prevent abnormal wear (for example, defects) of the tool and tearing of the processing surface. However, in a process in which friction with a relatively low load is repeated, the wear and tear of the tool by the active sulfur progresses, and the period until the replacement or regrinding of the tool is shortened, which often hampered the production efficiency. On the contrary, in the case of metal processing where abnormal abrasion is not a problem from the beginning, the production efficiency is often lowered.

Next, the working oil is a power transmission fluid used for operation such as power transmission, force control, and damping in a hydraulic system such as a hydraulic device or a device, and also performs a lubrication function of the sliding portion.

In these hydraulic fluids, in particular, it is essential performance to be excellent in load-preventing resistance and wear resistance. Therefore, the above-described performance is provided by incorporating extreme pressure additives, abrasion inhibitors, and the like into base oils such as mineral oil and synthetic oil. However, the conventional extreme pressure additives were not sufficiently satisfactory, even if the load-preventing effect was sufficient, such as insufficient wear resistance or corrosion corrosion.

In addition, gear oils, especially automotive gear oils, are rapidly increasing wear resistance and oxidative stability due to severe driving conditions such as long-distance transportation due to recent increase in load or development of a high-speed road network, extension of gang oil intervals, and the like. Became.

Until now, lubricating oil base oils mainly contained sulfide oils, sulfide olefins, phosphoric acid or thiophosphoric acid compounds, and extreme pressure additives such as zinc dithiophosphate or anti-wear additives, but they have high wear resistance, oxidation stability, and abrasion coefficient ratio (low speed / high speed). More reduction is needed.

As extreme pressure additives of conventional lubricating oils, sulfur-based extreme pressure additives have been mainly used. This sulfur-based extreme pressure additive has sulfur atoms in a molecule and dissolves or uniformly disperses in base oil to exert an extreme pressure effect. For example, sulfurized oils, sulfurized fatty acids, sulfided esters, polysulfides, sulfided olefins and thiocarbamates And thioterpenes, dialkylthiodipropionates and the like are known. However, these sulfur-based extreme pressure additives were not necessarily satisfactory because they had problems such as corrosion of the metal, interaction with other additives, or insufficient fire-preventing effect, or insufficient wear resistance.

The present invention has been made to solve the above problems, and has a load resistance and wear resistance superior to the conventional extreme pressure additives, as well as the extreme pressure additive for lubricants using sulfur used as a lubricant for low corrosion resistance to nonferrous metals The purpose is to provide a manufacturing method.

According to the present invention, a fatty acid ester production process of producing fatty acid esters by reacting fatty oil with alcohol in the presence of a catalyst; It provides a method of producing a polar pressure additive for lubricating oil using a sulfur comprising a; and a sulfur-based extreme pressure additive generating step of reacting by adding sulfur to the fatty acid ester produced in the fatty acid ester production step to produce a sulfur-based extreme pressure additive.

On the other hand, the fatty oil is characterized in that one selected from soybean oil, palm oil, pork and oleic acid.

On the other hand, the fatty acid ester is produced by reacting the fatty oil and alcohol in the presence of a catalyst for a reaction time of 18 hours to 24 hours, while cooling the alcohol that is evaporated while reacting while maintaining the temperature above the boiling point of the alcohol The alcohol is continuously reacted with the unreacted fatty oil to produce fatty acid esters.

On the other hand, the fatty acid ester produced in the fatty acid ester production process is characterized in that the state is removed from the water.

On the other hand, the sulfur-based extreme pressure additive production process is a water removal process for removing the water remaining in the fatty acid ester; And adding sulfur to the fatty acid ester from which water has been removed, and reacting the sulfur with the fatty acid ester while gradually raising the temperature until the temperature reaches a constant temperature, thereby producing a sulfur-based extreme pressure additive.

On the other hand, the sulfur-based extreme pressure additive production process is characterized in that for reacting by adding 1 to 8 parts by weight of the sulfur with respect to 100 parts by weight of the fatty acid ester.

The present invention has the effect of improving the extreme pressure and lubricity by reacting the fatty acid ester produced by reacting the fatty acid and alcohol with sulfur.

In addition, the extreme pressure additive according to the present invention does not smell as compared to the existing extreme pressure additives, and has an effect of excellent polar pressure resistance and wear resistance.

In addition, the extreme pressure additive according to the present invention can also reduce the cost and also low cost, it is possible to replace the existing imports there is an effect that can contribute to domestic domestic power generation.

1 is a graph showing the results of the Timken test when the load of 1kg according to an embodiment of the present invention.
Figure 2 is a graph showing the results of the Timken test when the load of 3kg according to an embodiment of the present invention.
Figure 3 is a graph showing the results of the Timken test when the load of 5kg according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

The method for preparing an extreme pressure additive according to the present invention comprises the following steps: i) a fatty acid ester production process for producing a fatty acid ester by reacting fatty oil with alcohol in the presence of a catalyst, and ii) adding sulfur to the fatty acid ester produced in the fatty acid ester production process. Reacting to produce a sulfur-based extreme pressure additive.

Here, the fatty oil is preferably one selected from soybean oil, palm oil, pork oil and oleic acid. This will be explained through the following examples.

Here, looking at the production process of fatty acid ester is as follows.

Fatty acid + alcohol → fatty acid ester + water

(RCOOH + ROH → RO-CO-R '+ H ₂ O)

Fatty oil refers to the inclusion of fatty acids and glycerol, and therefore fatty acids refers to fatty oil minus glycerol. Therefore, since fatty oil contains fatty acids, it reacts with alcohol as fatty acid as above, and after the reaction, fatty acid ester and water are produced, and glycerol with low specific gravity remains in the lower part of fatty acid ester. In brief, the fatty acid is a carboxylic acid of a hydrocarbon chain having one carboxyl group (-COOH), and refers to a monovalent carboxylic acid, and a fatty acid is a double or triplet with a saturated fatty acid having a carbon chain saturated (single bond). It consists of unsaturated fatty acids in a bound form.

The fatty acid ester production process reacts the fatty oil with alcohol in the presence of a catalyst for 18 to 24 hours, but cools the alcohol to be evaporated while reacting while maintaining the temperature above the boiling point of the alcohol. It is preferred to continuously react with unreacted fatty oil to produce fatty acid esters. In this case, alcohol is used as general methanol, and the reaction is continuously performed while returning methanol through the reflux cooler, thereby reducing the raw material cost and improving the reaction rate. Fatty acid ester produced through the fatty acid ester production process can be confirmed through a tester of NMR or GC.

After repeating the test a number of times in the test process, the reaction time was at least 18 hours to obtain a complete fatty acid ester.

On the other hand, the fatty acid ester produced in the fatty acid ester production process is preferably to remove the water present in the interior. This is to increase the reactivity with sulfur in the future.

In addition, due to the nature of the fatty acid it is difficult to react with the methanol in an exact amount, the excess methanol after the reaction is added to recover the methanol and return it while reacting with the fatty acid again to produce a fatty acid ester.

The sulfur-based extreme pressure additive production process is a water removal process for removing the water remaining inside the fatty acid ester, sulfur is added to the fatty acid ester from the water is removed step by step to increase the temperature until a certain temperature is reached And reacting with sulfur to produce sulfur-based extreme pressure additives. This is illustrated in the formula below. Sulfur here means yellow sulfur, also called sulfur.

The reason why the moisture removal process is included in the process of producing the sulfur-based extreme pressure additive is that the reaction with sulfur is not performed well in case there is a small amount of water, and thus the water is removed once again in consideration of the reactivity with sulfur.

In addition, the temperature is raised step by step, because if the temperature is raised rapidly, the color of the reactants may turn black or the precipitation of sulfur may not occur. This is because sulfur may be carbonized and remain in a free state or odor may be severe due to carbonized sulfur.

If the reaction proceeds normally, the color of the initial reactant can be seen to change from yellow to brown.

On the other hand, the sulfur-based extreme pressure additive production process is preferably reacted by adding 1 to 8 parts by weight of sulfur with respect to 100 parts by weight of the fatty acid ester. The reason is that if the sulfur content is too low, the reactivity may be lowered. If the sulfur content is too high, sulfur may remain after the reaction.

The present invention is described in more detail with reference to the following Examples, but the present invention is not limited to these Examples.

Soybean oil was selected from fatty oils. General physical properties of the soybean oil are shown in Table 1 below. It is noted that alcohol used representative methanol, and citric acid was used as a catalyst. The embodiment will be divided into two processes, namely, fatty acid ester production and sulfur-based extreme pressure additive production.

sample
division Soybean oil Remarks Acid value 1.8 Peroxide value 3.1 Iodine value 135.8 Moisture (%) 0.046

First of all, i) 200 liters of soybean oil, 1200 ml of methanol, and 1.0 g of citric acid as catalyst were installed in a round flask for fatty acid ester, and a reflux cooler was installed. Proceed with the reaction. ii) Methanol has a boiling point of about 64.7 ℃ and the reaction temperature of 70 ℃ methanol continues to evaporate, the return of the liquid methanol through the reflux cooler to continue the reaction. iii) After the reaction is finished within 18 to 24 hours, the reaction is finally confirmed, and fatty acid esters are produced. At this time, the upper layer is separated into an ester layer and a lower layer is separated into glycerol by specific gravity. After cooling, the solution is transferred to a separatory funnel, and only the upper ester layer is recovered. The ester solution, which has been acidified with citric acid added as a catalyst, is neutralized with caustic soda (NaOH) or potassium hydroxide (KOH). iv) After neutralization, water generated during the fatty acid esterification process is removed by heating to about 120 ° C. v) The final fatty acid esters are filled with argon or nitrogen gas to prevent penetration of moisture in the air, and then sealed and stored to prevent them from being altered.The lower glycerol is used separately and the remaining methanol is recovered. Do it. At this time, it can be confirmed whether the fatty acid ester is properly reacted through a tester of NMR or GC.

Then, as a sulfur-based extreme pressure additive production process i) the fatty acid ester produced in advance in the reactor (500ml four-necked flask), the temperature is raised to 120 ℃ dehydration (regardless of the amount of water to be removed in the future it is well reacted with sulfur. In particular, stirring at 600 rpm to maintain this temperature for 30 minutes almost eliminates moisture). ii) After dehydration, take 1g to 8g of sulfur, put it in a reactor, and keep it warmed up. iii) When the temperature reaches 150 ° C, the temperature is increased by 1 ° C for about 5 minutes. (If the temperature is raised rapidly, the color of the reactant suddenly turns black or the sulfur does not melt, and some of the sulfur is carbonized and remains free. Or strong odor with sulfurized carbon). iv) When the temperature reaches 170 ° C., the reaction is terminated to produce a sulfur-based extreme pressure additive. In this case, the final reaction time was about 2 hours, and when the reaction was normally performed, it can be seen that the color of the initial reactant changed from yellow to brown, and there was no residue of sulfur in the reactor.

Therefore, fatty acid esters were produced using soybean oil, methanol as fatty oil, and hydrochloric acid as catalyst, and sulfur was added to finally produce sulfur-based extreme pressure additive.

Palm oil was selected from fatty oils. General physical properties of the palm oil are shown in Table 2 below. It is noted that alcohol used representative methanol, and citric acid was used as a catalyst. Example 2 is the same as the production process of the final sulfur-based extreme pressure additive except that palm oil instead of soybean oil of Example 1 will be omitted here.

sample
division Palm oil Remarks Acid value 0.048 Peroxide value 0.21 Iodine value 51.2 Moisture (%) 0.060

Among oils, lard oil was selected and used. General physical properties of the larch is as shown in Table 3 below. It is noted that alcohol used representative methanol, and citric acid was used as a catalyst. Example 3 is the same as the production process of the final sulfur-based extreme pressure additive except for using larch instead of soybean oil of Example 1 will be omitted here.

sample
division Lard oil Remarks Acid value 0.04 Peroxide value 0.15 Iodine value 65.1 Moisture (%) 0.048

Oleic acid was selected from fatty oils. General physical properties of the oleic acid are shown in Table 4 below. It is noted that alcohol used representative methanol, and citric acid was used as a catalyst. In Example 4, except that oleic acid is used instead of soybean oil of Example 1, the process of producing the final sulfur-based extreme pressure additive is the same, and thus will be omitted here.

sample
division Oleic acid Remarks Acid value max 7.0 Swordsman 185 Pour Point (℃) -15.0 Flash point (℃) 180

Comparative Example 1

A commercially available sulfur-based extreme pressure agent was used.

Finally, for Examples 1 to 4 and Comparative Example 1, i) smell test, ii) dynamic activity test, iii) Four ball test, and iv) Timken test were performed to test the performance of the sulfur-based extreme pressure additive. Here, the odor test and the dynamic activity test are performance tests of the sulfur-based extreme pressure additive itself, and the flash point test, the Four ball test, and the Timken test represent the performance tests when the base oil is mixed with the sulfur-based extreme pressure additive.

Table 5 shows odor test and dynamic activity test, Table 6 shows Four ball test, Table 7 shows 1kg load, Table 8 shows 3kg load and Table 9 shows 5kg Timken Indicates a test. And the results for Tables 7 to 9 are shown in FIGS.

The upper part of Table 5 shows the odors of all healthy men and two women in order to identify the odors of all products reacted with fatty acid esters and sulfur. . As a result, as shown in [Table 5], good results were obtained in soybean oil (Example 1) and pig paper (Example 3) when compared with commercial sulfur-based extreme pressure additives (Comparative Example 1).

The lower part of Table 5 shows the results of measuring the copper activity of the product using the KS M 2018 copper corrosion test method to confirm the copper activity. As a result, as shown in [Table 5], fatty acid esters synthesized with lard (Example 3) showed that the copper activity was not shown even when the sulfur content was increased, and the remaining fatty acid esters were sulfur content. It could be confirmed that the higher the activity, the higher the activity.

As a result of evaluating the physical properties of the odor and the copper activity through Table 5, it was found that the fatty acid ester (Example 3) which synthesized the ester of lactic acid was the best compared to the commercial sulfur-based extreme pressure additive (Comparative Example 1). Could.

Four ball test is a method of judging the extreme pressure and abrasion resistance of lubricating oil. As a criterion for ASTM, seizure load causes excessive scuffing of metal surface for the first time when load is gradually increased from mild area. It is mainly affected by the viscosity of base oil and anti-wear additives. Welding load is welded on both surfaces by direct contact between metal surface and lubrication film is completely destroyed in very high load area. This occurs load point is mainly affected by extreme pressure additives.

[Table 6] shows the results of the four ball test, and the seizzure load shows 160kg of all sulfur-based extreme pressure additives (Comparative Example 1), Example 3 (donji), and the samples without extreme pressure additives. The welding load is excellent in the extreme pressure of the sample to which Example 3 according to the present invention is added compared to the sample to which the extreme pressure additive is not added and the commercial sulfur-based extreme pressure additive (Comparative Example 1). And it was found.

In addition, the scars of the samples containing Example 3 according to the present invention were lower than those of the samples containing the extreme pressure-free sample and the commercial sulfur-based extreme pressure additive (Comparative Example 1). It was found to reduce damage.

Timken test is a method of judging the extreme pressure of lubricating oil. As a criterion for ASTM, the OK value refers to the maximum load that causes constant damage to the rotating cup and the fixed block, that is, does not destroy the lubricating film. If exceeded, extreme wear occurs, causing rough surface at the edge of friction surface by plastic flow of friction surface and cold welding of wear particles.

[Table 7] to [Table 9] and Figures 1 to 3 are the results of the Timken test, it is a value shown by measuring the resistance value generated by the content of each extreme pressure additive at a load of 1kg, 3kg, 5kg. As a result, the resistance value decreases as the content of the extreme pressure additive increases, and the resistance value significantly decreases from 5% of the extreme pressure additive, and the resistance value does not decrease much even if the content of the extreme pressure additive increases from 8%. appear.

Therefore, as the content of the additives of Examples 1, 3, 4 and Comparative Example 1 increases, the resistance value generally decreases, but the resistance value does not significantly decrease from the content of any one or more additives. Comparing Example 1 with the rest of the examples, it can be seen that a similar level of resistance is maintained.

In summary, the extreme pressure additive of the present invention, in which a fatty acid ester (soybean oil, lard, palm oil, oleic acid) which can be used as an extreme pressure additive in a non-aqueous cutting oil or a plasticizer, is reacted with sulfur, the sulfur-based extreme pressure additive is added. It was found that the extreme pressure was much higher than that of the non-product, and the extreme pressure was superior to the conventional sulfur-based extreme pressure additive (Comparative Example 1).

In addition, since the extreme pressure additive according to the present invention is superior to the domestic extreme pressure additive used as an existing sulfur-based extreme pressure additive, it is judged that it can extend the life of the emulsion due to its excellent workability when applied to cutting oil and plastic processing, and commercial sulfur-based extreme pressure additive. Compared with (Comparative Example 1), it was found that not only the pressure resistance was excellent but also the price was very low, thus reducing the cost.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. Therefore, the embodiments disclosed in the present specification are intended to illustrate rather than limit the present invention, and the scope and spirit of the present invention are not limited by these embodiments. The scope of the present invention should be construed according to the following claims, and all the techniques within the scope of the present invention should be construed as being included in the scope of the present invention.

Claims (6)

delete delete delete delete Fatty acid ester production process of producing fatty acid ester by reacting fatty oil with alcohol in the presence of a catalyst; And
Sulfur is added to the fatty acid ester produced during the fatty acid ester production to react to produce a sulfur-based extreme pressure additive, and a water removal process for removing water remaining in the fatty acid ester and sulfur is added to the fatty acid ester from which the water is removed. Then, the sulfur-based extreme pressure additive generating process comprising the step of reacting sulfur with fatty acid ester while producing a sulfur-based extreme pressure additive while gradually raising the temperature until a constant temperature is reached;
The fatty oil is one selected from soybean oil, palm oil, pork oil and oleic acid, and the fatty acid ester production process reacts fatty oil and alcohol in the presence of a catalyst for a reaction time of 18 hours to 24 hours, while maintaining a temperature above the boiling point of alcohol. Cooling the alcohol to be evaporated while reacting at and continuously reacting the cooled alcohol with the unreacted fatty oil to produce a fatty acid ester, the fatty acid ester produced in the fatty acid ester production process to remove the water present therein Method for producing an extreme pressure additive for lubricating oil using sulfur, characterized in that.
6. The method of claim 5,
The sulfur-based extreme pressure additive production process of the sulfur-based extreme pressure additive for the lubricant using sulfur, characterized in that for reacting by adding 1 to 8 parts by weight of sulfur with respect to 100 parts by weight of the fatty acid ester.

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