Low-sediment overbased magnesium detergent, preparation method thereof and lubricating oil composition

Abstract

The invention provides a low-sediment overbased magnesium detergent, a preparation method thereof and a lubricating oil composition. The preparation method comprises the following steps: reacting short-chain carboxylic acid, C8-C10 fatty acid and organic amine to obtain an accelerant; mineral oil, solvent oil, a first part of low-carbon alcohol and alkyl salicylic acid are subjected to a first heating reaction, and then a first part of magnesium oxide is added for a second heating reaction; adding an accelerant and a second part of magnesium oxide into a reaction product, then carrying out carbonation, and carrying out a post-treatment step after the reaction is finished, so as to obtain the overbased magnesium detergent, the molar ratio of the short-chain carboxylic acid to the C8-C10 fatty acid to the organic amine is (1-1.5): (0.5-1): 1. The overbased magnesium detergent disclosed by the invention is relatively high in base number, excellent in colloidal stability, extremely low in coarse sediment volume, less in generated waste residue and high in magnesium oxide utilization rate.

Description

TECHNICAL FIELD

[0001] The present application relates to a low-deposit overbased magnesium detergent, a preparation method thereof and a lubricating oil composition, and belongs to the technical field of detergents. BACKGROUND

[0002] With the continuous progress of internal combustion engine technology, turbocharged engines not only have high fuel economy, but also can reduce exhaust emissions to a certain extent. However, such engines are prone to low-speed pre-ignition (LSPI) phenomenon under low-speed and high-load working conditions. There is a direct correlation between calcium salt detergent in lubricating oil and LSPI phenomenon, that is, the higher the calcium content, the more frequent the LSPI phenomenon. However, magnesium salt detergent usually does not cause LSPI phenomenon, because under the same base number conditions, magnesium salt produces less ash. Therefore, reducing the amount of calcium salt detergent in lubricating oil or using magnesium salt detergent can effectively control or reduce the occurrence of LSPI phenomenon.

[0003] In the synthesis of high-base magnesium detergent, the activity of magnesium oxide is crucial. It is difficult to produce high-base magnesium sulfonate of the same specification using light-burned, hard-burned or heavy-burned grades of magnesium oxide or mixtures of different grades. To this end, CN108219896 solves the above problem by using a promoter system containing polyisobutylene succinic anhydride with a specified number average molecular weight as a first promoter and salicylic acid as a second promoter. The invention has strong universality and can adapt to magnesium oxide from different sources. CN116478747 discloses a magnesium salicylate detergent with a base number greater than 300 mgKOH / g, which solves the problem of difficulty in absorbing carbon dioxide during high-alkalinity process caused by changes in raw material synthesis process and composition, thereby causing low yield, low base number and high turbidity. Although the alkyl magnesium salicylate product prepared by the process has excellent high-temperature detergency and good colloidal stability, the process has the defect of low raw material utilization rate.

[0004] Lubricating oil detergent is mainly composed of two parts of metal soap and basic carbonate. Metal soap has strong cleaning ability and can effectively remove internal carbon deposits of the engine. Basic carbonate can neutralize acidic substances generated by lubricating oil at high temperatures in time. Metal detergent plays an important role in keeping engine parts clean, reducing wear and tear, and prolonging engine service life.

[0005] Because the metallic properties of magnesium are weaker than those of calcium, the preparation of magnesium salt detergent is more difficult than that of calcium salt detergent. In addition, the solubility of magnesium hydroxide and magnesium carbonate in water is close, which not only makes it difficult for magnesium hydroxide to be carbonated to form magnesium carbonate, but also makes it easy for a large amount of magnesium hydroxide to aggregate and form a precipitate under the association of hydrogen bonds, which cannot enter the micelle as an effective base reserve. The above problems result in low raw material utilization rate, which not only increases the production cost, but also increases the cost of solid waste treatment.

[0006] In view of this, it is of great significance to develop a low-sediment overbased magnesium detergent with high raw material utilization rate, low solid waste generation, low production cost and stable product quality. SUMMARY

[0007] To solve the above technical problems, the purpose of the present application is to provide a low-sediment overbased magnesium detergent, its preparation method and a lubricating oil composition. The magnesium detergent of the present application has a low volume of coarse sediment and a high base number, and has excellent colloidal stability.

[0008] To achieve the above-mentioned purpose, in a first aspect, the present application provides a preparation method of a low-sediment overbased magnesium detergent, comprising the following steps:

[0009] reacting a short-chain carboxylic acid, a C8-C 10 fatty acid, and an organic amine to obtain a promoter;

[0010] performing a first heating reaction on mineral oil, solvent oil, a first low-carbon alcohol, and alkyl salicylic acid, and then adding a first portion of magnesium oxide to perform a second heating reaction;

[0011] adding the promoter and a second portion of magnesium oxide to the product of the above reaction, and then performing carbonation, and after the reaction is completed, performing a post-treatment step to obtain an overbased magnesium detergent;

[0012] wherein the molar ratio of the short-chain carboxylic acid, the C8-C 10 fatty acid, and the organic amine is (1-1.5):(0.5-1):1.

[0013] According to the specific embodiments of the present application, preferably, the amount of solvent oil added is 250-350 parts by weight based on 100 parts by weight of mineral oil, the amount of the first low-carbon alcohol added is 5-15 parts, the amount of alkyl salicylic acid added is 100 parts, the amount of the first portion of magnesium oxide added is 10-15 parts, the amount of the promoter added is 5-8 parts, and the total amount of the first portion of magnesium oxide and the second portion of magnesium oxide added is 25-32 parts.

[0014] In the present application, the first heating reaction is performed on mineral oil, solvent oil, a first low-carbon alcohol, and alkyl salicylic acid, and then a first portion of magnesium oxide is added to perform a second heating reaction. The addition of magnesium oxide after the second heating reaction can reduce the viscosity of the product.

[0015] According to the specific embodiments of the present application, preferably, the total amount of the first portion of magnesium oxide and the second portion of magnesium oxide added is 25-32 parts by weight based on 100 parts by weight of mineral oil.

[0016] According to the specific embodiments of the present application, preferably, the short-chain carboxylic acid is selected from formic acid and / or acetic acid. If a long-chain carboxylic acid is used, it cannot play a promoting role, resulting in an increase in coarse sediment.

[0017] According to the embodiment of the present application, preferably, the C8-C 10 fatty acid is selected from one or more than two combinations of n-octanoic acid, iso-octanoic acid, iso-nonyl acid, neodecanoic acid, more preferably, the C8-C 10 fatty acid is selected from iso-octanoic acid and / or neodecanoic acid. If other carbon chain fatty acids are used, the promotion effect cannot be achieved, resulting in the increase of coarse precipitates.

[0018] According to the embodiment of the present application, preferably, the organic amine is selected from one or more than two combinations of ethylenediamine, ethanolamine, diethanolamine.

[0019] According to the embodiment of the present application, preferably, the short chain carboxylic acid, the C8-C 10 fatty acid, and the organic amine are reacted for 10-30 min, more preferably for 0.5 h, and the reaction temperature is room temperature. The present application uses the short chain carboxylic acid, the C8-C 10 fatty acid, and the organic amine as raw materials to prepare the promoter, which can promote the absorption of carbon dioxide gas and assist the migration of magnesium carbonate colloidal particles from the organic phase to the inorganic phase to form stable colloids, ensuring that the magnesium detergent has excellent base value and colloidal stability, thereby improving the conversion rate of magnesium oxide and the yield of magnesium detergent.

[0020] According to the embodiment of the present application, preferably, the mineral oil is selected from one or more than two combinations of 100N, 150SN, 150N, 500N, 500SN, more preferably 150SN and / or 150N.

[0021] According to the embodiment of the present application, preferably, the solvent oil is an alkane solvent oil, more preferably, the solvent oil is selected from one or more than two combinations of D30, D40, dimethylbenzene, further preferably dimethylbenzene.

[0022] According to the embodiment of the present application, preferably, the first low-carbon alcohol is a C1-C4 low-carbon alcohol, more preferably, the first low-carbon alcohol is selected from one or more than two combinations of methanol, ethanol, propanol, butanol, further preferably methanol.

[0023] According to the embodiment of the present application, preferably, the alkyl salicylic acid is a C 14 -C 30 alkyl salicylic acid; more preferably, the alkyl salicylic acid includes C 14 -C 18 alkyl salicylic acid and C 24 -C 28 alkyl salicylic acid, wherein C 14 -C 18Alkyl salicylic acid and C 24 -C 28 The mass ratio of alkyl salicylic acid to C is 1:1; more preferably, the C 14 -C 18 The alkyl salicylic acid comprises a mixture of tetradecyl salicylic acid, hexadecyl salicylic acid, and octadecyl salicylic acid, wherein C 24 -C 28 Alkyl salicylic acids include mixtures of tetracosyl salicylic acid, hexacosyl salicylic acid, and octacosyl salicylic acid. The structures of alkyl salicylic acids are shown below, where R is a saturated hydrocarbon group with one of 14, 16, 18, 24, 26, or 28 carbon atoms.

[0024] .

[0025] According to a specific embodiment of the present invention, preferably, the temperature of the first heating reaction is 40-50 °C and the time is 1-2 h.

[0026] According to a specific embodiment of the present invention, preferably, the temperature of the second heating reaction is 50-60 °C and the time is 1-2 h.

[0027] According to a specific embodiment of the present invention, preferably, the promoter and a second part of magnesium oxide are added to the product of the above reaction, and then carbon dioxide is introduced while a mixture of a second low-carbon alcohol and water is added dropwise over 1-3 hours. More preferably, the amount of carbon dioxide introduced is 30-50 parts per 100 parts by weight of mineral oil; even more preferably, the time for introducing carbon dioxide is 2-4 hours.

[0028] According to a specific embodiment of the present invention, preferably, the second part of the low-carbon alcohol is selected from one or more combinations of methanol, ethanol, propanol, and butanol, more preferably methanol. Further, based on 100 parts by weight of mineral oil, the amount of the second part of the low-carbon alcohol added is 10-20 parts, and the amount of water added is 15-25 parts. In this invention, water is not added during the neutralization stage, but rather a mixture of the second part of the low-carbon alcohol and water is slowly added dropwise during the carbonation reaction stage to control the rate of magnesium hydroxide formation and effectively reduce the formation of precipitates. Otherwise, a large amount of magnesium hydroxide would form. Since the solubility product of magnesium hydroxide is less than that of magnesium carbonate, magnesium hydroxide cannot be converted into magnesium carbonate in time, ultimately associating to form a precipitate.

[0029] According to a specific embodiment of the present invention, preferably, based on 100 parts by weight of mineral oil, the total addition amount of the first part of low-carbon alcohol and the second part of low-carbon alcohol is 20-30 parts.

[0030] According to the specific embodiment of the present application, preferably, the step of post-treatment comprises: heating to 100-135℃, and then the steps of centrifugal separation and reduced pressure distillation. The step of post-treatment can be carried out according to the conventional purification method in the art, for example: heating the product obtained from the carbonation reaction to 100-135℃, removing alcohol, water and solvent oil (for example, xylene), removing residue by centrifugation or filtration, and then performing reduced pressure distillation (removing product solvent) to obtain the overbased magnesium detergent.

[0031] In the second aspect, the present application further provides the overbased magnesium detergent prepared by the preparation method.

[0032] In the third aspect, the present application further provides a lubricating oil composition prepared by the overbased magnesium detergent prepared by the preparation method or the overbased magnesium detergent.

[0033] Compared with the prior art, the present application has the following beneficial effects:

[0034] The method for preparing the overbased magnesium detergent of the present application comprises a neutralization reaction and a carbonation reaction. The promoter prepared by using short-chain carboxylic acid, C8-C 10 and organic amine as raw materials can promote the absorption of carbon dioxide gas, and at the same time, assist the migration of magnesium carbonate colloidal particles from the organic phase to the inorganic phase, so that the overbased magnesium detergent prepared has a higher base value, ensures the colloidal stability, has a low volume of coarse sediment, produces less waste residue, and has a high utilization rate of magnesium oxide. DETAILED DESCRIPTION

[0035] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present application, the technical solutions of the present application are described in detail as follows, but it should not be understood as a limitation on the implementable scope of the present application.

[0036] The C 14 -C 18 alkyl salicylic acid and C 24 -C 28 alkyl salicylic acid are prepared as follows:

[0037] (1) Preparation method of C 14 -C 18 alkyl salicylic acid:

[0038] Into a four-necked flask, 125 parts of salicylic acid, 60 parts of n-tetradecene, 88 parts of n-hexadecene, 50 parts of n-octadecene and 25 parts of methyl sulfonic acid are added, stirring and heating are started, all the materials are kept at 120℃ for 24h, cooled to 80℃ and 300 parts of D30 solvent oil are added, stirred uniformly, and then placed for 12h, the lower layer of methyl sulfonic acid is separated, and the upper layer of material is subjected to reduced pressure distillation to remove solvent, to obtain C 14 -C18 Alkyl salicylic acid.

[0039] (2) C 24 -C 28 Preparation method of alkyl salicylic acid:

[0040] 150 parts of salicylic acid, 165 parts of n-docosahexaene, 135 parts of n-docosahexaene, 80 parts of n-octacosene, and 56 parts of methanesulfonic acid were added to a four-necked flask. Stirring and heating were started, and all materials were kept at 135°C for 24 hours. The temperature was then lowered to 80°C, and 500 parts of D30 solvent oil were added. After stirring evenly, the mixture was allowed to stand for 12 hours. The lower layer of methanesulfonic acid was separated, and the upper layer was subjected to vacuum distillation to remove the solvent, yielding C. 24 -C 28 Alkyl salicylic acid.

[0041] Example 1

[0042] This embodiment provides a method for preparing an alkaline magnesium detergent, comprising the following steps:

[0043] Preparation of accelerator: Add 5g of formic acid and 7g of neodecanoic acid to a beaker, and slowly add 4.5g of ethylenediamine while stirring. Continue stirring for 0.5h to obtain the accelerator.

[0044] Neutralization reaction: In a flask, add 100 parts of 150SN, 250 parts of xylene, 5 parts of methanol (first batch), and 100 parts of alkyl salicylic acid sequentially (C). 14 -C 18 Alkyl salicylic acid and C 24 -C 28 (The mass ratio of alkyl salicylic acid is 1:1). Start stirring and heat to 50°C. After holding at this temperature for 1 hour, add 10 parts of the first part of magnesium oxide and hold at 50°C for 2 hours.

[0045] Carbonation reaction: Add 5 parts of the above-mentioned promoter and 15 parts of the second magnesium oxide to the product of the above reaction, and pass 30 parts of carbon dioxide through it within 2 hours. At the same time, add a mixture of the second part of methanol (15 parts) and pure water (15 parts) dropwise (control the dropwise addition time to 1 hour). After the gas is purged, raise the temperature to 120°C to remove methanol, water and part of xylene from the system. After centrifugation to remove residue and vacuum distillation, the crude product is used to obtain superalkaline magnesium detergent.

[0046] Example 2

[0047] This embodiment provides a method for preparing an alkaline magnesium detergent, comprising the following steps:

[0048] Preparation of accelerator: Add 6 g of formic acid and 10 g of isooctanoic acid to a beaker, and slowly add 6 g of ethanolamine while stirring. Continue stirring for 0.5 h to obtain the accelerator.

[0049] Neutralization reaction: In a flask, add 100 parts of 150SN, 280 parts of xylene, 12 parts of methanol (first batch), and 100 parts of alkyl salicylic acid sequentially (C). 14 -C 18 Alkyl salicylic acid and C 24 -C 28 (The mass ratio of alkyl salicylic acid is 1:1). Start stirring and heat to 40 °C. After holding at this temperature for 1 hour, add 12 parts of the first part of magnesium oxide and hold at 55 °C for 2 hours.

[0050] Carbonation reaction: Add 6 parts of the above-mentioned promoter and 16 parts of the second magnesium oxide to the product of the above reaction, and pass 40 parts of carbon dioxide through the system within 2.5 h, while simultaneously adding a mixture of the second part of methanol (10 parts) and pure water (19 parts) dropwise (controlling the dropwise addition time to 1.5 h). After the gas passage is completed, raise the temperature to 120 °C to remove methanol, water and part of xylene from the system. After centrifugation to remove residue and vacuum distillation, the crude product is used to obtain superalkaline magnesium detergent.

[0051] Example 3

[0052] This embodiment provides a method for preparing an alkaline magnesium detergent, comprising the following steps:

[0053] Preparation of accelerator: Add 8g of acetic acid and 12g of neodecanoic acid to a beaker, and slowly add 6g of ethylenediamine while stirring. Continue stirring for 0.5h to obtain the accelerator.

[0054] Neutralization reaction: In a flask, add 100 parts of 150SN, 300 parts of xylene, 15 parts of methanol (first batch), and 100 parts of alkyl salicylic acid sequentially (C). 14 -C 18 Alkyl salicylic acid and C 24 -C 28 (The mass ratio of alkyl salicylic acid is 1:1). Start stirring and heat to 45 °C. After holding at this temperature for 1 hour, add 10 parts of the first part of magnesium oxide and hold at 55 °C for 2 hours.

[0055] Carbonation reaction: Add 8 parts of the above-mentioned promoter and 20 parts of the second magnesium oxide to the product of the above reaction, and pass 45 parts of carbon dioxide through it within 3 hours. At the same time, add a mixture of the second part of methanol (10 parts) and pure water (23 parts) dropwise (control the dropwise addition time to 2 hours). After the gas is purged, raise the temperature to 120°C to remove methanol, water and part of xylene from the system. After centrifugation to remove residue and vacuum distillation, the crude product is used to obtain superalkaline magnesium detergent.

[0056] Example 4

[0057] This embodiment provides a method for preparing an alkaline magnesium detergent, comprising the following steps:

[0058] Preparation of accelerator: add acetic acid 4 g, neodecanoic acid 8 g into a beaker, slowly add 3.5 g ethanolamine under stirring, continue stirring for 0.5 h, and then the accelerator is obtained.

[0059] Neutralization reaction: add 150N 100 parts, xylene 350 parts, first portion of methanol 10 parts and alkyl salicylic acid 100 parts (C 14 -C 18 The mass ratio of alkyl salicylic acid to C 24 -C 28 The mass ratio of alkyl salicylic acid to C

[0060] Carbonation reaction: add the accelerator 8 parts, second portion of magnesium oxide 20 parts to the product of the above reaction, and pass 50 parts of carbon dioxide in 4 h, while dropping the mixture of second portion of methanol (20 parts) and pure water (25 parts) (control the dropping time for 2.5 h), after the end of the aeration, increase the temperature to 120 ℃ to remove methanol, water and part of xylene in the system, and the crude product is obtained after centrifugal slag removal and reduced pressure distillation, to obtain the overbased magnesium detergent.

[0061] Example 5

[0062] The embodiment provides a preparation method of an overbased magnesium detergent, comprising the following steps:

[0063] Preparation of accelerator: add acetic acid 4.3 g, isooctanoic acid 10.3 g into a beaker, slowly add 7.5 g diethanolamine under stirring, continue stirring for 0.5 h, and then the accelerator is obtained.

[0064] Neutralization reaction: add 150N 100 parts, xylene 320 parts, first portion of methanol 10 parts and alkyl salicylic acid 100 parts (C 14 -C 18 The mass ratio of alkyl salicylic acid to C 24 -C 28 The mass ratio of alkyl salicylic acid to C

[0065] Carbonation reaction: add the accelerator 7 parts, second portion of magnesium oxide 15 parts to the product of the above reaction, and pass 40 parts of carbon dioxide in 3.5 h, while dropping the mixture of second portion of methanol (17 parts) and pure water (22 parts) (control the dropping time for 2 h), after the end of the aeration, increase the temperature to 120 ℃ to remove methanol, water and part of xylene in the system, and the crude product is obtained after centrifugal slag removal and reduced pressure distillation, to obtain the overbased magnesium detergent.

[0066] Comparative example 1

[0067] The present comparative example provides a preparation method of a magnesium detergent, comprising the following steps:

[0068] Preparation of the accelerator: add formic acid 5 g into a beaker, slowly add ethylenediamine 4.5 g under stirring, and continue stirring for 0.5 h to obtain the accelerator.

[0069] Neutralization reaction: add 150SN 100 parts, xylene 300 parts, first methanol 5 parts and alkyl salicylic acid 100 parts (C 14 -C 18 The mass ratio of the alkyl salicylic acid and C 24 -C 28 The mass ratio of the alkyl salicylic acid and C

[0070] Carbonation reaction: add the accelerator 5 parts, second magnesium oxide 15 parts to the product of the above reaction, and pass 30 parts of carbon dioxide within 2 h, while dropping the mixture of second methanol (15 parts) and pure water (15 parts) (the dropping time is controlled for 1 h), and then increase the temperature to 120 ℃ to remove methanol, water and part of xylene in the system. After centrifugation to remove slag and reduced pressure distillation, the overbased magnesium detergent is obtained.

[0071] Comparative example 2

[0072] The present comparative example provides a preparation method of a magnesium detergent, comprising the following steps:

[0073] Preparation of the accelerator: add neodecanoic acid 7 g into a beaker, slowly add ethylenediamine 4.5 g under stirring, and continue stirring for 0.5 h to obtain the accelerator.

[0074] Neutralization reaction: add 150SN 100 parts, xylene 300 parts, first methanol 5 parts and alkyl salicylic acid 100 parts (C 14 -C 18 The mass ratio of the alkyl salicylic acid and C 24 -C 28 The mass ratio of the alkyl salicylic acid and C

[0075] Carbonation reaction: to the product of the above reaction, add the above-mentioned accelerator 5 parts, the second magnesium oxide 15 parts, and pass 30 parts of carbon dioxide in 2 hours, while adding a mixture of the second methanol (15 parts) and pure water (15 parts) dropwise (control the dropwise time for 1 hour), after the end of the aeration, the temperature is raised to 120°C to remove methanol, water and part of the xylene in the system, the crude product is centrifuged to remove slag, and distilled under reduced pressure to obtain the overbased magnesium detergent.

[0076] Comparative example 3

[0077] The present comparative example provides a method for preparing a magnesium detergent, comprising the following steps:

[0078] Preparation of accelerator: add formic acid 5 g and neodecanoic acid 7 g to a beaker, slowly add 4.7 g of ammonia water (concentration about 28%) under stirring, continue stirring for 0.5 h, and then the accelerator is obtained.

[0079] Neutralization reaction: add 150SN 100 parts, xylene 300 parts, the first methanol 5 parts and alkyl salicylic acid 100 parts (C 14 -C 18 The mass ratio of alkyl salicylic acid to C 24 -C 28 The mass ratio of alkyl salicylic acid to C

[0080] Carbonation reaction: to the product of the above reaction, add the above-mentioned accelerator 5 parts, the second magnesium oxide 15 parts, and pass 30 parts of carbon dioxide in 2 hours, while adding a mixture of the second methanol (15 parts) and pure water (15 parts) dropwise (control the dropwise time for 1 hour), after the end of the aeration, the temperature is raised to 120°C to remove methanol, water and part of the xylene in the system, the crude product is centrifuged to remove slag, and distilled under reduced pressure to obtain the overbased magnesium detergent.

[0081] Comparative example 4

[0082] The present comparative example provides a method for preparing a magnesium detergent, comprising the following steps:

[0083] Preparation of accelerator: add formic acid 5 g and neodecanoic acid 7 g to a beaker, slowly add 4.7 g of ammonia water (concentration about 28%) under stirring, continue stirring for 0.5 h, and then the accelerator is obtained.

[0084] Neutralization reaction: add 150SN 100 parts, xylene 300 parts, the first methanol 5 parts and alkyl salicylic acid 100 parts (C 14 -C 18 The mass ratio of alkyl salicylic acid to C 24 -C 28The alkyl salicylic acid was added to the product of the above reaction, and the mixture was stirred and heated to 50°C. After 1 hour of incubation, the first portion of magnesium oxide (10 parts) and pure water (5 parts) were added, and the mixture was incubated at 50°C for 2 hours.

[0085] Carbonation reaction: To the product of the above reaction, the above-mentioned promoter 5 parts, the second portion of magnesium oxide 15 parts were added, and 30 parts of carbon dioxide were introduced within 2 hours, while a mixture of the second portion of methanol (15 parts) and pure water (10 parts) was added dropwise (the dropwise addition time was controlled for 1 hour). After the end of the aeration, the temperature was increased to 120°C to remove methanol, water and part of dimethylbenzene in the system. After centrifugation to remove slag and reduced pressure distillation, the overbased magnesium detergent was obtained.

[0086] Experimental example

[0087] The magnesium detergents of the above examples and comparative examples were tested for coarse sediment and colloidal stability,

[0088] Coarse sediment measurement method: After removing all alcohols, water and solvents at the end of synthesis, 50g of sample and 40g of n-heptane were placed in a 100mL centrifuge tube, shaken uniformly and centrifuged at 2000rmp for 40min, and the volume of the lower sediment was read.

[0089] Colloidal stability: 50mL of overbased magnesium detergent and 50mL of kerosene were mixed and stirred at room temperature, then placed in a 100mL centrifuge tube, and the volume of the lower sediment was read after 7 days at room temperature.

[0090] The test results are shown in Table 1.

[0091] Table 1

[0092]

[0093] *: The coarse sediment is the volume of sediment per 100g of sample.

[0094] As can be seen from the data results of the examples in Table 1, the total base number of the overbased magnesium detergent of the present application is not less than 290mgKOH / g, the kinematic viscosity is not more than 100mm 2 / s, and the volume percentage of coarse sediment is less than 2.0%.

[0095] In the preparation process of the promoter of Comparative Example 1, no C8-C 10 fatty acid was added, resulting in that the magnesium oxide could not enter the colloid after forming magnesium carbonate, and was precipitated from the reaction system, becoming solid waste;

[0096] In the preparation process of the promoter of Comparative Example 2, no short-chain carboxylic acid was added, resulting in more coarse sediment and increased kinematic viscosity;

[0097] In Comparative Example 3, the organic amine is ammonia water, resulting in more coarse sediment;

[0098] The addition of water in the neutralization stage of Comparative Example 4 resulted in the formation of a large amount of magnesium hydroxide, which could not be converted into magnesium carbonate in time due to the lower solubility product of magnesium hydroxide compared to magnesium carbonate, and finally associated to form a precipitate.

Claims

1. A process for the preparation of a low-deposit overbased magnesium detergent, wherein, The method comprises the following steps: carboxylic acids, C8-C 10 fatty acids, organic amines, to obtain accelerators; mineral oil, solvent oil, a first low-carbon alcohol, alkyl salicylic acid are subjected to a first heating reaction, and then a first magnesium oxide is added to perform a second heating reaction; the product of the above reaction is added with the promoter and a second magnesium oxide, and then carbonation is performed, after the reaction is completed, a post-treatment step is performed to obtain the overbased magnesium detergent; wherein the molar ratio of short chain carboxylic acid, C8-C 10 fatty acid, organic amine is (1-1.5):(0.5-1):

1.

2. The production method according to claim 1, wherein, the amount of the solvent oil added is 250-350 parts by weight based on 100 parts by weight of the mineral oil, the amount of the first low-carbon alcohol added is 5-15 parts, the amount of the alkyl salicylic acid added is 100 parts, the amount of the first magnesium oxide added is 10-15 parts, the amount of the promoter added is 5-8 parts, and the amount of the second magnesium oxide added is 15-20 parts.

3. The production method according to claim 1, wherein the short-chain carboxylic acid is selected from formic acid and / or acetic acid; and / or, the C8-C 10 fatty acid is selected from one or a combination of two or more of n-octanoic acid, iso-octanoic acid, iso-nonyl acid, neodecanoic acid; and / or, the organic amine is selected from one or a combination of two or more of ethylenediamine, ethanolamine and diethanolamine.

4. The production method according to claim 1, wherein short-chain carboxylic acids, C8-C 10 The reaction time of the short-chain carboxylic acids, C8-C 5. The production method according to claim 1, wherein the mineral oil is selected from one or a combination of two or more of 100N, 150SN, 150N, 500N and 500SN; and / or, the solvent oil is an alkane-based solvent oil; and / or, the first low-carbon alcohol is a C1-C4 low-carbon alcohol; and / or the alkyl salicylic acid is a C 14 -C 30 alkyl salicylic acid of the formula 6. The production method according to claim 1, wherein the temperature of the first heating reaction is 40-50 ℃, and the time is 1-2 h; and / or, the temperature of the second heating reaction is 50-60 ℃, and the time is 1-2 h.

7. The production method according to claim 1, wherein the product of the above reaction is added with the promoter and a second magnesium oxide, and then carbon dioxide is introduced, while a mixture of a second low-carbon alcohol and water is added dropwise within 1-3 h; preferably, the amount of the carbon dioxide introduced is 30-50 parts by weight based on 100 parts by weight of the mineral oil; preferably, the time for introducing the carbon dioxide is 2-4 h.

8. The production method according to claim 1, wherein the post-treatment step comprises the following steps: heating to 100-135 ℃, and then centrifugal separation and reduced-pressure distillation.

9. An overbased magnesium detergent prepared by the preparation method according to any one of claims 1-8.

10. A lubricating oil composition prepared by the overbased magnesium detergent prepared by the preparation method according to any one of claims 1-8 or the overbased magnesium detergent according to claim 9.

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