Preparation method of 3-(3, 5-di-tert-butyl-4-hydroxyphenyl) isooctyl propionate

Abstract

The invention provides a preparation method of 3-(3, 5-di-tert-butyl-4-hydroxyphenyl) isooctyl propionate, and belongs to the technical field of preparation of lubricating oil additives. The preparation method comprises the following steps: mixing methyl 3-(3, 5-di-tert-butyl-4-hydroxyphenyl) propionate, isooctanol and a catalyst dialkyl dithiophosphate metal salt, replacing in an inert atmosphere, and heating to carry out transesterification, thereby obtaining the 3-(3, 5-di-tert-butyl-4-hydroxyphenyl) propionate. The dialkyl dithiophosphate metal salt catalyst used in the invention does not need to be removed, the product can be directly applied to the field of lubricating oil, the problems that the catalyst is difficult to remove and post-treatment processes such as washing are complicated in the current 3-(3, 5-di-tert-butyl-4-hydroxyphenyl) isooctyl propionate production process are effectively solved, environmental pollution factors are greatly reduced, and the production cost is reduced. Moreover, the product is high in yield, high in purity and good in quality, and the method is an energy-saving, environment-friendly, simple and economical production method.

Description

Technical Field

[0001] This invention belongs to the field of lubricant additive preparation technology, and relates to a method for preparing isooctyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate. Background Technology

[0002] To mitigate the oxidative deterioration of lubricating oils and other oil products, extend their service life, and prevent corrosion of components, antioxidants and antioxidant-corrosion inhibitors are added to the oils. These agents inhibit oil oxidation, form a protective film on metal surfaces, and passivate the catalytic effect of the metal on the oil. Among these, hindered phenols and aromatic amines are the most important antioxidant systems. However, aromatic amines are toxic and have been gradually replaced by hindered phenols.

[0003] 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate isooctyl ester, with the molecular formula C 25 H 42 O3, in its pure form, is a colorless to pale yellow transparent liquid. It exhibits good antioxidant properties and excellent thermal stability under high-temperature conditions, effectively inhibiting the formation of deposits in oils. As a typical hindered phenolic antioxidant, its combination with ZDDP can meet the antioxidant requirements of industries such as industrial lubricants, high-grade internal combustion engine oils, and transmission fluids.

[0004] Isooctyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate is obtained by transesterification of methyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate (abbreviated as 3,5-methyl ester) with isooctyl alcohol. The specific reaction equation is as follows:

[0005]

[0006] There are currently several methods for preparing isooctyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, the main differences being the type of catalyst and the removal method.

[0007] US patents US3330859 and US5892097 both employ tin-based catalysts in their preparation methods. The resulting waste from post-treatment has an adverse impact on the environment, and its use is strictly limited.

[0008] Chinese invention patent application CN101168508A discloses a method for preparing a liquid phenolic antioxidant, which uses aluminum isopropoxide as a catalyst and removes the catalyst with an acid solution after the reaction. This method generates a large amount of wastewater.

[0009] Chinese invention patent CN102030647B discloses a clean production method for preparing liquid antioxidants. This method also uses dibutyltin oxide as a catalyst, but an adsorbent is used to remove the catalyst in the post-processing. Although this method does not produce wastewater, it produces waste residue and has problems such as easy discoloration of the product during storage.

[0010] The School of Chemical Engineering at Xi'an Petroleum University has developed a method for preparing an organic titanium catalyst. In the post-treatment process, the catalyst is washed away with water and the product is obtained by gasoline extraction. However, this method not only generates wastewater but also involves a complex post-treatment process.

[0011] Chinese invention patent CN103420839B provides a method for preparing isooctyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, which uses titanate esters as catalysts and employs a polybasic organic acid to remove the catalyst. This method does not produce wastewater or adsorption residue, but it does produce a certain amount of complexes between titanate esters and polybasic acids.

[0012] Therefore, in order to achieve the goal of energy conservation and environmental protection, the preparation process of hindered phenolic catalysts such as isooctyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate still needs to be optimized. Summary of the Invention

[0013] To address the problems existing in the prior art, this invention provides a method for preparing isooctyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate. The isooctyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate of this invention is obtained by reacting methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate with isooctyl alcohol under reduced pressure using a dialkyl dithiophosphate metal salt as a catalyst. Since the dialkyl dithiophosphate metal salt catalyst can be applied to the lubricating oil field without product removal, it not only effectively solves the post-processing and environmental pollution problems in current production processes, but also results in high product yield, purity, and quality. It is an energy-saving, environmentally friendly, simple, and economical production method.

[0014] To achieve the above objectives, the technical solution of the present invention is as follows:

[0015] This invention provides a method for preparing isooctyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate. The specific process is as follows: methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, isooctyl alcohol and dialkyl dithiophosphate metal salt catalyst are mixed, and after being replaced by an inert atmosphere, the mixture is heated to carry out an ester exchange reaction to obtain the product.

[0016] Furthermore, the catalyst dialkyl dithiophosphate metal salt is selected from one or more of the following general structural formulas;

[0017]

[0018] Wherein, R is selected from any one of propyl, isopropyl, n-butyl, isobutyl, pentyl, n-hexyl, 2-hexyl, isooctyl, n-decyl, and n-dodecyl; X is selected from any one of Cu, Zn, Cd, and Pb.

[0019] According to the preparation method of claim 2, the catalyst is selected from one or more of dialkyl dithiophosphate copper, dialkyl dithiophosphate zinc, dialkyl dithiophosphate cadmium, and dialkyl dithiophosphate lead.

[0020] Preferably, the catalyst is a dialkyl dithiophosphate metal salt, which is zinc dialkyl dithiophosphate.

[0021] More preferably, the catalyst, dialkyl dithiophosphate zinc, is selected from one or more of butyric zinc dithiophosphate, diisopropyl zinc dithiophosphate, diisooctyl zinc dithiophosphate, and propane-octyl sec-alkyl zinc dithiophosphate.

[0022] More preferably, the catalyst, zinc dialkyl dithiophosphate, is selected from one or more of zinc butyl alkyl dithiophosphate, zinc diisooctyl dithiophosphate, and zinc propyl octyl sec-alkyl dithiophosphate.

[0023] Preferably, the molar ratio of methyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate to isooctyl alcohol is 1:1.0-3.0.

[0024] Furthermore, the molar ratio of methyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate to the catalyst is 1:0.001-0.03.

[0025] Furthermore, the transesterification reaction temperature is 80-160℃; the reaction time is 2-8h.

[0026] In some embodiments of the present invention, the transesterification reaction is carried out by gradually increasing the temperature, with the first stage heating to 80-100°C and the second stage heating to 100-160°C.

[0027] Furthermore, the preparation method further includes: removing methanol and excess isooctyl alcohol produced by the reaction under reduced pressure after the transesterification reaction is completed.

[0028] Furthermore, the decompression temperature is 100-160℃, and the decompression time is 2-8h.

[0029] Furthermore, the reduced pressure temperature is higher than the transesterification reaction temperature.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) The catalyst used in the preparation process of isooctyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate of the present invention does not need to be removed. It utilizes the synergistic effect of isooctyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and catalyst in the field of lubricating oil. The preparation method of the present invention yields products with high yield (over 95%), high purity (greater than 99.00%, isooctyl alcohol content less than 0.20%, 3,5-methyl ester content less than 0.20%), and good quality. Its performance is comparable to that of existing commercially available antioxidants, and it effectively solves the problems of post-processing and environmental pollution in the current production process.

[0032] (2) The preparation process of isooctyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate of the present invention is simple. The isooctyl alcohol removed by vacuum can be recycled and reused in the preparation of isooctyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, realizing the recycling of raw materials. Moreover, the reaction conditions are mild, which is an energy-saving, environmentally friendly, simple and economical production method. Attached Figure Description

[0033] Figure 1 The infrared spectrum of isooctyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate prepared in Example 1 of this invention;

[0034] Figure 2 The liquid chromatogram of isooctyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate prepared in Example 1 of this invention. Detailed Implementation

[0035] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified, specific conditions were applied in the examples. Reagents or instruments used, unless otherwise specified, are all commercially available products.

[0036] Example 1

[0037] A method for preparing isooctyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, comprising the following steps:

[0038] 73 g of 3,5-methyl ester, 40 g of isooctyl alcohol, and 0.5 g of zinc diisooctyl dithiophosphate were added in a single batch to a 250 mL four-necked reaction flask at room temperature. A small amount of nitrogen gas (0.2 L / min) was introduced, and the mixture was stirred until it reached 80 °C to initiate the reaction. The reaction temperature was gradually increased, reaching 135 °C after 4 hours. Then, a vacuum system was activated for decompression, and the reaction temperature was gradually increased to 160 °C and the vacuum level to -0.099 MPa. The decompression time was controlled to be 6 hours. After the decompression was completed, the mixture was cooled to room temperature to obtain a transparent liquid, 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate isooctyl ester, with a yield of 95.2% and a purity of 99.71%.

[0039] Example 2

[0040] A method for preparing isooctyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, comprising the following steps:

[0041] 73 g of 3,5-methyl ester, 32.5 g of isooctyl alcohol, and 7.2 g of copper butyric acid dithiophosphate were added in a single batch to a 250 mL four-necked reaction flask at room temperature. A small amount of nitrogen gas (0.2 L / min) was introduced, and the mixture was stirred until it reached 100 °C to initiate the reaction. The reaction temperature was gradually increased, reaching 160 °C after 4 hours. Then, a vacuum system was activated to reduce the pressure, and the vacuum level was gradually increased to -0.099 MPa for 3 hours. After the pressure reduction was completed, the mixture was cooled to room temperature to obtain a transparent liquid, 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate isooctyl ester, with a yield of 94.8% and a purity of 98.5%.

[0042] Example 3

[0043] A method for preparing isooctyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, comprising the following steps:

[0044] 73 g of 3,5-methyl ester, 38 g of isooctyl alcohol, and 0.3 g of zinc propionate-octyl dimethyl dithiophosphate were added in a single batch to a 250 mL four-necked reaction flask at room temperature. A small amount of nitrogen gas (0.2 L / min) was introduced, and the mixture was stirred until it reached 90 °C to initiate the reaction. The reaction temperature was gradually increased, reaching 140 °C after 4 hours. Then, a vacuum system was turned on to reduce the pressure, and the reaction temperature was gradually increased to 160 °C and the vacuum degree to -0.099 MPa. The pressure reduction time was controlled at 2 hours. After the pressure reduction was completed, the mixture was cooled to room temperature to obtain a transparent liquid, 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate isooctyl ester, with a yield of 95.0% and a purity of 99.53%.

[0045] Example 4

[0046] A method for preparing isooctyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, comprising the following steps:

[0047] (1) 73 g of 3,5-methyl ester, 65 g of isooctyl alcohol, and 3.8 g of cadmium didodecyl dithiophosphate were added to a 250 mL four-necked reaction flask at room temperature. A small amount of nitrogen gas (0.2 L / min) was introduced and the mixture was heated to 90 °C under stirring to start the reaction. The reaction temperature was gradually increased to 135 °C after 4 hours. Then, the vacuum system was turned on to reduce the pressure and the reaction temperature was gradually increased to 150 °C and the vacuum degree was -0.099 MPa. The pressure reduction time was controlled at 5 hours. After the pressure reduction was completed, the mixture was cooled to room temperature to obtain a transparent liquid, 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate isooctyl ester, with a yield of 94.6% and a purity of 99.32%.

[0048] Example 5

[0049] A method for preparing isooctyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, comprising the following steps:

[0050] (1) 73g of 3,5-methyl ester, 97g of isooctyl alcohol, and 3.5g of zinc diisopropyl dithiophosphate were added to a 250mL four-necked reaction flask at room temperature. A small amount of nitrogen gas (0.2L / min) was introduced and the temperature was raised to 80℃ under stirring to start the reaction. The reaction temperature was gradually increased to 125℃ after 3 hours. Then, the vacuum system was turned on to reduce the pressure and the reaction temperature was gradually increased to 160℃ and the vacuum degree was -0.099MPa. The pressure reduction time was controlled at 6 hours. After the pressure reduction was completed, the temperature was cooled to room temperature to obtain a transparent liquid 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate isooctyl ester with a yield of 95.0% and a purity of 99.43%.

[0051] Comparative Example 1

[0052] Compared to Example 1, the only difference is that the amount of isooctanol is 26g. Specifically, 73g of 3,5-methyl ester, 26g of isooctanol, and 0.5g of zinc diisooctyl dithiophosphate were added at room temperature to a 250mL four-necked reaction flask, and a small amount of nitrogen gas (0.2L / min) was introduced. The mixture was stirred and heated to 80°C to start the reaction. The reaction temperature was gradually increased, reaching 135°C after 4 hours. Then, a vacuum system was turned on for decompression, and the reaction temperature was gradually increased to 160°C and the vacuum degree to -0.099MPa. The decompression time was controlled at 6 hours. After the decompression was completed, the mixture was cooled to room temperature to obtain a transparent liquid, 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate isooctyl ester, with a yield of 78.0% and a purity of 98.5%.

[0053] Comparative Example 2

[0054] Compared to Example 1, the only difference is that the amount of isooctanol is 400g. Specifically, 73g of 3,5-methyl ester, 400g of isooctanol, and 0.5g of zinc diisooctyl dithiophosphate were added at room temperature to a 250mL four-necked reaction flask, and a small amount of nitrogen gas (0.2L / min) was introduced. The mixture was stirred and heated to 80°C to start the reaction. The reaction temperature was gradually increased, reaching 135°C after 4 hours. Then, a vacuum system was turned on for decompression, and the reaction temperature was gradually increased to 160°C and the vacuum degree to -0.099MPa. The decompression time was controlled at 6 hours. After the decompression was completed, the mixture was cooled to room temperature to obtain a transparent liquid, 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate isooctyl ester, with a yield of 82.0% and a purity of 96.8%.

[0055] The basic performance indicators of Embodiments 1, 3, and 5 of the present invention and commercially available products were tested, and the results are shown in Table 1.

[0056] Table 1. Performance characterization results of different isooctyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate esters

[0057]

[0058]

[0059] The key indicators of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate prepared in Examples 1, 3, and 5 of this invention are consistent with those of commercially available products. This invention provides a specific preparation method and the catalyst does not require post-treatment.

[0060] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing isooctyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, characterized in that, Methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, isooctyl alcohol, and dialkyl dithiophosphate metal salt catalyst are mixed, purged under an inert atmosphere, and then heated to carry out an ester exchange reaction to obtain the product.

2. The preparation method according to claim 1, characterized in that, The catalyst dialkyl dithiophosphate metal salt is selected from one or more of the following general structural formulas; Wherein, R is selected from any one of propyl, isopropyl, n-butyl, isobutyl, pentyl, n-hexyl, 2-hexyl, isooctyl, n-decyl, and n-dodecyl; X is selected from any one of Cu, Zn, Cd, and Pb.

3. The preparation method according to claim 2, characterized in that, The catalyst is selected from one or more of dialkyl dithiophosphate copper, dialkyl dithiophosphate zinc, dialkyl dithiophosphate cadmium, and dialkyl dithiophosphate lead.

4. The preparation method according to claim 1, characterized in that, The molar ratio of methyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate to isooctyl alcohol is 1:1.0-3.

0.

5. The preparation method according to claim 1, characterized in that, The molar ratio of methyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate to the catalyst is 1:0.001-0.

03.

6. The preparation method according to claim 1, characterized in that, The transesterification reaction temperature is 80-160℃; the reaction time is 2-8h.

7. The preparation method according to claim 1, characterized in that, The transesterification reaction is carried out by gradually increasing the temperature, with the first stage heating to 80-100℃ and the second stage heating to 100-160℃.

8. The preparation method according to claim 1, characterized in that, Also includes: After the transesterification reaction is completed, methanol and excess isooctyl alcohol produced in the reaction are removed by depressurization.

9. The preparation method according to claim 8, characterized in that, The decompression temperature is 100-160℃, and the decompression time is 2-8h.

10. The preparation method according to claim 9, characterized in that, The decompression temperature is higher than the transesterification reaction temperature.

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