A method for preparing polyisobutylene oil for viscosity standard material

Abstract

The invention belongs to the technical field of viscosity standard materials, and specifically relates to a method for preparing polyisobutylene oil for viscosity standard materials. The preparation method is as follows: low molecular weight polyisobutylene, alkane thiol and a catalyst are reacted under nitrogen protection to obtain a colorless transparent liquid, namely the polyisobutylene oil. The preparation method modifies the low molecular weight polyisobutylene, reduces the content of double bonds in the structure, improves the stability of the polyisobutylene, and is conducive to the application of the polyisobutylene in the field of viscosity standard materials.

Description

Technical Field

[0001] The invention belongs to the technical field of viscosity standard substances, and particularly relates to a method for preparing polyisobutylene oil for viscosity standard substances. Background Art

[0002] A standard substance refers to a substance or material that has been determined to have one or more sufficiently uniform characteristic values. It has the accuracy, uniformity, and stability of the characteristic values, and plays an important role in calibrating measuring instruments and devices, evaluating measurement and analysis methods, measuring the characteristic values ​​of substances or materials, and assessing the operational technical level of analysts. Viscosity is a measure of the viscosity of a fluid, and is a representation of the fluid flow force on its internal friction phenomenon. High viscosity indicates high internal friction. The larger the molecular weight, the more carbon and hydrogen bonds there are, and the greater this force. Viscosity is of decisive significance to various lubricants, quality identification and determination of use, as well as the combustion performance and cost of various fuel oils. Therefore, the development of viscosity standard substances is of great significance in the fields of national defense, military industry, industrial production, and aerospace.

[0003] Viscosity standard materials have three characteristics: Newtonianity, stability and viscosity-temperature property. Newtonianity means that the stress of the fluid is proportional to the shear rate, and the viscosity of the fluid is only related to the temperature, but not to the shear rate. Stability means that the viscosity of the fluid does not change within a certain storage time. Viscosity-temperature property means that the viscosity changes less with temperature. With the continuous deepening of research, mineral oil, silicone oil, polyisobutylene, etc. have been used for the development and production of viscosity standard materials. Among them, compared with silicone oil, mineral oil, etc., low molecular weight polyisobutylene (LMPIB), as a saturated alkane, is non-toxic, colorless, odorless, has better thermal stability, chemical resistance and weather resistance, etc., and has no residual carbon after cracking, so it is widely used in lubricant additives, electrical insulation materials, fuel additives, adhesives, putty glue and other polymer blending and modification fields. However, due to chain transfer reactions and chain termination reactions, the polyisobutylene chain ends purchased on the market usually contain unsaturated double bonds. According to the chemical structure of the terminal double bond, polyisobutylene can be divided into ordinary polyisobutylene and reactive polyisobutylene. The terminal α-olefin content of ordinary polyisobutylene is less than 15%, and the other structures are mainly β-olefin and internal olefin; reactive polyisobutylene refers to polyisobutylene with a terminal α-olefin structure content of more than 70%, and the α-olefin structure content of commercial reactive polyisobutylene is usually more than 80%.

[0004] Compared with viscosity standard materials such as silicone oil and mineral oil, low molecular weight polyisobutylene (LMPIB), as a saturated alkane, has better thermal stability, chemical resistance and weather resistance. However, the LMPIB currently available on the market contains active ingredients such as α-olefins and β-olefins, which are very prone to oxidation and cross-linking reactions during storage, resulting in large changes in viscosity, which violates the characteristics of uniformity and stability of viscosity standard materials, greatly limiting the application of polyisobutylene in the field of viscosity standard materials. The existence of α-olefin and β-olefin structures has become a problem that needs to be solved urgently in the application of polyisobutylene in viscosity standard materials. Summary of the invention

[0005] In view of the existing problems, the present invention provides a method for preparing polyisobutylene oil for viscosity standard material. The preparation method modifies LMPIB (low molecular weight polyisobutylene) to reduce the content of double bonds in the structure and improve the stability of polyisobutylene, which is beneficial to the application of polyisobutylene in the field of viscosity standard material.

[0006] The technical solution of the present invention is as follows:

[0007] A method for preparing polyisobutylene oil for viscosity standard material: low molecular weight polyisobutylene, alkane thiol and catalyst react under nitrogen protection to obtain colorless transparent liquid.

[0008] Preferably, the molar ratio of low molecular weight polyisobutylene to alkane thiol is 100:1-100.

[0009] Preferably, the amount of the catalyst is 0-0.1 times the amount of the alkane thiol.

[0010] Preferably, the solvent selected in the reaction system is one of tetrahydrofuran, chloroform, N,N-dimethylformamide and N,N-dimethylacetamide. Further preferably, the amount of the solvent used is 30-80 wt % of the entire reaction system.

[0011] Preferably, the catalyst is one of benzoin dimethyl ether, azobisisobutyronitrile and diphenyl ether, wherein benzoin dimethyl ether and diphenyl ether are used under ultraviolet light irradiation, and azobisisobutyronitrile is used under heating conditions, and the heating temperature is 60-90°C.

[0012] Preferably, the colorless transparent liquid is washed with anhydrous ethanol or methanol, the lower polyisobutylene phase is collected and dried to finally obtain polyisobutylene oil. Further preferably, the polyisobutylene oil is dried under vacuum at 50-90° C. for 10-20 hours.

[0013] Preferably, the low molecular weight polyisobutylene has an average molecular weight of 200-1500 g / mol.

[0014] Preferably, the reaction is carried out for 10-24 hours.

[0015] Since LMPIB contains active ingredients such as α-olefins and β-olefins, it is very easy to have oxidation, cross-linking and other reactions during storage. The inventors found in the process of exploration that: since the thiol group has high activity, it is very easy to react with double bonds under the action of a catalyst. After the reaction is completed, the post-processing is simple and convenient, and a product with stable performance can be obtained; during the reaction process, a light / heat initiation system is used, which is pollution-free and highly operable, greatly reducing the production cost; the thiol group and the olefin in the polyisobutylene structure undergo a click reaction, and the viscosity of the polyisobutylene is kept stable during storage by reducing the double bond content of the polyisobutylene, meeting the requirements for the preparation of polyisobutylene for standard substances. The thiol click reaction has the advantages of high efficiency, few side reactions, and mild reaction conditions. The present invention combines the characteristics of thiol alkane and polyisobutylene to implement the thiol click reaction, synthesizes a modified low molecular weight polyisobutylene of a saturated alkane, and successfully uses it for viscosity standard substances.

[0016] The process of modifying the viscosity standard material of the present invention with polyisobutylene oil is as follows:

[0017]

[0018] Wherein, R = saturated alkane (methane, ethane, butane, etc.), n = y + z.

[0019] The invention provides a method for preparing polyisobutylene oil for viscosity standard material. The double bond content in the structure of polyisobutylene for viscosity standard material is reduced by thiol click reaction. The modified polyisobutylene avoids the re-reaction of the double bond structure during use, so that the viscosity of the polyisobutylene is kept stable during storage, which is more conducive to the application of polyisobutylene as viscosity standard material. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is the PIB400 NMR hydrogen spectrum;

[0021] Figure 2 This is the H NMR spectrum of the polyisobutylene prepared in Example 1;

[0022] Figure 3 The infrared spectrum of the polyisobutylene prepared in Example 1;

[0023] Figure 4 This is the H NMR spectrum of the polyisobutylene prepared in Example 2;

[0024] Figure 5 This is the infrared spectrum of the polyisobutylene prepared in Example 3-5. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0026] The following polyisobutylene 400 (PIB400) indicates that the average molecular weight of polyisobutylene is 400 g / mol, polyisobutylene 800 indicates that the average molecular weight of polyisobutylene is 800 g / mol, and polyisobutylene 1300 indicates that the average molecular weight of polyisobutylene is 1300 g / mol. The above polyisobutylene can be purchased from the market, and specifically, Dalin of Korea is selected.

[0027] Example 1

[0028] A method for preparing polyisobutylene oil for viscosity standard material comprises the following steps: adding polyisobutylene 400 (PIB400, 0.01 mol), mercapto octane (0.01 mol), photocatalyst benzoin dimethyl ether (0.001 mol) and solvent tetrahydrofuran (10 mL) into a 50 ml single-necked flask, evacuating the flask, irradiating the flask with ultraviolet light under nitrogen protection, reacting the flask at room temperature for 18 hours to obtain a colorless transparent liquid, washing the reaction product with anhydrous ethanol for multiple times after the reaction is completed, separating the solution into layers after standing, collecting the lower polyisobutylene phase, and performing hollow drying at 50° C. for 10 hours to finally obtain modified polyisobutylene oil for viscosity standard material.

[0029] Example 2

[0030] A method for preparing polyisobutylene oil for viscosity standard material comprises the following steps: adding polyisobutylene 400 (0.15 mol), mercaptopropane (0.15 mol), photocatalyst benzoin dimethyl ether (0.0015 mol) and solvent tetrahydrofuran (80 mL) into a 250 ml single-necked flask, evacuating the flask, irradiating the flask with ultraviolet light under nitrogen protection, reacting the flask at room temperature for 18 hours to obtain a colorless transparent liquid, and obtaining a colorless transparent liquid after the reaction is completed. After rotary evaporation, a light yellow transparent liquid is obtained. The reaction product is washed with anhydrous ethanol for multiple times. After standing, the solution is separated into layers, the lower polyisobutylene phase is collected, and the solution is dried in air at 50° C. for 10 hours to finally obtain modified polyisobutylene oil for viscosity standard material.

[0031] Example 3

[0032] A method for preparing polyisobutylene oil for viscosity standard material: polyisobutylene 400 (0.15 mol), mercaptobutane (0.15 mol), photocatalyst benzoin dimethyl ether (0.0015 mol) and solvent tetrahydrofuran (80 mL) are added into a 250 ml single-necked flask, and the mixture is evacuated. The mixture is reacted at room temperature for 18 hours under nitrogen and ultraviolet light to obtain a colorless transparent liquid. After the reaction is completed, a colorless transparent liquid is obtained. After rotary evaporation, a light yellow transparent liquid is obtained. The reaction product is washed with anhydrous ethanol for multiple times. After standing, the solution is separated into layers. The lower polyisobutylene phase is collected and dried in air at 50° C. for 10 hours to finally obtain modified polyisobutylene oil for viscosity standard material.

[0033] Example 4

[0034] A method for preparing polyisobutylene oil for viscosity standard material: polyisobutylene 400 (0.15 mol), mercaptohexane (0.15 mol), photocatalyst benzoin dimethyl ether (0.0015 mol) and solvent tetrahydrofuran (80 mL) are added into a 250 ml single-necked flask, and the mixture is evacuated. The mixture is reacted at room temperature for 18 hours under nitrogen and ultraviolet light to obtain a colorless transparent liquid. After the reaction is completed, a colorless transparent liquid is obtained. After rotary evaporation, a light yellow transparent liquid is obtained. The reaction product is washed with anhydrous ethanol for multiple times. After standing, the solution is separated into layers. The lower polyisobutylene phase is collected and dried in air at 50° C. for 15 hours to finally obtain modified polyisobutylene oil for viscosity standard material.

[0035] Example 5

[0036] A method for preparing polyisobutylene oil for viscosity standard material: polyisobutylene 400 (0.15 mol), mercaptoheptane (0.15 mol), photocatalyst benzoin dimethyl ether (0.0015 mol) and solvent tetrahydrofuran (80 mL) are added into a 250 ml single-necked flask, vacuumized, reacted at room temperature for 18 hours under nitrogen and ultraviolet light to obtain a colorless transparent liquid, a colorless transparent liquid is obtained after the reaction is completed, a light yellow transparent liquid is obtained after rotary evaporation, the reaction product is washed with anhydrous ethanol for multiple times, the solution is separated after standing, the lower polyisobutylene phase is collected, and air-dried at 50° C. for 10 hours to finally obtain modified polyisobutylene oil for viscosity standard material.

[0037] Example 6

[0038] A method for preparing polyisobutylene oil for viscosity standard material: polyisobutylene 400 (0.15 mol), mercapto octane (0.15 mol), photocatalyst benzoin dimethyl ether (0.0015 mol) and solvent tetrahydrofuran (80 mL) are added into a 250 ml single-necked flask, and the mixture is evacuated. The mixture is reacted at room temperature for 18 hours under nitrogen and ultraviolet light to obtain a colorless transparent liquid. After the reaction is completed, a colorless transparent liquid is obtained. After rotary evaporation, a light yellow transparent liquid is obtained. The reaction product is washed with anhydrous ethanol for multiple times. After standing, the solution is separated into layers. The lower polyisobutylene phase is collected and dried in air at 50° C. for 10 hours to finally obtain modified polyisobutylene oil for viscosity standard material.

[0039] Example 7

[0040] A method for preparing polyisobutylene oil for viscosity standard material: polyisobutylene 400 (0.2 mol), mercaptopropane (0.2 mol), photocatalyst benzoin dimethyl ether (0.01 mol) and solvent tetrahydrofuran (150 mL) are added into a 500 ml single-necked flask, vacuumized, reacted at room temperature for 24 hours under nitrogen and ultraviolet light to obtain a colorless transparent liquid, a colorless transparent liquid is obtained after the reaction is completed, a light yellow transparent liquid is obtained after rotary evaporation, the reaction product is washed with anhydrous ethanol for multiple times, the solution is separated after standing, the lower polyisobutylene phase is collected, and air-dried at 55° C. for 10 hours to finally obtain modified polyisobutylene for viscosity standard material.

[0041] Example 8

[0042] A method for preparing polyisobutylene oil for viscosity standard material: polyisobutylene 800 (0.15 mol), mercaptohexane (0.15 mol), azobisisobutyronitrile (0.015 mol), and chloroform (80 mL) as a solvent are added into a 250 ml single-necked flask, and the mixture is vacuumed, and reacted for 20 hours under nitrogen and heated to 60° C. to obtain a colorless transparent liquid. After the reaction is completed, a colorless transparent liquid is obtained, and a light yellow transparent liquid is obtained after rotary evaporation. The reaction product is washed with anhydrous ethanol for multiple times, and the solution is separated into layers after standing. The lower polyisobutylene phase is collected, and the phase is dried in air at 50° C. for 10 hours to finally obtain modified polyisobutylene for viscosity standard material.

[0043] Example 9

[0044] A method for preparing polyisobutylene oil for viscosity standard material: polyisobutylene 1300 (0.4 mol), mercaptohexane (0.15 mol), photocatalyst diphenyl ether (0.015 mol) and solvent chloroform (80 mL) are added into a 1L single-mouth flask, and the mixture is evacuated. The mixture is reacted at room temperature for 20 hours under nitrogen and ultraviolet light to obtain a colorless transparent liquid. After the reaction is completed, a colorless transparent liquid is obtained. After rotary evaporation, a light yellow transparent liquid is obtained. The reaction product is washed with anhydrous ethanol for multiple times. After standing, the solution is separated into layers. The lower polyisobutylene phase is collected and dried in air at 50°C for 10 hours to finally obtain modified polyisobutylene for viscosity standard material.

[0045] like Figure 1 As shown, PIB400 was characterized by H NMR spectrum with deuterated chloroform as solvent. Among them, the chemical shift at 7.26ppm is the absorption peak of the solvent, the multiple peaks at 0.5-2.0ppm are the chemical shifts of the methyl and methylene groups of the saturated alkanes in the polyisobutylene structure, and the chemical shifts at 4.64ppm and 4.85ppm are the α-olefins obtained by direct deprotonation without isomerization rearrangement in the PIB structure, and the chemical shifts at 5.15ppm and 5.38ppm correspond to the β-olefins obtained by direct deprotonation without isomerization rearrangement of polyisobutylene. Since α-olefins and β-olefins are active groups and are very easy to undergo polymerization reactions, the presence of the two becomes an unstable factor in the application of polyisobutylene as a viscosity standard material, which greatly limits the application of polyisobutylene in viscosity standard materials.

[0046] like Figure 2 As shown, the modified PIB400 obtained by the thiol click reaction of mercapto octane and PIB400 in Example 1 is shown in the nuclear magnetic hydrogen spectrum. In the figure, the chemical shift at 7.26ppm is the absorption peak of deuterated chloroform, and the multiple peaks of the chemical shift at 0.5ppm-2.0ppm are the chemical shifts of the methyl and methylene of the saturated alkanes in the polyisobutylene structure and the alkanes in the mercapto octane structure. In addition, it can be seen from the figure that there is almost no peak generated at the chemical shift of 4.4ppm-5.6ppm, indicating that the α-olefin and β-olefin in the PIB400 structure successfully undergo a click reaction with the thiol group, thereby obtaining a saturated alkane polyisobutylene with stable performance, which can be used as a viscosity standard material.

[0047] Figure 3 This is the infrared absorption spectrum of the modified polyisobutylene oil obtained after the PIB400 click reaction in Example 1. As can be seen from the figure, 2965cm -1 This is the stretching vibration absorption peak of the methyl and methylene groups in the polyisobutylene structure. This peak is relatively strong, indicating that the content of methyl and methylene groups in the structure is relatively high. -1 、1372cm -1The bending vibration peaks of methyl and methylene are at 728cm -1 The absorption peak of CS bond was found, indicating that saturated polyisobutylene with good stability was successfully obtained.

[0048] As shown in Figure 4, in Example 2, mercaptopropane and PIB400 undergo a thiol click reaction, and the modified PIB400 NMR is shown in the figure. In the figure, the chemical shift at 7.26ppm is the absorption peak of deuterated chloroform, and the multiple peaks of the chemical shift at 0.5ppm-2.0ppm are the chemical shifts of the methyl and methylene of the saturated alkanes in the polyisobutylene structure and the alkanes in the mercapto octane structure. In addition, it can be seen from the figure that there is almost no peak generated at the chemical shift of 4.4ppm-5.6ppm, indicating that the α-olefin and β-olefin in the PIB400 structure successfully undergo a click reaction with the thiol group, thereby obtaining a saturated alkane polyisobutylene with stable performance, which can be used as a viscosity standard material.

[0049] Figure 5 This is the infrared absorption spectrum of the modified polyisobutylene oil obtained after the PIB click reaction in Example 3-5. As can be seen from the figure, 2965cm -1 This is the stretching vibration absorption peak of the methyl and methylene groups in the polyisobutylene structure. This peak is relatively strong, indicating that the content of methyl and methylene groups in the structure is relatively high. -1 、1372cm -1 The bending vibration peaks of methyl and methylene are at 728cm -1 The absorption peak of CS bond was found, indicating that saturated polyisobutylene with good stability was successfully obtained.

[0050] Test example

[0051] Table 1 shows the viscosity changes of PIB before and after modification at 20°C (Examples 3-9).

[0052] Table 1. Viscosity changes of PIB before and after modification at 20℃

[0053]

[0054] As can be seen from Table 1, the viscosity of polyisobutylene increased after the thiol click reaction, which is due to the addition of sulfur-containing alkanes in the polymer chain, and also indicates that the double bonds in the polyisobutylene structure did react with the thiol alkanes.

[0055] Stability test

[0056] Table 2 shows the viscosity changes of PIB before and after modification after storage for half a year at 20°C.

[0057] Table 2. Changes in viscosity of PIB before and after modification after storage for a certain period of time at 20°C

[0058]

[0059] The storage stability test of PIB before and after modification is carried out. As can be seen from Table 2, the viscosity change rate of unmodified PIB exceeds 2%, which does not meet the requirement of stability of viscosity standard material less than 1% (GB / T 265). However, the viscosity value of modified PIB changes by only about 0.2% after one year of storage, which is extremely stable, exceeding ten orders of magnitude, indicating that the modified PIB is more stable and meets the requirements of viscosity standard material.

[0060] Uniformity test

[0061] The modified polyisobutylene oil obtained in Example 3 was packaged, and the sampling volume of each bottle was 20 mL. Six bottles of the sample after packaging were randomly selected and tested for uniformity according to the requirements of the fixed value experiment. The test temperature was 20°C, and each bottle was independently sampled and measured twice at the measurement temperature, and the kinematic viscosity was calculated by measuring the outflow time. The presence or absence of systematic errors was determined by comparing the variance within the group and the variance between the groups. At the same time, the measured data was statistically analyzed using the F distribution function. If F≤F (the critical value of the statistical test), the sample was judged to be uniform, otherwise it was non-uniform.

[0062] Table 3 Uniformity test results of Example 3

[0063]

[0064] It can be seen from Table 3 that the modified polyisobutylene oil obtained in Example 3 is uniform and meets the requirements of the viscosity standard material.

[0065] The invention provides a method for preparing polyisobutylene oil for viscosity standard material. The double bond content in the structure of polyisobutylene for viscosity standard material is reduced by thiol click reaction. The modified polyisobutylene avoids the re-reaction of the double bond structure during use, so that the viscosity of the polyisobutylene is kept stable during storage, which is more conducive to the application of polyisobutylene as viscosity standard material.

Claims

1. A method for preparing polyisobutylene oil for viscosity standard material, characterized in that: The preparation method is as follows: low molecular weight polyisobutylene, alkane thiol and catalyst react under nitrogen protection to obtain a colorless transparent liquid; the catalyst is benzoin dimethyl ether; the benzoin dimethyl ether is used under ultraviolet light irradiation; the amount of the catalyst is 0.01-0.1 times the amount of the alkane thiol.

2. The method for preparing a polyisobutylene oil for viscosity standard material according to claim 1, characterized in that: The molar ratio of the low molecular weight polyisobutylene to the alkane thiol is 100:1-100.

3. The method for preparing a polyisobutylene oil for viscosity standard material according to claim 1, characterized in that: The low molecular weight polyisobutylene has an average molecular weight of 200-1500 g / mol.

4. The method for preparing a polyisobutylene oil for viscosity standard material according to claim 1, characterized in that: The colorless transparent liquid is washed with anhydrous ethanol or methanol, and the lower polyisobutylene phase is collected and dried to finally obtain polyisobutylene oil.

5. The method for preparing a polyisobutylene oil for viscosity standard material according to claim 4, characterized in that: The drying is performed by vacuum drying at 50-90° C. for 10-20 hours.

6. The method for preparing a polyisobutylene oil for viscosity standard material according to claim 1, characterized in that: The reaction is carried out for 10-24 hours.

7. The method for preparing a polyisobutylene oil for viscosity standard material according to claim 1, characterized in that: The solvent selected in the reaction system is one of tetrahydrofuran, chloroform, N,N-dimethylformamide and N,N-dimethylacetamide.

8. The method for preparing a polyisobutylene oil for viscosity standard material according to claim 7, characterized in that: The usage amount of the solvent is 30-80wt% of the whole reaction system.

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