Process for the preparation of polyisobutenyl succinic anhydride and process for the preparation of mono polyisobutenyl succinimide

Abstract

The application relates to the field of high polymer synthesis, and discloses a method for preparing polyisobutenyl succinic anhydride and a method for preparing mono-polyisobutenyl succinimide. The method for preparing polyisobutenyl succinic anhydride comprises the following two steps under the protection of an inert atmosphere: (1) mixing polyisobutene with a content of alpha-double bonds of greater than or equal to 75% with maleic anhydride to perform a thermal addition reaction, so as to obtain a thermal addition reaction product; wherein the molar ratio of the polyisobutene to the maleic anhydride is 1:1-1.6; (2) mixing the thermal addition reaction product with a free radical initiator to perform a further addition reaction. The method is simple in process, has few side reactions, and can prepare polyisobutenyl succinic anhydride with high viscosity and good quality; when the polyisobutenyl succinic anhydride is used in the preparation of a mono-polyisobutenyl succinimide ashless dispersant, the dispersant has better dispersing performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of polymer synthesis, in particular to a method for preparing polyisobutenyl succinic anhydride and a method for preparing mono-polyisobutenyl succinimide. BACKGROUND

[0002] Polyisobutenyl succinic anhydride is an intermediate for synthesizing mono-polyisobutenyl succinimide ashless dispersant, an important component of lubricating oil. The existing preparation methods include chlorination method, thermal addition method and free radical method.

[0003] The chlorination method is to react chlorine with polyisobutene, and then connect the chlorination product with maleic anhydride. US3231587 and US3912764 disclose a method for preparing polyisobutenyl succinic anhydride by chlorination process, which makes polyisobutene and maleic anhydride undergo alkylation reaction under the action of chlorine. Due to the introduction of chlorine, the product inevitably contains chlorine, which does not meet the environmental protection requirements.

[0004] The thermal addition method is to directly add high-activity polyisobutene and maleic anhydride to perform thermal addition reaction. Since only α-double bond in high-activity polyisobutene is easy to participate in the reaction, the content of α-double bond in high-activity polyisobutene is required to be high, and high temperature is needed to promote the thermal addition reaction. If not properly controlled, it is easy to produce glue and other by-products. CN1315317A discloses a method for preparing alkenyl succinic anhydride, which is to make polyisobutene with an end alkene content of more than 65% and maleic anhydride undergo alkylation reaction at a temperature of 200-250°C for 6-10h at a molar ratio of 1:1.2-1.8. In addition, US4388471 discloses a method for preparing polyisobutenyl succinic anhydride by thermal addition process. Although the process is simple, the reaction period is long, and the conversion rate of polyisobutene is low.

[0005] The free radical method is to introduce a free radical initiator to make polyisobutene and maleic anhydride undergo free radical reaction, but it can initiate the self-polymerization of excess maleic anhydride and polyisobutene or the crosslinking reaction between the two, which is easy to cause the viscosity to increase sharply, even to climb the pole phenomenon, and has certain technical disadvantages. CN1088218A discloses a process for preparing polyisobutenyl succinic anhydride by oxidizing polyisobutene and then initiating hydrolysis by free radicals. Since the method needs to perform oxidation reaction of polyisobutene before hydrolysis reaction, the preparation process is complicated, and due to the oxidation reaction, the product structure is complex, the product color is dark, and the glue increases, which seriously affects the product quality. SUMMARY

[0006] The present application aims to overcome the above-mentioned problems existing in the prior art, and provide a method for preparing polyisobutenyl succinic anhydride and a method for preparing mono-polyisobutenyl succinimide, which has simple process, less side reactions, and can prepare polyisobutenyl succinic anhydride with high viscosity and good quality, and when used in the preparation of mono-polyisobutenyl succinimide ashless dispersant, the dispersant has better dispersing performance.

[0007] In order to achieve the above-mentioned purpose, the present application provides a method for preparing polyisobutenyl succinic anhydride, which comprises the following two steps under the protection of inert atmosphere:

[0008] (1) mixing polyisobutene with an α-double bond content of ≥75% with maleic anhydride to perform thermal addition reaction to obtain a thermal addition reaction product;

[0009] The molar ratio of the polyisobutene to the maleic anhydride is 1:1-1.6.

[0010] (2) mixing the thermal addition reaction product with a free radical initiator to perform further hydrocarbonization reaction.

[0011] The present application provides a method for preparing mono-polyisobutenyl succinimide, which comprises preparing polyisobutenyl succinic anhydride by the above-mentioned method, and then contacting the obtained polyisobutenyl succinic anhydride with a polyene polyamine to perform amination reaction.

[0012] Through the above technical solution, the present application can achieve the following beneficial effects:

[0013] 1. The present application can prepare polyisobutenyl succinic anhydride with high viscosity and good quality, and has less side reactions, so that the generation of complex products with much gel and dark color can be avoided. The polyisobutenyl succinic anhydride prepared by the method of the present application has better dispersing performance when used in the preparation of mono-polyisobutenyl succinimide ashless dispersant.

[0014] 2. The method of the present application can add maleic anhydride in one step, and obtain polyisobutenyl succinic anhydride with high viscosity under the condition of low maleic anhydride dosage, and does not need to be purged after thermal addition, thus simplifying the process. DETAILED DESCRIPTION

[0015] The endpoints of the ranges and any values disclosed herein are not limited to the precise values recited as the exact dimensions are not considered critical for the purposes of the application. The ranges should be interpreted as being inclusive of the recited values. For values having been expressed as a range, the endpoints of the ranges are inclusive and independently combinable with each other, with the single values, and with other ranges to generate new ranges having the same minimum and maximum values as the original ranges and values. Such new ranges are also specifically disclosed herein.

[0016] In a first aspect, the present application provides a method for preparing polyisobutenyl succinic anhydride, which comprises carrying out the following two steps under the protection of inert atmosphere:

[0017] (1) mixing polyisobutene with an α-double bond content of ≥75% with maleic anhydride to carry out thermal addition reaction, to obtain a thermal addition reaction product;

[0018] wherein the molar ratio of polyisobutene to maleic anhydride is 1:1-1.6;

[0019] (2) mixing the thermal addition reaction product with a free radical initiator to carry out further addition reaction.

[0020] wherein the polyisobutene comprises polyisobutene with α-double bond and polyisobutene with β-double bond, and the "α-double bond content" refers to the percentage of polyisobutene with α-double bond in the total molar amount of polyisobutene.

[0021] wherein the inert atmosphere is not particularly limited as long as it does not participate in the above-mentioned reaction, and preferably, the inert atmosphere is provided by nitrogen and / or inert gas.

[0022] According to the present application, in order to further improve the viscosity of the product, preferably, the number average molecular weight of the polyisobutene is 800-2500 g / mol (for example, it can be 800 g / mol, 1000 g / mol, 1200 g / mol, 1500 g / mol, 1800 g / mol, 2000 g / mol, 2200 g / mol, 2300 g / mol, 2500 g / mol), and more preferably 1000-2300 g / mol.

[0023] According to the present application, in order to further improve the viscosity of the product, preferably, the molar ratio of the polyisobutene to maleic anhydride is 1:1-1.5 (for example, it can be 1:1, 1:2, 1:3, 1:4, 1:5).

[0024] It can be understood that the higher the number average molecular weight of polyisobutene, the higher the proportion of maleic anhydride generally needs to be, but when the number average molecular weight of polyisobutene and the molar ratio of polyisobutene to maleic anhydride meet the requirements as described above, polyisobutenyl succinic anhydride with higher viscosity can be obtained.

[0025] According to the present application, preferably, the conditions of the thermal addition hydrocarbonylation reaction include: temperature of 180-250℃ (for example, can be 180℃, 200℃, 210℃, 220℃, 230℃, 250℃), time of 2-8h (for example, can be 2h, 3h, 4h, 5h, 6h, 7h, 8h); more preferably, the conditions of the thermal addition hydrocarbonylation reaction include: temperature of 200-230℃, time of 4-6h. The inventors of the present application found in the research that when the range as described above is met, not only the conversion rate of the thermal addition hydrocarbonylation reaction can be improved, but also the by-product reaction can be reduced, the content of gum in the product can be reduced, and the color of the product can be avoided from becoming darker.

[0026] According to the present application, preferably, the amount of the free radical initiator is 0.2-8wt% (0.2wt%, 0.5wt%, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%) of the amount of the polyisobutylene, more preferably 0.5-5wt%.

[0027] According to the present application, preferably, the free radical initiator is at least one selected from alkyl peroxide, ester peroxide and acyl peroxide, more preferably at least one selected from di-tert-butyl peroxide, tert-butyl peroxybenzoate and benzoyl peroxide.

[0028] The inventors of the present application found in the research that in step (1), the polyisobutylene with α-double bond is easy to undergo thermal addition hydrocarbonylation reaction to generate polyisobutylene-based succinic anhydride, and the polyisobutylene also includes polyisobutylene with β-double bond, which has lower activity and is difficult to participate in the thermal addition hydrocarbonylation reaction. In step (2), the free radical initiator can promote the polyisobutylene with β-double bond to react with maleic anhydride, and further improve the viscosity of the product. The amount of the free radical initiator can be adjusted according to the type of the free radical initiator, but when the amount and type range as described above are met, the viscosity of the product can be further improved.

[0029] According to the present application, the mixing method in step (2) is that the free radical initiator is added into the thermal addition hydrocarbonylation reaction product within 0.5-3h at 100-200℃, and then the reaction is continued for 1-3h at 140-200℃. It can be understood that the temperature of the thermal addition hydrocarbonylation reaction is relatively high, so the thermal addition hydrocarbonylation reaction product can be first cooled to 100-200℃, then the free radical initiator is added, and then the temperature can be increased and the reaction can be carried out.

[0030] According to the present application, preferably, the method does not include the step of removing unreacted maleic anhydride. As described above, the inventors of the present application found in the research that adding a free radical initiator to the thermal addition hydrocarbon reaction product can promote the reaction of the polyisobutylene with β-double bond and maleic anhydride, make full use of the maleic anhydride, and further improve the viscosity of the product. Using the method as described above, not only the unreacted maleic anhydride is removed by purging, making the process simpler, but also the viscosity of the product is further improved.

[0031] According to the present application, preferably, the step (2) does not include the operation of introducing maleic anhydride. Using the method of the present application, the maleic anhydride can be added in step (1) only, which is simple in operation and lower in the amount of maleic anhydride used.

[0032] In a second aspect, the present application provides a method for preparing a mono-polyisobutylene succinimide, which comprises preparing a polyisobutylene-based succinic anhydride according to the method as described above, and then contacting the obtained polyisobutylene-based succinic anhydride with a polyene polyamine to perform an amination reaction.

[0033] According to a particularly preferred embodiment of the present application, the polyisobutylene-based succinic anhydride is prepared according to the following method:

[0034] (1) The polyisobutylene with an α-double bond content of ≥75% and a number average molecular weight of 1500-2300 g / mol is added to a stirred reaction kettle, and after being replaced by nitrogen, maleic anhydride is added at a molar ratio of polyisobutylene to maleic anhydride of 1:1.4-1.5. After being heated to 225-230°C and reacted for 5.5-6 h, a thermal addition reaction product is obtained.

[0035] (2) The thermal addition reaction product is cooled to 100-110°C, and benzoyl peroxide is added dropwise within 2-3 h, the amount of benzoyl peroxide being 4-5% by weight of the amount of polyisobutylene, and then the temperature is raised to 140-150°C and the reaction is continued for 2.5-3 h to obtain a polyisobutylene-based succinic anhydride.

[0036] The present application will be described in detail below by way of examples. In the following examples,

[0037] The polyisobutylene is purchased from Yangzi BASF Co., Ltd.

[0038] The method for measuring the kinematic viscosity of the polyisobutylene-based succinic anhydride at 100°C is performed according to the method in GB / T265;

[0039] The method for preparing the mono-polyisobutenyl succinimide from the polyisobutenyl succinic anhydride is to mix the polyisobutenyl succinic anhydride and tetraethylenepentamine at a molar ratio of 1:0.9, and the polyisobutenyl succinic anhydride and dilution oil 150SN at a weight ratio of 1:1, then heat from 60°C, and gradually increase the temperature to 130°C within 4h, and dehydrate at 140°C under vacuum until no obvious water vapor is generated to obtain the final product.

[0040] The test method for the dispersing property of the mono-polyisobutenyl succinimide is the spot test, which is one of the commonly used dispersing property test methods, and is mainly used to simulate the dispersing property of the oil sludge at low temperature. The specific test is as follows: 10g of carbon black is added into 90g of 500SN base oil, and is uniformly ground into an oil paste by using a colloid mill. In the test, 20g of the test oil is mixed with 1g of the oil paste, and is uniformly stirred by using a high-speed stirrer and ultrasonic oscillation. Then, the oil sample is placed in a 50°C constant temperature bath for 6h, and then is dropped on filter paper at 50°C for 24h. The diameter (d) of the diffusion circle and the diameter (D) of the oil circle are measured, and the ratio γ = d / D is taken as the parameter index of the dispersing property. The larger the γ value is, the better the dispersing property of the oil is. The oil spot represents the carbon black that cannot be dispersed, and the dispersion circle represents the dispersing property of the oil.

[0041] Example 1

[0042] (1) 100g of polyisobutylene with an α-double bond content of ≥75% and a number average molecular weight of 1000g / mol is added into a reaction kettle with stirring, and after nitrogen replacement, 9.8g of maleic anhydride is added at a molar ratio of polyisobutylene to maleic anhydride of 1:1. The reaction kettle is heated to 200°C, and the thermal addition reaction product is obtained after 4h of reaction.

[0043] (2) The thermal addition reaction product is cooled to 120°C, and 0.5g of di-tert-butyl peroxide is added dropwise within 0.5h. Then, the temperature is increased to 160°C, and the polyisobutenyl succinic anhydride is obtained after 3h of continuous reaction.

[0044] The kinematic viscosity at 100°C of the obtained product is measured, and the polyisobutenyl succinic anhydride is used to prepare mono-polyisobutenyl succinimide. The dispersing property of the mono-polyisobutenyl succinimide is tested, and the results are shown in Table 1.

[0045] Example 2

[0046] (1) 100g of polyisobutylene with an α-double bond content of ≥75% and a number average molecular weight of 1300g / mol is added into a reaction kettle with stirring, and after nitrogen replacement, 9.8g of maleic anhydride is added at a molar ratio of polyisobutylene to maleic anhydride of 1:1.3. The reaction kettle is heated to 220°C, and the thermal addition reaction product is obtained after 5h of reaction.

[0047] (2) The thermal addition reaction product was cooled to 150°C, 2.5 g of t-butyl peroxybenzoate was added dropwise within 1.5 h, and then the temperature was raised to 200°C and the reaction was continued for 0.5 h to obtain polyisobutenyl succinic anhydride.

[0048] The 100°C kinematic viscosity of the product was measured, and the polyisobutenyl succinic anhydride obtained was used to prepare mono-polyisobutenyl succinimide. The dispersing performance of the mono-polyisobutenyl succinimide was tested, and the results are shown in Table 1.

[0049] Example 3

[0050] (1) 100 g of polyisobutylene with an α-double bond content of ≥75% and a number average molecular weight of 2300 g / mol was added to a stirred reaction kettle, which was replaced with nitrogen, and 6.4 g of maleic anhydride was added at a molar ratio of polyisobutylene to maleic anhydride of 1:1.5. After heating to 230°C and reacting for 6 h, a thermal addition reaction product was obtained.

[0051] (2) The thermal addition reaction product was cooled to 100°C, 5 g of benzoyl peroxide was added dropwise within 3 h, and then the temperature was raised to 140°C and the reaction was continued for 3 h to obtain polyisobutenyl succinic anhydride.

[0052] The 100°C kinematic viscosity of the product was measured, and the polyisobutenyl succinic anhydride obtained was used to prepare mono-polyisobutenyl succinimide. The dispersing performance of the mono-polyisobutenyl succinimide was tested, and the results are shown in Table 1.

[0053] Comparative Example 1

[0054] 100 g of polyisobutylene with an α-double bond content of ≥75% and a number average molecular weight of 1000 g / mol was added to a stirred reaction kettle, which was replaced with nitrogen, and 9.8 g of maleic anhydride was added at a molar ratio of polyisobutylene to maleic anhydride of 1:1. The temperature was raised to 120°C, 5 g of di-t-butyl peroxide was added dropwise within 2 h, and then the temperature was raised to 160°C and the reaction was continued. The viscosity increased rapidly for a short time after 1 h of reaction, and a climbing rod phenomenon occurred.

[0055] The 100°C kinematic viscosity of the product was measured, and the polyisobutenyl succinic anhydride obtained was used to prepare mono-polyisobutenyl succinimide. The dispersing performance of the mono-polyisobutenyl succinimide was tested, and the results are shown in Table 1.

[0056] Comparative Example 2

[0057] 100 g of polyisobutylene with an α-double bond content of ≥75% and a number average molecular weight of 1000 g / mol was added to a stirred reaction kettle, which was replaced with nitrogen, and 9.8 g of maleic anhydride was added at a molar ratio of polyisobutylene to maleic anhydride of 1:1. The temperature was raised to 120°C, 5 g of di-t-butyl peroxide was added dropwise within 2 h, and then the temperature was raised to 160°C and the reaction was continued. The viscosity increased rapidly for a short time after 1 h of reaction, and a climbing rod phenomenon occurred.

[0058] Comparative Example 3

[0059] Into a stirred reaction vessel, 150 g of polyisobutylene with an α-double bond content of ≥ 75% and a number average molecular weight of 1000 g / mol was introduced, after being replaced by nitrogen, and heated to 190°C, then maleic anhydride was added at a molar ratio of polyisobutylene to maleic anhydride of 1:1. After dropwise addition, the temperature was lowered to 150°C, and then maleic anhydride was slowly added (molar ratio of polyisobutylene to maleic anhydride of 1:0.4), while dropwise adding di-tert-butyl peroxide (amount of 1.46% by weight of polyisobutylene), and the dropwise addition was completed in 2 h, then the reaction was continued at 150°C for 4 h, to obtain polyisobutylene-based succinic anhydride.

[0060] The 100°C kinematic viscosity of the obtained product was measured, and the obtained polyisobutylene-based succinic anhydride was used to prepare mono-polyisobutylene succinimide, and the dispersing performance of the mono-polyisobutylene succinimide was tested, and the results are listed in Table 1.

[0061] Comparative Example 4

[0062] The polyisobutylene-based succinic anhydride was prepared according to the method of Example 2, except that in step (1), maleic anhydride was added at a molar ratio of polyisobutylene to maleic anhydride of 1:1; and in step (2), maleic anhydride was added at a molar ratio of polyisobutylene to maleic anhydride of 1:0.3, while adding tert-butyl peroxybenzoate.

[0063] The 100°C kinematic viscosity of the obtained product was measured, and the obtained polyisobutylene-based succinic anhydride was used to prepare mono-polyisobutylene succinimide, and the dispersing performance of the mono-polyisobutylene succinimide was tested, and the results are listed in Table 1.

[0064] Table 1

[0065] Example No. 100 cSt @ 100°C 2 / s)]]> gamma Example 1 735 0.85 Example 2 1389 0.86 Example 3 3046 0.89 Comparative Example 1 584 0.77 Comparative Example 2 Crawling occurred, so it could not be measured - Comparative Example 3 ＜680 0.78 Comparative Example 4 ＜1200 0.80

[0066] wherein the 100°C kinematic viscosity (mm 2 / s) refers to the properties of the polyisobutylene-based succinic anhydride, and the γ value reflects the dispersing performance of the mono-polyisobutylene succinimide.

[0067] As can be seen from the results of Table 1, the polyisobutenyl succinic anhydride with high viscosity can be obtained by using the technical solutions of Examples 1-3 of the present application, and the monoisobutenyl succinimide prepared by using the polyisobutenyl succinic anhydride has better dispersing performance. The comparative examples have poor effects, especially Comparative Example 2, which has a sharp increase in viscosity during the preparation process, and a pole-climbing phenomenon occurs, so that the viscosity cannot be measured. Moreover, the polyisobutenyl succinic anhydride prepared by Examples 1-3 does not need to be treated by blowing off free maleic anhydride, and the product has light color, less maleic anhydride polycondensation byproduct, less gum, and high product quality.

[0068] The preferred embodiments of the present application are described in detail above, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the present application and belong to the protection scope of the present application.

Claims

1. A process for the preparation of polyisobutenyl succinic anhydride characterized in that, The method comprises two steps as follows under protection of inert atmosphere: (1) mixing polyisobutylene with an alpha-double bond content of ≥75% with maleic anhydride to perform a thermal addition reaction to obtain a thermal addition reaction product; wherein the molar ratio of the polyisobutylene to the maleic anhydride is 1:1-1.6; the number average molecular weight of the polyisobutylene is 800-2500 g / mol; the thermal addition reaction conditions include: temperature of 180-250℃, time of 2-8h; (2) mixing the thermal addition reaction product with a free radical initiator to perform a further addition reaction; wherein step (2) does not include the operation of introducing maleic anhydride; the amount of the free radical initiator is 0.2-8% by weight of the amount of the polyisobutylene; the mixing mode is: the free radical initiator is added into the thermal addition reaction product within 0.5-3h at 100-200℃, and then the reaction is continued at 140-200℃ for 1-3h.

2. The method of claim 1, wherein, The number average molecular weight of the polyisobutylene is 1000-2300 g / mol.

3. The method of claim 1 or 2, wherein, The molar ratio of the polyisobutylene to the maleic anhydride is 1:1-1.

5.

4. The method of claim 1, wherein, The thermal addition reaction conditions include: temperature of 200-230℃, time of 4-6h.

5. The method of claim 1, wherein, The amount of the free radical initiator is 0.5-5% by weight of the amount of the polyisobutylene.

6. The method of claim 1, wherein, The free radical initiator is selected from at least one of alkyl peroxides, ester peroxides and acyl peroxides.

7. The method of claim 6, wherein, The free radical initiator is selected from at least one of di-tert-butyl peroxide, tert-butyl peroxybenzoate and benzoyl peroxide.

8. The method of claim 1, wherein, The method does not include a step of removing unreacted maleic anhydride.

9. A process for the preparation of a monomeric isobutene succinimide, characterized in that, The method comprises preparing polyisobutylene-based succinic anhydride according to the method of any one of claims 1-8, and then contacting the obtained polyisobutylene-based succinic anhydride with a polyene polyamine to perform an amination reaction.