An oil-soluble iron adsorbent, its synthesis method and application

Abstract

This invention discloses an oil-soluble iron adsorbent, its synthesis method, and its application. The method involves terminal-amino grouping of a long-chain compound, polybutadiene, to obtain an amino grouped polybutadiene compound. This compound then reacts with carbon disulfide to generate a high-molecular-weight polymer containing dithiocarbamate groups, with the amino grouped polybutadiene compound as the main component. This surface-modified adsorbent, without affecting the original adsorbent performance, introduces a long-chain compound with dithiocarbamate groups, which can complex with oil-soluble iron in lubricating oil to form chelated iron. This chelated iron precipitates from the lubricating oil and accumulates on the adsorbent surface, thereby achieving the purpose of removing oil-soluble iron. Furthermore, surface modification of the adsorbent involves acidification treatment to introduce carboxyl groups onto the adsorbent surface. Simultaneously, the reaction between these surface carboxyl groups and the long-chain compound allows the long-chain compound to exhibit its chemical properties, effectively improving the adsorption rate of the adsorbent for polar aging products.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of lubricating oil metal content exceeding standard treatment, and particularly relates to an oil-soluble iron adsorbent and a synthesis method and application thereof. BACKGROUND

[0002] The metal element exceeding standard in the lubricating oil is mainly iron element, and the iron element mainly comes from the wear of the gear box during operation. The iron element is initially iron particles, which gradually reacts with the moisture in the oil, the aged products and the like under the action of temperature and gear shearing force to form iron elements in different states after entering the lubricating oil. A part of the iron enters the lubricating oil in the form of ions to form oil-soluble iron in the oil, which has certain catalytic, acidic, non-biodegradable and enriching properties. The oil-soluble iron is an organic iron compound in a dissolved state in the oil. The oil-soluble iron can accelerate the oxidation of the lubricating oil, increase the acid value of the oil, and easily generate sludge, paint film and acidic substances after the oxidation of the lubricating oil, which can cause damage to the gear surface.

[0003] The existing lubricating oil purification method mainly removes various pollutants in the oil through the filtering mode of the adsorbent. The ferromagnetic particles can be removed through the magnetic filter, and the remaining pollutants can be removed through the adsorption of the adsorbent. However, the adsorbent is non-selective adsorption, and the oil-soluble iron cannot be removed through the physical filtering mode because it is completely dissolved in the oil. Therefore, the generation and enrichment of the iron element will cause the iron content of the gear oil to exceed the standard, which seriously threatens the operation safety of the lubricating oil system. SUMMARY

[0004] The purpose of the present application is to overcome the shortcomings of the prior art, and to provide an oil-soluble iron adsorbent and a synthesis method and application thereof to solve the problem that the oil-soluble iron in the lubricating oil is difficult to remove through the physical filtering mode, which causes the iron content of the gear oil to exceed the standard and threatens the operation of the lubricating oil system.

[0005] To achieve the above purpose, the following technical solutions are adopted in the present application:

[0006] A synthesis method of an oil-soluble iron adsorbent, in which dithiocarbamate-terminated polybutadiene is mixed with an adsorbent with carboxyl groups, and a condensation reaction occurs under the action of acyl chloride to generate an oil-soluble iron adsorbent;

[0007] The preparation process of the dithiocarbamate-terminated polybutadiene is as follows: after the dithiocarbamate-terminated polybutadiene and dichloromethane are mixed, an alkaline solution is added, then carbon disulfide is added, and after the reaction is completed, the reaction product is washed and dried to obtain the dithiocarbamate-terminated polybutadiene;

[0008] The preparation process of the terminal amine group polybutadiene is as follows: the terminal hydroxyl group polybutadiene is dissolved in dichloromethane with 2-naphthalenesulfonyl chloride, pyridine-dichloromethane solution is added, and the terminal acyl polybutadiene compound is obtained after reaction; the terminal acyl polybutadiene compound is dissolved in N,N-dimethylformamide with sodium azide, and the terminal azide group polybutadiene is obtained after reaction; the terminal azide group polybutadiene is dissolved in anhydrous tetrahydrofuran with N,N-dimethylamino borohydride lithium, and the terminal amine group polybutadiene is obtained after reaction.

[0009] The further improvement of the present application is:

[0010] Preferably, the mixing molar ratio of the dithio-carbamate-terminated amine group polybutadiene and the carboxyl group-containing adsorbent is 1:1.2-1.5.

[0011] Preferably, the preparation process of the carboxyl group-containing adsorbent is as follows: the adsorbent is added into an acid liquid mixture, the mass fraction of the adsorbent in the mixture is 10-15%, reflux reaction is carried out at 100-140 ℃ for 8 h, and the product is cleaned and dried after the reaction system is cooled, so as to obtain the carboxyl group-containing adsorbent.

[0012] Preferably, the adsorbent is activated clay, kaolin, activated carbon or functional active carbon fiber.

[0013] Preferably, the mixing mass ratio of the terminal amine group polybutadiene and dichloromethane is 1:5, the added amount of the alkaline solution is equal to the volume of the mixed solution of the terminal amine group polybutadiene and dichloromethane, and the added amount of carbon disulfide is 0.2-0.4 times the molar amount of the terminal amine group polybutadiene.

[0014] Preferably, the reaction temperature of the preparation process of the dithio-carbamate-terminated amine group polybutadiene is 5-30 ℃, and the reaction time is 3 h.

[0015] Preferably, the mixing molar ratio of the terminal hydroxyl group polybutadiene and 2-naphthalenesulfonyl chloride is 1:1.2-1.5; the mixing molar ratio of the terminal acyl polybutadiene compound and sodium azide is 1:1.2-1.5; and the mixing molar ratio of the terminal azide group polybutadiene and N,N-dimethylamino borohydride lithium is 1:1.2.

[0016] Preferably, the reaction temperature of the terminal hydroxyl group polybutadiene and 2-naphthalenesulfonyl chloride is 35-40 ℃, and the reaction time is 30 h; the reaction temperature of the terminal acyl polybutadiene compound and sodium azide is 40-60 ℃, and the reaction time is 15 h; and the reaction temperature of the terminal azide group polybutadiene and N,N-dimethylamino borohydride lithium is 40 ℃, and the reaction time is 30 h.

[0017] An oil-soluble iron adsorbent obtained by any one of the above synthesis methods, wherein the adsorbent is connected with dithio-carbamate-terminated amine group polybutadiene through a carboxyl group.

[0018] Use of the oil-soluble iron adsorbent as described above in adsorbing oil-soluble iron.

[0019] Compared with the prior art, the application has the following beneficial effects:

[0020] The application discloses a synthesis method of an oil-soluble iron adsorbent.

[0021] The surface modification adsorbent does not affect the original adsorbent performance, and can be combined with oil-soluble iron in lubricating oil by introducing a long-chain compound with a dithioformic acid group (-CSS-), so as to generate chelated iron, precipitate from the lubricating oil, and enrich on the surface of the adsorbent, thereby achieving the purpose of removing oil-soluble iron. The surface of the adsorbent is modified by acidizing treatment, carboxyl groups are introduced on the surface of the adsorbent, the introduced carboxyl groups not only change the polarity of the adsorbent to some extent, but also can obtain the chemical properties of the long-chain compound through the reaction of the surface carboxyl groups with the long-chain compound, so that the adsorption rate of the adsorbent to polar aging products can be effectively improved. The iron element chelating agent on the surface of the adsorbent is combined with oil-soluble iron, so that the oil-soluble iron is precipitated from the lubricating oil, and the purpose of removing the oil-soluble iron is achieved.

[0022] DETAILED DESCRIPTION

[0023] The application discloses a synthesis method of an oil-soluble iron adsorbent.

[0024] The terminal hydroxyl polybutadiene is sequentially reacted with 2-naphthalenesulfonyl chloride, sodium azide and N, N-dimethylaminoborohydride lithium to prepare the terminal amine polybutadiene.

[0025] The specific reaction is as follows:

[0026] Step 1.1, dissolve the hydroxyl-terminated polybutadiene and 2-naphthalenesulfonyl chloride in dichloromethane, the molar ratio of hydroxyl-terminated polybutadiene and 2-naphthalenesulfonyl chloride is 1:1.2-1.5; 79g pyridine is dissolved in 298mL dichloromethane to prepare a 20% pyridine-dichloromethane solution, and 1 drop of pyridine is added per second through a constant pressure dropping funnel, wherein the molar ratio of hydroxyl-terminated polybutadiene and pyridine is 1:1; the reaction is carried out at 35-40°C under argon protection for 30h to prepare the acyl-terminated polybutadiene compound, and the reaction product is washed with ethanol and dried.

[0027] Step 1.2, dissolve the acyl-terminated polybutadiene compound and sodium azide in N,N-dimethylformamide according to a molar ratio of 1:1.2-1.5, and react at 40-60°C under argon protection for 15h to produce azido-terminated polybutadiene, which is washed with ethanol and dried to obtain azido-terminated polybutadiene.

[0028] Step 1.3, dissolve the azido-terminated polybutadiene and lithium borohydride in anhydrous tetrahydrofuran according to a molar ratio of 1:1.2, and react at 40°C under argon protection for 30h to obtain amine-terminated polybutadiene, which is washed with ethanol and dried.

[0029] The reaction process is as follows:

[0030]

[0031] Step 2, dithiocarbamate saltification of amine-terminated polybutadiene

[0032] Dissolve the amine-terminated polybutadiene and dichloromethane according to a mass ratio of 1:5 to prepare a solution, add an alkaline solution with the same volume as the above solution at a temperature of 5-30°C, and add carbon disulfide at a rate of not more than 5% of the volume of carbon disulfide per minute, which is 0.2-0.4 times the amount of amine-terminated polybutadiene, to prevent organic volatilization, maintain the temperature at 5-30°C, and continue to react for 3h, when a large amount of precipitate is generated at the bottom of the solution until no more precipitate is generated. The reaction product is filtered, washed with distilled water and methanol in turn, and dried under vacuum at 60°C for at least 8h to obtain the dithiocarbamate saltified amine-terminated polybutadiene.

[0033] Specifically, carbon disulfide should be added after the reaction of amine-terminated polybutadiene is completed, otherwise the amount of amine-terminated polybutadiene generated will be small, affecting the use effect of the final product.

[0034] Preferably, the alkaline conditions required for the reaction can be achieved by adding 15% ammonia water or 7% NaOH aqueous solution to the amine-terminated polybutadiene solution.

[0035]

[0036] Step 3, surface acidification of adsorbent

[0037] The adsorbent is added into the acid mixture of concentrated nitric acid and concentrated sulfuric acid with a volume ratio of 1:3 at a mass fraction of 10-15%, and refluxed at 100-140℃ for 8h. After cooling, the mixture is washed with deionized water until neutral, and then vacuum dried until completely dry, to obtain the adsorbent with carboxyl groups (-COOH) on the surface.

[0038] Preferably, the adsorbent can be activated clay, kaolin, activated carbon, functional activated carbon fiber, etc.

[0039] Step 4, synthesis of modified adsorbent

[0040] The dithio-carbamate-terminated polybutadiene amine is condensed with the adsorbent with carboxyl groups (-COOH) under the action of a dehydrating agent (dichlorosulfoxide or DCC) at a molar ratio of 1:1.2-1.5. The molar ratio of the dehydrating agent to the dithio-carbamate-terminated polybutadiene amine is 1:1. When the dehydrating agent is DCC, the dehydration reaction is generally carried out at 0-25℃ for 24-72h. When the dehydrating agent is dichlorosulfoxide, the ice water bath is added dropwise, and after the dropwise addition is completed, the reaction is carried out at 50-70℃ for 4h, to generate the modified adsorbent which can be complexed with oil-soluble iron.

[0041]

[0042] wherein R is the adsorbent.

[0043] The second aspect of the present application also discloses an oil-soluble iron adsorbent, which has dithio-carbamate-terminated polybutadiene amine connected to a common adsorbent through a carboxyl group, so that the dithio-carboxyl group (-CSS-) can be complexed with oil-soluble iron to generate an iron element chelate, and the adsorbed iron element can be fixed on the adsorbent and cannot be suspended in the oil, so that the oil does not need to be filtered to remove the chelate product.

[0044] The second aspect of the present application also discloses an application of the oil-soluble iron adsorbent. It is found through the application that the oil-soluble iron content in general poor oil is between 70-300ppm. The modified adsorbent prepared above is used to make a filter element, and the running lubricating oil with high iron content is treated by the filter element. After equivalent filtration for more than 3 times, the oil-soluble iron content in the oil can be reduced to below 20ppm.

[0045] Example 1

[0046] Step 1, hydroxyl-terminated polybutadiene amination

[0047] The terminal hydroxyl polybutadiene is reacted with 2-naphthalenesulfonyl chloride, sodium azide and lithium borohydride to prepare terminal amine polybutadiene.

[0048] The specific reaction is as follows:

[0049] 500g of terminal hydroxyl polybutadiene is dissolved in 271g of 2-naphthalenesulfonyl chloride in dichloromethane, the molar ratio of terminal hydroxyl polybutadiene to acyl chloride compound is 1:1.2, pyridine is used as nucleophilic catalyst and acid binding agent, 79g of pyridine is dissolved in 298mL of dichloromethane to prepare a 20% pyridine-dichloromethane solution, which is added dropwise through a constant pressure dropping funnel at a rate of 1 drop / s, the molar ratio of terminal hydroxyl polybutadiene to pyridine is 1:1, the reaction is carried out at 35°C under argon protection for 30h to prepare terminal acyl polybutadiene compound, and the reaction product is washed with ethanol and dried.

[0050] 500g of terminal acyl polybutadiene compound is dissolved in 78g of sodium azide in N,N-dimethylformamide according to a molar ratio of 1:1.2, the reaction is carried out at 40°C under argon protection for 15h to produce terminal azide polybutadiene, and the product is washed with ethanol and dried.

[0051] 500g of terminal azide polybutadiene is dissolved in 78g of N,N-dimethylamino borohydride in anhydrous tetrahydrofuran according to a molar ratio of 1:1.2, the reaction is carried out at 40°C under argon protection for 30h to obtain terminal amine polybutadiene, and the product is washed with ethanol and dried.

[0052] Step 2, dithiocarbamate of terminal amine polybutadiene

[0053] Terminal amine polybutadiene and dichloromethane are prepared into a solution according to a mass ratio of 1:5, at a temperature of 20°C, an equal volume of the above solution is added to 15% ammonia water, and carbon disulfide is added at a rate of not more than 5% of the volume of carbon disulfide per minute, 0.2 times the amount of terminal amine polybutadiene, the temperature is maintained at 20°C, and the reaction is continued for 3h, when a large amount of precipitate is generated at the bottom of the solution until no more precipitate is generated, the reaction is completed. The reaction product is suction filtered, washed with distilled water and methanol in sequence, and vacuum dried at 60°C for at least 8h to obtain the dithiocarbamate of terminal amine polybutadiene.

[0054] Step 3, surface acidification of adsorbent

[0055] A mixture of concentrated nitric acid and concentrated sulfuric acid is prepared according to a volume ratio of 1:3, activated clay is added to the acid mixture according to a mass ratio of 15%, refluxed at 120°C for 8h, washed with deionized water until neutral after cooling, and then vacuum dried until completely dry. The adsorbent with carboxyl groups (-COOH) on the surface is obtained.

[0056] Step 4, synthesis of modified adsorbent

[0057] The dithiocarbamate-terminated polybutadiene amine with a molar ratio of 1:1.2 is condensed with activated clay with carboxyl (-COOH) under the action of dichlorosulfoxide dehydrating agent, the reaction temperature is 60°C, and the reaction time is 4h, to generate a modified adsorbent capable of complexing with oil-soluble iron.

[0058] The filter cartridge prepared by using the modified adsorbent prepared above is used to cyclically treat the lubricating oil with an iron content of 120ppm in a wind power plant, and the oil-soluble iron content in the oil can be reduced to 8ppm after equivalent filtration for 3 times.

[0059] Example 2

[0060] Step 1: hydroxyl-terminated polybutadiene amination

[0061] 500g of hydroxyl-terminated polybutadiene is dissolved in dichloromethane with 339g of 2-naphthalenesulfonyl chloride, the molar ratio of hydroxyl-terminated polybutadiene to acyl chloride compound is 1:1.5, 79g of pyridine is dissolved in 298mL of dichloromethane to prepare a pyridine-dichloromethane solution with a mass fraction of 20%, which is added dropwise through a constant-pressure dropping funnel at a rate of 1 drop / s, the molar ratio of hydroxyl-terminated polybutadiene to pyridine is 1:1, and the reaction is carried out at 40°C under argon protection for 30h to prepare an acyl-terminated polybutadiene compound, and the reaction product is washed with ethanol and dried.

[0062] 500g of acyl-terminated polybutadiene compound is dissolved in N,N-dimethylformamide with 97.5g of sodium azide according to a molar ratio of 1:1.5, and the reaction is carried out at 60°C under argon protection for 15h to generate azido-terminated polybutadiene, and the product is washed with ethanol and dried.

[0063] 500g of azido-terminated polybutadiene, 97.5g of N,N-dimethylaminoborohydride lithium, are dissolved in anhydrous tetrahydrofuran according to a molar ratio of 1:1.5, and the reaction is carried out at 50°C under argon protection for 30h to obtain amine-terminated polybutadiene, and the product is washed with ethanol and dried.

[0064] Step 2, dithiocarbamate-terminated polybutadiene amine

[0065] The terminal amine group polybutadiene and dichloromethane are prepared into a solution with a mass ratio of 1:5, at a temperature of 30°C, an equal volume of 7% NaOH aqueous solution is added to the above solution, and carbon disulfide is added at a rate of not more than 5% of the volume of carbon disulfide per minute, 0.4 times the amount of substance of the terminal amine group polybutadiene, the temperature is kept at 30°C and the reaction continues for 3h, when a large amount of precipitate is generated at the bottom of the solution until no more precipitate is generated, the reaction is completed. The reaction product is suction filtered, washed with distilled water and methanol in turn, and vacuum dried at 60°C for at least 8h, and the obtained product is the dithiocarbamate salt of the terminal amine group polybutadiene.

[0066] Step 3, surface acidification of the adsorbent

[0067] A mixture of concentrated nitric acid and concentrated sulfuric acid is prepared with a volume ratio of 1:3, kaolin is added to the acid mixture at a mass ratio of 15%, refluxed at 140°C for 8h, washed with deionized water to neutral after cooling, and then vacuum dried until completely dry. The kaolin with carboxyl groups (-COOH) on the surface is obtained.

[0068] Step 4, synthesis of modified adsorbent

[0069] The dithiocarbamate salt of the terminal amine group polybutadiene is condensed with the kaolin with carboxyl groups (-COOH) on the surface under the action of DCC dehydrating agent at a molar ratio of 1:1.5, the reaction temperature is 10°C, and the reaction time is 50h, generating a modified adsorbent that can complex with oil-soluble iron.

[0070] A filter cartridge made of the above prepared modified adsorbent is used to treat the lubricating oil with an iron content of 280ppm in a certain wind power plant, the adsorbent usage accounts for 5% of the mass of the lubricating oil to be treated, after 6 times of equivalent filtration, the oil-soluble iron content in the oil can be reduced to 12ppm.

[0071] Example 3

[0072] Step 1: amination of terminal hydroxyl group polybutadiene

[0073] 500g of terminal hydroxyl group polybutadiene is dissolved in 294g of 2-naphthalenesulfonyl chloride in dichloromethane, the molar ratio of terminal hydroxyl group polybutadiene to acyl chloride compound is 1:1.3, 79g of pyridine is dissolved in 298mL of dichloromethane to prepare a pyridine-dichloromethane solution with a mass fraction of 20%, which is added dropwise through a constant pressure dropping funnel at a rate of 1 drop / s, the molar ratio of terminal hydroxyl group polybutadiene to pyridine is 1:1, the reaction is carried out at 38°C under argon protection for 30h to prepare the terminal acyl polybutadiene compound, and the reaction product is washed with ethanol and dried.

[0074] 500g of the end-acyl polybutadiene compound and 84.5g of sodium azide were dissolved in N,N-dimethylformamide at a molar ratio of 1:1.3, and reacted at 50°C under argon protection for 15h to produce end-azido polybutadiene. The product was washed with ethanol and dried.

[0075] 500g of the end-azido polybutadiene and 97.5g of N,N-dimethylamino lithium borohydride were dissolved in anhydrous tetrahydrofuran at a molar ratio of 1:1.5, and reacted at 50°C under argon protection for 30h to produce end-amine polybutadiene. The product was washed with ethanol and dried.

[0076] Step 2: Dithiocarbamate of end-amine polybutadiene

[0077] The end-amine polybutadiene and dichloromethane were prepared into a solution at a mass ratio of 1:5, and at a temperature of 5°C, an aqueous solution of 7% NaOH with the same volume as the above solution was added, and carbon disulfide with an amount of 0.3 times the amount of substance of the end-amine polybutadiene was added at a rate of no more than 5% of the volume of carbon disulfide per minute, the temperature was maintained at 5°C and the reaction was continued for 3h. When a large amount of precipitate was generated at the bottom of the solution until no more precipitate was generated, the reaction was completed. The reaction product was suction filtered, washed with distilled water and methanol in sequence, and vacuum dried at 60°C for at least 8h to obtain the dithiocarbamate of the end-amine polybutadiene.

[0078] Step 3: Surface acidification of the adsorbent

[0079] A mixture of concentrated nitric acid and concentrated sulfuric acid was prepared at a volume ratio of 1:3, and activated carbon was added to the acid mixture at a mass ratio of 10% and refluxed at 100°C for 8h. After cooling, it was washed with deionized water until neutral, and then vacuum dried until completely dry. The kaolin with carboxyl groups (-COOH) on the surface was obtained.

[0080] Step 4: Synthesis of modified adsorbent

[0081] The dithiocarbamate of the end-amine polybutadiene and the activated carbon with carboxyl groups (-COOH) were condensed at a molar ratio of 1:1.3 in the presence of DCC dehydrating agent, the reaction temperature was 0°C, and the reaction time was 72h to produce the modified adsorbent capable of complexing with oil-soluble iron.

[0082] Example 4

[0083] Step 1: Amination of end-hydroxyl polybutadiene

[0084] 500g of hydroxyl-terminated polybutadiene and 316g of 2-naphthalenesulfonyl chloride were dissolved in dichloromethane, the molar ratio of hydroxyl-terminated polybutadiene to acyl chloride compound was 1:1.4, 79g of pyridine was dissolved in 298mL of dichloromethane to prepare a 20% pyridine-dichloromethane solution, which was added dropwise through a constant pressure dropping funnel at a rate of 1 drop / s, the molar ratio of hydroxyl-terminated polybutadiene to pyridine was 1:1, the reaction was carried out at 40°C under argon protection for 30h to prepare acyl-terminated polybutadiene compound, and the reaction product was washed with ethanol and dried.

[0085] 500g of acyl-terminated polybutadiene compound and 91g of sodium azide were dissolved in N,N-dimethylformamide according to a molar ratio of 1:1.4, the reaction was carried out at 60°C under argon protection for 15h to produce azido-terminated polybutadiene, and the product was washed with ethanol and dried.

[0086] 500g of azido-terminated polybutadiene and 97.5g of lithium borohydride were dissolved in anhydrous tetrahydrofuran according to a molar ratio of 1:1.5, the reaction was carried out at 50°C under argon protection for 30h to produce amine-terminated polybutadiene, and the product was washed with ethanol and dried.

[0087] Step 2, dithiocarbamate saltification of amine-terminated polybutadiene

[0088] Amine-terminated polybutadiene and dichloromethane were prepared into a solution according to a mass ratio of 1:5, an aqueous solution of 7% NaOH with the same volume as the above solution was added at a temperature of 10°C, and carbon disulfide was added at a rate of not more than 5% of the volume of carbon disulfide per minute, which was 0.3 times the amount of amine-terminated polybutadiene, the temperature was maintained at 10°C and the reaction continued for 3h, and the reaction ended when a large amount of precipitate was generated at the bottom of the solution until no more precipitate was generated. The reaction product was suction filtered, washed with distilled water and methanol in sequence, and dried under vacuum at 60°C for at least 8h to obtain the dithiocarbamate saltified amine-terminated polybutadiene product.

[0089] Step 3, surface acidification of adsorbent

[0090] A mixture of concentrated nitric acid and concentrated sulfuric acid was prepared according to a volume ratio of 1:3, kaolin was added to the acid mixture according to a mass ratio of 12%, and refluxed at 130°C for 8h, then washed with deionized water until neutral, and then vacuum dried until completely dry. The functional activated carbon fiber with carboxyl groups (-COOH) on the surface was obtained.

[0091] Step 4, synthesis of modified adsorbent

[0092] The dithio-carbamate-terminated polybutadiene amine is condensed with the functional active carbon fiber with carboxyl (-COOH) in a molar ratio of 1:1.4 in the presence of DCC dehydrating agent, the reaction temperature is 25℃, and the reaction time is 24h, to form a modified adsorbent capable of complexing with oil-soluble iron.

[0093] Example 5

[0094] Step 1, hydroxyl-terminated polybutadiene amination

[0095] The hydroxyl-terminated polybutadiene is sequentially reacted with 2-naphthalenesulfonyl chloride, sodium azide, and lithium borohydride to obtain amine-terminated polybutadiene.

[0096] The specific reaction is as follows:

[0097] 500g of hydroxyl-terminated polybutadiene is dissolved in 271g of 2-naphthalenesulfonyl chloride in dichloromethane, the molar ratio of hydroxyl-terminated polybutadiene to acyl chloride compound is 1:1.2, 79g of pyridine is dissolved in 298mL of dichloromethane to prepare a pyridine-dichloromethane solution with a mass fraction of 20%, which is added dropwise through a constant pressure dropping funnel at a rate of 1 drop / s, the molar ratio of hydroxyl-terminated polybutadiene to pyridine is 1:1, the reaction is carried out at 35℃ under argon protection for 30h to obtain acyl-terminated polybutadiene compound, and the reaction product is washed with ethanol and dried.

[0098] 500g of acyl-terminated polybutadiene compound is dissolved in 78g of sodium azide in N,N-dimethylformamide in a molar ratio of 1:1.2, the reaction is carried out at 40℃ under argon protection for 15h to obtain azido-terminated polybutadiene, and the product is washed with ethanol and dried.

[0099] 500g of azido-terminated polybutadiene and 78g of N,N-dimethylamino borohydride lithium are dissolved in anhydrous tetrahydrofuran in a molar ratio of 1:1.2, the reaction is carried out at 40℃ under argon protection for 30h to obtain amine-terminated polybutadiene, and the product is washed with ethanol and dried.

[0100] Step 2, dithio-carbamate-terminated polybutadiene amine

[0101] The amine-terminated polybutadiene and dichloromethane are prepared into a solution in a mass ratio of 1:5, at a temperature of 20℃, an equal volume of ammonia water with a mass concentration of 15% is added to the above solution, and 0.2 times the amount of amine-terminated polybutadiene in terms of substance is added to carbon disulfide at a rate of not more than 5% of the volume of carbon disulfide per minute, the temperature is maintained at 20℃, and the reaction is continued for 3h, when a large amount of precipitate is generated at the bottom of the solution until no more precipitate is generated, the reaction is completed. The reaction product is suction filtered, washed with distilled water and methanol in sequence, and dried under vacuum at 60℃ for at least 8h to obtain the dithio-carbamate-terminated polybutadiene amine.

[0102] Step 3, surface acidification of adsorbent

[0103] A mixture of concentrated nitric acid and concentrated sulfuric acid with a volume ratio of 1:3 was prepared, and activated clay was added into the acid mixture at a mass ratio of 15%. The mixture was refluxed at 120°C for 8h. After cooling, the mixture was washed with deionized water until neutral, and then vacuum dried until completely dry. Thus, the adsorbent with carboxyl groups (-COOH) on the surface was obtained.

[0104] Step 4, synthesis of modified adsorbent

[0105] The dithiocarbamate-terminated amine group polybutadiene with a molar ratio of 1:1.2 was condensed with the activated clay with carboxyl groups (-COOH) in the presence of dichlorosulfoxide dehydrating agent. The reaction temperature was 50°C, and the reaction time was 4h. The modified adsorbent with the ability to complex with oil-soluble iron was generated.

[0106] Example 6

[0107] Step 1, amination of hydroxyl-terminated polybutadiene

[0108] The hydroxyl-terminated polybutadiene was sequentially reacted with 2-naphthalenesulfonyl chloride, sodium azide, and lithium borohydride to prepare amine-terminated polybutadiene.

[0109] The specific reaction is as follows:

[0110] 500g of hydroxyl-terminated polybutadiene was dissolved in 271g of 2-naphthalenesulfonyl chloride in dichloromethane. The molar ratio of hydroxyl-terminated polybutadiene to acyl chloride compound was 1:1.2. Pyridine was used as a nucleophilic catalyst and an acid binding agent. 79g of pyridine was dissolved in 298mL of dichloromethane to prepare a pyridine-dichloromethane solution with a mass fraction of 20%. The solution was added dropwise through a constant pressure dropping funnel at a rate of 1 drop / s. The molar ratio of hydroxyl-terminated polybutadiene to pyridine was 1:1. The reaction was carried out at 35°C under argon protection for 30h to prepare acyl-terminated polybutadiene compounds. The reaction product was washed with ethanol and dried.

[0111] 500g of acyl-terminated polybutadiene compounds were dissolved in 78g of sodium azide in N,N-dimethylformamide at a molar ratio of 1:1.2. The reaction was carried out at 40°C under argon protection for 15h to generate azido-terminated polybutadiene. The product was washed with ethanol and dried.

[0112] 500g of azido-terminated polybutadiene and 78g of N,N-dimethylamino borohydride lithium were dissolved in anhydrous tetrahydrofuran at a molar ratio of 1:1.2. The reaction was carried out at 40°C under argon protection for 30h to obtain amine-terminated polybutadiene. The product was washed with ethanol and dried.

[0113] Step 2, dithiocarbamate of amine-terminated polybutadiene

[0114] The end-amine polybutadiene and dichloromethane are prepared into a solution with a mass ratio of 1:5, at a temperature of 20°C, an equal volume of 15% ammonia water is added to the above solution, and carbon disulfide is added at a rate of not more than 5% of the volume of carbon disulfide per minute, with the amount of substance of carbon disulfide being 0.2 times the amount of substance of the end-amine polybutadiene, and the temperature is maintained at 20°C to continue the reaction for 3h, and when a large amount of precipitate is generated at the bottom of the solution until no more precipitate is generated, the reaction is completed. The reaction product is suction filtered, washed with distilled water and methanol in sequence, and vacuum dried at 60°C for at least 8h, and the obtained product is the dithiocarbamate-terminated end-amine polybutadiene.

[0115] Step 3, surface acidification of the adsorbent

[0116] A concentrated nitric acid and concentrated sulfuric acid mixture with a volume ratio of 1:3 is prepared, and activated clay is added to the acid mixture at a mass ratio of 15%, and refluxed at 120°C for 8h, and after cooling, washed with deionized water until neutral, and then vacuum dried until completely dry. The adsorbent with a surface carboxyl group (-COOH) is obtained.

[0117] Step 4, synthesis of modified adsorbent

[0118] The dithiocarbamate-terminated end-amine polybutadiene and the activated clay with a carboxyl group (-COOH) are condensed under the action of a dichlorosulfoxide dehydrating agent, with a molar ratio of 1:1.2, at a reaction temperature of 70°C for 4h, to generate a modified adsorbent that can be complexed with oil-soluble iron.

[0119] The above only describes the preferred embodiments of the present application and is not intended to limit the present application, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for synthesizing an oil-soluble iron adsorbent, characterized by, The dithiocarbamate saltified end amine group polybutadiene is mixed with the adsorbent with carboxyl, and condensation reaction occurs under the action of acyl chloride to generate oil-soluble iron adsorbent; the adsorbent is activated clay, kaolin, activated carbon or functional active carbon fiber; The preparation process of the dithiocarbamate saltified end amine group polybutadiene is as follows: after end amine group polybutadiene and dichloromethane are mixed, an alkaline solution is added, then carbon disulfide is added, after the reaction is completed, the reaction product is washed and dried to obtain the dithiocarbamate saltified end amine group polybutadiene; The preparation process of the end amine group polybutadiene is as follows: end hydroxyl polybutadiene and 2-naphthalenesulfonyl chloride are dissolved in dichloromethane, pyridine-dichloromethane solution is added, and after reaction, end acyl polybutadiene compound is obtained; the end acyl polybutadiene compound and sodium azide are dissolved in N,N-dimethylformamide, and after reaction, end azide polybutadiene is obtained; the end azide polybutadiene and N,N-dimethylamino borohydride lithium are dissolved in anhydrous tetrahydrofuran, and after reaction, end amine group polybutadiene is obtained.

2. The method for synthesizing an oil-soluble iron adsorbent according to claim 1, characterized in that, The mixing molar ratio of the dithiocarbamate saltified end amine group polybutadiene and the adsorbent with carboxyl is 1:1.2-1.

5.

3. The method for synthesizing an oil-soluble iron adsorbent according to claim 1, characterized in that, The preparation process of the adsorbent with carboxyl is as follows: the adsorbent is added into an acid liquid mixture, the mass fraction of the adsorbent in the mixture is 10-15%, reflux reaction is carried out at 100-140 ℃ for 8 h, after the reaction system is cooled, the product is washed and dried to obtain the adsorbent with carboxyl; the acid liquid mixture is a mixture of concentrated nitric acid and concentrated sulfuric acid.

4. The method for synthesizing an oil-soluble iron adsorbent according to claim 1, characterized in that, The mixing mass ratio of the end amine group polybutadiene and dichloromethane is 1:5, the added amount of the alkaline solution is equal to the volume of the mixed solution of the end amine group polybutadiene and dichloromethane, and the added amount of carbon disulfide is 0.2-0.4 times the molar amount of the end amine group polybutadiene.

5. The method for synthesizing an oil-soluble iron adsorbent according to claim 1, characterized in that, The reaction temperature of the preparation process of the dithiocarbamate saltified end amine group polybutadiene is 5-30 ℃, and the reaction time is 3 h.

6. The method for synthesizing an oil-soluble iron adsorbent according to claim 1, characterized in that, The mixing molar ratio of the end hydroxyl polybutadiene and 2-naphthalenesulfonyl chloride is 1:1.2-1.5; the mixing molar ratio of the end acyl polybutadiene compound and sodium azide is 1:1.2-1.5; and the mixing molar ratio of the end azide polybutadiene and N,N-dimethylamino borohydride lithium is 1:1.

2.

7. The method for synthesizing an oil-soluble iron adsorbent according to claim 1, characterized in that, The reaction temperature of the end hydroxyl polybutadiene and 2-naphthalenesulfonyl chloride is 35-40 ℃, and the reaction time is 30 h; the reaction temperature of the end acyl polybutadiene compound and sodium azide is 40-60 ℃, and the reaction time is 15 h; and the reaction temperature of the end azide polybutadiene and N,N-dimethylamino borohydride lithium is 40 ℃, and the reaction time is 30 h.

8. An oil-soluble iron adsorbent obtained by the synthesis method according to any one of claims 1 to 7, characterized in that, The adsorbent is connected with the dithiocarbamate saltified end amine group polybutadiene through carboxyl.

9. Use of the oil-soluble iron adsorbent in claim 8 in adsorbing oil-soluble iron.

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