Method for recovering trifluoromethanesulfonic acid in a rubber plasticizer production process

Abstract

This invention belongs to the field of petroleum and petroleum fraction refining, specifically relating to a method for recovering trifluoromethanesulfonic acid during the production of rubber plasticizers. The method involves adding a certain mass of extractant to a rubber plasticizer containing trifluoromethanesulfonic acid, heating to a certain temperature for stirring and extraction, and after extraction, mixing the upper layer with light hydrocarbons, separating the light hydrocarbon phase, and distilling the remaining solvent phase to recover the extractant, thereby obtaining the recovered trifluoromethanesulfonic acid.

Description

Technical Field

[0001] This invention belongs to the field of petroleum and petroleum fraction refining, specifically relating to a method for recovering trifluoromethanesulfonic acid during the production of rubber plasticizers. The international patent classification is C10G. Background Technology

[0002] Rubber, as a strategically fundamental material, is crucial to all aspects of people's livelihood and social well-being, playing a vital role in these areas. Rubber is primarily composed of long-chain high-molecular-weight compounds with numerous branched chains. Rubber plasticizers (also known as rubber oils) can fill the gaps between these branches, thereby reducing the bonds and forces between rubber molecules. Therefore, adding rubber oil during rubber production can increase the plasticity of the rubber compound, improve the mixing process and vulcanization process, and enhance the various physical and mechanical properties of the vulcanized rubber.

[0003] Currently, my country still primarily uses traditional high-aromatic rubber oils in its rubber production processes. These oils have excellent compatibility with rubber and provide good performance to rubber products, making them widely used by Chinese rubber product manufacturers. However, aromatic rubber oils contain a large number of carcinogenic, teratogenic, and mutagenic polycyclic aromatic hydrocarbons (PAHs). Furthermore, with increasing environmental awareness and growing concern for personal health, traditional aromatic oils are no longer suitable, making the development and promotion of new environmentally friendly rubber plasticizers an urgent priority.

[0004] Based on differences in composition, rubber oils in my country are mainly classified into three categories: paraffinic, naphthenic, and aromatic. Aromatic rubber oils (DAEs) have significantly higher compatibility and processing performance with rubber than other rubber oils. They are less likely to spray off the surface of rubber products and are suitable for various synthetic and natural rubbers, thus enjoying large industrial usage. However, the large amount of polycyclic aromatic hydrocarbons (PAHs) contained in aromatic oils can pollute the environment and have carcinogenic effects on humans during the production, processing, use, and waste disposal of tires, hoses, and other rubber products. However, the EU Directive 2005 / 69 / EC, "Restrictions on the Placement on the Market and Use of Certain Hazardous Substances and Preparations (Polycyclic Aromatic Hydrocarbons in Filler Oils and Tires)" (REACH Regulation), stipulates that if the benzo[a]pyrene (BaP) content in filler oils exceeds 1 mg / kg or the content of eight specific PAHs exceeds 10 mg / kg, it cannot be placed on the market or used in the production of tire components. Rubber oils that meet these requirements are called environmentally friendly rubber plasticizers (oils). my country has also formulated a standard for environmentally friendly rubber oil (National Standard GB / T33322-2016 Rubber Plasticizer Aromatic Mineral Oil), which defines environmentally friendly rubber oil as a rubber plasticizer. The standard also stipulates that the content of benzo[a]pyrene (BaP) is greater than 1 mg / kg or the content of 8 specific polycyclic aromatic hydrocarbons (PAHs) is greater than 10 mg / kg, but this standard has not yet been enforced.

[0005] Traditional aromatic oils (DAEs) contain significantly higher levels of polycyclic aromatic hydrocarbons (PAHs) than those required by REACH regulations. Currently, my country relies heavily on imports for environmentally friendly rubber plasticizers, which are expensive. Furthermore, regulatory requirements have severely impacted my country's tire and rubber product industries. Therefore, rubber plasticizer manufacturers and rubber product producers are undoubtedly paying close attention to the research and application of environmentally friendly high-aromatic rubber oils.

[0006] Currently, the main methods for producing environmentally friendly rubber plasticizers are hydrogenation refining, chemical synthesis, and solvent refining. Environmentally friendly rubber plasticizers produced through hydrogenation refining easily meet EU environmental regulations; however, during the hydrogenation process, a large amount of aromatics are saturated or cracked, resulting in a low aromatic carbon content (C1) of the product. AThe low yield makes it difficult to produce high-performance products, significantly reducing their value. Synthetic methods primarily involve the alkylation of aromatics and olefins, typically using catalysts such as concentrated sulfuric acid, anhydrous aluminum trichloride, and hydrofluoric acid. These catalysts are difficult to separate from the product oil, generating large amounts of wastewater that is difficult and costly to treat, and polluting the environment. Currently, solvent refining is commonly used in China to produce environmentally friendly rubber plasticizers. This method involves using a suitable solvent to extract and refine the feedstock oil once or multiple times, removing large amounts of polycyclic aromatic hydrocarbons and other substances, ensuring the final product meets environmental requirements while retaining a high aromatic carbon content. However, the feedstock oil used in producing environmentally friendly rubber plasticizers is mostly extracted oil generated during lubricant production. Due to increasingly stringent quality requirements for lubricants, traditional lubricant production methods are shifting from solvent refining-solvent dewaxing to hydrogenation processes, leading to a continuous decrease in extracted oil production. Therefore, finding raw materials and new synthetic methods for producing environmentally friendly rubber plasticizers is urgently needed.

[0007] Diesel and cycle oil produced by catalytic cracking in oil refineries have high aromatic content and large yields. These aromatic components can be synthesized into ideal components for environmentally friendly rubber plasticizers through alkylation with olefins, greatly improving the value of the raw materials. Patent application 2017110615449 proposes a method for producing environmentally friendly rubber filler oil from diesel, using anhydrous AlCl3 as a catalyst to react diesel with olefins to obtain the environmentally friendly rubber filler oil. However, the anhydrous aluminum trichloride alkylation process involves numerous side reactions, making product separation from the catalyst difficult, generating large amounts of acidic wastewater, polluting the environment, and incurring high treatment costs. Therefore, a synthesis technology using trifluoromethanesulfonic acid as a catalyst was developed. However, due to the high production cost and price of trifluoromethanesulfonic acid, its use as a catalyst in the production of environmentally friendly rubber plasticizers also faces the problems of high production costs and low economic efficiency. Therefore, a new method for recovering trifluoromethanesulfonic acid is needed. Summary of the Invention

[0008] To overcome the shortcomings of the prior art, this invention provides a method for recovering trifluoromethanesulfonic acid during the production of environmentally friendly rubber plasticizers. The method utilizes solvent extraction to extract and recover trifluoromethanesulfonic acid from the product oil for reuse. Furthermore, the extraction process is very mild, and extraction and recovery can be carried out at relatively low temperatures and atmospheric pressures. The operation is simple, energy consumption is low, and the cost of producing environmentally friendly rubber plasticizers is greatly reduced.

[0009] The technical solution adopted in this invention is as follows:

[0010] 1. A method for recovering trifluoromethanesulfonic acid during the production of rubber plasticizers, characterized in that, during the synthesis of rubber plasticizers using trifluoromethanesulfonic acid as a catalyst, after the reaction is completed, a certain amount of extractant is added to the reaction oil mixture in a certain proportion, and the mixture is stirred at a certain temperature for a period of time. After extraction, the mixture is allowed to stand and separate into layers, the upper extract phase and the lower raffinate phase are separated, an appropriate amount of light hydrocarbons are added to the extract phase and mixed, and then the upper light hydrocarbon phase is separated by standing. The lower extractant phase is heated to 100-120℃ and distilled to recover the extractant. The distillation residue is a mixture of recovered trifluoromethanesulfonic acid and a small amount of oil, which can be reused as a catalyst.

[0011] 2. The method according to 1, wherein the reaction oil mixture is the product of the reaction between catalytic cracked diesel and olefins in a petroleum refinery.

[0012] 3. The method according to 1, wherein the reaction oil mixture is the product of the reaction between catalytic cracking cycle oil and olefins in a petroleum refinery.

[0013] 4. The method according to 1, wherein the extractant is methanol.

[0014] 5. The method according to 1, wherein the extractant is ethanol.

[0015] 6. The method according to 1, characterized in that the volume ratio of extractant to rubber oil during each extraction is 0.2-2:1.

[0016] 7. The method according to 1, characterized in that the extraction temperature is 30-60℃ and the stirring time is 5min-30min.

[0017] 8. The method according to 1, wherein the light hydrocarbon is a saturated hydrocarbon with 5 to 10 carbon atoms.

[0018] 9. The method according to 1, characterized in that the volume ratio of light hydrocarbon to extract phase is 0.2:1.

[0019] Of course, the more extractions are performed, the higher the recovery rate of trifluoromethanesulfonic acid. According to experimental data, three extractions yielded the best results. The extraction process can also be carried out using an extraction tower. In practical applications, to simplify the process, extraction with light hydrocarbons can be omitted, and direct distillation can be performed instead; however, this will result in a product with a higher oil content.

[0020] Invention Effects

[0021] By using the method provided in this invention patent, the recovery rate of trifluoromethanesulfonic acid can reach over 85%, and the recovered catalyst can be reused, which greatly reduces production costs, pollutant emissions, and corrosion in subsequent distillation processes. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1

[0024] (a) 600g of catalytic cracked diesel oil and 300g of dodecene from a certain refinery were placed into a 2000mL three-necked flask and stirred until they were evenly mixed.

[0025] (b) Add 9g of trifluoromethanesulfonic acid to below the oil surface, control the heating temperature at 150°C, and start timing until the reaction time reaches 60min.

[0026] (c) After the reaction is complete, cool to 50°C. A dark green liquid can be observed. Add 270g of methanol and stir to extract at 50°C for 10 minutes.

[0027] (d) After extraction, the product is poured into a separatory funnel. The upper layer is a dark methanol-catalyst phase and the lower layer is a dark green product oil phase. After separating the upper methanol-catalyst phase, it is washed with 90g of n-pentane to remove a small amount of product oil. The upper n-pentane phase is distilled to recover the solvent n-pentane. The lower methanol-catalyst phase is heated to 100℃ and distilled to recover the solvent methanol. The remaining substance in the distillation flask is a mixture of trifluoromethanesulfonic acid and a small amount of oil.

[0028] (e) The content of trifluoromethanesulfonic acid was determined by acid-base titration with 0.05 mol / L KOH-ethanol solution, and the recovery rate was calculated to be 90.2%.

[0029] Example 2

[0030] (a) 800g of catalytic cracking cycle oil and 400g of dodecene from a certain refinery were put into a 3000mL three-necked flask and stirred to mix them evenly.

[0031] (b) Add 12g of trifluoromethanesulfonic acid to below the oil surface, control the heating temperature at 150°C, and start timing until the reaction time reaches 60min.

[0032] (c) After the reaction is complete, cool to 50°C. A dark green liquid can be observed. Add 360g of methanol and stir to extract at 50°C for 10 minutes.

[0033] (d) After extraction, the product is poured into a separatory funnel. The upper layer is a dark methanol-catalyst phase and the lower layer is a dark green product oil phase. After separating the upper methanol-catalyst phase, it is washed with 120g of decane to remove a small amount of product oil. The upper decane phase is distilled to recover the solvent decane. The lower methanol-catalyst phase is heated to 100℃ and distilled to recover the solvent methanol. The remaining substance in the distillation flask is a mixture of trifluoromethanesulfonic acid and a small amount of oil.

[0034] (e) The recovery rate was 88.3% as determined by acid-base titration with 0.05 mol / L KOH-ethanol solution to determine the content of trifluoromethanesulfonic acid.

[0035] Example 3

[0036] (a) 700g of catalytic cracked diesel oil and 350g of dodecene from a certain refinery were placed into a 2000mL three-necked flask and stirred until they were mixed evenly.

[0037] (b) Add 10.5g of trifluoromethanesulfonic acid below the oil surface, control the heating temperature at 150°C, and start timing until the reaction time reaches 60min.

[0038] (c) After the reaction is complete, cool to 50°C. A dark green liquid can be observed. Add 315g of methanol and stir to extract at 50°C for 20 minutes.

[0039] (d) After extraction, the product is poured into a separatory funnel. The upper layer is a dark methanol-catalyst phase and the lower layer is a dark green product oil phase. After separating the upper methanol-catalyst phase, it is washed with 95g of cyclohexane to remove a small amount of product oil. The upper cyclohexane phase is distilled to recover the solvent cyclohexane. The lower methanol-catalyst phase is heated to 120℃ and distilled to recover the solvent methanol. The remaining substance in the distillation flask is a mixture of trifluoromethanesulfonic acid and a small amount of oil.

[0040] (e) The content of trifluoromethanesulfonic acid was determined by acid-base titration with 0.05 mol / L KOH-ethanol solution, and the recovery rate was calculated to be 91.4%.

[0041] Example 4

[0042] (a) 800g of catalytic cracking cycle oil and 400g of dodecene from a certain refinery were put into a 3000mL three-necked flask and stirred to mix them evenly.

[0043] (b) Add 12g of trifluoromethanesulfonic acid to below the oil surface, control the heating temperature at 150°C, and start timing until the reaction time reaches 60min.

[0044] (c) After the reaction is complete, cool to 40°C. A dark green liquid can be observed. Add 360g of methanol and stir to extract at 40°C for 30 minutes.

[0045] (d) After extraction, pour the mixture into a separatory funnel. The upper layer is a dark methanol-catalyst phase, and the lower layer is a dark green product oil phase. After separating the upper methanol-catalyst phase, wash it with 120g of petroleum ether (boiling range 60-90℃) to remove a small amount of product oil. Distill the upper petroleum ether phase to recover the solvent petroleum ether, and distill the lower methanol-catalyst phase to recover the solvent methanol. Repeat the extraction three times. The remaining substance in the distillation flask is a mixture of trifluoromethanesulfonic acid and a small amount of oil.

[0046] (e) The recovery rate was 92.2% as determined by acid-base titration with 0.05 mol / L KOH-ethanol solution to determine the content of trifluoromethanesulfonic acid.

[0047] Example 5

[0048] (a) 800g of catalytic cracking cycle oil and 400g of dodecene from a certain refinery were put into a 3000mL three-necked flask and stirred to mix them evenly.

[0049] (b) Add 12g of trifluoromethanesulfonic acid to below the oil surface, control the heating temperature at 150°C, and start timing until the reaction time reaches 60min.

[0050] (c) After the reaction is complete, cool to 40°C. A dark green liquid can be observed. Add 360g of methanol and stir to extract at 40°C for 60 minutes.

[0051] (d) After extraction, pour the mixture into a separatory funnel. The upper layer is a dark methanol-catalyst phase, and the lower layer is a dark green product oil phase. After separating the upper methanol-catalyst phase, wash it with 120g of petroleum ether (boiling range 90-120℃) to remove a small amount of product oil. Distill the upper petroleum ether phase to recover the solvent petroleum ether, and distill the lower methanol-catalyst phase to recover the solvent methanol. The remaining substance in the distillation flask is a mixture of trifluoromethanesulfonic acid and a small amount of oil.

[0052] (e) The recovery rate was 92.6% as determined by acid-base titration with 0.05 mol / L KOH-ethanol solution to determine the content of trifluoromethanesulfonic acid.

[0053] Example 6

[0054] Using the trifluoromethanesulfonic acid mixture recovered in Example 5 as a catalyst, 700g of catalytic cracking diesel oil and 350g of dodecene from a refinery were placed in a 2000mL three-necked flask and stirred until homogeneous. 10.5g of trifluoromethanesulfonic acid was added to below the oil level, and the heating temperature was controlled at 150°C. Timing was started until the reaction time reached 60 minutes. By measuring the yield, viscosity, and distillation range of the reaction products, it was found that the effect was comparable to that of fresh trifluoromethanesulfonic acid, indicating that the recovered catalyst can be reused.

[0055] Example 7

[0056] (a) 700g of catalytic cracked diesel oil and 350g of dodecene from a certain refinery were placed into a 2000mL three-necked flask and stirred until they were mixed evenly.

[0057] (b) Add 10.5g of trifluoromethanesulfonic acid below the oil surface, control the heating temperature at 150°C, and start timing until the reaction time reaches 60min.

[0058] (c) After the reaction is complete, cool to 50°C. A dark green liquid can be observed. Add 320 ml of ethanol and stir to extract at 50°C for 20 min.

[0059] (d) After extraction, pour the mixture into a separatory funnel. The upper layer is a dark ethanol-catalyst phase and the lower layer is a dark green product oil phase. After separating the upper ethanol-catalyst phase, the ethanol is recovered by distillation. The remaining substance in the distillation flask is a mixture of trifluoromethanesulfonic acid and some oil.

[0060] (e) The content of trifluoromethanesulfonic acid was determined by acid-base titration with 0.05 mol / L KOH-ethanol solution, and the recovery rate was calculated to be 88.5%.

[0061] (f) Using recycled trifluoromethanesulfonic acid as a catalyst to synthesize rubber plasticizers, with effects comparable to those using fresh catalysts.

[0062] Example 8

[0063] (a) 700g of catalytic cracked diesel oil and 350g of dodecene from a certain refinery were placed into a 2000mL three-necked flask and stirred until they were mixed evenly.

[0064] (b) Add 10.5g of trifluoromethanesulfonic acid below the oil surface, control the heating temperature at 150°C, and start timing until the reaction time reaches 60min.

[0065] (c) After the reaction is completed, cool to 50°C and observe a dark green liquid. Add 320 ml of a 1:1 mixture of methanol and ethanol and control the extraction temperature at 60°C for stirring and extraction for 20 min.

[0066] (d) After extraction, pour the mixture into a separatory funnel. The upper layer is a dark alcohol-catalyst phase, and the lower layer is a dark green product oil phase. After separating the upper alcohol-catalyst phase, distill to recover methanol and ethanol. The remaining substance in the distillation flask is a mixture of trifluoromethanesulfonic acid and some oil.

[0067] (e) The content of trifluoromethanesulfonic acid was determined by acid-base titration with 0.05 mol / L KOH-ethanol solution, and the recovery rate was calculated to be 91.2%.

[0068] (f) Using recycled trifluoromethanesulfonic acid as a catalyst to synthesize rubber plasticizers, with effects comparable to those using fresh catalysts.

[0069] The above examples demonstrate that using solvents such as methanol and ethanol for extraction and recovery of trifluoromethanesulfonic acid results in a high recovery rate and allows for the recycling of the separated catalyst, thus reducing the cost of catalyst use.

[0070] Of course, the above description is only one embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principle of the present invention, and these improvements and modifications are all within the protection scope of the claims of the present invention.

Claims

1. A method for recovering trifluoromethanesulfonic acid during the production of rubber plasticizers, characterized in that: (1) Put 600g of catalytic cracked diesel and 300g of dodecene into a 2000mL three-necked flask and stir to mix them evenly. (2) Add 9g of trifluoromethanesulfonic acid to below the oil surface, control the heating temperature at 150℃, and start timing until the reaction time reaches 60min; (3) After the reaction is completed, cool to 50°C and observe a dark green liquid. Add 270g of methanol and stir to extract at 50°C for 10 minutes. (4) After extraction, pour it into a separatory funnel. The upper layer is a dark methanol-catalyst phase and the lower layer is a dark green product oil phase. After separating the upper methanol-catalyst phase, wash it with 90g of n-pentane to remove a small amount of product oil. Distill the upper n-pentane phase to recover the solvent n-pentane. Heat the lower methanol-catalyst phase to 100℃ and distill to recover the solvent methanol. The remaining substance in the distillation flask is a mixture of trifluoromethanesulfonic acid and a small amount of oil. (5) The content of trifluoromethanesulfonic acid was determined by acid-base titration with 0.05 mol / L KOH-ethanol solution, and the recovery rate was calculated to be 90.2%.

2. A method for recovering trifluoromethanesulfonic acid during the production of rubber plasticizers, characterized in that: (1) Put 700g of catalytic cracked diesel and 350g of dodecene into a 2000mL three-necked flask and stir to mix them evenly. (2) Add 10.5g of trifluoromethanesulfonic acid to below the oil surface, control the heating temperature at 150℃, and start timing until the reaction time reaches 60min; (3) After the reaction is complete, cool to 50°C and observe a dark green liquid. Add 320 ml of ethanol, control the extraction temperature at 50°C and stir to extract, maintaining the extraction time for 20 min. (4) After extraction, pour it into a separatory funnel. The upper layer is a dark ethanol-catalyst phase and the lower layer is a dark green product oil phase. After separating the upper ethanol-catalyst phase, distill to recover the ethanol. The remaining substance in the distillation flask is a mixture of trifluoromethanesulfonic acid and some oil. (5) The content of trifluoromethanesulfonic acid was determined by acid-base titration with 0.05 mol / L KOH-ethanol solution, and the recovery rate was calculated to be 88.5%. (6) Using recycled trifluoromethanesulfonic acid as a catalyst to synthesize rubber plasticizers has an effect comparable to that of using fresh catalysts.

3. A method for recovering trifluoromethanesulfonic acid during the production of rubber plasticizers, characterized in that: (1) Put 700g of catalytic cracked diesel and 350g of dodecene into a 2000mL three-necked flask and stir to mix them evenly. (2) Add 10.5g of trifluoromethanesulfonic acid to below the oil surface, control the heating temperature at 150℃, and start timing until the reaction time reaches 60min; (3) After the reaction is completed, cool to 50°C and observe a dark green liquid. Add 320 ml of a 1:1 mixture of methanol and ethanol and control the extraction temperature at 60°C for stirring and extraction for 20 min. (4) After extraction, pour it into a separatory funnel. The upper layer is a dark alcohol-catalyst phase and the lower layer is a dark green product oil phase. After separating the upper alcohol-catalyst phase, distill to recover methanol and ethanol. The remaining substance in the distillation flask is a mixture of trifluoromethanesulfonic acid and some oil. (5) The content of trifluoromethanesulfonic acid was determined by acid-base titration with 0.05 mol / L KOH-ethanol solution, and the recovery rate was calculated to be 91.2%. (6) Using recycled trifluoromethanesulfonic acid as a catalyst to synthesize rubber plasticizers has an effect comparable to that of using fresh catalysts.

4. A method for recovering trifluoromethanesulfonic acid during the production of rubber plasticizers, characterized in that: (1) Put 800g of catalytic cracking cycle oil and 400g of dodecene into a 3000mL three-necked flask and stir to mix them evenly. (2) Add 12g of trifluoromethanesulfonic acid to below the oil surface, control the heating temperature at 150℃, and start timing until the reaction time reaches 60min; (3) After the reaction is completed, cool to 40°C and observe a dark green liquid. Add 360g of methanol and stir to extract at 40°C for 30 minutes. (4) After extraction, pour it into a separatory funnel. The upper layer is a dark methanol-catalyst phase and the lower layer is a dark green product oil phase. After separating the upper methanol-catalyst phase, wash it with 120g of petroleum ether with a boiling range of 60-90℃ to remove a small amount of product oil. Distill the upper petroleum ether phase to recover the solvent petroleum ether and the lower methanol-catalyst phase to recover the solvent methanol. Repeat the extraction 3 times. The remaining substance in the distillation flask is a mixture of trifluoromethanesulfonic acid and a small amount of oil. (5) The content of trifluoromethanesulfonic acid was determined by acid-base titration with 0.05 mol / L KOH-ethanol solution, and the recovery rate was calculated to be 92.2%.