A method for producing rubber vulcanizing agent 4,4'-dithiodimorpholine

Abstract

The invention discloses a kind of production method of rubber vulcanizing agent 4,4'-dithiodimorpholine, comprising the steps: solvent, acid binding agent, morpholine are added into reactor simultaneously, stirring and mixing, controlling temperature at 20-60 DEG C, dropping oxidant while stirring, dropping in 1-5h, continuing insulation reaction 6-8h after dropping, multi-energy field auxiliary treatment 15-25min during insulation reaction, after reaction terminates, insoluble matter is filtered out, crude product solution is washed with water, standing 5-10min, lower washing water is released after layering, upper mixed layer enters freezing kettle for freezing, centrifugal filtration, solvent recovery, filter cake is dried, ground and sieved, packaged after reaching standard, rubber vulcanizing agent 4,4'-dithiodimorpholine is obtained. The method can realize the recycling of solvent, increase product yield and purity, and reduce hazardous waste generated in distillation process at the same time.

Description

Technical Field

[0001] The invention relates to the technical field of rubber additive synthesis, in particular to a method for producing a rubber vulcanizing agent 4,4'-dithiodimorpholine. Background Art

[0002] Rubber materials are one of the important basic materials in social life. Rubber materials are used in all aspects of social life, such as automobile tires, sealing materials, conveyor belts, shock-absorbing materials, electrical insulation materials, etc., and they play an irreplaceable role in people's lives. Ordinary rubber raw rubber has poor performance, and vulcanizers need to be added when it is made into rubber products. 4,4'-Dithiodimorpholine (DTDM) is an important rubber vulcanizer. It can decompose active sulfur at the vulcanization temperature. It has the advantages of safe operation, no frosting, no discoloration, and no pollution. It is suitable for various dynamic products. It is often used in the manufacture of high-quality rubber products such as radial tires, engineering tires, bias tires, butyl inner tubes and rubber seals. It can also be used as a highway asphalt stabilizer. With the further expansion of its application range, the market demand for 4,4'-dithiodimorpholine is increasing.

[0003] The existing 4,4'-dithiodimorpholine production method uses distillation technology to distill the solvent in the production process to separate the substances dissolved in the solvent to achieve the reuse of the solvent. The process not only consumes steam and electricity, but also produces a large amount of hazardous waste, resulting in high production costs and low ecological value of the product, affecting the economic benefits of 4,4'-dithiodimorpholine products, and thus resulting in low market competitiveness of the 4,4'-dithiodimorpholine project. In addition, the acid binding agent commonly used in the production of 4,4'-dithiodimorpholine is morpholine itself or sodium hydroxide. When morpholine is used as an acid binding agent, there is a problem of large-scale waste of morpholine. At the same time, the morpholine recovery process is complicated and the wastewater generated is difficult to treat; when sodium hydroxide is used as an acid binding agent, water is generated when sodium hydroxide reacts with hydrochloric acid, and the presence of water will cause sulfur monochloride to decompose and produce a side reaction, resulting in a low yield and poor quality of the final product, and it is difficult to meet the index requirements.

[0004] In order to solve the above problems, the Chinese invention patent with the authorization announcement number CN110330468B discloses a method for synthesizing 4,4'-dithiodimorpholine, which uses sulfur monochloride and morpholine as raw materials, and anhydrous trisodium phosphate as an acid binding agent. Sulfur monochloride and morpholine react to generate 4,4'-dithiodimorpholine and hydrochloric acid. Anhydrous trisodium phosphate can react with the hydrochloric acid generated in the reaction to avoid the reaction of hydrochloric acid with morpholine, thereby making morpholine lose its reactivity. The inventive method can reduce the amount of raw material morpholine by adding anhydrous trisodium phosphate, an acid binding agent, and save production costs. In addition, the product can be separated from impurities by washing with water after the reaction. The production process is simple, the operability is strong, the post-processing is simple, and it has industrial application value. The appearance of the obtained product is white needle-shaped crystals, the yield is more than 90%, and the purity is more than 98%, which meets the use requirements. However, it does not recycle the solvent in the synthesis process, which not only causes a waste of resources, but also easily causes environmental problems.

[0005] It can be seen that it is necessary to develop a production method for the rubber vulcanizing agent 4,4'-dithiodimorpholine which can not only realize the recycling of solvents, but also increase the yield and purity of products and reduce the hazardous waste generated during the distillation process. Summary of the invention

[0006] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method for producing a rubber vulcanizing agent 4,4'-dithiodimorpholine, which can realize the recycling of solvents, increase product yield and purity, and reduce hazardous waste generated during the distillation process.

[0007] To achieve the above purpose, the technical scheme adopted by the present invention is: a production method of rubber vulcanizing agent 4,4'-dithiodimorpholine, comprising the following steps: adding a solvent, an acid binding agent and morpholine into a reaction kettle at the same time, stirring and mixing, controlling the temperature at 20-60°C, adding an oxidant dropwise while stirring, and completing the dropwise addition within 1-5 hours, continuing the heat preservation reaction for 6-8 hours after the dropwise addition is completed, performing multi-energy field auxiliary treatment for 15-25 minutes during the heat preservation reaction, stopping stirring after the reaction is completed, filtering to remove insoluble matter, washing the filter cake with a solvent, and combining the washing liquid with the filtrate to obtain a crude product solution, washing the crude product solution with water, standing for 5-10 minutes, releasing the lower layer of washing water after stratification, and the upper layer of 4,4'-dithiodimorpholine product solvent mixed layer entering a freezing kettle for freezing, centrifugal filtration, recovering the solvent, drying, grinding and sieving the filter cake, and packaging after reaching the standard to obtain the rubber vulcanizing agent 4,4'-dithiodimorpholine.

[0008] Preferably, the solvent is at least one of n-heptane, n-hexane, and 120# solvent oil.

[0009] Preferably, the oxidant is sulfur monochloride.

[0010] Preferably, the mass ratio of the solvent, the acid binding agent and the morpholine is (8-12):(1.5-2):1.

[0011] Preferably, the molar ratio of morpholine to oxidant is 2:1.

[0012] Preferably, the acid binding agent is a mixture of sodium acetate, zeolite molecular sieve and quinoline in a mass ratio of 1:(1-3):(0.3-0.5).

[0013] Preferably, the zeolite molecular sieve is ZSM-5 molecular sieve.

[0014] Preferably, the multi-energy field includes ultrasound, a steady magnetic field and an electromagnetic oscillation field.

[0015] Preferably, the frequency of the ultrasonic wave is 95-125kHz, and the power is 180-260W; the magnetic field strength of the steady magnetic field is 7000-13000Gs; the frequency of the electromagnetic oscillation field is 15-30HZ, and the medium and low duty cycle is 20-30%.

[0016] Preferably, the freezing temperature is -10 to -30°C and the freezing time is 3 to 6 hours.

[0017] Preferably, the drying, grinding and screening is through a 200-300 mesh sieve.

[0018] Due to the application of the above technical solution, the present invention has the following beneficial effects:

[0019] (1) The production method of the rubber vulcanizing agent 4,4'-dithiodimorpholine disclosed in the present invention has high product output rate, low energy consumption and less three-waste emission through reasonable selection of process parameters and raw materials. It can not only realize the recycling of solvents, but also increase product yield and purity, while reducing hazardous waste generated in the distillation process. The production process has little impact on the environment, low labor intensity, low dependence on equipment, is suitable for continuous large-scale production, effectively realizes the organic unity of economic benefits, social benefits and ecological benefits, and has high promotion and application value.

[0020] (2) The present invention discloses a method for producing a rubber vulcanizing agent 4,4'-dithiodimorpholine, wherein the acid-binding agent is a mixture of sodium acetate, zeolite molecular sieve and quinoline in a mass ratio of 1:(1-3):(0.3-0.5); the decomposition of sulfur monochloride caused by generated water, the problem of low product yield and poor purity are avoided, and the product yield and purity are effectively increased; after the reaction is completed, the acid-binding agent can be recycled, thereby reducing costs and protecting the environment.

[0021] (3) The production method of the rubber vulcanizing agent 4,4'-dithiodimorpholine disclosed in the present invention adopts multi-energy field auxiliary treatment during the reaction process, and the multi-energy field includes ultrasound, a steady magnetic field and an electromagnetic oscillation field; it can effectively improve the reaction rate, reaction conversion rate and selectivity, and improve the product purity and yield.

[0022] (4) The production method of the rubber vulcanizing agent 4,4'-dithiodimorpholine disclosed in the present invention adopts low-temperature precipitation technology, specifically, solvent freezing technology instead of solvent distillation technology, which can reduce energy consumption and realize solvent recovery and reuse safely, quickly and efficiently, thereby increasing economic benefits and reducing hazardous waste. It is a green and environmentally friendly process; at the same time, it can also improve product yield and purity. DETAILED DESCRIPTION

[0023] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art may think of other obvious variations.

[0024] Example 1

[0025] A production method of a rubber vulcanizing agent 4,4'-dithiodimorpholine comprises the following steps: adding a solvent, an acid binding agent and morpholine into a reaction kettle at the same time, stirring and mixing, controlling the temperature at 20 DEG C, dripping an oxidant while stirring, completing the dripping within 1 hour, continuing to heat-keep the reaction for 6 hours after the dripping is completed, performing a multi-energy field auxiliary treatment for 15 minutes during the heat-keep reaction, stopping stirring after the reaction is completed, filtering to remove insoluble matter, washing a filter cake with a solvent, combining the washing liquid with a filtrate to obtain a crude product solution, washing the crude product solution with water, standing for 5 minutes, releasing the lower washing water after stratification, and placing the upper 4,4'-dithiodimorpholine product solvent mixed layer into a freezing kettle for freezing, centrifugation filtering, recovering the solvent, drying, grinding and sieving the filter cake, and packaging after reaching the standard to obtain the rubber vulcanizing agent 4,4'-dithiodimorpholine.

[0026] The solvent is n-heptane; the oxidant is sulfur monochloride; the mass ratio of the solvent, the acid binding agent and morpholine is 8:1.5:1; the molar ratio of morpholine and the oxidant is 2:1; the acid binding agent is a mixture of sodium acetate, zeolite molecular sieve and quinoline in a mass ratio of 1:1:0.3; and the zeolite molecular sieve is ZSM-5 molecular sieve.

[0027] The multi-energy field includes ultrasound, a steady magnetic field and an electromagnetic oscillation field; the frequency of the ultrasound is 95kHz and the power is 180W; the magnetic field strength of the steady magnetic field is 7000Gs; the frequency of the electromagnetic oscillation field is 15HZ, and the medium and low duty cycle is 20%; the freezing temperature is -10°C and the time is 3h; the drying, grinding and screening is through a 200-mesh sieve.

[0028] Through detection, it was determined that the yield of the rubber vulcanizing agent 4,4'-dithiodimorpholine prepared by the production method of the rubber vulcanizing agent 4,4'-dithiodimorpholine was 99.45% (calculated as morpholine) and the HPLC purity was 99.80%.

[0029] Example 2

[0030] A production method of a rubber vulcanizing agent 4,4'-dithiodimorpholine comprises the following steps: adding a solvent, an acid binding agent and morpholine into a reaction kettle at the same time, stirring and mixing, controlling the temperature at 30 DEG C, dripping an oxidant while stirring, completing the dripping within 2 hours, continuing to heat-keep the reaction for 6.5 hours after the dripping is completed, performing a multi-energy field auxiliary treatment for 17 minutes during the heat-keep reaction, stopping stirring after the reaction is completed, filtering to remove insoluble matter, washing a filter cake with a solvent, combining the washing liquid with a filtrate to obtain a crude product solution, washing the crude product solution with water, standing for 6 minutes, releasing the lower washing water after stratification, and placing the upper 4,4'-dithiodimorpholine product solvent mixed layer into a freezing kettle for freezing, centrifugation filtering, recovering the solvent, drying, grinding and sieving the filter cake, and packaging after reaching the standard to obtain the rubber vulcanizing agent 4,4'-dithiodimorpholine.

[0031] The solvent is n-hexane; the oxidant is sulfur monochloride; the mass ratio of the solvent, the acid binding agent and morpholine is 9:1.7:1; the molar ratio of morpholine and the oxidant is 2:1; the acid binding agent is a mixture of sodium acetate, zeolite molecular sieve and quinoline in a mass ratio of 1:1.5:0.35; and the zeolite molecular sieve is ZSM-5 molecular sieve.

[0032] The multi-energy field includes ultrasound, a steady magnetic field and an electromagnetic oscillation field; the frequency of the ultrasound is 100kHz and the power is 200W; the magnetic field strength of the steady magnetic field is 8000Gs; the frequency of the electromagnetic oscillation field is 18HZ, and the medium and low duty cycle is 23%; the freezing temperature is -15°C and the time is 4h; the drying, grinding and screening is through a 230-mesh sieve.

[0033] Through detection, it was determined that the yield of the rubber vulcanizing agent 4,4'-dithiodimorpholine prepared by the production method of the rubber vulcanizing agent 4,4'-dithiodimorpholine was 99.58% (calculated as morpholine) and the HPLC purity was 99.87%.

[0034] Example 3

[0035] A production method of a rubber vulcanizing agent 4,4'-dithiodimorpholine comprises the following steps: adding a solvent, an acid binding agent and morpholine into a reaction kettle at the same time, stirring and mixing, controlling the temperature at 40 DEG C, dripping an oxidant while stirring, completing the dripping within 3 hours, continuing to heat-keep the reaction for 7 hours after the dripping is completed, performing a multi-energy field auxiliary treatment for 20 minutes during the heat-keep reaction, stopping stirring after the reaction is completed, filtering to remove insoluble matter, washing a filter cake with a solvent, combining the washing liquid with a filtrate to obtain a crude product solution, washing the crude product solution with water, standing for 8 minutes, releasing the lower washing water after stratification, and placing the upper 4,4'-dithiodimorpholine product solvent mixed layer into a freezing kettle for freezing, centrifugation filtering, recovering the solvent, drying, grinding and sieving the filter cake, and packaging after reaching the standard to obtain the rubber vulcanizing agent 4,4'-dithiodimorpholine.

[0036] The solvent is 120# solvent oil; the oxidant is sulfur monochloride; the mass ratio of the solvent, the acid binding agent and morpholine is 10:1.8:1; the molar ratio of the morpholine and the oxidant is 2:1; the acid binding agent is a mixture of sodium acetate, zeolite molecular sieve and quinoline in a mass ratio of 1:2:0.4; and the zeolite molecular sieve is ZSM-5 molecular sieve.

[0037] The multi-energy field includes ultrasound, a steady magnetic field and an electromagnetic oscillation field; the frequency of the ultrasound is 115kHz and the power is 220W; the magnetic field strength of the steady magnetic field is 11000Gs; the frequency of the electromagnetic oscillation field is 23HZ, and the medium and low duty cycle is 25%; the freezing temperature is -20°C and the time is 4.5h; the drying, grinding and screening is through a 250-mesh sieve.

[0038] Through detection, it was determined that the yield of the rubber vulcanizing agent 4,4'-dithiodimorpholine prepared by the production method of the rubber vulcanizing agent 4,4'-dithiodimorpholine was 99.77% (calculated as morpholine) and the HPLC purity was 99.92%.

[0039] Example 4

[0040] A production method of a rubber vulcanizing agent 4,4'-dithiodimorpholine comprises the following steps: adding a solvent, an acid binding agent and morpholine into a reaction kettle at the same time, stirring and mixing, controlling the temperature at 50 DEG C, dripping an oxidant while stirring, completing the dripping within 4 hours, continuing to heat-keep the reaction for 7.5 hours after the dripping is completed, performing a multi-energy field auxiliary treatment for 23 minutes during the heat-keep reaction, stopping stirring after the reaction is completed, filtering to remove insoluble matter, washing a filter cake with a solvent, combining the washing liquid with a filtrate to obtain a crude product solution, washing the crude product solution with water, standing for 9 minutes, releasing the lower washing water after stratification, and placing the upper 4,4'-dithiodimorpholine product solvent mixed layer into a freezing kettle for freezing, centrifugation filtering, recovering the solvent, drying, grinding and sieving the filter cake, and packaging after reaching the standard to obtain the rubber vulcanizing agent 4,4'-dithiodimorpholine.

[0041] The solvent is a mixture of n-heptane, n-hexane and 120# solvent oil in a mass ratio of 1:2:3; the oxidant is sulfur monochloride; the mass ratio of the solvent, acid binding agent and morpholine is 11:1.9:1; the molar ratio of morpholine and oxidant is 2:1; the acid binding agent is a mixture of sodium acetate, zeolite molecular sieve and quinoline in a mass ratio of 1:2.5:0.45; and the zeolite molecular sieve is ZSM-5 molecular sieve.

[0042] The multi-energy field includes ultrasound, a steady magnetic field and an electromagnetic oscillation field; the frequency of the ultrasound is 120kHz and the power is 250W; the magnetic field strength of the steady magnetic field is 12000Gs; the frequency of the electromagnetic oscillation field is 28HZ, and the medium-to-low duty cycle is 28%; the freezing temperature is -25°C and the time is 5.5h; the drying, grinding and screening is through a 290-mesh sieve.

[0043] Through detection, it was determined that the yield of the rubber vulcanizing agent 4,4'-dithiodimorpholine prepared by the production method of the rubber vulcanizing agent 4,4'-dithiodimorpholine was 99.88% (calculated as morpholine) and the HPLC purity was 99.96%.

[0044] Example 5

[0045] A production method of a rubber vulcanizing agent 4,4'-dithiodimorpholine comprises the following steps: adding a solvent, an acid binding agent and morpholine into a reaction kettle at the same time, stirring and mixing, controlling the temperature at 60 DEG C, dripping an oxidant while stirring, completing the dripping within 5 hours, continuing to heat-keep the reaction for 8 hours after the dripping is completed, performing a multi-energy field auxiliary treatment for 25 minutes during the heat-keep reaction, stopping stirring after the reaction is completed, filtering to remove insoluble matter, washing a filter cake with a solvent, combining the washing liquid with a filtrate to obtain a crude product solution, washing the crude product solution with water, standing for 10 minutes, releasing the lower washing water after stratification, and placing the upper 4,4'-dithiodimorpholine product solvent mixed layer into a freezing kettle for freezing, centrifugation filtering, recovering the solvent, drying, grinding and sieving the filter cake, and packaging after reaching the standard to obtain the rubber vulcanizing agent 4,4'-dithiodimorpholine.

[0046] The solvent is n-heptane; the oxidant is sulfur monochloride; the mass ratio of the solvent, the acid binding agent and morpholine is 12:2:1; the molar ratio of morpholine and the oxidant is 2:1; the acid binding agent is a mixture of sodium acetate, zeolite molecular sieve and quinoline in a mass ratio of 1:3:0.5; and the zeolite molecular sieve is ZSM-5 molecular sieve.

[0047] The multi-energy field includes ultrasound, a steady magnetic field and an electromagnetic oscillation field; the frequency of the ultrasound is 125kHz and the power is 260W; the magnetic field strength of the steady magnetic field is 13000Gs; the frequency of the electromagnetic oscillation field is 30HZ, and the medium and low duty cycle is 30%; the freezing temperature is -30°C and the time is 6h; the drying, grinding and screening is through a 300-mesh sieve.

[0048] Through detection, it was determined that the yield of the rubber vulcanizing agent 4,4'-dithiodimorpholine prepared by the production method of the rubber vulcanizing agent 4,4'-dithiodimorpholine was 99.94% (calculated as morpholine) and the HPLC purity was 99.97%.

[0049] Comparative Example 1

[0050] A method for producing a rubber vulcanizing agent 4,4'-dithiodimorpholine is basically the same as that of Example 1, except that there is no multi-energy field auxiliary treatment.

[0051] Through detection, it was determined that the yield of the rubber vulcanizing agent 4,4'-dithiodimorpholine prepared by the production method of the rubber vulcanizing agent 4,4'-dithiodimorpholine was 99.28% (calculated as morpholine) and the HPLC purity was 99.35%.

[0052] Comparative Example 2

[0053] A method for producing a rubber vulcanizing agent 4,4'-dithiodimorpholine is substantially the same as that of Example 1, except that the acid binding agent is anhydrous trisodium phosphate.

[0054] Through detection, it was determined that the yield of the rubber vulcanizing agent 4,4'-dithiodimorpholine prepared by the production method of the rubber vulcanizing agent 4,4'-dithiodimorpholine was 97.30% (calculated as morpholine) and the HPLC purity was 99.18%.

[0055] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the contents of the present invention and implement them accordingly. They cannot be used to limit the protection scope of the present invention. All equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for producing a rubber vulcanizing agent 4,4'-dithiodimorpholine, characterized in that: The method comprises the following steps: adding a solvent, an acid binding agent and morpholine into a reaction kettle at the same time, stirring and mixing, controlling the temperature at 20-60°C, dripping an oxidant while stirring, completing the dripping within 1-5 hours, continuing the heat preservation reaction for 6-8 hours after the dripping is completed, performing multi-energy field auxiliary treatment for 15-25 minutes during the heat preservation reaction, stopping the stirring after the reaction is completed, filtering and removing insoluble matter, washing the filter cake with a solvent, combining the washing liquid with the filtrate to obtain a crude product solution, washing the crude product solution with water, standing for 5-10 minutes, releasing the lower layer of washing water after stratification, and placing the upper layer of 4,4'-dithiodimorpholine product solvent mixed layer into a freezing kettle for freezing, centrifugal filtration, recovering the solvent, drying, grinding and sieving the filter cake, and packaging after reaching the standard to obtain a rubber vulcanizing agent 4,4'-dithiodimorpholine; the oxidant is sulfur monochloride; and the molar ratio of the morpholine to the oxidant is 2:1; The acid binding agent is a mixture of sodium acetate, zeolite molecular sieve and quinoline in a mass ratio of 1:(1-3):(0.3-0.5); the zeolite molecular sieve is ZSM-5 molecular sieve; the multi-energy field includes ultrasound, a steady magnetic field and an electromagnetic oscillation field; the frequency of the ultrasound is 95-125kHz and the power is 180-260W; the magnetic field strength of the steady magnetic field is 7000-13000Gs; the frequency of the electromagnetic oscillation field is 15-30HZ, and the medium and low duty cycle is 20-30%.

2. The method for producing the rubber vulcanizing agent 4,4'-dithiodimorpholine according to claim 1, characterized in that: The solvent is at least one of n-heptane, n-hexane and 120# solvent oil.

3. The method for producing the rubber vulcanizing agent 4,4'-dithiodimorpholine according to claim 1, characterized in that: The mass ratio of the solvent, the acid binding agent and the morpholine is (8-12):(1.5-2):

1.

4. The method for producing the rubber vulcanizing agent 4,4'-dithiodimorpholine according to claim 1, characterized in that: The freezing temperature is -10 to -30°C for 3 to 6 hours; the drying, grinding and screening are performed through a 200-300 mesh sieve.