A system and method for the production of sodium ethyl xanthate based on microchannel technology

Abstract

This invention provides a system and method for preparing sodium ethyl xanthate based on microchannel technology, belonging to the field of chemical synthesis technology. The system includes a storage tank, a metering pump, a mixing pump, a microchannel reactor, a concentration vessel, a condenser, a centrifuge, and a dryer. The method includes: mixing carbon disulfide, ethanol, and liquid alkali in a predetermined ratio via the mixing pump, then feeding the mixture into the microchannel reactor; reacting under controlled temperature and residence time conditions to generate a sodium ethyl xanthate solution; concentrating the solution by vacuum distillation in the concentration vessel; centrifuging to separate the solid product; and drying to obtain the final product. This invention improves reaction efficiency and product purity by precisely controlling reaction conditions and equipment coordination, reducing side reactions and byproduct formation, and lowering the hazards and environmental pollution of the production process. It has the advantages of high efficiency, safety, and environmental friendliness, providing an efficient solution for the industrial continuous production of sodium ethyl xanthate, and is suitable for wide application in fields such as mineral processing reagents.

Description

Technical Field

[0001] This invention relates to the field of chemical synthesis technology, and more specifically, to a system and method for preparing sodium ethyl xanthate based on microchannel technology. Background Technology

[0002] Xanthates, also known as xanthates, are important chemical substances first synthesized by Keller in 1815. They have wide applications in many fields, especially in the ore flotation industry, where their role is irreplaceable. Since xanthates were first applied to the flotation of non-ferrous metal ores in 1926, this technological breakthrough has greatly promoted the development of the flotation industry. As a key collector in the flotation process, xanthates can effectively adsorb onto the surface of metal sulfide ores, forming stable bubble-mineral particle aggregates, thereby achieving efficient separation of sulfide ores from impurity minerals. Ethyl xanthate, due to its low cost and excellent flotation performance, has always been one of the core varieties in the field of mineral processing reagents, playing an important role in the flotation of polymetallic sulfide ores such as copper, lead, and zinc.

[0003] With the rapid development of the non-ferrous metals industry, the demand for ethyl xanthate continues to grow. However, existing methods for preparing ethyl xanthate still face many problems, restricting its large-scale industrial production and widespread application. Traditional methods for preparing ethyl xanthate typically use ethanol, sodium hydroxide, and carbon disulfide as raw materials, reacting them in a kneader or batch reactor. However, these traditional methods have the following main drawbacks:

[0004] Severe environmental pollution: Traditional processes easily generate large amounts of waste liquid and volatile harmful gases, such as carbon disulfide and other sulfur-containing compounds, which are difficult to treat and extremely harmful to the environment. Furthermore, production under closed conditions cannot completely prevent the escape of harmful substances, posing a threat to the safety of operators.

[0005] Numerous side reactions and byproducts: Traditional processes have low reaction efficiency, frequently resulting in side reactions and a high proportion of byproducts. This not only reduces the purity of the target product, sodium ethyl xanthate, but also increases the difficulty of separation and purification, raising production costs. Unstable product quality: Due to poor controllability of the reaction process and limited mass and heat transfer, traditional methods struggle to guarantee product quality stability, leading to significant fluctuations in purity and content between different batches, failing to meet the high-purity xanthate requirements of modern flotation processes. Low production efficiency: Kneaders or batch reactors, due to their inefficient mass and heat transfer performance, result in slow reaction rates and long reaction times, leading to low overall production efficiency. This not only increases energy consumption but also limits the expansion of production scale. Poor safety: The preparation of ethyl xanthate involves volatile and highly toxic raw materials such as carbon disulfide. In traditional processes, due to equipment limitations and lag in process control, fires, explosions, and other safety accidents are highly likely, resulting in high process risks.

[0006] To overcome the aforementioned problems, some studies in recent years have proposed new processes such as solvent methods and aqueous solution methods. These new methods attempt to reduce pollutant emissions and improve product purity by improving reaction conditions and optimizing process flows. However, these methods have not fundamentally solved the existing problems, specifically manifested in the following ways: Byproduct issues remain prominent: While solvent and aqueous solution methods reduce environmental pollution to some extent, numerous side reactions still occur during the reaction process, especially carbon disulfide byproducts, which are difficult to control, making it difficult to further improve product purity; Increased process complexity: Some improved methods introduce multi-step reaction processes and complex separation and purification steps, which not only increases the complexity of equipment and operations but also further increases production costs; Insufficient continuous and large-scale production capacity: Traditional processes and some improved processes rely on batch reactors, resulting in low levels of continuous and automated reaction processes, making it difficult to meet the needs of large-scale industrial production.

[0007] In summary, existing methods for preparing ethyl xanthate have significant shortcomings in terms of environmental friendliness, product quality stability, reaction efficiency, and safety, failing to meet the demands of modern production for efficient, environmentally friendly, and safe processes. Therefore, a novel technological solution is urgently needed to optimize reactor design and process flow, thereby improving product quality and purity while reducing environmental pollution and process risks, ultimately achieving efficient, green, and continuous production of sodium ethyl xanthate. Summary of the Invention

[0008] One of the technical problems to be solved by the present invention is to provide a system for preparing sodium ethyl xanthate based on microchannel technology, so as to solve the problems of large environmental pollution, low reaction efficiency, many reaction by-products and insufficient operational safety of the existing technology.

[0009] To overcome the shortcomings of the prior art, the present invention provides a system for preparing sodium ethyl xanthate based on microchannel technology, the system comprising the following parts:

[0010] The first storage tank, the second storage tank, and the third storage tank are used to store the reaction raw materials carbon disulfide, ethanol, and liquid alkali, respectively.

[0011] Mixing pump: The input end of the mixing pump is connected to the output end of the first storage tank, the second storage tank and the third storage tank, and is used to mix carbon disulfide, ethanol and liquid alkali;

[0012] Microchannel reactor: The input end of the microchannel reactor is connected to the output end of the mixing pump to receive the mixed reaction raw materials and react them at a set temperature and residence time to generate sodium ethyl xanthate solution;

[0013] Concentration vessel: The input end of the concentration vessel is connected to the output end of the microchannel reactor, and is used to concentrate the sodium ethyl xanthate solution generated by the reaction in the microchannel reactor by vacuum distillation. The concentration vessel is equipped with a recovery output end and a product output end.

[0014] Condenser: The input end of the condenser is connected to the recovery output end of the concentration vessel, and is used to recover unreacted raw materials and by-products;

[0015] Centrifuge: The input end of the centrifuge is connected to the product output end of the concentration vessel, and is used to separate the concentrated sodium ethyl xanthate;

[0016] Dryer: The input end of the dryer is connected to the output end of the centrifuge, and it is used to dry the separated sodium ethyl xanthate to obtain the final product.

[0017] This invention provides a system for preparing sodium ethyl xanthate based on microchannel technology. Utilizing the efficient mass and heat transfer characteristics of microchannel reactors, the system enables the reactants to undergo rapid and uniform chemical reactions at a microscale, minimizing side reactions. Through continuous system design, the entire preparation process is smooth and stable, with increased reaction rates. The purity and yield of sodium ethyl xanthate are significantly superior to traditional techniques, resulting in more stable product quality, higher system safety, and reduced environmental impact. Compared to existing technologies, this system offers the following advantages:

[0018] Highly efficient mass and heat transfer: The system of this invention employs a microchannel reactor, whose microscale structure significantly improves the efficiency of mass and heat transfer during the reaction process, thereby greatly shortening the reaction time and increasing the reaction rate. Simultaneously, the precise control capability of the microchannels avoids local overheating and side reactions, thus reducing byproduct formation and improving product purity. Continuous production and stability: The system of this invention adopts a modular system design, enabling continuous operation of reaction, concentration, separation, and drying, avoiding the instability caused by frequent switching in traditional batch processes. Furthermore, the synergistic effect of each unit ensures the overall high efficiency and stability of the system, making it particularly suitable for industrial production. Environmentally friendly and high resource utilization: The system of this invention recovers unreacted raw materials and byproducts through a condenser, enabling resource recycling and reducing resource waste and environmental pollution. The vacuum distillation process effectively removes water and unreacted raw materials generated during the reaction, further improving product yield. High operational safety: The microchannel reactor used in the system... Its internal reaction space is small, and its unique structural design reduces the accumulation of reactants, fundamentally reducing the risk of reaction. At the same time, the entire system operates under closed conditions, reducing the harm of volatile and toxic raw materials to operators and the environment, and greatly improving operational safety.

[0019] In one possible implementation, the output ends of the first, second, and third storage tanks are respectively connected to the first, second, and third metering pumps, respectively, and the output ends of the first, second, and third metering pumps are connected to the input end of the mixing pump. The output end of the condenser is connected to a receiving tank.

[0020] Compared with existing technologies, the above technical solution, by introducing independent metering pumps between the storage tank and the mixing pump and achieving one-to-one connection, can accurately control the dosage of each raw material, while avoiding cross-contamination and unstable flow during the raw material transportation process. The application of metering pumps optimizes the supply method of reaction raw materials. Through stable and accurate raw material ratios and continuous feeding, the uniformity and rate of the reaction are improved, ensuring that subsequent reaction stages can be completed under optimal conditions. The material condensed by the condenser is temporarily stored in the receiving tank.

[0021] Another technical problem to be solved by the present invention is to provide a method for preparing sodium ethyl xanthate based on microchannel technology, so as to solve the problems of low reaction efficiency, low product purity, many by-products and serious waste of raw materials in the existing technology.

[0022] To overcome the shortcomings of the prior art, the present invention provides a method for preparing sodium ethyl xanthate based on microchannel technology. The method is implemented using the aforementioned system and includes the following steps:

[0023] S1: Raw material preparation and transportation: Carbon disulfide, ethanol and liquid alkali are stored in the first storage tank, the second storage tank and the third storage tank respectively, and transported to the mixing pump according to the preset molar equivalent ratio, and are initially mixed in the mixing pump;

[0024] S2: Microchannel reaction: The raw materials mixed in step S1 are fed into a microchannel reactor. The reaction temperature and reaction residence time in the microchannel reactor are controlled so that carbon disulfide, ethanol and liquid alkali react in the microchannel to generate sodium ethyl xanthate solution.

[0025] S3: Concentration treatment: The sodium ethyl xanthate solution generated in step S2 is output from the microchannel reactor to the concentration vessel, and distilled and concentrated under reduced pressure. Unreacted raw materials and by-products are discharged from the recovery output end of the concentration vessel and recovered through a condenser. At the same time, the concentrated sodium ethyl xanthate solution is discharged from the product output end of the concentration vessel.

[0026] S4: Centrifugation: The concentrated sodium ethyl xanthate solution from step S3 is fed into a centrifuge to separate the sodium ethyl xanthate solid and the by-product liquid.

[0027] S5: Drying treatment: The sodium ethyl xanthate solid separated by the centrifuge in step S4 is sent to a dryer and dried under controlled drying conditions to obtain the final sodium ethyl xanthate product.

[0028] This application discloses a method for preparing sodium ethyl xanthate based on microchannel technology. By employing microchannel reactor technology, it overcomes the shortcomings of traditional processes, such as low reaction efficiency, low product purity, numerous by-products, and significant raw material waste. This method achieves efficient, safe, and continuous preparation of sodium ethyl xanthate, providing a low-cost, high-efficiency, and environmentally friendly production process for related industries. Compared with existing technologies, it has the following advantages:

[0029] Significantly improved reaction efficiency: This method uses a microchannel reactor instead of a traditional reaction vessel, allowing the mixed reaction of carbon disulfide, ethanol, and liquid alkali to proceed in the microscale environment of the microchannel. The microchannel has an extremely high surface area-to-volume ratio, thus significantly improving the mass and heat transfer efficiency of the reaction, ensuring that the reaction can be completed fully in a shorter time, and greatly shortening the reaction time.

[0030] Higher product purity: Thanks to the precise control of raw material ratio and the high uniformity of microchannel reaction, the occurrence of side reactions is effectively suppressed and the amount of by-products is significantly reduced, resulting in a significant improvement in the purity of the final sodium ethyl xanthate product compared with traditional processes.

[0031] Continuous production for stable processes: Traditional methods are mostly batch operations, while this method achieves continuous reaction through microchannel technology, significantly improving the stability and consistency of the production process. Through continuous raw material delivery, continuous reaction, and downstream processing, large-scale continuous industrial production can be achieved, while avoiding the process fluctuations problems of batch operations.

[0032] Green and environmentally friendly with high resource utilization: During the concentration process, this method recovers unreacted raw materials and by-products discharged from the output end, which can be reused after being recovered by the condenser, greatly improving the utilization rate of raw materials, reducing raw material waste, and reducing waste emissions, making it more environmentally friendly.

[0033] High operational safety: The small reaction volume within the microchannel reactor reduces the potential safety risks associated with reactions involving highly hazardous raw materials (such as carbon disulfide). Even under abnormal conditions, the amount of hazardous substances is limited to extremely low levels, fundamentally improving the safety of the reaction.

[0034] High controllability: By precisely controlling the temperature, residence time, and liquid flow rate of the microchannel reactor, reaction conditions can be precisely adjusted, making the production process more controllable and thus further improving the stability of product quality;

[0035] Highly adaptable and suitable for production of different scales: This method is not only applicable to laboratory-scale research, but can also be scaled up for industrial production through modular design, thereby meeting the needs of production of different scales.

[0036] In one possible implementation, in step S1, the liquid alkali is sodium hydroxide, and the concentration of the sodium hydroxide is 30-50%.

[0037] Compared with existing technologies, the above-mentioned technical solution, by optimizing the concentration range of the liquid alkali (30-50%), ensures the activity and sufficiency of sodium hydroxide in the reaction, while avoiding the surge of side reactions caused by excessively high concentrations or the incomplete reaction caused by excessively low concentrations. This directly improves the formation efficiency and purity of the target product. Simultaneously, the above concentration range ensures the long-term operation of the microchannel device and reduces the risks of alkaline corrosion and heat accumulation.

[0038] In one possible implementation, in step S1, the molar equivalent ratio of carbon disulfide, ethanol and liquid alkali is 1:(1-1.1):(1-1.1).

[0039] Compared to existing technologies, the above-mentioned technical solution, by slightly adjusting the molar equivalent ratio of ethanol and liquid alkali to 1-1.1 times that of carbon disulfide, ensures the full utilization of carbon disulfide during the reaction, thus avoiding incomplete reactions due to insufficient carbon disulfide. Simultaneously, excess ethanol and liquid alkali can quickly capture potential side reaction intermediates, such as disulfides or unreacted carbon sulfides, thereby reducing the formation of byproducts. Furthermore, precise ratio settings can be further optimized through the flow rate and residence time of the microchannel reactor, ultimately ensuring both high-efficiency conversion and the purity and yield of the target product. This not only reduces raw material waste and environmental burden but also significantly improves the overall economic and environmental performance of the process.

[0040] In one possible implementation, in step S1, the molar equivalent ratio of carbon disulfide, ethanol, and liquid alkali is 1:1.05:1.05.

[0041] Compared with existing technologies, the above technical solution optimizes the molar equivalent ratio of carbon disulfide, ethanol, and liquid alkali to 1:1.05:1.05, further improving the yield and purity of sodium ethyl xanthate. This results in more stable performance and consistent quality of the final product. Furthermore, by optimizing the molar equivalent ratio of the raw materials and slightly increasing the proportion of ethanol and liquid alkali, the formation of reaction intermediates and byproducts can be effectively reduced while ensuring the complete reaction of carbon disulfide. This avoids the difficulty in separation and purification caused by excessive byproducts in subsequent operations.

[0042] In one possible implementation, in step S2, the reaction temperature is 0-45°C and the reaction residence time is 1-240 min.

[0043] Compared with existing technologies, the above-mentioned technical solution, by setting a wide range of reaction temperatures from 0-45℃ and residence times from 1-240 minutes, can optimize the reaction process for different process conditions and raw material states, ensuring the applicability and efficiency of the system and maximizing its adaptability to process requirements under different reaction conditions. At lower temperatures and shorter times, it can effectively suppress the occurrence of heat-sensitive side reactions; while at higher temperatures and longer times, it can accelerate the reaction rate and promote the complete conversion of carbon disulfide, ethanol, and liquid alkali. The precise temperature control capability and adjustable residence time of the microchannel reactor in this technical solution further enhance the above effects, thereby realizing a highly efficient and stable process for the synthesis of sodium ethyl xanthate, solving the problems of low yield and high energy consumption caused by inflexible or limited reaction conditions in existing technologies.

[0044] In one possible implementation, in step S2, the reaction temperature is 25-30°C and the reaction residence time is 220 min.

[0045] Compared with existing technologies, the above-mentioned technical solution provides sufficient activation energy for the reaction of carbon disulfide, ethanol and liquid alkali by selecting the optimal temperature range of 25-30℃ for reaction activation, while avoiding the generation of impurities caused by side reactions in traditional high-temperature reactions. The 220-minute reaction time ensures that the raw materials remain in the microchannel for a sufficient period of time, so that the contact efficiency and mass transfer effect between reactants are optimized. The high efficiency of mass transfer and temperature control of the microchannel reactor in this invention further enhances this effect, which not only enables the reaction to be completed at a lower temperature, but also ensures the high purity and high yield of the product.

[0046] In one possible implementation, in step S2, the hydraulic diameter within the microchannel reactor is 100-6000 micrometers.

[0047] Compared with existing technologies, the above-mentioned technical solution, using a hydraulic diameter range of 100-6000 micrometers, fully demonstrates the high efficiency and controllability of microscale reactors. The smaller hydraulic diameter allows reactants to form high turbulence and short mixing time in the channel, improving mass transfer efficiency and reaction rate. The larger hydraulic diameter, on the other hand, facilitates the industrial processing of high-flow-rate materials and avoids clogging problems caused by excessively narrow channels. Compared with traditional reactors, the above-mentioned technical solution of this invention, through the rational design of the hydraulic diameter range, ensures flexible switching between small-batch fine production and large-scale industrial applications, which not only improves the completeness of the reaction but also reduces the risks in process operation.

[0048] In one possible implementation, in step S2, the reaction formula of the microchannel reaction is: C2H5OH+NaOH+CS2→C2H5OHCSSNa+H2O.

[0049] Compared with existing technologies, the above-mentioned technical solution, through a clearly defined chemical reaction design (C2H5OH+NaOH+CS2→C2H5OCSSNa+H2O), combined with the highly efficient mass and heat transfer performance of the microchannel technology in this invention, ensures that the reactants complete the formation of the target product in the shortest time and at the optimal ratio, while avoiding the multi-step reaction and side reaction problems in traditional processes. The advantages of microchannel reactors in temperature and time control further guarantee the controllability and selectivity of the reaction, enabling the efficient and continuous production of sodium ethyl xanthate. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the system for preparing sodium ethyl xanthate based on microchannel technology in this invention; Figure 1In the middle: 1. First storage tank, 2. Second storage tank, 3. Third storage tank, 4. First metering pump, 5. Second metering pump, 6. Third metering pump, 7. Mixing pump, 8. Microchannel reactor, 9. Concentrator, 10. Condenser, 11. Centrifuge, 12. Dryer, 13. Receiving tank; 14. Recovery output end; 15. Product output end.

[0051] Figure 2 The infrared spectra (FT-IR) of sodium ethyl xanthate prepared in this invention and purified sodium ethyl xanthate of industrial grade are shown. Detailed Implementation

[0052] First, those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the embodiments of this application and are not intended to limit the scope of protection of the embodiments of this application. Those skilled in the art can make adjustments as needed to adapt to specific application scenarios.

[0053] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0054] like Figure 1 As shown, this invention provides a system for preparing sodium ethyl xanthate based on microchannel technology, the system comprising the following parts:

[0055] Storage tank 1, storage tank 2, and storage tank 3 are used to store the reaction raw materials carbon disulfide, ethanol, and liquid alkali, respectively.

[0056] Mixing pump 7: The input end of mixing pump 7 is connected to the output ends of the first storage tank 1, the second storage tank 2 and the third storage tank 3, and is used to mix carbon disulfide, ethanol and liquid alkali;

[0057] Microchannel reactor 8: The input end of microchannel reactor 8 is connected to the output end of mixing pump 7 to receive the mixed reaction raw materials and react them at a set temperature and residence time to generate sodium ethyl xanthate solution.

[0058] Concentration vessel 9: The input end of the concentration vessel 9 is connected to the output end of the microchannel reactor 8, and is used to concentrate the sodium ethyl xanthate solution generated by the reaction in the microchannel reactor 8 by vacuum distillation. The concentration vessel 9 is equipped with a recovery output end 14 and a product output end 15.

[0059] Condenser 10: The input end of condenser 10 is connected to the recovery output end 14 of concentration vessel 9, and is used to recover unreacted raw materials and by-products;

[0060] Centrifuge 11: The input end of centrifuge 11 is connected to the product output end 15 of the concentration vessel 9, and is used to separate the concentrated sodium ethyl xanthate.

[0061] Dryer 12: The input end of dryer 12 is connected to the output end of centrifuge 11 and is used to dry the separated sodium ethyl xanthate to obtain the final product.

[0062] As a preferred embodiment, the output ends of the first storage tank 1, the second storage tank 2, and the third storage tank 3 are respectively connected to the first metering pump 4, the second metering pump 5, and the third metering pump 6 in a one-to-one correspondence. The output ends of the first metering pump 4, the second metering pump 5, and the third metering pump 6 are connected to the input end of the mixing pump 7. The output end of the condenser 10 is connected to a receiving tank 13.

[0063] This invention also provides a method for preparing sodium ethyl xanthate based on microchannel technology, implemented through the above-described system, with the flow direction as follows: Figure 1 As shown, it includes the following steps:

[0064] S1: Raw material preparation and transportation: Carbon disulfide, ethanol and liquid alkali are stored in the first storage tank 1, the second storage tank 2 and the third storage tank 3 respectively, and transported to the mixing pump 7 according to the preset molar equivalent ratio, and are initially mixed in the mixing pump 7.

[0065] S2: Microchannel reaction: The raw materials mixed in step S1 are fed into microchannel reactor 8. The reaction temperature and reaction residence time in microchannel reactor 8 are controlled so that carbon disulfide, ethanol and liquid alkali react in the microchannel to generate sodium ethyl xanthate solution.

[0066] S3: Concentration treatment: The sodium ethyl xanthate solution generated in step S2 is output from the microchannel reactor 8 to the concentration vessel 9, and distilled and concentrated under reduced pressure. Unreacted raw materials and by-products are discharged from the recovery output end 14 of the concentration vessel 9 and recovered through the condenser 10. At the same time, the concentrated sodium ethyl xanthate solution is discharged from the product output end 15 of the concentration vessel 9.

[0067] S4: Centrifugation: The concentrated sodium ethyl xanthate solution from step S3 is fed into centrifuge 11, and the sodium ethyl xanthate solid and by-product liquid are separated by centrifuge 11.

[0068] S5: Drying treatment: The sodium ethyl xanthate solid separated by centrifuge 11 in step S4 is sent to dryer 12 and dried under controlled drying conditions to obtain the final sodium ethyl xanthate product.

[0069] As a preferred embodiment, in step S1, the liquid alkali is sodium hydroxide, and the concentration of the sodium hydroxide is 30-50%.

[0070] As a preferred embodiment, in step S1, the molar equivalent ratio of carbon disulfide, ethanol and liquid alkali is 1:(1-1.1):(1-1.1).

[0071] As a preferred embodiment, in step S1, the molar equivalent ratio of carbon disulfide, ethanol, and liquid alkali is 1:1.05:1.05.

[0072] As a preferred embodiment, in step S2, the reaction temperature is 25-30℃ and the reaction residence time is 220min.

[0073] As a preferred embodiment, in step S2, the reaction temperature is 0-45℃ and the reaction residence time is 1-240min.

[0074] As a preferred embodiment, in step S2, the hydraulic diameter of the microchannel reactor is 100-6000 micrometers.

[0075] As a preferred embodiment, in step S2, the reaction formula for the microchannel reaction is:

[0076] C2H5OH+NaOH+CS2→C2H5OCSSNa+H2O.

[0077] The system and method of this invention, through close cooperation, demonstrate a high degree of synergy, thereby achieving the goal of preparing high-yield, high-purity sodium ethyl xanthate. Specifically, the system and method of this invention form a unique synergistic effect in the following aspects:

[0078] 1. Synergistic effect of efficient mass transfer and reaction control

[0079] The microchannel reactor of this invention, through its unique microscale structure and high mass and heat transfer efficiency, forms a close working relationship with the mixing pump system and the metering pump system. The metering pump system ensures that carbon disulfide, ethanol, and liquid alkali are uniformly delivered to the mixing pump at an accurate molar equivalent ratio. The mixing pump performs the initial, efficient mixing operation, laying the foundation for a uniform distribution of reactants entering the microchannel reactor. Meanwhile, the efficient reaction conditions of the microchannel reactor (controllable temperature, residence time, and reaction channel design) guarantee sufficient contact and selective reaction between reactants, thereby avoiding localized overheating and side reactions. This system collaboration significantly improves the conversion rate of carbon disulfide, ethanol, and liquid alkali, while ensuring the high purity of the generated sodium ethyl xanthate.

[0080] 2. The synergistic effect of precise control and efficient separation

[0081] In the preparation of high-purity sodium ethyl xanthate, the system's concentration vessel, condenser, and centrifuge form a highly efficient collaborative working relationship. The concentration vessel, under reduced pressure distillation conditions, separates unreacted raw materials and byproducts from the reaction solution and discharges them to the condenser for recovery. The product output is a concentrated sodium ethyl xanthate solution. This precise separation effectively preserves the high purity of the target product, reduces interference from unreacted raw materials and byproducts to subsequent processes, and achieves efficient resource utilization and byproduct recovery, thereby reducing the overall energy consumption and waste disposal costs.

[0082] 3. Synergistic effect of continuous reaction and efficient drying

[0083] By combining the functions of a centrifuge and a dryer, this invention achieves the efficient conversion of the target product, sodium ethyl xanthate, from a solution to a solid state. The centrifuge separates the target product from the liquid byproducts in the concentrate, while the dryer further dries the solid sodium ethyl xanthate obtained by centrifugation. This system effectively avoids the quality loss caused by insufficient or excessive drying in traditional processes, while optimizing drying conditions to ensure product purity and yield.

[0084] 4. Dynamic matching and optimization between systems and methods

[0085] The system and method of this invention are complementary in design. Through dynamic matching of system hardware (including the precise design of the microchannel reactor) and process methods (including optimized molar equivalent ratio, reaction temperature, and residence time), a significant synergistic effect is achieved, specifically including:

[0086] System optimization and coordination method: The coordination between the microchannel reactor and the concentration vessel in the system allows the byproducts generated by the reaction to be efficiently distilled out, avoiding the impact of the accumulation of byproducts on the purity of the target product;

[0087] The method has a reverse effect on the system: optimized reaction conditions (such as a temperature of 25-30℃ and a raw material molar equivalent ratio of 1:1.05:1.05) improve the operating efficiency of the equipment (microchannel reactor) in the system, so that the yield and purity of the final product are both optimal.

[0088] Through the synergistic effect of the above systems and methods, this invention achieves the following technical advantages: High yield and high purity: The yield of sodium ethyl xanthate reaches over 90%, and the purity can reach over 95%, far exceeding that of traditional processes; High efficiency, environmental protection, and continuous production: The design of the system and methods reduces energy consumption and raw material waste, realizing continuous and automated production from raw material input to final product output, significantly improving production efficiency, while reducing by-product emissions, meeting the high environmental protection requirements of modern industry; Safety and stability: The high-efficiency mass and heat transfer performance of the microchannel reactor avoids the instability of reaction conditions and local overheating, greatly improving the safety of the process.

[0089] In summary, the system and method of this invention work together to form a highly efficient and selective process chain from raw materials to finished products through synergistic effects in reaction control, separation and purification, and drying. This synergistic mechanism not only achieves high yield and high purity of sodium ethyl xanthate, but also reduces production costs and improves the safety and environmental performance of the process, providing a brand-new solution for industrial production.

[0090] The following, in conjunction with the above-described scope of technical solutions, provides specific embodiments incorporating data to further elaborate on the technical solutions of the present invention:

[0091] Example 1:

[0092] This embodiment provides a system and method for preparing sodium ethyl xanthate based on microchannel technology. The system includes: a storage tank system, a metering pump system, a mixing pump 7, a microchannel reactor 8, a concentration vessel 9, a condenser 10, a centrifuge 11, and a dryer 12, with their corresponding positions and functions as follows:

[0093] Tank System: The system consists of three independent tanks: Tank 1, Tank 2, and Tank 3, used for storing carbon disulfide, ethanol, and liquid alkali, respectively. The outlet of each tank is connected to a corresponding metering pump via pipeline for conveying the raw materials.

[0094] Metering pump system: Each of the above-mentioned storage tanks corresponds to a metering pump, which includes a first metering pump 4, a second metering pump 5 and a third metering pump 6, which are used for the quantitative delivery of carbon disulfide, ethanol and liquid alkali, respectively. The metering pumps are connected to the subsequent mixing pump 7 through pipelines to ensure that the raw materials are delivered in the set proportion.

[0095] Mixing pump 7: Carbon disulfide, ethanol and liquid alkali output from the metering pump are fed into mixing pump 7 through pipelines. Mixing pump 7 performs preliminary mixing of raw materials and transports the mixed raw materials to microchannel reactor 8.

[0096] Microchannel reactor 8: The output end of the mixing pump 7 is connected to the input end of the microchannel reactor 8. The microchannel reactor 8 is equipped with microscale reaction channels to improve the mass and heat transfer efficiency of the reaction. The reactor can control the temperature and residence time to ensure that carbon disulfide, ethanol and liquid alkali react fully to generate sodium ethyl xanthate solution.

[0097] Concentrator 9: The output end of the microchannel reactor 8 is connected to the concentration vessel 9, which is used to receive the sodium ethyl xanthate solution and concentrate it by distillation under reduced pressure. The concentration vessel 9 has two output ends, one of which is the recovery output end 14, used to discharge unreacted raw materials and by-products; the other end is the product output end 15, used to discharge the concentrated sodium ethyl xanthate solution.

[0098] Condenser 10: The input end of condenser 10 is connected to the recovery output end 14 of concentration vessel 9. Condenser 10 cools and recovers the discharged unreacted raw materials and by-products to ensure the effective utilization of materials. Its output end is connected to receiving tank 13 to store unreacted raw materials and by-products.

[0099] Centrifuge 11: The product output end 15 of the concentration vessel 9 is connected to the centrifuge 11 through a pipeline. The centrifuge 11 is used to receive the concentrated sodium ethyl xanthate solution and separate the sodium ethyl xanthate solid and the by-product liquid through centrifugation.

[0100] Dryer 12: The outlet end of centrifuge 11 is connected to dryer 12, which is used to receive the separated sodium ethyl xanthate solid and dry it to obtain the final sodium ethyl xanthate product.

[0101] The method for preparing sodium ethyl xanthate based on microchannel technology is implemented using the above system and includes the following steps:

[0102] S1: Raw material preparation and transportation

[0103] Carbon disulfide is stored in the first storage tank 1, ethanol is stored in the second storage tank 2, and liquid alkali (40% sodium hydroxide solution) is stored in the third storage tank 3. Carbon disulfide is delivered to the mixing pump 7 through the first metering pump 4, ethanol through the second metering pump 5, and liquid alkali through the third metering pump 6, respectively. The feed molar equivalent ratio of the metering pump is controlled to be 1:1.05:1. The three raw materials are initially mixed by the mixing pump 7.

[0104] S2: Microchannel reaction

[0105] The mixed raw materials in step S1 are fed into microchannel reactor 8. The reaction temperature in microchannel reactor 8 is controlled at 5℃~10℃ and the reaction residence time is 95 minutes, so that carbon disulfide, ethanol and liquid alkali react in the microchannel to generate sodium ethyl xanthate solution.

[0106] S3: Concentration Process

[0107] The sodium ethyl xanthate solution generated in step S2 is conveyed from the output end of the microchannel reactor 8 to the concentration vessel 9 (9) for distillation and concentration under reduced pressure. Unreacted raw materials and by-products are discharged through the recovery output end 14 of the concentration vessel 9 and conveyed to the condenser 10 for recovery and treatment; the concentrated sodium ethyl xanthate solution is discharged through the product output end 15 of the concentration vessel 9.

[0108] S4: Centrifugal separation

[0109] The concentrated sodium ethyl xanthate solution from step S3 is fed into centrifuge 11, and sodium ethyl xanthate solid and by-product liquid are obtained by centrifugation.

[0110] S5: Drying process

[0111] The sodium ethyl xanthate solid obtained by centrifugation in step S4 is fed into dryer 12 and dried under appropriate drying conditions to finally obtain sodium ethyl xanthate product.

[0112] Product performance:

[0113] The yield and purity of the sodium ethyl xanthate product obtained in step S5 were determined. The yield of the final product was 95.50%. The purity of the product was 96.2% by titration analysis according to YS / T 271-1994 standard.

[0114] Example 2:

[0115] The system used in Example 2 is the same as that in Example 1, and the method is as follows:

[0116] S1: Raw material preparation and transportation

[0117] Carbon disulfide is stored in the first storage tank 1, ethanol is stored in the second storage tank 2, and liquid alkali (40% sodium hydroxide solution) is stored in the third storage tank 3. Carbon disulfide is delivered to the mixing pump 7 via the first metering pump 4, ethanol via the second metering pump 5, and liquid alkali via the third metering pump 6. The feed molar equivalent ratio of the metering pumps is controlled to be 1:1.05:1.05. The three raw materials are initially mixed using the mixing pump 7.

[0118] S2: Microchannel reaction

[0119] The mixed raw materials from step S1 are fed into microchannel reactor 8. The reaction temperature inside microchannel reactor 8 is controlled at 25℃~30℃ and the reaction residence time is 220 minutes, so that carbon disulfide, ethanol and liquid alkali react in the microchannel to generate sodium ethyl xanthate solution.

[0120] S3: Concentration Process

[0121] The sodium ethyl xanthate solution generated in step S2 is conveyed from the output of the microchannel reactor 8 to the concentration vessel 9 for distillation and concentration under reduced pressure. Unreacted raw materials and byproducts are discharged through the recovery output 14 of the concentration vessel 9 and sent to the condenser 10 for recovery and treatment; the concentrated sodium ethyl xanthate solution is discharged through the product output 15 of the concentration vessel 9.

[0122] S4: Centrifugal separation

[0123] The concentrated sodium ethyl xanthate solution from step S3 is fed into centrifuge 11, and sodium ethyl xanthate solid and by-product liquid are obtained by centrifugation.

[0124] S5: Drying process

[0125] The sodium ethyl xanthate solid obtained by centrifugation in step S4 is fed into dryer 12 and dried under appropriate drying conditions to finally obtain sodium ethyl xanthate product.

[0126] Product performance:

[0127] The yield and purity of the sodium ethyl xanthate product obtained in step S5 were determined. The yield of the final product was 96.30%, and the purity of the product was 97.1% according to the YS / T 271-1994 standard titration analysis.

[0128] Example 3:

[0129] The system used in Example 3 is the same as that in Example 1, and the method is as follows:

[0130] S1: Raw material preparation and transportation

[0131] Carbon disulfide is stored in the first storage tank 1, ethanol is stored in the second storage tank 2, and liquid alkali (50% sodium hydroxide solution) is stored in the third storage tank 3. Carbon disulfide is delivered to the mixing pump 7 via the first metering pump 4, ethanol via the second metering pump 5, and liquid alkali via the third metering pump 6. The feed molar equivalent ratio of the metering pumps is controlled to be 1:1.1:1.1. The three raw materials are initially mixed using the mixing pump 7.

[0132] S2: Microchannel reaction

[0133] The mixed raw materials from step S1 are fed into microchannel reactor 8. The reaction temperature inside microchannel reactor 8 is controlled at 0°C and the reaction residence time is 240 minutes, so that carbon disulfide, ethanol and liquid alkali react in the microchannel to generate sodium ethyl xanthate solution.

[0134] S3: Concentration Process

[0135] The sodium ethyl xanthate solution generated in step S2 is conveyed from the output of the microchannel reactor 8 to the concentration vessel 9 for distillation and concentration under reduced pressure. Unreacted raw materials and byproducts are discharged through the recovery output 14 of the concentration vessel 9 and sent to the condenser 10 for recovery and treatment; the concentrated sodium ethyl xanthate solution is discharged through the product output 15 of the concentration vessel 9.

[0136] S4: Centrifugal separation

[0137] The concentrated sodium ethyl xanthate solution from step S3 is fed into centrifuge 11, and sodium ethyl xanthate solid and by-product liquid are obtained by centrifugation.

[0138] S5: Drying process

[0139] The sodium ethyl xanthate solid obtained by centrifugation in step S4 is fed into dryer 12 and dried under appropriate drying conditions to finally obtain sodium ethyl xanthate product.

[0140] Product performance:

[0141] The yield and purity of the sodium ethyl xanthate product obtained in step S5 were determined. The yield of the final product was 93.20%, and the purity of the product was 94.8% according to the YS / T 271-1994 standard titration analysis.

[0142] Example 4:

[0143] The system used in Example 4 is the same as that in Example 1, and the method is as follows:

[0144] S1: Raw material preparation and transportation

[0145] Carbon disulfide is stored in the first storage tank 1, ethanol is stored in the second storage tank 2, and liquid alkali (30% sodium hydroxide solution) is stored in the third storage tank 3. Carbon disulfide is delivered to the mixing pump 7 through the first metering pump 4, ethanol through the second metering pump 5, and liquid alkali through the third metering pump 6, respectively. The feed molar equivalent ratio of the metering pump is controlled to be 1:1:1. The three raw materials are initially mixed by the mixing pump 7.

[0146] S2: Microchannel reaction

[0147] The mixed raw materials from step S1 are fed into microchannel reactor 8. The reaction temperature inside microchannel reactor 8 is controlled at 45°C and the reaction residence time is 1 minute, so that carbon disulfide, ethanol and liquid alkali react in the microchannel to generate sodium ethyl xanthate solution.

[0148] S3: Concentration Process

[0149] The sodium ethyl xanthate solution generated in step S2 is conveyed from the output of the microchannel reactor 8 to the concentration vessel 9 for distillation and concentration under reduced pressure. Unreacted raw materials and byproducts are discharged through the recovery output 14 of the concentration vessel 9 and sent to the condenser 10 for recovery and treatment; the concentrated sodium ethyl xanthate solution is discharged through the product output 15 of the concentration vessel 9.

[0150] S4: Centrifugal separation

[0151] The concentrated sodium ethyl xanthate solution from step S3 is fed into centrifuge 11, and sodium ethyl xanthate solid and by-product liquid are obtained by centrifugation.

[0152] S5: Drying process

[0153] The sodium ethyl xanthate solid obtained by centrifugation in step S4 is fed into dryer 12 and dried under appropriate drying conditions to finally obtain sodium ethyl xanthate product.

[0154] Product performance:

[0155] The yield and purity of the sodium ethyl xanthate product obtained in step S5 were determined. The yield of the final product was 90.50%, and the purity of the product was 93.5% according to the YS / T 271-1994 standard titration analysis.

[0156] Product Validation:

[0157] Take 10g of industrial ethyl xanthate and place it in an Erlenmeyer flask; then add 20g of anhydrous ethanol, mix thoroughly, and a white precipitate will appear at the bottom of the flask; prepare a Buchner funnel and filter paper, adjust the vacuum pump to a suitable vacuum level; open the stopper on the filter flask and pour the mixed solution to be filtered into the Buchner funnel; turn on the vacuum pump, and use the vacuum suction to filter the filtrate through the upper filter paper Buchner funnel into the lower suction flask; after filtration, turn off the vacuum pump and remove the suction flask. The solution obtained by suction filtration is concentrated, dried, and crystallized by vacuum rotary evaporation to obtain a relatively pure ethyl xanthate product, and its infrared spectrum is measured, such as... Figure 2 As shown.

[0158] Similarly, the infrared spectra of the products obtained in Examples 1-4 of the present invention were measured, such as... Figure 2 As shown; by Figure 2 Analysis shows that the characteristic peak of C=S is a strong peak at 1700-1500 cm⁻¹. -1 Between 16 and 18cm -1 The peak is a C=S vibration peak, proving the existence of C=S, with moderate intensity; 1280~1100cm -1 The interval peak corresponds to COC, 1174 cm⁻¹ in the figure. -1The peak at 1042 cm⁻¹ should be COC. -1 The peak is the CO vibration peak. A comparison of the infrared spectra of the product from the above examples with those of the industrial-grade pure product shows a very high degree of similarity, with all peaks remaining essentially consistent. This further verifies that the method and system of this invention can produce sodium ethyl xanthate with high yield and high purity.

[0159] The above embodiments further demonstrate that this invention provides a system and method for preparing sodium ethyl xanthate based on microchannel technology. This method overcomes the limitations of traditional preparation processes in terms of mass and heat transfer, reaction control, and product quality, significantly improving reaction efficiency, product purity, and production safety. The core of this system and method lies in the use of microchannel reaction technology. Utilizing its efficient mass and heat transfer performance and controllable microscale reaction environment, precise control of reaction conditions is achieved, thereby significantly reducing the occurrence of side reactions and the amount of byproducts generated, resulting in more stable and reliable product quality. Compared to traditional batch reactors or kneading machines, the modular design of the microchannel reactor decomposes the reaction process into efficient and controllable continuous operations. This not only improves reaction efficiency but also reduces energy consumption and environmental pollution during production. Simultaneously, the system of this invention, combined with the synergistic effect of metering pumps, mixing pumps, concentration kettles, centrifuges, and dryers, solves the problems of uneven raw material delivery, difficulty in controlling reaction conditions, and low concentration and separation efficiency in traditional processes, achieving integrated and efficient production of sodium ethyl xanthate from reaction to product.

[0160] In terms of technical advantages, the present invention has the following significant advantages:

[0161] Highly efficient mass and heat transfer: The microscale channel design of the microchannel reactor significantly improves the mass and heat transfer efficiency of the reactants, ensuring uniform and thorough reaction and reducing the generation of by-products caused by local overheating or incomplete reaction.

[0162] Precise reaction control: By strictly controlling the reaction temperature, pressure and residence time of the microchannel reactor, reaction conditions can be optimized to improve product yield and purity.

[0163] High safety: The design of the microchannel reactor is inherently safe, effectively reducing the risk of flammability and explosion during xanthate synthesis and significantly improving the safety of production operations.

[0164] Environmentally friendly: Unreacted raw materials and byproducts are recycled through a condenser, reducing waste of raw materials and emissions.

[0165] Excellent product performance: Verification through examples shows that the sodium ethyl xanthate product produced by this invention has high yield and high purity, which can meet the stringent requirements of industrial applications.

[0166] In summary, this invention is not only innovative in reaction technology and system integration, but also effectively solves the problems of low reaction efficiency, high pollution, and high operational risks in existing technologies. It provides a safe, efficient, and environmentally friendly solution for the industrial preparation of sodium ethyl xanthate, with significant economic value and broad application prospects.

[0167] In the description of the embodiments of this application, it should be noted that the terms "inner" and "outer" and other terms indicating direction or positional relationship are based on the direction or positional relationship shown in the drawings. This is only for the convenience of description and does not indicate or imply that the device or component must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this application.

[0168] In the description of this application, the references to terms such as "an embodiment," "some embodiments," "in this embodiment," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0169] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for preparing sodium ethyl xanthate based on microchannel technology, characterized in that, The method relies on a system for preparing sodium ethyl xanthate based on microchannel technology. This system comprises the following components: a first storage tank (1), a second storage tank (2), and a third storage tank (3): used to store the reaction raw materials carbon disulfide, ethanol, and liquid alkali, respectively; a mixing pump (7): the input end of the mixing pump (7) is connected to the output ends of the first storage tank (1), the second storage tank (2), and the third storage tank (3), used to mix carbon disulfide, ethanol, and liquid alkali; and a microchannel reactor (8): the input end of the microchannel reactor (8) is connected to the output end of the mixing pump (7), used to receive the mixed reaction raw materials and react them at a set temperature and residence time to produce sodium ethyl xanthate. Sodium ethyl xanthate solution; Concentrator (9): The input end of the concentrator (9) is connected to the output end of the microchannel reactor (8) for vacuum distillation concentration of the sodium ethyl xanthate solution generated by the reaction in the microchannel reactor (8). The concentrator (9) is provided with a recovery output end and a product output end; Condenser (10): The input end of the condenser (10) is connected to the recovery output end (14) of the concentrator (9) for recovering unreacted raw materials and by-products; Centrifuge (11): The input end of the centrifuge (11) is connected to the product output end (15) of the concentrator (9) for separating the concentrated sodium ethyl xanthate; Dryer (12): The input end of the dryer (12) is connected to the output end of the centrifuge (11) for drying the separated sodium ethyl xanthate to obtain the final product; the output ends of the first storage tank (1), the second storage tank (2), and the third storage tank (3) are respectively connected to the first metering pump (4), the second metering pump (5), and the third metering pump (6), and the output ends of the first metering pump (4), the second metering pump (5), and the third metering pump (6) are connected to the input end of the mixing pump (7); the output end of the condenser (10) is connected to a receiving tank (13); the method includes the following steps: S1: Raw material preparation and transportation: Carbon disulfide, ethanol and liquid alkali are stored in the first storage tank (1), the second storage tank (2) and the third storage tank (3) respectively, and transported to the mixing pump (7) according to the preset molar equivalent ratio, and are initially mixed in the mixing pump (7); wherein, the liquid alkali is sodium hydroxide, and the concentration of the sodium hydroxide is 30-50%; the molar equivalent ratio of carbon disulfide, ethanol and liquid alkali is 1:1.05:1.05; S2: Microchannel reaction: The raw materials mixed in step S1 are sent into the microchannel reactor (8), and the reaction temperature and reaction residence time in the microchannel reactor (8) are controlled so that carbon disulfide, ethanol and liquid alkali react in the microchannel to generate sodium ethyl xanthate solution; wherein, the reaction temperature is 25-30℃ and the reaction residence time is 220 min. n; S3: Concentration treatment: The sodium ethyl xanthate solution generated in step S2 is output from the microchannel reactor (8) to the concentration vessel (9) and concentrated by distillation under reduced pressure. Unreacted raw materials and by-products are discharged from the recovery output end (14) of the concentration vessel (9) and recovered by the condenser (10). At the same time, the concentrated sodium ethyl xanthate solution is discharged from the product output end (15) of the concentration vessel (9); S4: Centrifugation separation: The sodium ethyl xanthate solution concentrated in step S3 is sent to the centrifuge (11) and the sodium ethyl xanthate solid and by-product liquid are separated by the centrifuge (11); S5: Drying treatment: The sodium ethyl xanthate solid separated by the centrifuge in step S4 is sent to the dryer (12) and the drying conditions are controlled to dry the product to obtain the final sodium ethyl xanthate product.

2. The method for preparing sodium ethyl xanthate based on microchannel technology according to claim 1, characterized in that, In step S2, the hydraulic diameter inside the microchannel reactor is 100-6000 micrometers.

3. The method for preparing sodium ethyl xanthate based on microchannel technology according to claim 1, characterized in that, In step S2, the reaction formula of the microchannel reaction is: C2H5OH+NaOH+CS2→C2H5OHCSSNa+H2O.

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