High-efficiency ethylene preparation method

Abstract

The invention provides a high-efficiency ethylene preparation method, and relates to the technical field of chemical synthesis. According to the method, ethephon ClCH2CH2PO (OH) 2 is used as an ethylene precursor, barium hydroxide Ba (OH) 2 is used as an alkaline reaction medium, ethylene is efficiently prepared through hydrolysis reaction at normal temperature, and high temperature and strong acid are not needed in the core reaction. The core innovation lies in that a'mild hydrolysis-directional gas production 'technology is adopted, the raw material ratio and reaction conditions are optimized, rapid gas production within 1 minute is realized, and the purity of ethylene is greater than or equal to 92%; the raw materials are easy to purchase, low in price and high in safety, byproducts can be recycled, and the problems that a traditional concentrated sulfuric acid dehydration method is high in corrosion risk, large in energy consumption and many in byproducts are solved. The method is easy and convenient to operate and visual in phenomenon, the gas production efficiency is improved by 60% or above compared with that of a traditional method, the cost is reduced by 50%, the ethylene property verification requirement in teaching is met, efficient preparation of small experiment scenes is also adapted, and remarkable safety, economical efficiency and practicability are achieved.

Description

Technical Field

[0001] This invention relates to the field of chemical synthesis technology, specifically to a high-efficiency method for preparing ethylene. Background Technology

[0002] Ethylene, as an important basic raw material in organic chemical engineering, is also a core substance for verifying the properties of unsaturated hydrocarbons in chemistry teaching. Traditional laboratory methods for preparing ethylene mainly rely on the "ethanol-concentrated sulfuric acid dehydration method," which has several insurmountable drawbacks: High safety risks: 98% concentrated sulfuric acid is required as a catalyst and dehydrating agent. Its strong corrosiveness can easily cause equipment corrosion and personnel burns. In addition, the reaction needs to be heated to 170°C. Ethanol is easy to carbonize at high temperatures, which poses the risk of violent boiling and material overflow. Energy consumption and by-product issues: The high temperature of 170℃ requires continuous heating, which consumes a lot of energy and is prone to side reactions (such as the generation of diethyl ether at 140℃), resulting in low ethylene purity, usually ≤80%, and by-products polluting the environment. Operational and cost limitations: The raw materials require high-purity ethanol and concentrated sulfuric acid, which require strict storage conditions and are expensive. In addition, the operation process is complicated and the reaction time is long, which is not conducive to rapid observation in teaching demonstrations. Poor teaching applicability: The reaction phenomena are not intuitive, the black substances produced by carbonization can easily interfere with students' understanding of the principle of ethylene preparation, and the corrosive reagents limit the conduct of group experiments for students.

[0003] Although existing improvement methods attempt to replace catalysts, they still rely on high temperatures and highly corrosive reagents, or suffer from problems such as difficulty in procuring raw materials and low gas production efficiency.

[0004] Therefore, developing a safe, rapid, and low-cost method for preparing ethylene at room temperature is crucial to meeting the needs of teaching and small-scale experimental scenarios. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a high-efficiency ethylene production method, which solves the problems that existing improved methods, although attempting to replace catalysts, still rely on high temperatures and highly corrosive reagents, or suffer from difficulties in procuring raw materials and low gas production efficiency.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A high-efficiency method for preparing ethylene uses ethephon ClCH2CH2PO(OH)2 as an ethylene precursor and an alkaline compound as a reaction medium to prepare ethylene through a hydrolysis reaction at room temperature. The preparation method includes the following steps: Step 1: Raw material preparation Take ethephon and an alkaline compound in a molar ratio of 1:2 to 1:4, wherein the ethephon is an aqueous solution with a mass fraction of 30% to 50%, and the alkaline compound is solid barium hydroxide. Step 2: Reaction Initiation Add the alkaline compound to the reaction vessel, then slowly inject an aqueous solution of ethephon, gently shake to mix the materials evenly, and start the hydrolysis reaction at room temperature and pressure; Step 3: Gas Collection The generated ethylene gas is collected using the water displacement gas collection method, with a collection time of ≤5 minutes. Step 4: Target Product Validation The collected ethylene gas is passed into bromine water or acidic potassium permanganate solution, and the ethylene is verified by the decolorization of the solution. If it is qualified, it can be used for subsequent experiments or applications.

[0007] Furthermore, the chemical equation for the reaction in the preparation method is as follows: When the alkaline compound is barium hydroxide, the chemical equation is: 6ClCH2CH2PO (OH)2 + 12Ba (OH)2 =3BaCl2 + 6CH2=CH2↑+ 3Ba3(PO4)2 ↓+ 18H2O. Furthermore, the byproducts generated by the reaction are barium chloride (BaCl2) and barium phosphate (Ba3(PO4)2). After filtration and drying, the byproducts can be recycled for use in other chemical experiments.

[0008] Furthermore, when the alkaline compound is solid barium hydroxide, the reaction does not require the addition of additional water.

[0009] Furthermore, in step one, the preferred molar ratio of ethephon to the alkaline compound is 1:2. When barium hydroxide solid is used, the amount of 40% mass fraction ethylene used is 10g, and the amount of barium hydroxide solid used is 9.5g.

[0010] Furthermore, in step two, the reaction vessel is a test tube with a delivery tube or a test tube with a branch. When injecting the ethephon aqueous solution, it is slowly added along the container wall to avoid violent splashing. The oscillation frequency is 5 to 10 times / minute, and the mixing time is ≤30 seconds.

[0011] Furthermore, in the water displacement gas collection method of step three, the end of the conduit of the reaction vessel is inserted underwater, the collection device is kept sealed, the purity of ethylene gas is ≥92%, and the gas production volume in a single reaction cycle is 50-150 mL.

[0012] Furthermore, the preparation method is suitable for chemical teaching demonstrations, ethylene property verification experiments, or temporary preparation scenarios in small laboratories. The chemical properties of ethylene can be directly verified through bromine water addition reaction and acidic potassium permanganate oxidation reaction.

[0013] This invention provides a high-efficiency method for preparing ethylene. It has the following beneficial effects: 1. This invention provides a high-efficiency method for preparing ethylene, breaking through the traditional high-temperature strong acid system. It adopts a hydrolysis reaction at room temperature and pressure, using ethephon and alkaline compounds as raw materials. It is free from corrosion and high-temperature risks, significantly improving safety. It supports barium hydroxide solid alkaline media, is suitable for different experimental scenarios, and the solid reaction is easy to operate, while the liquid reaction produces gas uniformly, making it more flexible.

[0014] 2. This invention provides a high-efficiency ethylene preparation method. By precisely controlling the molar ratio of raw materials to 1:2, rapid gas production can be achieved within 1 minute. The gas production efficiency is increased by 60% compared with traditional methods. The ethylene purity is ≥92%, and the by-products are non-toxic solid salts that can be recycled for other experiments. There is no environmental pollution, which is in line with the concept of green chemistry.

[0015] 3. This invention provides a highly efficient method for preparing ethylene, with more intuitive reaction phenomena, continuous bubble generation, rapid decolorization of the solution for property verification, simplified operation steps, and suitability for classroom demonstrations and student group experiments, effectively lowering the teaching threshold. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the experimental apparatus for ethylene preparation according to the present invention; Figure 2 This is a schematic diagram illustrating the ethylene preparation reaction principle of the present invention; Figure 3 This is a performance comparison diagram between the preparation method of the present invention and the conventional method. Detailed Implementation

[0017] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0018] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0019] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0020] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0021] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0022] like Figures 1-3 As shown, this embodiment of the invention provides a high-efficiency ethylene preparation method based on the hydrolysis reaction of ethephon under strongly alkaline conditions. Ethephon ClCH2CH2PO(OH)2 is a commonly used plant growth regulator in agriculture. The phosphate ester group contained in the molecular structure of ethephon is easily hydrolyzed in an alkaline environment, releasing ethylene gas CH2=CH2 in a directional manner. The reaction is mild and has no side reaction interference. The chemical equation for the reaction in this preparation method is: The reaction equation for the barium hydroxide system is: 6ClCH2CH2PO (OH)2 + 12Ba (OH)2 → 3BaCl2 + 6CH2=CH2↑ + 3Ba3(PO4)2 ↓ + 18H2O; The reaction mechanism is as follows: the alkaline medium provides OH⁻, which attacks the phosphate ester bond in the ethephon molecule, causing the CP bond to break. At the same time, the β-elimination reaction generates ethylene, and the byproducts are stable salts and water, with no harmful gases produced.

[0023] The specific steps of this preparation method are as follows: Step 1: Raw material preparation Ethephon selection: Use an aqueous solution with a mass fraction of 30% to 50% (commercially available agricultural grade ethephon can be directly diluted for use), with a purity of ≥95%, and no additional purification is required; Selection of basic compounds: Barium hydroxide system: Take 9.5g of analytical grade barium hydroxide solid, ensuring no lumps, and store it in a dry place; Raw material ratio: Weigh strictly according to the molar ratio of 1:2 to ensure complete reaction and avoid waste of raw materials or side reactions.

[0024] Step 2: Reaction Initiation Container preparation: Select a 25mL test tube with a single-hole stopper and delivery tube. Check the seal. Connect one end of the delivery tube to the test tube and leave the other end for gas collection. Material mixing: First, add 9.5g of Ba(OH)2 solid to the test tube, then slowly pour in 10g of 40% ethephon aqueous solution, pouring along the test tube wall to avoid splashing.

[0025] Step 3: Gas Collection Gas production observation: Uniform bubbles begin to be produced within 10 to 30 seconds at room temperature, and the gas production time is 3 to 5 minutes. Collection procedure: Fill the gas collecting bottle with water and invert it in the water tank. Insert the end of the tube into the water. After the bubbles are generated stably, collect the ethylene gas. The collection volume should be controlled between 50 and 150 mL as needed. Gas storage: After collection, place the gas collecting bottle upright and seal it with a glass plate to prevent ethylene leakage.

[0026] Step 4: Validation and Application of Target Product Addition reaction verification: The collected ethylene was passed into 0.1 mol / L bromine water, and the bromine water was observed to decolorize rapidly within 10 to 20 seconds, proving that the purity of ethylene was qualified; Oxidation reaction verification: When 0.01 mol / L acidic potassium permanganate solution was passed through, the purple-red color of the solution faded, further confirming the unsaturation of ethylene.

[0027] Subsequent applications: Qualified ethylene gas can be used for property verification experiments in teaching, or for research on addition reactions, polymerization reactions, etc. in small laboratories.

[0028] Example 2: Barium hydroxide system Raw material preparation: 10g of 40% ethephon (0.0278mol), 9.5g of barium hydroxide solid (0.056mol), with a molar ratio of 1:2.01, close to 1:2, to ensure excess alkalinity; Procedure: Add barium hydroxide solid to a 25mL test tube, inject ethephon aqueous solution, shake 5 times, and after 30 seconds, uniform bubbles will begin to be generated. Collect 100mL of ethylene gas by water displacement method for 4 minutes. Purity verification: When ethylene was passed into 0.1 mol / L bromine water, the bromine water completely decolorized within 20 seconds; when passed into acidic potassium permanganate solution, the purple-red color disappeared within 15 seconds. The purity of ethylene was tested to be 94%. Implementation results: The reaction phenomenon is intuitive, bubbles are continuously generated, the property verification reaction is rapid, and students can clearly observe the whole process in the classroom demonstration, resulting in significant teaching effects.

[0029] The method requires minimal raw materials, is simple to operate, poses no safety risks, and produces a moderate gas flow rate, facilitating hands-on demonstrations and verifications of the properties of ethylene gas. Up to 30 groups of students can conduct experiments simultaneously, and byproducts are recycled for use in electrolyte conductivity experiments, achieving resource recycling.

[0030] Example 3: Comparative Experiment with Traditional Methods Traditional method: Ethanol + concentrated sulfuric acid system, heated to 170℃, reacted for 30 minutes, ethylene was collected with a purity of 80%, raw material cost was about 0.8 yuan / time; The method of this invention: Barium hydroxide + ethephon system, react at room temperature for 4 minutes, collect ethylene with a purity of 94%, and the raw material cost is about 0.4 yuan / time; Comparative results: The method of the present invention reduces the reaction time by 87%, increases the purity by 17.5%, reduces the cost by 50%, and its safety and ease of operation far exceed those of traditional methods.

[0031] The following points should be noted in this article: 1. The accompanying drawings of the embodiments disclosed herein only relate to the structures involved in the embodiments disclosed herein; other structures can be referred to in a general design.

[0032] 2. Where there is no conflict, the embodiments of this disclosure and the features in the embodiments can be combined with each other to obtain new embodiments.

[0033] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A high-efficiency method for preparing ethylene, characterized in that, Ethylene was prepared by hydrolysis at room temperature using ethephon ClCH2CH2PO(OH)2 as an ethylene precursor and an alkaline compound as a reaction medium. The preparation method includes the following steps: Step 1: Raw material preparation Take ethephon and an alkaline compound in a molar ratio of 1:2 to 1:4, wherein the ethephon is an aqueous solution with a mass fraction of 30% to 50%, and the alkaline compound is solid barium hydroxide. Step 2: Reaction Initiation Add the alkaline compound to the reaction vessel, then slowly inject an aqueous solution of ethephon, gently shake to mix the materials evenly, and start the hydrolysis reaction at room temperature and pressure; Step 3: Gas Collection The generated ethylene gas is collected using the water displacement gas collection method, with a collection time of ≤5 minutes. Step 4: Target Product Validation The collected ethylene gas is passed into bromine water or acidic potassium permanganate solution, and the ethylene is verified by the decolorization of the solution. If it is qualified, it can be used for subsequent experiments or applications.

2. The high-efficiency ethylene preparation method according to claim 1, characterized in that, The chemical equation for the reaction in the preparation method is as follows: When the alkaline compound is barium hydroxide, the chemical equation is: 6ClCH2CH2PO (OH)2 + 12Ba (OH)2 = 3BaCl2 + 6CH2=CH2↑+ 3Ba3(PO4)2 ↓+ 18H2O.

3. The high-efficiency ethylene preparation method according to claim 3, characterized in that, The byproducts generated by the reaction are barium chloride (BaCl2) and barium phosphate (Ba3(PO4)2). After filtration and drying, the byproducts can be recycled for use in other chemical experiments.

4. The high-efficiency ethylene preparation method according to claim 1, characterized in that, When the alkaline compound is solid barium hydroxide, the reaction does not require the addition of additional water.

5. The high-efficiency ethylene preparation method according to claim 1, characterized in that, In step one, the preferred molar ratio of ethephon to the alkaline compound is 1:

2. When barium hydroxide solid is used, the amount of 40% mass fraction ethylene used is 10g, and the amount of barium hydroxide solid used is 9.5g.

6. The high-efficiency ethylene preparation method according to claim 1, characterized in that, In step two, the reaction vessel is a test tube with a delivery tube or a test tube with a branch. When injecting the ethephon aqueous solution, add it slowly along the container wall to avoid violent splashing. The oscillation frequency is 5 to 10 times / minute, and the mixing time is ≤30 seconds.

7. The high-efficiency ethylene preparation method according to claim 1, characterized in that, In the water displacement gas collection method of step three, the end of the conduit of the reaction vessel is inserted underwater, the collection device is kept sealed, the purity of ethylene gas is ≥92%, and the gas production volume in a single reaction cycle is 50-150 mL.

8. The high-efficiency ethylene preparation method according to claim 1, characterized in that, The preparation method described is suitable for chemical teaching demonstrations, ethylene property verification experiments, or temporary preparation scenarios in small laboratories. It can directly verify the chemical properties of ethylene, such as the addition reaction with bromine water and the oxidation reaction with acidic potassium permanganate.

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