Process for the preparation of dimethyl telluride
By using dimethyl ether, boron triiodide, and disodium telluride as raw materials, combined with a simple distillation purification step, the complexity and environmental pollution problems in the preparation of dimethyl telluride have been solved, achieving efficient and low-cost preparation of high-purity dimethyl telluride, which is suitable for industrial production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ANHUI ARGOSUN NEW ELECTRONIC MATERIALS CO LTD
- Filing Date
- 2026-02-12
- Publication Date
- 2026-06-02
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Figure SMS_1
Abstract
Description
Technical Field
[0001] This invention relates to a method for synthesizing an organic tellurium compound, and more particularly to a method for preparing dimethyl tellurium. Background Technology
[0002] Dimethyl tellurium is an important organometallic compound. As a key organotellurium compound, dimethyl tellurium (CH3TeCH3) is widely used in the synthesis of tellurium-containing nV group compounds (such as CdTe and HgCdTe) to prepare thin-film solar cells, infrared detectors and optoelectronic devices.
[0003] Traditional methods for preparing dimethyl tellurium typically employ hydrazine hydrate benzaldehyde condensation, dimethyl phosphite, or dimethyl carbonate hydrazine hydrate methods. These methods generally suffer from drawbacks such as complex reaction steps, high energy consumption, and significant environmental pollution, hindering industrial production. Furthermore, traditional methylating agents, such as dimethyl sulfate, are only partially utilized, with the remaining atoms becoming waste, resulting in low resource utilization and the presence of highly toxic residues. This increases the difficulty of product purification and the risk of waste disposal, while also generating large amounts of inorganic salt byproducts that are difficult to separate and purify, leading to high post-processing costs and affecting product purity and yield. Other methods for preparing dimethyl tellurium include the Grignard reagent method and the methyllithium method. The Grignard reagent method involves preparing a Grignard reagent from halomethane and magnesium, which then reacts with telluride to generate dimethyl tellurium. However, this method requires strictly anhydrous and oxygen-free conditions, and the Grignard reagent has poor stability, easily causing safety accidents. Additionally, the reaction process readily generates large amounts of byproducts, resulting in low product purity and increased difficulty in subsequent separation. While the lithium methylmethoxide method exhibits high reactivity, its production is expensive, and the reaction is vigorous and difficult to control, making it unsuitable for large-scale industrial production. Therefore, developing a safe, efficient, and low-cost method for preparing dimethyl tellurium has become an urgent technical challenge. Summary of the Invention
[0004] Purpose of the invention: The purpose of this invention is to provide a method for preparing dimethyl tellurium, thereby solving the problem of how to efficiently prepare pure dimethyl tellurium.
[0005] Technical solution: The present invention provides a method for preparing dimethyl tellurium, comprising the following steps: Dimethyl ether solution was slowly added to boron triiodide solution for reaction. The organic phase of the reaction mixture was washed, separated, and dried, and then added to disodium telluride methanol solution for reaction. The reaction product was purified to obtain dimethyl telluride.
[0006] Preferably, the dimethyl ether solution is prepared by: At low temperature, dimethyl ether gas is passed into an aqueous methanol solution, and the solution is naturally heated to room temperature to obtain a dimethyl ether solution.
[0007] Furthermore, the low temperature is -50 to -20°C, and the molar ratio of dimethyl ether, methanol, and water is 1:5-10:5-10.
[0008] Preferably, the boron triiodide solution is a methanol solution of boron triiodide.
[0009] Preferably, the molar ratio of dimethyl ether, boron triiodide and disodium telluride is 6-8:4:2-3.
[0010] Preferably, the reaction conditions for the dimethyl ether solution and the boron triiodide solution are: stirring at 10-30°C for 1-12 hours; The washing method is as follows: water is added to the reaction mixture, and after mixing, the organic phase is separated. The drying method is as follows: add the organic phase into a filter containing a desiccant, stir, filter, and collect the filtrate.
[0011] In some embodiments, the desiccant may be selected from at least one of anhydrous sodium sulfate and anhydrous magnesium sulfate.
[0012] Furthermore, the volume ratio of water added to the reaction mixture to the organic solvent in the dimethyl ether solution is 1-2:1; the washing is performed at least twice.
[0013] Preferably, the reaction conditions for the organic phase and the disodium telluride methanol solution are: stirring at 20-50°C for 3-9 hours under an inert atmosphere; In some embodiments, the inert atmosphere is an inert gas atmosphere such as nitrogen, argon, or helium, in which the water and oxygen content is ≤1 ppm.
[0014] Preferably, the purification method is as follows: The reaction product was distilled at 70-75℃ to remove light components until no more distillate was distilled off. The temperature was then raised to 82-85℃ and distillation was continued. The fraction distilled at 80-84℃ was collected to obtain crude dimethyl tellurium. The crude dimethyl tellurium product was refluxed at 84-88℃ for 1-3 hours under normal pressure to remove the front and rear fractions. The middle fraction was collected to obtain the purified dimethyl tellurium product.
[0015] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) The present invention uses low-toxicity and inexpensive dimethyl ether to replace highly toxic dimethyl sulfate or expensive iodomethane, which fundamentally solves the raw material safety bottleneck and significantly reduces production costs.
[0016] (2) The synthetic route of the present invention using dimethyl ether, boron triiodide and disodium telluride as the main raw materials can significantly reduce the by-products and impurities in the direct product, simplify the subsequent purification steps, and obtain high-purity dimethyl telluride by simple distillation, which effectively improves the yield and purity of the final product and has good prospects for industrial application.
[0017] (3) The present invention does not require strict reaction conditions, the reaction process is simple and controllable, and the safety is good. Detailed Implementation
[0018] The technical solution of the present invention will be further described below.
[0019] Example 1: A method for preparing dimethyl tellurium is as follows: (1) Pour 320g of methanol and 180g of water into a 1L four-necked flask and start stirring. Maintain the temperature of the four-necked flask at -35℃. Connect the condenser to the top and control the temperature at -35℃. After introducing 92g of dimethyl ether gas into it, stop freezing the bottom flask and let it rise to room temperature naturally to obtain the standby liquid. (2) Add 522g of boron triiodide and 1L of methanol to a 3L reaction flask, turn on the stirrer, and slowly add the prepared solution to the reaction flask through a constant pressure dropping funnel. During the dropping process, maintain the reaction temperature at 20℃. After the dropping is completed, keep the stirring stirring for 3h. (3) After the reaction is complete, add 400 mL of water to a separatory funnel and mix evenly to obtain the organic phase. Repeat the water washing operation twice. Add the washed organic phase to a filter containing anhydrous sodium sulfate as a desiccant and stir to obtain the filtrate. Add all the filtrate dropwise through a constant pressure dropping funnel to a 3 L reaction flask containing 173.6 g of disodium telluride and 1 L of methanol. After the dropwise addition is complete, slowly raise the temperature to 35 °C and continue stirring for 6 h. (4) After the reaction is complete, the temperature of the bottom flask is controlled at 75°C to remove the light components by distillation until no distillate is obtained. Then the temperature is raised to 82~85°C to continue distillation. The fraction at 80-84°C is collected to obtain crude dimethyl tellurium. (5) The crude dimethyl tellurium product is subjected to atmospheric distillation. The bottom temperature is controlled at 84~88℃ and refluxed for 2 hours. The front and rear fractions are removed at a ratio of 10% of the feed amount. The middle fraction is the high-purity dimethyl tellurium product.
[0020] The obtained dimethyltellurium product was analyzed by a JNM-ECZ400S nuclear magnetic resonance spectrometer, and the results were as follows: 1 H NMR (400MHz, C6D6) δ: 1.83 (s, 6H). Example 2: Everything else is the same as in Example 1, except that: In step (1), 512g of methanol and 288g of water were poured into a 2L four-necked flask and stirred. The temperature of the four-necked flask was maintained at -40℃, and the temperature of the condenser connected to it was controlled at -40℃. 92g of dimethyl ether gas was introduced into it, and the bottom flask was stopped from freezing and naturally rose to room temperature to obtain the standby liquid. In step (2), the reaction temperature is maintained at 10°C during the dropwise addition process, and the reaction is stirred for 12 hours after the dropwise addition is completed.
[0021] In step (4), the temperature of the bottom flask is controlled at 70°C to distill away the light components until no more distillate is produced.
[0022] Example 3: Everything else is the same as in Example 1, except that: In step (1), 640g of methanol and 360g of water were poured into a 2L four-necked flask and stirred. The temperature of the four-necked flask was maintained at -30℃, and the temperature of the condenser connected to it was controlled at -30℃. 92g of dimethyl ether gas was introduced into it, and the bottom flask was stopped from freezing and naturally rose to room temperature to obtain the standby liquid. In step (3), after the reaction is complete, 500 mL of water is added to a separatory funnel and mixed evenly to obtain the organic phase.
[0023] Example 4: Everything else is the same as in Example 1, except that: In step (1), 512g of methanol and 288g of water were poured into a 2L four-necked flask and stirred. The temperature of the four-necked flask was maintained at -50℃, and the temperature of the condenser connected to it was controlled at -50℃. 92g of dimethyl ether gas was introduced into it, and the bottom flask was stopped from freezing and naturally rose to room temperature to obtain the standby liquid. In step (2), add 391.5g of boron triiodide and 1L of methanol to a 3L reaction flask and start stirring.
[0024] In step (3), all the filtrate is added dropwise through a constant pressure dropping funnel to a 3L reaction flask containing 86.8g of disodium telluride and 1L of methanol.
[0025] Example 5: Everything else is the same as in Example 1, except that: In step (1), 512g of methanol and 288g of water were poured into a 2L four-necked flask and stirred. The temperature of the four-necked flask was maintained at -20℃, and the temperature of the condenser connected to it was controlled at -20℃. 92g of dimethyl ether gas was introduced into it, and the bottom flask was stopped from freezing and naturally rose to room temperature to obtain the standby liquid. In step (2), add 391.5g of boron triiodide and 1L of methanol to a 3L reaction flask and start stirring.
[0026] In step (3), all the filtrate is added dropwise through a constant pressure dropping funnel to a 3L reaction flask containing 130.2g of disodium telluride and 1L of methanol.
[0027] The dimethyl tellurium products obtained in Examples 2-5 were analyzed by a JNM-ECZ400S nuclear magnetic resonance spectrometer, and the results were all as follows: 1 H NMR (400MHz, C6D6) δ: 1.83 (s, 6H). Comparative Example 1: Dimethyl tellurium was prepared using dimethyl sulfate, as follows: (1) Under an anhydrous and oxygen-free environment, add 50.3 g of disodium telluride and 375 mL of N,N-dimethylformamide as a solvent to the reaction flask, start stirring to form a gray suspension, and then cool the reaction system to -10℃~-5℃. Weigh 63 g of dimethyl sulfate and place it in a constant pressure dropping funnel, and slowly add dimethyl sulfate to the gray suspension of disodium telluride. After the addition is complete, continue to stir the reaction at a low temperature for 2 hours to allow the reaction to proceed fully. (2) After the reaction is complete, remove the freezer and allow the reaction mixture to slowly heat up to room temperature (20-30°C) under stirring, and continue stirring for 1 hour; (3) Change the reaction apparatus to an atmospheric pressure distillation apparatus, keep the whole system under inert gas protection, raise the temperature to 82~85℃ for distillation, and collect the fraction at 80-84℃ to obtain crude dimethyl tellurium. The obtained crude dimethyl tellurium was subjected to atmospheric distillation, and the bottom temperature was controlled at 84~88℃ and refluxed for 2 hours. The front and rear fractions were removed at a ratio of 10% of the feed amount, and the middle fraction was collected to obtain the finished dimethyl tellurium product.
[0028] Comparative Example 2: Dimethyltellurium was prepared using the Grignard reagent method, as follows: (1) Under an inert atmosphere, 50 g of magnesium shavings and 1.2 L of diethyl ether solvent were added to a 2 L four-necked flask. Stirring was started, and then 213 g of iodomethane was slowly added dropwise. After the addition was completed, stirring was continued for 1 h to obtain a magnesium methyl iodide solution. (2) Add 67g of tellurium tetrachloride to 200mL of diethyl ether and stir to form a tellurium tetrachloride suspension; (3) Cool the Grignard reagent methyl magnesium iodide to 0~10℃, then slowly add tellurium tetrachloride ether solution. After the addition is complete, let it rise to room temperature naturally and stir for 12h. (4) The reaction product is slowly heated to 75°C and distilled to remove the ether until no distillate is obtained. Then the temperature is raised to 82-85°C and distillation is continued. The fraction at 80-84°C is collected to obtain crude dimethyl tellurium. The obtained crude dimethyl tellurium was subjected to atmospheric distillation, and the bottom temperature was controlled at 84~88℃ and refluxed for 2 hours. The front and rear fractions were removed at a ratio of 10% of the feed amount, and the middle fraction was collected to obtain the finished dimethyl tellurium product.
[0029] Comparative Example 3: Dimethyl tellurium was prepared using the lithium methylmethionine method, as follows: (1) Add 27g of tellurium tetrachloride to a 1L reaction flask, and then add 200 mL of diethyl ether solvent and stir to obtain a diethyl ether solution of tellurium tetrachloride; (2) Cool the tellurium tetrachloride ether solution to 0~10℃, and slowly add the lithium methyl ether solution (1.6 M, 250 mL) to the ether solution of TeCl4 using a constant pressure dropping funnel. After the addition is complete, let it rise naturally to room temperature and continue stirring for 12 hours. (3) The reaction product is slowly heated to 75°C and distilled to remove the ether until no distillate is obtained. Then the temperature is raised to 82-85°C and distillation is continued. The fraction at 80-84°C is collected to obtain crude dimethyl tellurium. (4) The crude dimethyl tellurium product is subjected to atmospheric distillation. The bottom temperature is controlled at 84~88℃ and refluxed for 2 hours. The front and rear fractions are removed at a ratio of 10% of the feed amount. The middle fraction is collected to obtain the dimethyl tellurium product.
[0030] The dimethyl tellurium products obtained in Examples 1-5 and Comparative Examples 1-3 were subjected to NMR and ICP analysis, and all inorganic elements were detected using an inductively coupled plasma atomic emission spectrometer (Optima 8000). The results are as follows: Table 1. Yield and purity of dimethyl tellurium prepared by different methods
[0031] As shown in Table 1, the yields of crude dimethyl tellurium in Examples 1-5 were significantly higher than those in Comparative Examples 1-3. This indicates that most atoms in the raw materials of the present invention are converted into the target product, and the amount of by-products generated is significantly lower than that of existing synthesis methods, resulting in higher raw material utilization. Meanwhile, the purity and impurity content of the dimethyl tellurium products obtained in Examples 1-5 were significantly lower than those in Comparative Examples 1-3. This is mainly because existing methods generate a large number of by-products, making it difficult to separate and purify dimethyl tellurium using conventional distillation methods, thus hindering the acquisition of high-purity dimethyl tellurium final products. In contrast, the present invention generates fewer by-products and impurities, significantly reducing the difficulty of subsequent separation and purification. A dimethyl tellurium product with a purity of 6N can be obtained using a simple distillation method, significantly reducing post-processing costs.
Claims
1. A method for preparing dimethyl tellurium, characterized in that, Includes the following steps: Dimethyl ether solution was slowly added to boron triiodide solution for reaction. The organic phase of the reaction mixture was washed, separated, and dried, and then added to disodium telluride methanol solution for reaction. The reaction product was purified to obtain dimethyl telluride.
2. The method for preparing dimethyltellurium according to claim 1, characterized in that, The dimethyl ether solution is prepared as follows: At low temperature, dimethyl ether gas is passed into an aqueous methanol solution, and the solution is naturally heated to room temperature to obtain a dimethyl ether solution.
3. The method for preparing dimethyltellurium according to claim 2, characterized in that, The low temperature is -50 to -20°C, and the molar ratio of dimethyl ether, methanol and water is 1:5-10:5-10.
4. The method for preparing dimethyltellurium according to claim 1, characterized in that, The boron triiodide solution is a methanol solution of boron triiodide.
5. The method for preparing dimethyltellurium according to claim 1, characterized in that, The molar ratio of dimethyl ether, boron triiodide, and disodium telluride is 6-8:4:2-3.
6. The method for preparing dimethyltellurium according to claim 1, characterized in that, The reaction conditions for the dimethyl ether solution and the boron triiodide solution are: stirring at 10-30℃ for 1-12 hours; The washing method is as follows: water is added to the reaction mixture, and after mixing, the organic phase is separated. The drying method is as follows: add the organic phase into a filter containing a desiccant, stir, filter, and collect the filtrate.
7. The method for preparing dimethyltellurium according to claim 6, characterized in that, The volume ratio of water added to the reaction mixture to the organic solvent in the dimethyl ether solution is 1-2:1; the washing is performed at least twice.
8. The method for preparing dimethyltellurium according to claim 1, characterized in that, The reaction conditions for the organic phase and the disodium telluride methanol solution are: stirring at 20-50℃ for 3-9 hours under an inert atmosphere.
9. The method for preparing dimethyltellurium according to claim 1, characterized in that, The purification method is as follows: The reaction product was distilled at 70-75℃ to remove light components until no more distillate was distilled off. The temperature was then raised to 82-85℃ and distillation was continued. The fraction distilled at 80-84℃ was collected to obtain crude dimethyl tellurium. The crude dimethyl tellurium product was refluxed at 84-88℃ for 1-3 hours under normal pressure to remove the front and rear fractions. The middle fraction was collected to obtain the purified dimethyl tellurium product.