CN-117263768-B - Preparation method of deuterated methyl iodide

CN117263768BCN 117263768 BCN117263768 BCN 117263768BCN-117263768-B

Abstract

The invention discloses a preparation method of deuterated methyl iodide, which comprises the following steps of adding an aprotic solvent into a reactor, sequentially adding an iodine simple substance and an iron powder catalyst under stirring at room temperature, replacing gas in the reactor with inert gas atmosphere, stirring, heating to rise temperature until condensation reflux occurs, adding deuterated methyl alcohol, reacting in a dark environment until the reaction is finished, cooling reaction liquid to room temperature, adding deionized water for extraction and liquid separation, filtering an organic phase to recover the iron powder catalyst, adding copper powder for stirring reaction to remove the iodine simple substance, adding anhydrous calcium chloride for drying, filtering, and collecting a target product deuterated methyl iodide through reduced pressure distillation. Compared with the prior art, the invention provides a method for preparing methyl iodide by catalyzing with a heterogeneous catalyst, which aims to solve the technical problems of high reactant toxicity, low reaction yield, difficult recovery of an acid catalyst and the like in the prior art.

Inventors

WANG JIANGUO
HUANG WEI
SHAO FANGJUN
WANG KUI
JIANG WENJIE

Assignees

浙江工业大学

Dates

Publication Date: 20260505
Application Date: 20230816

Claims (5)

1. The preparation method of the deuterated methyl iodide is characterized by comprising the following steps of: 1) Adding an aprotic solvent into a reactor, sequentially adding an iodine simple substance and an iron powder catalyst under stirring at room temperature, replacing gas in the reactor with an inert gas atmosphere, stirring, heating until condensation reflux occurs, adding deuterated methanol, and reacting in a dark environment until the reaction is finished; 2) Cooling the reaction liquid to room temperature, adding deionized water for extraction and liquid separation, filtering an organic phase to recover an iron powder catalyst, adding copper powder for stirring reaction to remove iodine simple substance, adding anhydrous calcium chloride for drying, filtering, and collecting a filtrate through reduced pressure distillation to obtain a target product deuterated methyl iodide; the aprotic solvent is selected from carbon tetrachloride; the mol ratio of the deuterated methyl alcohol to the iodine simple substance in the step 1) is 1:2-2.5, and the mol ratio of the iron powder to the iodine simple substance is 1.5-2:1 The reaction temperature is 90-92 ℃ and the reaction time is 10-20min.
2. The method of claim 1, wherein the volume of aprotic solvent used in step 1) is 5-20 times the volume of deuterated methanol.
3. The method of preparing deuterated iodomethane according to claim 2 wherein the aprotic solvent is present in an amount of 5 to 10 times the volume of deuterated methanol.
4. The method of claim 1, wherein the inert gas in step 1) is nitrogen or argon.
5. The process for preparing deuterated iodomethane according to claim 1 wherein the reduced pressure distillation in step 2) is carried out at a temperature of 35-60 ℃ for a distillation time of 10-20 minutes.

Description

Preparation method of deuterated methyl iodide Technical Field The invention relates to a preparation method of halogenated fine chemicals, in particular to a preparation method of deuterated methyl iodide. Background Deuterated methyl iodide is a monoiodo substituent of methane, has a molecular formula of CH 3 I or MeI, is colorless transparent liquid at normal temperature, has a boiling point of 40.3 ℃, has a density of 2.28g/cm 3, is soluble in water and is miscible with common organic solvents, is easy to decompose by visible light, and is usually added with copper powder to remove iodine simple substance generated by the decomposition of deuterated methyl iodide. Methyl iodide is commonly used as a methylating agent in organic synthesis and is commonly used in methylation reactions of alcohols, phenols, ketones, esters, carboxylic acids, amino compounds, cyano compounds, nitro compounds, alkanes, sulfones, sulfoxides, imines and hydrazones. Methyl iodide is also an initiator of the grignard reaction and is used for initiating the grignard reaction of the inert halogenated hydrocarbon. The conventional method for preparing methyl iodide in the prior art, such as the catalytic preparation of red phosphorus by taking methanol and iodine simple substances as raw materials, is more suitable for secondary alcohol or tertiary alcohol as substrates, so that the reaction of other alcohols as substrates is limited. Methanol and potassium iodide are used as reaction raw materials, methyl iodide is prepared under the condition of Lewis acid catalysis, the method has the advantages of convenient reagent source and simple operation, and hydriodic acid is generated through the reaction of iodized salt and Lewis acid, but the yield is lower and can only reach 40 percent at most. The pure methyl iodide is prepared from dimethyl sulfate and potassium iodide in the presence of calcium carbonate, and the pure methyl iodide can be obtained by simply distilling the product and washing the product with saturated Na 2S2O3 and Na 2CO3 solutions due to the large difference between the boiling points of the dimethyl sulfate and the methyl iodide. The method has high yield and easy separation of products, but the reactant dimethyl sulfate is extremely toxic and is carried out in a pressurized environment, thus being easy to cause harm to operators. Disclosure of Invention Aiming at the technical problems existing in the prior art, the invention aims to provide a method for preparing methyl iodide by catalyzing a heterogeneous catalyst, which aims to overcome the defects of high toxicity of reactants, low reaction yield and difficult recovery of an acid catalyst in the prior art, and provides a method for easily separating and recovering the catalyst, wherein the method has the advantages of economical and convenient reagent source, convenient operation and higher yield. The invention adopts the technical concept that deuterated methanol and iodine simple substance are used as raw materials to react under the catalysis of iron powder, and the products are collected from the reaction liquid. The technical scheme adopted by the invention is as follows: a method for preparing deuterated methyl iodide, comprising the following steps: 1) Adding an aprotic solvent into a reactor, sequentially adding an iodine simple substance and an iron powder catalyst under stirring at room temperature, replacing gas in the reactor with an inert gas atmosphere, stirring, heating until condensation reflux occurs, adding deuterated methanol, and reacting in a dark environment until the reaction is finished; 2) Cooling the reaction liquid to room temperature, adding deionized water for extraction, separating liquid, filtering an organic phase to recover an iron powder catalyst, adding copper powder, stirring for reaction to remove iodine simple substance, adding anhydrous calcium chloride for drying, filtering, and collecting a filtrate through reduced pressure distillation to obtain the target product deuterated methyl iodide. Further, the aprotic solvent in the step 1) is selected from one of dimethyl sulfoxide, carbon tetrachloride, paraxylene, 1,3, 5-trimethylbenzene, dioxane and 2-methylimidazolone, and the volume of the aprotic solvent is 5-20 times of the volume of deuterated methanol. Further, the aprotic solvent is selected from carbon tetrachloride, and the volume of the aprotic solvent is 5-10 times of the volume of the deuterated methanol. Further, the inert gas in the step 1) is nitrogen or argon. Further, the mole ratio of the deuterated methanol to the iodine simple substance in the step 1) is 1:1-3.5, and the mole ratio of the iron powder to the iodine simple substance is 0.5-2.5:1. Further, the molar ratio of deuterated methanol to iodine simple substance is 1:2-2.5, and the molar ratio of iron powder to iodine simple substance is 1.5-2:1. Further, the reaction temperature in the step 1) is 70-120 ℃ and the reaction time is 5-120min. Fur