A method for preparing deuterated chloroform

Abstract

The application provides a preparation method of deuterated chloroform (CCl3D). The method comprises the following steps: after deuterated methane and Cl2 are mixed in a photochemical reactor under the action of ultraviolet-visible light and a catalyst, deuterated chloroform is obtained through the treatment of alkali washing, liquid separation, drying and distillation in sequence. The method realizes the selective reaction of deuterated methane and chlorine under mild conditions by using a new type of high-efficiency catalyst and cooperating with a photochemical reactor. The raw material for producing the deuterated chloroform is easy to obtain, the preparation period is short, and the continuous production can be realized. In addition, the method also produces by-products such as deuterated monochloromethane and deuterated dichloromethane, which have certain application value, and further improves the economic benefits of the overall production process. The deuterated chloroform prepared by the application can not only improve the accuracy of analysis, enhance the repeatability and comparability of experiments, protect experimental equipment and samples, but also meet specific application requirements and improve product quality in practical application.

Description

Technical Field

[0001] This invention relates to the technical field of deuterated reagent preparation, and more particularly to a method for preparing deuterated chloroform (CCl3D). Background Technology

[0002] Isotope reagents occupy a pivotal position in the vast field of chemical science and technology. They are not only keys to exploring the mysteries of nature but also important tools driving modern industrial development. In the field of chemical synthesis, isotope reagents, by precisely labeling specific sites on target molecules, provide scientists with unprecedented perspectives, enabling in-depth and detailed studies of the mechanisms of complex chemical reactions. This capability has greatly facilitated the design and synthesis of new compounds and accelerated the process of drug discovery and optimization. In the field of analysis, isotope labeling technology has significantly improved detection sensitivity and specificity, providing strong support for research on in vivo substance transformation and metabolic pathway analysis.

[0003] Deuterated chloroform, as an important member of isotopic reagents, possesses unique chemical properties that endow it with broad application potential. As a solvent, deuterated chloroform can reduce background signals caused by hydrogen atom exchange, improving the resolution and accuracy of spectroscopic analysis techniques such as nuclear magnetic resonance (NMR). As an intermediate, it can cleverly introduce deuterium-labeled methyl groups, providing a convenient route for the preparation of specific deuterated compounds. These deuterated compounds exhibit unique advantages in drug stability studies and metabolite tracking.

[0004] However, current methods for preparing deuterated chloroform (CCl3D) primarily involve the decomposition of deuterated trichloroacetaldehyde in a heavy aqueous solution of deuterated sodium hydroxide. This method, however, is highly dependent on high-purity deuterated raw materials—deuterated sodium hydroxide and deuterated trichloroacetaldehyde. The complex and costly preparation of these raw materials not only prolongs the entire production cycle but also increases material costs.

[0005] Therefore, there is an urgent need to develop a more efficient and economical route for preparing deuterated chloroform (CCl3D) in order to obtain high-quality products while reducing production costs and shortening the production cycle. Summary of the Invention

[0006] In view of this, the present invention proposes a method for preparing deuterated chloroform (CCl3D) that is easy to obtain, has a short process flow, is simple to operate, can be continuously produced, and has certain economic value.

[0007] In a first aspect, the present invention provides a method for preparing deuterated chloroform (CCl3D), the method comprising: mixing deuterated methane and Cl2 in a photochemical reactor under the action of ultraviolet-visible light and a catalyst, and then sequentially subjecting the mixture to alkaline washing, separation, drying and distillation to obtain deuterated chloroform (CCl3D).

[0008] By adopting the above technical solution, the raw materials are readily available, the reaction conditions are mild, the reaction efficiency is high, and it is environmentally friendly and easy to operate.

[0009] Furthermore, the wavelength of the ultraviolet-visible light is 200–800 nm.

[0010] Furthermore, the catalyst is selected from anatase TiO2 doped with Ce, Zn, Ag, Cu and / or Mn ions.

[0011] By adopting the above technical solutions, not only can the synthesis efficiency of deuterated chloroform be improved, but also costs can be reduced and environmental pollution can be decreased.

[0012] Furthermore, the molar ratio of the deuterated methane to the Cl2 is (0.6–1.5):1.

[0013] By adopting the above technical solution, under the molar ratio set by the present invention, the reaction occurring in the reactor can be effectively controlled, so that the product is more inclined to the desired deuterated chloroform (such as CCl3D, deuterated monochloromethane, deuterated dichloromethane, etc.) rather than other by-products.

[0014] Furthermore, the photochemical reactor is a tubular photochemical reactor or a microchannel photochemical reactor; the inner diameter of the photochemical reactor is 0.1-6 mm, and the material is quartz or borosilicate glass.

[0015] Furthermore, the temperature inside the photochemical reactor is set to 20–200°C.

[0016] Furthermore, the residence time of the mixture of deuterated methane and Cl2 in the photochemical reactor is 0.2 to 1.5 s.

[0017] By adopting the above technical solutions, the selectivity of products can be optimized, ensuring that as many target products as possible are generated within a limited time, thereby improving production efficiency and reducing energy consumption.

[0018] Furthermore, in the alkaline washing process, the washing solution is selected from one of NaOH solution, Na2CO3 solution, K2CO3 solution or KOH solution.

[0019] Furthermore, during the drying process, the desiccant is selected from one of soda lime, Al2O3, or CaCl2.

[0020] Secondly, the present invention provides a deuterated chloroform (CCl3D) prepared as described above, wherein the deuterated chloroform (CCl3D) has a purity of not less than 98% and an abundance of not less than 99%.

[0021] By adopting the above technical solution, the deuterated chloroform (CCl3D) prepared by this invention can not only improve the accuracy of analysis, enhance the repeatability and comparability of experiments, and protect experimental equipment and samples in practical applications, but also meet specific application requirements and improve product quality.

[0022] The method for preparing deuterated chloroform provided by this invention has the following advantages over the prior art:

[0023] The raw materials for preparing deuterated chloroform (CCl3D) according to this invention are readily available, the preparation cycle is short, and continuous production is possible, which has high economic value.

[0024] This invention employs a novel, highly efficient catalyst in conjunction with tubular or microchannel photochemical reactor technology to prepare deuterated chloroform, achieving selective reaction of deuterated methane with chlorine under mild conditions. By precisely controlling the residence time of the reactants, the yield of the target product, deuterated chloroform (CCl3D), is effectively improved. Furthermore, this process also produces byproducts such as deuterated monochloromethane and deuterated dichloromethane, which have certain application value, further enhancing the overall economic efficiency of the production process.

[0025] The deuterated chloroform (CCl3D) prepared by this invention can not only improve the accuracy of analysis, enhance the repeatability and comparability of experiments, and protect experimental equipment and samples in practical applications, but also meet specific application requirements and improve product quality. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 Gas chromatogram of the deuterated chloroform product prepared in Example 1 of this invention;

[0028] Figure 2 The mass spectrum of the deuterated chloroform product prepared in Example 1 of this invention. Detailed Implementation

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] The present invention will be further described below with reference to specific embodiments. The scope of protection of the present invention is not limited to the following embodiments. The main sources of materials involved in the embodiments are shown in Table 1 below. Other materials not specified are conventional commercially available products.

[0031] Table 1 Material Source Description

[0032] Serial Number Material / Equipment Name Specifications / Model factory 1 Gas Chromatography-Mass Spectrometry GCMS24000SQ T PerkinElmer 2 Karl Fischer moisture analyzer AKF-3N Shanghai Hegong Scientific Instruments Co., Ltd. 3 chlorine >99.9％ Anhui Zesen Technology Co., Ltd. 4 Deuterated methane >99％ Wuhan Spectrum Isotope Technology Co., Ltd.

[0033] The photochemical reactors used in the following examples of this invention are all prepared by the following steps, specifically including:

[0034] (1) Tubular photochemical reactor

[0035] A quartz tube with an inner diameter of 6 mm and a length of 100 mm is filled with Ce and Zn ion-doped anatase TiO2 particles with a particle size of 20 mesh.

[0036] (2) Microchannel photochemical reactor

[0037] A heart-shaped microchannel photochemical reactor was used, made of quartz or borosilicate glass. The inner diameter of the reactor channel was 0.1–6 mm. Anatase TiO2 doped with Ce, Zn, Ag, Cu and / or Mn ions was mixed with water to form a suspension. The mass ratio of TiO2 to water in the suspension was 1:2. Nitric acid was added dropwise at 1 mm, and the mixture was then ground in a ball mill for 24 h to obtain the catalyst suspension.

[0038] After the catalyst suspension was coated inside the microchannel, the microchannel was purged with 6 bar high-pressure nitrogen gas.

[0039] After purging, the entire reactor was placed in a heating furnace and dried at 120°C for 4 hours, and then calcined at 250°C for 4 hours.

[0040] The preparation method of the TiO2 catalyst with doped ions mentioned in the following examples, taking Ce and Zn ion doping as an example, includes the following steps:

[0041] Take 50 ml of tetrabutyl titanate and slowly add it to 50 ml of anhydrous ethanol. Mix and stir until homogeneous to obtain a tetrabutyl titanate ethanol solution.

[0042] Take 0.1g of cerium nitrate and 0.1g of zinc nitrate, add 50ml of distilled water, then add 10ml of concentrated nitric acid and 20ml of anhydrous ethanol, stir until all solids are dissolved, add the resulting solution to tetrabutyl titanate ethanol solution, and stir continuously at room temperature for 5 hours to obtain a mixed solution.

[0043] The mixture was added to the reactor and heated at 140°C for 6 hours. After cooling, the upper clear liquid was removed, and the mixture was dried at 100°C for 2 hours. After crushing, it was placed in a high-temperature furnace at 550°C and calcined for 4 hours. After sieving, the finished product was obtained.

[0044] The following are embodiments of the present invention.

[0045] Example 1

[0046] This embodiment provides a method for preparing deuterated chloroform, including the following steps:

[0047] A quartz tube with an inner diameter of 6 mm and a length of 100 mm is filled with Ce and Zn ion-doped anatase TiO2 particles with a particle size of 20 mesh, which serves as a photochemical reactor for the preparation of deuterated chloroform.

[0048] The reactor was placed in a UV lamp chamber equipped with a heating system. The temperature inside the UV lamp chamber was 200°C and the UV-Vis wavelength was 400nm.

[0049] Deuterated methane and chlorine were mixed at a molar ratio of 1:1 to form a gas mixture. The gas mixture was then introduced into the reactor described above. The gas flow rate was controlled at 170 ml / min by a mass flow meter, corresponding to a residence time of 0.8 s.

[0050] The gas exiting the reactor is passed into a saturated sodium carbonate solution for alkaline washing. After standing and separating into layers, the lower layer is collected and passed into a drying column filled with CaCl2. After drying, crude deuterated chloroform is obtained.

[0051] Analysis revealed that the crude deuterated chloroform contained 78% deuterated chloroform, 19% deuterated dichloromethane, and 2% deuterated monochloromethane.

[0052] Crude deuterated chloroform was distilled, and the fraction collected at 58-64℃ was the deuterated chloroform. The purity of the prepared deuterated chloroform was determined using an Elliite-5 capillary column with an FID detector, with the injection port temperature set at 250℃, the column oven temperature at 60℃, and the detector temperature at 250℃. The purity was found to be 98%, and mass spectrometry analysis showed an abundance of 99%. The calculated overall chlorine conversion rate was 95%.

[0053] Combination Figure 1 , Figure 2It can be seen that the deuterated chloroform product prepared by this method has high purity, and its mass spectrum characteristics are consistent with those of deuterated chloroform, indicating that this method can prepare high-purity deuterated chloroform.

[0054] Example 2

[0055] This embodiment provides a method for preparing deuterated chloroform, including the following steps:

[0056] A quartz tube with an inner diameter of 6 mm and a length of 100 mm is filled with Cu and Zn ion-doped anatase TiO2 particles with a particle size of 20 mesh, which serves as a photochemical reactor for the preparation of deuterated chloroform.

[0057] The reactor was placed in a UV lamp chamber equipped with a heating system. The temperature inside the UV lamp chamber was 200°C and the UV-Vis wavelength was 400nm.

[0058] Deuterated methane and chlorine were mixed at a molar ratio of 1:1 to form a gas mixture. The gas mixture was then introduced into the reactor described above. The gas flow rate was controlled at 170 ml / min by a mass flow meter, corresponding to a residence time of 0.8 s.

[0059] The gas exiting the reactor is passed into a NaOH solution for alkaline washing, allowed to stand and separate into layers, and the lower layer is taken out. The lower layer is then passed into a drying column filled with soda lime, and after drying, crude deuterated chloroform is obtained.

[0060] Analysis revealed that the crude deuterated chloroform contained 75% deuterated chloroform, 21% deuterated dichloromethane, and 3% deuterated monochloromethane.

[0061] Crude deuterated chloroform was distilled, and the fraction collected at 58-64℃ was the deuterated chloroform. The purity of the prepared deuterated chloroform was determined using an Elliite-5 capillary column with an FID detector, with the injection port temperature set at 250℃, the column oven temperature at 60℃, and the detector temperature at 250℃. The purity was found to be 98%, and mass spectrometry analysis showed an abundance of 99%. The calculated overall chlorine conversion rate was 91%.

[0062] Example 3

[0063] This embodiment provides a method for preparing deuterated chloroform, including the following steps:

[0064] A quartz tube with an inner diameter of 6 mm and a length of 100 mm is filled with Mn ion-doped anatase TiO2 particles with a particle size of 20 mesh, which serves as a photochemical reactor for the preparation of deuterated chloroform.

[0065] The reactor was placed in a UV lamp chamber equipped with a heating system. The temperature inside the UV lamp chamber was 200°C and the UV-Vis wavelength was 400nm.

[0066] Deuterated methane and chlorine were mixed at a molar ratio of 1:1 to form a gas mixture. The gas mixture was then introduced into the reactor described above. The gas flow rate was controlled at 170 ml / min by a mass flow meter, corresponding to a residence time of 0.8 s.

[0067] The gas exiting the reactor is passed into a potassium carbonate solution for alkaline washing, allowed to stand and separate into layers, and the lower layer is taken out. The lower layer is then passed into a drying column filled with alumina and dried to obtain crude deuterated chloroform.

[0068] Analysis revealed that the crude deuterated chloroform contained 70% deuterated chloroform, 25% deuterated dichloromethane, and 4% deuterated monochloromethane.

[0069] Crude deuterated chloroform was distilled, and the fraction collected at 58-64℃ was the deuterated chloroform. The purity of the prepared deuterated chloroform was determined using an Elliite-5 capillary column with an FID detector, with the injection port temperature set at 250℃, the column oven temperature at 60℃, and the detector temperature at 250℃. The purity was found to be 98%, and mass spectrometry analysis showed an abundance of 99%. The calculated overall chlorine conversion rate was 85%.

[0070] Example 4

[0071] This embodiment provides a method for preparing deuterated chloroform, including the following steps:

[0072] An Ag ion-doped anatase TiO2 particles with a particle size of 20 mesh were filled into a quartz tube with an inner diameter of 6 mm and a length of 100 mm to serve as a photochemical reactor for the preparation of deuterated chloroform.

[0073] The reactor was placed in a UV lamp chamber equipped with a heating system. The temperature inside the UV lamp chamber was 200°C and the UV-Vis wavelength was 400nm.

[0074] Deuterated methane and chlorine were mixed at a molar ratio of 1:1 to form a gas mixture. The gas mixture was then introduced into the reactor described above. The gas flow rate was controlled at 170 ml / min by a mass flow meter, corresponding to a residence time of 0.8 s.

[0075] The gas from the reactor outlet is passed into a KOH solution for alkaline washing, allowed to stand and separate into layers, and the lower layer is taken out. The lower layer is then passed into a drying column filled with calcium chloride, and after drying, crude deuterated chloroform is obtained.

[0076] Analysis revealed that the crude deuterated chloroform contained 67% deuterated chloroform, 26% deuterated dichloromethane, and 4% deuterated monochloromethane.

[0077] Crude deuterated chloroform was distilled, and the fraction collected at 58-64℃ was the deuterated chloroform. The purity of the prepared deuterated chloroform was determined using an Elliite-5 capillary column with an FID detector, with the injection port temperature set to 250℃, the column oven temperature to 60℃, and the detector temperature to 250℃. The purity was found to be 98%, and mass spectrometry analysis showed an abundance of 99%. The calculated overall chlorine conversion rate was 81%.

[0078] Example 5

[0079] This embodiment provides a method for preparing deuterated chloroform, including the following steps:

[0080] A microchannel reactor with a feature size of 0.1 mm was used, and the interior was coated with anatase TiO2 particles doped with Ce and Zn ions.

[0081] The reactor was placed in a UV lamp chamber equipped with a heating system. The temperature inside the UV lamp chamber was 200°C and the UV-Vis wavelength was 400nm.

[0082] Deuterated methane and chlorine were mixed at a molar ratio of 1:1 to form a gas mixture. The gas mixture was then introduced into the reactor described above. The gas flow rate was controlled at 170 ml / min by a mass flow meter, corresponding to a residence time of 0.8 s.

[0083] The gas exiting the reactor is passed into a saturated sodium carbonate solution. After alkaline washing, the layers are separated. The lower layer is taken and passed into a drying column filled with CaCl2. After drying, crude deuterated chloroform is obtained.

[0084] Analysis revealed that the crude deuterated chloroform contained 82% deuterated chloroform, 14% deuterated dichloromethane, and 3% deuterated monochloromethane.

[0085] Crude deuterated chloroform was distilled, and the fraction collected at 58-64℃ was the deuterated chloroform. The purity of the prepared deuterated chloroform was determined using an Elliite-5 capillary column with an FID detector, with the injection port temperature set to 250℃, the column oven temperature to 60℃, and the detector temperature to 250℃. The purity was found to be 98%, and mass spectrometry analysis showed an abundance of 99%. Calculations showed that the overall chlorine conversion rate was 99%.

[0086] Example 6

[0087] This embodiment provides a method for preparing deuterated chloroform, including the following steps:

[0088] A quartz tube with an inner diameter of 6 mm and a length of 100 mm is filled with Ce and Zn ion-doped anatase TiO2 particles with a particle size of 20 mesh, which serves as a photochemical reactor for the preparation of deuterated chloroform.

[0089] The reactor was placed in a UV lamp chamber equipped with a heating system. The temperature inside the UV lamp chamber was 20°C and the UV-Vis wavelength was 400nm.

[0090] Deuterated methane and chlorine were mixed at a molar ratio of 1:1 to form a gas mixture. The gas mixture was then introduced into the reactor described above. The gas flow rate was controlled at 90 ml / min by a mass flow meter, corresponding to a residence time of 1.5 s.

[0091] The gas exiting the reactor is passed into a saturated sodium carbonate solution for alkaline washing. After standing and separating into layers, the lower layer is collected and passed into a drying column filled with CaCl2. After drying, crude deuterated chloroform is obtained.

[0092] Analysis revealed that the crude deuterated chloroform contained 79% deuterated chloroform, 15% deuterated dichloromethane, and 2% deuterated monochloromethane.

[0093] Crude deuterated chloroform was distilled, and the fraction collected at 58-64℃ was the deuterated chloroform. The purity of the prepared deuterated chloroform was determined using an Elliite-5 capillary column with an FID detector, with the injection port temperature set to 250℃, the column oven temperature to 60℃, and the detector temperature to 250℃. The purity was found to be 98%, and mass spectrometry analysis showed an abundance of 99%. The calculated overall chlorine conversion rate was 93%.

[0094] Example 7

[0095] This embodiment provides a method for preparing deuterated chloroform, including the following steps:

[0096] A quartz tube with an inner diameter of 6 mm and a length of 100 mm is filled with Ce and Zn ion-doped anatase TiO2 particles with a particle size of 20 mesh, which serves as a photochemical reactor for the preparation of deuterated chloroform.

[0097] The reactor was placed in a UV lamp chamber equipped with a heating system. The temperature inside the UV lamp chamber was 150°C and the UV-Vis wavelength was 400 nm.

[0098] Deuterated methane and chlorine were mixed at a molar ratio of 1:1 to form a gas mixture. The gas mixture was then introduced into the reactor described above. The gas flow rate was controlled at 680 ml / min by a mass flow meter, corresponding to a residence time of 0.2 s.

[0099] The gas exiting the reactor is passed into a saturated sodium carbonate solution for alkaline washing. After standing and separating into layers, the lower layer is collected and passed into a drying column filled with CaCl2. After drying, crude deuterated chloroform is obtained.

[0100] Analysis revealed that the crude deuterated chloroform contained 80% deuterated chloroform, 16% deuterated dichloromethane, and 3% deuterated monochloromethane.

[0101] Crude deuterated chloroform was distilled, and the fraction collected at 58-64℃ was obtained as deuterated chloroform. The purity of the prepared deuterated chloroform was determined using an Elliite-5 capillary column with an FID detector, with the injection port temperature set to 250℃, the column oven temperature to 60℃, and the detector temperature to 250℃. The purity was found to be 98%, and mass spectrometry analysis showed an abundance of 99%. The calculated overall chlorine conversion rate was 68%.

[0102] Example 8

[0103] This embodiment provides a method for preparing deuterated chloroform, including the following steps:

[0104] A quartz tube with an inner diameter of 6 mm and a length of 100 mm is filled with Ce and Zn ion-doped anatase TiO2 particles with a particle size of 20 mesh, which serves as a photochemical reactor for the preparation of deuterated chloroform.

[0105] The reactor was placed in a UV lamp chamber equipped with a heating system. The temperature inside the UV lamp chamber was 20°C and the UV-Vis wavelength was 200nm.

[0106] Deuterated methane and chlorine were mixed at a molar ratio of 1:1 to form a gas mixture. The gas mixture was then introduced into the reactor described above. The gas flow rate was controlled at 170 ml / min by a mass flow meter, corresponding to a residence time of 0.8 s.

[0107] The gas exiting the reactor is passed into a saturated sodium carbonate solution for alkaline washing. After standing and separating into layers, the lower layer is collected and passed into a drying column filled with CaCl2. After drying, crude deuterated chloroform is obtained.

[0108] Analysis revealed that the crude deuterated chloroform contained 67% deuterated chloroform, 23% deuterated dichloromethane, and 7% deuterated monochloromethane.

[0109] Crude deuterated chloroform was distilled, and the fraction collected at 58-64℃ was the deuterated chloroform. The purity of the prepared deuterated chloroform was determined using an Elliite-5 capillary column with an FID detector, with the injection port temperature set to 250℃, the column oven temperature to 60℃, and the detector temperature to 250℃. The purity was found to be 98%, and mass spectrometry analysis showed an abundance of 99%. The calculated overall chlorine conversion rate was 76%.

[0110] Example 9

[0111] This embodiment provides a method for preparing deuterated chloroform, including the following steps:

[0112] A quartz tube with an inner diameter of 6 mm and a length of 100 mm is filled with Ce and Zn ion-doped anatase TiO2 particles with a particle size of 20 mesh, which serves as a photochemical reactor for the preparation of deuterated chloroform.

[0113] The reactor was placed in a UV lamp chamber equipped with a heating system. The temperature inside the UV lamp chamber was 20°C and the UV-Vis wavelength was 800nm.

[0114] Deuterated methane and chlorine were mixed at a molar ratio of 1:1 to form a gas mixture. The gas mixture was then introduced into the reactor described above. The gas flow rate was controlled at 170 ml / min by a mass flow meter, corresponding to a residence time of 0.8 s.

[0115] The gas exiting the reactor is passed into a saturated sodium carbonate solution for alkaline washing. After standing and separating into layers, the lower layer is collected and passed into a drying column filled with CaCl2. After drying, crude deuterated chloroform is obtained.

[0116] Analysis revealed that the crude deuterated chloroform contained 65% deuterated chloroform, 24% deuterated dichloromethane, and 8% deuterated monochloromethane.

[0117] Crude deuterated chloroform was distilled, and the fraction collected at 58-64℃ was obtained as deuterated chloroform. The purity of the prepared deuterated chloroform was determined using an Elliite-5 capillary column with an FID detector, with the injection port temperature set at 250℃, the column oven temperature at 60℃, and the detector temperature at 250℃. The purity was found to be 98%, and mass spectrometry analysis showed an abundance of 99%. The calculated overall chlorine conversion rate was 71%.

[0118] Example 10

[0119] This embodiment provides a method for preparing deuterated chloroform, including the following steps:

[0120] A quartz tube with an inner diameter of 6 mm and a length of 100 mm is filled with Ce and Zn ion-doped anatase TiO2 particles with a particle size of 20 mesh, which serves as a photochemical reactor for the preparation of deuterated chloroform.

[0121] The reactor was placed in a UV lamp chamber equipped with a heating system. The temperature inside the UV lamp chamber was 20°C and the UV-Vis wavelength was 400nm.

[0122] Deuterated methane and chlorine were mixed at a molar ratio of 0.6:1 to form a gas mixture. The gas mixture was then introduced into the reactor described above. The gas flow rate was controlled at 170 ml / min by a mass flow meter, corresponding to a residence time of 0.8 s.

[0123] The gas exiting the reactor is passed into a saturated sodium carbonate solution for alkaline washing. After standing and separating into layers, the lower layer is collected and passed into a drying column filled with CaCl2. After drying, crude deuterated chloroform is obtained.

[0124] Analysis revealed that the crude deuterated chloroform contained 65% deuterated chloroform, 23% deuterated dichloromethane, and 10% carbon tetrachloride.

[0125] Crude deuterated chloroform was distilled, and the fraction collected at 58-64℃ was obtained as deuterated chloroform. The purity of the prepared deuterated chloroform was determined using an Elliite-5 capillary column with an FID detector, with the injection port temperature set at 250℃, the column oven temperature at 60℃, and the detector temperature at 250℃. The purity was found to be 98%, and mass spectrometry analysis showed an abundance of 99%. The calculated overall chlorine conversion rate was 80%.

[0126] Example 11

[0127] This embodiment provides a method for preparing deuterated chloroform, including the following steps:

[0128] A quartz tube with an inner diameter of 6 mm and a length of 100 mm is filled with Ce and Zn ion-doped anatase TiO2 particles with a particle size of 20 mesh, which serves as a photochemical reactor for the preparation of deuterated chloroform.

[0129] The reactor was placed in a UV lamp chamber equipped with a heating system. The temperature inside the UV lamp chamber was 20°C and the UV-Vis wavelength was 400nm.

[0130] Deuterated methane and chlorine were mixed at a molar ratio of 1.5:1 to form a gas mixture. The gas mixture was then introduced into the reactor described above. The gas flow rate was controlled at 170 ml / min by a mass flow meter, corresponding to a residence time of 0.8 s.

[0131] The gas exiting the reactor is passed into a saturated sodium carbonate solution for alkaline washing. After standing and separating into layers, the lower layer is collected and passed into a drying column filled with CaCl2. After drying, crude deuterated chloroform is obtained.

[0132] Analysis revealed that the crude deuterated chloroform contained 19% deuterated chloroform, 14% deuterated dichloromethane, and 2% deuterated monochloromethane.

[0133] Crude deuterated chloroform was distilled, and the fraction collected at 58-64℃ was the deuterated chloroform. The purity of the prepared deuterated chloroform was determined using an Elliite-5 capillary column with an FID detector, with the injection port temperature set to 250℃, the column oven temperature to 60℃, and the detector temperature to 250℃. The purity was found to be 98%, and mass spectrometry analysis showed an abundance of 99%. The calculated overall chlorine conversion rate was 96%.

[0134] The following is a comparative example of this application.

[0135] Comparative Example 1

[0136] The difference from Example 1 is that the deuterated methane and the chlorine are mixed in a molar ratio of 0.3:1, while the other conditions remain unchanged.

[0137] Analysis revealed that the crude deuterated chloroform contained 58% deuterated chloroform, 2% deuterated dichloromethane, and 40% carbon tetrachloride.

[0138] Crude deuterated chloroform was distilled, and the fraction collected at 58-64℃ was the deuterated chloroform. The purity of the prepared deuterated chloroform was determined using an Elliite-5 capillary column with an FID detector, with the injection port temperature set at 250℃, the column oven temperature at 60℃, and the detector temperature at 250℃. The purity was found to be 99%. Mass spectrometry analysis showed an abundance of 99%. Calculations showed that the overall chlorine conversion rate was 90%.

[0139] Comparative Example 2

[0140] The difference from Example 1 is that the mixed gas is passed through the reactor, and the gas flow rate is controlled at 24 ml / min by a mass flow meter, corresponding to a residence time of 4 s, while the other conditions remain unchanged.

[0141] Analysis revealed that the crude deuterated chloroform contained 38% deuterated chloroform, 2% deuterated dichloromethane, and 60% carbon tetrachloride.

[0142] Crude deuterated chloroform was distilled, and the fraction collected at 58-64℃ was obtained as deuterated chloroform. The purity of the prepared deuterated chloroform was determined using an Elliite-5 capillary column with an FID detector, with the injection port temperature set at 250℃, the column oven temperature at 60℃, and the detector temperature at 250℃. The purity was found to be 99%. Mass spectrometry analysis showed an abundance of 99%. The calculated overall chlorine conversion rate was 97%.

[0143] Comparative Example 3

[0144] The difference from Example 1 is that the gas at the reactor outlet was not alkali washed, while the other conditions remained unchanged.

[0145] The crude deuterated chloroform was titrated with NaOH solution, and the HCl and Cl2 content (converted to HCl) was determined to be approximately 8%. The crude deuterated chloroform was also distilled, and the fraction collected at 58-64℃ was the deuterated chloroform. Titration of this product with NaOH solution yielded an HCl and Cl2 content (converted to HCl) of approximately 2%.

[0146] After neutralizing the deuterated chloroform product with sodium carbonate, the purity of the prepared deuterated chloroform was tested using an Ellite-5 capillary column and an FID detector, with the injection port temperature set to 250℃, the column oven temperature to 60℃, and the detector temperature to 250℃. The purity was found to be 93%.

[0147] Comparative Example 4

[0148] The difference from Example 1 is that the lower liquid was not dried, while the other conditions remained the same.

[0149] Crude deuterated chloroform was distilled, and the fraction collected at 58-64℃ was the deuterated chloroform. During distillation, the distillate was turbid. The purity of the obtained deuterated chloroform was determined using an Elliite-5 capillary column with an FID detector, set to an injection port temperature of 250℃, a column oven temperature of 60℃, and a detector temperature of 250℃. The purity was found to be 90%. Titration with NaOH solution revealed that the HCl and Cl2 content (converted to HCl) was approximately 0.2%. A Karl Fischer moisture analyzer was used to determine the moisture content of the sample, which was approximately 2%.

[0150] Based on the detection results of Examples 1-11 and Comparative Examples 1-4 above, we can conclude that:

[0151] (1) Combining Example 1 and Comparative Example 1, it can be seen that increasing the molar ratio of Cl2 to deuterated methane results in a large amount of carbon tetrachloride in the product, significantly reducing the yield of deuterated chloroform. Furthermore, since CD4 in the reaction tail gas needs to be recovered, the increased residual chlorine content in the tail gas will increase the consumption of alkali solution during the alkaline washing process, which is detrimental to the subsequent recycling and recovery of unreacted CD4. Decreasing the molar ratio of Cl2 to deuterated methane can reduce the amount of residual chlorine in the tail gas and the amount of carbon tetrachloride in the product, but it will significantly increase the amount of CD4 recycled. A comparison between Example 1 and Example 10 shows that when the molar ratio of Cl2 to deuterated methane is above 1.5, the effect on improving the chlorine conversion rate and the purity of deuterated chlorine is not significant. Therefore, controlling the molar ratio of Cl2 to deuterated methane between 1:(0.6~1.5) is appropriate.

[0152] (2) Combining Example 1 and Comparative Example 2, it can be seen that if the residence time of the material is extended, although the conversion rate of deuterated methane is improved, the product contains a large amount of carbon tetrachloride. Carbon tetrachloride is not a deuterated reagent, and the increase of carbon tetrachloride will greatly reduce the yield of deuterated chloroform.

[0153] (3) Combining Example 1 and Comparative Example 3, it can be seen that: because the gas (i.e., the reaction product) at the reactor outlet of Comparative Example 3 was not washed with alkali, the product contained acidic gases such as chlorine and hydrogen chloride. The presence of acidic gases would cause the subsequent deuterated methane to be acidic, reducing the purity of the deuterated methane product. This limits its application in the analytical field. At the same time, because the deuterated methane tail gas contains acidic gases, it is easy to corrode the equipment, which is not conducive to the subsequent recovery and utilization of deuterated methane.

[0154] (4) As can be seen from Example 1 and Comparative Example 4, since the lower liquid obtained from the separation in Comparative Example 4 was not dried, water and crude deuterated chloroform were distilled off together during the subsequent distillation process, resulting in a turbid distillate. This leads to a high water content in the product, which can cause interference with the analytical results when the product is used as a reagent for NMR analysis.

[0155] (5) By comparing Example 1 and Example 5, it can be seen that the yield of the reaction and the yield of deuterated chloroform can be further improved by using a microchannel reactor.

[0156] (6) By comparing Example 1 with Examples 8 and 9, it can be seen that the photocatalytic wavelength suitable for this reaction is 200-800nm, and the conversion rate of the reaction can reach the optimal value around 400nm.

[0157] (7) As can be seen from the comparison of Examples 1-4, different ion doping can improve the catalyst efficiency, and multi-component doping is better than single-component doping.

[0158] In summary, by controlling the appropriate ratio of Cl2 to deuterated methane to ensure that deuterated methane is in excess, and by purifying the crude deuterated chloroform through alkaline washing and absorption processes, the abundance and purity of deuterated chloroform are guaranteed.

[0159] Based on the above embodiments, the inventors further optimized the reaction process to obtain Example 12, which includes the following steps:

[0160] 1) Reaction:

[0161] A quartz tube with an inner diameter of 6 mm and a length of 100 mm is filled with Ce and Zn ion-doped anatase TiO2 particles with a particle size of 20 mesh, which serves as a photochemical reactor for the preparation of deuterated chloroform.

[0162] The reactor was placed in a UV lamp chamber equipped with a heating system. The temperature inside the UV lamp chamber was 200°C and the UV-Vis wavelength was 400nm.

[0163] Deuterated methane and chlorine were mixed at a molar ratio of 1:1 to form a gas mixture. The gas mixture was then introduced into the reactor described above. The gas flow rate was controlled at 170 ml / min by a mass flow meter, corresponding to a residence time of 0.8 s.

[0164] 2) Purification

[0165] The gas exiting the reactor is passed into a saturated sodium carbonate solution for alkaline washing. After standing and separating into layers, the lower layer is collected and passed into a drying column filled with CaCl2. After drying, crude deuterated chloroform is obtained.

[0166] 3) Semi-heavy water recycling

[0167] During the purification process, the pH value of the saturated sodium carbonate solution is measured. When it changes to 5-6, the aeration is stopped, and the sodium carbonate solution that has absorbed DCl is sent to an evaporator to evaporate to dryness. The condensate collected is semi-heavy water. The semi-heavy water is then sent to a heavy water distillation column to obtain heavy water.

[0168] 4) Deuterated methane recovery

[0169] The tail gas obtained after the reactor gas passes through a saturated sodium carbonate solution is compressed into a steel cylinder by a compressor to recover deuterated methane, which is then mixed with chlorine gas in the next batch of reaction and used as a feed gas.

[0170] The recovery of deuterated methane can achieve the recycling and utilization of deuterated methane, with a conversion rate of over 95%.

[0171] Recovering the semi-heavy water from a saturated sodium carbonate solution allows for the recovery of D elements converted to DCl during the reaction, avoiding the emission of D atoms and further improving economic efficiency.

[0172] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing deuterated chloroform, characterized in that, The method includes: Under the action of ultraviolet-visible light and a catalyst, deuterated methane and Cl2 are mixed in a photochemical reactor and then subjected to alkali washing, separation, drying and distillation to obtain deuterated chloroform. The catalyst is selected from anatase TiO2 doped with Ce, Zn, Ag, Cu and / or Mn ions.

2. The preparation method according to claim 1, characterized in that, The wavelength of the ultraviolet-visible light is 200~800nm.

3. The preparation method according to claim 1, characterized in that, The molar ratio of the deuterated methane to the Cl2 is (0.6~1.5):

1.

4. The preparation method according to claim 1, characterized in that, The photochemical reactor is a tubular photochemical reactor or a microchannel photochemical reactor; the inner diameter of the photochemical reactor is 0.1~6mm, and the material is quartz or borosilicate glass.

5. The preparation method according to claim 1, characterized in that, The temperature inside the photochemical reactor is set to 20~200℃.

6. The preparation method according to claim 1, characterized in that, The residence time of the mixture of deuterated methane and Cl2 in the photochemical reactor is 0.2~1.5s.

7. The preparation method according to claim 1, characterized in that, In the alkaline washing process, the washing solution is selected from one of NaOH solution, Na2CO3 solution, K2CO3 solution or KOH solution.

8. The preparation method according to claim 1, characterized in that, In the drying process, the desiccant is selected from one of soda lime, Al2O3 or CaCl2.

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