Method for preparing deuterated methanol and recycling tail gas

Abstract

The invention discloses a method for preparing deuterated methanol and recycling tail gas, and belongs to the technical field of organic synthesis. The deuterated methanol is synthesized under the catalytic reaction of mixed gas of deuterium gas and carbon monoxide, high temperature and high pressure and a catalyst. After the catalytic reaction is completed, the deuterated methanol is purified through condensation and distillation, reaction tail gas is subjected to palladium membrane gas purification, and the purified deuterium gas enters a deuterium gas storage tank to be recycled. According to the method, the amount of deuterium in the reaction process is increased, so that the conversion per pass of carbon monoxide in the synthesis reaction is increased, efficient preparation of deuterated methanol is achieved, meanwhile, deuterated methanol tail gas is recycled through palladium membrane purification, the utilization rate of the deuterium is increased, and the reaction cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis and relates to a method for preparing deuterated methanol and recycling tail gas. Background Art

[0002] Deuterated compounds refer to new compounds formed by replacing one or some hydrogen atoms in a compound molecule with deuterium atoms. They are widely used in the fields of fine chemicals, biomedicine, optoelectronic display, and nuclear magnetic resonance detection. Deuterated methanol is an important deuterated reagent with a molecular formula of CD3OD. Deuterated methanol (CD3OD) is prepared by replacing hydrogen (H) in methanol molecules (CH3OH) with its isotope deuterium (D). Deuterated methanol is one of the most widely used solvents in nuclear magnetic resonance spectroscopy, and is also an important raw material for deuterated compounds and an intermediate for deuterated drugs.

[0003] At present, deuterated methanol is mainly prepared by catalytic reduction from synthesis gas (deuterium gas, carbon monoxide). The prior art CN112321388A, CN11116313A, CN108250041A, CN115920973A, and CN116082121B all disclose methods for preparing deuterated methanol using deuterium gas and carbon monoxide gas as raw materials. However, the existing deuterated methanol preparation process has the problems of harsh reaction conditions, low process per-pass conversion rate, low deuterium gas utilization rate, and high cost. The main causes of the above problems include: unreacted synthesis tail gas in the synthesis of deuterated methanol will return to the synthesis unit as circulating gas, and the by-products (deuterated methane, deuterated dimethyl ether) contained in the tail gas will accumulate to a certain extent and affect the reaction conversion rate, the raw material gas deuterium gas price in the deuterated methanol synthesis process is relatively expensive, and the deuterium gas in the deuterated methanol tail gas is not fully recycled, etc. CN112850647A discloses a deuterated methanol purge gas recovery system, which requires a two-stage membrane separation unit and a pressure swing adsorption separation unit to cooperate under high pressure conditions for recovery. The complex process limits the industrial production of deuterated methanol. Therefore, it is urgent to develop a method for efficiently preparing deuterated methanol and simultaneously solve the problem of deuterium gas recovery in the purge gas, so as to reduce the industrial production cost of deuterated methanol. Summary of the invention

[0004] The present invention aims to solve the problems and defects of low per-pass conversion rate and low deuterium gas utilization rate in the prior art of deuterated methanol synthesis. The present invention provides a method for preparing deuterated methanol and recycling tail gas, which improves the per-pass conversion rate of carbon monoxide in the reaction by increasing the amount of deuterium gas used in the reaction process, thereby achieving efficient preparation of deuterated methanol, and at the same time recovering the deuterated methanol tail gas through a palladium membrane gas purification device, effectively solving the problems of low deuterium gas utilization rate and high cost.

[0005] The present invention provides a method for preparing deuterated methanol and recycling tail gas, comprising: reacting deuterium gas and carbon monoxide under temperature, pressure and catalyst conditions to generate deuterated methanol; at the same time, purifying the tail gas generated by the reaction to obtain purified deuterium gas; the purified deuterium gas enters a deuterium gas storage tank to participate in the preparation of deuterated methanol again;

[0006] The mass ratio of deuterium gas to carbon monoxide is 2.5 to 20:1;

[0007] The catalyst is a mixture of copper oxide, zinc oxide and aluminum oxide.

[0008] Furthermore, in the method for preparing deuterated methanol and recycling tail gas provided by the present invention, the temperature is 200-280°C.

[0009] Furthermore, in the method for preparing deuterated methanol and recycling tail gas provided by the present invention, the pressure is 3 to 6 MPa.

[0010] Furthermore, in the method for preparing deuterated methanol and recycling tail gas provided by the present invention, the mass ratio of copper oxide, zinc oxide and aluminum oxide is 6 to 7:2 to 3:1.

[0011] Furthermore, in the method for preparing deuterated methanol and recycling tail gas provided by the present invention, the catalyst is mixed with alumina ceramic balls and filled into a synthesis device to form a catalyst layer.

[0012] Furthermore, in the method for preparing deuterated methanol and recycling tail gas provided by the present invention, the mass ratio of the catalyst to the alumina ceramic ball is 1-2:1-2.

[0013] Furthermore, in the method for preparing deuterated methanol and recycling tail gas provided by the present invention, the flow rate of the mixed gas of deuterium gas and carbon monoxide is 20 to 200 L / min.

[0014] Furthermore, in the method for preparing deuterated methanol and recycling tail gas provided by the present invention, the tail gas is purified by passing through a palladium membrane.

[0015] Furthermore, in the method for preparing deuterated methanol and recycling tail gas provided by the present invention, the reaction time for generating deuterated methanol is 1 to 30 days.

[0016] Compared with the prior art, the technical solution provided by the present invention has at least the following beneficial effects or advantages:

[0017] The present invention effectively reduces the generation of impurity gases during the reaction process by increasing the amount of deuterium gas in the synthesis gas, significantly improves the reaction conversion rate, and enables the single-pass conversion rate to be stabilized at a high level of more than 95%. On this basis, high-quality deuterated methanol can be easily obtained by simply adopting a simple distillation purification step.

[0018] The present invention utilizes a palladium membrane gas purification device to recover and purify deuterium gas. The palladium membrane gas purification device has high selectivity and high recovery rate, and can achieve high-efficiency purification characteristics under low pressure conditions, solving the problem of recovering excess deuterium gas in the deuterated methanol synthesis reaction. The device can achieve a deuterium gas recovery rate of more than 98%, greatly improving the comprehensive utilization rate of deuterium gas and achieving a significant reduction in cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a process diagram for synthesizing deuterated methanol and recycling tail gas. 1 is the reaction gas premixing tank; 2 is the synthesis device; 3 is the condensation device; 4 is the distillation device; 5 is the tail gas storage tank; 6 is the palladium membrane gas purification device; and 7 is the deuterium gas storage tank. DETAILED DESCRIPTION

[0020] The technical scheme of the present invention is described below in conjunction with the embodiments, but the present invention is not limited to the following embodiments. The experimental methods and detection methods described in each embodiment are conventional methods unless otherwise specified; the reagents and materials described are all commercially available unless otherwise specified.

[0021] Example 1

[0022] This embodiment provides a method for synthesizing deuterated methanol and recycling tail gas.

[0023] like Figure 1 As shown, copper oxide, zinc oxide, and aluminum oxide are made into catalysts; the catalyst and inert aluminum oxide ceramic balls (purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.) are mixed and loaded into a synthesis device in a mass ratio of 1 to 2:1 to 2 to form a catalyst layer, and then a mixed gas of deuterium gas and carbon monoxide is introduced into the synthesis device for catalytic reaction under high temperature and high pressure for 1 to 30 days. During the reaction, deuterated methanol is liquefied by a condensing device and then enters a distillation device for purification, the reaction tail gas is temporarily stored in a storage tank, and then purified by a palladium membrane gas purification device, and the purified deuterium gas enters a deuterium gas storage tank for recycling.

[0024] Example 2

[0025] This embodiment provides a method for synthesizing deuterated methanol and recycling tail gas.

[0026] CuO, ZnO and Al2O3 are mixed evenly in a mass ratio of 6:3:1 to obtain a catalyst. The catalyst and inert alumina ceramic balls are mixed and loaded into a synthesis device in a mass ratio of 2:1 to form a catalyst layer. Deuterium gas and carbon monoxide are prepared into a mixed gas in a molar ratio of 2.5:1. The mixed gas enters the synthesis device at a speed of 100L / min under a pressure of 3MPa. The temperature of the synthesis device is controlled at 200±5℃, and the reaction is continuously circulated for 24 hours under the catalysis of the catalyst layer. During the reaction, deuterated methanol liquid is obtained by condensation. The deuterated methanol liquid is distilled and purified in a distillation device. The reaction tail gas enters a relaxation gas storage tank, and then is purified by a palladium membrane gas purification device. The purified deuterium gas enters a deuterium gas storage tank for recycling.

[0027] The single-pass conversion rate was measured to be 95.5% in terms of carbon monoxide. The purity of the collected deuterated methanol liquid after distillation could reach 99.2%. The recovery rate of deuterium gas in the purge gas was 98.5%.

[0028] Example 3

[0029] This embodiment provides a method for synthesizing deuterated methanol and recycling tail gas.

[0030] CuO, ZnO and Al2O3 are mixed evenly in a mass ratio of 6:3:1 to obtain a catalyst. The catalyst and inert alumina ceramic balls are mixed and loaded into a synthesis device in a mass ratio of 2:1 to form a catalyst layer. Deuterium gas and carbon monoxide are prepared into a mixed gas in a molar ratio of 5:1. The mixed gas enters the synthesis device at a speed of 100L / min under a pressure of 3MPa. The temperature of the synthesis device is controlled at 200±5℃, and the reaction is continuously circulated for 24 hours under the catalysis of the catalyst layer. During the reaction, deuterated methanol liquid is obtained by condensation. The deuterated methanol liquid is distilled and purified in a distillation device. The reaction tail gas enters a relaxation gas storage tank, and then is purified by a palladium membrane gas purification device. The purified deuterium gas enters a deuterium gas storage tank for recycling.

[0031] The single-pass conversion rate was measured to be 96.8% in terms of carbon monoxide. The purity of the collected deuterated methanol liquid after distillation could reach 99.3%. The deuterium recovery rate in the purge gas was 98.3%.

[0032] Example 4

[0033] This embodiment provides a method for synthesizing deuterated methanol and recycling tail gas.

[0034] CuO, ZnO and Al2O3 are mixed evenly in a mass ratio of 6:3:1 to obtain a catalyst. The catalyst and inert alumina ceramic balls are mixed and loaded into a synthesis device in a mass ratio of 2:1 to form a catalyst layer. Deuterium gas and carbon monoxide are prepared into a mixed gas in a molar ratio of 7.5:1. The mixed gas enters the synthesis device at a speed of 100L / min under a pressure of 3MPa. The temperature of the synthesis device is controlled at 200±5℃, and the reaction is continuously circulated for 24 hours under the catalysis of the catalyst layer. During the reaction, deuterated methanol liquid is obtained by condensation. The deuterated methanol liquid is distilled and purified in a distillation device. The reaction tail gas enters a relaxation gas storage tank, and then is purified by a palladium membrane gas purification device. The purified deuterium gas enters a deuterium gas storage tank for recycling.

[0035] The single-pass conversion rate measured in terms of carbon monoxide is 98.8%, the purity of the collected deuterated methanol liquid can reach 99.5% after distillation, and the deuterium recovery rate in the purge gas is 98.8%.

[0036] Example 5

[0037] This embodiment provides a method for synthesizing deuterated methanol and recycling tail gas.

[0038] CuO, ZnO and Al2O3 are mixed evenly in a mass ratio of 6:3:1 to obtain a catalyst. The catalyst and inert alumina ceramic balls are mixed and loaded into a synthesis device in a mass ratio of 2:1 to form a catalyst layer. Deuterium gas and carbon monoxide are prepared into a mixed gas in a molar ratio of 15:1. The mixed gas enters the synthesis device at a speed of 100L / min under a pressure of 3MPa. The temperature of the synthesis device is controlled at 200±5℃, and the reaction is continuously circulated for 24 hours under the catalysis of the catalyst layer. During the reaction, deuterated methanol liquid is obtained by condensation. The deuterated methanol liquid is distilled and purified in a distillation device. The reaction tail gas enters a relaxation gas storage tank, and then is purified by a palladium membrane gas purification device. The purified deuterium gas enters a deuterium gas storage tank for recycling.

[0039] The single-pass conversion rate was measured to be 99.2% in terms of carbon monoxide. The purity of the collected deuterated methanol liquid after distillation could reach 99.5%. The deuterium recovery rate in the purge gas was 98.5%.

[0040] Example 6

[0041] This embodiment provides a method for synthesizing deuterated methanol and recycling tail gas.

[0042] CuO, ZnO and Al2O3 are mixed evenly in a mass ratio of 6:3:1 to obtain a catalyst. The catalyst and inert alumina ceramic balls are mixed in a mass ratio of 2:1 and loaded into a synthesis device to form a catalyst layer. Deuterium gas and carbon monoxide are prepared into a mixed gas in a molar ratio of 20:1. The mixed gas enters the synthesis device at a speed of 100L / min under a pressure of 3MPa. The temperature of the synthesis device is controlled at 200±5℃, and the reaction is continuously circulated for 24 hours under the catalysis of the catalyst layer. During the reaction, deuterated methanol liquid is obtained by condensation. The deuterated methanol liquid is distilled and purified in a distillation device. The reaction tail gas enters a relaxation gas storage tank, and then is purified by a palladium membrane gas purification device. The purified deuterium gas enters a deuterium gas storage tank for recycling.

[0043] The single-pass conversion rate was measured to be 96.8% in terms of carbon monoxide. The purity of the collected deuterated methanol liquid after distillation could reach 99.6%. The recovery rate of deuterium gas in the purge gas was 99.0%.

[0044] Example 7

[0045] This embodiment provides a method for synthesizing deuterated methanol and recycling tail gas.

[0046] CuO, ZnO and Al2O3 are mixed evenly in a mass ratio of 7:2:1 to obtain a catalyst. The catalyst and inert alumina ceramic balls are mixed and loaded into a synthesis device in a mass ratio of 2:1 to form a catalyst layer. Deuterium gas and carbon monoxide are prepared into a mixed gas in a molar ratio of 7.5:1. The mixed gas enters the synthesis device at a speed of 100L / min under a pressure of 4.5MPa. The temperature of the synthesis device is controlled at 275±5℃, and the reaction is continuously circulated for 24 hours under the catalysis of the catalyst layer. During the reaction, deuterated methanol liquid is obtained by condensation. The deuterated methanol liquid is distilled and purified in a distillation device. The reaction tail gas enters a relaxation gas storage tank, and then is purified by a palladium membrane gas purification device. The purified deuterium gas enters a deuterium gas storage tank for recycling.

[0047] The single-pass conversion rate was measured to be 95.5% in terms of carbon monoxide. The purity of the collected deuterated methanol liquid after distillation could reach 99.8%. The deuterium recovery rate in the purge gas was 98.1%.

[0048] Example 8

[0049] This embodiment provides a method for synthesizing deuterated methanol and recycling tail gas.

[0050] CuO, ZnO and Al2O3 are mixed evenly in a mass ratio of 7:2:1 to obtain a catalyst. The catalyst and inert alumina ceramic balls are mixed and loaded into a synthesis device in a mass ratio of 2:1 to form a catalyst layer. Deuterium gas and carbon monoxide are prepared into a mixed gas in a molar ratio of 7.5:1. The mixed gas enters the synthesis device at a speed of 100L / min under a pressure of 6MPa. The temperature of the synthesis device is controlled at 275±5℃, and the reaction is continuously circulated for 24 hours under the catalysis of the catalyst layer. During the reaction, deuterated methanol liquid is obtained by condensation. The deuterated methanol liquid is distilled and purified in a distillation device. The reaction tail gas enters a relaxation gas storage tank, and then is purified by a palladium membrane gas purification device. The purified deuterium gas enters a deuterium gas storage tank for recycling.

[0051] The single-pass conversion rate was measured to be 96.5% in terms of carbon monoxide. The purity of the collected deuterated methanol liquid after distillation could reach 99.5%. The deuterium recovery rate in the purge gas was 98.3%.

[0052] Example 9

[0053] This embodiment provides a method for synthesizing deuterated methanol and recycling tail gas.

[0054] CuO, ZnO and Al2O3 are mixed evenly in a mass ratio of 7:2:1 to obtain a catalyst. The catalyst and inert alumina ceramic balls are mixed and loaded into a synthesis device in a mass ratio of 2:1 to form a catalyst layer. Deuterium gas and carbon monoxide are prepared into a mixed gas in a molar ratio of 15:1, and the mixed gas enters the synthesis device at a speed of 100L / min under a pressure of 4.5MPa. The temperature of the synthesis device is controlled at 275±5℃, and the reaction is continuously circulated for 24 hours under the catalysis of the catalyst layer. During the reaction, deuterated methanol liquid is obtained by condensation, and the deuterated methanol liquid is distilled and purified in a distillation device. The reaction tail gas enters the relaxation gas storage tank, and then is purified by a palladium membrane gas purification device. The purified deuterium gas enters the deuterium gas storage tank for recycling.

[0055] The single-pass conversion rate was measured to be 98.5% in terms of carbon monoxide. The purity of the collected deuterated methanol liquid after distillation could reach 99.7%. The recovery rate of deuterium gas in the purge gas was 98.8%.

[0056] Example 10

[0057] This embodiment provides a method for synthesizing deuterated methanol and recycling tail gas.

[0058] CuO, ZnO and Al2O3 are mixed evenly in a mass ratio of 7:2:1 to obtain a catalyst. The catalyst and inert alumina ceramic balls are mixed and loaded into a synthesis device in a mass ratio of 2:1 to form a catalyst layer. Deuterium gas and carbon monoxide are prepared into a mixed gas in a molar ratio of 15:1. The mixed gas enters the synthesis device at a speed of 100L / min under a pressure of 6MPa. The temperature of the synthesis device is controlled at 275±5℃, and the reaction is continuously circulated for 24 hours under the catalysis of the catalyst layer. During the reaction, deuterated methanol liquid is obtained by condensation. The deuterated methanol liquid is distilled and purified in a distillation device. The reaction tail gas enters a relaxation gas storage tank, and then is purified by a palladium membrane gas purification device. The purified deuterium gas enters a deuterium gas storage tank for recycling.

[0059] The single-pass conversion rate was measured to be 99.5% in terms of carbon monoxide. The purity of the collected deuterated methanol liquid after distillation could reach 99.8%. The recovery rate of deuterium gas in the purge gas was 98.0%.

[0060] Embodiment 11

[0061] This embodiment provides a method for synthesizing deuterated methanol and recycling tail gas.

[0062] CuO, ZnO and Al2O3 are mixed evenly in a mass ratio of 7:2:1 to obtain a catalyst. The catalyst and inert alumina ceramic balls are mixed and loaded into a synthesis device in a mass ratio of 2:1 to form a catalyst layer. Deuterium gas and carbon monoxide are prepared into a mixed gas in a molar ratio of 20:1. The mixed gas enters the synthesis device at a speed of 100L / min under a pressure of 4.5MPa. The temperature of the synthesis device is controlled at 275±5℃, and the reaction is continuously circulated for 24 hours under the catalysis of the catalyst layer. During the reaction, deuterated methanol liquid is obtained by condensation. The deuterated methanol liquid is distilled and purified in a distillation device. The reaction tail gas enters a relaxation gas storage tank, and then is purified by a palladium membrane gas purification device. The purified deuterium gas enters a deuterium gas storage tank for recycling.

[0063] The single-pass conversion rate was measured to be 99.8% in terms of carbon monoxide. The purity of the collected deuterated methanol liquid after distillation could reach 99.7%. The deuterium recovery rate in the purge gas was 98.2%.

[0064] Example 12

[0065] This embodiment provides a method for synthesizing deuterated methanol and recycling tail gas.

[0066] CuO, ZnO and Al2O3 are mixed evenly in a mass ratio of 7:2:1 to obtain a catalyst. The catalyst and inert alumina ceramic balls are mixed and loaded into a synthesis device in a mass ratio of 2:1 to form a catalyst layer. Deuterium gas and carbon monoxide are prepared into a mixed gas in a molar ratio of 20:1. The mixed gas enters the synthesis device at a speed of 100L / min under a pressure of 6MPa. The temperature of the synthesis device is controlled at 275±5℃, and the reaction is continuously circulated for 30 days under the catalysis of the catalyst layer. During the reaction, deuterated methanol liquid is obtained by condensation. The deuterated methanol liquid is distilled and purified in a distillation device. The reaction tail gas enters the relaxation gas storage tank, and then is purified by a palladium membrane gas purification device. The purified deuterium gas enters the deuterium gas storage tank for recycling.

[0067] The single-pass conversion rate was measured to be 99.9% in terms of carbon monoxide. The purity of the collected deuterated methanol liquid after distillation could reach 99.8%. The recovery rate of deuterium gas in the purge gas was 98.0%.

[0068] Example 13

[0069] This embodiment is the same as embodiment 12, except that in this embodiment, the ratio of catalyst to inert alumina ceramic ball is 1:2; the speed of introducing mixed gas is 20L / min. The single-pass conversion rate is 99.0% in terms of carbon monoxide, the purity of the collected deuterated methanol liquid after distillation can reach 99.9%, and the recovery rate of deuterium gas in the purge gas is 98.5%.

[0070] Embodiment 14

[0071] This embodiment is the same as embodiment 12, except that in this embodiment, the ratio of catalyst to inert alumina ceramic ball is 1:2; the speed of introducing mixed gas is 200L / min. The single-pass conversion rate is 98.8% in terms of carbon monoxide, the purity of the collected deuterated methanol liquid can reach 99.8% after distillation, and the recovery rate of deuterium gas in the purge gas is 98.5%.

[0072] Embodiment 15

[0073] This embodiment is the same as embodiment 12, except that the continuous cycle reaction time is 7 days. The single-pass conversion rate is 99.5% in terms of carbon monoxide, the purity of the collected deuterated methanol liquid after distillation can reach 99.8%, and the deuterium recovery rate in the purge gas is 98.8%.

[0074] Example 16

[0075] This embodiment is the same as embodiment 12, except that the continuous cycle reaction time is 30 days. The single-pass conversion rate is 99.7% in terms of carbon monoxide, the purity of the collected deuterated methanol liquid after distillation can reach 99.8%, and the deuterium recovery rate in the purge gas is 98.9%.

[0076] The embodiments described above are part of the embodiments of the present invention, but not all of them. The detailed description of the embodiments of the present invention is not intended to limit the scope of the invention claimed for protection, but only represents selected embodiments of the present invention. All other embodiments obtained without creative work and related deductions and substitutions made by ordinary technicians in the field under the conditions of the concept of the present invention belong to the scope of protection of the present invention.

Claims

1. A method for preparing deuterated methanol and recycling tail gas, characterized in that: include: Deuterium gas and carbon monoxide are reacted under temperature, pressure and catalyst conditions to generate deuterated methanol; at the same time, the tail gas generated by the reaction is purified to obtain purified deuterium gas; the purified deuterium gas enters the deuterium gas storage tank and participates in the preparation of deuterated methanol again; The mass ratio of deuterium gas to carbon monoxide is 2.5 to 20:1; The catalyst is a mixture of copper oxide, zinc oxide and aluminum oxide.

2. The method for preparing deuterated methanol and recycling tail gas according to claim 1, characterized in that: The temperature is 200-280°C.

3. The method for preparing deuterated methanol and recycling tail gas according to claim 1, characterized in that: The pressure is 3-6 MPa.

4. The method for preparing deuterated methanol and recycling tail gas according to claim 1, characterized in that: The mass ratio of the copper oxide, zinc oxide and aluminum oxide is 6-7:2-3:

1.

5. The method for preparing deuterated methanol and recycling tail gas according to claim 1, characterized in that: The catalyst is mixed with alumina ceramic balls and filled into a synthesis device to form a catalyst layer.

6. The method for preparing deuterated methanol and recycling tail gas according to claim 5, characterized in that: The mass ratio of the catalyst to the alumina ceramic ball is 1-2:1-2.

7. The method for preparing deuterated methanol and recycling tail gas according to claim 1, characterized in that: The flow rate of the mixed gas of deuterium gas and carbon monoxide is 20 to 200 L / min.

8. The method for preparing deuterated methanol and recycling tail gas according to claim 1, characterized in that: The tail gas was purified by passing it through a palladium membrane.

9. The method for preparing deuterated methanol and recycling tail gas according to claim 1, characterized in that: The reaction time for generating deuterated methanol is 1 to 30 days.

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