Dimethyl sulfoxide preparation process and reactor

Abstract

The invention discloses a dimethyl sulfoxide preparation process and a reactor. The dimethyl sulfoxide preparation process comprises the following steps: adding methanol and sulfuric acid into the reactor; monitoring the concentration of waste gas in the reactor in the reaction process; a catalyst is added to the reactor according to the exhaust gas concentration. The reaction temperature of the methanol and the sulfuric acid is 50-70 DEG C. When a detector detects that the concentration of sulfur dioxide is too high, the reaction is proved to be incomplete, and a catalyst is added into the reactor, so that methanol and sulfuric acid can fully react, and the generation amount of sulfur dioxide waste gas is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of dimethyl sulfoxide preparation, and in particular to a dimethyl sulfoxide preparation process and a reactor. Background Art

[0002] The preparation methods of dimethyl sulfoxide generally include: dimethyl sulfate method, dimethyl sulfide method, and hydrogen peroxide oxidation method. The dimethyl sulfate method is to mix methanol and sulfuric acid, and react them under the action of a catalyst to generate dimethyl sulfate; react dimethyl sulfate with sodium sulfite to generate sodium dimethyl sulfinate and sodium sulfate; react sodium dimethyl sulfinate with sodium hydroxide to generate dimethyl sulfoxide and sodium sulfite.

[0003] The advantages of this method are that the raw materials are easily available, the reaction conditions are mild, and the yield is high. However, a large amount of waste water and waste gas will be generated during the production process, causing certain pollution to the environment. The reason is that the reaction of methanol and sulfuric acid in the reactor is not complete. Therefore, the present invention proposes a dimethyl sulfoxide preparation process and a reactor. Summary of the invention

[0004] In view of the problem of generating a large amount of exhaust gas in the above-mentioned prior art, the present invention is proposed.

[0005] Therefore, the present invention aims to provide a process for preparing dimethyl sulfoxide.

[0006] To solve the above technical problems, the present invention provides the following technical solutions: a process for preparing dimethyl sulfoxide, comprising adding methanol and sulfuric acid into a reactor; monitoring the exhaust gas concentration in the reactor during the reaction; and adding a catalyst into the reactor according to the exhaust gas concentration.

[0007] As the dimethyl sulfoxide preparation process of the present invention, wherein: the reaction temperature of the methanol and sulfuric acid is 50-70°C.

[0008] As the dimethyl sulfoxide preparation process of the present invention, wherein: the catalyst is a solid acid catalyst.

[0009] As the dimethyl sulfoxide preparation process of the present invention, wherein: the catalyst is γ-alumina.

[0010] The present invention also proposes a reactor used in the above-mentioned dimethyl sulfoxide preparation process, including a body, which includes a tank body; a temperature control mechanism, which is arranged on the tank body and is used to control the temperature inside the tank body; an exhaust gas monitoring mechanism, which is arranged on the tank body and is used to monitor the exhaust gas concentration inside the tank body; a delivery mechanism, including a storage tank arranged on the tank body, a dosing device connected to the storage tank, a delivery port arranged on the dosing device, and a baffle capable of closing the delivery port.

[0011] As a preferred embodiment of the reactor described in the present invention, it also includes an opening and closing mechanism; it includes a bottom tank, which is connected to the doser; a moving part, which is movably arranged inside the bottom tank; an extension tube, which is installed on the moving part and one end of which extends to the inner side of the doser; a plugging head, which is installed at one end of the extension tube located on the inner side of the doser; the plugging head can seal the connection between the storage tank and the doser.

[0012] As a preferred embodiment of the reactor described in the present invention, the movable member divides the interior of the bottom cabin into two chambers, one of which is an upper cavity and the other is a lower cavity; an air inlet is provided on the side wall of the upper cavity of the bottom cabin, and an extraction port and a switch port are provided on the lower cavity of the bottom cabin; an elastic member is also provided between the movable member and the bottom cabin, and the elastic member resists the movable member in the direction of the doser.

[0013] As a preferred embodiment of the reactor described in the present invention, an adsorption channel connected to the upper cavity is opened at the bottom of the storage tank, and a sealing plug is arranged at the opening of the adsorption channel on the baffle plate; the reactor also includes a tightening mechanism, and the tightening mechanism includes an air cabin, one end of which is connected to the adsorption channel, and the other end is connected to the upper cavity; an extended blocking rod, one end of which is located inside the air cabin, and the other end extends to the inside of the upper cavity to connect with the moving part.

[0014] As a preferred solution of the reactor of the present invention, a positioning ring is arranged inside the gas chamber, and the extended blocking rod comprises a rod body slidably connected to the positioning ring, and a sealing head affixed to the inner wall of the gas chamber.

[0015] As a preferred embodiment of the reactor of the present invention, the end of the extension tube located inside the bottom tank is provided with a bottom opening, and the end of the extension tube located inside the doser is provided with a diffusion opening.

[0016] The beneficial effect of the present invention is that when the detector detects that the concentration of sulfur dioxide is too high, it proves that the reaction is incomplete. By adding a catalyst into the reactor, methanol and sulfuric acid can fully react, thereby reducing the amount of sulfur dioxide waste gas generated. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0018] Figure 1 It is a schematic diagram of the overall structure of the reactor of the present invention.

[0019] Figure 2 It is a schematic diagram of the internal structure of the can body described in the present invention.

[0020] Figure 3 It is a schematic diagram of the structure of the delivery mechanism described in the present invention.

[0021] Figure 4 It is a schematic diagram of the internal structure of the delivery mechanism described in the present invention.

[0022] Figure 5 It is a schematic diagram of the bottom cabin structure described in the present invention.

[0023] Figure 6 It is a structural schematic diagram of the tightening mechanism described in the present invention.

[0024] Figure 7 For the present invention Figure 6 Enlarged view of point A in the middle. DETAILED DESCRIPTION

[0025] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0026] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0027] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor is it a separate or selective embodiment that is mutually exclusive with other embodiments.

[0028] Secondly, the present invention is described in detail with reference to the schematic diagram. When describing the embodiments of the present invention in detail, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0029] Example 1

[0030] The present embodiment provides a process for preparing dimethyl sulfoxide, comprising adding methanol and sulfuric acid into a reactor; monitoring the exhaust gas concentration in the reactor during the reaction; adding a catalyst into the reactor according to the exhaust gas concentration, wherein methanol and sulfuric acid react to generate dimethyl sulfate. During the reaction of methanol and sulfuric acid inside the reactor, exhaust gas is generated, wherein the main component of the exhaust gas is sulfur dioxide. When monitoring the sulfur dioxide concentration inside the reactor, a sulfur dioxide concentration detector is used. When the detector detects that the sulfur dioxide concentration is too high, it indicates that the reaction is incomplete. By adding a catalyst into the reactor, methanol and sulfuric acid can fully react, thereby reducing the generation of sulfur dioxide exhaust gas.

[0031] Methanol reacts with sulfuric acid to generate dimethyl sulfate, the obtained dimethyl sulfate is mixed with sodium sulfite and put into a reactor for reaction to obtain sodium dimethyl sulfinate, the obtained sodium dimethyl sulfinate is mixed with sodium hydroxide and put into a reactor for reaction to finally obtain dimethyl sulfoxide.

[0032] In each reaction process, the corresponding waste gas detector can be used according to the type of waste gas that may be generated to reduce the amount of waste gas generated in each reaction process.

[0033] Specifically, the reaction temperature of methanol and sulfuric acid is 50-70° C., and the reaction time is 2 to 4 hours.

[0034] The reaction temperature of dimethyl sulfate and sodium sulfite is 40-60° C., and the reaction time is 1 to 3 hours.

[0035] The reaction temperature of sodium dimethylsulfinate and sodium hydroxide is 60-80°C, and the reaction time is 2 to 4 hours.

[0036] Furthermore, the catalyst is a solid acid catalyst.

[0037] Furthermore, the catalyst is γ-alumina.

[0038] Example 2

[0039] Reference Figure 1 - Figure 3 This embodiment is different from the first embodiment in that: this embodiment proposes a reactor applied to the dimethyl sulfoxide preparation process in the above embodiment, including a body 100, which includes a tank body 101; wherein the body 100 also includes a bracket 102, the tank body 101 is installed on the bracket 102, the bracket 102 forms an effective support for the tank body 101, and the interior of the tank body 101 is a reaction space.

[0040] The reactor includes a temperature control mechanism 200, which is arranged on the tank body 101 for controlling the temperature inside the tank body 101. The temperature control mechanism is a heating structure that can heat the environment and reaction materials inside the tank body 101, so that the reaction materials can react at a suitable temperature and reduce the amount of waste gas generated.

[0041] The reactor includes a waste gas monitoring mechanism 300, which is arranged on the tank body 101 to monitor the waste gas concentration inside the tank body 101. The waste gas monitoring mechanism 300 uses an industrial waste gas detector, and the specific type is determined according to the type of waste gas that may be generated by the reaction. For example, when methanol and sulfuric acid react, a sulfur dioxide detector is used.

[0042] The reactor includes a delivery mechanism 400 , including a storage tank 401 disposed on the tank body 101 , a dosing device 402 connected to the storage tank 401 , a delivery port 403 disposed on the dosing device 402 , and a baffle 404 capable of closing the delivery port 403 .

[0043] The catalyst is loaded and stored inside the storage tank 401. When the exhaust gas monitoring mechanism 300 detects that the exhaust gas content exceeds the standard, the catalyst inside the storage tank 401 enters the interior of the doser 402. After a certain amount of catalyst enters the interior of the doser 402, the baffle 404 unfolds, and the catalyst enters the inside of the tank body 101 from the injection port 403 and contacts the reactants, thereby reducing the by-products generated during the reaction process and thus reducing the amount of exhaust gas generated.

[0044] There are multiple delivery ports 403 . In this embodiment, there are 6 delivery ports 403 . The 6 delivery ports 403 are arranged in a ring shape on the side walls of the doser 402 . The catalyst can be more dispersedly introduced into the inner side of the storage tank 401 .

[0045] The rest of the structure is the same as that of Example 1.

[0046] Example 3

[0047] Reference Figures 2 to 5 This embodiment is different from the above embodiments in that: the reactor also includes an opening and closing mechanism 500; it includes a bottom cabin 501, which is connected to the doser 402; a moving part 502, which is movably arranged inside the bottom cabin 501; an extension tube 503, which is installed on the moving part 502, and one end of which extends to the inner side of the doser 402; a plugging head 504, which is installed at one end of the extension tube 503 located on the inner side of the doser 402; the plugging head 504 can plug the connection between the storage tank 401 and the doser 402.

[0048] The movable part 502 can move inside the bottom cabin 501, and the direction of its movement is close to or away from the doser 402. During this process, the movable part 502 can drive the extension tube 503 to move, and the moving extension tube 503 can drive the blocking head 504 to move. When the movable part 502 is close to the doser 402, the blocking head 504 can block the connection between the storage tank 401 and the doser 402. At this time, the catalyst inside the storage tank 401 cannot enter the inner side of the doser 402. When the movable part 502 is far away from the doser 402, the blocking head 504 no longer blocks the connection between the storage tank 401 and the doser 402. At this time, the catalyst can enter the inner side of the doser 402.

[0049] Furthermore, the movable part 502 divides the interior of the bottom cabin 501 into two chambers, one of which is the upper chamber N1, and the other is the lower chamber N2; a movable sealing structure, such as a movable sealing ring, is provided on the movable part 502, and the side wall of the movable part 502 is in contact with the inner wall of the bottom cabin 501, so that the upper chamber N1 and the lower chamber N2 are independent of each other, thereby preventing the gases inside the upper chamber N1 and the lower chamber N2 from communicating with each other.

[0050] The bottom cabin 501 is provided with an air inlet 501a on the side wall of the upper cavity N1. The air inlet 501a may be provided with a one-way valve, and gas may enter the inner side of the upper cavity N1 through the air inlet 501a.

[0051] The bottom cabin 501 is provided with an extraction port 501b and a switch port 501c in the lower cavity N2; wherein the extraction port 501b is connected to an external air pump, which can extract the gas inside the lower cavity N2; a switch is installed at the switch port 501c, which is preferably a solenoid valve, which can control the switching state of the switch; an elastic member 501d is also provided between the moving member 502 and the bottom cabin 501, and the elastic member 501d resists the moving member 502 in the direction of the doser 402.

[0052] When it is monitored that the exhaust gas concentration exceeds the standard, the air pump starts working. At this time, the switch port 501c is in a closed state, and the gas inside the lower cavity N2 is extracted. At the same time, the external gas enters the inner side of the upper cavity N1 through the air inlet 501a. At this time, driven by the gas pressure, the moving part 502 moves away from the doser 402. The moving part 502 can drive the extension tube 503 to move, and the blocking head 504 no longer blocks the connection between the doser 402 and the storage tank 401. The catalyst inside the storage tank 401 enters the interior of the doser 402.

[0053] When a certain amount of catalyst enters the storage tank 401, the air pump is turned off and the switch port 501c is switched to an open state, and the external gas can enter the inner side of the lower cavity N2 through the switch port 501c. Driven by the elastic member 501d, the movable member 502 moves toward the doser 402, driving the extension tube 503 to move, so that the sealing head 504 reaches the connection between the doser 402 and the storage tank 401, so that the storage tank 401 and the doser 402 are no longer connected.

[0054] The rest of the structure is the same as that of Example 2.

[0055] Example 4

[0056] Reference Figures 2 to 7 This embodiment is different from the above embodiments in that: in order to keep the baffle 404 in a stable closed state during the process of loading the catalyst into the doser 402, an adsorption channel 401a connected to the upper cavity N1 is opened at the bottom of the storage tank 401, and a sealing plug 404a is provided at the opening of the baffle 404 and the adsorption channel 401a; the reactor also includes a tightening mechanism 600, and the tightening mechanism 600 includes an air chamber 601, one end of which is connected to the adsorption channel 401a, and the other end is connected to the upper cavity N1; an extended blocking rod 602, one end of which is located inside the air chamber 601, and the other end extends to the inside of the upper cavity N1 to connect with the moving part 502.

[0057] The top of the baffle 404 is rotatably connected to the outer wall of the doser 402 through a rotating shaft. In a natural state, the baffle 404 is vertically downward due to the influence of gravity, and the sealing plug 404a is at the opening of the adsorption channel 401a. When the movable part 502 moves downward, the catalyst enters the inner side of the doser 402. During this process, the movable part 502 drives the extension tube 503 to move downward, and drives the extension blocking rod 602 to move. During this process, the air pressure in the partial space connecting the air cabin 601 and the adsorption channel 401a decreases rapidly, and the external air pressure will push the baffle 404, so that the sealing plug 404a is pressed against the opening of the adsorption channel 401a, making the baffle 404 unable to unfold. Therefore, when the catalyst enters the interior of the doser 402, it cannot push the baffle 404 to unfold, so that the baffle 404 remains in a closed state.

[0058] When the switch port 501c is converted to the open state, a large amount of external gas enters into the lower cavity N2 through the switch port 501c, and the elastic member 501d pushes the movable member 502 to move toward the doser 402. At the same time, the extended blocking rod 602 moves synchronously, so that the air pressure in the partial space connecting the air chamber 601 and the adsorption channel 401a increases rapidly, so that the baffle 404 is no longer positioned, and the gas inside the doser 402 can push open the baffle 404 and enter into the tank body 101 from the delivery port 403.

[0059] Therefore, the tightening mechanism 600 has two functions:

[0060] The first is that the baffle 404 can be closed when the catalyst inside the storage tank 401 enters the inside of the dosing device 402 .

[0061] The second is that when the movable part 502 moves upward, because the air pressure in the partial space connecting the air cabin 601 and the adsorption channel 401a is very small, it can quickly attract the extended blocking rod 602 to move and apply a pulling force to the movable part 502, thereby helping the movable part 502 to quickly reset, thereby quickly closing the connection between the storage tank 401 and the doser 402.

[0062] Specifically, a positioning ring 601 a is provided inside the air chamber 601 , and the extended blocking rod 602 includes a rod body 602 a slidably connected to the positioning ring 601 a , and a sealing head 602 b fitted to the inner wall of the air chamber 601 .

[0063] Under the limitation of the positioning ring 601a, the rod body 602a can move inside the air chamber 601, thereby driving the sealing head 602b to move.

[0064] The rest of the structure is the same as that of Example 3.

[0065] Example 5

[0066] Reference Figure 6 This embodiment is different from the above embodiments in that a bottom opening 503a is provided at one end of the extension tube 503 located inside the bottom cabin 501, and a diffusion opening 503b is provided at one end of the extension tube 503 located inside the doser 402, wherein there are multiple diffusion openings 503b distributed in a ring shape on the radial side wall of the extension tube 503.

[0067] In this embodiment, the air inlet 501a is set as a one-way air intake, which can be achieved by a one-way valve. The external gas can enter the inner side of the bottom cabin 501 through the air inlet 501a. Therefore, when the movable part 502 moves downward, the external gas enters the upper cavity N1. When the air pump is turned off and the switch port 501c is converted to an open state, the movable part 502 moves upward to squeeze the gas inside the upper cavity N1. At this time, the gas enters the extension tube 503 through the low port, reaches the diffusion port 503b through the extension tube 503, and is blown out through the diffusion port 503b. The catalyst inside the doser 402 can be blown to the edge of the doser 402 and quickly delivered through the delivery port 403 at the edge.

[0068] Importantly, it should be noted that the construction and arrangement of the present application shown in a plurality of different exemplary embodiments are only exemplary. Although only a few embodiments are described in detail in this disclosure, it should be readily understood by those who refer to this disclosure that many modifications are possible (e.g., the size, scale, structure, shape and proportion of various elements, as well as parameter values ​​(e.g., temperature, pressure, etc.), mounting arrangements, use of materials, color, directional changes, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in the application. For example, the element shown as integrally formed can be composed of multiple parts or elements, the position of the element can be inverted or otherwise changed, and the nature or number or position of the discrete element can be changed or changed. Therefore, all such modifications are intended to be included in the scope of the present invention. The order or sequence of any process or method steps can be changed or reordered according to alternative embodiments. In the claims, any "device plus function" clause is intended to cover the structure described herein that performs the function, and is not only structurally equivalent but also equivalent structure. Without departing from the scope of the present invention, other replacements, improvements, changes and omissions can be made in the design, operating conditions and arrangement of the exemplary embodiments. Therefore, the invention is not limited to a specific embodiment, but extends to several modifications still falling within the scope of the appended claims.

[0069] Additionally, in order to provide a concise description of exemplary embodiments, all features of an actual embodiment (ie, those features that are not relevant to the best mode presently contemplated for carrying out the invention or those that are not relevant to implementing the invention) may not be described.

[0070] It should be understood that in the development of any actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort may be complex and time-consuming, but for those of ordinary skill having the benefit of this disclosure, without undue experimentation, the development effort will be a routine task of design, fabrication, and production.

[0071] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A process for preparing dimethyl sulfoxide, characterized in that: The method comprises adding methanol and sulfuric acid to a reactor; Monitor the exhaust gas concentration in the reactor during the reaction; Catalyst is added to the reactor according to the exhaust gas concentration.

2. The process for preparing dimethyl sulfoxide according to claim 1, wherein: The reaction temperature of the methanol and sulfuric acid is 50-70°C.

3. The process for preparing dimethyl sulfoxide according to claim 1 or 2, characterized in that: The catalyst is a solid acid catalyst.

4. The process for preparing dimethyl sulfoxide according to claim 1 or 2, wherein: The catalyst is gamma-alumina.

5. A reactor used in the process for preparing dimethyl sulfoxide according to any one of claims 1 to 4, characterized in that: include, A vessel body (100), comprising a can body (101); A temperature control mechanism (200) is disposed on the can body (101) and is used to control the temperature inside the can body (101); An exhaust gas monitoring mechanism (300) is disposed on the tank body (101) and is used to monitor the exhaust gas concentration inside the tank body (101); The delivery mechanism (400) comprises a storage tank (401) arranged on the tank body (101), a dosing device (402) connected to the storage tank (401), a delivery port (403) arranged on the dosing device (402), and a baffle (404) capable of closing the delivery port (403).

6. The reactor according to claim 5, characterized in that: Also includes an opening and closing mechanism (500); These include, A bottom tank (501) connected to the dosing device (402); A moving part (502) is movably arranged inside the bottom cabin (501); An extension tube (503) is mounted on the moving member (502), one end of which extends to the inner side of the doser (402); A plugging head (504) is mounted on one end of the extension tube (503) located inside the doser (402); The plugging head (504) can seal the connection between the storage tank (401) and the doser (402).

7. The reactor according to claim 6, characterized in that: The moving part (502) divides the interior of the bottom cabin (501) into two chambers, one of which is an upper chamber (N1) and the other is a lower chamber (N2); The bottom cabin (501) is provided with an air inlet (501a) on the side wall of the upper cavity (N1), and the bottom cabin (501) is provided with an extraction port (501b) and a switch port (501c) on the lower cavity (N2); An elastic member (501d) is also provided between the moving member (502) and the bottom cabin (501), and the elastic member (501d) abuts against the moving member (502) in the direction of the dosing device (402).

8. The reactor according to claim 7, characterized in that: The bottom of the storage tank (401) is provided with an adsorption channel (401a) connected to the upper cavity (N1), and a sealing plug (404a) is provided at the opening of the adsorption channel (401a) on the baffle (404); The reactor further comprises a tightening mechanism (600), wherein the tightening mechanism (600) comprises: An air chamber (601), one end of which is in communication with the adsorption channel (401a), and the other end of which is in communication with the upper cavity (N1); An extended blocking rod (602) has one end located inside the air chamber (601) and the other end extending to the inside of the upper cavity (N1) to be connected to the moving part (502).

9. The reactor according to claim 8, characterized in that: A positioning ring (603) is arranged inside the air chamber (601), and the extended blocking rod (602) comprises a rod body (602a) slidably connected to the positioning ring (601a), and a sealing head (602b) affixed to the inner wall of the air chamber (601).

10. The reactor according to claim 9, characterized in that: The end of the extension tube (503) located inside the bottom tank (501) is provided with a bottom opening (503a), and the end of the extension tube (503) located inside the dosing device (402) is provided with a diffusion opening (503b).

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