Filtering device for 3, 4-dihydroxybenzonitrile
Through a filter device coated with titanium filter element with polytetrafluoroethylene film, the problem of difficult to control color and turbidity in 3,4-dihydroxybenzonitrile purification is solved, and a high-efficiency and low-cost filtration effect is achieved to obtain high-purity products.
Patent Information
- Application Number
- CN202422491045.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-15
- Publication Date
- 2025-09-02
- Estimated Expiration
- 2034-10-15
AI Technical Summary
In the prior art, the purification process of 3,4-dihydroxybenzonitrile is complicated, and the color and turbidity of the product are difficult to meet the requirements, resulting in low yield and purity, which cannot meet the application needs in the fields of drugs and other fields.
The titanium filter element filter device is coated with polytetrafluoroethylene film, combined with a precision filter, a sewage outlet is designed in the center of the bottom, a heating sleeve is set, and the titanium filter element is protected by polytetrafluoroethylene film, which is easy to clean and ensures filtration efficiency and product purity.
Highly efficient decolorization and reduced turbidity are achieved, and a high-purity 3,4-dihydroxybenzonitrile solution is obtained, which improves the yield and purity of the product and reduces the filtration cost.
Smart Images
Figure CN223287753U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of filtering devices, in particular to a filtering device for 3,4-dihydroxybenzonitrile. Background Art
[0002] Color refers to the degree to which dissolved substances or suspended particles in a liquid absorb and scatter light, resulting in the liquid's specific color. Turbidity describes the number and size of suspended particles in a liquid. When suspended particles are present, they scatter light, rendering the water opaque. Generally speaking, the lower the color and turbidity of the product solution before crystallization, the higher the purity of the crystallized product. Color, turbidity, and purity influence the subsequent application of chemical products and are important parameters in R&D and production.
[0003] 3,4-Dihydroxybenzonitrile is an important pharmaceutical and pesticide intermediate, widely used in the pesticide, pharmaceutical, and dye industries. It is primarily used to synthesize drugs containing thiazole, 2-oxazoline, imidazole, triazole, and benzopyrimidine structures, such as the anticancer quinazoline drug. In recent years, 3,4-dihydroxybenzonitrile has also been used in the synthesis of photosensitive materials.
[0004] Currently, there are six main synthetic routes for the synthesis of 3,4-dihydroxybenzonitrile, depending on the starting materials used. However, there is a lack of suitable purification processes. In the existing technology, after synthesizing a crude 3,4-dihydroxybenzonitrile solution using materials such as hydroxylamine hydrochloride, methanol, vanillin, and powdered activated carbon, common operations such as filter pressing and recrystallization are used to achieve decolorization. The purification process is cumbersome, the product loss is large, and the color and turbidity are difficult to meet the requirements. As a result, the yield and purity of the final product cannot meet the requirements.
[0005] Therefore, there is an urgent need to develop a new type of filtration device specifically for the synthesis of 3,4-dihydroxybenzonitrile to reduce the color and turbidity of the product and improve the purity and yield to meet the needs of the application of 3,4-dihydroxybenzonitrile in the fields of medicine and so on. Utility Model Content
[0006] To solve the above problems, the utility model discloses a 3,4-dihydroxybenzonitrile filtering device. The 3,4-dihydroxybenzonitrile filtering device described in the utility model is suitable for synthesizing a crude 3,4-dihydroxybenzonitrile solution using materials such as hydroxylamine hydrochloride, methanol, vanillin, and powdered activated carbon, and then using a precision filter to perform decolorization filtration with high requirements for turbidity and color, thereby obtaining a 3,4-dihydroxybenzonitrile solution with high requirements for color and turbidity, and crystallizing to obtain a high-purity 3,4-dihydroxybenzonitrile product.
[0007] To achieve the above objectives, the present invention provides the following technical solutions:
[0008] On the one hand, the utility model provides a filtering device for 3,4-dihydroxybenzonitrile, comprising a heating kettle, a filter press, a receiving kettle and a precision filter. The heating kettle, the filter press, the receiving kettle and the precision filter are connected in sequence by pipes. An upper core plate is fixedly arranged at the upper end of the precision filter, and a lower core plate is fixedly arranged at the lower end. The upper core plate and the lower core plate are fixed by a fixing rod. One or more filter cores are fixed between the upper core plate and the lower core plate, and the filter core is a titanium filter core coated with a polytetrafluoroethylene membrane.
[0009] Titanium filter elements are porous titanium filter elements made from industrial high-purity titanium powder (99.6%, 0.4% titanium alloy: nitrogen, hydrogen, iron, manganese, etc.). They are screened, cold isostatically pressed, and then sintered at high temperature and high vacuum. Titanium filter elements offer high separation and permeation efficiencies, but they cannot be directly used for filtering 3,4-dihydroxybenzonitrile. This is because titanium filter elements are easily corroded by crude 3,4-dihydroxybenzonitrile solutions, are difficult to clean, and cannot be reused.
[0010] The characteristics of polytetrafluoroethylene (PTFE) membranes include their unique fibrillar microporous structure and a porosity exceeding 85%. Each square centimeter of the membrane contains approximately 1.4 billion micropores with uniform pore size, high permeability, and excellent corrosion resistance.
[0011] The polytetrafluoroethylene membrane-coated titanium filter element is a special device specially designed for 3,4-dihydroxybenzonitrile in the utility model: a layer of polytetrafluoroethylene membrane is coated on the surface of the titanium filter element, which has strong permeability and does not affect the filtering performance of the titanium filter element; it can protect the porous structure of the titanium filter element and effectively prevent the titanium filter element from being corroded; at the same time, it is easy to clean, so that the titanium filter element can be reused, thereby improving the filtration efficiency and reducing the filtration cost.
[0012] Titanium filter elements and polytetrafluoroethylene membrane coating processes are both highly commercialized products and processes. Any homemade or commercially available polytetrafluoroethylene membrane-coated titanium filter element can be used in the present invention to achieve the same technical effects as the present invention.
[0013] In some embodiments, the polytetrafluoroethylene film has a thickness of 5 μm-5 mm.
[0014] In some embodiments, the pore size of the polytetrafluoroethylene membrane is 0.02-5 μm.
[0015] Preferably, the pore size of the polytetrafluoroethylene membrane is 0.1 μm.
[0016] In some embodiments, the precision filter further includes a feed port, a discharge port and a sewage outlet, the height of the discharge port is higher than the height of the feed port, the height of the sewage outlet is lower than the height of the feed port, and the feed port, discharge port and sewage outlet are respectively matched with a feed control valve, a discharge control valve and a sewage control valve.
[0017] In some embodiments, the feed port is located at the middle height of the precision filter, the discharge port is located at a higher middle position of the precision filter, and the sewage outlet is located at the bottom of the precision filter.
[0018] In some embodiments, the drain port is disposed at the bottom center of the precision filter.
[0019] The sewage outlet is set at the bottom center of the precision filter so that the liquid in the bottom center of the precision filter can be discharged in time. The bottom center is usually the area where solid impurities are most likely to deposit. Discharging sewage here is beneficial to improving filtration efficiency and product purity.
[0020] In some embodiments, a switch control valve is provided at the top of the precision filter for adding water, and a drain control valve is provided at the bottom for draining water.
[0021] Because the titanium filter element coated with polytetrafluoroethylene membrane is easy to clean, after the filtration is completed, the switch control valve can be opened and the filter element can be rinsed downward with water to clean it for the next filtration.
[0022] In some embodiments, heating jackets are provided outside the heating kettle and the receiving kettle.
[0023] In some embodiments, the pipe connecting the heating kettle and the filter press is made of PP material.
[0024] In some embodiments, the pipe connecting the filter press and the receiving kettle is made of 304 stainless steel.
[0025] In some embodiments, the pipe connecting the receiving kettle and the precision filter is made of PP material.
[0026] In some embodiments, the inner wall material of the precision filter is enamel.
[0027] In some embodiments, the filter press is a plate and frame filter press.
[0028] In some embodiments, a bracket is provided at the bottom of the precision filter for fixing.
[0029] The beneficial technical effects of the utility model are:
[0030] 1. The utility model provides a new filtration device for 3,4-dihydroxybenzonitrile, which can perform decolorization filtration with high requirements for turbidity and color, thereby obtaining a 3,4-dihydroxybenzonitrile solution with high requirements for color and turbidity, and crystallizing to obtain a high-purity 3,4-dihydroxybenzonitrile product.
[0031] 2. A layer of polytetrafluoroethylene membrane is coated on the surface of the titanium filter element, which has strong permeability and does not affect the filtering performance of the titanium filter element; it can protect the porous structure of the titanium filter element and effectively prevent the titanium filter element from being corroded; at the same time, it is easy to clean, so that the titanium filter element can be reused, improving the filtering efficiency while reducing the filtering cost.
[0032] 3. As the filtration progresses, solid impurities are gradually removed from the filter element and deposited downward under the action of gravity. Therefore, the purity of 3,4-dihydroxybenzonitrile increases with increasing height. The height of the discharge port is higher than that of the feed port, which enables timely collection of high-purity products. The height of the sewage outlet is lower than that of the feed port, which enables timely discharge of impurities to avoid contamination of the product above, thereby improving the purity of the final product.
[0033] 4. The sewage outlet is set at the bottom center of the precision filter so that the liquid in the bottom center of the precision filter can be discharged in time. The bottom center is usually the area where solid impurities are most likely to deposit. Discharging sewage here is beneficial to improving filtration efficiency and product purity.
[0034] 5. Set up a heating jacket to keep the temperature of the liquid being filtered within a certain range to avoid the increase in viscosity at low temperatures affecting filtration; select suitable inner wall materials for the liquid at different stages of the filtration process to withstand the fluid pressure during filtration, avoid corrosion of the filter device, prevent solid impurities from adhering to the inner wall, and facilitate cleaning. BRIEF DESCRIPTION OF THE DRAWINGS
[0035] Figure 1 This is a schematic structural diagram of a filtration device for 3,4-dihydroxybenzonitrile of the present invention;
[0036] Figure 2 This is a cross-sectional view of the titanium filter element coated with polytetrafluoroethylene membrane of the present invention;
[0037] Among them, the figures are marked as: heating kettle 1, first control valve 11, first heating jacket 12, descending stirring paddle 13, first drain pipe 14, first drain valve 15, first pipeline 2, plate filter press 3, second pipeline 4, receiving kettle 5, second control valve 51, second heating jacket 52, second drain pipe 53, second drain valve 54, third pipeline 6, feed control valve 61, precision filter 7, feed port 71, discharge port 72, discharge control valve 73, drain port 74, drain control valve 75, drain collection port 76, upper core plate 77, lower core plate 78, fixing rod 79, filter element 710, polytetrafluoroethylene membrane 7101, titanium filter element 7102, switch control valve 711, water supply pipeline 712, drain control valve 713, drain port 714, bracket 715. DETAILED DESCRIPTION
[0038] The present invention will be further described below in conjunction with the accompanying drawings and embodiments. Identical components are denoted by the same reference numerals. It should be noted that the terms "front," "rear," "left," "right," "upper," and "lower" used in the following description refer to directions in the accompanying drawings, and the terms "bottom," "top," "inner," and "outer" refer to directions toward or away from the geometric center of a particular component, respectively.
[0039] like Figure 1 The filtration device for 3,4-dihydroxybenzonitrile shown in the figure is as follows: before filtration, the first control valve 11 is opened to add the crude 3,4-dihydroxybenzonitrile solution to be filtered into the heating kettle 2; a descending stirring paddle 13 is provided in the heating kettle 2 to ensure the uniformity of the product before filtration; a first drain pipe 14 and a first drain valve 15 are provided at the bottom of the heating kettle 2; when the first drain valve 15 is opened, the waste is discharged downward from the first drain pipe 14; a first heating jacket 12 is provided outside the heating kettle 2 to ensure that the temperature in the kettle is always maintained at the required temperature; the top of the heating kettle 2 is connected to the first pipe 2 by a flange; a pump is provided in the pipe path; and the liquid in the heating kettle 2 is pumped into the plate filter press 3 via the pump.
[0040] The plate filter press 3 can perform preliminary filtration on the crude 3,4-dihydroxybenzonitrile solution. The second control valve 51 provided on the receiving kettle 5 is opened, and the liquid filtered by the plate filter press 3 flows into the receiving kettle 5 through the second pipe 4 under the action of the pump.
[0041] A second heating jacket 52 is provided on the outside of the receiving kettle 5. A second drain pipe 53 and a second drain valve 54 are provided at the bottom of the receiving kettle 5 for discharging waste. When the second drain valve 54 is opened, the waste is discharged downward from the second drain pipe 53. The receiving kettle 5 is connected to the precision filter 7 through the third pipe 6. A third control valve 61 is provided on the third pipe 6. When the third control valve 61 is opened, the liquid in the receiving kettle 5 is pumped into the precision filter 7 through the third pipe 6 and the feed port 71 in sequence under the pressure of the pump.
[0042] Two brackets 715 are provided at the bottom of the precision filter 7 to support the precision filter 7. An upper core plate 77 is fixed horizontally at the upper position of the precision filter 7, and a lower core plate 78 is fixed horizontally at the lower position. The upper core plate 77 and the lower core plate 78 are connected to the inner wall of the precision filter 7 for fixation. A fixing rod 79 is also connected between the upper core plate 77 and the lower core plate 78 to further fix them to each other. The upper core plate 77, the lower core plate 78 and the fixing rod 79 only have a fixing function and will not hinder the flow of liquid.
[0043] Two filter elements 710 are fixed between the upper core plate 77 and the lower core plate 78. The filter element 710 is a titanium filter element coated with a polytetrafluoroethylene membrane. Figure 2As shown, the interior of the filter element 710 is a titanium filter element 7102, the surface of which is evenly coated with a polytetrafluoroethylene membrane 7101. The thickness of the polytetrafluoroethylene membrane 7101 is 10 μm, and the pore size of the polytetrafluoroethylene membrane 7101 is 0.1 μm. The liquid is continuously filtered inside the precision filter 7 under the action of the filter element 710. The filtration is mainly achieved by the adsorption of solid impurity particles by the polytetrafluoroethylene membrane 7101 and the titanium filter element 7102.
[0044] The precision filter 7 has a feed port 71, a discharge port 72 and a sewage outlet 74 according to the feeding, discharging and sewage discharge of the material, which are switched and flow-controlled by the feed control valve 61, the discharge control valve 73 and the sewage discharge control valve 75 respectively; the feed port 71 is located in the middle of the precision filter 7, the discharge port 72 is located in the upper middle of the precision filter 7, and the sewage outlet 74 is located in the bottom center of the precision filter 7. After the sewage discharge control valve 75 is opened, the liquid carrying a large amount of solid impurities in the bottom center of the precision filter 7 is discharged in time from the sewage collection port 76.
[0045] After the filtration operation is performed according to the above steps, the discharge control valve 72 is opened, and samples are collected and tested. After high performance liquid chromatography, the purity is ≥99.5%, the colorimeter is tested, the color is ≤250 APHA, and the turbidity is tested by a turbidity meter, and the turbidity is ≤5 NTU. The purity, color, and turbidity indicators are all qualified. At this time, the filtered product is subjected to the next step of crystallization to obtain the final product.
[0046] A switch control valve 711 is provided at the top of the precision filter 7 for adding water, and a drain control valve 713 is provided at the bottom for draining water. After the filtration is completed, the switch control valve 711 and the drain control valve 713 are opened at the same time, and water is input into the precision filter 7 from the water supply pipe 712, rinses the filter element 710 downward and carries solid impurities out from the drain port 714. The rinsing is continued for a period of time to ensure that the filter element 710 is cleaned so that the next round of filtration operation can be carried out.
[0047] The inner wall material of the heating kettle 1 is enamel; the first pipe 2 is made of PP; the second pipe 4 is made of 304 stainless steel; the inner wall material of the receiving kettle 5 is enamel; the third pipe 6 is made of PP; the inner wall material of the precision filter 7 is enamel.
[0048] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiment. All technical solutions based on the concept of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, certain improvements and modifications that do not depart from the principles of the present invention should also be considered within the scope of protection of the present invention.
Claims
1. A filtering device for 3,4-dihydroxybenzonitrile, characterized in that: It includes a heating kettle, a filter press, a receiving kettle and a precision filter. The heating kettle, the filter press, the receiving kettle and the precision filter are connected by pipes in sequence. An upper core plate is fixed at the upper end of the precision filter, and a lower core plate is fixed at the lower end. The upper core plate and the lower core plate are fixed with a fixing rod. One or more filter elements are fixed between the upper core plate and the lower core plate. The filter element is a titanium filter element coated with a polytetrafluoroethylene membrane.
2. The filtering device for 3,4-dihydroxybenzonitrile according to claim 1, characterized in that: The pore size of the polytetrafluoroethylene membrane is 0.02-5 μm.
3. The filtering device for 3,4-dihydroxybenzonitrile according to claim 1, characterized in that: The precision filter also includes a feed port, a discharge port and a sewage outlet. The height of the discharge port is higher than that of the feed port, and the height of the sewage outlet is lower than that of the feed port. The feed port, discharge port and sewage outlet are respectively matched with a feed control valve, a discharge control valve and a sewage control valve.
4. The filtering device for 3,4-dihydroxybenzonitrile according to claim 3, characterized in that: The sewage outlet is arranged at the bottom center of the precision filter.
5. The filtering device for 3,4-dihydroxybenzonitrile according to claim 1, characterized in that: The top of the precision filter is provided with a switch control valve for adding water, and the bottom is provided with a drain control valve for draining water.
6. The filtering device for 3,4-dihydroxybenzonitrile according to claim 1, characterized in that: The outsides of the heating kettle and the receiving kettle are provided with heating jackets.
7. The filtering device for 3,4-dihydroxybenzonitrile according to claim 1, characterized in that: The inner wall materials of the heating kettle and the receiving kettle are enamel.
8. The filtering device for 3,4-dihydroxybenzonitrile according to claim 1, characterized in that: The pipe connecting the heating kettle and the filter press is made of PP material.
9. The filtering device for 3,4-dihydroxybenzonitrile according to claim 1, characterized in that: The pipe connecting the filter press and the product receiving kettle is made of 304 stainless steel.
10. The filtering device for 3,4-dihydroxybenzonitrile according to claim 1, characterized in that: The filter press is a plate and frame filter press.