Nitrochlorobenzene freezing point detection device and test method

Abstract

The invention discloses a nitrochlorobenzene freezing point detection device and a test method. The device comprises a base, and a test device, a power supply and control module and a freezing module are arranged on the base. A refrigerator is arranged in the freezing module and is used for providing cooling capacity for the test device; the power supply and control module comprises a power supply and a controller; the power supply is used for supplying power to the freezing module and the test device; the test device comprises a fixed table, a lifting driving device, a lifting table, a test container and a bath. The test container comprises a test bottle, a stirrer, a temperature sensor, a torque sensor, a test bottle cap and a dropwise adding meter. The controller judges whether the test sample reaches a freezing point or not according to the torque value of the stirring shaft, when the test sample reaches the freezing point, the controller stores the measured temperature of the temperature sensor, and the temperature is the freezing point temperature of the test sample. The nitrochlorobenzene freezing point detection device can replace manual work to automatically detect the nitrochlorobenzene freezing point, and is high in detection efficiency, high in detection precision and good in repeatability.

Description

Technical Field

[0001] The invention relates to the technical field of chemical detection, and in particular to a nitrochlorobenzene freezing point detection device and a testing method. Background Art

[0002] Nitrochlorobenzene is mainly used as an intermediate for synthesizing dyes, pesticides, medicines, developers and rubber antioxidants, etc. It is also a good high-boiling point solvent and a mild organic oxidant, playing an important role in industrial production. Many derivatives of nitrochlorobenzene also have broad market prospects. The preparation method of nitrochlorobenzene is as follows: in the presence of waste acid, chlorobenzene and mixed acid are used to generate acidic nitrochlorobenzene in a ring nitrator, and the acidic nitrochlorobenzene is neutralized, washed with water, and dried to obtain crude nitrochlorobenzene. The crude nitrochlorobenzene is crystallized and separated and purified by distillation to obtain the finished products of p-nitrochlorobenzene and o-nitrochlorobenzene, as well as the by-product m-nitrochlorobenzene.

[0003] During the production and storage process, the freezing point of the compound can help determine the appropriate operating temperature to avoid the substance solidifying or melting at an inappropriate temperature. Since the nitrochlorobenzene product obtained after separation and purification will be doped with a small amount of impurities, it is necessary to detect the freezing point of the product in real time to ensure product quality and stability during production and transportation.

[0004] The traditional detection methods are: (1) Principle: Physically lower the sample temperature. The temperature at which the solid phase begins to appear is the solidification point.

[0005] (2) Instruments: 500 mL beaker, magnetic stirrer, glass stirring rod, thermometer.

[0006] (3) Operation steps: First, add about 80 mL of the sample into a 500 mL beaker and insert a stirring rod and a thermometer; start stirring steadily without generating bubbles; crystallization begins to appear and read the temperature when it is relatively stable, retaining the result to one decimal place.

[0007] The traditional method for detecting the freezing point of chlorobenzene is a manual operation, which is time-consuming, labor-intensive and inefficient. In addition, the timing of the beginning of crystallization is easy to miss and difficult to judge, resulting in low detection accuracy. Summary of the invention

[0008] In order to solve the above problems, the present invention provides a nitrochlorobenzene freezing point detection device.

[0009] The technical solution adopted by the present invention is: A nitrochlorobenzene freezing point detection device comprises a base, on which a test device, a power supply and control module, and a refrigeration module are arranged; the refrigeration module is provided with a refrigerator, and the refrigerator is used to provide cold capacity for the test device; the power supply and control module comprises a power supply and a controller, and the power supply is used to supply power to the refrigeration module and the test device; The test device includes a fixed platform, a lifting drive device, a lifting platform, a test container and a bath. The bath is fixedly installed on the upper side of the fixed platform, and its upper end is open. The bath is filled with a cooling medium, and the cooling medium is connected to a refrigerator through a pipeline. The lifting platform is located above the bath, and the test container is installed on the lifting platform. The lifting platform is driven to rise and fall by the lifting drive device. When the lifting platform descends, the lower part of the test container can be immersed in the cooling medium of the bath. The test container includes a test bottle, a stirring motor, an agitator, a temperature sensor, a torque sensor, a test bottle cap and a drop-adding meter. The test bottle is provided with scale lines. The test bottle cap is fixedly installed at the open end of the test bottle. The stirring motor of the agitator is installed on the test bottle cap. The motor shaft extends vertically downward and is connected to the stirring shaft through the torque sensor. The lower end of the stirring shaft extends into the test bottle to connect the stirring blade. The temperature sensor is inserted into the test bottle cap, and its contact extends into the test bottle. The drop-adding meter is installed in the installation hole of the test bottle cap and is used to drop the test sample into the test bottle. The freezer, lift, stirring motor, stirrer, torque sensor and temperature sensor are all connected to the controller.

[0010] The above technical solution can replace manual automatic detection of the freezing point of nitrochlorobenzene, and the detection accuracy and detection efficiency are greatly improved. The detection principle of the present invention is: when the test sample in the test bottle, referred to as the sample, is added to the set volume; the test bottle is driven by the lifting platform to drop into the bath, and the sample is completely immersed in the cooling medium. At this time, the stirring motor starts to work, the stirrer stirs the sample, and the controller detects the torque value of the stirring shaft detected by the torque sensor in real time. Before reaching the freezing point, the sample is in a flowing state, the stirring force of the stirrer is small, and the torque value is low; when the sample begins to crystallize, the torque value of the stirring shaft suddenly increases. At this time, the controller stores the temperature value detected by the temperature sensor, which is the freezing point temperature of the sample.

[0011] Furthermore, it also includes a connecting hose and a feeding pump, the dripping meter is connected to the feeding pump through the connecting hose, and the feeding pump is connected to the nitrochlorobenzene storage tank.

[0012] By adopting the above technical solution, using a feed pump and a connecting hose, the freezing point of the material in the nitrochlorobenzene storage tank can be detected at any time to ensure the stability and safety of the product during storage.

[0013] Furthermore, there are three test containers, which are evenly distributed on the lifting platform in a circumferential direction. The drop-type metering instruments of the three test containers are respectively connected to three feeding pumps through three connecting hoses, and the three feeding pumps are respectively connected to the p-nitrochlorobenzene storage tank, the o-nitrochlorobenzene storage tank and the m-nitrochlorobenzene storage tank.

[0014] By adopting the above technical solution, the freezing points of the three products can be detected respectively, and the working efficiency is high.

[0015] Furthermore, according to the nitrochlorobenzene freezing point detection device according to claim 1, it is characterized in that a plurality of guide rods are also installed on the fixed platform, the lifting platform is slidably arranged on the guide rods, and the guide rods are evenly distributed on the periphery of the bath.

[0016] By adopting the above technical solution, the lifting platform is lifted and lowered under the guidance of the guide rod, thereby improving the stability of the lifting.

[0017] Furthermore, the lifting drive device includes a lift, which is installed inside the fixed platform, and the telescopic rod of the lift passes upward through the center hole of the bathtub and is connected to the lifting platform.

[0018] By adopting the above technical solution, the lifting and lowering movement of the lifting platform can be realized, and the elevator is used as the driving force, so that the structure of the entire test device is compact.

[0019] Furthermore, the lifting drive device includes a driving cylinder, which is installed on the base through a bracket, and the cylinder piston rod extends vertically downward to connect to the lifting platform.

[0020] By adopting the above technical solution, the lifting movement of the lifting platform can be realized, and a driving cylinder is used as a driving force. The cylinder is installed outside the bathtub, which can simplify the bathtub structure.

[0021] Furthermore, the test bottle is threadedly connected to the test bottle cap, so that the test bottle can be easily disassembled and cleaned.

[0022] Furthermore, the test container is fixedly inserted on the lifting platform through the test bottle, and the lower part of the test bottle extends out from the bottom surface of the lifting platform, so that the disassembly and assembly of the test container is convenient.

[0023] The present invention also provides a test method for detecting the freezing point of nitrochlorobenzene using any one of the above-mentioned nitrochlorobenzene freezing point detection devices, comprising: a controller determines whether the test sample has reached the freezing point based on the torque value of the stirring shaft; when the test sample reaches the freezing point, the controller stores the measured temperature of the temperature sensor, which is the freezing point temperature of the test sample.

[0024] Further, the test method comprises the following steps connected in sequence: Step 1) Start the refrigerator to precool the cooling medium in the bath to a set temperature; Step 2) dripping the test sample into the test bottle through a drip meter, and controlling the amount of the sample added by the scale line on the test bottle; Step 3) Start the lift, and the lift table drives the test container down. When the sample in the test bottle is completely immersed in the cooling medium of the bath, the lifting stops. At the same time, start the stirring motor to stir the sample, the temperature sensor detects the temperature of the sample, and the torque sensor detects the torque of the stirring shaft. Step 4) When the controller detects that the torque value of the stirring shaft suddenly increases, it means that the sample has reached the solidification point. At this time, the stirring motor stops working, and the controller stores the detection result of the temperature sensor; Step 5) Start the lift again, and the lift table and test container rise and return to their initial positions.

[0025] Beneficial effects of the present invention: 1. The device has a compact structure and high reliability. It can replace manual automatic detection of the freezing point of nitrochlorobenzene with high detection efficiency and accuracy.

[0026] 2. The method of the present invention has high measurement accuracy and good repeatability. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a structural diagram of a nitrochlorobenzene freezing point detection device in Example 1.

[0028] Figure 2 for Figure 1 Top view of the .

[0029] Figure 3 This is a structural diagram of the test container of Example 1.

[0030] Figure 4 This is a state diagram of the detection device of Example 1 when the sample is added.

[0031] Figure 5 This is a structural diagram of a nitrochlorobenzene freezing point detection device according to Example 2. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the present invention more clear, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and a preferred implementation manner. Example 1

[0033] See also Figure 1-Figure 4 This embodiment provides a nitrochlorobenzene freezing point detection device, including a base 1, a test device 10, a power supply and control module 20 and a freezing module 30.

[0034] The base 1 is used to install the test device 10, the power supply and control module 20 and the freezing module 30. For easy operation and connection, the test device 10 is installed in the middle part of the base 1, and the power supply and control module 20 and the freezing module 30 are installed on the left and right sides of the test device 10 respectively. A refrigerator (not shown in the figure) is provided in the freezing module 30, and the refrigerator is used to provide cooling for the test device. The power supply and control module 20 includes a power supply and a controller, and the power supply is used to power the freezing module 30 and the test device 10; in this embodiment, the power supply voltage is 220V±10%, and the power is 50Hz. The controller is used to control the automatic operation process of the sample device. In this embodiment, the controller model is ISL81401.

[0035] The test apparatus 10 includes a fixing table 11 , an elevator 16 , an elevator 15 , a test container 14 , and a bath 12 .

[0036] The fixing platform 11 is fixedly mounted on the base 1 by screws. The interior of the fixing platform 11 is a hollow structure, and a through hole for installing the elevator is provided in the center of the upper side thereof. The bath 12 is fixedly mounted on the upper side of the fixing platform 11 by embedding. Preferably, the bath 12 is a glass bath for easy observation. The upper end of the glass bath is open, and an equal-height glass tube is installed in the middle. The lower end of the glass tube passes through the glass bath and is flush with the bottom surface of the glass bath. The space surrounded by the glass tube and the side wall of the glass bath is filled with cooling medium; the outer wall of the glass bath is provided with an inlet and outlet for cooling medium (not shown in the figure), and the cooling medium is connected to the refrigerator through a pipe connecting the inlet and outlet.

[0037] Eight guide rods 13 are vertically installed on the outer edge of the side surface of the fixed platform, and the eight guide rods 13 are evenly distributed on the periphery of the bath 12; a lifting platform 15 is slidably connected to the eight guide rods 13 and is located above the bath 12. Three test containers 14 are installed on the lifting platform 15, and an elevator 16 is installed in the central cavity of the fixed platform 11. The telescopic rod of the elevator freely passes through the glass tube of the glass bath vertically upward and is connected to the lifting platform 15.

[0038] The test container 14 includes a test bottle 140, an agitator, a temperature sensor 143, a torque sensor, a test bottle cap 144 and a drop-type meter 145. The test bottle 140 is engraved with scale lines, and the amount of test sample added can be accurately controlled by the scale lines. Preferably, the test bottle 140 is a glass bottle for easy observation; the test bottle cap 144 is preferably a wooden cap for easy installation of the stirring motor 141, the temperature sensor 143 and the drop-type meter 145. The test bottle cap 144 is threadedly connected to the open end of the test bottle, and the test container 14 is fixedly inserted on the lifting platform 15 through the test bottle 140. The lower part of the test bottle 140 extends from the bottom surface of the lifting platform, and the test bottle cap 144 is stuck in the countersunk hole of the lifting platform 15. The agitator includes a stirring motor 141 , a stirring shaft and a stirring blade 142 ; the stirring motor 141 is fixedly mounted on the test bottle cap 144 , the motor shaft extends vertically downward and is connected to the stirring shaft through a torque sensor, and the lower end of the stirring shaft extends into the test bottle 140 and is connected to the stirring blade 142 .

[0039] The temperature sensor 143 is inserted into the test bottle cap 144, and its contact extends into the test bottle 410. In this embodiment, the temperature sensor is a PT100 temperature probe.

[0040] The drop-adding meter 145 is installed in the mounting hole of the test bottle cap, and its inlet end is used to connect a hose (not shown in the figure), and the hose is connected to the nitrochlorobenzene storage tank through a feeding pump (not shown in the figure). The preferred hose is a PVC transparent steel wire hose. In this embodiment, the drop-adding meter is a DZDR-50 type.

[0041] In this embodiment, the dripping metering instruments of the three test containers 14 are respectively connected to the three feeding pumps through three connecting hoses, and the three feeding pumps are respectively connected to the p-nitrochlorobenzene storage tank, the o-nitrochlorobenzene storage tank and the m-nitrochlorobenzene storage tank. Example 2

[0042] See also Figure 5 This embodiment is basically the same as Embodiment 1, except that: The lifting drive device includes a driving cylinder 17, which is mounted on the base 1 through a bracket, and a cylinder piston rod extends vertically downward to connect the lifting platform 15. The bath 12 is a complete structure.

[0043] The driving cylinder 17, the refrigerator, the elevator 16, the stirring motor 141, the stirrer 142, and the temperature sensor 143 are all connected to the controller. The controller determines whether the test sample has reached the freezing point according to the resistance value of the stirring motor 141. When the test sample reaches the freezing point, the controller stores the measured temperature of the temperature sensor 143, which is the freezing point temperature of the test sample. Example 3

[0044] The method for detecting the freezing point of nitrochlorobenzene using the detection device described in Example 1 or 2 specifically comprises the following steps connected in sequence: Step 1) Start the refrigerator to precool the cooling medium in the bath 12 to a set temperature; the sample temperature is usually 16-26°C, and the temperature of the cooling medium can be reduced to about 10°C; Step 2) The test sample is dripped into the test bottle 140 through the drip meter 145, and the amount of the sample added is controlled by the scale line on the test bottle; the amount of the sample added is 2 ml.

[0045] Step 3) Start the lifting drive device, the lifting platform 15 drives the test container 14 to descend, and the lifting stops when the sample in the test bottle 140 is completely immersed in the cooling medium of the bath; at the same time, start the stirring motor 141 to stir the sample, and the temperature sensor 143 detects the temperature of the sample; Step 4) When the controller detects that the torque of the stirring shaft suddenly increases, it means that the sample has reached the solidification point. At this time, the stirring motor 141 stops working, and the controller stores the detection result of the temperature sensor 143; Step 5) The lifting drive device is started again, and the lifting platform 15 and the test container 14 rise and return to the initial position.

[0046] The freezing point of p-nitrochlorobenzene stored in a p-nitrochlorobenzene storage tank was measured using the above method. The test results are shown in Table 1 below.

[0047]

[0048] From the test results in Table 1, it can be seen that the method of the present invention has high detection accuracy and good repeatability.

[0049] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications are also within the protection scope of the present invention.

Claims

1. A nitrochlorobenzene freezing point detection device, comprising a base (1), characterized in that: A test device (10), a power supply and control module (20), and a freezing module (30) are arranged on the base (1); A refrigerator is provided in the freezing module (30), and the refrigerator is used to provide cooling for the test device; The power supply and control module (20) comprises a power supply and a controller, and the power supply is used to supply power to the freezing module (30) and the test device (10); The test device (10) comprises a fixed platform (11), a lifting drive device, a lifting platform (15), a test container (14) and a bath (12). The bath (12) is fixedly mounted on the upper side of the fixed platform (11) and has an open upper end. The bath is filled with a cooling medium (2), which is connected to a refrigerator via a pipeline. The lifting platform (15) is located above the bath (12). The test container (14) is mounted on the lifting platform (15). The lifting platform (15) is driven to move up and down by the lifting drive device. When the lifting platform is lowered, the lower part of the test container (14) can be immersed in the cooling medium in the bath (12). The test container (14) comprises a test bottle (140), a stirrer, a temperature sensor (143), a torque sensor, a test bottle cap (144) and a drop-adding meter (145), wherein the test bottle is provided with scale lines, the test bottle cap is fixedly mounted on the open end of the test bottle, a stirring motor (141) of the stirrer is mounted on the test bottle cap, the motor shaft extends vertically downward and is connected to the stirring shaft through the torque sensor, the lower end of the stirring shaft extends into the test bottle and is connected to the stirring blade (142), the temperature sensor is inserted into the test bottle cap, and its contact extends into the test bottle, and the drop-adding meter (145) is mounted in the mounting hole of the test bottle cap and is used to drop the test sample into the test bottle; The refrigerator, the elevator, the stirring motor (141), the stirrer (142), the torque sensor, and the temperature sensor (143) are all connected to the controller.

2. A nitrochlorobenzene freezing point detection device according to claim 1, characterized in that: It also includes a connecting hose and a feeding pump. The drop-adding meter (145) is connected to the feeding pump via the connecting hose, and the feeding pump is connected to the nitrochlorobenzene storage tank.

3. A nitrochlorobenzene freezing point detection device according to claim 2, characterized in that: There are three test containers (14), which are evenly distributed on the lifting platform (15) in the circumferential direction. The drop-type metering instruments of the three test containers are respectively connected to three feed pumps through three connecting hoses, and the three feed pumps are respectively connected to the p-nitrochlorobenzene storage tank, the o-nitrochlorobenzene storage tank and the m-nitrochlorobenzene storage tank.

4. A nitrochlorobenzene freezing point detection device according to claim 1, characterized in that: A nitrochlorobenzene freezing point detection device according to claim 1, characterized in that a plurality of guide rods (13) are also installed on the fixed platform (11), and the lifting platform (15) is slidably arranged on the guide rods, and the guide rods are evenly distributed on the periphery of the bath (12).

5. A nitrochlorobenzene freezing point detection device according to claim 1, characterized in that: The lifting drive device comprises a lift (16), the lift (16) being installed inside the fixed platform (11), and the lift telescopic rod passing upward through the central hole of the bath (12) and connected to the lift platform (15).

6. A nitrochlorobenzene freezing point detection device according to claim 1, characterized in that: The lifting drive device comprises a driving cylinder, which is mounted on a base (1) via a bracket, and a cylinder piston rod extends vertically downward to connect to a lifting platform (15).

7. A nitrochlorobenzene freezing point detection device according to claim 1, characterized in that: The test bottle (140) is threadably connected to the test bottle cap (144).

8. A nitrochlorobenzene freezing point detection device according to claim 1, characterized in that: The test container (14) is fixedly inserted on the lifting platform (15) through the test bottle (140), and the lower part of the test bottle extends out from the bottom surface of the lifting platform.

9. A method for testing the freezing point of nitrochlorobenzene using a freezing point detection device of any one of claims 1 to 8, characterized in that: The controller determines whether the test sample has reached the freezing point according to the torque value of the stirring shaft. When the test sample reaches the freezing point, the controller stores the measured temperature of the temperature sensor (143), which is the freezing point temperature of the test sample.

10. The testing method according to claim 9, characterized in that: The specific steps include the following steps connected in sequence: Step 1) starting the refrigerator to precool the cooling medium in the bath (12) to a set temperature; Step 2) the test sample is dripped into the test bottle (140) through a drip meter (145), and the amount of the sample added is controlled by the scale lines on the test bottle; Step 3) starting the lift, the lift platform (15) drives the test container (14) to descend, and the lifting and lowering stops when the sample in the test bottle (140) is completely immersed in the cooling medium of the bath; at the same time, starting the stirring motor (141) to stir the sample, the temperature sensor (143) to detect the temperature of the sample, and the torque sensor to detect the torque of the stirring shaft; Step 4) When the controller detects that the torque value of the stirring shaft suddenly increases, it indicates that the sample has reached the solidification point. At this time, the stirring motor (141) stops working, and the controller stores the detection result of the temperature sensor (143); Step 5) The lift is started again, and the lift platform (15) and the test container (14) rise and return to their initial positions.

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