Device and method for detecting content of trace ammonia, formic acid and ammonium formate in formamide

Abstract

The invention discloses a device for detecting the content of trace ammonia, formic acid and ammonium formate in formamide, the device comprises a magnetic stirrer and an absolute methanol solution beaker, one side of the upper end of the magnetic stirrer is provided with a temperature control unit, and the outer edge of the bottom of the temperature control unit is provided with an inner heating strip; an absolute methanol solution beaker is arranged on the inner side of the temperature control unit, and a polytetrafluoroethylene magnetic rotor is arranged at the middle end of the interior of the absolute methanol solution beaker; according to the method for detecting the content of the trace ammonia, the formic acid and the ammonium formate in the formamide, the absolute methanol solution is used as a solvent to dissolve the formamide by utilizing the characteristics that the absolute methanol solution is mutually soluble with the formamide and is high in solubility, so that proton migration during acid-base titration can be improved, an obvious titration jump is achieved, a titration jump point is accurately determined by utilizing a PH meter, and the accuracy of the titration jump point is improved. The content of trace ammonia, formic acid and ammonium formate in formamide can be accurately measured through calculation, and the problem that the content of ammonia, formic acid and ammonium formate in formamide is high and unstable is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of formamide detection, and in particular to a device and method for detecting the content of trace ammonia, formic acid and ammonium formate in formamide; Background Art

[0002] Formamide is an organic compound with the molecular formula CH3NO. It is a colorless and transparent liquid with a slight ammonia smell. It is a raw material for synthetic medicines, spices, dyes, etc. It can also be used as a solvent for synthetic fiber spinning, plastic processing, and the production of wood casein ink. It is also an excellent organic solvent. It is mainly used in the spinning of acrylonitrile copolymers and ion exchange resins, as well as antistatic or conductive coatings for plastic products. In addition, it is also used to separate chlorosilanes and purify oils. Formamide can undergo a variety of reactions. In addition to the three hydrogen atoms involved in the reaction, it can also undergo dehydration, CO removal, amino group introduction, acyl group introduction, and cyclization reactions.

[0003] When formamide is used in production, ammonia, formic acid, and ammonium formate are by-products produced during the production process of formamide, and their content needs to be tested. Ammonia, formic acid, and ammonium formate are common test items for formamide.

[0004] Conventional methods for detecting trace amounts of ammonia, formic acid, and ammonium formate in formamide are generally achieved through the following two steps: first, use acid-base titration to detect ammonia and formic acid; then use formaldehyde method or ion chromatography to detect ammonium formate in formamide;

[0005] The existing detection methods have complicated operation steps, low accuracy, time-consuming and labor-intensive, and high detection costs:

[0006] 1. When using acid-base titration to detect ammonia and formic acid, since formamide itself contains a certain alkalinity, it will affect the detection accuracy of ammonia and formic acid, and the detection is not accurate enough; and formamide is an organic substance. Although it is miscible with water, its solubility is poorer than that of other organic solvents. Moreover, weak acids and weak bases such as ammonia, formic acid, and ammonium formate have no obvious titration jump with salts in water, making it difficult to grasp the titration end point;

[0007] 2. When using the formaldehyde method to detect ammonium formate, the method is complicated to operate, and the repeatability of detecting the content of ammonium formate in formamide is not high, which is not ideal;

[0008] When using ion chromatography to detect ammonium formate, an ion chromatograph is required. However, the cost is high for the detection of trace amounts of ammonium formate in formamide, and the detected ammonium formate content is more than twice higher than the actual content, so the detection of trace amounts is poor. Summary of the invention

[0009] The object of the present invention is to provide a device and method for detecting the content of trace ammonia, formic acid and ammonium formate in formamide, so as to solve the problems of the above-mentioned existing washing water treatment device proposed in the above-mentioned background technology;

[0010] To achieve the above-mentioned purpose, the present invention provides the following technical scheme: a device for detecting the content of trace ammonia, formic acid and ammonium formate in formamide, comprising a magnetic stirrer and a beaker of anhydrous methanol solution, wherein a temperature control unit is arranged on one side of the upper end of the magnetic stirrer, and an inner heating strip is arranged on the inner edge of the bottom of the temperature control unit, an anhydrous methanol solution beaker is arranged on the inner side of the temperature control unit, a polytetrafluoroethylene magnetic rotor is arranged on the inner middle end of the anhydrous methanol solution beaker, a lifting gas rod is arranged on one side of the outer side of the magnetic stirrer, and a connecting support plate is installed on the top of the lifting gas rod, and the connecting support plate is arranged on the inner side of the temperature control unit. One end of the plate extends to the upper position of the anhydrous methanol solution beaker, a connecting screw sleeve is installed on the inner side of the connecting support plate, and a slotted oval plate is detachably installed on the bottom of the connecting screw sleeve, a burette is installed on the other end of the inner side of the connecting support plate, and a glass PH composite electrode is sunk inside the anhydrous methanol solution beaker, the burette and the internal positions of the anhydrous methanol solution beaker cooperate with each other, an inner groove is opened at the bottom of the slotted oval plate, a cross connecting frame is arranged on the top of the slotted oval plate, and a mounting screw is installed in the middle of the cross connecting frame, which is fixedly connected to the connecting screw sleeve;

[0011] The top of the glass PH composite electrode is connected to a connecting wire harness, and the other end of the connecting wire harness is electrically connected to a PH meter;

[0012] Furthermore, a speed adjustment knob is provided on one side of the upper portion of the magnetic stirrer, and a temperature adjustment knob is provided on the other side of the upper portion of the magnetic stirrer;

[0013] Furthermore, the magnetic stirrer can drive the polytetrafluoro magnetic rotor to rotate, and the polytetrafluoro magnetic rotor is arranged in the middle of the anhydrous methanol solution beaker;

[0014] Furthermore, the polytetrafluoroethylene magnetic rotor cooperates with the upper and lower positions of the slotted elliptical plate through the inner groove, and the slotted elliptical plate forms a lifting structure by connecting the support plate and the lifting gas rod;

[0015] Furthermore, the connecting support plate and the glass PH composite electrode form an upper and lower sleeve connection;

[0016] Furthermore, the temperature control unit and the anhydrous methanol solution beaker are wrapped and connected, and the sizes of the temperature control unit and the anhydrous methanol solution beaker fit each other, and the anhydrous methanol solution beaker and the internal heating strip fit each other;

[0017] Furthermore, the slotted oval plate is made of plastic material;

[0018] Furthermore, the slotted oval plate can be replaced by an electric clamp or a magnetic attraction piece;

[0019] A method for detecting the content of trace ammonia, formic acid and ammonium formate in formamide, comprising:

[0020] Step 1: Add appropriate amount of anhydrous methanol and appropriate amount of formamide into a beaker of anhydrous methanol solution in sequence;

[0021] Step 2: Then, a magnetic stirrer is used to drive a polytetrafluoroethylene magnetic rotor to rotate so that the anhydrous methanol solution and formamide are evenly mixed;

[0022] Step 3, inserting the glass pH composite electrode into the beaker of anhydrous methanol solution to contact the solvent;

[0023] Step 4: Then, using hydrochloric acid-methanol as a standard titration solution, an acid-base titration detection operation is performed on the inner formamide through a burette, and the titration jump point is accurately determined using a pH meter, and the content of trace ammonia, formic acid, and ammonium formate in formamide is accurately determined by calculation;

[0024] Step 5: After the content is determined, the lifting gas rod on one side is controlled to descend, driving the slotted elliptical plate to move downward to contact the polytetrafluoroethylene magnetic rotor, and gradually pressing downward, causing the polytetrafluoroethylene magnetic rotor to squeeze the inner groove at the bottom of the slotted elliptical plate (13), so that the polytetrafluoroethylene magnetic rotor is squeezed into the slotted elliptical plate;

[0025] Step 6: Then, the polytetrafluoroethylene magnetic rotor is lifted up by the lifting gas rod to facilitate the transfer or treatment of the solution in the anhydrous methanol solution beaker;

[0026] Compared with the prior art, the invention has the following beneficial effects: the device and method for detecting the content of trace ammonia, formic acid and ammonium formate in formamide, by utilizing the characteristics of anhydrous methanol solution being miscible with formamide and having strong solubility, and utilizing anhydrous methanol as a solvent to dissolve formamide, can improve proton migration during acid-base titration, achieve an obvious titration jump, and accurately determine the titration jump point using a pH meter, and accurately determine the content of trace ammonia, formic acid and ammonium formate in formamide through calculation, solve the problem of high and unstable content of ammonia, formic acid and ammonium formate in formamide, do not need to detect ammonia, formic acid and ammonium formate in multiple steps, and save cost and time;

[0027] Anhydrous methanol is the largest by-product in the production of formamide and is miscible with formamide and has strong solubility;

[0028] Anhydrous methanol can self-transfer protons in proton migration, and its acidity and alkalinity are close. It is a very good neutral substance with high polarity. Compared with organic solvents such as dimethylformamide, benzene, chloroform, and carbon tetrachloride, some are alkaline, some are acidic, and some cannot donate protons.

[0029] In the traditional testing process, some substances in the formamide sample will undergo hydrolysis reaction in water to produce formic acid and ammonium formate, which will affect the accuracy of the test results. However, the use of anhydrous methanol as a solvent can avoid the above situation, save the purchase of large instruments and operating costs, simplify the steps, and improve accuracy and timeliness;

[0030] By using the lifting structure in conjunction with the magnetic stirrer, the polytetrafluoroethylene magnetic rotor can be rotated contactlessly in the beaker of anhydrous methanol solution, thereby ensuring uniformity during titration mixing, making the test results more accurate, and reducing or avoiding errors in trace detection;

[0031] The lifting structure adopts pneumatic mode, which can drive the rubber slotted oval plate to descend to contact the polytetrafluoromagnetic rotor. The arc surfaces on both sides of the slotted oval plate and the opening in the middle are used to make the polytetrafluoromagnetic rotor enter the slotted oval plate under pressure. After being free from pressure, the slotted oval plate can salvage and filter the polytetrafluoromagnetic rotor, thereby ensuring the automation structure and simple operation structure in the detection process and improving convenience. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the three-dimensional structure when the sewage tank and the reciprocating track assembly are combined in the present invention;

[0033] Figure 2 It is a schematic diagram of the three-dimensional structure of the reciprocating track assembly and the driving motor during transmission in the present invention;

[0034] Figure 3 is a processing flow chart of the washing water purification method of the present invention;

[0035] In the figure: 1. magnetic stirrer; 2. temperature control unit; 3. pH meter; 4. speed adjustment knob; 5. temperature adjustment knob; 6. connection harness; 7. glass pH composite electrode; 8. lifting gas rod; 9. connection support plate; 10. connection screw sleeve; 11. burette; 12. beaker of anhydrous methanol solution; 13. slotted oval plate; 1301. inner groove; 1302. cross connection frame; 1303. mounting screw; 14. inner heating strip; 15. polytetrafluoro magnetic rotor; DETAILED DESCRIPTION

[0036] In the description of the present invention, unless otherwise specified, "plurality" means two or more than two; the directions or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific direction, be constructed and operate in a specific direction, and therefore cannot be understood as limiting the present invention; in addition, the terms "first", "second", "third", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance;

[0037] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; for ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances;

[0038] like Figure 1-3 As shown, the present invention provides a technical solution: a device and method for detecting the content of trace ammonia, formic acid and ammonium formate in formamide, comprising a magnetic stirrer 1 and an anhydrous methanol solution beaker 12, a temperature control unit 2 is arranged on one side of the upper end of the magnetic stirrer 1, and an inner heating strip 14 is arranged on the inner edge of the bottom of the temperature control unit 2, an anhydrous methanol solution beaker 12 is arranged on the inner side of the temperature control unit 2, a polytetrafluoroethylene magnetic rotor 15 is arranged on the inner middle end of the anhydrous methanol solution beaker 12, a lifting gas rod 8 is arranged on one side of the outer side of the magnetic stirrer 1, and a connecting support plate 9 is installed on the top of the lifting gas rod 8, and one end of the connecting support plate 9 extends to the anhydrous methanol solution beaker 12. A connecting screw sleeve 10 is installed on the inner side of the connecting support plate 9 above the water-methanol solution beaker 12, and a slit oval plate 13 is detachably installed on the bottom of the connecting screw sleeve 10, a burette 11 is installed on the other end of the inner side of the connecting support plate 9, and a glass PH composite electrode 7 is sunk inside the anhydrous methanol solution beaker 12, the burette 11 and the internal positions of the anhydrous methanol solution beaker 12 cooperate with each other, an inner groove 1301 is opened at the bottom of the slit oval plate 13, a cross connecting frame 1302 is arranged on the top of the slit oval plate 13, and a mounting screw 1303 is installed in the middle of the cross connecting frame 1302, which is fixedly connected to the connecting screw sleeve 10;

[0039] The top of the glass PH composite electrode 7 is connected with a connecting harness 6, and the other end of the connecting harness 6 is electrically connected with a PH meter 3; a speed adjustment knob 4 is arranged on one side of the upper part of the magnetic stirrer 1, and a temperature adjustment knob 5 is arranged on the other side of the upper part of the magnetic stirrer 1; the magnetic stirrer 1 can drive the polytetrafluoroethylene magnetic rotor 15 to rotate, and the polytetrafluoroethylene magnetic rotor 15 is arranged in the middle of the anhydrous methanol solution beaker 12; the polytetrafluoroethylene magnetic rotor 15 cooperates with the upper and lower positions of the slit elliptical plate 13 through the inner groove 1301, and the slit elliptical plate 13 forms a lifting structure through the connecting support plate 9 and the lifting gas rod 8; the connecting support plate 9 and the glass PH composite electrode 7 form an upper and lower sleeve connection; the temperature control unit 2 and the anhydrous methanol solution beaker 12 form a wrapping connection, and the sizes of the temperature control unit 2 and the anhydrous methanol solution beaker 12 are mutually embedded, and the anhydrous methanol solution beaker 12 and the inner heating strip 14 fit each other; the slit elliptical plate 13 is made of plastic material;

[0040] By utilizing the characteristics of anhydrous methanol solution that is mutually soluble with formamide and has strong solubility, and using anhydrous methanol as a solvent to dissolve formamide, proton migration during acid-base titration can be improved to achieve a significant titration jump, and the titration jump point can be accurately determined using a pH meter, and the content of trace ammonia, formic acid, and ammonium formate in formamide can be accurately determined by calculation, thereby solving the problem of high and unstable content of ammonia, formic acid, and ammonium formate in formamide, and there is no need to detect ammonia, formic acid, and ammonium formate in multiple steps, saving cost and time;

[0041] Anhydrous methanol is the largest by-product in the production of formamide and is miscible with formamide and has strong solubility;

[0042] Anhydrous methanol can self-transfer protons in proton migration, and its acidity and alkalinity are close. It is a very good neutral substance with high polarity. Compared with organic solvents such as dimethylformamide, benzene, chloroform, and carbon tetrachloride, some are alkaline, some are acidic, and some cannot donate protons.

[0043] In the traditional testing process, some substances in the formamide sample will undergo hydrolysis reaction in water to produce formic acid and ammonium formate, which will affect the accuracy of the test results. However, the use of anhydrous methanol as a solvent can avoid the above situation, save the purchase of large instruments and operating costs, simplify the steps, and improve accuracy and timeliness;

[0044] By using the lifting structure in conjunction with the magnetic stirrer 1, the polytetrafluoroethylene magnetic rotor 15 is rotated contactlessly in the anhydrous methanol solution beaker 12, thereby ensuring uniformity during titration mixing, making the test result more accurate, and reducing or avoiding errors in trace detection;

[0045] The lifting structure adopts a pneumatic method to drive the rubber slotted elliptical plate 13 to descend to contact the polytetrafluoromagnetic rotor 15. The arc surfaces on both sides of the slotted elliptical plate 13 and the opening slit in the middle are used to make the polytetrafluoromagnetic rotor 15 enter the slotted elliptical plate 13 under pressure. After that, the slotted elliptical plate 13 can salvage and filter the polytetrafluoromagnetic rotor 15 when it is not under pressure, thereby ensuring the automation structure and simple operation structure in the detection process and improving convenience.

[0046] Further, the slotted oval plate 13 can be replaced with an electric clamp or a magnetic suction piece, and the electric clamp is used to grab the polytetrafluoro magnetic rotor 15, or the magnetic suction piece is used to magnetically suck out the polytetrafluoro magnetic rotor 15 by using the magnetic suction characteristics, so as to salvage and filter the polytetrafluoro magnetic rotor 15, thereby ensuring the automation structure and simple operation structure in the detection process and improving convenience;

[0047] In summary, the device and method for detecting the content of trace ammonia, formic acid and ammonium formate in formamide, when used, firstly, add an appropriate amount of anhydrous methanol and an appropriate amount of formamide into the anhydrous methanol solution beaker 12 in sequence; then, the magnetic stirrer 1 can be used to drive the polytetrafluoroethylene magnetic rotor 15 to rotate, so that the anhydrous methanol solution and formamide are evenly mixed, and the magnetic force can be adjusted by the speed adjustment knob 4 to adjust the rotation rate of the polytetrafluoroethylene magnetic rotor 15; then, the polytetrafluoroethylene magnetic rotor 15 is extended into the anhydrous methanol solution beaker 12 to contact the glass pH composite electrode 7 with the solvent, and then, hydrochloric acid-methanol is used as a standard titration solution, and the formamide inside is subjected to an acid-base titration detection operation through a burette (11), so as to accurately determine the titration jump point using a pH meter, and thereby accurately determine the content of trace ammonia, formic acid and ammonium formate in formamide through calculation;

[0048] After the content is determined, the lifting gas rod 8 on one side is controlled to descend, driving the slotted elliptical plate 13 to move downward to contact the polytetrafluoromagnetic rotor 15, and gradually pressing down, so that the polytetrafluoromagnetic rotor 15 squeezes the inner groove 1301 at the bottom of the slotted elliptical plate 13, so that the polytetrafluoromagnetic rotor 15 is squeezed into the slotted elliptical plate 13; then the polytetrafluoromagnetic rotor 15 is salvaged and raised by the lifting gas rod 8, so as to facilitate the transfer or treatment of the solution in the anhydrous methanol solution beaker 12;

[0049] Or it is required to replace the slotted oval plate 13 with an electric clamp or a magnetic suction piece, and use the electric clamp to grab the polytetrafluoro magnetic rotor 15, or use the magnetic suction piece to magnetically absorb the polytetrafluoro magnetic rotor 15;

[0050] It can be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto; for ordinary technicians in this field, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A device for detecting the content of trace ammonia, formic acid and ammonium formate in formamide, comprising a magnetic stirrer (1) and a beaker of anhydrous methanol solution (12), characterized in that: A temperature control unit (2) is arranged on one side of the upper end of the magnetic stirrer (1), and an inner heating strip (14) is arranged on the inner edge of the bottom of the temperature control unit (2); an anhydrous methanol solution beaker (12) is arranged on the inner side of the temperature control unit (2); a polytetrafluoroethylene magnetic rotor (15) is arranged at the inner middle end of the anhydrous methanol solution beaker (12); a lifting gas rod (8) is arranged on one side of the outer side of the magnetic stirrer (1), and a connecting support plate (9) is installed on the top of the lifting gas rod (8), and one end of the connecting support plate (9) extends to the upper position of the anhydrous methanol solution beaker (12); a connecting screw sleeve (15) is installed on the inner side of the connecting support plate (9) 0), and a slotted elliptical plate (13) is detachably mounted on the bottom of the connecting screw sleeve (10), a burette (11) is mounted on the other end of the inner side of the connecting support plate (9), and a glass PH composite electrode (7) is sunk inside the anhydrous methanol solution beaker (12), the internal positions of the burette (11) and the anhydrous methanol solution beaker (12) cooperate with each other, an inner groove (1301) is formed on the bottom of the slotted elliptical plate (13), a cross connecting frame (1302) is arranged on the top of the slotted elliptical plate (13), and a mounting screw (1303) is mounted in the middle of the cross connecting frame (1302) and fixedly connected to the connecting screw sleeve (10); The top of the glass pH composite electrode (7) is connected to a connecting wire harness (6), and the other end of the connecting wire harness (6) is electrically connected to a pH meter (3).

2. The device for detecting the content of trace ammonia, formic acid and ammonium formate in formamide according to claim 1, characterized in that: A speed adjustment knob (4) is provided on one side of the upper part of the magnetic stirrer (1), and a temperature adjustment knob (5) is provided on the other side of the upper part of the magnetic stirrer (1).

3. The device for detecting the content of trace ammonia, formic acid and ammonium formate in formamide according to claim 1, characterized in that: The magnetic stirrer (1) can drive the polytetrafluoroethylene magnetic rotor (15) to rotate, and the polytetrafluoroethylene magnetic rotor (15) is arranged in the middle of the anhydrous methanol solution beaker (12).

4. The device for detecting the content of trace ammonia, formic acid and ammonium formate in formamide according to claim 1, characterized in that: The polytetrafluoroethylene magnetic rotor (15) cooperates with the upper and lower positions of the slotted elliptical plate (13) through the inner groove (1301), and the slotted elliptical plate (13) forms a lifting structure by connecting the support plate (9) and the lifting gas rod (8).

5. The device for detecting the content of trace ammonia, formic acid and ammonium formate in formamide according to claim 1, characterized in that: The connecting support plate (9) and the glass PH composite electrode (7) form an upper and lower sleeve connection.

6. The device for detecting the content of trace ammonia, formic acid and ammonium formate in formamide according to claim 1, characterized in that: The temperature control unit (2) and the anhydrous methanol solution beaker (12) are wrapped and connected, and the sizes of the temperature control unit (2) and the anhydrous methanol solution beaker (12) are mutually interlocked, and the anhydrous methanol solution beaker (12) and the internal heating strip (14) are mutually fitted.

7. The device for detecting the content of trace ammonia, formic acid and ammonium formate in formamide according to claim 1, characterized in that: The slotted oval plate (13) is made of plastic material.

8. The device for detecting the content of trace ammonia, formic acid and ammonium formate in formamide according to claim 1, characterized in that: The slotted oval plate (13) can be replaced by an electric clamp or a magnetic attraction piece.

9. A method for detecting the content of trace ammonia, formic acid and ammonium formate in formamide according to any one of claims 1 to 8, characterized in that: The method comprises: Step 1: add appropriate amount of anhydrous methanol and appropriate amount of formamide into an anhydrous methanol solution beaker (12) in sequence; Step 2: Then, the magnetic stirrer (1) is used to drive the polytetrafluoroethylene magnetic rotor (15) to rotate so that the anhydrous methanol solution and the formamide are evenly mixed; Step 3, the polytetrafluoroethylene magnetic rotor (15) is inserted into the anhydrous methanol solution beaker (12) so that the glass pH composite electrode (7) contacts with the solvent; Step 4: Then, using hydrochloric acid-methanol as a standard titration solution, an acid-base titration detection operation is performed on the formamide inside through a burette (11), and the titration jump point is accurately determined using a pH meter, and the content of trace ammonia, formic acid, and ammonium formate in the formamide is accurately determined by calculation; Step 5: After the content is determined, the lifting gas rod (8) on one side is controlled to descend, driving the slotted elliptical plate (13) to move downward to contact the polytetrafluoroethylene magnetic rotor (15), and gradually pressing downward, causing the polytetrafluoroethylene magnetic rotor (15) to squeeze the inner groove (1301) at the bottom of the slotted elliptical plate (13), so that the polytetrafluoroethylene magnetic rotor (15) is squeezed into the interior of the slotted elliptical plate (13); Step 6: Then, the polytetrafluoroethylene magnetic rotor (15) is lifted up by the lifting gas rod (8) to facilitate the transfer or treatment of the solution in the anhydrous methanol solution beaker (12).

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