Synthesis of phenyl semicarbazone and its recognition for iron ion

Abstract

Synthesis of a phenylaminourea and its recognition of iron ions. Benzaldehyde and aminourea hydrochloride were used as raw materials, and a carbon-based solid acid was used as a catalyst to synthesize phenylaminourea by grinding in a specific molar ratio. First, A mol of benzaldehyde and C mol of carbon-based solid acid (p-toluenesulfonic acid) were ground in a mortar. Then, B mol of aminourea hydrochloride was added, and grinding continued until the reaction was complete. The reaction progress was monitored by TLC during grinding. The ratio of A:B:C was (1~1.3):1:(0.05~0.2). After the reaction was complete, a small amount of methanol was added to the reaction vessel, and the catalyst was removed by filtration. The filtrate was then distilled under reduced pressure to obtain phenylaminourea. The catalyst was recovered and could be reused up to 5 times. The synthesized probe was prepared into a test solution using a solvent. Different cations were added to the test solution, and the changes in absorbance of the compound were observed by UV-Vis absorption spectroscopy to identify iron ions. 3+ Selective detection is performed; and the probe is effective against Fe. 3+ The detection is quite sensitive and has strong anti-interference capabilities.

Description

Technical Field

[0001] This invention relates to the field of chemical synthesis and to benzaldehyde Schiff base as a probe for recognizing receptors, which can selectively recognize Fe. 3+ It exhibits good resistance to interference from other cations. Specifically, it relates to a method for synthesizing a benzaldehyde Schiff base and its effect on Fe... 3+ Identification. Background Technology

[0002] Iron ions are the most abundant transition metal ions in the human body, playing vital physiological roles such as oxygen transport, gene regulation, electron transfer, and macrophage polarization. Insufficient iron levels can lead to health problems such as loss of appetite, anemia, frequent fatigue, and weakened immunity, thus affecting people's learning and work. Furthermore, when iron levels in the blood exceed safe limits, it can cause various related pathologies, such as tissue damage in different organs and the degradation of proteins, nucleic acids, and lipids due to the production of reactive oxygen species. In addition, the steel industry generates large amounts of iron ions, which accumulate in the environment, polluting water sources and soil and severely disrupting the ecological balance. Therefore, finding an effective method for detecting Fe is crucial. 3+ The method has become extremely urgent. Commonly used Fe 3+ Detection methods include atomic absorption spectroscopy, inductively coupled plasma mass spectrometry, and electrochemical methods. However, these methods are relatively complex, require expensive equipment, and are time-consuming, making them unsuitable for rapid and online monitoring. Therefore, it is necessary to develop a highly selective and sensitive method to detect Fe distributed in the environment and biological systems. 3+ Ions are very important. Probe methods that detect changes in absorbance using ultraviolet-visible absorption spectroscopy are widely used for the detection of metal ions due to their advantages such as simplicity, speed, low cost, and high sensitivity. Summary of the Invention

[0003] The purpose of this invention is to provide a method for selectively identifying Fe. 3+ Synthesis and application of probes for the selective identification of Fe by ultraviolet-visible absorption spectroscopy 3+ .

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A method for synthesizing a probe containing a benzaldehyde Schiff base includes the following steps:

[0006] Phenylacetamide was synthesized by grinding benzaldehyde and aminourea hydrochloride as raw materials and a carbon-based solid acid (p-toluenesulfonic acid) as a catalyst in a specific molar ratio. First, A mol of benzaldehyde and C mol of the carbon-based solid acid (p-toluenesulfonic acid) were ground in a mortar. Then, B mol of aminourea hydrochloride was added, and grinding continued until the reaction was complete. The reaction progress was monitored by TLC during the grinding process. After the reaction was complete, a small amount of methanol was added to the reaction vessel, the catalyst was removed by filtration, and the filtrate was distilled under reduced pressure to obtain phenylacetamide.

[0007] As in equation (1):

[0008]

[0009] A benzaldehyde-containing Schiff base probe is used to detect Fe. 3+ The ionic method includes the following steps:

[0010] Step 1) Prepare phenylaminourea to a concentration of 1×10 -4 The test solution with a concentration of mol / L;

[0011] Step 2) Prepare 1×10 -2 mol / L cation solution;

[0012] The cation solution and the test solution were mixed thoroughly to obtain the detection solution, and Fe was detected by ultraviolet-visible absorption spectroscopy. 3+ .

[0013] The cation is Al 3+ Zn 2+ Sn 2+ ,Mn 2+ Cu 2+ Li + ,Fe 2+ ,K + Ca 2+ ,Fe 3+ ,La 3+ Co 2+ Pb 2+ Ho 3+ Ni 2+ ,Bi 3+ .

[0014] Step 3) Mix the above-mentioned cation solution and the test solution thoroughly. The concentration of the test solution is 1×10⁻⁶. -4 mol / L; the concentration of the cation solution is 1×10⁻⁶. -2 mol / L.

[0015] Compared with other existing technologies, the present invention has the following beneficial effects:

[0016] The present invention provides a method for preparing a benzaldehyde-containing Schiff base, using benzaldehyde and aminourea hydrochloride as raw materials, and a carbon-based solid acid (p-toluenesulfonic acid) as a catalyst, to synthesize phenylaminourea via a grinding reaction, which can be used as Fe 3+ This highly selective ion probe for recognizing receptors also possesses strong anti-interference capabilities. This invention utilizes a carbon-based solid acid as a catalyst and employs a solid-phase grinding method for synthesis, which improves product yield, shortens the required time, simplifies operation, and is environmentally friendly. It represents a green and efficient method for synthesizing phenyl urea. Attached Figure Description

[0017] Figure 1 FT-IR of phenylaminourea;

[0018] Figure 2 The UV-Vis absorption spectrum of phenyl urea with added metal ions;

[0019] Figure 3 Adding p-Fe to phenyl urea 3+ Ion anti-interference properties;

[0020] Figure 4 phenyl urea for Fe 3+ Quantitative testing of ions;

[0021] Figure 5 For the time-dependent detection of Fe in phenyl urea 3+ The effect of light absorption intensity;

[0022] Figure 6 For the detection of Fe by pH-p-phenylaminourea 3+ The effect of light absorption intensity;

[0023] Figure 7 The effect of the number of times the carbon-based solid acid catalyst is reused on the yield of phenyl urea. Detailed Implementation

[0024] The present invention will be further described in detail below with reference to specific examples:

[0025] Example 1: Preparation of phenyl urea

[0026] Phenylacetamide was synthesized by grinding benzaldehyde and aminourea hydrochloride as raw materials and a carbon-based solid acid (p-toluenesulfonic acid) as a catalyst in a specific molar ratio. First, 1.2 mmol of benzaldehyde and 0.008 mmol of p-toluenesulfonic acid were ground in a mortar. Then, 1 mmol of aminourea hydrochloride was added, and grinding continued until the reaction was complete. The reaction progress was monitored by TLC during grinding. After the reaction was complete, a small amount of methanol was added to the reaction vessel, the catalyst was removed by filtration, and the filtrate was distilled under reduced pressure to obtain phenylacetamide.

[0027] IR(KBr)υ: 3261cm -1 3072cm -1 1690cm -1 1600cm -1 1428cm -1 1520cm -1 1646cm -1 1609cm -1 690cm -1 758cm -1 692cm -1 .

[0028] Example 2: Selective detection of cations by phenyl urea

[0029] A solution of phenylaminourea in methanol:H₂O = 5:5 was prepared to a concentration of 1×10⁻⁶. -4 The test solution was prepared by ultrasonic mixing with a concentration of 1 × 10⁻⁶ mol / L. The cation salts AlCl₃, ZnCl₂, SnCl₂, MnCl₂, CuCl₂, LiCl, FeCl₂, KCl, CaCl₂·2H₂O, FeCl₃, La(NO₃)₃·6H₂O, CoCl₂·6H₂O, Pb(NO₃)₂, Ho(NO₃)₃·6H₂O, Bi(NO₃)₃·5H₂O, and NiSO₄·6H₂O were dissolved in ultrapure water to prepare a solution with a concentration of 1 × 10⁻⁶ mol / L. -2 A mol / L cation solution was prepared. 3 mL of the phenylaminourea test solution was added to each sample tube. One sample tube was prepared as a blank control. 30 μL of each of the 16 cation solutions was added to the remaining 16 sample tubes. These 17 groups of sample tubes were ultrasonicated, mixed thoroughly, and then their UV-Vis absorption spectra were measured. From... Figure 2 It can be seen that the UV-Vis absorption spectrum shows an absorption peak at 279 nm when the test solution and the test solution are supplemented with 15 other cations; while the addition of Fe... 3+ The absorption peak at 279 nm shifted to 275 nm during ionization, and the absorption intensity was significantly enhanced. From Figure 2 It is not difficult to find that phenyl urea can selectively recognize Fe. 3+ ion.

[0030] Example 3: Phenylacetylaminourea on Fe 3+ Anti-interference detection

[0031] Phenylacetamide was dissolved in a methanol:H₂O = 5:5 solution to prepare a solution with a concentration of 1×10⁻⁶. -4The test solution was prepared by ultrasonic mixing with a concentration of 1 × 10⁻⁶ mol / L. The cation salts AlCl₃, ZnCl₂, SnCl₂, MnCl₂, CuCl₂, LiCl, FeCl₂, KCl, CaCl₂·2H₂O, FeCl₃, La(NO₃)₃·6H₂O, CoCl₂·6H₂O, Pb(NO₃)₂, Ho(NO₃)₃·6H₂O, Bi(NO₃)₃·5H₂O, and NiSO₄·6H₂O were dissolved in ultrapure water to prepare a solution with a concentration of 1 × 10⁻⁶ mol / L. -2 A mol / L cation solution. Add 3 mL of the phenylaminourea test solution to each sample tube. Prepare one sample tube as a blank control. Add 30 μL of the above 16 cation solutions to the remaining 16 sample tubes, and then add 30 μL of Fe to each sample tube. 3+ The 17 sample tubes were ultrasonicated to mix the ions, and then their ultraviolet-visible absorption spectra were measured. Figure 3 As can be seen, when 15 other cation solutions were added, the absorption intensity of the test solution was similar to that of the phenyl urea test solution. Only when Fe was added did the absorption intensity of the test solution change. 3+ The absorbance intensity increased significantly during ionization, indicating that the phenylaminourea test solution can selectively recognize Fe. 3+ Ions; Fe is added again after adding a cationic solution to phenylaminourea. 3+ Ionic solutions, from Figure 3 As can be seen, the absorbance of all test solutions increased significantly. This indicates that other cations significantly increased the absorbance of Fe. 3+ The selective recognition of ions was not interfered with; phenyl urea showed no interference with Fe. 3+ Ions have excellent specific recognition capabilities and can be applied to practical detection.

[0032] Example 4: Phenylacetylaminourea on Fe 3+ Quantitative testing

[0033] Identifying metal ions Fe 3+ The effect of concentration on probe performance is as follows: Figure 4 With Fe 3+ As the concentration in the test solution increases, the absorption peak at 289 nm gradually decreases.

[0034] Example 5: Kinetic Study of Phenylacetyl Urea

[0035] To verify whether phenylaminourea can be used in practical applications, the change in absorbance intensity of phenylaminourea over time during detection was studied at room temperature. Figure 5 As shown, phenyl urea (methanol:H2O = 5:5), 1×10 -4 The absorbance at 280 nm increased within 0–80 min (mol / L). The addition of Fe...3+ The absorbance intensity reached its peak between 0 and 5 minutes, and remained relatively stable between 5 and 80 minutes. This result indicates that the probe is effective for Fe... 3+ The test can be completed within 5 minutes and remain stable.

[0036] Example 6: Application Study of Phenylacetamide at Different pH Values

[0037] In addition, to investigate the practical application capabilities of phenylaminourea at different pH levels, the effects of phenylaminourea on different pH environments were explored. For example... Figure 6 As shown, the absorbance of phenylaminourea at 291 nm varies in the pH range of 4–6 under different pH conditions. The addition of Fe... 3+ Subsequently, it remained essentially stable at pH 4.0–6.0 and pH 8.0–12.0. Fe was added at pH 7. 3+ The absorbance intensity decreased significantly upon ionization. This result indicates that the probe can effectively identify Fe within different pH ranges. 3+ ion.

[0038] from Figure 7 It can be seen that using carbon-based solid acid as a catalyst improves the reaction yield, reduces the reaction time, and exhibits good catalytic activity. Furthermore, the recovery of the carbon-based solid acid after the reaction is simple and it can be directly reused. These results demonstrate that the catalyst preparation method used in this invention is simple and can be directly reused, giving the synthesis advantages such as low cost and environmental friendliness.

Claims

1. The application of a phenylaminourea in the preparation of an iron ion detection probe, characterized in that, Includes the following steps: 1) Prepare a test solution from phenylaminourea, wherein the structural formula of phenylaminourea is as follows: ； Preparation of the test solution: Step 1) First, take A mol of benzaldehyde and C mol of carbon-based solid acid and grind them in a mortar. Then add B mol of aminourea hydrochloride and continue grinding until the reaction is complete. During the grinding process, monitor the reaction progress by TLC. Step 2) After the reaction is complete, add a small amount of methanol to the reaction vessel, filter to remove the catalyst, and the catalyst can be recovered and reused more than 5 times; the filtrate can be distilled under reduced pressure to obtain phenyl urea. Step 3) Prepare a phenyl urea solution of a certain concentration to obtain the test solution; 2) Prepare a cation solution; 3) Mix the cation solution and the test solution to obtain the detection solution, and detect Fe by ultraviolet-visible absorption spectroscopy. 3+ The volume ratio of the cation solution to the test solution is 100:1; when the cation solution and the test solution are mixed, the concentration of the test solution is 1×10⁻⁶. -4 mol / L; the concentration of the cation solution is 1×10⁻⁶. -2 mol / L; 4) The tested solution contains Fe 3+ When ions are present, the absorbance of the solution system increases.

2. The application of the phenylaminourea according to claim 1 in the preparation of an iron ion detection probe, characterized in that, The process includes the following steps: loading an acid onto biomass and preparing a carbon-based solid acid catalyst using a one-step carbonization method, wherein the acid is p-toluenesulfonic acid, p-dodecylbenzenesulfonic acid, concentrated sulfuric acid, or chlorosulfonic acid.

3. The application of the phenylaminourea according to claim 1 in the preparation of an iron ion detection probe, characterized in that, The feed ratio of benzaldehyde, aminourea hydrochloride and carbon-based solid acid catalyst is (1-1.3):1:(0.05-0.2).

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