CN105136759A - Application of Copolymerized Column 5 Aromatics in Colorimetric Detection of Cetylpyridinium Chloride in CHCl3 System - Google Patents

Abstract

The invention discloses the application of copolymerization column 5 aromatic hydrocarbon detection in the colorimetric detection of cetylpyridinium chloride in a _CHCl3 system, and belongs to the technical field of compound detection. Specifically, the copolymerized column 5 aromatic hydrocarbons are made into the main solution with _CHCl3 ; the surfactants cetylpyridinium chloride, cetylpyridinium bromide, cetyltrimethylamine bromide, trimethylamine ethanol solution, _The CHCl solution of triethanolamine and sodium dodecylbenzenesulfonate is used as the guest solution; the guest solution is added to the above-mentioned host solution, if the fluorescence of the host solution is quenched, it means that the added guest solution is cetylpyridinium chloride ; If the fluorescence of the host solution does not change, it means that the guest solution is not cetylpyridinium chloride. The method for monitoring cetylpyridinium chloride has the characteristics of rapidity and high sensitivity, which opens up a new direction for the single selective detection of surfactants.

Description

Application of Copolymerized Column 5 Aromatics in Colorimetric Detection of Cetylpyridinium Chloride in CHCl3 System

technical field

The invention relates to a method for detecting cetylpyridinium chloride, a surfactant, in particular to a method for detecting cetylpyridinium chloride by using copolymerized column 5 aromatics, and belongs to the technical field of compound detection.

Background technique

Surfactants have a series of physical and chemical effects such as wetting or anti-adhesive, emulsification or demulsification, foaming or defoaming, solubilization, dispersion, washing, anti-corrosion, anti-static and corresponding practical applications, and become a flexible and diverse class. , Wide range of fine chemical products. In addition to being used as detergents in daily life, surfactants can be used in almost all fine chemical fields. Cetylpyridinium chloride is a cationic quaternary ammonium compound, and it is also a very important surface active and fungicide in life. Under the same use conditions, the killing rate of this product is better than that of dodecyl dimethyl benzyl ammonium chloride and dodecyl dimethyl benzyl bromide on heterotrophic bacteria, iron bacteria and sulfate unwilling bacteria Ammonium chloride and other commonly used quaternary ammonium fungicides. The feeding material adopts impact feeding, and the general use concentration is 20~80mL/L. However, higher levels of cetylpyridinium chloride are toxic. Therefore, the detection of cetylpyridinium chloride is a very important work. At present, for the detection of cetylpyridinium chloride, colorimetric detection is usually used, or a one-color-mass spectrometry method is used for determination. These detection methods require a long detection time, the detection is not obvious or it needs to be detected with the help of more complicated instruments.

Pillararenes, as a new class of macrocyclic molecules, have shown excellent results in host-guest chemistry. Many host-guest chemical systems have been well developed by modifying the structure of pillar arenes. It is well known that the copolymerized pillar 5-arene provides a good cavity structure, so the guest molecules with appropriate structure size can penetrate into its cavity to achieve the result of host-guest inclusion. Pyridine derivatives and traditional macrocyclic molecules such as crown ethers, cyclodextrins, and calixarenes construct host-guest inclusion complexes. Therefore, using this property of pillararene, it can be used as a new recognition system for the recognition of pyridine.

Contents of the invention

The purpose of the present invention is to provide the application of copolymerized pillar aromatics in _CHCl3 system for colorimetric detection of cetylpyridinium chloride according to the properties of pillar aromatics.

1. Preparation of Molecular Copolymerized Pillar 5 Aromatics

The preparation method of supramolecular copolymerization of pillar 5 arene of the present invention comprises the following process steps:

(1) Synthesis of intermediates: using ethanol as solvent, sodium hydroxide and potassium iodide as catalysts, under nitrogen protection, hydroquinone and hexadecane bromide at a molar ratio of 1:1~1:1.2 were refluxed for 20~ 24h, cooled, filtered off inorganic salts, evaporated to dryness under reduced pressure, dissolved in chloroform, extracted with distilled water, then dried with anhydrous sodium sulfate, and separated the organic phase with column chromatography to obtain an intermediate; the amount of sodium hydroxide was p-benzene 3 to 4 times the molar weight of diphenol; the amount of potassium iodide is 0.5 to 1 times that of p-bromododecane;

(2) Synthesis of copolymerized aromatic hydrocarbons: 1,2-dichloroethane as solvent, boron trifluoride diethyl ether as catalyst, paraformaldehyde, intermediates and p-xylylene dimethyl ether as raw materials, react at room temperature for 6~ 8h; then precipitated with methanol, dissolved in chloroform, extracted with distilled water, and the organic phase was separated by column chromatography to obtain copolymerized column 5 aromatic hydrocarbons. The dosage of p-xylylene dimethyl ether is 0.8~1 times of the molar weight of paraformaldehyde; the dosage of intermediate is 4~6 times of the molar weight of p-xylylene dimethyl ether; 0.5~1 times the molar weight.

The copolymerized pillar 5 arene is marked as DCP5-16, and its structural formula is as follows:

.

2. Application of Copolymerized Column 5 Aromatic Hydrocarbon Color Detection of Cetylpyridinium Chloride

1. Single fluorescence recognition of cetylpyridinium chloride (G) by copolymerized pillar 5 aromatics (DCP5-16)

Make DCP5-16 into 2×10 ^-3 mol/L main body solution with CHCl ₃ , the solution shows bright blue fluorescence under 365nm ultraviolet light; take 0.5mL main body solution in 7 colorimetric tubes, respectively Add 0.5 mL of different surfactants (cetylpyridinium chloride, cetylpyridinium bromide, cetyltrimethylamine bromide, trimethylamine ethanol solution, triethanolamine, sodium dodecylbenzenesulfonate ) in chloroform (concentration: 0.01mol/L), dilute to 5mL with DMSO, mix well and let stand. At this time, the concentration of DCP5-16 was 2×10 ^-4 mol/L. It was found that only the addition of cetylpyridinium chloride solution quenched the bright blue fluorescence of the main solution, while the addition of other surfactants did not change the fluorescence of the main solution (see Figure 1) . It shows that the copolymerized pillar 5 aromatics can colorimetrically detect the surfactant cetylpyridinium chloride in the CHCl ₃ system, so DCP5-16 can be used as a sensor molecule for monitoring the surfactant cetylpyridinium chloride.

2. Fluorescence titration of sensor molecules by cetylpyridinium chloride (G)

In order to further test the change of fluorescence intensity after adding guest molecules into the copolymerized pillar 5 arenes, we performed a fluorescence titration experiment. When guest molecules are added to the chloroform solution with a host concentration of 2×10 ^-4 mol/L, there is a strong fluorescence emission peak when no addition is made. With the increase of the concentration of guest molecules, the fluorescence intensity gradually weakens. Fluorescence quenching is achieved upon cetylpyridinium chloride (as shown in Figure 2). This weakening is due to the fact that the guest molecules of the electron-deficient system penetrate into the cavity of the electron-rich system’s copolymerized pillar 5-arene, so that the electron transfer leads to the fluorescence quenching of the host molecule, indicating that it can be realized by the “on-off” mode The host molecule performs spectroscopic detection of the guest molecule cetylpyridinium chloride.

3. Determination of the minimum detection limit of cetylpyridinium chloride by copolymerization column 5 aromatics

At 25°C, using fluorescence emission spectroscopy, in the titration experiment of copolymerized column 5 arene (2×10 ^-3 mol/L) to surfactant cetylpyridinium chloride (0.01mol/L), according to the added According to the volume and titration effect diagram of cetylpyridinium chloride, the minimum detection limit of the acceptor for cetylpyridinium chloride ion is 1.72×10 ^-8 mol/L (Figure 3), indicating that the copolymerization Pillar 5 aromatics have a high sensitivity for the recognition of cetylpyridinium chloride.

4. Measurement of fluorescence quenching time

The response time of copolymerized column 5 aromatics to surfactant cetylpyridinium chloride is shown in Figure 4. It can be seen from Figure 4 that after the surfactant cetylpyridinium chloride solution is dropped into the main solution, the fluorescence quenching is achieved within 5 seconds, indicating that the copolymerized pillar 5 aromatics can quickly identify the surfactant cetylpyridinium chloride. Hexaalkylpyridine.

3. Mechanism of recognition of surfactant cetylpyridinium chloride by copolymerization column 5 aromatics

As we all know, the copolymerized pillar 5-arene itself has a cavity structure, so guest molecules with suitable size and shape can be included in its cavity, and pyridine derivatives are often included in crown ethers, cyclodextrins, and calixarenes. In order to illustrate the mechanism of the recognition of the surfactant cetylpyridinium chloride by the copolymerized pillar 5 aromatics, we use one-dimensional NMR to illustrate this host-guest complexation process (see Figure 5). When one times the equivalent of the guest molecule (G) _is added to the host solution, H _a – He on the pyridine ring of the guest molecule and H _f closer to the N methylene group obviously move to the high field, which proves the inclusion process. Finish. Likewise, this inclusion process was also demonstrated by mass spectrometry to be 1:1 complexed (Fig. 6).

In order to prove the correlation between the subject and the object, we did a two-dimensional NMR NOSEY (see Figure 7). When the same molar amount of the host DCP5-16 and the guest G are tested, there is a strong correlation between H _a – H _f on the guest G and H ₁ – H ₄ on the host DCP5-16, indicating that the pyridine ring on the guest passes through the C– H···π interacts with cations···π to form a host-guest inclusion complex at a ratio of 1:1 to penetrate into the cavity of the copolymerized pillar 5 arene, which is consistent with the data measured by mass spectrometry.

A large number of experiments have shown that in the chloroform solution of acceptor molecules, the concentration of acceptor molecules is 2×10 ^-3 mol/L, and the copolymerized column 5 aromatic hydrocarbon sensor molecules to the surfactant cetylpyridinium chloride pass through a 1:1 network. The completion of the host-guest chemical process leads to the quenching of the host’s fluorescence. This weakening is due to the fact that the guest molecules of the electron-deficient system penetrate into the cavity of the electron-rich system’s copolymerized pillar 5 arenes, which makes the electron transfer lead to the fluorescence quenching of the host molecules. (as shown in Figure 8), to achieve specific recognition of the surfactant cetylpyridinium chloride. This approach opens up a new direction in the detection of surfactants by the molecular unicity of novel pillararene sensors.

Description of drawings

Figure 1 shows the specific fluorescence recognition of the surfactant cetylpyridinium chloride by the copolymerized column 5 aromatic hydrocarbon sensor.

Figure 2 is the fluorescence titration spectrum of the surfactant (cetylpyridinium chloride) on the copolymerized column 5 arene sensor molecules.

Fig. 3 is the determination spectrum of the minimum detection limit of cetylpyridinium chloride for copolymerized column 5 aromatics.

Fig. 4 is the response time of copolymerized column 5 arenes to surfactant cetylpyridinium chloride.

Figure 5 is a one-dimensional NMR assembly of copolymerized pillar 5-arene and cetylpyridinium chloride.

Fig. 6 is a mass spectrogram of the assembly of co-column 5 aromatics and cetylpyridinium chloride.

Figure 7 shows the two-dimensional NMR NOSEY assembled by co-column 5-arene and cetylpyridinium chloride.

Fig. 8 is a schematic diagram of the recognition mechanism of copolymerized pillar 5 aromatics and surfactant cetylpyridinium chloride.

Detailed ways

The preparation of the copolymerized pillar 5 aromatics and the method for detecting cetylpyridinium chloride of the present invention will be further described below through specific examples.

Example 1. Synthesis of copolymerized pillar 5 aromatics (compound DCP5-16)

1. Synthesis of intermediates: hydroquinone (4.4g, 40mmol), sodium hydroxide (10g, 4mmol), potassium iodide (4g, 24mmol), hexadecane bromide (26.8g, 88mmol) and ethanol (300.0 mL) into a 500mL round-bottomed flask, stirred and reacted for 3 days (72h), the solid precipitated out to obtain an intermediate. ¹ HNMR (400MHz, CDCl ₃ , 298K) δ (ppm): 6.82 (d, 4H), 3.96 (t, 4H), 1.75 (t, 4H), 1.43 (t, 4H), 1.26 (t, 48H), 0.86(s,6H).. The yield was 80%.

2. Synthesis of aromatics in copolymerization column 5: intermediate (2.79g, 5mmol), p-xylylene dimethyl ether (2.76g, 20mmol) were added to 80mL1,2-dichloroethane for dissolution; then paraformaldehyde (0.75 g, 25mmol), boron trifluoride diethyl ether (3.2mL, 25mmol) were added to the solution, and the reaction was stirred at room temperature for 8h. After the reaction, pour the solution into methanol to precipitate precipitates, filter, dissolve the precipitates with chloroform, extract with 30ml of distilled water x 3 times, dry, and separate the organic phase with column chromatography (petroleum ether/ethyl acetate=50:1v/v) to obtain White solid DCP5-12 (0.95 g), 18% yield.

Product DCP5-16: mp 126°C. ¹ H NMR (600MHz, chloroform– d ₃ ,293K)δ(ppm):6.81–6.78(d,10H),3.83(t,4H),3.77(s,10H),3.67(s,24H),1.78(t ,4H),1.33–1.15(m,52H),0.87-0.83(3,6H).The ¹³ CNMR(150MHz,chloroform–d,293K)δ(ppm):150.74,150.69,150.01,128.41,128.27,128.22 ,128.13,128.09,68.49,55.62,31.88,29.81,29.76,29.72,29.70,29.59,29.49,29.40,26.23,22.63,14.08.ESI-MSm/z:[M+NH ₄ ] ⁺ Calcdfor1188;Found,118 [M+Na] ⁺ 1193.8, [M+K] ⁺ 1209.7.

The synthetic formula of DCP5-12 is as follows:

Example 2: Recognition of Surfactant Cetylpyridinium Chloride by Copolymerizing Pillar 5 Aromatics (DCP5-16)

Make DCP5-16 a 2×10 ^-3 mol/L main solution with CHCl ₃ ; take 0.5 mL of the main solution in 7 colorimetric tubes. Prepare 0.5 mL of different surfactants (cetylpyridinium chloride, cetylpyridinium bromide, cetyltrimethylamine bromide, trimethylamine ethanol solution, triethanolamine, dodecylbenzenesulfonic acid Sodium) in chloroform (concentration: 0.01 mol/L) was used as the guest solution. Add the above-mentioned guest solution to the 7 colorimetric tubes, if the fluorescence of the main solution is quenched, it means that the added guest solution is cetylpyridinium chloride; if the fluorescence of the main solution does not change, it means that the guest solution is not chlorinated cetylpyridine.

Claims (10)

1. copolymerization post 5 aromatic hydrocarbons is at CHCl ₃the application of colorimetric detection cetylpyridinium chloride in system.

2. as claimed in claim 1 copolymerization post 5 aromatic hydrocarbons at CHCl ₃the application of colorimetric detection cetylpyridinium chloride in system, is characterized in that: by copolymerization post 5 aromatic hydrocarbons CHCl ₃be made into bulk solution; The CHCl of configuration surface activating agent cetylpyridinium chloride, brocide, cetrimonium bronmide, trimethylamine ethanolic solution, triethanolamine, neopelex respectively ₃solution is as object solution; Object solution is joined in aforementioned body solution, if the fluorescent quenching of bulk solution, then illustrates that adding object solution is cetylpyridinium chloride; If the fluorescence of bulk solution does not change, then illustrate that object solution is not cetylpyridinium chloride.

3. as claimed in claim 2 copolymerization post 5 aromatic hydrocarbons at CHCl ₃the application of colorimetric detection cetylpyridinium chloride in system, is characterized in that: the concentration of described bulk solution is higher than 2 × 10 ^-4mol/L.

4. as claimed in claim 2 copolymerization post 5 aromatic hydrocarbons at CHCl ₃the application of colorimetric detection cetylpyridinium chloride in system, is characterized in that: the concentration of described object solution is higher than 1.72 × 10 ^-8mol/L.

5. as described in claim 1 ~ 4 any one copolymerization post 5 aromatic hydrocarbons at CHCl ₃the application of colorimetric detection cetylpyridinium chloride in system, is characterized in that: the structure of described copolymerization post 5 aromatic hydrocarbons is:

。

6. as claimed in claim 5 copolymerization post 5 aromatic hydrocarbons at CHCl ₃the application of colorimetric detection cetylpyridinium chloride in system, is characterized in that: copolymerization post 5 aromatic hydrocarbons has following methods prepare and obtain:

(1) synthesis of intermediate: take ethanol as solvent, NaOH and potassium iodide are catalyzer, and under nitrogen protection, p-dihydroxy-benzene and bromohexadecane are with the mol ratio back flow reaction 20 ~ 24h of 1:1 ~ 1:1.2, cooling, suction filtration falls inorganic salts, the dry solvent of vacuum rotary steam, and chloroform dissolves, distilled water extracts, then use anhydrous sodium sulfate drying, organic phase pillar layer separation, obtains intermediate;

(2) synthesis of copolymerization post 5 aromatic hydrocarbons: with 1,2-ethylene dichloride for solvent, boron trifluoride diethyl etherate is catalyzer, and paraformaldehyde, intermediate, terephthaldehyde's ether are raw material, in room temperature reaction 3 ~ 4h; Then use methanol extraction, chloroform dissolves, and distilled water extracts, and then uses anhydrous sodium sulfate drying, organic phase pillar layer separation, obtains copolymerization post 5 aromatic hydrocarbons.

7. as claimed in claim 6 copolymerization post 5 aromatic hydrocarbons at CHCl ₃the application of colorimetric detection cetylpyridinium chloride in system, is characterized in that: in step (1), and the consumption of NaOH is 3 ~ 4 times of p-dihydroxy-benzene molar weight; The consumption of potassium iodide is 0.5 ~ 1 times to bromododecane.

8. as claimed in claim 6 copolymerization post 5 aromatic hydrocarbons at CHCl ₃the application of colorimetric detection cetylpyridinium chloride in system, is characterized in that: in step (2), and the consumption of terephthaldehyde's ether is 0.8 ~ 1 times of paraformaldehyde molar weight.

9. as claimed in claim 6 copolymerization post 5 aromatic hydrocarbons at CHCl ₃the application of colorimetric detection cetylpyridinium chloride in system, is characterized in that: in step (2), and the consumption of intermediate is 4 ~ 6 times of the molar weight of terephthaldehyde's ether.

10. as claimed in claim 6 copolymerization post 5 aromatic hydrocarbons at CHCl ₃the application of colorimetric detection cetylpyridinium chloride in system, is characterized in that: in step (2), and the consumption of catalyzer boron trifluoride diethyl etherate is 0.5 ~ 1 times of paraformaldehyde molar weight.