A kind of alkaline precision ph test paper that can be reused by washing and its preparation method and application

A reaction and aqueous solution technology, applied in the direction of material analysis by chemical reaction of materials, material analysis by observing the impact on chemical indicators, organic chemistry, etc., can solve the problems of gas atmosphere influence, pH test paper can not be recycled Achieve good reproducibility, intuitive and reliable test results, and strong tolerance

Active Publication Date: 2020-04-28
SHANDONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the test paper method is convenient and quick to detect pH, the commonly used pH test paper still has the disadvantages that it cannot be recycled and is easily affected by the laboratory gas atmosphere.

Method used

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  • A kind of alkaline precision ph test paper that can be reused by washing and its preparation method and application
  • A kind of alkaline precision ph test paper that can be reused by washing and its preparation method and application
  • A kind of alkaline precision ph test paper that can be reused by washing and its preparation method and application

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] Firstly synthesize 4’-p-hydroxyazophenyl-2,2’:6’2”-terpyridine, and add to 170ml CH 3 Add 5g of 2-acetylpyridine and 3.17g of p-nitrobenzaldehyde to OH, and add 15ml of 15% KOH aqueous solution and 160ml of NH while stirring. 4 OH, the system was stirred at room temperature for 3 days. The dark red precipitate was obtained by suction filtration, which was washed three times with distilled water and cold methanol respectively. The filtered solid was dissolved in ethyl acetate, and 1% NaHCO 3 After the aqueous two-phase extraction is performed once, the organic phase obtained is used anhydrous NaSO 4 Dry, CH 3 CH 2 Recrystallization from OH gave 4'-nitro-2,2':6'2"-terpyridine molecule with a yield of 34%.

[0043] The 4'-nitro-2,2':6'2”-terpyridine synthesized above and 0.46g of SnCl 2 1.536g was added to 12ml concentrated HCl and heated at 80°C for 8 hours. After cooling to room temperature, suction filtration to obtain residual solid powder, dissolve in ice water, use NaH...

Embodiment 2

[0047] The color change of the probe to alkaline.

[0048] Weigh 10.84mg of 4'-p-hydroxyazophenyl-2,2':6'2”-terpyridine synthesized in Example 1 and dissolve it in 20ml DMSO. After the solution is uniform and stable, pipette 1ml of the above solution Dilute to 50ml to obtain a pale yellow probe mother liquor.

[0049] Prepare 250ml 0.1mol / L NaOH aqueous solution, successively dilute and accurately quantify the pH 7-13 standard NaOH aqueous solution with the help of a pH meter, pipette 4ml probe mother liquor into multiple glass vials, pipette 67ul standard solutions of different pH Mix with the probe mother liquid, measure the UV-visible absorption curve of the detection liquid under different pH effects, and take pictures and record the color changes in different vials.

[0050] From figure 2 It can be seen from the UV-Vis absorption curve of mid-a, and OH - For the interacting probe molecules, the absorption peaks have a red shift from 372nm to 523nm, corresponding to the probe m...

Embodiment 3

[0052] The preparation process of the probe mother liquor is the same as in Example 2.

[0053] Configure NaBr, NaF, NaCl, NaH with a concentration of 0.012mol / L respectively 2 PO 4 , Na 2 HPO 4 , Na 3 PO 4 , Na 2 SO 4 For the aqueous solution, pipette 67ul of different salt solutions and mix with the mother liquor, measure the UV-Vis absorption curve of different detection solutions, and take pictures of the color changes in different vials.

[0054] From image 3 It can be seen from the UV-visible absorption curve of middle a that for different Brewster's base aqueous solutions that can dissociate hydroxide ions, the probe molecules can also respond, causing the absorption peak of the molecule to redshift from 372nm to 523nm. . The depth of the color change in the visible range is related to the dissociation constant of the salt solution, that is, the pH of the solution, where pka 3 Larger Na 3 PO 4 The solution is the most alkaline and the color change of the solution is the mos...

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Abstract

The invention relates to alkaline precise pH test paper reusable by water washing, a preparation method and an application thereof, belongs to the technical field of colorimetric analysis and detection, and provides a compound 4'-p-hydroxyazophenyl-2,2':6'2''-terpyridine shown in a formula I which is described in the specification, and a preparation method thereof. The preparation method comprisesthe following steps of: firstly preparing and obtaining 4'-nitro-2,2':6'2''-terpyridine, then using the 4'-nitro-2,2':6'2''-terpyridine to prepare and obtain 4'-amino-2,2':6'2''-terpyridine, and thenreacting with phenol to obtain 4'-p-hydroxyazophenyl-2,2':6'2''-terpyridine. The compound shown in the formula I is used as a probe molecule to prepare the alkaline precise pH test paper which can beused for detecting the change of an aqueous phase in the pH range 11-14.

Description

Technical field [0001] The invention belongs to the technical field of colorimetric analysis and detection, and specifically relates to an alkaline precise pH test paper that can be reused through water washing, and a preparation method and application thereof. Background technique [0002] pH is an important basic concept in electrochemistry and a widely used solution chemistry index. Because the definition includes the activity of a single ion, and the thermodynamic method can only measure the average activity of the electrolyte (that is, the average activity of positive and negative ions), it is not a physical quantity that can be directly measured. In solution chemistry, as an important indicator for detecting the pH of a solution, pH often requires a fixed detection standard and the support of galvanic cell electrodes based on potentiometric analysis. The appearance of pH test paper provides a more convenient and intuitive idea for pH detection. In the 17th century, the Br...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D213/42G01N21/80
CPCC07D213/42G01N21/80
Inventor 郝京诚董川
Owner SHANDONG UNIV
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