A simple kitchen science experiment was designed to prepare carbon quantum dots using kitchen waste as raw materials, avoiding the hydrothermal method which is currently widely used in laboratories. The experiment requires common kitchen appliances, utensils, and waste material like fruit peelings that are typically discarded; this experiment provides a safe way for kids to prepare carbon quantum dots at home under adult supervision. It can also be carried out for high school students and undergraduates, encouraging them to learn key concepts about carbon quantum dots by introducing related instrumentation as well as understand the applicability of such dots toward the detection of heavy metal ions. Through such experiments, we attempt to engage students in cutting-edge research through fun, simple and frugal kitchen science experiments and aim to refute the rumors of "quantum + life".

Applying scientific-issue-oriented education, the green synthetic process of 2-nitrobenzaldehyde was modified and applied as a fundamental organic experiment for oxidation reactions in undergraduate education. Selective oxidation of 2-nitrobenzyl alcohol was achieved in the presence of 0.1 mol% water-soluble 2-(1-hydroxy-2, 2, 6, 6-tetramethylpiperidin-4-ylidene) acetic acid (TEMPO-COOH) and commercially available NaClO. The corresponding 2-nitrobenzaldehyde was obtained in 93% yield and > 99% purity. This newly designed experiment includes a series of basic organic experimentation techniques and the entire classic organic synthesis process, including reaction monitor, structure characterization, purity analysis and so on. Furthermore, the principle of green chemistry and the general way of methodology study in organic chemistry were integrated. Environmentally friendly and inexpensive starting materials, as well as the 3‒4 h experiment period, make this innovative experiment suitable for undergraduate education. Based on the experimental design, the corresponding micro-lecture concerning advances in oxidation was developed and incorporated into the education program. Thus, the collaboration of theoretical study and practical operation was achieved, improving the ability of undergraduates to solve complicated issues in organic synthesis and achieving high training quality.

The classical basic chemistry experiment "determination of micro-quantitative fluorine in water with ion-selective electrode method" was improved to "determination of fluorine content in tea and tea water with ion-selective electrode method". The experimental contents for the "determination of fluorine in tap water" were extended to the "determination of fluorine in tea and tea water, fluorine leaching rate of tea leaves." The effects of tea : water ratio, temperature, brewing time, and tea powder size on the fluorine leaching rate of tea leaves were also investigated. The fluoride content in five kinds of representative tea samples showed that drinking dark tea caused the risk of excessive fluoride intake. In addition, the experiment was further expanded and extended to the ion selective electrode method and other detection methods of trace fluoride. The introduction of research content and grouping experiments was more beneficial to cultivate students' scientific research thinking and spirit of unity and cooperation. Exploratory and challenging experimental contents improved students' ability to innovate and solve practical problems. The infiltration of tea and general health knowledge in students' lives, enhanced their health consciousness. This experiment was rich in content, interesting, easy to operate and promote, and thus suitable for junior undergraduates.

The design of this experiment includes the synthesis of Fe(Ⅱ) spin crossover compounds and the study of thermochromic properties. The effects of temperature and solvent on the spin state of the complex are explored. Thermochromic composite polymers with certain processability are prepared and characterized by various methods. From the verification of basic principles to the design of modified practical materials, the experiment involves multiple disciplines such as inorganic chemistry, analytical chemistry, polymer science and materials science. Through the entire synthesis process, characterization, property regulation, and application, students' knowledge, skills, and accomplishments are fully trained.

The preparation of potassium sulfate using a two-step method is an important method for the large-scale production of potassium fertilizer. Our experiment uses it as a reference, taking the basic knowledge of the quaternary phase diagram as the theoretical guideline, and covers the relevant knowledge of inorganic double decomposition reactions and element ion analysis detection. In this study, we use a combination of testing methods including traditional titration, spectrophotometry, and ICP atomic emission. This promotes basic operational knowledge and theory, as well as a combination of traditional and modern instrumental analysis. The experiment has many advantages, such as easily obtainable materials, easy operation, obvious phenomena, and green environmental protection. It can be used in modular teaching and divided into multiple experimental links to meet the requirements of different students. The operation of the experiment can not only make students realize the important role of chemistry in social production but also cultivate their basic operational ability and improve their basic practice and innovation ability.

Biological sulfhydryl detection and protein labeling are critical in current scientific research. In this study, the traditional Ellman method and the newly developed Naph-EA-Mal fluorescent probe were used to quantify sulfhydryl groups in bovine serum albumin, thus giving students a better understanding of both traditional methods and cutting-edge technology. The content of sulfhydryl can be detected in situ through measuring the fluorescence intensity. In addition, students gain knowledge regarding the mechanism of thiol probes and the influence of the protein's three-dimensional structure on the reactivity of the sulfhydryl groups within the protein. The experiment covers basic technology of treating cells and different methods of treating biomacromolecules. These methods are comprehensive, modularized, and easy to implement. This lab course will help students obtain cutting-edge chemical biology knowledge. In addition, the experiments on the virtual experiment platform could further help students learn and understand the principles and operational methods used in this experiment.

The preparation of CeO₂-based catalysts has been transformed to a comprehensive experiment for undergraduates based on its existing innovative achievements toward environmental protection. In the transformation, the effect of preparation conditions (such as precipitation pH, precipitation agent, filtration method, and different Ce/Zr ratio) on the performance of the catalysts was investigated. The results indicated that Ce_0.75Zr_0.25O₂, prepared by a simple co-precipitation method with sodium carbonate as an environmentally friendly precipitant and at pH 8–10, exhibited excellent activity; its pollutant conversion efficiency reached up to 95%. This experimental study combines the cutting-edge technology with classic experiments, to promote a teaching concept that allows the integration of science, education, and innovative developments. To achieve pollution control through strategies based on science and technology, this experimental study was conducive to improving students' awareness of environmental protection and resource strategy. As a result, students significantly benefited from this new experiment by enhancing their social responsibility and national pride.

The wettability of the solid surface is related to its microgeometry and physicochemical properties, which is determined by both the specific micro-geometry structure of the surface and the physicochemical properties of surface chemicals. The wettability is an important feature of the solid surface and can be measured quantitatively by the contact angle. It not only directly affects life activities of both animals and plants in nature, but also plays an important role in both human's daily life and industrial and agricultural production. The wettability of a solid surface can be measured by the contact angle of water. This popular science experiment discusses the superhydrophobic surface of lotus leaf, water strider and other living things, and expounds the principle of superhydrophobicity, so as to help people understand the origin and development of superhydrophobic materials in life. The superhydrophobic material was prepared by sol-gel method, and its superhydrophobic property was compared with the control surface. Finally, we carried out "traffic light" experiment by employing indigo carmine on the superhydrophobic material for people to feel the beauty and interest of chemistry, so as to stimulate their interest in chemistry, and further lead people to explore and think about the material science.

Sample preparation is a critical step for target detection. However, the traditional sample preparation techniques usually experience limitations, including time-consuming and tedious workflows and environmentally harmful processes that give rise to secondary pollution. Solid-phase microextraction (SPME) technology integrates sampling, extraction, concentration, and sample injection into one step. It does not require organic solvents during the extraction process and is considered as a simple, fast, and environment-friendly sample pretreatment technique. In this study, SPME technology was used to extract BTEX from water samples. The SPME conditions were carefully optimized, and a BTEX quantitative detection method was established through coupling the SPME with gas chromatography-mass spectrometry (GC-MS). The results showed that this new SPME method possessed excellent linear ranges of 100–10000 ng·L^-1 for benzene, toluene, ethylbenzene, and xylene, detection limits of 37.50, 16.67, 45.45 and 10.64 ng·L^-1, respectively and linear correlation coefficients (R²) all higher than 0.99. Finally, the established SPME method was applied to real water samples for BTEX detection, obtaining recoveries of 86.83%–114.8%. The entire SPME workflow is simple and highly efficient, and the detection results are reliable. This work introduces the advanced SPME technology into undergraduate teaching experiments, thus incorporating ideological and political elements to lay the groundwork for green environmental protection for students. Furthermore, this experiment helps students learn advanced sample pretreatment technology and experience how the cutting-edge technology triggers revolutionary innovations within the field of analytical chemistry.

In the current experiment for barium content determination by using the precipitation gravimetric method, the precipitation aging process is found to be time consuming. Depending on the thermodynamic theory of crystal precipitation growth, the microwave technology is innovatively introduced to shorten the precipitation aging process through an improved experiment. Kinetic analysis reveals that crystal nucleus formation is governed by two factors: nucleus formation rate and growth. After response surface method optimization, two consecutive microwave irradiation cycles are conducted for 5 min at 300 W; the standing interval is 15 min. Finally, a coarse BaSO₄ precipitate with a complete morphology and large particle size distribution (~10 μm) can be successfully prepared. The total time for the precipitation aging process through this improved experiment is only 25 min. The sufficient integration between the metaphysical principles and basic experimental teaching by various visual micro-representation techniques will help to enhance the frontier and high-order characteristic of undergraduate experimental teaching. From the experimental teaching perspective (4 class hours), the improved experiment is more in line with modern chemistry experiment teaching and lays a good foundation for students' scientific research and innovation abilities.

Sulfur emission from fossil fuel combustion can lead to acid rain; thus, it is essential to reduce the sulfur content of fuel through deep desulfurization. The polyoxometalate (POM)-based covalent organic framework (COF) is considered an excellent catalytic material because it exhibits excellent redox activity, adjustable hydrophilicity, and good recyclability. The successful encapsulation of vanadium-containing POM ((NH₄)₅H₆PMo₄V₈O₄₀, PMo₄V₈) into EB-COF (EB represents ethidium bromide) is achieved via ion exchange, and a new composite of PMo₄V₈@EB-COF is produced. The composite structure is determined through X-ray diffraction analysis, infrared spectroscopy, and elemental analysis. The oxidative desulfurization potential of PMo₄V₈@EB-COF is studied using dibenzothiophene as a model fuel and oxygen as an oxidizer. The catalytic results show that PMo₄V₈@EB-COF exhibits an excellent desulfurization performance. At 100 ℃, dibenzothiophene (DBT) conversion reaches 96.6% after the reaction for 2.5 h. In this experiment, chemistry knowledge of various subjects as well as concepts of synthesis chemistry and green chemistry are involved. Moreover, this experiment is suitable for modular teaching with individual sections to meet experimental teaching needs. Through this experiment, students can cultivate the spirit of innovation and improve comprehension abilities.

The preparation of [Co(II)Salen] complexes and oxygen-carrying experiments are listed as a comprehensive chemistry experiment by many universities. Owing to the drawbacks of the existing experimental equipment, innovative designs and improvements were made as discussed in this paper. The designed device ensured the gas was distributed stably using a steady-pressure and steady-airstream, allowed multi-group experiments to be carried out simultaneously and independently, and improved the success rate of the experiment considerably. A new oxygen-carrying device, in which three-way and two-way valves were installed in parallel, was designed and assembled. The residual air was discharged from the U-shaped tube through oxygen blowing so that the volume of oxygen absorption could be measured more scientifically and accurately. Simultaneously, the oxygen-carrying device was fixed on a steel plate, and the key components were all made of the steel, which significantly improved the air tightness and service life of the instrument.

Shape memory polyimide (SMPI) as a smart material has attracted remarkable attention in high-tech fields such as aerospace and intelligent photoelectricity due to its shape memory effect and work capability at high temperatures. By designing the simple and effective device to obtain water-free and oxygen-free conditions, the polyamic acid (PAA) precursor is produced from polycondensation of 1, 3-bis(3-aminophenoxy)benzene and 4, 4'-oxydiphthalic anhydride, and then PAA is converted into SMPI via step-wise thermal curing. SMPI was characterized using gel permeation chromatography, infrared spectrometry, dynamic mechanical analysis, and thermogravimetric analysis. SMPI exhibits excellent shape memory effects and good work capability, indicated by overturning a metal sheet 11.93 times higher than its own weight. This highly comprehensive experiment incorporates polymer synthesis, product characterization, mechanical property testing, and applications. Due to stable experimental phenomena and reproducible results, this experiment is suitable for undergraduate teaching. Through simulating the deployable process of red flag in Tianwen-1, this experiment can stimulate scientific interest, cultivate innovative thinking, and enhance students' comprehension. It can also make students appreciate the unique style of aerospace in China and enhance national pride.

Polypyrrole, a π-conjugated conducting polymer with specific photoelectric properties, has been systematically introduced into the curricula of many colleges. Its preparation has been used to illustrate comprehensive experiments, integrating knowledge from multiple disciplines such as chemistry, physics, and material science. The Electrochemical Preparation Experiment of Polypyrrole developed by our university was successfully advanced from a simple preparation task into a comprehensive open experiment. First, electrochemical polymerization was carried out under the three-electrode system and the polymerization conditions were explored. Thereafter, a cyclic voltammetry test was conducted to study the electrochromism of polypyrrole. Finally, the conductivity of the products, obtained under different conditions, was characterized and analyzed. The enhanced content of this new experiment design will help students improve their comprehensive skills and cultivate their scientific thinking, which conforms with current developments in modern chemistry education.

Photochemical reactions are ubiquitous in our daily life. The cyanotype is a typical application of photochemical reactions to promote social development; it is generally well received due to its indefectible blue color. We have designed a popular science experiment program for three different age groups based on the photochemical reaction characteristics of the cyanotype. This program launches popular science content contrapuntally and includes making cyanotype photos, explaining the concept and principles of photochemical reactions, and carrying out UV protection experiments. To enhance the connection with life, we also creatively expanded the cyanotype-ultraviolet experiment to intuitively show participants the principles and effects of ultraviolet light. These experiments are easy to operate, safe, and environmentally friendly. In addition, the experimental results are very attractive, ornamental, and artistic, and are easy to understand, accept, and participate in. At the same time, they can stimulate participants' interest in learning chemistry and describe how chemistry can improve life.

This work provides an open comprehensive experiment, which introduces green electrochemical technology into laboratory teaching. Through electrooxidative cross-coupling, highly para-selective amination of aromatic amines was achieved, and the reaction mechanism was explored using cyclic voltammetry. The oxidative C—N amination reaction was conducted at room temperature under constant current and worked well in the presence of air. Firstly, current, quantity of electric charge, and electrolytes were measured with phenothiazine and N, N-dimethylaniline as template substrates. After determining the optimal conditions, the scope of aromatic amines was studied, and the reaction mechanism was explored using cyclic voltammetry. Experiments adapted from scientific research, such as this, can stimulate both innovative thinking and innovation consciousness in undergraduate students.

Chromic materials are widely used in aerospace, energy and chemical industries, food, national defense, and scientific research. Viologen compounds (N-substituted 4,4’-bipyridine quaternary ammonium salts) are an important class of chromic materials that exhibit rich chromic properties under external stimuli, such as light, electricity, and temperature. This innovative fundamental chemistry experiment was designed based on scientific frontier results of viologen compounds. The o-hydroxyacetophenone substituted viologen was synthesized, and its solvatochromism, thermochromism, and reversible NH₃ vapor sensor in the solid state were studied, aiming to stimulate students’ curiosity and desire for exploration, cultivate students’ interest in chemistry, broaden their horizons, and improve their chemistry cognition. The raw materials for this experiment are simple and easy to obtain, the synthesis method is simple, and the reaction time is short with high yield and good repeatability. All chromic phenomena are fast, highly sensitive, and can be directly observed with the naked eye, which aids the application of these experiments.

Selectivity is a core organic chemistry concept and is often a key issue in organic chemistry research. In this experiment, (R)-(−)-carvone was used as a substrate upon which two oxidation methods were employed to selectively give two different products. The epoxidation of the two double bonds of carvone shows chemoselectivity, while whether the corresponding product is a mixture of isomers shows stereoselectivity. Since this experiment features inexpensive reagents, simple operation and workup procedures, and high yields, it is suitable for organic chemistry experimental teaching, deepening undergraduates' understanding of chemoselectivity and stereoselectivity.

Enantiomerism, which is a fundamental concept in organic chemistry, is challenging for many undergraduate students. In current laboratory teaching books, asymmetric syntheses are very limited. Particularly, there are few experimental cases for the synthesis of enantiomers via asymmetric catalysis. We rationally designed a comprehensive experiment for the asymmetric catalysis based on a scientific report for use in teaching chemistry experiments. An optically active α-amino ketone is prepared using a chiral Brønsted-acid-catalyzed three-component asymmetric reductive amination reaction of aniline, 2, 3-butanedione, and benzothiazoline. To emphasize the influence of catalysts on the enantioselectivity of product, chiral Brønsted acids with different configurations and steric groups are introduced as catalysts. The target chiral products will then be analyzed using NMR, chiral HPLC, and polarimetry. This experiment effectively upgrades the current popular two-component, achiral synthesis to a multi-component, chiral synthesis. Results indicate that this experiment has good repeatability, is sufficiently challenging, and promotes exploration and innovation. Implementation of this project will benefit students in learning how to manipulate a multi-component reaction, further understand complicated reaction mechanisms, investigate the factors which influence stereoselectivity, and learn how to carry out an innovative experiment.

Currently, university-level analytical chemistry experiments are relatively simple, which impacts the students' ability to learn quality assurance and quality control techniques for the entire analysis process, and reduces the cultivation of exploration skills and quality of comprehension. Therefore, we designed a comprehensive analytical chemistry experiment which involves sample preparation, method validation, sample pre-treatment, quantitative analysis, and data processing, as well as methods for quality assurance and quality control during the execution of experiments. In this experiment, students were instructed to accurately determine the cadmium content in a rice sample using graphite furnace atomic absorption spectrometry. This experiment is based on an external standard quantitative method, and various quality assurance and quality control methods were used in the analysis process. This comprehensive experiment involves the entire analysis process, which not only helps our students to apply theory to practice, but also helps develop students' problem solving abilities and their thinking abilities. This experiment is easy and safe to operate and can be completed within 8 h. Furthermore, analytical chemistry teaching and research groups in universities may use this as a project for sophomore or junior students.

The typical aggregation-induced emission (AIE) property of tetraphenylethylene and its derivatives has been widely reported, leading to broad applications in OLED, fluorescent probes, and biochemical imaging. Due to advanced achievements, an AIE-related comprehensive experiment for undergraduates would encourage them to pursue scientific studies. In the original experiment, tetraphenylethylene (TPE) was synthesized using the McMurry coupling reaction, which takes 8 h to complete. In our modified experiment, using ultrasonic assistance, the synthesis was shortened to 2 h. We have added two parallel control complexes, methoxyl-(TPE-OMe) and bromide-derivatives (TPE-Br), with the push or pull electro effects, to observe UV-Vis absorption, fluorescence emission, and redox potential. The student can understand the chemical principle of red- and blue-shifts of maximum emissions by directly observing them with TPE and its derivative. Compared to the original experiment, our modified experiment made significant improvements, such as introducing parallel experiments to promote scientific thought and ultrasonic-assisted synthesis to shorten the synthesis, making the experiment more innovative, environmental-friendly, and efficient.

The selective reduction of nitro groups, selective protection of hydroxylamine, and the [3, 3]-σ rearrangement are fundamental reactions in organic chemistry. This experiment systematically incorporates three basic reactions into a compact, one-pot chemical transformation in 3.5 h. The reaction occurs abundantly, and can be easily monitored by thin-layer chromatography. High value-added functionalized o-aminophenol derivatives could be obtained from simple nitro arenes in one pot. In addition, the three-step reaction can be run separately with high yields. The final product can be purified using silica gel column chromatography, and the structure can be determined via high-resolution mass spectrometry and nuclear magnetic resonance spectroscopy. This reaction is based on fundamental organic chemistry concepts. It is important for undergraduates to learn functional group transformations and develop the ability to observe various experimental phenomena. Moreover, the reaction has high efficiency in a short time and may have a wide range of applications in the preparation of functional o-aminophenol derivatives.

The Suzuki-Miyaura coupling reaction for the synthesis of biphenyl compounds through aryl halides and aryl boronic acids has been widely used in the synthesis of natural products, drugs, and functional materials. However, there are very few relevant experiments currently in undergraduate teaching, mainly because the traditional Suzuki reaction conditions involve expensive ligand-containing Pd catalysts. Furthermore, most reaction solvents contain toxic solvents such as toluene or 1, 4-dioxane, and the reaction requires an inert gas atmosphere and heating for over 8 h. These restrictions largely prevent undergraduates from carrying out this important organic chemistry experiment. In this study, the Suzuki coupling conditions were modified as follows: ligand-free Pd/C was used as the catalyst, ethanol mixed with water was used as the reaction solvent, and then the reaction was stirred at room temperature for 30 min in the open air (oxygen) instead of in an inert atmosphere. Under these conditions, the starting materials, phenylboronic acid and 4-bromobenzoic acid, were reacted using potassium carbonate as the base, which efficiently synthesized 4-bibenzoic acid. Compared to the traditional Suzuki reaction conditions in which the catalyst cannot be recovered, the Pd/C catalyst recovered in this experiment can be recycled more than 5 times without substantial activity loss. This experiment provides the possibility for undergraduates to become familiar with the Suzuki reaction due to improvements in cost, operability, and environmental protection.

Miniemulsion polymerization technology has several advantages, including simple operation, use of green technology, and a wide range of applications, and can be used for innovative experimental teaching for undergraduates. By introducing spiropyran derivatives with photochromic properties into the miniemulsion polymerization, the prepared colloidal particles have apparent photochromic and photoswitchable fluorescent properties, which may further stimulate students' interest in experiments and foster a sense of closeness to scientific research. In this paper, a one-step miniemulsion polymerization method was used to prepare photochromic colloidal particles containing spiropyran derivatives, that's 2-(3', 3'-dimethyl-6-nitrospiro[chromene-2, 2'-indolin]-1'-yl)ethyl methacrylate (SPMA), at 75 ℃ for 3 h. The particle size and spectra of the colloidal particles were measured using a laser particle size analyzer, UV-Vis absorption spectrometer, and fluorescence spectrometer. The results show that the particle size of the prepared colloidal particles is approximately 60 nm, and they exhibit obvious photochromic and photoswitchable fluorescent properties under ultraviolet and visible light. Preliminary studies show they have valuable fluorescent anti-counterfeiting applications.

Three zinc benzimidazolate frameworks with different topological network structures, sql, SOD, and RHO, were prepared using different solvents and templates. Encapsulation of perylene in these three metal-azolate frameworks was explored to prepare novel porous materials with unique luminescent and fluorescent sensing properties. Product purities were determined using powder X-ray diffraction, and the luminescent properties were analyzed via fluorescence spectrometry. The loading amount of perylene was determined using UV-Vis spectroscopy. Advantages of this experimental design include a simple synthesis, high success rate, short reaction time, mild reaction conditions, and environmentally friendly by-products, indicating high feasibility as a teaching experiment for undergraduates. Through the preparation, characterization, and application of metal-azolate framework materials, students can easily understand coordination chemistry synthesis and porous material characteristics. Additionally, the combination of the synthesis of porous framework materials and the packaging of fluorescent molecules may make the experiment more interesting and inspire students to explore material performance and applications.

A new and comprehensive experiment for the preparation of safety and environmental protection materials was designed to meet the demand of the 14th Five-Year Plan (2021–2025) to train talents in higher education, promote the all-round development of students, strengthen the promotion of interdisciplinary subjects, and overcome the shortcomings of intuition, intersectionality, practice and innovation in traditional teaching experiments. A flame retardant (BMP) was synthesized, based on the reactivity of the P—H bond in the 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) structure by addition reaction with diphenylmethane bismaleimide (BMI). Thereafter, according to the principle of epoxy ring-opening and polymerization reactions, epoxy resin could be cured using a hardener. Additionally, the flame retardant epoxy resin was prepared by uniformly dispersing BMP into an epoxy resin before curing, using the melt blending method. The experiment not only combines basic knowledge with that on the scientific frontier but also links synthetic experimentation with practical application to cultivate the ability of students to find and solve problems, acquire new knowledge, and integrate theory with practice.

Coumarin structures are commonly found in many functional molecules. Although conspicuous progress has been made to synthesize coumarin derivatives, these approaches are often limited by harsh reaction conditions, low functional group tolerances, and environmentally harmful processes. The frontier synthesis method has been applied in this experimental design. The coumarin framework was accessed through two steps in the one-pot approach: E → Z isomerization of cinnamic acid visible-light and subsequent C(sp²)-H oxidative cyclization, using vitamin B2 as the photocatalyst. The reaction was characterized by mild conditions, inexpensive starting materials and reagents, atom economy, and environmentally friendly processes. The reaction was conducted in large-scale by using a customized continuous flow device based on the photocatalyzed gaseous reaction. This experimental design augments organic experimental teaching of semi-micro-scale reactions, continuous flow synthesis, photoreactions, biomimetic catalysis, green chemistry, radical processes, and computational chemistry. In addition, it also plays an important role in helping undergraduate students to gain in-depth understanding of basic organic chemistry, master experimental skills, and develop an interest in organic chemistry. Finally, a spectrophotometric method for quantitative analysis of various coumarin derivatives was also explored based on the chromogenic reactions of metal complexes. It is easy to popularize this teaching model for multi-disciplinary experiments.

Synthesis and investigation of the chemiluminescence of Luminol is a valuable educational and pedagogical tool. In recent years, a few domestic universities started offering this experiment to undergraduate students. To further enrich the scientific and theoretical understanding of the synthetic and chemiluminescent process, we have improved the existing experiments in several ways. First, we introduced mechanical stirring, sulfur-mediated reduction, and microwave chemistry in the synthesis portion to achieve safe, rapid, and efficient preparation of high purity Luminol. Second, we introduced the Luminol/H₂O₂/SCN⁻/Cu²⁺/OH⁻ system for chemiluminescence oscillation, which involves applying important concepts such as kinetics, autocatalysis, non-equilibrium thermodynamics, and dissipative structures. Finally, to achieve real-time quantitative monitoring of the light intensity and frequency of the chemiluminescence oscillating process, we designed a simple miniature magnetic stirring heating device, which can be used in conjunction with a fluorescence spectrometer. Students can design comparison experiments independently and explore the mechanism. This experiment involves combining several important multidisciplinary chemical concepts. The precise measurement of the chemiluminescence oscillating process has effectively captured the interest of students.

Advanced Physical Chemistry Lab is a mandatory course for undergraduate students majored in chemistry at our university, in which the preparation and characterization of catalysts is an indispensable part. This study improves upon the original "The Analysis of the Acid Property of Materials by NH₃-TPD Method" and "Measurement of Catalytic Activity and Selectivity of the Catalyst" experiments. The original experiments involve the effect of reaction temperatures and reaction times on the catalytic activity and selectivity of a single catalyst, as well as the principles of NH₃-TPD methods and the measurement of the acidic properties of materials. Conversely, the improved experiment focuses on the connection between the acidic properties and pore structure of the catalytic performance by comparing the catalytic performance of three different catalysts under the same reaction conditions. In addition, the improved experiment takes advantages of the results of the N₂ physical adsorption experiment, so that students can comprehensively understand the preparation, modification, and characterization technology of catalysts and have a clearer understanding of the factors affecting the catalytic performance of catalysts. The purpose is to enable students to integrate the theoretical knowledge in related courses and have a deeper understanding of the principle of zeolite β, which plays a catalytic role in the transformation of large reactants.

In order to introduce the concept of visualized experiment into basic laboratory teaching and to enhance the exercise on esterification, comprehensive improvement was made on the preparation of ethyl acetate. In this experiment, acetic acid reacts with ethanol to produce ethyl acetate in the presence of sodium bisulfate and allochroic silica gel, and the endpoint of the reaction is vidually indicated by methyl violet discoloration. This design of the reaction circumvents the problems of limited reagents and carbonization. The conversion was measured by gas chromatography, and the result showed that acetic acid was almost completely turned into the target product; the structure of the product was confirmed by ¹H NMR. This experiment allows students to have a feel of the dynamic process of esterification by the discoloration of methyl violet with the increased acidity of the reaction system. Consequently, it can enhance students' interests in learning organic chemistry, enliven their thinking and improve their study efficiency.

Some colors in nature are structural colors with very fine structures at the micrometer or nanometer scale. These structural colors are usually shiny and change with the angle of view, such as the color of butterflies' wings, the color of birds' feathers, the surface of sea shell and beetle, etc. Due to the advantages of fastness, environmental friendliness, and iridescent effect, structural color has a broad application prospect in display, decoration and anti-counterfeiting fields. In this experiment, a green and simple method was used to obtain the monodisperse silica nanoparticles by simply mixing cheap and readily available ethyl orthosilicate with ammonia hydroxide. By changing the ethyl orthosilicate to ammonia hydroxide ratio, the particle size of silica nanoparticles can be tuned, so that suspension inks with different structural colors can be obtained. The resulted silica nanoparticles can be directly used for writing or drawing structural color patterns, and are expected to be used in low-cost color pigment preparation.

Organic Synthesis Experiment is an important independent experimental course for chemistry students. Current organic synthesis experiments are mostly single-step synthesis, which are insufficient for students' training on connection of multi-step syntheses, compound detection, and identification. Synthesis of ethyl 7-nitrobenzothiophene-2-carboxylate is a comprehensive project in the Organic Synthesis Experiment course for students majoring in applied chemistry at our school; however, it suffers from long reaction times, low yields, difficult work-up, and toxic reagents. This project aims to improve the synthesis methods and procedures of the benzothiophene ring system by reducing the amounts of reagents, increasing the yield, and optimizing the work-up processes. This improved experiment is more suitable as a teaching experiment. Organic spectroscopy was also added in the improved experiment so that students can learn how to characterize target compounds through infrared spectroscopy, nuclear magnetic resonance, and mass spectrometry, which will improve students' comprehension and quality of learning.

A 6-class comprehensive chemistry experiment was designed to introduce the research hotspot of photochromism, aiming to impart the organic synthesis, spectral analysis, and other related knowledge to students. In this experiment, the rhodamine 6G hydrazide salicylaldehyde Schiff base was synthesized through two steps. This molecule was then combined with zinc ion to obtain the rhodamine 6G hydrazide salicylaldehyde Schiff base zinc ion complex, which exhibits photochromic property. Students can learn about photochromic phenomena by observing the color and UV spectrum changes in the complex before and after UV light irradiation, both in solution and in solid substrates. This, combined with classroom instructions and literature reading, allows students to understand the mechanism of photochromism. The reagents and instruments required for this experiment are simple and cost-effective, which makes the experiment suitable for undergraduate chemistry experiments or other related majors. In addition, these experimental phenomena are notable and interesting. Through this experiment, students can not only improve their knowledge and professional qualities but also cultivate their interest and love for chemistry.

Oxidation of alcohols is an important method to produce aldehydes and ketones, and is an important component in organic chemistry theory and practical teaching. Currently, oxidation of cyclohexanol to cyclohexanone is commonly introduced in practical undergraduate textbooks. The only experiment designed for the preparation of aldehydes from primary alcohols in current practical textbooks is using the oxidant H₂O₂ for the selective oxidation of benzyl alcohol to benzaldehyde at 90 ℃ in the presence of a catalytic amount of Na₂WO₄·2H₂O/(C₄H₉)₄NHSO₄. However, this reaction has low-yields, potential safety issues, and concerns with environmental pollution. Here, we present a practical alternative reaction involving the mixed catalytic system of Fe(NO₃)₃·9H₂O, 4-hydroxy-2, 2, 6, 6-tetramethyl-piperidinooxy (4-OH-TEMPO), and acetic acid (HOAc). This reaction allowed for a highly selective oxidation of benzyl alcohol to benzaldehyde with an isolated yield of up to 91% using O₂ as the oxidant and H₂O as the solvent under mild conditions. This new strategy for the selective oxidation of primary alcohols is a low-cost, and more importantly, highly efficient and green strategy. Additionally, several techniques such as thin layer chromatography, gas chromatography, flash preparative liquid chromatography, and ¹H NMR spectroscopy were used to detect and purify products, to improve experimental techniques, and to enhance the scientific literacy of undergraduate students.

Upon dissolution of ammonia in water, an instant imbalance of atmospheric pressure inside and outside the bottle is produced. This imbalance allows the fountain experiment to be carried out based on the preparation, collection of ammonia gas, and the tail gas treatment device. Through a simple experiment, a double-fluorescent fountain can be formed based on the Luminol reaction and the indicator phenolphthalein. The purpose of this experiment is to demonstrate the properties of ammonia and show Luminol's bright blue light reaction when it encounters blood. This reaction is mainly used in the detection of blood in modern criminal investigations which can often be seen in detective mystery films, further increasing interest in chemistry.

The diaryl oxalate-hydrogen peroxide system is a chemiluminescence system with simple principles, obvious effects, and great fun. The chemical energy of the reaction is converted into light energy through the dye in the system. It is extensively used in light-emitting toys, emergency lighting, search and rescue, and other fields. Depending on the dyes used, chemiluminescence can emit colorful visible light and invisible infrared light. The scientific experiment discussed in this paper used several chemiluminescence dyes to introduce the principle of chemiluminescence, the range of red, green, blue, and infrared emission wavelengths, and the principle of using red, green, and blue light to achieve multiple colors. In this paper, we designed several scientific chemiluminescence experiments such as the mixed luminescence of different dyes, volcanic eruption simulation, homemade chemiluminescence highlighters, the colorful chemiluminescence of chalk, homemade light sticks, etc. These experiments are entertaining, lively, and interesting.

Electrolytes are critical in electrochemistry. Recently, novel concepts of electrolytes have emerged, which give new insights into traditional electrolytes. To broaden students' knowledge and cultivate innovative and scientific development thinking, it is necessary to introduce these new concepts into physical chemistry teaching. In this experiment, two types of deep eutectic solvents based on choline chloride were prepared as solvent and electrolyte, and then the viscosity and conductivity were measured to improve the understanding of the characteristics of deep eutectic solvents. Lastly, cyclic voltammetric experiments of CuCl₂ with a glassy carbon electrode and Pt electrode in deep eutectic solvents were carried out. Here, we introduce scientific research into physical chemistry teaching, to cultivate students' scientific thinking abilities and improve their interests in chemistry research.

Self-healing ionic gel was prepared and its strain and humidity sensing test were performed. It is designed as a laboratory experiment for general chemistry of first-year undergraduates. After content expanding, the experiment can also be used as a comprehensive experiment for the students majored in applied chemistry, polymer chemistry and materials science and engineering. The ionic gel was prepared by free radical polymerization of vinyl-3-butyl imidazolium tetrafluoroborate ([VBIm][BF₄]) to form cross-linked polymer matrix (PIL). Whereas 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF₄]) (IL) was behaved as solvent and additive to the PIL. Because of the existence of free ionic liquid IL molecules in the gel, the PIL/IL ionic gel had a good electrical conductivity, which caused an excellent response to the strain by force or the humidity in air. The gel was also self-healable due to the strong ionic bonding interaction.

Melamine is a widely used industrial raw material that forms stones after ingestion, causing great damage to the kidneys. Because of its high nitrogen content, melamine is often illegally added to milk powder to improve the nitrogen content. Therefore, the qualitative and quantitative detection of melamine in the food industry is critical. This study was based on the supramolecular self-assembly strategy; cyanuric acid was selected as the detection reagent to form the supramolecular structure with melamine, and methylene blue was used as an indicator through the interaction of melamine and cyanuric acid. The melamine in milk powder was quantitatively detected by an ultraviolet spectrophotometer. The reaction conditions of this experiment were mild, the color change was clear, the detection limit was low, and the sensitivity was high. The experiment can be divided into many experimental units and is a novel experiment, thus making it suitable for the undergraduate teaching.