Free Radical Chain Reaction Research Articles

Green Preparation of Ammonium Polyphosphate With Shell–Core Structure for Enhancing Fire Safety of Thermoplastic Polyurethane

ABSTRACTIn the recent years, the development of high‐performance flame retardants (FRs) for thermoplastic polyurethane (TPU) has become increasingly important due to its wide applications in various industries and the growing demand for fire safety. In this study, ammonium polyphosphate (APP) was used as the core, whereas chitosan (CS) and nano‐silica (SiO2) served as the shell to create a shell–core‐structured FR through a self‐assembly process in an aqueous phase. APP, APP@CS, and APP@CS@SiO2 were incorporated into TPU at a concentration of 20 wt%, and their effects on TPU properties were compared. The findings showed that APP@CS@SiO2 exhibited superior flame retardancy for TPU. Compared to pure TPU, the TPU/APP@CS@SiO2 showed reductions in peak heat release rate, total heat release, peak smoke production rate, total smoke production, peak CO production rate, and peak CO2 production rate by 58%, 80%, 80.5%, 89.1%, 20.4%, and 60.1%, respectively. Additionally, APP@CS@SiO2 effectively inhibited the thermal degradation of TPU and enhanced its thermal stability, resulting in the residual carbon content of the composite rising to 28.5%, which is about 20 times higher than that of pure TPU. In conclusion, APP@CS@SiO2 significantly improved the fire safety of TPU by efficiently catalyzing char formation in the condensed phase, diluting flammable gases, and hindering gas‐phase free radical chain reactions, thereby opening new avenues for the practical application of TPU composites.

Methionine thioether reduces the content of 4-hydroxy-2-nonenal in high-temperature soybean oil by preventing the radical chain reaction.

This study investigated how methionine (Met) reduced 4-hydroxy-2-nonenal (4-HNE) generation during the heating of soybean oil. The results showed that Met at 5mM, 10mM, 15mM, 20mM and 30mM reduced the 4-HNE content by 0.67%, 58.86%, 66.35%, 86.62% and 82.39%, respectively, as detected by liquid chromatography coupled to tandem mass spectrometry. Additionally, a decrease in the content of alkyl radicals, alkyl peroxyl radicals and alkoxyl radicals with increasing Met concentration was detected by electron spin resonance. Combined with the subsequent identification of the adducts of Met with the three radicals, it could be shown that Met reduces the 4-HNE content by preventing the free radical chain reaction. Finally, the kinetics simulations of the reaction between 4-HNE and Met indicated that adducts formed by the two cannot be stabilized in high-temperature systems. This study offers insights into safe oil processing and the antioxidant mechanisms of Met thioether.

Experimental study on controlled oxidation of active sites in closed fire zone thermal decomposition coal

ABSTRACT Reignition often occurs after the fire area is unsealed, many people attribute it to the reoxygenation of smoldering coal. However, there were also case of reignition after the fire area was extinguished. In this study, the optimal gas ratio was obtained and confirmed by controlled oxidation experiments under different ratios of O2-N2 and O2-CO2. The mechanism of controlled oxidation technology was investigated through experiments involving Multi-component Adsorption Breakthrough Curves, FTIR, and ESR. The results show that the thermal decomposition process of coal-generated numerous active sites, which led to the re-ignition of the closed fire zone. However, controlled oxidation technology can slowly consume the active sites without causing a drastic temperature rise. It is found that 5% O2 and 95% CO2 are the best atmospheres for controlled oxidation technology. Forty grams of coal was oxidized at room temperature under air conditions, and the coal core temperature rise rose 1.99°C. However, under controlled oxidizing gas atmosphere, the temperature rise was reduced by 71%. This was due to the controlled oxidized atmosphere impeding the reaction of coal with oxygen. The free radical content of the controlled oxidized coal was 3.01 × 1016 spins/g, which was lower than that of the air-oxidized coals. This difference was attributed to the suppression of free radical chain reactions in the controlled oxidized atmosphere. The research results provide a feasible idea to unseal the extinguished fire area safely.

The Cathode-Electrolyte Interface Constructed with Antioxidant Ascorbic Acid Guides LNMO to Achieve Stable Cycling Under High Voltage Conditions.

LiNi0.5Mn1.5O4 (LNMO) is considered one of the most promising cathode materials for high-energy-density lithium-ion batteries (LIBs). However, free-radical-induced carbonate electrolyte decomposition is a key factor hindering the improvement of battery stability. Inspired by the antioxidative properties of ascorbic acid (AA) in scavenging free radicals, the addition of AA during the electrode fabrication process can effectively terminate free radical chain reactions within the cycling of LNMO. This action prevents severe electrolyte decomposition, thus stabilizing the cathode-electrolyte interface (CEI) and ultimately enhancing battery stability. The results demonstrate that LNMO||Li half-cell with the addition of AA show significantly improved cycling performance after 1000 cycles at 1 C, with a high capacity retention rate of 87.4%, surpassing the 43.6% retention rate achieved by batteries using PVDF alone as a binder. This work introduces an efficient and straightforward strategy for designing functional additives to stabilize phase interfaces, offering an economically efficient choice to enhance the electrochemical performance of the LNMO.

Mechanism of methyl elaidate on the thermal oxidation behavior

The effects of cis–trans isomerization on the oxidation products of oleic acid (composites and structure characterization) were investigated. The reduction of thermal oxidation reaction of methyl elaidate (ME) was 6.72 % lower than that of methyl oleate (MO), and the oxidation products (core aldehydes) first increased and then decreased with the prolongation of thermal oxidation time. ME exhibited better oxidation stability than MO in free radicals, hydroperoxides, double bonds, aldehydes, and glycerides. The oxidation products were mainly 11-oxo-9-undecenoate (initial stage) and methyl 9-oxononanoate (later stage), following the free radical chain reaction mechanism. The H8 in double bond was more easily dehydrogenated in the chain initiation stage than H11, followed by the formation of core aldehyde through three intermediates and two transition states each pathway. ME required a higher energy barrier (1.3–13.6 kJ/mol) than MO reaction, making it more difficult for ME to undergo thermal oxidation reaction. The transition state 4 and 5 were rate determining steps of chain initiation reaction and proliferation reaction, respectively. This study was of great significance to further control the formation of these trans fats and their oxidation products.

Lignin‐based nitrogen and phosphorus‐containing polylactic acid with flame‐retardant performances

AbstractPolylactic acid (PLA) is a new type of biodegradable material that has been applied in many fields such as extrusion, injection molding, film drawing, and spinning. In contrary, it does not have flame retardancy. In this paper, N‐PCDL was synthesized by amidation reaction between COOH of PCDL and NH2 of tetraethylenepentamine (TEPA), followed by an Atherton‐Todd reaction of unreacted NH2 at the other end of TEPA with PH of DOPO to prepare a novel lignin‐based flame retardant containing nitrogen and phosphorus (NP‐PCDL). The Fourier transform infrared spectroscopy (FT‐IR) and nuclear magnetic hydrogen spectroscopy (1H NMR) analysis results showed that proton peaks of CONH, PN, and NH appeared in the NP‐PCDL spectrum, while the characteristic absorption peak of PH bond disappeared in DOPO, the X‐ray photoelectron spectroscopy (XPS) results showed that the degraded lignin consisted of elements C and O, while NP‐PCDL consisted of elements C, O, N and P. The above results indicated that NP‐PCDL was successfully prepared. NP‐PCDL accounted for 3% (mass percentage, the same below), 5% and 10% of PLA, then lignin based flame‐retardant PLA composites were prepared by internal mixing and injection molding. Thermogravimetric analysis (TGA) showed that the residual carbon of PLA/3% NP‐PCDL, PLA/5% NP‐PCDL and PLA/10% NP‐PCDL at 800°C were higher than that of pure PLA, with the increase of 56.56%, 97.54%, and 301.64%, respectively; The analysis of SEM, XPS, and Raman showed that PLA/NP‐PCDL formed dense, regular and highly graphitized residual carbon with phosphorus nitrogen structure during the combustion process. At the same time, NH3, H2O and PO˙ free radicals were released, which could dilute combustible gases, destroy free radical chain reaction, isolate combustible gases and heat, so as to play a flame‐retardant role.

Hydrogen therapy from the initiation to its practical applications

Molecular hydrogen (H2) has emerged as a therapeutic and prophylactic agent devoid of adverse effects. H2 demonstrates multifaceted functionality across diverse cell types and organs, attributable to its interaction with oxidized hemes as a fundamental molecular mechanism. Given the abundance of various heme types both intracellularly and extracellularly, the broad-ranging effects of H2 are comprehensible. Subsequent Pathways are mediated by end-or modified- products of lipid peroxide followed by free radical chain reactions. Notably, H2 confers benefits not only to patients afflicted with diseases but also to individuals seeking to enhance health and wellness. The mission of hydrogen medicine encompasses addressing unresolved medical challenges, including cerebral infarction, post-cardiac arrest syndrome, advanced cancer, metabolic syndrome, and dementia. Transitioning from animal experiments to clinical studies is imperative to confront these formidable diseases effectively.

Revealing the Intrinsic Correlation between Cu Scales and Free Radical Chain Reactions in the Regulation of Catalytic Behaviour.

Defining the copper-based catalysts that are responsible for the catalytic behaviour of oil-paper insulation systems and implementing effective regulation are of great significance. Accelerated ageing experiments were conducted to reveal variations in copper scales and deterioration in insulation properties. As ageing progressed, TEM images demonstrated that copper species were adsorbed and aggregated on the fibre surface in the form of nanoparticles (NPs). The scale of NPs exhibited a continuous increase, from 27.06 nm to 94.19 nm. Cu(I) and Cu(II) species were identified as the active sites for inducing intense free radical reactions, which significantly reduced the activation energy, making the insulating oil more susceptible to oxidation. The role of the antioxidant di-tert-butyl-p-cresol (DBPC) in extending the insulation life was regulated by determining the optimal addition time based on variations in the interfacial tension. After the second addition of DBPC, the ageing rates of the dissipation factor, acidity, micro-water and breakdown voltage in the Cu+DBPC group decreased by 28.8%, 43.2%, 52.9% and 46.7%, respectively, compared to the Cu group. This finding not only demonstrates the crucial role of DBPC in preventing the copper-based catalyst-induced oxidation of insulating oil, but also furnishes a vital foundation for enhancing the long-term stability of transformer insulation systems.

Research Progress on the Intervention of Traditional Chinese Medicine in Signal Pathways Related to Acute Cerebral Infarction

Acute cerebral infarction is a disease with high incidence, mortality, and disability rates. Its etiology is complex, and the exact pathogenesis is not yet fully understood. Current studies often involve inflammatory responses, apoptosis, oxidative stress, atherosclerosis, excitotoxicity, and free radical chain reactions. Signal pathways play a crucial role in the occurrence and development of this condition. Traditional Chinese medicine can improve the condition of patients with acute cerebral infarction by intervening in multiple signal pathways. This paper systematically reviews recent literature, identifying 11 key signal pathways, including NLRP3, TLR4/NF-κB, Nrf2/ARE, CD40/CD40L, JAK/STAT, PI3K/AKT, JNK/p38 MAPK, Wnt, Notch, RhoA/ROCK, and ERK1/2. The aim is to provide some reference for the research on traditional Chinese medicine treatments for acute cerebral infarction.

Research on the Potential of Persistent Free Radicals Triggering Open-Pit Coal Oxidation and Spontaneous Combustion

ABSTRACT This study attempts to reveal the triggering pathways of open-pit coal oxidation and spontaneous combustion from the perspective of persistent free radicals (PFRs). To this end, electron spin resonance technology, spin trap technology, and quantum chemical calculations were combined to study the occurrence characteristics of PFRs in coal and their photoreaction characteristics. Based on typical coal molecular fragments, the mechanism of PFRs triggering open-pit coal oxidation was further revealed. The results indicate that coal contains abundant PFRs, which produce reactive oxygen species (ROS) after exposure to sunlight, mainly including hydroxyl radicals (•OH) and superoxide anion radicals (O2 •−). Among them, the higher the initial content of PFRs or the longer the time of sunlight exposure, the more favorable it is for the production of •OH, the concentration of photoinduced •OH remains at the level of 1011 spin/mm3. Compared to O2 in the air, these photoinduced •OH have stronger oxidizing properties and can trigger free radical chain reactions of coal oxidation at room temperature (activation energies ＜ 40 kJ/mol), releasing reaction heat (average enthalpy change is −65.53 kJ/mol). As a common oxidant in coal spontaneous combustion (CSC) process, O2 does not possess these abilities (activation energies greater than 190 KJ/mol and enthalpy change greater than 160 KJ/mol). From the perspectives of thermodynamics and kinetics, PFRs in coal have the potential to indirectly trigger open-pit coal oxidation and spontaneous combustion. Therefore, the efficient quenching of PFRs or inhibiting the production of •OH will be beneficial for preventing the oxidation and spontaneous combustion of open-pit coal. This study provides a new perspective on revealing the mechanism of CSC and developing new inhibitors.

Polycyclic aromatic compounds surface modulation of TiO2@SiO2 nanoparticles enhances the insulation performance of polypropylene film

Polypropylene (PP) film is an important component of metallized film capacitors. However, the insulation issues of polypropylene film significantly affect the safe and stable operation of capacitors. In this study, polycyclic aromatic compounds (PAC) were introduced to the surface of TiO2@SiO2 nanoparticles via chemical grafting, preparing Ti@Si-PAC nanofillers, to achieve modulation of the nanoparticle/PP interface. The experimental and simulation results indicate that Ti@Si-PAC/PP exhibits excellent insulation performance. The study indicates that the surface modulation of nanoparticles by PAC introduces a ‘soft interface’ between the nanoparticles and the polypropylene matrix. The ‘soft interface’ enhances the interfacial interaction, reduces dielectric loss, and introduces deep traps, exhibiting a significant inhibitory effect on carrier migration. Additionally, the introduction of PAC enhances the electron trapping capability in the interface region, which plays a positive role in quenching free radical chain reactions and reducing the damage of high-energy electrons to polypropylene molecular segments. This study provides an effective method for enhancing the insulation performance of polypropylene.

DFT-based computational analysis of 2,4-dimethyl-6-tert-butylphenol (DTBP) as an antioxidant in aviation fuels

Antioxidants are indispensable additives for ensuring the long-term stability, performance, and reliability of aviation fuels. They prevent the formation of gum and other insoluble deposits in the fuel which clog fuel systems, leading to engine problems. This is achieved by inhibiting free radical chain reactions involved in the oxidation of hydrocarbons in the fuel. The compound 2,4-Dimethyl-6-tert-butyl phenol (DTBP) is one of the widely used antioxidants in aviation fuels. In this report, the radical scavenging done by DTBP is analysed computationally by density functional theory (DFT) with the model chemistry X/6-31+G(d,p), where X represents certain Minnesota functionals such as MN15, M05-2X, M06-2X, M08-HX, and M11. Among the well-known modes of radical scavenging, namely HAT, SETPT, and SPLET, the HAT mode is preferred in the gaseous phase, while SPLET operates in non-polar solvents, as computations indicate. Fukui indices, global reactivity descriptors, electronic spectra, and natural bond orbitals (NBOs) are also generated to explain the results. Understanding the mechanism of radical scavenging is important in designing powerful and efficient antioxidants for aviation fuels such as jet fuel, aviation gasoline, Jet B, and bio-kerosene.

Alwyn George Davies. 13 May 1926—1 September 2023

Alwyn Davies was one of the last surviving members of Christopher Ingold (FRS)'s research group, a set of chemists who together transformed our understanding of mechanistic organic chemistry and laid the foundation for modern teaching of the subject. His early independent research on organic peroxides led into organometallic peroxides and thence into organometallic chemistry. His monographs Organic peroxides (1961, Butterworths) and Organotin chemistry (1997, 2004, Wiley) helped to promote the rapid growth of these topics. One route to organometallic peroxides was the reaction of organometallic compounds with dioxygen, and Alwyn Davies showed that these reactions occurred by a free radical chain reaction. Perhaps his greatest contribution was to establish that radical reactions would often occur at the metal centres in main group organometallic compounds, sometimes a million times faster than at hydrogen. He used electron spin resonance (ESR) spectroscopy to monitor the products and rates of these reactions, and to study the properties of the organic radicals that were produced. The theme of metals behaving as hydrogen surrogates permeated much of the work. In his later career, he developed improved methods for generating organic radical cations, and he recorded and analysed their unusual ESR spectra.

System-wide coordination and communication of lipid metabolism atlas revealed cytotoxicity of epoxy triglyceride in deep-frying oil

The epoxy triglycerides generated by oxidation, cyclization, and free radical chain reaction of unsaturated dietary oils during deep-frying are demonstrated to have cytotoxicity and can induce lipid metabolism related diseases. Metabolic diseases are usually characterized by metabolic abnormalities in different tissues, however, the relationship between changes in intratissue coordination and communication induced by epoxy triglycerides and specific pathogenic mechanisms remains largely unknown. We conducted lipid metabolomics analysis across six different tissues in C57BL/6J mice, including the medial prefrontal cortex, interscapular brown adipose tissue, epididymal white adipose tissue, liver, intestine, and heart. Normal diet intake demonstrated a high degree of association between lipid metabolites, indicative of cross-communication and cooperation among various tissues and organs, while, a global correlation that was disrupted and restructured by epoxy triglycerides intake. Examination of blood samples revealed that epoxy triglycerides enhanced bacterial translocation from the gut to the systemic circulation, consequently stimulating the TLR4/CD36/NF-κB pathway. In summary, this study found that epoxy triglyceride upsets the comprehensive coordination and information exchange of lipid metabolism, providing a fresh perspective for future research on the systemic metabolic network and identifying metabolic disease markers and associated mechanisms induced by deep-frying oil.

A multifunctional tannic acid binder for 5.0 V LiNi0.5Mn1.5O4 electrodes and its interfacial characterization

Due to the higher working voltage of spinel LiNi0.5Mn1.5O4 (LNMO), the electrolyte degrades at high potentials, leading to the generation of numerous alkyl radicals.The transition metals will dissolve under high-voltage reactions, resulting in an unstable LNMO/electrolyte interface, ultimately deteriorating the battery’s cycling performance. In this study, a PAALi-TAc composite binder was obtained through the crosslinking of polyphenolic hydroxides Tannic acid (TAc) with PAALi. The electrode fabricated using this binder achieved a maximum capacity of 132.6 mAh g−1 at a 1 C rate. After 100 cycles, the capacity remained at 130.3 mAh g−1, with a retention rate of 98.2%. Even after 400 cycles, the capacity was maintained at 113.2 mAh g−1, with a retention rate of 85.3%. During the 400 cycles of high-current fast charge and discharge at 5 and 10 C, the capacity retention rates were 89.3% and 88.0%, respectively. The PAALi-TAc binder played a crucial role in establishing a compatible electrolyte interface by terminating the free radical chain reactions and chelating the excess dissolved metals in high-voltage LNMO//Li batteries, and this led to improved cycling and rate performance.

Sustainable cycling and mechanism of Co(II)/Co(IV)/Co(III) with S(IV) highly triggered by Co(IV) in E/Co(II)/S(IV) for enhanced removal of reactive brilliant red X-3B

The massive discharge and inadequate treatment of dye wastewater have led to the extensive accumulation of azo dyes in natural water bodies, which is a severe threat to human health. In this study, a novel homogeneous electrochemical system, denoted E/Co(II)/S(IV), was developed by the incorporation of an electric field and cobalt/sulfite. Notably, the decontamination efficiency of the E/Co(II)/S(IV) system for reactive brilliant red X-3B (X-3B) was 95.14 % within 10 min, which was accomplished by utilizing only a trace amount of Co(II). The entire process exhibited an exceptionally low energy consumption of only 0.331 kWh/m3. Single-factor experiments were conducted to explore the influence of various operational parameters and water matrix components on the system decontamination efficiency. By combining the chelator EDTA and chemical probe PMSO, the presence of Co(III) and Co(IV) was detected. The results showed that Co(IV) mainly triggered the chain reaction. The activation products of S(IV), including SO3•−, SO4•−, SO5•− and HO∙, played a dominant role in the degradation of X-3B, with SO4•− having the most substantial contribution. Under anodic oxidation, Co(II) underwent double-electron transfer, leading to the conversion of Co(II) into Co(IV). Subsequently, Co(IV) activated S(IV) via a single-electron transfer mechanism, initiating a free radical chain reaction. During the reaction, Co(IV) transformed into Co(III) and Co(II), thus achieving the Co(II)/Co(IV)/Co(III) cycle. The generation of oxygen as a result of the electrochemical process offers a viable solution for addressing the issue of hypoxia stemming from the rapid activation of S(IV). The active sites in the X-3B molecule were elucidated through density functional theory predictions, and three degradation pathways for X-3B were identified via mass spectrometry analysis. The toxicological characteristics of both X-3B and its degradation products were comprehensively assessed using toxicity estimation software tool and algal culture experiments. This research offers valuable insights into the refinement of cobalt/sulfite systems and introduces innovative concepts for electrochemical applications, which have broad-reaching implications for dye wastewater purification.

Augmented degradation performance of dielectric barrier discharge plasma via optimized hydroxyl radical generation

Dielectric barrier discharge (DBD) plasma demonstrates significant potential for eliminating chlorinated aromatic compounds (CACs), while its commercial application has been hampered by inadequate generation and diffusion of active species. In response, this work introduced iron-biochar composites (Fe/BC) into DBD system to enhance the generation of highly oxidative hydroxyl radicals (OH) from underutilized O3 and H2O2, thereby reducing the diffusion of OH and accelerating the degradation of CACs. The results indicated that, in just 15 min, the combined system achieved remarkable degradation rates exceeding 95% for six diverse CACs, with the degradation rate constant increasing up to 4.27 times when compared to DBD alone. Moreover, the varied response of pollutants implied that the enhanced degradation efficiency was primarily facilitated by the reduced mass transfer distance between pollutants and formed OH. The activation of O3 on Lewis acidic sites not only directly promoted the generation of OH through free radical chain reactions but also indirectly induced more conversion of H2O2 into OH by facilitating the Fe3+/Fe2+ cycle. The identification of intermediates and toxicity analysis substantiated its environmental sustainability. This study offers a viable technical pathway and theoretical foundation for enhancing the efficiency of plasma-based treatment of organic wastewater.

Photocatalytic fuel cell assisted by Fenton-like reaction for p-Chloronitrobenzen degradation and electricity production through S-scheme heterojunction C3N5 modified TNAs photoanode: Performance, DFT calculation and mechanism

Photocatalytic fuel cell (PFC) is a promising technology to recover usable energy from wastewater through the degradation of pollutants, whereas the complex preparation procedures and high photogenerated carrier recombination efficiency of photoanode remains an urgent challenge to improve the PFC performance. Herein, PFC with S-scheme heterojunction C3N5/TNAs photoanode assisted by Fenton-like reaction (C3N5/TNAs-PFC-Fenton) system was built for p-Chloronitrobenzene degradation and electricity production. The working function confirmed the band bending of C3N5 and TNAs, and density functional theory calculations indicated the formation of internal electric field at heterojunction interface of C3N5 and TNAs, which promoted visible-light absorption capacity and charge transfer property of C3N5/TNAs photoanode. The incorporation of Fenton-like reaction into C3N5/TNAs-PFC-Fenton system could effectively enhance p-Chloronitrobenzene degradation and electricity production by participating in free radical chain reaction and stimulating electron transfer. The radical trapping experiments confirmed that •OH and photogenerated electron were main reactive species, and photogenerated hole, •O2− and 1O2 were also participated in p-Chloronitrobenzene degradation. The p-Chloronitrobenzene degradation pathway was interpreted and the overall toxicity of p-Chloronitrobenzene was relieved after treatment in C3N5/TNAs-PFC-Fenton system. The C3N5/TNAs-PFC-Fenton system exhibited fine universality for degradation of organic pollutants and electricity production.

Explosion suppression characteristics of modified ABC powder driven by argon/CO2

This paper changed ABC powder and performed a comparison on the suppression of methane explosions between pure modified powder under various operating circumstances and cold aerosols induced by various inert gases (argon, CO2). The results show that the maximum explosion pressure and flame velocity greatly decrease when inert gases act as catalytic gases. Different inert catalytic gases have various inhibitory effects on cold aerosols. Argon can delay the arrival of explosion overpressure. CO2 gas can produce bidirectional inhibitory effects from inerting and free radical chain reactions. It not only delays the occurrence of explosion overpressure, but also enhances explosion suppression ability. The most effective inhibitor is the cold aerosol, which contains 0.06 g/L of modified powder and 24% CO2 gas. Finally, under the influence of inert gases (argon, CO2), the modified ABC powder creates a cold aerosol that can more effectively suppress methane explosions.

Study on the catalysis of copper-based compounds on coal spontaneous combustion and its mechanism

ABSTRACTTo study the effect of the copper element in coal on the spontaneous combustion process of coal, corresponding copper-containing compounds were added to the coal-based on their occurrence state, and thermodynamic experiments and in-situ diffuse reflectance infrared spectroscopy experiments were conducted. Thermodynamic oxidation experiments have shown that the catalytic effects of Cu (NO3)2, CuCl2, CuCl, and Cu2O on three types of coal with different degrees of metamorphism are mainly reflected in the accelerated oxidation stage. After adding copper-containing compounds, the ignition temperature of coal decreased by 22.1°C to 134.4°C, the heat release increased by 1.33 to 3.19 times, and the CO emission and oxygen consumption rate also increased. CuCl has the greatest impact on the ignition point temperature of coal and increases the oxygen consumption rates of DNH and TS by 2.32 and 1.51 times that of raw coal. CuCl2 has the strongest catalytic effect on coal oxidation heat release. Through in-situ diffuse reflectance infrared spectroscopy experiments, it was found that the reaction rate of fatty hydrocarbons in the oxidation process of three types of coal with the addition of copper-containing compounds increased to 1.3–3 times that of raw coal, and the oxidation rate of oxygen-containing functional groups also significantly increased, while the cracking temperature of aromatic structures significantly decreased. This is because copper ions, as strong free radicals, induce free radical chain reactions in coal and exhibit a strong promoting effect on the coal oxygen reaction process.