Journal of Analytical and Applied Pyrolysis最新文献

{"title":"Dry distillation of pyrolyzed bio-oils: Exploring the evolution mechanism of heat polymerization in algae-derived bio-oils","authors":"Chuan Yuan ,&nbsp;Jiangshan Zhang ,&nbsp;Mao Chen ,&nbsp;Sivakumar Esakkimuthu ,&nbsp;Bin Cao ,&nbsp;Yamin Hu ,&nbsp;Qi Wang ,&nbsp;Shuang Wang ,&nbsp;Anqing Zheng","doi":"10.1016/j.jaap.2025.107302","DOIUrl":"10.1016/j.jaap.2025.107302","url":null,"abstract":"<div><div>This study systematically elucidates the thermal polymerization mechanism of dry distillation residues from algal bio-oil, with a focus on the transformation pathways of functional groups. The thermal polymerization process involves two main stages. First, low-boiling small molecules undergo crosslinking polycondensation to form polyaromatic frameworks, while non-aromatic moieties undergo cyclic polycondensation to enhance the aromaticity of residues. Subsequently, deoxygenation reactions occur, particularly dehydration/demethoxylation of aromatic structures, and furanyl compounds accelerate polymerization by thermally activated ring-opening to generate carbonyl intermediates. For nitrogen-containing species (pyridine, pyrrole, indole, nitriles), heat treatment promotes chain cleavage of long-chain nitriles into short-chain analogs, accompanied by cyclization-aromatization cascade reactions to form pyridine derivatives and methyl-indoles. Critically, thermal polymerization enables nitrogen heterocycles to graft nitrile/alkyl side chains, forming uniquely structured polymeric frameworks. Multi-scale analysis methods reveal that algal bio-oil coordinates synergistic chemical pathways of aromatic condensation, deoxygenation, and nitrogen reorganization under temperature to form residues. These findings highlight the thermal polymerization characteristics of algal bio-oil, providing a theoretical basis for optimizing dry distillation separation of algal bio-oil and subsequent utilization of residues.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"192 ","pages":"Article 107302"},"PeriodicalIF":5.8,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144704015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Co-pyrolysis of sea rice straw and low-density polypropylene: Implications for advancing sustainable fuel production","authors":"Mengke Liu ,&nbsp;Weijian Dong ,&nbsp;Haihan Ni ,&nbsp;Xin Feng ,&nbsp;Xiaohua Lu ,&nbsp;Aihong Li ,&nbsp;Lilong Zhang ,&nbsp;Jiahua Zhu","doi":"10.1016/j.jaap.2025.107283","DOIUrl":"10.1016/j.jaap.2025.107283","url":null,"abstract":"<div><div>Co-pyrolysis of sea rice straw (SR) and low-density polypropylene (LDPP) was systematically investigated to address challenges in valorizing high-ash, high-silicon agricultural residues and plastic waste. Optimal conditions (500 °C, 80 mL/min N₂, SR:LDPP=1:3) synergistically enhanced oil yield by 257.6 % relative to SR pyrolysis alone while drastically improving fuel quality. Comprehensive characterization revealed a 92.8 % reduction in oxygenated compounds and 93.8 % nitrogen reduction, elevating calorific value by 70.3 % to 42.62 MJ/kg. Thermal and spectroscopic analyses (TG-FTIR/GC-MS) demonstrated hydrogen radical transfer from LDPP decomposition as the core mechanism, facilitating deoxygenation through CO/CO₂ formation and hydrocarbon enrichment. This process effectively mitigated SR's inherent limitations—low oil yield and poor stability—while converting waste plastic into valuable hydrogen donors. The study establishes a synergistic route for transforming challenging coastal biomass and plastic pollution into premium bio-oil, achieving 82.2 % carbon content and near-complete nitrogen removal (0.04 wt%). These findings provide critical insights for sustainable waste management in saline agriculture regions, advancing circular economy strategies for problematic feedstocks.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"192 ","pages":"Article 107283"},"PeriodicalIF":5.8,"publicationDate":"2025-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144695345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Co-treatment of brominated epoxy resin waste, copper-based spent catalysts, and dimethylformamide wastewater: Pollutants degradation and resource recovery","authors":"Fu-Rong Xiu,&nbsp;Yuze Chen,&nbsp;Haipeng Zhou,&nbsp;Yingying Qi","doi":"10.1016/j.jaap.2025.107288","DOIUrl":"10.1016/j.jaap.2025.107288","url":null,"abstract":"<div><div>Brominated epoxy resin (BER) is the main nonmetallic component of E-waste. Copper-based spent catalyst (CBSC) derived from the industrial process is a typical type of hazardous waste. N, N-dimethylformamide (DMF) wastewater is a typical organic wastewater. In this study, the DMF wastewater was used to construct a subcritical DMF wastewater (SDW) system for the synergistic co-treatment of BER and CBSC. The inter-conversion of copper species with different valence released from CBSC could promote the generation of hydroxyl radicals (·OH), which significantly improved the decomposition of DMF and debromination of BER. The decomposition products of DMF (CO₂, NH₄⁺, dimethylamine (DMA), methylamine (MA)) could promote the debromination of BER and the release of copper species from CBSC. The HBr produced by debromination of BER could promote the release of copper species from CBSC and the degradation of DMF wastewater. Under the optimal conditions, 98.79 % of bromine was removed from BER and 99.08 % of DMF was degraded. Simultaneously, high-purity (58.94 %) phenol could be obtained and 62.97 % of copper could be leached/recovered from CBSC. The results of life cycle assessment (LCA) indicated that the SDW process proposed in this study was a green and low-carbon co-treatment strategy for BER, CBSC, and DMF wastewater.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"192 ","pages":"Article 107288"},"PeriodicalIF":5.8,"publicationDate":"2025-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144672535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of the molecular structure of precursor pitch from different sources on the structure and properties of mesophase pitch and its derived carbon fibers","authors":"Guangxue Zhou ,&nbsp;Bin Lou ,&nbsp;Luning Chai ,&nbsp;Ning Xiang ,&nbsp;Ronghuan Gou ,&nbsp;Shifu Cheng ,&nbsp;Hongyan Chang ,&nbsp;Dong Liu","doi":"10.1016/j.jaap.2025.107298","DOIUrl":"10.1016/j.jaap.2025.107298","url":null,"abstract":"<div><div>The structure and properties of mesophase pitch and its derived carbon fibers are closely related to the molecular structure of precursor pitch. Exploring the relationship between mesophase characteristics and precursors at the molecular level is of great significance. In this study, mesophase pitch was prepared from petroleum pitch (PP), coal liquefied pitch (CLP), and coal tar pitch (CTP), and the effects of the molecular structures of PP, CLP, and CTP on the structure and properties of mesophase pitch and its derived carbon fibers were systematically investigated. The results showed that PP has the highest H/C atomic ratio of 0.88 and lower aromaticity (<em>f</em>_a = 0.64) due to its rich aliphatic structure (H_α = 30.79 wt%) with a long alkyl side chain. The semi-rigid molecular structure endows MP-PP with a low softening point (292 ℃), wide-domain optical texture, and excellent spinnability. The relatively poor planar structure, smaller microcrystalline structure size, and the low order degree of MP-PP result in a lower tensile strength and Young's modulus of MPCF-PP, which were 1258 MPa and 146 GPa, respectively. CLP exhibits higher aromaticity (<em>f</em>_a=0.70) and a large number of naphthenic structures (H_N = 11.02 wt%), along with a moderate amount of alkyl side chains. The ordered arrangement of aromatic molecules and the formation of large-size microcrystalline structures (<em>d</em>₀₀₂ = 0.3423 nm, <em>L</em>_c =4.36 nm) give MP-CLP flow-domain optical texture and good thermal stability. MPCF-CLP has the highest tensile strength and Young's modulus among the three types, reaching 1364 MPa and 165 GPa, respectively. CTP had the highest aromaticity, the least amount of alkyl side chain, and the highest PI component content of 20.7 wt%, leading to the excessive condensation of MP-CTP, which has a high softening point (312 ℃), the obvious mosaic structure, the poorly ordered microcrystalline structure, and the worst spinnability, resulting in a splitting morphology of MPCF-CTP and the worst mechanical properties. This study provides theoretical support for the refinement of precursor pitch and the preparation of mesophase pitch and its derived carbon fibers.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"192 ","pages":"Article 107298"},"PeriodicalIF":5.8,"publicationDate":"2025-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144695347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Polycyclic aromatic hydrocarbons in biochar: Influence of thermochemical parameters and analytical considerations","authors":"Cai Jen Sia ,&nbsp;Muhammad Raziq Rahimi Kooh ,&nbsp;Lee Hoon Lim","doi":"10.1016/j.jaap.2025.107296","DOIUrl":"10.1016/j.jaap.2025.107296","url":null,"abstract":"<div><div>Biochar is increasingly recognised for its positive impact on agricultural and environmental sustainability. However, a group of organic compounds, polycyclic aromatic hydrocarbons (PAHs), can form during biochar production. The PAH levels in biochar are determined by factors like feedstock type, charring temperature, residence time, and heating rate during the thermochemical process. Generally, higher PAH content results from more intense thermal conditions. Light PAHs mainly form at temperatures below 500°C, while heavy PAHs tend to form at higher temperatures over 500°C. Generally, PAHs can pose health and environmental risks due to their toxicity. Therefore, understanding the risks associated with biochar is essential to ensure its safe application. This literature review will discuss the background of PAHs and biochar, including their occurrence, formation mechanisms, and associated health effects. It will also cover different thermochemical conversion techniques for biochar production, along with common extraction, cleanup and analytical techniques used to analyse PAHs.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"192 ","pages":"Article 107296"},"PeriodicalIF":5.8,"publicationDate":"2025-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144685433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Explicit microrelief-controlled decoupling of initial aerobic decay and leaching (in hummocks) and anaerobic decay (in hollows) in surface layers of a Sphagnum-dominated peatland","authors":"M. Pérez-Rodríguez ,&nbsp;A. Alten ,&nbsp;M. Miler ,&nbsp;J. Kaal","doi":"10.1016/j.jaap.2025.107295","DOIUrl":"10.1016/j.jaap.2025.107295","url":null,"abstract":"<div><div>Understanding decay processes in peat deposits is fundamental for predicting their role as sources or sinks of atmospheric carbon in a changing environment. It is known that the distribution of microhabitats –hummock, lawn and hollow– within peatlands affects organic matter quality and degradation, but microtopography-dependent carbon dynamics are poorly understood on the molecular level. We studied early decomposition across microtopography levels through analyses of superficial moss cores from a <em>Sphagnum</em>-dominated ombrotrophic peatland in Central Germany, and a 400-day incubation experiment, using analytical pyrolysis. Interpretations were aided by analysis of living vegetation and a deep peat core as reference. Stable and labile pools of polysaccharides dominated the pyrolyzates and played a crucial role in decay dynamics. Two distinct degradation processes emerged: 1) anaerobic decay, characterized by loss of polysaccharides and selective preservation of lignin and aliphatic OM; and 2) leaching of labile phenolic compounds (including sphagnum acid) and free carbohydrates with concomitant initial aerobic degradation and selective preservation of structural polysaccharides. The relative importance of these initial decay processes is spatially dependent; anaerobic decay was detectable in only some of the more evolved hollow layers, while aerobic degradation and leaching dominated in hummocks. Sphagnum acid’s molecular markers appeared useful tracers of early decay as it probably has a leaching-sensitive component in hyaline cells (corroborated by SEM micrographs) that is lost rapidly from hummocks, but not from hollows. Hence, the occurrence of sphagnum acid in peat cores is influenced by microrelief position during peat accretion. This study highlights how microhabitat variations within peatlands influence decay mechanisms on the molecular level.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"192 ","pages":"Article 107295"},"PeriodicalIF":5.8,"publicationDate":"2025-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144695343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pyrolysis behavior of multi-component photovoltaic modules waste: A coupled STA-FTIR-MCC and modeling approach","authors":"Yan Ding ,&nbsp;Mengxin Zhang ,&nbsp;Zhiyu Zhou ,&nbsp;Jing Jiao ,&nbsp;Wei Huang ,&nbsp;Hongyun Hu","doi":"10.1016/j.jaap.2025.107292","DOIUrl":"10.1016/j.jaap.2025.107292","url":null,"abstract":"<div><div>With the first million tons of photovoltaics (PV) modules approaching decommissioning, efficient recycling is crucial. Pyrolysis has proven to be an effective method for PV modules recycling. This work details a methodology to characterize the pyrolysis behavior of multi-component PV modules. The mass loss, heat flow, and gaseous products evolution of pyrolyzing PV modules were systematically investigated through simultaneous thermal analysis (STA) and Fourier transform infrared spectroscopy. It was found that the pyrolysis process of PV modules proceeded through four stages, including the melting of polyethylene terephthalate (PET) component, initial thermal decomposition of ethylene-vinyl acetate (EVA) component, progressive pyrolysis of EVA coupled with PET chain scission, and pyrolysis of residual organic matter. The gaseous products were primarily composed of CO₂, H₂O, and carboxylic acids along with their derivatives. The heat released from the combustion of volatile products was measured using microscale combustion calorimetry (MCC). Through the inverse modeling of STA-MCC results using coupled ThermaKin2Ds modeling framework and Hill-climbing optimization method, the pyrolysis reaction kinetics, heat of reactions, heat capacities of condensed-phase components, and heat of combustion of gaseous products were determined. Subsequently, the pyrolysis model of PV modules was developed, accurately reproducing the experimental pyrolysis reaction rate, heat flow, and heat release rate, with total mass loss deviations &lt; 3 %, total integral heat flow deviations &lt; 10 %, and total heat released deviations &lt; 10 %. This model was further testified against experimental data acquired under varied heating conditions. This work can provide guidance for optimizing pyrolysis recycling of PV modules waste.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"192 ","pages":"Article 107292"},"PeriodicalIF":5.8,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144678856","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of different olefinic active species on molecular growth of heavy aromatic fraction in deep processing of thermally cracked oil","authors":"Feng Wang ,&nbsp;Shouhui Jiao ,&nbsp;Xiaoqi Zhang ,&nbsp;Ying Yang ,&nbsp;Xiaohan Jin ,&nbsp;He Liu ,&nbsp;Zongxian Wang ,&nbsp;Aijun Guo","doi":"10.1016/j.jaap.2025.107294","DOIUrl":"10.1016/j.jaap.2025.107294","url":null,"abstract":"<div><div>Although highly reactive olefinic species are abundant in thermally cracked oil, previous studies have predominantly focused on the macroscopic fouling effects of aliphatic olefins during transportation/storage. In contrast, the molecular-level mechanisms by which aromatic olefins promote coking during thermal conversion remained unclear. This work systematically investigated how aromatic olefins drive molecular growth and coke formation of heavy aromatic fractions. Thermal conversion experiments with vacuum residue (VR), resins (Re), and asphaltenes (Asp) mixed with olefin model compounds revealed that aromatic olefins accelerated coking compared to aliphatic olefins, with the coking-promoting effect intensifying as the number of aromatic rings in the molecule increased. At 410°C for 60 min, the addition of 5 wt% 9-vinylanthracene to VR increased the coke yield from 1.35 wt% to 5.72 wt%, versus 1.68 wt% with the addition of 5 wt% 1-octene. Similarly, the addition of 5 wt% 9-vinylanthracene elevated the coke yields for Re and Asp systems from 0.66 wt% and 41.28 wt% to 5.13 wt% and 50.84 wt%, respectively, compared to 1.08 wt% (Re) and 43.36 wt% (Asp) observed with the addition of 1-octene. Model compound system studies demonstrated that, aromatic olefins, unlike 1-octene, could further react with primary addition products formed by their initial co-addition with conventional aromatics, leading to the formation of secondary and high-order addition products. Notably, aromatic olefins exhibited increasing reactivity in continuous co-addition reactions as the number of aromatic rings increased. This was supported by 42.2 % high-order addition products detected in the toluene/9-vinylanthracene system versus 30.1 % in the toluene/styrene system. This study elucidated that aromatic olefin promoted molecular growth through continuous co-addition reactions, ultimately triggering phase separation and coke formation. The findings provided molecular-level insights into the adverse impacts of aromatic olefins on industrial processing of thermally cracked oil.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"192 ","pages":"Article 107294"},"PeriodicalIF":5.8,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144679120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pyrolysis oil upgrading via hydrotreatment to produce alternative fuel using ZrO2-supported catalysts and isopropanol as a solvent","authors":"Nitchakul Hongloi ,&nbsp;Hossein Jahromi ,&nbsp;Tawsif Rahman ,&nbsp;Sushil Adhikari","doi":"10.1016/j.jaap.2025.107293","DOIUrl":"10.1016/j.jaap.2025.107293","url":null,"abstract":"<div><div>Biomass pyrolysis is a promising approach for sustainable bioenergy production, primarily due to its ability to produce a high amount of liquid. However, the high oxygen content in pyrolysis oil limits its applicability in transportation fuels, necessitating deoxygenation for upgrading. Conventional two-step upgrading processes, involving stabilization and hydrotreatment, can be complex and costly. This study investigates a one-step hydrotreatment of fast pyrolysis bio-oil from pine wood using isopropanol (IPA) as a hydrogen-donating solvent to upgrade pyrolysis oil properties. A comprehensive evaluation was conducted to assess the influence of solvent type (IPA vs. glycerol), hydrogen pressure (500 vs. 1000 psi), and catalyst types (NiMo/ZrO₂, CoMo/ZrO₂, NiMo/Al₂O₃, CoMo/Al₂O₃, Ni/SiO₂-Al₂O₃) on the physicochemical characteristics of the upgraded oil. IPA demonstrated superior performance in increasing carbon content of upgraded oil (from 43.9 % to 68.5 %) and higher heating value (from 17.4 to 31.2 MJ/kg), whereas glycerol promoted greater oxygen removal (up to 89.6 %) under moderate pressure (500 psi) with NiMo/ZrO₂. The effect of hydrogen pressure depends on the catalyst type. Among the evaluated catalysts, NiMo/ZrO₂ demonstrated superior performance for pyrolysis oil upgrading. Thermogravimetric analysis indicated minimal coke formation on NiMo-based catalysts, particularly with ZrO₂ support. Simulated distillation results further emphasized the role of reaction time in maximizing jet fuel-range product yields. Catalyst regeneration experiments confirmed that NiMo/ZrO₂ maintains robust deoxygenation activity over three cycles, with only slight deactivation attributed to coke accumulation. This study offers a practical route for efficient one-step pyrolysis oil upgrading using a non-noble catalyst and IPA.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"192 ","pages":"Article 107293"},"PeriodicalIF":5.8,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144695344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Probing into the factors influencing the catalytic performance of ZnO and its catalytic mechanism in dimethyl methylcyclohexyl-2,4-dicarbamate pyrolysis","authors":"Shutong Pang ,&nbsp;Hualiang An ,&nbsp;Guirong Wang ,&nbsp;Xinqiang Zhao ,&nbsp;Yanji Wang","doi":"10.1016/j.jaap.2025.107290","DOIUrl":"10.1016/j.jaap.2025.107290","url":null,"abstract":"<div><div>The pyrolysis of dimethyl methylcyclohexyl-2,4-dicarbamate (HTDC) is one of the most important steps in the highly selective synthesis of methylcyclohexyl-2,4-diisocyanate (HTDI) through the non-phosgene route. In this work, we found that two commercial ZnO samples showed a distinct catalytic performance in HTDC pyrolysis reaction. With the aid of catalyst characterizations of XRD, SEM, TEM, N₂ adsorption-desorption, XPS, TG/DSC, etc, we are convinced that particle size, specific surface area, crystal plane exposed, and oxygen vacancy concentration are responsible for the catalytic performance of ZnO sample. On this basis, ZnO-catalyzed HTDC pyrolysis reaction process was elucidated by the analyses from both in-situ FTIR and the first-principles calculations. The above investigations demonstrated that employing the ZnO catalyst with suitable oxygen vacancy concentration and achieving a rapid separation of HTDI from the reaction system in the reaction process are the keys to attaining highly selective synthesis of HTDI. The pyrolysis of HTDC proceeds by a predominant adsorption on the ZnO surface through the hydrogen atom of the amino group and the oxygen atom of the methoxy group rather than the carbonyl oxygen. And what’s more, the methyl carbamate group in the para-position is pyrolyzed prefercially compared with that in the ortho-position due to the effect of the steric hindrance of methy group. This work paved a new way to highly selective pyrolysis of HTDC to HTDI.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"192 ","pages":"Article 107290"},"PeriodicalIF":5.8,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144656954","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}