{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,13]],"date-time":"2026-08-13T05:01:29Z","timestamp":1786597289233,"version":"build-2736575974"},"reference-count":54,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2024,1,9]],"date-time":"2024-01-09T00:00:00Z","timestamp":1704758400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>The effect of the structure of promising antioxidant agents with prospective medical use, i.e., unsubstituted and para-substituted annelated triazinylacetic acid hydrazides, on their melting points, thermal stabilities, pyrolysis and oxidative decomposition stages and the type of volatiles emitted under heating with the use of DSC and TG\/DTG\/FTIR\/QMS methods was evaluated and discussed. The melting point of the investigated compounds increased with an enhanced number of electrons (directly correlated with their molecular weight). Melting enthalpy values were determined and presented for all the studied compounds. The pyrolysis and oxidative decomposition processes of the analysed molecules consisted of several poorly separated stages, which indicated a multi-step course of the decomposition reactions. It was found that the thermal stability of the tested compounds depended on the type of substituent at the para position of the phenyl moiety or its absence. In both atmospheres used (air and helium), the thermal stability increased in relation to R as follows: -CH3 \u2264 -OCH3 &lt; -H &lt; -OC2H5. In an inert atmosphere, it was higher by approx. 8\u201318 \u00b0C than in an oxidative atmosphere. The pyrolysis was connected with the emission of NH3, HCN, HNCO, HCONH2, HCHO, CO2, CO and H2O in the case of all the tested compounds, regardless of the substituent attached. In the case of the derivative containing the para-CH3 group, para-toluidine was an additional emitted aromatic product. In turn, emissions of aniline and alcohol (methanol or ethanol) for compounds with the para-OCH3 and para-OC2H5 groups, respectively, were confirmed. In oxidative conditions, the release of NH3, NO, HCN, HNCO, HCONH2, CO2, H2O and cyanogen (for all the compounds) and para-toluidine (for the para-CH3 derivative), aniline (for para-OCH3, para-OC2H5 and unsubstituted derivatives) and acetaldehyde (for the para-OC2H5 derivative) were clearly observed. No alcohol emissions were recorded for either compound containing the para-OCH3- or para-OC2H5-substitututed phenyl ring. These results confirmed that the pyrolysis and oxidative decomposition of the investigated annelated triazinylacetohydrazides occurred according to the radical mechanism. Moreover, in the presence of oxygen, the reactions of volatiles and residues with oxygen (oxidation) and the combustion process additionally proceeded.<\/jats:p>","DOI":"10.3390\/ijms25020813","type":"journal-article","created":{"date-parts":[[2024,1,9]],"date-time":"2024-01-09T04:38:51Z","timestamp":1704775131000},"page":"813","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["Application of Simultaneous and Coupled Thermal Analysis Techniques in Studies on the Melting Process, Course of Pyrolysis and Oxidative Decomposition of Fused Triazinylacetohydrazides"],"prefix":"10.3390","volume":"25","author":[{"given":"Marta","family":"Worzakowska","sequence":"first","affiliation":[{"name":"Department of Polymer Chemistry, Institute of Chemical Sciences, Faculty of Chemistry, Maria Curie-Sklodowska University in Lublin, 33 Gliniana Street, 20-614 Lublin, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1898-5245","authenticated-orcid":false,"given":"Krzysztof","family":"Sztanke","sequence":"additional","affiliation":[{"name":"Laboratory of Bioorganic Compounds Synthesis and Analysis, Medical University of Lublin, 4A Chod\u017aki Street, 20-093 Lublin, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1576-097X","authenticated-orcid":false,"given":"Ma\u0142gorzata","family":"Sztanke","sequence":"additional","affiliation":[{"name":"Department of Medical Chemistry, Medical University of Lublin, 4A Chod\u017aki Street, 20-093 Lublin, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2024,1,9]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"572","DOI":"10.1080\/13510002.2017.1364330","article-title":"Biologically important hydrazide-containing fused azaisocytosines as antioxidant agents","volume":"22","author":"Sztanke","year":"2017","journal-title":"Redox Rep."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"168","DOI":"10.2174\/1389557514666140131111837","article-title":"1,2,4-triazine analogs as novel class of therapeutic agents","volume":"14","author":"Kumar","year":"2014","journal-title":"Mini Rev. Med. Chem."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Z\u00e1le\u0161\u00e1k, F., Slouka, J., and St\u00fdskala, J. (2019). General synthesis of 1-aryl-6-azaisocytosines and their utilization for the preparation of related condensed 1,2,4-triazines. Molecules, 24.","DOI":"10.3390\/molecules24193558"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1898","DOI":"10.1021\/jm201376w","article-title":"Discovery of 1,2,4-triazine derivatives as adenosine A2A antagonists using structure based drug design","volume":"55","author":"Congreve","year":"2012","journal-title":"J. Med. Chem."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"11270","DOI":"10.1021\/acs.jmedchem.2c00804","article-title":"Investigating the Structure-Activity Relationship of 1,2,4-Triazine G-Protein-Coupled Receptor 84 (GPR84) Antagonists","volume":"65","author":"Mahindra","year":"2022","journal-title":"J. Med. Chem."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"3077","DOI":"10.1007\/s10973-020-09886-3","article-title":"Calorimetric (DSC) and dielectric (TSDC) investigation on the thermal behavior and molecular mobility in the supercooled liquid and glassy states of bifonazole and lamotrigine","volume":"145","author":"Diogo","year":"2021","journal-title":"J. Therm. Anal. Calorim."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1371","DOI":"10.1007\/s10973-017-6473-3","article-title":"Thermodynamic approaches for the prediction of oral drug absorption","volume":"130","author":"Fasihi","year":"2017","journal-title":"J. Therm. Anal. Calorim."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"523","DOI":"10.15171\/apb.2015.071","article-title":"Thermal analysis investigation of dapoxetine and vardenafil hydrochlorides using molecular orbital calculations","volume":"5","author":"Attia","year":"2015","journal-title":"Adv. Pharm. Bull."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Epishina, M.A., Kulikov, A.S., and Fershtat, L.L. (2022). Revisiting the synthesis of functionally substituted 1,4-dihydrobenzo[e][1,2,4]triazines. Molecules, 27.","DOI":"10.3390\/molecules27082575"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"104856","DOI":"10.1016\/j.jaap.2020.104856","article-title":"Decomposition mechanism of annelated triazinones bearing the para-nitrophenyl group","volume":"149","author":"Worzakowska","year":"2020","journal-title":"J. Anal. Appl. Pyrolysis"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Ostasz, A., \u0141yszczek, R., Sztanke, K., and Sztanke, M. (2023). TG-DSC and TG-FTIR Studies of Annelated Triazinylacetic Acid Ethyl Esters\u2014Potential Anticancer Agents. Molecules, 28.","DOI":"10.3390\/molecules28041735"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"105226","DOI":"10.1016\/j.jaap.2021.105226","article-title":"Pyrolysis and oxidative decomposition mechanism of trifluoromethylated fused triazinones","volume":"157","author":"Worzakowska","year":"2021","journal-title":"J. Anal. Appl. Pyrolysis"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"369","DOI":"10.1007\/s13738-013-0308-3","article-title":"Synthesis, in vitro lipoxygenase inhibition, docking study and thermal stability analyses of novel indole derivatives. Non-isothermal kinetic study of potent LOX inhibitor N\u2019-(diphenylmethylene)-2-(1H-indole-3-yl)acetohydrazide","volume":"11","author":"Yar","year":"2014","journal-title":"J. Iran. Chem. Soc."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"e6657","DOI":"10.1002\/aoc.6657","article-title":"Spectral studies, thermal investigations, and anticancer activity of some divalent metal complexes derived from 2-(4-bromophenylamino)acetohydrazide ligand","volume":"36","author":"Emara","year":"2022","journal-title":"Appl. Organomet. Chem."},{"key":"ref_15","first-page":"673","article-title":"Synthesis, morphology and theoretical calculations of 1H-benzotriazole-acetohydrazide","volume":"6","author":"Cai","year":"2014","journal-title":"J. Chem. Pharm. Res."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"2923","DOI":"10.1007\/s10854-016-5877-3","article-title":"Solid state thermal decomposition synthesis of CuO nanoparticles from coordinated pyrazolopyridine as novel precursors","volume":"28","author":"Emam","year":"2017","journal-title":"J. Mater. Sci. Mater. Electron."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Wesolowski, M., and Leyk, E. (2023). Coupled and Simultaneous Thermal Analysis Techniques in the Study of Pharmaceuticals. Pharmaceutics, 15.","DOI":"10.3390\/pharmaceutics15061596"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"160","DOI":"10.1016\/j.fpc.2021.11.001","article-title":"On prediction of melting points without computer simulation: A focus on energetic molecular crystals","volume":"2","author":"Bondarchuk","year":"2022","journal-title":"FirePhysChem."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"129","DOI":"10.1016\/j.fpc.2021.05.002","article-title":"Review and prospect of thermal analysis technology applied to study thermal properties of energetic materials","volume":"1","author":"Liu","year":"2021","journal-title":"FirePhysChem."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"2500","DOI":"10.1021\/acs.jced.7b01026","article-title":"Melting point, enthalpy of fusion, and heat capacity measurements of several polyfunctional, industrially important compounds by differential scanning calorimetry","volume":"63","author":"Hogge","year":"2018","journal-title":"J. Chem. Eng. Data"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1900796","DOI":"10.1002\/adem.201900796","article-title":"On the Determination of the Enthalpy of Fusion of\u03b1-Crystalline Isotactic Polypropylene Using Differential Scanning Calorimetry, X-Ray Diffraction, and Fourier-Transform Infrared Spectroscopy: An Old Story Revisited","volume":"22","author":"Lanyi","year":"2020","journal-title":"Adv. Eng. Mater."},{"key":"ref_22","unstructured":"(2023, November 02). NIST Chemistry Webbook. NIST Standard Reference Data, Available online: https:\/\/webbook.nist.gov."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"7675","DOI":"10.1007\/s10973-021-11090-w","article-title":"Thermal stability of polymeric carbon nitride (PCN)-Al2O3-ZrO2 nanocomposites used in photocatalysis","volume":"147","author":"Koltsov","year":"2022","journal-title":"J. Therm. Anal. Calorim."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"205","DOI":"10.1016\/j.jhazmat.2009.08.070","article-title":"TG-FTIR study on urea-formaldehyde resin residue during pyrolysis and combustion","volume":"173","author":"Jiang","year":"2010","journal-title":"J. Hazard. Mater."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"110000","DOI":"10.1016\/j.measurement.2021.110000","article-title":"Thermally enhanced FTIR spectroscopy applied to study of explosives stability","volume":"184","author":"Wojtas","year":"2021","journal-title":"Measurement"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1427","DOI":"10.1016\/S1872-5813(16)30001-9","article-title":"TG-FTIR analysis of nitrogen conversion during straw pyrolysis: A model compound study","volume":"43","author":"Zhou","year":"2015","journal-title":"J. Fuel Chem. Technol."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"16388","DOI":"10.1039\/D0RA10559G","article-title":"Thermal decomposition of ammonium perchlorate-based molecular perovskite from TG-DSC-FTIR-MS and ab initio molecular dynamics","volume":"11","author":"Zhai","year":"2021","journal-title":"RSC Adv."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"33269","DOI":"10.1039\/C4RA05720A","article-title":"Synthesis and thermal degradation property study of N-vinylpyrrolidone and acrylamide copolymer","volume":"4","author":"Xu","year":"2014","journal-title":"RSC Adv."},{"key":"ref_29","first-page":"781","article-title":"Studies on azotetrazolate based high nitrogen content high energy materials potential additives for rocket propellants","volume":"78","author":"Sivabalan","year":"2004","journal-title":"J. Therm. Anal. Calorim."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"74","DOI":"10.1016\/j.tca.2015.09.006","article-title":"Studies on structurally different benzoxazines based on diphenols and diamines: Kinetics of thermal degradation and TG-FTIR studies","volume":"618","author":"Rishwana","year":"2015","journal-title":"Thermochim. Acta"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"106","DOI":"10.1016\/j.jaap.2012.07.013","article-title":"Thermal decomposition of some Diels-Alder adducts of resin acids. Study of kinetics process","volume":"98","author":"Tudorachi","year":"2012","journal-title":"J. Anal. Appl. Pyrolysis"},{"key":"ref_32","unstructured":"(2023, November 03). Available online: https:\/\/webbook.nist.gov\/cgi\/cbook.cgi?ID=C62533&Mask=200#Mass-Spec."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"219","DOI":"10.1016\/S0924-2031(97)00038-6","article-title":"Direct determination of ethanol and methanol in liquid samples by means of vapor phase-Fourier transform infrared spectroscopy","volume":"15","author":"Garrigues","year":"1997","journal-title":"Vib. Spectrosc."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"303212","DOI":"10.1155\/2015\/303212","article-title":"Thermogravimetry-Infrared spectroscopy analysis of the pyrolysis of willow leaves, stems and branchers","volume":"2015","author":"Liu","year":"2015","journal-title":"Adv. Mater. Sci. Eng."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"61","DOI":"10.1016\/j.fuproc.2012.04.015","article-title":"TG-FTIR of pecan shells thermal decomposition","volume":"102","author":"Fasina","year":"2012","journal-title":"Fuel Proc. Tech."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"287","DOI":"10.1208\/s12249-012-9916-y","article-title":"Thermal stability and decomposition kinetic studies of acyclovir and zidovudine drug compounds","volume":"14","author":"Shamsipur","year":"2013","journal-title":"AAPS PharmSciTech"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"638","DOI":"10.3109\/03639045.2010.534099","article-title":"Thermal behavior study and decomposition kinetics of amiodarone hydrochloride under isothermal conditions","volume":"37","author":"Yoshida","year":"2011","journal-title":"Drug Dev. Ind. Pharm."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"175","DOI":"10.1080\/00102207208952518","article-title":"High temperature oxidation of ammonia","volume":"5","author":"Drummond","year":"1972","journal-title":"Combust. Sci. Technol."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"554","DOI":"10.1016\/j.combustflame.2014.08.022","article-title":"Experimental and modelling study on the high-temperature oxidation of ammonia and related NOx chemistry","volume":"162","author":"Mathieu","year":"2015","journal-title":"Combust. Flame"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"250","DOI":"10.4236\/aces.2023.133018","article-title":"An experimental observation of the thermal effects and NO emissions during dissociation and oxidation of ammonia in the presence of a bundle of thermocouples in a vertical flow reactor","volume":"13","author":"Holden","year":"2023","journal-title":"Adv. Chem. Eng. Sci."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"530","DOI":"10.1098\/rspa.1956.0195","article-title":"The gaseous oxidation of aliphatic alcohols. I. Ethyl alcohol: The products formed in the early stages","volume":"237","author":"Cullis","year":"1956","journal-title":"Proc. R. Soc. Lond. A"},{"key":"ref_42","first-page":"982","article-title":"The high-temperature pyrolysis and oxidation of methanol and ethanol: Experimental results and comparison with vehicle emission tests","volume":"103","author":"Taylor","year":"1994","journal-title":"J. Fuels Lubr."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"1691","DOI":"10.1039\/FT9918701691","article-title":"High-temperature oxidation of ethanol. Part 1.\u2014Ignition delays in shock waves","volume":"87","author":"Dunphy","year":"1991","journal-title":"J. Chem. Soc. Faraday Trans."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"251","DOI":"10.1016\/S0082-0784(71)80028-0","article-title":"The high-temperature oxidation of aldehydes","volume":"13","author":"Baldwin","year":"1971","journal-title":"Symp. (Int.) Combust."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"5708","DOI":"10.1039\/C7GC02983G","article-title":"Catalyst-free aerobic oxidation of aldehydes into acids in water under mild conditions","volume":"19","author":"Zhang","year":"2017","journal-title":"Green Chem."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"389","DOI":"10.1016\/j.proci.2018.07.087","article-title":"An experimental and kinetic modelling study of n-C4-C6 aldehydes oxidation in a jet-stirred reactor","volume":"37","author":"Pelucchi","year":"2019","journal-title":"Proc. Combust. Inst."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"101076","DOI":"10.1016\/j.pecs.2023.101076","article-title":"Combustion chemistry of aromatic hydrocarbons","volume":"96","author":"Jin","year":"2023","journal-title":"Prog. Energy Combust. Sci."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"539","DOI":"10.1098\/rspa.1940.0073","article-title":"The combustion of aromatic and alicyclic hydrocarbons. V. The products of combustion of benzene and its monoalkyl derivatives","volume":"175","author":"Burgoyne","year":"1940","journal-title":"Proc. R. Soc. Lond. A"},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"475","DOI":"10.1016\/j.jaap.2006.12.024","article-title":"Evolved gas analyses (TG\/DTA-MS and TG-FTIR) on dehydration and pyrolysis of magnesium nitrate hexahydrate in air and nitrogen","volume":"79","author":"Madarasz","year":"2007","journal-title":"J. Anal. Appl. Pyrolysis"},{"key":"ref_50","doi-asserted-by":"crossref","unstructured":"Schuster, J., Zmrhalova, Z., Pelikan, V., and Matyas, R. (2022). Thermal decomposition mechanism of cuprous thiocyanate in the presence of synthetic air and nitrogen gas. SSRN Electron. J.","DOI":"10.2139\/ssrn.4300067"},{"key":"ref_51","unstructured":"(2023, November 03). Available online: https:\/\/webbook.nist.gov\/cgi\/cbook.cgi?ID=C460195&Mask=200#Mass-Spec."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.pecs.2007.02.004","article-title":"The oxidation of hydrogen cyanide and related chemistry","volume":"34","author":"Dagaut","year":"2008","journal-title":"Prog. Energy Combust. Sci."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"475","DOI":"10.1016\/0010-2180(94)90039-6","article-title":"Mechanism and modeling of hydrogen cyanide oxidation in a flow reactor","volume":"99","author":"Glarborg","year":"1994","journal-title":"Combust. Flame"},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"3707","DOI":"10.1021\/j100242a026","article-title":"Oxidation of hydrogen cyanide in shock waves. Formation of nitrogen monoxide","volume":"87","author":"Higashihara","year":"1983","journal-title":"J. Phys. Chem."}],"container-title":["International Journal of Molecular Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1422-0067\/25\/2\/813\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T13:42:44Z","timestamp":1760103764000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1422-0067\/25\/2\/813"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,1,9]]},"references-count":54,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2024,1]]}},"alternative-id":["ijms25020813"],"URL":"https:\/\/doi.org\/10.3390\/ijms25020813","relation":{},"ISSN":["1422-0067"],"issn-type":[{"value":"1422-0067","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,1,9]]}}}