Case Studies in Thermal Engineering
·
2025
·
IF 6.4
Juan Cheng,Chengyang Cao,Chong Xia,Guangyao Zheng,Chuan Zhang,Hongyun Hu
Nitrobenzene (NB), as a critical chemical intermediate with annual consumption exceeding one million tons, is widely used in the chemical manufacturing industry. However, its poor thermal stability when contaminated with impurities has caused multiple fire and explosion incidents. This study aims to investigate the effects of two typical phenols, p-nitrophenol (PNP) and o-nitrophenol (ONP), on the thermal behaviors of NB, and elucidate the impact mechanism. Experimental results indicate that the addition of 10% wt. PNP or ONP significantly reduces the main decomposition peak temperature of NB, initiating low-temperature exothermic reactions. Kinetic analysis reveals that while these additives increase the activation energy, the dramatic rise in pre-exponential factor indicates fundamental changes in the decomposition pathway. Specifically, NB-ONP exhibits the highest apparent activation energy due to intramolecular hydrogen bonding. Cleavage of these hydrogen bonds generates highly reactive phenoxy radicals that drive an efficient nitro-reduction pathway, leading to the most pronounced thermal hazard. Pure NB decomposition follows a second-order reaction model (F2), while mixtures with PNP or ONP conform to nucleation-growth (A3) and first-order (F1) models, respectively. Product analysis confirms that phenolic impurities reconstruct the reaction network through more complex pathways. Consequently, the thermal hazard risk follows NB-ONP>NB-PNP>NB. These findings provide crucial guidance for NB production: priority should be given to controlling high-risk ONP impurity generation by optimizing nitration process conditions to suppress relevant side reactions. The study clarifies the microscopic mechanism and provides important theoretical basis for targeted impurity management and safe NB production.
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PROPELLANTS EXPLOSIVES PYROTECHNICS
·
2023
·Vol. 48
·期 5
·e202200253
·
IF 1.8
Ting You,An Chen,Yimei Liao,Qiang Tian,Xiaohui Duan
To shed light on the structure-property relationship of a methylnitroguanidine (MeNQ)-nitroguanidine (NQ) eutectic, its thermal behavior and microstructure were studied by various techniques. The eutectic composition of MeNQ-NQ with the lowest melting temperature ( T m ) of 149.9 °C was at the mole ratio of 7 : 3, as determined by temperature-composition ( T-X ) and melting enthalpy-composition ( H-X ) diagrams. The MeNQ-NQ eutectic exhibited a homogeneous network structure composed of the plate-shaped MeNQ and acicular NQ enriched phases that resulted in a uniform melting around the T m observed by in situ variable temperature optical microscopy. The X-ray diffraction from MeNQ-NQ eutectic showed peaks that were shifted to low scattering angle, an indication of the expansion of its crystal lattice and the formation of solid solutions. Small-angle X-ray scattering from the sample showed a rough interface between the MeNQ- and NQ-enriched phases. Infrared spectral data showed absorption peaks due to −NH 2 and −CH 3 groups that were red shifted relative to the raw materials, an indication of hydrogen bond interactions between MeNQ and NQ molecules.
研究领域:
材料科学
·
化学
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Environmental Science & Technology Letters
·
2021
·
IF 7.653
Wangjin Yang,Di You,Chunhui Li,Chong Han,Ning Tang,He Yang,Xiangxin Xue
Nitrous acid (HONO) significantly contributes to OH radicals in the atmosphere, whereas the HONO sources need to be urgently further explored. The photolysis of solid nitroaromatic compounds (Ar-NO2), including nitrophenols (NPs) and nitro-polycyclic aromatic hydrocarbons (NPAHs), was investigated in a cylindrical reactor coupled to a NOx analyzer at the ambient pressure. The formation of HONO and NOx (NOx = NO2 + NO) by the photolysis of five NPs and four NPAHs was quantified. HONO and NO formations from Ar-NO2 were obviously enhanced under irradiation. For NPs, the Ar-NO2 photolysis frequency for HONO (JAr-NO2→HONO) and NO (JAr-NO2→NO) formations varied in the range of (0.34–4.16) × 10–7 and (0.38–3.21) × 10–7 s–1, respectively. For NPAHs, JAr-NO2→HONO and JAr-NO2→NO were measured to be (0.02–2.01) × 10–5 and (0.001–1.59) × 10–4 s–1, respectively. The photolysis of Ar-NO2 in aerosols was estimated to establish a HONO source strength lower than 17 ppt·h–1, suggesting that the photolysis of Ar-NO2 may not well explain daytime HONO source strength in the atmosphere.
研究领域:
环境科学
·
大气化学
·
光化学
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CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2017
·
IF 1.174
Jianhua Chen,Xue Sun,Lijing Lin,Xinfei Dong,Yasan He
In the present paper, a metal–organic framework Cr-BDC was prepared and used as adsorbent for adsorption of o -nitrophenol (ONP) and p -nitrophenol (PNP) from aqueous solutions. Cr-BDC was characterized by scanning electron microscopy, transmission electron microscope, X-ray diffraction and BET methods. The results indicate that Cr-BDC gets a very large specific surface area of 4128 m 2 ·g − 1 and pore sizes are concentrated in 1 nm, which is a benefit for using for wastewater treatment . The influences of the adsorption conditions, such as temperature, solution concentration, adsorption time and reusability on adsorption performance were investigated. Cr-BDC exhibited an encouraging uptake capacity of 310.0 mg·g − 1 for ONP, and adsorption capacity of Cr-BDC for ONP is significantly higher than that for PNP under suitable adsorption conditions. The characterizations of adsorption process were examined with the Lagergren pseudo-first-order, the pseudo-second-order kinetic model, and the intra-particular diffusion model. Kinetics experiments indicated that the pseudo-second-order model displayed the best correlation with adsorption kinetics data. Furthermore, our adsorption equilibrium data could be better described by the Freundlich equation. The results indicate that the as-prepared Cr-BDC is promising for use as an effective and economical adsorbent for ONP removal.
研究领域:
环境科学
·
材料科学
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ORGANIC PROCESS RESEARCH & DEVELOPMENT
·
2023
·
IF 3.4
Shichun Weng,Wei Feng,Wenqian Wu,Zichao Guo,Liping Chen,Wanghua Chen
Nitrophenols and corresponding sodium nitrophenolates are the main side products in the production of mononitrobenzene (MNB). These side products are hazardous due to their thermal instability nature. In this article, the thermal decomposition behaviors of nitrophenols and sodium nitrophenolates were first characterized by differential scanning calorimeter and accelerating rate calorimetry techniques. Then, the influence of phenol and sodium phenolate on the thermal decomposition of MNB was studied to clarify the effect of phenolic hydroxyl groups on the thermal stability of nitrophenols. It was found that compared to nitrophenols, the exothermic peaks of sodium nitrophenolates were more intense and presented strongly autocatalytic features. Sodium phenolate could significantly decrease the decomposition temperature of MNB. Aniline was detected as the unique product in the decomposition processes of pure MNB and MNB/sodium phenolate mixtures, and the nitrosobenzene was verified as the intermediate product. It was experimentally proven that sodium phenolate could catalyze the decomposition of nitrosobenzene (the decomposition intermediate of MNB). The violent decomposition of sodium nitrophenols was caused by the intermolecular catalysis effect of phenoxy groups.
研究领域:
化学工程
·
安全科学
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高影响因子
Analytical Methods
·
2025
·
IF 2.6
Zuhang Ding,Jianzheng Wang,Jing Jin,Min-jie Guo,Qinran Li,Zhi Fan,Jin Zhao
This research describes a novel electrochemical sensor based on a polyimide-silver nanowire (PI-AgNWs) composite that is used to modify a glassy carbon electrode (GCE) for the simultaneous detection of multiple nitrophenol isomers (NPs) with high performance. The synergistic effect from polyimide (PI) doped silver nanowires (AgNWs) improved the selectivity and sensitivity of the fabricated sensor. First, the AgNWs was prepared by polyol process, and then composited with PI to obtain the target composite. Subsequently, the composite was characterized in detail and was used to modify GCE for the NPs detection. Afterwards, electrochemical measurements were performed to simultaneous detection for three NPs. Under the optimal condition, the results exhibited that the linear detection range of 1-400 μM for 4-nitrophenol (4-NP), 1-350 μM for both 2-nitrophenol (2-NP) and 3-nitrophenol (3-NP) and the limit of detection (LOD) were 0.081 μM for 2-NP, 0.107 μM for 3-NP, and 0.063 μM for 4-NP, respectively. In addition, the fabricated electrode exhibited excellent reproducibility (RSDs of 2.85% for 2-NP, 2.71% for 3-NP, and 1.80% for 4-NP, respectively) and stability (RSDs of 6.17% for 2-NP, 2.36% for 3-NP, and 3.89% for 4-NP, respectively) over multiple measurements. Moreover, the sensor showed excellent anti-interference capability and was successfully applied to detect NPs analytes in real water samples with recoveries ranging from 91.1% to 109.0%. This study emphasizes the potential application of PI-AgNWs composites for the rapid detection of NPs in the environment.
研究领域:
分析化学
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环境监测
·
纳米材料
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电化学传感
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污染物检测
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PubMed
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AUSTRALIAN JOURNAL OF CHEMISTRY
·
2014
·Vol. 68
·期 6
·919-925
·
IF 1.644
Jianping Wei,Fangmei Li,Junhui Xu,Xinhua Peng
New polynitrostilbenes were directly synthesised by the Knoevenagel condensation of aromatic aldehydes with nitrotoluenes. The differential scanning calorimetry results demonstrated that the introduction of an amino group and C=C double bonds could improve the thermal stability.
研究领域:
有机化学
·
材料科学
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CARBOHYDRATE POLYMERS
·
2019
·
IF 6.044
Shuangyu Xiong,Luminita Marin,Lian Duan,Xinjian Cheng
Nitroaromatic compounds, especially 2, 4, 6-trinitrophenol, have strong biological toxicity and explosive risks, so the detection of 2, 4, 6-trinitrophenol exhibit importantly practical and scientific significance. In this work, three fluorescence functionalized chitosan CNS 3 , CNS 4 and CNS 5 were prepared using chitosan as matrix. When 2, 4, 6-trinitrophenol (TNP) and/or p-nitrophenol (4-NP) was present in spot, these fluorescent chitosan sensors produced notable fluorescence quenching. It renders the chitosan sensing ability to detect TNP and 4-NP selectively and sensitively. The sensing mechanism is investigated as well. When introduced electron-rich moieties to the fluorescent chitosan, the sensitive detecting ability could be obtained. Excellent recognition ability could reach as low as 0.28 μM. The fluorescence fictionalization cause slight influence to the gel performance of chitosan.
研究领域:
分析化学
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环境科学
·
材料科学
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DOI
PubMed
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RESEARCH ON CHEMICAL INTERMEDIATES
·
2015
·Vol. 41
·期 11
·8307-8315
·
IF 1.221
You Kuiyi,Zhou Zhongcang,Jian Jian,Deng Renjie,Liu Pingle,Ai Qiuhong,Luo He’an
A simple method for the preparation of dinitronaphthalene from the nitration reaction of 1-nitronaphthalene with NO 2 as nitration reagent under the mild conditions has been successfully developed in this work. The results indicated that Ni(CH 3 COO) 2 ·4H 2 O catalyst shows better catalytic performances, and the conversion of 1-nitronaphthalene is 33.10 % with 34.10, 23.56, 19.30, and 3.56 % of the selectivity to 1,5-DNN, 1,3-DNN, 1,4-DNN, and 1,8-DNN, respectively, under the optimal reaction conditions. This is a mild, environmentally benign, and economical method for the preparation of dinitronaphthalene.
研究领域:
化学
·
环境科学
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JOURNAL OF LUMINESCENCE
·
2018
·
IF 2.732
YaoYao Qu,Guojuan Ren,Liying Yu,Baoya Zhu,Fang Chai,Lihua Chen
Herein, the fluorescent carbon dots (CDs) has been synthesized by hydrothermal method by using ethylene diamine tetraacetic acid (EDTA) as a raw materials. The prepared CDs exhibited bright blue fluorscence excited by 340 nm with the quantum yield as high as 52%. The CDs possess special fluorescence responses to 2-nitrophenol (2-NP) and 4-nitrophenol (4-NP), and the slump of fluorescence was demonstrated by CDs solution in the case of 2-nitrophenol and 4-nitrophenol existence. The detection limit of 2-NP and 4-NP was calculated at 77 nM and 60 nM, respectively. Meanwhile, the color response to 2-NP and 4-NP can be observed from achromatic solution to yellow by naked eye. All in all, the obtained CDs can be applied as fluorescence and colorimetric probe in environmental protection.
研究领域:
环境科学
·
分析化学
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Energetic Materials Frontiers
·
2025
·
IF 3.9
Yang-rui Cui,Jian-shuo Cheng,Yuan-gang Xu,Ming Lu
Pyrazole derivatives with polynitro groups were extensively researched in energetic material field as they show high energy density and excellent detonation properties, but the specific synthesis process still encounters challenges. In this paper, we firstly combined trinitromethyl, dinitroethyl, oxadiazolyl moieties with pyrazole, successfully designed and synthesized three novel poly-nitro pyrazole energetic compounds by nitration. Their structural features were investigated using single-crystal X-ray diffraction, nuclear magnetic resonance, infrared spectroscopy. 3-(3,5-Dinitro-1 H -pyrazol-4-yl)-1,2,4-oxadiazol-5(4 H )-one ( 12 ) possessed a superior thermal stability (235.1 °C) due to the presence of strong conjugated interaction in this structure. Among all, 3-nitro-1-(trinitromethyl)-1 H -pyrazole-5-carboxylic acid ( 8 ) exhibited a good thermal stability (163.7 °C), a high density of 1.829 g cm −3 at 298 K in combination with excellent detonation properties ( D : 8747 m s −1 ; P : 33.613 GPa). The results indicate that three compounds have promise to act as novel energetic materials and the synthesis provides a direction for polynitro compounds and oxadiazol based energetic compounds.
研究领域:
有机化学
·
含能材料化学
·
物理化学
·
结构化学
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热力学
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爆炸力学
·
分子设计
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NANOTECHNOLOGY
·
2021
·Vol. 32
·期 19
·195705
·
IF 3.874
Zhirun Ji,Yuan Ji,Rui Ding,Lei Lin,Bingzhi Li,Xing Zhang
Nitrobenzene compounds are highly toxic pollutants with good stability, and they have a major negative impact on both human health and the ecological environment. Herein, it was found for the first time that fluorescent DNA-silver nanoclusters (DNA-AgNCs) can catalyze the reduction of toxic and harmful nitro compounds into less toxic amino compounds with excellent tolerance to high temperature and organic solvents. In this study, the reduction of p-nitrophenol (4-NP) as a model was systematically investigated, followed by expending the substrate to disclose the versatility of this reaction. This report not only expanded the conditions for utilizing catalytic reduction conditions of DNA-AgNCs as an efficient catalyst in the control of hazardous chemicals but also widened the substrate range of DNA-AgNCs reduction, providing a new angle for the application of noble metal nanoclusters.
研究领域:
生物化学
·
环境科学
·
纳米生物学
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