当前位置：
X-MOL 学术
›
Environ. Sci. Technol.
›
论文详情
Our official English website, www.x-mol.net, welcomes your
feedback! (Note: you will need to create a separate account there.)
Reaction of Substituted Phenols with Lignin Char: Dual Oxidative and Reductive Pathways Depending on Substituents and Conditions
Environmental Science & Technology ( IF 10.8 ) Pub Date : 2020-11-26 , DOI: 10.1021/acs.est.0c04991 Jing Li 1, 2 , Qingqing Li 2 , Christian E. W. Steinberg 1, 3 , Qing Zhao 4 , Bo Pan 1 , Joseph J. Pignatello 5 , Baoshan Xing 2
Environmental Science & Technology ( IF 10.8 ) Pub Date : 2020-11-26 , DOI: 10.1021/acs.est.0c04991 Jing Li 1, 2 , Qingqing Li 2 , Christian E. W. Steinberg 1, 3 , Qing Zhao 4 , Bo Pan 1 , Joseph J. Pignatello 5 , Baoshan Xing 2
Affiliation
|
Biomass chars are known to be intrinsically redox-reactive toward some organic compounds, but the mechanisms are still unclear. To address this, a char made anoxically at 500 °C from dealkaline lignin was reacted either in the fresh state or after 180-day aging in air with p-nitrophenol (NO2-P), p-hydroxybenzaldehyde (CHO-P), phenol (H-P), or p-methoxyphenol (MeO-P). The reactions were carried out under oxic or anoxic conditions. Degradation occurred in all cases. Both oxidation and reduction products were identified, with yields dependent on the presence or absence of air during reaction or storage. They included oligomers, amines, and ring-hydroxylated compounds, among others. Exposure to air suppressed sorption, annihilated reducing sites, and provided a source of reactive oxygen species that assisted degradation. Sorption suppression was due to the incorporation of hydrophilic groups by chemisorption of oxygen, and possibly blockage of sites by products. Fresh char has comparable electron-donating and accepting capacity, whereas there is a preponderance of electron-accepting over donating capacity in aged char. Under anoxic conditions, both oxidation and reduction occurred. Under oxic conditions or after aging in air, oxidation predominated, and linear free energy relationships were found between the rate constant and the Hammett or Brown substituent electronic parameter or the standard electrode potential of the phenol. The results demonstrate that chars possess heterogeneous redox activities depending on reaction pairs, reaction conditions, and aging.
中文翻译：
取代酚与木质素碳的反应：取决于取代基和条件的双重氧化和还原途径
已知生物质炭对某些有机化合物具有内在的氧化还原反应性，但机理尚不清楚。为了解决这个问题，将脱去碱木质素在500°C下缺氧制得的炭以新鲜状态或在空气中老化180天后与对硝基苯酚（NO 2 -P），对羟基苯甲醛（CHO-P）反应，苯酚（HP）或p-甲氧基苯酚（MeO-P）。反应在有氧或无氧条件下进行。在所有情况下都发生降解。确定了氧化产物和还原产物，其产率取决于反应或储存过程中是否存在空气。它们包括低聚物，胺和环羟基化的化合物等。暴露于空气中抑制了吸附，消除了还原位，并提供了有助于降解的活性氧源。吸附抑制是由于通过氧的化学吸附结合了亲水基团，并且可能堵塞了产物的位点。新鲜的焦炭具有可比的给电子和接受能力，而在老化的焦炭中，电子接受能力高于给体能力。在缺氧条件下，发生氧化和还原。在有氧条件下或在空气中老化后，在速率常数与Hammett或Brown取代基电子参数或苯酚的标准电极电势之间发现了占主导地位的氧化和线性自由能关系。结果表明，取决于反应对，反应条件和老化，炭具有异质氧化还原活性。
更新日期：2020-12-15
中文翻译：
取代酚与木质素碳的反应：取决于取代基和条件的双重氧化和还原途径
已知生物质炭对某些有机化合物具有内在的氧化还原反应性，但机理尚不清楚。为了解决这个问题，将脱去碱木质素在500°C下缺氧制得的炭以新鲜状态或在空气中老化180天后与对硝基苯酚（NO 2 -P），对羟基苯甲醛（CHO-P）反应，苯酚（HP）或p-甲氧基苯酚（MeO-P）。反应在有氧或无氧条件下进行。在所有情况下都发生降解。确定了氧化产物和还原产物，其产率取决于反应或储存过程中是否存在空气。它们包括低聚物，胺和环羟基化的化合物等。暴露于空气中抑制了吸附，消除了还原位，并提供了有助于降解的活性氧源。吸附抑制是由于通过氧的化学吸附结合了亲水基团，并且可能堵塞了产物的位点。新鲜的焦炭具有可比的给电子和接受能力，而在老化的焦炭中，电子接受能力高于给体能力。在缺氧条件下，发生氧化和还原。在有氧条件下或在空气中老化后，在速率常数与Hammett或Brown取代基电子参数或苯酚的标准电极电势之间发现了占主导地位的氧化和线性自由能关系。结果表明，取决于反应对，反应条件和老化，炭具有异质氧化还原活性。
京公网安备 11010802027423号