Article
Chemistry, Organic
Chidvilas Kurapati, Om Singh, Rambabu Gundla
Summary: The synthesis of pongarotene, a furano-rotenoid, was described using thallium(III) p-tosylate as a key step for oxidative 1,2-aryl rearrangement of the sprirochromanone. The structure of pongarotene was confirmed through 2D NMR, HRMS, and X-ray crystallography. The synthesis of sprirochromanones involved radical cyclization of chromone derivatives.
SYNTHETIC COMMUNICATIONS
(2022)
Article
Biotechnology & Applied Microbiology
Dong Zhang, Yuqing Lei, Tingting Wang, Wenqian Lin, Xingyi Chen, Minchen Wu
Summary: This study successfully synthesized (R)-pCPED through bi-enzymatic catalysis. Under optimized reaction conditions, high concentration rac-pCSO was completely hydrolyzed within 5 hours, resulting in high yield and high enantiomeric excess of (R)-pCPED.
FRONTIERS IN BIOENGINEERING AND BIOTECHNOLOGY
(2022)
Article
Chemistry, Physical
David Vesseur, Marte S. M. Holmsen, Didier Bourissou
Summary: p-Allyl complexes of transition metals play important roles in organometallic chemistry and homogeneous catalysis. Palladium(II) p-allyl complexes have received much attention, while their isoelectronic gold(III) counterparts were difficult to obtain. However, this has changed in recent years. This concept article discusses the preparation, characterization, structure, and reactivity of these complexes, as well as their catalytic applications. The influence of the ancillary ligand at gold is analyzed in detail, comparing the similarities and differences with the Pd(II) p-allyl complexes.
Article
Engineering, Environmental
Huan Su, Chao Shan, Xiaolin Zhang, Bingcai Pan
Summary: Chemical oxidation is essential in treating P(I)/P(III)-bearing wastewater. A low-cost catalyst, PdNi10, was developed as an alternative to the noble metal Pd for the chemical-free oxidation of P(I)/P(III) into P(V) by ambient O-2. PdNi10 demonstrated superior catalytic activity and wide applicability in the conversion of P(I) into P(V) under various pH conditions. The oxidation reactions were confirmed to be non-radical pathways, and the involvement of Ni components was found to be negligible. The reactive oxidant species for P(I)/P(III) oxidation were identified as interfacial OH groups resulting from H2O dissociation.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Mining & Mineral Processing
Zhitao Yuan, Xuan Zhao, Jiwei Lu, Hong Lv, Lixia Li
Summary: This study proposed the superconducting high-gradient magnetic separation (SMS) technology for the utilization of abandoned ultrafine ilmenite in the titanium magnetite processing plant in Panzhihua. By optimizing the conditions, a high TiO2 grade and recovery rate were achieved, indicating that a combination of high magnetic field and strong pulsating is critical for effective pre-concentration of ultrafine ilmenite in the SMS process. The results also highlighted that high magnetic intensity and gradient are key factors in the success of SMS technology.
INTERNATIONAL JOURNAL OF MINING SCIENCE AND TECHNOLOGY
(2021)
Article
Materials Science, Multidisciplinary
Xi Lan, Jintao Gao, Zushu Li, Xiang Li, Zhancheng Guo
Summary: Bayan Obo ore in Baotou China is the world's second largest niobium deposit. Due to its low niobium content and complex mineral properties, industrial mining of niobium from this ore has not been established. This study proposed an efficient pre-concentration technique of super gravity to increase the grade purity of niobium in the low-grade niobite. The research successfully achieved complete separation of niobium-rich slag and metallic iron through super gravity at low temperature, obtaining niobium slag with a grade four times higher than the initial ore and high recovery ratios of MFe and Nb2O5.
METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE
(2023)
Article
Chemistry, Multidisciplinary
Naoya Morohashi, Mayu Osawa, Vandana Bhalla, Sahoko Sumida, Yutaka Kato, Ryuki Takahashi, Nobuhiko Iki, Tetsutaro Hattori
Summary: Crystals with a hydrophobic host layer sandwiching a hydrophilic guest recognition space were prepared to selectively collect Yb(iii) from a 0.01 M HCl solution under thermodynamic control.
Article
Engineering, Chemical
Yanghe Liu, Quan Li, Shenghuan Wang, Mengzhu Liang, Yanhong Ji, Zhenyu Cui, Mohammad Younas, Jianxin Li, Benqiao He
Summary: In this study, a new high-performance nanofiltration (NF) membrane with positively and negatively charged groups was developed for efficient Li+/Mg2+ separation. The results showed that the membrane had similar surface and section structure, as well as surface pore size, compared to the original polyamide (PA) membrane. However, the addition of Fe3+ ions improved the Zeta potential of the membrane, indicating the presence of both positively and negatively charged groups on the surface. The membrane exhibited high rejection rates for Mg2+ (97.7%) and permeation rates for Li+ (-87.6%), resulting in a high Li+/Mg2+ separation factor. The fluxes of the three membranes were comparable. These findings suggest that the NF membrane with positively and negatively charged groups has great potential for application in the recovery of lithium from brine.
SEPARATION AND PURIFICATION TECHNOLOGY
(2023)
Article
Chemistry, Analytical
Antonio Cobelo-Garcia, Mirsya E. Mulyani, Jorg Schafer
Summary: The determination of palladium in environmental samples by ICP-MS is challenging due to extensive interferences, but an interference-free methodology for the determination of Pd in natural waters has been successfully achieved by online matrix separation and preconcentration. This method allows for the detection of dissolved Pd in natural samples at low, ambient concentrations, providing valuable data for understanding the behavior of Pd in natural waters.
Article
Engineering, Chemical
Thi Yen Chau Nguyen, Lan-Huong Tran, Kristin K. Mueller, Lucie Coudert, Guy Mercier, Jean-Francois Blais
Summary: A process was developed to produce a fluorite concentrate from a rare earth element (REE) bearing carbonatite, involving flotation, magnetic separation, and hydrochloric acid leaching. After magnetic separation and HCl leaching, the fluorite content in the sample significantly increased, with a high recovery rate achieved.
MINERALS ENGINEERING
(2021)
Article
Chemistry, Multidisciplinary
Rodolfo G. Valle-Altamirano, Maria Camilla Baratto, Isidro Badillo-Ramirez, Francisco Gasteazoro, Rebecca Pogni, Jose M. Saniger, Brenda Valderrama
Summary: The structural determinants responsible for the instability of plant peroxidases towards H2O2 are still unknown. In this study, the formation and decay of compound III, which is generated from the reaction of the catalytically productive radical Fe(IV) =O species with excess H2O2, were investigated. The characterization results suggest that the structure of compound III is more similar to the hydroxyl form of other heme proteins rather than the previously suggested peroxyferryl form.
NEW JOURNAL OF CHEMISTRY
(2022)
Article
Chemistry, Analytical
Muhammad Saqaf Jagirani, Z. Pinar Gumus, Mustafa Soylak
Summary: Covalent organic frameworks (COFs) are emerging as a promising class of porous materials with unique characteristics such as organic backbone, large specific surface, high porosity, multiple functionalities, and structural flexibility. However, limited literature and research gaps hinder the improvement and application of COFs in the separation and pre-concentration of targeted species. This review focuses on assessing and developing COFs-based materials for various applications.
MICROCHEMICAL JOURNAL
(2023)
Article
Chemistry, Analytical
Hao Zhang, Dan-Ni Yang, Zhao-Jing Zhu, Feng-Qing Yang
Summary: A green and novel method for in situ synthesis of silver nanocomposites on paper substrate was developed for the pre-concentration and determination of Fe3+. Tannic acid was used as a reducing and capping agent to synthesize silver nanocomposites under mildly alkaline conditions. The detection of Fe3+ was based on its coordination with tannic acid on the surface of silver nanocomposites and the formation of aggregates. The developed smartphone-assisted paper-based chemical sensor showed a good linear relationship with Fe3+ concentration and demonstrated advantages such as simplicity, ease of synthesis, fast response time, and low reagent/analyte volume requirement.
MICROCHEMICAL JOURNAL
(2023)
Article
Agricultural Engineering
Meijiao Peng, Jiatian Zhu, Yadan Luo, Tao Li, Xuelian Xia, Chengrong Qin, Chen Liang, Huiyang Bian, Shuangquan Yao
Summary: This study achieved efficient separation of bamboo hemicellulose through freeze-thaw-assisted p-TsOH treatment. Compared to conventional methods, better separation effect was achieved with significantly reduced yield of lignin. In addition, an increase in fiber crystallinity index and higher separation selectivity were observed.
BIORESOURCE TECHNOLOGY
(2022)
Article
Engineering, Environmental
Ayse Yuksekdag, Borte Kose-Mutlu, Mark R. Wiesner, Ismail Koyuncu
Summary: The pre-concentration and separation processes of Rare Earth Elements (REEs) were investigated in this study. The nitric acid leachate of e-waste was pretreated to improve its quality before concentration. Nanofiltration was used for pre-concentration, resulting in a triplication of REEs concentration under optimum conditions. A flat sheet supported liquid membrane process was successfully utilized to extract REEs from the pre-treated leachate, with bis-2-ethylhexyl phosphoric acid (D2EHPA) showing higher separation efficiency compared to di-2,4,4,-trimethylpentyl phosphinic acid (Cyanex 272). The processes of direct membrane solvent extraction and MSX with pre-concentration were optimized, and the pre-concentration step was found to increase the efficiency of the MSX process and enable acid recovery. A more environmentally friendly and economical process scheme involving acid recovery from both nanofiltration permeate and post-MSX leaching residue was proposed.
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
(2022)
