o-Carboryne can undergo alpha-CH bond insertion with tertiary amines, thus affording alpha-carboranylated amines in very good regioselectivity and isolated yields. In this process, the nucleophilic ...addition of tertiary amines to the multiple bond of o-carboryne generates a zwitterionic intermediate. An intramolecular proton transfer, followed by a nucleophilic attack leads to the formation of the final product. Thus, regioselectivity is highly dependent upon the acidity of alpha-CH proton of tertiary amines. This approach serves as an efficient methodology for the preparation of a series of 1-aminoalkyl-o-carboranes.
Geographical maldistribution of coal and water resource has led to huge water consumption, posing great challenges to the development of coal chemical industries in China. In this study, based on the ...obtained unit product data of water withdrawal, consumption, and wastewater effluent capacity, the wastewater quantitative information about water quality and relevant energy and reagents consumption for several coal chemical industries were analyzed. Then, the life cycle costs of different types of coal chemical wastewater were analyzed when achieving ICIWD (1st category integrated wastewater discharge) and ZLD (zero liquid discharge) standards. According to the results, the life cycle cost of ICIWD was average 0.94 US$/t water less than that of the wastewater meeting ZLD, because the life cycle boundaries focused on coal chemical industries. Given surface water treatment cost and environment damages value, ICIWD's total cost was 1.07 US$/t water higher than ZLD's. Besides, the consumed water of planning advanced coal chemical projects of 2018 took up 2.8% of total industrial water. Such proportion could even reach over 30% in north and northwest regions. It is suggested that ZLD water policies and water resources appraisal should be introduced to improve and strengthen the rational layout of coal chemical projects.
•Full analysis of water utilization and wastewater treatment is accomplished.•The life cycle costs of wastewater treatment systems are analyzed.•ICIWD's cost is average 1.07 US$/t higher than ZLD's given ecological factors.•Coal chemical projects plan 2018 conflicts with ZLD water policies.•Detailed pathways for achieving ZLD are suggested.
Invited for the cover of this issue is the group of Xiao Wang and Xiaobo Wan at the Chinese Academy of Sciences and Jian Pei at the Peking University. The image depicts thiazoloisoindigo as a novel ...building block that possesses the advantages of both thienoisoindigo (red dragon) and diazaisoindigo (blue dragon). Read the full text of the article at 10.1002/chem.201801432.
“This study presents the first example of the successful preparation of polymerizable thiazoloisoindigo.” Read more about the story behind the cover in the Cover Profile and about the research itself on page 9807 ff. (DOI: 10.1002/chem.201801432).
Oxazoline-containing ligands have been widely employed in numerous asymmetric catalytic reactions. Pyridine-oxazoline-type ligands, a class of hybrid ligands, were designed earlier than bisoxazoline ...and phosphine-oxazoline ligands; however, their unique properties have only been discovered recently. Pyridine-oxazoline-type chiral ligands are rapidly becoming popular for use in asymmetric catalysis, especially for several new and efficient asymmetric methodologies. Several types of challenging asymmetric reactions have been discovered recently using pyridine-oxazoline-type ligands showing their special properties and potential for future application in a wide range of new catalytic methodologies. This review provides an overview of this field, with the aim of highlighting both ligand design and synthetic methodology development.
An overview of advances in the field of pyridine-oxazoline-type ligands and their application in asymmetric catalysis has been presented.
Nasub.3ScFsub.6: 20% Ybsup.3+, 2% Ersup.3+ samples were synthesized with different reaction times and reaction temperatures using the solvothermal method. We carried out a series of tests on Na3ScF6 ...crystals. The XRD patterns showed that the monoclinic phases of the Nasub.3ScFsub.6 samples could be synthesized under different reaction conditions, and doping with Ybsup.3+ ions and Ersup.3+ ions did not change the crystal structures. The SEM images showed that the sizes of the samples gradually increased with reaction time and reaction temperature. The fluorescence spectra showed that the emission peaks of the prepared samples under 980 nm near-infrared (NIR) excitation were centered at 520 nm/543 nm and 654 nm, corresponding to the sup.2Hsub.11/2/sup.4Ssub.3/2→sup.4Isub.15/2 and sup.4Fsub.9/2→sup.4Isub.15/2 transitions, respectively. With the increasing size of the samples, the emission intensities at 654 nm increased and the luminescence colors changed from green to red; at the same time, the red-to-green luminescence intensity ratios (IR/IG ratios) increased from 0.435 to 15.106-by as much as ~34.7 times. Therefore, this paper provides a scheme for tuning the IR/IG ratios of Nasub.3ScFsub.6: 20% Ybsup.3+, 2% Ersup.3+ samples by changing their sizes, making it possible to enhance the intensity of red upconversion, which has great potential for the study of color displays and lighting.
By expanding the scope of sustainability to the entire lifecycle of chemical products, the concept of circular chemistry aims to replace today’s linear ‘take–make–dispose’ approach with circular ...processes. This will optimize resource efficiency across chemical value chains and enable a closed-loop, waste-free chemical industry.
Amines are key intermediates in the chemical industry due to their nucleophilic characteristic which confers a high reactivity to them. Thus, they are key monomers for the synthesis of polyamides, ...polyureas, polyepoxydes, which are all of growing interest in automotive, aerospace, building, or health applications. Despite a growing interest for biobased monomers and polymers, and particularly polyamides, it should be noticed that very few natural amines are available. Actually, there is only chitosan and poly(lysine). In this review we present both fundamental and applied research on the synthesis of biobased primary and secondary amines with current available biobased resources. Their use is described as a building block for material chemistry. Hence, we first recall some background on the synthesis of amines, including the reactivity of amines. Second we focus on the synthesis of biobased amines from all sorts of biomass, from carbohydrate, terpenes, or oleochemical sources. Third, because they need optimization and technological developments, we discuss some examples of their use for the creation of biobased polymers. We conclude with the future of the synthesis of biobased amines and their use in different applications.
Polymers with cyclic topology have no terminal structure and, therefore, exhibit various unique physical and functional properties compared to those of linear analogs. In this paper, we report an ...innovative methodology for the synthesis of cyclic polymers via ring-expansion RAFT (RE-RAFT) polymerization of vinyl monomers using a cyclic trithiocarbonate derivative (CTTC) as a RAFT agent. RE-RAFT of tert-butyl acrylate (TBA) was performed to yield a mixture of polymers exhibiting a bimodal size exclusion chromatography (SEC) trace. Both the peak top molecular weights shifted to higher-molecular-weight regions as the monomer conversion increased. The structure of the resulting polymer mixture was examined by sup.1H NMR and MALDI-TOF-MS. Detailed studies indicated that the obtained polymer of higher molecular weight was one of the large-sized cyclic polymers generated by the fusion of smaller-sized cyclic polymers during the RE-RAFT polymerization process. This approach opens the door to the simple synthesis of well-controlled cyclic polymers with complex structures, such as alternating and multi-block repeat unit sequences.
The radical-involved 1,2-difunctionalization of alkenes has developed into a robust tool for preparation of complex organic molecules. Despite significant advances in this area, the catalytic ...asymmetric version still remains a challenging task mainly due to the difficulty in the stereocontrol of the highly reactive radical intermediates. Recently, owing to the good single-electron transfer ability and coordination with chiral ligands of copper catalysts, remarkable achievements in radical-involved asymmetric alkene difunctionalization have been made
via
synergistic combination of copper and chiral ligands. This tutorial review highlights the recent progress in copper-catalysed radical-involved asymmetric 1,2-difunctionalization of alkenes and the mechanistic scenarios governing the stereocontrol, with an emphasis on utilization of chiral ligands.
This tutorial review highlights the recent progress in copper-catalysed radical asymmetric 1,2-difunctionalization of alkenes.
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