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1. Intramolecular β-Alkenylation of Cyclohexanones via Pd-Catalyzed Desaturation-Mediated C(sp³)–H/Alkyne Coupling

Author:
Wang, Chengpeng; Naren, Nevin A.; Zheng, Pengfei; Dong, Guangbin
Source:
Journal of the American Chemical Society 2020 v.142 no.19 pp. 8962-8971
ISSN:
1520-5126
Subject:
chemical bases,   etc   ; acids; alkynes; catalytic activity; chemical bonding; cyclohexanones; hydrides; moieties; palladium; protonation;     Show all 10 Subjects
Abstract:
... Site-selective C–C bond formation through the direct coupling of C(sp³)–H bonds with unsaturated hydrocarbons represents an atom-economical and redox-neutral way to functionalize chemically inert positions, such as those β to a carbonyl group. While most existing β-functionalization methods utilize a directing group (DG) strategy, here we report a Pd-catalyzed intramolecular β-alkenylation of keto ...
DOI:
10.1021/jacs.0c02654

2. Retention of acidic and basic analytes in reversed phase column using fluorinated and novel eluent additives for liquid chromatography-tandem mass spectrometry

Author:
Veigure, Ruta; Lossmann, Krit; Hecht, Max; Parman, Elisabeth; Born, Rasmus; Leito, Ivo; Herodes, Koit; Kipper, Karin
Source:
Journal of chromatography 2020 v.1613 pp. 460667
ISSN:
0021-9673
Subject:
chemical bases,   etc   ; acids; additives; ammonium acetate; ammonium bicarbonate; chemical species; liquid chromatography; pH; tandem mass spectrometry;     Show all 9 Subjects
Abstract:
... This research focuses on retention mechanisms in a LC column with C18 stationary phase when novel eluent additives (HFIP, HFTB and TFE as well as NFTB and perfluoropinacol) are used. The retention factors between novel eluent additives and conventional ones like ammonium acetate and ammonium bicarbonate at different eluent pH values were compared. A simple set of drug-like molecules, widely spread ...
DOI:
10.1016/j.chroma.2019.460667

3. Adenine-functionalized polypropylene glycol: A novel stationary phase for gas chromatography offering good inertness for acids and bases combined with a unique selectivity

Author:
Xiong, Xue; Qi, Meiling
Source:
Journal of chromatography 2020 v.1612 pp. 460627
ISSN:
0021-9673
Subject:
chemical bases,   etc   ; acids; additives; adsorption; chemical species; gas chromatography; isomers; naphthalene; phenols; polyethylene glycol; polypropylenes;     Show all 11 Subjects
Abstract:
... This work presents the investigation of utilizing adenine-functionalized polypropylene glycol (APPG) for capillary gas chromatographic separations. The statically coated APPG column (0.25 mm i.d.) showed moderate polarity and high column efficiencies of 4660 plates/m and 4376 plates/m determined by n-octanol and naphthalene, respectively. Remarkably, the APPG column baseline resolved all the compo ...
DOI:
10.1016/j.chroma.2019.460627

4. Highly Stable Upconverting Nanocrystal–Polydiacetylenes Nanoplates for Orthogonal Dual Signaling-Based Detection of Cyanide

Author:
Oh, Jongwon; Jeon, Inkyu; Kim, Dowon; You, Younghoon; Baek, Dahye; Kang, Seok Ju; Lee, Jiseok
Source:
ACS applied materials & interfaces 2020 v.12 no.4 pp. 4934-4943
ISSN:
1944-8252
Subject:
chemical bases,   etc   ; acids; anions; chemical interactions; color; cyanides; drinking water; fluorescence; hydrophobicity; mechanical stress; nanocrystals; solvents;     Show all 12 Subjects
Abstract:
... Although the unique optical signaling properties of polydiacetylene (PDA) have been exploited in diverse bio-chemosensors, the practical application of most PDA sensor systems is limited by their instability in harsh environments and fluorescence signal weakness. Herein, a universal design principle for a highly stable PDA sensor system with a practical dual signaling capability is developed to de ...
DOI:
10.1021/acsami.9b20438

5. Radicals derived from Lewis acid/base pairs

Author:
Liu, Liu Leo; Stephan, Douglas W.
Source:
Chemical Society reviews 2019 v.48 no.13 pp. 3454-3463
ISSN:
1460-4744
Subject:
chemical bases,   etc   ; Lewis acids; free radicals;     Show all 3 Subjects
Abstract:
... While conventional approaches to stabilizing main group radicals have involved the use of Lewis acids or bases, this tutorial review focuses on new avenues to main group radicals derived from combinations of donor and acceptor molecules. Reactions involving the use of both classical Lewis acid–base adducts and frustrated Lewis pair systems are discussed and the subsequent reactivity is considered. ...
DOI:
10.1039/c8cs00940f

6. Application of regression-kriging and sequential Gaussian simulation for the delineation of forest areas potentially suitable for liming in the Jizera Mountains region, Czech Republic

Author:
Borůvka, Luboš; Vašát, Radim; Němeček, Karel; Novotný, Radek; Šrámek, Vít; Vacek, Oldřich; Pavlů, Lenka; Fadrhonsová, Věra; Drábek, Ondřej
Source:
Geoderma regional 2020 v.21 pp. e00286
ISSN:
2352-0094
Subject:
chemical bases,   etc   ; acidification; atmospheric deposition; base saturation; cations; conservation areas; decision making; forests; liming; models; mountains; organic horizons; peat; probability; Czech Republic;     Show all 15 Subjects
Abstract:
... Acidification due to acid atmospheric deposition affected strongly soils of many forested areas with long-term consequences. Liming is often used for amelioration, however, detailed assessment of soil and stand conditions is necessary to avoid possible undesirable effects. The aim of this paper is to apply and compare two spatial modelling methods to delineate probability that the criteria for pot ...
DOI:
10.1016/j.geodrs.2020.e00286

7. Modelling long-term impacts of fertilization and liming on soil acidification at Rothamsted experimental station

Author:
Xu, Donghao; Carswell, Alison; Zhu, Qichao; Zhang, Fusuo; de Vries, Wim
Source:
The Science of the total environment 2020 v.713 pp. 136249
ISSN:
0048-9697
Subject:
chemical bases,   etc   ; acidity; aluminum; arable soils; base saturation; cations; fertilizers; grasses; grasslands; liming; neutralization; nitrogen; simulation models; soil acidification; soil pH; sulfur; topsoil; United Kingdom;     Show all 18 Subjects
Abstract:
... Liming is widely used to reduce the impacts of soil acidification and optimize soil pH for agricultural production. Whether models can simulate the effect of liming on soil pH, and base saturation (BS), and thereby guide lime application, is still largely unknown. Long-term experimental data from a grassland (Park Grass, 1965–2012) and arable land (Sawyers Field, 1962–1972) at Rothamsted Research, ...
DOI:
10.1016/j.scitotenv.2019.136249

8. Synergistic Effects of Inexpensive Mixed Metal Oxides for Catalytic Hydrothermal Liquefaction of Food Wastes

Author:
Cheng, Feng; Tompsett, Geoffrey A.; Murphy, Caroline M.; Maag, Alex R.; Carabillo, Nicholas; Bailey, Marianna; Hemingway, Jeremy J.; Romo, Carla I.; Paulsen, Alex D.; Yelvington, Paul E.; Timko, Michael T.
Source:
ACS sustainable chemistry & engineering 2020 v.8 no.17 pp. 6877-6886
ISSN:
2168-0485
Subject:
chemical bases,   etc   ; acids; biofuels; calcium; carbon; catalysts; catalytic activity; clay; crystal structure; energy; food waste; heat; hydrothermal liquefaction; industrial wastes; leaching; oxides; synergism;     Show all 17 Subjects
Abstract:
... Industrial wastes and natural mixed oxide materials were evaluated as inexpensive heterogeneous catalysts for catalytic hydrothermal liquefaction (CHTL) of food wastes. Red mud and red clay achieved biocrude carbon yields of 47.0 and 39.5% with higher heating values (HHVs) of 40.2 and 37.7 MJ kg–¹, respectively, which were much greater than those without the catalyst (biocrude carbon yield of 19.7 ...
DOI:
10.1021/acssuschemeng.0c02059

9. Enabling an atom-economic production of chiral amino alcohols by electrodialysis with bipolar membranes

Author:
Gao, Wei-Ting; Chen, Qing; Du, Ming-Gu; Zhang, Wei-Ming; Cao, Chang-Yan; Song, Wei-Guo
Source:
Green chemistry 2020 v.22 no.7 pp. 2213-2224
ISSN:
1463-9270
Subject:
chemical bases,   etc   ; alanine; amino alcohols; byproducts; catalysts; catalytic activity; cost analysis; drugs; electrodialysis; feedstocks; green chemistry; hydrochloric acid; hydrogen; hydrogenation; phosphoric acid; stereoselective synthesis; sulfuric acid;     Show all 17 Subjects
Abstract:
... Optically pure amino alcohols are widely used as essential building blocks of catalysts and auxiliaries in asymmetric synthesis, especially in pharmaceuticals. Catalytic hydrogenation has been regarded as the most effective route to produce chiral amino alcohols, but it is still unsatisfactory, which mainly manifests in the involvement of extra acids and bases, thus generating a large amount of in ...
DOI:
10.1039/c9gc02460c

10. Effect of gap size and forest type on mineral nitrogen forms under different soil properties

Author:
Kučera, Aleš; Holik, Ladislav; Cerro, Elena Muñoz; Petříček, Jan
Source:
Journal of forestry research 2020 v.31 no.2 pp. 375-386
ISSN:
1007-662X
Subject:
chemical bases,   etc   ; Fagus sylvatica subsp. sylvatica; Picea abies; ammonium; ammonium nitrogen; cation exchange capacity; forest ecosystems; forest management; forest types; mixed forests; nitrate nitrogen; nitrates; nitrogen; soil minerals;     Show all 14 Subjects
Abstract:
... Gaps play a key role in forest ecosystem development and result from either natural processes or targeted forest management activities. The aim of this study was to investigate the interrelationships of soil properties in each of three forest types and two treatments, and to identify factors that influence levels of soil mineral nitrogen forms. The relation between mineral nitrogen and factors of ...
DOI:
10.1007/s11676-018-0822-3

11. New insights into the chemical bases of wine color evolution and stability: the key role of acetaldehyde

Author:
Forino, Martino; Picariello, Luigi; Lopatriello, Annalisa; Moio, Luigi; Gambuti, Angelita
Source:
European food research & technology 2020 v.246 no.4 pp. 733-743
ISSN:
1438-2377
Subject:
chemical bases,   etc   ; acetaldehyde; catechin; color; mass spectrometry; metabolites; model food systems; nuclear magnetic resonance spectroscopy; p-coumaric acid; polymers; pyruvic acid; red wines; ultraviolet-visible spectroscopy;     Show all 13 Subjects
Abstract:
... The reactivity of malvidin-3-O-glucoside with acetaldehyde, pyruvic and p-coumaric acids, was separately studied in wine model solution in the presence and absence of catechin, by UV–Visible spectrophotometry, NMR and Mass spectrometry. These naturally occurring metabolites were selected on account of their role in determining the red wine color. The scientific bases underlying the wine color are ...
DOI:
10.1007/s00217-020-03442-x

12. Chronic and episodic acidification of streams along the Appalachian Trail corridor, eastern United States

Author:
Burns, Douglas A.; McDonnell, Todd C.; Rice, Karen C.; Lawrence, Gregory B.; Sullivan, Timothy J.
Source:
Hydrological processes 2020 v.34 no.7 pp. 1498-1513
ISSN:
0885-6087
Subject:
chemical bases,   etc   ; acidification; aquatic ecosystems; atmospheric deposition; cations; ecoregions; emissions; nitrogen; sediments; soil; streams; sulfates; sulfur; surface water; Eastern United States; Europe;     Show all 16 Subjects
Abstract:
... Acidic atmospheric deposition has adversely affected aquatic ecosystems globally. As emissions and deposition of sulfur (S) and nitrogen (N) have declined in recent decades across North America and Europe, ecosystem recovery is evident in many surface waters. However, persistent chronic and episodic acidification remain important concerns in vulnerable regions. We evaluated acidification in 269 he ...
DOI:
10.1002/hyp.13668

13. The amelioration effects of canola straw biochar on Ultisol acidity varied with the soil in which the feedstock crop was cultivated

Author:
Wang, Hui; Dong, Ying; Tong, Xuejiao; Liu, Xinghai; Shao, Jie; Shi, Renyong; Hong, Zhineng; Xu, Renkou; Jiang, Jun
Source:
Journal of soils and sediments 2020 v.20 no.3 pp. 1424-1434
ISSN:
1439-0108
Subject:
chemical bases,   etc   ; Ultisols; acid soils; acidity; alkalinity; application rate; biochar; canola; carbonates; cations; crops; feedstocks; pyrolysis; soil pH; straw; temperature; China;     Show all 17 Subjects
Abstract:
... PURPOSE: Regional differences in the alkaline properties and base cation richness of canola straw biochars, and their amelioration effects on an acidic Ultisol, were studied in the present investigation. MATERIALS AND METHODS: The biochars were produced using straw from canola crops grown in four different regions and soils from south to north of China as feedstock, namely Yingtan biochar (YTBC), ...
DOI:
10.1007/s11368-019-02504-2

14. Recommendations for Improving Methods and Models for Aquatic Hazard Assessment of Ionizable Organic Chemicals

Author:
Escher, Beate I.; Abagyan, Ruben; Embry, Michelle; Klüver, Nils; Redman, Aaron D.; Zarfl, Christiane; Parkerton, Thomas F.
Source:
Environmental toxicology and chemistry 2020 v.39 no.2 pp. 269-286
ISSN:
0730-7268
Subject:
chemical bases,   etc   ; bioaccumulation; ecotoxicology; guidelines; hazard characterization; hydrophobicity; lipids; mitochondria; models; organic acids and salts; pH; quantitative structure-activity relationships; screening; toxicity; toxicity testing; zwitterions;     Show all 16 Subjects
Abstract:
... Ionizable organic chemicals (IOCs) such as organic acids and bases are an important substance class requiring aquatic hazard evaluation. Although the aquatic toxicity of IOCs is highly dependent on the water pH, many toxicity studies in the literature cannot be interpreted because pH was not reported or not kept constant during the experiment, calling for an adaptation and improvement of testing g ...
DOI:
10.1002/etc.4602

15. Calibration of Mehlich-3 with Bray P1 and Ammonium Acetate in the Tri-State Region of Ohio, Indiana and Michigan

Author:
Culman, Steve W.; Mann, Meredith; Sharma, Stuti; Saeed, Muhammad Tariq; Fulford, Anthony M.; Lindsey, Laura E.; Brooker, Aaron; Dayton, Elizabeth; Warden, Randall; Joern, Brad
Source:
Communications in soil science and plant analysis 2020 v.51 no.1 pp. 86-97
ISSN:
1532-2416
Subject:
chemical bases,   etc   ; Mehlich-3 phosphorus; ammonium acetate; calcium; cations; field crops; magnesium; nutrient content; nutrients; phosphorus; potassium; potassium fertilizers; soil; Indiana; Michigan; Ohio;     Show all 16 Subjects
Abstract:
... Field crop fertilizer recommendations for Ohio, Indiana and Michigan are currently based on the Bray P1 extractant for phosphorus (P) and the ammonium acetate extractant (AA) for base cations. The fertilizer recommendations in this Tri-State region are currently being revised and will use the Mehlich-3 soil test extractant as the new basis for P and potassium (K) fertilizer recommendations. The go ...
DOI:
10.1080/00103624.2019.1695825

16. Methoxy-Substituted Nitrodibenzofuran-Based Protecting Group with an Improved Two-Photon Action Cross-Section for Thiol Protection in Solid Phase Peptide Synthesis

Author:
Bader, Taysir K.; Xu, Feng; Hodny, Michael H.; Blank, David A.; Distefano, Mark D.
Source:
Journal of organic chemistry 2019 v.85 no.3 pp. 1614-1625
ISSN:
1520-6904
Subject:
chemical bases,   etc   ; acids; bioactive properties; cysteine; geranylgeranyl diphosphate synthase; lighting; moieties; organic chemistry; peptides; photolysis; thiols;     Show all 11 Subjects
Abstract:
... Photoremovable caging groups are useful for biological applications because the deprotection process can be initiated by illumination with light without the necessity of adding additional reagents such as acids or bases that can perturb biological activity. In solid phase peptide synthesis (SPPS), the most common photoremovable group used for thiol protection is the o-nitrobenzyl group and related ...
DOI:
10.1021/acs.joc.9b02751

17. Rational Design of Multi-Stimuli-Responsive Scaffolds: Synthesis of Luminescent Oligo(ethynylpyridine)-Containing Alkynylplatinum(II) Polypyridine Foldamers Stabilized by Pt···Pt Interactions

Author:
Chan, Michael Ho-Yeung; Leung, Sammual Yu-Lut; Yam, Vivian Wing-Wah
Source:
Journal of the American Chemical Society 2019 v.141 no.31 pp. 12312-12321
ISSN:
1520-5126
Subject:
chemical bases,   etc   ; acids; luminescence; nuclear magnetic resonance spectroscopy; pyridines; solvents; temperature;     Show all 7 Subjects
Abstract:
... A series of oligo(ethynylpyridine)-containing alkynylplatinum(II) terpyridine/bzimpy (bzimpy = 2,6-bis(N-alkylbenzimidazol-2′-yl)pyridine) metallofoldamers has been designed and synthesized to investigate the potential applications of metallofoldamers imparted by the rich spectroscopic responses of Pt···Pt interactions. Apart from the control of the folding/unfolding processes by solvent compositi ...
DOI:
10.1021/jacs.9b04447

18. Capillary electrophoretic apparatus for the endpoint detection in microtitration methods

Author:
Oukacine, Farid; Choisnard, Luc; Gèze, Annabelle; Peyrin, Eric
Source:
Journal of chromatography 2019 v.1597 pp. 220-224
ISSN:
0021-9673
Subject:
chemical bases,   etc   ; acids; capillary electrophoresis; chromatography; drugs; electric current; metal ions; titration;     Show all 8 Subjects
Abstract:
... Titration methods are routinely used in the laboratories for the quantification of acids and bases, for the complexometric determination of metal ions and for the ion-pair titrations of drugs in pharmaceutical control. They also find application in a wide variety of chemical and biochemical studies. However, conventional titration methods (CTM) require large amounts of samples that are not always ...
DOI:
10.1016/j.chroma.2019.03.014

19. Efficient and one-pot synthesis of novel sulfamates from carboxylic acids

Author:
Atmaca, Ufuk
Source:
Tetrahedron 2019 pp. 130467
ISSN:
0040-4020
Subject:
chemical bases,   etc   ; acetonitrile; carboxylic acids; catalysts; chemical reactions; chemical structure; prices; solvents; sulfamates; synthesis;     Show all 10 Subjects
Abstract:
... Effective synthesis of novel sulfamates from various carboxylic acids has been developed in the presence of chlorosulfonyl isocyanate (CSI) in mild conditions. Several acids, bases and solvents effects were investigated for one-pot synthesis sulfamates as a catalyst. Finally, triflic acid was found to possess efficiently under optimized conditions in acetonitrile. This method is easy, fair price a ...
DOI:
10.1016/j.tet.2019.130467

20. R2R Fabrication of Pore-Filling Cation-Exchange Membranes via One-Time Impregnation and Their Application in Reverse Electrodialysis

Author:
Yang, SeungCheol; Choi, Young-Woo; Choi, Jiyeon; Jeong, Namjo; Kim, Hanki; Nam, Joo-Youn; Jeong, Haejun
Source:
ACS sustainable chemistry & engineering 2019 v.7 no.14 pp. 12200-12213
ISSN:
2168-0485
Subject:
chemical bases,   etc   ; acids; cation-exchange membranes; electrodialysis; electrolytes; energy efficiency; polymers; solvents; toxicity;     Show all 9 Subjects
Abstract:
... Pore-filling ion-exchange membranes have been produced via complex, low energy efficient, and toxic processes, including repetitive impregnation to fully fill the porous substrates with polymer electrolytes, and using polar organic solvents and acids/bases for optional postmodifications. In the present work, we analyzed the characteristics of a pore-filling cation-exchange membrane (PCEM) fully fi ...
DOI:
10.1021/acssuschemeng.9b01450