scholarly journals Unravelling Factors Affecting Directed Lithiation of Acylamino­aromatics

Synthesis ◽  
2018 ◽  
Vol 50 (18) ◽  
pp. 3634-3652 ◽  
Author(s):  
Keith Smith ◽  
Gamal El-Hiti ◽  
Mohammed Alshammari
Keyword(s):  
Aromatic Compounds ◽  
Phenyl Ring ◽  
Low Cost ◽  
Phenyl Group ◽  
Substituted Benzenes ◽  
Factors Affecting ◽  
Ease Of Access ◽  
High Yields ◽  
Anhydrous Solvent

Ureas, pivalamides, and carbamates are widely used as directing metalation groups (DMGs) due to their good directing ability, low cost, ease of access, and ease of removal. Lithiation of substituted benzenes having such directing metalation groups using various alkyllithiums in anhydrous solvent at low temperature provides the corresponding lithium intermediates, but lithiation may take place at various sites. Reactions of the lithium reagents obtained in situ with various electrophiles give the corresponding derivatives, typically substituted at the site(s) where initial lithiation occurred, often in high yields. However, it is often difficult to predict what reagents and/or conditions might be needed to give specific products or to draw general conclusions about the factors that influence the reactions, especially when the reagents, temperature, and solvents used in reported reactions are not directly comparable. In this review, therefore, we attempt to unravel the various factors that influence the lithiation of various simple aromatic compounds containing urea, pivalamide, and carbamate groups.1 Introduction2 Lithiation with DMG Attached Directly to the Phenyl Ring2.1 Influence of the DMG2.2 Influence of Substitution on the Phenyl Ring3 Lithiation with the DMG Separated by a CH2 Group from the Phenyl­ Ring3.1 Effect of the DMG3.2 Influence of Substitution on the Phenyl Ring4 Lithiation with the Phenyl Ring and DMG Separated by Two or More CH2 Groups4.1 Effect of the DMG and Its Distance from the Phenyl Group4.2 Effect of Substituents on the Phenyl Ring5 Conclusions

scholarly journals Two Novel Approaches Used to Produce Biodiesel from Low-Cost Feedstocks

2010 ◽  
Vol 3 (1) ◽  
pp. 23-27 ◽  
Author(s):  
Xiaohu Fan ◽  
Xi Wang ◽  
Feng Chen
Keyword(s):  
High Performance ◽  
Low Cost ◽  
Waste Cooking Oil ◽  
Biodiesel Production ◽  
Economic Viability ◽  
Factors Affecting ◽  
Cooking Oil ◽  
Preliminary Study ◽  
Significant Factors

The price of feedstock is one of the most significant factors affecting the economic viability of biodiesel manufacturer. Many approaches were investigated to reduce the biodiesel production cost. The present work gave a preliminary study of two approaches to economically produce biodiesel from waste cooking oil (WCO) and flaked cottonseed. One was the use of ultrasound-assisted synthesis of biodiesel from WCO. The other was the application of in situ transesterification from flaked cottonseed. Gas chromatography (GC) and High performance liquid chromatography (HPLC) results demonstrated the feasibility of using both approaches to produce biodiesel from low-cost feedstock.

To Eliminate Curtain Effect of FIB TEM Samples by a Combination of Sample Dicing and Backside Milling

2014 ◽  
Author(s):  
Jian-Shing Luo ◽  
Hsiu Ting Lee
Keyword(s):  
Sample Preparation ◽  
Focused Ion Beam ◽  
Preparation Method ◽  
Low Cost ◽  
Ion Beam ◽  
Sample Preparation Method ◽  
Site Specific ◽  
Dual Beam ◽  
Transmission Electron

Abstract Several methods are used to invert samples 180 deg in a dual beam focused ion beam (FIB) system for backside milling by a specific in-situ lift out system or stages. However, most of those methods occupied too much time on FIB systems or requires a specific in-situ lift out system. This paper provides a novel transmission electron microscopy (TEM) sample preparation method to eliminate the curtain effect completely by a combination of backside milling and sample dicing with low cost and less FIB time. The procedures of the TEM pre-thinned sample preparation method using a combination of sample dicing and backside milling are described step by step. From the analysis results, the method has applied successfully to eliminate the curtain effect of dual beam FIB TEM samples for both random and site specific addresses.

Feasibility study of technology-enabled prevention intervention for children and families (Preprint)

2019 ◽  
Author(s):  
Nikki Theofanopoulou ◽  
Katherine Isbister ◽  
Julian Edbrooke-Childs ◽  
Petr Slovák
Keyword(s):  
Emotion Regulation ◽  
Pilot Study ◽  
Low Cost ◽  
Digital Camera ◽  
Well Being ◽  
Structured Interview ◽  
Object A ◽  
Intervention Delivery ◽  
Parents And Children

BACKGROUND A common challenge within psychiatry and prevention science more broadly is the lack of effective, engaging, and scale-able mechanisms to deliver psycho-social interventions for children, especially beyond in-person therapeutic or school-based contexts. Although digital technology has the potential to address these issues, existing research on technology-enabled interventions for families remains limited. OBJECTIVE The aim of this pilot study was to examine the feasibility of in-situ deployments of a low-cost, bespoke prototype, which has been designed to support children’s in-the-moment emotion regulation efforts. This prototype instantiates a novel intervention model that aims to address the existing limitations by delivering the intervention through an interactive object (a ‘smart toy’) sent home with the child, without any prior training necessary for either the child or their carer. This pilot study examined (i) engagement and acceptability of the device in the homes during 1 week deployments; and (ii) qualitative indicators of emotion regulation effects, as reported by parents and children. METHODS In this qualitative study, ten families (altogether 11 children aged 6-10 years) were recruited from three under-privileged communities in the UK. The RA visited participants in their homes to give children the ‘smart toy’ and conduct a semi-structured interview with at least one parent from each family. Children were given the prototype, a discovery book, and a simple digital camera to keep at home for 7-8 days, after which we interviewed each child and their parent about their experience. Thematic analysis guided the identification and organisation of common themes and patterns across the dataset. In addition, the prototypes automatically logged every interaction with the toy throughout the week-long deployments. RESULTS Across all 10 families, parents and children reported that the ‘smart toy’ was incorporated into children’s emotion regulation practices and engaged with naturally in moments children wanted to relax or calm down. Data suggests that children interacted with the toy throughout the duration of the deployment, found the experience enjoyable, and all requested to keep the toy longer. Child emotional connection to the toy—caring for its ‘well-being’—appears to have driven this strong engagement. Parents reported satisfaction with and acceptability of the toy. CONCLUSIONS This is the first known study investigation of the use of object-enabled intervention delivery to support emotion regulation in-situ. The strong engagement and qualitative indications of effects are promising – children were able to use the prototype without any training and incorporated it into their emotion regulation practices during daily challenges. Future work is needed to extend this indicative data with efficacy studies examining the psychological efficacy of the proposed intervention. More broadly, our findings suggest the potential of a technology-enabled shift in how prevention interventions are designed and delivered: empowering children and parents through ‘child-led, situated interventions’, where participants learn through actionable support directly within family life, as opposed to didactic in-person workshops and a subsequent skills application.

scholarly journals Converting copper sulfide to copper with surface sulfur for electrocatalytic alkyne semi-hydrogenation with water

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yongmeng Wu ◽  
Cuibo Liu ◽  
Changhong Wang ◽  
Yifu Yu ◽  
Yanmei Shi ◽  
...  
Keyword(s):  
Binding Energy ◽  
Noble Metal ◽  
Atomic Hydrogen ◽  
Copper Sulfide ◽  
Low Cost ◽  
Water Electrolysis ◽  
Metal Free ◽  
Copper Nanowire

AbstractElectrocatalytic alkyne semi-hydrogenation to alkenes with water as the hydrogen source using a low-cost noble-metal-free catalyst is highly desirable but challenging because of their over-hydrogenation to undesired alkanes. Here, we propose that an ideal catalyst should have the appropriate binding energy with active atomic hydrogen (H*) from water electrolysis and a weaker adsorption with an alkene, thus promoting alkyne semi-hydrogenation and avoiding over-hydrogenation. So, surface sulfur-doped and -adsorbed low-coordinated copper nanowire sponges are designedly synthesized via in situ electroreduction of copper sulfide and enable electrocatalytic alkyne semi-hydrogenation with over 99% selectivity using water as the hydrogen source, outperforming a copper counterpart without surface sulfur. Sulfur anion-hydrated cation (S2−-K+(H2O)n) networks between the surface adsorbed S2− and K+ in the KOH electrolyte boost the production of active H* from water electrolysis. And the trace doping of sulfur weakens the alkene adsorption, avoiding over-hydrogenation. Our catalyst also shows wide substrate scopes, up to 99% alkenes selectivity, good reducible groups compatibility, and easily synthesized deuterated alkenes, highlighting the promising potential of this method.

MOF-derived M-OOH with rich oxygen defects by in-situ electro-oxidation reconstitution for highly efficient oxygen evolution reaction

2021 ◽  
Author(s):  
Zhikai Shi ◽  
Zebin Yu ◽  
Ronghua Jiang ◽  
Jun Huang ◽  
Yanping Hou ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Energy Production ◽  
Low Cost ◽  
Highly Efficient ◽  
Oxygen Defects ◽  
Electro Oxidation

The oxygen evolution reaction (OER) is an important half-reaction in the field of energy production. However, how effectively, simply, and greenly to prepare low-cost OER electrocatalysts remains a problem. Herein,...

scholarly journals Homocoupling of Substituted Benzenes to Symmetrical Biaryls with Mercury(II) in the Presence of Cerium(IV)

1999 ◽  
Vol 23 (7) ◽  
pp. 442-443
Author(s):  
Nasser Iranpoor ◽  
Marzieh Shekarriz
Keyword(s):  
Substituted Benzenes ◽  
High Yields

Homocoupling of substituted benzenes to symmetrical biaryls is achieved with different cerium(IV) compounds such as cerium(IV) triethylammonium nitrate (CTEAN), cerium(IV) pyridinium nitrate (CPN) and Ce(OTf)4 in the presence of HgII in good to high yields.

Regioselective Functionalization of N-Fused Heteroaromatics via FeCl3-Catalyzed Nucleophilic Addition to Activated N-Heterocycles

Synthesis ◽  
2020 ◽  
Author(s):  
Ikyon Kim ◽  
Sung June Kim ◽  
Sunhee Lee
Keyword(s):  
Aromatic Compounds ◽  
Nucleophilic Addition ◽  
Chemical Space ◽  
Wide Range ◽  
Regioselective Functionalization

AbstractBroadening of nitrogen-fused heteroaromatic chemical space such as indolizine and pyrrolo[1,2-a]pyrazine was achieved via FeCl­3-catalyzed nucleophilic addition of these N-fused aromatic compounds to a wide range of azolinium systems generated in situ, leading to novel N-fused heteroaromatic scaffolds with dearomatized N-heterocyclic substituents regioselectively. Nucleophilic addition of indolizines and pyrrolo[1,2-a]pyrazines mainly occurred at the C1 position of the isoquinoliniums and at the C4 site of the quinoliniums.

Fabrication of monodisperse polypyrrole/SBA-15 composite for the selective removal of Cr(Ⅵ) from aqueous solutions

2021 ◽  
Author(s):  
Liang Wang ◽  
Peng Gao ◽  
Mengxin Liu ◽  
Ziqing Huang ◽  
Shixia Lan ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Adsorption Process ◽  
In Situ Polymerization ◽  
Selective Removal ◽  
Factors Affecting

Monodisperse polypyrrole/SBA-15 composite (PPy/SBA-15) was fabricated by in-situ polymerization and used for Cr(Ⅵ) adsorption from aqueous solution. PPy/SBA-15 was characterized by numerous approaches. Factors affecting the Cr(Ⅵ) adsorption process included...

Design of Ionic Liquid 3-Methyl-1-sulfonic Acid Imidazolium Nitrate as Reagent for the Nitration of Aromatic Compounds by in Situ Generation of NO2 in Acidic Media

2012 ◽  
Vol 77 (7) ◽  
pp. 3640-3645 ◽  
Author(s):  
Mohammad A. Zolfigol ◽  
Ardeshir Khazaei ◽  
Ahmad R. Moosavi-Zare ◽  
Abdolkarim Zare ◽  
Hendrik G. Kruger ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Aromatic Compounds ◽  
Sulfonic Acid ◽  
Acidic Media ◽  
In Situ Generation
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