scholarly journals Enabling the Rearrangement of Unactivated Allenes to 1,3-Dienes by Use of a Palladium (0)/Boric Acid System

Synthesis ◽  
2018 ◽  
Vol 50 (12) ◽  
pp. 2329-2336 ◽  
Author(s):  
Marc Kimber ◽  
Yassir Al-Jawaheri ◽  
Matthew Turner
Keyword(s):  
Boric Acid ◽  
Flow Injection ◽  
Acid System ◽  
Palladium Hydride ◽  
Hydride Complex ◽  
Direct Sample

A redox neutral rearrangement of an allene to a 1,3-diene by means of a unique palladium hydride complex is reported. The palladium hydride complex is generated from a simple Pd0 source and boric acid [B(OH)3], which is typically identified as a waste by-product of the Suzuki–Miyaura reaction. A mechanism for this transformation using this novel palladium hydride complex is presented; using a direct sample loop and flow injection ESI-HRMS analysis we have detected and identified key π-allylpalladium complexes that support the addition of the palladium hydride complex to the allene.

The potassium fluoride–boric acid system. Hydrogen bonding in KF·H3BO3

1981 ◽  
pp. 783-787 ◽  
Author(s):  
John Emsley ◽  
Victor Gold ◽  
Jeremy Lucas ◽  
Richard E. Overill
Keyword(s):  
Hydrogen Bonding ◽  
Boric Acid ◽  
Potassium Fluoride ◽  
Acid System

Flow-injection determination of boric acid concentration with conductometric detection

2018 ◽  
Vol 84 (12) ◽  
pp. 20-24
Author(s):  
V. S. Gursky ◽  
E. Yu. Kharitonova
Keyword(s):  
Boric Acid ◽  
Flow Injection ◽  
Nuclear Power ◽  
Sample Volume ◽  
Primary Circuit ◽  
Acid Complex ◽  
Donnan Dialysis ◽  
Fixed Sample ◽  
Conductometric Detection

The flow-injection determination of boric acid with conductometric detection in technological environments of the primary circuit of WWER-type nuclear power plant is described. The method consists in periodical dosing a fixed sample volume into the flow of the mannitol solution. As a of the Formation of an anionic boric acid complex with mannitol and equivalent amount of hydroxonium ions, results in an abrupt increase in the electrical conductivity, which is recorded by a conductometric detector. The hydraulic and measuring circuits of the analyzer are implemented using standard ionochromatographic equipment. It is shown than in the concentration range of the analyte 1 – 16 g/liter, the correcting additives of ammonium and potassium hydroxides do not interfere with the results of the analysis. To eliminate the interfering effect of correcting additives at low concentrations of boric acid (0.2 – 1.0 g/liter) we propose to use a Donnan dialysis through a cation exchange membrane. Optimal conditions of the analysis are specified and the metrological characteristics are determined. At a concentration of boric acid of 0.2 g/liter, the standard deviation does not exceed 2%.

Automated Flow-Injection Pseudotitration of Boric Acid

1985 ◽  
Vol 74 (8) ◽  
pp. 886-888 ◽  
Author(s):  
Paraskevi I. Anagnostopoulou ◽  
Michael A. Koupparis
Keyword(s):  
Boric Acid ◽  
Flow Injection

Flow Injection Preconcentration Coupled with Direct Sample Insertion for Inductively Coupled Plasma Atomic Emission Spectrometry

1991 ◽  
Vol 45 (10) ◽  
pp. 1581-1586 ◽  
Author(s):  
P. Moss ◽  
E. D. Salin
Keyword(s):  
Detection Limit ◽  
Flow Injection ◽  
Inductively Coupled Plasma ◽  
Atomic Emission ◽  
Atomic Emission Spectrometry ◽  
Emission Spectrometry ◽  
Plasma Atomic Emission ◽  
Plasma Atomic Emission Spectrometry ◽  
Inductively Coupled ◽  
Direct Sample

A flow injection (FI) preconcentration system has been coupled with a direct sample insertion (DSI) system for inductively coupled plasma atomic emission spectrometry (ICP-AES). The FI system provides a preconcentration factor of approximately 30. The DSI detection limit improvement, as compared to conventional nebulization detection limits, is element specific and ranges between 10 and 130 when a cup specifically designed for liquid work is used. The FI-DSI hybrid provides detection limit improvements ranging between 140 and 1200 for the elements tested—Cu, Pb, and Zn. Precision of the FI-DSI-ICP system averages 4% RSD for these three elements. FI processing time is 6.0 minutes with the use of 5-mL injection volumes. The system offers considerable potential for further improvement by increasing the injection volume and improving the interface to the DSI.

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