scholarly journals A structure activity relationship for ring closure reactions in unsaturated alkylperoxy radicals

2021 ◽  
Author(s):  
Luc Vereecken ◽  
Giang Vu ◽  
Andreas Wahner ◽  
Astrid Kiendler-Scharr ◽  
Hue Thi Minh Nguyen
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Structure Activity Relationship ◽  
Ring Closure ◽  
Activity Relationship ◽  
Peroxy Radicals ◽  
Important Class ◽  
Structure Activity ◽  
Volatile Organic ◽  
Alkylperoxy Radicals

Terpenoids are an important class of multi-unsaturated volatile organic compounds emitted to the atmosphere. During their oxidation in the troposphere, unsaturated peroxy radicals are formed, which may undergo ring closure...

Carbohydrazide analogues: a review of synthesis and biological activities

2021 ◽  
Vol 21 ◽  
Author(s):  
Ebuka Leonard Onyeyilim ◽  
Mercy Amarachi Ezeokonkwo ◽  
David Izuchukwu Ugwu ◽  
Chiamaka Peace Uzoewulu ◽  
Florence Uchenna Eze ◽  
...  
Keyword(s):  
Organic Chemistry ◽  
Inorganic Chemistry ◽  
Schiff Bases ◽  
Bioactive Compounds ◽  
Biological Activities ◽  
Structure Activity Relationship ◽  
Activity Relationship ◽  
Important Class ◽  
Synthetic Route ◽  
Structure Activity

: Carbohydrazides and their Schiff bases are important class of heterocycles that are not only employed in the area of organic chemistry, but also have tremendous applications in physical and inorganic chemistry. A series of potential bioactive compounds, containing carbohydrazide functionality and their hydrazone derivatives have been synthesized and screened for antibacterial, anticancer, antifungal and anti-inflammatory etc. This brief review discloses some synthetic route to so many reported carbohydrazides, their Schiff bases, their biological activities and their structure activity relationship.

scholarly journals Radical chemistry at night: comparisons between observed and modelled HO<sub>x</sub>, NO<sub>3</sub> and N<sub>2</sub>O<sub>5</sub> during the RONOCO project

2014 ◽  
Vol 14 (3) ◽  
pp. 1299-1321 ◽  
Author(s):  
D. Stone ◽  
M. J. Evans ◽  
H. Walker ◽  
T. Ingham ◽  
S. Vaughan ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Limit Of Detection ◽  
Chain Model ◽  
Peroxy Radicals ◽  
Model Simulations ◽  
Airborne Measurements ◽  
Heterogeneous Processes ◽  
Volatile Organic ◽  
The Uk

Abstract. The RONOCO (ROle of Nighttime chemistry in controlling the Oxidising Capacity of the AtmOsphere) aircraft campaign during July 2010 and January 2011 made observations of OH, HO2, NO3, N2O5 and a number of supporting measurements at night over the UK, and reflects the first simultaneous airborne measurements of these species. We compare the observed concentrations of these short-lived species with those calculated by a box model constrained by the concentrations of the longer lived species using a detailed chemical scheme. OH concentrations were below the limit of detection, consistent with model predictions. The model systematically underpredicts HO2 by ~200% and overpredicts NO3 and N2O5 by around 80 and 50%, respectively. Cycling between NO3 and N2O5 is fast and thus we define the NO3x (NO3x=NO3+N2O5) family. Production of NO3x is overwhelmingly dominated by the reaction of NO2 with O3, whereas its loss is dominated by aerosol uptake of N2O5, with NO3+VOCs (volatile organic compounds) and NO3+RO2 playing smaller roles. The production of HOx and ROx radicals is mainly due to the reaction of NO3 with VOCs. The loss of these radicals occurs through a combination of HO2+RO2 reactions, heterogeneous processes and production of HNO3 from OH+NO2, with radical propagation primarily achieved through reactions of NO3 with peroxy radicals. Thus NO3 at night plays a similar role to both OH and NO during the day in that it both initiates ROx radical production and acts to propagate the tropospheric oxidation chain. Model sensitivity to the N2O5 aerosol uptake coefficient (γN2O5) is discussed and we find that a value of γN2O5=0.05 improves model simulations for NO3 and N2O5, but that these improvements are at the expense of model success for HO2. Improvements to model simulations for HO2, NO3 and N2O5 can be realised simultaneously on inclusion of additional unsaturated volatile organic compounds, however the nature of these compounds is extremely uncertain.

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