Anolis whitemani

Number of Pages: 2Integrative BiologyGeological Science

Direct Access to β-Fluorinated Aldehydes by Nitrite-Modified Wacker Oxidation

An aldehyde-selective Wacker-type oxidation of allylic fluorides proceeds with a nitrite catalyst. The method represents a direct route to prepare β-fluorinated aldehydes. Allylic fluorides bearing a variety of functional groups are transformed in high yield and very high regioselectivity. Additionally, the unpurified aldehyde products serve as versatile intermediates, thus enabling access to a diverse array of fluorinated building blocks. Preliminary mechanistic investigations suggest that inductive effects have a strong influence on the rate and regioselectivity of the oxidation

Spectroscopic characterization of model compounds, reactants, and byproducts connected with an isocyanate production chain

Aromatic amines and amine hydrochloride salts play an important part in certain large-scale isocyanate production chains. For the first time, via a combination of periodic-DFT calculations, infrared spectroscopy, and inelastic neutron scattering, this work provides a comprehensive vibrational assignment of 4-benzylaniline (C6H4CH2C6H4NH2), 4,4′-methylenedianiline (H2NC6H4CH2C6H4NH2), and their associated amine hydrochloride salts. Deuterated analogues are additionally utilized to assist vibrational assignments. The heightened awareness of vibrational transitions for these technically relevant reagents and byproducts provides the opportunity to apply infrared spectroscopy as an in-line diagnostic tool within the industrial-scale process operation

A questionnaire elicitation of surgeons' belief about learning within a surgical trial

PMID: 23145113 [PubMed - indexed for MEDLINE] PMCID: PMC3493499 Free PMC ArticlePeer reviewedPublisher PD

Direct Access to β-Fluorinated Aldehydes by Nitrite-Modified Wacker Oxidation

An aldehyde-selective Wacker-type oxidation of allylic fluorides proceeds with a nitrite catalyst. The method represents a direct route to prepare β-fluorinated aldehydes. Allylic fluorides bearing a variety of functional groups are transformed in high yield and very high regioselectivity. Additionally, the unpurified aldehyde products serve as versatile intermediates, thus enabling access to a diverse array of fluorinated building blocks. Preliminary mechanistic investigations suggest that inductive effects have a strong influence on the rate and regioselectivity of the oxidation

Otterbein Miscellany , May 1970

https://digitalcommons.otterbein.edu/miscellany/1018/thumbnail.jp

Emissions of biogenic volatile organic compounds and subsequent photochemical production of secondary organic aerosol in mesocosm studies of temperate and tropical plant species

Silver birch (Betula pendula) and three Southeast Asian tropical plant species (Ficus cyathistipula, Ficus benjamina and Caryota millis) from the pantropical fig and palm genera were grown in a purpose-built and environment-controlled whole-tree chamber. The volatile organic compounds emitted from these trees were characterised and fed into a linked photochemical reaction chamber where they underwent photo-oxidation under a range of controlled conditions (relative humidity or RH ~65–89%, volatile organic compound-to-NOx or VOC / NOx ~3–9 and NOx ~2 ppbV). Both the gas phase and the aerosol phase of the reaction chamber were monitored in detail using a comprehensive suite of on-line and off-line chemical and physical measurement techniques. Silver birch was found to be a high monoterpene and sesquiterpene but low isoprene emitter, and its emissions were observed to produce measurable amounts of secondary organic aerosol (SOA) via both nucleation and condensation onto pre-existing seed aerosol (YSOA 26–39%). In contrast, all three tropical species were found to be high isoprene emitters with trace emissions of monoterpenes and sesquiterpenes. In tropical plant experiments without seed aerosol there was no measurable SOA nucleation, but aerosol mass was shown to increase when seed aerosol was present. Although principally isoprene emitting, the aerosol mass produced from tropical fig was mostly consistent (i.e. in 78 out of 120 aerosol mass calculations using plausible parameter sets of various precursor specific yields) with condensation of photo-oxidation products of the minor volatile organic compounds (VOCs) co-emitted; no significant aerosol yield from condensation of isoprene oxidation products was required in the interpretations of the experimental results. This finding is in line with previous reports of organic aerosol loadings consistent with production from minor biogenic VOCs co-emitted with isoprene in principally isoprene-emitting landscapes in Southeast Asia. Moreover, in general the amount of aerosol mass produced from the emissions of the principally isoprene-emitting plants was less than would be expected from published single-VOC experiments, if co-emitted species were solely responsible for the final SOA mass. Interpretation of the results obtained from the fig data sets leaves room for a potential role for isoprene in inhibiting SOA formation under certain ambient atmospheric conditions, although instrumental and experimental constraints impose a level of caution in the interpretation of the results. Concomitant gas- and aerosol-phase composition measurements also provide a detailed overview of numerous key oxidation mechanisms at work within the systems studied, and their combined analysis provides insight into the nature of the SOA formed