Oligomeric carbon and siloxane series have been observed by matrix-assisted laser desorption/ionisation mass spectrometry (MALDI-MS), during the analysis of the dichloromethane (DCM)-soluble fractions of condensable material recovered from fuel-rich flames. Laser desorption (LD) spectra showed a pattern of oligomeric dimethyl-siloxane structures with a spacing of 74 u. The siloxane series appears to have originated as contamination of samples by silicone oil used to lubricate connections of polymer tubing. This was confirmed by extracting silicone tubing and silicone grease with DCM followed by MALDI-MS analysis. A series of peaks with a mass spacing of 24 u was also observed, superimposed on the continuum of unresolved organic ions. This oligomeric series appears to correspond to polycyclic aromatics separated by (mainly) ethylene bridges. Thus LD-MS appears to have revealed a series of soot precursors, intermediate between polycyclic aromatics and particulate soot, which was not detected by MALDI-MS. More detailed work is necessary to define these species with precision.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1002/rcm.1337 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Urea enhances the yield and quality of bio-oil produced from corncob through pyrolysis.
Sci Rep
January 2025
Department of Chemistry, Usmanu Danfodiyo University, Sokoto, Nigeria.
As global demand for fossil fuels rises amidst depleting reserves and environmental concerns, exploring sustainable and renewable energy sources has become imperative. This study investigated the pyrolysis of corncob, a widely available agricultural waste, using urea as a catalyst to enhance bio-oil production. The aim was to determine the optimum urea concentration and pyrolysis temperature for bio-oil yield from corncob.
View Article and Find Full Text PDFCatalytic Asymmetric Dehydrogenative Si-H/X-H Coupling toward Si-Stereogenic Silanes.
Acc Chem Res
January 2025
Shenzhen Grubbs Institute and Department of Chemistry, Shenzhen Key Laboratory of Small Molecule Drug Discovery and Synthesis, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China.
ConspectusChiral organosilicon compounds bearing a Si-stereogenic center have attracted increasing attention in various scientific communities and appear to be a topic of high current relevance in modern organic chemistry, given their versatile utility as chiral building blocks, chiral reagents, chiral auxiliaries, and chiral catalysts. Historically, access to these non-natural Si-stereogenic silanes mainly relies on resolution, whereas their asymmetric synthetic methods dramatically lagged compared to their carbon counterparts. Over the past two decades, transition-metal-catalyzed desymmetrization of prochiral organosilanes has emerged as an effective tool for the synthesis of enantioenriched Si-stereogenic silanes.
View Article and Find Full Text PDFInitial experience of a novel ureteral silicon-covered metallic mesh stent in malignant ureteric obstruction: a single-center retrospective study.
BMC Urol
December 2024
Department of Urology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu, Seoul, 06351, Korea.
Background: This study aimed to investigate initial experiences and outcomes of a retrograde inserted new silicone-covered metallic ureteric stent (Urexel™) for malignant ureteric obstruction.
Methods: We retrospectively reviewed the medical records for 12 consecutive patients who underwent Urexel™ stent placement for malignant ureteric obstruction from March 2020 to March 2021. The Urexel™ stent is a segmental metallic ureteric stent composed of a nitinol mesh covered with a silicone membrane.
[Efficacy of wound exclusion combined with silicone tube bicanalicular intubation in the treatment of pigmented nevi of the lacrimal punctum].
Zhonghua Yan Ke Za Zhi
December 2024
Department of Ophthalmology, Zhejiang Provincial People's Hospital (People's Hospital of Hangzhou Medical College), Hangzhou310004, China.
Article Synopsis
- A total of 15 patients (5 men, 10 women) underwent the procedure, which involved excising the nevus while placing a silicone tube to support the area; surgeries lasted about 22 minutes on average.
- Post-surgery results showed no recurrence of nevi, healthy healing with normal eyelid appearance, and no significant complications observed during follow-up periods ranging from 6 months to 2 years.
Aggregation-Induced Emission Properties of Atypical Aliphatic-Chain-Linked Siloxanes-Containing Phosphonate Esters.
Chem Asian J
November 2024
School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, P. R. China.
Phosphonate compounds have been proposed as atypical chromophores, but their luminescence properties, especially in combination with flexible aliphatic chains, remain underexplored. In this study, we have synthesized a series of novel siloxane-containing phosphonate esters as organofluorophores through a catalyst-free, one-pot Kabachnik-Fields (K-F) reaction. This reaction involved acetone, cyclohexanone, or cyclopentanone, with siloxanes containing aliphatic amines and phosphonate diesters as reactants.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!