Dissociative Photoionization of 1,3-Dioxolane
Poster Number
3a
Introduction/Abstract
1,3-Dioxolane (C2H6O2) is a small cyclic organic molecule that contains more than 40% oxygen by mass. Due to its high oxygen content 1,3-dioxolane and its derivatives are promising alternative fuel components and fuel additives. Besides fuel development, uses of 1,3-dioxolane can be found in organic synthesis and polymer chemistry as well. In spite of its various applications and potential use in alternative fuels, accurate data on the dissociative photoionization and energetics of 1,3-dioxolane is not available in recent literature. Relevant publications date back to more than forty years ago and only propose possible mechanisms for the dissociation process, without providing any proof or further insight.
Purpose
The lack of detailed information in recent scientific literature provided the main motivation to study the dissociative photoionization of 1,3-dioxolane. The main purpose of this work is to fill this informational gap by gaining detailed information on the dissociation process, including reaction mechanisms, energetics, and structural information of the fragments involved.
Method
The dissociative photoionization of 1,3-dioxolane was studied by photoelectron photoion coincidence (or shortly PEPICO) spectroscopy at the vacuum ultraviolet (VUV) beamline of the Swiss Light Source (Villigen, Switzerland). Gas phase sample molecules were ionized by finely tuned VUV radiation with high energy resolution. Photoelectrons and photoions produced upon ionization were extracted from the ionization region and detected at opposite ends of the experimental setup in coincidence with each other, thus providing an opportunity for highly accurate energy selection of the photoions. The experimental data (relative ion abundances as a function of photon energy) was modeled using the Rice‒Ramsperger‒Kassel‒Marcus (RRKM) theory of unimolecular dissociations in order to discover all possible dissociation pathways involved in the studied process. Minima and transition state structures were located by ab initio quantum chemical calculations using the Gaussian 09 suite of programs.
Results
In accordance with prior literature, three fragment ions (m/z = 73, 45 and 44) were observed as products of the dissociative photoionization of 1,3-dioxolane. Their relative abundances were plotted as a function of photon energy, obtaining the so-called breakdown diagram in the photon energy range of 9.65 – 13.50 eV. RRKM modeling of the experimental data showed that there are two different reactions involved in the formation of each ion, hence a total of six different dissociation pathways were identified alongside with the so-called appearance energies of these channels. Three of these six reactions are newly discovered and have not been described before as being involved in the dissociation of 1,3-dioxolane.
Significance
This research project provided information in detail not previously available on the dissociative photoionization of 1,3-dioxolane, a process not completely understood and described in prior scientific literature. Our findings resulted in significant additions to the already available information on the studied process and proposed corrections where it seems to be necessary. The results of this research can be of benefit for several fields which require detailed description of gas phase unimolecular dissociations, such as fuel development, combustion chemistry, atmospheric chemistry, and gas phase ion chemistry.
Location
DeRosa University Center
Format
Poster Presentation
Poster Session
Afternoon 1pm-3pm
Dissociative Photoionization of 1,3-Dioxolane
DeRosa University Center
1,3-Dioxolane (C2H6O2) is a small cyclic organic molecule that contains more than 40% oxygen by mass. Due to its high oxygen content 1,3-dioxolane and its derivatives are promising alternative fuel components and fuel additives. Besides fuel development, uses of 1,3-dioxolane can be found in organic synthesis and polymer chemistry as well. In spite of its various applications and potential use in alternative fuels, accurate data on the dissociative photoionization and energetics of 1,3-dioxolane is not available in recent literature. Relevant publications date back to more than forty years ago and only propose possible mechanisms for the dissociation process, without providing any proof or further insight.
