State-Dependent Solvation of Pyrene in Supercritical CO2

Rice, Jeanette K.; Niemeyer, Emily D.; Dunbar, Richard A.; Bright, Frank V.

doi:10.1021/ja00126a023

Cited by 60 publications

(89 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In supercritical C0 2 the typical, maximal local density enhancement is on the order of 230% for pyrene. 46 Clearly, we observe a much greater degree of local density enhancement in SCW. This is likely due in part to the ability of water to hydrogen bond more with itself and/or due to the more polarizable nature of water relative to C0 2 .…”

Section: Resultsmentioning

confidence: 67%

“…Figure 5 presents the recovered I,/I 3 ratios, determined as previously described, for pyrene in water as a function of reduced density from 26.6 to 398. The 7r* term, in turn, has been shown to depend linearly on the dielectric cross term, f(e, n 2 ) where c and d are constants, e is the solvent dielectric constant, and n is the solvent refractive index: 46 - …”

Section: Resultsmentioning

confidence: 99%

“…Pyrene is an ideal solute because its photophysics are well-known and it has been thoroughly studied in a variety of media, 4350 including other supercritical fluids. 46 " 50 However, there are many special experimental considerations that must be taken into account when making these measurements in supercritical alkanes. Due to the high temperature needed to generate a supercritical alkane (T c (pentane) = 196.6 °C; T c (hexane) = 234.4 °C; T c (heptane) = 267.30 °C), the solute must be stable at harsh temperatures with minimal spectral broadening.…”

Section: Discussionmentioning

confidence: 99%

“…43 This approach has been used previously in supercritical C0 2 to determine the degree of local density augmentation over a broad density region. 46,47 However, because of the nature of SCW, these measurements become significantly more challenging because of temperatureinduced broadening of the pyrene emission spectrum. Finally, one must carefully deoxygenate fully the pyrene/water solutions to minimize solute oxidation.…”

Section: -4mentioning

confidence: 99%

“…46 Experiments were not conducted below p, = 0.5 because of poor signal-to-noise (S/N). The density and dielectric constant of water as a function of temperature and pressure were calculated using a simple, complete equation of state as described by Pitzer and…”

Section: Instrumentationmentioning

confidence: 99%

See 4 more Smart Citations

Summer Research Program - 1996 Summer Research Extension Program. Volume 4B, Wright Laboratory

Moore¹

1996

View full text Add to dashboard Cite

AGENCY USE ONLY (Leave blank)2. REPORT DATE December, 1996 _ AFRL-SR-BL-TR-00- ABSTRACT (Maximum 200 words)The United States Air Force Summer Research Program (SRP) is designed to introduce university, college, and technical institute faculty members to Air Force research. This is accomplished by the faculty members, graduate students, and high school students being selected on a nationally advertised competitive basis during the summer intersession period to perfora research at Air Force Research Laboratory (AFRL) Technical Directorates and Air Force Air Logistics Centers (ALC). AFOSR also offers its research associates (faculty only) an opportunity, under the Summer Research Extension Program (SREP), to continue their AFOSR-sponsored research at their home institutions through the award of research grants. This volume consists of a listing of the participants for the SREP and the technical report from each participant working at the AI Wright Laboratory. SUBJECT TERMS GENERAL INSTRUCTIONS FOR COMPLETING SF 298The Report Documentation Page (RDP) is used in announcing and cataloging reports. It is important that this information be consistent with the rest of the report, particularly the cover and title page. Instructions for filling in each block of the form follow. It is important to stay within the lines to meet optical scanning requirements. Block 1. Agency Use Only (Leave blank).Block 2. Report Date. Full publication date including day, month, and year, if available (e.g. 1 Jan 88). Must cite at least the year.Block 3. Type of Report and Dates Covered. State whether report is interim, final, etc. If applicable, enter inclusive report dates (e.g. 10Jun87-30Jun88).Block 4. Title and Subtitle. A title is taken from the part of the report that provides the most meaningful and complete information. When a report is prepared in more than one volume, repeat the primary title, add volume number, and include subtitle for the specific volume. On classified documents enter the title classification in parentheses.Block 5. Funding Numbers. To include contract and grant numbers; may include program element number(s), project number(s), task number(s), and work unit number(s). Use the following labels:Block 6. Author(s). Name(s) of person(s) responsible for writing the report, performing the research, or credited with the content of the report. If editor or compiler, this should follow the name(s). Block 7.Performing Organization Name(s) and Address(es). Self-explanatory.Block 8. Performing Organization Report Number. Enter the unique alphanumeric report number(s) assigned by the organization performing the report.Block 9. Sponsoring/Monitoring Agency Name(s) and Address(es). Self-explanatory. PREFACEThis volume is part of a five-volume set that summarizes the research of participants in the 1996 AFOSR Summer Research Extension Program (SREP.) The current volume, Volume 1 of 5, presents the final reports of SREP participants at Armstrong Laboratory. Volume 1 also includes the Management Report.Reports presented in t...

show abstract

Section: Resultsmentioning

confidence: 67%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: -4mentioning

confidence: 99%

Section: Instrumentationmentioning

confidence: 99%

See 3 more Smart Citations

Summer Research Program - 1996 Summer Research Extension Program. Volume 4B, Wright Laboratory

Moore¹

1996

View full text Add to dashboard Cite

show abstract

Fluorescence Spectroscopy to Probe Ionic Liquid‐Based Systems

Pandey

Trivedi

Pandey³

2018

Encyclopedia of Analytical Chemistry

View full text Add to dashboard Cite

Owing to its inherent sensitivity coupled with multidimensionality, fluorescence spectroscopy has established itself as a versatile tool to investigate complex chemical systems in analytical chemistry. Ionic liquids, for the last couple of decades or so, have emerged as intriguing modern materials in science and technology that display an array of useful and sometimes unconventional features. Steady‐state fluorescence intensity and anisotropy and time‐resolved excited‐state emission intensity and anisotropy decays along with other advanced fluorescence techniques have been employed effectively to analyze, characterize, and explore ionic liquids and ionic liquid‐based systems. The extent of dipolarity afforded by ionic liquids as well as cosolvent/supercritical fluid‐added ionic liquid systems is readily manifested through the response of judiciously selected fluorescence polarity probes. Transient solvation measurements carried out by means of time‐resolved fluorescence measurements are particularly powerful for their ability to parameterize the kinetics of the solvation process within ionic liquids. Dynamic Stokes' shift of appropriate fluorescence probes reveals the presence of several components, thus highlighting the complexity of solvation within ionic liquids and ionic liquid‐based media. Various fluorescence spectroscopic tools are used to establish and characterize macromolecular (surfactant and polymer) and dye aggregation within ionic liquids and ionic liquid‐based media along with aggregation of surface‐active ionic liquids (SAILs) in water.

show abstract

UV, EPR, X‐ray and Related Spectroscopic Techniques

Yonker¹,

Linehan²,

Fulton³

1999

Chemical Synthesis Using Supercritical Fluids

View full text Add to dashboard Cite

The techniques described in Chapters 3.1 and 3.2 provide information on a molecular level about solute structure, solution dynamics and chemistries in SCFs. The goal of this chapter is to briefly discuss other spectroscopic techniques applied to SCFs which can be used to determine solution structure or the effects of pressure and temperature on reactions in these solvent systems. An overview of this type, by its nature, can not be considered inclusive, but it is hoped to give future practitioners in the field a reasonable expectation of the type of molecular-level information that different spectroscopic techniques provide under SCF conditions. UV-VisUV-Vis spectroscopy of compounds dissolved in SCFs has been used to determine solvent structure [l-61, solute solubilities [7,8], solid matrix changes [9, lo], and reaction kinetics [ll-161. UV-Vis is often the spectroscopic technique of first choice because many solute molecules of interest have an observable absorption band which can be used for identification and quantitation.In the simplest UV-Vis SCF experiment a pressure vessel (stainless steel or other high pressure metal alloy) is fitted with an inlet (and an outlet) connection for high-pressure tubing and high pressure windows (quartz, sapphire, or diamond). The relative strength of the window materials is diamond > sapphire > quartz. The pressure limits of the cell design depend on the window material and the area of the unsupported window exposed to the fluid pressure. The typical UV cutoff wavelengths for these materials are: sapphire -1500A, quartz -2100 A, and diamond type I1 -2600 A. Many different cell designs have been reported in the literature. A typical high pressure cell design is shown in Figure 3.3-1. The pressure seal between the sapphire window and the cell body is made with a gold plated metal V-ring. The path length is typically 2.5 cm and the cell volume is 3-4 mL. The sapphire windows are 1 cm thick and 2.5 cm in diameter. Common, high-pressure UV-Vis spectroscopy

show abstract

State-Dependent Solvation of Pyrene in Supercritical CO2

Cited by 60 publications

References 0 publications

Summer Research Program - 1996 Summer Research Extension Program. Volume 4B, Wright Laboratory

Summer Research Program - 1996 Summer Research Extension Program. Volume 4B, Wright Laboratory

Fluorescence Spectroscopy to Probe Ionic Liquid‐Based Systems

UV, EPR, X‐ray and Related Spectroscopic Techniques

Contact Info

Product

Resources

About