Chemiluminescent Glow Research Articles

USING MATHEMATICAL MODELING TO EVALUATE THE ANTIOXIDANT ACTIVITY OF S-, Se-CONTAINING SPATIALLY HINDERED PHENOLS

In this work, regression analysis was used to evaluate the antioxidant activity of the synthesized S- and Se-containing α-methylbenzylbisphenols in comparison with the industrial antioxidant additive 2,6-ditretbutyl-4-methylphenol under similar conditions. The experimental antioxidant efficiency was calculated from the ratio of the peaks of chemiluminescent glow in vaseline oil at concentrations of 0.025–1% at 200 °C. Based on the results of calculations and experimental data, numerical dependences of the influence of concentrations – x1 (% wt.conc.), electrophilicity x2 on the antioxidant capacity (Y) of the studied additives to lubricating oils and cutting fluids were constructed in the form of nonlinear equations. The behavior of the studied compounds is analyzed and modeled, taking into account the geometric parameters of the molecules for the property under study, depending on the mass concentration. According to the research results, it was confirmed that the introduction of a methyl group into the p-position of the benzene ring of hindered phenol leads to an increase in antioxidant efficiency. The numerical method shows the effectiveness of the use of these additives in comparison with the widely used additive "Agidol-1". The obtained values of the structural parameters of the compounds calculated by the UB3LYP/6-311++G(d,p) method agree with the experimental data (with an accuracy of 81%-98.7%). The effectiveness of sterically hindered phenols is due to the presence of bulky substituents in the o-positions, which optimally shield the hydrogen of the OH group and, accordingly, the low activity of the phenoxyl radical formed in the reaction with peroxide radicals from the inhibitor. The clearly presented dependences show that Se-containing derivatives of α-methylbenzylphenol exhibit greater antioxidant efficiency and are effective inhibitors of lubricating oils and cutting fluids due to the presence of a larger number of active sites in these molecules and, therefore, interrupting a greater number of oxidation chains than molecules with a disulfide bridge.

Chemiluminescence of electronically excited species during the self-ignition of acetylene behind reflected shock waves

Acetylene is an effective additive to various rocket fuels. Acetam, an equilibrium highly concentrated solution of acetylene in liquid ammonia, is a promising fuel for use in liquid−propellant jet engines. To gain insights into the processes occurring in such systems and provide means for predicting their characteristics, the self-ignition of model acetylene−oxygen−argon mixtures is experimentally and theoretically studied. The experiments are performed behind reflected shock waves in a temperature range from 1100 to 1870 K at a total gas concentration of [M] ≈ 1.0 × 10−5 mol/cm3, with chemiluminescence signals from electronically excited C2* (λ ≅ 516 nm), CH* (429 nm), CO2*(363 nm), and OH* (308 nm) recorded. Numerical simulations within the framework of various detailed kinetic mechanisms closely reproduce the measured temperature dependences of the ignition delay time for the tested mixtures, but in some cases fail to satisfactorily describe the time profiles of the emission signals from C2*, CH*, CO2*, and OH*. The performed numerical simulations make it possible to explain the observed characteristic features of the emission profiles of electronically excited C2*, CH*, CO2*, and OH* during the self-ignition of C2H2–O2−Ar mixtures. Sensitivity analysis demonstrates that the existence and characteristics of the preignition stage in the CO2* and OH* emission signals are largely determined by the kinetic behavior of intermediate species, such as the ketene molecule and CH2 radical. Based on the results obtained, a new detailed kinetic mechanism has been proposed for describing processes in the combustion products of acetylene-containing propellants, in particular chemiluminescent glow, which are of considerable interest for the development of new technologies for astronautics and aeronautics.

Arsenal goes aglow for Cyalume

Private equity firm Arsenal Capital Partners will pay $45 million to acquire Cyalume Technologies, a firm best known for its chemiluminescent glow sticks. Invented by American Cyanamid scientists in the 1970s, the sticks are based on a phenyl oxalate ester mixed with hydrogen peroxide and dye. More than two-thirds of Cyalume’s $41 million in sales last year came from chemiluminescent devices and munitions, primarily for military use. The balance was from specialty chemicals for pharmaceuticals, medical devices, and other uses.

A glowing discovery lost on management and NMR night-light

A glowing discovery lost on management “Letters, we get letters, we get stacks and stacks of letters.” This member of the Newscripts gang is showing his age because that is a song lyric from the 1950s “Perry Como Show.” Other notable talents include singing the Cream of Wheat advertising jingle and reciting the introduction to the original “Adventures of Superman” TV show with George Reeves. But back to the letters. Like Perry Como, Newscripts also gets letters, or at least e-mail, and two recent missives were particularly illuminating. Consultant Edwin A. Chandross of Murray Hill, N.J., wrote to say he enjoyed a March 20 C&EN article on chemiluminescence (page 5), and, by the way, he invented the now-ubiquitous chemiluminescent glow sticks serendipitously in the 1960s. Glow sticks are plastic tubes containing a solution of an ester, such as diphenyl oxalate, and a fluorescent dye. Each tube also contains a breakable

Personal Protective Equipment and Simulation: Use of Chemiluminescent Glow Sticks as a Game Changer?

Ensuring the safe, effective management of patients requires efficient processes of care within a smoothly operating system in which highly reliable teams of talented, skilled health care providers are able to use the vast array of high-technology resources and intensive care techniques available. Simulation can play a unique role in exploring and improving the complex perioperative system by proactively identifying latent safety threats and mitigating their damage to ensure that all those who work in this critical health care environment can provide optimal levels of patient care.A panel of five experts from a wide range of institutions was brought together to discuss the added value of simulation-based training for improving systems-based aspects of the perioperative service line. Panelists shared the way in which simulation was demonstrated at their institutions. The themes discussed by each panel member were delineated into four avenues through which simulation-based techniques have been used.Simulation-based techniques are being used in (1) testing new clinical workspaces and facilities before they open to identify potential latent conditions; (2) practicing how to identify the deteriorating patient and escalate care in an effective manner; (3) performing prospective root cause analyses to address system weaknesses leading to sentinel events; and (4) evaluating the efficiency and effectiveness of the electronic health record in the perioperative setting.This focused review of simulation-based interventions to test and improve components of the perioperative microsystem, which includes literature that has emerged since the panel's presentation, highlights the broad-based utility of simulation-based technologies in health care.

Magnesium methoxide-induced chemiluminescent decomposition of bicyclic dioxetanes bearing a 2′-alkoxy-2-hydroxy-1,1′-binaphthyl-7-yl moiety

Bicyclic dioxetanes 2a-c bearing a 2'-alkoxy-2-hydroxy-1,1'-binaphthyl-7-yl moiety were effectively synthesized and their base-induced chemiluminescent decomposition was investigated by the use of alkaline metal (Na(+) and K(+) ) or Mg(2+) alkoxide in MeOH. When 2a-c were treated with tetrabutylammonium fluoride (TBAF) in dimethyl sulfoxide (DMSO) as a reference system, they showed chemiluminescence as a flash of orange light (maximum wavelength λmax (CL) = 573-577 nm) with efficiency Φ(CL) = 6-8 × 10(-2) . On the other hand, for an alkaline metal (Na(+) or K(+) ) alkoxide/MeOH system, 2a-c decomposed slowly to emit a glow of chemiluminescence, the spectra of which were shifted slightly toward red from the TBAF/DMSO system, and Φ(CL) (= 1.4-2.3 × 10(-3) ) was considerably decreased. In addition, Mg(OMe)2 was found to play a characteristic role as a base for the chemiluminescent decomposition of 2a-c through coordination to the intermediary oxidoaryl-substituted dioxetanes 13. Thus, Mg(2+) increased Φ(CL) to more than twice those with Na(+) or K(+) , while it shifted λmax (CL) considerably toward blue (λmax (CL) = 550-566 nm).

Electron Paramagnetic Resonance Spectroscopic Evidence for the Interaction of HAlOH with Water Molecules

The complex HAlOH:(H(2)O) has been detected by matrix-isolation IR spectroscopy. This complex was speculated to be the species responsible for the chemiluminescent glow associated with the explosion of trimethyl aluminum or aluminum grenades in the upper atomosphere. Theoretical studies suggest that HAlOH:(H(2)O)(n) is a critical precursor in the formation of H(2) in the reaction of Al with liquid water. In our study, Al atoms were reacted with mixtures of D(2)O/He or H(2)(17)O/He in an adamantane matrix in a metal-atom reactor, known as a rotating cryostat, maintained at 77 K and at <10(-6) Torr. In addition to DAlOD and HAlOH, which formed from the reaction of Al atoms with adventitious water, EPR analysis of the Al-D(2)O/He reaction mixture from 77 to 290 K showed that HAlOH:(D(2)O) and DAlOD:(D(2)O) formed. The experimental nuclear hyperfine interactions (hfis) for these species were in close agreement with those calculated using the B3LYP density functional method and the 6-311+G(2df,p) basis set. The effect of complexation is to lower the Al hfi of HAlOH and DAlOD by ca. 8%, the H hfi of HAlOH by ca. 28%, and the D hfi of DAlOD by ca. 35%.

Chemiluminescent Properties of Novel Biphenyl Analogue Blue Fluorophores

AbstractFor Abstract see ChemInform Abstract in Full Text.

Chemiluminescent Properties of Novel Biphenyl Analogue Blue Fluorophores

Novel naphthyl-containing biphenyl analogues were prepared by Suzki reaction for the chemiluminescent blue fluorophores. UV-Vis absorption, photoluminescence, chemiluminescence and CIE chromaticities were measured. The fluorophores displayed blue photoluminescence in solution with a maximum intensity around 378-415 nm. Sodium salicylate-catalyzed reaction of them with bis(2-carbopentyloxy-3,5,6-trichlorophenyl)oxalate with hydrogen peroxide provided a strong chemiluminescent red light emission with wavelengths of 398-427 nm; these were similar to the photoluminescent spectra. The chemiluminescent intensity decayed exponentially and the glow of chemiluminescence, which was visible with naked eyes, was maintained for more than 4 h.

Chemiluminescent properties of blue fluorophores containing naphthalene unit

Various conjugated blue fluorophores containing naphthalene moiety in biphenyl analogues were synthesized via Suzuki reaction for the blue chemiluminescent fluorophore. UV–Vis absorption, photoluminescence and chemiluminescence were measured and evaluated. The fluorophores displayed blue photoluminescence in solution with maximum around 375–410 nm. Sodium salicylate-catalyzed reaction of hydrogen peroxide with bis(2-carbopentyloxy-3,5,6-trichlorophenyl) oxalate (CPPO) produced a strong chemiluminescent blue light emission with wavelengths of 398–420 nm in the presence of the fluorophores. The chemiluminescent intensity decayed exponentially and the glow of chemiluminescence maintained for more than 4 h and was visible with naked eye.

Pediatric and young adult exposure to chemiluminescent glow sticks.

Although chemiluminescent plastic rods, commonly called "glow sticks" or "light sticks," are typically considered to be minimally toxic or nontoxic, published data about exposure to these products are scarce. To test our hypothesis that exposure to chemiluminescent products is unlikely to result in significant morbidity or mortality and to describe factors associated with exposure by reviewing reports to our urban poison control center of human exposure to chemiluminescent products. Pediatric and young adult exposure to chemiluminescent products reported between January 1, 2000, and April 1, 2001, to our poison control center were evaluated with regard to demographic group, type of product involved, circumstances of exposure, symptoms, and management. Reported routes of exposure (n = 118) included ingestion (n = 108), ocular (n = 9), and dermal exposure (n = 1). Only patients exposed to chemiluminescent fluid from a leaking container reported symptoms (n = 27). Symptoms were limited to transient irritation of the exposure site, and no systemic toxicity occurred. All adults (n = 4) inadvertently ruptured or swallowed intact light sticks while at a dance club or dance party. Most exposure and all adult exposure occurred on holidays or weekends. Most incidences of exposure to chemiluminescent products involve asymptomatic ingestion of fluid that leaks from glow sticks or ingestion of an intact glow stick. Symptoms occur after exposure to chemiluminescent fluid and consist of transient irritation at the site of exposure. The clustering of reported exposure on weekends and in dance clubs and parties coupled with a lack of occupational or workplace exposure suggest that recreational use is a major contributory factor. Exposure to chemiluminescent products infrequently resulted in symptoms and the symptoms reported were minor. Exposure to chemiluminescent products as described is unlikely to cause significant morbidity or mortality.

Chemiluminescent properties of polymeric blue fluorophores containing diphenylanthracene unit

New conjugated and non-conjugated alternating block copolymers containing 9,10-diphenyl-2-chloroanthracene moieties in the main chain were synthesized via Williamson synthesis for the blue chemiluminescent fluorophore. UV-vis absorption and luminescent characteristics including chemiluminescence were measured and compared with model fluorophore 9,10-bis( p-methoxyphenyl)-2-chloroanthracene. Polymers displayed blue photoluminescence in solution with maximum around 430 nm. Tetramethyl ammonium salicylate-catalyzed reaction of hydrogen peroxide with bis(2-carbopentyloxy-3,5,6-trichlorophenyl)oxalate produced a strong chemiluminescent blue light emission with wavelength of 440 nm in the presence of the polymeric fluorophore. The chemiluminescent intensity decayed exponentially and the glow of chemiluminescence maintained more than l2 h and was visible with naked eye.

Chemiluminescent properties of polyurethane fluorophores containing red and blue chromophore moieties

Polyurethane copolymer fluorophores-containing perylene tetracarboxylic diimide and diphenyl anthracene units were prepared to examine the chemiluminescent properties. The UV–VIS spectrophotometric, photoluminescent and chemiluminescent characteristics were investigated for the monomeric and polymeric fluorophores. The sodium salicylate-catalyzed reaction of bis(2-carbopentyloxy-3,5,6-trichlorophenyl)oxalate with hydrogen peroxide provided a strong chemiluminescent light emission from red to blue color according to the mixing ratio of two chromophore units as analogous to the photoluminescent spectra. Although the chemiluminescent intensity was found to decay biexponentially as a function of measuring time, the chemiluminescent glow lasted for more than 24 h and was visible with the naked eye.

Chemiluminescent properties of copolyesters containing red and blue chromophores

Polyester fluorophores containing red and blue light-emitting chromophore units were prepared by copolycondensation of perylene tetracarboxydiimide and diphenyl anthracene derivative with sebacoyl chloride for the chemiluminescence. The properties of fluorophore polymers were studied by UV–Vis spectrophotometric, photoluminescent and chemiluminescent investigation. The intensities of UV–Vis absorbance, photoluminescence and chemiluminescence spectra appeared to systematically increase as the content of two monomers. The sodium salicylate-catalyzed reaction of bis(2-carbopentyloxy-3,5,6-trichlorophenyl)oxalate with hydrogen peroxide provided a strong chemiluminescent light changing from red to blue according to the content of two chromophore units; these were similar to the photoluminescent spectra. The chemiluminescent intensity was decayed biexponentially, but the glow of chemiluminescence maintained more than 24 h and was visible with the naked eye.

Chemiluminescent properties of perylene-containing polymeric red fluorophores

Perylenetetracarboxylic diimide derivative-containing monomeric and polymeric red fluorophores were prepared for the chemiluminescence. The UV–VIS spectrophotometric, photoluminescent and chemiluminescent characteristics were investigated. Sodium salicylate-catalyzed reaction of them with bis(2-carbopentyloxy-3,5,6-trichlorophenyl)oxalate with hydrogen peroxide provided a strong chemiluminescent red light emission at around 625nm; these were similar to the photoluminescent spectra. The chemiluminescent intensity was decayed exponentially, but the glow of chemiluminescence maintained more than 18h and was visible with naked eye.

Ignition of CO/H 2/N 2 versus heated air in counterflow: experimental and modeling results

Nonpremixed ignition in counterflowing CO/H 2 vs. heated air jets is experimentally and computationally investigated. The experiments confirm the numerical modeling observation of the existence of three ignition regimes as a function of the hydrogen concentration. In all three regimes, we first detect experimentally the onset of chemiluminescent glow due to excited CO 2 followed by flame ignition, as the temperature of the air jet is raised gradually. The temperature extent of the glow regime, however, is progressively reduced with increasing hydrogen addition; no glow is detected for H 2 concentrations in excess of ∼73%. The temperatures for glow onset and flame ignition are represented by the boundary air temperatures for each threshold. The variation of these temperatures with system pressure and flow strain rate is explored, for pressures between 0.16 and 5 atm, and strain rates of 100 to 600 s −1. The pressure variation is found to result in three p-T ignition limits, similar to the ignition limits observed in the H 2/O 2 system. This similarity is also observed on the effects of aerodynamic transport on ignition: within the second limit the ignition temperatures are found to be essentially insensitive to flow strain rate, whereas the other two limits are significantly affected by strain. The transport insensitivity is maintained even in the limit of very low H 2 concentrations, where an analogous H 2/N 2 mixture would fail to ignite. This behavior is explained computationally by the replacement of the shift reaction OH + H 2 → H 2O + H with the reaction CO + OH → CO 2 + H, thereby minimizing the effect of diminishing H 2 concentration. The experimental data are found to agree well with the calculated results, although discrepancies are noted in modeling the onset of chemiluminescence and its response to pressure variations.

A new airglow layer in the stratosphere

A new airglow layer has been observed arising from the 40 to 60 km level in the stratosphere. The upper portion of this layer was first measured by the WINDII instrument when the Upper Atmospheric Research Satellite was rotated in roll angle so the field of view measured down to 60 km in January, 1994. The main hydroxyl airglow layer at 85 km is measured with the WINDII filter channel at 730 nm. After the April roll angle increase, a continuum emission layer was observed below 70 km on numerous images. It is proposed that this emission originates from excited NO2 created from the reaction of O3 with NO. This new airglow layer is peaked around 45 km about 1 hour after sunset. The chemiluminescent glow from this reaction is well known in the laboratory and is used in balloon instruments for the measurement of nitric oxide in the stratosphere and troposphere.

REMOTE PLASMA COPPER CVD WITH HYDROGEN AND OXYGEN ATOMS

Thin copper films have been deposited by the room temperature reaction of gaseous copper (II) hexa-fluoroacetylacetonate [Cu(hfa)2] with hydrogen atoms produced in a remote discharge tube. The resulting films are conductive and adherent on a wide variety of substrates. Copper atoms have been observed and measured in the gas phase and were found by atomic absorption spectroscopy to have a maximum concentration of approximately 1011 atoms/cc in the mixing/reaction zone. The reaction of Cu(hfa)2 with oxygen atoms was also studied. The reaction again resulted in the deposition of a film and in addition a green chemiluminescent glow was observed which was identified as due to the gaseous diatomic CuF molecule. Copper atoms were also observed by absorption spectroscopy within this chemiluminescent reaction with oxygen atoms. The copper atom concentration was found to be approximately the same as that found with the H-atom reaction. The copper atom concentrations and the relative emission intensities of CuF were studied as a function of time and position to gain insight into the deposition process.

Copper Film Deposition Using H and O Atoms

ABSTRACTThe formation of thin copper films by H-atom reaction with Cu(FOD)2 and Cu(HFA)2 has been demonstrated at near room temperature. Oxygen atoms have now also been reacted with these β-diketonate copper complexes, producing films of copper oxide which can be readily reduced by subsequent treatment with H-atoms. The thin copper films produced are conductive and highly adherent. The oxygen atom reaction with the copper complex produces a visible chemiluminescent glow, yielding information on the nature of the reaction process.

Surface effects in the gas-phase oxidation of carbon monoxide

The oxidation of carbon monoxide, like that of hydrogen, is a text-book example of a branched-chain chemical reaction. It shows the classical phenomena including first and second explosion limits in the reactant pressure-vessel temperature (p -Ta ) diagram. Two extra patterns of reaction are also observed in both closed and open (flow) systems. These are steady chemiluminescent glow (from the product CO2 ) and a pulsed, oscillatory glow.These are found within a separate p -Ta region bounded by dark reaction at low temperature and ignition at high temperature.Which of these two patterns is observed in any given experiment depends strongly on the previous history of the reactor. Oscillatory glow can be generated at will by pretreatment of the surface with chloropicrin, a known inhibitor of CO oxidation. In clean systems, careful procedures and conditioning of the reactor surface is necessary. In the first experiments in a fresh vessel steady glow is observed. Subsequent experiments yield oscillatory glow, but eventually stedy behaviour returns.In open systems, this conditioning is more easily acheived but is still important. Furthermore the observed extents of self-heating accompanying the slow exothermic reaction are greater than those predicted on the basis of any solely gas-phase mechanism.The influence of the surface on the water-gas shift equilibriumH2 O + CO [math] H2 + CO2 is believed to hold the key.