scholarly journals A Comparison between the Rate of Reaction of Nitric Oxide in the Gas Phase and in Whole Cigarette Smoke

1985 ◽  
Vol 13 (2) ◽  
pp. 67-73 ◽  
Author(s):  
CDR Borland ◽  
AT Chamberlain ◽  
TW Higenbottam ◽  
RW Barber ◽  
BA Thrush
Keyword(s):  
Nitric Oxide ◽  
Gas Phase ◽  
Cigarette Smoke ◽  
Single Port ◽  
First Order ◽  
First Order Kinetics ◽  
Rate Of Reaction ◽  
Pseudo Second Order ◽  
Oxidation Of No ◽  
Whole Smoke

AbstractThere remains uncertainty about the rate of oxidation of nitric oxide (NO) in cigarette smoke. Using a single-port smoking machine and a chemiluminescence NO analyser we have investigated the rate of NO disappearance during cigarette smoke ageing over 10 minutes for gas phase and whole smoke. The disappearance of NO in whole smoke conformed to the (pseudo) second order kinetics observed for oxidation of NO in air. In the gas phase however the rate of disappearance was more rapid and appeared to follow first order kinetics. The possible mechanisms for this difference in behaviour are discussed.

scholarly journals Rapid compressions in a captive bubble apparatus are isothermal

2003 ◽  
Vol 95 (5) ◽  
pp. 1896-1900
Author(s):  
Wenfei Yan ◽  
Stephen B. Hall
Keyword(s):  
Hydrostatic Pressure ◽  
Gas Phase ◽  
Pulmonary Surfactant ◽  
First Order ◽  
First Order Kinetics ◽  
Gas Phase Molecules ◽  
Actual Change ◽  
Phase Temperature ◽  
Two Phases ◽  
Interfacial Films

Captive bubbles are commonly used to determine how interfacial films of pulmonary surfactant respond to changes in surface area, achieved by varying hydrostatic pressure. Although assumed to be isothermal, the gas phase temperature (Tg) would increase by >100°C during compression from 1 to 3 atm if the process were adiabatic. To determine the actual change in temperature, we monitored pressure (P) and volume (V) during compressions lasting <1 s for bubbles with and without interfacial films and used P · V to evaluate Tg. P · V fell during and after the rapid compressions, consistent with reductions in n, the moles of gas phase molecules, because of increasing solubility in the subphase at higher P. As expected for a process with first-order kinetics, during 1 h after the rapid compression P · V decreased along a simple exponential curve. The temporal variation of n moles of gas was determined from P · V >10 min after the compression when the two phases should be isothermal. Back extrapolation of n then allowed calculation of Tg from P · V immediately after the compression. Our results indicate that for bubbles with or without interfacial films compressed to >3 atm within 1 s, the change in Tg is <2°C.

scholarly journals The Determination of Nitric Oxide in Gas Phase Cigarette Smoke by Non-dispersive Infrared Analysis

1980 ◽  
Vol 10 (2) ◽  
Author(s):  
T. B. Williams
Keyword(s):  
Nitric Oxide ◽  
Gas Phase ◽  
Cigarette Smoke ◽  
Relative Error ◽  
Dead Volume ◽  
High Yield ◽  
Infrared Analysis ◽  
Colorimetric Analysis ◽  
Standard Gas

AbstractNitric oxide in cigarette smoke was conveniently determined by non-dispersive infrared analysis (NDIR). Recoveries of 95 % were obtained with standard gas-air mixtures but recoveries from smoke increased from 87% for high-yield to 91 % for low-yield cigarettes. Relative error was about 4 %. A reduction in the dead volume of Cambridge filter cassettes, to reduce the amount of NO reacted between puffs, increased NO deliveries of cigarettes by 4%. Deliveries of NO were estimated to average 4 % lower due to oxidation, but reaction with other smoke components reduced them further depending upon concentrations. The NO deliveries of cigarettes increased as blend nitrate increased and as the flow of air around cigarettes decreased. Nitric oxide in smoke and in standard gas-air mixtures, determined by non-dispersive infrared (NDIR) spectroscopy, was substantiated by an automated colorimetric analysis. Interfering smoke species were determined and circumvented in both methods.

Kinetics of NO2 air space absorption in isolated rat lungs

1992 ◽  
Vol 73 (5) ◽  
pp. 1939-1945 ◽  
Author(s):  
E. M. Postlethwait ◽  
S. D. Langford ◽  
A. Bidani
Keyword(s):  
Steady State ◽  
Tidal Volume ◽  
Gas Phase ◽  
Initial Rate ◽  
Quasi Steady State ◽  
Closed Chamber ◽  
First Order ◽  
First Order Kinetics ◽  
Rat Lungs ◽  
Kinetics Of

We previously showed, during quasi-steady-state exposures, that the rate of inhaled NO2 uptake displays reaction-mediated characteristics (J. Appl. Physiol. 68: 594–603, 1990). In vitro kinetic studies of pulmonary epithelial lining fluid (ELF) demonstrated that NO2 interfacial transfer into ELF exhibits first-order kinetics with respect to NO2, attains [NO2]-dependent rate saturation, and is aqueous substrate dependent (J. Appl. Physiol. 71: 1502–1510, 1991). We have extended these observations by evaluating the kinetics of NO2 gas phase disappearance in isolated ventilating rat lungs. Transient exposures (2–3/lung at 25 degrees C) employed rebreathing (NO2-air) from a non-compliant continuously stirred closed chamber. We observed that 1) NO2 uptake rate is independent of exposure period, 2) NO2 gas phase disappearance exhibited first-order kinetics [initial rate (r*) saturation occurred when [NO2] > 11 ppm], 3) the mean effective rate constant (k*) for NO2 gas phase disappearance ([NO2] < or = 11 ppm, tidal volume = 2.3 ml, functional residual capacity = 4 ml, ventilation frequency = 50/min) was 83 +/- 5 ml/min, 4) with [NO2] < or = 11 ppm, k* and r* were proportional to tidal volume, and 5) NO2 fractional uptakes were constant across [NO2] (< or = 11 ppm) and tidal volumes but exceeded quasi-steady-state observations. Preliminary data indicate that this divergence may be related to the inspired PCO2. These results suggest that NO2 reactive uptake within rebreathing isolated lungs follows first-order kinetics and displays initial rate saturation, similar to isolated ELF.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Nanosized centers for mercury(II) ions adsorption on a surface of modified silica

2008 ◽  
Vol 6 (4) ◽  
pp. 581-591 ◽  
Author(s):  
Lyudmila Belyakova ◽  
Oleksandra Shvets ◽  
Diana Lyashenko
Keyword(s):  
Aqueous Medium ◽  
Batch Adsorption ◽  
Modified Silica ◽  
First Order ◽  
Chemically Modified ◽  
First Order Kinetics ◽  
Adsorption Data ◽  
Pseudo Second Order ◽  
Kinetics Of ◽  
Second Order Equations

AbstractThe present work investigates the adsorptive interactions of Hg(II) ions in aqueous medium with hydroxylated silica, aminopropylsilica and silica chemically modified by β-cyclodextrin. Batch adsorption studies were carried out with various agitation times and mercury(II) concentrations. The maximum adsorption was observed within 15–30 min of agitation. The kinetics of the interactions, tested with the model of Lagergren for pseudo-first and pseudo-second order equations, showed better agreement with first order kinetics (k1 = 3.4 ± 0.2 to 5.9 ± 0.3 min−1). The adsorption data gave good fits with Langmuir isotherms. The results have shown that β-cyclodextrin-containing adsorbent has the largest adsorption specificity to Hg(II): K L = 4125 ± 205 mmol−1. “β-cyclodextrin-NO3-” inclusion complexes with ratio 1: 1 and super molecules with composition C42H70O35 ⊎ 3 Hg(NO3)2 are formed on the surface of β-cyclodextrin-containing silica.

scholarly journals A Trapping System for the Combined Determination of Total HCN and Total Gas Phase Aldehydes in Cigarette Smoke

1973 ◽  
Vol 7 (2) ◽  
Author(s):  
P.F. Collins ◽  
N.M. Sarji ◽  
J.F. Williams
Keyword(s):  
Standard Deviation ◽  
Gas Phase ◽  
Cigarette Smoke ◽  
Silica Gel ◽  
Single Port ◽  
Particulate Phase ◽  
Combined Procedure ◽  
Relative Standard ◽  
Small Tube

AbstractA procedure for the combined determination of total HCN and total gas phase aldehydes in cigarette smoke has been developed which is practical to use for the analysis of relatively large cigarette samples. The smoking system includes a Cambridge pad for collection of the particulate phase and a small tube of silica gel to trap gas phase components, with 5 cigarettes being smoked through each pad and trap. Following smoking, the Cambridge pad and silica gel trap are extracted; the silica gel extract is used for the determination of total gas phase aldehydes and the combined extracts for HCN analysis. Colourimetric procedures, automated through use of the Technicon AutoAnalyser as described previously, are employed for the analysis of the sample extracts. Evaluation of this combined procedure indicates that it yields reliable results for both total HCN and total gas phase aldehydes with greater speed and ease of operation than provided by the previously described methods. The procedure has been applied to various cigarette samples with the relative standard deviation for a single port of 5 cigarettes ranging from 1.9 to 5.5 % for gas phase aldehydes and from 2.6 to 8.4 % for total HCN.

scholarly journals Use of semi-conducting bismuth sulfide as a photocatalyst for degradation of rose bengal

2011 ◽  
Vol 30 (2) ◽  
pp. 229 ◽  
Author(s):  
Shweta Sharma ◽  
Rakshit Ameta ◽  
R. K. Malkani ◽  
Suresh C. Ameta
Keyword(s):  
Light Intensity ◽  
Rose Bengal ◽  
Bismuth Sulfide ◽  
Optimum Conditions ◽  
First Order ◽  
First Order Kinetics ◽  
Degradation Of Dyes ◽  
Textile Dyeing ◽  
Rate Of Reaction ◽  
Pseudo First Order

Different methods have been adopted for the removal and degradation of dyes from effluents of textile, dyeing and printing industries. These methods have their own merits and drawbacks. In the present investigation, bismuth sulfide has been used as a photocatalyst for the degradation of rose Bengal. The effect of different parameters like the pH, concentration of dye solution, amount of semiconductor and light intensity on the rate of reaction has been investigated. The reaction follows pseudo-first order kinetics. The optimum conditions were obtained as: [rose Bengal] = 1.60·10–5 M; Bi2S3 = 0.10 g; pH = 8.5, and light intensity = 50.0 mW·cm–2. The rate constant was 4.68·10–5 sec–1. A mechanism has been proposed for the degradation of rose Bengal involving hydroxyl radicals.

IR laser driven decomposition of oxalyl chloride in presence or radical scavengers: Evidence for molecular mechanism

1982 ◽  
Vol 47 (12) ◽  
pp. 3258-3260 ◽  
Author(s):  
Josef Pola
Keyword(s):  
Nitric Oxide ◽  
Molecular Mechanism ◽  
Oxalyl Chloride ◽  
Radical Scavengers ◽  
First Order ◽  
First Order Kinetics ◽  
Ir Laser

CO2 laser-induced and SF6 (0.4-0.5 kPa) sensitized decomposition of oxalyl chloride (4 kPa) in the presence of radical scavengers (2.6-8.7 kPa) as hydrogen, propene and nitric oxide obeys first-order kinetics and is supportive of the view that oxalyl chloride thermally decomposes by concerted molecular mechanism.

The Spectrophotometric Determination of Formaldehyde in Whole Smoke/Eine spektralphotometrische Methode zur Bestimmung von Formaldehyd im Vollrauch von Cigaretten

1971 ◽  
Vol 6 (1) ◽  
Author(s):  
H.P. Stauffer ◽  
J. Bourquin
Keyword(s):  
Gas Phase ◽  
Cigarette Smoke ◽  
Carbonyl Compounds ◽  
Ammonium Ion ◽  
Buffer Solution ◽  
Simple Method ◽  
Different Types ◽  
Volatile Aldehydes ◽  
Whole Smoke

AbstractThe quantitative determination of formaldehyde in the gas phase of cigarette smoke does not permit any conclusion about the actual level in whole smoke. This is due to the fact that a Cambridge filter charged with smoke condensate absorbs up to 50 % of the volatile aldehydes from the gas phase. A simple method is presented making possible the estimation of formaldehyde in whole cigarette smoke. The procedure is based on the Hantzsch reaction between formaldehyde, acetylacetone and ammonium ion in an aqueous buffer solution. The reaction product, 3,5-diacetyl1,4-dihydrolutidine, has an absorption maximum at 412 nm and is measured spectrophotometrically. The operations are simple and there are no separation steps required. Reproducibility is excellent and interference by other carbonyl compounds can be neglected. Acetaldehyde in concentrations 10 times higher than formaldehyde interferes to less than 1 %. Different types of cigarettes have been analysed with respect to their delivery of formaldehyde. Values found range from 40 to 90 µg per cigarette. The concentrations found in whole smoke are significantly higher than the values cited in the Iiterature for gas phase formaldehyde

Di-tert-butyl peroxide decomposition behind shock waves

1976 ◽  
Vol 54 (4) ◽  
pp. 581-585 ◽  
Author(s):  
David K. Lewis
Keyword(s):  
Thermal Decomposition ◽  
Gas Phase ◽  
Single Pulse ◽  
First Order ◽  
Tert Butyl ◽  
First Order Kinetics ◽  
Peroxide Decomposition ◽  
Butyl Peroxide ◽  
Temperature Work ◽  
Lower Temperature

The homogeneous, gas phase thermal decomposition of di-tert-butyl peroxide has been studied in a single pulse shock tube. Samples containing 0.05% to 0.5% reactant in argon were heated to 528–677 K at total pressures of about 1 atm. Acetone and ethane were the only significant products. The reaction obeyed first order kinetics. The Arrhenius parameters, log A (s−1) = 15.33 ± 0.50, Eact (kJ/mol) = 152.3 ± 5.8, are in agreement with the bulk of the earlier reported results of lower temperature work, and with a recently reported result obtained via the very low pressure pyrolysis technique. Indications from some of the earlier work that the A factor may decline at high temperatures are not supported by the present study.

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