Gaseous Acetic Acid Research Articles

Functional geraniol-Ca(OH)2 composite/sodium acetate alginate film on nonwoven polyethylene sheet: acetic acid gas production in response to acid

An alginate film, which released geraniol under ordinary conditions and produced acetic acid gas in response to acid, was directly prepared on a polyethylene nonwoven sheet. This alginate film was composed of geraniol-calcium hydroxide [Ca(OH)2] composite, which was prepared by mixing geraniol and calcium oxide (CaO), and sodium alginate solution (Na-Alg) containing sodium acetic acid (CH3COONa). Geraniol release from the alginate film could be monitored over time. Optimal conditions for the alginate film preparation were 0.75 or 1.0% Na-Alg solution containing 10% (w/v) CH3COONa. Acetic acid (~3.58 ppm) could be generated from the sheet under these conditions by dropping 1.0 M hydrochloric acid (0.3 mL) onto it. We successfully prepared a functional sheet, which changed its released odor from geraniol to acetic acid gas in response to acid.

Gas phase acetic acid and its qualitative effects on snow crystal morphology and the quasi-liquid layer

Abstract. A chamber was constructed within which snow crystals were grown on a string at various temperatures, relative humidities, and acetic acid gas phase mole fractions. The temperature, relative humidity, and acid mole fraction were measured for the first time at the point of crystal growth. Snow crystal morphological transition temperature shifts were recorded as a function of acid mole fraction, and interpreted according to the calculated acid concentration in the crystal's quasi-liquid layer, which is believed to have increased in thickness as a function of acid mole fraction, thereby affecting the crystal's morphology consistent with the hypothesis of Kuroda and Lacmann. Deficiencies in the understanding of the quasi-liquid layer and its role in determining snow crystal morphology are briefly discussed.

Inkjet printed LED based pH chemical sensor for gas sensing

Predictable behaviour is a critical factor when developing a sensor for potential deployment within a wireless sensor network (WSN). The work presented here details the fabrication and performance of an optical chemical sensor for gaseous acetic acid analysis, which was constructed using inkjet printed deposition of a colorimetric chemical sensor. The chemical sensor comprised a pH indicator dye (bromophenol blue), phase transfer salt tetrahexylammonium bromide and polymer ethyl cellulose dissolved in 1-butanol. A paired emitter-detector diode (PEDD) optical detector was employed to monitor responses of the colorimetric chemical sensor as it exhibits good sensitivity, low power consumption, is low cost, accurate and has excellent signal-to-noise ratios. The chemical sensor formulation was printed directly onto the surface of the emitter LED, and the resulting chemical sensors characterised with respect to their layer thickness, response time and recovery time. The fabrication reproducibility of inkjet printed chemical sensors in comparison to drop casted chemical sensors was investigated. Colorimetric chemical sensors produced by inkjet printing, exhibited an improved reproducibility for the detection of gaseous acetic acid with a relative standard deviation of 5.5% in comparison to 68.0% calculated for drop casted sensors ( n = 10). The stability of the chemical sensor was also investigated through both intra and inter-day studies.

Facile Synthesis and Characterization of Iron Oxide Semiconductor Nanowires for Gas Sensing Application

We report a facile and efficient synthesis technique for the preparation of iron oxide semiconductor nanowires in large quantity by using nitrilotriacetic acid (NTA) as a chelating agent to form polymeric chains, followed by heat treatment. This technique can also be applied for preparing other transition metal oxide nanowires such as MnO2 nanowires and NiO nanowires. The as-prepared α-Fe2O3 nanowires have exhibited a blue shift of bandgap, peculiar magnetic properties, and high sensitivities toward ethanol and acetic acid gases.

Atmospheric corrosion of historical organ pipes: The influence of environment and materials

The corrosion of lead-rich pipes in historical organs in different parts of Europe has been investigated. The influence of the environment and the composition and microstructure of the pipe metal was studied. Pipe corrosion was documented by visual inspection (boroscope). The corrosion attack and the composition and microstructure of the metal were characterized by OM, SEM, XRD, IC and FAAS. It is shown that the degree of corrosion of the pipes is correlated to the concentration of gaseous acetic and formic acid in the organ. The organic acids are emitted by the wood from which the wind system is built. It is also shown that pipe corrosion decreases with increasing tin content in the range 0–4% (wt). Possible conservation strategies are discussed.

Electronic excitation of gaseous acetic acid studied by K-shell electron energy loss spectroscopy and ab initio calculations

Ab initio Configuration Interaction calculations have been carried out in order to assign the bands observed in the carbon and oxygen K-shell spectra of gaseous acetic acid, measured using the inner-shell electron energy loss spectroscopy (ISEELS) method with better energy resolution than in previous studies. The good agreement between the theoretical and the measured spectra allows us to assign precisely most of the peaks, especially for the Rydberg states. Some of them have been shown to have strong valence character. The lowest energy band at the carbon edge is assigned to the transitions 1sC1→3pπ/σ*(C1–H) and 1sC1→π*(C2–O2). Simple Franck–Condon calculations, based on the linear coupling approximation, were performed in order to reproduce the vibrational structure observed for the first time in the oxygen and carbon core excited species as well as in the previously measured X-ray photoelectron spectroscopy spectra of the core ionised molecule. Finally, the calculated structural parameters of the core states of acetic acid match well those of the corresponding valence states of their Z+1 molecules, as predicted by the equivalent core approximation. However, significant differences between the geometry of the 1sC1→π*(C2–O2) state and the CH3NOOH ground state are obtained.

Atmospheric water-soluble organic carbon measurements at Summit, Greenland

The recently discovered active photochemistry in the surface layers of polar snow may complicate the interpretation of organic compounds found in ice cores. In order to better understand the transformation and cycling of organic species in Arctic surface snow, measurements of water-soluble organic carbon (WSOC) in the gas (WSOC G) and particle (WSOC P) phases were made during the 2006 summer season at Summit, Greenland. These samples represent the first direct, simultaneous measurements of both WSOC G and WSOC P at Summit. From early June to early July, WSOC G and WSOC P concentrations at 150 cm above the snow averaged 667 and 194 ng C m −3, respectively. This value for WSOC G is very similar in magnitude to the sum of acetic and formic acid gas concentrations measured during previous summers at Summit, suggesting that these two monocarboxylic acids constitute a significant fraction of the mass of measured WSOC G. Firn air measurements of WSOC G revealed concentrations within the snowpack nearly an order of magnitude greater than those in the air just above the snow. During one period, four out of five consecutive nights showed concurrent decreases in WSOC G and increases in WSOC P, likely resulting from temperature-dependent gas-to-particle partitioning, as these episodes occurred during the coldest part of the early morning.

Determination of Acetic Acid in Fermentation Broth by Gas‐Diffusion Technique

AbstractDue to the interfering effects of acetic acid in many fermentation processes, a gas‐diffusion technique was developed for the online determination of acetic acid. The measurements were accomplished with a flow diffusion analysis (FDA) unit from the TRACE Analytics GmbH, Braunschweig, Germany. The diffusion analysis is based on the UV‐absorbance of acetic acid at 205 nm. The measurement was achieved by the separation of an acceptor and a carrier stream (acidified fermentation broth) using a gas permeable polytetrafluoroethylene (PTFE) membrane, whereby broth constituents that would otherwise disturb the UV‐measurement of acetic acid, are held back efficiently. Merely, the fermentation by‐products, e.g. formic acid, is capable of diffusing through the membrane. While formic acid can disturb the measurement, carbon dioxide does not absorb at 205 nm. The method operates with time‐dependent sample enrichment. During the analysis, a small volume of the acceptor stream is stopped for a defined time interval in the acceptor chamber. During this period, the gaseous acetic acid diffuses through the membrane and is enriched in the acceptor chamber. Subsequently after the enrichment, the acceptor stream flows through a UV‐detector. The intensity of the signal is proportional to the acetic acid concentration. Online measurements in bioreactors via a sterile filtration probe have been accomplished. A linear calibration in the range of 0.5–5.0 g/L acetic acid with a relative standard deviation of <5 % was obtained. A sampling rate of 8 samples per hour was possible. The system was applied for the determination of acetic acid in E. coli fermentation broth. The instrument is easy to clean, very user‐friendly and does not require any toxic or expensive reagents.

Low level of galacto-oligosaccharide in infant formula stimulates growth of intestinal Bifidobacteria and Lactobacilli

To investigate the effect of a new infant formula supplemented with a low level (0.24 g/100 mL) of galacto-oligosaccharide (GOS) on intestinal micro-flora (Bifidobacteria, Lactobacilli and E. coli) and fermentation characteristics in term infants, compared with human milk and a standard infant formula without GOS. Term infants (n = 371) were approached in this study in three hospitals of China. All infants started breast-feeding. Those who changed to formula-feeding within 4 wk after birth were randomly assigned to one of the two formula groups. Growth and stool characteristics, and side effects that occurred in recruited infants were recorded in a 3-mo follow-up period. Fecal samples were collected from a subpopulation of recruited infants for analysis of intestinal bacteria (culture technique), acetic acid (gas chromatography) and pH (indicator strip). After 3 mo, the intestinal Bifidobacteria, Lactobacilli, acetic acid and stool frequency were significantly increased, and fecal pH was decreased in infants fed with the GOS-formula or human milk, compared with those fed with the formula without GOS. No significant differences were observed between the GOS formula and human milk groups. Supplementation with GOS did not influence the incidence of crying, regurgitation and vomiting. A low level of GOS (0.24 g/100 mL) in infant formula can improve stool frequency, decrease fecal pH, and stimulate intestinal Bifidobacteria and Lactobacilli as in those fed with human milk.

Atmospheric Corrosion of Zinc by Organic Constituents : I. The Role of the Zinc/Water and Water/Air Interfaces Studied by Infrared Reflection/Absorption Spectroscopy and Vibrational Sum Frequency Spectroscopy

The zinc oxide/water and water/air interfaces have been investigated in order to elucidate the role of these two interfaces in an atmospheric corrosion process. Vibrational sum frequency spectroscopy (VSFS) has been used to study the water/air interface of aqueous acetic acid and acetaldehyde solutions. The VSFS studies revealed that the interfacial region of the acetic acid solutions is dominated by various species formed by hydrogen bonding, whereas acetaldehyde underwent a hydration process to form a gem-diol. In both cases, even small additions resulted in a breakdown of the surface structure found in pure water. Infrared reflection/absorption spectroscopy (IRAS) has been utilized to examine the zinc oxide/water interface upon exposure of gaseous acetic acid and acetaldehyde at various relative humidities. The in situ IRAS investigations indicated a formation of zinc acetate both when the zinc oxide surface was exposed to acetic acid and acetaldehyde. Thus, despite being different in nature, these compounds resulted in the same end product in the corrosion process studied.

VUV photophysics of acetic acid: Fragmentation, fluorescence and ionization in the 6–23 eV region

VUV photodissociation of gaseous acetic acid was studied in the 6–23 eV range using synchrotron radiation excitation, photofragment fluorescence spectroscopy and mass spectrometry. OH (A-X), CH (A,B-X) and H-Balmer emissions were observed. Their relative intensities were studied by fluorescence excitation spectroscopy. The fluorescence quantum yield for OH emission has a maximum of 0.9% at 13.3 eV photoexcitation, dropping to 0.5% at 20 eV; that for CH (A-X) is 0.35% at 16 eV and 0.4% at 20 eV. Photoionization mass spectra (PIMS) of CH 3COOH were measured and the appearance energies of the principal photoions were determined. IE(CH 3COOH) = 10.58 ± 0.02 eV is 40–60 meV lower than previous PIMS values. Dissociative ionization reaction channels are discussed in detail. The results call into question previous determinations of the heat of formation and ionization energy of the acetyl radical. A new pathway is suggested for the formation of HCO +, and the assignments of the m/ z = 16, 28 and 31 ions are clarified. The formation of CH 3 + at threshold is shown to involve carbon–carbon bond rupture and a potential energy barrier. The results of this study are used to discuss aspects of astrophysical observations involving the parent and fragment species.

Theoretical interpretation of the infrared lineshape of liquid and gaseous acetic acid

We have applied a model used recently [P. Blaise, M.J. Wojcik, O. Henri-Rousseau, J. Chem. Phys. 122 (2005) 64306] to unpolarized ν X–H infrared lineshapes of cyclic (CH 3COOH) 2 in liquid and gaseous phases and (CD 3COOH) 2 in gaseous phase and taking into account the IR A g forbidden transition. This model incorporates (i) the anharmonic coupling between the high frequency mode and the H-bond bridge, (ii) the Davydov coupling between the excited states of the two moieties, (iii) the quantum direct and indirect dampings. The approach reproduces satisfactorily the main features of the experimental lineshapes by using a minimum number of independant parameters.

Development and integration of new processes consuming carbon dioxide in multi-plant chemical production complexes

Fourteen new energy-efficient and environmentally acceptable catalytic processes have been identified that can use excess high-purity carbon dioxide as a raw material available in a chemical production complex. The complex in the lower Mississippi River Corridor was used to show how these new plants could be integrated into this existing infrastructure using the chemical complex analysis system. Eighty-six published articles of laboratory and pilot plant experiments were reviewed that describe new methods and catalysts to use carbon dioxide for producing commercially important products. A methodology for selecting the new energy-efficient processes was developed based on process operating conditions, energy requirements, catalysts, product demand and revenue, market penetration and economic, environmental and sustainable costs. Based on the methodology for selecting new processes, 20 were identified as candidates for new energy efficient and environmentally acceptable plants. These processes were simulated using HYSYS, and a value-added economic analysis was evaluated for each process. From these, 14 of the most promising were integrated in a superstructure that included plants in the existing chemical production complex in the lower Mississippi River corridor (base case). The optimum configuration of plants was determined based on the triple bottom line that includes sales, economic, environmental and sustainable costs using the chemical complex analysis system. From 18 new processes in the superstructure, the optimum structure had seven new processes including acetic acid, graphite, formic acid, methylamines, propylene and synthesis gas production. With the additional plants in the optimal structure the triple bottom line increased from $343 million per year to $506 million per year and energy use increased from 2,150 TJ/year to 5,791 TJ/year. Multicriteria optimization has been used with Monte Carlo simulation to determine the sensitivity of prices, costs, and sustainability credits/cost to the optimal structure of a chemical production complex. In essence, for each Pareto optimal solution, there is a cumulative probability distribution function that is the probability as a function of the triple bottom line. This information provides a quantitative assessment of the optimum profit versus sustainable credits/cost, and the risk (probability) that the triple bottom line will meet expectations. The capabilities of the chemical complex analysis system have been demonstrated, and this methodology could be applied to other chemical complexes in the world for reduced emissions and energy savings. The system was developed by industry–university collaboration, and the program with users manual and tutorial can be downloaded at no cost from the LSU Mineral Processing Research Institute’s website http://www.mpri.lsu.edu.

Theoretical interpretation of the line shape of the gaseous acetic acid cyclic dimer

A general quantum theoretical approach of the nu(X-H) IR line shape of cyclic dimers of weakly H-bonded species in the gas phase is proposed. In this model, the adiabatic approximation (allowing to separate the high frequency motion from the slow one of the H-bond bridge), is performed for each separate H-bond bridge of the dimer and a strong nonadiabatic correction is introduced into the model via the resonant exchange between the fast mode excited states of the two moieties. The present model reduces satisfactorily to many models in the literature dealing with more special situations. It has been applied to the cyclic dimers (CD(3)CO(2)H)(2) and (CD(3)CO(2)D)(2) in the gas phase. It correctly fits the experimental line shape of the hydrogenated compound and predict satisfactorily the evolution in the line shapes, to the deuterated one by reducing simply the angular frequency of the H-bond bridge and the anharmonic coupling parameter by the factor 1/ square root of 2.

Evolution of gases and particles from a savanna fire in South Africa

Airborne measurements of particles and gases from a 1000‐ha savanna fire in South Africa are presented. These measurements represent the most extensive data set reported on the aging of biomass smoke. The measurements include total concentrations of particles (CN), particle sizes, particulate organic carbon and black carbon, light‐scattering coefficients, downwelling UV fluxes, and mixing ratios for 42 trace gases and 7 particulate species. The ratios of excess nitrate, ozone, and gaseous acetic acid to excess CO increased significantly as the smoke aged over ∼40–45 min, indicating that these species were formed by photochemistry in the plume. For 17 other species, the excess mixing ratio normalized by the excess mixing ratio of CO decreased significantly with smoke age. The relative rates of decrease for a number of chemical species imply that the average OH concentration in the plume was ∼1.7 × 107 molecules cm−3. Excess CN, normalized by excess CO, decreased rapidly during the first ∼5 min of aging, probably due to coagulation, and then increased, probably due to gas‐to‐particle conversion. The CO‐normalized concentrations of particles <1.5 μm in diameter decreased, and particles >1.5 μm diameter increased, with smoke age. The spectral depletion of solar radiation by the smoke is depicted. The downwelling UV flux near the vertical center of the plume was about two‐thirds of that near the top of the plume.

Evaluation of Volatile Chemical Treatments for Lethality to Salmonella on Alfalfa Seeds and Sprouts

A study was done to evaluate natural volatile compounds for their ability to kill Salmonella on alfalfa seeds and sprouts. Acetic acid, allyl isothiocyanate (AIT), trans-anethole, carvacrol, cinnamic aldehyde, eugenol, linalool, methyl jasmonate, and thymol were examined for inhibitory and lethal activity against Salmonella by exposing inoculated alfalfa seeds to compounds (1,000 mg/liter of air) for 1, 3, and 7 h at 60°C. Only acetic acid, cinnamic aldehyde, and thymol caused significant reductions in Salmonella populations (>3 log10 CFU/g) compared with the control (1.9 log10 CFU/g) after treatment for 7 h. Treatment of seeds at 50°C for 12 h with acetic acid (100 and 300 mg/liter of air) and thymol or cinnamic aldehyde (600 mg/liter of air) significantly reduced Salmonella populations on seeds (>1.7 log10 CFU/g) without affecting germination percentage. Treatment of seeds at 50°C with AIT (100 and 300 mg/liter of air) and cinnamic aldehyde or thymol (200 mg/liter of air) did not significantly reduce populations compared with the control. Seed germination percentage was largely unaffected by treatment with gaseous acetic acid, AIT, cinnamic aldehyde, or thymol for up to 12 h at 50°C. The number of Salmonella on seeds treated at 70°C for 80 min with acetic acid (100 and 300 mg/liter of air), AIT (100 mg/liter of air), and cinnamic aldehyde and thymol (600 mg/liter of air) at water activity (aw) 0.66 was not significantly different than the number inactivated on seeds at aw 0.49. Acetic acid at 200 and 500 mg/liter of air reduced an initial population of 7.50 log10 CFU/g of alfalfa sprouts by 2.33 and 5.72 log10 CFU/g, respectively, within 4 days at 10°C, whereas AIT at 200 and 500 mg/liter of air reduced populations to undetectable levels; however, both treatments caused deterioration in sensory quality. Treatment of sprouts with 1 or 2 mg of AIT per liter of air adversely affected sensory quality but did not reduce Salmonella populations after 11 days of exposure at 10°C.

Improvement of Japanese Wheat Flour by Gaseous Acetic Acid Treatment.

Ten different Japanese wheat flours with protein contents ranging between 9.86 and 11.5% were treated with gaseous acetic acid, then used for breadmaking. Gaseous acetic acid treatment at a concentration of 0.5–1.5 ml acetic acid per kg of the flour improved breadmaking properties of bread height and specific volume. It is known that the level of these breadmaking properties is related to the protein content of the wheat flour. The slight acetic acid flavor in the breadcrumbs was masked by adding butter flavor or butter to the bread dough.

Emissions of formaldehyde, acetic acid, methanol, and other trace gases from biomass fires in North Carolina measured by airborne Fourier transform infrared spectroscopy

Biomass burning is an important source of many trace gases in the global troposphere. We have constructed an airborne trace gas measurement system consisting of a Fourier transform infrared spectrometer (FTIR) coupled to a “flow‐through” multipass cell (AFTIR) and installed it on a U.S. Department of Agriculture Forest Service King Air B‐90. The first measurements with the new system were conducted in North Carolina during April 1997 on large, isolated biomass fire plumes. Simultaneous measurements included Global Positioning System (GPS); airborne sonde; particle light scattering, CO, and CO2; and integrated filter and canister samples. AFTIR spectra acquired within a few kilometers of the fires yielded excess mixing ratios for 10 of the most common trace gases in the smoke: water, carbon dioxide, carbon monoxide, methane, formaldehyde, acetic acid, formic acid, methanol, ethylene, and ammonia. Emission ratios to carbon monoxide for formaldehyde, acetic acid, and methanol were each 2.5±1%. This is in excellent agreement with (and confirms the relevance of) our results from laboratory fires. However, these ratios are significantly higher than the emission ratios reported for these compounds in some previous studies of “fresh” smoke. We present a simple photochemical model calculation that suggests that oxygenated organic compounds should be included in the assessment of ozone formation in smoke plumes. Our measured emission factors indicate that biomass fires could account for a significant portion of the oxygenated organic compounds and HOxpresent in the tropical troposphere during the dry season. Our fire measurements, along with recent measurements of oxygenated biogenic emissions and oxygenated organic compounds in the free troposphere, indicate that these rarely measured compounds play a major, but poorly understood, role in the HOx, NOx, and O3chemistry of the troposphere.

Effect of Gaseous Acetic Acid Treatment on Breadmaking Properties of Flour

ABSTRACTEleven different wheat flours of varying protein content were treated with gaseous acetic acid. Each wheat flour exhibited maximum breadmaking properties (bread height and specific volume) at different levels of gaseous acetic acid treatment. There was a relationship (r = +0.7384) between the level of gaseous acetic acid treatment required for maximum breadmaking properties and the protein content of the wheat flour. Wheat flours with higher protein contents were more resistant to the decrease in pH value due to acetic acid treatment.

Disinfection of Mung Bean Seed with Gaseous Acetic Acid

Mung bean seed inoculated with Salmonella Typhimurium, Escherichia coli O157:H7, and Listeria monocytogenes (3 to 5 log CFU/g) was exposed to gaseous acetic acid in an aluminum fumigation chamber. Salmonella Typhimurium and E. coli O157:H7 were not detected by enrichment of seeds treated with 242μl of acetic acid per liter of air for 12 h at 45°C. L. monocytogenes was recovered by enrichment from two of 10 25-g seed samples treated in this manner. Fumigation with gaseous acetic acid was also lethal to indigenous bacteria and fungi on mung bean seed. The treatment did not significantly reduce seed germination rates, and no differences in surface microstructure were observed between treated and untreated seed viewed by scanning electron microscopy.