Abstract  An effective ketonization of 1-butanol mixed with water vapor over the catalyst Pr1.467Bi0.533Sr2O5.928 Of monoclinically distorted perovskite structure is reported. The catalyst is characteristic of 1.2 at.% of oxygen vacancies, supposed to act as active centers of Lewis type, and of a high oxidative ability reflected by large change in the catalyst's effective valence factor (V-3). The ketonization performed without water addition is accompanied with total carbonization of 1-butanol, caused by the catalyst's oxygen, the latter easily releasable beginning from low temperatures. This negative effect is practically removable if the process is performed under the presence of water vapor. It is also found that water addition influences the formation Of C3H7-CH=O aldehyde and Of C3H7-CO-C3H7 ketone. Nevertheless, water addition leads to a steady destruction of the catalyst's crystal structure because Of CO2, appearing in course of the WGSR process, and of its subsequent reaction with the structure component SrO to SrCO3. The catalyst is found easily reproducible by its re-oxidation in air at 850-900 degrees C. (C) 2009 Elsevier B.V. All rights reserved.

Abstract  Polarized solid targets have been used in nuclear and particle physics experiments since the early 1960s, and with the development of superconducting magnets and He-3/He-4 dilution refrigerators in the early 1970s, proton polarization values of 80-100% have been achieved routinely in various target materials at two standard magnetic field and temperature conditions (2.5 T, <0.3 K and 5 T, 1 K). Due to the much lower magnetic moment of the deuteron compared with that of the proton, deuteron polarization values have been considerably lower, typically 30-40% in chemically doped alcohols (d-butanol), 40-45% in radiation-doped ammonia (ND3), and 50-55% in irradiated lithium-deuteride. Now, however, research at the University of Bochum - including systematical electron spin resonance (ESR) investigations in order to study the properties of the paramagnetic dopants (i.e., their ESR line width) - is yielding alcohol and diol materials with deuteron polarizations as high as 80%.

Abstract  The conversion of n-butanol to iso-butene in one-step has been studied over zeolite catalysts (Theta-1, ZSM-2, Ferrierite, ZSM-5, SAPO-11 and Y). The zeolites were characterized by XRF. XRD, BET, and NH(3)-TPD. Coke formation on the spent catalysts was measured by TGA. The unidirectional channel zeolites Theta-1 and ZSM-23 gave high yields of iso-butene and showed high stability. In contrast, ferrierite, although initially active, deactivated due to the presence of water from dehydration giving progressively lower yields of iso-butene. ZSM-5 showed high activity but low selectivity to iso-butene; SAPO-11 was structurally unstable under the reaction conditions. Ferrierite deactivation was studied in more detail by NH(3)-TPD, (27)Al MAS NMR and by a comparison of 1-butene isomerisation with and without the presence of added steam. A similar comparison was made for ZSM-23 and Theta-1 which further emphasised their stability and showed that for these catalysts under the reaction conditions used, the product steam from n-butanol dehydration promoted iso-butene yield by acting as a diluent. (C) 2011 Elsevier B.V. All rights reserved.

Abstract  We study the catalytic condensation of furfuryl alcohol with 1-butanol to butyl levulinate. A screening of several commercial and as-synthesized solid acid catalysts shows that propylsulfonic acid-functionalized mesoporous silica outperforms the state-of-the-art phosphotungstate acid catalysts. The catalyst is prepared via template-assisted sol-gel polycondensation of TEOS and MPTMS. It gives 96 % yield (and 100 % selectivity) of butyl levulinate in 4 h at 110 °C. Reaction profiles before and after a hot filtration test confirm that the active catalytic species do not leach into the solution. The catalyst synthesis, characterization, and mode of operation are presented and discussed.

Abstract  In aqueous acidic media, picolinic acid, 2,2'-bipyridine and 1,10-phenanthroline promoted Cr(VI) oxidation of 1-butanol produces 1-butanal. 1-butanal is separated from mixture by fractional distillation. The anionic surfactant (SDS) and neutral surfactant (TX-100) accelerate the process while the cationic surfactant (CPC) retards the reaction. Combination of bipy and SDS is the best choice for chromic acid oxidation of 1-butanol to 1-butanal in aqueous media.

Abstract  The influence of low-frequency ultrasound (40 kHz) in the esterification reaction between acetic acid and butanol for flavor ester synthesis catalyzed by the commercial immobilized lipase B from Candida antarctica (Novozym 435) was evaluated. A central composite design and the response surface methodology were used to analyze the effects of the reaction parameters (temperature, substrate molar ratio, enzyme content and added water) and their response (yields of conversion in 2.5 h of reaction). The reaction was carried out using n-hexane as solvent. The optimal conditions for ultrasound-assisted butyl acetate synthesis were found to be: temperature of 46 °C; substrate molar ratio of 3.6:1 butanol:acetic acid; enzyme content of 7%; added water of 0.25%, conditions that are slightly different from those found using mechanical mixing. Over 94% of conversion was obtained in 2.5h under these conditions. The optimal acid concentration for the reaction was determined to be 2.0 M, compared to 0.3 M without ultrasound treatment. Enzyme productivity was significantly improved to around 7.5-fold for each batch when comparing ultrasound and standard mechanical agitation. The biocatalyst could be directly reused for 14 reactions cycles keeping around 70% of its original activity, while activity was virtually zeroed in the third cycle using the standard mixing system. Thus, compared to the traditional mechanical agitation, ultrasound technology not only improves the process productivity, but also enhances enzyme recycling and stability in the presence of acetic acid, being a powerful tool to improve biocatalyst performance in this type of reaction.

Abstract  Molecular interactions in 1-butanol + ionic liquid (IL) solutions have been investigated by measuring and modeling activity-coefficient data. The activity coefficients in binary solutions containing 1-butanol and an IL were determined experimentally: the ILs studied were 1-decyl-3-methyl-imidazolium tetracyanoborate ([Im10.1](+)[tcb](-)), 4-decyl-4-methyl-morpholinium tetracyanoborate ([Mo10.1](+)[tcb](-)), 1-decyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide ([Im10.1](+)[ntf2](-)), and 4-decyl-4-methyl-morpholinium bis(trifluoromethylsulfonyl)imide ([Mo10.1](+)[ntf2](-)). The methods used to determine the activity coefficients included vapor-pressure osmometry, headspace-gas chromatography, and gas-liquid chromatography. The results from all of these techniques were combined to obtain activity-coefficient data over the entire IL concentration range, and the ion-specific interactions of the ILs investigated were identified with 1-butanol. The highest (1-butanol)-IL interactions of the ILs considered in this work were found for [Im10.1](+)[tcb](-); thus, [Im10.1](+)[tcb](-) showed the highest affinity for 1-butanol in a binary mixture. The experimental data were modeled with the Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT). PC-SAFT was able to accurately describe the pure IL and (1-butanol)-IL data. Moreover, the model was shown to be predictive and extrapolative with respect to concentration and temperature.

Abstract  A model for the combustion of butanol is studied using a recently developed theoretical method for the systematic improvement of the kinetic mechanism. The butanol mechanism includes 1446 reactions, and we demonstrate that it is straightforward and computationally feasible to implement a full global sensitivity analysis incorporating all the reactions. In addition, we extend our previous analysis of ignition-delay targets to include species targets. The combination of species and ignition targets leads to multitarget global sensitivity analysis, which allows for a more complete mechanism validation procedure than we previously implemented. The inclusion of species sensitivity analysis allows for a direct comparison between reaction pathway analysis and global sensitivity analysis.

Abstract  A polarizable empirical force field based on the classical Drude oscillator has been developed for the aliphatic alcohol series. The model is optimized with emphasis on condensed-phase properties and is validated against a variety of experimental data. Transferability of the developed parameters is emphasized by the use of a single electrostatic model for the hydroxyl group throughout the alcohol series. Aliphatic moiety parameters were transferred from the polarizable alkane parameter set, with only the Lennard-Jones parameters on the carbon in methanol optimized. The developed model yields good agreement with pure solvent properties with the exception of the heats of vaporization of 1-propanol and 1-butanol, which are underestimated by approximately 6%; special LJ parameters for the oxygen in these two molecules that correct for this limitation are presented. Accurate treatment of the free energies of aqueous solvation required the use of atom-type specific O(alcohol)-O(water) LJ interaction terms, with specific terms used for the primary and secondary alcohols. With respect to gas phase properties the polarizable model overestimates experimental dipole moments and quantum mechanical interaction energies with water by approximately 10 and 8 %, respectively, a significant improvement over 44 and 46 % overestimations of the corresponding properties in the CHARMM22 fixed-charge additive model. Comparison of structural properties of the polarizable and additive models for the pure solvents and in aqueous solution shows significant differences indicating atomic details of intermolecular interactions to be sensitive to the applied force field. The polarizable model predicts pure solvent and aqueous phase dipole moment distributions for ethanol centered at 2.4 and 2.7 D, respectively, a significant increase over the gas phase value of 1.8 D, whereas in a solvent of lower polarity, benzene, a value of 1.9 is obtained. The ability of the polarizable model to yield changes in dipole moment as well as the reproduction of a range of condensed phase properties indicates its utility in the study of the properties of alcohols in a variety of condensed phase environments as well as representing an important step in the development of a comprehensive force field for biological molecules.

Abstract  We report highly surface sensitive core-level photoelectron spectra of small carboxylic acids (formic, acetic and butyric acid) and their respective carboxylate conjugate base forms (formate, acetate and butyrate) in aqueous solution. The relative surface propensity of the carboxylic acids and carboxylates is obtained by monitoring their respective C1s signal intensities from a solution in which their bulk concentrations are equal. All the acids are found to be enriched at the surface relative to the corresponding carboxylates. By monitoring the PE signals of acetic acid and acetate as a function of total concentration, we find that the protonation of acetic acid is nearly complete in the interface layer. This is in agreement with literature surface tension data, from which it is inferred that the acids are enriched at the surface while (sodium) formate and acetate, but not butyrate, are depleted. For butyric acid, we conclude that the carboxylate form co-exists with the acid in the interface layer. The free energy cost of replacing an adsorbed butyric acid molecule with a butyrate ion at 1.0 M concentration is estimated to be >5 kJ mol(-1). By comparing concentration dependent surface excess data with the evolution of the corresponding photoemission signals it is furthermore possible to draw conclusions about how the distribution of molecules that contribute to the excess is altered with bulk concentration.

Abstract  The surface tensions of pure ionic liquid, 1-butyl-3-methylimidazolium thiocyanate ([BMIM][SCN]), and binary mixtures of [BMIM][SCN] with alcohols (1-butanol, 1-pentanol, 1-hexanol) have been measured at atmospheric pressure at five temperatures in the range from 298.15 to 328.15 K. These measurements have been provided to complete information of the influence of temperature on surface tension for the selected ionic liquid, which was chosen as a possible new entrainer in extraction processes. The surface thermodynamic functions such as surface entropy and enthalpy have been derived from the temperature dependence of the surface tension values, as well as the critical temperature, parachor, and speed of sound for pure ionic liquid. The investigations include the effect of the alkyl chain length of an alcohol and polarity of a solvent on the surface tension.

Abstract  The barrier heights involved in the abstraction of a hydrogen atom from n-butanol by the hydroperoxyl radical have been computed with both compound (CBS-QB3, CBS-APNO, G3) and coupled cluster methods. In particular, the benchmark computations CCSD(T)/cc-pVTZ//MP2/6-311G(d,p) were used to determine that the barrier heights increase in the order alpha < gamma < beta < delta < OH. Two prereaction hydrogen-bonded complexes are formed, one of which connects the TGt conformer of n-butanol to the alpha and beta transition states and the other connects to the gamma and OH channels from the TGg conformer. Four postreaction complexes were also found which link the transition states to the products, hydrogen peroxide + C(4)H(9)O radical. Abstraction from the terminal delta carbon atom does not involve either a pre or postreaction complex. A number of DFT functionals-B3LYP, BMK, MPWB1K, BB1K, MPW1K, and M05-2X-were tested to see whether the correct ranking could be obtained with computationally less expensive methods. Only the later functional predicts the correct order but requires a basis set of 6-311++G(df,pd) to achieve this. However, the absolute values obtained do not agree that well with the benchmarks; the composite G3 method predicts the correct order and comes closest (< or = 2 kJ, mol (-1)) in absolute numerical terms for H-abstraction from carbon.

Abstract  The oxidation of n-propanol and n-butanol to their corresponding aldehydes was monitored by the pervaporation technique. Mass transfer phenomenon that occurs in the pervaporation process was confirmed by the results of inverse gas chromatography. Polydimethylsiloxane (PDMS), a hydrophobic polymer widely employed as a membrane in pervaporation technique, was evaluated as a stationary phase in this study. The retention times of the different molecules probes (n-propanol, n-butanol, propionaldehyde, and butyraldehyde), molecules involved as reactants and products in the oxidation reaction, gave an insight into the extent of the interactions between each of these molecules and the stationary phase. The infinite dilution conditions allowed to measure the infinite dilution activity coefficient, gamma(infinity), and the specific retention volume, V(g)(0), and to estimate the Flory-Huggins parameter interactions, chi(12)(infinity). The magnitudes of these parameters threw some light on the permselectivity of the membranes in the pervaporation operation.

Abstract  In the present work, we study the H atom abstraction reactions by hydroxyl radical at all five sites of 1-butanol. Multistructural variational transition state theory (MS-VTST) was employed to estimate the five thermal rate constants. MS-VTST utilizes a multifaceted dividing surface that accounts for the multiple conformational structures of the transition state, and we also include all the structures of the reactant molecule. The vibrational frequencies and minimum energy paths (MEPs) were computed using the M08-HX/MG3S electronic structure method. The required potential energy surfaces were obtained implicitly by direct dynamics employing interpolated variational transition state theory with mapping (IVTST-M) using a variational reaction path algorithm. The M08-HX/MG3S electronic model chemistry was then used to calculate multistructural torsional anharmonicity factors to complete the MS-VTST rate constant calculations. The results indicate that torsional anharmonicity is very important at higher temperatures, and neglecting it would lead to errors of 26 and 32 at 1000 and 1500 K, respectively. Our results for the sums of the site-specific rate constants agree very well with the experimental values of Hanson and co-workers at 896-1269 K and with the experimental results of Campbell et al. at 292 K, but slightly less well with the experiments of Wallington et al., Nelson et al., and Yujing and Mellouki at 253-372 K; nevertheless, the calculated rates are within a factor of 1.61 of all experimental values at all temperatures. This gives us confidence in the site-specific values, which are currently inaccessible to experiment.

Abstract  The aim of this study was to examine the interaction between amylose and 1-butanol during the 1-butanol-hydrochloric acid (1-butanol-HCl) hydrolysis of normal rice starch. The interaction model between amylose and 1-butanol was proposed using gas chromatography-mass spectrometry (GC-MS), (13)C cross polarization and magic angle spinning NMR analysis ((13)C CP/MAS NMR), differential scanning calorimetry (DSC), and thermalgravimetric analysis (TGA). GC-MS data showed that another form of 1-butanol existed in 1-butanol-HCl-hydrolyzed normal rice starch, except in the form of free molecules absorbed on the starch granules. The signal of 1-butanol-HCl-hydrolyzed starch at 100.1 ppm appeared in the (13)C CP/MAS NMR spectrum, indicating that the amylose-1-butanol complex was formed. DSC and TGA data also demonstrated the formation of the complex, which significantly affected the thermal properties of normal rice starch. These findings revealed that less dextrin with low molecular weight formed might be attributed to resistance of this complex to acid during 1-butanol-HCl hydrolysis.

Abstract  Product formation in the laser-initiated low-temperature (575-700 K) oxidation of n-butane was investigated by using tunable synchrotron photoionization time-of-flight mass spectrometry at low pressure (∼4 Torr). Oxidation was triggered either by 351 nm photolysis of Cl2 and subsequent fast Cl + n-butane reaction or by 248 nm photolysis of 1-iodobutane or 2-iodobutane. Iodobutane photolysis allowed isomer-specific preparation of either n-C4H9 or s-C4H9 radicals. Experiments probed the time-resolved formation of products and identified isomeric species by their photoionization spectra. For stable primary products of butyl + O2 reactions (e.g., butene or oxygen heterocycles) bimodal time behavior is observed; the initial prompt formation, primarily due to chemical activation, is followed by a slower component arising from the dissociation of thermalized butylperoxy or hydroperoxybutyl radicals. In addition, time-resolved formation of C4-ketohydroperoxides (C4H8O3, m/z = 104) was observed in the n-C4H9 + O2 and Cl-initiated oxidation experiments but not in the s-C4H9 + O2 measurements, suggesting isomeric selectivity in the combined process of the "second" oxygen addition to hydroperoxybutyl radicals and subsequent internal H-abstraction/dissociation leading to ketohydroperoxide + OH. To further constrain product isomer identification, Cl-initiated oxidation experiments were also performed with partially deuterated n-butanes (CD3CH2CH2CD3 and CH3CD2CD2CH3). From these experiments, the relative yields of butene product isomers (cis-2-butene, trans-2-butene, and 1-butene) from C4H8 + HO2 reaction channels and oxygenated product isomers (2,3-dimethyloxirane, 2-methyloxetane, tetrahydrofuran, ethyloxirane, butanal, and butanone) associated with OH formation were determined. The current measurements show substantially different isomeric selectivity for oxygenated products than do recent jet-stirred reactor studies but are in reasonable agreement with measurements from butane addition to reacting H2/O2 mixtures at 753 K.

Abstract  In aqueous binary mixtures, amphiphilic solutes such as dimethylsulfoxide (DMSO), ethanol, tert-butyl alcohol (TBA), etc., are known to form aggregates (or large clusters) at small to intermediate solute concentrations. These aggregates are transient in nature. Although the system remains homogeneous on macroscopic length and time scales, the microheterogeneous aggregation may profoundly affect the properties of the mixture in several distinct ways, particularly if the survival times of the aggregates are longer than density relaxation times of the binary liquid. Here we propose a theoretical scheme to quantify the lifetime and thus the stability of these microheterogeneous clusters, and apply the scheme to calculate the same for water-ethanol, water-DMSO, and water-TBA mixtures. We show that the lifetime of these clusters can range from less than a picosecond (ps) for ethanol clusters to few tens of ps for DMSO and TBA clusters. This helps explaining the absence of a strong composition dependent anomaly in water-ethanol mixtures but the presence of the same in water-DMSO and water-TBA mixtures.

Abstract  Smog chamber/FTIR techniques were used to determine rate constants of k(Cl+n-butanol) = (2.21 ± 0.38) × 10−10and k(OH+n-butanol) = (8.86 ± 0.85) × 10−12cm3molecule−1s−1in 700 Torr of N2/O2diluent at 296 ± 2K. The sole primary product identified from the Cl atom initiated oxidation of n-butanol in the absence of NO was butyraldehyde (38 ± 2%, molar yield). The primary products of the Cl atom initiated oxidation of n-butanol in the presence of NO were (molar yield) butyraldehyde (38 ± 2%), propionaldehyde (23 ± 3%), acetaldehyde (12 ± 4%), and formaldehyde (33 ± 3%). The substantially lower yields of propionaldehyde, acetaldehyde, and formaldehyde as primary products in experiments conducted in the absence of NO suggests that chemical activation is important in the atmospheric chemistry of CH3CH2CH(O)CH2OH and CH3CH(O)CH2CH2OH alkoxy radicals. The primary products of the OH radical initiated oxidation of n-butanol in the presence of NO were (molar yields) butyraldehyde (44 ± 4%), propionaldehyde (19 ± 2%), and acetaldehyde (12 ± 3%). In all cases, the product yields were independent of oxygen concentration over the partial pressure range of 10−600 Torr. The yields of propionaldehyde, acetaldehyde, and formaldehyde quoted above were not corrected for secondary formation via oxidation of higher aldehydes and should be treated as upper limits. The reactions of Cl atoms and OH radicals with n-butanol proceed 38 ± 2 and 44 ± 4%, respectively, via attack on the α-position to give an α-hydroxy alkyl radical which reacts with O2to give butyraldehyde. The results are discussed with respect to the atmospheric chemistry of n-butanol. [ABSTRACT FROM AUTHOR] Copyright of Journal of Physical Chemistry A is the property of American Chemical Society and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract  We here present a statistical model of hydrogen bond induced network structures in liquid alcohols. The model generalises the Andersson-Schulz-Flory chain model to allow also for branched structures. Two bonding probabilities are assigned to each hydroxyl group oxygen, where the first is the probability of a lone pair accepting an H-bond and the second is the probability that given this bond also the second lone pair is bonded. The average hydroxyl group cluster size, cluster size distribution, and the number of branches and leaves in the tree-like network clusters are directly determined from these probabilities. The applicability of the model is tested by comparison to cluster size distributions and bonding probabilities obtained from Monte Carlo simulations of the monoalcohols methanol, propanol, butanol, and propylene glycol monomethyl ether, the di-alcohol propylene glycol, and the tri-alcohol glycerol. We find that the tree model can reproduce the cluster size distributions and the bonding probabilities for both mono- and poly-alcohols, showing the branched nature of the OH-clusters in these liquids. Thus, this statistical model is a useful tool to better understand the structure of network forming hydrogen bonded liquids. The model can be applied to experimental data, allowing the topology of the clusters to be determined from such studies.

Abstract  With regard to the importance of butanol as a potential replacement or additive to fossil transportation fuels, a detailed understanding of butanol combustion chemistry is desirable. Routes to different isomers of butanol from biomass are becoming available, and it is known that the structure of fuel molecules can be of crucial importance with respect to the intermediate species pool and the nature and amount of potential pollutants, including regulated air toxics. Quantitative major and intermediate species profiles for the combustion of the four butanol isomers under low-pressure premixed flame conditions, measured with two different in situ mass spectrometric instruments have recently been reported (P. Osswald et al., Combust. Flame 158 (2011)2-15), and this large consistent dataset has motivated us to further develop a detailed and comprehensive chemical kinetic model which was used here to complement the experimental results with numerical simulations, including reaction flow analyses. The major differences in the overall chemical pathways in these flames will be discussed, especially with respect to the formation of undesired emissions, and from agreement and differences between experiment and model, suggestions for further work will be given. (C) 2012 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

Abstract  Absolute values of enthalpy and Gibbs free energy of hydration (h) or solvation (s) of H+ ion, Delta H degrees(H+)(h or s) and Delta G degrees(H+)(h or s) in aqueous and non-aqueous solvents (methanol, ethanol, n-propanol, iso-propanol, n-butanol, t-butanol, ethylene glycol, propylene carbonate, n-methyl formamide, acetone, tetrahydro furan, 1,4-dioxan, acetonitrile) were determined directly using a single standard state [i.e.H-2(g) at lbar and 298.15K]. A comparative study of the methods of Tissandier et al. and the present one has been made. The values -1299.4 kJ mol(-1) (-1303.9 kJ mol(-1)) and -1284.5 kJ mol(-1) (-1288.9 kJ mol(-1)) for the absolute enthalpy [Delta H-b degrees(H+)] and Gibbs free energy [Delta G(h)degrees(H+)] of hydration determined in the present work have been found to be much lower than the corresponding values -1150.1+/-0.9 kJ mol(-1) and -1104.5+/-0.3 kJ mol(-1) determined by Tissandier et al. using cluster-ion solvation data. The values of Tissandier et al. have been acclaimed to be the most accurate values of these quantities by most of the workers. However, the method is based on approximations and assumptions and uses a number of conventional standard states. The calculations use the principle of ionic additivity and Klot's equation which are open to question. The equations, based on the difference between several sets of energy values of different ion-pairs of similar magnitude, have been used. Thus, the method is insensitive and many of the important energy terms characterizing the ions and the structure of the solvents are eliminated. Thus the accuracy of the energy values are not without question. Our method, on the other hand, is a direct one using a single standard state. The most important contributory factor for the determination of Delta G(h)degrees(H+) is the Gibbs free energy of charging and the value is accurately known. Thus, the values for Delta H-h degrees(H+)) and Delta G(h)degrees(H+) determined by its though much lower than those of Tissandier et al. can be regarded to be reasonable.

Abstract  Carboethoxycarbene reacts with methanol-OD to form an ylide. The formation and decay of this ylide was monitored by ultrafast time-resolved IR spectroscopy. The formation and decay of the ylide is linearly dependent on the concentration of methanol-OD in acetonitrile with second-order rate constants of ylide formation (8.4 × 10(9) M(-1) s(-1)) and decay (1.4 × 10(9) M(-1) s(-1)). Similar results were obtained with 1-butanol.

Abstract  NO formation and flame propagation are studied in premixed flames of iso- and n-isomers of butane and butanol through experimental measurements and direct simulation of experimental profiles. The stabilized flame is realized through the impingement of a premixed combustible jet from a contraction nozzle against a temperature-controlled plate. The velocity field is obtained by means of Particle Image Velocimetry (PIV) and nitric oxide concentration profiles are measured using Planar Laser Induced Fluorescence (PLIF), calibrated using known NO seeding levels. It is found that NO formation in n- and iso-isomers is comparable under the conditions considered, except for rich butanol mixtures, whereby NO formation is higher for iso-butanol. Generally, less NO is formed in butanol flames than in the butane flames. The experiment is simulated by a 1D chemically reacting stagnation flow model, using literature models of C1-C4 hydrocarbons [Wang et al., 2010] and butanol combustion chemistry [Sarathy et al., 2009, 2012]. NO prediction is tested using two of these mechanisms with a previously-published NOx submechanism added into the butane and butanol models. While a good level of agreement is observed in the velocity field prediction under lean and stoichiometric conditions, discrepancies exist under rich conditions. Greater discrepancies are observed in NO prediction, except for the C1-C4 mechanism which shows good agreement with the experiment under lean and stoichiometric conditions. The current study provides data for further development of mechanisms with NOx prediction capabilities for the fuels considered here. (C) 2012 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

Abstract  The efficient one-step conversion of n-butanol to iso-butene over zeolite catalysts by combined dehydration and isomerisation has been demonstrated. The medium pore-size unidirectional channel zeolites Theta-1 and ZSM-23 show high conversion and stable selectivity to iso-butene.

Abstract  Transient receptor potential ankyrin 1 (TRPA1) is a calcium-permeable non-selective cation channel that is mainly expressed in primary nociceptive neurons. TRPA1 is activated by a variety of noxious stimuli, including cold temperatures, pungent compounds such as mustard oil and cinnamaldehyde, and intracellular alkalization. Here, we show that primary alcohols, which have been reported to cause skin, eye or nasal irritation, activate human TRPA1 (hTRPA1). We measured intracellular Ca(2+) changes in HEK293 cells expressing hTRPA1 induced by 1 mM primary alcohols. Higher alcohols (1-butanol to 1-octanol) showed Ca(2+) increases proportional to the carbon chain length. In whole-cell patch-clamp recordings, higher alcohols (1-hexanol to 1-octanol) activated hTRPA1 and the potency increased with the carbon chain length. Higher alcohols evoked single-channel opening of hTRPA1 in an inside-out configuration. In addition, cysteine at 665 in the N terminus and histidine at 983 in the C terminus were important for hTRPA1 activation by primary alcohols. Furthermore, straight-chain secondary alcohols increased intracellular Ca(2+) concentrations in HEK293 cells expressing hTRPA1, and both primary and secondary alcohols showed hTRPA1 activation activities that correlated highly with their octanol/water partition coefficients. On the other hand, mouse TRPA1 did not show a strong response to 1-hexanol or 1-octanol, nor did these alcohols evoke significant pain in mice. We conclude that primary and secondary alcohols activate hTRPA1 in a carbon chain length-dependent manner. TRPA1 could be a sensor of alcohols inducing skin, eye and nasal irritation in human.