Lower Aliphatic Alcohols Research Articles

Palladium-catalyzed oxidation of lower aliphatic alcohols with oxygen in the presence of aromatic nitriles in aqueous medium

The kinetics of oxidation of lower aliphatic alcohols (C1–C4) to the corresponding carbonyl compounds with oxygen in the presence of palladium(II) tetraaqua complex and aromatic nitriles (benzonitrile, phenylacetonitrile, and o-tolunitrile) in aqueous medium (c = 0.01 M) at 65°C under atmospheric pressure were studied. A probable reaction mechanism and kinetic equation were proposed. Aromatic nitriles were found to stabilize decomposition of low-valence palladium species, ensuring activation of molecular oxygen and subsequent oxidation of alcohols.

Calcium-promoted Catalytic Degradation of PCDDs, PCDFs, and Coplanar PCBs under a Mild Wet Process

The authors achieved highly efficient degradation of polychlorinated aromatic compounds, including polychlorinated dibenzo-p-dioxins, dibenzofurans, and dioxin-like compounds such as coplanar polychlorinated biphenyls (co-PCBs), which are known as persistent organic pollutants. Degradation was accomplished in 24 h through a simple stirring operation using safe and high workability metallic calcium, which acts as both a scavenger and a reducing agent, and Rh/C catalyst in an alcohol solution under mild conditions in a sealed tube at 25 degrees C without a temperature increase within 0.15 MPa of increasing internal pressure during the reaction. In this system, reductive dechlorination by metallic calcium and catalytic reduction by Rh/C and generated hydrogen gas, without any external addition of hydrogen, exert a synergistic effect on the degradation of chlorinated compounds. Alcohol was used as a proton source and hydrogen, which was generated by a side reaction, causes an increase in the activity of Rh/C catalyst. Through the degradation of 4-chloroanisole in ethyl alcohol, anisole and cyclohexyl methyl ether were obtained in good conversions. Using ethyl alcohol as a solvent, treatment of dioxins and co-PCBs in a solution was markedly effective for degradation to reduce 2806 pg TEQ/ml of initial concentration to 31.8 pg TEQ/ml; its yield was 98.5%. Moreover, degradation in methyl alcohol took place in a 99.3% yield. That concentration ultimately reached 20.3 pg TEQ/ml under a mild wet process. All congeners of dioxins and co-PCBs were degraded in high conversions. In this degradation, lower aliphatic alcohol, such as methyl alcohol, is effective for making a new calcium surface as compared to alcohol with more methylene chains. In addition, it seemed that a higher pressure of hydrogen was easily generated in methyl alcohol, and then catalytic degradation was effectivley influenced.

Capillary electrophoretic separation of vitamins in sodium dodecyl sulfate containing buffers with lower aliphatic alcohols and n-hexane as organic modifiers

The effect of lower organic alcohols as co-surfactants (methanol, ethanol, n-propanol, isopropanol, propanediol, n-butanol and isoamylalcohol) and n-hexane as an organic modifier in 12.5 mol/l phosphate buffer with varying SDS concentration was investigated using a set of vitamins and p-hydroxybenzoic acid as the test mixture. It was demonstrated that optimum separations can be achieved particularly at high concentrations of the surfactant; the selectivity can be changed by adding a co-surfactant; while propanol and isopropanol show the same properties as co-surfactants, the most efficient alcohols were isoamylalcohol and propanediol. n-Butanol was capable of selective separation of p-hydroxybenzoic acid in the test mixture. Addition of ethanol appears most effective at higher concentrations (while all the other alcohols are effective already at 5% concentration, the best results with ethanol were obtained when it constituted 20% of the background electrolyte). 5% Concentration of methanol resulted in poor separation of the test mixture, however if 300 μl/10 ml of hexane were added to 20 mmol/l SDS containing phosphate buffer, the resulting separation was practically the same as with 50 mmol/l SDS.

Mechanism of the Oxidation of Lower Aliphatic Alcohols with Catalysis by Giant Pd-561 Clusters

The mechanism of oxidation of lower aliphatic alcohols by oxygen in solutions of giant Pd-561 clusters was examined. The mechanism involves the formation of two types of intermediate particles on the surface of the metal cluster. Their further transformations involve interaction with the external substrates.

Preparation of ω‐hydroxynonanoic acid and its ester derivatives

AbstractMethyl ricinoleate was ozonized in methanol or in acetic acid and the intermediate hydroperoxides were reduced electrochemically on Pb‐cathode to give 9‐hydroxynonanoic acid 1 in high yields. The acid 1 was also prepared by direct castor oil ozonolysis in methanol followed by sodium borohydride reduction of the intermediate hydroperoxides. The cost of the electricity for the electroreduction was at least 30 times lower as compared with sodium borohydride consumption. 9‐Hydroxynonanoic acid was then transformed to alkyl 9‐acetoxynonanoates 3a–3d, for which 1H nuclear magnetic reasonance, mass, and infrared spectra are given. Esterification of the hydroxy acid 1 with boric acid and pyrolysis of the resultant orthoborates produced 8‐nonenoic acid 4 in a 45% yield. Reaction of 4 with lower aliphatic alcohols in presence of Amberlyst 15 produced alkyl 8‐noneates 5a–5d along with some amounts of a cis/trans mixture of alkyl 7‐noneates.

High‐Yield Recovery of Xanthan by Precipitation with Isopropyl Alcohol in a Stirred Tank

AbstractMicrobial polysaccharides (xanthan being the most successful example) are important commercial products having a wide range of applications in a variety of industries. Production processes of xanthan typically involve aseptic fermentation and a number of downstream operations. A key issue in the economics of the production of biopolymers such as xanthan is its recovery. This operation is commonly performed by precipitation with low molecular weight aliphatic alcohols. In this work, three particular aspects were evaluated: the effect of the electrolyte concentration (KCl), the amount of alcohol, and the heat treatment of the fermentation broths on the precipitation yield and on the quality of the final product. A Rushton turbine and a marine propeller were used as mixing devices. Dehydrated−reconstituted fermentation broths to which the ionic strength was adjusted (with NaCl) to a value close to that exhibited by an actual broth, behaved&—;from the precipitation point of view&—;as fresh broths. The Rushton turbine gave slightly higher yields as stirring speed was higher. On the other hand, the marine propeller showed a pronounced drop in yield as stirring speed was increased. In both cases, composition analysis (xanthan as equivalent sugars, nitrogen, and ash) revealed that lower yields were associated with higher precipitate purities. This means that mixing conditions importantly determine the quality of the product and can be fixed to meet a given specification. However, it is clear that a compromise has to be established between quantity and quality. The heat treatment applied to the broths substantially improved the precipitation yields, compared with nontreated broths. On the basis of precipitable solids, using 2% (w/wgum) KCl as a electrolyte and two volumes of alcohol per volume of broth, a recovery of 80% was achieved in the heat‐treated broths (as compared with 65% in the nontreated broths). When 2 volumes of alcohol per volume of broth were used, the increase of electrolyte (KCl) concentration from 2% (w/wgum) to 3% increased precipitation yield (on the basis of precipitable solids) from 70 to 80%. Increasing further the electrolyte concentration (up to 5%, w/wgum) improved the yield only slightly. In general, the effect of KCl concentration on the precipitation y ield was very similar in heat‐treated broths than in nontreated broths. When 3% (w/wgum) KCl was used as electrolyte and 1:1.4 volumes of alcohol per volume of broth were employed in order to precipitate xanthan from heat‐treated, reconstituted broths (containing 25 kg m−3 of xanthan), yields up to 99% (based on xanthan) were achieved.

Preparation and characterization of Nafion powders for low cost PEFC electrode production

In recent years there has been an increasing interest in cation conducting materials, as these are one of the promising concepts for polymer electrolyte fuel cells (PEFC). In ongoing fuel cell research these materials are used either as a membrane or as a 5 wt.% solution in a mixture of lower aliphatic alcohols. As part of the fuel cell research at the DLR, Nafion powder was prepared by grinding Nafion beads in a ball mill under nitrogen cooling. The influence of different grinding parameters and the cationic group of the polymer on the resulting powder was examined.

Effect of low molecular weight aliphatic alcohols and related compounds on platelet factor 4 subunit association

Titration of platelet factor 4 (PF4) with increasing concentrations of various low molecular weight aliphatic alcohols disrupts dimer and tetramer quaternary structure while preserving tertiary structural integrity. Normally observed slow subunit exchange (1H NMR time scale) is shifted into the fast chemical exchange regime. The order of effectiveness is butanol > 2-propanol > propanol > ethanol > methanol. Fluorination of ethanol (trifluoroethanol) and 2-propanol (hexafluoro-2-propanol) increases effectiveness by approximately 2 orders of magnitude. Oxidation to 2-propanone or trifluoro-2-propanone produces a less effective compound, suggesting a mechanistic role for the hydroxyl group. Increasing the number of hydroxyls to three, as in glycerol, however, is relatively ineffective in disrupting aggregate states or modifying subunit exchange rates. While 19F NMR studies indicate that these alcohols specifically interact with PF4, binding alone can not explain their mechanism of action. Dimethyl sulfoxide, structurally similar to 2-propanol, disrupts PF4 aggregation by direct binding, but does not shift subunit exchange kinetics into the NMR fast-exchange regime. Although not fully understood, the effectiveness of these compounds appears to be related to the colligative properties of the solution.

Transients formed during reduction of polynuclear aromatics: a pulse radiolysis study

Pulse radiolysis studies of the reduction of polynuclear aromatic hydrocarbons naphthalene, anthracene, pyrene and pentacene (ArH) with solvated electron and H atom have been carried out on the nanosecond time scale, using 7 MeV electron pulses in polar organic solvents, both protic and aprotic. Kinetic results of reactions of ArH with e–solv show high reactivity (k ca. 1010 dm3 mol–1 s–1) to form the respective radical anions (ArH˙–), with increasing yields in the presence of primary low molecular weight aliphatic amines and alcohols. In an attempt to follow the individual radical anion reactivity in these solvents, their decay to form the respective monohydro radicals (ArH2˙) were observed. The measured pseudo-first-order formation rate constants of the respective ArH2˙(Kfca. 105 to 103 s–1) indicate that, in the presence of dissolved alkali metal in THF and amines/ammonia, as in the Birch synthesis, the reduction of these hydrocarbons follows this mechanism.

Etherification of propylene oxide with lower aliphatic alcohols

Etherification of propylene oxide with lower aliphatic alcohols

Steady-state and transient kinetics of displacement adsorption and educt inhibition in dehydration of alcohols on alumina

Alumina-catalyzed alkene formation from low aliphatic alcohols has been used as an example of systems showing both 1patiev displacement adsorption and educt inhibition. The numerically simulated steady-state and the transient kinetic data obtained in the CSTR approximation qualitatively agree with the experimental ones. The Ipatiev-Hinshelwood steady-state and the dynamic models provide close predictions at higher partial pressures of alcohol and under the influence of water m the feed.

THE DISTRIBUTION OF NOR-α-AMINOACIDS IN LIQUID TWO-PHASE TERNARY SYSTEMS FORMED BY SALTING-OUT OF LOW ALIPHATIC ALCOHOLS FROM AQUEOUS SOLUTIONS.

Abstract It is shown that the distribution of homologous series of nor-α-aminoacids in liquid two-phase three-component systems formed by salting-out of low aliphatic alcohols from their aqueous solutions by sodium chloride can be described by the following relation: 6nZ)=a + bln φ, where: D is the distribution coefficient expressed as the ratio of concentration of aminoacid in the upper and lower phases, respectively; φ is the ratio of alcohol concentration expressed in molar percent in the same phases; a and b are constants related to activity coefficients and salting-out constants of aminoacid and alcohol by sodium chloride.

穏やかな条件下でのシリカ表面のアルコキシ化

Surface alkoxyl reaction of silica gels was investigated under ordinary contact with some of the low molecular weight saturated aliphatic alcohols. Silica gels were in contact with liquid alcohols by using Soxhlet's extractor below their boiling points. The degree of alkoxylation for surface hydroxyls was examined by an infrared spectra and with T. G, analysis. It was shown that some of the surface hydroxyls were easily esterified to alkoxyl groups even by contact with alcohols under ordinary conditions.Adsorption isotherms of methanol vapor at room temperature (25°C) were measured on silica samples which were previously activated at various temperatures. Adsorption equilibria depend upon the pre-treated temperature, and surface methylation reaction took place not only on surface hydroxyls but also on siloxane bridges even at room temperature.

4845033 Process for a continuous fermentative production of low aliphatic alcohols or organic solvents: Uwe Tegtmeier, Braunschweig, Federal Republic Of Germany assigned to Starcosa GmbH

4845033 Process for a continuous fermentative production of low aliphatic alcohols or organic solvents: Uwe Tegtmeier, Braunschweig, Federal Republic Of Germany assigned to Starcosa GmbH

Degradation of aliphatic alcohols by human liver alcohol dehydrogenase: effect of ethanol and pharmacokinetic implications.

We have investigated the oxidation of low molecular weight aliphatic alcohols by Class I, II, and III alcohol dehydrogenases (ADH) isolated from human liver. These alcohols are generally present as byproducts of alcoholic beverages and referred to as alcoholic congeners. At concentrations corresponding to those in the blood after ingestion of alcoholic drinks (10-100 microM), the oxidation of propanol-1, isobutanol, 2-methylbutanol-1, and 3-methylbutanol-1 was mediated mainly by the isoenzymes of class I ADH, whereas butanol-1 was metabolized by Class I and II ADH. Class II ADH showed no activity with any of the alcohols at concentrations up to 100 microM. Lineweaver-Burk plots of the Class I ADH-catalyzed oxidation of all the congeners tested were linear in the pharmacokinetically relevant concentration range between 10 and 100 microM. Ethanol at concentrations found in the blood after moderate drinking (2.5-10 mM) caused a concentration-dependent inhibition of the congener oxidation. The experimentally determined kinetic constants were used to simulate the pharmacokinetics of propanol-1 metabolism in a multicompartment model system which accounts for first-pass elimination. The results suggest, in agreement with reported data from drinking experiments, that congener alcohols undergo considerable metabolism during the first liver passage, the extent of the first-pass metabolism depending on the ethanol dose.

Seed-germination inhibition by volatile alcohols and other compounds associated withAmaranthus palmeri residues

Effects of 3-pentanone and eight low molecular weight aliphatic alcohols and aldehydes identifed in the mixtures of volatiles released byAmaranthus palmeri S. Wats. (AMAPA) residues were determined on germination of onion, carrot, AMAPA, and tomato seeds. Three-day exposures to these volatiles significantly inhibited germination of these assay seeds, and the inhibition was dependent upon exposure time and concentration. Based on the degree of inhibition observed in both time- and concentration-dependent assays, the following activity series was obtained: 2-heptanol > 3-methyl-1-butanol, 1-hexanol > hexanal, 1-pentanol, 3-pentanone, acetaldehyde > ethanol, 2-methyl-1-propanol. The activities of this group of compounds with that of 2-heptanone appear to be additive and related to test compound volatility and hydrophilicity. 2-Heptanol and 2-heptanone also significantly inhibited the germination of other species, including shepherdspurse, soybean, lettuce, alfalfa, common purslane, oats, and lovegrass.

Substrate Specificity of Human Cutaneous Alcohol Dehydrogenase and Erythema Provoked by Lower Aliphatic Alcohols

The substrate utilization rates of human cutaneous alcohol dehydrogenase were determined for 7 lower aliphatic primary alcohols: ethanol, propanol, butanol, pentanol, 2-methylpropanol, 3-methylbutanol, and 2,2-dimethyl-propanol. 1-Pentanol gave the highest relative activity and 2,2-dimethylpropanol the lowest. The frequency of erythemogenesis was determined in vivo for these 7 lower aliphatic primary alcohols. The frequency of erythemogenesis correlated strongly and significantly with the rate of substrate utilization by alcohol dehydrogenase. These results are consistent with the view that the reaction to primary alcohols applied topically to human skin is provoked, in large part, by the corresponding aldehyde.

Excess volumes of (2-butanol + water) at pressures up to 220 MPa

Densities of (2-butanol + water) at ambient pressure are reported together with excess molar volumes at pressures from ambient to 220 MPa for temperatures in the range 274 to 358 K. The behaviour is found to be similar to that of other (lower aliphatic alcohol + water) mixtures under similar conditions.

Kinetics of dehydrogenation of low aliphatic alcohols on copper catalysts containing small amounts of Cr, Mn, Fe and Ni

The apparent activation energy of dehydrogenation of ethyl, n-propyl, i-propyl, n-butyl and 2-butyl alcohols on Cr, Mn, Fe and Ni catalysts was correlated with the connectivity index of reactant molecule and the magnetic susceptibility of the catalyst. The dehydrogenation reaction seems to be favored by increasing catalyst paramagnetism.

Optical coatings formulations containing tetrafluoroethylene

Two optical reference coatings containing tetrafluorethylene have been formulated using silicone binders. One of the silicones used is an oligomer of methyl silanol supplied at 48 percent solids in a mixture of butanol and ethanol. The other silicone is a proprietory silicone tethered ethyl silicate based colloidal silica binder supplied at 22 and 36 percent solids in a mixture of low molecular weight aliphatic alcohols. The coatins are characterized by high durability and have an overall reflectance in the visible part of the spectrum of about 90 percent. The substrate preparation and application procedures are described.