Effect Of Alcohol Addition Research Articles

5-1-1 バイオディーゼル燃料の液滴燃焼過程におけるアルコール混入の影響(5-1 燃焼,Session 5 燃焼・微粒化,研究発表)

5-1-1 バイオディーゼル燃料の液滴燃焼過程におけるアルコール混入の影響(5-1 燃焼,Session 5 燃焼・微粒化,研究発表)

Dechlorination of organic chlorides with supported noble-metal catalysts in alkaline 2-propanol: effect of alcohol additives

m- and p-Chloroanisole were dechlorinated in the presence of a supported noble-metal catalyst (Pd/C or Rh–Pt/C) at 30 °C in a solution of 2-propanol containing NaOH. The addition of a small amount of methanol (1% v/v) to the 2-propanol solution greatly enhanced the rate of dechlorination of p-chloroanisole with Pd/C but retarded the rate with Rh–Pt/C. Other primary alcohols (1% v/v) enhanced m-chloroanisole dechlorination over Pd/C in the following order: methanol (enhancement factor, 10.6) > ethanol (3.3) > 1-propanol (2.1) > 1-butanol (1.0). When a secondary alcohol (2-butanol), tertiary alcohol (t-butyl alcohol), diol (ethylene glycol), or triol (glycerin) was added at 1% (v/v), the dechlorination rates were unchanged or retarded. We found that Pd/C was activated effectively by pretreatment with a solution of 2-propanol/methanol (99:1 v/v) containing NaOH.

Micellization and micellar growth of alkanediyl-α,ω-bis(dimethyldodecylammonium bromide) surfactants in the presence of medium-chain linear alcohols

Micellization and micellar growth of cationic dimeric surfactants of the alkanedyil-α,ω-bis(dimethyldodecylammonium) bromide type, 12- s-12,2Br − ( s = 3, 4, 6), in the presence of various amounts of 1-butanol, 1-pentanol, and 1-hexanol have been investigated. The influence of the nature and concentration of alcohol on the cmc, on the micellar ionization degree, on the average micellar aggregation number, and on the polarity of the micellar interfacial region was investigated by using conductivity and fluorescence measurements. Subsequently, effects of alcohol addition on the surfactant concentration range where sphere to rod transitions occur were examined and information about changes in the micropolarity and in the microviscosity accompanying the morphological transition was obtained. The experimental results were explained by considering the variations in the different contributions to the Gibbs energy of micellization caused by the presence of alcohols. The study of the reaction methyl naphthalene-2-sulfonate + Br − in some water–alcohol 12-6-12,2Br − micellar solutions provided information about the characteristics of the dimeric micelles as microreactors and show the complexity of the microheterogeneous systems studied.

Effect of alcohol addition on electroplating of iridium

The effect of some alcohols as additives on the electroplating of iridium in an electrolyte composed of 52 mmol dm−3 sodium hexabromoiridate(III), 0·5 mol dm−3 sodium bromide and 0·5 mol dm−3 sodium sulphate was examined. The addition of alcohols such as 1-butanol, 2-butanol, ethylene glycol and glycerol could significantly keep the current efficiency of iridium plating high during the plating time. The decrease in the current efficiency with increasing plating time in the absence of alcohol was due to the increase in the concentration of hexabromoiridate(IV) ion which was formed by the oxidation of hexabromoiridate(III) ion at the anode and diffused into the electrolyte solution. When an alcohol was added, the hexabromoiridate(IV) ions were chemically reduced back to the hexabromoiridate(III) ions by the alcohol in the electrolyte solution.

Characterization and Demulsification of Water-in-crude Oil Emulsions

Many advances have been made in the field of emulsions in recent years. Emulsion behavior is largely controlled by the properties of the adsorbed layers that stabilized the oil-water surfaces. The effect of chemical demulsifiers in demulsification of water-in-crude oil emulsions were assessed experimentally. The relative rates of water separation were characterized via graduated beakers. Four groups of demulsifier with different functional groups were used in this work namely amines, polyhydric alcohol, sulphonate and polymer. The effect of alcohol addition on demulsification performance also studied. The results obtained in this study have exposed the capability of chemical demulsifiers in destabilization of water-in-crude oil emulsions. Further works are nevertheless required to provide deeper understanding of the mechanisms involved to facilitate the development of an optimum system applicable to the industry.

Kinetic Effects of Alcohol Addition on the Anodic Behavior of Silicon in Acid Fluoride Media

The anodic dissolution of silicon in acid solutions of ammonium fluoride is investigated in aqueous and water-alcohol media by rotating disk voltammetry and impedance spectroscopy. The voltammograms recorded in water-alcohol media show, in comparison to water, the following effects: an increase of the dissolution currents measured at pH>2 and an opposite effect at pH<2; a distortion of the curve, with a relative increase of the characteristic currents in the region of low applied potentials, indicating easier dissolution of the "wet" oxide forming under those conditions; a shift of the maximum of the current-pH curves from about pH 3 in water to about pH 4 in 50% ethanol v/v. Analysis of impedance data at pH values 4-5 in water and water-ethanol media show similar dependence on potential for the parameters Chf (high-frequency capacitance) and RhfI (Rhf is a high-frequency resistance and I is the steady state current), suggesting the formation of oxide films with similar properties. The marked differences of anodic behavior in the two types of media are discussed and explained in terms of the effects of alcohol addition on the speciation equilibria of hydrofluoric acid and on the kinetic rate constants of dissolution of the surface oxide layer.

Copolymerization of Cyclohexene Oxide with CO2 by Using Intramolecular Dinuclear Zinc Catalysts

The intramolecular dinuclear zinc complexes generated in situ from the reaction of multidentate semi-azacrown ether ligands with Et(2)Zn, followed by treatment with an alcohol additive, were found to promote the copolymerization of CO(2) and cyclohexene oxide (CHO) with completely alternating polycarbonate selectivity and high efficiency. With this type of novel initiator, the copolymerization could be accomplished under mild conditions at 1 atm pressure of CO(2), which represents a significant advantage over most catalytic systems developed for this reaction so far. The copolymerization reaction was demonstrated to be a living process as a result of the narrow polydispersities and the linear increase in the molecular weight with conversion of CHO. In addition, the solid-state structure of the dinuclear zinc complex was characterized by X-ray crystal structural analysis and can be considered as a model of the active catalyst. On the basis of the various efforts made to understand the mechanisms of the catalytic reaction, including MALDI-TOF mass analysis of the copolymers' end-groups, the effect of alcohol additives on the catalysis and CO(2) pressure on the conversion of CHO, as well as the kinetic data gained from in situ IR spectroscopy, a plausible catalytic cycle for the present reaction system is outlined. The copolymerization is initiated by the insertion of CO(2) into the Zn--OEt bond to afford a carbonate-ester-bridged complex. The dinuclear zinc structure of the catalyst remains intact throughout the copolymerization. The bridged zinc centers may have a synergistic effect on the copolymerization reaction; one zinc center could activate the epoxide through its coordination and the second zinc atom may be responsible for carbonate propagation by nucleophilic attack by the carbonate ester on the back side of the cis-epoxide ring to afford the carbonate. The mechanistic implication of this is particularly important for future research into the design of efficient and practical catalysts for the copolymerization of epoxides with CO(2.).

Kinetics and Mechanism of l-Lactide Polymerization by Rare Earth Metal Silylamido Complexes: Effect of Alcohol Addition

The ring-opening polymerization of l-lactide initiated by rare earth metal silylamido complexes [Ln(OSSO){N(SiHMe2)2}(THF)] (1−3: Ln = Y, Lu; OSSO = 1, ω-dithiaalkanediyl-bridged bisphenolato) was studied. MALDI-TOF mass spectrometry and 1H NMR spectroscopy suggested that the polymerization proceeded via a conventional coordination−insertion mechanism involving silylamide ligand as the initiating group and the cleavage of acyl−oxygen bond of the monomer. A two-stage linear relationship between ln([LA]0/[LA]t) and the polymerization time was observed for the yttrium complex [Y(pdtbp){N(SiHMe2)2}(THF)] (pdtbp = 1,5-dithiapentanediyl-bis{4,6-di-tert-butylphenolato}, 3). In both stages, the polymerization showed first-order kinetics for the monomer concentration. The first-order dependency of the initiator concentration was only observed when the monomer conversion to PLA was less than 50−60%. The aggregation of the active growing polymer chain into dimeric structure occurred in the second stage. In contrast...

Influence of alcohol addition on gas hold-up, liquid circulation velocity and mass transfer coefficient in a split-rectangular airlift bioreactor

In this work, the effect of alcohol addition on gas hold-up, liquid circulation velocity and gas–liquid volumetric mass transfer coefficient was studied in a split-rectangular airlift bioreactor using air-water as a system to which propanol was added in concentrations ranging from 0.01 to 0.1% (v/v). In order to compare the effect of the propanol with other alcohols, methanol and butanol were also used. The experimental results showed that, at high superficial gas velocities, the addition of small amounts of alcohols decreases the difference between the gas hold-up in the riser and the downcomer, which is due to smaller bubble diameter than with the tap water system. This behaviour is enhanced by alcohols with long carbon chain lengths, which has been explained on the basis of surface tension effects. As a result, the addition of alcohol solutions results in a significant decrease in the liquid circulation velocity, which is mainly due to the decrease in the circulation driving force, but also in a strong decrease in the volumetric gas–liquid mass transfer coefficient for superficial gas velocities higher than 0.033 m/s. This surprising result has been explained by a strong decrease in K L values due to the presence of alcohol and by oxygen depletion due to the increasing amount of small recycled bubbles at high superficial gas velocity.

亜鉛電解採取における電解液中へのアルコール類添加による電解挙動

亜鉛電解採取における電解液中へのアルコール類添加による電解挙動

The effect of alcohol additives on etching characteristics in KOH solutions

Abstract Different alcohol additives to KOH solution have been studied. It was stated that the alcohols result in changing silicon etching anisotropy. The alcohols with one hydroxyl group exhibited similar effect as isopropyl alcohol. They caused strong reduction of etch rates of (h h 1) type planes, usually developing at the side-walls of etched convex figures. This was the reason of the reduction of convex corner undercut. The alcohols with more than one hydroxyl group did not influence the etching anisotropy and caused deterioration of surface finish. The connection of alcohol properties with (h h 1) etch rate reduction have been analysed. It has been stated that the advantageous effect of the alcohols from propanol and butanol groups is connected with their low surface tension.

Effect of alcohol addition on the movement of petroleum hydrocarbon fuels in soil.

Groundwater contamination by fuel spills from aboveground and underground storage tanks has been of growing concern in recent years. This problem has been magnified by the addition of oxygenates, such as ethanol and methyl-tertiary-butyl ether (MTBE) to fuels to reduce vehicular emissions to the atmosphere. These additives, although beneficial in reducing atmospheric pollution, may, however, increase groundwater contamination due to the co-solvency of petroleum hydrocarbons and by the provision of a preferential substrate for microbial utilisation. With the introduction of ethanol to diesel fuel imminent and the move away from MTBE use in many states of the USA, the environmental implications associated with ethanol additive fuels must be thoroughly investigated. Diesel fuel movement was followed in a 1-m soil column and the effect of ethanol addition to diesel fuel on this movement determined. The addition of 5% ethanol to diesel fuel was found to enhance the downward migration of the diesel fuel components, thus increasing the risk of groundwater contamination. A novel method using soil packed HPLC columns allowed the influence of ethanol on individual aromatic hydrocarbon movement to be studied. The levels of ethanol addition investigated were at the current additive level (approx. 25%) for ethanol additive fuels in Brazil and values above (50%) and below (10%) this level. An aqueous ethanol concentration above 10% was required for any movement to occur. At 25% aqueous ethanol, the majority of hydrocarbons were mobilised and the retention behaviour of the soil column lessened. At 50% aqueous ethanol, all the hydrocarbons were found to move unimpeded through the columns. The retention behaviour of the soil was found to change significantly when both organic matter content and silt/clay content was reduced. Unexpectedly, sandy soil with low organic matter and low silt/clay was found to have a retentive behaviour similar to sandy subsoil with moderate silt/clay, but little organic matter. It was concluded that sand grains might have a more important role in the adsorption of petroleum hydrocarbons than first realised. This method has shown that soil packed HPLC columns can be used to provide a quick estimate of petroleum hydrocarbon, and possibly other organic contaminant, movement in a variety of different soil types.

Effects of Alcohol Addition on Gelation in Aqueous Solution of Poly(ethylene oxide)-Poly(propylene oxide)-Poly(ethylene oxide) Triblock Copolymer

We are very grateful for the financial aid from the Ministry of Education of Korea through the Brain Korea 21 Program at Seoul National University.

Preparation of Ultrafine Titanium Dioxide Particles Using Hydrolysis and Condensation Reactions in the Inner Aqueous Phase of Reversed Micelles: Effect of Alcohol Addition

An attempt was made to prepare ultrafine titanium dioxide (TiO2) particles in the nanometer range by making use of the hydrolysis and condensation reactions of tetraisopropylorthotitanate (TTIP) in the inner aqueous phase of Aerosol OT reversed micelles formed in cyclohexane. Addition of linear alcohols (C2 to C6) to TTIP was found to affect the size of the titanium dioxide particles formed. The particle size was strongly dependent on the alkyl chain length and the amount of the alcohols. Addition of alcohols with the alkyl chain length smaller than 1-butanol increased the size of the particles over that prepared without alcohol addition, while addition of alcohols with a moderately long alkyl chain, like 1-pentanol and 1-hexanol, caused a decrease in the particle size. In particular, addition of 1-hexanol was found to yield TiO2 particles with a best dispersibility and sizes of around 10 nm.

Effects of Alcohol Addition on the Deposition of Diamond Thick Films by dc Plasma Chemical Vapor Deposition Method

Diamond films have been deposited by dc plasma chemical vapor deposition method. The addition of alcohol in the resource gas largely increases the deposition rate. The effects of alcohol addition on deposition rate and film quality are analyzed by scanning electron microscopy and Raman spectrometry. The mechanism of experimental phenomena is discussed.

Effect of alcoholic additives on the nucleation of KDP and DKDP crystals

The nucleation of KDP and DKDP crystals from aqueous solutions was studied in the presence of alcoholic additives. Induction periods for nucleation as a function of supersaturation in different alcoholic additives were measured. The surface free energy, Gibbs free energy and radius of the critical nuclei of KDP and DKDP crystals were calculated in terms of the classical nucleation theory. In the presence of alcoholic additives, the effect of additives on nucleation of KDP and DKDP crystals growth solutions are discussed.

Kinetics of isotopic exchange of sodium ions in hydrous manganese dioxide from mixed solvent solutions

The Na + capacity of cryptomelane type-hydrous manganese dioxide in aqueous, methanolic and propan-1-olic solutions was determined using two different methods. The Na + capacity decreases reprogressively with alcohol. This pointed to an imbibition of alcohols by the solid. Self-diffusion coefficients (D¯) of sodium ions in manganese dioxide have been determined in aqueous and alcoholic (methanolic and propan-1-olic) solutions by using Paterson's approximation equation. These coefficients (D¯) generally increase with alcohol concentration. The effect of alcohol addition on ion-solvent interactions is counteracted by the effect of ion-ion interactions in the exchanger, leading to an increase of (D¯). Also, adding NaCl to the external aqueous or alcoholic hydroxide solution enhances Na + diffusivity due to a weaker interaction with Cl − coions inside the oxide pores, or it may be that the addition of NaCl decreases the imbibition of alcohol by the oxide.

Alcohol Effect on Equilibrium Constants and Dissociation Dynamics of Xanthone−Cyclodextrin Complexes

The effect of alcohol addition on the ground state complexation of xanthone with cyclodextrins (CDs) and on the dissociation rate constants of triplet xanthone from these complexes was studied by fluorescence and laser flash photolysis experiments. In the case of β- and Hp-β-CD, the addition of alcohol led to the formation of weaker ternary complexes when compared to the xanthone CD binary complexes. In contrast, for γ-CD a slight increase of the complexation strength was observed for the ternary complexes. Addition of alcohols decreased the dissociation rate constant of triplet xanthone from β- and γ-CD by at least a factor of 5. The fact that the dissociation processes was slowed down for both CDs suggests that the effect of ternary complexation agents on the dynamics of complexation was not related to the strength of the ternary complexes formed.

Self-diffusion of sodium ions in hydrous stannic oxide from mixed-solvent solutions

Self-diffusion coefficients of Na +, D ̄ i , inside hydrous stannic oxide have been measured in aqueous and alcoholic solutions at different Na +-capacities. D ̄ i always displays the usual decrease with capacity, which seems to be much less profound at the relatively high capacities. There is apparently almost no effect of addition of methanol on D ̄ i , whereas a decrease of D ̄ i , which disappears towards relatively high capacities, occurs on addition of propan-1-ol. These results are in marked difference with previous results of the effective diffusion coefficients of Na + H + systems. This difference seems to indicate that the effect of alcohol addition in increasing the strength of electrostatic interaction of counter ions with the exchanger surface (a factor which, when predominating, decreases mobility) is higher with protons than with the Na + ions.

Effects of Alcohol Addition on the Pyrolysis of Titanium Tetraisopropoxide and Formation of Titania Particles.

Generation of titania particles by thermal decomposition of a mixture of titanium tetraisopropoxide (TTIP) and tert-butanol was carried out in an aerosol reactor. The reactor wall was initially coated with titania which catalyzes the thermal decomposition of TTIP and tert-butanol. tert-Butanol was added to alter the kinetics of TTIP decomposition and to control particle size. Both the conversion of TTIP and the mean size of titania particles decreased with increasing fraction of tert-butanol in the mixture. The conversion of TTIP was varied from 0.75 to 0.95 and the mean size of the titania particles produced ranged between 40 and 80 nm depending on the input TTIP mole concentration and mole fraction of tert-butanol.When only tert-butanol was decomposed in a titania-coated reactor, the decomposition rate was faster than pure TTIP. In the case of isopropanol, however, the decomposition rate was comparable to that of TTIP and it did not affect the apparent reaction rate of TTIP. We concluded that the competition between TTIP and tert-butanol on the titania surface altered the conversion process and the particle size. The experimental results demonstrate that we can control the particle size with high precision by making two reactants compete in the course of reactions in an aerosol reactor.