Addition Of Different Alcohols Research Articles

SURFACE PROPERTIES AND MICELLIZATION OF SODIUM ALKYLSULPHATES IN THE PRESENCE OF LOW-MOLECULAR ALCOHOLS

The process of micellization of sodium alkyl sulfates (SAS : sodium decyl- (SDS) and dodecylsulfate (SDDS)) of formation in aqueous solution without or with alcohols including propanol-1, propanol-2 and butanol-1 and their adsorption behavior at air-liquid interface were investigated with both the tensiometry and the conductometry at 298 K. The effect of chain length of alcohol on micellar and interfacial properties were discussed. Some parameters including surface excess concentration (Γmax), minimum area per surfactant molecule (Smin) at air-liquid interface, degree of ionization of micelle, and standard free energy of adsorption and micellization, etc. are estimated. It was experimentally established that the introduction of 0.5-1.0 mol/dm3 of alcohols into surfactant solutions contributes to the process of micellar formation of SAS and increases the stability of the micellar phase, as evidenced by the observed synergistic effect on the critical micelle concentration (CMC). The addition of different alcohols changes the values of Γmax, Smin, CMC of SDS and SDDS and induces an increase in degree of ionization (β) of micelle relative to that in pure water. When alcohols are introduced into SDS and SDDS solutions, the degree of ionization of micelles at a constant length of the alkyl radical of surfactant moderately increases with increasing alcohol content in the solution and ranges from 0.50-0.73 and 0.38-0.75, respectively. Also, the effect of alcohol was discussed. The obtained thermodynamic parameters were used to confirm these behaviors of interfacial adsorption or micellization. An increase in chain length of alcohol promotes the micellization process. The CMC values decrease with increasing length of the alkyl radical of alcohols. Propanol-1, compared to propanol-2, somewhat reduces the value of SDS and SDDS CMC to a greater extent. Standard free energy of micellization ∆G0mic, also confirms the micellization behavior. Standard free energy of adsorption (∆G0адс) indicates that an increase in the chain length of alcohol in aqueous solution is favorable to the adsorption of SDS and SDDS at air-liquid interface. A comparison of the values of the standard free energy of adsorption and micelle formation in sodium alkyl sulfates – alcohols – water systems showed that adsorption is the most thermodynamically advantageous process in the studies systems, and the packing of surfactant “molecules” in micelles is less dense, compared to packing in a mixed adsorption layer.

Alcohols assisted in-situ growth of MoS2 membrane on tubular ceramic substrate for nanofiltration

Molybdenum disulfide-based membranes have received wide attention for their excellent performance in chemical separation field. Yet, manipulating the structure of MoS2 membranes still remains an unprecedented challenge. In this work, the tubular MoS2 ceramic membranes were prepared by in-situ hydrothermal method using aqueous solution of thiourea and ammonium molybdate as precursor solution. The structure and morphology of the membranes were manipulated by introducing different alcohols into the precursor solution. The results indicated that the presence of alcohols drove the transformation of MoS2 morphology from nanosheets to spherical aggregates. As the molecular weight of the alcohols decreased, more small-sized molybdenum disulfide spheres were formed on the tubular ceramic substrate, which resulted in the formation of a great number of large transportation channels and promotion of surface area, and thereby improved the permeability of the membrane. Moreover, the addition of different alcohols enhanced the negative charge of the membrane surface, which ensured an effective rejection while enhancing the membrane permeability. The results demonstrate that the membranes prepared in a water-ethanol mixed solvent possess an excellent permeability for water (33.2 L/(m2 h bar)) and methanol (52.2 L/(m2 h bar)), with a rejection of more than 97% for Eriochrome black T, and an excellent pressure resistance as well as long-term running stability under cross-flow filtration. In addition, such membrane exhibited a below 30% rejection for salts, which can be utilized for dye desalination.

Mechanism on micellization of amino sulfonate amphoteric surfactant in aqueous solutions containing different alcohols and its interfacial adsorption

The process of micellization of amphoteric surfactant sodium 3-(N-dodecyl ethylenediamino)-2-hydroxypropyl sulfonate (C12AS) in aqueous solution without or with alcohols including methanol, ethanol, 1-propanol and 1-butanol and their adsorption behavior at air-liquid interface were investigated with both the tensiometry and the conductometry at 298.15 K. The effect of chain length of alcohol on micellar and interfacial properties were discussed. Some parameters including surface excess concentration (Γmax), minimum area per surfactant molecule (Amin) at air-liquid interface, degree of ionization of micelle, Gordon parameters and cohesive energy density of pure or mixed solvent, and standard free energy of adsorption and micellization, etc. are estimated. At the same amount of alcohol in g/L, the addition of different alcohols changes the values of Γmax, Amin and critical micelle concentration (cmc) of C12AS. Also, the effect of alcohol was discussed. The obtained thermodynamic parameters were used to confirm these behaviors of interfacial adsorption or micellization. These behaviors can be explained theoretically by the change in the polarity or cohesive energy of pure or mixed solvents, the surface charge density of micelle, the partition coefficient of alcohol between micellar pseudophase and intermicellar phase, and the conformation of head group of C12AS on adding alcohol. These findings help with understanding self-assembly behavior of C12AS molecule having electronic delocalization structure at air-liquid interface or in bulk phase and the effect of additives on them, and these results can also provide some information for the design of surfactant formulations and their application in many fields.

The significant effects of linear medium chain fatty alcohols on phase behavior of aqueous solution of mixed cationic–anionic surfactant

The effect of 1-hexanol on the phase behavior of aqueous solutions of sodium dodecyl sulfate (SDS) and cetyl trimethyl ammonium bromide (CTAB) has been systematically studied. The phase ranges of vesicle and liquid crystal (LC) can be greatly extended with the addition of 1-hexanol. These specific structures distributed symmetrically on the two sides of the SDS/CTAB equimolar line in the pseudo ternary phase diagram. The aqueous two phase system (ATPS) contained vesicles that would transform into lamellar LC with the change of ratio of SDS/CTAB. The phase behaviors of SDS/CTAB system with addition of different alcohols (C5OH–C8OH) showed similar trends in structural transition except for phase span, demonstrating that the obstruction of electrostatic interaction between surfactant polar heads was affected by the insertion depth of the added alcohols.

A facile template free synthesis of porous carbon nanospheres with high capacitive performance

Porous carbon nanospheres have been widely used in different fields such as electric devices, catalysts, and water treatment. Here we will introduce a template-free process for the preparation of porous carbon nanospheres starting from a direct 3-aminophenol formaldehyde polymerization in a mixed solution. We identify that the addition of different alcohols, particularly ethanol and n -butanol, is able to change the growth habit of the polymer nanospheres and introduce a favorable inner compositional homogeneity for the preparation of porous structure. After the carbonization of the polymer nanospheres, the obtained porous carbon exhibits promising electrochemical performance when used as electrode material in super capacitor.

Ruthenium Phosphine-Pyridone Catalyzed Cross-Coupling of Alcohols To form α-Alkylated Ketones.

An efficient and green route to access diverse functionalized ketones via dehydrogenative-dehydrative cross-coupling of primary and secondary alcohols is demonstrated. Selective and tunable formation of ketones or alcohols is catalyzed by a recently developed proton responsive ruthenium phosphine-pyridone complex. Light alcohols such as ethanol could be used as alkylating agents in this methodology. Moreover, selective tandem double alkylation of isopropanol is achieved by sequential addition of different alcohols.

Enhancement of hydrophilicity of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) membrane using various alcohols as nonsolvent additives

Flat sheet asymmetric polymeric membranes were prepared from homogeneous solution of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) by phase inversion method using N-methyl-2-pyrrolidone (NMP) as solvent and PEG 6000 as pore forming agent. The effects of addition of different alcohols viz. methanol, ethanol, n-propanol, n-butanol and various quantity of methanol in the casting solution on membrane properties were investigated. The morphology and structure of resulting membranes were observed by field emission scanning electron microscope (FESEM). The permeation performances of the membranes were evaluated in terms of pure water flux (PWF), hydraulic permeability and solute rejection capacity. Extent of membrane hydrophilicity was evaluated in terms of porosity, equilibrium water content (EWC) and water contact angle. Solution of bovine serum albumin (BSA) of molecular weight 68,000Da was used to study the permeation performance of prepared membranes using a batch cell of 350mL capacity. Membranes with 5wt.% of methanol showed highest PWF and smallest water contact angle, while membranes containing different alcohols have almost same PWF.

Hydrothermal synthesis and controlled growth of vanadium oxide nanocrystals

0-, 1- and 2-dimensional nanocrystals of different vanadium oxides were synthesized using hydrothermal reaction of commercial bulk monoclinic VO2 and V2O3 precursor, which, depending on reaction conditions, produced nanoparticles, nanoribbons and nanosheets of different vanadium oxides. Addition of acetone was used to direct growth and produce two-dimensional nanosheets, whose aspect ratio depends on acetone-to-precursor concentration, while addition of different alcohols as ligands successfully controlled the nanoribbon size. Variation of pH also changes the product dimensionality, allowing production of nanosheets at pH < 3, nanoribbons at 3 < pH < 7 and, through inhibition of reaction, nanoparticles at high pH. Products of different morphology exhibit systematic increase in unit cell volume with decrease in thickness of nanocrystals. The reaction occurs with VO2+ ion as the primary reactant, requiring only a source of VO2+ ions, and not necessarily crystalline VO2(M), allowing use of other precursors, like VOSO4. Calculations indicate that nanoribbon formation is primarily caused by differences in relative stability of individual crystal planes of VO2. Addition of different amounts of hydrogen peroxide changes the oxidation state of vanadium to produce V3O7 and V2O5, without affecting the product morphology, while use of bulk V2O3 as a precursor leads to the formation of V2O3 nanoribbons, nanoleaves and nanoparticles with similar mechanisms of size and shape control.

Stripping of nonionic surfactants from the coacervate phase of cloud point system for lipase separation by Winsor II microemulsion extraction with the direct addition of alcohols

Extractive microbial fermentation of lipase by Serratia marcescens ECU1010 in cloud point system was previously carried out in the cloud point system. The direct addition of different alcohols, including iso-butanol, 2-phenylethanol and 1-octanol, into the coacervate phase of the clear supernatant of the fermentation broth formed microemulsion, where the nonionic surfactants and lipase were unevenly partitioned between the different phases in the microemulsion system. The polarity of alcohols strongly affected the microemulsion type at room temperature condition. The results indicated that the Winsor II microemulsion, formed by the addition of iso-butanol or 2-phenylethanol as the organic solvent, favored the stripping of the nonionic surfactant into the O m phase, whereas the lipase was left in the excess aqueous phase. However, the Winsor I microemulsion, formed by the addition of 1-octanol as the organic solvent, failed to separate the lipase from the nonionic surfactant in the coacervate phase of cloud point system, because the nonionic surfactant and lipase were partitioned into the W m phase at the same time. Moreover, in the Winsor II microemulsion extraction with 2-phenylethanol as the organic solvent, in which case the protein–surfactant complexes were absent at the interface between the O m phase and the excess aqueous phase, the high lipase recovery (above 80%) and good nonionic surfactant removal were achieved. The effect of nonionic surfactants on lipase activity was also presented.

Molten-globule like partially folded states of human serum albumin induced by fluoro and alkyl alcohols at low pH

Human serum albumin (HSA) exists in a molten-globule like state at low pH (pH 2.0). We studied the effects of trifluoroethanol (TFE) and hexafluoroisopropanol (HFIP) on the acid-denatured state of HSA by far-UV circular dichroism (CD), near-UV CD, tryptophan fluorescence, and 1-anilinonaphthalene-8-sulfonic acid (ANS) binding. At pH 2.0, these alcohols induced the formation of α-helical structure as evident from the increase in mean residue ellipticity (MRE) value at 222 nm. On addition of different alcohols, HSA exhibited a transition from the acid-denatured state to the α-helical state and loss of ANS-binding sites reflected by the decrease in ANS fluorescence at 480 nm. However, the concentration range required to bring about the transition varied greatly among different alcohols. HFIP was found to have highest potential whereas methanol was least effective in inducing the transition. The order of effectiveness of alcohols was shown to be: HFIP > TFE > 2-chloroethanol > tert-butanol > isopropanol > ethanol > methanol as evident from the C m values. The near-UV CD spectra and tryptophan fluorescence showed the differential effects of halogenated alcohols with those of alkanols. A comparison of the m values, showing the dependence of Δ G H on alcohol concentration, suggests that the helix stabilizing potential of different alcohols is due to the additive effect of different constituent groups present whereas remarkably higher potential of HFIP involves some other factor in addition to the contribution of constituent groups.

Investigations into the epoxidation and alcoholysis of oleochemicals for use as lubricants

AbstractMost lubricants and functional fluids worldwide are based on mineral oil. These fluids contain up to 10% of a wide variety of additives for the improvement of their tribological properties. Several of these are still ecologically hazardous.From an environmental point of view, the use of renewable feedstock is of great interest. In Europe rape seed oil is available in substantial amounts and its esters (triglycerides, esters with saturated or partly unsaturated acids) to some extent display better tribological properties than conventional lubricants. The aim of the work which is presented here has been to improve the stability of these types of ester and their derivatives with regard to oxidation and hydrolysis. This can be done by the addition of different carboxylic acids and alcohols, of various complexities, to the double bonds. This paper deals with the indirect addition of different alcohols, such as methanol, isobutanol, and neopentanol, to the double bond of methyl oleate, and the addition of methanol to the double bonds of glycerin trioleate using the corresponding epoxides as intermediates. The reactions were carried out with environmentally friendly heterogeneous catalysts. Several tests, such as for viscosity, oxidation stability, and biodegradability, were carried out to demonstrate the potential of these newly developed fluids for use as lubricants.

Cyclodextrin-Induced Room-Temperature Phosphorescence of 1-Bromo-2-naphthol upon Formation of Ternary Complexes

The inclusion constant for the 1:1 binary complex between 1-bromo-2-naphthol and β-cyclodextrin in aqueous solution was determined by a spectrofluorimetric method. On the basis of MO calculations, a possible structure of this complex was proposed and compared with those formed by two related naphthol derivatives. After the addition of different alcohols (linear, branched, and cyclic) to the 1-bromo-2-naphthol–β-cyclodextrin solution, a significant enhancement of the room-temperature phosphorescence (RTP) was observed. Both the formation constants and stoichiometries of the formed ternary complexes were determined from RTP data with the use of the computational program EPSILON. It was verified that RTP was also induced by adding different apolar liquids (cyclohexane and 1,3-dibromopropane) as the third component instead of alcohols. Of all the examined compounds, cyclohexanol produced both the largest RTP signal and the more stable ternary complex. The RTP calibration graph for 1-bromo-2-naphthol in the presence of both β-cyclodextrin and cyclohexanol was linear for the range of concentrations between 0.6 and 4.0 μg mL−1 with a limit of detection of 0.2 μg mL−1, with a relative standard deviation ( n = 4) of 4%, for 2.2 μg mL−1.

Alcohol-induced conformational transitions in ervatamin C. An alpha-helix to beta-sheet switchover.

Alcohol-induced conformational transitions of erv C, a highly stable cysteine protease, were followed by CD, fluorescence, and activity. At acidic pH, the addition of different alcohols caused two types of conformational transitions. Increasing the concentration of nonfluorinated alkyl alcohols induced a conformational switch from alpha-helix to beta-sheet. Under these conditions, the protein lost its proteolytic activity and tertiary structure. The switch was a sudden one, observed in 50% methanol, 45% ethanol, and 40% propanol. Under similar conditions of pH and concentration, however, glycerol and TFE enhanced the alpha-helicity of the protein. Methanol-induced denaturation was observed to occur in two stages; the first is the beta-sheet state stabilized at low alcohol concentrations, and the other is the beta-sheet state with enhanced ellipticity stabilized at high alcohol concentrations. This beta-sheet conformation can be attained from the native as well as 6 M GuHCl-denatured state by addition of methanol and exhibits properties different from the native or unfolded state. This state shows loss of tertiary structure and activity, enhanced nonnative secondary structure, noncooperative temperature unfolding, and higher stability toward denaturants as compared to the native state, which are characteristic of the molten globule-like state or O-state, and thus this state may be functioning as an intermediate in the folding pathway of erv C.

Addition Chemistry of Rod-Shaped 1,6-Dicyanohexatriyne: Regioselectivity Control by the Remote Cyano Function

The addition of different alcohols, amines, thioalcohols, ethers, cycloalkanes, tin hydride, alkenes or alkadienes to 1,6-dicyano-1,3,5-hexatriyne (1) leads, with a pronounced regioselectivity, to a series of substituted 1-ene-3,5-diynes. The addition of alcohols, amines and thiols proceeds preferentially in a syn mode leading to diastereomers with an E configuration. The reaction with free radicals, on the other hand, proceeds in an anti addition mode. The [4+2] and [2+2] cycloadditions performed with 1 yielded unsaturated six- and four-membered ring adducts, respectively. The cyclobutene derivatives resulting from [2+2] cycloadditions underwent spontanous electrocyclic ring-opening reactions with the formation of butadiene derivatives. Nucleophilic additions to form 1 lead exclusively to products where the donor atom is bound at C-1. All the reactions, except the formation of 19, showed an excellent regioselectivity with respect to the preferred addition to a terminal C≡C triple bond.

Derivatives of saquayamycins A and B. Regio- and diastereoselective addition of alcohols to the L-aculose moiety.

In continuation of our structure-activity investigations on angucycline antibiotics we prepared derivatives of saquayamycins A (1) and B (4) by regio- and diastereoselective nucleophilic addition of different alcohols to the L-aculose moiety. Reversible protection of the 4'-hydroxy group in 1 by silylation allowed a derivatization at both L-aculose moieties without cyclization towards cinerulose B. The in vitro cytotoxic activity remained almost unchanged after variation at the L-aculose moieties whereas a change in the aglycone structure led to a total loss of the biological activity.

Synthesis and reactions of trinitromethyl compounds

Nitroform (trinitromethane) adds readily in a Michael type of addition to α, β-unsaturated compounds such as acrylic acid and its esters, hydroxymethyl vinyl ketone, and nitroethylene. The synthesis of 2-nitro-3-acetoxy-1-propene and its unique reaction with 1,1-dinitroethane and nitroform is described. 4,4,4-Trinitrobutyric acid was converted to 3,3,3-trinitropropyl isocyanate and 3,3,3-trinitropropyl amine hydrochloride. Trinitromethyl carbamates were prepared by the addition of 2,2,2-trinitroethanol to various isocyanates and the addition of different alcohols to 3,3,3-trinitropropyl isocyanate. Trinitromethyl amines were prepared by the Mannich condensation of 2,2,2-trinitroethanol with various primary amines and the reaction of 3,3,3-trinitropropyl amine with nitroalcohols. All of these carbamates and secondary amines were converted to the corresponding N-nitro derivatives. The synthesis of trinitromethyl heterocyclic compounds and 2,2,2-trinitroethyl esters is also reported.