Series Of Aliphatic Alcohols Research Articles

Multigram two-step synthesis of difluoromethyl ethers from aliphatic alcohols and glycols

A convenient method for synthesis of alkyl(difluoromethyl)ethers, including subsequent stages of chlorination and fluorination of the O-formyl derivatives was investigated on series of aliphatic alcohols and glycols. Primary and secondary alcohols are converted to the corresponding O-difluoromethyl derivatives in high yield, polydifluoromethyl derivatives of 1,3-propyleneglycol, diethyleneglycole and pentaerythritol can only be successfully obtained with this procedure.

Modification of FCC slurry oil and deoiled asphalt for making high-grade paving asphalt

With the rapid development of modern industry, high-grade paving asphalt is massively required to meet the demands for modern transportation. As one of additives, natural asphalt is indispensable since it can improve the performance of paving asphalt in all aspects. However, the application of non-renewable natural asphalt is increasingly restricted by its limited reserves. It is imperative to find alternative approaches to produce high-grade paving asphalt. Fluid catalytic cracking (FCC) slurry oil is an ideal soft component for producing paving asphalt due to its high content of aromatics and resins. However, its bad ageing resistance limits its application to only low-grade paving asphalt. In the present work, a novel approach for producing high-grade paving asphalt was investigated using chemically modified FCC slurry oil and deoiled asphalt (DOA). The FT-IR and NMR results showed that dehydrogenation and condensation reaction occurred during the ageing process. From a series of aliphatic alcohols and aldehydes, propanal was selected as a proper modifier to improve the ageing resistance of FCC slurry oil. The propanal-modified slurry oil possessed more substituted aromatic units and less aromatic hydrogen atoms than other modified slurry oils, thus showing better ageing resistance. With the increase of length of aliphatic chains in modifier, the modified slurry oil contained more and longer alkyl substituent group on aromatics. Compared with the cross-linked oil (slurry oil modified by cross-linking agent), modified slurry oil possessed similar ageing resistance but higher flowing ability. Also, the effect of operation conditions on the kinematic viscosity of modified slurry oil were investigated. Blended with modified slurry oil, the penetration ratio of asphalt product increased from 53.7 to 66.2, which met the standard of 70# paving asphalt. Both the microscopic observations and FT-IR results indicated that modification process effectively reduced the oxidation degree of asphalt product, thus increasing the ageing resistance. Consequently, with aid of this process, high-grade paving asphalt was readily produced from low value oil from downstream products of refinery, instead of the depleting natural asphalt.

Esterification of benzoic acid in a continuous flow microwave reactor

The direct esterification of benzoic acid with a series of aliphatic alcohols was performed in a continuous flow microwave (MW) reactor. In the first stage, the reactivity of the alcohols towards benzoic acid was mapped in a batch MW reactor. Then, the different esterifications were optimized in the continuous reactor. All parameters including the temperature could be controlled.

Effects of large volume injection of aliphatic alcohols as sample diluents on the retention of low hydrophobic solutes in reversed-phase liquid chromatography

Recent studies showed that injection of large volume of hydrophobic solvents used as sample diluents could be applied in reversed-phase liquid chromatography (RP-LC). This study reports a systematic research focused on the influence of a series of aliphatic alcohols (from methanol to 1-octanol) on the retention process in RP-LC, when large volumes of sample are injected on the column. Several model analytes with low hydrophobic character were studied by RP-LC process, for mobile phases containing methanol or acetonitrile as organic modifiers in different proportions with aqueous component. It was found that starting with 1-butanol, the aliphatic alcohols can be used as sample solvents and they can be injected in high volumes, but they may influence the retention factor and peak shape of the dissolved solutes. The dependence of the retention factor of the studied analytes on the injection volume of these alcohols is linear, with a decrease of its value as the sample volume is increased. The retention process in case of injecting up to 200μL of upper alcohols is dependent also on the content of the organic modifier (methanol or acetonitrile) in mobile phase.

Alkoxylation of cellulose nitrates

Reactions of high nitrogen-containing cellulose nitrate with a series of aliphatic alcohols are studied. In the course of physicochemical studies most probable pathways of chemical reaction were established. They include substitution of nitrate groups by alkoxy group, opening of glucopyranose ring with the addition of the fragment of alcohol by the free bonds formed and formation of the carbonyl group, and also saponification of nitrate groups while studying the process in alkaline medium.

ChemInform Abstract: Absolute and Relative Rate Constants for the Reactions of Hydroxyl Radicals and Chlorine Atoms with a Series of Aliphatic Alcohols and Ethers at 298 K

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Mechanisms of inhibition of CaV3.1 T-type calcium current by aliphatic alcohols

Many aliphatic alcohols modulate activity of various ion channels involved in sensory processing and also exhibit anesthetic capacity in vivo. Although the interaction of one such compound, 1-octanol (octanol) with different T-type calcium channels (T-channels) has been described, the mechanisms of current modulation and its functional significance are not well studied. Using patch-clamp technique, we investigated the mechanisms of inhibition of T-currents by a series of aliphatic alcohols in recombinant human Ca(V)3.1 (alpha1G) T-channel isoform expressed in human embryonic kidney (HEK) 293 cells and thalamocortical (TC) relay neurons in brain slices of young rats. Octanol, 1-heptanol (heptanol) and 1-hexanol (hexanol) inhibited the recombinant Ca(V)3.1 currents in concentration-dependent manner yielding IC(50) values of 362 microM, 1063 microM and 3167 microM, respectively. Octanol similarly inhibited native thalamic Ca(V)3.1 T-currents with an IC(50) of 287 microM and diminished burst firing without significant effect on passive membrane properties of these neurons. Inhibitory effect of octanol on T-currents in both native and recombinant cells was accompanied with accelerated macroscopic inactivation kinetics and hyperpolarizing shift in the steady-state inactivation curve. Additionally, octanol induced a depolarizing shift in steady-state activation curves of T-current in TC neurons. Surprisingly, the recovery from fast inactivation at hyperpolarized membrane potentials was accelerated by octanol up 3-fold in native but not recombinant channels. Given the importance of thalamocortical pathways in providing sleep, arousal, and anesthetic states, modulation of thalamic T-currents may at least contribute to the pharmacological effects of aliphatic alcohols.

Stability of sulfated zirconia and the nature of the catalytically active species in the transesterification of triglycerides

Sulfated zirconia (SZ) exhibits remarkable activity for various hydrocarbon reactions under mild conditions and is of interest for biodiesel synthesis. Nevertheless, to date no detailed study has addressed its activity and stability in liquid polar media such as alcohols, although a number of papers have suggested the possibility for some sulfur leaching. This paper presents an investigation into the activity and stability of a commercial SZ catalyst for the liquid-phase transesterification of triglycerides at 120 °C. The kinetics of tricaprylin (TCP) transesterification with a series of aliphatic alcohols (methanol, ethanol, and n-butanol) were investigated at 120 °C and 6.8 atm in a Parr batch reactor. It was found that the catalytic activity for TCP conversion decreased as the number of carbons in the alkyl chain of alcohol increased, most likely as a result of increased steric hindrance. The SZ catalyst exhibited significant activity loss with subsequent reaction cycles. The characterization of used catalysts after their exposure to various alcohols at 120 °C showed that the SO 2− 4 moieties in SZ were permanently removed. The SO 2− 4 species were leached out, most likely as sulfuric acid, which further reacted with alcohols to form monoalkyl and dialkyl sulfate species, as demonstrated by 1H NMR studies. This was in essence the main route for catalyst deactivation. Our findings conclusively demonstrate for the first time that in alcoholic-liquid media at higher temperatures, SZ deactivates by leaching of its active sites, most likely leading to significant homogeneous rather than heterogeneous catalysis.

Guest-Induced Supramolecular Isomerism and Chirality of Brucine Inclusion Crystals with Aliphatic Alcohols: A Hierarchical Interpretation

Abstract Cocrystallization of brucine with a series of aliphatic alcohols was systematically investigated to understand molecular recognition through supramolecular isomerism and chirality. Guest-induced supramolecular isomers of brucine were obtained by cocrystallization and were categorized into three structural types based on the common 21 helical tape-like assemblies. These supramolecular isomers were elucidated from the molecular structures on the basis of qualitative hierarchical structural analysis through supramolecular chirality. Moreover, it was found that the supramolecular isomerization occurred depending on the size of the guest molecules. This dependence was clearly evaluated on the relationship between the volume of the guest molecules and the packing coefficient of the void spaces in the host cavities.

Complexation Thermodynamics of Cucurbit[6]uril with Aliphatic Alcohols, Amines, and Diamines

Using the isothermal calorimetric titration technique, we determined the stability constants (K), reaction enthalpy (ΔH°), and entropy (ΔS°) for complexation of cucurbit[6]uril (CB[6]) with a series of aliphatic alcohols, mono- and diamines, as well as spermidine and spermine, in aqueous solutions of alkali metal chlorides. The K for spermine reached 5.4 × 1010 M− 1 in 0.2 M LiCl, which is the largest amongst the values reported for CB[6]. Propylamine forms the strongest 1:1 complex with CB[6] (K = 21000 M− 1) in 0.1 M Na acetate buffer, which is driven exclusively by entropy. A comparison of K for 1,3-propanediamine versus 1,4-butanediamine reveals an extraordinary >60000-fold enhancement in affinity, which is the largest increment/CH2 ever observed in supramolecular chemistry. The present results in combination with our ESI-MS data reported recently unambiguously demonstrate that CB[6] exists in aqueous solution of alkali metal salts exclusively as a dicationic species, e.g. [CB[6]·2Na]2+.

Reactivity of Aqueous Fe(IV) in Hydride and Hydrogen Atom Transfer Reactions

Oxidation of cyclobutanol by aqueous Fe(IV) generates cyclobutanone in approximately 70% yield. In addition to this two-electron process, a smaller fraction of the reaction takes place by a one-electron process, believed to yield ring-opened products. A series of aliphatic alcohols, aldehydes, and ethers also react in parallel hydrogen atom and hydride transfer reactions, but acetone and acetonitrile react by hydrogen atom transfer only. Precise rate constants for each pathway for a number of substrates were obtained from a combination of detailed kinetics and product studies and kinetic simulations. Solvent kinetic isotope effect for the self-decay of Fe(IV), kH2O/kD2O = 2.8, is consistent with hydrogen atom abstraction from water.

Efficiency of membrane extraction of phenol-4-aminoantipyrine complex with n-alcohols

In this study, the membrane extraction of phenol-4-aminoantipyrine complex with the series of aliphatic alcohols was investigated by monitoring the efficiency of the process. A commercial polysulphone hollow-fiber membrane module was used in all experiments. The effects of feed and extragent stream flow rates, the ratio of feed to extragent volumes, feed concentrations of phenol and 4-aminoantipyrine and ionic strength of the feed on the efficiency of the preconcentration process were investigated. It has been shown that the efficiency of the studied process increases with decreasing the solubility of alcohols in water, but decreases with increasing their viscosity. In the investigated series of alcohols 1-hexanol showed the highest efficiency.

Some examples of pulse radiolysis

In order to demonstrate the versatility of pulse radiolysis, three examples from various fields of physical chemistry are given: (a) the formation and disappearance of a short-lived thallium–silver cluster is described, (b) as a new method to determine the “salting-out” effect, the concentration of nitrous oxide in aqueous solutions of various sodium chloride content is measured kinetically by monitoring the decay of hydrated electrons, and, (c) the rate constants for the reactions of hydroxyl radicals and hydrogen atoms with a series of aliphatic alcohols are determined from the increase in optical absorption in the UV region typical for alcohol radicals.

Relative rate constants for the reactions of hydroxyl radicals and chlorine atoms with a series of aliphatic alcohols

AbstractRate constants for the gas‐phase reactions of hydroxyl radicals and chlorine atoms with a series of alcohols have been determined by using the relative method. The experiments were performed at 295 ± 2 K and at 1 atmospheric pressure. The obtained values of the rate constants in units of 10−12 cm3 molecule−1 s−1 are as follows: Alcohol Rate Constants for OH with Rate Constants for Cl with Propane Cyclohexane Propane Cyclohexane Ethyl alcohol 3.40 ± 0.25 – 103 ± 4 96 ± 7 n‐Propyl alcohol 5.47 ± 0.44 – 153 ± 13 147 ± 11 Isopropyl alcohol 5.31 ± 0.39 – 73.5 ± 3.7 82.7 ± 7.4 n‐Butyl alcohol 8.66 ± 0.66 – 211 ± 11 223 ± 10 Isobutyl alcohol 9.08 ± 0.35 9.59 ± 0.45 182 ± 4 196 ± 11 tert‐Butyl alcohol 1.11 ± 0.07 – 31.5 ± 2.4 34.1 ± 2.5 n‐Pentyl alcohol 12.2 ± 1.0 12.4 ± 0.5 257 ± 25 258 ± 12 Isopentyl alcohol 13.8 ± 0.5 13.2 ± 1.1 237 ± 7 235 ± 9 The above relative rate constants are based on the values (in units of 10−12 cm3 molecule−1 s−1) of k(OH + propane) = 1.08, k(OH + cyclohexane) = 7.22, k(Cl + propane) = 131 and k(Cl + cyclohexane) = 307. The results are compared with previous determinations. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 35: 81–87, 2003

Molecular Recognition of Aliphatic Alcohols and Carboxylic Acid by Chromophoric Cyclodextrins

Molecular recognition behavior of eight cyclodextrin derivatives, i.e. mono(6-pyridinio-6-deoxy)-α-cyclodextrin (1α), mono(6-pyridinio-6-deoxy)-β-cyclodetrin (1β), mono(6-pyridinio-6-deoxy)-γ-cyclodextrin (1γ), mono[6-(p-picolinio)-6-deoxy]-β-cyclodextrin (2β), mono(6-anilino-6-deoxy)-β-cyclodextrin (3β), mono[6-(m-toluidino)-6-deoxy]-β-cyclodextrin (4β), mono[6-O-(8-quinolyl)]-β-cyclodextrin (5β), and novel mono[6-(2-naphthylamino)-6-deoxy]-β-cyclodextrin (6β), with a series of aliphatic alcohols and carboxylic acid has been investigated spectroscopically. Using the appended aromatic group as a spectral probe, spectroflurometric or spectropolarimetric titrations have been performed at 25°C in aqueous phosphate buffer solution (pH 7.20, 0.1 M) to determine the complex stability constants (Ks ) and Gibbs free energy changes (-δG°) for the stoichiometric 1:1 inclusion complexation of cyclodextrin derivatives with the guests. The results obtained demonstrate that the modified cyclodextrins are highly sensitive to the size/shape and hydrophobicity of guest molecules, and particularly 5β gives an excellent molecular selectivity up to 215 for 1-adamantanol/cyclohexanol. The binding ability and selectivity of the modified cyclodextrins (1α, 1β, and 1β-6β) are discussed from the view points of size/shape-fit concept, induced-fit interaction, and the multiple recognition mechanisms.

Molecular Recognition Studies on Supramolecular Systems. 29. Anilino- and m-Toluidino-β-Cyclodextrins: Structural and Conformational Analyses and Molecular Recognition of Aliphatic Alcohols

Mono(6-anilino-6-deoxy)-β-cyclodextrin (1) and mono[6-(m-toluidino)-6-deoxy]-β-cyclodextrin (2) were synthesized and characterized. Circular dichroism and fluorescence spectral studies and fluorescence lifetime measurements have been performed to elucidate the conformations of 1 and 2 in aqueous buffer solution. 1-D and 2-D NMR spectra of 2 have been measured in D2O to deduce its structure and detailed conformation in solution. From the circular dichroism, fluorescence, and NMR spectroscopic studies, it was revealed that the substituents appended to 1 and 2 penetrate into the cyclodextrin cavity forming a stable self-inclusion complex in aqueous solution, and also that the short linkage between the m-toluidino and cyclodextrin moieties makes the cyclodextrin ring of 2 deformed to some extent. The complex stability constants (K S) of 1 and 2 for a series of aliphatic alcohols have been determined by using spectropolarimetric titrations in aqueous phosphate buffer solution (pH 7.20) at 25°C to elucidate the role of introduced substituents and the weak interactions involved in inclusion complexation by the modified cyclodextrins. The results obtained indicate that the van der Waals and hydrophobic interactions mainly contribute to the formation of complexes between the cyclodextrins and aliphatic alcohols, and the inclusion complexation process involves the induced-fit mechanism. Modified β-cyclodextrin 2 can recognize not only the size, shape, and hydrophobicity of the guest molecules, but also chiral guests, affording a moderate enantioselectivity of 1.55 for (+)/(-)-borneol.

Molecular basis of quantitative structure-properties relationships (QSPR): a quantum similarity approach.

Since the dawn of quantitative structure-properties relationships (QSPR), empirical parameters related to structural, electronic and hydrophobic molecular properties have been used as molecular descriptors to determine such relationships. Among all these parameters, Hammett sigma constants and the logarithm of the octanol-water partition coefficient, log P, have been massively employed in QSPR studies. In the present paper, a new molecular descriptor, based on quantum similarity measures (QSM), is proposed as a general substitute of these empirical parameters. This work continues previous analyses related to the use of QSM to QSPR, introducing molecular quantum self-similarity measures (MQS-SM) as a single working parameter in some cases. The use of MQS-SM as a molecular descriptor is first confirmed from the correlation with the aforementioned empirical parameters. The Hammett equation has been examined using MQS-SM for a series of substituted carboxylic acids. Then, for a series of aliphatic alcohols and acetic acid esters, log P values have been correlated with the self-similarity measure between density functions in water and octanol of a given molecule. And finally, some examples and applications of MQS-SM to determine QSAR are presented. In all studied cases MQS-SM appeared to be excellent molecular descriptors usable in general QSPR applications of chemical interest.

Molecular recognition study on a supramolecular system (XV)

The spectrophotometric titrations have been performed at 298.15 K in buffered aqueous solution (pH 7.20) to give the stability constants (logK5) for the supramolecular system formed by mono-[6-(phenylseleno)-6-deoxy]-β-cyclodextrin (2), mono-[6-(p-tolylseleno)-6-deoxy]-β-cyclodextrin (3), mono[6-(o-tolylseleno)-6-deoxy]-β-cyclodextrin (4), mono-[6-(m-tolylseleno)-6-deoxy]-β-cyclodextrin (5) with a series of aliphatic alcohols. The results were compared with the data reported for the parent β-cyclodextrin. The molecular binding ability and selectivity for aliphatic alcohols of modified β-cyclodextrins (2–5) were discussed from the viewpoints of the induced-fit and geometrical complement. The results obtained indicate that the phenylseleno moiety of β-cyclodextrin derivatives (2–5) as a probe for spectrometry can enhance not only the molecular binding ability but also the molecular recognition ability.

Surface Active Substrates Essential in Lipase-Mediated Esterifications in Foams

Foam offers an appropriate surface to perform lipase-mediated reactions. Aqueous foam, a colloidal dispersion of air in water, offers a very high substrate surface to solvent volume ratio for lipases to act. Esterification, an unfavorable reaction in water, could be efficiently done by lipase in aqueous foams made of lipase substrates. Esterification of oleic acid with a homologous series of aliphatic alcohols of varying length showed that surface excess property of both the substrates is essential for ester formation. The direction of lipase reaction is governed by the composition of the reactants in the interface. Similar reactions could be done in water with substrates adsorbed on hydrophobic beads. Foam-based reactions offer a simple, cheaper and environment-friendly method to conduct lipase-mediated reactions.

Effects of phenazepam and aliphatic alcohols on epileptic complex created in the rat brain cortex

Effects of phenazepam and aliphatic alcohols (methanol, ethanol, butanol, and propanol) on associated epileptic complex created in the rat brain cortex by applications of strychnine were studied. Phenazepam considerably suppressed the epileptic foci and their complexes in a dose-dependent manner. A comparison of anticonvulsive effects in a series of aliphatic alcohols methanol-ethanol-propanol-butanol showed that all these substances are potent anticonvulsants. Propanol and butanol reduce epileptic seizures most intensively, but, at the same time, they are most toxic. Application of labelled4C-ethanol showed that anticonvulsive effects strongly correlate with changes in the ethanol concentration in the blood.