Wide Range Of Liquids Research Articles

Robust Organogels from Nitrogen-Containing Derivatives of (R)-12-Hydroxystearic Acid as Gelators: Comparisons with Gels from Stearic Acid Derivatives†

Thirteen members of a new class of low molecular-mass organogelators (LMOGs), amides, and amines based on (R)-12-hydroxystearic acid (HSA; i.e., (R)-12-hydroxyoctadecanoic acid) and the properties of their gels have been investigated by a variety of structural and thermal techniques. The abilities of these LMOGs, molecules with primary and secondary amide and amine groups and the ammonium carbamate salt of 1-aminooctadecan-12-ol, to gelate a wide range of organic liquids have been ascertained. Their gelating efficiencies are compared with those of HSA and the corresponding nitrogen-containing molecules derived from stearic acid (i.e., HSA that lacks a 12-hydroxyl group). Several of the HSA-derived molecules are exceedingly efficient LMOGs, with much less than 1 wt % being necessary to gelate several organic liquids at room temperature. Generally, the self-assembled fibrillar networks of the gels consist of spherulitic objects whose dimensions depend on the protocol employed to cool the precursor sol phases. X-ray studies indicate that the LMOG molecules are packed in lamellae within the fibers that constitute the spherulites. In addition, some of the organogels exhibit unusual thixotropic properties: they recover a large part of their viscoelasticity within seconds of being destroyed by excessive strain shearing. This recovery is at least an order of magnitude faster than for any other organogel with a crystalline fibrillar network reported to date. Correlations of these LMOG structures (as well as with those that lack a hydroxyl group along the n-alkyl chain, a headgroup at its end, or both) with the properties of their gels, coupled with the unusual theological properties of these systems, point to new directions for designing LMOGs and organogels.

Two detergent stable alkaline serine-proteases from Bacillus mojavensis A21: Purification, characterization and potential application as a laundry detergent additive

Two detergent stable alkaline serine-proteases (BM1 and BM2) from Bacillus mojavensis A21 were purified. The molecular weights of BM1 and BM2 enzymes determined by SDS–PAGE were approximately 29,000 Da and 15,500 Da, respectively. The optimum pH values of BM1 and BM2 proteases were shown to be 8.0–10.0 and 10.0, respectively. Both enzymes exhibited maximal activity at 60 °C, using casein as a substrate. The N-terminal amino acid sequences of BM1 and BM2 proteases were AQSVPYGISQIKA and AIPDQAATTLL, respectively. Both proteases showed high stability towards non-ionic surfactants. The enzymes were found to be relatively stable towards oxidizing agents. In addition, both enzymes showed excellent stability and compatibility with a wide range of commercial liquid and solid detergents. These properties and the high activity in high alkaline pH make these proteases an ideal choice for application in detergent formulations.

Equations of State in Soil Compression Based on Statistical Mechanics

ABSTRACT There have been many theories and interpretations of the compression process for soil. However due to the complexity of the compression process for a wide range of soil states, i.e., suspended, liquid, plastic, semisolid or solid states like rock, the interaction between the states or the transition from one state to another, there have often been misunderstandings and difficulties regarding the application of these theories. In this study, an ideal particle distribution in an ideal ground system is derived to find the equation of state, a general compression process for a wide variety of soil types and states. In other words, it is a general relationship between the void ratio and effective overburden pressure in terms of interparticle energy and is thus a “law of soil.” The principle is based on the law of energy distribution in statistical mechanics. The derived equations can be applied to describe the void ratio profile and the compression process of various soils. Case studies show that this theoretical approach agrees well with the experimental data obtained for several soils such as sediments, Mexican City clay, sand and others.

Tailoring supported ionic liquid membranes for the selective separation of transesterification reaction compounds

Ionic liquids are a new class of environmentally friendly solvents which are becoming increasingly important in separation processes because they can be tailored for specific applications by an appropriate choice of their cationic and anionic components. In this work, a wide range of ionic liquids with different cation and anion compositions have been tested as liquid phase in supported liquid membranes for selectively separating the substrates and products of a transesterification reaction, with the aim of better understanding the design rules for producing ionic liquids for this particular application. It was found that selectivity values are mostly dependent on the anion composition of the ionic liquid, the highest value being reached with ionic liquids based on the methylsulfate anion. As regards cation composition, it was observed that higher selectivities were reached with ionic liquids which contain cations with shorter alkyl chain lengths. Furthermore, a relationship was established between the permeability of the compounds and their hydrophilicity which suggests that the capability of a given supported ionic liquid to separate the target compounds can be assessed simply by evaluating the Hildebrand solubility parameter of each compound.

Alkylammonium-Based Protic Ionic Liquids Part I: Preparation and Physicochemical Characterization

Novel alkylammonium-cation-based protic acid ionic liquids (PILs) were prepared through a simple and atom-economic neutralization reaction between an amine, such as diisopropylmethylamine, and diisopropylethylamine, and a Brønsted acid, HX, where X is HCOO-, CH 3COO-, or HF2-. The density, viscosity, acidic scale, electrochemical window, temperature dependency of ionic conductivity, and thermal properties of these PILs were measured and investigated in detail. Results show that protonated alkylammonium such as N-ethyldiisopropyl formate and N-methyldiisopropyl formate are liquid at room temperature and possess very low viscosities, that is, 18 and 24 cP, respectively, at 25 degrees C. An investigation of their thermal properties shows that they present a wide liquid range up to -100 degrees C and a heat thermal stability up to 350 degrees C. Alkylammonium-based PILs have a relatively low cost and low toxicity and show a high ionic conductivity (up a 8 mS cm(-1)) at room temperature. They have wide applicable perspectives for fuel cell devices, thermal transfer fluids, and acid-catalyzed reaction media and catalysts as replacements of conventional inorganic acids.

Evaporation rate of a novel tilted solar liquid desiccant regeneration system

The regeneration system represents a vital part of any desiccant air conditioning system. The need of a solar assisted desiccant regeneration system is more important today. In this paper, an experimental study of a novel regeneration system modified from solar tilted still is carried out. A corrugated blackened surface is used to heat the desiccant and an air flow is used to regenerate calcium chloride solution. The effect of the liquid to air flow rate ratio; the desiccant temperature; the desiccant concentration and the inlet air humidity ratio on the evaporation rate has been studied experimentally. A wide range of liquid to air flow rate ratios are employed. The optimum value of the liquid to air flow rate ratio for higher evaporation rate is reported.

Short communication. An in vitro approach for ecotoxicity testing of toxic and hazardous wastes

In waste-characterization, chemicals with a low acute toxicity but with a high long-term hazard such as PBTs (persistent, bioaccumulable, and toxic chemicals) are difficult to identify, leading to an inaccurate assessment of their risk to the environment. This study assesses the sensitivity of in vitro assays with rainbow trout cell line RTG-2 as a tool for the ecotoxicological testing of hazardous wastes using a battery of bioassays, including a neutral red (NR) assay for predicting cytotoxicity, a Beta-galactosidase (Betagal) assay for predicting cellular defence, and two sub-lethal damage assays: ethoxy resorufin-O-deethylase (EROD) and glutathione S-transferase (GST) to check for induction of cytochrome and for alteration of antioxidant defences respectively. Six samples of complex waste, covering a wide range of liquid (A to C) and solid (1 to 3) matrices were tested. The EC50-values (NR) ranged from 0.09 mL/100 mL (B) to 2.01 mL/100 mL (2). A hormesis effect (Betagal) at low concentrations was observed for the A (0.03-0.18 mL/100 mL), 1 (0.03-0.29 mL/100 mL) and 2 (0.03-0.29 mL/100 mL) samples. A dose-dependent stimulation of enzymatic activity was observed for the B ((EROD (0.58-4.68 mL/100 mL), Betagal (0.58-4.68) and GST (0.14-1.17 mL/100 mL)) and C ((EROD (0.29-4.68 mL/100 mL) and Betagal (2.34-4.68)) samples. No effects were observed at the highest concentration tested (74 mL/100 mL) for sample 3. The in vitro approach can be considered to be an efficient, rapid and cost effective screening system to provide basic information on toxic and hazardous waste for further analysis and risk evaluation.

Influence of temperature on fast-mode cyclic operation hydrodynamics in trickle-bed reactors

Despite the merits of periodic operation praised in the academic literature as one of the process intensification strategies advocated for trickle-bed reactors (TBRs), there is still reluctance to implement it in industrial practice. This can partly be ascribed to the lack of engineering data relevant to the elevated temperature and pressure characterizing industrial processes. Currently, the hydrodynamics of trickle beds under cyclic operation, especially in fast mode at elevated temperature and pressure, remains by and large terra incognita. This study proposes exploration of the hydrodynamic behavior of TBRs experiencing fast liquid flow modulation at elevated temperature and moderate pressure. The effect of temperature and pressure on the liquid holdup and pressure drop time series in terms of pulse breakthrough and decay times, pulse intensity and pulse velocity was examined for a wide range of superficial gas and liquid (base and pulse) velocities for the air–water system. The pulse breakthrough and decay times decreased, whereas the pulse velocity increased with temperature and/or pressure. The pressure drop was attenuated with increasing temperature for a given superficial gas, and base and pulse superficial liquid velocities. Experimental pulse velocity values were compared to the Giakoumakis et al. [2005. Induced pulsing in trickle beds—characteristics and attenuation of pulses. Chemical Engineering Science 60, 5183–5197] correlation which revealed that it could be relied upon at elevated temperature and close to atmospheric pressure.

Taylor cones of ionic liquids from capillary tubes as sources of pure ions: The role of surface tension and electrical conductivity

The emissions of Taylor cones from a wide range of ionic liquids (ILs) have been tested in vacuo in an attempt to identify what physical properties favor the purely ionic regime (PIR). This regime is well known in the case of Taylor cones of liquid metals. For nonmetallic liquids, it has been previously observed in conventional (capillary tube) electrospray sources at room temperature only for the room temperature molten salt (ionic liquid) EMI–BF4 (EMI=1-ethyl-3-methylimidazolium). A large number of other ILs and their mixtures have been studied here, most of which (but not all) are unable to reach the PIR at room temperature. Based on these results and additional theoretical considerations, strong support is assembled for the notion that the PIR is favored by ILs not only of high electrical conductivity but also of high surface tension. This hypothesis is confirmed by tests with three recently synthesized ILs, EMI–GaCl4, EMI–C(CN)3, and EMI–N(CN)2, all of which combine exceptional surface tension and electrical conductivity, and all of which reach the PIR at room temperature far more readily than EMI–BF4.

Modelling of Two-Phase Flow Through Concentric Annuli

A mathematical model is introduced in order to predict the flow characteristics of multiphase flow through an annulus. Flow patterns and frictional pressure losses estimated using the proposed model are compared with the experimental data of a wide range of liquid and gas flow rates recorded at a flow loop consisting of numerous circular pipes and annulus. The results showed that the model predictions for flow patterns and frictional pressure losses are reasonably accurate. Moreover, it is observed that geometry and liquid phase viscosity have a significant influence on flow pattern transitions and frictional pressure losses.

Level sensing of liquids and solids – a review of the technologies

PurposeExamines the wide range of liquid and solid level sensors, their technologies and commercial application.Design/methodology/approachProvides background information on trends in level sensing, on how each type works and the various applications. Some selection criteria are given.FindingsThere is a wide range of level sensors for every target liquid and solid sensing application, but the sector is technologically mature. There are some new application areas deriving from legislation and climate change.Originality/valueProvides information of value for those involved with sensor applications.

Experimental Investigation on Bubble Turbulent Diffusion in a Vertical Large-Diameter Pipe by Wire-Mesh Sensors and Correlation Techniques

Experiments with air-water flows have been carried out in a vertical pipe of ~194-mm diameter and 9-m length, and a wide range of superficial liquid and gas velocities has been covered. At a distance of 7.6 m from the air injection, two wire-mesh sensors are installed, located at a distance of 63.3 mm from each other. The wire-mesh sensors measure sequences of instantaneous two-dimensional gas-fraction distributions in the cross section in which they are mounted, with a spatial resolution of 3 mm and a frequency of 2500 Hz. The spatial cross-correlations of the gas-fraction signals have been evaluated, and on their basis turbulent diffusion coefficients have been estimated.It is found that for a given liquid superficial velocity, a sudden increase of the diffusion coefficient takes place when the superficial gas velocity is increased above a certain value. The abrupt increase of the diffusion coefficient occurs in correspondence of the transition from mono- to bimodal bubble size distributions.The experimental diffusion coefficients are compared with the prediction of the Sato model (experimental gas-fraction profiles and bubble size distributions are given as input). Even though this model has been developed for bubbly flow, the general trends are well captured also in the churn-turbulent regime.

Efficient Heck reactions catalyzed by a highly recyclable palladium(ii) complex of a pyridyl-functionalized imidazolium-based ionic liquid

The reactions of 2-(2-pyridyl)imidazole with alkyl iodides at 25 degrees C in the presence of base gave rise to 1-alkyl-2-(2-pyridyl)imidazole. Subsequent neat reactions with alkyl or polyfluoroalkyl halides at 100 degrees C, followed by anion exchange with LiN(SO(2)CF(3))(2), generated the mono-quaternary ionic liquids. All of them have excellent thermal stability and wide liquid range. Most of the salts with asymmetric N-substituents are liquid at room temperature. The effect of N-substituent variation and symmetry on NMR, TGA and DSC is discussed. Reaction of with palladium(II) chloride produced a mononuclear palladium ionic liquid complex, the structure of which was confirmed by single-crystal X-ray diffraction analysis. The Heck cross-coupling reactions using in ionic liquid demonstrated excellent stability and recyclability.

Ionic liquids via reaction of the zwitterionic 1,3-dimethylimidazolium-2-carboxylate with protic acids. Overcoming synthetic limitations and establishing new halide free protocols for the formation of ILs

The previously reported preparation of 1,3-dimethylimidazolium salts by the reaction of 1,3-dialkylimidazolium-2-carboxylate zwitterions with protic acids has been reinvestigated in detail, leading to the identification of two competing reactions: isomerisation and decarboxylation. The ability to control both pathways allows this methodology to be used as an effective, green, waste-free approach to readily prepare a wide range of ionic liquids in high yields. Additionally, this reaction protocol opens new possibilities in the formation of other imidazolium salts, whose syntheses were previously either very expensive (due to ion exchange protocols involving metals like Ag) or difficult to achieve (due to multiple extractions and large quantities of hard to remove inorganic by-products).

Molecular Organogels. Soft Matter Comprised of Low‐Molecular‐Mass Organic Gelators and Organic Liquids

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Ionic-Liquid-Supported Synthesis: A Novel Liquid-Phase Strategy for Organic Synthesis

Soluble ionic liquids have recently been used as supports for catalyst/reagent immobilization and synthesis in homogeneous solution phase. The wide range of ionic liquid supports available makes their use as supports compatible with most common chemistries. The solubility properties of these ionic liquid supports can be tuned by the variation of cations and anions to make them phase separate from less polar organic solvents and aqueous media. The ionic-liquid-supported species can therefore be purified from the reaction mixture by simple washings. Ionic-liquid-supported catalysts and reagents have been prepared and used, and they are easily recovered and reused. Parallel and combinatorial libraries of small molecules have been synthesized. Ionic-liquid-supported synthesis (ILSS) has been applied to the preparation of oligopeptides and oligosaccharides. The comparison of ILSS with solid-phase synthesis, soluble-polymer-supported synthesis, and fluorous phase synthesis has been highlighted where applicable.

Rapid ascent and contamination of magmas through the thick crust of the CVZ (Andes, Ollagüe region): Evidence from a nearly aphyric high-K andesite with skeletal olivines

Described in this study are the mineralogy and petrology of a nearly aphyric high-K andesite (herein referred to as the SC2 sample) located in the Ollagüe volcano region, characterized by microcrystalline to glassy groundmass and very few olivine and pyroxene microphenocrysts (≪ 3 vol.%). Olivine (Fo 72–82) exhibits a wide range of skeletal crystal morphologies due to the high cooling rate and geometrically-different entrapped inclusions of glass, ranging in composition from intermediate to acid (SiO 2 53–72 wt.%). Plagioclase (An 56–64), meanwhile, often shows a quench texture with holed and swallow-tailed forms. Ferroan enstatite locally occurs as subhedral microphenocrysts whereas ferroan diopsides to magnesium-rich augites are common in the groundmass. Opaque minerals (Ti–Al-magnetites and Cr-spinels) are rare and generally found as tiny euhedral inclusions in the olivines. Although SC2 magma should have contained a relatively high amount of H 2O (ca. 6 wt.%), hydrous minerals such as amphibole were never on the liquidus because a high temperature (≥ 1000 °C) was maintained by the rising magma up to the shallow crustal levels. The SC2 incompatible trace element pattern has a typical arc-like signature with Sr–Nd isotopic ratios falling within the range of the Quaternary volcanic rocks of the CVZ, straddling between the less contaminated basaltic andesites and the more contaminated intermediate to acid extrusives of the Ollagüe volcano. Pb isotopic values of the studied lava also fit very well with the overall volcanic rocks of the Southern CVZ and suggest that the SC2 magma underwent a contamination from the Paleozoic basement inferred to characterize this region of the Andean Cordillera. During decompression, the H 2O-rich mantle-derived magma reached a superheated status (as the aphyric character of the SC2 sample demand) and was contaminated to some extent by high-T, “fertile” crustal wall-rocks. The contamination process of the superheated magma probably occurred at the meso-microscale as a complex function of diffusion rates of components in the magma and gave rise to a wide compositional range of liquids, frozen within the skeletal olivines before complete homogenization. However, this does not necessarily imply the existence of geologically significant batches of magmas with compositions similar to those of the glass inclusions. Neutral to extensional stresses during a Quaternary tectonic phase of crustal relaxation of the Altiplano–Puna Volcanic Complex should have permitted the fast uprising of the SC2 magma through the thick CVZ crust without any storage and differentiation in magma chambers. The observed data indicate that in the Andean CVZ, some mantle-derived magmas, although modified by crustal contamination “en route” to the surface, were able to rise with negligible fractional crystallization, by-passing the flanks of Quaternary stratovolcanoes.

Molecular Organogels. Soft Matter Comprised of Low-Molecular-Mass Organic Gelators and Organic Liquids

This Account presents recent advances in understanding how and why dilute solutions/sols of low-molecular-mass organic gelators (LMOGs) undergo microscopic phase separation to form self-assembled fibrillar networks in molecular organogels. Concepts are illustrated structurally at the subnanometer (molecular) to several millimeter (bulk) length scales and dynamically over time scales that follow the assembly of supersaturated solutions/sols into gel phases. Examples include both structurally complicated (ALSmolecules with aromatic, linking, and steroidal groups) and simple (n-alkanes or n-alkanes along whose chains a hetero-group has been inserted) LMOGs in a wide range of organic liquids.

Investigation of Physicochemical Properties of Lactam-Based Brønsted Acidic Ionic Liquids

Novel lactam-cation-based Brønsted acid ionic liquids (ILs) were prepared through a simple and atom-economic neutralization reaction between a lactam, such as caprolactam and butyrolactam, and a Brønsted acid, HX, where X is BF4-, CF3COO-, phCOO-, ClCH2COO-, NO3-, or H2PO4-. The density, viscosity, acidic scale, electrochemical window, temperature dependency of ionic conductivity, and thermal property of these ILs were measured and investigated in detail. The results show that protonated caprolactam tetrafluoroborate (CPBF) has a relatively strong acidity with -0.22 of Hammett acidic scale H0 and caprolactam trifluoroacetate (CPTFA) and pyrrolidonium trifluoroacetate (PYTFA) ILs possess very low viscosities, that is, 28 cP and 11 cP, respectively. An investigation of thermal property showed that a wide liquid range (up to -90 degrees C), moderate thermal stability (up to 249 degrees C for 10% of decomposition), and complex polymorphism were observed in these ILs. In comparison to imidazolium-cation-based ILs, the lactam-cation-based Brønsted acid ILs have a relatively lower cost, lower toxicity, and comparable ion conductivity and heat storage density (more than 200 MJ/m3). They have wide applicable perspectives for fuel cell devices, thermal transfer fluids, and acid-catalyzed reaction media and catalysts as replacements of conventional inorganic acids.

Highly conducting ionic liquids based on l-ethyl-3-methylimidazolium cation

Highly conducting EMI-based room-temperature (RT) ionic liquids containing transition metals [EMI][M(III)Cl 4] (M = Fe, Fe 0.5Ga 0.5 and Ga) were prepared, and their thermal and physical properties were well investigated, where EMI is l-ethyl-3-methylimidazolium, All the salts are liquid at RT and show a wide liquid range. High ionic conductivities (1.8-2.0x10 −2 S cm −1 at 20 °C) and low viscosities (12–14 cP at 30 °C) are comparable to those of N(CN) 2 and C(CN) 3 salts. The FeCU and Fco.5Gao.5Cl4 melts exhibit a Curie-like behavior arising from the = 5/2 spins on iron(III) ions, indicating the first conductive-paramagnetic biftinctional RT ionic liquids. On cooling, the solidified FeCl 4 salt passes through an antiferromagnetic transition at 4.2 K. On the basis of sixteen EMI-based RT ionic liquids including the present salts, it has become apparent that the conductivity is proportional to the reciprocal of the product of the anion weight and the viscosity.