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The phase behaviour and aggregation characteristics of aqueous solution of Triton X-100 in the presence of several 1-alkyl-3-methylimidazolium salts, [C n mim + ]X − and 1-alkylpyridinium salts [C n Py + ]X − , where n is the alkyl chain length (4,6,8.10) and X − is the anion CF 3 SO 3 − and BF 4 − has been explored. The effect of nonpolar alkyl chain length, cation and anion of these ionic liquids was investigated from cloud point (CP), dynamic light scattering (DLS) and small angle neutron scattering (SANS). ILs with longer alkyl chain on cation drastically increased CP and decreased micelle size. The size, hydrophobicity and polarity of anions also showed marked effect on solution behavior of Triton X-100. The results indicate opposite effect on CP and hydrodynamic diameter (D h ) on addition of ionic salts. SANS results demonstrate that added ILs modulated the size of TX-100 micelle, which is further discussed in terms of penetration of cation and anion into TX-100 micelle depending on the nature of alkyl chain attached to the cation/anion and varying size, hydrophobicity, surface activity of anion. [ABSTRACT FROM AUTHOR]

Anti-agglomeration is a promising approach to address hydrate risks in oil and gas flowlines from the deep sea. Salt concentration of the coproduced water with hydrocarbons is known to affect anti-agglomeration. Most studies report improvement in efficiency of anti-agglomeration but some authors report a decrease from salts. In this work, the effect of water cut (ratio of aqueous phase to total liquid) and NaCl concentration on the effectiveness of the cocamidopropyl dimethylamine anti-agglomerant (AA) are investigated in normal octane and methane systems. We also investigate the synergic effect of a cosurfactant (Span 80) in improving the performance of the AA at water cuts of 10%–30%. A likely mechanism of the synergism is suggested: the co-surfactant (Span 80) promotes the dispersion of water droplets in the oil phase and the AA prevents the agglomeration of the hydrate particles. We investigate emulsion formation and the phase behaviour of octane/brine/AA/Span 80 emulsion to shed light on the mechanisms at play. A solid-like fluid which hardly moves under gravity is observed when the normal octane and water/brine and the anti-agglomerant are mixed at a water cut of 95%. The solid-like behaviour which is attributed to flocculation can be remedied by the introduction of alcohols in the solution. There are similarities in emulsion formation and hydrate anti-agglomeration of normal octane and a condensate liquid which was investigated recently and there are also major differences. [ABSTRACT FROM AUTHOR]

Solvent-aided thermal recovery processes have recently gained practical and research interests among other thermal recovery methods due to their reduced environmental footprint and superior energy efficiency. One of the main challenges in design of solvent-based methods is selection of an appropriate solvent that maximizes the bitumen and solvent recoveries. This study attempts to introduce dimethyl ether (DME) as a non-conventional solvent for heavy oil and bitumen recovery. To investigate the performance of the proposed solvent, thermophysical properties of DME/bitumen are studied. Vapour-liquid equilibrium measurements including solubility, density, and viscosity are performed at three temperatures (100, 125, and 150 °C) and pressures up to 6 MPa. The results were compared with propane/bitumen and butane/bitumen systems. All the measured properties fall between propane and butane systems. The solubility and density data were fairly represented using PR-EoS with AARDs of 10.3 and 1.43 %, respectively, and viscosity data were correlated applying the Pederson corresponding state model with an AARD of 10.7 %. The results suggest that DME is a suitable substitute for solvents such as propane and butane in solvent-aided thermal recovery of bitumen from oil sands. [ABSTRACT FROM AUTHOR]

The phase behaviour of carbon dioxide/propargylic alcohols and carbon dioxide/oxetanes mixtures has been investigated using in-situ FTIR microspectrometry that allows us determining the evolution of the concentration of each component in the liquid phase as a function of temperature and pressure. It was at the same time possible to look inside the cell and to visualize the expansion of the liquid phase during the increase of the pressure. The measurements were performed at three different temperatures (40, 70 and 100 °C) for pressures ranging between 0.1 and 15 MPa. Propargylic alcohol (PA), 2-methyl-3-butyn-2-ol (MBOL), 3-butyn-1-ol (BOL) and trimethylene oxide (TMO) were selected as these molecules are used in the synthesis of cyclic or polycarbonates by coupling with CO 2 . Thus, we determined the CO 2 sorption and the concentration of the substrate in the liquid phase. Thanks to these measurements, we established the pressure-composition phase diagram for the liquid phase of these substrate/CO 2 binary mixtures. [ABSTRACT FROM AUTHOR]

Eight homologous series of 2-(or 3-)substituted phenyl 4ʹ-(4″-alkoxy (2ʹ-, or 3″-substituted phenylazo) benzoates (InXY) were prepared in which the suffix ‘X’ refers to the lateral substituent X attached to the terminal benzene ring that carries the alkoxy group, and the suffix ‘Y’ refers to the substituent attached to the other terminal phenyl group. Within each homologous series, the length of the terminal alkoxy group varies from 8 to 16 carbons, while the lateral polar substituents, X and Y, alternatively varies between CH3and F. The mesophase behaviour was investigated by differential scanning calorimetry and identified by polarised optical microscopy. The results were discussed in terms of the polarity and steric effects of the two lateral substituents. Comparative correlations were made to investigate the effect of the second lateral substituent on the mesophase behaviour of the previously investigated mono-laterally substituted analogues. UV–vis spectroscopic study revealed that the compoundsI8XYexhibited two absorption bands: low intense bands at 254–263 and a broad band at 364–376 nm. These bands are attributed to the π–π∗ transition of the phenyl rings and the whole mesogenic portion. [ABSTRACT FROM PUBLISHER]

The calorimetric results of heat of dilution of SDS aqueous solution [0.0348 mol kg − 1 ] in water and DDAB vesicle solution [0.002 mol kg − 1 ] were applied to estimate the enthalpies of interactions between an anionic surfactant SDS and vesicles formed by DDAB in aqueous solutions at 25 °C and 40 °C. They are negative in the whole investigated SDS concentration range at both temperatures. The enthalpy of interaction changes illustrates the difference between the SDS monomers energetic state in water and that in the DDAB vesicle bilayers. The plots of interaction enthalpy against SDS concentration have completely different shapes at both temperatures. These have been discussed in terms of electrostatic interactions between: positively charged lipid head groups with oppositely charged SDS molecules, which penetrate the vesicular bilayers. It appeared that dependence of interaction enthalpy on SDS concentration can be used to reveal the phase transitions from a liquid crystal to gel state in vesicular system bilayers. Adding SDS to DDAB vesicle solution affects significantly, electrostatic interactions of vesicular bilayers leading to changes of aggregates structural features that have been confirmed by transmission electron microscope examinations. [ABSTRACT FROM AUTHOR]

In this work, three ionic liquids (ILs) from the bio-compatible family of choline cations attached to anions of varying hydrophobicity namely: choline acetate (ChOAc), choline bistriflamide (ChNtf 2 ), and choline chloride (ChCl), have been tested for their gas hydrate inhibition properties for methane and a multi-component Qatari natural gas type mixture (QNG-S1). A rocking-rig assembly (RC-5) has been used to obtain the pressure-temperature (P-T) loops for the studied systems in absence/presence of inhibitors. Two concentrations of 1 and 5 wt% for the choline IL-inhibitors have been chosen which shows distinct effectiveness towards studied single and multi-component hydrate systems. Hydrate suppression temperatures (ΔT) have been calculated from the obtained dissociation data for quantitative analysis of inhibition effect of ILs and its trends against pressure dependence were discussed. Further, to understand the mechanism of hydrate formation and dissociation, the imaging of a complete P-T loop for CH 4 + 5 wt% ChNtf 2 system has been performed using a borescope camera attached to gas hydrate autoclave (GHA) apparatus. Furthermore, the main features of the interaction mechanism between selected ionic liquids and hydrate structures were elucidated at the molecular level through quantum chemical calculations by using density functional theory (DFT) methods. The results on the effectiveness of bio-compatible ILs as hydrate inhibitors compared to their conventional counterparts have been proposed in the manuscript. [ABSTRACT FROM AUTHOR]

The systems chosen for the present investigation,p-n-alkylbenzoic acid (nBAC;n= 6, 7) exhibits nematic-isotropic transition. A comparative study based on quantum probabilistic and statistical thermodynamics has been carried out with respect to translational and orientational motions. The evaluation of net atomic charges and dipole moment at each atomic centre has been carried out through the complete neglect differential overlap (CNDO/2) method. The modified Rayleigh-Schrodinger perturbation theory along with multicentered-multipole expansion method has been employed to evaluate the long-range intermolecular interactions, while the ‘6-exp’ potential function has been assumed for short-range interactions. The total interaction energy values obtained through these computations have been used as input to calculate the probability of occurrence of a particular configuration using the Maxwell-Boltzmann formula. Further, thermodynamic parameters such as Helmholtz free energy, and entropy at room temperature (300 K), and nematic-isotropic transition temperatures have been computed. An attempt has been made to understand the structure-phase behaviour relationship at molecular level. [ABSTRACT FROM PUBLISHER]

Main-chain biodegradable liquid crystal based on c diosgenyl end-capped poly(trimethylene carbonate) [Dios-(TMC)n] was investigated. The novel liquid crystal was synthesized through ring-opening polymerization of trimethylene carbonate initiated by diosgenin, without adding any catalyst. The chemical structure of resulting polymers was confirmed by1H NMR. The liquid crystalline properties were validated by X-ray diffraction, differential scanning calorimetry, and polarising optical microscopy. The results showed that the synthesized Dios-(TMC)n exhibited liquid crystallinity in particular temperature ranges because of the incorporation of the diosgenin moieties. [ABSTRACT FROM PUBLISHER]

A new side cholesterol-functionalised liquid crystal (LC) copolymer based on aliphatic polycarbonate backbone was synthesised. The chemical structures of the block copolymers obtained in this study were characterised with Fourier Transform Infrared Spectroscopy (FT-IR) and Proton Nuclear Magnetic Resonance (1H NMR) spectra. Their thermal stability and phase behaviours were investigated with thermogravimetric analysis (TGA) measurements, differential scanning calorimetry, and polarising optical microscopy. The molecular organisation in the mesophase was studied by temperature-dependent X-ray diffraction (XRD). As a result, the block copolymer bearing side cholesteryl groups showed a glass transition at 15.8°C and a smectic A (SmA) to isotropic phase transition at 151.3°C on heating cycle. XRD indicated that the block LC copolymer showed an interdigitated molecular arrangement of the mesogenic units within the smectic layers. This partial bilayer structure was similar to the SmA phase formed by polar mesogens. [ABSTRACT FROM AUTHOR]

Novel kinds of polymerised ionic liquid crystals (PILCs) bearing imidazolium and bipyridinium groups were synthesised and characterised in this work. Some bromo-polyesters were synthesised in an esterification chain reaction using 2,3-dibromosuccinyl dichloride, isophthaloyl chloride and 4,4′-biphenol. The polyester imidazolium bromides (PIBs) and polyester dipyridinium bromides (PDBs) were obtained by a quaternisation reaction between the bromo-polyesters,N-methylimidazole and 4-4′-bipyridine, respectively. The polyester imidazolium tetrafluoroborates (PITs) and polyester dipyridinium tetrafluoroborates (PDTs) were synthesised using the corresponding PIBs and PDBs in an anion-exchange reaction. The chemical structures, liquid crystalline properties and molecular weights of these polymers were characterised by multiple experimental techniques. All the PILCs including PIBs, PDBs, PITs and PDTs display smectic A phase on heating and cooling cycles. The liquid-crystalline properties of bromo-polyesters are influenced by the length of flexible spacer and composition of polyester backbones, while those of PILCs are determined by the ionic groups as additional important influent factors. In comparison with those of the mother bromo-polyesters, thed-spacing of PILCs reduced slightly due to Im+–Br−, Dp+–Br−, Im+–BF4−and Dp+–BF4−ion pairs in the polymer systems. Monocationic imidazolium salts display weaker interionic and intermolecular interaction, higher mobility and lower viscosity than dicationic dipyridinium salts. [ABSTRACT FROM PUBLISHER]

ABSTRACT To know the possibility of using Indian butter tree seed waste (mahua seed cake [MSC]) as a filler in the production of value-added product such as polyurethane (PU) green composites, a series of PU composites have been fabricated with varying amounts, namely, 0, 2.5, 5.0, 7.5, and 10 wt%, of MSC, and their effects on the physicomechanical properties such as density, surface hardness, tensile strength, tensile modulus, and percentage elongation at break have been studied. It was found that the tensile strength of the green composites increased from 5.61 to 9.5 MPa and tensile modulus increased from 4.75 to 6.07 MPa with an increase in filler content from 2.5 to 7.5 wt%. The fabricated PU/MSC composites were characterized for structural behavior by Fourier transform infrared spectroscopy and for morphological behaviors by scanning electron microscopy. The chemical resistance of the green composites in different chemical environments has been investigated. The thermal stability and thermal degradation behaviors of composites were performed using thermogravimetric analysis. The microcrystalline parameters such as crystallite size (< N>) and lattice strain ( g, %) have been computed using wide-angle X-ray scattering data. Based on these parameters, the structure-property relationship of the PU/MSC green composites has been established. [ABSTRACT FROM AUTHOR]

The production of heavy oil and bitumen is more complex and expensive than conventional oils. One of the main reasons is that heavy oils and bitumen have high viscosity and are usually immobile at the reservoir conditions. The viscosity of heavy oil or bitumen must be lowered in order to be recoverable by an oil recovery method such as solvent injection, steam-assisted gravity drainage (SAGD), and expanding solvent SAGD (ES-SAGD). In this study we report thermo-physical properties of CO 2 and N 2 /bitumen mixtures. Solubility of non-condensable gaseous solvents, i.e. carbon dioxide and nitrogen, in Athabasca bitumen, as well as the liquid phase density and viscosity of solvent saturated bitumen are measured at temperatures up to 190 °C and pressures up to 8 MPa. Moreover, Peng-Robinson equation of state (PR-EoS) is applied to represent the experimental solubility which shows the absolute average relative deviation (AARD) of 4.3% and 7.6% for CO 2 and N 2 , respectively. These findings will find many applications in the design and simulation of heavy oil and bitumen recovery processes. [ABSTRACT FROM AUTHOR]

Carbon capture and storage (CCS) is nowadays considered as one of the most promising methods to counterbalance the CO 2 emissions from the combustion of fossil fuels, natural gas processing, cement manufacturing, etc. In dealing with the transport and the storage of CO 2 -rich streams, design of a safe and optimum process requires the knowledge of thermophysical properties (especially density) of CO 2 -rich mixtures. Consequently, the development of accurate thermodynamic models to evaluate these properties plays a key role in the context of CCS. This work is focused on comparing the capability of four Equations of State (EoSs) in modelling the Vapour-Liquid Equilibrium (VLE) and the density of binary mixtures of interest in the field of CCS. Two Cubic EoSs (CEoS), the original Soave-Redlich-Kwong (SRK) and Peng-Robinson (PR) EoSs, and two Statistical Associating Fluid Theory-based EoSs, namely the Perturbed Chain (PC-SAFT) EoS and the Variable Range SAFT-VR Mie EoS have been considered. These EoSs were compared (with both zero and regressed binary interaction parameters) with respect to VLE and density data of 108 binary mixtures of five main gaseous components (CO 2 , CH 4 , C 2 H 6 , N 2 , and H 2 S). Concerning the cubic EoS, the Peneloux volume translation was used to better correlate densities. The comparison reveals that on average the most accurate VLE and density predictions are obtained with the SAFT-based EoSs, while similar results in VLE calculations are obtained with the four EoSs when regressed binary interaction parameters are used. The SAFT-VR Mie EoS is on average more accurate for the description of VLE and density data than the other studied models. [ABSTRACT FROM AUTHOR]

The design of CO 2 injection wells differs from that of gas and water injectors owing to the effects of the CO 2 phase behaviour. Each CO 2 injection well requires a design specific to the reservoir conditions, rates and injection stream characteristics just as there is no one well design that fits all hydrocarbon production requirements but there are key themes that emerge from our experience in the design of Carbon Capture and Storage (CCS) wells. In depleted reservoirs, the CO 2 injection poses unique challenges when compared to injection for Enhanced Oil Recovery projects or aquifer injection. The potential to generate low temperatures due to CO 2 expansion into vapour phase during steady state injection can be a concern. Here one technique is to employ a “reverse velocity string” that is to deploy slim tubing to create back pressure that avoid the production of low temperature during normal injection conditions. Well operations or transient effects can also generate low temperatures, albeit of short duration. During the highly unlikely event of loss of containment leading to flow to atmospheric conditions, there could be a rapid expansion of CO 2 in the top part of the well. Such an expansion would be accompanied by a reduction in the temperature due to the Joule Thomson effect as the CO 2 travels down the saturation and possibly the sublimation line. This cooling potential is one driver for technological advancement of present day well components. Once the flow is identified, the emergency shutdown system of the well automatically activates (for example closing the tree valves and/or the Subsurface Safety Valve – SSSV). Modelling has been conducted to understand the limitations of the current safety critical equipment for different scenarios. The result of modelling indicates that even in low magnitude releases, the SSSV can be subjected to low temperatures with metal temperatures close to the triple point even when set deep in the well. In addition to the normal requirements of the well equipment in terms of pressure, loads and chemical interactions of the injection fluid; this cooling effect of the CO 2 has an impact on the well design. Existing well equipment, including safety critical components (tree valves and SSSV), have limitations in terms of material embrittlement, qualification envelopes and performance of fluids (annuli and power fluids) at this low temperature. The placement of some well components, such as SSSV, also may be affected by the cooling effect, to ensure its ability to close in case of a release. It is crucial to make a distinction between functionality and integrity requirements, whereby components retain integrity under this low temperature excursion even though they might lose operability. This differentiation has to be identified and agreed at an early stage in the well design. Another critical distinction is between the system and component design rating as some components of the system might be exposed to low temperature subject to placement in the well. An area of well design for the lifecycle of the well that requires significant research and development into is around well intervention, both planned routine intervention with wireline and unplanned remedial intervention via platform and/or vessel. Again here the CO 2 phase behaviour can pose challenges to current equipment and methods. This paper aims to highlight the effects of CO 2 phase behaviour on well design and the considerations for a robust and optimised well design for CCS. [ABSTRACT FROM AUTHOR]

Main-chain biodegradable liquid crystal derived from cholesteryl derivative end-capped poly(trimethylene carbonate) was investigated. The novel liquid crystal was synthesised via ring-opening polymerisation of trimethylene carbonate initiated by cholesteryl derivative with an alkyl spacer and end primary hydroxyl group, without any catalyst. The chemical structure of resulting polymers was verified by1H NMR. Liquid crystalline properties were validated by X-ray diffraction, differential scanning calorimetry, and polarising optical microscopy. The results showed that all the synthesised polymers Chol-(CH2)2-(TMC)nexhibited mesomorphism in particular temperature ranges because of the introduction of the cholesteryl derivative moiety. [ABSTRACT FROM AUTHOR]

Main-chain biodegradable liquid crystal (LC) based on cholesteryl end-capped polycarbonate copolymers was investigated. The novel LC was synthesised through ring-opening copolymerisation of trimethylene carbonate with ε-caprolactone (CL) initiated by cholesterol, without adding any catalyst. The chemical structure of the resulting polymers was confirmed by1H NMR. The liquid crystalline properties were validated by X-ray diffraction, differential scanning calorimetry and polarising optical microscopy. The results showed that the synthesised polycarbonate copolymers Chol-(TMCL)x + y exhibited liquid crystallinity in particular temperature ranges because of the incorporation of the cholesterol moieties. Furthermore, the effect of CL content on the mesomorphism properties of Chol-(TMCL)x+ywas also investigated; the higher the CL content, the lower the mesomorphism properties. It might be attributed to the hindered orientation of LC caused by the crystallinity of the poly(ε-caprolactone) (PCL) segments in the polymer chain. [ABSTRACT FROM AUTHOR]

The preparation, stability and phase behaviour of oil-in-water emulsions formed by dodecane and water and stabilised by naturally amphiphilic, chemically unmodified cellulose nanofibrils (CNF), TEMPO-oxidized cellulose nanofibrils (T-CNF) and cellulose nanocrystals (CNC) were investigated. The stability towards prolonged storage, high temperature (maximum 85 °C), shear and dilution with water was evaluated. Droplet size distributions were determined from micrographs and by NMR diffusion measurements. Oil-in-water Pickering emulsions were formed at all stabiliser and O/W ratios (20–35% oil, 0.1–1.5% nanocellulose) for all three nanocellulosic materials, without the use of any additives. All emulsions creamed rapidly; the creaming layers remained stable for at least one month. The volume of creaming layers formed by CNF and T-CNF are larger and the stability towards coalescence, low shear and high temperature of CNF and T-CNF are higher than the corresponding properties of emulsions stabilised with CNC. This is probably due to the networks formed by the longer fibrils. T-CNF forms a dilute stable emulsion in equilibrium with the creaming layer. No emulsion droplets were visible in the water phases in equilibrium with the creaming layers formed by emulsions stabilised by CNC or CNF. The stability of the dilute T-CNF emulsions is probably due to the ionic charge of the nanofibrils, which is higher than that of the CNF or CNC. It seems that nanocellulosic materials primarily act as stabilisers against coalescence rather than flocculation. [ABSTRACT FROM AUTHOR]

For the search of effective microemulsion systems with the properties demanded for various applications the knowledge of structural properties of the reverse microemulsions for various compositions and temperatures is of high value. In the present study, the microstructure and diffusion of the components of water-in- n -decane Winsor IV microemulsions stabilized by a mixture of nonionic surfactants Span 80 (sorbitane monooleate, HLB 4.9) and Tween 80 (polyoxyethylene sorbitan monooleate, HLB 15.0) at the weight ratios 49:51 (i.e. at the maximal ability to solubilize water) were investigated by viscosimetry, PGSTE NMR and DLS. The system phase diagram obtained at 298.2 K includes the intermediate heterogeneous region between the reverse micelles region and the microemulsions. The water-to-surfactant molar ratio was changed up to 15.5 (13 wt.% of water) at the weight ratios n -decane: surfactants 65:35 and 85:15. The microemulsion droplets are spherical (that is corresponded also to the cryo-TEM data) and grow with the increase of water content. The temperature effect on the aggregates diffusion (and on the aggregates size) in the range 298.2–318.2 K is not pronounced. The bimodal distributions of the diffusion coefficients determined using both DLS and PGSTE NMR methods are specific for the system. The slower diffusion mode relates to the diffusion of mixed microemulsion droplets with the radii Rh ∼10–20 nm. The second stable form of nanoaggregates are “dry” micelles with Rh ∼ 1–2 nm. The data on the diffusion coefficients are of special interest in particular for the molecular dynamic simulation of the reverse micelles or of the microemulsion droplets. [ABSTRACT FROM AUTHOR]

In the supercritical CO2 method of extraction of palm oil, many processes in conventional method, such as degumming, deodorization, refining and bleaching processes, are eliminated. The supercritical method allows palm oil to be extracted and fractionated simultaneously, which not only reduces the cost of processing, but also provides a more environmental-friendly processing alternative. In this research, the high-pressure phase behaviour of the binary system between supercritical carbon dioxide (SC–CO2) and palm oil fatty acid components were investigated. The phase transition is observed from a camera which is connected to a high-pressure variable-volume view cell. Carbon dioxide has high solvating power, nontoxic, inflammable and low critical points. The determination of phase behaviour could offer an insight to the right operating condition of palm oil supercritical fluid carbon dioxide extraction process in order to acquire the desired extraction selectivity and an optimum yield. The phase boundaries of some fatty acids components, lauric acid (C12), stearic acid (C18), and oleic acid (C18) in compressed supercritical carbon dioxide were determined at temperatures of 313.15 K, 323.15 K, 333.15 K, 343.15 K and 353.15 K under pressures between 10 MPa and 60 MPa.

The solubility of CO2 in the non-volatile compounds of n-Hexadecane,Diphenylmetnane, Diphenyl ethane, Ethyl benzene and of Nitrogen in n-Hexadecane, at temperature range 298.15-358.15 K are measured at partialpressure of one atmosphere, Falling-film flow technique was used in the presentexperimental work.It is seen that in most cases the solubility is decreased at the temperatureincreased, though in the case of the Nitrogen/n-Hexadecane system the reverse istrue. The effect is probably related to the decrease in solvent density which occursas the temperature raises. For systems of low Solubility ,this effect tends to counterbalance the increase tendency for solute molecules to "escape" from the solvent,arising from their increase kinetic energy . In addition ,the binary interactionconstant (LAB) was calculated by fitting the mole fraction solubility of solute gasesCO2 and N2 by using Redlich-Kwong equation of state for predicting phase data.The interaction constant LAB was calculated from the following expression:= 1− ( )−0.5 ...........(1) AB AB A B L a a a

Azobenzene liquid crystalline (ALC) ligand contains a cholesteryl group linked to an azobenzene moiety through a carbonyl dioxy spacer (C7) and terminated with an amine group as a polar head. The phase behaviour of the C7 ALC ligand at the air-water (A-W) interface is investigated employing surface manometry. The surface pressure-area per molecule isotherm shows that C7 ALC ligand exhibit two different phases following the phase sequence viz., liquid expanded (LE 1 and LE 2) and then collapse to three-dimensional crystallites. Further, our investigations under different pH conditions and in the presence of DNA reveal the following. Compared to the bulk, the acid dissociation constant (pK a) of an individual amine reduces to 5 at the interfaces. For pH (3.5) < pK a , the protonation of amine groups of C7 ALC ligand facilitates the condensation of the film and enhances the stability. For pH values > pK a , the phase behaviour of the ligand remains the same due to the partial dissociation of the amine groups. The presence of DNA in the sub-phase result in the expansion of isotherm to the higher area per molecule and the compressional modulus extracted reveals the phase sequence; liquid expanded, liquid condensed, followed by a collapse. Further, the kinetics of adsorption of DNA to the amine groups of the ligand is investigated, suggesting the interactions are influenced by surface pressure corresponding to different phases and pH of the sub-phase. Brewster angle microscope studies are carried out at different surface densities of the ligand as well as in the presence of DNA also supports this inference. Atomic force microscope is employed to acquire the surface topography and height profile of C7 ALC ligand (1 layer) after transferring on onto a silicon substrate using Langmuir Blodgett deposition. The difference in the surface topography and thickness of the film indicates the adsorption of DNA onto the amine groups of the ligand. The characteristic UV–visible absorption bands of the ligand films (10 layers) at the air-solid interface are tracked and the hypsochromic shift of these bands is also attributed to these DNA interactions. [Display omitted] • Phase behaviour of C7 azobenzene liquid crystalline (ALC) ligand at the air-water interface is investigated. • Surface manometry studies reveal the condensation of the ligand due to the protonation of amine groups for pH

The aim of this article is to review past progress on experimental and modelling developments for depressurisation, release and dispersion of CO2 from high-pressurised pipelines. For the experimental work, several data were analysed from big projects (COOLTRANS, CO2PipeHaz, CO2PIPETRANS and COSHER) to understand release behaviours of high-pressure CO2 and to validate models developed for assessment of safety distances of CO2 pipelines. For the modelling development, mathematical and numerical models were applied to predict the thermo- and fluid-dynamical behaviours of CO2 in a broken pipeline and in a near field, and the dispersing cloud of CO2 in a far field. It was found that homogeneous relaxation model has given better predictions of the CO2 depressurisation and release than homogeneous equilibrium model. It was also found that Peng-Robinson and three-phase accurate equations of state could accurately predict the thermodynamic behaviours of CO2 in the broken pipeline and in the near field respectively. The Lagrangian particle-tracking method was found to accurately predict the far-field CO2 concentration with the presence of complex terrain. No impacts of toxic impurities (H2S, SO2) on depressurisation, release and dispersion of CO2 mixture was experimentally investigated. Further modification and validation of the novel method proposed for the high-pressure CO2 release from buried pipelines are required to accurately predict the unbalanced flow and the behaviour of solid CO2 in and around the crater. Finally, further laboratory- and large-scale experimental data are required to investigate and support validation of models predicting the impact of the toxic impurities on the CO2-mixture release. [ABSTRACT FROM AUTHOR]

Surfactants have been the basis for applications in several industrial sectors for a long time. However, fundamental research was 50 years ago still limited to a small number of academic groups and even basic aspects were controversial. The field has since undergone an enormous expansion and the improved understanding has laid the basis of numerous new products as well as been the basis of important parts of nano-science and -technology.The present author has during 50 years in academia devoted most of his research to amphiphilic compounds, including both surfactants and polymers. Hereby, I had the privilege of following a very exciting development. In 2015, I had the honour to receive the Life-time Achievement Award of IACIS, the International Association of Colloid and Interface Scientists. IACIS organizes since the 1970s a tri-annual symposium, typically the best attended in the field. For the first time since 2000, it was in 2015 organized in Europe, namely Mainz, Germany. This treatise is based on my award lecture in Mainz, which covered developments from my first research as a new Ph D student in Stockholm to current work as an emeritus and visiting professor. Interestingly, discoveries in my very early work contributed to solving problems in now on-going research. Håkan Wennerström kindly wrote a quite comprehensive paper about my achievements a few years ago (Adv Colloid Interf Sci 205:1-8, [1]). In writing the present paper, I have strived at covering mainly topics not treated in detail by Håkan. In fact, I will emphasize very much our early studies as well as our studies of surfactant self-assembly by NMR and in particular look at the developments of our research and connections between different research topics. [ABSTRACT FROM AUTHOR]

This work explores the n vs. iso isomerization effects on the physicochemical properties of different families of ionic liquids (ILs) with variable aromaticity and ring size. This study comprises the experimental measurements, in a wide temperature range, of the ILs' thermal behaviour, heat capacities, densities, refractive indices, surface tensions, and viscosities. The results here reported show that the presence of the iso -alkyl group leads to an increase of the temperature of the glass transition, T g . The iso- pyrrolidinium (5 atoms ring cation core) and iso -piperidinium (6 atoms ring cation core) ILs present a strong differentiation in the enthalpy and entropy of melting. Non-aromatic ILs have higher molar heat capacities due to the increase of the atomic contribution, whereas it was not found any significant differentiation between the n and iso -alkyl isomers. A small increase of the surface tension was observed for the non-aromatic ILs, which could be related to their higher cohesive energy of the bulk, while the lower surface entropy observed for the iso isomers indicates a structural resemblance between the IL bulk and surface. The significant differentiation between ILs with a 5 and 6 atoms ring cation in the n -alkyl series (where 5 atoms ring cations have higher surface entropy) is an indication of a more efficient arrangement of the non-polar region at the surface in ILs with smaller cation cores. The ILs constituted by non-aromatic piperidinium cation, and iso -alkyl isomers were found to be the most viscous among the studied ILs due to their higher energy barriers for shear stress. [ABSTRACT FROM AUTHOR]

The phase behaviour of microemulsion systems, which are used as reaction media for hydroformulation and Heck coupling reactions, is investigated. A detailed analysis of microemulsion systems is the key for a successful implementation in technical processes. In the case of the hydroformulation reaction, the desired three-phase state is shifted depending on the composition of the reaction mixture and a temperature profile is required to maintain this state during the whole reaction. In case of the Heck coupling reaction, the desired state is an oil-in-water (o/w) one-phase microemulsion. We found that the best reaction performance is with K 2 CO 3 as the base, but at higher reactant concentrations with the same base only two-phase systems are obtained. Heck reaction was successfully performed at higher reactant concentrations in the two-phase system consisting of >75 wt% water. The applied heterogeneous sol–gel supported palladium catalyst could be easily recycled with minor catalyst leaching. [ABSTRACT FROM AUTHOR]

The abrupt change in the zeta potential-pH trend at pH 7 showed that positively charged hydrolysis products of both Mg ( II ) and Ca ( II ) ions are adsorbed on washed positively charged alumina particles. This pH is much lower than that predicted pH from equilibrium data for the formation of these hydrolysis products. Surface induced hydrolysis has been attributed by others as being responsible. The yield stress–pH curve was also shifted to a much higher pH in the presence of Mg ( II ) and Ca ( II ). The maximum yield stress of the washed alumina suspension at pH 9.5 was shifted to pH 12 and 13 by Mg ( II ) and Ca ( II ) additives respectively. The magnitude of the maximum yield stress in the presence of Mg ( II ) and Ca ( II ) appeared to be larger or as large as that without these additives. The species diagrams of Mg ( II ) and Ca ( II ) were used to explain change in the zeta potential and yield stress behaviour with pH. Insoluble Mg ( OH ) 2 and Ca ( OH ) 2 species are the predominant products at the pH of maximum yield stress. Precipitate bridging was invoked to explain the additional attractive force responsible for the larger maximum yield stress. Steric effect will also be present due to the adsorbed layer. The new phenomena observed here are due to the concentration of Mg ( II ) and Ca ( II ) employed, ranging from 0.002 to 0.41 M, being generally more than an order of magnitude larger than that used in previous studies. [ABSTRACT FROM AUTHOR]