Phase behavior of CO2-expanded fluorinated microemulsions

The formation of CO2-expanded, fluorinated reverse microemulsions is demonstrated for the system of perfluoropolyether (PFPE) surfactant (ClPFPE-NH4, MW = 632) and PFPE oil (PFPE, MW = 580). The phase behavior of this system is examined as a function of temperature (25-45 degrees C), pressure, CO2 concentration, and water to surfactant molar ratios (W0 = 10 and 20). Visual observations of one-phase behavior consistent with reverse microemulsion formation are further supported by spectroscopic measurements that establish the existence of a bulk water environment within the aqueous core. Microemulsion formation is not observed in the absence of CO2 for this PFPE surfactant/PFPE oil system, and a CO2 content greater than 70 mol % is required to induce microemulsion formation. Over the range of water loadings and temperatures investigated, the lowest cloud point pressure is observed at 46 bar (5 wt % ClPFPE-NH4 in PFPE oil, W0 = 20, xCO2 = 0.7, T = 25 degrees C). In the regions where one-phase behavior is observed, the cloud point pressures increase with temperature, water loadings, and CO2 content. The driving forces of microemulsion formation in the CO2-expanded fluorinated solvent are discussed relative to traditional reverse microemulsions and CO2-continuous microemulsions.     

SYNERGETIC EFFECT OF SUCROSE AND ETHANOL ON FORMATION OF TRIGLYCERIDE MICROEMULSIONS

The phase behavior of soybean oil, a nonionic surfactant (ethoxylated monodiglycerides) and an aqueous phase of water containing ethanol, and sucrose was investigated at 35 and 40°C. A minimum concentration of 20 wt% ethanol was required for the formation of isotropic solutions. Addition of sucrose to the aqueous phase decreased the amount of ethanol required to form these solutions. The solubilization mechanism of the oil was investigated by small angle x-ray diffraction and polarized light microscopy. A stable lamellar liquid crystalline phase was formed for a mixture of 75/25 surfactant/sucrose solution (2.5 wt% sucrose). This phase was destabilized with increased concentrations of sucrose and liquid crystalline phases having hexagonal structures were favored at 8.75 wt% sucrose. At a ratio of 55/45 wt% of surfactant/sucrose solution (9 wt% sucrose) hexagonal structures were formed and could be destabilized or destroyed by addition of ethanol. The concept of stabilization and destabilization of liquid crystalline mesophases was applied to the solubilization of triglycerides in aqueous solutions. Two microemulsion regions were identified; oil-in-water (L₁) and water-in-oil (L₂) in systems containing soybean oil, ethoxylated monodiglycerides, and 20 wt% ethanol solution. At 55/45 wt% surfactant/20 wt% ethanol solution,7.5 wt% of soybean oil was solubilized. Addition of 10, 20, and 30 wt% sucrose, at the same ratio of surfactant to ethanol solution, increased the solubility of the oil to 9, 13.5, and 18 wt% respectively. In addition, the size of the L₁ phase increased and moved to the aqueous corner of the phase diagram and the size of the L₂ phase decreased.     

Surfactant-free oil/water and bicontinuous microemulsion composed of benzene, ethanol and water

<正>Generally,a microemulsion consists of oil,water,surfactant and sometimes cosurfactant.Herein,we report a novel suffactant-free microemulsion(denoted as SFME) composed of benzene,water and ethanol without the amphiphilic molecular structure of traditional surfactant.The phase behavior of the ternary system was investigated,finding that there were a single-phase region and a two-phase region in ternary phase diagram.The electrical conductivity measurement was employed to investigate the microregion of the single-phase region,and a bicontinuous microregion and a benzene-in-water(O/W) microemulsion microregion were identified,which was confirmed by freeze-fracture transmission electron microscopy(FF-TEM) observations.The sizes of the microemulsion droplets are in the range of 20-50 nm.     

Physicochemical Properties and Evaluation of Microemulsion Systems for Transdermal Delivery of Meloxicam

IntroductionMicroemulsion is defined as a dispersed systemconsisting of oil, surfactant, cosurfactant, and anaqueous phase. It is a thermodynamically stable opti-cally transparent isotropic liquid solution with a dropletdiameter usually less than 100 nm[1…     

反相微乳液法制备棒状羟基磷灰石纳米粒子

在(Tritonx-100 Tween 80)，环己烷，(正己醇 正丁醇)，0．5mol／L Ca(NO3)2水溶液反相微乳液体系中，采用滴加0．3mol／L(NH4)2HPO4水溶液的加料方式成功制备出直径在20～25nm，长度在28～64nm的棒状羟基磷灰石纳米粒子。通过对(Triton X-100 Tween 80)，环己烷，(正己醇 正丁醇)／0．5mol／L Ca(NO3)2水溶液三元相图及水溶液反应机理的分析，确定了最佳反相微乳液组成；研究了HLB值和表面活性剂用量对羟基磷灰石颗粒大小的影响。实验结果表明，最佳反相微乳液组成为：47．6(wt)％的环己烷、37．4(wt)％的表面活性剂和助表面活性剂、15(wt)％0．5mol／L的Ca(NO3)2水溶液。     

Sub-zero temperature behaviour of non-ionic microemulsions in the presence of propylene glycol by DSC

The five-component system is quite unique since it allows formation of reverse micelles with hydrophilic ethoxylated alcohol in the presence of ethanol and it facilitates dilution by water/propylene glycol (1,2-propanediol, PG) aqueous phase, all the way from a water-in-oil (W/O) microemulsion via a bicontinuous phase to an oil-in-water (O/W) microemulsion.The surfactant/alcohol/PG can strongly bound water in the inner phase so that it freezes below –10°C and acts in part as bound water and in part as non-freezable water. Upon dilution to >30 mass% aqueous phase (water/PG at constant mass ratio of 1/1) the system becomes bicontinuous and the aqueous layers are composed again from bound water. Even after complete inversion to O/W microemulsions the water in the continuous phase is strongly interacting with the PG/surfactant and remains bound or non-freezable. Water/PG/ethanol have a strong effect on the head groups (freezing below -10°C) and also on the hydrophobic tails (recrystallizing and melting) at lower temperature when dilution exceeds 45 mass% water/PG (1/1).No free water was detected neither in the W/O microemulsion's inner droplet domains nor when the microemulsion was either bicontinuous or when it was inversed to O/W. Continuous phase of resulting O/W microemulsion apparently is based on water/PG at a mass ratio of 1/1.This revised version was published online in November 2005 with corrections to the Cover Date.     

Solubilisation of triolein by microemulsions containing C12E4/hexadecane/water: equilibrium and dynamics

Increasing triolein content of oil-in-water microemulsions in the pure C(12)E(4)/water/n-hexadecane/triolein system while maintaining a fixed surfactant concentration and volume fraction of drops raises the temperature of the solubilisation boundary, where excess oil separates, but has only a slight effect on the (higher) cloud point temperature, where excess water appears. Thus, the temperature range of the single-phase microemulsion shrinks and ultimately disappears. When such microemulsions are in equilibrium with excess oil, the hexadecane/triolein ratio is greater in the microemulsion, probably because the larger triolein molecules are unable to penetrate the hydrocarbon chain region of the surfactant films of the microemulsion droplets. Indeed, monolayer studies and calculations based on microemulsion and excess oil compositions indicate that the films have minimal triolein and similar ratios of hexadecane to surfactant. Triolein drops brought into contact with hexadecane-in-water microemulsions first swell as they incorporate hexadecane, then shrink owing to solubilisation. Interfacial tension decreases during this process until it becomes almost constant near 0.01 mN m(-1), suggesting that the drops in the final stages of solubilisation have high hexadecane contents. A microemulsion containing 10 wt% C(12)E(4) and 15 wt% hexadecane was able to remove over 50% of triolein from polyester fabric at 25 degrees C, more than twice that removed by an oil-free solution with the same surfactant concentration in similar experiments.     

Application of Polyglycerol Diisostearate Ethoxylates in Microemulsion

Effect of surfactants [polyglycerol diisostearate ethoxylates (PGDIS-E31, PGDIS-E36 and PGDIS-E40) and Tween-80], alcohols (1,2-propandiol, ethanol, 1-propanol, 1-butanol, 2-butanol and 1-pentanol), oils [isopropyl palmitate (IPP), isooctyl palmitate (IOP), dioctyl carbonate (DOC), and dioctyl hexanediate (DOH)], temperature and sodium chloride on the microemulsion formation of the surfactant/alcohol/oil/water system has been investigated by the pseudo-ternary phase diagrams. The capacities of the four surfactants in the microemulsion formation of the surfactant/alcohol/IPP/water system at surfactant/alcohol of 2:1 are in the order of PGDIS-E31 > PGDIS-E36 > Tween-80 > PGDIS-E40, whatever alcohol (ethanol, 1-propanol, and 1-butanol) is used. PGDIS-E31 and 1-butanol exhibit best synergism in the microemulsion formation. In addition, the volume, structure and polarity of oil all influence the microemulsion formation. At the optimum weight ratio 2:1 of PGDIS-E31/1-butanol, the microemulsion region of the PGDIS-E31/1-butanol/IPP/water system is the largest among the studied systems. The microemulsion system of PGDIS-E31/1-butanol/IPP/water is not sensitive to lower temperature such as 40°C. It is also not sensitive to sodium chloride when the concentration of sodium chloride is in the range of 0 to 1.0%.     

Influence of Surfactant and Humidity on Sol-Gel Macroporous Organosilicate Coatings

In the preparation of macroporous hydrophobic organosilicate films using methyltriethoxysilane (MTES) as precursor, the effects of surfactant addition, surfactant properties and atmospheric humidity were explored. As films dried, preferential evaporation of the ethanol resulted in an increase of the relative water content. This led to development of phase separation between the hydrophobic gel and the aqueous liquid and ultimately the formation of macropores. In the presence of surfactant, surfactant adsorption at the aqueous phase/gel interface affected the extent of phase separation therefore the resulting pores. Span 20 surfactant (HLB = 8.6) has lower compatibility with the aqueous phase than Tween 20 (HLB = 16.7) and effectively increases the hydrophobicity of the gel phase leading to the formation of larger pores. An increase in Span 20 content from 2 wt.% to 5 wt.% also increased pore size. Film porosity also increased significantly with humidity inside the coating chamber. It would appear that the increased porosity is a result of increased phase separation caused by reduced water evaporation at the higher humidity. Highly macroporous (up to 80% porosity), reproducible and uniform films were obtained by incorporating Span 20 surfactant into the coating solutions and performing dip coating at 80% relative humidity.     

Microemulsification of triglyceride sebum and the role of interfacial structure on bicontinuous phase behavior

A unique triblock surfactant is reported that allows for the efficient microemulsification of triglycerides. Unlike the results of all previous efforts, these triglyceride microemulsions can be formed without the use of cosurfactants or dilution with co-oils and follow the classical patterns of surfactant phase behavior exhibited by mixtures of water, alkane oils, and nonionic oligoethylene glycol surfactants, i.e., progression from oil/water emulsions to one-phase microemulsions to water/oil emulsions with increasing temperature. Lamellar phases that usually dominate the aqueous phase behavior of surfactant/triglyceride mixtures are suppressed, allowing for the formation of single-phase microemulsions containing equal amounts of triglyceride and water. These isotropic and low-viscous fluids are particularly useful for cleansing and delivery of functional ingredients in skin care products. The effects of mixing a variety of typical skin care ingredients and components of sebum (skin oil) were also explored. Fatty acids significantly reduce the average microemulsion temperature, while other ingredients and oils, which do not partition at the oil/water interface, have less impact on the phase behavior. In all cases, one-phase microemulsions containing equal amounts of oil and water can be formed even at high additive concentrations. Indeed, partial replacement oftriglyceride with any of the additives examined consistently reduced the amount of surfactant necessary to form single-phase microemulsions. However, the greatest boost in surfactant efficiency was found with the addition of medium molecular weight amphiphilic block copolymers.     

Microemulsions of Potassium Oleate,Tween-20, Propylene Carbonate,and Ethylene Glycol as Drug Vehicles for Mefenamic Acid

Different microemulsions were prepared with and without mefenamic acid (MFA). The base microemulsion was mainly composed of distilled water; the aqueous phase, propylene carbonate; the oil phase, potassium oleate; the surfactant, and finally di-ethylene glycol; the cosurfactant. The effect of mixing ionic (potassium oleate) with nonionic (Tween-20) surfactant was investigated via constructing the phase diagrams of such systems. Changes in conductivity and viscosity of the freshly prepared microemulsion over time were monitored as an indication for the stability of the microemulsion. Measurements were carried out at room temperature, after a freeze-thaw cycle and also after storage for 3 days at 60°C, where the latter is treated as an accelerated test for the time-temperature effects on the stability of a microemulsion. It was found that a set of surfactants, instead of a single surfactant, and inclusion of cosurfactant resulted in a broader region where a stable microemulsion is predominant. At a mass ratio of 1:2 of potassium oleate to Tween-20, O/W microemulsions were found to have maximum stability among all examined systems, under the accelerated test, such that they have a minimum portion of combined surfactants and cosurfactant of 60 wt% and maximum of 80 wt%. With the aforementioned specifications, no phase separation and neither significant change in the conductivity nor in the viscosity was observed in any of the examined systems after subjecting them both to the accelerated and freeze-thaw cycle test, indicating that such systems were thermodynamically stable. Samples of micro emulsions passing previous tests were further subjected to an acidic medium by dispersing 1 g of MFA-containing microemulsion in 10 g HCl solution (pH 1) in a shaking water bath at 37°C, for a 6 hour period. The maximum solubility of MFA in a stable microemulsion was approximately 5 wt%, evaluated at room temperature.     

Tuning high aqueous phase uptake in nonionic water-in-oil microemulsions for the synthesis of Mn-Zn ferrite nanoparticles: phase behavior, characterization, and nanoparticle synthesis

In this work, the formation of water-in-oil (w/o) microemulsions with high aqueous phase uptake in a nonionic surfactant system is investigated as potential media for the synthesis of Mn-Zn ferrite nanoparticles. A comprehensive study based on the phase behavior of systems containing precursor salts, on one hand, and precipitating agent, on the other hand, was carried out to identify key regions on (a) pseudoternary phase diagrams at constant temperature (50 °C), and (b) pseudobinary phase diagrams at constant surfactant (S):oil(O) weight ratio (S:O) as a function of temperature. The internal structure and dynamics of microemulsions were studied systematically by conductivity and self-diffusion coefficient determinations (FT PGSE (1)H NMR). It was found that nonpercolated w/o microemulsions could be obtained by appropriate tuning of composition variables and temperature, with aqueous phase concentrations as high as 36 wt % for precursor salts and 25 wt % for precipitating agent systems. Three compositions with three different dynamic behaviors (nonpercolated and percolated w/o, as well as bicontinuous microemulsions) were selected for the synthesis of Mn-Zn ferrites, resulting in nanoparticles with different characteristics. Spinel structure and superparamagnetic behavior were obtained. This study sets firm basis for a systematic study of Mn-Zn ferrite nanoparticle synthesis via different scenarios of microemulsion dynamics, which will contribute to a better understanding on the relationship of the characteristics of the obtained materials with the properties of the reaction media.     

Studies on the Phase Behavior of Beta‐cypermethrion Microemulsion

The phase behavior of the system of surfactant SAA [0203B, nonionic surfactant 700# and methanol (weight ratio=6∶1∶1)]/mixed oil [beta‐cypermethrion, dimethyl benzene and cyclohexanone (weight ratio=2∶2∶1,or 0∶2∶1)]/water [distilled water (0 mg/L), or standard water (342 mg/L), or ultra‐hard water (500 mg/L)] has been studied in a pseudoternary phase diagram at 25 ± 1°C. Our results indicated that the isotropic monophasic area in the phase diagrams decreased significantly as the beta‐cypermethrion was added in the oil phase. In an attempt to the microemulsion electrical condectivity can be define regions corresponding to three structure states W/O, B.C., and O/W type in the microemulsion domain. The influence of beta‐cypermethrion on their regions sequences B.C. > O/W?W/O type. This work will be beneficial to improving the quality of beta‐cypermethrion microemulsion and make it more competitive in the market.     

Influence of a cationic polyelectrolyte on the inverse micellar region of the ternary system sulfobetaine/water/alcohol

The influence of the cationic polyelectrolyte poly(diallyldimethylammonium chloride) on structure formation in the inverse micellar region (L2 phase) of the ternary system 3 (N,N-dimethyldodecylammonio)propanesulfonate/alcohol/water has been investigated. Up to a polymer concentration in the aqueous phase of 10 wt %, an isotropic phase still exists. As the chain length of the alcohol component increases, the isotropic phase region is reduced and shifted in direction to the water corner. The isotropic polyelectrolyte-modified L2 phase of the heptanol-based microemulsion has been studied in much more detail by means of conductometric, rheological, and differential scanning calorimetry measurements. The polyelectrolyte-modified microemulsion phase shows a characteristic low shear viscosity and Newtonian flow behavior. The characteristic features of the nonpercolated microemulsion droplets are the low conductivity and the disappearance of bulk water. One can conclude from the experimental data that the individual nonpercolated polyelectrolyte-stuffed microemulsion droplets are approximately uniform in size. In addition, the area of the polyelectrolyte-modified inverse microemulsion phase with heptanol and octanol depends on the temperature. This means that the area of the L2 region can be increased by the temperature being increased from room temperature to 40 °C. This behavior can be explained by a change in the bending elasticity of the surface film induced by Coulombic interactions between the functional groups of the polyelectrolyte and the surfactant head groups. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 742–751, 2004     

Phase behaviour and physicochemical properties of microemulsions with a non-ionic surfactant (IGEPAL)

The non-ionic surfactant pentaethylenglycol-4-octylphenyl ether (igepal CA-520) represents a good industrial alternative to the long-tail members of the C_iE_j family. In this paper, the phase behaviour of the microemulsion system igepal CA-520/n-decane/brine is studied in detail. An isotropic phase was found, as well as liquid crystalline and cream-like structures, depending on composition and temperature. Such structures can either form single-phase homogeneous mixtures, or coexist with other structures when phase separation takes place. Below surfactant concentration of about 20%, more complicated phase equilibria develop as temperature changes. The presence of different additives shifts the temperature ranges where the different phases exist, while keeping the general shape of the phase diagram, which agrees with the general rules for non-ionic surfactants. Complementary rheology experiments reveal a change from non-Newtonian to Newtonian behaviour during the phase transition from a lamellar phase to the isotropic microemulsion. A structure of water droplets associated in clusters can be proposed from SANS and electrical conductivity.     

Microstructures in aqueous solutions of a polyoxyethylene trisiloxane surfactant and a cosurfactant studied by SANS and NMR self-diffusion

Microemulsion samples of a polyoxyethylene trisiloxane surfactant, water, and 1-decanol are investigated using pulsed field gradient NMR and small-angle neutron scattering (SANS) to determine the solution structure. The surfactant/decanol weight ratio has been kept constant at values of 10:1, 8:1, and 6:1 under variation of water content. The temperature was 32 degrees C for the measurement series at the weight ratio of 10:1 to avoid phase separation at high water content. Also, aqueous surfactant solution samples have been investigated as a function of composition and temperature. Water-rich samples consist of micelles that are close to spherical at very low surfactant concentration and grow into anisometric, that is, oblate formed aggregates, at higher surfactant (or surfactant and decanol) concentration. The aggregates grow with increasing temperature, most probably due to dehydration of the hydrophilic groups. In a concentration range around 50 wt % water, the systems form bicontinuous structures. SANS data are used to estimate surfactant film properties using a model developed for interpretation of neutron scattering data from related systems.     

Transport properties of alternative fuel microemulsions based on sugar surfactant

Electrical conductivity of fuel microemulsion composed of diesel, pentanol, water, and sucrose laurate as surfactant was investigated over a wide range of water contents varying from 0 to 90?wt% and temperature varying from 10°C to 50°C. Conductivity measurements were performed on samples, the composition of which lie along the one-phase channel using a conductivity meter. Activation energy of conduction flow was evaluated. The hydrodynamic radius as a function of temperature in the aqueous phase-rich region (90?wt%) was measured using the dynamic light scattering (DLS) method. The microstructure of the microemulsion was further investigated by NMR diffusometry by which the self-diffusion coefficients for water were determined at 25°C. Electrical conductivity increases with water content up to 40?wt% and the percolation threshold was observed, and then stabilizes between 40 and 80?wt% then decreases. Percolation threshold temperature at constant composition was monitored as 36°C for water contents below 80?wt% and as 34°C for water contents above that. As predicted by the conductivity measurements, the determined self-diffusion coefficients of water confirmed the structural transition from discrete W/O droplets to bi-continuous phase and finally to O/W droplet microemulsion.     

Surface and catalytic properties of Cu/Zn mixed oxide catalysts

Copper catalysts supported on zinc oxide, with different loading (1–20 wt.% CuO), were prepared by impregnation of the basic zinc carbonate with a water solution of copper nitrate. The impregnated samples were dried at 120°C and calcined at 400–700°C. The surface and catalytic properties of CuO loaded on ZnO were determined by N₂ adsorption measurements conducted at −196°C and CO oxidation by O₂ at 150–300°C, respectively. The results obtained revealed that the surface and catalytic properties of different solids were dependent upon CuO content and calcination temperature. The specific surface areas of various adsorbents decreased monotonically as a function of both calcination temperature and extent of loading. However, the activation energy of sintering, ΔE_S, was found to increase by increasing the amount of CuO present. On the other hand, the CO oxidation activity on various catalysts was found to increase progressively by increasing the calcination temperature from 400 to 500°C, then decreased by increasing the temperature from 500 to 700°C. The augmentation of CuO content from 1 to 5 wt.% resulted in an increase in the CO oxidation activity, which decreased by increasing the extent of loading above this limit.     

Investigations into the formation and characterization of microemulsions. I. Phase diagrams of the ternary system water—sodium alkyl benzene sulfonate—hexanol and the quaternary system water—xylene—sodium alkyl benzene sulfonate—hexanol

The phase diagrams of the ternary system water—sodium alkylbenzene sulfonate (NaDBS)-hexanol and the quaternary system water—xylene—NADBS—hexanol have been established at three different temperatures, namely 25, 37, and 50°C. The different phases formed have been qualitatively examined using optical (phase contrast and polarizing) microscopy. The textures of the various liquid crystalline phases in the ternary system have been identified, by comparison with previous studies in the literature. Some of the liquid crystalline phases have been quantitatively assessed using low angle X-ray diffraction. The latter measurements were also used to determine the unit cell dimensions in the various phases studied. With the quaternary system, particular attention was paid to the transparent region which consisted of an L₂ (inverse micellar) phase extending into another transparent region which has a blue “tinge” in some cases, namely the microemulsion (M) region. The amount of water solubilized in the L₂ (reverse micelle) or M + L₂ phase was calculated from the phase diagrams. With the ternary system the results showed a maximum in moles of water solubilized per mole total surfactant (NaDBS + hexanol) at a concentration of 0.3 mole surfactant, at an optimum molar ratio of n-hexanol to NaDBS of 4.5:1. This maximum was about twice with the quaternary system, when compared with that of the ternary system, indicating the importance of the role of xylene in solubilization of water by the surfactants. The present investigation has also shown that the extent of the microemulsion region is significantly reduced by increases of temperature when the NaDBS is lower than 15 wt%.     

Synthesis of industrial scale NaY zeolite membranes and ethanol permeating performance in pervaporation and vapor permeation up to 130 °C and 570 kPa

NaY zeolite tubular membranes in an industrial scale of 80 cm long were synthesized on monolayer and asymmetric porous supports. The quality of synthesized membranes were evaluated by pervaporation (PV) experiments in 80 cm long at 75 °C in a mixture of water (10 wt.%)/ethanol (90 wt.%), resulting in higher permeation fluxes of 5.1 kg m⁻² h⁻¹ in the monolayer type membrane and of 9.1–10.1 kg m⁻² h⁻¹ in the asymmetric-type membranes, respectively. The uniformity with small performance fluctuation in longitudinal direction of the membranes were observed by PV for 10–12 cm long samples at 50 °C in a mixture of methanol (10 wt.%)/MTBE (90 wt.%). The ethanol single component permeation experiments in PV and vapor permeation (VP) up to 130 °C and 570 kPa were performed to determine the relations between the ethanol flux and the ethanol pressure difference across the membrane which is represented by permeance (Π, mol m⁻² s⁻¹ Pa⁻¹) for estimate of potential of ethanol extraction through the present NaY zeolite membranes applying feasible studies. Results indicate that (1) the permeation fluxes are linearly proportional to the driving force of vapor pressure for each sample in VP and PV. The permeances through an asymmetric support type membrane were rather constant of 0.6–1.2 × 10⁻⁷ mol m⁻² s⁻¹ Pa⁻¹ in the wide temperature range of 90–130 °C in PV and VP, indicating that the ethanol permeances have weak temperature dependency with the feed at the saturated vapor pressure.

The results of superheating VP experiments showed that ethanol permeation fluxes are increased with increasing of the degree of superheating at a given constant feed vapor pressure. The ethanol permeances are increased with increasing of temperature at a given feed vapor pressure. The superheating VP could be a feasible process in industry.