Pure 1-butanol Research Articles

Flow boiling in a rectangular micro/mini channel with self-rewetting and non-rewetting fluids

In this experimental investigation the influence of self-rewetting during flow boiling was studied in a horizontal microchannel during one-sided uniform heating. The channel had a width and height of 6 mm and 0.3 mm respectively. Local wall temperature and direct in-time flow visualisation was performed. The working fluids under consideration included water as base reference, pure 1-butanol, pure ethanol, dilute butanol-water self-rewetting mixtures, and a dilute ethanol-water binary mixture. Tests were conducted at mass fluxes of 10, 15 and 25 kg/m2s, over a range of heat fluxes to produce both single phase and two-phase quasi steady state flow data. Within the wall temperature ranges of interest, the butanol-water mixtures (5 % and 7 % by volume butanol) had surface tension characteristics that would draw liquid toward local wall hotspots. Local and average wall temperatures and heat transfer coefficients were obtained and considered against the governing flow pattern visualisations. In contrast to the other fluids, the self-rewetting butanol-water mixtures exhibited significantly more stable flow and more predictable saturation flow boiling heat transfer coefficient trends across all heat fluxes under consideration. At the lowest mass flux, it was found that an increase in the heat flux resulted in an improvement in the self-rewetting fluids heat transfer performance, while at higher mass fluxes this dependence was diminished. Across all mass fluxes and heat fluxes the 5 % butanol-water outperformed its 7 % butanol-water counterpart. The tendency of self-rewetting to reduce local dry-out, even at low mass fluxes are demonstrated.

Self-assembly of superstructures at all scales

Summary Controllable assembly of molecular and nanoscale building blocks into uniform superstructures up to bulk dimensions remains a key challenge in the next phase of nanotechnology development. Here, we report the self-assembly of superstructures at all scales by taking advantage of the partial miscibility of water and 1-butanol to generate transient aqueous emulsion droplets that can encapsulate the target materials and introduce them into template holes. Further diffusion of water into 1-butanol depletes the emulsion droplets, assembling the building blocks into one well-defined superstructure in each hole. Superstructuring of various types and shapes of nanoparticles, biomolecules, and inorganic compounds could be achieved without the need for surfactants and chemical modifications. The versatility, scalability, low-cost, and accurate positioning are crucial advantages for the future development of advanced precision manufacturing.

Effect of Solvent Properties and Composition on the Solubility of Ganciclovir Form I

Characterization of physical properties of polymorphs in pharmaceuticals is a very important aspect of drug development and manufacturing. This work is to improve the solubility and calculate dissolution thermodynamics of ganciclovir form I. An isothermal saturation method was applied to measure the solubility values of ganciclovir form I in some pure and mixed solvents at temperatures ranging from 278.15 to 318.15 K at atmospheric pressure. The solubility obtained a maximum value in pure 1-butanol and a minimum data in neat toluene. The obtained solubility data of ganciclovir form I in pure solvents were correlated with the modified Apelblat equation, the λh equation, and the NRTL model. Meanwhile, the Jouyban–Acree model was applied to simulate ganciclovir form I solubility in binary mixture compositions at various temperatures. The maximum value of the relative average deviation (RAD) was 3.04%, which indicates the experimental data was well consistent with the calculated ones. Apparent thermodynamic a...

Marangoni Flow Induced Evaporation Enhancement on Binary Sessile Drops.

The evaporation processes of pure water, pure 1-butanol, and 5% 1-butanol aqueous solution drops on heated hydrophobic substrates are investigated to determine the effect of temperature on the drop evaporation behavior. The evolution of the parameters (contact angle, diameter, and volume) during evaporation measured using a drop shape analyzer and the infrared thermal mapping of the drop surface recorded by an infrared camera were used in investigating the evaporation process. The pure 1-butanol drop does not show any thermal instability at different substrate temperatures, while the convection cells created by the thermal Marangoni effect appear on the surface of the pure water drop from 50 °C. Because 1-butanol and water have different surface tensions, the infrared video of the 5% 1-butanol aqueous solution drop shows that the convection cells are generated by the solutal Marangoni effect at any substrate temperature. Furthermore, when the substrate temperature exceeds 50 °C, coexistence of the thermal and solutal Marangoni flows is observed. By analyzing the relation between the ratio of the evaporation rate of pure water and 1-butanol aqueous solution drops and the Marangoni number, a series of empirical equations for predicting the evaporation rates of pure water and 1-butanol aqueous solution drops at the initial time as well as the equations for the evaporation rate of 1-butanol aqueous solution drop before the depletion of alcohol are derived. The results of these equations correspond fairly well to the experimental data.

Bubble rise in a non-isothermal self-rewetting fluid and the role of thermocapillarity

We report on the motion of a buoyancy-driven bubble in a vertical micro-channel and the significant role of thermocapillarity. A series of experiments have been carried out using a circular micro-channel filled with pure liquids (pure water and pure 1-butanol) and a self-rewetting fluid (water – 1-butanol 5% vol.) under isothermal and non-isothermal controlled conditions. In both cases, different mass fluxes and heat fluxes were applied on the micro-channel within the same temperature gradient field (18 °C–75 °C) which was increasing linearly in the same direction with the liquid flow. We have shown that the behaviour of the bubbles in a self-rewetting fluid departed considerably from that of pure liquids. The anomalous property of the alcohol mixture, i.e. the quasi-parabolic dependence of the surface tension with the temperature, drastically modified the movement (promoted or inhibited) and the shape (spherical or deformed) of the migrating bubbles. These phenomena were explained in terms of the location of the bubble associated with the well-defined surface tension minimum, and as a function of dimensionless numbers. Heat transfer coefficient calculations in the single and two-phase flows were acquired for all the liquids used. We demonstrated that the presence of Marangoni stresses resulted in the enhancement of the heat transfer distribution in the self-rewetting fluid flows compared to the pure liquids.

Solubility of Amorphous Clopidogrel Hydrogen Sulfate in Different Pure Solvents

At the temperature range (273.15 to 308.15) K, the solubility of amorphous clopidogrel hydrogen sulfate (CHS) in pure 1-butanol, 2-butanol, 2-propanol, methyl acetate, ethyl acetate, acetone, and methyl tert-butyl ether (MTBE) were experimentally measured. The order of solubility of amorphous CHS is 1-butanol > acetone > 2-propanol > 2-butanol > methyl acetate > ethyl acetate > MTBE, which is in good agreement with the orders of CHS crystalline forms in the literature. However, the solubility of the amorphous ones is dozens of times higher than that of crystals, respectively. In addition, the modified Apelblat equation was used to correlate the temperature with the mole fraction solubility. Finally, the thermodynamic parameters were calculated by the fitting parameters of the modified Van’t Hoff equation.

P–ρ–T Data for 1-Butanol and Isobutyl Alcohol from (283.15 to 363.15) K at Pressures up to 66 MPa

We present densities of pure 1-butanol and isobutyl alcohol from (283.15 to 363.15) K at pressures up to 66 MPa. We have measured densities using a vibrating tube densimeter. We use a forced path calibration method since this method depends mainly upon the mechanical properties of the cell. Experimental measurements of n-heptane have been measured to test the reliability of the apparatus. These measurements agree with a reference equation of state within 0.1 %. The new experimental densities of 1-butanol and isobutyl alcohol agree within 0.2 % with densities from the literature.

Solubility of carbon dioxide, methane, and ethane in 1-butanol and saturated liquid densities and viscosities

A designed pressure–volume–temperature (PVT) apparatus has been used to measure the (vapor+liquid) equilibrium properties of three binary mixtures (methane +, ethane +, and carbon dioxide + 1-butanol) at two temperatures (303 and 323)K and at the pressures up to 6MPa. The solubility of the compressed gases in 1-butanol and the saturated liquid densities and viscosities were measured. In addition, the density and viscosity of pure 1-butanol were measured at two temperatures (303 and 323)K and at the pressures up to 10MPa. The experimental results show that the solubility of the gases in 1-butanol increases with pressure and decreases with temperature. The dissolution of gases in 1-butanol causes a decline in the viscosity of liquid phase. The saturated liquid density follows a decreasing trend with the solubility of methane and ethane. However, the dissolution of carbon dioxide in 1-butanol leads to an increase in the density of liquid phase. The experimental data are well correlated with Soave–Redlich–Kwong (SRK) and Peng–Robinson (PR) equations of state (EOSs). SRK EOS was slightly superior for correlating the saturated liquid densities.

Assembly of biomacromolecule loaded polyelectrolyte multilayer capsules by using water soluble sacrificial templates

In the quest for greater control over biomacromolecular loading and higher encapsulation efficiencies for biomacromolecule loaded microcapsules we devised a novel approach employing water soluble sacrificial templates. In traditional layer by layer (LbL) methods, aqueous solutions of polyelectrolyte salts in combination with water insoluble sacrificial template materials are used to prepare polyelectrolyte microcapsules that can be loaded with biomacromolecules. Here, we replaced the aqueous phase with pure aliphatic alcohols (Reversed-Phase) to greatly enhance the retention of biomacromolecular cargo close to 100% during microcapsule preparation in this Reverse-Phase Layer by Layer (RP-LbL) process. Formation of stable multilayered polyelectrolyte membranes onto water soluble template materials by sequential deposition of polystyrenesulfonic acid (PSS) and polyallylamine (PA) from pure 1-butanol is reported for the first time. The challenge to exert control over the biomacromolecule concentration within the template material and the resulting microcapsules was addressed by sacrificial template materials. Sacrificial template materials are water soluble and comprise of biomacromolecules embedded into a matrix of small molecular weight molecules such as glucose. Control over the concentration of biomacromolecules in the template material and microcapsules is conveniently exerted by adjusting weight ratios of bimacromolecules to sacrificial template material. This approach is envisioned to be applied alternatively to traditional polyelectrolyte microcapsule preparation techniques in cases where minute losses of expensive biomacromolecules are unfavorable or when accurate control over biomacromolecule concentration is important.

Physico-chemical properties of binary mixtures of 1-butanol with chloroethanes or chloroethenes at 298.15 K

The densities ρ, speeds of sound u, and viscosities η, of pure 1-butanol, 1,2-dichloroethane, 1,1,1-trichloroethane, 1,1,2,2-tetrachloroethane, trichloroethylene, and tetrachloroethylene and those of their binary mixtures have been measured at 298.15 K and atmospheric pressure over the entire range of compositions. Excess molar volumes V E, viscosity deviations Δη, deviation in compressibilities Δκs and excess Gibbs energy of activation G*E, were obtained from the experimental results and those were fitted to Redlich–Kister's type function in terms of mole fractions. Viscosities, speeds of sound and isentropic compressibilities of the binary mixtures have been correlated by means of several empirical and semi-empirical equations. The experimental data are analysed to discuss the nature and strength of intermolecular interactions in these mixtures.

A novel pycnometer for density measurements of liquids at elevated temperatures

A novel pycnometer has been designed for density measurements at elevated temperatures (up to T=473.15 K). The pycnometer consists of a stainless steel cell connected to a small-bore tube. The main feature of the design includes a bored-through expansion fitting, which allows the overflow due to thermal expansion from the cell (via the small-bore tube) to collect in a pressurized line. Densities were measured for pure 1-butanol, pure n-heptane, and for mixtures { x bCH 3(CH 2) 3OH + (1− x b)CH 3(CH 2) 5CH 3}, from T=316.85 K to T=458.15 K, at a pressure of 4.93 MPa. Excess volumes were calculated and reported for these mixtures.

Solvent effects on the reactivity of solvated electrons with ammonium and nitrate ions in 1-butanol–water solvents

Values of the rate constants, k2 (106 m3 mol−1 s−1), of solvated electrons,[Formula: see text] with several related salts, in pure water and pure 1-butanol solvents at 298 K are, respectively, as follows: LiNO3, 9.2, 0.19; NH4NO3, 10, 8.3; NH4ClO4, 1.5 × 10−3, 12 in 20 mol% water; LiClO4, 1.0 × 10−4, < 1.0 × 10−4. The value of [Formula: see text] in water solvent is 48 times larger than that in 1-butanol solvent, whereas [Formula: see text] in water is 10−4 times smaller than the value in 1-butanol. This enormous reversal of solvent effects on [Formula: see text] reaction rates is the first observed for ionic reactants. The solvent participates chemically in the [Formula: see text] reaction, and the overall rate constant increases with increasing viscosity and dielectric relaxation time. This unusual behavior is attributed to a greatly increased probability of reaction of an encounter pair with increasing duration of the encounter. Effective reaction radii κRr for [Formula: see text] and [Formula: see text] were estimated with the aid of measured electrical conductances of the salt solutions in all the solvents. Values of κRr are (2–7) × 10−10 m, except for NH4,s+ in 100 and 99 mol% water, which are 2.6 and 2.7 × 10−14 m, respectively. The effective radii of the ions for mutual diffusion increase with increasing butanol content of the solvent, from ~50 pm in water to ~150 pm in 1-butanol, due to the increasing average size of the molecules that solvate the ions.

Conductivity measurements in single-phase microemulsions of the system sodium dodecyl sulfate/1-butanol/water/heptane

Conductivity measurements have been performed in the single-phase region of the system sodium dodecyl sulfate (SDS)/1-butanol/water/heptane at 25°C. The applicability of the classical conductance theory for weak electrolytes, the semiempirical conductance theory for coarse emulsions, and the percolation theory has been examined. These measurements reveal that SDS micelles are converted into monomers in the presence of a sufficient amount of 1-butanol. In almost pure 1-butanol as a solvent, SDS behaves as a weak 1-1-electrolyte. At a certain water-to-heptane ratio at constant total amount of SDS and 1-butanol, the conductivity results indicate where a transition from water-in-oil to oil-in-water microemulsions takes place, and the transition can be described by the percolation theory.