Secondary Butyl Alcohol Research Articles

Application of Cu/SiO2 Catalysts Prepared by Different Methods in Dehydrogenation Reaction of Secondary Butyl Alcohol

Application of Cu/SiO2 Catalysts Prepared by Different Methods in Dehydrogenation Reaction of Secondary Butyl Alcohol

Cu–Ni/SiO2 Catalysts for Dehydrogenation Reaction of Secondary Butyl Alcohol

Cu–Ni/SiO2 Catalysts for Dehydrogenation Reaction of Secondary Butyl Alcohol

Phase diagram in cyclopentanone + water + secondary butyl alcohol and light scattering investigations near the LCST

We report light scattering investigations and study of phase diagram in the system cyclopentanone (CP) + water (W) + secondary butyl alcohol (sBA), a more promising system for exploring the Quadruple Critical Point (QCP) as compared to methyl ethyl ketone (MEK) + W + sBA. Unlike in MEK + W + sBA [A. P. Naseer and P. K. M. Unni, J. Mol. Liq., 296, 111,776 (2019)], the diameter of the tunnel D≡TU-TL decreases from 66.626 K at XCP≡Xketone = 0.1000 to 24.926 K at Xketone = 0.2500 without addition of a fourth component. Our studies indicate that addition of only 0.0018 weight fraction of KSCN (i.e., 5% of the concentration of KSCN required in case of the system MEK + W + sBA), is sufficient to split the tunnel-like portion into two paraboloids with an intervening one-phase region in between. The tunnel-like feature in the phase diagram of CP + W + sBA occurs for 0.1000≤XCP≤0.2000 and for XCP>0.2000, the tunnel is open towards higher water weight fractions, though the critical line of UCSTs and LCSTs is continuous. Light scattering investigations show Fisher renormalization of the susceptibility exponent γ for 0.1750≤Xketone≡XCP≤0.2500 with a near complete renormalization observed for Xketone≡XCP = 0.2500 and normal Ising exponents observed for the region 0.1750>Xketone≡XCP>0.2500. Similarly, Ising-like behavior is observed at both low and high XCP weight-fractions while a tendency for mean-field behavior is observed for Xketone = 0.2500. Both these features appear generic to ternary systems involving (ketone + water + secondary butyl alcohol). The correlation length amplitude of critical concentration fluctuation ξ0 starts from a value of 6.5Å for XCP = 0.15 and saturates at 8.5Å in the range 0.175≤XCP≤0.350.

Light scattering investigations in the system methyl ethyl ketone + water + secondary butyl alcohol with traces of potassium thiocyanate

The effect of trace amounts of potassium thiocyanate (KSCN) at weight fractions XKSCN = 0.0300, 0.0319 and 0.0320 – the weight fractions at which no particular structural peculiarities exist in the phase diagram of MEK + W + sBA + KSCN; presence of critical endpoints (CEPs) are detected and coexistence domes with minimal separation between the vertices containing double critical points (DCPs) are formed in the phase diagram, respectively [Naseer A. P. et. al., J. mol. Liq. 296 (2019)] – on the critical behaviour of the system methyl ethyl ketone (MEK) + water(W) + secondary butyl alcohol (sBA) are investigated through thelight scattering technique. For MEK weight fractions (x) in the range of 0.1000 ≤ x ≤ 0.1800 at constant XKSCN = 0.0300 near Ising-type behavior is observed for experimental paths approaching both TL from below and TU from the above, while in the range of 0.2000 ≤ x ≤ 0.2100 the samples show a clear mean-field type of behavior both at the TL as well as TU. Investigations near the DCPs corresponding to the minimum approach of the two coexistence domes (i.e., at x = 0.1419 and 0.1608 at XKSCN = 0.0320) do not result in the well-established, doubling of critical exponents γ and ν due to inherent chemical complexities in the system MEK + W + sBA + KSCN. FTIR and LC-HRMS studies establish that the formation of the isothiocyanate-isomer of α-thiocyanated methyl-ethyl-ketone resulting from prolonged exposure to elevated temperatures during the course of the light-scattering experiments, is responsible for the results.

Effect of potassium thiocyanate on the phase diagram of Methyl Ethyl Ketone + secondary Butyl Alcohol + Water: Search for the Quadruple Critical Point

The effect of addition of small amounts of the ionic impurity Potassium Thiocyanate (KSCN) on the tunnel-like region in the phase diagram of Methyl Ethyl Ketone (MEK) + secondary Butyl Alcohol (sBA) + Water (W) is investigated in detail. The KSCN weight fraction range, 0 ≤ XKSCN ≤ 0.0318, results in a systematic decrease in the diameter of the critical-tunnel from ΔT = 71.416 K at XKSCN = 0, to ΔT = 5.275 K at XKSCN = 0.0315. For 0.03190 ≤ XKSCN ≤ 0.03195 the line of critical points end abruptly at specific values of water weight fractions (XW) resulting in the formation of several critical end points. For XKSCN ≥ 0.0320 the critical-tunnel splits into several pairs of parabolic critical lines, each carrying double critical points (DCPs) at their vertices, with one-phase region in-between. The distance between the DCPs corresponding to the low- and high-MEK regions can be made to approach or recede from each other depending on the KSCN weight fraction. The QCP in this system is pushed into a hypothetical region due to curvature effects of the coexistence surface in MEK + W + sBA + KSCN.

Systematically quantifying oil–water microemulsion structures using (spin-echo) small angle neutron scattering

Microemulsion systems consisting of D2O, an alkane, an anionic internal olefin sulfonate surfactant, salt and secondary butyl alcohol (SBA) as co-solvent are studied in a systematic way. In four different sample sets, either the salt content, SBA content or alkane carbon number was varied in order to study the effects of the individual compounds on the structure sizes making up the microemulsion. Using complementary small-angle neutron scattering techniques SANS and Spin-Echo SANS, it was found that the microemulsion systems exhibit the largest structures in the optimum state (domain size of d/2 =144 nm in the model by Teubner and Strey), where the structure is considered bicontinuous. In comparison, at under- and over-optimum states where the structures consist of emulsified spherical droplets, the smallest measured diameter was 2R = 44 nm. Furthermore, the structure sizes in bicontinuous microemulsions decrease exponentially (down to d/2 =15 nm for pentadecane and 5 wt% SBA) as function of both SBA content and alkane carbon number. The observed trends in structure sizes combined with the trends observed in the area per surfactant molecule, are qualitatively explained with the extended Winsor R-ratio, the HLD-NAC model and surfactant film flexibility arguments.

Concentrating Nucleic Acids by Extraction with Butanol.

During extraction of aqueous solutions with solvents such as secondary butyl alcohol (isobutanol) or n-butyl alcohol (n-butanol), a proportion of the water molecules is partitioned into the organic phase. Nucleic acids remain in the aqueous phase. By performing several sequential cycles of extraction, the volume of a nucleic acid solution can be reduced significantly. This method of concentration can be used to reduce the volume of dilute solutions to the point where the nucleic acid can be recovered easily by precipitation with ethanol.

Investigation of Influences of Secondary Butyl-alcohol Blends on Performance and Cycle-to-cycle Variations in a Spark Ignition Engines

Depletion of fossilised fuels coupled with stringent energy security has directed automotive researches to continuously investigate the use of alternative fuels in internal combustion engines. Within this subject, the research presented in this work is focused on using butanol as gasoline fuels substitution in a spark ignition engines. The present study reveals the combustion analysis specifically on cycle-to-cycle variations in spark ignition engines and performance characteristics of secondary butyl alcohol (sec-butanol) – gasoline blends at 5%, 10% and 15% by volume of sec-butanol in gasoline fuels. The engine performance characteristics was evaluated at 1000 to 4000 RPM with 50% of wide open throttle positions, while the in-cylinder pressure data were collected over 200 consecutive engine cycles for engine test at 3500 RPM. The indicated mean effective pressure time series is analyzed using the coefficient of variations and the wavelet analysis method. Comparative analysis of the performance characteristics showed that 2-butanol–gasoline blended fuel produced less brake power and brake mean effective pressure by 12.3%, 9.2% and 4.3%, for GBu5, GBu10 and GBu15, respectively, with regard to G100. From the wavelet power spectrum, it is observed that the long-term periodicities appear in gasoline fuels, while the short period oscillations become intermittently visible in blended fuels. Reduction of coefficient of variations occur as the additive of sec-butanol ratios increased, which agrees with the wavelet analysis results. Furthermore, the spectral power reduced with an increase in the additive ratio, indicating that the additive has a noticeable influence on reducing the cycle-to-cycle variations.

Investigation of emissions characteristics of secondary butyl alcohol-gasoline blends in a port fuel injection spark ignition engine

Exhaust emissions especially from light duty gasoline engine are a major contributor to air pollution due to the large number of vehicles on the road. The purpose of this study is to experimentally analyse the exhaust pollutant emissions of a four-stroke port fuel spark ignition engines operating using secondary butyl alcohol–gasoline blends by percentage volume of 5% (GBu5), 10% (GBu10) and 15% (GBu15) of secondary butyl- alcohol (2-butanol) additives in gasoline fuels at 50% of wide throttle open. The exhaust emissions characteristics of the engine using blended fuels was compared to the exhaust emissions of the engine with gasoline fuels (G100) as a reference fuels. Exhaust emissions analysis results show that all of the blended fuels produced lower CO by 8.6%, 11.6% and 24.8% for GBu5, GBu10 and GBu15 respectively from 2500 to 4000 RPM, while for HC, both GBu10 and GBu15 were lower than that G100 fuels at all engine speeds. In general, when the engine was operated using blended fuels, the engine produced lower CO and HC, but higher CO2.

Solubility of Carbon Dioxide in Secondary Butyl Alcohol at High Pressures: Experimental and Modeling with CPA.

Mixtures of carbon dioxide and secondary butyl alcohol at high pressures are interesting for a range of industrial applications. Therefore, it is important to have trustworthy experimental data on the high-pressure phase behavior of this mixture over a wide range of temperatures. In addition, an accurate thermodynamic model is necessary for the optimal design and operation of processes. In this study, bubble points of binary mixtures of CO2 + secondary butyl alcohol were measured using a synthetic method. Measurements covered a CO2 molar concentration range of (0.10–0.57) % and temperatures from (293 to 370) K, with pressures reaching up to 11 MPa. The experimental data were modelled by the cubic plus association (CPA) equation of state (EoS), as well as the more simple Soave–Redlich–Kwong (SRK) EoS. Predictive and correlative modes were considered for both models. In the predictive mode, the CPA performs better than the SRK because it also considers associations.

Heterogeneous reactive extraction for secondary butyl alcohol liquid phase synthesis: Microkinetics and equilibria

The reaction kinetics for the liquid phase synthesis of a racemic mixture of the secondary butyl alcohols (SBA) from linear butene isomers (1-butene (1B); cis-2-butene ( c2B); trans-2-butene ( t2B)) and water (W) using a macroporous sulfonic acid ion exchange resin as catalyst were determined experimentally in a multiphase CSTR in the temperature range 39–433 K at 6–8 MPa. This range of pressures is necessary to dissolve butenes in the aqueous phase and to ensure a liquid state of all components. For temperatures higher than 423 K the reaction kinetics for the used catalyst size are influenced by mass transfer resistances within the catalyst matrix. The reaction takes place in the water swollen gel phase of the catalysts microspheres. Due to the large excess of water in the gel phase the compositions in the gel phase, in the macropore fluid, and in the catalyst surrounding aqueous phase are assumed to be identical. According to the literature the reaction is rather catalyzed by hydrated acid protons ( specific catalysis) than by polymer-bonded-SO 3H groups ( general catalysis). The experimental results can therefore be described sufficiently by a pseudo-homogeneous 3-parameter rate expression in aqueous phase activities. The forward reaction is first-order in butene. The reverse reaction is first-order in secondary butyl alcohol. The activation energy was determined to be 108 kJ/mol. Practically no pressure dependence could be observed for pressures exceeding 6 MPa. The ever-present isomerization of the linear butenes on acid catalysts was found to be remarkably faster than the hydration of butenes to SBA. Therefore, the isomerization is considered to be always in equilibrium during the olefin hydration. The formation of the possible by-product di- sec-butyl ether (DSBE) was never observed to a measurable extent. Simultaneous chemical and phase equilibria were investigated theoretically using the volume translated Peng–Robinson equation of state (VTPR-EoS) in combination with a g E -mixing rule. Parameters of the used g E -model were adjusted to experimental ternary liquid–liquid equilibrium (LLE) data.

Methyl ethyl ketone+water+secondary butyl alcohol: A potential system for the exploration of a quadruple critical point

We report preliminary experiments on the ternary-liquid mixture, methyl ethyl ketone (MEK)+water (W)+secondary butyl alcohol (sBA)--a promising system for the realization of the quadruple critical point (QCP). The unusual tunnel-shaped phase diagram shown by this system is characterized and visualized by us in the form of a prismatic phase diagram. Light-scattering experiments reveal that (MEK+W+sBA) shows near three-dimensional-Ising type of critical behavior near the lower critical solution temperatures, with the susceptibility exponent (gamma) in the range of 1.217< or =gamma< or =1.246. The correlation length amplitudes (xio) and the critical exponent (nu) of the correlation length (xi) are in the ranges of 3.536< or =xio < or =4.611 A and 0.619< or =nu< or =0.633, respectively. An analysis in terms of the effective susceptibility exponent (gammaeff) shows that the critical behavior is of the Ising type for MEK concentrations in the ranges of 0.1000< or =X< or =0.1250 and X> or =0.3000. But, for the intermediate range of 0.1750< or =X<0.3000, the system shows a tendency towards mean-field type of critical behavior. The advantages of the system (MEK+W+sBA) over the system (3-methylpyridine+water+heavy water+potassium Iodide) for the realization of a QCP are outlined.

Regression analysis of electrocapillary curves of mercury electrode in solutions of secondary butyl alcohol

A regression technique is used for analyzing electrocapillary curves (ECC) in secondary butanol solutions, which were published earlier. It was shown that, in contrast to similar analysis of electrocapillary curves for a number of other compounds, if we want to describe the adsorption of 2-BuOH within the framework of the model of two parallel capacitors, the linear dependence of the parameter of intermolecular interaction on the electrode potential should be taken into account. This result stems from the very high accuracy of interface tension measurements in the system under study. It is found that, in terms of the Frumkin isotherm and the model of two parallel capacitors, the interpretation of data on the adsorption of 2-BuOH has a much simpler physical meaning as compared with the strictly thermodynamic approach used earlier.

Fabrication of silicon field emission points for vacuum microelectronics by wet chemical etching

The fabrication of sharp silicon tips for field emission cathodes has been investigated using anisotropic and isotropic wet chemical etching techniques. Formulations of potassium hydroxide, water and alcohol are used as the anisotropic etchants. The effects of isopropyl, secondary butyl and tertiary butyl alcohols on tip formation are examined. An isotropic etchant using a mixture of hydrofluoric, nitro and acetic acids is also used to form similar cathode structures for comparison. The silicon needles formed are intended for use in vacuum microelectronic devices.

Critical point shifts in binary fluid mixtures

An empirical observation is made of an apparent universal shift in the consolute point (Xc=critical composition, Tc=critical temperature) of binary fluid mixtures when the system identity is perturbed. The shift in a ‘‘pure’’ system’s critical point (Xco, Tco) when perturbed becomes (Xc,Tc) which seems to obey (Tc−Tco)/Tco= (Xc−Xco)/Xco. This relation has been observed to hold in a wide range of systems including closed-loop coexistence curves (guaiacol–glycerol–water, or tertiary butyl alcohol in secondary butyl alcohol and water), deuterated systems (methanol–cyclohexane, or isobutyric acid–water), impurities added to methanol–cyclohexane, the molecular weight dependence in polystyrene–methylcyclohexane, and the pressure dependence of methanol–cyclohexane.

Cloud-point measurements for the mixture tertiary butyl alcohol, secondary butyl alcohol, and water

Cloud point measurements are presented for the ternary mixture of tertiary butyl alcohol (tBA), secondary butyl alcohol (sBA), and water. At a zero tBA concentration the system displays a large immiscibility gap, but with an increasing proportion of tBA, the gap pinches off at a critical double point to a closed loop and a lower gap, then the loop shrinks and disappears at a hypercritical point, leaving only the lower gap. This behavior is shown to be semiquantitatively similar to the behavior of sBA/water with increasing pressure. If a pseudobinary assumption is made, the shape of the cloud-point curves can be shown to be qualitatively similar to coexistence curves in binary mixtures, with an exponent of β ≃ 1/3. Near the critical double point this exponents appears to double.

Light-scattering studies of a ternary mixture: Comparison of field variables for critical phenomena description

We present static turbidity and dynamic light-scattering measurements near the critical double point of a mixture of secondary butyl alcohol, tertiary butyl alcohol, and water. At the critical double point of this mixture an upper two-phase miscibility loop merges with a lower two-phase region. When temperature is used as a field variable to describe the critical behavior of the turbidity and correlation length of the mixture, nonuniversal behavior is seen in both the critical exponents and amplitudes. If, however, the tBA concentration difference from the critical curve is used, universality is found in both exponents and amplitudes. We thus term this concentration difference to be the relevant parameter for proper description of the critical behavior and, following Griffiths and Wheeler [Phys. Rev. A 2, 1047 (1970)], show this relevant parameter was determined by it never having tangential paths of approach to the critical curve.

The genetic toxicology of some hydrocarbon and oxygenated solvents.

Two hydrocarbon solvents (heptane and Special Boiling Point Spirit 100/140) and eight oxygenated solvents [methyl ethyl ketone, methyl isobutyl ketone, diacetone alcohol, di-isobutyl ketone, isopropyl ether, hexylene glycol, secondary butyl alcohol and ME 6K (pentoxone)] have been tested for genotoxic activity. The solvents were tested in bacterial mutation assays, a yeast assay for mitotic gene conversion and in cultured mammalian cells (either rat liver or Chinese hamster ovary) for structural chromosome damage. All of the solvents gave a negative response in the bacterial mutation assays and the yeast mitotic gene conversion assay. In the rat liver chromosome assay, diacetone alcohol evoked a weak positive response, the remaining solvents gave a negative response.

Heterogeneous azeotropic distillation: Experimental and simulation results

AbstractExperimental measurements for an industrial azeotropic distillation tower that dehydrates secondary butyl alcohol (SBA) show erratic operation that only approaches a steady state. These are explained with steady‐state simulations which show that slight variations in the aqueous reflux rate cause many trays to shift from homogeneous to heterogeneous operation, accompanied by significant changes in the SBA purity, with water or entrainer contaminating the bottoms product. When other methods failed, an arc‐length homotopy‐continuation method made small adjustments in the reflux ratios to obtain close agreement with the measurements.

Kinetics and mechanism of dehydration of isopropyl and sec-butyl alcohols on catalysts consisting of quartz coated by liquid phosphoric acid and mixtures of phosphoric acid and KH2PO4

1. A pulsed Chromatographie method was used to investigate the kinetics and mechanism of dehydration of isopropyl alcohol on catalysts consisting of fused quartz coated with phosphoric acid and phosphoric acid with potassium dihydrophosphate. 2. Data on the dehydration of sec-butanol on a catalyst consisting of quartz coated with phosphoric acid have been checked and their precision improved. 3. In the experiments with catalysts without the addition of salt, the rate constant of the dehydration of secondary propyl and butyl alcohols increases proportionally to the square of the thermodynamic activity of the acid when the concentration of the phosphoric acid in the liquid phase is changed. This fact is attributed to the participation of the nonionized alcohol molecule and two molecules of phosphoric acid in the limiting stage of the reaction.