Butanol In Water Research Articles

Hydrogenation of Furfural to Cyclopentanone in Tert–Butanol-Water Medium: A Study of the Reaction Intermediates Reactivity Using Cu/ZnO/Al2O3 as Catalyst

The catalytic transformation of furfural to cyclopentanone has been investigated using two different liquid phases as solvent: water and 30 wt.% tert–butanol in water. When using neat water at 160 °C, 40 bar of H2, and after 2 h of reaction time, furfural polymerizes, and the yield of cyclopentanone is just 42% with a low carbon balance, indicating that furfural is transformed to non-detected by-products, likely heavy resins. When using 30 wt.% tert–butanol in water, the yield of cyclopentanone is ca. 20%, and the major product is furfuryl alcohol with a 47% yield. We have studied the catalytic transformation of the most relevant reaction intermediates in the overall conversion of furfural to cyclopentanone. In the presence of tert–butanol, two steps are inhibited in the overall pathway: (i) the Piancatelli rearrangement of furfuryl alcohol and (ii) the transformation of cyclopentenone. This inhibition is attributed to the neutralization of protons from water dissociation by surface sites on the catalyst, preventing their participation in the overall reaction. To counteract these inhibitions when tert–butanol is present, higher H2 pressure (60 bar) and temperatures (200 °C) are required. We have been able to obtain productivities per gram of catalyst and mols of Cu basis of 411 gprod·h−1·gcat−1 and 14 gprod·s−1·molCu−1, respectively, which is substantially above that found for other copper-based catalysts.

Carbon nanotube enhanced selective micro filtration of butanol

In this study, we present the development of a carbon nanotube (CNT), immobilized membrane (CNIM) via a phase inversion process for dewatering butanol via microfiltration. The CNTs enhanced membrane hydrophobicity and butanol permeation via adsorption on the CNTs surface leading to relatively high levels of preconcentration, which was not possible using a plain PTFE membrane. The CNIM exhibited a water contact angle of 136 ± 2°, indicating high hydrophobicity. The contact angle decreased with an increase in butanol concentration due to the strong interaction of the CNTs with the latter. The water-butanol mixtures behaved differently at different concentration zones namely water in butanol, WIB (over 80 percent butanol), butanol in water, BIW (below 30 percent butanol), and butanol-water colloidal mixtures, BWCM (30 to 70 percent butanol). At low or high concentrations of butanol, the butanol was strongly hydrogen bonded with the water, and the separation efficiency was relatively lower, between 6.50 and 15.54 % in the WIB and 1.00 to 3.05 % in the BIW regions. In the BWCM regions, water butanol formed colloidal mixtures the separation efficiency was significantly higher. At a feed butanol concentration of 40 %, the water separation reached as high as 43.40 %, with a flux of 118.08 kg/(m2h). The high separation efficiency was attributed to the influence of well-dispersed CNTs on the CNIM which provided sites for the agglomeration of nano water droplets into larger ones that could be removed more easily, as well as the high partition coefficient of the butanol on the CNIM surface.

Study of the evaporation kinetics of pure and binary droplets: volatility effect

This work presents a study on the evaporation of a volatile liquid droplet placed on a substrate and surrounded by air. We consider in this work the case of a pure liquid droplet (water, ethanol and butanol), and the case of a binary mixture droplet (water-ethanol and water-butanol). The aim of this work is to study the effect of the volatility of each component within a pure or binary droplet on the evaporation kinetics. The volatility of a liquid is considered as the ability of a substance to evaporate. One liquid is more volatile than another is the one with the lowest boiling temperature. We noticed that for pure liquid droplets, the volatility of the liquid considerably influences its life and cooling effect. After evaporation, the more volatile the liquid, the shorter the life of the droplet and the greater its cooling. The results of the simulation were compared and validated by the literature. Experimental results are used for validation and interpretation of the evaporation of water-butanol binary droplet. The behavior of the butanol in the mixture is different to that when it is pure. Despite its low volatility compared to water, strongly diluted in a water-based droplet, butanol evaporates in a preferential way. In fact, in the diluted mixture, the fraction of butanol evaporates first and is exhausted before that of water. The binary droplet tends to become a pure water droplet. We also show that, the same as in the case of the water-ethanol, the addition of butanol in water accelerates evaporation and decreases the droplet’s life.

Volumetric Properties of Secondary Butanol and Tertiary Butanol in Water and Aqueous Micellar Systems of Sodium Dodecyl Sulphate

The apparent molal volumes of sec-butanol and t-butanol in water and in aqueous micellar system of sodium dodecyl sulphate have been determined from density measurements at different surfactant concentrations and temperatures. The partial molal volumes of the alcohols in aqueous micellar system at infinite dilution, V20 (mean, mic) were obtained from apparent molal volume data and compared with the corresponding values in aqueous solvent, V20 (mean, aq). The standard partial molal expansibilities, E20 (mean) of the alcohols were evaluated from V20 (mean) data at various temperatures. The transfer apparent molal volumes, ∆φtr0 for the alcohols from water to surfactant-water system are determined from apparent molal volume data. The sign and magnitude of these parameters are used to analyze the location of the solubilizate (alcohols) in the micellar system and the nature of interactions between alcohols and the micellar aggregates.

Analysis of gentisic acid and related renal cell carcinoma biomarkers using reversed-phase liquid chromatography with water-rich mobile phases

The problem of longer retention times using water-rich mobile phases in reversed-phase liquid chromatography (RPLC) has been addressed using hydrophobic alcohols such as butanol in very low quantities (approximately 0.1%) as the organic modifier. Advantages of water-rich mobile phases in RPLC for the separation of water-soluble and weakly retained compounds are improved separation of congeners and better tuning of RPLC separations. This is demonstrated in the separation of gentisic acid and related renal cell carcinoma (RCC) biomarkers in urine with a Zorbax C18 column and a mobile phase of 0.1% (volume/volume) butanol in water with 0.6% (volume/volume) acetic acid. Calibration curves for the RCC biomarkers were linear over the concentration range investigated (5–1000 ppm). Detection limits for the RCC biomarkers were 0.85 ppm (quinolinic acid), 1.75 ppm (gentisic acid), and 1.25 ppm (4-hydroxybenzoic acid). Recovery tests using synthetic urine samples containing 20 ppm, 100 ppm, and 700 pm of each RCC biomarker were successful for all compounds.

Study of self-rewetting fluid applied to loop heat pipe with PTFE wick

It’s the first using self-rewetting fluid with PTFE wick structure applied to Loop Heat Pipe System. PTFE wick structure has low thermal conductivity, low sintering temperature thus low cost and high anti-oxidation production for long term using which can also overcome heat leakage when operating. It effectively improves the performance of traditional metal wick structure. However, with the hydrophobic of PTFE material, we can’t directly use water as working fluid. Therefore, this paper adds butanol in water to form self-rewetting fluid which not only easily goes through PTFE wick structure but spontaneously supplements the heating surface, making system operates successfully.After testing the surface tension and heat-transfer performances of LHP system, it shows that LHP system begins to work by adding 3wt% butanol aqueous solution. It has the maximum heat capacity of 400W, the minimum thermal resistance 0.32°C/W and heat flux 20W/cm2 when increasing to 6wt% butanol aqueous solution. It’s also the first point making LHP system operate successfully. Compared to the water-nickel system, butanol-PTFE system halving the total thermal resistance, heat flux increases over 50%, and the lower operating temperature and pressure, thus it can have higher stability and security.

Direct self-condensation of bio-alcohols in the aqueous phase

Recyclable iridium catalysts have been developed rationally for the direct self-condensation of ethanol and butanol in water and air.

Analysis of vanilla extract by reversed phase liquid chromatography using water rich mobile phases

Vanillin is the major constituent of vanilla extract, a flavoring ingredient used in food and beverages. Natural vanilla extract prepared from the bean of the tropical orchid, Vanilla planifolia, is expensive due to the limited supply of the vanilla bean. For this reason, synthetic vanilla extracts are widely used. Synthetic vanilla extracts are less complex and usually contain vanillin, ethyl vanillin, and other related compounds that are prepared from inexpensive starting materials. Several liquid chromatographic methods have been developed to quantitate coumarin, vanillin, and ethyl vanillin in vanilla extract. The use of water rich mobile phases in reversed phase liquid chromatography (RPLC), e.g., 1% butanol in water with 0.2% acetic acid with C18, C8, and cyanopropyl columns, has been investigated as a potential method to characterize the composition of synthetic vanilla extracts. Better resolution is achieved in the separation of vanillin compounds when hydrophobic alcohols are used as organic modifiers. This can be attributed to butanol partitioning into the bonded phase, which provides a more extended ordered surface increasing the contact surface area of the stationary phase and thereby increasing the selectivity of the separation. Using water rich mobile phases, constituents of vanilla extract in 36 commercial products obtained from stores in the local area were identified demonstrating the efficacy of the proposed RPLC method.

A theoretical study of the dehydration of tertiary butanol in near-critical and supercritical water

Molecular dynamics simulations were performed to investigate the dehydration of tertiary butanol in water under ambient, near-critical and supercritical conditions. It was found that the equilibrium constant increased with temperature at a fixed pressure of 400 bar, favouring the dehydration reaction. This was mainly due to an increase in the entropy of reaction. The equilibrium was also favoured by low pressures. Studies of the solvation of isobutene gave an insight into how the hydrophobic effect varies with the state point of the water. It was seen that the solvation of isobutene becomes more favourable at higher temperatures due to the increasing entropy of solvation.

Effects of molecular size and chain profile of waxy cereal amylopectins on paste rheology during retrogradation

Amylopectins were purified from five waxy cereal starches (corn, sorghum, barley, wheat, and rice) in amorphous state by ethanol precipitation from dimethyl-sulfoxide (DMSO) solution followed by removing any amylose complexes with butanol in water. Their molecular weights ( M w) were determined by size-exclusion chromatography in tandem with multi-angle laser light scattering and refractive index detectors. Chain length distributions were determined by debranching followed by size-exclusion chromatography coupled with a refractive index detector. Amylopectin pastes (15% dry solids) were also analyzed using a dynamic rheometer while cooling to 4 °C and storing for 20 days, and the relations between the structural and rheological characteristics were investigated. The weight-average molecular weights ( M w) of the waxy cereal amylopectins ranged from 204.4 × 10 6 to 344.4 × 10 6 g/mol, and the average chain length (CL w) ranged from 26.8 to 30.4. Among the tested starches, waxy rice had the largest amylopectin molecules and the longest B ⩾ 2 chains. The order of chain length of B ⩾ 2 chains among the samples were waxy rice > waxy corn = waxy sorghum > waxy barley = waxy wheat. But there were no difference in the CL w of total chains among the amylopectins. Storage ( G′) and loss ( G″) moduli of amylopectin pastes (15% solids) significantly increased during the cooling period from 95 to 4 °C, which was more than the increase during cold storage for 20 days at 4 °C. Among the waxy samples, waxy rice displayed the greatest moduli increases both during the initial cooling and during the cold storage. Among the structural parameters measured, the M w of amylopectin and CL w of B ⩾ 2 chains correlated positively with complex modulus( G ∗) increases.

Effect of different sodium halides on the self-association of tertiary butanol in water

The molecular self-association of hydrophobic substances is an important process for many biological systems. Here, the authors study the effect of salt on the molecular self-association of t-butanol in water solution, using NMR techniques. They compare the effects of different sodium halides (NaCl, NaBr, and NaI) as a function of their concentration.

Structure and interactions in simple solutions

Neutron scattering with hydrogen/deuterium isotopic substitution techniques has been used to investigate the full range of structural interactions in a dilute 0.02 mol fraction solution of tertiary butanol in water, both in the absence and in the presence of a small amount of sodium chloride. Emphasis is given to the detailed pictures of the intermolecular interactions that have been derived using the empirical potential structure refinement technique. Analysis has been performed to the level of the spatial density distribution functions that illustrate the orientational dependence of the intermolecular interactions between all combinations of molecular and ionic components. The results show the key structural motifs involved in the interactions between the various components in a complex aqueous system. They underline the structural versatility of the water molecule in accommodating a range of different kinds of interactions while retaining its characteristic first-neighbour interaction geometry. Within this framework, the results highlight the complex interplay between the polar, non-polar and charged molecular interactions that exist in the system.

Determination of the In-Solution Molecular Structure of Reactive Osmium Compounds Involved in the Synthesis of Vicinal Diols

Extended X-ray absorption fine structure spectroscopy, EXAFS, has been used to determine the in-solution structure of the two principal reactive components involved in the production of vicinal diols by olefin dihydroxylation using osmium tetroxide. These components are osmium tetroxide (OsO4) and the corresponding diester osmium glycolate complex. The results show that initially the osmium tetroxide molecules are found free and unbound in the investigated solvent (6:1 tertiary butanol in water), with a molecular structure close to that found in the solid state. On addition of an excess of 2,3-dimethyl-2-butene, a compound of formula OsO(O2C6H12)2, a monomeric diester of osmium tetroxide, is formed. The structural refinement of this compound indicates that the osmium center is surrounded by five oxygen atoms, one located at a shorter distance than the other four (1.69 and 1.90 Å, respectively). The same structure has been found for the osmium complex formed as the result of the slow reaction of osmium tetroxide with an excess of ethylene glycol in solution, OsO(O2C2H4)2. This last complex is compared with the known solid state structure.

Structural correlations of water molecules in a concentrated alcohol solution

Hydrogen/deuterium isotopic substitution neutron scattering techniques andempirical potential structure refinement have been used to investigate thestructure in a 0.86 mole fraction solution of tertiary butanol in water. Theresulting model structure suggests that in this mixture, the relatively smallquantity of water molecules tend to associate in small hydrogen bonded clusters oftwo or three molecules, solvated by the alcohol hydroxyl groups. An interestingobservation on investigating this novel local water environment is that thetetrahedral hydrogen bonding motif of water still strongly influences thelocation of both the water and alcohol first neighbours. The combinationof the small number of water molecules in the mixture and the bulkymolecular structure of the alcohol appears to result in the incompletesatisfaction of the water molecule’s full hydrogen bonding capabilities.

The structure of a concentrated aqueous solution of tertiary butanol: Water pockets and resulting perturbations

The structure of a 0.86 mole fraction solution of tertiary butanol in water at room temperature has been investigated by neutron diffraction with hydrogen/deuterium isotope substitution. The intermolecular correlations between the alcohol and water molecules have been extracted using the empirical potential structure refinement technique. The results highlight the creation of water pockets within the solution structure. These pockets mediate the interactions that occur between the alcohol hydroxyl groups, reducing the level of direct alcohol–alcohol hydrogen bonding. The results show that only a small amount of water is required to drive this solution in the direction of hydrophobic behavior more commonly associated with the water-rich solution compositions.

Temperature dependence of the structure of a 0.06 mole fraction tertiary butanol-water solution

Hydrogen/deuterium isotopic substitution neutron diffraction techniques have been used to measure the solute–solute, solute–solvent and solvent–solvent structural correlation functions in a 0.06 mole fraction solution of tertiary butanol in water. The measurements were made at two temperatures, 25 °C and 65 °C. Data analysis to the level of intermolecular orientational correlation functions was performed by the Empirical Potential Structure Refinement (EPSR) technique in combination with a spherical harmonic coefficient analysis. The results reveal in particular a subtle temperature dependence of the intermolecular structure of the solvent water. This structural perturbation is suggestive of a hydrophobic hydration induced, local density enhancement in the solvent water that could relate to the entropic driving force underlying the hydrophobic interaction mechanism.

Decomposition of t-Butanol in Water by γ-Irradiation Combined with Ozone; Cupric Ion Effect

Abstract When t-butanol in aqueous system was decomposed by simultaneous application of γ-rays and ozone treatment, the addition of the cupric ion (Cu2+) drastically improved the efficiency of the removal of organic substances from water. The major reason for the remarkable decrement of total organic substances is the positive catalytic effect of Cu2+ on the oxidation of carboxylic acids.

Calorimetric study on the solubilization of butanol by alkylphosphate and alkylphosphate-lecithin systems.

Microcalorimetric studies on alkylphosphate-butanol and alkylphosphate-butanol-lecithin systems were carried out as a first step to study the role of butanol (used as cosurfactant) in the formation of microemulsions. The enthalpy of solubilization; delta H, of the same amount of butanol (1.806 mol kg-1) in aqueous sodium monoalkyl-phosphates, with a hydrocarbon chain varying from 6 to 10 carbon atoms, was investigated as a function of alkylphosphate concentration. Measurements were performed in the presence and in the absence of lecithin. The enthalpy values measured upon addition of butanol to the mixtures were negative in all cases. Below the critical micelle concentration (CMC) of the alkylphosphates, the heats of butanol dissolution were found to decrease upon increasing the concentration of the alkylphosphate. This behaviour was related to the dissolution of butanol in water and to the formation of mixed butanol-alkylphosphate and butanol-alkylphosphate-lecithin micelles. Above the CMC essentially constant delta H values were found. The delta H measured may be the sum of simultaneous effects--heat of alcohol dissolution and the simple alkylphosphate micelle dissociation or alkylphosphate-lecithin mixed aggregate dissociation and the heat of mixed micelle formation. The delta H at the plateaus were linearly related to the corresponding CMC values of the alkylphosphates.

Solubility of polychlorinated biphenyls in binary water/organic solvent systems

Solubilities of four polychlorinated biphenyls (PCBs), 4-chlorobiphenyl, 2,4,6-trichlorobiphenyl, 2,3,4,5-tetrachlorobiphenyl and 2,2′,4,4′,6,6′-hexachlorobiphenyl, were determined in pure water and in several water/organic solvent (methanol, butanol, octanol, benzyl alcohol and benzene) systems using a generator column technique. A batch equilibrium method was also used to ensure that result from the two techniques were comparable. The presence of methanol and butanol in water enhanced the solubility of all four PCB congeners, the degree of the enhancement increasing with both cosolvent concentration and hydrophobicity of the PCB solutes. Dissolved octanol and benzene, at a concentration near saturation in water, reduced the solubility of the PCBs, with a larger reduction observed for the more hydrophobic PCB congeners. The effects of dissolved benzyl alcohol on the aqueous solubility of the four PCB congeners varied with the benzyl alcohol concentration and the individual PCB congener.