Alcohol Molecules Research Articles

Simulation of gas chromatographic separation based on random diffusion

色谱分离过程中的粒子扩散问题是色谱动力学研究的基础,深入理解粒子的扩散行为对优化分离操作条件、提升色谱性能和开发新型色谱柱尤为关键。现有的模拟方法多集中于局部过程的热力学研究,而整体的扩散分离过程报道并不多见。为此,该文基于微尺度受限空间内随机扩散的方法,通过动态追踪粒子的运动轨迹,实现粒子在气相色谱开管柱内的扩散全过程模拟。基于前期烷烃同系物的分离模拟研究,结合Kovats保留指数,分别建立了吸附步数与温度、吸附步数与碳数的函数关系,由此获得不同类型的同系物在不同温度条件下的分离参数系统。以醇类同系物的分离验证模拟的可靠性,结果表明保留时间的相对误差基本控制在5%以内,而峰宽相对误差在0.75%~60%之间。峰宽误差较大的原因在于:(1)参数化计算过程中未能充分迭代以及使用外推法;(2)模型中忽略了醇分子之间的氢键作用。该文提出的模拟方法虽然可以准确地预测色谱保留时间以及合理描述色谱峰的基本形貌特征,但尚有进一步发展空间,特别是增加对分子间相互作用的细节处理,例如可参考分子力学的方法建立分子间势函数和吸附步数的关系,利用分子力学计算的能量来取代参数化的吸附步数,从而实现更为精确的分离过程模拟。总体而言,该文所提出的模拟方法为优化色谱分离操作条件和开发新型色谱分离技术提供了有价值的参考。

Enhancement of performance and stability of thin-film nanocomposite membranes for organic solvent nanofiltration using hypercrosslinked polymer additives

Hypercrosslinked polymer (HCP) additives were successfully incorporated into two polymer matrices: glassy polymer with intrinsic microporosity comprising ethanoanthracene and Tröger's base (PIM-EA-TB) as well as rubbery polydimethylsiloxane (PDMS), forming thin-film nanocomposite (TFN) membranes for organic solvent nanofiltration (OSN) applications. The thermal stability and surface morphology of TFN membranes were characterized by TGA and SEM. OSN results showed that HCP additives increased the alcohol permeances for both kinds of membranes as it provided extra pathways for alcohol molecules to transport through the membranes. Particularly, the PIM-EA-TB membrane gained above 32% improvement on methanol and ethanol permeances after loading of 5 wt% HCP, whilst maintaining a rejection of 92% for Rose Bengal. Moreover, the physical aging of PIM-EA-TB membrane was retarded by HCP additives and the swelling of the PDMS membrane in non-polar solvents was reduced. In small quantities, the HCP nanoparticles proved to be effective additives to improve the OSN performances for both glassy and rubbery polymer membranes. • Hypercrosslinked polymers (HCPs) were incorporated into glassy and rubbery polymer matrices. • HCPs enhanced the separation performances of polymer membranes during organic solvent nanofiltration. • HCPs mitigated physical aging in glassy polymers and swelling of rubbery polymers. • Interaction mechanisms between HCPs and polymer chains at the interface were proposed.

Phase equilibrium and ionic liquid partitioning in aqueous two-phase system composed of alcohol and small molecule compound

Phase equilibrium and ionic liquid partitioning in aqueous two-phase system composed of alcohol and small molecule compound

Alcohol Selective Optical Sensor Based on Porous Cholesteric Liquid Crystal Polymer Networks.

A responsive hydrogen-bonded cholesteric liquid crystal polymer (CLCP) film with controlled porosity was fabricated as an optical sensor to distinguish between methanol and ethanol in alcohol solutions. To facilitate responding the alcohols, porosity was generated by removing the nonreactive liquid crystal agent, and the hydrogen bridges of CLCP were broken. The sensitivities of CLCPs to ethanol and methanol were obtained by monitoring the wavelength shifts of the transmission spectrum at different alcohol concentrations and ratios of methanol/ethanol. Changes in the central wavelength of the CLCP network transmission spectrum allowed the methanol–ethanol ratio to be discriminated. A linear relationship between wavelength shift of CLCP networks and alcohol concentration was obtained experimentally, and the sensor characteristics were explored. The sensitivities of the CLCPs were 1.35 and 0.18 nm/% to ethanol and methanol, respectively. The sensing sensitivity of cholesteric networks to alcohol molecules increased as the methanol–ethanol ratio declined. Therefore, CLCP could act as a stimuli-responsive material to distinguish the concentrations of acetone and ethanol in mixed solutions. Furthermore, the impact of UV intensity for curing a CLC mixture on the sensing sensitivity to the different alcohol concentrations was also studied. The higher UV intensity could enhance the sensitivity to alcohol molecules and distinguishing ability between methanol and ethanol.

Unravelling Anion Solvation in Water‐Alcohol Mixtures by Single Entity Electrochemistry

AbstractSingle entity electrochemistry is employed to gain insights into ion solvation in solvent mixtures. To this end, the time required for the oxidation of individual indicator nanoparticles to sparingly soluble products is used to probe ionic diffusion, and hence gain new insights into the solvation properties of solvent mixtures. Herein, water‐ethanol or water‐methanol mixtures of different compositions are analyzed following this new approach, using silver nanoparticle oxidation in the presence of chloride and iodide as a complementary indicator reaction. For increasing concentrations of the bulkier alcohol molecules in the mixtures with water, an increasing content of alcohol molecules in the halide's solvation shell is detected by the observation of hindered halide diffusion. The extent of this solvent replacement is shown to scale with the charge density of the ions and the experimental results are rationalized with respect to literature‐derived thermodynamic data, highlighting the ability of single entity electrochemistry to explore solvation in solvent mixtures.

Vibrational Strong Coupling between Surface Phonon Polaritons and Organic Molecules via Single Quartz Micropillars.

Vibrational strong coupling (VSC), the strong coupling between optical resonances and the dipolar absorption of molecular vibrations at mid-infrared frequencies, holds the great potential for the development of ultrasensitive infrared spectroscopy, the modification of chemical properties of molecules, and the control of chemical reactions. In the realm of ultracompact VSC, there is a need to scale down the size of mid-infrared optical resonators and to elevate their optical field strength. Herein, by using single quartz micropillars as mid-infrared optical resonators, the strong coupling is demonstrated between surface phonon polariton (SPhP) resonances and molecular vibrations from far-field observation. The single quartz micropillars support sharp SPhP resonances with an ultrasmall mode volume, which strongly couples with the molecular vibrations of 4-nitrobenzyl alcohol (C7 H7 NO3 ) molecules featuring pronounced mode splitting and anticrossing dispersion. The coupling strength depends on the molecular concentration and reaches the strong coupling regime with only 7300 molecules. The findings pave the way for promoting the VSC sensitivity, miniaturing the VSC devices, and will boost the development of ultracompact mid-infrared spectroscopy and chemical reaction control devices.

Metal-Free Transparent Three-Dimensional Flexible Electronics by Selective Molecular Bridges.

Flexible and transparent electronics is a new generation of device enabling modern interactive designs, which facilitates the recent development of low-cost, lightweight, and flexible materials. Although conventional indium tin oxide material still dominates the major market, its brittleness and steadily increasing price drive scientists to search for other alternatives. To meet the high demand, numerous metallic or organic conductive materials have been developed, but their poor adhesion toward supporting substrates and the subsequent circuit patterning approach remains problematic. In this study, a robust metal-free flexible conductive film fabrication strategy is introduced. The flexible polyethylene terephthalate (PET) film is utilized as the base, where a poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) conductive layer is tightly linked onto this supporting substrate. An interface activation process, i.e., oxygen plasma treatment, generates PET surface active spots to react with the subsequently introduced poly(vinyl alcohol) (PVA) molecule functional groups. This spatially selective PVA molecular bridge therefore acts as a dual-function intermediate layer through covalent bonding toward PET and hydrogen bonding toward PEDOT:PSS to conjugate two distinct materials. This PEDOT:PSS/PVA/PET film delivers superior physical properties, such as a high conductivity of 38.2 Ω/sq and great optical transmittance of 84.1%, which are well tunable under conductive polymer thickness controls. The film is also durable and can maintain original electrical properties even under serious bending for hundreds of cycles. Relying on these outstanding performances, arbitrary conductive circuits are built on this flexible substrate and can function as normal electronics when integrated with multiple electronic parts, e.g., light-emitting diodes (LEDs). Superior electrical signal outputs are achieved when complicated stereo structures including folding, splicing, interlacing, and braiding are incorporated, enabling the use of these films for flexible three-dimensional electronics assembling. Space identifying smart key and lock pair, origami rabbit-carrot touch response, pressure-stimulated jumping frog, and moving dinosaur recognition designs realize these PEDOT:PSS/PVA/PET film-based human-machine interactive devices. This flexible, transparent, and conductive film generation approach by molecular bridge creation should facilitate future development of flexible or foldable devices with complex circuits.

Ni@C@CNT catalyst derived from CNT doped Ni‐MOF for furfural hydrogenation to tetrahydrofurfuryl alcohol

AbstractConversion of biomass‐derived furfural platform compound to value‐added tetrahydrofurfuryl alcohol (THFL) molecule is a sustainable route, and an efficient nonnoble metallic catalyst is a key factor for this reaction. In this work, Ni@C@CNT composite as a highly effective catalyst for hydrogenation of furfural to tetrahydrofurfuryl alcohol was synthesized by one‐step pyrolysis of Ni‐centered metal organic framework (Ni‐MOF) doping with carbon nanotube (CNT). For comparison, Ni@C catalyst derived directly from Ni‐MOF was also synthesized. The characterization results show that the doping of CNT promotes high dispersion of active sites and formation of Ni3C phase which has Pt‐like catalytic activity. Therefore, the obtained Ni@C@CNT exhibited excellent activity in furfural hydrogenation (99.1% furfural conversion and 94.7% THFL yield at 120°C, 4 h, 4‐MPa initial hydrogen pressure). Ni@C@CNT also shows good stability in reuse test. Current work presents a facile method for preparation of nonnoble metallic catalysts with high efficiency.

Physicochemical and statistical characterization of gas-sensing behaviors of resonator sensors with carbonaceous films prepared by rf-sputtering of aromatic and hydrophilic biomolecules

Quartz crystal resonators coated with gas-sorptive films were characterized by analyzing their structures and their organic gas-sorption behaviors, which were then studied using statistics and computational molecular simulations. The films had carbonaceous structures that were prepared by radio-frequency (rf) sputtering of aromatic biomolecules, such as cytosine and lignin. These films had been compared with the rf-sputtered films of hydrophilic biopolymer of lignin and gelatin.The composition and morphology of each film governed the organic gas-sorption characteristics of the resonator sensors used for organic gas-sensing. The cytosine film, which was nitrogen-rich and layered, had a moderate affinity for the larger molecules of normal alcohols and acetate esters. The cytosine film is repulsive to positively-charged moieties of adsorbates. In contrast, the agarose film, which was nitrogen-poor and columnar, had a high affinity for small adsorbates with short hydrocarbon chains. Molecular flexibility of the adsorbate played an important role in the gas-sorption ability of the agarose film. Molecular dynamics simulation clarified that the weakly dipolar adsorbate-aggregate were immiscible in the cytosine adsorbent-aggregate because the collision mixture was prone to be instable. In practice, the cytosine-sputtered film had a higher gas-sorption ability for weakly dipolar species that have the longer hydrocarbon chains.

Homostructured graphene oxide-graphene quantum dots nanocomposite-based membranes with tunable interlayer spacing for the purification of butanol

The successful tuning of the GO interlayer space was possible by using OGQDs. The integration of OGQDs was also found to improve the separation efficiency by blocking the transport of alcohol molecules and allows the faster transport of water molecules. • A homostructured selective layer from GO and OGQDs was made. • The GO interlayer space was tuned by using OGQDs. • The separation of butanol/water mixture was augmented by OGQD integration. • The altered transport channels blocked the n -butanol molecules to permeate. The two-dimensional graphene oxide (GO) shares similar structure and functional groups with the zero-dimensional oxygen-passivated graphene quantum dots (OGQDs) but differs in size. Herein, homostructured membranes with GO and OGQDs were prepared through the pressure-assisted self-assembly method. The OGQDs loading were varied to adjust the interlayer spacing between GO nanosheets. The fabricated GO-OGQDs composite membranes were characterized accordingly to identify the interactions between the two carbon-based nanomaterials and its effect on the pervaporative dehydration of n -butanol. A stable nanocomposite lamella was achieved through π-π interactions and hydrogen bonding. The membranes showed an excellent performance in pervaporation of 90/10 wt% n -butanol/water mixture at 25 °C. The pristine GO and GO-OGQD 100 composite membranes resulted in a total flux of 760 gm -2 h −1 and 945 gm -2 h −1 , respectively. At 100 ppm OGQD loading, the composite membrane also resulted with a high-water concentration in permeate of 99.99 wt%. The augmented performance was due to the alteration of the hydrophilic transport channels on GO by OGQD integration. This helped to increase the water flux and blocks the n -butanol molecules to permeate. The GO-OGQD 100 composite membrane provides good performance even in long-term operation. The results herein provide an understanding in preparing nanocomposite materials with similar chemical structures that differ in size. Furthermore, the successful purification of butanol could be done through an environmentally friendly membrane separation process.

Low-temperature ALD/MLD growth of alucone and zincone thin films from non-pyrophoric precursors.

The combined atomic/molecular layer deposition (ALD/MLD) technique is emerging as a state-of-the-art synthesis route for new metal-organic thin-film materials with a multitude of properties by combining those of the inorganic and the organic material. A major part of the studies so far reported have focused on aluminum or zinc alkyls, so-called alucone and zincone films, typically grown from trimethyl aluminum (TMA) or diethyl zinc (DEZ) as the metal-bearing precursor, and a simple aliphatic bi-functional alcohol molecule such as ethylene glycol (EG) as the organic precursor. However, these common precursors possess certain disadvantages: both TMA and DEZ are pyrophoric, DEZ being additionally thermally unstable, while EG has a strong tendency for various unideal reaction modes. Here we report novel ALD/MLD processes for alucone and zincone films based on non-pyrophoric bis-diisopropylamido-[3-(N,N-dimethylamino)propyl] aluminum(III) [Al(NiPr2)2(DMP)] and bis-3-(N,N-dimethylamino)propyl zinc(II) [Zn(DMP)2] precursors in combination with hydroquinone (HQ) as the organic precursor. We demonstrate that the [Al(NiPr2)2(DMP)] + HQ and [Zn(DMP)2] + HQ ALD/MLD processes work even at record low deposition temperatures (140 °C and 60 °C, respectively) yielding high-quality and relatively stable Al-HQ and Zn-HQ thin films with appreciably high growth rates (2.8 Å / cycle and 3.2 Å / cycle, respectively). Moreover, these ALD/MLD processes are compatible with the corresponding ALD processes, i.e. [Al(NiPr2)2(DMP)] + H2O and [Zn(DMP)2] + H2O, for the Al2O3 and ZnO films, thus opening up new horizons for the fabrication of novel metal-oxide : organic superlattice structures for e.g. flexible gas-barrier coatings or wearable thermoelectrics.

Chromone-methanol clusters in the electronic ground and lowest triplet state: a delicate interplay of non-covalent interactions.

Chromone offers two energetically almost equivalent docking sites for alcohol molecules, in which the hydroxyl group is hydrogen bonded to one of the free electron pairs of the carbonyl O atom. Here, the delicate balance between these two competing arrangements is studied by combining IR/R2PI and UV/IR/UV spectroscopy in a molecular beam supported by quantum-chemical calculations. Most interestingly, chromone undergoes an efficient intersystem crossing into the triplet manifold upon electronic excitation, so that the studies on aromatic molecule-solvent complexes are for the first time extended to such a cluster in a triplet state. As the lowest triplet state (T1) is of ground state character, powerful energy decomposition approaches such as symmetry-adapted perturbation theory (SAPT) and local energy decomposition using the domain-based local pair natural orbital coupled-cluster method (DLPNO-CCSD(T)/LED) are applied. From the theoretical analysis we infer for the T1 state a loss of planarity (puckering) of the 4-pyrone ring of the chromone unit, which considerably affects the interplay between different types of non-covalent interactions at the two possible binding sites.

Structural diversity and magnetic properties of copper(ii) quinaldinate compounds with amino alcohols

Copper(ii)–quinaldinate-amino alcohol reaction systems produced structurally diverse compounds with amino alcohol molecules or their deprotonated forms serving as ligands.

Thermal Analysis of Plastics Used in the Food Industry.

Fires in landfills, where used plastic packaging waste is discarded, have shown how great a fire hazard these types of materials pose. In this study, the course of thermo-oxidation of samples made of polypropylene (PP), polystyrene (PS), and polyethylene terephthalate (PET) based plastics was determined. Based on an analysis of the dissociation energy of bonds between atoms in a polymer molecule, the mechanisms responsible for the character and course of degradation were observed. It was found that the degradation rate of PP and PS could be a result of the stability of C-H bonds on the tertiary carbon atom. In the case of PS, due to facilitated intramolecular hydrogen transfer, stabilization of hydroperoxide, and formation of a stable tertiary alcohol molecule, the onset of degradation is shifted towards higher temperatures than in the case of PP. Notably, the PP fragmentation occurs to a greater extent due to the easier course of β-scission. In addition, it was found that during a fire, the least amount of heat would be generated by thermo-oxidation of PS-based plastics. This is a result of the formation of a styrene molecule during decomposition that, due to the high stability of bonds in the aromatic ring, escapes from the combustion zone without oxidation. It has been proven that the greatest thermal effect accompanies PET decomposition, during which a phenyl radical is produced, where the C-H bonds break more easily in comparison with the bonds of an intact ring.

Effect of temperature on the reverse self-assembly of lecithin and sugar alcohol mixtures in a nonpolar solvent

It has been shown that the addition of sugar alcohols to lecithin solutions induces a transformation from reverse spherical micelles into reverse cylindrical micelles, resulting in the formation of viscoelastic Maxwell fluids. Herein, we systematically investigated the effects of temperature on the rheological parameters, such as the plateau modulus (Gp), relaxation time (tR), and zero-shear viscosity (η0), of lecithin and sugar alcohol mixtures in decane. The rheological properties upon heating of mixtures of lecithin and sugar alcohols with different numbers (3–6) of hydroxyl (–OH) groups and concentrations were studied in detail. Gp, tR, and η0 for all reverse cylindrical micelles decreased with temperature. This decrease can be attributed to a reduction in the lengths of the reverse cylindrical micelles, as evidenced by the small-angle X-ray scattering results at different temperatures. More importantly, the decay rates of Gp, tR, and η0 upon heating decreased more rapidly when the hydrogen bonds between the lecithin and sugar alcohol molecules were weaker as the hydrogen bonds were closely associated with the formation of the reverse self-assembled structure. This indicates that the driving force for the formation of reverse cylindrical micelles can be weakened by increasing the temperature.

Mechanistic Studies on the Base-Promoted Ring Opening of Glycal-Derived gem-Dibromocyclopropanes.

In the presence of a nucleophilic base, ring-fused gem-dibromocyclopropanes derived from d-glycals undergo ring opening to give 2-deoxy-2-(E-bromomethylene)glycosides. Such cleavage of an exocyclic cyclopropane bond contrasts with the more usual silver-promoted ring-expansion reactions in which endocyclic bond cleavage occurs. Experimental and theoretical studies are reported which provide insights into the reaction mechanism and the origin of its kinetic selectivity for E-configured bromoalkene products. Density functional theory computations (M06-2X) predict that the reaction commences with alkoxide-induced HBr elimination from the dibromocyclopropane to form a bromocyclopropene. Ring opening then gives a configurationally stable zwitterionic (oxocarbenium cation/vinyl carbanion) intermediate, which undergoes nucleophilic addition and protonation to give the bromoalkene. There are two competing sources of the proton in the final step: One is the alcohol (co)solvent, and the other is the molecule of alcohol produced during the initial deprotonation step. The roles of the formed alcohol molecule and the bulk (co)solvent are demonstrated by isotope-labeling studies performed with deuterated solvents. The acid-promoted isomerization of the E-bromoalkene product into the corresponding Z-bromoalkene is also described. The mechanistic knowledge gained in this investigation sheds light on the unusual chemistry of this system and facilitates its future application in new settings.

Temperature effects on alcohol aggregation phenomena and phase behavior in n-butanol aqueous solution

Liquid-liquid phase separation is an important phenomenon that prevails from simple to complex molecular systems where temperature plays a crucial role in the fundamental understanding of phase behavior in a theoretical and industrial perspective. The n-butanol aqueous solutions have two separate liquid phases of alcohol-rich and water-rich formed at room temperature. The change in phase behavior occurs from two phases to one with an increase of temperature, exhibiting an upper critical solution temperature (UCST) behavior. We carried out molecular dynamics simulations and graph theoretical analysis to understand how temperature regulates n-butanol aggregation and the network properties of water at various concentrations.The theoretical studies suggest that the n-butanol molecules form two distinct alcohol aggregates, water-compatible or water-incompatible, determined by the interactions between alcohol and solvent molecules. Moreover, the proposed bifurcating aggregation pathway is sensitive to the temperature and composition of the n-butanol aqueous solution. The current study shows how temperature is significant in modulating the alcohol aggregation behavior and affects water structure which determines the phase behavior of aqueous solution systems. The effect of temperature on the alcohol aggregation pattern and water structure in n-butanol/water mixtures provides a critical clue in the fundamental understanding and determining the phase behavior of binary water mixtures. The current study also provides a molecular framework to examine and govern the UCST behavior of aqueous solution systems.

Molecular dynamics study on the mechanism of nanofluid coolant's thermal conductivity improvement

With an increase of the heat load of internal combustion engines, the amount of heat that needs to be taken away from the cooling oil chamber is increasing. However, the thermal conductivity of existing coolants is insufficient to discharge this heat out of the internal combustion engine. Nanofluids have higher thermal conductivities than conventional fluids, so they can be considered a solution to the above problem. In this paper, different volume fractions of Cu nanoparticles are added into different coolant solutions, ethanol, ethylene glycol (EG), and propylene glycol (PG), to form alcohol nanofluids. The effect of concentration on the thermal conductivity of ethanol / EG / PG solution was analyzed by molecular dynamics method, and the thermal conductivities of the systems after adding Cu are also calculated and analyzed. It is found that the temperature gradients of the ethanol/EG/PG–water systems decrease gradually with an increase of water content, resulting in an increase of thermal conductivity. The increase of thermal conductivity is mainly due to an adsorption layer of solution atoms on the surfaces of the Cu nanoparticles. 1.5% and 3% volume fractions of Cu nanoparticles can improve the thermal conductivities of the three alcohol solutions by 12.8%, 27.3%, and 16.1%, respectively. Through an analysis of the adsorption layer on the surfaces of the Cu nanoparticles, it is found that the adsorption layer is stratified; that is, water molecules are located in the outer layer, alcohol molecules are in the inner layer, and the stratification of the adsorption layer is different in the different alcohol solutions. In the three alcohols, the delamination sites of the Cu nanoparticles are 2 nm for the ethanol system, 1.8 nm for the PG system, and 1.5 nm for the EG system. The closer the stratification position is to the nanoparticles, the better the mixture of water and alcohol molecules in the adsorption layer, and the higher the thermal conductivity. These results can provide an important reference for the application of nanofluids in internal combustion engines.

Effects of Metallic Impurities in Alkaline Electrolytes on Electro-Oxidation of Water and Alcohol Molecules

The presence of metallic impurities in the electrolyte greatly affects electrocatalytic performance. A systematic study on this topic can not only provide guidance for rigorous practices on electrochemical measurements, but also in-depth fundamental understanding on the mechanisms of the electrochemical reactions. Herein, nine types of metallic ions including Cu2+, Ni2+, Fe3+, Fe2+, Co2+, Mn2+, Zn2+, Ce3+ and Al3+ are intentionally introduced into the electrolytes with a controlled manner and their effects on electro-oxidation of water, 5-hydroxymethylfurfural (HMF) and glycerol are investigated in details. Among these metal ions, Co2+ has the most pronounced effects on H2O electro-oxidation while Cu2+ species displays superior activity toward HMF and glycerol electro-oxidation, but negligible effects on H2O electro-oxidation. Such a unique feature of Cu2+ can also be noted from electro-oxidation of other small molecules, such as ethylene glycol, ethanol and furfural. More importantly, the effects of metallic impurities are independent of the composition of the electrodes, only rely on the pH of the electrolytes. In-situ electrochemical Raman spectroscopy, control electrochemical experiments and X-ray photoelectron spectroscopy analyses reveal that the origin of impurity effects is attributed to the formation of hydroxides during the electrochemical measurements.

Agglomeration of Coniferyl Alcohol Molecules in Aqueous Solutions under Normal and Supercritical Conditions

Agglomeration of Coniferyl Alcohol Molecules in Aqueous Solutions under Normal and Supercritical Conditions