Linear Alcohols Research Articles

Efficient Oxidative Esterification of Furfural Using Au Nanoparticles Supported on Group 2 Alkaline Earth Metal Oxides

Furfural (FF) is a strategic product for the development of highly valued chemicals from biomass. The oxidation product of FF, furoic acid (FA), is an important precursor for the synthesis of green esters, such as methyl furoate. Taking into account issues with the direct furfural oxidation, furfural derivatives, such as alkyl furoates, can be easily prepared via oxidative esterification. Here, Au nanoparticles that were immobilized on alkaline-earth metal oxide supports were studied for the oxidative esterification of furfural while using alcohol as both reactant and solvent. The formation of esters is favored by the presence of basic sites on catalyst surface, resulting in high selectivity, preventing the formation of the acetal as a by-product. The Au/MgO sample provided up to 95% methyl furoate (MF) yield, a fast reaction rate, and high performance for furfural:Au molar ratios between 50 and 300. Furthermore, this catalyst was stable during reuse, since both the selectivity and the activity were maintained after four cycles. Oxidative esterification products were achieved in the presence of other alcohols, leading to the formation of esters of up to C5 (isopentyl furoate) with high selectivity (>99%). Linear and branched esters were formed, but the long-chain linear alcohols resulted in higher yields, such as n-butyl furoate in 94% yield.

Chiral order inorganic mesoporous silica used as stationary phase in gas chromatography

Chiral mesoporous materials have widely applications in chiral separation, asymmetric catalysis, and chiral sensing. Chiral order inorganic mesoporous silica (COIMS) is a kind of chiral materials with high order mesoporous structure not containing organic component. Here we report that a COIMS diluted with a polysiloxane OV-1701 was explored as a novel stationary phase for capillary gas chromatography. The COIMS was synthesized from D-phenylalanine chiral source, and its separation properties of the chiral column were investigated. Eight enantiomers including chiral alcohols, dialcohols, esters and amino acid derivative have been resolved on the coated capillary column. In addition, COIMS chiral column also exhibits good selectivity for the separations of linear alkanes and alcohols. This work indicates that the column has the advantages of high temperature resistance and short analysis time, so it has great potential to develop it as a chiral stationary phase at high temperature.

Hydrogen Bonding in the Liquid State of Linear Alcohols: Molecular Dynamics and Thermodynamics.

Linear monohydroxy alcohols are strongly hydrogen-bonded liquids that are considered to be homologues of water. Here, we report ab initio molecular dynamics simulations of the liquid alcohols, methanol to pentanol, and from the combined radial-angular probability distribution of the intermolecular O···O distances and HO···O angles determine the geometrical parameters that define the hydrogen bonds in these systems. The key feature of hydrogen bonds in the liquid alcohols, irrespective of the size of the alkyl group, is the strong orientation dependence with the donor-acceptor HO···O angle being close to zero, similar to that observed in liquid water. Hydrogen bond formation is consequently considered to be the passage from a state where donor-acceptor pairs show no preferred orientation to one where they are almost linear. The potential of mean force, the reversible work associated with this process, is computed from the pair probability density distributions obtained from the simulations and that for a hypothetical state where donor-acceptor pairs are randomly oriented. We find that the magnitude of the free energy for hydrogen bond formation is maximum for ethanol and show that this arises from a larger electrostatic contribution to hydrogen bond formation in ethanol as compared to the other alcohols.

Race- and sex-specific association between alcohol consumption and hypertension in 22 cohort studies: A systematic review and meta-analysis

Background and aimsThe alcohol–hypertension relation has been well documented, but whether women have protective effect or race and type of beverage consumed affect the association remain unclear. To quantify the relation between total or beverage-specific alcohol consumption and incident hypertension by considering the effect of sex and race. Methods and resultsArticles were identified in PubMed and Embase databases with no restriction on publication date. Pooled relative risks (RRs) and 95% confidence intervals (CIs) were calculated by random effects models. Restricted cubic splines were used to model the dose–response association. This study involved 22 articles (31 studies) and included 414,477 participants. The hypertension risk was different among liquor, wine, and beer at 5.1–10 g/d of ethanol consumption (P-across subgroups = 0.002). The hypertension risk differed between men (RR: 1.14, 95% CI: 1.07, 1.20) and women (RR: 0.98, 95% CI: 0.89, 1.06) at 10 g/d (P-across subgroups = 0.005). We found a linear alcohol–hypertension association among white (P-linearity = 0.017), black people (P-linearity = 0.035), and Asians (P-linearity<0.001). With 10 g/d increment of consumption, the RRs for hypertension were 1.06 (95% CI: 1.04, 1.08), 1.14 (95% CI: 1.01, 1.28), and 1.06 (95% CI: 1.01, 1.10) for Asians, black, and white people, respectively. ConclusionSex modifies the alcohol–hypertension association at low level of alcohol consumption and we did not find evidence of a protective effect of alcohol consumption among women. Black people may have higher hypertension risk than Asians and white people at the same ethanol consumption.

Interaction of Water at the Hydrophobic Interface of Alkyl Group of Alcohol with p‐Nitro‐Aniline Charge Transfer State

AbstractThe evolution of photo‐induced intra molecular charge transfer (ICT) transition energy of p‐nitro‐aniline (PNA), with respect to the mole fraction of alcohol in alcohol water mixture has been used to study, the interaction of hydrophobic hydration ‐shell of linear alcohols with PNA‐ICT state. The linear alcohol ranges from methanol to propanol. The plot of absorption energy of PNA charge transfer transition versus mole fraction of alcohol shows the following features. At lower mole fraction of alcohol, the absorption energy of PNA versus mole‐fraction of alcohol plot at first, decreases below the absorption energy of PNA recorded in pure water and alcohol, goes through a minimum and then increases. Similar behaviour is obtained even after subtracting the contribution from dielectric non‐ideality. The behaviour at lower mole fraction thus indicates the modification of specific interaction of PNA with water due to the presence of alcohol. Further, the absorption energy minimum shifts towards lower mole fraction of alcohol as the chain length of alcohol increases. These results, thus reveals the interaction of PNA with the modified water structure at the hydrophobic interface of alkyl group and supports the current understanding of hydrophobic hydration. To our knowledge, this study for the first time reveals that, hydration shell around hydrophobic group has higher ability to stabilize the PNA‐ICT state by hydrogen bonding interaction compared to bulk water.

Long-chain linear alcohols: Reconciliation of phase transition enthalpies

Thermodynamics of phase transitions of long-chain linear alcohols were revised by means of complementary experimental techniques: transpiration, differential scanning calorimetry (DSC), fast scanning calorimetry (FSC), and solution calorimetry (SC). Absolute vapor pressure temperature dependencies for heptadecanol-1 and octadecanol-1 were measured by the transpiration and FSC methods. The validity and accuracy of the FSC experimental setup towards reliable vapor pressure measurement was established. It was shown that vaporization enthalpies for heptadecanol-1 and octadecanol-1 obtained by FSC and transpiration method are in good agreement. The SC approach was used for estimation of sublimation/vaporization enthalpies of linear alcohols. Energetics of the phase transitions found with the SC-approach agree well with that from conventional methods and they are consistent with each other.

Importance of the electrolyte cation on the non-covalent interactions in the electrooxidation of 1-heptanol on gold in 0.1 M alkali metal hydroxides

In order to determine the possible non-covalent influence of the alkali metal cation on the electrooxidation of 1-heptanol on gold in alkali metal hydroxides, 0.1 M MOH solutions, where M = Li, Na, K, Rb, and Cs, have been used. The charge-transfer resistance, determined by Electrochemical Impedance Spectroscopy, of heptanol oxidation at a fixed potential increased monotonically by a factor of 4 from LiOH to RbOH, that is, the heptanol oxidation current decreased. Since the degree of hydration of the OH group of the alcohol, as estimated by Molecular Dynamics Simulation, increased by a factor of 5 from LiOH to RbOH, it can be concluded that the decrease of the heptanol oxidation current from LiOH to RbOH is due to an increasing hydration of the heptanol OH group, which would hinder its access to the electrode surface. This result is in line with the previous finding [M.S. Ureta-Zañartu, C. Mascayano, C. Gutiérrez, doi:10.1016/j.electacta.2015.02.230] that the increase of the alcohol oxidation current at a fixed potential of linear saturated aliphatic alcohols from C1 to C7 on gold, both in a pH 11 buffer and in 0.1 M NaOH, increased with increasing chain length, that is, with decreasing hydration (because of the increasing hydrophobicity) of the alcoholic OH group.

Effect of biodiesel ester structure optimization on low temperature performance and oxidation stability

The main shortcomings of biodiesel are related to the low-temperature performance and oxidation stability. Hence, this study proposes to investigate the influence of the oleic acid-based esters with various linear and branched chain alcohols on these two properties of biodiesel. The economic impact of biodiesel with various compositions is also evaluated by means of a mathematical model. The results showed that the longer the carbon chain length of the alcohol component, the better the low-temperature performance of the biodiesel. Hence, the cold filter plugging point and solidifying point of methyl oleate were −19 and −24°C, respectively, whereas the cold filter plugging point and solidifying point of amyl oleate were −36 and −41°C, respectively. The more irregular the molecular structure, the better the low-temperature performance of oleic acid-based lipids. For instance, the condensate point and solidifying point of oleic acid-based esters with branched chain alcohols should be lower than oleic acid-based esters with linear chain alcohols. On the other hand, for the linear esters of oleic acid, the oxidation stability is better as the carbon chain is longer. For instance, the induction period of methyl oleate is 0.07h while for amyl oleate, it is 0.36h, which corresponds to an increase of about 5 times. For the branched esters, although they are sensitive to oxidation, the induction period is higher than that of methyl oleate. Finally, the DEA evaluation model was used to analyze the economic aspects of the resulted biodiesel. The results showed that the addition of ethyl oleate to biodiesel significantly improved the low-temperature performance and oxidation stability of biodiesel with good economic benefits.

Normative Pancreatic Stiffness Levels and Related Influences Established by Magnetic Resonance Elastography in Volunteers

Large-scale normative studies of pancreatic stiffness and potential influences have yet to be pursued via magnetic resonance elastography (MRE). To determine normative MRE-based pancreatic stiffness values and to examine related influential factors. Prospective. In all, 361 volunteers (men, 199; women, 162) with a median age of 54.0 years and a median body mass index (BMI) of 22.86 kg/m2 were prospectively recruited. Those with no histories of smoking, alcohol abuse, and diabetes mellitus (DM) were grouped as healthy volunteers, designating all others as positive controls. Each volunteer underwent 3.0T pancreatic MRI at a frequency of 40 Hz. Pancreatic stiffness values, pancreatic width and volume, waist circumference, and wave distance were measured in all subjects. Multiple linear regression analyses were performed to determine variables that influence MRE-determined stiffness. The mean pancreatic stiffness in all volunteers was 1.20 ± 0.16 kPa. Stiffness levels in positive control volunteers proved significantly greater than levels in healthy volunteers (1.29 ± 0.17 kPa vs. 1.14 ± 0.13 kPa; P < 0.001). In multiple linear regression analysis, sex (P = 0.004), BMI (P < 0.001), pancreatic width (P = 0.005), smoking (P < 0.001), alcohol abuse (P < 0.001), and DM (P = 0.001) emerged as significant independent factors impacting pancreatic stiffness. Smoking, alcohol abuse, DM, and wide pancreas were associated with greater pancreatic stiffness (coefficients = 0.202, 0.183, 0.149, and 0.160, respectively), while reduced pancreatic stiffness corresponded with female sex and larger BMI (coefficient = -0.155 and -0.192, respectively). MRE-based pancreatic stiffness values are impacted by sex, BMI, pancreatic width, smoking, alcohol abuse, and DM. Reference values are essential for future clinical studies. 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;52:448-458.

Preparation and properties of novel corn straw cellulose–based superabsorbent with water‐retaining and slow‐release functions

ABSTRACTIn this study, novel semiinterpenetrating polymer networks (semi‐IPNs) superabsorbent resins with slow‐release fertilizer (CSC‐g‐AA/APP, CSC‐g‐AA/PVA‐APP), based on corn straw cellulose polymer and linear polyvinyl alcohol (PVA), were prepared by solution polymerization. The nitric acid‐aqueous solution method was adopted to extract cellulose from corn straw. Ammonium polyphosphate (APP) was introduced to supply nitrogen and phosphorus nutrients. The prepared materials were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X‐ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). Moreover, the water absorbency and the slow‐release performance of CSC‐g‐AA/APP and CSC‐g‐AA/PVA‐APP were studied. The results indicated that the two superabsorbent resins exhibited excellent water absorbency of 262.8 and 303.2 g/g in distilled water, enhanced the water‐holding capacity of soil, and also released nutrients slowly. The cumulative N and P release rates of CSC‐g‐AA/PVA‐APP were 64.47 and 53.53% after 25 days in soil, which were lower than those of CSC‐g‐AA/APP. The addition of these products into soil significantly reduced the leaching losses of nutrients. Therefore, it can be concluded that the superabsorbent resins with water‐retaining and slow‐release properties, low production costs, and environment‐friendly characteristics, have great potential for applications in agricultural production. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48951.

Covalently attachment of aliphatic linear non-branched alcohols to silicon oxide and glass substrates in liquid paraffin solvent

Using liquid paraffin (LP) as a non-polar solvent, aliphatic linear non-branched alcohols (LNA)s, which consist of relatively non-polar alkyl moieties, were covalently attached to the surfaces of oxidized silicon and soda-lime glass (SLG). Atomic force microscope (AFM), home-made grazing angle mirror-backed reflection Fourier transform infrared spectroscopy (GMBR-FTIR) and static water contact angle measurements (WCA) were used to examine the presence as well as the quality of the LNAs monolayers attached to the surface of SLG and oxidized Si(100) surfaces “SiOxSi-(100)”. By using our home-made GMBR-FTIR sampling method the IR signal (in C-H absorption regions) of self-assembled monolayers at both surfaces, SLG wafer and SiOx-Si(100) were directly analyzed. Analysing the AFM image of not fully covered 1-dodecanol (1DD) modified Si(100) surface “1DD-Si(100)”, in which the surface is modified at very low temperature, revealed the thickness of these ultra-thin films (≈1.2 nm) and it seems to be matched with thickness of 1DD-Si(100) monolayers.

Linear β-amino alcohol catalyst anchored on functionalized magnetite nanoparticles for enantioselective addition of dialkylzinc to aromatic aldehydes.

A linear β-amino alcohol ligand, previously found to be a very efficient catalyst for enantioselective addition of dialkylzinc to aromatic aldehydes, has been anchored on differently functionalized superparamagnetic core–shell magnetite–silica nanoparticles (1a and 1b). Its catalytic activity in the addition of dialkylzinc to aldehydes has been evaluated, leading to promising results, especially in the case of 1b for which the recovery by simple magnetic decantation and reuse was successfully verified.

Коагуляционные свойства магнитной жидкости, стабилизированной полидиметилсилоксаном

The stability of a stabilized with polydimethylsiloxane (PDMS) magnetic fluid to alcohols of a saturated homologous series was investigated. We used alcohols with a linear molecular structure and their possible isomers. It was found that the solubility of the PDMS stabilized particles strongly depends on the length of the coagulant molecules and, quite unexpectedly, on the degree of isomerization. The first tested coagulants, ethanol and acetone, did not mix with PDMS stabilized magnetic fluid. The next member of the homologous series, linear propanol, is an effective coagulant that causes a sharp precipitation of particles. Meanwhile, with isopropanol, coagulation occurs very smoothly. The butanol isomers differ even more. Normal butanol causes the liquid to coagulate at a higher concentration than propanol. Whereas tert-butanol is mixed with PDMS stabilized magnetic fluid in any proportion. The last linear alcohol in the homologous series that can serve as a coagulant is hexanol-1. The next members of the homologous series no longer mix with the PDMS stabilized magnetic fluid. This is typical only for linear molecules. For example, 2ethylhexanol (isooctanol) perfectly dissolves PDMS stabilized particles. This property can be used to separate mixtures of isomers and linear molecules.

Geometry of OHO interactions in the liquid state of linear alcohols from ab initio molecular dynamics simulations.

Monohydroxy alcohols are strongly associating liquids with the hydrogen bonding associated with the presence of the hydroxyl group having a significant influence on properties. Here we determine the geometry of the hydrogen bond in linear alcohols, methanol to pentanol, arising from intermolecular OHO interactions, from ab initio molecular dynamics trajectories by plotting the intermolecular non-bonded OHO and OO distances, and the ∠HOO (θ) angles for every possible pair of alcohol molecules in the ensemble. Two regions separate out in the scatter-plot; the one with short OHO and OO intermolecular distances and almost linear ∠HOO angles may be identified as the region where the intermolecular OHO geometry would be favorable for hydrogen bonding. We find that the geometry of the hydrogen bond arising from intermolecular OHO interactions in liquid alcohols shows little change with an increase in size of the alkyl group. This observation is in direct contrast to that in the crystalline state where marked departures in the HOO angle from linearity are seen with an increase in the alkyl chain on going from methanol to pentanol.

Catalyzed chain growth polymerisation of ethylene using lanthanidocenes/dialkylmagnesium: further developments and one pot synthesis of narrow dispersed high molecular weight fatty alcohols

Ethylene polymerisation was performed via an improved in situ Ln/Mg CCG process and applied to the synthesis of high Mn linear alcohols.

Synthesis and Characterization of Potential Bio‐Based Lubricant Basestocks via Epoxidation Process

AbstractChemical modifications of vegetable oils may be applied for the purpose of improving their physicochemical properties in their usage for the bio‐based lubricants. The vegetable oils with a high percentage of oleic acid, such as soybeans and rapeseed oils, are important raw materials to obtain the biolubricants. In this particular study, the oleic acid was esterified with 1‐octanol, followed by epoxidation. The oxirane ring opening reaction was performed using different alcohol structures (linear, branched, and cyclic), in order to evaluate their influence on the final physicochemical properties with the synthesized samples. These aforesaid reaction steps were followed by 1H nuclear magnetic resonance and the main physicochemical properties in the intermediate and final samples were assessed. The highest oxidative stability was observed for the samples obtained, using a cyclic alcohol at the oxirane ring opening reaction (230 min), followed by the linear alcohols with the branched alcohol presenting the lowest oxidative stability (124 min). The pour point values for the samples synthesized with the branched alcohol were slightly better than those with the linear and cyclic alcohols. All the synthesized samples showed high viscosity indexes (&gt;130) and kinematic viscosities at 40 °C, ranging from 30 to 33 cSt (application degree ISO VG‐32), which are adequate for their use in the formulation of bio‐based lubricants.

Physicochemical Properties of the Binary Mixtures of CuII-Containing Chelate-Based Ionic Liquids with Linear Alcohols

Systematic measurements (densities, viscosities, conductivities) combined with small-angle X-ray scattering (SAXS) experiments were performed for binary mixtures of CuII-containing chelate-based io...

Efficient Mild Organosolv Lignin Extraction in a Flow-Through Setup Yielding Lignin with High β-O-4 Content.

Current lignin fractionation methods use harsh conditions that alter the native lignin structure, resulting in a recalcitrant material which is undesired for downstream processing. Milder fractionation processes allow for the isolation of lignins that are high in β-aryl ether (β-O-4) content, however, at reduced extraction efficiency. The development of improved lignin extraction methods using mild conditions is therefore desired. For this reason, a flow-through setup for mild ethanosolv extraction (120 °C) was developed. The influence of acid concentration, ethanol/water ratio, and the use of other linear alcohol co-solvents on the delignification efficiency and the β-O-4 content were evaluated. With walnut shells as model feedstock, extraction efficiencies of over 55% were achieved, yielding lignin with a good structural quality in terms of β-O-4 linking motifs (typically over 60 per 100 aromatic units). For example, lignin containing 66 β-O-4 linking motifs was obtained with an 80:20 n-propanol/water ratio, 0.18 M H2SO4 with overall a good extraction efficiency of 57% after 5 h. The majority of the lignin was extracted in the first 2 hours and this lignin showed the best structural quality. Compared to batch extractions, both higher lignin extraction efficiency and higher β-O-4 content were obtained using the flow setup.

Ligand-Controlled Regiodivergent Silylation of Allylic Alcohols by Ni/Cu Catalysis for the Synthesis of Functionalized Allylsilanes.

The first Ni/Cu-catalyzed regiodivergent synthesis of allylsilanes directly from allylic alcohols through modulating the steric and electronic properties of the ligands on the nickel catalyst has been developed. Good yields and excellent selectivity were obtained regardless of whether linear or α-branched allylic alcohols were utilized. Mechanistic studies indicate that an allyloxyboronate species is formed during the reaction, which likely serves as an activated intermediate toward the oxidative addition of the C(allyl)-O bond.

On the role of cobalt carbidization in higher alcohol synthesis over hydrotalcite-based Co-Cu catalysts

Co-Cu-based catalysts are widely applied in higher alcohol synthesis (HAS) from synthesis gas. Although the nature of the active sites is still not fully understood, the formation of Co 2 C under HAS conditions seems to play a major role. A CO pretreatment procedure was developed allowing a systematic investigation of the influence of cobalt carbidization on the structural properties and catalytic performance of the catalysts. By exposing the catalyst to a CO-containing atmosphere prior to HAS, Co enrichment of the catalyst surface occurred followed by carbide formation. This surface modification decreased the formation of hydrocarbons and enhanced the formation of C 2+ OH. The catalyst pretreated with CO at 20 bar achieved the highest selectivity to ethanol and the lowest hydrocarbon selectivity. CO pretreatment at elevated pressure enhances the selectivities to linear alcohols through surface cobalt enrichment and carbide formation.