Alcoholic Hydroxyl Research Articles

Pequi Oil Esters as an Alternative to Environmentally Friendly Lubricant for Industrial Purposes

This study reports the synthesis of bio-based lubricants using pequi oil (PO) as a raw material, along with its chemical, thermal, and rheological characterization, as well as its cytotoxic behavior and the kinetic study of the reaction involved in the production of biolubricants. Free fatty acid pequi oil (PFFA) was esterified using 2-ethyl-1-hexanol (P2EHE), pentaerythritol (PPEE), and p-TSA as catalysts. The 1H NMR spectra confirmed the replacement of hydroxyl groups of both alcohols by PFFA. PPEE showed better thermal stability (Tonset 274.50 °C). Besides, at 50% of thermal weight loss, the PPEE showed a higher decomposition temperature (437.9 °C) than PO (366.6 °C). The melting points determined by DSC indicate that P2EHE exhibits better performance at low temperatures (p.p. −22.86 °C) than PPEE (p.p. −33.28 and 8.02 °C) due to the presence of some crystals of saturated fatty acids in the pentaerythritol ester. The esters showed Newtonian behavior in a wide range of shears; however, they showed pseudoplastic behavior at temperatures above 60 °C. The viscous nature of bio-based lubricants was confirmed (G″ > G′) even with increasing temperature. The kinetic study provided the value of the activation energy to P2EHE and PPEE, similar to that reported in the literature for other types of biolubricants. The toxicity analysis of bio-based lubricants on adult zebrafish showed no lethality after 96 h. These results suggest that pequi oil is a potential raw material to produce lubricants that are less harmful to the environment.

Preparation of rigid polyurethane foam from lignopolyol obtained through mild oxypropylation.

Lignin, one of the main components of lignocellulose, can be used as an alternative to chemical polyols in the production of polyurethane because of its abundant phenolic and alcohol hydroxyls. Traditionally, lignin is directly applied in the preparation of polyurethane; however, modified lignin has been proved to be superior, especially that obtained by the oxypropylation reaction. Therefore, lignopolyol obtained by mild and efficient oxypropylation was utilized in the production of rigid polyurethane foam in this study. Specifically, the effects of the content of lignopolyol on the chemical structure, morphological structure, mechanical properties and thermal stability of the lignin-based rigid polyurethane foam were investigated. It was found that the compressive strength of the rigid polyurethane foam was significantly improved with the addition of lignopolyol compared with that of the pure polyurethane foam, which was attributed to the fact that oxypropylation made lignin into highly branched and functionalized polyols by transforming all phenolic hydroxyls into aliphatic hydroxyls. Moreover, when the molal weight of lignopolyol accounted for 40% of the added polyols, the generated foam showed optimal uniformity and regularity, and the compressive strength reached 0.18 MPa, meeting the requirements of industrial application, below which, the amount of undesired reactions is bound to increase. As a consequence, the added amount of lignopolyol was increased as much as possible on the basis of guaranteeing the desired properties, which was more conducive to realizing the green degradation and economic synthesis of rigid polyurethane foam.

Alcohol hydroxides regulate the growth of Ni-Co layered double hydroxides on carbon fiber cloth as supercapacitor electrode materials

There is a need to design and fabricate Ni-Co layered double hydroxides (Ni-Co LDHs) with high specific capacity, rate capability, and energy density for use as supercapacitor electrode materials. In this study, Ni-Co LDHs are directly grown on the flexible carbon fiber cloth (CFC) substrate by low-carbon alcohol/water solvothermal method. It is found that the morphology of Ni-Co LDHs changes from a wire-like structure to a lamellar structure because of the increased number of alcoholic hydroxyl groups, and the wire-like structure is more favorable for charge transfer and ion diffusion. The number of alcoholic hydroxyl groups has a greater impact on the morphological and electrochemical properties of Ni-Co LDHs compared with the n-propanol content. The Ni-Co LDH@CFC with well cycling stability can be obtained at a n-propanol/water volume ratio of 6:4 and a Ni/Co molar ratio of 1:1. The specific capacity reaches 1102 C g−1 at 2 A g−1 and 70% of the initial capacitance can be retained at 30 A g−1. A button-type asymmetric supercapacitor (ASC) Ni-Co LDH@CFC//AC with an energy density of 39 Wh kg−1 and a power density of 1450 W kg−1 has been successfully fabricated. This work may provide insights into the preparation of high-performance electrode materials with tunable architectures by regulating the number of alcoholic hydroxyl groups.

Quantum Chemistry Calculation Study on Chain Reaction Mechanisms and Thermodynamic Characteristics of Coal Spontaneous Combustion at Low Temperatures.

The coal spontaneous combustion phenomenon seriously affects the safety production of coal mines. Aiming at the problem of complex coal molecular structure and incomplete reaction sequences at present, the mechanisms and thermodynamic parameters of coal spontaneous combustion chain reactions were explored by combining experimental detections and molecular simulations. First, the active groups on the surface of coal were obtained by Fourier transform infrared spectroscopy (FTIR), mainly including methyl (−CH3), methylene (−CH2), methyne (−CH), phenolic hydroxyl (−ArOH), alcohol hydroxyl (−ROH), carboxyl (−COOH), aldehyde (−CHO), and ether (−O−), and the coal molecular models containing functional groups and radicals were established. According to the charge density, electrostatic potential, and frontier orbital theories, the active sites and active bonds were obtained, and a series of reactions were given. The thermodynamic and structural parameters of each reaction were explored. In the chain initiation reaction stage, O2 chemisorption and the self-reaction of radicals play a leading role. In this stage, heat gradually accumulates and various radicals begin to generate, where the intramolecular hydrogen transfer reaction of a peroxide radical (−C–O–O·) can produce the key hydroxyl radical (−O·). In the chain propagation reaction stage, O2 and −O· continuously consume active sites to accelerate the reaction sequences and increase the temperature of coal, and index gases such as CO and CO2 generate, causing the chain cycle reactions to gradually form. The chain termination reaction stage is the formation of stable compounds such as ethers, esters, and quinones, which can inhibit the development of chain reactions. The results can further explain the reaction mechanism of coal spontaneous combustion and provide references for the development and utilization of chemical inhibitors.

3-O-Carbamoyl-5,7,20-O-trimethylsilybins: Synthesis and Preliminary Antiproliferative Evaluation.

To search for novel androgen receptor (AR) modulators for the potential treatment of castration-resistant prostate cancer (CRPC), naturally occurring silibinin was sought after as a lead compound because it possesses a moderate potency towards AR-positive prostate cancer cells and its chemical scaffold is dissimilar to all currently marketed AR antagonists. On the basis of the structure–activity relationships that we have explored, this study aims to incorporate carbamoyl groups to the alcoholic hydroxyl groups of silibinin to improve its capability in selectively suppressing AR-positive prostate cancer cell proliferation together with water solubility. To this end, a feasible approach was developed to regioselectively introduce a carbamoyl group to the secondary alcoholic hydroxyl group at C-3 without causing the undesired oxidation at C2–C3, providing an avenue for achieving 3-O-carbamoyl-5,7,20-O-trimethylsilybins. The application of the synthetic method can be extended to the synthesis of 3-O-carbamoyl-3′,4′,5,7-O-tetramethyltaxifolins. The antiproliferative potency of 5,7,20-O-trimethylsilybin and its nine 3-carbamoyl derivatives were assessed in an AR-positive LNCaP prostate cancer cell line and two AR-null prostate cancer cell lines (PC-3 and DU145). Our preliminary bioassay data imply that 5,7,20-O-trimethylsilybin and four 3-O-carbamoyl-5,7,20-O-trimethylsilybins emerge as very promising lead compounds due to the fact that they can selectively suppress AR-positive LNCaP cell proliferation. The IC50 values of these five 5,7,20-O-trimethylsilybins against the LNCaP cells fall into the range of 0.11–0.83 µM, which exhibit up to 660 times greater in vitro antiproliferative potency than silibinin. Our findings suggest that carbamoylated 5,7,20-O-trimethylsilybins could serve as a natural product-based scaffold for new antiandrogens for lethal castration-resistant prostate cancer.

Synthesis of Planar Chiral 2-Aryl Aroylferrocenes via Palladium-Catalyzed C-C Bond-Cleavage/Ring-Opening Reaction.

A palladium-catalyzed ring-opening reaction of optically active ferrocenyl tertiary alcohols for the construction of planar chiral ketones is reported. The stereochemistry of the hydroxyl group in ferrocenyl alcohols markedly affects reaction: ferrocenyl alcohols with a β-hydroxyl group show better reactivity and chemoselectivity than the corresponding α-hydroxyl analogues. The treatment of α-hydroxyl substrates with trifluoroacetic acid successfully realizes the inversion of the orientation of hydroxyl group to the corresponding β-analogues.

Characterization of heavy metals and oil components in the products of oily sludge after hydrothermal treatment

In this study, the method combining hydrothermal treatment (HT) and in-situ mechanical compression (MC) is used to treat oily sludge. The possible transfer and reaction pathways of different oil components during the process of HT&MC were investigated. In addition, the leaching toxicity, distribution, and risk of heavy metals in oily sludge treated in different temperatures and residence times were evaluated. The results revealed that siloxane and heavy oil components are left in the solid residue, and the light oils and oils with hydrophilic groups are transferred to hydrothermal fluids. The content of Cd, Cr, Pb, and Zn in form of F4 (residual) in the solid residue obtained at a hydrothermal temperature of 240 °C and residence time of 60 min increased by 7.37%, 1.21%, 3.06%, and 9.97%. This reduced the biological availability and environmental risk of heavy metals in the treated oily sludge. Meanwhile, the result of FT-IR illustrated an increase in hydroxyl groups of alcohols, phenols and organic acids, which have a beneficial effect on the adsorption of heavy metals and other pollutants. All results indicated that HT&MC might be a suitable pretreatment method for the stabilization of heavy metals in oily sludge.

Quantum Chemical Calculation of the Effects of H2O on Oxygen Functional Groups during Coal Spontaneous Combustion.

The effects of H2O on the low-temperature oxidation characteristics of coal have always been one of the keys in the research of coal spontaneous combustion, but most studies rely on experiments for macroscopic derivation, and theoretical researches at the microlevel are rarely mentioned. In this paper, phenylacetaldehyde, phenylethyl alcohol, phenylacetic acid, and ethylbenzene hydroperoxide were used as modeling compounds of coal molecules containing aldehyde (−CHO), alcohol hydroxyl (−OH), carboxyl (−COOH), and peroxide (−C–O–OH). The surface electrostatic potential (ESP), electron density of atoms in molecules (AIM), and reduced density gradient (RDG) of coal molecules were calculated by density functional theory (DFT), and the thermokinetic parameters of low-temperature oxidation of coal molecules with or without H2O were analyzed. The results show that the extreme positive and negative ESPs are located at the H and O atoms of oxygen functional groups (OFGs), respectively, which are the active sites for H2O adsorption. The AIM and RDG show that the phenylacetaldehyde···H2O complexes have two kinds of adsorption configurations with two and three hydrogen bonds, and that the phenylethyl alcohol···H2O complexes also have two kinds of adsorption configurations with one and three hydrogen bonds, and that both phenylacetic acid···H2O and ethylbenzene hydroperoxide···H2O only have one adsorption configuration, forming two and three hydrogen bonds, respectively. According to electron density ρ(r) and potential energy density V(r), the adsorption strength of H2O by four kinds of oxygen functional groups is ranked as −C–O–OH > −COOH > −OH > −CHO. The thermokinetic parameters show that H2O can increase the activation energy (ΔE) of the oxidation reactions of phenylacetaldehyde and phenylethyl alcohol, which can inhibit the reaction and decrease the activation energy (ΔE) of the oxidation reaction of phenylacetic acid and ethylbenzene hydroperoxide, which can promote the reactions.

Surface properties of oxidized lignite and its application in congo red dye adsorption

ABSTRACT Lignite is easily oxidized, and spontaneous combustion occurs during its storage, which greatly reduces its calorific value and affects its quality and economic benefits. The surface properties of the oxidized lignite including pore structure and oxygen-containing functional groups were investigated by N2 adsorption/desorption isotherms and Fourier transform infrared spectroscopy. The adsorption of Congo red dye in aqueous solution by oxidized lignite was carried out. It was observed that due to oxidation, the specific surface area and total pore volume of the Huolinhe lignite samples decreased, and the average pore size increased. As oxidation temperature increased, the number of microporous and mesoporous structures decreased, resulting in the decrease of fractal dimension. The hydroxyl content was negatively correlated with the oxidation temperature, but the carbonyl content showed an opposite trend. At the initial stage of oxidation, the rate of hydroxyl consumption is higher than that of formation. The reaction to generate carbonyl, such as the oxidation of aliphatic hydrocarbons, alcohol hydroxyl groups and ethers, requires a higher reaction temperature, so the carbonyl content increased when the temperature was higher than 70 °C. Oxidized lignite was used to adsorb Congo red dye in aqueous solution, and the removal increased significantly with increasing oxidation temperature. Therefore, oxidized lignite can effectively remove Congo red dye from aqueous solution, so as to improve the economic benefit of oxidized lignite.

Fabrication of Carbon-Alumina Composites via Catalytic Pyrolysis of Pine Sawdust on Aluminum Dross for Cr(VI) Removal.

Carbon–alumina composites are prepared for the efficient removal of Cr(VI) from wastewater. Pristine and acid-treated alumina dross (AD and AAD) are copyrolyzed with pine sawdust to form the respective composites, ADPC and AADPC. Excellent absorption properties with Cr(VI) removal efficiency of 95.08% are demonstrated at 60 °C for an initial concentration of 6 μg/mL. The composites combine the merits of char, which provides a high surface-to-volume ratio with abundant functional groups on the surface, and alumina, which provides metal ions for coprecipitation. Carbon structures of pine, char, and composite were analyzed semiquantitatively using 13C NMR by a curve-fitting method. Cr(VI) adsorption is accurately described with chemisorption by the Langmuir isotherm model and a pseudo-second-order kinetic model. The results show that AADPC has more alcohol hydroxyl groups substituted to glucosyl units in amorphous cellulose assigned to the peak at 80 ppm and hemicellulose assigned to peaks at 97 and 101 ppm. Also, it has more phenolic groups in lignin distributed at syringyl units assigned to peaks at 129 and 146 ppm. These oxygen-containing functional groups have a significant influence on Cr(VI) adsorption and reduction to Cr(III) governed by the mechanisms of diffusion, adsorption, complexation, reduction, and coprecipitation. The results of this work provide a new direction for the reuse of biomass and industrial solid wastes to fabricate higher value-added products, i.e., adsorption materials for Cr(VI) removal and stabilization.

Catalytic transfer hydrogenation of levulinic acid to γ-valerolactone over an acids-base trifunctional Hf-bagasse coordination complex derived catalyst

Both value-added utilization of agricultural waste to prepare catalytic materials and selective conversion of biomass-based carbonyl compounds are hot topics. Herein, sugarcane bagasse (SB), a main by-product of cane sugar manufacturing industry, was directly assembled with HfCl4 and methanesulfonic acid (MSA) via a one-step hydrothermal method for scalable preparation of Hf-containing coordination complex (Hf@SB-MSA). Characterization results revealed that the coordination between Hf4+ and phenolic hydroxyl, alcohol hydroxyl, carboxyl groups in SB resulting in the formation of Lewis acid (LA) and Lewis base (LB) sites, while sulfonic group in MSA providing Brønsted acid (BA) sites. The cooperative role of LA, BA and LB in Hf@SB-MSA delivered prominent catalytic performance for catalytic transfer hydrogenation (CTH) of levulinic acid (LvA) to γ-valerolactone (GVL) with isopropanol as solvent and H-donor at mild reaction conditions (GVL yield was up to 99.1%). Heterogeneity and recycling experiments further revealed the good recyclability of Hf@SB-MSA, which can be easily separated from the reaction mixture by filtration and repetitively used at least five reaction runs without an obvious loss of activity. More gratifyingly, Hf@SB-MSA also displayed superior universality for the CTH of various carbonyl compounds to their corresponding alcohols with yields up to 90%.

Obtaining a copolymer of polyhexamethylene guanidine hydrochloride and polyvinyl alcohol

The possibility of obtaining a polymer gel based on polyhexamethylene guanidine hydrochloride and polyvinyl alcohol under conditions of acid catalysis is considered. It was shown that the use of formaldehyde as a crosslinking agent leads to the formation of methylene bridges between the hydroxyl groups of polyvinyl alcohol and the amino groups of polyhexamethylene guanidine hydrochloride. The study of samples obtained by IR spectroscopy revealed the presence of corresponding signals of functional groups at 2780 cm-1 (isolated methylene group between nitrogen and oxygen atoms) and 1580 cm-1 (characteristic band of the guanidine group).

One-Pot Synthesis of Schiff Bases by Defect-Induced TiO2-x-Catalyzed Tandem Transformation from Alcohols and Nitro Compounds.

Schiff bases that are generally formed from condensation reactions of aldehydes (or ketones) and amino groups could also be produced by a photodriven one-pot tandem reaction between alcohols and nitro compounds, in our case. Herein, TiO2-x porous cages derived from NH2-MIL-125 by a self-sacrificing template route are used to study the organic transformation and exhibit 100% conversion efficiency of nitrobenzene and 100% selectivity for Schiff bases in the system of benzyl alcohol (5 mL) and nitrobenzene (41 μL) upon light irradiation, but hydrogen by dehydrogenation of benzyl alcohol cannot be detected. Successful occurrence of the organic transformation is mainly attributed to Ti(III)-oxygen vacancy associates. Surface oxygen vacancy-related Ti(III) sites are responsible for binding with nitro groups, and low-coordinated Ti5c sites selectively adsorb hydroxyl groups of benzyl alcohol. The Ti(III) and oxygen vacancy associates capture photogenerated electrons for achievement of multielectron reduction of nitrobenzene and the subsequent Schiff base condensation reaction with the as-formed benzaldehyde.

Steam reforming of alcohols and carboxylic acids: Importance of carboxyl and alcoholic hydroxyl groups on coke properties

Alcohols and carboxylic acids have been used intensively as feedstock for production of hydrogen via steam reforming. They have different functionalities and might exhibit the distinct coking behaviors. In this study, ethanol, n-propanol, acetic acid and propionic acid were chosen as the representatives of alcohols/carboxylic acids and their reaction characteristics in steam reforming over Ni/SBA-15 catalyst were comparatively investigated with the focus on understanding the difference of the properties of the coke formed. The results indicated that although the steam reforming of the alcohols generated more coke than that of the carboxylic acids, the catalyst showed the higher catalytic stabilities, due to different properties of the coke formed. The steam reforming of the alcohols produced the coke of higher aromaticity with a higher content of carbon, more large defective aromatic rings, higher crystallinity, higher thermal stability and resistivity towards the oxidation than that from steam reforming of the carboxylic acids. The coke in the carbon nanotube form in steam reforming of the alcohols and the carboxylic acids also differed in terms of wall thickness and length of the carbon nanotubes, as the reaction intermediates were different. The encapsulating coke was more abundant in steam reforming of carboxylic acids, as carboxylic acids are prone to form the amorphous thermal coke via cracking, which led to rapid deactivation of the catalyst. The types or properties of the coke, not only the amount, play important roles in determining stability of the catalyst.

Chain Propagation Mechanism of Fischer–Tropsch Synthesis: Experimental Evidence by Aldehyde, Alcohol and Alkene Addition

Fischer–Tropsch synthesis (FTS) produces hundreds of hydrocarbons and oxygenates by simple reactants (CO + H2) and the detailed chain propagation mechanism is still in dispute. An industrial iron-based catalyst was used to further clarify the mechanism by adding aldehyde, alcohol and alkene species into a fixed-bed tubular reactor. The added species were investigated in H2 and syngas atmospheres, respectively. 1-alkene in the H2 atmosphere presented an obvious hydrogenolysis, in which the produced C1 species participated in C–C bond formation simultaneously. Co-feeding Cn alkene with syngas showed remarkable Cn+1 alcohol selectivity compared to the normal FTS reaction. In addition, the carbonyl group of aldehyde was extremely unstable over the iron-based catalyst and could easily be hydrogenated to an alcohol hydroxyl group, which could even undergo dehydration for hydrocarbon species formation. Experimental data confirmed that both heavier alkenes and alcohols added can be converted to chain growth intermediates and then undergo monomer insertion for chain propagation. These results provide strong evidence that the chain propagation in the FTS reaction is simultaneously controlled by the surface carbide mechanism and the CO insertion mechanism, with surface CHx species and CO as monomers, respectively. The study is of guiding significance for FTS mechanism understanding and kinetic modeling.

High molecular weight of polylactic acid (PLA): A Review on the effect of initiator

This article reviews various initiator used to synthesize high molecular weight (MW >10,000 g/mol) of polylactic acid (PLA) through ring-opening polymerisation (ROP) of lactide. ROP has been chosen as the best method in producing PLA. On the other hand, stannous octoate (Sn(Oct)2) has been reported as the best catalyst used for ROP method. Many researchers have studied that polymerisation rate with the presence of only Sn(Oct)2 as catalyst is slow compared to polymerisation of lactide with the presence of initiator. An initiator is also favourable in producing high molecular weight of PLA as it can initiate the synthesis of PLA. Therefore, this review focus on ROP method catalysed by Sn(Oct)2 using different solvent as initiator. Among groups of initiators being reviewed are hydroxyl, carboxylic acid, aldehyde, aliphatic polyester and organophosphorus compound. Most of the studies applied in nitrogen atmosphere with a temperature range of 125 to 200 °C, while only one study in vacuum condition. Duration of the polymerisation time is between 1 to 24 hours. Based on the review, alcohol (hydroxyl group initiator) has been reported as the best initiator to produce high molecular weight of PLA. This functional group act as co-initiator molecule that reacts with Sn(Oct)2, forming the initiating stannous alkoxide linkage. The linkage is necessary to propagate monomer addition and hence increase the MW.

Experimental and DFT investigation of structure and IR spectra of H-bonded associates of p-(3-carboxy-1-adamantyl)thiacalix[4]arene.

The IR spectra of p-(3-carboxy-1-adamantyl)thiacalix[4]arene (1-AdCOOHTC4A) have been studied. IR spectra of crystalline 1-AdCOOHTC4A obtained at room temperature or upon heating to 250°C or its dilute solutions lack bands of free hydroxyl groups. The frequency of hydroxyl groups at 3377cm-1 indicates the formation of an intramolecular H-bond along the lower rim of the 1-AdCOOHTC4A molecule. On the top edge of thiacalixarene, the carboxyl groups form dimeric or cyclic tetrameric complexes via intermolecular H-bonds. The conformation of the cone persists, but there is a mutual influence of H-bonds along the upper and lower rims of the thiacalix[4]arene molecule. The structure with dimer H-bonds between carboxyl groups is 31.9 KJ/mol less preferable than the conformation with tetramer cyclic H-bonds for 1-AdCOOHTC4A. Comparison of the absorption band of νOH alcohol hydroxyl groups in the IR spectra of 1-AdCOOHTC4A at 3377cm-1, with the corresponding band of 1-AdTC4A at 3372cm-1, suggests that the presence of the second system of H-bonds of carboxyl groups in the first molecule does not affect the H-bond of alcohol hydroxyl groups.

Real-time monitoring the carbonization and activation process of activated carbon prepared from Chinese parasol via zinc chloride activation

The study of carbonization and activation mechanism is essential for the preparation of high-performance biomass-based activated carbon (AC), which has been widely used in many fields. In this work, an online volatile analysis and real-time sampling was carried out to study the carbonization and activation mechanism of AC prepared by pyrolysis of Chinese parasol sawdust and ZnCl2 mixture. Combining a series of analysis results, it was found that the effect of ZnCl2 could be divided into three stages: (1) At low temperature (<300 °C), it promoted the depolymerization and dehydration of hemicellulose to release furfural, but inhibited the release of other small molecules produced from hemicellulose, cellulose and lignin; (2) It catalyzed the dehydration of alcoholic hydroxyl groups and the cleavage of phenol/ether CO bonds in solid residues at 300−400 °C; (3) It catalyzed the aromatization reaction at temperatures ≥ 400 °C, and formed a large number of pore structures through the swelling effect of ZnCl2 and the release of small molecular gases. 2308 m2/g of micropore AC with micropore ratio of 71.9 % and 2057 m2/g mesoporous AC with mesoporous ratio of 58.6 % were obtained when the temperature just rose to 500 °C and 550 °C, respectively. No additional activation time was required, which helped to save time and energy consumption in AC production.

Shear viscosity prediction of alcohols, hydrocarbons, halogenated, carbonyl, nitrogen-containing, and sulfur compounds using the variable force fields.

Viscosity of organic liquids is an important physical property in applications of printing, pharmaceuticals, oil extracting, engineering, and chemical processes. Experimental measurement is a direct but time-consuming process. Accurately predicting the viscosity with a broad range of chemical diversity is still a great challenge. In this work, a protocol named Variable Force Field (VaFF) was implemented to efficiently vary the force field parameters, especially λvdW, for the van der Waals term for the shear viscosity prediction of 75 organic liquid molecules with viscosity ranging from -9 to 0 in their nature logarithm and containing diverse chemical functional groups, such as alcoholic hydroxyl, carbonyl, and halogenated groups. Feature learning was applied for the viscosity prediction, and the selected features indicated that the hydrogen bonding interactions and the number of atoms and rings play important roles in the property of viscosity. The shear viscosity prediction of alcohols is very difficult owing to the existence of relative strong intermolecular hydrogen bonding interaction as reflected by density functional theory binding energies. From radial and spatial distribution functions of methanol, we found that the van der Waals related parameters λvdW are more crucial to the viscosity prediction than the rotation related parameters, λtor. With the variable λvdW-based all-atom optimized potentials for liquid simulations force field, a great improvement was observed in the viscosity prediction for alcohols. The simplicity and uniformity of VaFF make it an efficient tool for the prediction of viscosity and other related properties in the rational design of materials with the specific properties.

Pichia galeiformis Induces Resistance in Postharvest Citrus by Activating the Phenylpropanoid Biosynthesis Pathway.

This study aimed to investigate the effect of Pichia galeiformis on disease resistance and elucidate the changes in phenylpropane biosynthesis treated by P. galeiformis in postharvest citrus. The results showed that P. galeiformis reduced the disease incidence and lesion diameters without direct contact with the pathogen Penicillium digitatum. Transcriptome analysis revealed that phenylpropanoid biosynthesis was triggered by P. galeiformis. Genes encoding phenylpropanoid biosynthesis were upregulated, including phenylalanine ammonia-lyase (PAL), 4-coumaroyl-CoA ligase (4CL), cinnamate-4-hydroxylase (C4H), peroxidase (POD), cinnamyl alcohol dehydrogenase (CAD), O-methyltransferase, and hydroxyl cinnamoyl transferase. Moreover, P. galeiformis increased the activity of PAL, 4CL, C4H, POD, polyphenol oxidase, and CAD in citrus pericarp. In addition, P. galeiformis treated citrus displayed higher levels of total phenolic compounds, flavonoid, and lignin and higher amounts of ferulic and sinapic acid. In conclusion, these results suggested that P. galeiformis could induce resistance through modulating the pathway of phenylpropanoid biosynthesis in postharvest citrus.