Hydrogen-bonding Associations Research Articles

Engineering Tough Supramolecular Hydrogels with Structured Micropillars for Tunable Wetting and Adhesion Properties.

Soft-lithography is widely used to fabricate microstructured surfaces on plastics and elastomers for designable physical properties such as wetting and adhesions. However, it remains a big challenge to construct high-aspect-ratio microstructures on the surface of hydrogels due to the difficulty in demolding from the gel with low strength and stiffness. Demonstrated here is the engineering of tough hydrogels by soft-lithography to form well-defined micropillars. The mechanical properties of poly(acrylamide-co-methacrylic acid) hydrogels with dense hydrogen-bond associations severely depend on temperature, with Young's modulus increasing from 8.1MPa at 15°C to 821.8MPa at -30°C, enabling easy demolding at low temperatures. Arrays of micropillars are maintained on the surface of the gel, and can be used at room temperature when the gel restores soft and stretchable. The hydrogel also exhibits good shape-memory property, favoring tailoring the morphology with a switchable tilt angle of micropillars. Consequently, the hydrogel shows tunable wetting and adhesion properties, as manifested by varying contact angles and adhesion strengths. These surface properties can also be tuned by geometry and arrangement of micropillars. This facile strategy by harnessing tunable viscoelasticity of supramolecular hydrogels should be applicable to other soft materials, and broaden their applications in biomedical and engineering fields.

Relationship between synthesis method-crystal structure-melting properties in cocrystals: the case of caffeine-citric acid.

The influence of the crystal synthesis method on the crystallographic structure of caffeine-citric acid cocrystals was analyzed thanks to the synthesis of a new polymorphic form of the cocrystal. In order to compare the new form to the already known forms, the crystal structure of the new cocrystal (C8H10N4O2·C6H8O7) was solved by powder X-ray diffraction thanks to synchrotron experiments. The structure determination was performed using `GALLOP', a recently developed hybrid approach based on a local optimization with a particle swarm optimizer, particularly powerful when applied to the structure resolution of materials of pharmaceutical interest, compared to classical Monte-Carlo simulated annealing. The final structure was obtained through Rietveld refinement, and first-principles density functional theory (DFT) calculations were used to locate the H atoms. The symmetry is triclinic with the space group P-1 and contains one molecule of caffeine and one molecule of citric acid per asymmetric unit. The crystallographic structure of this cocrystal involves different hydrogen-bond associations compared to the already known structures. The analysis of these hydrogen bonds indicates that the cocrystal obtained here is less stable than the cocrystals already identified in the literature. This analysis is confirmed by the determination of the melting point of this cocrystal, which is lower than that of the previously known cocrystals.

Synthesis of Novel (Meth)acrylates with Variable Hydrogen Bond Interaction and Their Application in a Clear Viscoelastic Film.

Clear viscoelastic films (CVFs) have many applications in the display industry. Acrylic monomers containing a hydrogen bond (H-monomer) are often used in the preparation of CVF to increase the cohesion and form favorable interactions with the display substrate. Common H-monomers face a counterbalance between the glass transition temperature (Tg) and the hydrogen-bonding association constant (Ka). Strong hydrogen bonding often leads to a high Tg and high modulus, which are unfavorable in certain applications such as foldable display. To solve these problems, four types of hydrogen-bonding (meth)acrylic monomers (carbamate acrylate, carbamate methacrylate, urea acrylate, and urea methacrylate) with different Ka and Tg were readily synthesized. Among them, urea acrylates displayed the highest Ka while still maintaining moderate Tg. These H-monomers were copolymerized with 2-ethylhexyl acrylate (EHA) and cross-linked to obtain a series of copolymers (H-copolymers) as pressure-sensitive adhesives. After the characterization of rheology, optics, and peel adhesion, urea-acrylic H-copolymers showed the best overall performance by combining great optical property (>98% in transmittance, < 1% in haze) and mechanical performance (8-12 N/25 mm in peel adhesion, 84-92% in creep recovery). This work provides a new path to prepare acrylic CVF for flexible display application.

Polyurethane hard domain composed of mixed hard segments

AbstractThe packing of hard segment in polyurethane hard domain has not been resolved or seen clearly yet. In this work, we prepared polyurethane blends, which were composed of different weight ratios of crystallizable 1195A and non‐crystallizable EG85A, to study the structural evolution and crystallization in mixed hard domain. Time and temperature dependent differential scanning calorimetry, Fourier transform infrared spectroscopy (FTIR), and x‐ray diffraction results were used to record the micro‐phase evolution and crystallization processes. It was very surprising to find that the multiple melting temperatures in these blends were similar. We deduced that the packing of hard segment tended to separate into different groups, probably dependent on their segmental length. The crystalline nucleus was consist of 1195A hard segments with similar length, and the out‐layer structure was consisted of mixed hard segments of varying lengths. The FTIR results demonstrated that crystallinity did not affect the degree of hydrogen bonding association (HBA), and the stacking of hard segments may be only differed in the degree of ordering. Moreover, the degree of HBA of the blends was always higher than the calculated number based on weight ratio of pure samples.

Self-compliant ionic skin by leveraging hierarchical hydrogen bond association

Robust interfacial compliance is essential for long-term physiological monitoring via skin-mountable ionic materials. Unfortunately, existing epidermal ionic skins are not compliant and durable enough to accommodate the time-varying deformations of convoluted skin surface, due to an imbalance in viscosity and elasticity. Here we introduce a self-compliant ionic skin that consistently works at the critical gel point state with almost equal viscosity and elasticity over a super-wide frequency range. The material is designed by leveraging hierarchical hydrogen bond association, allowing for the continuous release of polymer strands to create topological entanglements as complementary crosslinks. By embodying properties of rapid stress relaxation, softness, ionic conductivity, self-healability, flaw-insensitivity, self-adhesion, and water-resistance, this ionic skin fosters excellent interfacial compliance with cyclically deforming substrates, and facilitates the acquisition of high-fidelity electrophysiological signals with alleviated motion artifacts. The presented strategy is generalizable and could expand the applicability of epidermal ionic skins to more complex service conditions.

Double-Network Organohydrogels Toughened by Solvent Exchange.

Double-network hydrogels based on calcium alginate are extensively exploited. Unfortunately, their low strength and unstable constitution to open environments limit their application potential. Herein, a new type of double-network organohydrogel (OHG) is proposed. By solvent exchange, a stable physical network is established based on dimethyl sulfoxide (DMSO)-alginate in the presence of a polyacrylamide network. The DMSO content endows tunable mechanical properties, with a maximum tensile strength of ≈1.7MPa. Importantly, the OHG shows much better environmental stability compared to the conventional double-network hydrogels. Due to the reversible association of hydrogen bonds, the OHG possesses some unique properties, including free-shapeability, shape-memory, and self-adhesion, that offers several promising ways to utilize alginate-based gels for wide applications.

Structure of tert-butyl alcohol in carbon tetrachloride solution. Molecular dynamics simulation study

The structure of tert-butyl alcohol (TBA) solution in carbon tetrachloride (CCl4) is studied over the entire concentration range using molecular dynamics simulation (MD). It is shown that at low alcohol concentrations (within 5% molar fraction), separate small associates of TBA appear as a result of hydrogen bonding between alcohol molecules, and cyclic structures of four TBA molecules appear among these associates. With increasing concentration, the formation of hydrogen-bonded associates quickly reaches its limit corresponding to 1.7 bonds per molecule as in pure TBA. At high alcohol concentrations, both linear and cyclic associates of TBA molecules are observed with a noticeable fraction of cyclic tetramers. Using the Voronoi method, aggregates of the nearest TBA molecules are considered. The number and size of such aggregates grows rapidly with concentration due to the presence of “nuclei” formed by hydrogen bonding. At an alcohol mole fraction of 15%, a percolation cluster of TBA molecules begins to form in the solution. On the contrary, in the local environment of CCl4 molecules no significant structural rearrangements occur, only a gradual replacement of the molecules is observed upon addition of alcohol. However at low content of CCl4 in alcohol, we can see some tendency to clustering of CCl4 molecules, which may indicate on a slight solvophobic effect in this solution.

A Numerical Study of Vapor–Liquid Equilibrium in Binary Refrigerant Mixtures Based on 2,3,3,3-Tetrafluoroprop-1-ene

The binary refrigerant mixtures containing 2,3,3,3-Tetrafluoroprop-1-ene are considered as excellent substitutes for traditional refrigerants. Weak hydrogen bonds exist in hydrofluorocarbons and hydrofluoroolefins. However, for several recently published binary refrigerant mixtures, there is no Vapor–Liquid Equilibrium calculation study considering hydrogen-bonding associations. This work presents a calculation work of the saturated properties of nine pure refrigerants using the Cubic-Plus-Association Equation of State, considering the hydrogen-bonding association in refrigerant fluids. The average relative deviations of the saturated vapor pressure, liquid, and vapor density are less than 1.0%, 1.5%, and 3.5%, respectively. The Vapor–Liquid Equilibrium of ten binary refrigerant mixtures containing 2,3,3,3-Tetrafluoroprop-1-ene is also calculated using the Cubic-Plus-Association Equation of State with the van der Waals mixing rule. The average relative deviations of the liquid-phase and vapor-phase mole fractions are less than 1.0% and 2.0%, respectively. Moreover, the Vapor–Liquid Equilibrium data and the model’s adaptability are analyzed and discussed.

Atomic insights into the heterogeneity and the interface interactions of nanoconfined aqueous electrolyte solution

The structure and properties of nanoconfined electrolyte (nano electrolyte) solutions are important subjects in biochemistry, electrochemistry, separation science, etc. In the present work, neutron scattering and data driven reverse Monte Carlo were employed to quantitatively reveal the microstructure of aqueous CaCl2 solution in mesoporous silica MCM-41 at the atomic level. The electrolyte solution distributes in-homogeneously in the pores of mesoporous silica along the radial direction, which can be divided into the core, the transition, and the interface regions. The hydrogen bond structure of water in nano electrolytes is strengthened in the core region, analogous to that of nano water confined in nanochannels, and the ion association was enhanced in the transition region. The structure of the solution in the interface region was analogous to the bulk electrolyte solution under high pressure because of the confinement and interface effects. When the package ratio of nano electrolyte solution is insufficient, small amount of solution quasi-monolayer adsorb on the internal surface of mesoporous silica, the majority solution preferentially forms clusters with different sizes to adhere to the wetted interface. The anomalous hydrogen-bonding structure and ion association found in the present work improve our understanding of nanoconfined electrolyte solutions.

Simulation of multiphase behavior in supercritical CO2–heavy oil–water sludge extraction systems using Cubic-Plus-Association Equation of State

A new methodology was proposed for predicting the multiphase behavior of a supercritical CO2–heavy oil–water–solvent system during supercritical CO2 extraction. The cubic-plus-association equation of state (CPA EoS) was used to model the hydrogen bond association between asphaltene and water and to develop a nine-step characterization method for asphaltene-containing oil. Results showed that the proposed method could represent phase behavior for three equilibrium phases: the vapor phase and high-density and low-density liquid phases. The absolute average relative deviation between the predicted and experimental phase boundary pressures was 3.6–11.8%, smaller than those (7.0–20.8%) calculated using Soave–Redlich–Kwong EoS with Huron–Vidal mixing rules. Moreover, case studies on appropriate extraction conditions showed that the extraction pressure increased with increasing molecular weight and critical pressure of each pseudocomponent. Increasing extraction pressure for H2O-containing systems was beneficial for improving extraction efficiency.

Intrinsic Anti-Freezing and Unique Phosphorescence of Glassy Hydrogels with Ultrahigh Stiffness and Toughness at Low Temperatures.

Most hydrogels become frozen at subzero temperatures, leading to degraded properties and limited applications. Cryoprotectants are massively employed to improve anti-freezing property of hydrogels; however, there are accompanied disadvantages, such as varied networks, reduced mechanical properties, and the risk of cryoprotectant leakage in aqueous conditions. Reported here is the glassy hydrogel having intrinsic anti-freezing capacity and excellent optical and mechanical properties at ultra-low temperatures. Supramolecular hydrogel of poly(acrylamide-co-methacrylic acid) with moderate water content (≈50 wt.%) and dense hydrogen-bond associations is in a glassy state at room temperature. Since hydrogen bonds become strengthened as the temperature decreases, this gel becomes stronger and stiffer, yet still ductile, with Young's modulus of 900MPa, tensile strength of 30MPa, and breaking strain of 35% at -45°C. This gel retains high transparency even in liquid nitrogen. It also exhibits unique phosphorescence due to presence of carbonyl clusters, which is further enhanced at subzero temperatures. Further investigations elucidate that the intrinsic anti-freezing property is related to a fact that most water molecules are tightly bound and confined in the glassy matrix and become non-freezable. This correlation, as validated in several systems, provides a roadmap to develop intrinsic anti-freezing hydrogels for widespread applications at extreme conditions.

Impact-Protective Bicontinuous Hydrogel/Ultrahigh-Molecular Weight Polyethylene Fabric Composite with Multiscale Energy Dissipation Structures for Soft Body Armor.

Soft body armor greatly improves the comfort and security of the wearers. Although laminates based on high-performance fabrics have been adopted, it remains an enormous challenge to develop fabric laminates having flexibility, low bulge deformation, and ballistic protection capability simultaneously. Herein, we report a bullet-proof bicontinuous hydrogel (BH)/ultrahigh-molecular weight polyethylene fabric (UPF) composite. The presence of the BH significantly improves the impact resistance performance of the UPF, without compromising its flexibility. In specific, the multiscale energy dissipation structures composed of hydrogen bond associations in the chain scale, bicontinuous phase structures in the nanoscale, and fibers in the microscale are broken to dissipate energy. As a result, the impact energy of the bullet is greatly absorbed and the bulge height of the composites is significantly reduced in contrast to the neat UPF laminates. This study indicates that the flexible BH-UPF composites with multiscale energy dissipation structures have a promising application in soft body armor.

Electronic and Crystal Packing Effects in Terms of Static and Kinetic Force Field Features: Picolinic Acid N-Oxide and Methimazole

Herein, we experimentally obtained and studied the inner-crystal scalar potential fields and the associated vector force fields of static and kinetic nature in picolinic acid N-oxide (PANO) and methimazole. The “through-bond” and “through-space” electronic effects were defined and distinguished via the vector fields and concurred with the penetration of the electron contributor’s electrostatic and kinetic force field pseudoatoms (φes- and φk-basins) into the occupier’s chemical atom (ρ-basin). A special focus was given to the dipolar N+–O– bond as well as to the thioamide N–C═S and carboxylic O═C–OH fragments. An unusual way of interatomic charge transfer was revealed between two nonbonded hydrogen atoms [COO−]H···H[−C] in the PANO crystal. The experimental electric and kinetic force fields in the molecular crystals were compared to the theoretical ones for the free molecules and hydrogen-bonded associates, which helped figure out the natural consequences of the crystal packing effect. As expected, the appearance of neighboring attractors in a dense crystal packing requires zero-flux surfaces (ZFSs) emerging in the vector fields and the compression of the outer force field pseudoatoms of a molecule. We proposed to consider a ZFS in the kinetic force field to be a turning surface for electrons in the sense that an electron passed through the boundary is immediately affected by the redirected force attributed to another attractor. The strengthening and noticeable increase observed in the covalency of the intramolecular hydrogen bond O–H···O in the PANO crystal is a direct consequence of such compression of the hydrogen atom and pseudoatoms by the inner-crystal environment. The Pauli and fermionic scalar and vector fields were applied to locate electron lone pairs and describe their involvement in noncovalent interactions within the donor–acceptor mechanism.

ТЕОРЕТИЧЕСКОЕ ИССЛЕДОВАНИЕ АССОЦИАЦИИ АРИЛОВЫХ ПРОИЗВОДНЫХ МОЛОЧНОЙ КИСЛОТЫ

A theoretical study of the association of phenyl and ortho-substituted aryl derivatives of lactic acid was carried out. Two variants of hydrogen-bonded associates in the gas phase were calculated: non-classical, actually found in the crystals, and simulated classical dimers. The energy advantage of classical dimers and the non-equivalence of diastereotopic electron lone pairs at the carbonyl oxygen atom were shown.

Experimental study on sodium acetate trihydrate/glycerol deep eutectic solvent nanofluids for thermal energy storage

With the development of electronic machinery, the traditional heat exchange working fluid can no longer be used in some extreme working environments. As a new type of fluid, deep eutectic solvent has the advantages of promising thermal stability, low cost and non-toxicity through the hydrogen bond association of hydrogen bond acceptor and hydrogen bond donor, and is also coined to be an efficient heat transfer working fluid. In this work, three kinds of nanofluids filled with TiO2, Al2O3 and Fe2O3 nanoparticles were prepared with glycerol/sodium acetate trihydrate deep eutectic solvent as the base solution, and the mechanism of thermal conductivity change of nanofluids were discussed from atomic and microscopic levels. The experimental results showed that the prepared glycerol/ sodium acetate trihydrate 2:1 deep eutectic solvent system reduced the viscosity by 58.03% compared with glycerol, and increased the thermal conductivity by 17.2% compared with glycerol at 25 ℃. The effects of nanoparticles on thermal conductivity and specific heat capacity were also investigated. Compared with deep eutectic solvent, the thermal conductivity was improved after adding Fe2O3 nanoparticles; it is worth noting that the specific heat capacity of nanofluids was more than doubled after adding nanoparticles.

Experimental evidence and computational results in the investigation of thermodynamic properties and molecular structure of hydrogen-bonded cyclohexylamine and ethyl methyl ketone system

Combining experimental and computational study is a fundamental and attractive method for analyzing intermolecular hydrogen bonds and specific interactions in binary mixtures of different liquids. An experimental and computational investigation of the structural interactions between the molecules of cyclohexylamine and ethyl methyl ketone (EMK) is presented. In the experimental part of the work, the density of mixtures of cyclohexylamine and EMK in the specific mole fractions is reported at 298.15, 303.15, 308.15, and 313.15 K and at an absolute pressure of 86.7 kPa. Densities data have been used to evaluate the excess molar volumes, the thermal expansion coefficients, and the isothermal coefficient of pressure excess molar enthalpy. The Jouyban–Acree model has been used for mathematical correlation of the densities. Using the Redlich-Kister equation, the results of excess molar volumes were fitted. Through computational technics such as density functional theory (DFT), quantum theory of atoms in molecules (QTAIM), and also molecular dynamics (MD) simulations, the analysis of intermolecular hydrogen-bonded associations has been accomplished. MD simulations computed density and radial distribution functions (RDFs) in the liquid phase at 298.15 K and at 1 atm.

Improvement of structural characteristics and in vitro digestion properties of zein by controlling postharvest ripening process of corn

The newly harvested corn was stored at constant temperature (15 and 25 °C) and relative humidity (55%). The structural characteristics and in vitro digestion properties of zein as well as their structure-function relationship during postharvest ripening of corn were analyzed. The free sulfhydryl content and surface hydrophobicity decreased and the disulfide bonds and absolute value of ζ-potential increased during postharvest ripening of corn for 56 days at two storage temperatures. The particle size and polydispersity index reached the minimum values when postharvest ripening for 28 days. The association of hydrogen bonds for zein was decreased and more β-sheets were transformed into random coils in the postharvest ripening period, leading to the reduction in thermal stability and enthalpy change of zein. In addition, the molecular weight of α-zein decreased when postharvest ripening at 15 °C for 28 days, and changed little during postharvest ripening at 25 °C. In vitro simulated digestion experiment proved that the maximum degree of hydrolysis of zein was appeared when postharvest ripening for 28 days at both two storage temperatures, which was higher at 15 °C than at 25 °C. This indicated that appropriate postharvest ripening behavior could improve the digestibility of zein. The reduction of protein aggregation extent and thermal stability as well as enhanced disordered secondary structure of zein might be important factors to improve its digestibility during the postharvest ripening. The results suggested that controlling the postharvest ripening process of corn could modify the structure of zein and improve its digestion properties. • Postharvest ripening of corn was performed at constant temperature and humidity. • Aggregation, thermal stability and ordered secondary structure of zein reduced. • Degree of hydrolysis for zein was highest by postharvest ripening for 28 days. • Improvement of zein digestibility was related to its structural modification. • Controlling postharvest ripening process of corn improved digestion property of zein.

Structural Characterization, Rheological Properties, Antioxidant and Anti-Inflammatory Activities of Polysaccharides from Zingiber officinale.

The structural characteristics, rheological properties, antioxidant and anti-inflammatory activities of Zingiber officinale polysaccharides (ZOP) and ZOP-1 were studied. The total soluble sugar contents of ZOP and ZOP-1 were 78.6 ± 0.6 and 79.4 ± 0.4%, respectively. Compared with ZOP, ZOP-1 had a larger molecular weight and a more uniform distribution. There were also some differences in the monosaccharide composition between ZOP and ZOP-1. The main monosaccharide of ZOP and ZOP-1 was glucose (Glc) and galactose (Gal), respectively. Ultraviolet visible spectroscopy (UV-Vis) and fourier transform infrared spectra (FT-IR) results showed that the two polysaccharides had the characteristic absorption peaks of polysaccharides and did not contain nucleic acid and protein. They had good thermal stability, trihelix structure and amorphous sheet structure. ZOP and ZOP-1 had obvious differences in microstructure. The surface of ZOP was smooth and the broken structure was compact and stable with angular shape, while the surface of ZOP-1 was uneven with spiral accumulation and not closely arranged. Moreover, ZOP and ZOP-1 were polysaccharides molecular polymers which were entangled by van der waals' force (VDW) between polysaccharides molecules and hydrogen bond association between sugar chains, and both contain α pyranose. At different concentrations, temperature, pH and salt ion concentrations, both ZOP and ZOP-1 had the properties of non-Newtonian fluids, showed shear dilution phenomenon, which had the potential as a texture modifier or thickener in food or biomedicine. Compared with ZOP, ZOP-1 showed superior antioxidant and anti-inflammatory activities in vitro.

Influence of Polymer Polarity and Association Strength on the Properties of Poly(alkyl ether)-Based Supramolecular Melts

The present work focuses on the impact of polymer polarity and hydrogen-bonding (H-bonding) end groups association strength on the structure and dynamics of poly(alkyl ether)-based supramolecular model polymers studied by means of small angle scattering (SAS), rheology, dielectric relaxation spectroscopy (DRS), and differential scanning calorimetry (DSC). These consist of poly(propylene oxide) (PPO) or poly(ethylene oxide) (PEO) backbone that self-assembly in the bulk via hydrogen bonding (H-bonding). Diaminotriazine (DAT) and thymine-1-acetic acid (THY) as well as 2-ureido-4[1H]-pyrimidinone (UPY) are the H-bonding end groups of choice. Both PPO and PEO bearing either DAT or THY as end groups associate into linear chains, but PPO-THY/DAT forms longer chains in comparison with PEO-THY/DAT. The lower polarity of the backbone results in stronger associations for the same end groups. However, the temperature dependence of the association/dissociation lifetimes for this H-bonding type is independent of the different main chain polarity as these breaking times do not exceed the rouse chain dynamics as expected within the Cates model. PPO-UPY forms a transient network characterized by the interplay between small transient bonds controlled by the characteristic times of association/dissociation between pairs of UPY groups involving probably just two ends, revealed by the similar dielectric spectra with PPO backbone, and a more stable bond type of associate that forms phase separated UPY clusters. The latter are responsible for the physical cross-links in the network and result in the rubbery-like plateau of the rheological spectra. PPO-UPY has similar structure to PEO-UPY, as validated by small angle scattering, but the UPY detachment times in the clusters are longer for PEO-UPY than for PPO-UPY, though the activation energies are very close and match the typical energy barrier specifically imposed by the hydrogen bonds. Moreover, while the segmental relaxation times and the glass transition temperature (Tg) of PPO-UPY is similar to PPO, PEO-UPY has the highest Tg value and a much slower segmental relaxation as compared to PEO and PPO based supramolecular polymers. This seems to indicate that the H-bonding association dynamics of the UPY groups is strongly influenced by the main chain polarity that play a fundamental role in defining the time scale of the association process.

Insight into the weak interaction between organic primary amine and propionic acid or phenol solvents in solvent extraction

The essence of solvent extraction is to change the interaction degree between extracted molecules and solvents in the system. The study of solvent extraction at the molecular level has important guiding significance for further design. Here, taking the extraction of organic weak acid (phenol/propionic acid) by primary amines N1923 through hydrogen bond association as an example, the quantitative calculation parameters of reactive molecules were discussed, such as the charge distribution, potential distribution, average local ionization energy (ALIE) distribution and abbreviated Fukui function, while the polar index and polar area percentage were calculated. Moreover, the region and intensity of weak interaction were analyzed and visualized by electronic density difference and Van der Waals (VDW) radius. At the same time, the electron density of the critical point of bond (BCP) and the corresponding predicted value of hydrogen bonding energy are calculated. Finally, the solubility energy of primary amines and the Gibbs free energy of extraction reaction were calculated, and the results show that the interaction between organic amine and propionic acid is stronger by the hydrogen bond mechanism. This study provides a set of systematic cases to analyze the interaction between extraction molecules. It provides a new perspective for understanding the essence of solvent extraction, thus promoting the theoretical development of separation science.