Effect Of Solvent Polarity Research Articles

Waugh Type Polyoxometalate Enneamolybdomangate(IV) as an Acid Catalyst for Hydrolysis and as an Oxidant for Aspirin: A Kinetic Study

The oxidations of aspirin and salicylic acid by enneamolybdomanganate(IV) were studied in perchloric acid medium. The aspirin undergo hydrolysis prior to the oxidation to generate salicylic acid, which was found to be catalyzed by both HClO4 as well as the oxidant. The rate of hydrolysis of aspirin catalyzed by the oxidant was found to be lesser than that of HClO4. A mechanism based on the kinetic results is proposed for oxidation of both aspirin and salicylic acid. Initially, aspirin undergo hydrolysis to give salicylic acid, which is catalyzed by both the oxidant, which also acts as an acid catalyst and the HClO4 used. The salicylic acid generated in prior hydrolysis reacts with an oxidant undergoing oxidative decarboxylation by enneamolybdomanganate(IV) in a rate determining step generating phenol. Further oxidation of phenol by another oxidant molecule gives the final product p-benzoquinone in a fast step. The mechanism of oxidation of salicylic acid was also studied under identical conditions as that of aspirin and found to be similar except its prior hydrolysis. A plausible mechanism was proposed and the rate laws for both the substrates were derived. In order to understand the intervention of free radicals the reaction was studied in presence of added acrylonitrile. The formation of copious precipitate due to polymerization of added acrylonitrile was not observed and the values of kobs also remain constant in presence of added acrylonitrile. The formation of MnIII was also studied in presence of added tetrasodium pyrophosphate, which did not affect the values of kobs. Therefore, the formation of free radical and MnIII was excluded while proposing mechanisms for both the substrates. The effect of added products Mn2+ and molybdate also did not have any effects indicating no prior equilibria involving these two products. The effect of ionic strength and solvent polarity are in favour of the reaction between two neutral molecules. The activation parameters were determined and support an outer sphere reaction with formation of a weak precursor complex between the reactants was proposed for both aspirin and salicylic acid.

Extraction Effect of Polar and Non-Polar Solvents on the Physio Chemical Characteristics of Flaxseed Oil

ABSTRACT: Flax seed oil is a vegetable oils with a rich source of fatty acids especially omega-3-fatty acid α-linolenic acid. Extraction of flaxseed oil employes many techniques including solvent extraction. The present work estimated the effect of a total of six solvents, both polar and non-polar on the physio-chemical characteristics of flax seed oil. Amongst the polar solvents, isopropanol showed better iodine value and DPPH free radical scavenging values. Overall, hexane showed the highest oil content of 45% (w/w). This study indicated that hexane a non-polar solvent showed the most efficient indicators in terms of iodine value (IV) (25.3 ± 0.41 iodine/ 100 g oil), peroxide value (PV) (21.2 ± 0.7 meq KOH/kg), saponification value (SV) (203.0 mg KOH/g oil) as well as DPPH free radical scavenging activity at 76.7 ± 2.32 % compared to the other polar solvents.

Experimental and Theoretical Insights into a Novel Lightfast Thiophene Azo Dye

Thiophene ring-enhancing electron delocalization imparts unique properties to azoic chromophore tools. The novel TA-OH dye contains a push–pull π-electron system, including a thiophene-azo scaffold with a hydroxyl group at the ortho position to the azo bridge. The hydroxyl group is expected to lock the azo bridge in its trans conformation, concurring with the photostability and fastness of the dye. The single crystal analysis identified the molecule’s primary conjugation plane, and the theoretical analysis provided electronic pattern insights. The absorption behavior and the trans-to-cis conversion were examined from both experimental and theoretical perspectives. The effect of solvent polarity and the role of pH on the photophysical properties were explored. The solvent polarity strongly affects the absorbance spectrum of TA-OH, therefore potentially making NLO active. Additionally, TA-OH exhibited pH responsiveness akin to classic dichromatic pH indicators, with a noticeable color shift from red to blue observed as pH transitioned from neutral to alkaline. Absorbance titration experiments, along with experimental/theoretical determination of pKa, defined the pH sensing ability.

Redox-Mediated Enantioselective Interactions in Chiral Metallopolymers Possessing Supramolecular Chirality

Synthetic chiral platforms can be a powerful platform for enantioselective interactions, especially when coupled with redox-mediated electrochemical processes. Redox metallopolymers represent a distinct class of versatile functional materials and have been extensively studied for a wide scope of applications such as membranes, self-assembly, hydrogels, and redox-mediated ion separation. However, many studies have focused on molecularly-selective binding and release of achiral molecules, with limited studies on chirality strategies for enantioselective interactions. Chiral organic anions comprise an important class of biologically-relevant molecules, and their separation and sensing have received intense attention. Here, we introduce new chiral redox-polymers with chiral ferrocene (Fc) building blocks, that can serve as an electro-responsive enantioselective platform for a variety of amino acids and pharmaceutical carboxylates, taking advantage of supramolecular chirality for enhancing electrochemical recognition. Two chiral redox-metallopolymers were designed and synthesized based on Ugi’s amine-inspired chiral monomers containing an amide (poly-1) or amine group (poly-2), and their enantioselective recognitions toward amino acids and pharmaceutical carboxylates were investigated by redox potential shifts using square wave voltammetry. The half potential shift of both poly-(S)-1 and poly-(S)-2 increased more with increasing D-tryptophan concentration than the other enantiomer, L-tryptophan, while the half potential of poly-(R)-1 and poly-(R)-2 shifted more with L-tryptophan than with D-tryptophan, proving the enantioselective interaction of both redox-metallopolymers. Nuclear Overhauser Effect spectroscopy (2D NOESY) and solid-state circular dichroism revealed the emergence of supramolecular chirality of the polymers resulting from the intramolecular interaction between the ferrocene and the alkyl group in the backbone, and the steric hindrance of the ferrocene within the polymer. The half-peak potential shift demonstrated the remarkable enhancement of enantioselective recognition with tryptophan (Trp) and naproxen, provided by the chiral polymers possessing the supramolecular chirality over the single-site, chiral building block itself. For instance, the two (S) polymers showed the potential shift difference 2.4-2.8 times higher than the corresponding monomers upon the binding of Trp enantiomers. The enantioselective potential shift of the chiral metallopolymer electrodes could determine enantiomeric excess (%ee) of Trp over the range of 0–100%ee. Investigation on solvent polarity and pH effect revealed that the enantioselective mechanism of the chiral redox polymers was attributed to the subtle balance between hydrogen bonding and π-π interaction. We also identified the importance of aromatic groups on the analytes for increasing enantioselectivity of the chiral redox polymers. This work highlights the potential of chiral redox-metallopolymers as platforms for electrochemically-modulated enantioselective processes toward a variety of amino acids and pharmaceutical carboxylates. Figure 1

Synthesis, Computational and Antimicrobial Study of 2-(2-Hydrazinyl)thiazole Derivatives

In the present investigation, we report a combined computational and experimental study of eight thiazole derivatives (4a-4h) obtained from 3,4-dihydronaphthalen-1(2H)-one. A green chemistry protocol comprising PEG-400 and sulfamic acid was employed for the synthesis of eight diverse thiazole derivatives from 3,4-dihydronaphthalen-1(2H)-one, thiosemicarbazide and various phenacyl bromides. The synthetic strategy provides benefits like short reaction time, high yield, and non-chromatographic purification. The compounds were structurally confirmed on the basis of IR, 1HNMR and 13C NMR. The obtained thiazole derivatives were studied using the density functional theory (DFT) method employing B3LYP/6-311G(d,p) level of theory for optimization and Time-Dependent DFT (TD-DFT) approach for examining electronic energies and UV-Vis characteristics. Various computational parameters like bond length, bond angles, HOMO, LUMO, MESP, Mulliken charges, and global descriptors are obtained and discussed. The UV-Vis study the in gas phase and DMSO solvent was investigated to obtain various insights such as absorption energies oscillator strength, configurations and transitions of examined thiazole derivatives. The effect of polar solvent has augmented the absorption wavelength of all studied thiazole derivatives. The experimental and simulated UV-Vis data correlate with each other prompting the effectiveness of the computed method. The scaled and experimental wavenumbers provided the appropriate assignment of various vibrational signals. The antibacterial study was performed against E. coli, P. aeruginosa, and S. aureus which demonstrated the strong antibacterial potential against S. aureus. The antifungal study against C. albicans revealed that these compounds are poor antifungal agents. The DPPH and OH radical assays were used to establish the % radical scavenger effects and results showed that these derivatives are good antioxidant agents. The % hemolytic activity of the tested compounds showed that all compounds fall within the acceptable toxicity limit. Importantly in slico ADME and toxicity prediction studies of these compounds highlighted good ADME profile with no hepatotoxicity, immunotoxicity and cytotoxicity.

Finding the right balance between tertiary amine steric effect and solvent polarity for the regioselectivity and kinetics of epichlorohydrin acetolysis

AbstractThe asymmetric oxirane ring‐opening reaction leading to the formation of regioisomeric chlorohydrin esters was studied in the reaction series “acetic acid–epichlorohydrin–tetrahydrofuran (nitrobenzene)–trialkylamine” by kinetic methods and FT‐IR spectroscopy. The effect of solvent polarity and the structure of tertiary amines on the regioselectivity and reaction rate were studied. Tertiary amines with comparable basicity but different nucleophilicity and spatial structure were chosen as catalysts. It was shown that in solvents of different polarity, the components of the initial reaction system are present both as hydrogen‐bonded complexes and as individual substances. The reaction orders with respect to acid and amine in solvents of different polarity were established. Correlations between the reaction rate and the parameters of nucleophilicity and structure of amines as well as the polarity of the solvent were established. The regioselectivity of the reaction was studied by 1H NMR spectroscopy using the ratio of regioisomeric reaction products. It was shown that the regioselectivity and rate of catalytic acetolysis of epichlorohydrin are effectively controlled by the structure of tertiary amines and the polarity of the solvent. The scheme of reaction regio‐flows was detailed.

Investigation of the Effect of Solvents on the Synthesis of Aza-flavanone from Aminochalcone Facilitated by Halogen Bonding.

It has been recognized that CBr4 can give rise to a noncovalent interaction known as halogen bond (XB). CBr4 was found to catalyze, in terms of XB formation, the transformation of 2'-aminochalcone to aza-flavanone through an intramolecular Michael addition reaction. The impact of XB and the resulting yield of aza-flavanone exhibited a pronounced dependence on the characteristics of the solvent. Notably, yields of 88% in ethanol and 33% in DMSO were achieved, while merely a trace amount of the product was detected in benzene. In this work, we use a computational modeling study to understand this variance in yield. The reaction is modeled at the level of density functional theory (based on the M06-2X exchange-correlation functional) with all-electron basis sets of triple-ζ quality. Grimme's dispersion correction is incorporated to account for the noncovalent interactions accurately. Harmonic frequency calculations are carried out to establish the character of the optimized structures (minimum or saddle point). Our calculations confirm the formation of an XB between CBr4 and the reacting species and its role in lowering the activation energy barrier. Stronger orbital interactions and significant lowering of the steric repulsion were found to be important in lowering the activation barrier. The negligible yield in the nonpolar solvent benzene may be attributed to the high activation energy as well as the inadequate stabilization of the zwitterionic intermediate. In ethanol, a protic solvent, additional H-bonding contributes to further lowering of the activation barrier and better stabilization of the zwitterionic intermediate. The combined effects of solvent polarity, XB, and H-bond are likely to give rise to an excellent yield of aza-flavanone in ethanol.

Effect of solvent polarity on the performance of thermally activated delayed fluorescence OLEDs

Molecular orientation in organic light-emitting diodes (OLEDs) is now regarded as an important factor that affects device efficiency. Herein, different polarity solvents were used to investigate the effect of solvent polarity on the molecular orientation and optoelectronic characteristic of spin-coated thermally activated delayed fluorescence (TADF) molecules. The lower solvent polarity is beneficial to enhance the photoluminescence (PL) intensity, photoluminescence quantum yield (PLQY) and the horizontal orientation of the emission molecule. And the higher horizontal orientation ratio promoted the carrier transport measured from the single carrier devices. The optimized performance of the OLEDs was obtained in the OLEDs based on the spin-coated emission layer with lower polarity solvent. The combined effect of PLQY, horizontal orientation ratio, surface morphology, and carrier mobility of the EMLs was ascribed to the enhancement of OLEDs. It indicates that optimizing the solvent polarity is an effective way to enhance the performance of solution processed OLEDs.

Long-Lived Charge-Separated State in Naphthalimide-Phenothiazine Compact Electron Donor-Acceptor Dyads: Effect of Molecular Conformation Restriction and Solvent Polarity.

To study the charge separation (CS) and long-lived CS state, we prepared a series of dyads based on naphthalimide (NI, electron acceptor) and phenothiazine (PTZ, electron donor), with an intervening phenyl linker attached on the N-position of both moieties. The purpose is to exploit the electron spin control effect to prolong the CS-state lifetime by formation of the 3CS state, instead of the ordinary 1CS state, the spin-correlated radical pair (SCRP), or the free ion pairs. The electronic coupling magnitude is tuned by conformational restriction exerted by the methyl groups on the phenyl linker. Differently from the previously reported NI-PTZ analogues containing long and flexible linkers, we observed a significant CS emission band centered at ca. 600 nm and thermally activated delayed fluorescence (TADF) with a lifetime of 13.8 ns (population ratio: 42%)/321.6 μs (56%). Nanosecond transient absorption spectroscopy indicates that in cyclohexane (CHX), only the 3NI* state was observed (lifetime τ = 274.7 μs), in acetonitrile (ACN), only the CS state was observed (τ = 1.4 μs), whereas in a solvent with intermediate polarity, such as toluene (TOL), both the 3NI* (shorter-lived) and the CS states were observed. Observation of the long-lived CS state in ACN, yet lack of TADF, confirms the spin-vibronic coupling theoretical model of TADF. Femtosecond transient absorption spectroscopy indicates that charge separation occurs in both nonpolar and polar solvents, with time constants ranging from less than 1 ps in ACN to ca. 60 ps in CHX. Time-resolved electron paramagnetic resonance (TREPR) spectra indicate the existence of the 3NI* and CS states for the dyads upon photoexcitation. The electron spin-spin dipole interaction magnitude of the radical anion and cation of the CS state is intermediate between that of a typical SCRP and a 3CS state, suggesting that the long CS-state lifetime is partially due to the electron spin control effect.

Computational Insights into the Reactivity Difference between Hypervalent Bromine(III) and Hypervalent Iodine(III) Reagent in the C−H Amination and Alkene Aziridination

AbstractWe present herein a computational exploration into the mechanism and origin of the reactivity difference between N‐triflylimino‐λ3‐iodane and N‐triflylimino‐λ3‐bromane in the C−H amination and alkene aziridination. Our calculations revealed that the preferred mechanism for C−H amination involves the generation of free nitrene intermediate, while the alkene aziridination proceeds via a concerted reaction mechanism. The superior reactivity of N‐triflylimino‐λ3‐bromane over N‐triflylimino‐λ3‐iodane could be mainly ascribed to better nucleofugality of the bromanyl moiety, which can be characterized by the strength of I−N and Br−N bond. The effect of solvent polarity on the reactivity of N‐triflylimino‐λ3‐bromane as a nitrene precursor will be discussed.

Effect of Solvent Polarity on Fabrication of Dual Janus Particles with Asymmetric Morphology and Chemical Identity via Photo-initiated Seeded Swelling Polymerization

Particles with asymmetric morphology or surface chemical identity (Janus) are of great interest in the field of materials due to their special composition and structure. However, it is still a challenge to prepare particles with dual asymmetry via simple and convenient synthesis strategies. Herein, micron-sized dual-asymmetry Janus particles were prepared via photo-induced seeded swelling polymerization within 30 min. By controlling the polarity of the organic solvent (porogenic reagent), Janus particles with various morphologies were fabricated. The particles with convex surfaces, such as dumbbell-shaped, snowman-shaped, and golf-shaped morphologies, were obtained in the polar porogenic system, while the concave surface particles, such as bowl-shaped and ball-in-bowl, were acquired in the non-polar porogenic system. Mushroom-shaped and pinecone-shaped particles were generated in the binary porogenic system. Particularly, snowman-shaped, bowl-shaped, and pinecone-shaped particles were characterized by confocal laser scanning microscopy, exhibiting asymmetric chemical identity. They could be easily modified into amphiphilic solid surfactants for emulsifying oil–water incompatible mixtures with a definite interfacial orientation. This strategy provides a possibility for the simple and rapid preparation of dual Janus particles with asymmetric morphology and chemical identity, which are expected to be produced on a large scale.

A thermodynamic relationship between the chemical equilibrium constant and the dielectric properties of the reaction medium: Solvent mixtures and universal solvents.

We introduce a novel thermodynamic model oriented toward accurately predicting the effect of solvent polarity on chemical equilibrium. Our approach is based on the fundamental principles of thermodynamics of continuum medium and can be applied generally to estimate the Gibbs free energy contribution resulting from electrostatic interactions between the solvent and chemical species to the corresponding equilibrium constant in the solution phase. Using a set of assumptions, we have developed a practical calculation methodology that employs multivariate fitting to determine the dependence of 27 different reactions, including tautomerizations, dimerizations, and acid-base dissociations, on solvent polarity. From this approach, we estimated all the contributions to the Gibbs free energy of reaction in the solution phase of some of these processes, including the gas phase Gibbs free energy of reaction, the electrostatic (continuum) contribution to the solvation Gibbs free of the involved solutes and, even, the Gibbs free energy contribution due to specific (intramolecular) solute-solvent interactions, albeit indirectly.

Selective control of donor-acceptor Stenhouse adduct populations with non-selective stimuli

Selective control of donor-acceptor Stenhouse adduct populations with non-selective stimuli

Theoretical study on ESIPT mechanism and negative solvatochromism effect of 3-(4,5-Diphenyl-1H-imidazol-2-yl)-9-phenyl-9H-carbazol-4-ol compound in different solvents

It is necessary to study the excited-state intramolecular proton transfer of complex molecular systems in solvents, which play important roles in photochemistry, photobiology, and optoelectronic materials. In this work, we have worked on the effect of solvent polarity on the ESIPT behaviour of 3-(4,5-Diphenyl-1H-imidazol-2-yl)-9-phenyl-9,9a-dihydro-4aH-carbazol-4-ol (CHPI). Specifically, an in-depth study of hydrogen bonding behavior and charge complexation in different polar solvents has confirmed the excited state hydrogen bonding enhancement mechanism, which is the primary prerequisite to facilitate the ESIPT process. It is noteworthy that the intramolecular hydrogen bonding of CHPI compound is enhanced more significantly in nonpolar solvents. To further elaborate the ESIPT process, we analyzed the potential energy curves of the S0 and S1 states, and the comparison shows that the potential barrier decreases as the solvent polarity decreases. Therefore, the nonpolar solvent environment is more favorable for CHPI molecule to undergo the ESIPT process.

Nucleophilic epoxide ring opening in the system "epichlorohydrin–carboxylic acids–tetrabutylammonium iodide–solvent (e=15.1–28.7)"

The mechanism of the oxirane ring opening by carboxylic acids with different volume of substituents in the system "epichlorohydrin(ЕCH)–RCOOH–tetrabutylammonium iodide–solvent (=15.1–28.7)" was studied in the excess of ECH at the temperatures of 40–800C by methods of chemical kinetics and correlation analysis. The effects of solvent polarity (ECH and its mixtures with THF and nitrobenzene), temperature, and spatial structure (topological steric effect index TSEI) of carboxylic acids on the proceeding of the reaction were investigated. The structure of the reaction products was determined by gas chromatography–mass and 1H NMR spectroscopy. It was found that the reaction accelerates with a decrease in the solvent polarity, an increase in temperature and steric effect in the structure of the reagent. It was shown that the tetraalkylammonium carboxylate (R'4N+–OOCR) which formed in situ causes the final product formation in the rate-determining step of the reaction mechanism.

Theoretical Explorations of Structural, Electronic, and Spectroscopic Properties of a Series of Ruthenium Schiff-Base Complexes

The present work concentrates on theoretical investigations of the substituent effects on the reactivity, electronic properties, and UV-vis spectra of a series of ruthenium-Schiff base complexes using density functional theory (DFT). Four complexes are studied herein, where N-(2¢-hydroxyphenyl)benzaldimine is the Schiff base differing in the para-substituent (R) on the benzaldehyde fragment (R = CH3, H, Cl, CF3). B3LYP/SDD-6-31G(d,p) level of theory has been used for computational studies (Gaussian 16). All the structures have been optimized, and the compositions of the frontier molecular orbitals have been analyzed. The energies of HOMO and LUMO and the global indices parameters have been calculated, which reveals that [Ru(PPh3)2(CO)(L-CF3)] is the most reactive complex and [Ru(PPh3)2(CO)(L-Cl)] the least. Time-dependent density functional theory (TDDFT) has been performed to study the electronic absorption parameters. The effect of solvent polarity upon absorption spectra has also been observed. It is found that the lowest energy absorptions in all the complexes show a blue shift with the increase in polarity of the solvent. Natural bond orbital (NBO) analysis of the complexes has been conducted to examine the charge distribution on the donor and the acceptor atoms along with their variation with change in the para-substituent.

Insights into photo‐induced excited state intramolecular proton transfer behavior for the novel 2‐([1, 1′‐biphenyl]‐4‐yl)‐3‐hydroxy‐4H‐chromen‐4‐one system: Effects of solvent polarity

AbstractIn the light of potential applications for detecting cysteine in vitro and in vivo, 2‐([1, 1′‐biphenyl]‐4‐yl)‐3‐hydroxy‐4H‐chromen‐4‐one (B‐bph‐fla‐OH) is explored about its excited state behaviors. Solvent‐polarity‐related photo‐induced hydrogen bond of B‐bph‐fla‐OH indicates nonpolar aprotic solvents largely enhance S1‐state hydrogen bonding interactions. Charge reorganization stemming from photoexcitation and polarity‐dependent energy gap between HOMO and LUMO orbitals further reveals the excited state intramolecular proton transfer (ESIPT) tendency. Insights into potential energy curves along ESIPT paths in solvents with different polarities and emission spectral behaviors of proton‐transfer tautomer, we present solvent polarity could harness the excited state behaviors for B‐bph‐fla‐OH system.

Effect of polar solvent on the efficiency of phenolic compounds and antioxidant potency of the lavender wild growing in Tunisia

A highest polar solubility of phenolic and flavonoids compounds of Lavandula stoechas required the use of appropriate solvent during extraction process. Extraction following an increase ingredient of polarity revealed that the chloroform seems as the best solvent able to release polyphenols followed by the ethyl-acetate. Total phenolic and flavonoids extracted with chloroform were respectively, 282.7 mg Eq GAE/g DW and 125.91 mg Eq QE/g DW. Even for the tree other solvents obtained results showed importance richness of the lavender on polyphenols. Amounts were correlated to the highest antioxidant potency approved. Main functional groups were detected and identified by Fourier transform infrared spectrophotometer (FTIR). Results give to the studied species an important alternative as a promising ecological natural source of bioactive antioxidant compounds and to be incorporated in food, pharmaceutical and cosmetics manufactures.

Chiral Metallopolymers for Redox‐Mediated Enantioselective Interactions

AbstractSynthetic chiral platforms can be a powerful platform for enantioselective interactions, especially when coupled with redox‐mediated electrochemical processes. While metallopolymers are versatile platforms for molecularly selective binding, their application for chiral applications is limited. In particular, the recognition and separation of biologically relevant chiral molecules can be key for biomanufacturing and diagnostics. Here, the design of chiral redox‐polymers enables electrochemically‐controlled enantioselective interactions, and supramolecular chirality is leveraged for enhancing recognition towards target enantiomers. Chiral redox‐metallopolymers are synthesized based on Ugi's amine‐inspired chiral monomers, and their enantioselective recognition toward ionic enantiomers such as tryptophan and naproxen is demonstrated, with higher enanhcement provided by the chiral redox‐polymer over the single‐site, chiral building bloack itelf. 2D nuclear magnetic resonance spectroscopy and solid‐state circular dichroism support the emergence of supramolecular chirality resulting from the intramolecular interaction between the ferrocene and the alkyl group in the backbone. The half potential shift of the redox‐polymers behaves linearly from 0% to 100%ee l‐tryptophan to enable enantiomer quantification. Investigation on solvent polarity and pH effect reveal that the enantioselective mechanism is attributed to the subtle balance between hydrogen bonding and π–π interaction. This study highlights the potential of chiral redox‐metallopolymers as platforms for electrochemically‐modulated enantioselective interactions towards a range of amino acids and pharmaceutical carboxylates.

Impact of solvent polarity on the morphology, physicochemical properties, and digestibility of A-type resistant starch particles

Resistant starch particles (RSP) formed by antisolvent precipitation method has attracted much attention as a functional food ingredient having beneficial effects on obesity and diabetes. However, the effect of solvent polarity on the physicochemical properties and digestibility of RSP remains unclear. Here, n-propanol, isopropanol, acetone, and ethanol were employed as antisolvents to prepare RSP. The width and length of the resulting RSP decreased from 0.87 μm to 0.59 μm and from 2.56 μm to 1.31 μm, respectively, upon increasing the solvent polarity, while dramatically decreasing their crystallinity and the gelatinization enthalpy from 80.5% to 62.3% and from 67.9 ± 14.4 J/g to 41.5 ± 8.3 J/g, respectively, suggesting that solvent polarity is critical factor determining morphology, crystallinity, and thermostability of RSP. Furthermore, the level of resistant starch in RSP was found to be inversely proportional to the degree of solvent polarity, which would provide a useful means for modulating the digestibility of RSP.