Solubility In Acetone Research Articles

Performance of a novel cobalt phthalocyanine sulfonamide‐based catalyst for oxidative desulphurization of gas condensate

AbstractSulphur compounds and mercaptans in gas condensate cause corrosion problems, poison catalysts in catalytic processes, and have adverse environmental impact through SOx emission upon combustion. Therefore, it is essential to remove sulphur and mercaptan from gas condensate to standard levels. In this study, the oxidative desulphurization (ODS) process in the presence of a cobalt phthalocyanine sulfonamide‐based catalyst was investigated. The homogeneous catalyst containing 23 wt.% active material was used and optimum operating conditions of temperature, volume ratio of caustic to gas condensate, caustic concentration, and solvent amount were determined to decrease sulphur content to less than 500 ppm and mercaptan to less than 200 ppm. The catalyst consumption in all experiments was kept constant at a minimum level (0.01 g/400 mL gas condensate). Results showed that this catalyst improved the reaction rate in the lower temperature and lower caustic to feed ratio and lower caustic concentration. The maximum sulphur removal was obtained at 5°C and 4 vol.% of caustic to gas condensate ratio at 16.7 wt.% of caustic concentration. Moreover, this catalyst improved sulphur removal from the gas condensate to about 5% compared to caustic sweeting without catalyst. Sulphur compounds had higher solubility in acetone rather than methanol, and sulphur removal by acetone was 96% while it was 91% for methanol. Finally, the economical and acceptable solvent for sulfoxides removal was methanol with 5% volume fraction.

Synthesis of cellulose nitrates from Miscanthus × giganteus var. KAMIS cellulose obtained under pilot production conditions

The work is devoted to the study of a novel national raw material resource Miscanthus × Giganteus var. KAMIS, which is positioned as one of the most promising natural sources for obtaining high-quality cellulose for the purpose of its further chemical functionalisation. A batch of technical cellulose isolated from raw materials under pilot production conditions using the nitric acid method having a cellulose content of 50.2% was characterized by high α-cellulose mass fraction (92.8%) and degree of polymerisation (1200) values. On the basis of the pilot batch of technical cellulose, a sample of cellulose nitrates offering basic functional properties was obtained: mass fraction of nitrogen – 11.18%; viscosity – 48 MPa·s; solubility – 94%. The synthesised sample is characterized by extremely high solubility in acetone, confirming the production of cellulose nitric acid esters, and a high yield of 150%. IR-Fourier spectroscopy was used to identify the main functional groups in the experimental batch of technical cellulose (3384, 2902, 1639, 1428, 1370, 1319, 1161, 700–500 cm-1) and in a sample of cellulose nitrates (1659, 1278, 834, 746, 683 cm-1). Acorresponding affiliation to cellulose and cellulose nitric acid esters was established. The structural and morphological features of the fibres of the experimental batch of technical cellulose and a sample of cellulose nitrates were characterised using scanning electron microscopy. Combined methods of thermogravimetric and differential thermal analyses were used to establish high initial temperature (197 °C) and specific heat of decomposition (6.92 kJ/g) values at the beginning of intensive decomposition. The obtained results substantiate the possibility to chemically functionalise cellulose isolated from a new alternative source into cellulose nitric acid esters with satisfactory functional properties.

Coating Properties of UV Curable Coatings on Natural Nails: Impact Evaluation of 5 Different Acrylate Monomers

Compositions on natural nails mostly contain acrylic monomers, more often 2-hydroxyethyl methacrylate (HEMA). These systems have been considered to be a potent sensitizer in contact with the skin. The purpose of the study was to compare five acrylic monomers: HEMA (hydroxyethyl methacrylate), HPMA (hydroxypropyl methacrylate), IBOMA (isobornyl methacrylate), MEP (methacryloylethylphosphate) and TMPTMA (trimethylpropane trimethacrylate) to find the substitute to HEMA. In this study, we explored the rheological and polymerization properties of uncured systems containing five acrylate monomers. Mechanical and adhesion properties were evaluated of cured compositions. Optimal criteria of compositions and cured coatings were defined, and tests were performed to find the most appropriate composition. HEMA is the most widely used acrylic monomer in nail coatings due to its outstanding characteristics: high reactivity (temperature reached at polymerization Tmax = 95 °C), good adhesion (1.5 MPa on glass and aluminum), high solubility in acetone (ms = 22 %). The greatest potential to substitute HEMA has monomer HPMA, due to its good abrasion resistance (G = 66 GU after abrasion), high reactivity (Tmax = 88 °C), and adhesion (1.5 MPa on glass and on aluminum). The polymerization process of a composition containing MEP was the fastest and reached the highest maximum temperature during polymerization process (Tmax = 115 °C) and great adhesion (2.5 MPa). The best surface abrasion resistance (G = 76 GU after abrasion) was reached for coatings containing TMPTMA.

Amorphous Macromers as Potential Organic Matrix in Dental Composites

Objectives: Assess the thermal and hydrolytic stability of patented macromer- based dental polymer matrices and composites Methods: Polymer matrices and composites based on a patented material (IP:343192) containing hybrid amorphous macromers co-polymerized with one of the 4 different dimethacrylates was prepared and the thermal and photo-thermal behavior were assessed. Diffusivity resistance and cross-link density of polymers were assessed. Sorption (𝑆(𝑡), 𝑀𝑔%(𝑡) 𝖠 𝑆%(𝑡)and solubility (𝑆𝐿(𝑡) 𝖠 𝑆𝐿%(𝑡) of composites in chloroform (CHCl3), tetrahydrofuran (THF), carbon tetrachloride (CCL) and acetone (Ace) for varying durations (1h, 24h 1mo), and deionized water for 120h were determined. Results: Dual Tg were noticed for both the matrices and composites; matrices containing BisGMA (G) and UDMA (U) as the dimethacrylate co-polymer showed significantly lower𝑆𝐿(𝑡). Matrix containing TEGDMA (T) as the dimethacrylate co-polymer showed the least 𝑆(𝑡). Matrix containing BisEMA (E) had the highest cross-link density. photo-DSC of composites showed a Degree of Conversion of 97% at lower enthalpies (15-28J/g). None of the composites showed water solubility. All materials showed solubility in acetone with U being the least. Sorption and solubility in other organic solvents was lower and occurred only at longer immersion time. Conclusions: Amorphous hybrid macromer-based polymer matrices and composites show promising thermal and hydrolytic behavior.

Molecular Dynamics Simulation for Separation Performance of PDMS/Fluorosilane Membrane with Different Mass Ratios in Acetone–Water Mixture

AbstractPolydimethylsiloxane (PDMS) membrane in suitable‐fluorinated level have excellent pervaporation performance as well as antibiological contamination performance. The pervaporation membranes with different PDMS/fluorosilane mass ratios, the adsorption and dissolution behaviors of acetone molecules on the membrane surface, as well as the diffusion and permeation behaviors in the membranes are studied by all‐atom molecular dynamics simulation (AAMDS). The results show that when the mass ratio of PDMS/fluorosilane is 100/20, the surface solubility of acetone is 11.711 (J cm−3)0.5, and the interfacial interaction is −16897.0415 kcal mol−1, both of which are the highest. The results of wide‐angle X‐ray diffraction (WAXD) showed that there are amorphous regions in the membranes suitable for acetone penetration. The maximum chain spacing of the PDMS/fluorosilane(100/20)_membranes is 10.8482 Å, and the free volume fraction (FFV) is 3.03%, both of which are the largest. The change rate of long‐term mean square displacement (MSD) in PDMS/fluorosilane(100/20)_Membrane with time is 0.45269. The Young's modulus E, shear modulus G, volume modulus K, and Poisson's ratio ν of PDMS/fluorosilane(100/20)_Membrane are 0.3249, 0.4061, 0.0492 GPa and ‐0.5999, respectively. The elasticity of the membrane enhances the diffusion behavior of acetone molecules, and the self‐diffusion coefficient of acetone in the membrane is 0.07545 Å2 ps−1.

Solubility and diffusivity of six volatile compounds in ionic liquids [BMIM][Tf2N], [BMPy][Tf2N], [BMIM][TfO] and [BMPy][TfO

Diffusivity and solubility of water, methanol, ethanol, 1-butanol, acetone and p-xylene in four ionic liquids (ILs) were determined microgravimetrically by studying the absorption of the vapors (without air) in the ILs at 40 °C. The studied ILs comprised of all four possible combinations of two cations [1-butyl-3-methylimidazolium, BMIM, and 1-butyl-1-mehtylpyrrolidinium, BMPy] and two anions [bis(trifluoromethylsulfonyl)imide, Tf2N, and trifluoromethanesulfonate, TfO]; data for 24 systems are reported. Higher solubility of the vapors of protic compounds (water, methanol, ethanol and 1-butanol) was observed for the ILs containing the TfO anion while higher solubility of aprotic compounds (acetone and p-xylene) was observed for ILs containing the Tf2N anion. While ILs containing BMPy cation showed discernibly higher solubilities than those containing BMIM in for 1-butanol in TfO based ILs and p-xylene in Tf2N based ILs, limited solubility changes due to the cation exchange were observed for the remaining systems. The equilibrium dissolution was parameterized using the Margules and Guggenheim, Anderson, de Boer (GAB) models. For all compounds except water, mutual diffusivity followed the relations BMIM > BMPy and Tf2N > TfO, while for water it followed BMIM > BMPy and TfO > Tf2N. Diffusion was anomalously fast with respect to the Einstein-Stokes-Sutherland equation in all studied systems presumably due to the “cage” and “jump” mechanism. Despite the observed non-ideality of the liquid phase, mutual diffusivities were practically constant over the tested ranges of vapor activity (and concentration) for most systems while thermodynamic (self) diffusivities varied with the experimental conditions. Overall, structure-property relationships were assessed for four combinations of practically relevant constituting ions and six volatile solutes at 40 °C.

Hydrophobic deep eutectic solvents as green absorbents for hydrophilic VOC elimination

As a common hydrophilic volatile organic compound (VOC), acetone is known to harm human health and the atmospheric environment. Absorption is a typical technique applied to capture hydrophilic VOCs; however, the difficulty of separating and recovering absorbed hydrophilic VOCs (e.g., acetone) from aqueous absorbents has become one of the major challenges in practical applications. Hydrophobic deep eutectic solvents (DESs) have therefore been developed as novel green absorbents for capturing hydrophilic VOCs in the present work. The compiled results show that efficient hydrophilic VOC elimination can be accomplished by the proposed hydrophobic DESs through high absorption capacity and thermodynamically favorable gas-to-liquid mass transfer. Among the explored DESs, the hydrophobic DES containing thymol [Thy] and decanoic acid [DecA] with a molar ratio of 1:1 has achieved the highest absorption capacity of acetone, i.e., 6.57 mg acetone per g DES at 20 °C and 1480 ppm acetone. The oxygen of acetone interacts favorably with the hydrogen atom of [Thy] upon absorption, rendering hydrogen bonding interaction surpassing polarity as the key factor in attaining superior solubility of acetone in DESs. Moreover, the absorbed acetone can be easily removed from Thy-based DESs, realizing an effective hydrophilic VOC elimination process with economic and ecological benefits.

Utilization of cellulose in tobacco (Nicotiana tobacum) stalks for nitrocellulose production

This research explains the conversion of waste tobacco stalks into nitrocellulose to try to recover as much chemical potential contained in the biomass material as possible. Simple pioneering experiments were conducted using pulping tobacco stalks with a moisture content of 10.17 wt% and the soda pulping method being applied to produce cellulose pulp. The cellulose pulp was bleached using calcium hypochlorite to produce a dry white lignin-free pulp, which was subjected to nitration. The mixture used was 67% nitric acid and 98% sulphuric acid, and the acid ratio was varied between 3:7 and 7:3 v/v. Nitration time was varied between 5 and 25 min. This process produced nitrocellulose with all the various conditions. The nitrocellulose obtained with nitrogen content between 11 – 11.5% v/v was characterized using its solubility in acetone. An optimum nitrating mixture of 1:1 v/v with a nitration time of 5 min was used to produce nitrocellulose from tobacco stalks using soda pulping. The results show a great potential for tobacco farming countries to reduce their nitrocellulose import bill using this process.

Design Development and Characterization of Mannosylated Carbon Nanotubes

The proposed study was aimed atdeveloping and exploring the efficiency of novel mannosylated MWCNTs. For selectivedrug delivery to alveolar macrophages,Paclitaxel was selected for incorporation intomannosylated MWCNTs based on itsanticancer activity. Hopefully, this deliverysystem could be safely administered throughi.v. route. We expect that this approach willimprove management of drug therapy in cancerpatients by delivering the drug at controlled rate for prolonged period of time at a desiredsite. The drug was found to be white to offwhite, crystalline powder that was similar in physical appearance as mentioned in I.P. 1996. Melting point of Paclitaxel was near to reported value. Solubility of the drug in different solvents at ambient temperature depicted its solubility in methanol, ethanol, acetone, dimethylsulphoxide and chloroform, while insoluble in distilled and PBS (pH 7.4). Drug entrapment efficiency of Paclitaxel loaded mannosylated MWCNTs was found to be increased.

Revealing dissolution behavior of o-methoxybenzoic acid in twelve pure solvents using thermodynamic analysis and molecular simulation

The solubility of o-methoxybenzoic acid (OMBA) in twelve pure solvents range from 283.15 to 323.15 K was investigated by the experiments and molecular simulations. The result of gravimetric method showed that OMBA has the highest solubility in acetone and the lowest solubility in water. Molecular simulations of MPI, MEPs, HS and SFE were employed to understand the dissolution behavior. In particular, MPI had proved to be an uncommon but effective parameter, which can provide a better explanation based on the polarity of “like dissolves like”. Moreover, the intermolecular interactions derived from HS analysis indicated that the H-H contacts as well as the C=O∙∙∙H-O hydrogen bonding interactions were dominant in the crystal packing of OMBA. Six thermodynamic models were further selected to correlate experimental solubility results successfully as the ARD% values of the six models were less than 7%. The mixing thermodynamic properties obtained from the correlated results of the NRTL model, indicating that the dissolution process is spontaneous and entropy-driven. The experimental data can be used as a useful basis for the industrial production of intermediate product OMBA.

Mild nitric acid treatments to improve multi-walled carbon nanotubes dispersity and solubility in dielectrophoresis mediums

The major limitation of carbon nanotubes (CNTs) is their poor solubility in the common solvents. Solving the solubility issue of CNTs is comprehended either by functionalizing the CNTs or using a dispersity agent. Agents such as ionic surfactant dramatically alter the suspension conductivity causing undesirable thermal flow in dielectrophoresis (DEP) mediums. In this study, the lack of CNTs solubility in common solvents was resolved by functionalizing multi-wall carbon nanotubes (MWCNTs) using a mild regulated procedure. The mild treatment was used to maintain the electrical conductivity of MWCNTs, since its essential for their dielectrophoretic response. Fourier-transform infrared (FTIR) spectroscopy, high-resolution transmission electron microscopy (HRTEM), and Raman spectroscopy were used to investigate the treatment quality. The ability of different solvents to dissolve MWCNT agglomerates after treatment was analyzed using ultraviolet-visible (UV-Vis) spectroscopy and dynamic light scattering (DLS) analysis. The characterization results indicate that the treated MWCNTs by the presented procedure contain hydroxylic and carboxylic functional groups and showed strong solubility in water, dimethylformamide (DMF) and acetone. This study provides a better solution to improve the processability of MWCNTs in common solvents without degrading their electrical conductivity.

Radiolysis-Induced Crystallization of Sodium Chloride in Acetone by Electron Beam Irradiation.

In situ liquid cell transmission electron microscopy (LC-TEM) is an innovative method for studying the processes involved in the formation of crystals in liquids. However, it is difficult to capture early stages of crystallization because of the small field of view and the unfavorable changes in sample composition resulting from electron-beam radiolysis. Nevertheless, if the radiolysis required to induce the crystallization of a sample could be controlled in LC-TEM, this would be advantageous for observing the crystallization process. Here, we examined this possibility by using a mixture of sodium chlorate (NaClO3) and acetone in the LC-TEM. The electron beam induced the formation of dendritic crystals in a saturated acetone solution of NaClO3; moreover, these crystals consisted of sodium chloride (NaCl), rather than NaClO3, suggesting that chloride ions (Cl−), which were not present in the initial solution, were generated by radiolysis of chlorate ions ${\rm \lpar ClO}_3^- \rpar$. As a result, the solution then supersaturated with NaCl because its solubility in acetone is much lower than that of NaClO3. The combination of radiolysis and a solvent in which a solute is much less soluble is potentially useful for establishing crystallization conditions for materials that are difficult to crystallize directly in LC-TEM experiments.

Determination and correlation of solubility and solution thermodynamics of 1, 2-diphenylethane in different pure solvents

The correlation of solubility and solution thermodynamics of 1,2- diphenylethane in different pure solvents has been studied. The mole fraction solubilities of 1, 2-diphenylethane in acetone, chloroform, dichloromethane, and ethanol increase with temperature. The mole fraction solubility in acetone, chloroform and dichloromethaneare much higher than that in ethanol and the mole fraction solubilities in chloroform and dichloromethane are higher than that in acetone. The solubility data were well correlated by the modified Apelblat,the semi-empirical Buchowski-Ksiazczak λh equation, and the ideal solution equation.The enthalpy, entropy and apparent free Gibbs energy of solution in different solvents were calculated. The dissolving process of 1,2-diphenylethane was endothermic, entropy-driving and not spontaneous.

Vapor-liquid equilibrium, liquid density and excess enthalpy of the carbon dioxide+acetone mixture: Experimental measurements and correlations

ABSTRACT New vapor-liquid equilibrium data of the CO2+acetone mixture were determined from vapor pressure measurements using a static and synthetic method from (283.15 to 383.15) K and a composition range from (4 to 85) % in CO2 mole fraction. The fugacity coefficients approach with the Soave-Redlich-Kwong equation of state was used to calculate the composition of the phases and the binary interaction parameter. The average relative deviation between the experimental and calculated pressure values was 0.14 % and the maximum deviation was 5.0 %. Carbon dioxide shows total miscibility and good solubility in acetone in the conditions studied. The liquid density of the mixture was measured with a vibrating-tube densimeter from (283.15 to 353.15) K, at sufficient pressure to guarantee the liquid state, and a composition range from (6 to 82) % in CO2 mole fraction. The liquid density values calculated by the equation of state with the Peneloux correction were compared with the experimental values and agreement was good with a maximum deviation of 7 % and an average deviation of 0.7 %. The excess molar enthalpies were measured by a flow-calorimetric technique at (283.30 and 298.30) K and pressures from (9.00 to 14.00) MPa. Finally, the experimental data on vapor pressure, density, and excess molar enthalpy were fitted using empirical equations, and the first two were compared with data reported in the literature. Average deviations were between (0.07 and 30) % in the vapor-liquid equilibrium, and between (0.51 and 8.8) % in the density.

Study on the preparation of geranyl acetone and \u03b2-cyclodextrin inclusion complex and its application in cigarette flavoring

β-Cyclodextrin (β-CD) inclusion complex containing geranyl acetone as a guest was prepared by saturated water solution method. Furthermore, the structure and properties of the inclusion complex were studied. The formation of the inclusion complex was demonstrated by. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (X-RD), thermogravimetric analysis (TG) and differential scanning calorimetry (DSC). The thermodynamic analysis of the inclusion complex showed that the inclusion reaction is an endothermic spontaneous reaction. The average of △H, △S and △G is 11.66 kJ mol−1, 0.082 kJ mol−1 and − 14.49 kJ mol−1, respectively. Moreover, the kinetic analysis of thermal decomposition of the inclusion compound showed that the thermal decomposition reaction is a first-order reaction (the inclusion ratio is 1:1), the average activation energy of the reaction is 180.90 kJ mol−1, and the binding force in the inclusion compound is mainly Van der Waals force. The flavor test of cigarettes showed that the inclusion compound improved the stability of geranyl acetone and the sensory quality of cigarettes. This study improves the solubility and thermal stability of geranyl acetone, and provides theoretical support and technical guidance for expanding the application of geranyl acetone.

New heterocyclic conjugated azomethines containing triphenylamine units with optical and electrochemical responses towards the acid environment

A series of heteroaromatic azomethines containing phenyl, pyridine, thiophene or furan ring and ortho-catenated triphenylamine (TPA) core was synthesized and used to investigate the effect of the structural variation on opto-electronic and acid-sensing properties. The twisted structure induced by the TPA core enabled good solubility in organic solvents, including chloroform, acetone or ethyl acetate. Meanwhile, they preserved good thermal stability and showed high glass transition temperatures. The modulation of optical and electronic properties of azomethines was most likely due to two effects: the degree of coplanarity induced by the heterocyclic moiety and the electronic effect of the π-rich heterocycle that is electron-withdrawing (pyridine) or electron-acceptor (thiophene and furan). A detailed study was accomplished with respect to the acid recognition capability promoted by the electronic and basicity character of the azomethine center. The spectroscopic and electrochemical responses to acid environment were followed by cyclic voltammetry, FTIR, fluorescence and UV–vis spectroscopy. Different spectral changes occurred when doping was performed with hydrochloric and trifluoroacetic acids. The sensing properties toward the environmental pH modification were mostly accompanied by fluorescence quenching and driven by different recognition principles with respect to the acid dopant type.

Green Synthesis and Fractionation of Cellulose Acetate by Controlling the Reactivity of Polysaccharides in Sugarcane Bagasse

A green synthetic protocol was developed to prepare cellulose acetate (CA) directly from sugarcane bagasse without using any pretreatments or corrosive reagents, such as strong acids, bases, or halogenated chemicals. The key in this method is to control the reactivities of cellulose and xylan-based hemicellulose in bagasse under mild conditions, making their solubilities in acetone different. Homogeneous transesterification was performed for bagasse at 50 °C using isopropenyl acetate as an acetyl donor and 1-ethyl-3-methylimidazolium acetate as a solvent and catalyst. By controlling the reaction temperature, the degree of substitution for cellulose was adjusted to 2.5–2.8 to maintain solubility in acetone, while the acetylation of hemicellulose was suppressed to prevent its dissolution in acetone. In the subsequent fractionation process, the hemicellulose-rich component was first precipitated in acetone and removed by filtration. The filtrate was subsequently separated into lignin- and cellulose-rich fractions by solid–liquid separation using methanol. Then, CA as the target compound was collected as the acetone-soluble and methanol-insoluble fraction, with a sufficiently high purity (∼90%), according to FT-IR and 1H NMR analyses.

Concentrated sulfuric acid hydrolysis of softwood with t-butyl alcohol

To date, concentrated sulfuric acid hydrolysis is the most effective process to recover the maximum yield of monomeric sugars from woody biomass because concentrated sulfuric acid can completely swell and hydrolyze cellulose. During this process, sulfuric acid lignin is quantitatively produced as a by-product, which is difficult to use because of self-condensation between the lignin molecules under acidic conditions. In this study, to achieve a high yield of both sugars and lignin, we aimed to valorize the lignin with a unique additive, t-butyl alcohol, in the concentrated sulfuric acid hydrolysis of softwood. When t-butyl alcohol was added, sugar yields were unchanged and were nearly equal to the amount of compositional sugars. Thermoplastic lignin with good solubility in acetone was successfully recovered in a yield higher than 40%. The economic efficiency of the concentrated acid hydrolysis was significantly improved by upgrading the lignin. Thus, this unique process could be a new candidate in the realization of sugar platform biorefineries.

Composition, production, physicochemical properties and applications of lecithin obtained from rice (Oryza sativa L.) - A review

Rice bran oil is a rich source of lecithin and has many beneficial effects on human health. Apart from phospholipids (1-2%), different nutrients like ?-oryzanol, ferulic acid, phytosterols and vitamin B are also present in rice bran oil. These impart emulsifying property, anti-spattering property etc. and therefore, serve as potential nutritional food and nutraceutical. This review describes the composition, production, physicochemical properties, separation of individual phospholipids from rice bran lecithin and its applications in food industry. It is difficult to handle as compared to soyabean lecithin due to the problem of wax entrapment during the isolation of gums. It is characterised on the basis of physicochemical properties viz. solubility in acetone and hexane, colour, peroxide value, moisture content and acid value. Rice bran lecithin can serve as an excellent substitute to the available lecithins as it is non-GM and its nutritional and fatty acid composition imparts many properties which help it to find applications in the food industry. Future work must focus on proper processing of rice bran oil so that the lecithin obtained during processing is of high quality so that it can pave a way in the food sector.

Solubility measurements and thermodynamic modeling of pyrazinamide in five different solvent-antisolvent mixtures

Pyrazinamide, an important first line drug for the treatment of Mycobacterium tuberculosis, has different polymorphic forms among which the plate like metastable δ-polymorphic form is desirable for ease of downstream processing. Pyrazinamide has reasonably good solubility in acetone, 1,4-dioxane and methanol; but very low solubility in toluene and cyclohexane. Also, the δ-polymorphic form of pyrazinamide can be obtained by antisolvent crystallization using any of these five solvent-antisolvent pairs. In this work, the solubility of pyrazinamide in acetone-toluene, acetone-cyclohexane, 1,4-dioxane-toluene, 1,4-dioxane-cyclohexane and methanol-toluene mixtures is measured by gravimetric method within the temperature range of 283.15 K to 333.15 K over antisolvent composition upto 70 wt%. The solubility of pyrazinamide increases with increase in temperature for all systems at constant antisolvent (toluene and cyclohexane) composition and decreases with increase in antisolvent composition for the given temperature range for all systems except methanol-toluene system. The solubility of pyrazinamide in methanol-toluene system increases with increase in toluene composition upto 40 wt% and then decreases with increase in toluene composition. Three thermodynamic models namely UNIQUAC, NRTL, and Wilson are used to correlate the solubility of pyrazinamide in above solvent-antisolvent mixtures. A nonlinear optimization technique was used to determine the adjustable parameters of various models. The accuracy of the model correlation has been evaluated on the basis of relative average deviation, root mean square deviation and Akaike Information Criterion. All the models represented the experimental solubility data with good accuracy, the maximum root mean square deviation being 5.21. The dissolution enthalpy and dissolution entropy of pyrazinamide in above solution mixtures were calculated from the slope and intercept of van't Hoff equation which shows that solvation of pyrazinamide in these mixed solvents is endothermic and enthalpy-driven.