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Dichlone (2,3-dichloronaphthalene-1,4-dione) is an important antimicrobial agent for agriculture, which effectiveness could be improved by modifying its structure, while the recovery of high-purity synthesized derivatives from a reaction mixture could be accomplished by extracting them with supercritical carbon dioxide. Two new amine derivatives, 2-chloro-3-((4-chlorobenzyl)amino)naphthalene-1,4-dione (dCl-2B-Cl) and 2-chloro-3-((4-chlorophenethyl)amino)naphthalene-1,4-dione (dCl‐3P‐Cl), were synthesized from dichlone, and their solubility in supercritical carbon dioxide was measured afterwards at (313, 323 and 333) K and a pressure range from (8−33) MPa. Experimental solubilities spanned from (10.3·10-6 to 22.1·10-6) mol·mol-1 for dCl-2B-Cl, and from (32.7·10-6 to 131·10-6) mol·mol-1 for dCl‐3P‐Cl. The solubility data of the dichlone family (dichlone, dCl-2B-Cl, dCl‐3P‐Cl, 2‐(benzylamino)‐3‐chloronaphthalene‐1,4‐dione (dCl-2B) and 2-chloro-3-(phenethylamino)naphthalene-1,4-dione (dCl‐3P)) was compared using three models, i.e., the Chrastil equation, the Molecular Connectivity Indices model, and the Statistical Associating Fluid Theory of Variable Range and Mie Potential equation of state, to identify the quantitative structure-property relationship between them. Solubility had an inverse relation with solute size and polarity, but there were some exceptions that could be explained by performing a stereochemical analysis, which showed that steric effects involved in the folding of dCl‐3P and dCl‐3P‐Cl provided them a better geometry for solvation than dCl-2B and dCl-2B-Cl, respectively, making them more soluble. This demonstrates that the solute geometry is an important factor in the solvation process, and it must be represented accurately to develop better predictive models. [Display omitted] • Two new dichlone derivatives were synthetized, purified, and characterized, with 98% purity. • Solubility of dichlone derivatives in SC-CO 2 was measured at 313 K < T < 333 K, 8 MPa < P < 33 MPa. • Dichlone and its derivatives were compared using three solubility models to identify the structure-property relationship between them. • An apparent trade-off between the accuracy of the models and their physicochemical significance was observed, which urges the development of better solubility models. • Solubility had an inverse relation with the solute size and polarity, but there were some exceptions that motivated a stereochemical analysis. • The solute geometry could be an important factor in the solvation process to justify the solubility reversal trend and prove useful to enhance solubility prediction. [ABSTRACT FROM AUTHOR]

Two solid derivatives of dichlone (2,3-dichloronaphthalene-1,4-dione), 2-(benzylamino)-3-chloronaphthalene-1,4-dione and 2-chloro-3-(phenethylamino)naphthalene-1,4-dione were synthetized by replacing the chlorine atom with the amine substituent by means of a substitution reaction, with a purity grade of 98% mol mol −1 . The solubility expressed as molar fraction of each solid derivative in the supercritical carbon dioxide rich-phase was measured at (313, 323 and 333) K and pressures ranged from (8.59 to 32.51) MPa, using a recirculation method with direct determination of the solubility in a high performance liquid chromatography. Results indicated that the measured solubility ranges were between (23·10 −6 and 114·10 −6 ) mol mol −1 for solid 2-(benzylamino)-3-chloronaphthalene-1,4-dione. For the second solid derivative, 2-chloro-3-(phenethylamino)naphthalene-1,4-dione measured solubilities were between (57·10 −6 and 161·10 −6 ) mol mol −1 . Experimental measured solubility values were analyzed by using a procedure that included the estimation of the combined expanded uncertainty for each solubility data point and the evaluation of the thermodynamic consistency utilizing a test based on the Gibbs-Duhem equation. In addition, the self-consistency was verifying by correlating the experimental solubility data with a semi-empirical model as a function of temperature, pressure and pure carbon dioxide density. [ABSTRACT FROM AUTHOR]

Synthesis of two solid derivatives of vitamin K 3 (2-methylnaphthalene-1,4-dione or menadione), 2-(benzylamino)-3-methylnaphthalene-1,4-dione and 3-(phenethylamino)-2-methylnaphthalene-1,4-dione was completed using a 1,4 Michael addition reaction at 323 K in an inert atmosphere, with reaction yields of 62% mol·mol −1 and 71% mol·mol −1 , respectively, and a purity grade of 98% mol·mol −1 for each component. Isothermal solubility (mole fraction) of each solid derivative in supercritical carbon dioxide was performed using an analytic-recirculation methodology, with direct determination of the molar composition of the carbon dioxide-rich phase by using high performance liquid chromatography, at temperatures of (313, 323 and 333) K and pressures from (8–28) MPa. Results indicated that the range of measured solubilities were from (59 × 10 −6 to 368 × 10 −6 ) mol·mol −1 for solid 2-(benzylamino)-3-methylnaphthalene-1,4-dione and from (40 × 10 −6 to 205 × 10 −6 ) mol·mol −1 for solid 3-(phenethylamino)-2-methylnaphthalene-1,4-dione. The experimental solubility was validated using three approaches, estimating the combined expanded uncertainty of measurement for each solubility data point, evaluating the thermodynamic consistency of the data utilizing a test based on the Gibbs–Duhem equation, and verifying the self-consistency by correlating the experimental solubility values with a semi-empirical model as a function of temperature, pressure and pure carbon dioxide density. [ABSTRACT FROM AUTHOR]

• Two menadione derivatives were synthetized, purified and characterized. • Solubility of dichlone derivatives in SC-CO 2 was measured at T < 333 K, P < 33 MPa. • Solubility data was correlated in terms of temperature and CO 2 density with deviations <8 %. • Solubility of dichlone derivatives showed an unexpected increase with the molecular weight. • The molecular conformation could justify the solubility reversal trend. Two solid derivatives of vitamin K 3 or menadione, 2-((4-chlorobenzyl)amino)-3-methylnaphthalene-1,4-dione and 2-((4-chlorophenethyl)amino)-3-methylnaphthalene-1,4-dione, were synthesized and chemically characterized with a purity of 98 % mol∙mol−1. The solubility (molar fraction) of each derivative in high-pressure carbon dioxide was measured using an analytic-recirculation methodology at (313, 323 and 333) K, and pressures from (8.72–33.67) MPa. The solubility values were from (22·10-6 to 99·10-6) mol·mol−1, and from (48·10-6 to 223·10-6) for 2-((4-chlorobenzyl)amino)-3-methylnaphthalene-1,4-dione and 2-((4-chlorophenethyl)amino)-3-methylnaphthalene-1,4-dione respectively. Questionable experimental data points were detected calculating the combined expanded uncertainty, applying the thermodynamic consistency and the self-consistency tests, as well as analyzing the chemical structure of the solute after it had been measured. The solvent power of the high-pressure carbon dioxide over the synthesized menadione solid derivatives was studied based on the parameters of the equation of Chrastil adjusted to the experimental data, in order to have evidence of the relationship between solute molecular structure and solubility. [ABSTRACT FROM AUTHOR]

Dichlone, also known as 2,3-dichloronaphthalene-1,4-dione, is a solid organic substance employed in the field of agriculture for its fungicidal properties and as a retardant for vegetable decomposition. The bioactive properties of dichlone can be enhanced by modifying its structure, specifically through the synthesis of new derivatives achieved by replacing the functional groups within its molecular structure. Two new solid dichlone derivatives were synthesized in this work, namely 2-chloro-3-((4-fluorobenzyl)amino)naphthalene-1,4-dione (dCl-2B-F) and 2-chloro-3-((4-fluorophenethyl)amino)naphthalene-1,4-dione (dCl-3 P-F) and measured their solubility in supercritical carbon dioxide at (313, 323, and 333) K and pressures between (9. to 32) MPa. The results indicated that solubility ranged between 30.5 and 47.9 µmol of solute/mol of CO 2 for dCl-2B-F, and from 2.2 to 243.5 µmol of solute/mol of CO 2 for dCl-3 P-F. The solubility data of dichlone and its synthesized derivatives (dCl-2B-F, dCl-3 P-F, 2-chloro-3-((4-chlorobenzyl)amino)naphthalene-1,4-dione (dCl-2B-Cl), 2-chloro-3-((4-chlorophenethyl)amino)naphthalene-1,4-dione (dCl-3 P-Cl), 2-(benzylamino)-3-chloronaphthalene-1,4-dione (dCl-2B) and 2-chloro-3-(phenethylamino)naphthalene-1,4-dione (dCl-3 P)) was compared using the density-based correlation of Chrastil and the Statistical Associating Fluid Theory of Variable Range Mie-potential (SAFT-VR Mie) equation of state (EoS), to better comprehend the effects of the structural differences on the solubility. As a result, for the Chrastil model, a root mean square deviation (rmsd) of 3% was obtained for dCl-2B-F and 16% for dCl-3 P-F, whereas for the SAFT-VR Mie equation, it averaged 24% for dCl-2B-F and 28% for dCl-3 P-F. It was found that the solubility of the homologous compounds, differing only in one methylene group, increased with solute size (-2B derivatives were less soluble in CO 2 than the −3 P ones), contrary to the expected trend, which could be attributed to the increased probability of ring-to-ring interactions as the chain length connecting the rings decreases. This demonstrates that geometric factors, along with the pressure and temperature, affect the behavior of the solubility and these should be accurately represented in the predictive models. [Display omitted] ● Two novel dichlone derivatives were synthetized, purified, and characterized. ● Chemical structures of the solutes were determined by NMR and HRMS analyzes. ● Solubility of solutes in CO 2 was measured at 313 K, 323 K and 333 K, and < 32 MPa. ● Two solubility models were used, Chrastil equation and SAFT-VR-Mie EoS. ● Molecular weight and geometry affected the solubility of dichlone derivatives. [ABSTRACT FROM AUTHOR]

This work reports the solubility of menadione (2-methyl-1,4-naphthoquinone) and dichlone (2,3-dichloro-1,4-naphthoquinone) in SuperCritical (SC) carbon dioxide (CO 2 ) at 313, 323, and 333 K and (7.1–33) MPa. A Gibbs-Duhem test was applied to assess the thermodynamic consistency of experimental data using the Peng-Robinson equation of state with Wong-Sandler mixing rule to represent the solubility, and the non-random two-liquid model to compute Gibbs' excess free energy. In addition, the solubility of menadione and dichlone in SC-CO 2 at 313 K and 9.5 MPa, a solubility correction by a change in the density of SC-CO 2 as compared to this reference condition (580 kg/m 3 ), and a solubility correction by a change in absolute temperature compared to 313 K were estimated using Chrastil's equation. The solubility of menadione at the reference conditions was 8.3 times higher than that of dichlone (3095 versus 375 mg kg −1 solute/CO 2 ). However, both CO 2 density and system absolute temperature had anomalously smaller effects on the solubility of menadione than dichlone, so that menadione was only 4.2 time more soluble in SC-CO 2 than dichlone at the extreme conditions of 333 K and 33 MPa (3460 versus 831 mg kg −1 solute/CO 2 ) for which ρ = 851.1 kg/m 3 . The anomalous behavior of the solubility of menadione in SC-CO 2 was imputed to experimental difficulties (solute precipitation resulting in tube blocking, saturation of HPLC detector signal) associated with high solubility values (≥0.5 × 10 −3 M fraction) that may have been also responsible for thermodynamically inconsistent results reported by others in literature. We compared the solubilities in SC-CO 2 of menadione and dichlone with those for several solutes sharing the same molecule core (1,4-naphthoquinone) and concluded they are negatively impacted by polar and non-polar substituents, but that these negative steric and polarity effects could be partially compensated by a non-polar olefin substituent, or ameliorated by distancing substitutions from the carbonyl groups. [ABSTRACT FROM AUTHOR]