Thermodynamics of molecular interactions in binary mixtures containing nitromethane: Molar excess volumes and molar excess enthalpies

65-69<span style="font-size:12.0pt;font-family: " times="" new="" roman";mso-fareast-font-family:"times="" roman";mso-ansi-language:="" en-in;mso-fareast-language:en-in;mso-bidi-language:ar-sa"="" lang="EN-IN">Molar excess volumes, VE and molar excess enthalpies, HE, for nitromethane(i) isopropanol or +n-butanol(j) binary mixtures have been measured by dilatometer and microflow calorimeter as a function of composition at 308.15K. The VE data have been analysed in terms of graph-theoretical approach to extract information about the state of isopropanol or n-butanol in pure and mixture states. It has been observed that isopropanol and <i style="mso-bidi-font-style: normal">n-butanol exist as dimer in the pure state and the (i+j) mixtures are characterised by interactions between oxygen and nitrogen atoms of nitromethane (i) with hydrogen and oxygen atoms of alcoholic group of alcohols to form 1:1 molecular complex. The energetics of the mixtures have also been discussed.</span

Topological investigations of molecular interactions in binary mixtures containing methylene bromide

586-591Molar excess volumes and molar excess enthalpies of methylene bromide(i)+ cyclohexane (j) and methylene bromide(i) + m-nitrotoluene(j) mixtures have been determined diiatometrically andcalorimetrically as a function of composition at 308.15 K. The analysis of VE data by graph-theoretical approach reveals that methylene bromide + m-nitrotoluene mixture is characterised by interactions between the delocalised p - electron cloud over nitrogen and oxygen atoms of nitro group in m-nitrotoluene and vacant 3d orbitals of bromine atom in methylene bromide. IR studies lend additional support to the nature and extent of interactions for the proposed structure in the mixture. The observed data have also been analysed in terms of Sanchez and Lacombe's theory [J phys Chem, 80(1976)2352; 80(1976)2568]

Ultrasonic speeds and isentropic compressibilities of some water + non-electrolyte mixtures

59-62Ultrasonic speeds for water (i) + pyridine (j) or &alpha;-, &beta;- or &lambda;-picoline (j) binary mixtures have been measured as a function of composition at 298.15 and 308. 15K. The observed data have been utilized to evaluate the values of isentropic (Ks) and excess isentropic compressibilities (KsE)

Solvent Dependence on Cooperative Vibrational Strong Coupling and Cavity Catalysis

Strong light-matter coupling offers a unique way to control chemical reactions at the molecular level. Here, we try to compare the solvent effect on a solvolysis process under cooperative vibrational strong coupling (VSC). Two solvents, ethyl acetate and cyclopentanone are chosen to study cavity catalysis by coupling the C=O stretching band of the reactant and the solvent molecules to a Fabry-Perot cavity mode. Interestingly, both the solvent system catalyze the chemical reaction under cooperative VSC conditions. However, the resonance effect on catalysis is observed at different temperatures for the two solvent systems, which is further confirmed by thermodynamic studies. Cavity detuning and other control experiments suggest that cooperative VSC of the solvent plays a crucial role in modifying the transition state energy of the reaction. These findings, along with other observations, cement the concept of polaritonic chemistry

Topological investigations of molecular interactions in water + 1,4 -dioxane mixture

271-274<span style="font-size:14.0pt;font-family:Fd357953-Identity-H;mso-bidi-font-family: Fd357953-Identity-H;color:#161616">Molar excess volumes, V<span style="font-size:14.0pt;font-family:Fd694979-Identity-H;mso-bidi-font-family: Fd694979-Identity-H;color:#161616">E<span style="font-size:14.0pt; font-family:Fd694979-Identity-H;mso-bidi-font-family:Fd694979-Identity-H; color:#161616">-, <span style="font-size:14.0pt;font-family:Fd357953-Identity-H; mso-bidi-font-family:Fd357953-Identity-H;color:#161616">and molar excess enthalpies, <span style="font-size:14.0pt;font-family:Fd694983-Identity-H;mso-bidi-font-family: Fd694983-Identity-H;color:#161616">H<span style="font-size: 14.0pt;font-family:Fd694979-Identity-H;mso-bidi-font-family:Fd694979-Identity-H; color:#161616">E<span style="font-size:14.0pt;font-family:Fd694983-Identity-H; mso-bidi-font-family:Fd694983-Identity-H;color:#161616">, <span style="font-size:14.0pt;font-family:Fd357953-Identity-H;mso-bidi-font-family: Fd357953-Identity-H;color:#161616">for water (i) <span style="font-size: 14.0pt;font-family:Fd694983-Identity-H;mso-bidi-font-family:Fd694983-Identity-H; color:#161616">+ 1,4<span style="font-size:14.0pt;font-family:Fd357953-Identity-H; mso-bidi-font-family:Fd357953-Identity-H;color:#161616"> -dioxane (j) mixture have been determined as a <span style="font-size:14.0pt;font-family:Fd357953-Identity-H;mso-bidi-font-family: Fd357953-Identity-H;color:#141414">function of composition at 303 <span style="font-size:14.0pt;font-family:Fd422163-Identity-H;mso-bidi-font-family: Fd422163-Identity-H;color:#141414">15K. <span style="font-size:14.0pt; font-family:Fd357953-Identity-H;mso-bidi-font-family:Fd357953-Identity-H; color:#141414">The observed data have <span style="font-size:14.0pt;font-family:Fd357953-Identity-H;mso-bidi-font-family: Fd357953-Identity-H;color:#141414">been analysed in terms of the graph-theoretical approach (which <span style="font-size:14.0pt;font-family:Fd357953-Identity-H;mso-bidi-font-family: Fd357953-Identity-H;color:#141414">involves the concept of connectivity parameter of third degree) to extract information about the state of water and 1,4-dioxane in <span style="font-size:14.0pt;font-family:Fd357953-Identity-H;mso-bidi-font-family: Fd357953-Identity-H;color:#141414">pure state and in the mixture. The analysis <span style="font-size:14.0pt;font-family:Fd357953-Identity-H;mso-bidi-font-family: Fd357953-Identity-H;color:#161616">V<span style="font-size:14.0pt; font-family:Fd694979-Identity-H;mso-bidi-font-family:Fd694979-Identity-H; color:#161616">E<span style="font-size:14.0pt;font-family:Fd357953-Identity-H; mso-bidi-font-family:Fd357953-Identity-H;color:#141414"> of <span style="font-size:14.0pt;font-family:Fd694979-Identity-H;mso-bidi-font-family: Fd694979-Identity-H;color:#141414"> <span style="font-size:14.0pt;font-family:Fd357953-Identity-H;mso-bidi-font-family: Fd357953-Identity-H;color:#141414">data  by this <span style="font-size:14.0pt;font-family:Fd357953-Identity-H;mso-bidi-font-family: Fd357953-Identity-H;color:#141414">approach suggests that while 1,4-dioxane and water exist as <span style="font-size:14.0pt;font-family:Fd357953-Identity-H;mso-bidi-font-family: Fd357953-Identity-H;color:#141414">monomer and dimer respectively in the pure state, the mixture <span style="font-size:14.0pt;font-family:Fd687457-Identity-H;mso-bidi-font-family: Fd687457-Identity-H;color:#141414">as <span style="font-size:14.0pt; font-family:Fd357953-Identity-H;mso-bidi-font-family:Fd357953-Identity-H; color:#141414">such contains predontinantly <span style="font-size:14.0pt; font-family:Fd687398-Identity-H;mso-bidi-font-family:Fd687398-Identity-H; color:#141414">1:1<span style="font-size:14.0pt;font-family:Fd694979-Identity-H; mso-bidi-font-family:Fd694979-Identity-H;color:#141414"> <span style="font-size:14.0pt;font-family:Fd357953-Identity-H;mso-bidi-font-family: Fd357953-Identity-H;color:#141414">molecular complex. The <span style="font-size:14.0pt;font-family:Fd357953-Identity-H;mso-bidi-font-family: Fd357953-Identity-H;color:#141414">energetics of the mixture have also been discussed.<span style="font-size:14.0pt;font-family:Fd357953-Identity-H; mso-bidi-font-family:Fd357953-Identity-H;color:black"> </span

Thermodynamics of solutions containing surfactant in mixed solvent

498-506Surface tension and specific conductance data have been measured to determine critical micelle concentration (CMC) values for DTAB and Triton X-100 in mixed solvent (water + α-, + β- and ϒ-picoline solutions) at 298.15, 308.15 and 318. 15K. The observed data have been utilized to evaluate surface parameters, i.e., maximum surface excess concentration (Гmax), minimum area per molecule (Amin) at air-liquid interface, the surface pressure at CMC (πcmc) and standard thermodynamic parameters of micellization, adsorption and transfer of surfactant from aqueous to mixed solvent. The observed specific conductance data have been utilized to evaluate the counter-ion association constant (α) and limiting equivalent conductance (λo), using Onsager's relationship. The observed data have been interpreted in terms of intermolecular interactions operating between various components in solution

Thbrmodynamics of molecular interactions in some water + nonelectrolyte

594-601Molar excess volumes, VE, and molar excess enthalpies, HE, for the various water(i)+pyridine or + α- or + β- or + γ-picoline(j) mixtures have been determined as a function of composition at 298.15 and 308.15 K. The observed data have been analysed by graph theoretical approach which suggest that while water exists as il mixture of dimer and trimer pyridine or α- or β- or γ-picolines exists as a dimer or an equilibrium mixture of monomer and dimer in pure state. Further these mixtures are charaeterised predominantly by the presence of 1:1 molecular complex

Molecular interactions in binary mixtures of non-electrolytes: Molar excess volumes and molar excess enthalpies

727-731Molar excess volumes and molar excess enthalpies for various (i+j) binary m-nitrotoluene (i) + benzene, + toluene + o-, +p- and m-xylene (j) mixtures have been determined as a function of composition at 308.15 K. The data have been analysed in terms of graph-theoretical approach which suggests that these mixtures are characterized by interactions between the π-electron cloud of aromatic hydrocarbons and the delocalized π -electron cloud over the nitrogen and the oxygen atoms of the nitro group of m-nitrotoluene

Physico-chemical studies of some surfactants in water and in water + pyridine mixture

337-341Surface tension and specific conductance values have been measured for the aqueous solutions of dodecyltrimethylammonium bromide (DTAB) and Triton X-100 in pyridine at 298.15, 308.15 and 318.15 K. The observed data have been utilized to evaluate surface and thermodynamic properties of micellization, adsorption at liquid-air interface and transfer of surfactant from aqueous to mixed solvent (water + pyridine). The observed conductance data have been utilized to evaluate the counter-ion association constant (α) and limiting equivalent conductance (0). It has been observed that while in DTAB + water + pyridine system the micellization is favoured both by entropy gain as well as energy effect, in Triton X-100 + water + pyridine system it is favoured by large entropy gain only. The observed data have also been interpreted in terms of intermolecular interactions of various components in solution

Cavity Catalysis: Modifying Linear Free-energy Relationship under Cooperative Vibrational Strong Coupling

Recent understanding of light-matter strong coupling brought a new niche in molecular-level control of chemical reactions. Vibrational strong coupling is unique in this category that overcomes the issue associated with coherent chemistry. Here, a vibrational transition is coupled to a standing wave of electromagnetic field, result in strong interaction, generating vibro-polaritonic states. This process reshuffles the entire energy-reaction coordinate. The chemical reaction rate can be boosted, stirred, or decelerated with this unconventional tool. Here, we used the idea of cooperative vibrational strong coupling of solute and solvent molecules to enhance the chemical reaction rate. This process is called cavity catalysis. Different derivatives of p-nitrophenyl benzoate (solute) and isopropyl acetate (solvent) are cooperatively coupled to an infrared Fabry-Perot cavity. The apparent reaction rates are increased by more than six times at the ON resonance condition, and the rate enhancement follows the lineshape of the vibrational envelope. Very interestingly, strong coupled system doesn\u27t follow a linear free-energy relationship. The nonlinear rate enhancement can be due to the reshuffling of energy distribution between the substituents and the reaction center. Thermodynamic parameters suggest an entropy-driven process for the coupled molecules. The free energy of activation decreased by 2-5 kJ/mol, suggesting a clear role of vibrational strong coupling in catalyzing the reaction. Here, the enthalpy of the system compensates for the entropy by preserving the isokinetic relationship. These findings will help further understanding of chemical reaction control in polariton chemistry