Dissolution Enthalpy and Entropy of Thiourea in Ethanol at 292–320 K

The dissolution enthalpy and entropy of thiourea in ethanol have been calculated from solubilities of thiourea in ethanol at the mass fractions 0.54–0.88 and temperatures 292–320 K. The data can be used for the synthesis of isopropyl mercaptan.     

Synthesis of Crystalline Nanosized Titanium Dioxide via a Reverse Micelle Method at Room Temperature

Crystalline TiO2 nanoparticles were synthesized by hydrolysis of titanium tetrabutoxide in the presence of hydrochloric acid in Np-5(lgepal CO-520)/ cyclohexane reverse micelle solution at room temperature.Pure rutile nanoparticles were obtained at an appropriate acid concentration.The influences of various reaction conditions such as the concentration of acids,water content value (2=[H2O]/[Np-5]) on the formation,erystal phase,morphology,and size of the TiO2 particles were investigated.     

Facile Synthesis of Ferrocenylenones in Free Solvent at Room Temperature

The rate of formation of aldol condensation products by being ground acetylferrocene and various aromatic aldehydes without solvent was dramatically enhanced comparing to ,the conventional methods. The yield is high (84 % - 96 %) at room temperature.     

Selective Anodic Dissolution of Ag–Zn Alloys in the Eutectic Melt of Alkali Metal Chlorides at 300°С

Russian Journal of Electrochemistry - The peculiarities of electrochemical dealloying of two homogeneous Ag–Zn alloys in the (LiCl)0.57(CsCl)0.26(KCl)0.17 melt are studied. The zinc content...     

Photo-Induced Ruthenium-Catalyzed C−H Benzylations and Allylations at Room Temperature

The ruthenium-catalyzed synthesis of diarylmethane compounds was realized under exceedingly mild photoredox conditions without the use of exogenous photocatalysts. The versatility and robustness of the ruthenium-catalyzed C−H benzylation was reflected by an ample scope, including multifold C−H functionalizations, as well as transformable pyrazoles, imidates and sensitive nucleosides. Mechanistic studies were indicative of a photoactive cyclometalated ruthenium complex, which also enabled versatile C−H allylations.     

Facile Fabrication of Surfactant‐Modified ZnS Hollow Spheres at Room Temperature and Its Tribological Properties in Liquid Paraffin

This article presents a facile surfactant‐assisted route to the fabrication of ZnS hollow spheres with diameter of about 0.5～1 µm in ethanol at room temperature. The surfactant quaternary ammonium salt of 2‐undecyl‐1‐dithioureido‐ethyl‐imidazoline (SUDEI) prepared in our lab acts as surface‐modifying agent, morphology‐controlling agent and stabilizing agent in the whole procedure. TEM, SEM, XRD, EDXA, UV‐vis, and FTIR were used to characterize the ZnS products. The influences of reaction conditions were discussed while a formation mechanism was proposed to explain this peculiar morphology. The ZnS hollow spheres product is of excellent dispersion capacity and stability in liquid paraffin (LP) and the tribological properties of LP containing ZnS hollow spheres were studied with an Optimol SRV (SRV is the abridged name for German Schwingung, Reibung, Verschleiss) oscillating friction and wear tester, showing excellent anti‐wear and friction‐reducing performances. The action mechanism of the ZnS hollow spheres in LP was also investigated and discussed.     

An Efficient Solid Acid Promoted Synthesis of Quinoxaline Derivatives at Room Temperature

Quinoxaline derivatives have been synthesized in a very short time with excellent yields by the condensation of 1,2-diamines with aliphatic or aromatic 1,2-dicarbonyl compounds or benzilmonoxime in the presence of silica sulfuric acid as a very inexpensive solid acid catalyst at room temperature. The recovery and reuse of the catalyst are also satisfactory.     

Ethanol Gas Sensor Based on γ-Fe2O3 Nanoparticles Working at Room Temperature with High Sensitivity

Improving the sensing sensitivity and lowering the working temperature are the critical issues for the practical application of gas sensors. For a gas sensor, the sensing materials play important roles in determining the sensing properties. In the present work, γ-Fe₂O₃ microspheres composed of nanoparticles were successfully fabricated by a typical facile hydrothermal process and a following annealing treatment. Interestingly, the as-synthesized γ-Fe₂O₃ microspheres showed excellent sensing properties for the detection of ethanol gas with high sensitivity, and especially working temperature as low as room temperature. The gas sensing results showed that at the optimal operating temperature (200 °C), the response intensity of γ-Fe₂O₃ microspheres for 1000 ppm ethanol gas could reach 74.6 and the limit of detection (LOD) was about 0.026 ppm. At room temperature, the γ-Fe₂O₃ microspheres still demonstrated a good response to different concentrations of ethanol gas from 1 to 1000 ppm, with a very good selectivity over other gas species and a good stability. This study indicated that the γ-Fe₂O₃ phase could be a type of promising room-temperature gas sensing material for ethanol gas detection.     

Electrochemical Deposition of NiFe Alloy at a Temperature of 70°C

Russian Journal of Electrochemistry - The heating of chloride electrolyte to a temperature of 70°C excludes anomalous codeposition of NiFe alloy components as a result of a change of the...     

Facile Synthesis of Gold Nanoplates by Citrate Reduction of AuCl4^- at Room Temperature

Metal and semiconductor nanoparticles with nonspherical shapes, such as wires1, cubes2,3 and belts4, have been drawing a great interest in scientific community as a result of their physical and chemical properties being distinctly different from conventio…     

Proving and Probing the Presence of the Elusive C−H⋅⋅⋅O Hydrogen Bond in Liquid Solutions at Room Temperature

Hydrogen bonds (H bonds) play a major role in defining the structure and properties of many substances, as well as phenomena and processes. Traditional H bonds are ubiquitous in nature, yet the demonstration of weak H bonds that occur between a highly polarized C−H group and an electron-rich oxygen atom, has proven elusive. Detailed here are linear and nonlinear IR spectroscopy experiments that reveal the presence of H bonds between the chloroform C−H group and an amide carbonyl oxygen atom in solution at room temperature. Evidence is provided for an amide solvation shell featuring two clearly distinguishable chloroform arrangements that undergo chemical exchange with a time scale of about 2 ps. Furthermore, the enthalpy of breaking the hydrogen bond is found to be 6–20 kJ mol⁻¹. Ab-initio computations support the findings of two distinct solvation shells formed by three chloroform molecules, where one thermally undergoes hydrogen-bond making and breaking.     

Temperature and Heat Flow Calibration of A DSC-instrument in the Temperature Range Between −100 and 160°C

Thermoanalytical instruments are extensively used in R&D as well as in industrial quality control. A quantitative analysis of the data of a thermoanalytical measurement requires a careful calibration of the instrument. In differential scanning calorimetry (DSC) the quantities that have to be calibrated are the temperature and the heat flow. These two quantities are usually calibrated by evaluating melting or solid-solid transitions of some reference materials with well known transition enthalpies and temperatures. In this contribution we investigate temperature and heat flow calibration in the temperature range between −100 and 160°C. We included 9 different samples for the analysis and established some general rules for the calibration process. As a result we found that with a well calibrated instrument the heat flow can be measured with 90% confidence to about ± 3% accuracy in this temperature range. With respect to temperature calibration we find that accuracies of ±0.8°C (90% confidence) may be expected. These values represent general accuracy limitations of DSC’s due to varying heat transfer conditions within the samples. This revised version was published online in July 2006 with corrections to the Cover Date.     

Kinetics of Protonolysis of o-Substituted Phenylmercuric Chlorides by HCl(NaI) in Ethanol

Yadavetalhaveexaminedthereactionsbetweeniodineando-XC6H4HgCl(X=H,0H,CH3,N0z)inethanol,foundthatthetotalorderofthereacti0nwastwo,andthattheorderoftherateconstantsofthesedifferentderivativesofphenylmercuricchlorideis0H>H>CH3>NO2.Theyprop0sedthattheproximityofCH3grouptoHgCIgroup(orthoposition)isresponsibleforitsreverseeffect1.ButinourearlierresearhesonprotonolysisofarylmercuricchloridesbyHCl(NaI)inaqueousdio....2',n0obvioussterichindranceofo-substituentswasobserved,instead,abnormalelec…     

Substitution Reactions by Azide and Thiocyanide Anions in Room Temperature Ionic Liquids

Conducted in the ionic liquids,activated and inactivated halides,acyl chlorides,tosylate and bezotriazolyl acylates were converted to corresponding azide and thiocyanide compounds in high yields under mild conditions.     

“Self-Lockable” Liquid Crystalline Diels–Alder Dynamic Network Actuators with Room Temperature Programmability and Solution Reprocessability

Novel main-chain liquid crystalline Diels—Alder dynamic networks (LCDANs) were prepared that exhibit unprecedented ease for actuator programming and reprocessing compared to existing liquid crystalline network (LCN) systems. Following cooling from 125 °C, LCDANs are deformed with aligned mesogens self-locked at room temperature by slowly formed Diels–Alder (DA) bonds, which allows for the formation of solid 3D actuators capable of reversible shape change, and strip walker and wheel-capable light-driven locomotion upon either thermally or optically induced order–disorder phase transition. Any actuator can readily be erased at 125 °C and reprogrammed into a new one under ambient conditions. Moreover, LCDANs can be processed directly from melt (for example, fiber drawing) and from solution (for example, casting tubular actuators), which cannot be achieved with LCNs using exchangeable covalent bonds. The combined attributes of LCDANs offer significant progress toward developing easily programmable/processable LCN actuators.     

Rapid Synthesis of Lead Oxide Nanorods by One-step Solid-state Chemical Reaction at Room Temperature

A simple and facile method was reported to synthesize lead oxide nanorods. Nanorods of lead oxide were obtained directly from grinding solid metal salt and sodium hydroxide in agate mortar with the assistance of a suitable nonionic surfactant in only one step, which is different from the result of hydroxide in solution. The product has been characterized by XRD, TEM and SEM. The formation mechanism of rod-like morphology is discussed and the surfactant plays an important soft-template role in modifying the interface of solid-state reaction and according process of rod-formation.     

Reactions in the magnesium propionate-boric acid-water system at 50 and 60°C

The Mg(CH₃CH₂COO)₂-H₃BO₃-H₂O section of the MgO-B₂O₃-C₆H₁₀O₃-H₂O quaternary system was studied at 50 and 60°C using the isothermal solubility method and measurements of the density, pH, and refractive index of saturated solutions. A chemical reaction with the formation of MgB₄O₇ · 7H₂O and MgB₆O₁₀ · 8H₂O was established to proceed in the system. The identity of precipitated solid phases was confirmed by chemical analysis, derivatography, and IR spectroscopy.     

Synthesis of New Multibenzo Oxygen–Sulfur Donor Macrocycles Containing Lactams at Room Temperature

Some new oxygen–sulfur, multibenzo macrocyclic ligands containing amide groups have been prepared using the macrocyclization process with the reaction of 2,2′-thiobis-[4-methyl(2-aminophenoxy)phenyl ether] as a symmetrical diamine with appropriate dicarboxylicacid dichlorides in moderate yields. This macrocyclization led to the formation of di- and tetramide macrocycles. These reactions were routinely carried out at ambient temperature in CH₂Cl₂ as solvent in high dilution without template effect conditions. It is found that sulfur the atom affects the rigidity of the macrocycles and diastereotopicity of nuclei in the ring of these series of macrocyclic compounds.     

Trifluoromethylation of Allenes: An Expedient Access to α-Trifluoromethylated Enones at Room Temperature

A silver(I) catalyzed regioselective trifluoromethylation of allenes using Langlois's salt (NaOSOCF₃) is demonstrated. This transformation enables direct expedient access to α-trifluoromethylated acroleins, which are valuable synthons for a number of pharmaceuticals and agrochemicals containing vinyl-CF₃ moieties. Versatility of this trifluoromethylation method has been established with good yield and excellent regioselectivity. Preliminary experiments and computational studies were carried out to elucidate the mechanistic insight of this protocol.