Solvent Effect in Liquid-Phase Hydrogenation of Toluene

Improving reproducibility through condition-based sensitivity assessments: application, advancement and prospect

The fluctuating reproducibility of scientific reports presents a well-recognised issue, frequently stemming from insufficient standardisation, transparency and a lack of information in scientific publications. Consequently, the incorporation of newly developed synthetic methods into practical applications often occurs at a slow rate. In recent years, various efforts have been made to analyse the sensitivity of chemical methodologies and the variation in quantitative outcome observed across different laboratory environments. For today's chemists, determining the key factors that really matter for a reaction's outcome from all the different aspects of chemical methodology can be a challenging task. In response, we provide a detailed examination and customised recommendations surrounding the sensitivity screen, offering a comprehensive assessment of various strategies and exploring their diverse applications by research groups to improve the practicality of their methodologies.

Soybean Oil Treatment Using the Dissolving Curve Equation of Hydrogen

The solubility of hydrogen in n-hexane was determined using a homemade reactor. The solubility of hydrogen in soybean oil was established using the Peng-Robinson (PR) equation of state and the van der Waals mixing rule. The curve equation established a linear relationship between the solubility of hydrogen in oil and the number of moles of hydrogen in the reactor. Under the optimal temperature and catalyst, the relationship between the hydrogen consumption of the hydrogenation of oil and fat and the TFAs formed in the oil was determined. When the reaction pressure exceeded 3.0 MPa, the hydrogenation of oil was consumed. The amount of hydrogen, the rate of hydrogenation, and the change in the TFAs all stabilized. Therefore, the pressure of the general hydrogenation reaction should not exceed 3.0 MPa. This result provides a quick and simple method for controlling TFAs in oils and fats for industrial applications.

Noble Metal Nanoparticles Stabilized by Hyper-Cross-Linked Polystyrene as Effective Catalysts in Hydrogenation of Arenes

This work is addressing the arenes' hydrogenation-the processes of high importance for petrochemical, chemical and pharmaceutical industries. Noble metal (Pd, Pt, Ru) nanoparticles (NPs) stabilized in hyper-cross-linked polystyrene (HPS) were shown to be active and selective catalysts in hydrogenation of a wide range of arenes (monocyclic, condensed, substituted, etc.) in a batch mode. HPS effectively stabilized metal NPs during hydrogenation in different medium (water, organic solvents) and allowed multiple catalyst reuses.

Unraveling Toluene Conversion during the Liquid Phase Hydrogenation of Cyclohexene (in Toluene) with Rh Hybrid Catalysts

Monitoring hydrogen consumption has allowed studying the progress of the liquid phase hydrogenation of cyclohexene in toluene with Rh SILP (supported ionic liquid phase) catalysts prepared by the immobilization of the [{RhCl(cod)}2] complex on different carbon materials. An excess of hydrogen consumption with respect to the required amount for cyclohexene hydrogenation was registered and related with the solvent (toluene) hydrogenation. The study carried out led to unraveling the extent of toluene hydrogenation and to determining if the rate of this reaction is affected by the properties of the carbon material used as support. The results revealed that the Rh SILP catalysts we prepared showed acceptable toluene conversion, with 100% selectivity to the total hydrogenated product, and that the effect of the carbon support is the same as for cyclohexene hydrogenation.

Raman spectroscopic study of cyclohexane at pressures below 1000MPa

At present, the room temperature freezing pressure of cyclohexane is still uncertain, and the phase transition pressure of solid I - solid III is not reliable at ambient temperature. In this work, we have performed a Raman spectroscopic study of cyclohexane in a Moissanite anvil cell at pressures below 1000MPa at 25°C, and analyzed the characteristic of Raman brands ν_s(CH₂), ν_as(CH₂) and ν_b(Ring). Two phase transition pressures 80MPa and 550MPa were determined by a quartz pressure gauge, and they are the room temperature freezing pressure of cyclohexane and the phase transition pressure of solid I to solid III, respectively. Furthermore, from the phase diagram of cyclohexane, it is inferred that pressure plays an important role on the stability of cyclohexane as the main constituent of oil, and it can be beneficial to understanding the formation, migration and preservation of petroleum in subterranean rock strata.

Improving mass-transfer in controlled pore glasses as supports for the platinum-catalyzed aromatics hydrogenation

Mass-transfer improvement in the Pt-catalyzed aromatics hydrogenation by increasing the pore width of controlled pore glasses as supports.

In situ high-pressure and high-temperature experiments on n-heptane

The Raman spectroscopy of n-heptane was investigated in a moissanite anvil cell at ambient temperatures and a diamond anvil cell under pressures of up to ~2000 MPa and at temperature range from 298 to 588 K. The results show that at room temperature the vibration modes, assigned to the symmetric and antisymmetric stretching of CH(3) and CH(2) stretching, shifted to higher frequency according to quasi-linearity with increasing pressure, and a liquid-solid phase transition occurred at near 1150 MPa. The high-temperature solidus line of n-heptane follows a quadratic function of P = 0.00737T(2) + 5.27977T - 1195.76556. Upon phase change, fitting the experimental data obtained in the temperature range of 183∼412 K to the Clausius-Clapeyron equation allows one to define the thermodynamic parameters of n-heptane of dP/dT = 0.01474T + 5.27977.

Synthesis and catalytic properties of soluble platinum nanoparticles protected by a thiol monolayer

Several new platinum monolayer protected clusters (MPCs) have been synthesized and characterized. Two methods of platinum reduction were used depending on the solubility of the thiol: sodium borohydride for the water-soluble thiols and lithium triethylborohydride for the organic soluble thiols. In general, reactant solutions containing a 1:1 thiol/Pt ratio yielded the best particles in a single-phase reaction. Higher thiol/Pt ratios produced lower yields of MPCs, while much lower ratios produced gray-black precipitates. The Pt MPCs were used as catalysts to hydrogenate allyl alcohol to propanol by reducing the carbon-carbon double bond. The Pt-mercaptoammonium MPCs were also used as catalysts in the hydrogenation of maleic acid to succinic acid. Differences in the catalytic hydrogenation rates among the various monolayer coatings for MPCs are attributed to the variations in ligand chain length, branching, charged functional groups, packing density, and core size.