Experimental and Computational Study of the Thermal Decomposition of 3‐Methyl‐3‐buten‐1‐ol in m‐Xylene Solution

An experimental study of the thermal decomposition of a β‐hydroxy alkene, 3‐methyl‐3‐buten‐1‐ol, in m‐xylene solution, has been carried out at five different temperatures in the range of 513.15–563.15 K. The temperature dependence of the rate constants for the decomposition of this compound in the corresponding Arrhenius equation is given by ln k (s^?1) = (25.65 ± 1.52) ? (17,944 ± 814) (kJ·mol^?1)·T^?1. A computational study has been carried out at the M05–2X/6–31+G(d,p) level of theory to calculate the rate constants and the activation parameters by the classical transition state theory. There is a good agreement between the experimental and calculated rate constants and activation Gibbs energies. The bonding characteristics of reactant, transition state, and products have been investigated by the natural bond orbital analysis, which provides the natural atomic charges and the Wiberg bond indices. Based on the results obtained, the mechanism proposed is a one‐step process proceeding through a six‐membered cyclic transition state, being a concerted and slightly asynchronous process. The results have been compared with those obtained previously by us (Struct Chem 2013, 24, 1811–1816) for the thermal decomposition of 3‐buten‐1‐ol, in m‐xylene solution. We can conclude that in the compound studied in this work, 3‐methyl‐3‐buten‐1‐ol, the effect of substitution at position 3 by a weakly activating CH₃ group is the stabilization of the transition state formed in the reaction and therefore a small increase in the rate of thermal decomposition.     

Estimation of the Diffusion Coefficient of Doxorubicin Molecules in a Water Solution in the Volume of a Porous Carrier Medium

Russian Physics Journal - An experimental investigation of the phenomenon of diffusion of the solution components in nanosized pores is extremely difficult and in certain cases impossible. An...     

Secondary fibrous materials from cardboard and paper production and consumption waste

Some information characterizing wastepaper, including utilization rates, technical data of different fiber grades, and waste paper processing technologies, is presented in the article. Wastepaper obtained from different sources such as cardboard and paper production, production of various goods (e.g. printing companies), and cardboard and paper consumption (e.g. household waste) is also described.     

Structural and Kinetic Aspects of Blood Plasma Protein Adsorption on the Surface of Hydrophobic Polymers

Abstract

Due to the wide use of polymers in medicine, researchers are required to solve a very important problem–to understand the interaction between materials of nonphysiological origin and the surrounding biological liquids, and tissues, particularly blood.     

Formaldehyde interaction with adsorbed oxygen on open-circuit platinum electrodes in aqueous sulfuric acid solutions

The open circuit potential transients and cathodic potentiodynamic pulses were measured upon formaldehyde (methylene glycol) interaction with pre-adsorbed oxygen (O_ads) on Pt/Pt and pc Pt electrodes in aqueous sulfuric acid solutions. The slowest interaction of CH₂(OH)₂ with O_ads was observed in the high coverage range of the electrode surface (θ_O ～ 0.2 0.8 to 1). The process rate in this range is determined by the direct reaction of O_ads with CH₂(OH)₂ molecules from the bulk solution. In the middle surface oxygen coverage range (θ_O 0.2 to 0.8), CH₂(OH)₂ interaction with O_ads takes place by the mechanism of “conjugated reactions”. The kinetic parameters of reactions for CH₂(OH)₂, HCOOH, and CH₃ OH were compared. The rate of CH₂(OH)₂-O_ads interaction on Pt electrodes in the high oxygen coverage range was found higher by an order of magnitude than that of HCOOH and by two orders of magnitude than in the case of CH₃OH.