kinetics

Regularities of low-waste technology of wastewater treatment by coagulation method

Mechanisms of wastewater purification from surface-active substances and of sulphuric acid dissolution of iron-containing sludge formed during the previous process have been established. Kinetic regularities of metal-containing sludge dissolution in sulphuric acid have been investigated. Kinetic equation which adequately presents the experimental data has been proposed; constants of this kinetic equation have been calculated.

Alkylation of 2,6-di-tert-Butylphenol with Methyl Acrylate Catalyzed by Potassium 2,6-di-tert-Butylphenoxide

The kinetics of catalytic alkylation of 2,6-di-tert-butylphenol (ArOH) with methyl acrylate (MA) in the presence of potassium 2,6-di-tert-butylphenoxide (ArOK) depends on the method for the preparation of ArOK. The reaction of ArOH with KOH at temperatures > 453 K affords monomeric ArOK, which properties differ from those in the case of potassium 2,6-di-tert-butylphenoxide synthesized by the earlier methods. The regularities of ArOH alkylation depend on the ArOK concentration, the ArOH:MA ratio, and the effect of microadditives of polar solvents.

Potassium and Sodium 2,6-Di-tert-Butyl Phenoxides and their Properties

The determining factor of the reaction of 2,6-di-tert-butylphenol with alkaline metal hydroxides is temperature, depending on which two types of potassium or sodium 2,6-di-tert-butyl phenoxides are formed with different catalytic activity in alkylation of 2,6-di-tert-butylphenol with methyl acrylate. More active forms of 2,6-But2C6H3OK or 2,6-But2C6H3ONa are synthesized at temperatures higher than 433 K representing predominantly monomers of 2,6-di-tert-butylphenoxides which produce dimers when cooling.

The Characterization of Novel Biodegradable Blends Based on Polyhydroxybutyrate

the water transport and morphology (TEM data) shows the impact of polymer component ratio on the regulating water flux in a hydrophobic matrix. To elucidate the role of hydrophilicity of the second component presented in the PHB blends, we studied the PHB/PA blends where PA is the polyamide resin composed of statistical copolymer of hexamethyleneadipinate and ε-caprolactam in the ratio of 1:1. The complex of techniques including DCS and FTIR-imaging (for T-scale) demonstrates the interaction between PHB and PA in the temperature ranges of crystallization and melting.

Light Curable Dental Composites – Kinetics by Plasma and Halogen Lamps

A series of commercial dental composites curable by visible light have been investigated and compared in terms of their photoreactivity thanks to the photocalorimetry technique by using two different types of lamps, a conventional lamp (halogen lamp) from ESPE and a plasma lamp, Apollo 98E manufactured by DMDS. In terms of kinetics, dental composites cure in just a few seconds with plasma lamp compared to 20-40 s with halogen lamp allowing dentists to save time.

Peculiarities of Peroxide-Containing Reactive Copolymers Synthesis

This work deals with the study of radical copolymerization of higher esters of (meth)acrylic acid with peroxide monomer, 5-tert-butylperoxy-5-methyl-2-hexene-3-yne showing the properties of a weak inhibitor. Due to the mentioned and other features of investigated process, the composition of obtained copolymer cannot be adequately described with known Mayo-Lewis and Scaits equations. The analysis of kinetic data has allowed to propose differential equation of copolymer composition for investigated systems. A technique of quasi-stationary concentrations was not used during its derivation.

Phenol-Formaldehyde Resins of Novolac Type with Unsaturated Side Bonds

The reaction between novolac phenol-formaldehyde resin and glycidylmethacrylate has been studied in the presence of potassium hydroxide and the synthesis procedure of phenol-formaldehyde resin with unsaturated side bonds has been suggested. The effective rates and activation energy of the mentioned reaction have been calculated. The structure of synthesized resin was confirmed by IR-spectroscopy. The synthesized resin may be used as active component of polymeric blends based on ED-20 industrial epoxy resin, its peroxy derivative (PO) and TGM-3 oligoesteracrylate.

Chemical Modification of ED-24 Epoxy Resin by Adipic Acid

The possibility of epoxy resin carboxy-containing derivative (CDER) obtaining has been studied on the basis of dianic epoxy resin ED-24 and adipic acid (AA). The synthesized CDER contains epoxy and carboxy groups at the same time. Used catalysts were benzyltriethylammonium chloride (BTEACh); 1,4-diazobicyclo[2,2,2]octane; N,N-dimethylaminopyridine; 18-Crown-6, potassium hydroxide, triethylamine and 18-Crown-6+ZnCl2 catalytic system. The effect of the catalyst nature and amount, reagents ratio, process temperature and time on the reaction proceeding between ED-24 and AA has been determined.

Mechanism of Catalytic Alkylation of 2,6-di-tert-Butylphenol by Methyl Acrylate

The determining factor of the reaction of 2,6-di-tert-butylphenol with alkaline metal hydroxides is temperature, depending on which two types of potassium or sodium 2,6-di-tert-butyl phenoxides are formed with different catalytic activity in the alkylation of 2,6-di-tert-butylphenol with methyl acrylate. More active forms of 2,6-But2C6H3OK or 2,6-But2C6H3ONa are synthesized at temperatures higher than 433 K and represent predominantly monomers of 2,6-di-tert-butyl phenoxides producing dimers on cooling.