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497 results on '"Chavadej, Sumaeth"'

197. Dissolution of Soap Scum by Surfactants. Part III. Effect of Chelant Type on Equilibrium Solubility and Dissolution Rate of Calcium and Magnesium Soap Scums in Various Surfactant Systems.

Author

Itsadanont, Sawwalak, Theptat, Prariyada, Scamehorn, John F., Soontravanich, Sukhwan, Sabatini, David A., and Chavadej, Sumaeth

Subjects
SURFACE active agents, DISSOLUTION (Chemistry), ANIONIC surfactants, SOAP, CHELATING agents
Abstract

Soap scum can be effectively removed by using an appropriate surfactant with a chelating agent at a high solution pH. The equilibrium solubilities and dissolution rates of two model soap scums [calcium stearate and magnesium stearate: Ca(C) and Mg(C)] were investigated in aqueous solutions containing three different types of surfactants [methyl ester sulfonate (MES) as an anionic surfactant; alcohol ethoxylate (EO9) as a nonionic surfactant; and dimethyldodecylamine oxide (DDAO) as an amphoteric surfactant] in the presence of different biodegradable chelants: trisodium ethylenediamine disuccinic acid (NaEDDS) and tetrasodium glutamate diacetic acid (NaGLDA) compared with disodium ethylenediamine tetraacetate (NaEDTA), a chelant with poor biodegradability. The highest equilibrium solubility and dissolution rate of either soap scum were observed at high pH in the DDAO system with NaGLDA. In addition, the calcium soap scum had a similar to higher equilibrium solubility and a higher dissolution rate constant as compared with the magnesium soap scum. [ABSTRACT FROM AUTHOR]

Published
2015
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198. Micro-kinetic modeling of the catalytic dehydration of 1-decanol over precipitated γ-AlO.

Author

Echaroj, Snunkheam, Santikunaporn, Malee, and Chavadej, Sumaeth

Abstract

The mechanisms of the dehydration reaction of 1-decanol to 1-decene over precipitated gamma-alumina (γ-AlO) by means of the micro-kinetic modeling approach were investigated. Experimental data were collected in the reaction temperature range of 533-608 K, while the retention time was varied from 0.029 to 0.15 h. The γ-AlO catalyst was synthesized using a traditional precipitation method. The yield of both internal olefins and 1-decene increased with increasing reaction temperature. Conversely, the yield of di- n-decyl ether decreased with increasing temperature. An increase in retention time increased the yield of 1-decene and internal olefins. These experimental data correlated well with the rate equation that assumes the formation of 1-decene to be reversible and a dual-site reaction. It is reasonable to state that internal isomerization is reversible with a single-site reaction. The apparent activation energy for the dehydration reaction of 1-decanol to 1-decene, obtained from the Arrhenius plot data, was 102 ± 2 kJ/mol. [ABSTRACT FROM AUTHOR]

Published
2015
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