KINETIC MODELING OF SYNTHESIS OF BUTYL POLYGLYCOSIDES
Alkyl polyglycosides (APG) has been paid more and more attention in surfactant industry, not only because APG has high surface activity, but also because it is not hazardous, not irritant, well biodegradable and is made from naturally occurring renewable raw materials, i.e., starch or glucose. Therefore, APG is called as "surfactant for 21st century", and technical studies on synthesis and manufactures of APG have been developed rapidly since 1990s, but there is a lack of study on reaction kinetics of APG. The reaction kinetics of synthesis of butyl polyglycosides was studied based on "shrinking core model".A solid-liquid interface reaction model, which contains a step of mass transfer resistance, was proposed. In "shrinking core model", only the chemical reaction taking place in the solid-liquid reaction system is involved.Under condition of optimal technology parameters for the synthesis of butyl polyglycosides,in which reaction temperature is in the range of 90-110?℃, and stirrer rotation speed is from 6.67-13.33?r·s -1 ,mass transfer resistance can not be ignored.The ratio of chemical reaction rate constant to mass transfer coefficient,namely, k r/ k B,obtained by means of solid-liquid interface model, can directly reflect the relative rate of chemical reaction to mass transfer. At the same time, the chemical reaction kinetic parameters were obtained. The results suggest that solid-liquid interface reaction model is more accurate than the "shrinking core model" in describing the formation of butyl polyglycosides which is the first step of synthesis of APG.