Devdopment of the Monolith Froth Reactor for Catalytic Wet Oxidation of CELSS Mo_
The aqueous phase oxidation of acetic acid, used as a model compound for the treatment of CELSS (Controlled Ecological Life Support System) waste, was carried out in the monolith froth reactor which utilizes two-phase flow in the monolith channels. The catalytic oxidation of acetic acid was carried out over a Pt/AI.,O_ catalyst, prepared at The University of Tulsa, at temperatures and pressures below the critical point of water. The effect of ex'temally controllable parameters (temperature, liquid flow rate, distributor plate orifice size, pitch, and catalyst distance from the distributor plate) on the rate of acetic acid oxidation was investigated. Results indicate reaction rate increased with increasing temperature and exhibited a maximum with respect to liquid flow rate. The apparent activation energy calculated from reaction rate data ,,,,,as 99.7 kJ/mol. This value is similar to values reported for the oxidation of acetic acid in other systems and is comparable to intrinsic values calculated for oxidation reactions. The "kinetic data were modeled using simple power law kinetics.
Bubble-train flow in capillaries of circular and square cross section
Abstract Ceramic monoliths first developed for their use in automotive catalyst, are used now to perform three-phase, catalyzed reactions. The large mass transfer rates achieved within this type of reactor are the result of large interfacial area and very thin diffusion paths. These enhanced mass transfer rates are credited to the presence of well-developed bubble-train flow. Bubble-train flows consist of trains of long bubbles separated by liquid slugs. The interfacial area is the area of the bubbles and the thin films are the result of the squeezing action of the bubbles as they overtake the liquid slugs. The objective of this paper is to predict the main mass transfer parameters, such as bubble size and shape, bubble velocity, and volume fraction of gas inside capillaries of circular or square cross section, on the basis of the superficial flow rates of gas and liquid in the feed. Experiments are reported here on bubble train flow inside capillaries of circular and square cross section for a large range of capillary numbers. A mass balance model was developed to allow the computation of flow parameters using an iteration scheme.
Catalytic removal of tert-butyldimethylsilyl (TBS) ether by PVP-I
Abstract A mild, efficient and rapid protocol the deprotection of alcoholic TBDMS ethers using PVP-1 as catalyst in methanol, the procedure of deprotection of various TBDMS ethers were found to be very convenient, easy work-up, high yielding.