Reactivities of copper-germanium alloys in the direct synthesis of dimethyldichlorogermane

The activities of the single phase alloys a (Ge in Cu), ζ (Cu5Ge), and ε{lunate} (Cu3Ge) in the reaction with methyl chloride to form methylchlorogermanes were measured at 426.7 °C. The alloys displayed essentially the same reactivity when compared on the basis of the same number of germanium atoms exposed to methyl chloride. Selectivity for (CH3)2GeCl2 approached 100% at 0% conversion of germanium, thus supporting the ionic mechanism of Voorhoeve. The extent of cracking of methyl chloride could be correlated with the fraction of the surface estimated to consist of copper atoms not involved in the synthesis of methylchlorogermanes. Removal of copper from thin surface layers, probably as CuCl, was confirmed by X-ray analysis in the case of the α phase. Mechanical mixtures of alloys and free germanium showed greatly enhanced reactivities which could be explained only by the creation of additional reaction sites on the surfaces of the free germanium particles. © 1973

Attrition in a Liquid Fluidized Bed Bioreactor

Attrition of porous alumina spheres in a liquid fluidized bed was measured at three different liquid velocities. Attrition rate varied with superficial fluid velocity in a manner different from that reported for gas fluidized beds. An attempt was made to correlate the attrition rate with the number of particle collisions in the bed. The latter was estimated by a model based on an analogy with the kinetic theory of gases. The model failed to predict the measured increase of attrition rate with superficial liquid velocity. Reasons for the failure of the model are discussed. © 1988, American Chemical Society. All rights reserved

Two-position control of a batch prepolymerization reactor

The optimal control policy for the batch polymerization of methyl methacrylate up to 10% monomer reacted was determined, assuming that jacket heat transfer fluid was available at two fixed temperature levels and that the reactor temperature could not exceed an upper bound. At the highest initiator concentration full heating was optimal, while at lower initiator concentrations the optimal policy called for a single switch from full heating to full cooling. At the lowest initiator concentration with high initial temperature, an infinite number of switches would be required. © 1969, American Chemical Society. All rights reserved

Wet oxidation of glucose

Wet oxidation is used to oxidize organic substances at a controlled rate in an aqueous medium at elevated temperatures and pressures. Aqueous glucose solutions were oxidized with pure oxygen at four different temperatures in the range 176.7°C to 260.0°C, and at an oxygen pressure of 2.3 MPa. Three distinct stages of wet oxidation were found — induction, rapid oxidation, and slow oxidation. During the rapid oxidation period the reaction was assumed to be confined to a thin liquid layer next to the gas‐liquid interface. The activation energy for the rapid oxidation period was estimated to be 130 ± 20 kJ/mol. Acetic acid was found to accelerate the rate of wet oxidation of glucose only slightly