tamine a t a rate which suggests that activated glutamic Harry L. Conley, Jr., for performing the pH-Stat runs. acid may be bound to the enzyme in a y-ester link.The pH-rate profiles and the effect of structure on reactivity for the hydrolysis of Schiff bases derived from benzophenone and aliphatic amines are similar to those previously obtained for the hydrolysis of benzylidene-1,l-dimethylethylamines. The second-order rate constant for the attack of hydroxide ion on the cationic Schiff base, benzhydrylidenedimethylammonium ion, i s similar to those calculated from the first-order rate constants for the pH-independent reaction above p H 9 for the attack of hydroxide ion on protonated benzhydrylideneamines. This finding, together with the observed lack of dependence of the first-order rate constants for the pH-independent reaction on the nature of polar substituents, strongly suggests that this reaction does involve the attack of hydroxide ion on the protonated substrates rather than the attack of water on the free base of the substrate,The attack of water on benzhydrylidenedimethylammonium ion is subject to general base catalysis by carboxylate ions.Under conditions in which the Schiff bases exist as the conjugate acids, the reactivity of Schiff bases derived from benzophenone and ammonia, methylamine, and dimethylamine, toward hydroxylamine, methoxyamine, semicarbazide, and water decreases with increasing methyl substitution on nitrogen. Values of p + for the reaction of water, hydroxylamine, and methoxyamine with the conjugate acids of a series of substituted benzhydrylidenemethylatnines are 1.1, 0.92, and 0.96, respectively.The similarity of the effect of structural alteration in either t h e amine or carbonyl component of the Schiff base on reaction rates for the reaction with water, for which attackof the nucleophilic reagent is rate determining, and for the reactions with the amines suggests that the attack of the amines is also rate determining. This suggestion is also supported by the finding that the aminolysis reactions, like the hydrolysis reaction, are subject to general base catalysis. The reaction of a series of substituted benza Idehyde semicarbazones with hydroxylamine and the reaction of a series of substituted benzaldehyde oximes with semicarbazide are dependent upon acid catalysis, Both sets of data are correlated by Hammett p-values of -1.7.The Brgmsted p-value for this reaction is 0.27.The pK, values for the conjugate acids of benzaldehyde oximes have been determined.

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Naval and private shipyards generate thousands of tons of used blast grit annually and dispose of it in landfills. Also, thousands of steel bridges in the United States are on a repaint maintenance schedule that requires grit blasting for surface preparation; this used grit also goes to landfills. However, for environmental reasons it is becoming prohibitively expensive to landfill used blast grit containing paint residues. The Institute of Gas Technology (IGT) has conducted test work to develop a process to clean used blast grit for reuse. Four reclaimer feasibility tests were conducted with used blast grit from the Long Beach Naval Shipyard. The results of these tests revealed that the organic material component of the used grit was fully oxidized to carbon dioxide and water. Some of the metallic oxides of copper, zinc, titanium, and lead from the used grit were largely elutriated into a cyclonic collector. The calcined (reclaimable) fraction from this test work amounted to approximately 95 percent of the used grit charged. Major oxide and organic component analyses revealed no significant general chemical difference between the virgin and reclaimed grit.

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