Physical Sciences and Mathematics Commons^™

Solvents For Use In The Extractive Distillation Of Piperylene Concentrate, Abdulhadi Sagga

Retrospective Theses and Dissertations

This report describes an evaluation of the effectiveness of different solvents and solvent-organometallic compound mixtures for use in the extractive distillation of a piperylene mixture, consisting of five carbon olefins and diolefins obtained as a byproduct from an ethylene feedstock production plant. The most effective solvent is judged to be the one which gives the best separation of the lowest boiling and highest boiling points of the key components in the mixture. In this study twenty solvents and solvent mixtures were tested. Acetonitrile was found to be the most effective solvent and nitromethane the next most effective.

Part I: The Synthesis Of New Potential Insecticides. Part Ii: New Aromatic Nucleophililic Subsitution Reactions, Fluoroalkoxylation And N,N-Dimethylamination, Cesar Colon

Retrospective Theses and Dissertations

A series of routes are described for the synthesis of new potential insecticides which are symmetrical or asymmetrical similogs of 2,5-Bis (dichloropheny1)-1,3,4-oxadiazole and its precursor diacyl hydrazine. Also two new aromatic nucleophilic substitution reactions are discussed. Activated aryl halides are reacted with fluorinated alkoxide anions. In all cases, substitution of the halogen by a fluoroalkoxy group was observed, and activated aryl halides are reacted with HMPA as an N, N-dimethyl aminating agent. In all cases, substitution of the halogen by a dimethyl amino group was observed. The effect of the activating group and the leaving group is described and a …

Synthesis Of Potential Agrochemicals And Reactions Of Vinamidinium And Azavinamidinium Salts With Organometallic/Borane Reagents And Activated Nitrales, Charles N. Moorefield

Retrospective Theses and Dissertations

This report discusses research which was conducted in two areas: the synthesis of potential agrochemicals and the study of vinamidinium and azavinamidinium salt chemistry. Four classes of compounds were synthesized and characterized in the study of new potential agrochemicals. These compounds include diacylhydrazines, semicarbazides, 2,5-disubstituted-1,3,4-oxadiazoles and bis-2,5-disubstituted-1,3,4-oxadiazoles. The reaction of [3-(dimethylamino)-2-azaprop-2-en-1-ylidene] dimethylammonium chloride (Gold's reagent) with organometallic/borane reagents was examined in efforts to find convenient syntheses for N,N-dimethylamino substituted alkyl and aryl compounds. Additionally, the reaction of 1,5-diazapentadienium chloride (Nair's reagent) with nitrile activated alkanes was examined to find a convenient synthesis of 3-substituted pyridines. Subsequent intramolecular ring closure of …

The Synthesis Of Potential Insecticides: Haloalkoxy Phenyl Diacylydrazines And 1,3,4-Oxadiazoles, Kathleen S. Gibbs-Rein

Retrospective Theses and Dissertations

The syntheses of two classes pf compounds, diacylhydrazines and 2,5-disubstituted 1,3,4-oxadiazoles, intended for subsequent investigation of pesticidal activity are discussed. The experimental conditions and procedures necessary for the preparation of these potential insecticides are also revealed. Finally, spectral data are interpreted and explained, and recommendations for further research are given.

Incremental Analysis Of Programs, Vida Ghodssi

Retrospective Theses and Dissertations

Algorithms used to determine the control and data flow properties of computer programs are generally designed for one-time analysis of an entire new input. Application of such algorithms when the input is only slightly modified results in an inefficient system. In this theses a set of incremental update algorithms are presented for data flow analysis. These algorithms update the solution from a previous analysis to reflect changes in the program. Thus, extensive reanalysis to reflect changes in the program. Thus, extensive reanalysis of programs after each program modification can be avoided. The incremental update algorithms presented for global flow analysis …

An Analytical Model For Evaluating Database Update Schemes, Kathryn C. Kinsley

Retrospective Theses and Dissertations

A methodology is presented for evaluating the performance of database update schemes. The methodology uses the M/Hr/1 queueing model as a basis for this analysis and makes use of the history of how data is used in the database. Parameters have been introduced which can be set based on the characteristics of a specific system. These include update to retrieval ratio, average file size, overhead, block size and the expected number of items in the database. The analysis is specifically directed toward the support of derived data within the relational model. Three support methods are analyzed. These are first examined …

Preparation Of 2,5-Diaryl-1,3,4-Oxadiazoles, Joachim D. Dobe

Retrospective Theses and Dissertations

This report regards the research conducted in the synthesis of 2,5-disubstituted-1,3,4-oxadiazoles as potential insecticides which are closely related to the known insecticide DOWCO 416^R, 2,5-bis(2,4-dichlorophenyl)-1,3,4-oxadiazole. The following compounds were synthesized: 2-(2,4-dichloro-5-nitrophenyl)-5-(2,4-dichlorophenyl)-1,3,4-oxadiazole, (2-(2,4-dichloro-5-nitrophenyl)-5-phenyl-1,3,4-oxadiazole, 2-(2,4-dichloro-5-aminophenyl)-5-aminophenyl)-5-(2,4-dichlorophenyl)-1,3,4-oxadiazole and 2-(2,4-dichloro-5-aminophenyl)-5-phenyl-1,3,4-oxadiazole.

From the commercially available starting material, 2, 4-dichlorobenzoic acid, preparation of the above compounds involved nitration, reduction, esterification, preparation of monoacylhydrazines, preparation of substituted diacylhydrazines and preparation of 2, 5-disubstituted-1, 3, 4-oxadiazoles. All these compounds were characterized via NMR and infrared spectroscopy. In addition, this report includes discussion and recommendations concerning the experimental procedures and conditions for the preparation of these compounds.