A study has been made of the pyrolysis of 1,5-hexadiene (diallyl) and of the reactions of the allyl radicals thus produced with 1-butene. The pyrolysis of 1,5-hexadiene was found to be first order and appears to proceed mainly by free radical reactions in the temperature range 460 - 520° C. However, molecular rearrangement in the formation of cyclohexene and benzene are possible. The over-all activation energy for the process was found to be 31.3 kcal/mole for an A factor of 10⁸˙⁵ min¯¹. The main products among the gaseous compounds were methane, ethane, ethylene, propylene, and 1-butene. The main liquid products were cyclopentene, cyclopentadiene, 1-hexene and benzene. Evidence was obtained for hydrogen abstraction by allyl and addition of the allyl radical to olefinic double bonds. Activation energies for the formation of methane, ethane, propane, ethylene, propylene and 1-butene were determined. Addition of approximately 5 % by volume of 1,5-hexadiene was found to increase the rate of the pyrolysis of 1-butene about 6-7 times at 506° C. The formation of C₅-cyclic products and methane was found to be proportional to (diallyl)½ . This provides kinetic evidence that allyl radicals are involved directly in the formation of these products in the sensitized decomposition and also that the primary step in the pyrolysis of diallyl involves the formation of two allyl radicals. Mechanism for the pyrolysis of diallyl and for the reactions of allyl with 1-butene are discussed. A brief study has also been made of the pyrolysis of 1-butene in the presence of acetaldehyde. The thermal decomposition of 1-butene sensitized by addition of 25% by volume of acetaldehyde was carried out at 477° C. The decomposition of acetaldehyde was found to be inhibited by the presence of 1-butene by a factor of more than two. 1-butene, which practically does not decompose at the above temperature by itself, decomposes appreciably in the presence of acetaldehyde. / Science, Faculty of / Chemistry, Department of / Graduate

Work was undertaken to examine the antibacterial mechanism of allyl isothiocyanate (AITC), as well as explore the hydrolysis of sinigrin by bacteria and sinigrin metabolism in Escherichia coli O157:H7. Glucosinolates are found in cruciferous plants and react with the plant enzyme myrosinase to form antimicrobial compounds called isothiocyanates (ITCs). The mechanism of bactericidal action of ITCs is not well understood. Inhibition experiments against 12 bacteria including foodborne pathogens and starter cultures indicated that AITC exhibited a minimum inhibitory concentration (MIC) profile most similar to antibiotics ciprofloxacin and polymyxin B. Similarities in mechanisms of action between groups were identified. The sinigrin degradation capacity of a range of bacteria was examined. The effect of glucose in combination with other sugars on the sinigrin degradation capacity of E. coli O157:H7 was assessed. No statistically significant differences in sinigrin utilisation were observed. Results indicated that the metabolism of sinigrin was simultaneous with glucose consumption. / February 2016

The reactions of the ethyl radical with a series of allyl compounds were examined experimentally in the gas phase, and the results were seen to conform to a general mechanism. Specifically, the ethyl radical can abstract a hydrogen atom from the allyl compound, or add to the olefinic linkage of the allyl compound. Dismutation reactions of the product radicals formed in the addition or abstraction reactions were also observed in this study. The metathesis reactions of some allyl compounds were too slow to be measured unless the functional group was deuterated. When this was done in the case of allyl alcohol and allyl formate, primary isotope effects in metathesis could be measured, and were in good agreement with the values predicted on the basis of zero point energy differences. The activation energies of the dismutation reactions of the adduct radicals ranged from 15 to 27 Kcal/mole and were found to depend on the estimated enthalpies of this reaction. In certain cases, a choice between two different reaction routes of the dismutation reaction could be made by comparing the activation energy with the estimated enthalpy change. The dismutation reaction offers a convenient method for the generation of free radicals at low temperatures. In this way, the allyl and ethoxy radicals were generated, and their disproportionation-combination ratios with the ethyl radical were measured. The kinetics of interaction of the ethyl radical with an allyl compound in the gas phase can be compared with the polymerization of that monomer in the liquid phase. Specifically the ratio of the addition rate constant to the metathesis rate constant in the gas phase can be related to the degree of polymerization and a linear relationship between these quantities was found in this study. / Science, Faculty of / Chemistry, Department of / Graduate

Thesis advisor: James P. Morken / Internal allyl electrophiles were successfully implemented in a catalytic cross-coupling to allylB(pin) with high regiocontrol to afford multisubstituted 1,5-dienes bearing chemically differentiated olefins. Construction of alkenyl compounds with all carbon quaternary centers and high enantiomeric excess can be achieved in one step without the use of enantiomerically enriched chiral ligands. / Thesis (MS) — Boston College, 2015. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.

No description available.

No description available.

No description available.

No description available.

No description available.

No description available.