No description available.

The use of alkali and alkaline earth metals as reducing agents in liquid ammonia solvent for aromatic and conjugated systems has been investigated by chemists at least since the early 1900's, e.g., Lebau and Picon (1). By subsequent additions of a proton source, the system yielded the first successful partial reduction of a monobenzenoid system, as reported by Wooster and Godfrey (2), in 1937. As a result of that success a patent was issued to Wooster for the process (3). Little additional work was reported until Birch and his co-workers picked up the investigation in the early 1940's. It was through his vigorous study and development of this reduction system that Birch's name came to be associated with reductions of organic compounds by alkali metals in liquid ammonia, hence, the Birch reduction. In this thesis the Birch reduction of cinnamic acid is investigated.

There are a number of inherent problems associated with the analysis of polycyclic aromatic compounds (PAC) in airborne particulate matter. The compounds of interest constitute a very small fraction of the total sample, but consist of hundreds of different components. Therefore, analytical techniques with very high resolving power are required. To try to address these problems, methods have been developed and improved to isolate, and subsequently profile, and identify the PAC present in typical airborne particulate samples. Since no single chromatographic technique can provide the desired resolution, a multi-stage clean-up scheme was required prior to analysis. Two methods were investigated in this study. Both methods used a Soxhlet extraction followed by fractionation using an adsorption chromatography step (silica or alumina) and Sephadex LH-20 to isolate the PAC fraction from the other organic constituents. Another problem associated with the analysis of PAC in airborne particulate matter was because of the method of sample collection. It was believed that there were changes in the chemical composition of the particulate and hence the PAC, during sample collection using a Hi-Vol sampler. Artifacts were being formed by reaction of gaseous pollutants with the particulate collected on the filter. An experiment was established to show that the addition of a denuder bundle to a Hi-Vol sampler could reduce this artifact formation during sampling by removing the reactive gases prior to the surface of the filter. The value of the denuder bundle was evaluated by comparison of the PAC from the denuder Hi-Vol with a standard Hi-Vol. Normal-phase HPLC coupled with mass spectrometry was shown to be a good method to compare the PAC in these samples. Some differences between standard and denuder Hi-Vol samples were observed in laboratory experiments, while the results from field sampling were inconclusive. The use of a parallel column gas chromatography-mass spectrometry (GC-MS) (also called third order chromatography) technique was investigated to determine its viability for the identification of the diverse range of PAC present in environmental samples. The PAC . in the NBS urban dust sample (SRM 1649) was analyzed to evaluate the method. To aid in data processing, a semi-automated peak detection routine has been developed. This routine used programs to aid in the data processing by simplifying peak detection and allow calculation of the retention indices of the components. Using the information supplied by the retention indices and the mass spectra, a data base was developed that was applied to a typical airborne particulate sample. / Thesis / Doctor of Philosophy (PhD)

No description available.

No description available.

The biochemical pathway for the anaerobic degradation of gallate, pyrogallol and phloroglucinol by Eubacterium oxidoreducens was investigated. Phloroglucinol reductase was purified 90-fold, from the soluble fraction of cell extract, to electrophoretic homogeneity. The enzyme was an α₂ homodimer with a native M_r of 78,000, did not contain metals or cofactors and was specific for phloroglucinol and NADPH with a K_m of 800 μM and 6.7 μM respectively at pH 6.8. The Km for phloroglucinol decreased with increasing pH. The enzyme catalyzed reaction was reversible and the equilibrium constant was 9.6. Dihydroresorcinol was a competitive inhibitor of the reverse reaction (K_i = 756 μM). Dihydrophloroglucinol produced in cell extract with H₂ as the reductant was identical to the compound produced by sodium borohydride reduction of phloroglucinol as shown by ¹H NMR spectroscopy. The ¹³C NMR spectrum was consistent with the structural assignment of dihydrophloroglucinol. The mechanism of the proposed enzymatically catalyzed reaction is proposed to involve transfer of a hydride equivalent from NADPH to the carbonyl carbon of the phloroglucinol dianion. Mutant strains of E. oxidoreducens that showed no gallate decarboxylase or dihydrophloroglucinol hydrolase activity were isolated after mutagenesis with ethylmethane sulfonate and emichment with ampicillin. The decarboxylase deficient mutants were unable to grow on gallate while pyrogallol and phloroglucinol supported growth. The hydrolase deficient mutants were unable to grow on any aromatic substrates and converted gallate to pyrogallol and dihydrophloroglucinol. The conversion of gallate to non-aromatic intermediates by cell extract of the wild-type stain was dependent on the presence of 1,2,3,5-benzenetetrol for the conversion of pyrogallol to phloroglucinol and on formate for the reduction of phloroglucinol to dihydrophloroglucinol. Transhydroxylase activity involved in the conversion of pyrogallol to phloroglucinol was induced by growth on aromatic substrates. The formate dehydrogenase was located in the soluble fraction of cell extract, and activity was protected from oxygen inactivation by sodium azide. The Km for formate and NADP was 290 μM and 140 μM respectively at pH 7.5. The pH optimum for activity was 7.5 and maximum activity was observed at a temperature of 50°C. / Ph. D.

Thesis (M.S.)---University of North Carolina Wilmington, 2008 / Title from PDF title page (October 20, 2008) Includes bibliographical references (105-110)

The preparation of 2-(3-chloro-l-naphthylmethyl)bromobenzene was achieved by the cross-condensation reaction of 3-chloro-l-naphthylmagnesium bromide and 2-bromobenzyl bromide, as well as by the reaction of this Grignard reagent with 2-bromobenzaldehyde, followed by reduction of the resulting carbinol with lithium aluminum hydride and aluminum chloride. It was found that 2-bromophenyl-1-(3-chloronaphthyl)carbinol thermally decomposed into the corresponding methylene compound and ketone. A study of the thermally induced reaction of the carbinol was made, and the products were quantitatively analyzed by means of gas chromatography. It was concluded that the anomalous products of the reaction of an aryl Grignard reagent with a benzaldehyde were actually p~duced by the thennal disproportionation of the resulting carbinols during the distillation step. The keto-acid, 2-(3-chloro-l-naphthylmethyl)- 2’-carboxybenzophenone was prepared by the inverseaddition of the Grignard reagent of 2-(3-chloro-l-naphthylmethyl)bromobenzene to phthalic anhydride. Cyclization of this keto-acid with an acetic and hydrobromic acid mixture gave 6-chloro-7-(2-carboxyphenyl)benz[a]anthracene. Methyl ester derivatives were prepared from both this acid and the precursor keto-acid. The cyclodehydration of either 2-(3-chloro-l-naphthylmethyl)-2'-carboxybenzophenone or 6-chloro-7-(2-carboxyphenyl)benz[a]anthracene with polyphosphoric acid gave 14-chlorodibenzo[hi,l]chrysen-9-one.· Treatment of this ketone with lithium aluminum hydride and aluminum chloride gave the reduction derivative, 14-chloro-9H-dibenzo[hi,l]chrysene. The unequivocal synthesis of dibenzo[hi,l]- chrysen-9-one was achieved by the dehalogenation of 14-chlorodibenzo[hi,l]chrysen-9-one with 10% palladiumcharcoal catalyst and hydrazine. The dehalogenated product was shown to be identical to the compound produced from the cyclodehydration of 7-(2-carboxyphenyl)benz[a]anthracene. The ketone, 2-(3-chloro-l-naphthylmethyl)benzophenone was prepared by the inverse-addition of the Grignard reagent of 2-(3-chloro-l-naphthylmethyl)- bromobenzene to benzoyl chloride. It was found that a small amount (16%) of 6-chloro-7-phenylbenz[a]-anthracene was formed during the distillation of the precursor ketone. The cyclodehydration of this ketone failed when various standard cyclizing media were employed, and the reason for this is discussed. Cyclization attempts with polyphosphoric acid or alumina gave dibenzo[a,l]pyrene as the only identifiable product. This unusual reaction obviously involves a rearrangement. A study was made and a mechanism for this reaction was postulated which is consistent with the experimental observations. The ketone, 2-(3-cyano-l-naphthylmethyl)benzophenone was prepared by the reaction of the corresponding chloro ketone with cuprous cyanide in N-methylpyrrolidone. 6-Cyano-7-phenylbenz[a]- anthracene was also produced in small quantity in this reaction as a consequence of the presence of the corresponding chloro compound in the ketone prior to reaction. Naphtho[3, 2, l-fg]naphthacen-9-one was prepared by the treatment of 6-cyano-7-phenylbenz[a]anthracene with a hydrobromic and acetic acid mixture at 180°, and also by the treatment of the precursor cyano ketone with polyphosphoric acid. The novel use of polyphosphoric acid in cyano group hydrolysis is discussed. Phenalo[2, 3, 4, 5-defg]naphthacene-4, 8-quinone was prepared by the treatment of 6-cyano-7-(2-carboxyphenyl)benz[a]anthracene with a hydrobromic and acetic acid mixture at 180°. An attempted procedure for the. preparation of this quinone involved the oxidation of 7-(2,6-dimethylphenyl)benz[a]anthracene to the corresponding diacid with aqueous sodium dichromate. Unfortunately this new method of oxidation failed in this case. The partial resolution of 7-(2-carboxyphenyl)-benz[a]anthracene was achieved with the use of brucine. Only one optically active isomer was obtained, and this was racemized by treatment with boiling ethanol. An empirical rule used to quantitatively determine the resistance of optically active biphenyls to racemization was applied to this acid, and the experimental observations were supported. During the course of this investigation, sixteen new compounds were prepared and were all properly characterized, except 6-cyano-7-(2-carboxyphenyl)- benz[a]anthracene, which did not give acceptable analytical data. The reason for this is discussed. Infrared and ultraviolet spectra of all new compounds were recorded. Infrared spectral observations were made which gave further support to the assigned structures of the isomeric compounds naphtho[3,2,l-fg]- naphthacen-9-one and dibenzo[hi,l]chrysen-9-one. / Doctor of Philosophy

The solubilities of benzene, naphthalene and anthracene were measured in five binary solvent systems. These systems consised of water and one of the following water miscible organic solvents: acetone, acetonitrile, methanol, ethanol, and isopropanol. The measurements were made at intervals of 0.1 volume fractions of the organic cosolvent. Solubility data were also collected for the above solutes in mixed cosolvents. solvent systems containing three In addition, the solubilities of and six five other aromatic solutes were measured in the binary solvent systems of methanol/water and acetone/water. The data was used to test the log-linear solubility model of Yalkowsky (1981). The model predicts a linear relationship between the solubility of a solute in a binary solvent system (S(m)) and the volume fraction of cosolvent present (f(c)) log S(m) = σf(c) + log S(w) Where S(w) is the solubility of the solute in water and σ is the proportionality constant and slope of the curve. The model is easily extended to multiple mixed solvents by combining the σ values from the binary solvent systems. log (S(m)/S(w)) = Σ₁ (σ₁£₁) A method was developed to estimate σ in a given binary solvent system from the octanol-water partition coefficient of the solute. Combining this method with the generalized solubility equation of Yalkowsky to estimate S(w), allows a priori estimates of solubility in mixed solvents. Maximum deviations in the binary solvent systems studied were related to maxima in excess density. In the alcoholic binary solvent systems the minima were related to minima in the heats of mixing of the two cosolvents. The herbicide atrazine deviated dramatically from the model. The system was examined for possible changes in the crystal structure of atrazine. It was found that some crystal modification occured in the presence of mixed solvents. The rate of the change appears to be dependant on the concentration of the cosolvent. A change or modification in the crystal violates one of the basic assumptions of the log-linear model. The assumption is that the crystal contributes equally to the solubility behavior irrespective of the solvent system. It was determined that atrazine undergoes a polymorphic transition in the systems studied. It is postulated that this polymorphism is responsible for the anomolous solubility behavior observed for atrazine.

The luminescence properties of Van Der Waals' dimers and clusters of pyrene and diazapyrene have been investigated. Excimers, dimeric species which are associative in an excited electronic state and dissociative in their ground state, have long been established and play an important role in many areas of photochemistry. My work here focuses on the luminescence and absorption properties of ground state dimers/aggregates, which are less understood, and allows further characterization of the ground state and excited state association of these aromatic molecules.