Haky, Jerome E.

The effect of the hydrophobicity of organic compounds on their micelle-water partition coefficients was investigated. The micelle-water partition coefficients were obtained by UV/VIS spectroscopy and correlated with their octanol-water partition coefficients. The octanol-water partition coefficient of an organic compound is a measure of its hydrophobicity. Hydrophobicity alone did not influence the micelle-water partition coefficients. Further research is required to substantiate present findings and obtain additional related information.

New organometallic containing materials were synthesized by the reaction of Group IVB metallocene dichlorides of the form Cp2MCl2 where M = Ti, Ar, and Hf with Hematoporphyrin IX using the interfacial condensation polymerization technique. The structural characterization was accomplished using infrared and mass spectroscopy and elemental analysis. The results obtained from these techniques showed the presence of the metal ester and ether bonding as evidence that the reaction occurred. The product derived from titanocene dichloride, 12-A, exhibited growth inhibition characteristics towards the Candid albicans and Staphylococcus aureus microorganisms. From the preliminary metal adsorption studies it was shown that this product also bound nickel ions.

The performance of several alkyl-bonded alumina-based stationary phases was evaluated by comparing the separation of synthetic octapeptide and polypeptide mixtures and tryptic digests of larger proteins. These phases were of differing pore diameter, alkyl chain length modification and particle shape and size. The separations were compared to standard silica phases. The narrow pore octadecyl bonded alumina phase outperformed the other alumina and silica phases in terms of separation efficiency and mobile phase resistance. Superior performance is attributed to the enhanced solute mass transfer properties and the unique morphology of the microplatelet alumina particles. The mechanism of separation gradually changes with increasing size of the peptide.

Alumina-based stationary phases are evaluated for the separations of proteins and peptides by reversed phase high performance liquid chromatography. Separations are compared to those obtained on a widely-used octadecylsilane (ODS) phase. The separations of peptides on alumina-based stationary phases are found to be superior while separations of proteins are inferior as compared to those found on ODS phase. The superior performance of peptide separations on alumina-based columns is attributed to lower pore size and uniquely-shaped particles of the alumina. The retentions of peptides and proteins on both alumina and silica-based stationary phases are shown to be governed by hydrophobic interaction mechanisms.

The chromatographic properties of Octadecylsilica (ODS), Octadecylalumina (ODA), Polybutadiene coated alumina (PBD), Styrene-divinylbenzene copolymer (ACT-1) were investigated to evaluate Octanol-Water partition coefficient, log P, using a correlation method of High Performance Liquid Chromatographic (HPLC) capacity factor, k', and literature partition coefficient values. This study revealed the superior chromatographic characteristics of ODA material and its potential for the evaluation of log P values of organic compounds, in particular, bases. The log P(HPLC) values evaluated using the log k'-log P regression equation obtained from a set of standards on ODA appeared to be accurate. These values matched with the theoretical calculations supporting the accuracy of the HPLC method.

In this study we correlate academic and non-academic descriptors with Organic Chemistry final grades for students enrolled at a Florida public university. Using multiple regression analysis, the following predictors are analyzed for a sample population of 904 students: age, gender, ethnicity, academic classification, SAT scores, major, overall grade point average (GPA), semesters lapsed between courses, institution where General Chemistry was taken, prerequisite grades, and number of math and science courses taken with their respective grades. Results indicate strong correlations exist between final grade in Organic Chemistry, GPA and General Chemistry final grade. Additionally, Organic Chemistry final grades correlate with academic course load and the type of institution where General Chemistry was studied. We believe these results can be employing as a tool for advising students in planning their academic programs.

A computer program was developed to simulate and optimize the chemical pretreatment of seawater prior to desalination by reverse osmosis. The model was created using LabViewRTM programming language. The automation of the process was achieved using a PID (proportional, integrative, derivative) controller. The effects of a variety of operating conditions were modeled to optimize the chemical pretreatment. We focused on three parameters: hardness removal, iron removal and control of biogrowth. The validity of the model was verified with laboratory scale experiments. In the range of the model, the predicted values differ by a maximum of 11% from experimental results.

Three aluminum organophosphonate compounds; aluminum phenylphosphonate, aluminum octylphosphonate, and aluminum octadecylphosphonate, have been synthesized by refluxing aluminum nitrate with an excess of the appropriate organophosphonic acid in aqueous, methanol, or butanol solvents respectively. Each of these compounds was found to have pillared layered structures and ligand to metal ratios of 2:1. Additionally, these compounds were shown to exhibit cation exchange properties. In contrast to that observed for conventional cation-exchange resins, the exchange capacities of these compounds are larger for small cations, such as Li+ and Na+, than for larger ions such as Na+ and K+. The results indicate a size selectivity which is directly related to the accessibility of these ions to the exchangeable sites of these compounds.

Chromatographic stability studies of an alumina-based reversed phase, ODA, stationary phase were performed. These studies involved monitoring the chromatographic performance of columns packed with the ODA phase after separate, continuous treatment with aqueous solutions of trifluoroacetic acid and sodium hydroxide over a period of several weeks. Chromatographic performance of the ODA columns undergoing treatment with these mobile phases was evaluated by comparing changes in chromatographic capacity factors, resolutions, plate numbers, and peak asymmetries of a test mixture consisting of uracil, phenol, aniline, methyl benzoate, m-toluidine, N,N-dimethylaniline, and toluene. The results indicate that the alumina-based ODA phase is stable under acidic conditions (pH 2--3) and exceptionally stable to chemical degradation under alkaline conditions (pH ∼ 11).

We have synthesized intermediates towards the preparation of a polyphosphonate ester containing L-dopa for the potential treatment of Parkinson's disease. A synthetic strategy was devised to be more reproducible than the original strategy. We discovered some very interesting chemistry of one of the intermediates produced from this new scheme. We synthesized L-N-(butyloxycarbonyl)-3-(3-hydroxy-ethyl-4-(benzyloxy)-phenyl)alanine benzylester, a compound containing a secondary alcohol moiety that had a unique set of characteristics. Upon reduction of the N-(tert-butyloxycarbonyl)-3-(3-acetyl-4-benzyloxyphenyl)-L-alanine benzylester, which contained a ketone moiety, to produce the secondary alcohol, we discovered that the materials that were formed included a pair of diastereomers of the secondary alcohol, each diastereomer also exhibiting two individually stable conformational isomers. We believe that the conformational isomers were generated by rotation of the C-N bond of the BOC carbamate, and were so stable that they could be separated by HPLC and NMR techniques. Energy optimization studies and molecular modeling techniques were performed using HyperChem, and rotational barrier energy values were calculated for the different conformational isomers for each of the diastereomers. HPLC and NMR techniques were also used to obtain information about these materials. Using the calculated data from these studies, and analyzing the HPLC chromatograms and NMR spectra we were able to fully determine the assignments for the diastereomers and the individual conformational isomers. We discovered that the SS form was synthesized preferentially over the SR form and that in both cases the E conformation was energetically more stable than the Z form. Octanol/water partition coefficient values (Log P0ct) were also determined and compared to L-dopa and dopamine. We concluded that the values for the dimeric compound that we synthesized and many of its potential products of degradation were significantly higher than that for both L-dopa and dopamine. This may be an indication that this material has a higher degree of lipophilicity than L-dopa itself, having more potential to cross the blood brain barrier. We believe that these intermediate materials serve as good indication of how a polyphosphonate ester containing L-dopa would compare as a potential drug for Parkinson's disease.