8,332 research outputs found

    Burton Optical Company (Cases A & B)

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    Thesis (M.B.A.)--Boston Universit

    Cross-Selectivity in the Catalytic Ketonization of Carboxylic Acids

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    A mixture of acetic and 2-methylpropanoic (isobutyric) acids representing non-branched and branched acids, respectively, was catalytically converted to a mixture of ketones in a set of statistically designed experiments (DOE). The selectivity toward the cross-ketonization product was analyzed depending on (a) temperature within 300–450 °C range, (b) molar fraction of each acid in the mixture, from 10% to 90%, and (c) liquid hourly space velocity (LHSV) within 2–12 h−1, and compared against the selectivity toward two symmetrical ketones. Six metal oxide catalysts were tested and ranked on their ability to yield the cross-product as opposed to the self-condensation product. The catalysts were based on either the anatase form of titania or monoclinic form of zirconia and treated with either KOH or K2HPO4. The titania catalyst treated by KOH outperformed all other catalysts by providing the cross-selectivity above the statistically expected binomial distribution. The criterion for having a high cross-selectivity in the decarboxylative ketonization is formulated mathematically as the separation of roles of two acids, one being a more active enolic component, and the other being the preferred carbonyl component. According to the suggested criterion, the less branched acetic acid reacts as both the preferred carbonyl and enolic component with untreated catalysts. Therefore, untreated catalysts promote selective formation of the symmetrical ketone, acetone, thereby decreasing the selectivity to the cross-ketone. After alkaline treatment, both the anatase form of titania and monoclinic form of zirconia increase the isobutyric acid participation as the carbonyl component. Acetic acid remains as the preferred enolic component with all treated catalysts, thus increasing the selectivity toward the cross-product in the ketonization of a mixture of carboxylic acids. The condition for achieving a high cross-selectivity by polarizing roles of the two reactants can be extended to other types of cross-condensations

    White Counselor Trainees\u27 Racial Identity and Working Alliance Perceptions

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    Racial identity has been theorized to significantly affect cross-racial counseling relationships (Helms, 1984, 1995). This study examined the direct impact of White racial identity of 124 counselor trainees on working alliance formation in a same-racial and cross-racial vicarious counseling analogue. Regardless of the race of the client, disintegration and reintegration attitudes negatively affected working alliance ratings, and pseudoindependent and autonomy attitudes positively affected working alliance ratings. Implications for counseling, supervision, training, and research are discussed

    White Counselor Trainees\u27 Racial Identity and Working Alliance Perceptions

    Get PDF
    Racial identity has been theorized to significantly affect cross-racial counseling relationships (Helms, 1984, 1995). This study examined the direct impact of White racial identity of 124 counselor trainees on working alliance formation in a same-racial and cross-racial vicarious counseling analogue. Regardless of the race of the client, disintegration and reintegration attitudes negatively affected working alliance ratings, and pseudoindependent and autonomy attitudes positively affected working alliance ratings. Implications for counseling, supervision, training, and research are discussed
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