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  Partner: UNT Libraries
 Degree Discipline: Chemistry
 Collection: UNT Theses and Dissertations
Mechanisms of Methoxide Ion Substitution and Acid- Catalyzed Z/E Isomerization of N-Methoxyimines

Mechanisms of Methoxide Ion Substitution and Acid- Catalyzed Z/E Isomerization of N-Methoxyimines

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Date: December 2001
Creator: Dolliver, Debra D.
Description: The second order rate constants for nucleophilic substitution by methoxide of (Z)- and (E)-O-methylbenzohydroximoyl fluorides [C6H4C(F)=NOCH3] with various substituents on the phenyl ring [p-OCH3 (1h, 2h), p-CH3 (1g, 2g), p-Cl (1f, 2f), p-H (1e, 2e), (3,5)-bis-CF3 (1i, 2i)] in 90:10 DMSO:MeOH have been measured. A Hammett plot of these rate constants vs σ values gave positive ρ values of 2.95 (Z isomer) and 3.29 (E isomer). Comparison of these rates with methoxide substitution rates for Omethylbenzohydroximoyl bromide [C6H4C(Br)=NOCH3] and Omethylbenzohydroximoyl chloride [C6H4C(Cl)=NOCH3] reveal an element effect for the Z isomers of Br:Cl:F(1e) = 2.21:1.00:79.7 and for the E isomers of Cl:F(2e) = 1.00:18.3. With the p-OCH3-imidoyl halides the following element effects are found: Br:Cl:F(1h) = 2.78:1.00:73.1 for the Z isomer and Br:Cl:F(2h) = 1.97:1.00:12.1 for the E isomer. Measurement of activation parameters revealed ∆S≠ = -17 eu for 1e and ∆S≠ = -9.9 eu for 2e. Ab initio calculations (HF/6-31+G*, MP2/6-31+G*//HF/6-31+G*, B3LYP/6- 31+G*//HF/6-31+G*, HF-SCIPCM/6-31+G*//HF/6-31+G*) were performed to define the reaction surface. These calculations demonstrate a relatively large barrier for nucleophilic attack in relation to halogen loss and support the experimental findings that this reaction proceeds by an addition-elimination mechanism (AN# + DN). The imidoyl fluorides have been used to synthesize ...
Contributing Partner: UNT Libraries
The Mercury Photosensitized Reactions of some Hydrocarbons

The Mercury Photosensitized Reactions of some Hydrocarbons

Date: 1946
Creator: Dickinson, Ermintrude
Description: The problem was to study the behavior of several hydrocarbons when they were subjected to ultraviolet light of 2536 Å in the presence of mercury vapor.
Contributing Partner: UNT Libraries
The Mercury-Sensitized Photo-Reactions of 2,3-Dimethyl Butane

The Mercury-Sensitized Photo-Reactions of 2,3-Dimethyl Butane

Date: 1947
Creator: Sutton, Cecil C.
Description: The work encompassed by this thesis is partially a reproduction of the results obtained by John A. Marcia in his work on the photo-chemical reactions of branched hydrocarbons. The previous work done on this particular problem was rendered partially valueless because of the loss of the liquid hydrocarbon product when a fractionation column at the Texas Company Laboratory, Beacon, New York, broke during the fractionation run.
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The Mercury-Sensitized Photo-Reactions of a Mixture of Propane and Isobutane

The Mercury-Sensitized Photo-Reactions of a Mixture of Propane and Isobutane

Date: 1947
Creator: Vaughan, George
Description: It was decided to determine whether or not 2,2,3-trimethylbutane could be formed by the photochemical reaction of isobutane and propane in the presence of mercury vapor energized by ultraviolet radiation from a mercury vapor lamp.
Contributing Partner: UNT Libraries
The Mercury-Sensitized Photo-Reactions of Isobutane

The Mercury-Sensitized Photo-Reactions of Isobutane

Date: 1943
Creator: Stallings, James Cameron
Description: A study of the mercury-sensitized photo-reactions of isobutane.
Contributing Partner: UNT Libraries
The Mercury-Sensitized Photochemical Reactions of Cyclohexane

The Mercury-Sensitized Photochemical Reactions of Cyclohexane

Date: 1950
Creator: Layne, Douglas Kenneth
Description: This study is about the mercury sensitized photochemical reactions of cyclohexane.
Contributing Partner: UNT Libraries
Mercury-Sensitized Photochemical Reactions of Isopropyl Alcohol

Mercury-Sensitized Photochemical Reactions of Isopropyl Alcohol

Date: August 1955
Creator: Brown, Robert Wade
Description: This thesis discusses the mercury-sensitized photochemical reactions of isopropyl alcohol.
Contributing Partner: UNT Libraries
Mercury-Sensitized Photochemical Reactions of Isopropyl Alcohol

Mercury-Sensitized Photochemical Reactions of Isopropyl Alcohol

Date: May 1959
Creator: Armstrong, Andrew Thurman
Description: This thesis describes the reactions of mercury-sensitized isopropyl alcohol when bombarded with 2537 Angstrom radiation.
Contributing Partner: UNT Libraries
Mercury-sensitized Photochemical Reactions of Isopropyl Alcohol

Mercury-sensitized Photochemical Reactions of Isopropyl Alcohol

Date: 1956
Creator: Brady, William Thomas
Description: The nature and scope of this problem is to determine from the irradiation of isopropyl alcohol with 2537 A, the behavior and mechanism of the reaction, since it is known that a reaction does occur.
Contributing Partner: UNT Libraries
The Mercury-Sensitized Photochemical Reactions of Isopropyl Benzene and Methylcyclohexane

The Mercury-Sensitized Photochemical Reactions of Isopropyl Benzene and Methylcyclohexane

Date: 1951
Creator: Holland, Walter
Description: This thesis describes the theoretical results of mercury-sensitized photochemical reactions of isopropyl benzene and methylcyclohexane. The reactions are carried out and the results are analyzed.
Contributing Partner: UNT Libraries