• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 112
  • 104
  • 17
  • 12
  • 10
  • 7
  • 7
  • 6
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 321
  • 45
  • 38
  • 32
  • 30
  • 30
  • 28
  • 28
  • 28
  • 26
  • 25
  • 23
  • 22
  • 21
  • 20
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Reactions of potassium ethyl xanthate in aqueous solution

Tipman, Norman Robert January 1970 (has links)
The reactions of potassium ethyl xanthate (KEtX) and its oxidation product diethyl dixanthogen (EtX)₂ were studied in neutral and mildly alkaline aqueous solution. Dissolved oxygen-was shown to be ineffective in oxidizing KEtX in homogeneous systems (solution), but (EtX)₂ was produced electrochemically at a platinum electrode by application of a small anodic overpotential. A slow hydrolysis reaction was proposed for the alkaline decomposition of aqueous ethyl xanthate in which carbon disulfide and ethyl alcohol were the decomposition products. The first order rate constant k₁ = 7.6 ± 1.0 x 10⁻⁴ hr⁻¹ (22°C) was independent of pH in the region pH 7 to 11. Low concentrations of (EtX)₂ (10⁻⁵ to 10⁻⁷ moles liter⁻¹) were determined by a new method based on extraction of the aqueous (EtX)₂ by hexane followed by ultraviolet spectrophotometric determination of the (EtX)₂ in the hexane extract. A sensitive technique for measuring saturation of (EtX)₂ in water using light scattering photometry; was also developed. The solubility of (EtX)₂ in water was found to be 1.27 x 10⁻⁵ moles/liter at 22°C from pH 2 to 8.5. At pH > 8.5, aqueous (EtX)₂ was shown to react with hydroxyl ion by a bimolecular displacement (SN[subscript omitted]2) mechanism which resulted in the formation of one mole of ethyl xanthate and one mole of an intermediate ethyl xanthate sulfenic acid. Decomposition of the intermediate compound resulted in carbon disulfide and other reaction products. The second order rate constant (k₂ = 13.5±0.5 liter mole⁻¹min⁻¹ at 22°C) was determined. Rest potential measurements using a platinum electrode in potassium ethyl xanthate-diethyl dixanthogen solutions showed that the Nernst equation for a one electron reaction was obeyed over a wide range of both KEtX and (EtX)₂ concentrations. Dissolved oxygen was found to generate mixed potentials to which no overall reaction could be assigned. It is expected that the rapid oxidation of ethyl xanthate to diethyl dixanthogen observed in mineral systems proceeds by a catalytic oxidation or electrochemical reaction at or near the mineral surface. / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate
22

Prodrugs: pharmacokinetic theory and structural effects on enzyme-catalyzed hydrolysis of ethyl benzoates /

Huang, Mei-Ying, January 1979 (has links)
No description available.
23

Bond rupture of HBr⁸⁰m following nuclear isomeric transition [I.] ; II. Temperature and phase effects in the photolysis of ethyl iodide

Luebbe, Ray Henry, January 1958 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1958. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 136-139).
24

I. The Effect of light on the velocity of saponification of ethyl acetate. The Velocity coefficient of saponification of methyl acetate ... /

Gooch, Wilby T. January 1923 (has links)
Thesis (Ph. D.)--University of Chicago, 1918. / "Private edition, distributed by the University of Chicago libraries." "References": p. 13. Also available on the Internet.
25

Reactions and derivatives of dichloro-ethyl sulfide ...

Helfrich, Oregon Benson, January 1920 (has links)
Thesis (Ph. D.)--Johns Hopkins University, 1920. / Biography.
26

I. The Effect of light on the velocity of saponification of ethyl acetate. The Velocity coefficient of saponification of methyl acetate ... /

Gooch, Wilby T. January 1923 (has links)
Thesis (Ph. D.)--University of Chicago, 1918. / "Private edition, distributed by the University of Chicago libraries." eContent provider-neutral record in process. Description based on print version record. "References": p. 13.
27

The catalytic action of neutral salts : the effect of normal alkali sulphates on alkali acid sulphates in the ketonic splitting of ethyl acetoacetate

Goodhue, Elbridge Alvah. January 1927 (has links) (PDF)
Thesis (M.S.)--University of Missouri, School of Mines and Metallurgy, 1927. / The entire thesis text is included in file. Typescript. Illustrated by author. Title from title screen of thesis/dissertation PDF file (viewed October 21, 2009) Includes bibliographical references.
28

I. The Effect of light on the velocity of saponification of ethyl acetate. The Velocity coefficient of saponification of methyl acetate ... /

Gooch, Wilby T. January 1923 (has links)
Thesis (Ph. D.)--University of Chicago, 1918. / "Private edition, distributed by the University of Chicago libraries." "References": p. 13.
29

Reactions and derivatives of dichloro-ethyl sulfide ...

Helfrich, Oregon Benson, January 1920 (has links)
Thesis (PH. D.)--Johns Hopkins University, 1920. / Biography.
30

Hydrolysis of ethyl acetate salt solutions of trichloroacetic acid

Manning, Eugene Reynolds. January 1927 (has links)
Thesis (Ph. D.)--University of Pennsylvania, 1927.

Page generated in 0.0254 seconds