• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 20
  • Tagged with
  • 26
  • 26
  • 26
  • 5
  • 4
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 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.

Heat-transfer coefficients for film condensation of steam on an inclined cylinder

Garrett, Todd January 1960 (has links)
This thesis discusses an investigation of film condensation of steam on the outside surface of an inclined cylinder. The objectives of the investigation were (1) to obtain heat-transfer coefficients for steam condensing on an inclined cylinder, (2) to determine the effect of the angle of inclination of the cylinder on the condensing coefficient, and (3) to verify values of the coefficient obtained from an accompanying theoretical development. Experiments were conducted for steam condensing on a 12.45 in. length of the outside surface of a 3/4 in. diameter by 0.065 in. thick wall, water-cooled, copper tube. Condensing coefficients were obtained for inclinations to the horizontal from 0° to 90° at 15° intervals. It was found that these coefficients decreased in value as the angle of inclination increased from 0° to 90°. At the same time good agreement was obtained between the measured and theoretical coefficients. No single equation could be found which would correlate the results for all the inclinations tested, but general equations were obtained which apply for each of two zones. One zone included inclinations from 0° to 30°, the other inclinations from 45° to 90°. The zone from 30° to 45° requires more investigation before it can be satisfactorily correlated. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate

Studies of the condensation products of ethyl 3-phenyl-2,3-dioxopropanoate with active methylene compounds

Moore, Frank Archer. January 1952 (has links)
Call number: LD2668 .T4 1952 M61 / Master of Science

Further studies on phenolic hexamethylenetetramine compounds

Harvey, Mortimer Thomas, January 1920 (has links)
Thesis (Ph. D.)--Columbia University, 1920. / Vita.

Studies on the phenol formaldehyde condensation

Edell, Gerard Munz, January 1932 (has links)
Thesis (Ph. D.)--Columbia University, 1932. / Vita. Bibliography: p. 31.

The Stobbe condensation the use of sodium hydride as the condensing agent /

Daub, Guido H., January 1949 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1949. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Malononitriles and cyanoacetamides containing isoxazoles and isoxazolines

Moores, Lee C. 13 August 2011 (has links)
Isoxazoles and isoxazolines have been shown in the literature to be an important scaffold for pharmaceuticals and insecticides, as well as a source of synthetic versatility important to many syntheses. As a substitute for other aromatic rings, isoxazoles are known to change the efficacy of a given compound. Isoxazolines can be used as a precursor to many other functional moieties that may be effected during earlier synthetic steps. There are many routes to the heterocyclic moiety, allowing for their insertion in a wide range of molecules. Our group has previously reported a condensation of arylaldehydes with hydroxylamine to first make an aryloxime which can, after generating the nitrile oxide, then cyclize with an alkene or alkyne in situ and create the isoxazoline or isoxazole, respectively. The Knoevenagel Condensation reaction is identified as the addition of an activated methylene complex, malononitrile or cyanoacetamide, with a carbonyl followed by dehydration.. Our group has previously reported a facile, one-pot reductive alkylation of benzyl malononitriles. These compounds have been noted as having many insecticidal uses, as well as being potent pharmacophores. The scope of this project is to further explore and optimize the condensation of aryl aldehydes and methylene complexes. The condensed and reduced methylene complex will then be alkylated to join the heterocyclic moiety to reach the final disubstituted methylene product. A second approach will also be explored in which the monosubstituted malononitrile will first be alkylated with allyl or propargyl bromide, which can then undergo a 1,3-dipolar cycloaddition with a nitrile oxide. The library of compounds generated will be sent to collaborators to test the biological activity of the molecules. / Introduction and background literature -- Reactions of methylene complexes -- Synthesis of disubstituted methylene complexes. / Department of Chemistry

Chemistry of quinoline-2-carbaldehyde derivatives with malononitrile and formation of indolizines

Murali, Dheeptha 13 August 2011 (has links)
The quinoline-5,8-diones are an important class of compounds with a wide spectrum of biological activites such as antibacterial, antiasthmatic, antifungal, antitumour and antiparasitic agents. Over the past three decades many variously substituted derivatives of quinoline-5,8-diones have been synthesized and reported. The majority of them dealt with the chemistry of C-6 and/or C-7 substituted quinolinediones and were related to Lavendamycin. Our lab has developed several procedures for the condensation (Knoevenagel) and reduction of aldehydes and ketones with malononitrile. When this reductive alkylation procedure was attempted with quinoline-2-carboxaldehyde, a crude product was observed by NMR spectroscopy. This product rearranged upon attempted purification via recrystallization or column chromatography. The nucleophilic attack of the quinoline N on the C of the nitrile followed by a proton transfer and a tautomerization resulted in the creation of indolizine. We will study the reductive alkylation of a series of quinoline-5,8-diones with carboxaldehydes at the C-2 position with malononitrile. This reaction is carried out in 95% ethanol with no catalysts present. This reaction mixture is then diluted with additional 95% ethanol and then cooled in an ice/water bath before the addition of sodium borohydride (NaBH4) to afford the desired monosubstituted malononitrile. We have also carried out the reactions with a range of other substituted quinoline compounds. In these cases the indolizines were not observed. It is assumed that the indolizine product does not form due to the presence of substituents on the C-8 position. Additional studies will focus on unsubstituted C-8 quinoline rings to prepare other novel indolizines. Otherwise, various reactions are performed to force the formation of indolizine. / Introduction/background -- Preparation of quinoline derivatives and their respective carboxaldehydes -- Preparation of monosubstituted malononitriles and indolizines. / Department of Chemistry

Condensations by means of halogen acids ...

Pantsios, Athan Anastasov, January 1941 (has links)
Thesis (Ph. D.)--University of Chicago, 1938. / Reproduced from type-written copy. "Private edition, distributed by the University of Chicago libraries, Chicago, Illinois." eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Condensation of unsaturated hydrocarbons with phenols--mechanism for the condensation of the ethylenic bond with phenols ...

Natelson, Samuel. January 1931 (has links)
Thesis (Ph. D.)--New York University, 1931. / eContent provider-neutral record in process. Description based on print version record. Bibliography: p. 13.

2-(2ʹ hydroxyethyl)-3-picoline and its condensation with 2-methyl-5-bromomethyl-6-aminopyrimidine hydrobromide an analog of thiamine ...

Finkelstein, Jacob, January 1939 (has links)
Thesis (Ph. D.)--Columbia University, 1939. / Vita. Bibliography: p. [22-23].

Page generated in 0.5575 seconds