• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 174
  • 60
  • 18
  • 17
  • 6
  • 6
  • 6
  • 6
  • 6
  • 6
  • 5
  • 2
  • 2
  • 2
  • 2
  • Tagged with
  • 349
  • 62
  • 40
  • 32
  • 32
  • 27
  • 26
  • 23
  • 22
  • 22
  • 21
  • 20
  • 19
  • 18
  • 18
  • 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.
71

An X-ray investigation of the structure of liquid organic alcohols and acids ...

MacMillan, Donald Patten, January 1938 (has links)
Thesis (Ph. D.)--University of Chicago, 1938. / Lithoprinted. "Private edition, distributed by the University of Chicago libraries, Chicago, Illinois."
72

Part I; Reactions of potassium dihydrogenphosphide and potassium diphenylphosphide with organic carbonyl compounds Part II; Oxidation of primary and secondary alcohols by potassium chlorochromate (VI)

O'Brien, Brian Alan 08 1900 (has links)
No description available.
73

The hydrogenolysis of glycerol to lower alcohols.

Van Ryneveld, Esti. January 2010 (has links)
Much work has been done towards the hydrogenolysis of glycerol to 1,2-PDO and 1,3-PDO using various heterogeneous systems including Rh, Ru, Pt, PtRu, copper systems and Raney Ni in batch systems. However, routes to lower alcohols, such as 1-propanol and ethanol have been less discussed. From an industry point of view, the production of lower alcohols, such as propanol and ethanol, is very interesting. Different ruthenium, palladium and platinum catalysts were employed to study the effect of the support on the catalytic performance in batch mode. These catalysts were evaluated for their production of lower alcohols, especially 1-propanol using concentrated glycerol solutions. Among the other solid acids tested in combination with Ru/C, Amberlyst DT gave the most promising results from a 1-PO point of view, achieving a 34.9 mol% glycerol conversion with a selectivity of 38 mol% selectivity to 1-propanol. Despite the low glycerol conversion (1.3 mol%), Pd/C gave a promising 1-PO selectivity (> 85 mol%). The use of supported Ni catalysts, an inexpensive system, towards the chemical transformation of glycerol to lower alcohols, has appeared less frequently in the literature. The activity of Ni supported catalysts on silica and alumina was studied for the transformation of glycerol to lower alcohols, primarily 1-propanol and ethanol in a fixed bed continuous flow reactor. Several characterisation techniques were performed on the fresh and used catalyst, such as BET, XRD, TPD, TPR, TGA and electron microscopy. The objective was also to continue the development of a more detailed mechanistic understanding of the formation of lower alcohols from glycerol. In an endeavour to understand the process better, the role of proposed intermediates, 1,2-propanediol, 1,3- propanediol, ethylene glycol and ethanol was investigated, as well as the influence of the hydrogen partial pressure. Under the reaction conditions employed, it was clear that the hydrogenolysis of C-C and C-O bonds of glycerol took place to a lesser extent when compared to dehydrogenation and dehydration which are seen as the dominating initial steps. Ethanol was produced in high selectivities with 1,2-propanediol as feed and 1-propanol was the main product obtained when 1,3-propanediol was used as feed. / Thesis (Ph.D.)-University of KwaZulu-Natal, Westville, 2010.
74

Narrowing the molecular weight distribution of linear alcohol ethoxylates

Kuo, Betsy P. 05 1900 (has links)
No description available.
75

The cyclization of phenyl-substituted alcohols and olefins

Roblin, Richard Owen, January 1934 (has links)
Thesis (Ph. D.)--Columbia University, 1934. / Vita. Bibliography: p. 28-30.
76

Influence of sugar and sugar alcohols on mutans streptococci

Wennerholm, Kerstin. January 1994 (has links)
Thesis (doctoral)--Göteborg University, 1994. / Added t.p. with thesis statement inserted. Includes bibliographical references.
77

The cyclization of phenyl-substituted alcohols and olefins,

Roblin, Richard Owen, January 1934 (has links)
Thesis (Ph. D.)--Columbia University, 1934. / Vita. Bibliography: p. 28-30.
78

Influence of sugar and sugar alcohols on mutans streptococci

Wennerholm, Kerstin. January 1994 (has links)
Thesis (doctoral)--Göteborg University, 1994. / Added t.p. with thesis statement inserted. Includes bibliographical references.
79

Alcohols conversion over transition metal based catalyts

Ndebele, Mthobisi Sbonelo January 2018 (has links)
Submitted in fulfillment of the requirements for the Master of Engineering Degree, Durban University of Technology, Durban, South Africa, 2018. / Ethanol and butanol obtainable through fermentation of lignocellulose biomass have become promising alternative feedstock for production of fuels as they are biodegradable and sustainably regenerated via the photosynthesis cycle. The properties of hydrocarbons produced through alcohol conversion closely resemble those of gasoline. Catalytic systems are reported to play a vital role during alcohol conversion to hydrocarbons. In this study ethanol and butanol were used as a feedstock for production of hydrocarbons over Fe, Zn and Ni catalyst systems supported on zeolite ZSM-5 (Zeolite Socony Mobil-5) and activated carbon (AC). X- Ray Diffraction (XRD), Scanning Electron Microscope (SEM) coupled with Energy- dispersive X-ray spectroscopy (EDS) and Brunauer, Emmet, and Teller (BET) analyses were employed for catalyst characterization. XRD patterns confirmed the success of metal doping on ZSM-5 and activated carbon supports. Major peaks at 7.96° and 23.97° corresponding to ZSM-5 crystals were observed in ZSM-5, and AC was found to be amorphous. Impregnation with metals reduced the crystallinity of ZSM-5 supported catalysts. Whereas SEM analysis showed that catalysts supported on ZSM-5 exhibited irregular shapes and catalyst supported on activated carbon exhibited disordered structures. The BET analyses confirmed that the surface areas of promoted catalysts decreased after metal doping. Evaluation of the catalysts were carried out in a ½ inch stainless steel reactor at 400 °C and atmospheric pressure with a weight hourly space velocity (WHSV) of 2.5 h-1 (g feed)/ (g catalyst). The ZSM-5 support performed better than activated carbon support. More than 90% conversion was achieved over catalysts supported on ZSM-5. Production of hydrocarbons over catalysts supported on activated carbon were as a result of the active component. Conversion of feedstock was observed to produce more benzene, toluene and xylene (BTX) compounds with an increase in butanol content. 100% conversion was achieved with pure butanol and not more than 99.86% conversion was achieved with pure ethanol. Catalyst systems supported on HZSM-5 and activated carbon were successfully synthesised. Ethanol, butanol and ethanol-butanol mixtures were successfully converted to liquid hydrocarbons and the conversion was greater than 90%. On the promoted catalysts, production of BTX were suppressed and various metals were observed to perform differently. / M
80

Stereocontrol with phosphine oxides

Hutton, Gordon Eric January 1994 (has links)
No description available.

Page generated in 0.0253 seconds