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  • 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.
1

The synthesis of some secondary amyl and hexyl homologues of dinitro ortho and paracresols

Moffatt, John Gilbert January 1953 (has links)
Eight new dinitro-sec.-amyl and hexylphenols of unequivocal structure were synthesized and characterized by their piperidine, morpholine and cyclohexylamine salts. The synthetic route followed involves the Fries rearrangement, of phenyl acetate and phenyl propionate to give the easily separated isomers o- and p-hydroxyacetophenone and o- and p-hydrcocypropiophenone. These compounds were then methylated to give the corresponding methoxyacetophenones and methoxypropiophenones. The methylated aryl-alkyl ketones were condensed through a Grignard reaction with various alkyl bromides to give tertiary alcohols which were dehydrated by the Dean and Stark method to the corresponding olefins and then hydrogenated to alkylanisoles. Demethylation was effected through the use of pyridine hydrobrondde for the p-alkylphenols, or 47% hydriodic acid and phenol for the o-alkylphenols. The alkyl phenols were then nitrated with fuming nitric acid in glacial acetic acid at -15⁰C., and the resulting dinitro-alkylphenols characterized as amine salts. The phenols prepared were: 3-(o- and p-hydroxyphenyl)-pentane, 2-(o- and p-hydroxyphenyl)-hexane, 2-(o- and p-hydroxyphenyl)-3-methylpentane, 2-(o- and p-hydroxyphenyl)-4-methylpentane. Of these, only 2-(p-methoxyphenyl)-3-mathylpentane has been reported prepared by an unequivocal synthesis. All other phenols, their intermediates and derivatives, and their dinitro derivatives, are previously unreported except in odd cases through questionable condensation methods. / Science, Faculty of / Chemistry, Department of / Graduate
2

The synthesis of some secondary amyl and hexyl homologues of dinitro ortho and para cresols

Hillman, Melville Ernest Douglas January 1954 (has links)
Eight new dinitro secondary amyl and hexylphenols of unequivocal structure were synthesized and characterized by their piperidine, morpholine and cyclohexylamine salts. The first step in the syntheses was the esterification of phenol to give phenyl acetate and phenyl propionate. A high temperature Fries rearrangement in the absence of solvent was used to convert the phenyl esters to o- and p-hydroxyaceto- and propiophenones. The alkyl o- and p-hydroxyphenyl ketones were then methylated with dimethylsulphate in an alkaline medium. The resulting methoxyacetophenones and methoxypropiophenones were reacted with Grignard reagents prepared from n- and isopropyl bromides. The tertiary alcohols thus obtained were dehydrated by refluxing in toluene, in the presence of iodine. The water in the water-toluene azeotrope was collected in a Dean and Stark tube. Nitrosyl chloride derivatives of the alkenes were prepared whenever possible, and analyzed for nitrogen. The alkenes were dissolved in ethanol and hydrogenated under 1000 p.s.i. pressure at 50° C. The resulting alkylanisoles were characterized as sulphonamides which were analyzed for both nitrogen and methoxyl content. The para alkylanisoles were demethylated by refluxing with pyridine hydrobromide at 200° C. The ortho alkyl anisoles were demethylated by refluxing with constant boiling hydriodic acid and phenol. The resulting alkylphenols were characterized as 3,5-dinitrobenzoate derivatives which were analyzed for nitrogen. The alkylphenols were nitrated to the dinitro derivativeswith concentrated nitric acid (density 1.50) in glacial acetic acid at -15° C. The piperidine, morpholine and cyclohexylamine salts were prepared by the addition of the amine to a benzene solution of the nitrophenol. The amine salts were analyzed for nitrogen. The alcohols, alkenes and alkylanisoles were analyzed for methoxyl values. Carbon and hydrogen analyses for the alkylphenols were also obtained. The phenols prepared were: 2-(o- and p-hydroxyphenyl)-pentane, 2-(o- and p-hydroxyphenyl)-3-methylbutane, 3-(o-and p-hydroxyphenyl)-hexane, 3-(o- and p-hydroxyphenyl)-2-methylpentane. A sample of "o-sec-amylphenol” obtained from Sharpies Chemicals Inc. was found to consist mainly of 2-(o-hydroxy-phenyl)-pentane. A Fries rearrangement of phenyl trimethyl acetate (phenyl pivalate) gave phenol as the only identifiable product, together with possible degraded and polysubstituted mixtures. o-Hydroxytrimethylacetophenone (o-hydroxypivalophenone) could not be separated or identified in the distillate. / Science, Faculty of / Chemistry, Department of / Graduate
3

Compound formation in phenol-cresol mixtures

Beaver, Jacob Julius, January 1921 (has links)
Thesis (Ph. D.)--Columbia University, 1921. / Vita.
4

A study of some of the reactions of 6-amino, m-cresol ...

Connitt, George Herbert, January 1927 (has links)
Thesis (Ph. D.)--Columbia University, 1928. / Vita. Bibliography: p. [45-46].
5

Compound formation in phenol-cresol mixtures

Beaver, Jacob Julius, January 1921 (has links)
Thesis (Ph. D.)--Columbia University, 1921. / Vita.
6

PREPARATIONS AND REACTIONS OF CRESOL DIANIONS AND DIMETHYLPHENOL TRIANIONS (ANISOLE, ALKYL PHENOL, CYCLOPHANE).

SIAHAAN, TERUNA JAYA. January 1986 (has links)
With n-BuLi/t-BuOK (Lochmann's base), protons are removed from the hydroxyl and methyl groups of cresols to give cresol dianions in yields of 85% (o), 95% (m), and 40% (p). These dianions react with alkyl halides, MeSiCl, Bu₃Sn Cl, CO₂, and oxidizing agents at carbon only, and with dialkyl sulfates at both carbon and oxygen. Thus phenol derivatives bearing primary alkyl groups can be prepared from the corresponding methylphenol via cresol dianions. Dimethylphenol trianions were prepared with Lochmann's base from all six isomers of dimethylphenol. 3,5-Dimethylphenol trianion was prepared in the best yield (80%); 2,3-, 2,4-, 2,5-, 2,6-, and 3,4-dimethylphenol trianions were prepared in 19.5%, 19%, 52%, 36%, and 44% yields, respectively. The common side products were dianions and tetraanions (in the latter, the fourth proton was usually pulled from the ring ortho to oxygen). These trianions were reacted with dimethyl sulfate to give anisole derivatives. 3,5-Dimethoxytoluene monoanion was reacted with n-BuBr to give a mixture of O,O'-dimethylolivetol (40%) and 4-butyl-3,5-dimethoxytoluene (34%).
7

Crédito e desenvolvimento rural: uma comparação entre microcrédito e crédito cooperativo no Vale do Itajaí /

Spengler, Carlos Alberto, Schiochet, Valmor, Universidade Regional de Blumenau. Programa de Pós-Graduação em Desenvolvimento Regional. January 2009 (has links) (PDF)
Orientador: Valmor Schiochet . / Dissertação (mestrado) - Universidade Regional de Blumenau, Centro de Ciências Humanas e da Comunicação, Programa de Pós-Graduação em Desenvolvimento Regional.
8

The Separation and Determination of Ortho, Meta and Para Cresols by Gas-Liquid Chromatography

Marquez, Jose G. January 1964 (has links)
No description available.
9

Clinical and experimental studies on reactions to formocresol, with special reference to pulpotomy

Mejàre, Ingegerd. January 1979 (has links)
Thesis--University of Lund. / Includes reprints of the author's articles. Includes bibliographical references.
10

An optimisation study into the synthesis of o-cresol novolacs.

Sitetyana, Pindiwe 19 May 2008 (has links)
The phenolic resin chemistry is an old chemistry that started in the late 1800’s. A lot of research work to gain understanding of phenolic resins has been done and reported in literature. However, most of the studies are based on phenol novolac resins. It was necessary to acquire more knowledge on specifically o-cresol novolac (OCN) resins because of the interest in the production of these resins. The chemistry in question was new to Sasol and one of the major objectives of doing this work was to build in-house competency in this field. This was achieved by first investigating whether the available feed materials containing certain impurities can be used to synthesise o-cresol novolacs with set specifications of purity and physical characteristics. The suitability of the Sasol o-cresol in terms of its contamination with sulfur (which is sometimes found in relatively higher amounts due to operating conditions) was investigated. The results showed that the sulfur in o-cresol did not have a significant contribution in the sulfur of the OCN. Another contaminant, formic acid, an auto-oxidation product found in formalin solutions was also investigated. It was also observed that, at formic acid levels of up to 4000 ppm, there was no effect on the softening point of the OCN. Secondly, it was important to study and understand the effect of different reaction variables on the quality of the OCN resins. The effect of formaldehyde: o-cresol molar ratio was investigated, the softening point increased with the increase in the molar ratio. The effects of other reaction variables (catalyst, reaction time, temperature and formaldehyde feed rate) on the softening point of the OCN were also investigated using p-toluenesulfonic acid and oxalic acid as catalysts. With p-toluenesulfonic acid as a catalyst, the temperature had no effect on the softening point, while all the other variables showed an effect on this parameter. A softening point model was formulated, which predicted the softening point with 98% accuracy. With oxalic acid, only the amount of catalyst had an effect. In addition, the chemical structures of these compounds were studied using 13C-NMR spectroscopy. The focus was on the isomer distribution of the methylene linkages. / Prof. D.B.G. Williams

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