Norman R. Hunter

Autoxidation and yellowing of methyl linolenate

The autoxidation of fatty esters of linseed oil is studied extensively, and the products formed from these reactions are identified. The mechanism suggested for autoxidation, helps to understand fat deterioration resulting in offensive odours and flavours, and to develop new antioxidants to prevent this decomposition. The oxidation following oxidative copolymerization should be investigated in order to understand and to develop new methodology to prevent yellowing. Although the yellowing of indoor oil paints could be prevented to an extent, no compound is known to completely inhibit this process nor has the cause for this yellow colouration been isolated, leaving the doors wide open for further investigation.

DIRECT CATALYTIC CONVERSION OF METHANE TO HIGHER HYDROCARBONS

Abstract Using a plug-flow reactor we have been able to demonstrate the conversion of pure methane gas to liquid hydrocarbons via the intermediate formation of methanol. The reaction Was carried out at an intermediate pressure (about 20 atm) and moderate temperature (about 400°C). In the first stage of the reactor methane and oxygen react to produce methanol. In the second stage the methanol was converted by HZSM-5 catalyst to a mixture of hydrocarbons. Analysis of the reaction products showed that all of the oxygen Was used in the reaction. Apart from the unconverted methane the product was composed of oxides of carboy water and C3+ hydrocarbons. Interestingly, among the liquid hydrocarbons, aromatics were found to be the major constituents.

THE PARTIAL OXIDATION OF CH4 TO CH3OH AT HIGH PRESSURE IN A PACKED REACTOR

ABSTRACT In a considered effort to improve turbulence and heat transfer while reducing reactant/product residence time (enhancing primary product preservation) in the partial oxidation of methane lo methanol, a glass lined reactor was packed successively with a scries of metal (beads), glass (beads) and carbon (“solid foam”). The metal surfaces included, nickel, copper, silver, line, tin and stainless steel. The surfaces were assessed in terms of the methanol selectivity determined in the conversion of methane to methanol, for each packing. The surfaces were found to favour methanol selectivity in the following order: glass (70%) > stainless steel (67%) > silver (64%) > nickel (63%) = zinc (63%) = tin (62%) > carbon (30%) > copper (0%). Copper promoted the direct and complete oxidation of methane to CO2 and H2O. No appreciable advantage other than improved heat transfer was found using the metal beads. Apparently the increased surface area of the beads had a negative effect on the methanol yield, since th...

The Synthesis and 13C-NMR Spectrum of 1,4-Dioxaspiro(4.5)deca-6,9-dien-2,8-dione

Abstract Recently there has been a great deal of interest in the preparation and use of selectively blocked quinones. Thus, Evans1 has used p-quinone monoketals and silyl cyanohydrin derivatives in synthetic studies. The parent p-benzoquinone mono(ethylene)ketal has been prepared2. Deslongchamps and co-workers3 used a spirolactone blocked o-quinone in an elegant total synthesis of ryanodol. Likewise, Wiesner4 has used a spirolactone blocked o-quinone in the synthesis of the C/D ring systems of chasmanine and napelline. Our interest in selective carbonyl-blocked quinones for synthesis led us to prepare the parent spirolactone blocked p-benzoquinone; 1,4-dioxaspiro(4.5)deca-6,9-dien-2,8-dione (1).

Some Characteristics of the Partial Oxidation of CH4 to CH3OH at High Pressures

The direct conversion of methane to methanol by the partial oxidation process at high pressure has been studied for about 60 years [1,2,3,4] but in the last 5 years more has been published [5–27] than in all previous years. The discrepancies in the results obtained by different workers seems to have been explained by the cool flame characteristics of the system, first described by Yarlaggada et al. [23] and later shown by Foulds et al. [8] and Charlton et al. [28] to exhibit to a hysteresis effect with change in reaction temperature. More recently, high selectively and conversion were obtained by Dooley [29] by using a pre-heater to accommodate the induction period, and a post reactor temperature quencher to prevent further oxidation of the methanol.

Solvent effects on the photocycloaddition and photoenolisation reactions of isophorone

The influence of solvent on two photochemical reactions of isophorone has been investigated. The photocycloaddition of isopropenyl acetate to isophorone (3,5,5-trimethylcyclohex-2-en-1-one) (1) is ...

Synthesis of 2-Acetoxy-2-Methoxy-4-Acetoxymethyl-3,5-Cyclohexadien-1-One by Lead Tetraacetate Oxidation of Homovanillic Acid

Abstract An efficient synthesis of the title compound is achieved when homovanillic acid is reacted with lead tetraacetate.

Glycerol, glucose and 2-acetoacetoxyethyl methacrylate: Effect on methyl linolenate oxidation and yellowing

The effect of glycerol, glucose and acetoacetoxyethyl methacrylate (AAEM) on autoxidation and yellowing of methyl linolenate has been investigated by nuclear magnetic resonance (NMR) and ultraviolet (UV)-Visible spectroscopies. The extent of autoxidation was determined by measuring the NMR integration of vinylic protons with respect to methoxy protons, an internal standard, as a function of time. The extent of yellowing was determined by measuring the difference in absorbance at 400 nm and 450 nm as a function of time. Glycerol and AAEM showed inhibition of autoxidation, but the most significant effect was observed with AAEM. Glucose enhanced the autoxidation of methyl linolenate. Inhibition of yellowing was observed with all these compounds, especially with glycerol and AAEM.

A novel solvolytic rearrangement of 2,2-dimethyl-5-(1-Bromomethylethylidene)-1, 3-dioxane-4,6-dione

Abstract Treatment of the title compound under basic aqueous conditions leads to 2,2-dimethyl-5-(2-ketopropyl)-1,3-dioxane-4,6-dione; the structure and mechanism of formation of this compound is described.

Effect of thioanisole and trimethylene sulfide on the oxidation and yellowing of methyl linolenate

The effect of thioanisole and trimethylene sulfide on the autoxidation and yellowing of methyl linolenate has been investigated by nuclear magnetic resonance (NMR) and ultraviolet visible spectroscopy, respectively. The progress of autoxidation was followed by measuring the NMR integration of vinylic protons with respect to methoxy protons, which served as the internal standard, as a function of time. The degree of yellowing was determined by measuring the difference in absorbance at 400 nm and 450 nm as a function of time. Both thioanisole and trimethylene sulfide enhanced the autoxidation of methyl linolenate. Inhibition of yellowing was observed only with trimethylene sulfide.