Showing papers on "Methanol published in 1968"

Rapid methods of lipid extraction and fatty acid methyl ester preparation for seed and leaf tissue with special remarks on preventing the accumulation of lipid contaminants

Abstract: An all-glass apparatus for the extraction, evaporation and methanolysis of small amounts of lipids has been designed. The special methanolysis tubes fit to an apparatus capable of handling 10 samples simultaneously. Reaction times of 2-5 minutes are effective for the conversion of seed oil triglycerides to fatty acid methyl esters by heating in methanol containing sodium methoxide. The same equipment is useful for preparation of fatty acid methyl esters from leaf lipids (neutral lipids, phospho-and galacto-lipids) by consecutive 5 minute treatments with NaOH in methanol and BF 3 in methanol. In studies on the further treatment of the methyl esters obtained from rape seed it has been found that the crude preparation possessed an oxidative stability which permitted evaporation under a stream of air; the pure esters obtained from preparative thin layer chromatography on the other hand had to be treated much more carefully. Gas chromatographic analysis of the crude and pure esters yielded the same fatty acid composition when the esters were protected by an antioxidant during the thin layer chromatographic separation; without this protection losses, mainly of the linolenic ester, infrequently occurred. The partial extraction of lipids in the all-glass equipment gave an extract with the same fatty acid composition as the complete extract prepared in stainless steel tubes according to Troeng thus permitting comparison of data obtained on seed samples by either extraction method. The steel tubes are prefered when larger amounts of material are available, the glass extractors for smaller amounts due to problems of contamination of esters when using the former method. Several sources of laboratory contaminants, troublesome errors in lipid micro-analysis, have been traced and their TLC and GLC patterns have been analysed. Based on these experiences, several precautions are recommended in order to minimize the contamination problem in lipid microanalysis.

Methanol Metabolism in the Monkey

Abstract: The peroxidative system involving hepatic catalase plays a major role in the oxidation of methanol in the rat (1), but in the monkey the peroxidative mechanism does not appear to be important. This conclusion is based on the following observations: (a) ethanol and methanol were about equally reactive with the peroxidative system, but ethanol was much more reactive with the alcohol dehydrogenase system than methanol. Ethanol was a much more effective inhibitor of methanol oxidation in the intact monkey than it was in the rat, which is what would be expected if methanol is oxidized by the alcohol dehydrogenase system in the monkey, but by the peroxidative system in the rat. (b) By similar reasoning, 1-butanol was a stronger inhibitor of methanol oxidation in the monkey than it should have been if the peroxidative system was involved. (c) 3-Amino-1,2,4-triazole, a potent inhibitor of hepatic catalase, greatly reduced methanol oxidation in the rat, but had no measurable effect on methanol oxidation in the monkey. (d) Ethylene glycol stimulated the rate of methanol oxidation in the rat, probably as a result of an increased H2O2 production that occurs when glycolic acid, a metabolite of ethylene glycol, is oxidized to glyoxylic acid (6,7); no such stimulation was seen in the monkey. Studies in vitro which measured the methanol-oxidizing activity of hepatic alcohol dehydrogenase isolated from monkeys also support the view that this enzyme is largely responsible for methanol oxidation in this species.

Kalafungin, a new broad spectrum antibiotic

Abstract: Lomofungin is a new antibiotic which is extracted from the fermentation broth of Streptomyces lomondensis var. lomondensis with methyl ethyl ketone and purified by crystallization. It is an acidic olive-yellow colored compound with a molecular formula C15H10N2O6 and a molecular weight of 314. It exhibits ultraviolet and visible absorption maxima at 221, 270, 311, 375 and 439mμ in 0.01N methanolic hydrochloric acid, and at 239, 265, 299, 342, 478 in 0.01N aqueous sodium hydroxide. Lomofungin does not melt below 320°C.It is soluble in dimethylformamide, alkaline water, acidic acetone and acidic methyl ethyl ketone but only slightly soluble in water, methanol, cyclohexane, acetone, ether or ethyl acetate.

Role of adsorbed species for the anodic methanol oxidation on platinum in acidic electrolytes

Abstract: The effect of anions on the oxidation of chemisorbed carbonaceous species formed during the anodic oxidation of methanol is attributed to a displacement of the discharge of water molecules to more positive potentials with increasing adsorbability of the anions. The efficiency of CO2 production decreases from about 90% at a methanol bulk concentration of 0·01 M to about 10% at 5 M in 0·5 M H2SO4 at constant potential between 0·5 and 0·7 V. The comparison of the maximum rates of individual reactions with the net rate and the efficiency of CO2 production leads to the conclusion that the CO2 evolution does not occur predominantly by the formation and oxidation of the carbonaceous species.

γ-Radiolysis of a Binary Mixture of Methanol and Water. The Formation of Formaldehyde in the Radiolysis of Liquid Methanol

Abstract: The γ radiolysis of a binary mixture of methanol and water over a wide concentration range has been investigated. The observed yields of products are expressed as a linear function of the electron fraction of methanol in the mixture. The yields of molecular hydrogen were also determined. Analyzing the results on reasonable assumptions, one could obtain for neutral water, Ge\barsw=2.3–2.5 and GOHw≥2.6. It was concluded that, in the radiolysis of methanol, formaldehyde may be produced through the decomposition of CH2OH radicals in the spur region, not by the disproportionation of these radicals.

Methyl radical reactions with isopropanol and methanol, their ethers and their deuterated derivatives

Abstract: The reactions of methyl radicals with three isotopically different isopropanols three isotopically different methanols and the undeuterated ethers (diisopropyl and dimethyl ethers) have been investigated. The photolysis of acetone or acetone-d6 has been used to generate methyl radicals or trideuteromethyl radicals. An isotopic exchange reaction between acetone and alcohols makes it necessary to work with isotopically compatible pairs. Values for Arrhenius parameters, based on Shepp's rate-constant for the combination of methyl radicals, are as follows : [graphic omitted] Primary isotope effects in the alkyl groups of these alcohols are larger than expected solely on the basis of zero-point-energy difference : at 150°, (kCH/kCD) is ca. 8 for methanol and ca. 6.5 for isopropanol. These values, which resemble those for ethanol and for isobutane, taken together with the corresponding activation-energy differences, suggest that tunnelling may again be important. A secondary reaction, disproportionation between the radicals · C(CH3)2OH and CH3, is important in attack on isopropanol. It gives rise to an apparent enhancement of reactivity of the hydroxyl groups, to a spurious secondary isotope effect and, unless allowance is made, to a low value for the A-factor. The corresponding reaction does not appear to be significant in methanol or ethanol systems. In dimethyl ether, the reactivity of each methyl group is the same as in methanol but in diisopropyl ether there is steric hindrance and the alpha hydrogen atoms are less accessible than in the alcohol.

Direct quantitative gas chromatographic separation of C2-C6 fatty acids, methanol, and ethyl alcohol in aqueous microbial fermentation media.

Abstract: A method is described for the direct quantitative gas chromatographic separation of C2-C6 lower fatty acid homologues, methanol, and ethyl alcohol in aqueous microbial fermentation media. A hydrogen flame detector and a single-phase solid column packing, comprising beads of a polyaromatic resin (polystyrene cross-linked with divinyl benzene), were employed. Direct injections of 1 to 10 μliters of aqueous culture supernatant fluids were made. Quantitative recoveries of C2-C6 acids added to culture supernatant fluids were obtained.

Ammonia and methanol production

Abstract: A PROCESS IS PROVIDED FOR THE MANUFACTURE OF METHANOL AND AMMONIA COMPRISING OPERATING SEQUENTIALLY A HIGH PRESSURE HYDROCARBON REFORMING ZONE IN SERIES WITH A LOW PRESSURE METHANOL SYNTHESIS ZONE, IN SERIES WITH A WATER SHIFT CONVERSION ZONE, IN SERIES WITH A CARBON DIOXIDE REMOVAL ZONE, IN SERIES WITH AN AMMONIA SYNTHESIS ZONE. SUCH COMBINATION TAKE ADVANTAGES OF SAID NEWLY DEVELOPED LOW PRESSURE METHANOL PROCESS AND THEREBY SAVES SUBSTANTIAL OPERATING COATS IN CARBON DIOXIDES COMPRESSION IN ADDITION TO SUBSTANTIALLY INVESTMENT COSTS BY UTILIZING A SINGLE PROCESS TRAIN INSTEAD OF THE HERETOFORE EMPLOYED INDEPENDENT METHANOL AND AMMONIA PLANTS.

A variable-temperature nuclear magnetic resonance study of complexes of borane and boron trihalides with acetone, diethyl ether, dimethyl ether, n,n-dimethylformamide, methanol, and tetrahydrofuran.

Abstract: : A proton and boron-11 chemical shift and coordination number study of complexes of diborane and the boron trihalides with dimethyl ether, diethyl ether, methanol, tetrahydrofuran, and, to a small extent, acetone and N,N-dimethylformamide has been completed. At low temperatures, separate proton resonance signals are observed for bulk solvent and solvent molecules complexed with the boron species. Coordination numbers were measured by the direct integration of the separate signals. The chemical shift separations for bulk and complexed solvent signals decreased in the order BBr3 > BCl3 > BF3 > BH3. An attempt is made to relate these separations to the coordinating abilities of the boron halides. The proton chemical shift data of the bases were correlated with some diborane 11B and 1H nuclear magnetic resonance results to obtain information concerning the species present in the ether-diborane solution. (Author)

Measurement of the vapor pressure of methanol-n-decanol and ethanol-n-decanol mixtures

Abstract: Molar excess Gibbs free energies of mixtures of methanol and ethanol with n-decanol were obtained from static vapor pressure measurements over the temperature range 20–50 °C The molar excess entro

Kinetics of Association of Carbon Monoxide with Haemoglobin at Low Temperature

Abstract: Carbon dioxide binds to haemoglobin at −55° C, in methanol and water, in a manner basically similar to binding in ordinary conditions.

The thermal decomposition of t-butyl methyl ether

Abstract: The rates of the thermal decomposition of t-butyl methyl ether have been measured in the range 433-495o. The reaction products are isobutene and methanol, and the kinetic form is first order. The Arrhenius equation K1 = 1014.38exp(-61535/RT) sec-1 describes the variation of rate with temperature. The reaction behaviour is consistent with a unimolecular mechanism. Comparison of the results with those obtained for the production of isobutene from various t-butyl compounds indicates that the reaction has some degree of heterolytic character.

Reactions of oxygen atoms with 2-propanol and methanol

Abstract: An investigation of the reaction of 2-propanol at 25 °C with oxygen atoms in the ground electronic state, O(3P), and, as a corollary, with the excited mercury atoms, Hg 6(3P1), has been carried out. The reaction of oxygen atoms with methanol at 25 °C has also been briefly studied. The general mechanism of reaction of O(3P) atoms with simple alcohols is discussed.

Behavior of Methyl Iodide in the Reaction of Acetic Acid Synthesis from Methanol and Carbon Monoxide

Abstract: The reaction of methyl iodide with carbon monoxide in the presence of cobalt (II) iodide as the catalyst has been investigated to know the effect of methyl iodide on the acetic acid synthesis from methanol and carbon monoxide catalyzed by the same catalyst. The reaction, CH3I+CO+H2O→CH3COOH+HI, does not take place before the methyl iodide used has been hydrolyzed completely into methanol and sodium iodide by adding enough amount of sodium acetate (CH3I+CH3COONa+H2O→CH3OH+NaI+CH3COOH). Methyl iodide also strongly inhibits the reaction of methanol with carbon monoxide catalyzed by cobalt (II) ion or dicobalt octacarbonyl, although iodide ion promotes the reaction effectively. The promotion effect of iodide ion has been discussed by considering the effect of an additive on carbonylation reactions in terms of a labilizing ligand and a non-labilizing ligand and a possible reaction scheme of methanol with carbon monoxide catalyzed by cobalt(II) iodide has been proposed.

Anodic Processes of Acetate Ion in Methanol and in Glacial Acetic Acid at Various Anode Materials

Abstract: The anodes used in this study were platinum, gold, palladium, lead dioxide, and graphite. The normal Kolbe process, the formation of ethane (and methane) and carbon dioxide, can be realized at a potential higher than 2.0v (vs. SCE) in both methanol and glacial acetic acid. In methanol, only platinum and gold seem to be suitable for realizing the process. In glacial acetic acid, however, all of the anodes except graphite can be used successfully for the same process. Another process, the formation of methyl acetate, occurs in both solvents at graphite in the potential range 1.4–2.0v. A side reaction observed in methanol at palladium, graphite, and lead dioxide was the formation of formaldehyde (and methyl formate in case of lead dioxide) which occurs at potentials as low as 1.2v.

Stabilized tetrafluoroethylene-fluoroolefin copolymers having methyl ester end-groups and process for producing same

Abstract: Stabilized tetrafluoroethylene-fluoroolefin copolymers having methyl ester end-groups are produced from tetrafluoroethylenefluoroolefin copolymers having carboxylic acid end-groups and acid fluoride end-groups by contacting the polymer with methanol at from about 65-200* C. for the carboxylic acid end-groups and from about 0-200* C. for the acid fluoride end-groups and then drying the stabilized polymer.