Ethanolic NaOH Research Articles

Formation of sodium carbonate during the reaction of coal with a solution of sodium hydroxide in ethanol

Substantial amounts of sodium carbonate were formed during the reaction of a Wyoming subbituminous coal with a concentrated solution of NaOH in ethanol. Up to 8% of the feed carbon was converted to Na 2CO 3 in a temperature range 215–300 °C.

Improved Gas Chromatographic Determination of Sorbitan Fatty Acid Esters in Confectionery Products

Abstract A method is described for gas chromatographic (GC) determination of sorbitan fatty acid esters in confectionery products as sorbitan monostearate. A sample is homogenized with chloroform, filtered, dried, and saponified with 0.1N NaOH in ethanol 1 h at 80°C. The saponification mixture is acidified, washed with hexane, and dried. Isosorbide, 1,4-sorbitan, and D-sorbitol are each derivatized at 70°C with pyridine, hexamethyldisilazane, and trimethylchlorosilane. GC separation of the polyols as TMS (trimethylsilyl) derivatives was performed on a 2% Dexsil 300 column temperature-programmed from 120 to 250°C at 107 min. The sorbitan monostearate content of the sample was calculated from the polyols, using the appropriate conversion factor. The procedure was applied to ice creams, cakes, and other confectionery products. Average recoveries from samples spiked with 1.0% Span 60 (sorbitan monostearate) were 91-96% for isosorbide, 83-99% for 1,4-sorbitan, and 82-98% for D-sorbitol. The detection limit was approximately 0.01%.

ChemInform Abstract: SYNTHESIS OF 2,2‐DIMETHYL‐2H‐PYRAN‐FUSED FLAVONOLS USING THE MODIFIED ALGAR‐FLYNN‐OYAMADA REACTION

AbstractDie Acetylhydroxychromene (I) bzw. (III) werden durch Kondensation mit Anisaldehyd und nachfolgende HzOg‐Oxidation in einer Ein‐ topfreaktion in die Flavonole (II) bzw. (IV) übergeführt (Ausb.‐Angaben in g).

Synthesis of 2,2-Dimethyl-2H-pyran-fused Flavonols Using the Modified Algar-Flynn-Oyamada Reaction

Abstract 6-Acetyl-2,2-dimethylchromenes when separately condensed with p-anisaldehyde in the presence of ethanolic NaOH and subsequently oxidized with alkaline hydrogen peroxide without isolating the intermediate chalcones afforded the corresponding 2,2-dimethyl-2H-pyran-fused flavonols respectvely in good yield. Thus, flavonols having free 3-hydroxyl and fused with 2,2-dimethyl-2H-pyran can be synthesized easily.

Synthesis of Dihydrojasmone from 1-Nitroheptane

A novel preparation method of dihydrojasmone has been developed using 1-nitroheptane as a starting material. 2, 5-Undecanedione, the precursor of dihydrajasmone, was synthesized in a satisfactory yield via Michael addition of the above nitro compound to methyl vinyl ketone followed by Nef reaction. Michael addition was carried out in ethanol with fairly good yield employing diisopropylamine as a catalyst. The conversion of the nitro group into carbonyl by Nef reaction was easily achieved with an excellent yield in ethanolic NaOH solution. Dihydrojasmone was obtained by base-catalyzed cyclization of the 1, 4-diketone obtained according to the established method.

The course of reaction of 4-nitrobenzyl bromide and 5-nitrofurfuryl bromide with bases: Operation of anion-radical mechanism

4-Nitrobenzyl bromide (I) - contrary to 5-nitrofurfuryl bromide (V) - does not react with hard bases in an electron-transfer chain reaction, giving instead product of SN2 reaction. However, its reaction with soft bases affords 1,2-bis(4-nitrophenyl)ethane (III) as anion-radical mechanism product. 5-Nitrofurfuryl bromide reacts with hard bases to give 1,2-bis(5-nitro-2-furyl)ethylene (VI) whereas with soft bases 1,2-bis(5-nitro-2-furyl)ethane (VII) is formed. The derivative VII on reaction with ethanolic NaOH reacts by α-E1cB mechanism under formation of the ethylene derivative VI. The derivative III does not react by this mechanism. The solvent and base effects on the formation of charge-transfer complexes in the initial stage of these reactions in relation to the reaction mechanism are discussed.

Linkage of the N-terminal peptide portion of renin substrate to the remainder of the protein Evidence for an alkali-labile Tyr-Ser and against an ester bond

Tetradecapeptide renin substrate (Asp-Arg-Val-Tyr-Ile-His-Pro-Phe-His-Leu-Leu-Val-Tyr-Ser) was originally isolated by treatment of protein renin substrate with trypsin. Because trypsin is not known to cleave at a serine bond, but does have esterase activity, and because NaOH in ethanol was reported also to produce the tetradecapeptide from the protein substrate, an ester linkage of the peptide to the protein was proposed. In the present study protein renin substrate has been treated with several ‘specific’ esterolytic reagents: 1 M NH 2OH, pH 9.5, 40°C, 1.5 h; 1 M hydrazine, pH 9, 40°C, 5 h; and, for comparison with previous work, 1 M NaOH in 95% ethanol, 25°C, 0.5 h. A peptide product was isolated by ultrafiltration, Bio-Gel P-2 chromatography, and ion-exchange chromatography. Identification of the peptide was by its localization during ion-exchange chromatography and high voltage electrophoresis as well as by amino acid analysis. In each case the tridecapeptide, Asp-Arg-Val-Tyr-Ile-His-Pro-Phe-His-Leu-Leu-Val-Tyr was isolated, i.e. tetradecapeptide minus its C-terminal serine or des-Ser 14 tetradecapeptide. Treatment of the isolated peptide with renin yielded angiotensin I. Authentic tetradecapeptide subjected to action of the same esterolytic reagents, produced the same tridecapeptide as was obtained from protein renin substrate. The Tyr-Ser of the tetradecapeptide, like that of some other model peptides including adreno corticotropic hormone (ACTH), appears to be very sensitive to cleavage under these conditions. In contrast, no peptide product was obtained when protein renin substrate was treated with LiBH 4 in tetrahydrofuran, a reagent which quantitatively cleaves ester bonds. We conclude that the N-terminal peptide portion of renin substrate is linked to the remainder of the protein through a labile peptide bond. The proposal of an ester bond linkage of peptide to protein appears to be inconsistent with the current evidence.

PAS reaction performed on semithin Epon sections following removal of the resin by NaOH in absolute ethanol

Different results of PAS reaction performed on semithin sections of Epon-embedded tissues were obtained when the sections were exposed for various time intervals to saturated solution of NaOH in absolute ethanol, the reagent known to dissolve the resin and facilitate staining. In the untreated sections only glycogen revealed strong PAS reaction, most mucosubstances reacted weakly or not at all. After 1 to 5 min of NaOH in absolute ethanol treatment results observed were in accordance with those usually seen in paraffin sections. When, however, the time of Epon-dissolving procedure was longer than 10 min, most tissue structures demonstrated positive, largely diffuse staining. The mechanism of the observed effect and its significance for the application of PAS reaction to Epon sections are discussed.

The etching of thick Araldite-embedded sections for scanning electron microscopy.

SUMMARYA rapid method of correlation of information from the images of the scanning electron microscope, the transmission electron microscope and the light microscope, from biological tissues embedded in epoxy‐resin. It allows a perception in depth at the SEM level of areas already defined by the other two modes. One micrometre sections of Araldite‐embedded tissues are cut, dried onto glass cover slips, and the embedding medium etched away, with a saturated solution of NaOH in absolute ethanol. After washing in absolute ethanol and distilled water the resultant osmicated ‘skeleton’ is coated and viewed in the SEM.

Rapid and simple method for the quantitative extraction of corn endosperm proteins

Rapid quantitative extraction of corn endosperm proteins is accomplished by presolubilization of the zeins in 70% ethanol ( v v ), followed by addition of dilute NaOH solution to the ethanolic slurry. The effectiveness of this technique rests primarily on the rapid solubilization of the zeins in weakly ethanolic dilute NaOH solution and on the prescribed sequence of addition of reagents. The extraction conditions of endosperms of vitreous and floury phenotypes differ as to sample particle size and optimum concentrations of NaOH.

Extraction of Glucosinolates from Rapeseed

Five processes for the aqueous and ethanolic extraction of glucosinolates from rapeseed meal, ground seed and the intact seed were evaluated. All methods were effective in the detoxification of low and intermediate glucosinolate samples but two processes, in which 3.0min boiling was used to inactivate myrosinase., failed to fully detoxify the high glucosinolate sample. The boiling treatment maintained sulfur levels in the oil below 10ppm while the ethanolic NaOH extraction eliminated the sulfur contamination of the oil. The aqueous extracts from the meal experiment contained a high proportion of the meal nitrogen while losses of oil and nitrogen occurred in the ground seed extractions. The diffusion extractions of glucosinolates from the intact seeds were effective in controlling these losses and the yields of oil and meal exceeded the other processes.Other disadvantages of the meal extraction method were the long (15h) extraction period, slow drying of the meal slurry and the dark appearance of the product. The aqueous extraction of ground seed was relatively rapid (1h) but the drying of the wet slurry and recovery of extract solids would increase the costs of the process. Each of the three diffusion extraction processes required large quantities of solvent and 6h for the passive diffusion of glucosinolates from the rapeseed. The most effective solvent, ethanolic NaOH, denatured the meal proteins.All of the extracted meals contained about 20% crude fiber. Dehulling the seed after diffusion extraction or air classification of the meal would be necessary to produce a high protein, food-grade rapeseed flour.

Biquinones—III : The dimerisation of 1,4-naphthaquinones

2-Methyl-1,4-naphthaquinones, substituted at C-3 by alkyl, aralkyl, allyl, aryl or halogen groups, react in aqueous ethanolic NaOH to give dehydro-dimers, namely 1,2-bis(1,4-naphthaquinon-2-yl)ethanes. The reaction is analogous to the formation of bibenzyls from nitrotoluenes in basic media. In tBuOH containing tBuOK, 3-benzyl-2-methyl-1,4-naphthaquinone also undergoes oxidation at the benzyl carbon atom to give phthiocol and benzaldehyde, as well as dimer; allyl groups are cleaved similarly. A mechanism is proposed which also accounts for the final stage in the Dam-Karrer colour test for vitamin K. 2-Hydroxy-1,4-naphthaquinones are oxidised by persulphate to 2,2′-dihydroxy-3,3′-bi-1,4-naphtha-quinonyls.