Potassium hydroxide fusion

All four dissolution procedures studied were found to be suitable for arsenic determinations in biological marine samples, but only one (potassium hydroxide fusion) yielded accurate results for antimony in marine sediments and only two (sodium hydroxide fusion or a nitricperchloric-hydrofluoric acid digestion in sealed Teflon vessels) were appropriate for determination of selenium in marine sediments. Thus, the development of a single procedure for the simultaneous determination of arsenic, antimony and selenium (and perhaps other hydride-forming elements) in marine materials by hydride generation inductively coupled plasma atomic emission spectrometry requires careful consideration not only of the oxidation-reduction chemistry of these elements and its influence on the hydride generation process but also of the chemistry of dissolution of these elements. 

In contrast to earlier methods which involved alcoholic potassium hydroxide fusion of 3-chloro-benzanthrone, this route affords pure isoviolanthrone, free of isomers. 

In degrading ring D and the side chain of biosynthetic cholesterol, Cornforth, Gore, and Popjak demonstrated that potassium hydroxide fusion can be used to effect oxidation of an aldehyde to an acid. The aldehyde is converted into the oxime and this is fused with potassium hydroxide the reaction may proceed through the nitrile as an intermediate ... 

As above indicated, in a sodium hydroxide, or potassium hydroxide fusion of a sulphonic add. besides the phenol, the alkali sulphite is formed, e.g.. -... 

The technique of potassium hydroxide fusion-reaction gas chromatography has been applied to the determination of alkyl and aryl groups in polysiloxanes. The method involves the quantitative cleavage of all organic substituents bonded to silicon, producing the corresponding hydrocarbons ... 

Method 3.6 Determination of Amino Groups in Aromatic Polyamides, Polyimides and Polyamides-imides. Potassium Hydroxide Fusion Gas Chromatography [158, 159]... 

METHOD 49 - DETERMINATION OF AMINO GROUPS IN AROMATIC POLYAMIDES, POLYIMIDES AND POLY(AMIDES-IMIDES). POTASSIUM HYDROXIDE FUSION-GAS CHROMATOGRAPHY. ... 

Upon warming with 10-20 per cent, sodium or potassium hydroxide solution, no ammonia is evolved (distinction from primary amides). The base, however, is usually liberated upon fusion with soda lime (see experimental details in Section IV,175) and at the same time the acyl group yields a hydrocarbon. Thus benz-p-toluidide affords p-tolu-idine and benzene. 

Alkali Fusion. Tha alkaU fusion of castor oil using sodium or potassium hydroxide in the presence of catalysts to spHt the ricinoleate molecule, results in two different products depending on reaction conditions (37,38). At lower (180—200°C) reaction temperatures using one mole of alkah, methylhexyl ketone and 10-hydroxydecanoic acid are prepared. The 10-hydroxydecanoic acid is formed in good yield when either castor oil or methyl ricinoleate [141-24-2] is fused in the presence of a high boiling unhindered primary or secondary alcohol such as 1- or 2-octanol. An increase to two moles of alkali/mole ricinoleate and a temperature of 250—275°C produces capryl alcohol [123-96-6] CgH gO, and sebacic acid [111-20-6] C QH gO, (39—41). Sebacic acid is used in the manufacture of nylon-6,10. 

Methylsuccinic acid has been prepared by the pyrolysis of tartaric acid from 1,2-dibromopropane or allyl halides by the action of potassium cyanide followed by hydrolysis by reduction of itaconic, citraconic, and mesaconic acids by hydrolysis of ketovalerolactonecarboxylic acid by decarboxylation of 1,1,2-propane tricarboxylic acid by oxidation of /3-methylcyclo-hexanone by fusion of gamboge with alkali by hydrog. nation and condensation of sodium lactate over nickel oxide from acetoacetic ester by successive alkylation with a methyl halide and a monohaloacetic ester by hydrolysis of oi-methyl-o -oxalosuccinic ester or a-methyl-a -acetosuccinic ester by action of hot, concentrated potassium hydroxide upon methyl-succinaldehyde dioxime from the ammonium salt of a-methyl-butyric acid by oxidation with. hydrogen peroxide from /9-methyllevulinic acid by oxidation with dilute nitric acid or hypobromite from /J-methyladipic acid and from the decomposition products of glyceric acid and pyruvic acid. The method described above is a modification of that of Higginbotham and Lapworth. ... 

If the NHj group is eliminated first, as in the fusion of eolehieine with potassium hydroxide, and the product is oxidised with permanganate, terephthalie and trimellitic (benzene 1 2 4-tricarboxylic) acids are formed, which should come from a third benzene ring. 

Leonard and Elderfield have also carried out degradation experiments with alstonine and its tetrahydride. On fusion with potassium hydroxide at 300-350° in nitrogen, alstonine furnishes barman (p. 490) and indefinite basic and acidic fractions. Tetrahydroalstonine on like treatment produces barman, worharman, and three unidentified bases, each of which fluoresces blue in alcoholic hydrochloric acid Base A, C4,H4gN2, m.p. 171-5 to 172-5°, forms a picrate, m.p. > 267° is probably a substituted -carboline. Base B, or 18 3, gives apicrate, m.p. 261° (dec.). Base C,... 

Rauwolscine gives colour reactions like those of yohimbine and the absorption curves of the hydrochlorides of the two alkaloids are very similar. Heated to 300°/5 mm. rauwolscinic acid forms barman (p. 490) and 3-ethylindole and on fusion with potassium hydroxide decomposes into indole-2-carboxylic acid, isophthalic acid, barman and an unidentified indole derivative. Rauwolscine itself on distillation with zinc dust produces barman, 2-methylindole (scatole) and tsoquinoline. It is suggested that the alkaloid has the skeletal strueture suggested by Seholz (formula XIV, p. 508) for yohimbine, the positions of the hydroxyl and earbomethoxy grouf s being still imdetermined. 

Thymol has since been synthetised by a number of chemists, but only two of those syntheses need be considered in this connection because of their close relationship to the present method, Dinesmann (D.E.P., 125,097 (1900)) obtain a patent for a process of making thymol from 2-brom-p-cymene. This process consists in sulphonating 2-brom-p-cymene, obtaining 2-brom-3- or 5-sulphonic acid, which, when heated with zinc dust and ammonia in an autoclave at 170°, gives cymene-3-sulphonic acid. This compound on fusion with potassium hydroxide gives thymol. 

Phenylacetylene (2, 67). It is stated in the directions that the distilling flask is heated until a temperature of 200° is reached and at that temperature the potassium hydroxide which is used is molten. The potassium hydroxide usually available contains sufficient moisture so that it will liquefy at 200 If pure dry potassium hydroxide is used, it is necessary to add a little water so that the fusion point will be lowered to the point indicated... 

Substances which are insoluble or only partially soluble in acids are brought into solution by fusion with the appropriate reagent. The most commonly used fusion reagents, or fluxes as they are called, are anhydrous sodium carbonate, either alone or, less frequently, mixed with potassium nitrate or sodium peroxide potassium pyrosulphate, or sodium pyrosulphate sodium peroxide sodium hydroxide or potassium hydroxide. Anhydrous lithium metaborate has found favour as a flux, especially for materials containing silica 12 when the resulting fused mass is dissolved in dilute acids, no separation of silica takes place as it does when a sodium carbonate melt is similarly treated. Other advantages claimed for lithium metaborate are the following. 

Analytical decomposition of powdered diamond by fusion with potassium hydroxide may become explosive. This can be avoided by fusion with a potassium carbonate-sodium carbonate mixture, followed by addition of small portions of potassium nitrite or nitrate. 

This displacement is accomplished by heating the sulphonated derivative at a high temperature with sodium or potassium hydroxide [64]. Typical is the preparation of 2-naphthol (4.15) from naphthalene-2-sulphonic acid (Scheme 4.21). Displacement of the sulphonic acid group occurs more readily when it is located at the a- rather then at the P-position, the former requiring a fusion temperature of about 200 °C and the latter one of about 250 °C. This difference in reactivity can be exploited to prepare naphtholsulphonic acids by fusion of suitable naphthalenedisulphonic acids. 

It was established in 1929 by Liittringhaus and Neresheimer that 4,4,-bibenzanthronyl (6.77) is an intermediate in the formation of violanthrone. Thus, compound 6.77 results when an Ullmann reaction is carried out on 4-chlorobenzanthrone the same product is obtained when benzanthrone reacts under relatively mild conditions (approximately 110 °C) with a mixture of potassium hydroxide and potassium acetate in 2-methylpropan-l-ol (isobutanol). Alkali fusion at a higher temperature then converts 4,4,-bibenzanthronyl into violanthrone. Use of aluminium chloride also leads to ring closure (Scholl reaction). 

In order to prepare the potassium salt, 20 g. of phenylglycine are made exactly neutral to phenolphthalein with 2 A-potassium hydroxide solution (about 70 c.c. are required), and the clear solution is then evaporated to dryness on the water bath. Fot the indoxyl fusion the residue of salt must be dried in an oven at 100° for several hours. 

Indoxyl Fusion.2—A mixture of 15 g. of sodium hydroxide and 20 g. of potassium hydroxide is fused and carefully dehydrated by heating to about 500° in a nickel crucible. When the mass has barely solidified it is just remelted by gentle heating and poured into a Jena glass conical flask (capacity 100 c.c.) which is at a temperature of 220° in an oil bath. If this procedure is adopted there need be no fear that the glass will crack. 

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