Sodium hydroxide fusion

The thymol can be separated by dissolving the product obtained by the sodium hydroxide fusion in water, acidulating with dilute sulphuric acid, and then steam distilling or it may be extracted with a suitable solvent or in any other appropriate manner. 

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. 

The sodium hydroxide fusion of the sodium anthraquinonemono-sulphonate is an abnormal reaction to the extent that besides the replacement of the sulphonic acid group by hydroxyl, a hydrogen atom is also oxidised to a hydroxyl group ... 

The 17o HNO reference solutions were prepared from distilled HNO and deionized distilled water. Analyses of the US Geological Survey reference samples were performed after dissolution by sodium hydroxide fusion (42). Reference solutions necessary for the analysis of the glass samples were prepared in a 27. NaCl-HCl matrix to match the total acid and salt content of the glass samples. 

The acid derivative of the unknown yields a hydrocarbon (CeHe) in a sodium hydroxide fusion reaction. Since sodium hydroxide fusion is a decarboxylation mechanism for aromatic carboxylic acid, the acid derivative is benzoic acid. This is confirmed by the fact that catalytic hydrogenation of CsHe yields CeHia/ which is the formula for cyclohexane. ... 

Determination of amino groups in aromatic polyamides, polyimides and poly(amides-imides). Sodium hydroxide fusion-gas chromatography... 

Kuhn-Roth oxidation of radioactive PHA obtained from labeled methionine resulted in recovery of radioactivity in the isolated sodium acetate. Sodium hydroxide fusion of the sodium acetate afforded only 4% of the radioactivity in the carbon dioxide formed. 

Prepare a solution of sodium plumbite by adding 10 per cent, sodium hydroxide solution to a few drops of about N lead acetate solution until the white precipitate of lead hydroxide initially formed just redissolves to a clear solution. Add 1 ml. of the fusion solution the presence of sulphiu- is indicated by a black precipitate of lead sulphide. 

The most popular device for fluoride analysis is the ion-selective electrode (see Electro analytical techniques). Analysis usiag the electrode is rapid and this is especially useful for dilute solutions and water analysis. Because the electrode responds only to free fluoride ion, care must be taken to convert complexed fluoride ions to free fluoride to obtain the total fluoride value (8). The fluoride electrode also can be used as an end poiat detector ia titration of fluoride usiag lanthanum nitrate [10099-59-9]. Often volumetric analysis by titration with thorium nitrate [13823-29-5] or lanthanum nitrate is the method of choice. The fluoride is preferably steam distilled from perchloric or sulfuric acid to prevent iaterference (9,10). Fusion with a sodium carbonate—sodium hydroxide mixture or sodium maybe required if the samples are covalent or iasoluble. 

Germanates. Germanates are usually prepared by the fusion of Ge02 with alkah oxides or carbonates in platinum cmcibles. Sodium heptagermanate [12195-31 -2], Na HGe O 4H2O, is precipitated by the neutrali2ation of a sodium hydroxide solution of Ge02 with hydrochloric acid to a pH above 7. 

Alkali Fusion of /u-Benzenedisulfonic Acid. Even though this process like the previous one is a very ancient one, it is still the main route for the synthesis of resorcinol. It has been described in detail previously and does not seem to have drastically evolved since 1980. It involves the reaction of benzene with sulfuric acid to form y -benzenedisulfonic acid which is then converted to its disulfonate sodium salt by treatment with sodium sulfite. In a second step, this salt is heated to 350°C in the presence of sodium hydroxide yielding the sodium resorcinate and sodium sulfite. 

In the manufacture of 2-naphthalenol, 2-naphthalenesulfonic acid must be converted to its sodium salt this can be done by adding sodium chloride to the acid, and by neutralizing with aqueous sodium hydroxide or neutralizing with the sodium sulfite by-product obtained in the caustic fusion of the sulfonate. The cmde sulfonation product, without isolation or purification of 2-naphthalenesulfonic acid, is used to make 1,6-, 2,6-, and 2,7-naphthalenedisulfonic acids and 1,3,6-naphthalenetrisulfonic acid by further sulfonation. By nitration, 5- and 8-nitro-2-naphthalenesulfonic acids, [89-69-1] and [117-41-9] respectively, are obtained, which are intermediates for Cleve s acid. All are dye intermediates. The cmde sulfonation product can be condensed with formaldehyde or alcohols or olefins to make valuable wetting, dispersing, and tanning agents. 

H-acid, l-hydroxy-3,6,8-ttisulfonic acid, which is one of the most important letter acids, is prepared as naphthalene is sulfonated with sulfuric acid to ttisulfonic acid. The product is then nitrated and neutralized with lime to produce the calcium salt of l-nitronaphthalene-3,6,8-ttisulfonic acid, which is then reduced to T-acid (Koch acid) with Fe and HCl modem processes use continuous catalytical hydrogenation with Ni catalyst. Hydrogenation has been performed in aqueous medium in the presence of Raney nickel or Raney Ni—Fe catalyst with a low catalyst consumption and better yield (51). Fusion of the T-acid with sodium hydroxide and neutralization with sulfuric acid yields H-acid. Azo dyes such as Direct Blue 15 [2429-74-5] (17) and Acid... 

Acid-cataly2ed hydroxylation of naphthalene with 90% hydrogen peroxide gives either 1-naphthol or 2-naphthiol at a 98% yield, depending on the acidity of the system and the solvent used. In anhydrous hydrogen fluoride or 70% HF—30% pyridine solution at — 10 to + 20°C, 1-naphthol is the product formed in > 98% selectivity. In contrast, 2-naphthol is obtained in hydroxylation in super acid (HF—BF, HF—SbF, HF—TaF, FSO H—SbF ) solution at — 60 to — 78°C in > 98% selectivity (57). Of the three commercial methods of manufacture, the pressure hydrolysis of 1-naphthaleneamine with aqueous sulfuric acid at 180°C has been abandoned, at least in the United States. The caustic fusion of sodium 1-naphthalenesulfonate with 50 wt % aqueous sodium hydroxide at ca 290°C followed by the neutralization gives 1-naphthalenol in a ca 90% yield. 

Naphthalenol. 2-Naphthol or p-naphthol or 2-hydroxynaphthalene/7i3 -/5 -i7 melts at 122°C and boils at 295°C, and forms colorless crystals of characteristic, phenoHc odor which darken on exposure to air or light. 2-Naphthol [135-19-3] is manufactured by fusion of sodium 2-naphthalenesulfonate with sodium hydroxide at ca 325°C, acidification of the drowned fusion mass which is quenched ia water, isolation and water-washing of the 2-naphthalenol, and vacuum distillation and flaking of the product. A continuous process of this type has been patented (69). The high sulfate content ia the primary effluent from 2-naphthol production is greatiy reduced ia modem production plants by the recovery of sodium sulfate. 

Naphthalenediol. 1,5-Dihydroxynaphthalene or Asurol is a colorless material which darkens on exposure to air. It is manufactured by the fusion of disodium 1,5-naphthalenedisulfonate with sodium hydroxide at ca 320°C in high yield. 1,5-Naphthalenediol is an important coupling component, giving ortho-a2o dyes which form complexes with chromium. The metallised dyes produce fast black shades on wool. 1,5-Naphthalenediol can be aminated with ammonia under pressure to 1,5-naphthalenediamine. 

Naphthalenediol. This compound darkens rapidly in air. It can be made by fusion of the sultone of 8-hydroxy-1-naphthaIenesulfonic acid with 50 wt % sodium hydroxide at 200—230°C, or by the hydrolytic desulfonation of l,8-dihydroxy-4-naphthalenesulfonic acid. The diol also reacts with ammonia to give 1,8-naphthalenediamine. 

Naphthalenediol. This diol is made by the fusion of sodium 2,7-naphthalenedisulfonate with molten sodium hydroxide at 280—300°C in ca 80% yield. A formaldehyde resin prepared from this diol has excellent erosion resistance, strength, and chemical inertness it is used as an ablative material in rocket-exhaust environments (76). 

Hydroxynaphthalenesulfonic acids are important as intermediates either for coupling components for a2o dyes or a2o components, as well as for synthetic tanning agents. Hydroxynaphthalenesulfonic acids can be manufactured either by sulfonation of naphthols or hydroxynaphthalenesulfonic acids, by acid hydrolysis of arninonaphthalenesulfonic acids, by fusion of sodium naphthalenepolysulfonates with sodium hydroxide, or by desulfonation or rearrangement of hydroxynaphthalenesulfonic acids (Table 6). 

Sodium metaniob ate (1 1) [67211-31-8] Na20 Nb20 7H20 or Na2Nb20g-7H20, separates as colorless triclinic crystals as a result of concentrating the mother Hquor from the preparation of the 7 6 sodium niobate by spontaneous evaporation. It also can be obtained by fusion of the anhydrous pentoxide in sodium hydroxide or carbonate. 

Substitution of various groups by amino or hydroxyl functions is industrially unimportant for the production of 2- and 4-aminophenol, but this type of reaction is used for the synthesis of 2- and 4-aminophenol derivatives. However, 3-aminophenol caimot be obtained easily by reduction. It is made by the reaction of 3-aminobenzenesulfonic acid [121 -47-1] with sodium hydroxide under fusion conditions (5—6 h 240—245°C). The product is purified by vacuum distillation (25). 

It can be prepared by heating resorcinol with an aqueous solution of dimethylamine and its hydrochloride at 200°C under pressure for 12 h (176). The treatment of dimethylaruline with oleum at 55—60°C, followed by fusion with sodium hydroxide at 270—300°C, also gives... 

The cleavage products of several sulfonates are utilized on an industrial scale (Fig. 3). The fusion of aromatic sulfonates with sodium hydroxide [1310-73-2J and other caustic alkalies produces phenohc salts (see Alkylphenols Phenol). Chlorinated aromatics are produced by treatment of an aromatic sulfonate with hydrochloric acid and sodium chlorate [7775-09-9J. Nitriles (qv) (see Supplement) can be produced by reaction of a sulfonate with a cyanide salt. Arenesulfonates can be converted to amines with the use of ammonia. This transformation is also rather facile using mono- and dialkylamines. 

Soluble Sta.nna.tes, Many metal staimates of formula M Sn(OH) are known. The two main commercial products are the soluble sodium and potassium salts, which are usually obtained by recovery from the alkaline detinning process. They are also produced by the fusion of stannic oxide with sodium hydroxide or potassium carbonate, respectively, followed by leaching and by direct electrolysis of tin metal in the respective caustic solutions in cells using cation-exchange membranes (27). Another route is the recovery from plating sludges. 

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. 

Fusions with lithium metaborate, 112 with sodium carbonate, 113 with sodium hydroxide, 113... 

Tyrer A process for making phenol by first sulfonating benzene. Benzene vapor was passed through hot sulfuric acid the excess of benzene served to remove the water formed in the reaction. The benzene sulfonic acid was then hydrolyzed by fusion with sodium hydroxide. Invented by D. Tyrer in 1916. See also Dennis-Bull. 

This procedure is based on the method of Smith, Opie, Waw-zonek, and Prichard3 for the preparation of 2,3,6-trimethyl-phenol. 3-Hydroxypyrene has been prepared by fusion of pyrene-3-sulfonic acid with sodium hydroxide 4 and by desul-fonation of 3-hydroxypyrene-5,8,10-trisulfonic acid with hot, dilute sulfuric acid.5... 

After sulphonation to 2-naphthylamine-l,5,7-trisulphonic acid, the labile 1-sulphonic acid substituent, which has now served its purpose, is eliminated by diluting the sulphonation mixture and heating. Fusion of the resulting disulphonic acid (4.42) with sodium hydroxide replaces the more labile 5-sulphonic acid group by a hydroxy group, forming ] acid. 

Goulden et al. [123] have described a semi-automated system for the determination of arsenic and selenium by hydride generation-industrively coupled plasma atomic-emission spectrometry. Sediments are brought into a solution by fusion with sodium hydroxide. 

Fusion with sodium hydroxide, as described by Goulden et al. [123] but using porcelain or nickel crucibles. 

Fusion with a flux such as sodium hydroxide, potassium bifluoride potassium pyrosulphate has been used extensively in the water industry. 

Naphthylamine and also its sulphonic acids are likewise employed technically for the manufacture of azo-dyes. In the same way a-naph-thol is made from naphthalene-a-sulphonic acid by fusion with sodium hydroxide although on a smaller scale than /3-naphthol. a-Naphthyla-mine, on the other hand, is obtained by the reduction of a-nitronaph-thalene (analogy to aniline). The fusion of alkali salts of arylsulphonic acids with alkali also serves technically for the production of pure phenol and of many phenol derivatives. 

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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