Caustic soda mixtures

The process operated by ACl is outlined in Figure 7. Bales of cotton linter are opened, cooked in dilute caustic soda, and bleached with sodium hypochlorite. The resulting highly purified ceUulose is mixed with pre-precipitated basic copper sulfate in the dissolver, and 24—28% ammonium hydroxide cooled to below 20°C is added. The mixture is agitated until dissolution is complete. If necessary, air is introduced to aUow oxidative depolymerization and hence a lowering of the dope viscosity. 

Fusion with caustic soda at 500—800°C in an iron cmcible is an effective method for opening pyrochlores and columbites (20). The reaction mixture is flaked and leached with water to yield an insoluble niobate which can be converted to niobic acid in yields >90 wt% by washing with hydrochloric acid. 

Azoic Dyes. These are used to produce cost-effective heavy yellow, orange, red, maroon, navy blue, brown, and black shades and are ptinted alongside other dye classes to extend the coloristic possibiUties for the designer. Two approaches are adopted. The common method ia the United States is to use both a naphthol derivative and a stabilized color base, usually in the form of a diazo imino compound in the same print paste. This mixture is soluble in dilute caustic soda and no coupling takes place at this stage. The dried prints are passed through steam at 100—105°C that contains acetic and/or formic acid vapor. As neutralization takes place on the print, the coupling occurs rapidly and the insoluble azoic dye is formed. 

Nitro-filter cloths are composed of cellulose nitrate, which is an ester of cellulose. Any chemical compound that will saponify the ester will destroy the cloth. Caustic soda or potash in strengths of 2% at 70° C or over alkali sulfides, polysulfides and sulfohydrates or mixtures of ethyl alcohol and ether, ethyl, amyl and butyl acetates, pyridine, ferrous sulfates, and other reducing agents are detrimental to the cloth. 

Mercaptan extraction is used to reduce the total sulfur content of the fuel. When potassium isobutyrate and sodium cresylate are added to caustic soda, the solubility of the higher mercaptans is increased and they can be extracted from the oil. To remove traces of hydrogen sulfide and alkyl phenols, the oil is pretreated with caustic soda in a packed column or other mixing device. The mixture is allowed to settle and the product water washed before storage. 

Dipping solution Dissolve 100 mg of 8-anilinonaphthalene-l-sulfonic acid ammonium salt in a mixture of 40 ml caustic soda solution (c = 0.1 mol/1) and 57 ml of an aqueous solution containing 21 g citric acid monohydrate and 8 g sodium hydroxide per hter. 

Laudanine, C20H25O4N, was isolated by Hesse. The crude alkaloid is purified by recrj stallisation from dilute alcohol for the removal of small quantities of cryptopine, or it may be dissolved in acetic acid and the solution poured into dilute caustic soda, when this impurity is precipitated and laudanine may be recovered from the filtrate by addition of ammonium chloride. It still contains its isomeride laudanidine, which may be separated by repeated crystallisation of the hydrochlorides, laudanidine accumulating in the aqueous mother liquors. The base crystallises from dilute alcohol, or from a mixture of alcohol and chloroform in rhombic prisms, m.p. 166°, [a]o 0°. It dissolves in solutions of alkali hydroxides, fornung metallic derivatives, which are precipitated by excess of alkali, but is nearly insoluble in solution of ammonia. The salts crystallise well ... 

Add the acetone to the mixture of the hydroxylamine hydrochloride and caustic soda in a small flask. The flask is then corked and left for twenty-four hours, during which the... 

Boil the tartaric acid and caustic soda solution for three hours in a round flask (I litre), or preferably in a tin bottle furnished with reflu. condenser. The use of a tin vessel obviates certain clitli-cultiesof filtration which the solution of the silica by the action of the alkali on the glass entails. The liquid, after boilinjg, is carefully neutralised with cone, hydrochloric acid (it is acl is-able to remove a little of the solution beforehand in case overshooting the mark) and an excess of calcium chloride solution is added to the hot liquid. The mixture is left overni hl. and the calcium salts filtered off at the pump, washed with water, and well pressed. 

Reaction.—Make a solution of 4 grams stannous chloride in TO c.c. cone, hydrochloric acid, add 2 grams aminoazobenzene, and boil for a few minutes. On cooling ciystals of the hydrochlorides of aniline and yi-phenylenediamine separate out. The liquid is filtered and washed with a little cone, hydrochloric acid to remove the tin salts. If the precipitate is dissolved in water and made alkaline with caustic soda, a mixture of liquid aniline and solid/-phenylenediamine is precipitated, from which the former may be removed by filtering, washing, and draining on a porous plate. 

The sulphanilic acid is dissolved in the sodium carbonate (i mol.) solution and the sodium nitrite (i mol.) solution added. The mixture is cooled in ice, and the solution of hydrochloi ic acid (i mol.) gradually added. The solution of dimethylaniline (i mol.) is now poured in, and the liquid made alkaline with caustic soda. The separation of methyl orange at once begins, and is assisted by the addition of a little common salt (20 grams). The precipitate is filtered at the pump, and crystallised from hot water. Yield, nearly theoretical. 

Yttrium and lanthanum are both obtained from lanthanide minerals and the method of extraction depends on the particular mineral involved. Digestions with hydrochloric acid, sulfuric acid, or caustic soda are all used to extract the mixture of metal salts. Prior to the Second World War the separation of these mixtures was effected by fractional crystallizations, sometimes numbered in their thousands. However, during the period 1940-45 the main interest in separating these elements was in order to purify and characterize them more fully. The realization that they are also major constituents of the products of nuclear fission effected a dramatic sharpening of interest in the USA. As a result, ion-exchange techniques were developed and, together with selective complexation and solvent extraction, these have now completely supplanted the older methods of separation (p. 1228). In cases where the free metals are required, reduction of the trifluorides with metallic calcium can be used. 

A mixture of 10 parts of benzaldehyde, 15 parts of acetaldehyde, 900 parts of water, and 10 parts of 10 per cent, solution of caustic soda are allowed to stand for ten days at 30° with constant stirring. The cinnamic aldehyde formed is extracted with ether and purified by fractional distillation. 

Methyl cinnamate (16 parts) is dissolved in methyl alcohol (20 parts) and treated with bromine (20 parts). The mixture solidifies in the cold. It is shaken with a solution of caustic soda (12 parts) in water (24 parts), the temperature being kept down to 40°. After two hours the mixture is neutralised with dilute sulphuric acid, and an oily layer separates. This is mixed with water (to 250 parts) and sodium carbonate (5-5 parts) added, and the aldehyde distilled in a current of steam, and extracted with ether, and the ether evaporated. The yield is about 75 per cent, of the theoretical. 

The mixture is taken up with water and the base is extracted from the toluene with dilute hydrochloric acid. The hydrochloric solution is rendered alkaline with caustic soda, the base is separated with ether, dried, and after distillation of the ether fractionated in vacuo, BP at 0.05 mm Hg, 150° to 153°C. The basic ether is then dissolved in dry ether, and ether saturated with dry hydrogen chloride is added dropwise with stirring. An excess of hydrogen chloride must be avoided as it may produce decomposition to the corresponding diphenyl ethylene. The ether-moist hydrochloride is preferably dried at once in vacuo and subsequently reprecipitated from acetone-ether and then again dried in vacuo over phosphorus pentoxide. Hydrochloride, MP 12B°C. 

A mixture of 1.5 mols of 1-(2 -hydroxyethyl)piperazine and 1 mol of p-chlorobenzhydryl chloride is heated at 150°C for 15 minutes. The substance is dissolved in water, basified by caustic soda and extracted with benzene. 

This condensate was washed with dilute caustic soda solution and dried over calcium chloride. The exit gases from this condenser were scrubbed with water and dilute caustic soda solution, dried and passed to a condenser cooled with a mixture of solid carbon dioxide and trichloroethylene which caused the unchanged 1,1,1-trifluoro-2-chloroethane to condense. This second condensate was then combined with the first and the mixture was fractionally distilled. 

Amixture of 3.4 gof 10-methoxy-4-(1 -methyl-4-piperidyl)-4H-ben2o[4,5]cyclohepta[1,2-b]-thiophen-4-ol base and 40 cc of 3 N hydrochloric acid is kept in a boiling water bath at 95°C to 100°C for 1 hour. The mixture is subsequently made alkaline with concentrated caustic soda solution at 20°C while cooling, and the free base Is extracted with chloroform. The chloroform solution is concentrated, and the residue is recrystalli2ed from ethanol/water 1 1. The pure 4-(1 -methyl-4-piperldylidene)-4H-ben2o[4,5]cyclohepta[1,2-b] thiophen-10(9H)-one base, having a melting point of 152°C to 153°C, is obtained in this manner. 

The mixture is then slowly heated to the boiling point of toluene and kept boiling for one hour under reflux. After the mixture has been allowed to cool the sodium chloride which precipitates is separated by extraction with water. The solution of toluene is then extracted with dilute hydrochloric acid. From the hydrochloric acid extract the basic substance is separated in the form of an oil by means of caustic soda solution and is introduced into ether. The ethereal solution Is dried with the aid of potassium carbonate and then distilled. 

Essentially the same procedure can be carried out, employing as alkali any strongly alkaline substance, such as caustic soda in methanol solution. Control of the reaction rate may be accomplished by the rate of the addition of reactants and the amount of cooling applied to the reaction mixture. Agitation is employed to insure efficient contact of the reactants. 

As described in U.S. Patent 2,507,631, 80 g of pulverized sodium amide are gradually added, while stirring and cooling, to a solution of 117 g of phenyl-acetonitrile and 113 g of 2-chloropyridine in 400 cc of absolute toluene. The mixture is then slowly heated to 110° to 120°C and maintained at this temperature for 1 hour. Water is added thereto after cooling, the toluene solution is shaken with dilute hydrochloric acid and the hydrochloric acid extracts are made alkaline with concentrated caustic soda solution. A solid mass is separated thereby which is taken up in acetic ester and distilled, a-phenyl-a-pvridyl-(2)-acetonitrile passing over at 150° to 155°C under 0.5 mm pressure. When re-crystallized from ethyl acetate it melts at 88° to 89°C, the yield amounting to 135 g. 

The mixture is stirred for 1 hour. Water and methanol are added and the resulting mixture is stirred for 1 hour, extracted wtih chloroform, and washed in sequence with 1% aqueous caustic soda, 5% aqueous sodium bicarbonate solution, and water. The resulting solution is dried over anhydrous sodium sulfate and the solvent is distilled off. By recrystallization of the residue from acetone petroleum ether, nicergoline is obtained, melting at 136° to 13B°C. 

When all the ethyl nitrite has been added, the reaction mixture is refluxed for approximately one hour, then concentrated to dryness under reduced pressure (25 to 30 mm Hg) and at a maximum temperature of 70°C. The crystalline residue is dissolved in 35 liters of water and adjusted to a pH of 8 to 9 by addition (with cooling and stirring) of 11 to 12 kg of caustic soda. The sodium chloride formed is filtered off, and the filter cake is washed with 20 liters of normal butyl alcohol. This wash liquid is used for the first extraction of the product from the aqueous filtrate. The filtrate is then further extracted with four successive 20-liter portions of n-butyl alcohol. 

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