Alkaline base bath

AICAR HCl, 4-Aminoimidazole-5-carboxamide HCl Alkaline base bath... 

Pt—Q—Salt, [Pt(NH3)2(HP04)] and [Pt(OH)3] (259,260). Chloride-based baths have been superseded by P-Salt-based baths, which are more stable and relatively easily prepared. Q-Salt baths offer even greater stabiUty and produce hard, bright films of low porosity. Plating under alkaline conditions employs salts of [Pt(OH3)] . These baths are easily regenerated but have low stabiUty. Platinum films have uses in the electronics industry for circuit repair, mask repair, platinum siUcide production, and interconnection fabrication (94). Vapor deposition of volatile platinum compounds such as [Pt(hfacac)2] and... 

Some disadvantages stem from the same phenomena impeded diffusion reduces the maximum practical rate of plating to well below that possible with aquocation baths. The cyanide ion is not entirely stable both oxidation and reduction products accumulate, including carbonate. Carbonate is also formed in the alkaline cyanide baths (all cyanide baths are alkaline except some based on aurocyanides) by absorption of COj from the air, and it is necessary either to replace or purify baths periodically. Much has been made of the toxicity of cyanides, but the other process solutions used in plating are generally extremely toxic and corrosive or caustic, and it is necessary to treat them all with respect. 

Tin anodes dissolve by etching corrosion in acid baths based on stannous salts, but in the alkaline stannate bath they undergo transpassive dissolution via an oxide film. In the latter the OH" ion is responsible for both film dissolution and for complexing the tin. Anodes must not be left idle because the film dissolves and thereafter corrosion produces the detrimental divalent stannite oxyanion. Anodes are introduced live at the start of deposition, and transpassive corrosion is established by observing the colour of the film... 

There appear to be no cases of selenide deposition from acidic baths. Se-lenosulphate is not stable under even mildly acidic conditions, and all selenourea-based baths have been alkaline ones. 

However, there are disadvantages to the base bath. First, it has some safety hazards. The alcohol is a potential fire hazard, and the bath s alkalinity is caustic to skin. The base bath is also a mild glass stripper. That is, instead of cleaning the glassware, it actually removes layers of glass (and any adjoining contamination). 

After the base bath has been drained, let the pump soak for a few minutes with an acid rinse (to stop any alkaline reactions on the glass surface). After three or four water rinses, follow with a distilled water rinse and finally some methanol to speed the drying process. Do not blow air through the pump to speed the drying process as most compressed air is full of oils and other particulates (although dry nitrogen is acceptable). Alternatively, you can place the house vacuum hose to the pump and draw the ambient air through the pump. Remember, any acids or bases must be neutralized before disposal. 

As opposed to the use of acid-based dye baths, water-soluble direct dyeing processes utilize a more alkaline dye bath with sodium chloride or sodium sulfate added to promote dye wlckability or uptake. The mixture is heated to near 100 prior to introducing cellulosic, natural, and polymeric fiber structures. 

Sulfite alkaline baths are mainly used in engineering applications to prodnce layers of pure gold with a range of properties, in particular hardness and ductility they are also used to deposit alloy coatings otherwise not achievable by cyanide based baths, in the electroforming of prosthetic dentistry and, to a minor extent, of decorative and jewelry items. 

Cosmetics and Personal Care Products. Alkanolamines ate important taw materials in the manufacture of creams (95—97), lotions, shampoos, soaps, and cosmetics. Soaps (98) formed from triethanolamine and fatty acids ate mild, with low alkalinity and excellent detergency. Triethanolamine lauryl sulfate is a common base for shampoos (99—101) and offers significant mildness over sodiumlauryl sulfate. Diethanolamine lauryl sulfate and fatty acid soaps of mono- and trietban olamine can also be used in shampoos and bubble bath formulations. Chemistry similar to that used in soluble oils and other emulsifiers is appUcable to cleansing creams and lotions (102,103). Alkanolamides or salts ate added to the shampoo base to give a smooth, dense foam (104). 

Pla.tinum, Platinum plating has found appHcation in the production of platinised titanium, niobium, or tantalum anodes which are used as insoluble anodes in many other plating solutions (see Metalanodes). Plating solutions were often based on platinum "P" salt, which is diamminedinitroplatiniim (IT). A dinitroplatinite sulfate—sulfuric acid bath has been used to plate direcdy onto titanium (129). This bath contains 5 g/L of the platinum salt, pH adjusted to 2.0 with sulfuric acid. The bath is operated at 40°C at 10—100 A/m. Other baths based on chloroplatinic acid have been used in both acid and alkaline formulations the acid bath uses 20 g/L of the platinum salt and 300 g/L hydrochloric acid at 65° C and 10—200 A/m. The alkaline bath uses 10 g/L of the platinum salt, 60 g/L of ammonium phosphate and ammonium hydroxide to give a pH of 2.5—9.0. The alkaline bath can be plated directly onto nickel-base alloys acid baths require a gold strike on most metals. 

Toner, accelerator or oxidizing agent This is alkaline in nature, say, of sodium nitrite (NaN02) base and may be added to accelerate the process. At a very high temperature, however, above 70°C, it becomes ineffective. The bath temperature must therefore be kept below this. 

One gram of 6,7-dihydro-5H-dibenz[c,e] azepine hydrochloride was dissolved in water, made alkaline with concentrated ammonia, and the resultant base extracted twice with benzene. The benzene layers were combined, dried with anhydrous potassium carbonate, and mixed with 0.261 g of allyl bromide at 25°-30°C. The reaction solution became turbid within a few minutes and showed a considerable crystalline deposit after standing 3 A days. The mixture was warmed VA hours on the steam bath in a loosely-stoppered flask, then cooled and filtered. The filtrate was washed twice with water and the benzene layer evaporated at diminished pressure. The liquid residue was dissolved in alcohol, shaken with charcoal and filtered. Addition to the filtrate of 0.3 gram of 85% phosphoric acid in alcohol gave a clear solution which, when seeded and rubbed, yielded 6-allyl-6,7-dihydro-5H-dlbenz[c,e] azepine phosphate, MP about 211°-215°C with decomposition. 

Dj Preparation of 1-Methyl-4-f5-Dibenzofa,e] Cycloheptatrienylidenel-Piperidine The hydrochloride salt, 4.3 g, was suspended in 100 ml of warm water and the mixture made strongly alkaline by the addition of 15 ml of 5% sodium hydroxide. The mixture was extracted with four 50 ml portions of benzene and the extracts dried over sodium sulfate. Evaporation of the benzene on the steam-bath at reduced pressure left 3.7 g (97%) of the base, MP 110.3° to 111.3°C. Recrystallization from a mixture of alcohol and water gave product, MP 112.3° to 113.3°C. 

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. 

A solution of 3 methoxy-10-(3 chloro-2-methylpropyl)phenthia2ine (9.65 grams) and 4-hydroxypiperidine (6.1 grams) in xylene (lOcc) is heated under reflux for 5 hours. After cooling the mixture is diluted with ether (60 cc) and the basic compounds are extracted by agitation with water (30 cc) and 4N hydrochloric acid (20 cc). The aqueous acid phase is made alkaline with 4N sodium hydroxide solution (23 cc) and the liberated base is extracted with ether. The ethereal solution is washed with water (60 cc) and dried over sodium sulfate. Finally the solvent is distilled off on a water-bath. 

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