Cleaning base baths

Prolonged cleaning by base baths or HF can remove ceramic markings. 

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). 

Organic stopcock greases are insoluble in a base bath and will prevent the base bath from cleaning any contamination beneath the grease. 

If your pump used silicone oil and has left crusty remains that will not drain, a base bath is recommended (see Sec. 4.1.7). Place a cork in the end of the drainage tube (fire-polish as before), pour in a base bath solution, and let the pump sit for an hour or two. Because a base bath is highly flammable, be sure to unplug all electrical components of the pump before you begin this type of cleaning process. 

Uses Formulated cone, for personal care cleaning and bath prods. base for liq. dishwash... 

The metallic substrate, clean and rinsed, is immersed wet in the plating cell. The base metals which are usually plated present an essentially metallic surface to the electrolyte, and the slight corrosive action of the rinse water in preventing the formation of any substantial oxide film is important. A critical balance of corrosion processes in the initial stages is vital to successful electroplating, and for this reason there is a severe restriction on the composition of the electroplating bath which may be used for a particular substrate. This will be discussed later. The substrate is made the cathode of the cell it may be immersed without applied potential ( dead entry) or may be already part of a circuit which is completed as soon as the substrate touches the electrolyte ( live entry). Live entry reduces the tendency for the plating electrolyte to corrode the substrate in the period before the surface... 

Procedure Dissolve accurately 22.5 mg of /ram-clomiphene citrate and 52.5 mg of cis-clomiphene citrate (approx. 1 2.3) into 10 ml of DW in a clean 50 ml separating funnel. Add to it 1 ml solution of sodium hydroxide (5% w/v in DW). In the alkaline medium the base is liberated which is extracted successively with 3 portions of solvent ether (10 ml each). The combined ethereal layer is washed with two portions of DW (10 ml each). The resulting ethereal fraction is dried over anhydrous sodium sulphate, filter, evaporate to diyness carefully over an electric water-bath and dissolve the residue in 1 ml of CS2. Now, record the absorption curve in a 0.2 mm cell over the range 12.50 to 14.00 pm. Calculate the absorbance for the peaks at 13.16 and 13.51 pm respectively by employing the base-line method (see section 3. l. B in this chapter) between the minima at 12.66 and 13.89 pm. 

Laboratory Equipment Based on the Ultrasonic Cleaning Bath... 

Some of the problems associated with using a commercial cleaning bath can be overcome using an ultrasonic bath purpose built for sonochemistiy. Typically these baths are designed with a large area transducer in the base and external cooling/thermostat-ting (Fig. 7.9). 

Solid tertiary amines and imines may be quantitatively alkylated by gas-solid and solid-solid techniques. Methylation of quinuclidine (176) to give the methoiodide 177 is achieved waste-free by exposure of 176 to a stoichiometric amount of methyl iodide vapor (Scheme 23). Difficulties with the disintegration of the crystals of 177 from those of 176 (reaction step 3) are overcome by ultrasound treatment from a cleaning bath at 20 °C [22]. Numerous applications of this technique to tertiary amines can be envisaged. However, solid Troeger s base (with interlocked layers, i.e., no possibility for molecular migrations) is not alkylated by methyl iodide vapor unless an excess of the vapor is applied to induce intermediate (partial) liquefying of the solid [22]. 

Never clean cuvettes or any optically polished glassware with ethanolic KOH or other strong base, as this will cause etching. All cuvettes should be cleaned carefully with 0.5% detergent solution, in a sonicator bath, or in a cuvette washer. 

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