Clean electrons

Electrochemical processes are particularly well suited for the manufacture of fine chemicals in view of their high sjjecificity (almost comparable to that offered by enzymes), the smaller number of steps required, adoption of milder conditions, lack of scale-up problems, avoidance of effluents, etc. The ease with which oxidation and/or reduction can be carried out with the practically mass-free clean electrons makes electrochemical processes well suited for such jobs, including paired synthesis in effect, we use electricity as a reagent . Consider a standard chemical oxidant like manganic or chromic sulphate. Here, a stoichiometric amount of the reduced salt will be formed the disposal of which can be a serious problem. If we adopt an electrochemical process, then the reduced salt is converted into the desired oxidized salt. 

Uses Manufacture of fluorocarbon refrigerants, fluorocarbon plastics, and propellants solvent for natural products analytical chemistry cleansing agent soil fumigant insecticides preparation of chlorodifluoromethane, methyl fluoride, salicylaldehyde cleaning electronic circuit boards in fire extinguishers. 

Uses. Solvent for cleaning electronic equipment and degreasing of machinery refrigerant dry cleaning agent... 

In 1974, F. Sherwood Rowland and Mario Molina, who shared the 1995 Nobel Prize in Chemistry with Crutzen, showed that chlorine from photolyzed chlorofluorocarbons (CFCs) such as CF2C12 and CFCI3, which were used as supposedly inert refrigerants, solvents for cleaning electronic components, plastic foam blowing agents, and aerosol spray propellants, can also catalyze ozone loss. Subsequently, the chlorine monoxide molecule CIO, which is involved in the chlorine-catalyzed ozone destruction cycle, has been shown to be present in the holes in the ozone layer and to correlate inversely with... 

Iron complexes with organic ligands are widely used as such reservoirs. For example, the stable 19-electron complex cyclopentadienyl benzene iron(I) is a clean electron reservoir that has a sufficiently negative oxidation potential and can be easily made, stored, and handled and can be weighed accurately (Alonso Astruc 2000). 

It is seen that q = 0 for a clean coupling reaction and that q = 1 for a clean electron transfer reaction. The value of k,n is close to that for a diffusion-controlled process, whereas the value of kjv increases when E /a- moves in the negative direction. Accordingly, a plot of q versus Ea/a- will give rise to an S-shaped curve from which the potential E, corresponding to q = 0.5 may be determined. Once the value of Ej, is known, the standard potential for the reduction of R of the Marcus theory [128]. 

Fluoroinert [3M]. TM for a series of per-fluorinated liquids used for cleaning electronic com-... 

Use Cleaning electronic and mechanical instruments and controls, degreasing motors, cleaning liquid oxygen equipment, and motion-picture and television film and magnetic tape. 

MAJOR PRODUCT APPLICATIONS paints (non-skid coatings, textured paints, flatting), chemical carrier, cleaning and polishing liquids, soaps, tooth polishing pastes and powders, cleaning electronic circuit boards... 

Chlorofluorocarbons were devised as nonflammable, nontoxic, noncorrosive alternatives to refrigerants, such as sulfur dioxide, ammonia, and chloromethane.130 Their uses grew to include blowing agents for foam insulation, aerosol propellants, and solvents for cleaning electronic parts.131 Typical compounds are the following ... 

PPG Trichlor. [PPG Industries] Tri-chlorethylene solvent for vapor degreasing, cold cleaning, cleaning electronic componrats, synthesizing chemicals. 

Chemically, OXSOL 2000 is alpha, alpha, alpha-trifluorotoluene, an HFC. OXSOL 2000 has a number of desirable properties for precision cleaning, electronics cleaning, aerosol applications, and wipe cleaning. It is a pure compound, with a relatively fast evaporation rate and toluene-like odor. In its pure form, OXSOL 2000 is a good replacement for hexane, toluene, and VM P naphtha where a rapid evaporation rate is desirable and a flammable solvent can be used safely. In addition, OXSOL 2000 can be blended with classical solvents like trichloroethylene yielding non-flammable, very fast evaporating compositions. 

The second part of this handbook (Chapters 14-25) is devoted more to the industrial use of solvents. Formulating with solvents applied in a broad range of industrial areas such as biotechnology, dry cleaning, electronic industry, food industry, paints and coatings, petroleum refining industry, pharmaceutical industry, textile industry, to mention only a few, is extensively described in Chapter 14. Standard and special mefriods of solvent detection and solvent analysis as well as the problem of residual solvents in various products, particularly in pharmaceutical ones, are the topics of Chapters 15 and 16. 

Isopropanol is specified to clean electronic devices such as contact pins in connectors as well as the connectors, magnetic tape and disk heads, lenses of lasers in optical disc drives, and LCD/LED and glass computer monitor screens. Isopropanol is also used for removal of thermal (solder) paste from integrated circuit packages, and restoration of vinyl records. 

Optically stimulated electron emission (OSEE) (cleaning) Electron emission from a metal surface under ultraviolet light radiation. Changes in OSEE can be used to quanhfy surface contamination. 

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