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Aqueous-Based Cleaning

Alkaline cleaning solutions contain builders (sodium salts of phosphates, carbonates, silicates, and hydroxides) and surfactants (detergents and soaps). Other additives may include anti-oxidants and stabilizers as well as small amounts of solvents. Acidic cleaning solutions may contain mineral acids (nitric, sulfuric, phosphoric, or hydrochloric), organic [Pg.37]

Unlike solvent and aqueous-based cleaning, plasma cleaning is based on reactions with surface contaminants at the molecular or atomic level. Two mechanisms are possible depending on the level of RF energy and the nature of the plasma gas. [Pg.166]

Aqueous-based cleaning agents containing water soluble organic components... [Pg.898]

Aqueous-based cleaning agents containing water soluble organic components There is a large number of products on the market that are mixtures of water and water-soluble organic solvents. These media are recommended for removal of solder paste, SMT adhesives, and flux residues from stencils, misprints and populated reflowed PCBs."... [Pg.64]

Soap is prepared by the basic hydrolysis or saponification of a triacylglycerol. Heating an animal fat or vegetable oil with aqueous base hydrolyzes the three esters to form glycerol and sodium salts of three fatty acids. These carboxylate salts are soaps, which clean away dirt because of their two structurally different regions. The nonpolar tail dissolves grease and oil and... [Pg.855]

Given the choice of equipment today and its cost relative to conventional solvent based cleaning, (see Ch. 10 by Huse and Smith), the advantages of SCF cleaning make it very attractive compared to aqueous or organic based systems. Capabilities of solvent tunability... [Pg.278]

This method is unusually mild, using neutral conditions and low temperatures (20 °C and less). It tolerates a number of functional groups in the components (e.g. acetals, esters, alkenes, etc.)- The alcohol, the carboxylic acid and triphenylphosphine are treated dropwise in an inert solvent (dichloromethane, THF, ether) with diethyl azodicarboxylate (DEAD). The ester is formed rapidly. However, tedious chromatography is frequently required to remove the by-products, triphenylphosphane oxide and hydrazo ester. The main value of the reaction lies in the clean inversion of configuration at a secondary carbinol center and in its selectivity towards primary hydroxy groups (vide infra). Inversions are usually performed with benzoic or p-nitrobenzoic acid. The benzoates are purified and saponified with aqueous base to furnish the inverted alcohols in overall yields of ca. 50%. Elimination is the main side reaction. Thus, from (44) 75% of the desired Sn2 product (45) is formed, along with 25% of the elimination product (46) (equation 19). The mechanism of the reaction has been clarified to the point that betaine (47) is the pri-... [Pg.333]

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