Aqueous washing effect

In the discovery laboratory, diol 4 produced by this dihydroxylation method was conveniently converted to 5 via a two-step procedure (Scheme 3.5). " - Oxidative cleavage of 4 by NaI04 (1 equiv) gave dialdehyde 15 in aqueous dichloroethane. Aqueous washes effectively removed NalO, salts, and the extracts were treated with benzylamine (1.05 equiv), dried by filtration through a cotton plug, then added to NaBH(OAc)3 (3.6 equiv). Conversion to 5 was complete within hours. Aqueous workup and silica gel pad filtration of the extracts gave 5 in 82 to 95% yield. 

As the temperature of dilute aqueous solutions containing ethoxylated nonionic surfactants is increased, the solutions may turn cloudy at a certain temperature, called the cloud point. At or above the cloud point, the cloudy solution may separate into two isotropic phases, one concentrated in surfactant (coacervate phase) and the other containing a low concentration of surfactant (dilute phase). As an example of the importance of this phenomena, detergency is sometimes optimum just below the cloud point, but a reduction in the washing effect can occur above the cloud point (95). However, the phase separation can improve acidizing operations in oil reservoirs (96) For surfactant mixtures, of particular interest is the effect of mixture composition on the cloud point and the distribution of components between the two phases above the cloud point. 

The aqueous Na2C0, and molten NaOH/KOH treatments, followed by acid washes, effectively removed many trace elements from the coals studied. 

In the aqueous washing liquor the fabric surface and the pigment soil are charged negatively due to the adsorption of OH- ions and anionic surfactants and this leads to an electrostatic repulsion. In addition to this effect, a disjoining pressure occurs in the adsorbed... 

It is not surprising, however, that contaminants deposited in hair from aqueous solutions are not as readily removed by normal hygienic practices as those deposited by vapors. For one, normal shampooing and showering involves only short contact times with the aqueous wash medium, i.e., in the vicinity of 5 min. Such contact times are too short for the effective removal of drug contaminants deposited from aqueous solutions. It is precisely because of this situation that we use protracted contact times of at least 30 min in our laboratory wash procedures. 

The allylmagnesium halide in ether is slowly added to a suspension or solution of the metal halide at 0°C or lower. Addition at low T improves yields and is essential for the synthesis of thermally unstable, homoleptic allyl complexes. The complexes are isolated by evaporation of the reaction mixture and extraction into an aromatic or alkane solvent. Purification is effected by crystallization or sublimation. When stable allyl compounds are prepared, an aqueous wash of the reaction mixture can be used to remove Mg salts and xs RMgX or -Li reagent the crude products can then be isolated from the resultant organic layer. 

In the present study, we assessed the effect of heating and aqueous washing of mechanically separated seal meat (MSSM) and mechanically separated chicken meat (MSCM) on the content of sulfhydryl groups and disulfide bonds in their proteins. An attempt was made to correlate the content of sulfhydryl groups with changes in the solubility and thermal coagulation of mechanically separated meat proteins. 

Obsolete uses of urea peroxohydrate, as a convenient source of aqueous hydrogen peroxide, include the chemical deburring of metals, as a topical disinfectant and mouth wash, and as a hairdresser s bleach. In the 1990s the compound has been studied as a laboratory oxidant in organic chemistry (99,100). It effects epoxidation, the Baeyer-Villiger reaction, oxidation of aromatic amines to nitro compounds, and the conversion of sodium and nitrogen compounds to S—O and N—O compounds. 

Generally, monochloroacetic acid [79-11-8] (MCA) is added to the reaction slurry containing sufficient excess sodium hydroxide to neutralize the MCA and effect its reaction. The use of esters of MCA has also been reported (52). Common reaction diluents are isopropyl alcohol, /-butyl alcohol, or ethyl alcohol (53,54). Dimethoxyethane has also been reported to be effective (55). The product is isolated and washed with aqueous alcohol or acetone to remove by-product salts. Unpurified cmde grades are generally prepared in the absence of diluents (56—59). 

Common impurities found in aldehydes are the corresponding alcohols, aldols and water from selfcondensation, and the corresponding acids formed by autoxidation. Acids can be removed by shaking with aqueous 10% sodium bicarbonate solution. The organic liquid is then washed with water. It is dried with anhydrous sodium sulfate or magnesium sulfate and then fractionally distilled. Water soluble aldehydes must be dissolved in a suitable solvent such as diethyl ether before being washed in this way. Further purification can be effected via the bisulfite derivative (see pp. 57 and 59) or the Schiff base formed with aniline or benzidine. Solid aldehydes can be dissolved in diethyl ether and purified as above. Alternatively, they can be steam distilled, then sublimed and crystallised from toluene or petroleum ether. 

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