Methyl ethyl ketone solution

The effect of the medium on the rates and routes of liquid-phase oxidation reactions was investigated. The rate constants for chain propagation and termination upon dilution of methyl ethyl ketone with a nonpolar solvent—benzene— were shown to be consistent with the Kirkwood equation relating the constants for bimolecular reactions with the dielectric constant of the medium. The effect of solvents capable of forming hydrogen bonds with peroxy radicals appears to be more complicated. The rate constants for chain propagation and termination in aqueous methyl ethyl ketone solutions appear to be lower because of the lower reactivity of solvated R02. .. HOH radicals than of free RO radicals. The routes of oxidation reactions are a function of the competition between two R02 reaction routes. In the presence of water the reaction selectivity markedly increases, and acetic acid becomes the only oxidation product. 

To a methyl ethyl ketone solution of =Si—H containing polymers or copolymers, a cold solution (ca. -10 °C) of dimethyldioxirane in acetone was quickly added and reacted for 30 min at 0 °C. The mole ratio of dioxirane to polymer was ca. 1.2 1.3. The resulting silanol polymers or copolymers were obtained either in solution or precipitated into hexanes followed by vacuum dry at 40 °C for 24 h. 

By adding a nonsolvent (e.g., addition of isopropyl ether to methyl ethyl ketone solution of cellulose acetate butyrate)... 

Figure 1. Dynamic Mechanical Thermal Analysis of PMS-BD-PMS Triblock Copolymer Film Cast From Methyl Ethyl Ketone Solution. 

The carboxyl content of the polymer was determined by potentiometric titration with KOH in methyl ethyl ketone solution. The epoxy content of the polymer was determined by potentiometric titration with KOH in methyl ethyl ketone solution, using an excess of hydrogen chloride-acetone solution prior to the titration. 

The polymer is methylated with diazomethane in benzene, and the tacticity of the resulting poly(methyl methacrylate) is studied by NMR spectroscopy. The polymer exhibited 85% sindiotactic triads. Poly(methacrylic acid) prepared at 60°C in methyl ethyl ketone solution with AIBN was 57% syndiotactic. 

FIG U RE 4.14 The infrared spectrum of a polystyrene film cast from a methyl ethyl ketone solution. A KBr window was used. 

Once the solvent has evaporated, the infrared transparent window and cast film are placed in a holder in the sample compartment of an FTIR, and the spectrum is measured. Holders such as the ones shown in Figure 4.7 can be used for this purpose. Ideally, the background spectrum should be run on the same window holding the cast film. This technique could work on powders because they can be dissolved and evaporated on a window. However, once the window is held vertically to place it into the IR beam, the powder will fall off the window. This technique works with polymers because of their ability to form films and adhere to flat surfaces. A spectrum of polystyrene cast from methyl ethyl ketone solution onto a KBr window is shown in Figure 4.14. Note that the SNR is good, the baseline is flat, the sample peaks are well resolved and on scale, and there is no offset. 

Methyl ethyl ketone. Use the apparatus of Fig. Ill, 61, 1 but with a 500 ml. round-bottomed flask. Place 40 g. (50 ml.) of see. butyl alcohol, 100 ml. of water and a few fragments of porous porcelain in the flask. Dissolve 100 g. of sodium dichromate dihydrate in 125 ml. of water in a beaker and add very slowly and with constant sturing 80 ml. of concentrated sulphuric acid allow to cool, and transfer the resulting solution to the dropping funnel. Heat the flask on a wire gauze or in an air bath until the alcohol mixture commences to boil. Remove the flame and run in the dichromate solution slowly and at such a rate that the temperature... 

METHOD 4 [115]-80% phenol in aqueous H2SO4 soiution of pH 3 is brought to 50 C. 30% H2O2 is then added causing an exothermic reaction and a temperature of 15 C over 3-4 minutes time. 6% aqueous H2SO3 is added after 4.5 minutes, the solution quickly cooled and extracted with isopropyl acetone (Strike would think that another solvent like methyl ethyl ketone could be used) to give 60% catechol. 

Figure 10.8 shows two sets of data plotted according to these conventions, after correction for the effect of interference. In Fig. 10.8a, HC2/T is plotted against C2 for three different fractions of polystyrene in methyl ethyl ketone. Figure 10.8b shows Kc2/Rg versus C2 for solutions of polystyrene in cyclohexane at five different temperatures. These results are discussed further in the following example.

Membranes and Osmosis. Membranes based on PEI can be used for the dehydration of organic solvents such as 2-propanol, methyl ethyl ketone, and toluene (451), and for concentrating seawater (452—454). On exposure to ultrasound waves, aqueous PEI salt solutions and brominated poly(2,6-dimethylphenylene oxide) form stable emulsions from which it is possible to cast membranes in which submicrometer capsules of the salt solution ate embedded (455). The rate of release of the salt solution can be altered by surface—active substances. In membranes, PEI can act as a proton source in the generation of a photocurrent (456). The formation of a PEI coating on ion-exchange membranes modifies the transport properties and results in permanent selectivity of the membrane (457). The electrochemical testing of salts (458) is another possible appHcation of PEI. 

Biacetyl is produced by the dehydrogenation of 2,3-butanediol with a copper catalyst (290,291). Prior to the availabiUty of 2,3-butanediol, biacetyl was prepared by the nitrosation of methyl ethyl ketone and the hydrolysis of the resultant oxime. Other commercial routes include passing vinylacetylene into a solution of mercuric sulfate in sulfuric acid and decomposing the insoluble product with dilute hydrochloric acid (292), by the reaction of acetal with formaldehyde (293), by the acid-cataly2ed condensation of 1-hydroxyacetone with formaldehyde (294), and by fermentation of lactic acid bacterium (295—297). Acetoin [513-86-0] (3-hydroxy-2-butanone) is also coproduced in lactic acid fermentation. 

Anhydrous stannous chloride, a water-soluble white soHd, is the most economical source of stannous tin and is especially important in redox and plating reactions. Preparation of the anhydrous salt may be by direct reaction of chlorine and molten tin, heating tin in hydrogen chloride gas, or reducing stannic chloride solution with tin metal, followed by dehydration. It is soluble in a number of organic solvents (g/100 g solvent at 23°C) acetone 42.7, ethyl alcohol 54.4, methyl isobutyl carbinol 10.45, isopropyl alcohol 9.61, methyl ethyl ketone 9.43 isoamyl acetate 3.76, diethyl ether 0.49, and mineral spirits 0.03 it is insoluble in petroleum naphtha and xylene (2). 

Rapid, simple, quaUtative methods suitable for determining the presence of benzene in the workplace or surroundings have been utilized since the 1930s. Many early tests offered methods for detection of aromatics but were not specific for benzene. A straightforward test allowing selective detection of benzene involves nitration of a sample to y -dinitrobenzene and reaction of the resultant ether extract with an ethanoHc solution of sodium hydroxide and methyl ethyl ketone (2-butanone), followed by the addition of acetic acid to eliminate interferences from toluene and xylenes. Benzene imparts a persistent red color to the solution (87). The method is claimed to be sensitive to concentrations as low as 0.27 ppm benzene from 10 mL air samples. 

Organic solutions of HOCl can be prepared in near quantitative yield (98—99%) by extraction of CU -containing aqueous solutions of HOCl with polar solvents such as ketones, nitriles, and esters (131). These organic solutions of HOCl have been used to prepare chlorohydrins (132) and are especially useful for preparation of water-insoluble chlorohydrins. Hypochlorous acid in methyl ethyl ketone has also been used to prepare Ca(OCl)2, by reaction with CaO or Ca(OH)2 (133), and hydrazine by reaction with NH3 (134). 

Two solvent processes for preparation of Ca(OCl)2 have been described. In one, a CCl solution of /-C H OCl is allowed to react with a thin lime slurry and the aqueous phase, a solution of Ca(OCl)2, is evaporated to a product with a purity of >95% (217). In the other, a solution of HOCl in methyl ethyl ketone reacts with either CaO or Ca(OH)2 (133). FoUowing filtration, the residual solvent in the product is removed under vacuum. 

Ghlorohydrination with Nonaqueous Hypochlorous Acid. Because the presence of chloride ions has been shown to promote the formation of the dichloro by-product, it is desirable to perform the chlorohydrination in the absence of chloride ion. For this reason, methods have been reported to produce hypochlorous acid solutions free of chloride ions. A patented method (48) involves the extraction of hypochlorous acid with solvents such as methyl ethyl ketone [78-93-3J, acetonitrile, and ethyl acetate [141-78-6J. In one example hypochlorous acid was extracted from an aqueous brine with methyl ethyl ketone in a 98.9% yield based on the chlorine used. However, when propylene reacted with a 1 Af solution of hypochlorous acid in either methyl ethyl ketone or ethyl acetate, chlorohydrin yields of only 60—70% were obtained (10). 

They show good to excellent resistance to highly aromatic solvents, polar solvents, water and salt solutions, aqueous acids, dilute alkaline solutions, oxidative environments, amines, and methyl alcohol. Care must be taken in choice of proper gum and compound. Hexafluoropropylene-containing polymers are not recommended for use in contact with ammonia, strong caustic (50% sodium hydroxide above 70°C), and certain polar solvents such as methyl ethyl ketone and low molecular weight esters. However, perfluoroelastomers can withstand these fluids. Propylene-containing fluorocarbon polymers can tolerate strong caustic. 

Dihydrostreptomycin sesquisulfate [5490-27-7] M 461.4, m 250 (dec), 255-265 (dec), [a]p -92.4 (c 1, H2O), pKgsJd)-- 9.5 (NMe), pKes,(2,3) 13.4 (guanidino). It crystallises from H2O with MeOH, -BuOH or methyl ethyl ketone. The crystals are not hygroscopic like the amorphous powder, however both forms are soluble in H2O but the amorphous solid is about 10 times more soluble than the crystals. The free base also crystallises from H20-Me2C0 and has [a]p -92° (aqueous solution pH 7.0). [Solomons and Regina Science 109 515 7949 Wolf et al. Science 109 515 7949 McGilveray and Rinehart J Am Chem Soc 87 4003 1956]. 

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