Ketones ethylmethyl

Part III extraction solvents that may be used for the preparation of flavourings from natural flavouring materials diethyl ether, hexane, methyl acetate, butan-l-ol, butan-2-ol, ethylmethyl ketone, dichloromethane,... 

Ethylmethyl Ketone Peroxide (Dimolekulares Me thy I a diy IketonsuperoiydjinGer), CH3XC2H5)OOCCCH,3XC2H5)6b mw 176.215... 

The mobile phase must be a solvent in which the sample dissolves well and must also be compatible with the stationary phase. For example, gStyragel columns must not come into contact with water, alcohols, acetone, ethylmethyl ketone or dimethyl sulfoxide. 

Condensation of 1 with acetone or ethylmethyl ketone in the presence of triethylamine afforded 2,2,4,7,7-pentamethyl- and 2,4-diethyl-2,7,7-trimethyl-5-oxo-2,6,7,8-tetrahydrobenzoIb]pyran 438 and 439, respectively [89IJC(B)81 ]. 

Ethyl acetale-ethylmethyl ketone-forinic acid-water (50 30 10 10)... 

Ethyl acetate-formic add-glacial acetic add-ethylmethyl ketone-water (50 7 3 30 10)... 

Abbreviations iPiOH—2-propanol, DX—dioxane, THF—tetrahydrofiiran, EtMeCo—ethylmethyl ketone, iPr20—diisopiopyl ether, DCM—dichloromethane. The eluent strength of polar modifier— n-heptane binary mixtures was selected to give retention factor k, of 1 for quinoline. 

First direction water-saturated ethylmethyl ketone... 

Food dyes permitted in Japan were investigated under fast atom bombardment (FAB) and liquid secondary ion (LSI) MS conditions with use of various materials. The mobile phase 10% Na2S04 solution-methanol-ethylmethyl ketone (7 2 2) was used for xanthenes and 10% Na2S04 solution-methanol-acetonitrile (10 3 3) for other dyes (102a). Seven permitted coloring materials used in foods and pharmaceutical preparations in Egypt were separated by two dimentional TLC on cellulose layers (102b). 

Eleven water-soluble dyes were separated by HPTLC on Si 60 gel with methylketone-methanol-aq. 28% NH3 (8 4.1) as the developing solvent. Dyes that were insoluble in aqueous concentrated NH3 were separated on layers of cellulose with butanol-ethylmethyl ketone-aq. 1% NH3-H2O (4 2 1 1) as developing solvent (142). The advantages of the method are shorter analysis time, more data measurement per plate, high resolution, and an improved signal-to-noise ratio compared with those of TLC plates. The theory of this technique is well discussed by Jupille et al. (143) along with some data on the separation of dyes. 

Thirteen dyes were separated by reversed phase TLC on C g modified silica gel using methanol-acetonitrile-aq. 5% Na2S04 (3 3 10) and then methanol-ethylmethyl ketone-aq. 5% Na2 SO4 (1 1 1) as mobile phases in same direction. Separation was optimum between pH 6.0 to 7.0 (145). Four basic dyes were separated on pretreated silica gel plates using HCIO4 or benzene sulphonic acid as counter ion and aqueous 50% or 60% ethanol as mobile phase (146). Polyacrylonitrile plates have been used for the separation of ten basic and common food dyes along with other dyes using diethylamine-anhy. acetic acid-H20 (4 1 15) as mobile phase (147). 

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