Standard solvents mixture

The printing ink industry uses P.Br.25 for all printing methods. The prints show excellent lightfastness. 1/1 to 1/25 SD letterpress proof prints, for instance, equal step 7 to step 6-7 on the Blue Scale. Prints made from P.Br.25 are fast to the DIN 16 524 standard solvent mixture, to paraffin, butter, soap, and acid, but they are not entirely fast to alkali. The products are fast to clear lacquer coatings and may safely be sterilized. The temperature stability is up to 240°C for 10 minutes or 220°C for up to 30 minutes, which makes P.Br.25 a suitable candidate for metal deco printing inks. It is also frequently applied in printing inks for PVC. 

The printing ink industry applies P.Y.110 in all types of printing, provided the pigment satisfies the demands. The prints are resistant to many organic solvents, including the DIN 165224/1 standardized solvent mixture. Prints made from P.Y.l 10 are fast to clear lacquer coatings, sterilization, and are very heat stable. 1/1 to 1/25 SD letterpress proof prints equal step 7 on the Blue Scale for lightfastness. 

The distribution of solutes between the two phases can be estimated by measurement of the relative solubility of the reagent in each phase of the system under given physical conditions. Water and 1-octanol have become a standard solvent mixture for this [21], although other pairs of solvents may be used to produce, for example, a scale of preference for fluorous versus organic solvents, as described below. The quantity P, known as the partition coefficient, is defined as... 

The best tic solvent system for a particular compound or mixture can only be determined by trial and error. However it is good practice to stick to a standard solvent mixture, which can be used most of the time and which you are familiar with. The most widely used solvent mixtures are based on a non-polar hydrocarbon, such as 40/60 petroleum ether or hexane, with a polar constituent added in a proportion which gives a suitable polarity. Probably the most popular universal tic system is petroleum ether - ethyl acetate, the polarity of which is easily adjusted by changing the proportions of the two solvents. If the compounds being analyzed will not travel in ethyl acetate mixtures, a more polar solvent such as ethanol is used as the additive. On the other hand, if the compounds travel too far a less polar additive such as petroleum ether is used. 

The Crismer value (CV) measures the miscibility of an oil in a standard solvent mixture, composed of f-amyl alcohol, ethyl alcohol, and water in volume proportion 5 5 0.27 (Table 13). This parameter is one of the specification criteria used for international trade, mostly in Europe however, today it is rarely used. The values obtained are characteristic within a narrow limit for each kind of oil. The miscibility of oil is related to the solubility of acylglycerols and is affected mainly by the unsaturation and chain length of the constituent fatty acids. 

Fig. I Fluorescence scan of (A) a blank track and (B) a standard gentamycin mixture (800 ng C complex per applieation). Start (1), gentamyein Cj, (2), C2IC2 , (3), Ci (4), solvent front...

A plot depicting isokinetic relationships, (a) The thermal rearrangement of triarylmethyl azides, reaction (7-35) is shown with different substituents and solvent mixtures. The slope of the line gives an isokinetic temperature of 489 K. Data are from Ref. 8. (b) The complexation of Nr by the pentaammineoxalatocobalt(III) ion in water-methanol solvent mixtures follows an isokinetic relationship with an isokinetic temperature of 331 K. The results for forward (upper) and reverse reactions are shown with the reported standard deviations. Data are from Ref. 9. 

In our previous studies on chlorination of toluene we had found that solvent had an important effect on the selectivity. In particular, the use of diethyl ether as a cosolvent was advantageous for the production of a high proportion of the para-isomer (ref. 9). An experiment in which the amount of ether in a tetrachloromethane/diethyl ether solvent mixture was varied under otherwise identical reaction conditions (Ih reaction at 18°C with 1.04 molar equivalent of tert-butyl hypobromite) demonstrated that diethyl ether also had a marked influence on the selectivity of the bromination reaction (Fig. 6). There was also an effect on the yield of the reaction as performed under these standard conditions. As the... 

One of the most complex separation schemes utilizes flash liquid chromatography and PLC to obtain petropophyrins both from geochemical samples or those synthesized and used subsequently as standards [110]. Ocampo and Repeta [111] described the scheme of petroporphyrins isolation in which at the first step the sediment extract is fractionated into ten fractions on silica gel using dichlo-romethane (fractions 1 to 4), a mixture of dichloromethane-acetone with increasing acetone concentrations (for fractions 5 to 9), and, at last, dichlo-romethane methanol (4 1) (fraction 10). Next, the fifth fraction was separated on silica PLC plates using dichloromethane-acetone (97.5 2.5 v v v) as a developer. Two purple bands (with Rj 0.53 and 0.50) were recovered from silica and purified further on a silica gel column with dichloromethane-acetone (97.5 2.5, v v v) as an eluent. The emiched fraction was then separated by PLC with the same solvent mixture, and the purple bands containing two bacteriopheophytin allomers were recovered with acetone. 

In separate 25-mL graduated cylinders, add 16 mL of the 4 N HCl-methanol solvent mixture (10 3) and the quantities of the EMA/HEMA standard solution in methanol given in Table 2. 

Residues of isoxaflutole, RPA 202248 and RPA 203328 are extracted from surface water or groundwater on to an RP-102 resin solid-phase extraction (SPE) cartridge, then eluted with an acetonitrile-methanol solvent mixture. Residues are determined by liquid chromatography/tandem mass spectrometry (LC/MS/MS) on a Cg column. Quantitation of results is based on a comparison of the ratio of analyte response to isotopically labeled internal standard response versus analyte response to internal standard response for calibration standards. 

A number of potential users, such as the printing industry, are interested in the solvent fastness not only of a pigment but of an entire pigment-vehicle system. Standardized tests are available. A proof print of a certain size is placed inside a test tube and allowed to remain in the target solvent at 20°C for 5 minutes. The change in solvent color is determined and the print dried and compared with an untreated specimen. Standard solvents [14] are ethanol or the following mixture ... 

P.Y.l 16 generally exhibits good fastness properties in printing inks. In letter-press and offset application, for instance, it resists a number of organic solvents, such as the standard DIN 16524/1 solvent mixture (Sec. 1.6.2.1), paraffins, butter,... 

P.Y.114 is primarily supplied to the printing ink industry, where it is used especially for packaging inks. The pigment is utilized to produce prints at reasonable cost, especially where exceptional fastness, as provided by P.Y.83, is a minor consideration. Prints made from P.Y.114 are not entirely resistant to a number of organic solvents, including the standard DIN 16 524 solvent mixture, paraffin, and butter but P.Y.114 prints are soap, alkali, and acid resistant. The fact that the pigment does not withstand a temperature of 140°C and is not stable to sterilization excludes P.Y.114 from use in metal deco printing. 

Prints containing Alkali Blue are not fast to the standard DIN 16524 solvent mixture, but they are fast to acid, paraffin, butter, and other materials. Tested in accordance with normative testing standards (Sec. 1.6.2.2), the prints unexpectedly also show fastness to alkali. It should be noted, however, that at higher alkali concentrations the tinctorial strength of the system declines and the shade becomes duller. This is a result of the fact that the pigment reacts with alkali. 

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