Acetone liquid temperature range

The choice of a solvent for a particular reaction will usually depend on more than one variable. These include the liquid temperature range, the dielectric constant, and whether or not the solvent is reactive in the chemical reaction. The most important consideration in the latter context is often the presence of an easily transferred proton. Certain solvents, such as acetone, are considered aprotic but may transfer a proton under basic conditions. Thus the designations given below are general and approximate. They are intended to guide the reader to the more detailed information contained in the full tables. 

Generally, specimens are frozen by direct immersion of the vessel into a cooling bath, which consists of either liquid nitrogen, dry ice-acetone, dry ice-alcohol, or any other media previously cooled to the appropriate temperature range. The specimen can also be frozen in a deep freezer. It is noteworthy that the spontaneous... 

Again the acetone conversions are essentially quantitative over the full temperature range considered (see column three. Table 2, for the typical temperatures in each of the three catalyst zones). However in this case, it is noteworthy that the IPA + DIPE molar selectivities exceed 98% and we are able to minimize the coproduction of C-3 gas, as well as C-6/C-9 condensation products (DIPE to C-3/-6/-9 wt ratio >30). Consequently, DIPE effluent concentrations reach ca. 38% when the catalyst temperature sequence is 104-159-146"C. Liquid recoveries in this experimental series were again essentially quantitative. 

Gamma-butyralactane is a powerful solvent and undergoes many reactions that make it of considerable interest in synthesis. It is a colorless hygroscopic liquid aver a wide temperature range. It is soluble in acetone, benzene, carbon tetrachloride, ethyl ether, methanol, monochlorobenrene and water in all proportions. 

Besides the pure component parameters, in particular the mixture parameters, for example of a g -model or an equation of state, should be checked carefully prior to process simulation. The procedure is shown in Figure 11.4 for the binary system acetone-cyclohexane, which may be one of the binary key systems of a multicomponent mixture. From the results shown in Figure 11.4, it can be concluded that the VLE behavior of the binary system can be reliably described in the temperature range 0-50 C with the Wilson parameters used. But from the poor -results, it seems that an extrapolation to higher or lower temperature may be dangerous, as already can be seen from the solid-liquid equilibrium (SLE) results of the eutectic system in the temperature range 0 to —lOO C and also from the incorrect temperature dependence of the calculated azeotropic data. 

Chromatograms of n-pentane on Carbopack C with acetone (modifier) in the carrier gas over a wide temperature range are shown in Fig. 5-30 [76]. The main effect of acetone dopant consisted in diminishing the retention time of penteine at low temperatures. Thus the eluted peaks were sharper at the lowest temperature than at intermediate temperatures (30-40 °C). This effect is illustrated in Fig. 5-30 [76]. The loss of available adsorbent surface due to the preferential adsorption of acetone caused rapid elution of pentane and significant decrease of the peak width. Carbopack adsorbents are known to be very useful for polar sample separation. However, they must be deactivated with a small amount of a non-volatile liquid. Non-deactivated adsorbents are not suitable for polar solutes. As an example. Fig. 5-31 [76] illustrates... 

Aqueous solutions are not suitable solvents for esterifications and transesterifications, and these reactions are carried out in organic solvents of low polarity [9-12]. However, enzymes are surrounded by a hydration shell or bound water that is required for the retention of structure and catalytic activity [13]. Polar hydrophilic solvents such as DMF, DMSO, acetone, and alcohols (log P<0, where P is the partition coefficient between octanol and water) are incompatible and lead to rapid denaturation. Common solvents for esterifications and transesterifications include alkanes (hexane/log P=3.5), aromatics (toluene/2.5, benzene/2), haloalkanes (CHCI3/2, CH2CI2/I.4), and ethers (diisopropyl ether/1.9, terf-butylmethyl ether/ 0.94, diethyl ether/0.85). Exceptionally stable enzymes such as Candida antarctica lipase B (CAL-B) have been used in more polar solvents (tetrahydrofuran/0.49, acetonitrile/—0.33). Room-temperature ionic liquids [14—17] and supercritical fluids [18] are also good media for a wide range of biotransformations. 

The first literature report of a reaction of an isocyanate with wood is that due to Clermont and Bender (1957). In this study, DMF impregnated wood samples 1/8 in thick were suspended above phenylisocyanate liquid in a vessel heated at temperatures from 100 °C to 125 °C for various time intervals. Treated samples were washed with DMF, then water, then acetone, and dried in an oven at 105 °C. ASEs in the range of 60-80 % were reported for these samples. In view of the reactivity of DMF with isocyanates, the lack of an efficient clean-up procedure and the fact that ASE values were calculated from the first water-soak cycle only, this study is of limited value. 

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