Dichloroethane data

The vapor is thea withdrawa from the stiH as distillate. The changing Hquid composition is most coavenieafly described by foUowiag the trajectory (or residue curve) of the overall composition of all the coexistiag Hquid phases. An exteasive amouat of valuable experimental data for the water—acetoae—chloroform mixture, including biaary and ternary LLE, VLE, and VLLE data, and both simple distillation and batch distillation residue curves are available (93,101). Experimentally determined simple distillation residue curves have also been reported for the heterogeneous system water—formic acid—1,2-dichloroethane (102). 

The chemistry of Lewis acid-base adducts (electron-pair donor-acceptor complexes) has stimulated the development of measures of the Lewis basicity of solvents. Jensen and Persson have reviewed these. Gutmann defined the donor number (DN) as the negative of the enthalpy change (in kcal moL ) for the interaction of an electron-pair donor with SbCls in a dilute solution in dichloroethane. DN has been widely used to correlate complexing data, but side reactions can lead to inaccurate DN values for some solvents. Maria and Gal measured the enthalpy change of this reaction... 

Using 1,2-dichloroethane as solvent, Brown et al. 16 have also studied the acetylation reaction, with acetyl chloride and aluminium chloride as reagents at 25 °C. The appropriate data for benzene are given in Table 111 and by comparison with Table 109 it appears that acetylation occurs some 300 times as fast as benzoylation. 

The greater steric hindrance to acetylation was also shown by a comparison of the rate of (103At2) of acetylation of toluene (0.763), ethylbenzene (0.660), i-propylbenzene (0.606) and f-butylbenzene (0.462) with those (determined by the competition method) for benzoylation both sets of data (Table 112) were obtained with dichloroethane as solvent at 25 °C, all reagent concentrations being 0.1 A/421. Relative rates of acylation other aromatics under the same conditions have also been obtained and are given in Table 113422. The different steric requirements for acetylation and benzoylation are further shown by the following respective relative rates for acylation of naphthalene derivatives in chloroform at 0 °C naphthalene (1 position) 1.00,1.00, (2 position) 0.31,0.04 2,3-dimethylnaphthalene (1 position) 1.59, 172, (5 position) 7.14, 38.2, (6 position) 3.68, 7.7422a. 

This approach allowed us also to determine the difference in the surface potentials between mutually saturated water and an organic solvent namely, nitrobenzene, nitroethane and 1,2-dichloroethane, and isobutyl methyl ketone (IBMK). The qualitative data show a very strong influence of the added organic solvent on the surface potential of water, while the presence of water in the nonaqueous phase has practically no... 

The ionic potentials can be experimentally determined either with the use of galvanic cells containing interfaces of the type in Scheme 7 or electroanalytically, using for instance, polarography, voltammetry, or chronopotentiometry. The values of and Aj f, obtained with the use of electrochemical methods for the water-1,2-dichloroethane, water-dichloromethane, water-acetophenone, water-methyl-isobutyl ketone, o-nitrotol-uene, and chloroform systems, and recently for 2-heptanone and 2-octanone [43] systems, have been published. These data are listed in many papers [1-10,14,37]. The most probable values for a few ions in water-nitrobenzene and water-1,2-dichloroethane systems are presented in Table 1. 

Girault and Schiffrin [6] and Samec et al. [39] used the pendant drop video-image method to measure the surface tension of the ideally polarized water-1,2-dichloroethane interface in the presence of KCl [6] or LiCl [39] in water and tetrabutylammonium tetraphenylborate in 1,2-dichloroethane. Electrocapillary curves of a shape resembling that for the water-nitrobenzene interface were obtained, but a detailed analysis of the surface tension data was not undertaken. An independent measurement of the zero-charge potential difference by the streaming-jet electrode technique [40] in the same system provided the value identical with the potential of the electrocapillary maximum. On the basis of the standard potential difference of —0.225 V for the tetrabutylammonium ion transfer, the zero-charge potential difference was estimated as equal to 8 10 mV [41]. 

Table 4.2 UV/visible spectral data (Xmax values in nm) for solutions of some symmetrical di-substituted indigo derivatives 57 and 57a-d in 1,2-dichloroethane.

Figure 12.4 Capacity of the interface between aqueous solutions containing alkali halides and a solution of TPAs/TPB in 1,2-dichloroethane. The electrolyte concentration in both cells was 10 2 M. Alkali halides used (a) CsCl, (b) RbCl, (c) KC1, (d) NaCl, (e) LiCl. Data taken from Ref. 5.

So far only a few quantitative data on the thermodynamic stability of arenediazonium salts and crown ethers have been reported. Bartsch et al. (1976) calculated the value of the association constant of the complex of 18-crown-6 and 4-t-butylbenzenediazonium tetrafluoroborate from kinetic data on the thermal decomposition of the complex, Kt = 1.56 x 105 1 mol-1 in 1,2-dichloroethane at 50°C. Compared with the corresponding linear polyether this is at least a factor of 30 higher (Bartsch and Juri, 1979). 

The thermal decomposition of arenediazonium tetrafluoroborates is slowed down when the salt is complexed by 18-crown-6 (Bartsch et al., 1976). The kinetic data obtained for the 4-t-butylbenzenediazonium salt at 50°C in 1,2-dichloroethane revealed that the rate of complexed to uncomplexed salt is more than 100. Other crown ethers such as dibenzo-18-crown-6 and dicyclohexyl-18-crown-6 exhibited the same effect but smaller molecules such as 15-crown-5 did not influence the rate at all. It is not only the rate of the Schiemann reaction that is affected by the crown ether nucleophilic aromatic substitutions by halide ions (Cl-, Br-) at the 4-positions in arenediazonium salts are retarded or even entirely inhibited when 18-crown-6 is added. This is attributed to the attenuation of the positive charge at the diazonio group in the complex (Gokel et al., 1977). 

Synthesis of natural-type aminopolysaccharide having dibenzylchitin structure was achieved by the polymerization of a sugar oxazoline monomer, 1 having one hydroxy group at position 4 (Scheme 4) [9]. The polymerization was carried out with an acid catalyst in 1,2-dichloroethane solvent at reflux temperature. All the H-NMR, C-NMR, and IR spectra as well as elemental analysis data of the isolated polysaccharide supported that the polymerization proceeded by the stereoregular glycosylation to give (1 4)-... 

Mussari, L., Postigo, M., Lafuente, C., Royo, F.M., and Urieta, J.S. Viscosity measurements for the binary mixtures of 1,2-dichloroethane or 1,2-dibromoethane with isomeric butanols. J. Chem. Eng. Data, 45(1) 86-91, 2000. 

Table 5-1 shows the various kinetic parameters, including k+ and kp, in the polymerization of styrene initiated by triflic acid in 1,2-dichloroethane at 20°C. Data for the polymerization of isobutyl vinyl ether initiated by trityl hexachloroantimonate in methylene chloride at 0°C are shown in Table 5-2. Table 5-3 shows values for several polymerizations initiated... 

The data in Table 6-11 show the copolymer composition to be insensitive to the initiator for solvents of high polarity (1,2-dichloroethane and nitrobenzene) and also insensitive to solvent polarity for any initiator except the strongest (SbCl5). The styrene content of the copolymer decreases with increasing solvent polarity when SbCl5 is the initiator. The styrene content also decreases with decreasing initiator strength for the low-polarity solvent... 

The thermodynamic data of Tables 2 and 3 are remarkably selfconsistent, and correlate well with data for the various phenyltrimethyl ammonium perchlorates in 1,2-dichloroethane originally studied by Denison and Ramsey (44). Clearly dissociation is nominally exothermic though the actual enthalpy changes are quite small. Solvation of the free ions, therefore, is also small (in these solvents) but exceeds that of the ion pair species. The overall entropy changes confirm some ordering of solvent molecules on dissociation, the loss in entropy for this process being more than sufficient to balance the entropy increase associated with... 

A similar lack of dependence on substituent chain length has been reported previously for aqueous solutions of similar salts (66). Dissociation constants of a number of cetyl ammonium picrates and nitrates in 1,2-dichloroethane ( 2 x 10 4—0.5 x 10"4 M) are also in remarkably close agreement with the data of Table 5. 

The unusually high observed initial intrinsic viscosity was at first thought to be due to molecular aggregation of polymer chains, made possible by presumed interaction of the carboxyl ester groups. Molecular association is known in many polymeric systems, but in those cases the association process is also apparent in osmometric data. No evidence of association is observed in the osmometric data of poly[(a-carboxymethyl)ethyl isocyanide]. Moreover, it would be expected that, if molecular association would have taken place, different values of [>7] would have been observed upon changing of solvents. Such change is not observed upon addition of triethyl amine (i.e. 10% volume) to 1,2-dichloroethane, or by solvent change to p-dioxane. 

---