PaMS+toluene

Electrophile Benzene Toluene Ortho Xylene Meta Pam... 

Equation (a) Toluene-pam-sulphonamide on dissolution in an excess of sodium hypochlorite solution gives rise to the formation of toluene-p-sulphon-chloro-sodio-amide (I), which being water-soluble does not ordinarily crystallise out unless and until very concentrated solutions are employed. 

Cg-M was polymerized by two different methods in order to obtain two different molecular weights. As shown in Table 2, the sample Cg-PAM-M obtained from an equilibrium polymerization in HMPA/NMP mixture without removing the formed water gave distinctively smaller value than Cg-PAM-T obtained from polymerization under continuous removal of the water. Table 2 shows also that C,2-PAM-T has particularly smaller rij value than other PAM-T samples albeit polymerized in toluene. This suggests that the dodecoxymethyl side chain is so long that it exerts a steric hinderance toward approach of p-phenylene diamine. 

Polyazomethines without any side branches are known to be only slightly soluble in concentrated sulfuric or methanesulfonic acid and totally insoluble in any common organic solvents. As to see from Table 2, solubility of the C -PAMs is increased in several specified solvents. Particularly in w-cresol they are freely soluble. However, when we compare the solubility of Cg-PAM-T and that of Cg-PAM-M, the latter is better soluble in chloroform, toluene, THF or HMPA than the former. These two PAMs have the same side chain length, but different molecular weight. Therefore it can be said that solubility of C -PAMs is influenced not only by attachment of a side branch but also by molecular weight. The remarkable solubility enhancement of C -PAMs relative to PAMs without any side branch results from the interaction between the side branch and the rigid backbone. 

FIGURE 1.5 Double-logarithmic plots of against a o, a-Pa MS in toluene at 25.0°C , data for a-PaMS in 4-tert-butyltoluene at 25.0°C o, data for a-PaMS in n-butyl chloride at 25.0°C , a-PS in toluene at 15.0°C A, a-PMMA in acetone at 25.0°C 13 T, i-PMMA in acetone at 25.0°C. The solid curve represents the QTP theory values calculated from Eq. (1.11) with Eq. (1.14) (see the text). (From Tominaga et al. [2002b], with permission. Copyright 1993 American Chemical Society.)... 

Figure 5.20 shows the dependence of nf(CpkT) vs X in comparison with experimental results obtained using a PaMS solution in toluene at 25 C (Noda et aJ., 1981). For this comparison, Ohta and Oono (1982) have, adjusted a proportionality constant between X and Cp/c, where c is the cx)il overlap concentration. A study was made (Noda et al., 1981) on polymer samples with a narrow MWD. The agreement between the experimental values of n and the curve of a monomolccular polymer is very good except for large values of X, which is explmned by the authors by the first order of approximation in this version of theory. 

Methanol is first activated in the zeolite to form the CH3 + intermediate as was described in Section 4.2.1. The CH3 + intermediate subsequently adds to the para position on the adsorbed toluene to form pam-xylene. The CH3 + intermediate can similarly attack the adsorbed toluene at the ortho and meta positions to give ortho- and meia-xylene, respectively. 

Dendrimers have been studied by low dose electron microscopy, using samples prepared by deposition of a dilute solution of the PAM family of molecules (based on a cyclic phenyl-acetylene backbone) in toluene onto amorphous carbon coated mica sheets [25]. Once the solvent is dried, the carbon film and crystallite layer were floated off the mica substrate and collected on copper grids gold was evaporated on the samples as a calibration standard for electron microscopy. 

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