Handbook of Solvents - George Wypych - ChemTech - Ventech!

812 Maw-Ling Wang
Figure 13.3.3. Effect of solvents on the conversion of
o-phenylene diamine in the two-phase catalyzed reaction;
3.17x10 -3 mol of C 6H 4(NH 2) 2, 2.50×10 -2 mol of
CS 2, 1.679×10 -3 mol of tributylamine (TBA), 1000
rpm, 30 o C. (Adapted from Ref. [128], by permission.)
Figure 13.3.5. Effect of solvents on the conversion of
o-phenylene diamine; 3.18x10 -3 mol of o-phenylene
diamine, 8 molar ratio of CS 2/C 6H 4(NH 2) 2,0.01Mof
triethylamine (TEA), and 50 mL of CH 3CN, 600 rpm,
40 o C. (Adapted from Ref. [130], by permission.)
Figure 13.3.4. Effect of solvents on the conversion of
o-phenylene diamine; 0.4 g of C 6H 4(NH 2) 2, 4.003 g of
CS 2, 0.4 mL of tributylamine (TBA), 50 mL of organic
solvent, 600 rpm, 30 o C. (Adapted from Ref. [129], by
permission.)
Several solvents, such as: n-decane, n-hexane,
benzene, chlorobenzene and dichloromethane,
which are immiscible with water,
were used. The effect of solvent on conversion
is shown in Figure 13.3.3. 128 The order
of the conversion of o-phenylene diamine
C 6H 4(NH 2) 2 in various organic solvents is:
dichloromethane > chlorobenzene > benzene
> n-hexane > n-decane, which is consistent
with the order of solvent polarity,
i.e., the greater the polarity of solvent the
higher the conversion of o-phenylene
diamine.
Results for the reaction of o-phenylene
diamine and carbon disulfide in a homogeneous
phase (organic solvent) are
given in Figure 13.3.4. 129 The order of the
reactivities is: dichloromethane (8.91) > chlorobenzene (5.6) > chloroform (4.8) > toluene
(2.4) > benzene (2.3). The reaction rate is related to the dielectric constant of the organic solvent.
A larger conversion of o-phenylene diamine was obtained using solvent with a higher
dielectric constant.
In choosing a polar organic solvent, such as: MeCN, MeOH, EtOH, DMSO, DMF and
THF, a homogeneous solution was used for the reaction. 130 Figure 13.3.5 shows the effects
of organic solvents (protic or aprotic) on the conversion of o-phenylene diamine. The order
of the reactivities for these six organic solvents is: DMF > DMSO > > MeCN > MeOH >
EtOH >THF. The corresponding dielectric constants of solvents are: DMF (37.71), DMSO
(46.45), MeCN (35.94), MeOH (32.66), EtOH (24.55) and THF (7.58), respectively. The
protic solvents, such as MeOH and EtOH, containing hydroxyl group possess acidic proper-