260
S. Chatterjee et al.
source, 500 W) was provided instead of FIR. The traditional AFEX pretreatment
was modified by employing FIRR. In a representative hydrolysis run, a measured
amount of PWPS and Amberlyst 15 (Table 2) were initially loaded in the IRRBR
reactor followed by addition of distilled water (taken as the zero time) at fixed water
to PWPS ratio (35 w/w, pH = 6.7). After the specified time, the reaction mix was
filtrered to separate the solid catalyst and PWPS residue. Additionally, the yield of RS
(mol%) was evaluated according to Girisuta et al. (2013). The concentration of each
compound in hydrolysis product was determined through calibration curves prepared
by analyzing standard solutions of respective compounds of known concentrations.
The superiority of IRRBR over TBR in the hydrolysis of PWPS was evaluated by
comparing the RS concentration obtained in TBR at the TOEM derived optimal
process conditions. Furthermore, hydrolysis of PWPS was conducted in absence of
Amberlyst 15 using IRRBR and TBR at the optimal conditions. The resulting RS
yields were analyzed and compared with that of the catalytic hydrolysis to study the
effects of the catalyst on the PWPS hydrolysis.
3 Results and Discussion
3.1 TOEM Analysis
The design of hydrolysis experiments as per TOEM and mean of three experimental
values of Φ g along with the computed S/N ratio (Eq. 1) are presented in Table 2.
Summary results of the ANOVA ( Table 3) indicate that the p values of X T and
X t are significant (P < 0.05) among the other process parameters.
Table 2 L9 orthogonal experimental matrix at different operating conditions and corresponding
mean Φ g and signal-to-noise (S/N) ratio
Trial No X pc (w/w) X T (°C) X wp (w/w) X t (min) Φ g (mol/mol) S/N ratio(dB)
1
L 1
L 1
L 1
L 1
75.67 ± 0.12
37.58
2
L 1
L 2
L 2
L 2
84.19 ± 0.23
38.50
3
L 1
L 3
L 3
L 3
79.51 ± 0.14
38.01
4
L 2
L 1
L 2
L 3
73.84 ± 0.21
37.37
5
L 2
L 2
L 3
L 1
86.78 ± 0.19
38.77
6
L 2
L 3
L 1
L 2
82.23 ± 0.22
38.30
7
L 3
L 1
L 3
L 2
74.87 ± 0.34
37.49
8
L 3
L 2
L 1
L 3
81.68 ± 0.13
38.24
9
L 3
L 3
L 2
L 1
80.27 ± 0.41
38.09
S. Chatterjee et al.
source, 500 W) was provided instead of FIR. The traditional AFEX pretreatment
was modified by employing FIRR. In a representative hydrolysis run, a measured
amount of PWPS and Amberlyst 15 (Table 2) were initially loaded in the IRRBR
reactor followed by addition of distilled water (taken as the zero time) at fixed water
to PWPS ratio (35 w/w, pH = 6.7). After the specified time, the reaction mix was
filtrered to separate the solid catalyst and PWPS residue. Additionally, the yield of RS
(mol%) was evaluated according to Girisuta et al. (2013). The concentration of each
compound in hydrolysis product was determined through calibration curves prepared
by analyzing standard solutions of respective compounds of known concentrations.
The superiority of IRRBR over TBR in the hydrolysis of PWPS was evaluated by
comparing the RS concentration obtained in TBR at the TOEM derived optimal
process conditions. Furthermore, hydrolysis of PWPS was conducted in absence of
Amberlyst 15 using IRRBR and TBR at the optimal conditions. The resulting RS
yields were analyzed and compared with that of the catalytic hydrolysis to study the
effects of the catalyst on the PWPS hydrolysis.
3 Results and Discussion
3.1 TOEM Analysis
The design of hydrolysis experiments as per TOEM and mean of three experimental
values of Φ g along with the computed S/N ratio (Eq. 1) are presented in Table 2.
Summary results of the ANOVA ( Table 3) indicate that the p values of X T and
X t are significant (P < 0.05) among the other process parameters.
Table 2 L9 orthogonal experimental matrix at different operating conditions and corresponding
mean Φ g and signal-to-noise (S/N) ratio
Trial No X pc (w/w) X T (°C) X wp (w/w) X t (min) Φ g (mol/mol) S/N ratio(dB)
1
L 1
L 1
L 1
L 1
75.67 ± 0.12
37.58
2
L 1
L 2
L 2
L 2
84.19 ± 0.23
38.50
3
L 1
L 3
L 3
L 3
79.51 ± 0.14
38.01
4
L 2
L 1
L 2
L 3
73.84 ± 0.21
37.37
5
L 2
L 2
L 3
L 1
86.78 ± 0.19
38.77
6
L 2
L 3
L 1
L 2
82.23 ± 0.22
38.30
7
L 3
L 1
L 3
L 2
74.87 ± 0.34
37.49
8
L 3
L 2
L 1
L 3
81.68 ± 0.13
38.24
9
L 3
L 3
L 2
L 1
80.27 ± 0.41
38.09