Table 1.
Polymerization of lactides promoted by 1.[a]
|
Run |
Monomer |
[LA]/[Zn]/[ROH] |
t [min] |
T [°C] |
Conv. [%] |
TOF [h−1] |
M nGPC [b] [kDa] |
Ð [b] |
M nth [c] [kDa] |
|---|---|---|---|---|---|---|---|---|---|
|
1 |
rac‐LA |
100 : 1 : 0 |
8 |
25 |
61 |
457 |
2.7 |
1.70 |
8.8 |
|
2 |
rac‐LA |
100 : 1 : 1 |
1 |
25 |
100 |
2640[g] |
13.0 |
1.07 |
14.4 |
|
3 |
rac‐LA |
400 : 1 : 1 |
1 |
25 |
77 |
28320[g] |
49.5 |
1.14 |
44.4 |
|
4 |
l‐LA |
400 : 1 : 1 |
1 |
25 |
70 |
25920[g] |
45.1 |
1.12 |
40.3 |
|
5 |
l‐LA |
400 : 1 : 40 |
2 |
25 |
97 |
14880[g] |
1.80 |
1.10 |
1.44 |
|
6 |
l‐LA |
400 : 1 : 100 |
2 |
25 |
67 |
8040 |
0.9 |
1.10 |
0.4 |
|
7[d] |
l‐LA |
1000 : 1 : 2 |
2 |
25 |
56 |
16800 |
37.8 |
1.30 |
40.3 |
|
8[e] |
l‐LA |
1000 : 1 : 2 |
2 |
25 |
68 |
20400 |
31.2 |
1.37 |
48.9 |
|
9[f] |
l‐LA |
1000 : 1 : 0 |
4 |
150 |
23 |
3450 |
46.9; 28.2 |
bimodal |
33.2 |
|
10[f] |
l‐LA |
1000 : 1 : 10 |
1 |
150 |
100 |
60000 |
9.7 |
1.38 |
14.4 |
|
11[f] |
l‐LA |
1000 : 1 : 50 |
0.5 |
150 |
100 |
120000 |
3.1 |
1.91 |
2.9 |
|
12[f] |
l‐LA |
5000 : 1 : 50 |
5 |
150 |
82 |
49200 |
8.9 |
1.44 |
11.5 |
[a] All reactions were carried out by using 10 μmol of Zn catalyst at 25 °C in CH2Cl2 (2 mL), ROH was iPrOH for runs at 25 °C and BnOH for runs at 150 °C. [b] Experimental M n (corrected using factor of 0.58) and Ð values were determined by gel‐permeation chromatography (GPC) in THF using polystyrene standards. [c] Calculated M nth=144.14×([LA]/[ROH])×conv. of LA. [d] LA purified by a single crystallization. [e] Unpurified LA. [f] Technical‐grade purity LA, solvent free. [g] TOF calculated after 0.5 min, conversions reported in Table S1.