Table 4.
Summary of selected metal‐based and organocatalysts reported for the hydrogenation and hydrosilylation of PET.
|
Cataylst |
Cat. [mol %] |
Solvent |
T [°C] |
H2 [bar] |
t [h] |
PET conv. [%] |
Product(s) |
Yield[a] [%] |
Ref. |
|---|---|---|---|---|---|---|---|---|---|
|
Hydrogenation |
|
|
|
|
|
|
|
|
|
|
ruthenium(II)‐PNN pincer |
2[b] |
anisole/THF |
160 |
54.4 |
24 |
100 |
1,4‐benzenedimethanol; EG |
>99 |
[156] |
|
RuII‐triphos complex (R=xyl) |
0.2[c] |
1,4‐dioxane |
140 |
100 |
16 |
100 |
1,4‐benzenedimethanol; EG |
>99 |
[157] |
|
RuII‐sulfoxide complex |
2[d] |
anisole/THF |
110 |
50 |
48 |
– |
1,4‐benzenedimethanol; EG |
73 |
[277] |
|
C/MoO2 |
2.5 |
– |
260 |
1.0 |
24 |
– |
TA; EG; trace acetaldehydes |
87; 87; <5 |
[279] |
|
Hydrosilylation |
|
|
|
Silane (equiv.) |
|
|
|
|
|
|
B(C6F5)3 |
2 |
CH2Cl2 |
25 |
Et3SiH (4.3) |
3 |
– |
Si‐1,4benzenedimethanol; Si‐EG |
85; 72[e] |
[161] |
|
5 |
CH2Cl2 |
25 |
TMDS (6.0) |
16 |
– |
p‐xylene; ethane |
82; –[f] |
[161] |
|
|
7.5 |
CH2Cl2 |
25 |
PMHS (11.0) |
16 |
– |
p‐xylene; ethane |
75; –[f] |
[161] |
|
|
Brookhart's iridium(III) catalyst |
1 |
chlorobenzene |
70 |
Et3SiH (6.0) |
72 |
– |
Si‐1,4benzenedimethanol; Si‐EG |
63; 48[e] |
[162] |
|
MoO2Cl2(H2O)2 |
5 |
chlorobenzene |
160 |
PhSiH3 (6.0) |
96 |
– |
p‐xylene; EG |
65 |
[163] |
[a] Product yields refer to 1H NMR analysis unless otherwise stated. [b] KOtBu employed as a co‐catalyst in a loading ratio of 50 : 1 : 2 {[ester repeat unit]/[catalyst precursor]/[KOtBu]}. [c] HNTf2 employed as a co‐catalyst in a loading ratio of 500 : 1 : 5 {[ester repeat unit]/[catalyst precursor]/[HNTf2]}. [d] KOtBu employed as a co‐catalyst in a loading ratio of 50 : 1 : 20 {[ester repeat unit]/[catalyst precursor]/[KOtBu]}. [e] Isolated yield. [f] p‐Xylene yield obtained by GC‐MS analysis. Ethane yield not determinable by 1H NMR spectroscopy owing to insolubility of PET in CH2Cl2.