Table 2. Catalytic activity in the decomposition of formaldehyde/water mixtures by Ru complexes*.
| |||||
---|---|---|---|---|---|
Entry | Catalyst | KOH (equivalents) | TOF50 (h−1)† | Total yield H2 (%)‡ | TONmax/duration§ |
1 | 1K | — | — | 23 | 115/12 h |
2|| | 1K | 2 | 8,109 | 56 | 280/12 h |
3|| | 1K | 6 | 17,500 (first load) | 86 | 430/2 h |
4 | 1K | — (second load) | 12 | 103/2 h | |
5|| | 1Aa | 6 | 15,101 (first load) | 90 | 450/12 min |
6¶ | 1Aa | 6 | 12,000 (sixth load) | 59 | 1,787/20 min |
7|| | 1Ab | 6 | 13,520 | 81 | 405/15 min |
8|| | 4 | 6 | 17,000 | 90 | 450/2 h |
9 | 5H2 | 6 | 6,000 | 68 | 340/4 h |
10|| | 5 | 6 | 7,500 | 75 | 375/4 h |
11|| | 3a | 4 | 3,537 | 58 | 290/4 h |
12|| | 6 | 4 | 750 | 69.5 | 347/4 h |
13|| | 7 | 4 | 4,091 | 65 | 325/4 h |
14# | 1Aa | 6 | 29,764 (first load) | 90 | 450/15 min |
15** | 1Aa | 6 | 22,000 (second load) | 85 | 765/15 min |
16†† | 1Aa | 6 | 805 | 92 | 460/2 h |
17‡‡ | 1Aa | 6 | — | <5 | —/12 h |
*Reaction conditions: formaldehyde (1.0 mmol) c0=0.47 M, 0.4 mol% [Ru] at 60 °C in water/THF (10:1).
†TOF values after 50% conversion (1 equivalents H2 released per formaldehyde unit).
‡Yield considering 2 equivalents H2/equivalent HCOH.
§TON=mmol H2released per mmol [Ru].
||Values are an average of three catalytic runs.
¶Final value after the sixth addition of HCOH aq. to the reaction mixture of entry 5.
#Paraformaldehyde (1.0 mmol) c0=0.47 M, 0.4 mol% [Ru] at 60 °C in water/THF (10:1).
**Final value after the second addition of HCOH to the reaction mixture of entry 14. Average of three runs.
††Same conditions as in entry 14 under CO(g) atmosphere. Average of three runs.
‡‡Same conditions as in entry 16 under air. Average of two runs.