Table 1.

Overview of the used hydrolysates. Furfural and 5‐hydroxy‐methylfurfural were determined with HPLC, vanillin with GC‐TOF‐MS.

Source material	Pre‐treatment	Furfural (mM)	Vanillin (mM)	5‐hydroxy‐methylfurfural (mM)	Provider/reference
Own analysis:
Wheat straw I	Acid STEX	5.0	0.6	1.4	Institut Français du Pétrole, SAF‐ISIS
Wheat straw II	Acid STEX	7.1	0.8	2.2	Institut Français du Pétrole, SAF‐ISIS
Spruce	Acid steam	11.5	1.0	17.0	Guido Zacchi
Barley straw	Acid steam	30.0	0.7	7.9	Guido Zacchi
Literature:
Spruce	Dilute acid (one/two step)	5.2/10.4	0.8	15/46	Larsson et al. (1999); Nilvebrant et al. (2003)
Corn stover	Steam	115	N/I	0.5	Öhgren et al. (2006)
Wheat straw	Wet oxidation	N/I	0.2	N/I	Klinke et al. (2003)
Willow	Acid steam	N/I	2.7	N/I	Jönsson et al. (1998)
Sugar cane	Steam	20.0	N/I	4.8	Martin et al. (2001)
Poplar	Dilute acid	N/I	0.10	N/I	Fenske et al. (1998)
Switchgrass	Dilute acid	N/I	0.10	N/I	Fenske et al. (1998)
Corn stover	Dilute acid	N/I	0.12	N/I	Fenske et al. (1998)

N/I, not identified; STEX, steam explosion.