10.1002/cctc.201200482
Catalytic Performance of Zeolite-Supported Vanadia in the Aerobic Oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran
5-Hydroxymethylfurfural (HMF; >99 %), acetonitrile (>=99.9 %), toluene (anhydrous, 99.8 %), α,α,α-trifluorotoluene (TFT) (>=99 %), N,N-dimethylformamide (DMF; >=99.9 %), ammonium metavanadate (>=99 %), oxalic acid (>=99 %), sodium nitrate (>=99 %), and anisole (99 %) were acquired from Sigma-Aldrich. Methyl isobutyl ketone (MIBK; > 2,5-Diformylfuran (DFF; 98 %) was supplied by ABCR GmbH & Co. Dioxygen (99.5 %) was purchased from Air Liquide, Denmark. All NH4-zeolites were obtained from Zeolyst International, USA. Vanadium oxide (99.8 %) was acquired from Chr. Gerner-Jensen. All chemicals were used as received. 

Commercial NH4-ZSM-5 (Si/Al=15), NH4-beta (Si/Al=25), NH4-mordenite (Si/Al=10) and NH4-Y (Si/Al=12) zeolites were initially calcined at 550 degC for 5 h to obtain the H-ZSM-5, H-beta, H-mordenite, and H-Y supports, respectively. 

Vanadia supported on zeolite catalysts with 1-10 wt % V2O5 were prepared by wet impregnation of the supports with vanadium oxalate solution, by a procedure adopted from the literature.44 In a typical experiment to prepare 3 wt % zeolite-supported vanadia catalyst, 1.75 mL of NH4VO3/oxalic acid aqueous solution (0.378 M, prepared from ammonium metavanadate and oxalic acid in the molar ratio 1:2 at 70 degC) was added to 1 g of the zeolite using an incipient wetness impregnation technique. Once the impregnation was completed, the solids were dried at 120 degC for 8 h and then calcined at 500 degC for 5 h. The catalysts were named according to the nominal V2O5 loading in wt % and the support. 

For the preparation of the Na-beta support, 10 g of NH4-beta were suspended in 300 mL of 1 M aqueous solution of NaNO3. The mixture was heated to 80 degC and stirred for 1 hour. Afterwards, the zeolite was filtered and washed with distilled water. This procedure was repeated twice. Finally, the recovered Na-beta material was dried and then calcined at 500 degC for 5 h.

2,5-diformylfuran
5-Hydroxymethylfurfural (HMF
>99 %
%
acetonitrile
>=99.9 %
%
toluene
anhydrous
99.8 %
%
α,α,α-trifluorotoluene (TFT)
>=99 %
%
N,N-dimethylformamide (DMF
>=99.9 %
%
ammonium metavanadate
>=99 %
%
oxalic acid
>=99 %
%
sodium nitrate
>=99 %
%
anisole
99 %
%
2,5-Diformylfuran (DFF
98 %
%
Dioxygen
99.5 %
%
Vanadium oxide
(99.8 %
%
Si/Al
15
NH4-beta
Si/Al
25
NH4-mordenite
Si/Al
10
ammonium metavanadate and oxalic acid
molar ratio
1:2
V2O5
prepared
1-10 wt %
wt %
zeolite-supported vanadia catalyst
prepare
3 wt %
wt %
zeolite
1 g
g
NH4VO3/oxalic acid
added
1.75 mL
mL
NH4VO3/oxalic acid
added
0.378 M
M
ammonium metavanadate and oxalic acid
prepared
70 degC
degC
solids
dried
120 degC
degC
solids
dried
8 h
h
solids
calcined
500 degC
degC
solids
calcined
5 h
h
NH4-beta
suspended
10 g
g
NaNO3
300 mL
mL
NaNO3
1 M
M
mixture
heated
80 degC
degC
mixture
stirred
1 hour
hour
recovered Na-beta material
calcined
500 degC
degC
recovered Na-beta
calcined
5 h
h