454
Hydrogenation of LA and its esters by CTH via Meerwein-Ponndorf-Verley
(MPV) reaction in alcohol as alternative to conventional hydrogenation has been
widely covered in literature [99, 100]. Most of the reports for GVL preparation are
dedicated on the use of LA and/or its esters. This methodology needs a source of
pure LA which is generally derived from furfural. Recently, researchers thought to
prepare GVL directly in one pot from furfural instead of LA to avoid isolation and
further hydrogenation of LA. This one-pot approach can be conceived by the collective action of acid (Bronsted) and reduction (Lewis/base) sites. Roman-Leshkov and
his co-workers firstly disclosed catalytic integrated process for the preparation of
GVL from furfural in a single pot using both Lewis and Bronsted catalysts in the
form of physical mixture [101]. Weibin Fan et al. revealed an integrated process for
GVL preparation from furfural using Au/ZrO 2 and ZSM-5 as combined catalysts
with 80% yield [102]. Winoto et al. used Zr-Al-β-zeolite catalyst containing both
Bronsted and Lewis acid sites for the selective conversion of furfural to GVL. About
95% of GVL yield was obtained over this catalyst within 24 h of reaction time
[103]. More recently, Jungho Jae et al. studied Sn-Al-zeolite catalyst using 2- butanol
as H-donor and reported moderate yield of GVL up to 60% at 180 °C during CTH
of furfural [103]. In another study, Juan A. Melero et al. achieved GVL with 34%
yield directly from xylose using Zr-Al-β-zeolite catalyst at 190 °C within 10 h
[104], and the same catalyst yielded 72% GVL using FA as feed within 24 h [105].
Our group reported a series of catalysts containing metal oxide and heteropolytungstate on H-β-zeolite [106]. In this study we screened various metal oxides such
as Al 2 O 3 , SnO 2 , TiO 2 and Nb 2 O 5 . The catalyst activity was evaluated for the conversion of furfural to GVL, and the results are presented in Fig. 18.
In these catalysts, GVL yield was related on the nature of metal oxide exist in
M-TPA/β-zeolite catalyst. The furfural conversion and GVL yield were low
(20–50%) for the catalysts containing Nb, Ti and Sn oxides. However, the catalysts
with Zr and Al oxides exhibited high conversion with exceeding GVL yield up to
90%. The activity order of these catalysts is as follows: Zr-T-zeolite > Al-T-zeolite
> Sn-T-zeolite > Ti-T-zeolite > Nb-T-zeolite catalysts, where T is tungstophosphoric
acid. The difference in activities was defended in terms of the catalysts’
Fig. 17 Different pathways for the synthesis of GVL
B. S. Rao et al.
Hydrogenation of LA and its esters by CTH via Meerwein-Ponndorf-Verley
(MPV) reaction in alcohol as alternative to conventional hydrogenation has been
widely covered in literature [99, 100]. Most of the reports for GVL preparation are
dedicated on the use of LA and/or its esters. This methodology needs a source of
pure LA which is generally derived from furfural. Recently, researchers thought to
prepare GVL directly in one pot from furfural instead of LA to avoid isolation and
further hydrogenation of LA. This one-pot approach can be conceived by the collective action of acid (Bronsted) and reduction (Lewis/base) sites. Roman-Leshkov and
his co-workers firstly disclosed catalytic integrated process for the preparation of
GVL from furfural in a single pot using both Lewis and Bronsted catalysts in the
form of physical mixture [101]. Weibin Fan et al. revealed an integrated process for
GVL preparation from furfural using Au/ZrO 2 and ZSM-5 as combined catalysts
with 80% yield [102]. Winoto et al. used Zr-Al-β-zeolite catalyst containing both
Bronsted and Lewis acid sites for the selective conversion of furfural to GVL. About
95% of GVL yield was obtained over this catalyst within 24 h of reaction time
[103]. More recently, Jungho Jae et al. studied Sn-Al-zeolite catalyst using 2- butanol
as H-donor and reported moderate yield of GVL up to 60% at 180 °C during CTH
of furfural [103]. In another study, Juan A. Melero et al. achieved GVL with 34%
yield directly from xylose using Zr-Al-β-zeolite catalyst at 190 °C within 10 h
[104], and the same catalyst yielded 72% GVL using FA as feed within 24 h [105].
Our group reported a series of catalysts containing metal oxide and heteropolytungstate on H-β-zeolite [106]. In this study we screened various metal oxides such
as Al 2 O 3 , SnO 2 , TiO 2 and Nb 2 O 5 . The catalyst activity was evaluated for the conversion of furfural to GVL, and the results are presented in Fig. 18.
In these catalysts, GVL yield was related on the nature of metal oxide exist in
M-TPA/β-zeolite catalyst. The furfural conversion and GVL yield were low
(20–50%) for the catalysts containing Nb, Ti and Sn oxides. However, the catalysts
with Zr and Al oxides exhibited high conversion with exceeding GVL yield up to
90%. The activity order of these catalysts is as follows: Zr-T-zeolite > Al-T-zeolite
> Sn-T-zeolite > Ti-T-zeolite > Nb-T-zeolite catalysts, where T is tungstophosphoric
acid. The difference in activities was defended in terms of the catalysts’
Fig. 17 Different pathways for the synthesis of GVL
B. S. Rao et al.