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doi.org/10.1002/open.202100023
ChemistryOpen
Product Control and Insight into Conversion of C6 Aldose
Toward C2, C4 and C6 Alditols in One-Pot Retro-Aldol
Condensation and Hydrogenation Processes
Yingshuang Hui, Yulu Zhan, Wenrong Hou, Lou Gao, Yahong Zhang,* and Yi Tang[a]
Alcohols have a wide range of applicability, and their functions
vary with the carbon numbers. C6 and C4 alditols are alternative
of sweetener, as well as significant pharmaceutical and chemical
intermediates, which are mainly obtained through the fermen-
tation of microorganism currently. Similarly, as a bulk chemical,
C2 alditol plays a decisive role in chemical synthesis. However,
among them, few works have been focused on the chemical
production of C4 alditol yet due to its difficult accumulation. In
this paper, under a static and semi-flowing procedure, we have
achieved the product control during the conversion of C6
aldose toward C6 alditol, C4 alditol and C2 alditol, respectively.
About C4 alditol yield of 20% and C4 plus C6 alditols yield of
60% are acquired in the one-pot conversion via a cascade
retro-aldol condensation and hydrogenation process. Further-
more, in the semi-flowing condition, the yield of ethylene glycol
is up to 73% thanks to its low instantaneous concentration.
1. Introduction
Currently, sugar alcohols mostly come from the fermenta-
tion broth of microorganisms and the hydrogenation of
aldose.[7] For example, sorbitol and mannitol can be obtained
by hydrogenating glucose and mannose.[8] The hydrogenation
of sugar or biomass are usually catalyzed by some support
catalyst based on noble metal such as Ru, Pd and Pt.[9] Perrard
et al. have achieved complete conversion of glucose hydro-
genation over a Ru catalyst loaded on activated carbon with a
sorbitol selectivity of 99.2%.[10] And xylitol can be hydrogenated
by its corresponding sugar xylose.[11] 1,2-PG and EG can be
prepared from the hydration of ethylene oxide and propylene
oxide derived from petroleum cracking.[4] Erythritol, the most
marketable sweet substitute, almost comes from the fermenta-
tion of glucose.[12] At present, there are two chemical processes
to synthesize it, the one is first mixing acetylene and
formaldehyde to obtain 2-butene-1,4-diol, and then oxygen-
ating it into erythritol.[13] The other leverages an industrial
process of starch or cellulose that contains acid and alkali
treating, then oxidization by periodate and hydrogenation by
nickel catalyst under high temperature and high pressure.[14]
In the last decades, hydrolysis of cellulose has attracted
much attention. Scientists have been able to obtain glucose
from cellulose at a high yield. Fukuoka’s group reported for the
first time the ability of using heterogenous catalysts to
depolymerize cellulose into sugar alcohols most of which was
sorbitol.[15] They supplied a promising method producing
polyols and essential value-added chemicals from cellulose in
the presence of a large amount of hydroxy groups. Zhang et al.
developed a route to acquire 61% yield of EG from cellulose
over NiÀ W/C.[16] Palkovits et al. found that cellulose could be
converted into C4À C6 sugar alcohols with a total yield of 81%,
catalyzed by Ru/C combined with heteropoly acid H4SiW12O40
under the conditions of 433 K and 5 MPa of H2.[17] Though the
sugar alcohol yield of 81% is of high level, the yield of erythritol
is less than 6%, and the rest of high yield is mostly contributed
by sorbitol and mannitol.
Biomass-derived alditols, including sorbitol, mannitol, xylitol,
erythritol and others, could be acquired when aldehyde in
sugars is reduced to hydroxy group.[1] Similar to most of sugars,
they could offer a wide range of sweetness. However, excessive
intake of sugar, as all know, will cause human pancreatic islet
dysfunction, diabetes, obesity and other diseases.[2] Fortunately,
not only can sugar alcohols be substitutes for traditional sugar
to satisfy people‘s desire for sweet without causing obvious
changes in blood sugar and insulin, but also they have less
calorigenic properties.[3] In addition, alditols with low carbon
numbers, e.g. 1,2-propylene glycol (1,2-PG) and ethylene glycol
(EG), as essential platform molecules, are widely used in
cosmetic, food and pharmaceutical industry to produce various
value-added derivatives.[4] Among them, C4 alditol is not only
considered as a zero-calorie sweetener but also as a potential
chemical for production of C4 chemicals, such as butadiene,
1,4-butanediol, tetrahydrofuran and other butanediols which
are consumed in large scale and used in many fields.[5] Dean
et al. reported the successful deoxy dehydration to highly
stereospecific olefin from C4-C6 sugar alcohols catalyzed by
methyltrioxorhenium using another alcohol as solvent.[6]
[a] Y. Hui, Dr. Y. Zhan, W. Hou, L. Gao, Prof. Y. Zhang, Prof. Y. Tang
Department of Chemistry
Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials
Laboratory of Advanced Materials, Collaborative Innovation Centre of
Chemistry for Energy Materials
Fudan University, 200433 postcode is missing Shanghai city is missing (P. R.
China)
E-mail: zhangyh@fudan.edu.cn
Supporting information for this article is available on the WWW under
© 2021 The Authors. Published by Wiley-VCH GmbH. This is an open access
article under the terms of the Creative Commons Attribution License, which
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original work is properly cited.
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