Furfural Research Articles

Electrochemical study of the reactivity of furfural and 5-hydroxymethylfurfural with aliphatic primary (di)amines

Furfural (FF) and 5-hydroxymethylfurfural (HMF) are important and prospective renewable sources for chemical, fuel, material or pharmaceutical industry, the furfurylamines being the desired precursors. In this contribution new effects related to the reactivity of FF and HMF with various aliphatic primary (di)amines were observed using an electrochemical approach in water solutions. Following an initial investigation of electroreduction, the course of condensation reactions in basic buffers under various stoichiometric conditions was electrochemically monitored. Using five aliphatic amines and two (α,β- and α,ω-) diamines, a variety of products (mainly Schiff-bases) was identified. As a pilot study for “one-pot” reductive amination, the mixture of FF and n-PrNH2 was electrochemically reduced in basic buffers. The vicinal diamine (analogue of a pinacol) was the main product, together with the expected furfurylamine.

Characterisation of Low Molecular Weight Compounds of Strawberry Tree (Arbutus unedo L.) Fruit Spirit Aged with Oak Wood

There is a trend towards the commercialisation of strawberry tree fruit spirit (AUS) with wood ageing, motivated by its favourable sensory characteristics. Additionally, further studies are necessary to elucidate the optimal conditions regarding ageing time and toasting level. This study evaluated the changes in colour and low molecular weight compounds (LMWC) of AUS aged for three and six months using oak wood (Quercus robur L.) with light, medium and medium plus toasting levels. For this purpose, phenolic acids (gallic, ellagic, ferulic and syringic acids), phenolic aldehydes (vanillin, syringaldehyde, coniferaldehyde and sinapaldehyde) and furanic aldehydes (furfural, 5-hydroxymethylfurfural and 5-methylfurfural) were quantified using the HPLC method. Chromatic characteristics, colour sensory analysis and total polyphenol index were also analysed. Fourier transform near-infrared spectroscopy (FT-NIR) was used to discriminate between samples. The results emphasized the favourable effect of oak wood contact on enhancing the colour and enriching AUS with low molecular weight compounds (LMWC). AUS aged in medium toasted wood exhibits high levels of total phenolic index, 5-hydroxymethylfurfural, furfural, coniferaldehyde, sinapaldehyde, sum LMWC and chromatic characteristics b* and C. Concentrations of syringaldehyde, ellagic acid, vanillin and syringic acid and a lighter colour (a* chromaticity coordinates) are higher in AUS aged with slightly more toasted wood. Nearly all analysed parameters showed an increase with ageing time. The FT-NIR technique allowed for the differentiation of aged AUS, focusing more on ageing time than on toasting level.

Enhanced upgrading of lignocellulosic substrates by coculture of Saccharomyces cerevisiae and Acinetobacter baylyi ADP1

BackgroundLignocellulosic biomass as feedstock has a huge potential for biochemical production. Still, efficient utilization of hydrolysates derived from lignocellulose is challenged by their complex and heterogeneous composition and the presence of inhibitory compounds, such as furan aldehydes. Using microbial consortia where two specialized microbes complement each other could serve as a potential approach to improve the efficiency of lignocellulosic biomass upgrading.ResultsThis study describes the simultaneous inhibitor detoxification and production of lactic acid and wax esters from a synthetic lignocellulosic hydrolysate by a defined coculture of engineered Saccharomyces cerevisiae and Acinetobacter baylyi ADP1. A. baylyi ADP1 showed efficient bioconversion of furan aldehydes present in the hydrolysate, namely furfural and 5-hydroxymethylfurfural, and did not compete for substrates with S. cerevisiae, highlighting its potential as a coculture partner. Furthermore, the remaining carbon sources and byproducts of S. cerevisiae were directed to wax ester production by A. baylyi ADP1. The lactic acid productivity of S. cerevisiae was improved approximately 1.5-fold (to 0.41 ± 0.08 g/L/h) in the coculture with A. baylyi ADP1, compared to a monoculture of S. cerevisiae.ConclusionThe coculture of yeast and bacterium was shown to improve the consumption of lignocellulosic substrates and the productivity of lactic acid from a synthetic lignocellulosic hydrolysate. The high detoxification capacity and the ability to produce high-value products by A. baylyi ADP1 demonstrates the strain to be a potential candidate for coculture to increase production efficiency and economics of S. cerevisiae fermentations.

Photocatalytic reduction of biomass‐derived aldehydes over Pt‐loaded on NiIn bimetallic oxides under light‐emitting diode lighting at mild conditions

Photocatalytic conversion of renewable biomass‐derived aldehydes into high‐valued chemicals is a promising path to meet the growing demand for clean energy and chemical resources. However, the approach still faces challenges, such as limited reaction types and low utilization rates due to the complex functional groups and involved polytropic reaction. In the present work, we developed a catalyst of Pt nanoparticles (Pt NPs) supported on a NiO–In2O3 bimetallic oxide (denoted as Pt/NiInOx) for photocatalytic hydrogenation of furfural (FAL) to furfural alcohol (FOL). Owing to the excellent band structure and efficient internal charge transfer on the p–n heterojunction in the catalyst, the highest 99.9% yield to FOL was obtained over the Pt/NiInOx under a light‐emitting diode (LED) light at low temperatures as 273 K. The combination of ·H dissociated from H2 and oxygen vacancy work synergically to adsorb, activate, and converse C=O to the C–O group. The photocatalytic system presents a highly efficient approach for the rapid hydrogenation of biomass‐based aldehydes under a low LED light radiation intensity at a low temperature. The work is expected to serve as an important reference in constructing bimetallic oxide‐supported active metals, enabling efficient separation of photogenerated electrons and holes, and offering oxygen vacancies in various photocatalytic reactions.

Cis-trans adsorption configuration influenced high-efficient hydrogenation of furfural over zeolite-encapsulated PtCu bimetallic catalyst

Bimetallic catalysts are promising materials for high-efficient conversion of lignocellulose to value-added chemicals, but synthetic methods with reasonable generality are still lacking. Herein, we report a novel method for synthesizing bimetallic catalyst PtCu@S-1(S-1, silicalite‑1) via zeolite encapsulation with the aid of protecting chelating ligands. PtCu@S-1 displays remarkable activity for the hydrogenation of furfural (FUR) to furfuryl alcohol (FOL), and its apparent turnover frequency (TOF) values reach up to 735 mmolFUR·mmolPt−1·h−1 and 88 mmolFUR·mmolCu−1·h−1, which are ∼ 16 and ∼ 4 times higher than that of Pt@S-1 and Cu@S-1. Interestingly, we for the first time find that OO-trans FUR is a preferable adsorption configuration over OO-cis FUR on PtCu@S-1 due to the Pt sites coordinating with the carbon atom on the furan ring. More importantly, the adsorption ability of OO-trans FUR is stronger than that of OO-cis FUR, which increases the concentration of adsorbed species on PtCu@S-1 and accelerates the hydrogenation of FUR.

Steering Selectivity in Electrocatalytic Furfural Reduction via Electrode-Electrolyte Interface Modification.

Electrocatalytic reduction of biomass-derived furfural (FF) represents a sustainable route to produce furfuryl alcohol (FA) and 2-methylfuran (MF) as a value-added chemical and a biofuel, respectively. However, achieving high selectivity for MF as well as tuning the selectivity between FA and MF within one reaction system remain challenging. Herein, we have reported an electrode-electrolyte interface modification strategy, enabling FA and MF selectivity steering under the same reaction conditions. Specifically, by modifying copper (Cu) electrocatalysts with butyl trimethylammonium bromide (BTAB), we achieved a dramatic shift in selectivity from producing FA (selectivity: 83.8%; Faradaic efficiency, FE: 68.9%) to MF (selectivity: 80.1%; FE: 74.8%). We demonstrated that BTAB adsorption over Cu modulates the electrical double layer (EDL) structure, which repels interfacial water and weakens the hydrogen-bond (H-bond) network for proton transfer, thus impeding FF-to-FA conversion by suppression of the hydrogen atom transfer (HAT) process. On the contrary, FF-to-MF conversion was less affected. This work shows the potential of engineering of the electrode-electrolyte interface for selectivity control in electrocatalysis.

Tandem catalysis of furfural to γ-valerolactone over polyoxometalate-based metal-organic frameworks: Exploring the role of confinement in the catalytic process

Polyoxometalate-based metal-organic frameworks (POMOFs) with bifunctional Lewis-Brønsted acid were designed by confining polyoxometalates (POMs: phosphotungstic acid (PW), phosphomolybdic acid (PMo) or silicotungstic acid (SiW)) within the Zr-MOFs. The confined POMs not only have their own Brønsted acid, but can also regulate the Lewis acid strength of the POMOFs via charge regulation, ultimately allowing the POMOFs to display superior catalytic performance in the tandem catalysis of furfural (FAL) to γ-valerolactone (GVL). Among the three catalysts (POMOF-PW, POMOF-PMo and POMOF-SiW), a complete conversion of FAL was achieved, while POMOF-PW exhibited the highest GVL yield (58.1 %) at 160 °C within 23 h. The leaching experiment and structural characterization of the catalyst before and after recycling confirmed the stability of the catalyst structure. The humin originates from the polymerization of furan ring-containing compounds driven by Brønsted acid. The adsorption configuration of the substrate molecules on the catalyst offers a new explanation for the tandem reaction process, i.e. that perpendicular adsorption performs only the first step of the tandem reaction, while the coexistence of perpendicular and horizontal adsorption permits the entire reaction process. This work gives unique insights into the tandem reaction of FAL and can guide the design of efficient tandem reaction catalysts.

Rapid fractionation of pseudo-lignin with high yield by chemical and mechanochemical methods

The formation of pseudo-lignin (PL) is important to promote the refining of lignocellulosic biomass, but there is a problem of low yield of PL. In this study, we developed two chemical and mechanochemical approaches to efficiently extract PL using dilute acid combined with deep eutectic solvent (DES) and double ball-milling and enzymatic hydrolysis (DBEH), respectively. After dilute acid pretreatment at 220 °C for 4 h, due to the degradation of polysaccharides, a large amount of PL was formed and adhered to cellulose. Subsequently, PL was extracted using DES and DBEH, with extraction rates of 30.77% and 30.16%, respectively. There was a little difference in the structure of PL extracted by DES and DBEH, but gel permeation chromatography showed a significant difference in molecular weight between them, with the former having a weight-average molecular weight (Mw) of 1233 g/mol, and a number-average molecular weight (Mn) of 674 g/mol, and the latter a Mw of 5720 g/mol, and a Mn of 3210 g/mol. However, the polydispersity index obtained by both methods was narrow, ranging from 1.78 to 1.83. Moreover, FTIR and 2D-HSQC have provided the PL formation mechanisms. During pretreatment, holocellulose was hydrolyzed to form monosaccharides, which were further degraded to produce intermediates 5-hydroxymethylfurfural (HMF) and furfural (FF). Subsequently, FF and HMF were converted into other aromatic compounds, which then reacted with FF and HMF to form PL. Our study may pave the way for the efficient production of PL.

Total hydrogenation of furfural on Pd/COFs under mild conditions

Total hydrogenation of furfural (FAL) is an efficient way to produce the industrially important tetrahydrofurfuryl alcohol (THFOL). However, it is a challenge to obtain highly selective catalysts for this transformation especially under mild reaction conditions. Herein, we report that the β-ketoenamine-linked covalent organic framework (TpBD COF) supported ultrafine Pd nanoparticles exhibit significantly enhanced selectivity for THFOL compared to Pd/C (95% vs. 82 %) at almost full FAL conversion. This heightened selectivity is attributed to the increased electronic density on the Pd surface, resulting from the electron-donating effect of pendant groups in the TpBD COF. Moreover, kinetic investigations reveal that the activity of total FAL hydrogenation on Pd surface is linked to the rate-determining step in its first C = O hydrogenation process. Additionally, Pd/TpBD COF could catalyse various other bio-based furanic compounds to the corresponding furan ring saturated products in high yields. This work provides guidance for the rational design catalysts to improve its tandem hydrogenation efficiency.

Catalysts Based on Ni and Mg Oxides for the One‐Pot Production of High Added‐Value Products from Furfural

AbstractA family of NiO‐MgO samples with Ni/Mg molar ratio between 0.10 and 0.30 are synthesized by co‐precipitation and subsequent calcination. The characterization of the samples show the formation of a solid solution with a periclase structure in such a way that the Ni2+species are poorly reducible. After the reduction of the NiO‐MgO samples at 500 °C, the catalysts are tested in the furfural (FUR) hydrogenation to obtain valuable products in a one‐pot reaction. The catalysts are highly selective toward tetrahydrofurfuryl alcohol (THFA) with a yield above 50% in most cases as well as 1,2‐pentanediol (1,2‐PeD) and 1,5‐pentanediol (1,5‐PeD) with maximum yield of 22 and 23% after 22 h of reaction at 170 °C and 4 MPa of H2, respectively. The present work also suggests the presence of two routes in the furfuryl hydrogenation. The first one is associated with the reduction of furfural to furfuryl alcohol (FOL) and the hydrogenation of the ring yielding THFA. In the second route, once FOL is formed, the furanic ring is open to form 1,2‐PeD and 1,5PeD.

Removal of phenolic inhibitor compounds from hydrolysates and post-fermentation broths by using a hydrophobic magnetic deep eutectic solvent

Hydroxymethylfurfural (HMF), furfural (FF), hydroquinone (HQ), and vanillin (VAN) are among the main inhibitors generated during most of biomass pre-treatments prior to fermentation processes. They are recognized as toxic to several fermentative microorganisms and therefore cause a decrease in biohydrogen or biofuel production (after hydrolysis). Moreover, if they are released into aqueous solutions (after fermentation), they can be detrimental to the ecosystem. In this research, a new method for removing these inhibitor compounds from the broth after hydrolysis and fermentation is proposed. A hydrophobic magnetic deep eutectic solvent (HMDES), based on menthol: nonanoic acid in a mole ratio of 2:1 was prepared and magnetized with Fe3O4 nanoparticles and applied for effective sorption and removal of these inhibitors from the broth after fermentation and for biomass hydrolysates. Parameters affecting sorption, such as pH, volume of the inhibitors, initial concentration of inhibitors, volume of HMDES, temperature, stirring speed, and contact time, were studied and optimized. Under optimum conditions, the removal efficiency for HQ, HMF, FF, and VAN was obtained as 92.97, 86.72, 82.86 and 95.12% for the model samples. In addition, the removal efficiency of real samples after hydrolysis and fermentation for HQ, HMF, FF and VAN were higher than 83.3, 71.42, 69.99 and 76.80%, respectively. The studies on HMDES regeneration revealed that the removal efficiency remained constant even after undergoing 13 cycles of regeneration. The mechanism of inhibitor removal suggests that hydrogen bonding or van der Waals interactions may serve as the predominant factor influencing the extraction process.

Regulation of acid/basic properties of Zr-Beta zeolite for efficient conversion of furfural to furfuryl alcohol

Zr-Beta zeolites with different acid/basic properties were prepared by hydrothermal and post-synthesis methods and subsequent alkaline treatment. The acid/basic properties of Zr-Beta zeolites were characterized by FT-IR spectra of hydroxyl region and probe molecule adsorption (CD3CN, pyridine and CHCl3). The effects of the acid/basic properties of Zr-Beta zeolites on the conversion of furfural (FUR) to furfuryl alcohol (FAL) via Meerwein-Ponndorf-Verley reduction were investigated and discussed. The results indicate that both Brønsted acid sites, including strong and weak Brønsted acid sites, and Lewis acid sites are effective for conversion of FUR, but high yield of FAL can only be obtained over Zr-Beta with sole Lewis acid sites of framework Zr due to the further conversion of FAL to furfuryl ether, angelica lactone and levulinate ester over Brønsted acid sites. Therefore, Al-free Zr-Beta(h) synthesized in fluoride media is more active and selective than the post-synthesized counterpart. Alkali (earth) metal cations modified Zr-Beta(h) can further eliminate weak Brønsted acid sites of silanols and at the same time generate basic sites. Thus, the activity and selectivity of Zr-Beta(h) are further enhanced. 99.5 % of FAL yield was obtained over Na-Zr-Beta(h) with 99.8 % of FUR conversion at 120 °C for 4 h.

Cu-Doped CoZn@NC promotes catalytic activity of furfural hydrogenation at low temperature: Regulation of copper

The low-cost Cu-based catalysts have excellent selectivity in biomass hydrogenation, but it is challenging to improve their catalytic activity at low temperature. Herein, the trimetallic CuxCoZn@NC (where x = 0.1, 0.3, 0.5 mmol is the molar mass of Cu) were prepared by in suit pyrolysis using trimesic acid with stronger coordination ability. When it was applied to the furfural (FF) selective hydrogenation process, the catalytic yield of the optimal Cu0.3CoZn@NC reached >99 % under mild condition of 90 °C, which was 29 times superior to that of the CoZn@NC without Cu doping. The results demonstrate that the doping of Cu reduces the activation energy of CuxCoZn@NC and increases the catalytic activity at low temperature relative to CoZn@NC. The characterizations and density functional theory (DFT) calculations show that the incorporation of suitable Cu content enhances the interaction between Cu and Co. The amount of surface-active Co0 and the electron density are significantly enhanced, which effectively stimulates the dissociation of hydrogen. Moreover, the Lewis acid content is significantly increased to facilitate the adsorption and activation of FF. Meanwhile, the impact of Cu content variation on the performance of the multi-metal catalyst is discussed. This work is promising to establish a foundation for the accurate design of polymetallic catalysts through adjusting the Cu content to regulate the reaction activity and selectivity.

Facile production of ethyl furfuryl ether via reductive etherification of furfural over Rh nanoparticles supported red mud as a catalyst

Reducing reliance on fossil fuels and mitigating industrial waste are two strategies for clean environmental management. An active research topic within this framework is to convert abundant bio-derived compounds, like furfural (FF), into a petroleum blend by employing industrial waste, like red mud (RM), as catalyst support. Here, we demonstrate that furfural can be chemoselectively converted in a single step into ethyl furfuryl ethers (EFE), which significantly enhance the blended petroleum's octane number. This is achieved in the presence of a recyclable Rh-impregnated RM catalyst. In this context, a range of valuable metals (M = Rh, Ir, and Ru) are impregnated into the RM (M@RM) and extensively characterized by SEM, EDS, XRD, FT-IR, TEM, and XPS. The 1% Rh@RM composite,calcined at 400 °C (1% Rh@RM-400), produced 75 % EFE selectivity with the >99 % conversion of furfural. The prepared catalyst retains its stability for the multiple cycles of the furfural hydrogenation reactions.

Influence of Oxide Coating Layers on the Stability of Gold Catalysts for Furfural Oxidative Esterification to Methyl Furoate

The use of gold nanoparticles (Au NPs) as catalysts has gained widespread attention in various reactions due to their high activity and selectivity under mild reaction conditions. However, one major challenge in utilizing these catalysts is their tendency to aggregate, leading to catalyst deactivation and hindering their amplification and industrial application. To overcome this issue, herein, we used a method by coating the surface of Au NPs with a thin layer of SiO2, which resulted in the formation of a superior catalyst denoted as Au@SiO2/ZA. Characterization studies revealed that the SiO2 layer is coated on the surface of Au NPs and effectively prevents the aggregation and growth of the gold particles during the reaction process, which makes the catalyst display excellent stability in furfural (FF) oxidative esterification to methyl furoate (MF). Moreover, the stabilization strategy is not limited to SiO2 alone. It can also be extended to other oxides such as ZrO2, CeO2, and TiO2. We believe this work will provide a good reference for the design and development of an efficient and stable gold catalyst for the oxidative esterification reaction.

Dynamics-driven tailoring of Zr-embedded hierarchical ZSM-5 zeolites for enhanced catalytic performance from furfural to alkyl levulinate

The tandem reaction for generation of alkyl levulinate (AL) from bio-derived furfural (FUR) is environmental-friendly, in which the bifunctional catalyst with both metal active sites and acid sites are required. In this contribution, a MFI-type nanosponge zeolite with Zr-Al co-framework (Zr@NPZ) were one-pot hydrothermally synthesized using dual-template method. Series characterizations demonstrate that, highly dispersed Zr species embeds in the hierarchical zeolite framework and exhibits typical Lewis acids. Using isopropanol as solvent, Zr@NPZ catalyst gives isopropyl levulinate (IPL) yield up to 75.5 wt% at 180 °C after 2 h reaction from FUR, through sequenced transfer hydrogenation and hydrolysis, with production rates of 11.5 mmol g−1h−1. Moreover, although the enhanced acidities accelerate the conversion rates of FUR, the generation of β-angelica lactone (AGL) from 2-(isopropoxymethyl)furan (IPMF) and conversion of IPL to γ-valerolactone (GVL) are promoted, sacrificing the yield of IPL in the product. The synergism between high dispersed Zr species and moderate acid distribution lead to relative high yield of target IPL.

Alkali-promoted transition-metal-free oxidative condensation of biomass-derived furfural and alcohols

The oxidative condensation of furfural (FUR) with alcohols is considered to be an effective approach for the preparation of liquid transport fuel precursors. In this work, the transition-metal-free oxidative condensation of FUR with alcohols has been introduced, which is achieved by NaOtBu-promoted hydrogen auto-transfer, aerobic dehydrogenation and aldol condensation under atmospheric atmosphere. C3–C10 primary alcohols can be reacted with FUR smoothly to afford C8–C15 condensation products with good to excellent yields at 60–70 °C. Furthermore, the condensation of FUR and C4–C8 secondary alcohols are realized at 25∼40 °C to afford multiple condensation products owing to the multiple active sites of secondary alcohols.

Promoted catalytic performance from furfural to isopropyl levulinate by Zr loaded on defective nanosponge zeolites

Production of alkyl levulinate (AL) from bio-derived furfural (FUR) is environmental-friendly and sustainable. During such process, bifunctional Zr/zeolite catalyst has been demonstrated highly efficient, in which synergism of metal-zeolite and porous structure of catalysts play important roles. In this work, a defective nanoaponge ZSM-5 zeolite loading Zr catalyst is prepared for conversion of FUR to produce isopropyl levulinate (IPL). The defective nanosponge zeolite is hydrothermally synthesized sequenced by acid treatment (NP-A). Then the Zr species were introduced in the as-synthesized NP-A zeolite by impregnation and calcination (Zr/NP-A). The NP zeolite composed of nano-crystalline aggregates deliver hierarchical pores, which promotes adsorption and activation of isopropanol. And the generation of framework Zr accelerates the adsorption of FUR. The as-synthesized Zr/NP-A catalyst give IPL yield up of 77.8 mol% after 3 h reaction at 200 °C with turnover frequency of 8.3 mmol g−1 h−1, which provides an efficient catalyst for production of AL through bio-route.

Development of bimetallic Ru/Ni/SBA-16 catalysts for catalytic hydrogenation of bio-based furfural to 2-methylfuran and furfuryl alcohol

In this work, an efficient bimetallic catalyst was developed to serve as a key factor for the successful hydrogenation of biomass-derived furfural (FF) to the high-value-added chemicals, namely 2-methylfuran (2- MF) and furfuryl alcohol (FA). The bare SBA-16 (SB-16) and Rux/Niy/SBA-16 (RuxNiySB-16) catalysts with different weight percentages (x = 0.2, 0.4, 0.6, 0.8, 0.9 wt% and y = 0.8, 0.6, 0.4, 0.2, 0.1 wt%) were prepared through an in situ hydrothermal method. Characterization using XRD, FT-IR, FE-SEM, EDS, XPS, Pyridine FT-IR, and HR-TEM analysis confirmed the chemical and physical properties of the catalyst. To investigate the catalytic hydrogenation of FF to 2-MF using 2-propanol (2-PrOH) over RuxNiySB-16 catalysts, various reaction parameters such as reaction temperature, time, catalyst loading, and alcohol ratio have been carried out. Among the catalysts tested, the Ru0.8Ni0.2SB-16 catalyst demonstrated outstanding performance under mild reaction conditions, achieving 100% conversion of furfural and an impressive selectivity of 88% towards 2-MF. The high selectivity of 2-MF can be attributed to the combined influence of metal and acid sites on the catalyst surface. Notably, the most active Ru0.8Ni0.2SB-16 catalyst stability was confirmed through five recycling tests, as there was no significant leaching of Ru and Ni. The Ru0.8Ni0.2SB-16 catalyst showed the highest stability based on the recycling test results. The excellent properties of these RuxNiySB-16 catalysts are suitable for various industrial applications, including furfural hydrogenation and other hydroconversion processes.

Zinc/Bismuth-Mediated Allylation Reaction of Biomass Feedstocks: Synthesis of Furanic Diols

AbstractBiomass-based diols have been synthesized by a Zn/Bi-mediated Barbier-type of reaction from furanic aldehydes and allyl halides to access allylated diols. The allylated diols can be readily converted into alkylated diols by hydrogenation. These furanic diols could be potential replacements for fossil fuel based bisphenol A (BPA) which has an adverse endocrine-disrupting effect on humans. This mild and green protocol provides symmetric and nonsymmetric diols in high yields. A chemoselective reduction of allylic double bonds provides diols with unique substitution.