Lactic acid (LA) is an important intermediate in the fine chemical industry because it is utilized as a building block for the production of biodegradable plastics. In this study, a series of tin phosphate phase transfer catalysts modified with several surfactants have been prepared by a facile one-pot synthesis method and tested for the direct conversion of trioses to LA under hydrothermal conditions. Poly(ethylene glycol) (PEG) was identified as the most promising surfactant, and the product distribution closely depended on the reaction temperature, catalyst loading and substrate concentration. Complete DHA conversion and a good yield of up to 96.1% of LA were obtained at 140°C after 4 h of reaction time. Pyridine FTIR demonstrated the presence of Brønsted and Lewis acid sites, which play crucial roles in the dehydration of DHA to pyruvaldehyde (PA) and the following isomerization of generated PA to LA. Furthermore, the isomerization of PA to LA was found to be the rate-determining step. A possible reaction mechanism was proposed: 1) the coordination between PEG and the metal ions caused a greater separation of the tin ions from the phosphate anions, making them more potent Lewis acid sites, and 2) the PEG behaved as a phase transfer catalyst during the reaction. This study paves the way for the further design of improved solid acid catalysts for aqueous phase production of LA from carbohydrates.Catal. Sci. Technol. This journal is † Electronic supplementary information (ESI) available: Catalytic conversion of GLA to LA by SnP with various surfactants, the results of DHA after a prolonged reaction time of 6 h and the postulated roles of SnP-PEG2000. See

Polymerizates of imidazole and epichlorohydrin ([IMEP]Cl) were used to convert simple sugars to lactic acid in water at low temperatures.

Siliceous tin phosphates were demonstrated to be efficient Brønsted–Lewis acid bifunctional catalysts during the conversion of triose sugars to LA under hydrothermal conditions.

Isosorbide is a bio-based functional diol, which is prepared by sequential dehydration of sorbitol and widely used in plasticizers, monomers, solvents or pharmaceuticals. In this study, a variety of acidified...

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A series of BT–cCNT/PDMS and BT–aCNT/PDMS composites were developed by incorporating barium titanate (BT) nanoparticles together with carboxylic functionalized multiwalled carbon nanotubes (cCNT) and amino functionalization multiwalled carbon nanotubes (aCNT) in polydimethylsiloxane (PDMS). Benefitting from the abundant active groups, CNTs and BTs can be in situ “bridged” by hydrogen bond in all of the BT–cCNT/PDMS and BT–aCNT/PDMS composites. Here, we studied the effect of hydrogen bonds (type and amount) between BTs and CNTs at the interface and dielectric properties of the composites. The results indicated that the BT–cCNT/PDMS composite exhibited higher dielectric constant and comparable dielectric loss than the BT–aCNT/PDMS composite, especially when weightCNT < 1 wt%. Also, the dielectric properties of BT–cCNT/PDMS composite show stronger temperature dependence than BT–aCNT/PDMS composite. Finally, the tailorable performance of the polymer‐based dielectric composites can be obtained by regulating the interface with the help of hydrogen bonds.

Tetrahydropyran (THP) represents an O-containing hetero-cyclic compound that can be used as a promising solvent or monomer for polymer synthesis. In this work, Cu-ZnO/Al 2 O 3 catalysts have been prepared by a facile precipitation-extrusion method and used for the synthesis of THP through gaseous-phase hydrogenolysis of tetrahydrofurfuryl alcohol (THFA). The effect of the molar ratio of Cu/Zn/Al, reaction temperature, and hydrogen pressure was investigated. An 89.4% selectivity of THP was achieved at 270 • C and 1.0 MPa H 2 . Meanwhile, the optimum molar ratio of Cu/Zn/Al was determined to be 4:1:10. The Cu-ZnO/Al 2 O 3 catalyst exhibited high catalytic activity and stability for 205 h on-stream. A possible reaction mechanism involving several consecutive reactions was proposed: THFA was firstly rearranged to 2-hydroxytetrahydropyran (2-HTHP), followed by the dehydration of 2-HTHP to 3,4-2H-dihydropyran (DHP) over acid sites; finally, the DHP was hydrogenated to THP. The synergy of acid sites and metal sites of Cu-ZnO/Al 2 O 3 played an important role during the production of THP.

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