A series of Lewis acidic metal salts were used for glucose dehydration to 5-hydroymethylfurfural (HMF) in water. Effect of valence state, ionic radii of Lewis acidic cation, and the type of anions on the catalytic performance have been studied systematically. The experimental results showed that the valence state played an important role in determining catalytic activity and selectivity. It was found that a higher glucose conversion rate and HMF selectivity could be obtained over high valent Lewis acid salts, where the ionic radii of these Lewis acidic metal salts are usually relatively small. Analysis on the effect of the anions of Lewis acid salts on the catalytic activity and the selectivity suggested that a higher glucose conversion and HMF selectivity could be readily obtained with Cl⁻. Furthermore, the recyclability of high valence state Lewis acid salt was also studied, however, inferior catalytic performance was observed. The deactivation mechanism was speculated to be the fact that high valence state Lewis acid salt was comparatively easier to undergo hydrolysis to yield complicated metal aqua ions with less catalytic activity. The Lewis acidic activity could be recovered by introducing a stoichiometric amount of hydrochloric acid (HCl) to the catalytic before the reaction.

Herein, a nanocarbon-poly(ricinoleic acid) composite as a lubricant additive with excellent oil-solubility and dispersity was synthesized using nanocarbon spheres (CNSs) and ricinoleic acid via a “one-pot” approach. The prepared composite was characterized via Fourier transform infrared spectrometry (FTIR), thermogravimetric analysis (TG), Raman spectroscopy (Raman) and X-ray diffraction (XRD). Scanning electron microscopy (SEM) showed that there was no obvious aggregation after surface modification of CNSs. Results demonstrated that the dispersion stability of the composite anti-wear additive in base lubricating oil was significantly optimized. The prepared nanocarbon-poly(ricinoleic acid) composite showed significantly improved stability and dispersity in base lubricating oil for 3 months without obvious precipitation. Tribological tests indicated that the composite lubricant additive exhibited an improved anti-wear performance and better wear resistance than pure CNS additives. The friction coefficients with the composite anti-wear additive dropped from 0.052 to 0.027, which was reduced by 48.1% compared with that of the TMT base lubricating oil. Furthermore, the composite additive is desirable for efficient anti-wear properties in base lubricating oil. The synergistic effect between modified CNSs and poly(ricinoleic acid) significantly improved the wear resistance of the base oil.

This study reports the first synthesis of a new type of ether-polyalphaolefin (DVE-PAO) base oil via free radical bulk copolymerization using triethylene glycol divinyl ether (DVE-3) and α-olefin in drip-feed mode. The characteristic structure of DVE-PAO was characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Nuclear Magnetic Resonance Spectroscopy (NMR). The relative molecular weight and molecular weight distribution of DVE-PAO were determined using gel permeation chromatography (GPC). Structurally, it is a new type of base oil that integrates both polyalkylene glycol (PAG) and polyalphaolefin (PAO) structural units. The research shows that the viscosity of DVE-PAO base oil, the conversion rate of α-olefin, and the pour point of the copolymer increase with rising copolymerization temperature. Additionally, results from the rotating oxygen bomb test indicate that the oxidation stability of DVE-PAO also improves with increasing viscosity. Based on the principles of free radical copolymerization, this study provides a preliminary elucidation of the copolymerization patterns between the aforementioned double-ended vinyl ethers and α-olefins. Furthermore, the DVE-PAO base oil exhibits excellent miscibility with both mineral oils and polyalphaolefin (PAO) base oils. As a result, this ether-based polyalphaolefin is expected to find broad applications in the field of lubricants.

To achieve stable dispersion of ZnO nanoparticles in the base fluid and enhance thermal conductivity (λ), a PGPR@ZnO nano-hyperdispersant was synthesized using polyglycerol polyricinoleate (PGPR) and ZnO. FT-IR and DSC confirmed the bonding interaction between PGPR and ZnO, and zeta potential analysis verified the steric hindrance effect that effectively inhibits particle agglomeration. The PGPR@ZnO was dispersed into di(2-ethylhexyl) carbonate (DEHC) by ultrasonication and stirring, yielding a stable DEHC-PGPR@ZnO nanofluid. This nanofluid achieved a 16.2% increase in λ while retaining the low viscosity and low pour point of the base fluid. Stability assessments showed consistent particle size main peaks before and after static and dynamic tests, with no obvious agglomeration peaks, average particle size variation below 6%, PDI below 0.3, and negligible zeta potential fluctuation. Following static and dynamic stability tests, the thermal conductivity decreased by 0.85% and 7.98%, respectively. These results indicate excellent dispersion stability and provide a valuable reference for evaluating the operational adaptability of the coolant. The nanofluid meets the basic standards for immersion coolants and exhibits a figure of merit (FOM) superior to most oil-based coolants. Compared with PAO2, it offers advantages in raw material availability and resistance to hydrolysis and acidification, providing research and practical foundation for the development of high-performance immersion coolants.