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Objectives To validate a new nomogram based on magnetic resonance imaging (MRI) for pre-operative prediction of Ki-67 expression in patients with intrahepatic mass cholangiocarcinoma (IMCC). Methods A total of 78 patients with clinicopathologically confirmed IMCC who underwent pre-operative gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid enhanced MRI between 2016 and 2022 were enrolled in the training and validation group (53 patients and 25 patients, respectively). Images including qualitative, quantitative MRI features and clinical data were evaluated. Univariate analysis and multivariate logistic regression were used to select the independent predictors and establish different predictive models. The predictive performance was validated by operating characteristic curve (ROC) analysis, calibration curve, and decision curve analysis (DCA). The validation cohort was used to test the predictive performance of the optimal model. The nomogram was constructed with the optimal model. Results In the training cohort, independent predictors obtained from the combined model were DWI (OR 1822.741; 95% CI 6.189, 536,781.805; P = 0.01) and HBP enhancement pattern (OR 14.270; 95% CI 1.044, 195.039; P = 0.046). The combined model showed the good performance (AUC 0.981; 95% CI 0.952, 1.000) for predicting Ki-67 expression. In the validation cohort, The combined model (AUC 0.909; 95% CI 0.787, 1.000)showed the best performance compared to the clinical model (AUC 0.448; 95% CI 0.196, 0.700) and MRI model (AUC 0.770; 95% CI 0.570, 0.970). Conclusion This new nomogram has a good performance in predicting Ki-67 expression in patients with IMCC, which could help the decision-making of the patients’ therapy strategies. Graphical abstract

Fuel blending generally exhibits better low-temperature flow properties (i.e. low viscosity, low freezing point) than pure component fuel. Here, a fuel bending containing bicyclohexane and (cyclopentylmethyl)cyclohexane was synthesized directly by hydroisomerization of cyclohexylphenol to reduce the freezing point. The selectivity of (cyclopentylmethyl)cyclohexane formed by isomerization is enhanced through inhibiting the quick hydrogenation of intermediates using mixing acid catalyst and metal catalyst. Zeolite with strong Bronsted acid site and big surface area, such as HZSM-5 is better for the isomerization. Catalyzed by mixture of Pd/C and HZSM-5, the obtained fuel blending improves the freezing point from 2.6 °C to−22 °C compared with pure bicyclohexane, meanwhile keep the high density of 0.880 g/mL unchanged. The improved low-temperature property is contributed to the formation of (cyclopentylmethyl)cyclohexane. Moreover, the pathways of isomerization and its competition with hydrodeoxygenation are also investigated.

Hydrocarbons with a highly strained four-membered ring are synthesized via self-photosensitized [2 + 2] cycloaddition and hydrodeoxygenation using cyclohexene and isophorone as feedstocks, which show high density and high heat values. Photoreaction can take place selectively with isophorone as a self-sensitizer and a reactant. Isophorone/cyclohexene co-cycloaddition has a much faster reaction rate than self-cycloaddition of isophorone, and both DFT calculations and photochemical kinetics show that the energy barrier for the former is much lower than that for the latter. Under optimal conditions, the selectivity of co-cycloaddition and self-cycloaddition can reach 93.3% and 94.9%, with isophorone conversion of 95.4% and 68.8%, respectively. In addition, a series of olefins can undergo self-photosensitized [2 + 2] cycloaddition with isophorone smoothly in high selectivity. After hydrodeoxygenation, hydrocarbons derived from isophorone/cyclohexene mixture and pure isophorone (with an overall yield of 82.1% and 61.3%) have high densities of 0.903 g mL−1 and 0.892 g mL−1, respectively, along with good cryogenic properties. Especially, the hydrocarbons synthesized through photosensitized cycloaddition show considerably higher density and heat values compared with those derived from a common C–C coupling route, which is attributed to the constructed strained cyclic structures. This work provides a new way for photosynthesis of high-energy-density hydrocarbons.

Synthesizing high performance jet fuel from biomass provides potential way to convert low-cost biomass to valuable fuels and meets the requirements of sustainable development. Here, we report a one-pot synthesis of high density and low freezing point jet-fuel-ranged blending from bio-derived phenol and cyclopentanol, which is with high yield, simple and low-cost for scale-up. With the co-presence of acid catalyst like Hβ and metal catlayst like Pd/C, the alkylation first happens to produce bi-and tri-cyclic compounds under N 2 atomphere, then in H 2 atmosphere the remained reactant is partly hydrogenated and takes part in alkylation again to produce cyclic compounds, finally hydrodeoxygenation happens to convert all the compounds to cyclic hydrocarbons. A jet-fuel-blending containing bi- and tri-cyclic alkanes is obtained at high molar yield of 83.9% from the starting reactant, which shows high density of 0.89 g/mL, freezing point lower than −75 °C. Especially, the major component, i.e. cyclopentylcyclohexane shows much better low-temperature properties compared with reported hydrocarbons with similar molecular structure. This result provides a simple, low-cost way to synthesize high performance jet fuel from biomass.

Alkyl-diamondoid fuels are attractive for aerospace vehicles due to their high energy density and supreme low-temperature performance. Here we reported a facile route to synthesize alkyl-diamondoids via solvent-free rearrangement of tetrahydrotricyclopentadiene simply catalyzed by acid. The reaction conditions including catalysts, temperature, catalyst dosage, and solvent were optimized. Notably, under the optimal conditions (10.7 wt% cat., 180 °C, 20 h) an extremely high content of alkyl-diamondoids (85.6%) was found in liquid phase, with high carbon yield of alkyl-diamondoids (60.0%) was obtained. The reaction kinetics of rearrangement has been investigated, and the reaction rate constants and apparent activation energies were calculated based on the experimental kinetic data. The resultant diamondoid-based product shows excellent low-temperature performance and a higher energy content than reported diamondoids and widely used JP-10 fuel, thus is superior as a high-energy-density fuel.

A process via Diels-Alder reaction of lignocellulose-derived 2-methylfuran and petroleum-derived dicyclopentadiene following by hydrodeoxygenation was proposed to synthesize a new kind high-density liquid fuel. The results show that the catalysts, temperature and reactant ratio can affect the product distribution of Diels-Alder reaction greatly. Among the investigated catalysts, HY zeolite exhibited the best catalytic activity and showed good recycling ability. Over HY zeolite, high conversion of reactants along with acceptable selectivity of the target products was obtained, under the reaction temperature of 150 °C and 2-MF/DCPD ratio of 2:1. After hydrodeoxygenation, the as-obtained fuel has a density of 0.984 g/mL, much higher than that of widely used JP-10 fuel (0.94 g/mL), a low freezing point of −58 °C and a volumetric neat heat of combustion of 41.96 MJ/L. Furthermore, a blended fuel with 25% JP-10 exhibits high density and excellent cryogenic properties, which is very promising to serve as high-density fuel for advanced propulsion application.

The photoinduced conversion of biomass-derived chemicals to high value chemicals and advanced fuels is of great significance but still challenging. Herein, a green and efficient self-sensitized [2 + 2] cycloaddition process is developed to convert biomass-derived β-pinene and isophorone to spirocyclic molecules, which cannot be achieved by thermal catalytic conversion. The photoreaction can take place with isophorone as the self-sensitizer, with high selectivity and a yield of up to 91.1%. A triplet sensitization mechanism is disclosed by a combination of triplet quenching, phosphorescence quenching, Stern–Volmer kinetic analysis, DFT calculations and photochemical kinetic studies. When combined with hydrodeoxygenation, spiro-fuel is obtained with an overall yield of 85.0% showing a high density of 0.911 g mL−1 which is 16.8% higher than that of conventional aviation kerosene (ca. 0.78 g mL−1), along with excellent cryogenic properties. Notably the self-sensitized cycloaddition strategy can be extended to a wide range of biomass derived α,β-unsaturated ketones and alkenes. Thus, this work provides a promising ring-increasing route to upgrade low-density bio-derived feedstocks to high-density hydrocarbons.

Bicyclic and multi-cyclic hydrocarbons usually have high density over 0.87 g/cm3, which is very popular to synthesize from biomass-derived renewable chemicals, but their cryogenic properties need to be further improved for practical applications. In this work, we synthesized ethyl-substituted bicyclic high-performance hydrocarbons with improved cryogenic properties from the biomass-derived 4-ethylphenol and phenylmethaol. For the alkylation reaction between 4-ethylphenol with phenylmethanol, the reaction conditions were optimized, under which the conversion of phenylmethanol can achieve 100% with monoalkylated products (2-benzyl-4-ethylphenol and 3-benzyl-4-ethylphenol) selectivity of 71%. After hydrodeoxygenation catalyzed by a mixture catalyst of Pd/C and HZSM-5, the alkylation products were mainly converted to the ethyl-substituted dicyclohexylmethane. The obtained fuel shows a high density of 0.873 g/cm3 (20 °C), gravimetric net heat of combustion of 42.7 MJ/kg, and the freezing point of −42 °C, which is promising to serve as a blend component for jet fuel application.

Given a volume-fixed oil-tank, the advanced fuels with high energy density will increase the payload and range of the aircraft. Herein, we synthesized the high-energy–density liquid fuel via catalytic dimerization of norbornene by the acidic zeolites. Importantly, we reveal the relationship between the structural properties (i.e., B/L acid site ratio and porous structure) of acidic zeolites and the conversion and selectivity of dimerization, and demonstrate the mechanism and kinetics of isomerization-dimerization two-step process. Among the investigated catalysts, Hβ-25 exhibits the best activity with high norbornene conversion and acceptable dimers selectivity, which is attributed to the synergy effect of appropriate B/L acid site ratio and suitable pore size. After hydrogenation, the obtained fuel has high density (0.978 g/cm3) and high volumetric neat heat of combustion (41.49 MJ/L), which are much higher than those of widely used JP-10 fuel. This work provides a promising route to produce high-energy–density fuel for practical application.

Robinson annulation may be useful for converting biomass-derived compounds into jet-fuel-ranged alkylcyclohexanes, but it has not been fully developed until now. Herein, a strategy for the synthesis of highly branched C15 alkylcyclohexanes with lignocellulose-derived furfural and 2,4-pentanedione was developed with Robinson annulation as the key step. Low-freezing-point (−81 °C) and high-density (0.8139 g/mL) highly branched alkylcyclohexanes were produced by two steps, namely, a one-pot cyclization process including the aldol condensation of furfural with 2,4-pentanedione and the subsequent Robinson annulation of the aldol adducts with 2,4-pentanedione over CoCl2·6H2O catalyst, then following with the Pd/NbOPO4-catalyzed hydrodeoxygenation.

Biofuels synthesized from lignocellulose-derived platform chemicals are very attractive for sustainable development. Here we reported a new and facile route to synthesize multi-substituted cycloalkanes with a high density and low freezing point using isophorone and furanic aldehydes (furfural and 5-hydroxymethylfurfural), by solvent-free aldol condensation, followed by hydrodeoxygenation. Catalysts were screened and NaOH showed good performance. The reaction conditions including catalyst dosage, isophorone/furanic aldehyde ratio, temperature and solvent were optimized, and finally the yields of 70.0% for isophorone/furfural and 72.8% for isophorone/5-hydroxymethylfurfural were obtained. Pt/HZSM-5 was prepared as the bifunctional catalyst for hydrodeoxygenation of the condensed product. The resultant multi-substituted cyclohexanes derived from isophorone/furfural and isophorone/5-hydroxymethylfurfural have a density of 0.813 g mL−1 and 0.846 g mL−1 respectively and both have a freezing point lower than −75 °C, and are very promising as stand-alone fuels or additives of other biofuels.

Multi-cyclic hydrocarbons from biomass are sustainable alternative for jet fuel. Here we report an unexpected hydrogenated intramolecular cyclization of diphenylmethane derivatives synthesized by alkylation of bio-derived compounds. With the presence of commonly used zeolite-Pd/C dual catalyst, conventional hydrodeoxygenation (HDO) occurs to produce dicyclohexylmethane. However, when only hydrogenation catalysts like Pd/C or Ni is used, novel intramolecular cyclization takes place to produce perhydrofluorene with the selectivity as high as 96.0%. The two pathways were illustrated by step-by-step controlled reactions in detail and a mechanism was proposed to explain the reason for perhydrofluorene formation. Moreover, this intramolecular cyclization is versatile for diphenylmethane with OCH3 or OH group at any position. The synthesized perhydrofluorene shows density of 0.96 g/mL, much higher than any biofuels reported and even higher than the widely used high-density fuel JP-10 derived from petroleum. It is believed that this biofuel can be excellent additive to improve the density of other jet fuels.

Converting chemicals that can be derived from lignocellulose to cyclic hydrocarbons is a promising route for the synthesis of high-density biofuels. But the low-temperature properties of most synthesized fuels are not good, with high viscosity and freezing point. Herein, we presented the synthesis of cyclohexane derivatives by the alkylation of aromatic oxygenates (anisole, guaiacol and phenol) with furfural alcohol (furfuryl alcohol and 5-hydroxymethylfurfural), followed with hydrodeoxygenation. It is found that FeCl 3 exhibits relatively high activity and selectivity for the alkylation of anisole (guaiacol), and AlCl 3 is the best catalyst for phenol. The selectivity of mono-alkylation product is 71.0%, 92.4% and 84.3% for the alkylation of anisole, guaiacol and phenol with furfuryl alcohol when the reactant ratio is 10, respectively. A semi-continuous operation was adopted for the alkylation of furfuryl alcohol to improve the conversion of aromatic oxygenates. When furfuryl alcohol is replaced by 5-hydroxymethylfurfural, the selectivity reaches almost 100%, but the reaction is a little slower and longer time is needed to get full conversion. After hydrodeoxygenation by combination of Pd/C and HZSM-5, the alkylation product was converted to branched cyclohexane with density of 0.804 g/cm 3 at 20 °C, kinematic viscosity of 34.4 mm 2 /s at − 60 °C and freezing point lower than − 80 °C, which shows great potential as additive to promote the low-temperature properties of other fuels.

Biofuels are important alternative for fossil-based fuel but they have either relatively low density or high freezing point and viscosity. Here we reported a simple and efficient route to synthesis biofuel with density comparable to widely used JP-10 fuel as well as good low-temperature properties. Substituted diphenyl methane was synthesized by acid catalytic alkylation of lignin-derived phenols (phenol, anisole, guaiacol) with benzyl ether or benzyl alcohols, and MMT-K10 exhibits better activity than HPW, Amberlyst-15, and Al-MCM-41, due to the modest acid strength and open lamellar structure. High selectivity along with good-to-excellent conversion was obtained under optimized conditions regardless of different reactant used. Then the alkylated product was subjected to hydrogenation with the presence of Pd/C and HZSM-5, and interestingly, intramolecular cyclization reaction occurred to produce a large amount of perhydrofluorene as well as dicyclohexylmethane. Subsequently, biofuel with density as high as 0.93 g/mL and freezing point as low as −40.0 °C was obtained, which surpasses the state-of-art of biofuel reported.

With the rapid development of spacecraft such as rocket, it is increasingly important to develop high-energy and sustainable fuels. Biofuels synthesized from biomass derivatives provide great convenience for sustainable development. In this work, we reported a route for synthesis of high-energy cyclopropane bio-kerosene by cyclopropanation of myrcene with zinc carbenoid. The reaction conditions including reaction time, reaction temperature, solvent and molar ratio were optimized. Finally, a tricyclic cyclopropane bio-kerosene was synthesized with 69.8% yield under optimum conditions (i.e. zinc carbenoid synthesis temperature of −15 °C, cyclopropanation temperature of 25 °C and solvent of dichloromethane). Importantly, this bio-kerosene possesses a high specific impulse of 328.25 s, much better than the commercial rocket kerosene RP-1, as well as a high net-heat-value of 43.4 MJ/kg and good low-temperature properties.

Renewable high-density spiro-fuels are synthesized from lignocellulose-derived cyclic ketones for the first time, which show higher density, higher neat heat of combustion and lower freezing point compared with other biofuels synthesized from the same feedstock, and thus represent a new type of renewable high-density fuel attractive for practical applications.