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The oxidative cracking of diformyltricyclodecanes (DFTD) to C6–C8 alkenes and alkenes were systematically studied in this work. A series of experiments was performed over a broad range of conditions (temperature: 40–60 °C; oxygen pressure: 0–1.0 Mpa; reaction time: 5–90 min, solvent selection) for exploring the reaction route and mechanism. Results show that the higher temperature and oxygen pressure, as well as tetrahydrofuran (THF) as solvent are of benefit to the generation of cracking products. In addition, the kinetics of this reaction was explored by the dynamic fitting. The obtained kinetics parameters demonstrate that the transformation of intermediate to cracking products possesses higher activation energy than to dicarboxyltricyclodecaneacids (DCTDA), showing that higher temperature is conducive to the generation of DFTD cracking products. This work firstly demonstrated that DFTD could be formed into C6-C8 alkenes containing the same as gasoline compound by the oxidative cracking, suggesting that the by-product of petroleum and coal could be transferred into fuels; this expanded the application of DCPD and will have significant and positive influence on the petroleum and coal chemical industry.

A practical and efficient protocol for the switchable synthesis of sulfoxides, sulfones, and thiosulfonates via Selectfluor-mediated oxidation of sulfides and thiols, respectively, at ambient temperature has been developed. All these organosulfur compounds can be prepared with nearly quantitative yields by applying eco-friendly H2O as O-source. The formation of sulfoxides and thiosulfonates takes only a few minutes (3–20 min). As suggested by the control experiments, the oxidation procedure might proceed through the fluorination of sulfide, nucleophilic addition with H2O, and elimination of hydrogen fluoride.

We report a PhB(OH)2-promoted electrochemical sulfuration-formyloxylation reaction of styrenes employing commercially available thiophenols/thiols as thiolating agents. Specifically, metal catalysts and external chemical oxidants are not needed in the reaction for the formation of β-formyloxy sulfides, and these sulfides can be further converted to (E)-vinyl sulfones via the Selectfluor-mediated oxidation-olefination. Notably, on the basis of this electrochemical oxidation strategy, β-hydroxy sulfide, β-formyloxy sulfoxide, β-formyloxy sulfone, and (E)-vinyl sulfoxide can also be easily prepared.

The conversion of abundant forest- and agricultural-residue-based lignocellulosic materials into high-quality bio-oil by the mild hydrothermal method has great potential in the field of biomass utilization. Some excellent research on biomass hydrothermal process has been completed, including temperature, time, catalyst addition, etc. Meanwhile, some research related to the biomass raw material tissue structure has been illustrated by adopting mode components (cellulose, hemicellulose, lignin, protein, lipid, etc.) or their mixtures. The interesting fact is that although some real lignocellulose has approximate composition, their hydrothermal products and distributions show individual differences, which means the interaction within biomass raw material components tremendously affected the reaction pathway. Unfortunately, to our knowledge, there is no review article with a specific focus on the effects of raw materials and their tissue structure on the lignocellulose hydrothermal process. In this review, research progress on the effects of model and mixed cellulose/hemicellulose/lignin effects on hydrothermal products is initially summarized. Additionally, the real lignocellulosic raw materials structure effects during the thermal process are summed up. This article will inspire researchers to focus more attention on wood fiber biomass conversion into liquid fuels or high-value-added chemicals, as well as promote the development of world energy change.

A transition-metal-free methodology employing nitroenynes and enaminones has been developed to access 3-alkynylpyrrole derivatives. This mild cyclization reaction might proceed through the nucleophilic addition, intramolecular cyclization, and the subsequent elimination processes. The protocol features a broad substrate scope, good selectivity, and functional group tolerance. Notably, the advantage of this method is also highlighted by the controlled reduction to generate alkenyl- or alkylpyrrole derivatives in good to excellent yields.

Hydrothermal process (HT) is an economical and simple method in upgrading agriculture wastes. The liquid product obtained from HT is interesting because of abundant active chemical group. The present work tried to co-heat the HT liquid product of cotton stalk (CS) with heavy crude oil to reduce its viscosity. The optimization study was performed to obtain the best condition of co-heating and mechanism study was completed by comparing the viscosity reduction efficiency and analyzing group composition of crude oil before and after co-heating with HT liquid products of CS, cellulose, hemicellulose and lignin. The results show that the crude oil viscosity reduced obviously after co-heating with CS-HT liquid product under the optimized condition (220°C, 1 h, 3 g treatment liquid, 30 ml crude oil). The preliminary mechanism study results suggest that the main function component of CS that cause viscosity reduction of heavy oil is lignin. The current work provides a new idea of lignocellulosic biomass upgrading and heavy crude oil viscosity reduction.

This work investigates the performance of isooctyl glucoside (APG08) as an emulsifier for the preparation of a Karamay heavy crude oil-in-water emulsion to facilitate its pipeline transportation. First, various factors affecting the rheology and stability of prepared emulsions were studied. The results revealed that the viscosity and stability of emulsions increased with increasing oil content, surfactant concentration, mixing speed, mixing time, and pH of the aqueous phase. Emulsion viscosity was initially unchanged with the increase in homogenization temperature and then increased while emulsion stability decreased. Meanwhile, the optimal values of key parameters were 75 wt % oil content, 0.5 wt % surfactant concentration, temperature of 30 °C, mixing speed of 750 rpm, mixing time of 10 min, and aqueous phase pH of 11.14, resulting in a viscosity reduction of 88.82% and emulsion stability up to 48 h at 96.27%. In addition, a qualitative relationship between the stability and rheology of emulsions was elaborated by analyzing the experimental results. The findings showed that an increase in emulsion stability was accompanied by an increase in emulsion viscosity. Therefore, emulsion viscosity cannot become very high while improving emulsion stability to ensure proper transportation.

Herein, a selective tandem C-C bond-forming reaction with CO2 was developed to realize the bridging of enaminones and synthesis of 1,4-dihydropyridines, respectively. n-Butylamine significantly promoted this CO2 deoxymethylenation procedure catalyzed by 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) and ZnCl2. The mechanism involving the formation of bis(silyl)acetal, nucleophilic addition, and amine elimination was also interpreted to clarify the bridging of two molecules of enaminones with CO2 and the generation of dihydropyridine derivatives.

A methodology employing CO2, amines, and phenylsilane was discussed to access aryl- or alkyl-substituted urea derivatives. This procedure was characterized by adopting hydrosilane to promote the formation of ureas directly, without the need to prepare silylamines in advance. Control reactions suggested that FeCl3 was a favorable additive for the generation of ureas, and this 1,5,7-triazabicyclo[4.4.0]dec-5-ene-catalyzed reaction might proceed through nucleophilic addition, silicon migration, and the subsequent formal substitution of silylcarbamate.

With the fast development of a micro-extraction system, the need for development and systematic study on microseparators is growing. In this study, a T-shaped microseparator was designed to separat...

We conducted the removal of hydrocarbons and concentrating of H2 from the tail gas of diesel hydrogenation (tail gas for short) using hydrate separation method. Based on the preliminary separation results, it is necessary to apply hydrate thermodynamic promoter to further improve the separation efficiency. In order to avoid the introduction of new impurity, we added propane (C3H8), one component of tail gas, in the feed gas as the hydrate promoter by reverse thinking, because it runs counter to the hydrocarbons removal from tail gas. The formation equilibrium conditions of tail gas hydrates were measured, and the enthalpy of hydrates equilibrium dissociation was calculated by the Clausius–Clapeyron equation. The results show that the addition of C3H8 significantly decreases the formation equilibrium pressure of tail gas hydrates at the same temperature. It indicates that C3H8 indeed performs as a thermodynamic promoter for tail gas hydrates. Consequently, the driving force for hydrates formation increases, and more hydrates form at the equilibrium state. As a result, the total removal rate of hydrocarbons and the recovery rate of H2 are both increased, while the concentration of H2 in equilibrium gas almost keeps unchanged. The results demonstrate that the addition of C3H8 behaves as an inducer to enclose relatively more hydrocarbons into hydrate phase, and it also accelerates the hydrates formation rate at the same time. This work presents a new research idea, i.e., cast a small fish for a big one, for the flexible and optimum application of hydrate separation technology.

Recovery of H2 and N2 from the tail gases of the ammonia synthesis plant could significantly improve the ammonia output and economic benefits. In this work, we measured the formation conditions of ...

A methylenation-cyclization reaction, employing cyclic enaminones with primary aromatic amines and two molecules of CO2, furnishing fused-tetrahydropyrimidines, is discussed. In this Cs2CO3 and ZnI2 catalyzed one-pot two-step procedure, two molecules of CO2 were selectively converted to methylene groups. The multi-component reaction might proceed through the formation of bis(silyl)acetal which was followed by condensation and further aza-Diels-Alder reaction. Hydroquinazoline, hydrocyclopenta[d]pyrimidine and hydroindeno[1,2-d]pyrimidine derivatives could be prepared with CO2 as the C1 source, effectively.

Biogas is one of the green energy resources. To enhance usage of biogas (64.0 mol % CH4/CO2) and reduce the greenhouse effect, CH4 purification by the hydrate-based gas separation (HBGS) technology...

A transition-metal-free methodology employing nitroenynes and enaminones has been developed to access 3-alkynylpyrrole derivatives. This mild cyclization reaction might proceed through the nucleophilic addition, intramolecular cyclization, and the subsequent elimination processes. The protocol features a broad substrate scope, good selectivity, and functional group tolerance. Notably, the advantage of this method is also highlighted by the controlled reduction to generate alkenyl- or alkylpyrrole derivatives in good to excellent yields.

Study on the gas hydrates in porous medium has great significance to the formation, accumulation and exploitation of natural gas hydrate (NGH). Consequently, we investigated the formation/dissociation of ethane hydrate in a sub-millimeter sized capillary in this work, and observed the appearance and kinetic rate during the hydrate formation/dissociation process. The dissociation equilibria of ethane hydrate in capillary was measured first, then the influences of hydrate memory effect (dissociation temperature and time) and degree of subcooling on ethane hydrate formation were obtained, respectively. The results demonstrate that hydrate forms more difficultly in capillary than in conventional macro-reactor because of the fluid resistance effect and poor mass transfer of gas-liquid. The appearance and formation kinetics of ethane hydrate are greatly influenced by the memory effect and subcooling degree. The morphology of ethane hydrate formation on the bubble surface in water bulk phase shows that “bridge effect” occurs during the hydrate formation and growth in capillary.

The separation and utilization of coal bed methane have great research and economic significances. Consequently, we investigated the two-stage separation of CH4/N2 binary gas mixture, an analogue of coal bed methane, using hydrate separating method in this work. In order to realize green environmental protection and promote the popularization of hydrate separation method, two biological additives, i.e., tea polyphenol and catechin, were applied to recovery CH4 by forming bioclathrates. The influences of tea polyphenol and catechin on hydrates thermodynamic phase equilibria, kinetic hydration rate, gas storage capacity and separation effects were systematically studied. The results show that these two bio-additives could significantly increase the formation rate and gas storage capacity of hydrates in comparison with pure water system. In addition, the recovery of CH4 and separation factor are also enhanced in the presence of bio-promoters. Therefore, the formation of bioclathrates is helpful to protect environment, and promote the industrial application of the hydrate separation technology.

CH4 purification and CO2 removal by hydrate-based separation method from the simulated biogas (64 mol % CH4/CO2) were investigated in tetrabutylammonium bromide (TBAB) solution. Three different hyd...

Alkyl polyglucosides have attracted great research interests as environmental-friendly biological surfactants. Consequently, we investigated the effects of n-hexyl polyglucoside and octyl-decyl pol...

[C8min] BF4 was used in this work to combine with TBAB or THF for the investigation about thermodynamic and kinetic additives on CO2 and CH4/CO2 hydrates. The results show that [C8min] BF4 has the inhibition effect on the equilibrium of hydrate formation. About the kinetic study, [C8min] BF4 could improve the rate of CO2 hydrate formation and increase the gas uptake in hydrate phase. At the same time, the combination of TBAB and [C8min] BF4 could increase the mole friction of CH4 in residual gas comparing with the data in THF solution. CH4 separation efficiency was strongly enhanced. Since that the size of CO2 and CH4 molecules are similar, CH4 and CO2 could form the similar hydrate, so the recovery of CH4 from biogas decreases lightly. The CH4 content in biogas can purified from 67 mol% to 77 mol% after one-stage hydrate formation. In addition, the combination of THF and [C8min] BF4 do not have obvious promoting effect on CH4 separation comparing with the gas separation results in pure THF solution.

A algorithm coupled with modified Patel-Teja equation of state and Chen-Guo hydrate model is developed to conduct vapor-liquid-semiclathrate multiphase flash calculation for TBAB containing systems. To quantitatively describe the gas consumption ability of semiclathrate slurry, a new concept, i.e., the apparent liquid phase, is introduced. The Patel-Teja equation of state (PT EOS) combined with a Debye-Huckel electrostatic term is chosen to describe the fugacity of TBAB in aqueous solution and calculated gas solubility in aqueous phase. The Chen-Guo hydrate model is extended to calculate the fugacity of TBAB in semiclathrate phase. Several parameters in Chen-Guo model for TBAB are retuned by correlating phase equilibrium data. A mathematical approach based on the secant iteration is successfully applied to solve flash calculation. Results from flash calculations are in satisfactory agreement with experimental data reported in other literature. This new algorithm provides an extended range of calculations for semiclathrate phases, such as amounts of semiclathrate formed, and then, the contributions of absorption and hydration upon separation performance can be quantitatively described. In addition, multistage separation are simulated using this flash algorithm. The effects of TBAB concentration of solution, initial gas liquid volume ratio, temperature, and pressure on separation efficiency are systematically discussed from the perspective of thermodynamics and mass balance.

The effects of mung starch on methane hydrate formation equilibria/rate and gas storage capacity were investigated in this work. Mung starch at three concentrations of 100, 500, and 800 ppm were tested comparing with the pure water. The results show that mung starch has slight thermodynamic promotion effect on methane hydrate formation, because it decreases the gas-liquid-hydrate three-phase equilibria pressure at the same temperature. The formation rate and gas storage capacity of methane hydrate in the presence of mung starch were studied at 8.0 MPa and 275.15 K–281.15 K. The results demonstrate that mung starch significantly accelerates methane hydrate formation rate. It could shorten the induction time and reaction time of methane hydration process. In addition, the gas storage capacity of methane hydrate is also increased greatly. The solubility data of methane indicate that mung starch indeed plays a role of solubility enhancement. The green and environmental friendly characteristics of mung starch could be helpful to promote the application of hydrate-based technology.

In this work, we evaluated the influence of phosphoric acid in conjunction with a tannic converter formula on the adhesion of the coating system by employing the epoxy coating as the top coating. The morphology and the composition of the rusted steel before and after treatment were determined by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. The adhesion test result showed that the adhesion strength between the rust and the epoxy coating was enhanced from 1.93 MPa to 11.63 MPa with the treatment by 50 g/L phosphoric acid in conjunction with a tannic converter formula. Further investigation of the working mechanism of such treatment revealed that the adhesion improvement could be attributed to the formation of a micro-cracked and compact conversion layer. This layer could reinforce the anchoring of epoxy coating through the pinning effect. It was also found that both the pH and the phosphate radical were the important factors to improve the adhesion strength.

Herein, a selective tandem C-C bond-forming reaction with CO

A methylenation-cyclization reaction, employing cyclic enaminones with primary aromatic amines and two molecules of CO

The thermodynamic equilibrium conditions for binary gas mixtures of CH4 and H2 in the presence of TBAB were measured using the T-cycle method in this study. The experiments were conducted in the temperature range from (282.37 to 296.45) K and the pressure range from (0.46 to 15.47) MPa. The mole fraction of H2 in gas mixtures varied from 0.15 to 0.85. The mass fraction of TBAB solution ranged from 0.10 to 0.50. The experimental results showed that the addition of TBAB can dramatically reduce the pressure required for hydrate formation at a fixed temperature. The equilibrium pressure increased along with the increasing composition of H2 in the gas mixture. In order to gain a better understanding on the impact of TBAB on the thermodynamic equilibrium conditions for binary gas mixtures, a comparison was made between our data and phase equilibrium conditions for THF hydrates formed from the same gas mixture. The results showed that the thermodynamic promoting effect of TBAB was superior to that of THF when th...

CH4 concentration and CO2 separation from biogas (CH4/CO2) by an one-stage hydrate formation was supposed to be a prospective and economical practicable technology compared with traditional gas sep...

During oil recovery process, the equilibrium state of asphaltene–oil solution system and colloidal system in porous media is altered, which could cause asphaltene to precipitate from crude oil in rock pores. This severely results in the alteration of wettability, permeability, and porosity of formation and damages oil reservoir formation. Nanoparticles have recently been considered as effective asphaltene inhibitors. Several experimental works were carried out to study the impact of nanoparticles on asphaltene precipitation. The majority of these studies were performed using core-flooding experiments in bulk phase. However, few experimental investigations were performed to directly reveal the impact of nanoparticles on asphaltene aggregation based on the direct pore-scale visual evidence. In this work, a novel method was employed to make direct visualization and measurement on the kinetics of asphaltene aggregation in the presence of nanoparticles in a microcapillary. NiO, SiO2, and Fe3O4 nanoparticles we...