4-Benzyl-4-ethyl­morpholin-1-ium hexa­fluoro­phosphate

The asymmetric unit of the title compound, C13H20NO+·PF6 −, contains two cations, one complete anion and two half hexa­fluoro­phosphate anions having crystallographically imposed twofold rotation symmetry. In the cations, the morpholine rings are in a chair conformation. In the crystal, ions are linked by weak C—H⋯F hydrogen bonds into a three-dimensional network

Organocatalytic Upgrading of Furfural and 5-Hydroxymethyl Furfural to C10 and C12 Furoins with Quantitative Yield and Atom-Efficiency

There is increasing interest in the upgrading of C5 furfural (FF) and C6 5-hydroxymethyl furfural (HMF) into C10 and C12 furoins as higher energy-density intermediates for renewable chemicals, materials, and biofuels. This work utilizes the organocatalytic approach, using the in situ generated N,S-heterocyclic carbene catalyst derived from thiazolium ionic liquids (ILs), to achieve highly efficient self-coupling reactions of FF and HMF. Specifically, variations of the thiazolium IL structure have led to the most active and efficient catalyst system of the current series, which is derived from a new thiazolium IL carrying the electron-donating acetate group at the 5-ring position. For FF coupling by this IL (0.1 mol %, 60 °C, 1 h), when combined with Et3N, furoin was obtained in >99% yield. A 97% yield of the C12 furoin was also achieved from the HMF coupling by this catalyst system (10 mol % loading, 120 °C, 3 h). On the other hand, the thiazolium IL bearing the electron-withdrawing group at the 5-ring position is the least active and efficient catalyst. The mechanistic aspects of the coupling reaction by the thiazolium catalyst system have also been examined and a mechanism has been proposed

Experimental Study on Medium Viscosity Oil Displacement Using Viscoelastic Polymer

With the growing demand for oil energy and a decrease in the recoverable reserves of conventional oil, the development of viscous oil, bitumen, and shale oil is playing an important role in the oil industry. Bohai Bay in China is an offshore oilfield that was developed through polymer flooding process. This study investigated the pore-scale displacement of medium viscosity oil by hydrophobically associating water-soluble polymers and purely viscous glycerin solutions. The role and contribution of elasticity on medium oil recovery were revealed and determined. Comparing the residual oil distribution after polymer flooding with that after glycerin flooding at a dead end, the results showed that the residual oil interface exhibited an asymmetrical “U” shape owing to the elasticity behavior of the polymer. This phenomenon revealed the key of elasticity enhancing oil recovery. Comparing the results of polymer flooding with that of glycerin flooding at different water flooding sweep efficiency levels, it was shown that the ratio of elastic contribution on the oil displacement efficiency increased as the water flooding sweep efficiency decreased. Additionally, the experiments on polymers, glycerin solutions, and brines displacement medium viscosity oil based on a constant pressure gradient at the core scale were carried out. The results indicated that the elasticity of the polymer can further reduce the saturation of medium viscosity oil with the same number of capillaries. In this study, the elasticity effect on the medium viscosity oil interface and the elasticity contribution on the medium viscosity oil were specified and clarified. The results of this study are promising with regard to the design and optimum polymers applied in an oilfield and to an improvement in the recovery of medium viscosity oil

Amplitude Enhancement of Flow-Induced Vibration for Energy Harnessing

In this paper, flow-induced vibrations of bluff bodies with four different cross-sectional geometries (circle, square, triangle and semi-circle) arranged both in single and tandem (gap ratio equals to 3 and 5) configurations are investigated in a wind tunnel. It is found that triangular and square cylinders have the higher amplitude than that of the semi-circular and the circular cylinders in the single configuration. When two cylinders are arranged in tandem, the circular cylinders have the highest amplitude among all tested cylinders. Furthermore, the semi-circular cylinder shows that its vibrating amplitude increases with the reduced velocity in the tandem system due to the galloping effect

Cleavage of non-polar C(sp 2)‒C(sp 2) bonds in cycloparaphenylenes via electric field-catalyzed electrophilic aromatic substitution

Novel methodologies for cleaving inherently inert C(sp 2)‒ C(sp 2) bonds are desirable. Here, the authors report the use of an oriented electric field to cleave C(sp 2)‒ C(sp 2) in cycloparaphenylenes via electrophilic aromatic substitution

Effects of Water-Fertilizer-Air-Coupling Drip Irrigation on Soil Health Status: Soil Aeration, Enzyme Activities and Microbial Biomass

In order to investigate the effects of water-fertilizer-air-coupling drip irrigation on soil health status, including soil aeration (SA), enzyme activity (EA) and microbial biomass (MB), and its response relationship, this glasshouse experiment was conducted using tomato as the test crop, and we designed two fertilization gradients of 135 and 180 kg N·ha−1, two irrigation levels of 0.6-fold and 1.0-fold of the crop-pan coefficient, and two aeration treatments of 5 and 15 mg·L−1 for the three-factor and two-level completely randomized block experiment. The effects of soil dissolved-oxygen concentration, oxygen diffusion rate, soil respiration rate, soil urease, catalase, phosphatase activities and soil microbial biomass were systematically monitored and analyzed in the middle and at the end of crop growth. A structural equation model was used to comprehensively analyze the response relationship among relevant influencing factors. The results showed that coupled drip irrigation increased the soil’s dissolved oxygen, oxygen diffusion rate and soil respiration rate by 14.05%, 30.14% and 53.74%, respectively. Soil urease, catalase and phosphatase activities increased by 22.83%, 93.01% and 61.35%, respectively. The biomass of bacteria, fungi and actinomycetes increased by 49.06%, 50.18% and 20.39%, respectively. The results of a structural equation model analysis showed that water-fertilizer-air-coupling drip irrigation could effectively improve soil health status, and the descending order of influence was MB > EA > SA. This study provides scientific knowledge to reveal the improvement of soil health status by water-fertilizer-air-coupling drip irrigation

Effects of oxygation techniques on growth and physiology of vegetable under subsurface drip irrigation

Perched water often leads to a decrease in soil aeration in subsurface drip irrigated crop roots, whereas aerated subsurface drip irrigation (ASDI) provides a source of oxygen in a root environment that suffers from temporal hypoxia and unlocks yield potentials of crops. With Chinese cabbage as test crop, five irrigation treatments were used including Mazzei air injector (MAI) cyclic aeration, 15 mg/L of hydrogen peroxides (H2O2), fluidic oscillator (FO), oxygen concentrator (OC) and a control treatment (CK). The experiment was carried out during September 23, 2015 to October 31, 2015 at the Central Queensland University, Australia (23°22'0.345"S latitude, 150°31'0.53" E Longitude), and subsurface drip irrigation was implemented to systematically monitor soil respiration, crop growth and physiological indexes to clarify the effect of different oxygation techniques on growth and development of potted Chinese cabbage. Compared with the control treatment, the soil respirations in treatments MAI, H2O2, OC and FO increase by 65.87%, 42.07%, 66.79% and 111.62% respectively compared with CK. ASDI improves the leaf chlorophyll content in treatments MAI, OC and FO. The photosynthetic rate, stomatal conductance and transpiration rate are enhanced by SADI. The photosynthetic rates in MAI, H2O2, OC and FO increase by 868.62%, 794.14%, 778.67% and 650.19% compared with CK. The stomatal conductance in MAI, H2O2 and OC increases by 157.14%, 128.57% and 85.71%, the transpiration rates in MAI, H2O2 and OC increase by 55.61%, 32.38% and 19.58%, and there is not statistically significant difference between other treatments. The yield is significantly increased, and the water utilization efficiency (WUE) is improved, too. The yield increases by 56.36% and 38.72% respectively in treatments MAI and H2O2, and the WUE in MAI and H2O2 increases by 48.96% and 36.46% compared with CK. The beneficial effects of ASDI are mediated through greater root activity, especially the root-shoot ratio increases by 49.61% in MAI. In conclusion, ASDI improves the hypoxic environment in crop roots, promotes the growth of Chinese cabbage, enhances the soil respiration and increases the yield as well as water utilization efficiency. Among four treatments, MAI is ranked in the first place

Factors of relevance for improving the uniformity of oxygen distribution in drip irrigation water

Aerating water using microbubbles in irrigation for drip and subsurface drip irrigation systems has been reported to produce positive effects on plant growth and yield. However, maintaining the uniformity of bubble distribution in irrigation lines across long-row configuration is a challenge. Air injection of microbubbles in irrigation water using a gas diffuser (Seair Diffusion System, Model SA75) has a significant gain in dissolved oxygen (DO) distribution over 850 m length of drip tape. Furthermore, with oxygen injection with a Venturi, DO in irrigation water reached as high as 44 ppm and was maintained well above 35 ppm up to a distance of 700 m and did not drop below 20 ppm, even at a distance of 850 m. Pressure compensated emitters recorded significantly higher DO concentrations compared to non-pressure compensated emitters along the entire length of the irrigation line. Additionally, use of surfactant in irrigation water, up to 4 ppm, resulted in increased gas void fraction and DO concentration compared to the control for both air and oxygen injection irrigation. Highest oxygen saturation was recorded with 4 ppm surfactant, both for air injections (165%) and oxygen injection (438%) treatment along 200 m of non-pressure compensated drip tape