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A novel [4 + 3] annulation of indoline-based aza-dienes and crotonate-derived sulfur ylides is described. This method could be further expanded by using more efficient synthetic strategies, including three-component [3 + 1 + 3] cascade and the direct sulfide-catalyzed [4 + 3] cyclization. These protocols enable the rapid construction of azepino[2,3- b]indole cores, and a broad spectrum of the desired products with diverse substituents was facilely accessed in generally high yield.

A catalytic highly regioselective, diastereoselective, and enantioselective cyclopropanation of electron-deficient dienes and bromides via direct sulfide organocatalysis is reported. A variety of vinylcyclopropanes featuring a quaternary chiral center were synthesized in up to 99% yield and up to 98:2 enantiomeric ratio (er). These products could be facilely transformed to various interesting molecules with great structural diversity.

It was demonstrated that 3-olefinic oxindoles could generate zwitterionic enolate species with tertiary phosphines and undergo C–C bond formation with various electrophiles in an interrupted Morita–Baylis–Hillman-type reaction manner, followed by a dephosphoration process. Although the in situ formation of phosphorus-ylide intermediates was observed, no Wittig reaction was detected, even in the presence of excess formaldehyde. Moreover, excellent enantioselectivity for the construction of quaternary stereogenic centers was induced with chiral phosphines. Deuterium experiments and density functional theory calculations were conducted to elucidate the reaction mechanism.

A process was proposed for removing and stabilizing arsenic (As) from anode slime. The anode slime with high arsenic concentration was pretreated by circular alkaline leaching process. Then, the arsenic in the leaching solution can be further precipitated as a form of scorodite crystalline (FeAsO 4 ·2H 2 O). In the precipitating arsenic reaction, in which ferrous ions were oxidized by air gas, the effects of acidity (pH), reaction temperature, air flow rate, initial concentration of arsenic and initial molar ratio of Fe(II) to As(V) on arsenic precipitation were investigated. The results showed that sufficiently stable crystal scorodite could be achieved under the condition of initial arsenic concentration of 10 g/L, pH 3.0–4.0, Fe/As molar ratio of 1.5, the temperature of 80–95 °C, and the air flow rate higher than 120 L/h. Under the optimal condition, more than 78% of arsenic could be precipitated as a form of scorodite crystalline. The As leaching concentration of the precipitates was less than 2.0 mg/L and the precipitates may be considered to be safe for disposal.

This research probes into the application of knowledge based engineering (KBE), including acquision, expression and deduction of design knowledge, in rapid design system. Following the concept of modular design and in accordance with the characteristics of machine tool design, it develops a rapid design system for modular machine tool. The design flow of this system is dominantly top-down. It can inherit and reuse design knowledge and realize rapid design of modular machine tool. System development platform and development tools are introduced in this paper. The system’s efficiency and quality are illustrated by a case design.

Highly diastereo and enantioselective [4+2] cycloadditions have been achieved between pyrrolidone-derived cyclic enones and α-haloaldehydes under mild conditions. Relying on extremely reactive in-situ generated chiral N-heterocyclic carbenes, this stereoselective annulation proceeds efficiently even on the gram scale with the catalyst loading as low as 0.025 mol% (250 ppm). A variety of cis-substituted bicyclic dihydropyranones can be produced in up to 96% yield with up to >99% ee. In addition, simple, inexpensive linear aldehydes such as n-propanal can be used directly in asymmetric cycloadditions via oxidative N-heterocyclic carbene organocatalysis with low catalyst loading. This method may provide an economical and practical approach for the asymmetric synthesis of medicinally relevant molecules.

A highly diastereoselective cyclopropanation of cyclic enones with sulfur ylides was developed under catalyst-free conditions, producing multifunctional spirocyclopropanes in generally excellent yields (up to 99% yield and >99:1 d.r.). The asymmetric version of this method was realized by using an easily available chiral sulfur ylide, affording products with moderate to good stereoselectivity.

A stereoselective inverse-electron-demand aza-Diels-Alder cycloaddition process of cyclic 1-aza-1,3-butadienes and α,β-unsaturated aldehydes has been developed via dienamine catalysis. This reaction exhibits excellent β,γ-regioselectivity for enal substrates with substantial structural diversity and broad functionalities, readily producing highly enantioenriched fused piperidine derivatives and enabling efficient sequential construction of complex polycyclic frameworks.

A highly regio- and stereoselective [4 + 2] formal cycloaddition process of cyclohexenylidenemalononitriles and α,β-unsaturated aldehydes has been developed by the catalysis of a chiral secondary amine, affording a range of bridged bicyclo[2.2.2]octane architectures with high molecular complexity (up to 98% ee, >19:1 d.r.).

An asymmetric aza-Diels–Alder and cation–olefin cyclization sequence has been developed to construct cyclopenta[b]piperidine skeletons with moderate yields and excellent stereoselectivities, by employing 5-enals and N-Ts-1-aza-1,3-butadienes as the starting materials. A designed domino cation–olefin/Friedel–Crafts reaction verified that the cyclization of N-Ts iminium ion underwent a stepwise cationic process.

Lead-loaded modified spent grain regenerated by desorption process was investigated. HCl, H2SO4, H3PO4, NaOH, NaCl and ultrapure water were chosen as desorption agents to treat lead-loaded modified spent grain for 30 min. The structures and components of regenerated modified spent grain before and after adsorbing Pb(Ⅱ) were investigated using scanning electron microscopy (SEM), energy-dispersive analysis of X-ray(EDAX) and Fourier transform infrared spectrometry (FTIR). The results indicate that lead-loaded modified spent grain treated in 0.1 mol/L HCl exhibits higher elution efficiency (86.44%) as compared with other agents. The enrichment of carboxyl and hydroxyl groups susceptible to combine with Pb(Ⅱ) are observed in the regenerated modified spent grain, which may result in high re-absorption efficiency of Pb(Ⅱ). Moreover, C-Cl, N-H, C-N and O-H (polysaccharides) also play an crucial role in Pb(Ⅱ) binding to regenerated modified spent grain.

A novel sorbent, bio-formulation(BF), was prepared and employed for the adsorption of cadmium(Cd) ion from aqueous system. The process of adsorption follows the pseudo second-order kinetic equation and the adsorption behavior is fitted with a Freundlich isotherm. The removal rate of Cd is slightly dependent on the initial pH value over a wide range of 4–11. The addition of Zn 2+ and Cu 2+ ions hardly affects the Cd adsorption, whereas the coexisting Pb 2+ ion greatly interferes with the adsorption. The adsorption mechanism is supposed as a cation-exchange process between Cd 2+ and calcium and Mg 2+ present on the surface of BF, and somewhat as adsorption in a hydrolyzed form. The adsorbed Cd ions are desorbed effectively by a 0.1 mol/L HCl solution.

A range of bridged bicyclo[2.2.2]octane derivatives are highly regio- and stereoselectively obtained by reaction of cyclohexenylidenemalononitriles with α,β-unsaturated aldehydes in the presence of proline-type chiral secondary amine catalysts.

A stereoselective inverse-electron-demand aza-Diels–Alder cycloaddition process of cyclic 1-aza-1,3-butadienes and α,β-unsaturated aldehydes has been developed via dienamine catalysis. This reaction exhibits excellent β,γ-regioselectivity for enal substrates with substantial structural diversity and broad functionalities, readily producing highly enantioenriched fused piperidine derivatives and enabling efficient sequential construction of complex polycyclic frameworks.

An asymmetric aza-Diels–Alder and cation–olefin cyclization sequence has been developed to construct cyclopenta[b]piperidine skeletons with moderate yields and excellent stereoselectivities, by employing 5-enals and N-Ts-1-aza-1,3-butadienes as the starting materials. A designed domino cation–olefin/Friedel–Crafts reaction verified that the cyclization of N-Ts iminium ion underwent a stepwise cationic process.

A novel activation strategy, named trienamine catalysis, is applied to the Diels—Alder reaction of 2,4-dienals as trienamine precursors with two classes of olefins.

The discovery of a novel activation mode provided by organocatalysis is presented. It is demonstrated that the merger of optically active secondary amines and polyenals generates reactive trienamine intermediates, which readily participate in Diels-Alder reactions with different classes of dienophiles, hence, providing a facile entry to highly complex molecular frameworks with excellent stereocontrol. For the Diels-Alder reactions with 3-olefinic oxindoles, spirocyclic oxidoles are formed in high yields, and with enantioselectivities in the range of 94-98% ee. It is demonstrated, that some of these products can be transformed into the hexahydrofuro[2,3-b]indole fragment. The organocatalytic trienamine concept has been extended to also include Diels-Alder reactions of olefins substituted with cyanoacetates providing multifunctional cyclohexenes with three contiguous stereocenters in high yield and good stereocontrol. The novelty of this activation strategy lies within the perfect chirality relay over a distance of up to eight bonds. Moreover, we also present the first trienamine tandem reaction by combining trienamine catalysis with enamine activation. In addition to the experimental results, a detailed mechanistic survey is also provided including NMR spectroscopic studies and calculations of the reactive trienamine intermediates, rationalizing the origin of stereochemistry.