Study on synergistic leaching of potassium and phosphorus from potassium feldspar and solid waste phosphogypsum via coupling reactions

To achieve the resource utilization of solid waste phosphogypsum(PG)and tackle the problem of utilizing potassium feldspar(PF),a coupled synergistic process between PG and PF is proposed in this paper.The study investigates the features of P and F in PG,and explores the decomposition of PF using hydrofluoric acid(HF)in the sulfuric acid system for K leaching and leaching of P and F in PG.The impact factors such as sulfuric acid concentration,reaction temperature,reaction time,material ratio(PG/PF),liquid–solid ratio,PF particle size,and PF calcination temperature on the leaching of P and K is systematically investigated in this paper.The results show that under optimal conditions,the leaching rate of K and P reach more than 93%and 96%,respectively.Kinetics study using shrinking core model(SCM)indicates two significant stages with internal diffusion predominantly controlling the leaching of K.The apparent activation energies of these two stages are 11.92 kJ·mol^(-1)and 11.55 kJ·mol^(-1),respectively.

The Application of Suzuki Coupling Reaction on the Preparation of Carbosilane Dendrimers with 4-(Naphthalen-1-yl)phenyl Core

Carbosilane dendrimers with p-bromophenyl core were synthesized by alternating Grignard and hydrosilylation reaction. And the α-naphthalenyl was connected to the core by the Suzuki coupling reaction. A new carbosilane dendrimer with big π-conjugated structure [4-（naphthalen-l-yl）phenyl core] was given. It shows Suzuki coupling reaction is an effective and powerful core-functionalization method and the satisfactory result can be obtained through prolonging the reaction time with the increase of the generation of dendrimer.

An Efficient System TiCl_4-Al for the Homocoupling Reaction of Aromatic Aldehydes

The reduction of TiCl4(THF)2 with Al in CH2Cl2 gave a green solution of [Ti2(μ-Cl)2Cl4· (THF)4] (1) which was found to promote the reductive homocoupling of aromatic aldehydes to yield symmetrical 1, 2-diols with high diasterepselectivities.

Well-dispersed Palladium Nanoparticles Catalysts Prepared by Wood Nanomaterials for Suzuki Coupling Reaction

Herein, well-dispersed Palladium(Pd) nanoparticles(NPs) with good catalytic activities were prepared using a wood nanomaterial(WNM) as a reductant and a supporting agent. Various factors that influenced the NP morphologies, including reaction time, temperature, and precursor concentration were studied. The as-prepared Pd NPs/WNM showed good catalytic performance for Suzuki coupling reactions.

An Efficient Palladium-catalyzed Coupling Reaction for the Preparation of Biaryls and Polyaryls

In the case of Pd(PPh3)4 as catalyst and toluene as reaction solvent, the desired biaryls and polyaryls were synthesized in excellent yield and on a large scale.

A facile approach to asymmetrical biaryls via coupling reaction of aryl halides with sodium tetraphenylborate catalyzed by MCM-41-supported sulfur palladium(0) complex

Various functionalized asymmetrical biaryls can be synthesized in high to excellent yields via coupling reaction of aryl iodides or bromides with NaBPh4 catalyzed by MCM-41-supported sulfur palladium（0） complex. This palladium complex can be easily recovered and reused many times without loss of activity.

Oxygen-vacancy-anchoring Ni_(x)O_(y) loading towards efficient hydrogen evolution via photo-thermal coupling reaction

Oxygen vacancy(Vo)is a significant component in defect engineering.The present work reports the anchoring effects of initial Vo for further loading modifications and the reducing capacity of photoinduced Vo for pure water splitting.Herein,we propose Ni-loaded Cu-doped TiO_(2)(NCT)materials by successive doping and loading.The continuously added Ni ions should accumulate around the Vos and gradually grow into complete nickel oxide crystals,achieving a higher average valence state of the Ni species.NiO crystals can be detected on a 0.5%NCT sample,while the structure of Ni_(2)O_(3) has been confirmed with a higher nickel mass ratio.Moreover,the introduction of nickel oxide effectively improves the photochemical and electrochemical performance by the interface charge separation,finally reaching an H2 yield of 30.6 pmol/g-cat on 0.5%NCT for Vo-based photo-thermal coupling reaction,which consists of Vo generation in photo and Vo consumption in thermal environment.In situ infrared spectroscopy further indicated that the presence of high valence state nickel oxide hindered the H2 formation but effectively promoted the conventional oxidizing reaction,with an H2 yield of 20.6 mmol/g-cat in a methanol-water reaction on the 2.0%NCT material.In summary,Vo controls the morphological structure of Ni loading and produces diverse effects for reactions with dissimilar mechanisms,which provides a novel way to design modifications for promoting various chemical reactions.

Studies on the Preparation of Bioactive Oligomerstilbene by Oxidative Coupling Reaction(Ⅰ)-Preparation of Shegansu B using Silver Oxide as Oxidant

篢he oxidative coupling reaction of isorhapontigenin using sliver oxide as oxidant afforded a major product, named shegansu B（2）， which was isolated from the roots of Belamcanda chinensis (L．)DC. Both the natural and synthetic Shegansu B have the same potent antagonism activities of leukotriene B4，D4 receptor．

Low-valent Titanium Induced Reductive Coupling Reaction of Aryl Sulfonyl Chlorides with α,β-Unsaturated Esters

The reductive coupling reactions of aryl sulfonyl chloride induced by (TiCl4-Zn) reagent affords diaryl disulfide. However, reaction of aryl sulfonyl chloride with α,β-unsaturated ester under the same condition affords β-arylsulfo ester.

Coupling reaction mechanism of 2-(2-bromo-4-fluorophenyl)-1-cyclohexen-1-yl trifluoromethane-sulfonate

The detailed mechanism of CuI-catalyzed C-O intramolecular coupling reaction of 2-(2-bromo-4-fluoro-phenyl)-1-cyclohexen-1-yl trifluoromethane–sulfonate was studied with the density functional theory(DFT). The geometries of the reactants,transition states, intermediates and products were optimized at the B3LYP/6-31+G* level. Meanwhile, the single point energy of species involved in gas and solvent at B3LYP/6-311+G* level was individually investigated. Polarizable continuum models(PCM)were applied to the dioxane and water solutions at the same level, respectively. Results show that the rate-limiting step, M3→TS3,does not change in different solutions. However, the activation energy in a dioxane solution is lower than that in water, which explains the previous experimental results. Compared with the non-catalyzed reaction process, the activation energy of the ratelimiting step is reduced by 56.53 kJ mol-1 in gas and 44.84 kJ mol 1in solvent, demonstrating a high catalytic efficiency of CuI.

The Intramolecular Coupling Reaction of 1,6-Bis(1-Alky1-2-Methylindol-3-yl)hexane-1,6-dione Induced by Low-valent Titanium

The intramolecular reductive coupling reaction of 1,6-bis(subshtuted indolyl)hexane-1,6-dione using zero-valent titanium reagent as catalyst proderes the novel photochromic 1,2-diheterocyclic cyclohexenes 2, together with unexpected compounds 3

Polyaniline-supported nano metal-catalyzed coupling reactions:Opportunities and challenges

Polyanilines(PANIs) can be easily prepared from the available and cheap anilines via the oxidative polymerization reactions. Owing to the coordination of nitrogen in the material with metals, PANIs are widely used as the support of nano metal catalysts. In comparison with inorganic supports, the nano metals on PANIs were firmly anchored via the coordination bond so that they are not easily to lose during the reaction process. Moreover, since PANIs are versatile materials and their chemical features can be adjusted by introducing functional groups onto the monomers, the catalytic activities of the prepared catalysts are tunable. During the past decade, PANIs-supported nano metal catalysts have been widely applied in a variety of coupling reactions. This review aims to summarize the recent advances and give a perspective.

Recent advances in paired electrolysis coupling CO_(2) reduction with alternative oxidation reactions

Electrocatalytic CO_(2) reduction reaction(CO_(2)RR)holds great promise in green energy conversion and storage.However,for current CO_(2) electrolyzers that rely on the oxygen evolution reaction,a large portion of the input energy is"wasted"at the anode due to the high overpotential requirement and the recovery of low-value oxygen.To make efficient use of the electricity during electrolysis,coupling CO_(2)RR with anodic alternatives that have low energy demands and/or profitable returns with high-value products is then promising.Herein,we review the latest advances in paired systems for simultaneous CO_(2) reduction and anode valorization.We start with the cases integrating CO_(2)RR with concurrent alternative oxidation,such as inorganic oxidation using chloride,sulfide,ammonia and urea,and organic oxidation using alcohols,aldehydes and primary amines.The paired systems that couple CO_(2)RR with on-site oxidative upgrading of CO_(2)-reduced chemicals are also introduced.The coupling mechanism,electrochemical performance and economic viability of these co-electrolysis systems are discussed.Thereby,we then point out the mismatch issues between the cathodic and anodic reactions regrading catalyst ability,electrolyte solution and reactant supply that will challenge the applications of these paired electrolysis systems.Opportunities to address these issues are further proposed,providing some guidance for future research.

Transition-metal-free coupling reactions involving gem–diborylalkanes

Due to the increasing demand for the sustainability of modern organic chemistry, the development of green and powerful methods for C-C and C-B bond formation is highly desired. Among them, the transition-metal-free coupling reactions of gem–diborylalkanes emerge as one valuable tool for organic chemists in the last decade. The review covers selected representative examples. A comparison of these reactions with transition-metal-catalyzed reactions is provided. The recent example of α-boryl radical formation from gem–diborylalkanes is also briefly discussed.

An anthraquinone-based Cu(I) cyclic trinuclear complex for photo-catalyzing C–C coupling reactions

Development of transition metal-based photocatalysts with low cost, strong visible light absorption, and high efficiency is a longstand pursuit for advanced organic synthesis, yet remains highly challenging. In this article, an anthraquinone-based copper(I)cyclic trinuclear complex(1) was designed and it featured strong visible light absorption, high charge separation efficiency and photochemical properties. Complex 1 as a heterogeneous photocatalyst can efficiently catalyze homo-coupling of terminal alkynes and denitrification-oxidative coupling reaction between hydrazinopyridine and terminal alkynes with excellent yield(up to 99%), broad substrate tolerance(27 examples) and superior reusability(up to 10 cycles without loss of performance) under mild conditions.

Microporous Nitrogen-Rich Polymers via Ullmann Coupling Reaction for Selective Adsorption of C_(2)H_(2) over CH_(4)

Acetylene purification from methane is challenging in the field of porous organic polymers(POPs).Herein,we have provided one-pot Ullmann coupling reaction to synthesize a series of POPs with rich N-sites,named FJU-POP-n,wherein the low-cost and non-toxic Cu(acac)2 and environmental-friendly glycerol are employed as catalyst and solvent,respectively.