Preparation of Ti/PTFE-F-PbO2 Electrode with a Long Life from the Sulfamic Acid Bath and Its Application in Organic Degradation

A polytetrafluoroethylene （PTFE）-doped PbO2 electrode on a Ti substrate was prepared by galvanostatic method from the sulfamic acid bath （Ti/PTFE-F-PbO2-I） or nitric acid bath （Ti/PTFE-F-PbO2-II）. Scanning Electron Microscopy revealed that the Ti/PTFE-PbO2-I electrode had a more regular morphology with smaller size crystals than the Ti/PTFE-F-PbO2-II electrode. On the basis of the results of both the accelerated electrolysis test and the empirical formula for estimating the service life of an electrode, the service life of the Ti/PTFE-PbO2-I electrode was predicted to be more than 7 years under conventional electrolysis conditions （0.1 A·cm^-2）. During the treatment of 4-chlorophenol-contaminated water, the Ti/PTFE-PbO2-I anode showed both a good electro-catalytic activity and high electrochemical stability, exhibiting an excellent potential application.

Carbamate synthesis from amines and dialkyl carbonate over inexpensive and clean acidic catalyst—Sulfamic acid

Sulfamic acid has been proved to be the most efficient and recyclable catalyst in carbamate synthesis from alkylamine and dialkyl carbonate.High selectivity,cost-efficiency and simple product separation were the advantageous features obtained in this process.Sulfamic acid could be reused several times and keep its initial activity in the recycle runs.In addition,sulfamic acid has also exhibited the potential catalytic ability for alkylation of aromatic amines.

Sulfamic Acid as a Cost-effective Catalyst for Acetolysis of Cyclic Ethers

Sulfamic acid has been used as an efficient catalyst and green alternative for conventional acidic materials to promote the acetolysis reaction of THF to produce 1, 4-diacetoxybutane. This method is also applicable in the acetolysis of other cyclic ethers, such as methyl substituted THF and tetrahydropyran and 1,4-dioxane which is less reactivity.

Sulfamic acid as a reusable and green catalyst for efficient and simple synthesis of 2-substituted-2,3-dihydroquinazolin-4(1H)-ones in water or methanol

A series of 2,3-dihydroquinazolin-4（1H）-ones have been synthesized in good to excellent yields through direct cyclocondensation of anthranilamide and aryl aldehydes or ketones in water or methanol under mild conditions.The reaction was efficiently promoted by 10 mol%sulfamic acid（SA,H_2NSO_3H） and the catalyst could be recovered easily after the reactions and reused without evident loss of reactivity.

Synthesis of α-aminonitriles using silica-bonded N-propylpiperazine sulfamic acid as a recyclable catalyst

α-Aminonitriles were synthesized via a one-pot three-component condensation of aldehydes, amines, and trimethylsilyl cyanide using silica-bonded N-propylpiperazine sulfamic acid （SBPPSA） as a recyclable solid acid at room temperature. SBPPSA showed much the same efficiency when used in consecutive reaction runs.

Sulfamic acid:An efficient,cost-effective and green catalyst for crossed-aldol condensation of ketones with aromatic aldehydes under solvent-free

Aromatic aldehydes undergo crossed-aldol condensation with ketones in the presence of catalytic amount of sulfamic acid （SA） to afford the corresponding α,β-unsaturated aldol products under solvent-free conditions in good to high yields at 45-80 ℃.

An Efficient and Solvent-Free Reaction for Synthesis of Bis（indol-3-yl）methanes Catalyzed by Sulfamic Acid

SA （sulfamic acid） catalyzes the reaction of indole with aldehyde and ketone to afford bis（indol-3-yl）methanes in good to excellent yields under solvent-free condition at ambient temperature.

Sulfamic acid as a cost-effective and recyclable solid acid catalyst for Friedel-Crafts alkylation of indole withα,β-unsaturated carbonyl compound and benzyl alcohol

Sulfamic acid was proved to be a cost-effective and recyclable catalyst for Friedel-Crafts type reaction of indole withα,β-unsaturated carbonyl compound and benzyl alcohol.Various indoles,α,β-unsaturated carbonyl compounds and a benzyl alcohol were successfully used in this type of reaction,and the corresponding products were obtained in good to excellent yields.

Silica-bonded N-propyl sulfamic acid as an efficient recyclable catalyst for the synthesis of 3,4-dihydropyrimidin-2-(1H)-ones/thiones under heterogeneous conditions

Silica-bonded N-propyl sulfamic acid （SBNPSA） catalyzed one-pot three component Biginelli condensation of different substituted aromatic aldehydes with ethyl acetoacetate and urea/thoiurea to the respective 3,4-dihydropyrimidin-2-（lH）-ones and thiones in environment friendly procedure is described. The facile reaction conditions, simple isolation and purification procedures of this method make it a good option for the svnthesis of dihydropyrimidinones.

An Efficient, Three-component One-pot Preparation of 1,4-Dihydropyridines Containing Novel Substituted Pyrazole under Sulfamic Acid Catalysis

An efficient approach to 1,4-dihydropyridines containing novel substituted pyrazole is achieved via threecomponent reaction of pyrazolyl aldehyde, β-ketoester, and ammonium acetate in one-pot under sulfamic acid catalysis.

An Efficient and Green One-pot Synthesis of 12-Aryl-8,9,10,12-tetra hyd robenzo[a]xanthen-11 -one Deriva- tives Promoted by Sulfamic Acid in [BMIM]BF4 Ionic Liquid

An efficient and green procedure for the synthesis of novel 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthen- 11- one derivatives has been described through one-pot condensation of 2-naphthol, arylaldehyde and 5,5-dimethyl- cyclohexane-l,3-dione in the presence of sulfamic acid （NH2SO3H） in ionic liquid 1-n-butyl-3-methylimidazolium tetrafluoroborate （[BMIM]BF4）. These reactions proceed with good yields under short reaction time. Furthermore, the green catalytic system can be recycled specific times with no decreases in yields and reaction rates.

Sulfamic acid as a green,reusable catalyst for stepwise,tandem&one-pot solvent-free synthesis of pyrazole derivatives

Sulfamic acid（SA） is a bi-functional, cost-effective and reusable green catalyst for the synthesis of 4-（pyrazol-4-yl）methylenepyrazol-5（4H）-one derivatives by one-pot, three-component condensation of pyrazol-4-carbaxaldehydes, b-ketoesters and phenyl hydrazine（Route-I）. In addition to this method,another simple condensation of pyrazol-4-carbaxaldehydes with pyrazolone in the presence of SA under the solvent-free condition in good yield is reported. The merits of these protocols are mild conditions,non-aqueous workup, high yields, easy availability of the catalyst, no chromatographic separation and inexpensive solid acid catalyst. Furthermore, SA could be recycled and reused for five times without losing its catalytic activity.

Negative inductive effect enhances charge transfer driving in sulfonic acid functionalized graphitic carbon nitride with efficient visible-light photocatalytic performance

Efficient photogenerated carrier migration/separation plays a critical role in increasing the photocatalytic performance of g-C_(3)N_(4).Herein,sulfonic acid group-functionalized g-C_(3)N_(4)(SACN)was synthesized and then synchronously strengthened by a facile-solid-state thermal reaction of g-C_(3)N_(4)and sulfamic acid.As a solid strong acid,sulfamic acid can be used to achieve acid etching on the surface of g-C_(3)N_(4)with the assistance of thermal treatment,leading to an enlarged specific surface area and increased surface catalytic reaction sites.More importantly,our experiments and density functional theory calculations indicate that the driving force generated by the negative inductive effect of sulfonic acid groups significantly improves the charge transfer dynamics and effectively inhibits their recombination.Moreover,the negative inductive effect can induce charge redistribution,which reduces the conduction band potential of g-C_(3)N_(4)to enhance the reduction ability of photo-induced electrons.As a result,the SACN-400 sample showed excellent photocatalytic performance in H2 generation with an apparent quantum efficiency of 11.03%at 420±15 nm,as well as an efficient photodegradation rate for organic pollutants.

Extracting copper from copper oxide ore by a zwitterionic reagent and dissolution kinetics

Sulfamic acid （SA）, which possesses a zwitterionic structure, was applied as a leaching reagent for the first time for extracting copper from copper oxide ore. The effects of reaction time, temperature, particle size, reagent concentration, and stirring speed on this leach- ing were studied. The dissolution kinetics of malachite was illustrated with a three-dimensional diffusion model. A novel leaching effect of SA on malachite was eventually demonstrated. The leaching rate increased with decreasing particle size and increasing concentration, reac- tion temperature and stirring speed. The activation energy for SA leaching malachite was 33.23 kJ/mol. Furthermore, the effectiveness of SA as a new reagent for extracting copper from copper oxide ore was confirmed by experiment. This approach may provide a solution suitable for subsequent electrowinning. In addition, results reported herein may provide basic data that enable the leaching of other carbonate miner- als of copper, zinc, cobalt and so on in an SA system.

硅胶键合N-丙基二乙烯氨基磺酸作为可回收固体酸催化剂催化合成α-氨基腈(英文)

Silica-bonded N-propyl diethylenetriamine sulfamic acid (SBPDSA) is employed as a recyclable catalyst to synthesize α-aminonitriles. These syntheses involved one-pot condensation of an aldehyde, an amine, and trimethylsilyl cyanide under mild reaction conditions at room temperature. SBPDSA was recycled seven times in the condensation of benzaldehyde, aniline, and trimethylsilyl cyanide without reduction of its catalytic activity.

((3-(3-硅胶丙基)硫基)丙基)硫酸酯作为可回收催化剂用于合成4,4'-芳亚甲基-双(1H-吡唑-5-醇)(英文)

Sulfuric acid ([3-(3-silicapropyl)sulfanyl]propyl)ester is employed as a recyclable catalyst for the condensation reaction between aromatic aldehydes and 3-methyl-l-phenyl-5-pyrazolone. This condensation reaction was performed in ethanol under refluxing conditions giving 4,4'-alkylmethylene-bis(3-methyl-5-pyrazolones) in 74-90% yields. The heterogeneous catalyst was recycled and used in eleven runs for the reaction between benzaldehyde and 3-methyl-l-phenyl-5-pyrazolone without losing catalytic activity.

The Three-component One-pot Synthesis of 4,6-Diarylpyrimidin-2(1h)-ones and 9-Phenyl-8-oxa-10,12-diaza-tricyclo[7.3.1.0^(2,7)]trideca-2(7),3,5-trien-11-one

1 Results Pyrimidinones (PMs) are a class of important heterocycles which have been well documented throughout the literature due to their biological importance. They exhibit a wide range of pharmaceutical and therapeutic properties[1].A rapid and efficient one-pot method for the synthesis of 4,6-diarylpyrimidin-2(1H)- ones and related heterocycles is described.The condensation of acetophenone derivatives,aldehydes and urea in the presence of sulfamic acid was employed to synthesize a variety of pyrimid...