Oxidation of Partially Hydrolyzed Polyacrylamide from Polymer Flooding Processes Using Fenton Reagents

The degradation of partially hydrolyzed polyacrylamide(HPAM) found in alkaline/surfactant/polymer flooding sewage was investigated using Fenton-type reagents. Different Fenton reagent treatments for HPAM degradation were compared. The effects of pH, hydrogen peroxide(H_(2)O_(2)), ferrous ion(Fe^(2+)), and tartaric ion(C_(4)H_(4)O_(6)^(2-)) concentrations were studied. The degradation reaction occurred within a wide range of pH(3–9). The HPAM degradation performance of photo-Fenton processes using solar light and UV were compared with that of the Fenton process. The degradation rate was found to be strongly dependent on the H_(2)O_(2)/Fe^(2+)/C_(4)H_(4)O_(6)^(2-)molar ratio. The HPAM degradation efficiency was 90%, and the chemical oxygen demand removal efficiency was 85%. HPAM could be degraded into a compound with a lower molecular weight, but it was difficult to achieve complete mineralization to CO_(2). The presence of intermediate products hindered further oxidation in the Fenton process.

Exploitation of Fenton and Fenton-like reagents as alternative conditioners for alum sludge conditioning

The use of Fenton＇s reagent （Fe^2＋/H2O2） and Fenton-like reagents containing transition metals of Cu（Ⅱ）, Zn（Ⅱ）, Co（Ⅱ）, and Mn（Ⅱ） for an alum sludge conditioning to improve its dewaterability was investigated. The results obtained were compared with those obtained from conditioning the same alum sludge using cationic and anionic polymers. Experimental results show that Fenton＇s reagent was the best among the Fenton and Fenton-like reagents for the alum sludge conditioning. A considerable effectiveness of capillary suction time （CST） reduction efficiency of 47% can be achieved under test conditions of Fe^2＋/H2O2 = 20/125 mg/g DS （dry solid） and pH 6.0. The observation of floc-like particles after Fenton＇s reagent conditioning of alum sludge suggested that the mechanism of Fenton＇s reagent conditioning was different from that of polymer conditioning. In spite of the lower efficiency in the CST reduction of Fenton＇s reagent in alum sludge conditioning compared to that of polymer conditioning, Fenton＇s reagent offers a more environmentally safe option. Tiffs study provided an example of proactive treatment engineering, which is aimed at seeking a safe alternative to the use of polymers in sludge conditioning towards achieving a more sustainable sludge management strategy.

Stereoselective Addition of Organotitanium and Grignard Reagents to 3,5-O-isopropylidene-L-glucurono-γ-lactone

Substituted PhMgX and PhTi(OCHMe2)4MgX react with 3,5-O-isopropylidene-L-glucurono-γ-lactone 4 to give tetrads 5a-e and its stereoisomers 6a-e Tetrads 5a-e are the important intermediates in the synthesis of howiinol Al and its derivatives. The stereoselectivities of substituted PhTi(OCHMe2)4Mg (5a-e:6a-e ratio, 68-72:32-28) were better than those of substituted PhMgX(33-64:67-36) in the reaction. The effects of different substitUted groups and positions (p-Me, m-Me, o-MeO, p-Cl) of the phenyl ring on their stereoselectivies were not significant.

Nickel (Ⅱ) Complex Catalyzed Conjugate Addition Reaction of Functionalised Organozinc Reagents to α,β -Unsaturated Esters

Functionalized organozinc reagents can easily under 1, 4-addition reaction withunsaturated esters in the presence of catalytic amount of Ni (acac)_2 and tertiary ammes under verymild conditions to give the products in excellent yields.

Development of Standard Reagents for Avian Influenza Virus Subtypes Diagnosis

Avian influenza(AI)is one of the most relevant viruses in the poultry industry.The AI virus(AIV)transmission from birds to human causing severe cases and mortality enhanced the magnitude of AI for public health.Consequently,the AIV diagnosis laboratories should be able to detect and identify endemic,epidemic and seasonal influenza strains and other wildlife influenza subtypes that cross the country’s borders.The development in quality controls in according with international rules comes to improve the performance of tests.With this purpose,the Brazilian Reference Laboratory for Avian Influenza(LANAGRO-SP)established a cooperation with the World Organization for Animal Health(OIE)to produce AIV master seeds,inactivated antigens and antiserum to attend the necessities of Brazil and other South America countries under the high quality control for all test.Seventeen of AIV master seed lots and seventeen of inactivated antigens lots produced reached hemagglutination(HA)titers of 1:512 and 1:256,respectively.In addition,fifteen AIV antiserum lots with hemagglutination inhibition(HI)titers reaching 1:4,096 were obtained.The AIV reference reagents produced and applied in laboratory routine successfully.

Influence of the Precipitating Reagents and Dispersants on the Formation Nano-Aluminum Hydroxide

The influence of the precipitating reagents and dispersants on the formation of nano-aluminum hydroxide from sodium aluminate solution by chemical precipitation was investigated. The influence of the dispersed seeds on the decomposi-tion process was investigated too. The alkaline aluminate solutions were used as original solutions with a concentration of Al2O3 having 14.78 g/dm3, αk—1.6 and127 g/dm3, αk—1.6. For the precipitation processes there were used follow-ing precipitating reagents—solutions HCl, NaHCO3 and NH4HCO3 with a concentration of 80 g/dm3, dispersants—PEG 6000, (NaPO3)6 and Tween 20. For the decomposition process the dispersed seeds and factories seeds were used. Structural studies of the aluminum hydroxide particles were carried out by means of the electron-probe microanalysis and scanning electron microscopy, and phase composition of products was determined by means of X-ray diffraction analysis. Ammonium bicarbonate and Tween 20 were determined as the optimal precipitating reagent and dispersant, correspondingly, resulting in dispersed aluminum hydroxide, which is used as a seed in the decomposition process. It was established that this product in form of dispersed seed considerably reduces the duration of the decomposition process;the maximal decomposition of solution (73.9%) was observed after injection of dispersеd aluminum hydroxide into solution. The final aluminum hydroxide having 90% of particles less than 100 nanometers was obtained within 7 hours of steady decreasing temperature from 70°C to 48°C.

Effect of ultrasonic irradiation on particle size,reagents consumption,and feed ash content in coal flotation

Ultrasonic waves have a lot of use in the particle surface cleaning.As flotation is one of the methods associated with surface properties,this paper investigates the effect of these waves on performance,particle size,reagents,and feed ash content in coal flotation.To accomplish this goal,coal samples in three size fractions,including coarse(-800 to+400μm),medium(-400 to+100 μm)and fine(-100μm)with various feed ash content.The flotation experiments were evaluated by process indexes such as yield,combustible recovery,and selectivity index.The results indicated the increasing of yield.The increasing was significant in medium size.Furthermore,the results showed that in presence of ultrasonic waves,the collector and frother consumption decreased.And also,applying ultrasonic waves would result more combustible recovery and selectivity index.The ash selectivity index had the highest impact for high feed ash content.

Synthesis of Symmetric Diketones from Imidazolinium Salt and Bis-Grignard Reagents

The reaction of 2-substituted imidazolinium salt with bis-Grignard reagents is reported and a new method for the synthesis of symmetric diketones from carboxylic acids and bis-Grignard reagents is provided.

Prediction of Molar Absorptivities of Color Reagents and Their Color Reactions with Yttrium by Artificial Neural Networks

The new topological indices A x1 A x3 suggested in our laboratories were applied to the study of structure property relationships between color reagents and their color reactions with yttrium. The topological indices of twenty asymmetrical phosphone bisazo derivatives of chromotropic acid were calculated. The work shows that QSPR can be used as a novel aid to predict the molar absorptivities of color reactions and in the long term to be helpful tool in color reagent design. Multiple regression analysis and neural network were employed simultaneously in this study. The results demonstrated the feasibility and the effectiveness of the method.

Can inhibition of telomerase increase pancreatic cancer cell's susceptibility to chemotherapeutic reagents?

Objectives: To clarify the inhibition of pancreatic can-cer cells by interference with the hTR component of thetelomerase reverse transcriptase enzymatic complexand evaluate susceptibility of antisense hTR pancreaticcancer cells to chemotherapeutic reagents.Methods: A 593 bp of full length hTR cDNA was sub-cloned into a mammalian expression vector pcDNA3.1(-) in antisense orientation to construct an antisensehTR expression plasmid. The plasmids were introducedinto Pancl cells, a human pancreatic carcinoma cellline, by lipofectin, and G418-resistant stable trans-formants were expanded. Resulting stable clones werescreened for the presence of hTR insert by PCR withT7 and BGH reverse primers located on the flanks ofthe multiclonal site of pcDNA3.1 vector. Cell growth rate,hTR expression, telomerase activity, and anchorage-in-dependent growth property were analyzed. Finally, sus-ceptibility of antisense hTR cells to chemotherapeuticreagents was evaluated.Results: Significant downregulation of endogenous hTRwas evident in the antisense-hTR transformed cells,and telomerase activity was markedly decreased com-pared to control cells in standard TRAP assays. Fur-thermore, the proliferation and the anchorage-inde-pendent growth ability in antisense-hTR expressingcells were significantly decreased compared with thecontrol parental cells. However, no crisis or senescencephenomena was observed. Antisense hTR appears toincrease Pancl cell's susceptibility to chemotherapeuticreagent cDDP, but not to differentiation reagent DM-SO, COX2 inhibitor sulinbac, NS-398, curcumin, andchemotherapeutic reagent adriamycin(ADM).Conclusions: These data indicate that hTR is probablya critical component of human telomerase activity andthat downregulation of the RNA component of humantelomerase is an effective target for anticancer strategyand antisense hTR can increase Pancl cell's susceptibilityto cDDP.

SYNERGISTIC EXTRACTION OF Cd(Ⅱ)WITH PRIMARY AMINE N-1923 AND NEUTRAL ORGANOPHOSPHORUS REAGENTS

The synergistic extraction of Cd(Ⅱ)with primary amine N-1923 and neutral organophosphorus reagents(TBP,DBBP,B)from hydrochloric acid has been investigated at μ=0.5,t=25℃.The compositions of the synergistic extraction complexes and the mechanism of the synergistic extraction have been determined by the methods of slope and constant mole. The synergistic extraction complexes with composition(RNH_3Cl)_2·CdCl_2·B have been demonstrated.The synergistic extraction reactions and additional reaction of Cd(Ⅱ)have been proposed as follows: CdCl_2+2RNH_3Cl_(o)+B_(o)(RNH_3Cl)_2·CdCl_2·B_(o) (RNH_3Cl)_3·CdCl_(2(o)+B_(o)(RNH_3Cl)_2·CdCl_2·B_(o)+RNH_3Cl_(o) In addition,the equilibrium constants and the thermodynamic functions of the synergistic ex- traction reactions have been calculated.The IR and NMR spectra of the synergistic ext-ac- tion complexes of Cd(Ⅱ)have been studied as well.

Effect of Flotation Reagents on the Cake Moisture of Copper Concentrate

The effect of reagents used in separating chalcopyrite from pyrite on the cake moisture of the copper concentrate at Daye Iron Mine Mineral Processing Plant was investigated. The results showed that the dosage of lime used for depressing pyrite was the main factor that increased the filter cake moisture of copper concentrate. With increasing the dosage of lime, the cake moisture of copper concentrate increased sharply. The cause was concluded to be the addition of lime to the pulp, which resulted in the formation of floc and a high pH value. The collector Z-200#, used for collecting chalcopyrite, had, as well, an adverse effect on the cake moisture of copper concentrate, but its effect was inferior in respect to that of lime. The cake moisture of copper concentrate can be decreased by changing the method with which lime is added and the pH value of pulp is regulated. The experiment results showed that the sulfuric acid was the best regulator. When the clarified liquor of lime was used as a depressant and the pH value of the pulp was regulated to 6.5€*7.0 by adding sulfuric acid, the cake moisture of copper concentrate was reduced from 15.49% to 13.13%. The examination of chalcopyrite surface by using ESCA (Electron Spectroscopy for Chemical Analysis) showed that calcium sulfate and iron hydroxide had formed on the surface of chalcopyrite when lime was added to the pulp. The formation of calcium sulfate and iron hydroxide on its surface increased the hydrophilicity of chalcopyrite so that its cake moisture increased. The addition of sulfuric acid to the pulp not only removed the calcium sulfate, but also reduced the concentration of iron hydroxide on the surface of chalcopyrite so that the cake moisture of copper concentrate was decreased.

Degradation of Silicone Rubbers in Fenton's Reagents

Gaskets are applied in PEMFCs（proton exchange membrane fuel cells） to keep reactant gases and liquid within their respective regions, which are of great significance for the both sealing and electrochemical performance of fuel cells during the long-term operation. In this study, the degradation of silicone rubbers, often selected as seals in PEMFCs, in Fenton＇s reagents with different H_2O_2 concentrations was investigated. The changes in chemical properties, mechanical behavior and surface morphology of the samples were studied before and after exposure to the test environment over time. It is found that increasing H_2O_2 concentration will degrade the rubbers more severely. The experimental results elucidate the degradation mechanism of silicone rubbers in Fenton＇s reagents and the influence of H_2O_2 in the degradation process.

(Z)-a-Selanyl Alkenyl Grignard Reagents as Convenient Precursors for Stereoselective Synthesis of Trisubstituted Alkenes

Z)-a-Selanyl alkenyl Grignard reagents 2 were prepared conveniently by treatment of a-bromovinylselenides 1 with magnesium filings in THF. Intermediates 2 were reacted with alkyl iodides in the presence of CuI or Pd(PPh3)4 to afford (Z)-1,2-disubstituted vinylselenides 3, which were cross-coupled with Grignard reagents in the presence of (PPh3)2NiCl2 to give trisubstituted alkenes 4 stereoselectively in good yields.

Reaction of Polymer-supported Selenovinyl Bromide with Grignard Reagents: A Facile Route to the Synthesis of (E)-1, 2-Disubstituted Olefins

Polymer-supported selenovinyl bromide, easily prepared from polymer-supported selenenyl bromide with acetylene, reacts with different Grignard reagents using a step-by-step strategy to obtain （E）-1, 2-disubstituted ethenes in good yields.

(Z)-ETHYL 3-BROMO-4,4,4-TRIFLUORO-2-BUTENOATE AS A NOVEL CF_3-CONTAINING BUILDING BLOCK: Its Preparation and Pd-Catalysed Reaction with Alkynes and Organozinc Reagents

A novel CF_3-containing building block, (Z)-ethyl 3-bromo-4,4,4-trifluoro-2-butenoate, was easily prepared from CF_3CBr_3, the former reacted with alkynes Or organozinc reagents in the presence of Pd complexes to afford useful CF_3-containing intermediates in good yield.

ASYMMETRIC SYNTHESIS WITH ORGANO-TITANATE REAGENTS COORDINATED BY TARTARATE-LIKE LIGAND

A series of substituted chiral benzhydrols were synthesized by the reaction of aromatic aldehydes with chiral intermediates formed from chiral titanates and arylmagnesium halides.

Conjugate Addition Reactions of Functionalized Organozinc-copper Reagents to α,β-Unsaturated Esters

Functionalized organozinc reagents can easily conduct 1,4-addition reaction with unsaturated esters in the presence of Cu(OAc)2 and LiCl under very Anld conditions to give the products in excellent yields.

Use of Solid-Supported Reagents towards Synthesis of 2-Arylbenzoxazole, 3, 5-Diarylisoxazole and 1, 3, 5-Triarylpyrazole

Herein we report a convenient and efficient synthesis of 2-Arylbenzoxazole from the Schiff’s bases of 2-Aminophenol, 3, 5-Diarylisoxazole from α, β-unsaturated ketoxime and 1,3,5-Triarylpyrazole from 2-pyrazoline and N-Arylhydrazone by using milder, less toxic and less expensive-NBS-SiO2, KMnO4-Al2O3, PCC-SiO2 and ACC-Al2O3 as solid-supported oxidizing agents at room temperature. Within the framework of Green Chemistry, the use of solid supported reagents has many advantages such as 1) they are easy to remove from reactions by filtration 2) excess reagents can be used to drive the reaction without introducing any difficulties in purification 3) such solid-supported reagents react differently, mostly more selectively, than their unbound counterparts and 4) toxic, noxious and explosive chemicals are handled more safely when contained on solid support.