Pilot-scale test on electron beam treatment of municipal solid waste flue gas with spraying slaked-lime slurry

Simultaneous removal of NO_x, SO₂ and HCl in flue gas of a municipal solid waste incinerator was studied by using electron beam irradiation technology. The flue gas around of 1000 Nm³/h was led to a spray-dryer-type reactor from an inlet of ESP of the municipal waste incinerator by spraying slaked-lime slurry with one or more stoichiometic amount of the pollutants, concentrations of HCl (400 ppm) and SO₂ (50 ppm) decreased almost completely, while concentrations of NO_x (100 ppm) were markedly decreased to about 20 ppm by electron beam irradiation with a dose of 10 kGy at 150°C under spraying slaked-time slurry of two stoichiometric amounts. The removal of NO_x was improved by increasing the dose and the amount of spraying slaked-time slurry, and by lowering the irradiation temperature.     

On the antioxidant mechanism of curcumin: classical methods are needed to determine antioxidant mechanism and activity

[reaction: see structure] The antioxidant activity of curcumin (1, 7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione) was determined by inhibition of controlled initiation of styrene oxidation. Synthetic nonphenolic curcuminoids exhibited no antioxidant activity; therefore, curcumin is a classical phenolic chain-breaking antioxidant, donating H atoms from the phenolic groups not the CH(2) group as has been suggested (Jovanovic et al. J. Am. Chem. Soc. 1999, 121, 9677). The antioxidant activities of o-methoxyphenols are decreased in hydrogen bond accepting media.     

Partitioning of clay colloids at air-water interfaces

Colloid sorption onto air-water interfaces in a variety of natural environments has been previously recognized, but better quantification and understanding is still needed. Affinities of clay colloids for the air-water interface were measured using a bubble-column method and reported as partition coefficients (K). Four types of dilute clay suspensions were measured in NaCl solutions under varying pH and ionic strength conditions: kaolinite KGa-1, illite IMt-2, montmorillonite SWy-2, and bentonite. The K values of three types of polystyrene latex particles with different surface-charge properties were also measured for comparison. Kaolinite exhibited extremely high affinity to the air-water interface at pH values below 7. Illite has lower affinity to air-water interfaces than kaolinite, but has similar pH dependence. Na-montmorillonite and bentonite clay were found excluded from the air-water interface at any given pH and ionic strength. Positively and negatively charged latex particles exhibited sorption and exclusion, respectively, at the air-water interface. These results show the importance of electrostatic interactions between the air-water interface and colloids, especially the influence of pH-dependent edge charges, and influence of particle shape.     

Kinetic resolution of axially chiral 2,2'-dihydroxy-1,1'-biaryls by palladium-catalyzed alcoholysis

Palladium-diamine complexes catalyzed kinetic resolution of axially chiral 2,2'-dihydroxy-1,1'-biaryls by alcoholysis of vinyl ethers. The reaction proceeded with high selectivity for various kinds of biaryls. This process is applicable to not only binaphthols but also biphenols, which have been considered to be difficult for the enantioselective synthesis by known catalytic methods.     

Structural factors for the formation of propellane-type products in the solvolysis of bicyclic bridgehead compounds

Methanolyses of 2-oxobicyclo[3.3.1]non-1-yl triflate, 3, 3-dimethyl-2-oxobicyclo[3.3.1]non-1-yl triflate, and 2-oxobicyclo[4. 3.1]dec-1-yl mesylate gave the corresponding propellanone in 12%, 20%, or 3.2% yield, respectively, beside substitution or rearranged products under typical conditions. No propellane-type product was obtained in the solvolyses of 1-bromobicyclo[3.3.1]nonane, 2-methylidenebicyclo[3.3.1]non-1-yl heptafluorobutyrate, and 3, 3-dimethyl-2-thioxobicyclo[3.3.1]non-1-yl tosylate. The factors that permit the formation of the propellane-type product from the intermediate bridgehead cations are examined with the aid of theoretical calculations at PM3 and B3LYP/6-31G.     

Palladium-catalyzed oxidation of cyclohexanones to conjugated enones using molecular oxygen

Oxidation of cyclohexanones into conjugated enones with molecular oxygen as oxidant was achieved by palladium catalysts. A catalyst system consists of 1 mol % Pd(OCOCF₃)₂ and 5,5′-dimethyl-2,2′-bipyridine accomplished maximum 84% yield for the oxidation of cyclohexanone and 51-78% yields for 4-substituted-cyclohexanones.     

Rhodium-catalyzed asymmetric 1,4-addition of aryltitanium reagents generating chiral titanium enolates: isolation as silyl enol ethers

The addition of aryltitanium triisopropoxide (ArTi(OPr-i )3) to alpha,beta-unsaturated ketones proceeded with high enantioselectivity (94-99.8% ee) in the presence of 3 mol % of [Rh(OH)((S )-binap)]2 in THF at 20 degrees C to give high yields of the titanium enolates as 1,4-addition products. The titanium enolates were converted into silyl enol ethers by treatment with chlorotrimethylsilane and lithium isopropoxide.     

A powerful,novel, multiplex typing system for six short tandem repeat loci and the allele frequency distributions in two Japanese regional populations

A new multiplex system for six tetranucleotide short tandem repeat (STR) loci was devised based on multicolor dye technology. Six loci (D20S480, D6S2439, D6S1056, D9S1118, D4S2639, and D17S1290), each with high discriminating power (each unbiased estimates of expected heterozygosity, Exp. Hz, > 0.80 in a preliminary test), were selected from more than 100 tetranucleotide STRs included in a commercially available primer set. These loci were also selected so as not to link with general STRs in commercially released kits including the combined DNA index system (CODIS) 13 core STRs. The primers were newly designed in the present study, in which each amplicon size had a range of less than 200 base pairs (bp), in order to genotype from highly degraded template DNA. Using this system, we genotyped 270 Honshu (mainland)-Japanese and 187 Okinawa-Japanese. From these allele frequencies, we performed three tests, a homozygosity test, a likelihood ratio test and an exact test for Hardy-Weinberg equilibrium (HWE), and no significant deviations (p < 0.05) from HWE were observed. We also compared the allele distributions at six STRs between both populations, and they were significantly different (p < 0.05) at three loci (D6S2439, D9S1118 and D4S2639). Furthermore, the Exp. Hz and the power of discrimination (PD) at all loci in the Honshu-Japanese population were higher than 0.80 and 0.93, respectively. These statistical values for discriminating power in the Honshu-Japanese were almost the same as in the Okinawa-Japanese. This novel, multiplex polymerase chain reaction (PCR) amplification and typing system for six STR loci thus promises to be a convenient and informative new DNA profiling system in the forensic field.     

Enantioselective Trichloromethylation of MBH‐Fluorides with Chloroform Based on Silicon‐assisted C−F Activation and Carbanion Exchange Induced by a Ruppert–Prakash Reagent

Enantioselective trichloromethylation of Morita–Baylis–Hillman (MBH)‐type allylic fluorides with chloroform (HCCl₃) under organocatalysis was achieved with high to excellent enantioselectivities. Silicon‐assisted C?F bond activation by a Ruppert–Prakash reagent and direct activation of HCCl₃ by a carbanion exchange process with trifluoromethyl (CF₃) carbanion generated in situ from the Ruppert‐Prakash reagent realized the direct asymmetric trichloromethylation at a stereogenic allylic positon, without any help from transition metal catalysis, and under very mild conditions. Pre‐activation of HCCl₃ was not required. This method was extended to the direct enantioselective introduction of other C?H compounds such as alkyne, arene, indene, and FBSM without any pre‐activation under a metal‐free system.     

Asymmetric Desymmetrization via Metal‐Free C−F Bond Activation: Synthesis of 3,5‐Diaryl‐5‐fluoromethyloxazolidin‐2‐ones with Quaternary Carbon Centers

We disclose the first asymmetric activation of a non‐activated aliphatic C?F bond in which a conceptually new desymmetrization of 1,3‐difluorides by silicon‐induced selective C?F bond scission is a key step. The combination of a cinchona alkaloid based chiral ammonium bifluoride catalyst and N,O‐bis(trimethylsilyl)acetoamide (BSA) as the silicon reagent enabled the efficient catalytic cycle of asymmetric C_sp3?F bond cleavage under mild conditions with high enantioselectivities. The ortho effect of the aryl group at the prostereogenic center is remarkable. This concept was applied for the asymmetric synthesis of promising agrochemical compounds, 3,5‐diaryl‐5‐fluoromethyloxazolidin‐2‐ones bearing a quaternary carbon center.