Hydrodehalogenation of hexachloro- and hexabromobenzene by metallic calcium in ethanol, in the presence of Rh/C catalyst.

Both hexachlorobenzene and hexabromobenzene were successfully hydrodehalogenated to the monohalogenated derivative and ultimately to benzene (which was subsequently reduced to cyclohexane) using a mixture of metallic Ca, ethanol, and Rh/C, by simple stirring in diethyl ether, at room or mild temperature (60 °C). Various experiments were performed in order to assess the role of the solvent and Rh/C catalyst, as well as for elucidating the reaction pathway.

Considerations on the mechanism of Ca/ethanol/Pd/C assisted hydrodechlorination of chlorinated aromatic substrates.

In order to elucidate the metal-alcohol hydrodechlorination reaction mechanism, several experiments using chloroanisoles as substrates were performed. Thus, chloroanisoles were stirred at 60 °C for 2 h with a mixture of Ca, methanol and various reduction catalysts. The use of deuterated methanol and zeta potential experiments offered supplementary informations, pointing toward a probable radicalic mechanism that occurs on Ca and Pd/C surfaces.

Detection of influenza virus by a biosensor based on the method combining electrochemiluminescence on binary SAMs modified Au electrode with an immunoliposome encapsulating Ru (II) complex.

Recently, point of care testing (POCT) used for diagnosis of influenza infection has a problem showing false negative diagnosis because of the low sensitivity. We would like to report detection of influenza virus A (H1N1) by an immunosensor based on electrochemiluminescence (ECL) that uses an immunoliposome encapsulating tris(2,2'-bipyridyl)ruthenium(II) complex. By using the sensor, we could detect the virus that competed with hemagglutinin (HA) peptide immobilized on self-assembled monolayers (SAMs) in immunoreaction of the antibody bound on the surface of liposome. The HA peptide was 19 mer (TGLRNGITNKVNSVIEKAA). We demonstrated great improvement of sensitivity and accuracy by introducing binary SAMs instead of mono SAMs. The binary SAMs was prepared from 3,3'-dithiodipropionic acid and 1-hexanethiol. Use of the binary SAMs enabled to increase the SAMs coverage on Au electrode; the fact was confirmed by observation of the cathodic desorption currents. By using such an electrode, first the detection method of BSA was optimized to lower ECL background signal. Then we applied the method to the detection of influenza virus. We could successfully detect the virus with higher sensitivity compared with that by POCT and ELISA. The detection range was from a concentration of 2.7 × 10(2) to 2.7 × 10(3) PFU/mL.

Mechanochemical degradation of chlorinated contaminants in fly ash with a calcium-based degradation reagent.

This report presents our results in a low-temperature mechanochemical hydrodechlorination process applied to fly ash coming from a municipal waste incinerator in order to efficiently remove all traces of PCDDs, PCDFs and PCBs. We found that the most suitable degradation agent is a mixture of metallic calcium and calcium oxide. A sample of fly ash presenting a TEQ of 5200 pg g(-1) was completely detoxified (no traces of PCDDs, PCDFs and PCBs detected) after ball-milling at 400 rpm over night.

A flow-through electrochemiluminescence sensor for salt stress on rice plants.

Cultivation of rice plants (Koshihikari, IR4595 and IR28) in 250 mmol/L NaCl over 16 days provided interesting profiles of responses on a flow-through electrochemiluminescence (ECL) system with tris(2,2'-bipyridine)ruthenium complex. Although some time lags were noted among these rice plants, the increment in the ECL responses was clearly observed on the 11th day. The obtained ECL response profiles were consistent with the proline profiles obtained by HPLC. Such consistency demonstrated that the present ECL system would find a utility as a useful sensor for salt stress on rice plants.

Metallic Ca-Rh/C-methanol, a high-performing system for the hydrodechlorination/ring reduction of mono- and poly chlorinated aromatic substrates.

We investigated the reduction of some substituted mono- and poly chlorobenzenes bearing functional groups such as methyl, methoxy, hydroxyl, and amino, under mild conditions (80 degrees C and magnetic stirring, for 2 h) using a system consisting of metallic calcium and methanol (as hydrogen donor system) and 5% wt. Rh/C (as hydrodechlorination/ring reduction catalyst). Hydrodechlorination easily took place for methoxy- and alkyl-chlorobenzenes, yielding the corresponding hydrodechlorinated compounds (57-76%) and affording as secondary reaction products the ring-reduced compounds (16-43%). Treatment of hydroxy- and amino-chlorobenzenes under the same conditions, respectively, gave corresponding hydrodechlorinated compounds (over 60%) along with the ring-reduced compounds. Results show that the reaction of substituted polychlorinated benzenes needs a longer reaction time (6 h), the transformation being nevertheless complete.

Highly effective degradation of polychlorinated biphenyls in soil mediated by a Ca/Rh bicatalytic system.

Treatment of PCBs in soil using metallic calcium and alcohol ultimately reduced 1300 x 10(-3)mgkg(-1) PCB concentration to 1.8 x 10(-3)mg kg(-1). Moreover, using the metallic calcium catalyst method to promote the effective use of hydrogen gas in the presence of a specific reducing catalyst such as Rh/C, the decomposition efficiency of PCBs was notably increased despite mild reaction conditions. The total PCB concentration of treated soils decreased from 1300 x 10(-3)mg kg(-1) to 0.62 x 10(-3)mg kg(-1) (decomp. avg.=99.95%). Treatment of soils with metallic calcium and a Rh/C catalyst in alcohol under mild conditions such as 0.15-0.26 MPa at room temperature is extremely effective for degradation of existing PCBs.

Attomole detection of hemagglutinin molecule of influenza virus by combining an electrochemiluminescence sensor with an immunoliposome that encapsulates a Ru complex.

An immunoliposome (80 nm in diameter) encapsulating a Ru complex with two aminobutyl moieties was prepared to detect the presence of hemagglutinin molecules, which play an important role in influenza virus infection. The highly sensitive detection was accomplished by electrochemiluminescence (ECL) from the Ru complex adsorbed onto Au electrodes after competitive immunoreactions. This method clarified that the adsorption of the Ru complex onto the electrode was an important factor in obtaining high sensitivity. Optimization of the analytical conditions enabled determination of the hemagglutinin molecules of the influenza virus in the concentration range of 3 x 10(-14) (6 x 10(-19) mol/50 microL sample) to 2 x 10(-12) g/mL. The sensitivity was far superior to that obtained by conventional ELISA as well as to that obtained by biosensors and reported thus far.

Calcium-promoted catalytic degradation of PCDDs, PCDFs, and coplanar PCBs under a mild wet process.

The authors achieved highly efficient degradation of polychlorinated aromatic compounds, including polychlorinated dibenzo-p-dioxins, dibenzofurans, and dioxin-like compounds such as coplanar polychlorinated biphenyls (co-PCBs), which are known as persistent organic pollutants. Degradation was accomplished in 24 h through a simple stirring operation using safe and high workability metallic calcium, which acts as both a scavenger and a reducing agent, and Rh/C catalyst in an alcohol solution under mild conditions in a sealed tube at 25 degrees C without a temperature increase within 0.15 MPa of increasing internal pressure during the reaction. In this system, reductive dechlorination by metallic calcium and catalytic reduction by Rh/C and generated hydrogen gas, without any external addition of hydrogen, exert a synergistic effect on the degradation of chlorinated compounds. Alcohol was used as a proton source and hydrogen, which was generated by a side reaction, causes an increase in the activity of Rh/C catalyst. Through the degradation of 4-chloroanisole in ethyl alcohol, anisole and cyclohexyl methyl ether were obtained in good conversions. Using ethyl alcohol as a solvent, treatment of dioxins and co-PCBs in a solution was markedly effective for degradation to reduce 2806 pg TEQ/ml of initial concentration to 31.8 pg TEQ/ml; its yield was 98.5%. Moreover, degradation in methyl alcohol took place in a 99.3% yield. That concentration ultimately reached 20.3 pg TEQ/ml under a mild wet process. All congeners of dioxins and co-PCBs were degraded in high conversions. In this degradation, lower aliphatic alcohol, such as methyl alcohol, is effective for making a new calcium surface as compared to alcohol with more methylene chains. In addition, it seemed that a higher pressure of hydrogen was easily generated in methyl alcohol, and then catalytic degradation was effectivley influenced.

Approach to highly efficient dechlorination of PCDDs, PCDFs, and coplanar PCBs using metallic calcium in ethanol under atmospheric pressure at room temperature.

Detoxification of highly toxic polychlorinated aromatic compounds such as polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and dioxin-like compounds such as coplanar polychlorinated biphenyls (co-PCBs) under mild conditions (atmospheric pressure and room temperature) was achieved by a simple stirring operation for 24 h using metallic calcium in ethanol, without any tedious decomposition procedures and harsh conditions such as high temperature and/or high pressure. Metallic calcium can be kept stable under atmospheric conditions for a long period as compared to metallic sodium since the surface is coated with CaCO3, which is formed in the contact with air. Moreover, ethanol, which is one of the safest solvents for humans, acts not only as a solvent but also as an accelerator due to its ablility to remove the carbonated coating. This decomposition method for PCDDs, PCDFs, and co-PCBs therefore is one of the most economical and environmentally friendly detoxification methods with respect to the input energy and safety of reagents used. Concentration for each isomer of PCDDs, PCDFs, and co-PCBs was reduced in 98.32-100% conversions by treatment in ethanol at room temperature. The toxicity equivalency quantity (TEQ), which was measured by the HRGC-HRMS analysis, for the total residues of isomers was reduced from 22,000 to 210 pg TEQ/mL of hexane (conversion: 99.05%) at room temperature. By refluxing over 24 h, the conversion increased up to 99.45%.

Elimination of ingredients effect to improve the detection of anti HIV-1 p24 antibody in human serum using SPR apparatus.

Highly sensitive detection of proteins in serum becomes difficult in some cases during surface plasmon resonance (SPR) measurements, because some ingredients in the serum hugely enhance non-specific reactions on the sensing chip of SPR. It is well recognized that the antibody against core protein p24 of HIV in serum is one of the most important proteins in the accurate diagnosis of infection with HIV. In this study, we could attain the accurate detection of anti p24 antibody in human serum by eliminating the serious effects of the ingredients in serum on the measurement of SPR by employing these procedures: 1) blocking the gold surface of the sensing chip with human serum and 2) heating the serum sample at 56 degrees C for 30 min. Without these treatments, the signal of SPR was considerably suppressed on the measurements of the anti p24 antibody which contained human serum, making the accurate detection difficult. However, with introducing the above two treatments, the sensing of anti p24 antibody in human serum was improved, while a small non-specific reaction was still observed. By removing the non-specific reaction caused by the ingredients in the serum, we could accurately measure the antibody for p24 in human serum sample over the range from 1 to 20 micrograms/ml.

Quadruple Decker [3.3][3.3][3.3]Orthocyclophane Acetal-An Orthocyclophane Ladder.

Through clever bridging of orthocyclophanes (in this case by acetalization), molecules such as 1 can be formed with four benzene rings in a stacked face-to-face arrangement. UV/Vis spectroscopic and electrochemical properties of 1 are governed by π-π through-space interactions within the molecule.