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March 2, 2011 - Graduate Seminar on Chemistry

Posted on : March 01, 2011

Department of Chemistry
COLLEGE OF SCIENCE AND MATHEMATICS
MINDANAO STATE UNIVERSITY 鈥� ILIGAN INSTITUTE OF TECHNOLOGY

You are cordially invited to a
Graduate Seminar in CHEMISTRY

The Seminar will feature the following topics:

1. UNDESIRABLE SOLVENTS: HOW CAN WE EXORCISE THESE NECESSARY EVILS?
   by Marvin Jose F. Fernandez
   

   Abstract

   Classical organic solvents are often toxic, volatile and expensive to produce and to eliminate. Thus, "solvent-free" green processes have attracted significant attention from synthetic organic chemists as a result of growing environmental concerns. Many reactions are now being designed to proceed cleanly and efficiently in the solid state or under solvent-free conditions. Mild reaction conditions, short reaction times, good to high yields, low cost, easy preparation, and re-usability of catalyst are some of the "green chemistry" advantageous traits of these methods. The use of powerful and efficient computers have also allowed chemists to do theoretical and computational studies on liquid systems. Thus, computational chemistry can also be considered as "green chemistry". Recent articles on this topic will be presented.

2. CONVERTING CO2 TO FUEL: A DREAM OR A CHALLENGE?
   by Ivy L. Librando
   

   Abstract

   It is shown for the first time that using Pt nanoparticles on carbon-based electrodes it is possible to convert CO2 to long carbon-chain hydrocarbons (>C5) at room temperature and atmospheric pressure in a continuous flow cell having the working electrode directly in contact with the CO2 in the gas phase. The performances and product distribution depend on the nature of the electrocatalyst and the reaction conditions. It is also shown that product distribution is different from that expected from Anderson鈥� Schultz鈥揊lory distribution for Fischer鈥揟ropsch synthesis. This step integrates in a photoelectrochemical device to ultimately use solar energy and water to convert back CO2 to fuels.

3. ANTIOXIDANT AND CYTOTOXIC ACTIVITIES OF SOME MARINE SPONGES
   by Anita P. Rivera
   

   Abstract

   The in vitro total antioxidant activity and the cytotoxic activity of hexane, dichloromethane, and ethyl acetate extracts of five species of marine sponges 鈥� Aaptos suberitoides, Dactylospongia elegans, Stylissa massa, Haliclona sp., and an unidentified species coded as KL-05, collected off Misamis Oriental coast, were evaluated. The phosphomolybdenum method for the total antioxidant activity determination showed that all extracts of the five sponge species have varying degrees of antioxidant capacity. Expressed as ascorbic acid equivalents in 渭g/ml of extract, the hexane extract of Dactylospongia elegans (DeH) and the ethyl acetate extract of Aaptos suberitoides (AsE) showed the highest antioxidant capacity of 286 渭g ascorbic acid equivalents at 500 渭g/ml extract concentration while the dichloromethane extract of Dactylospongia elegans (DeD) gave the least activity of 7.5 渭g ascorbic acid equivalents at 25 渭g/ml extract concentration. The ethyl acetate extract of KL-05 (KL-05E) showed no antioxidant capacity in any extract concentration used.

   The brine shrimp assay for cytotoxicity determination indicated very high bioactivity for some species with estimated chronic LC50 of 20 鈥� 30 ppm for HspH & DeD; 50 鈥� 70 ppm for AsE, SmH & SmE; 115 鈥� 300 ppm for DeH, SmD & SmE; and 1,500 鈥� 4,000 ppm for KL-05H, KL-05E & DeE.

   The antioxidant and cytotoxic activities of the marine sponges may be attributed to the zoochemicals present. Adapting the procedure of Edeoga et al for phytochemical analysis, all sponge species contain alkaloids, saponins, tannins and flavonoids. Terpenoids are present only in Haliclona sp.; and the cardiac glycosides, only in Aaptos suberitoides and Haliclona sp.

4. SWITCHABLE SOLVENTS: WHICH SIDE ARE YOU ON?
   by Bren Mark B. Felisilda
   

   Abstract

   Imagine a smart solvent that can be switched reversibly from a liquid with one set of properties to another that has very different properties, upon command. Such solvents are known as 鈥渟witchable solvents鈥�. They are liquids that can be reversibly converted from one form into another, where the two forms differ in their physical properties. One example of such solvent system makes use of a non-ionic liquid (an alcohol and an amine base) that converts into an ionic liquid ( a salt in liquid form) upon exposure to an atmosphere of carbon dioxide, and then reverts back into it鈥檚 non-ionic form when exposed to nitrogen or argon gas. Such switchable solvents should facilitate organic syntheses and separations by eliminating the need to remove and replace solvents after each reaction step.

   This paper will tackle the current status of switchable solvents. It will introduce the present kinds of switchable solvents just like switchable polarity solvents (SPS), switchable-hydrophilicity solvents (SHS) and switchable water. The original switchable solvents, known as SPS switch back and forth between low- polarity form and a high-polarity form, which is triggered by the addition of 1 bar of CO2 (to boost the polarity) and removal of it to drop back to low polarity. However, they had several limitations. One is that they are somewhat water-sensitive. And even the induced polarity change was large enough, a larger polarity was desired. To address the said issues, the two other types of switchable solvents were made.

   Furthermore, some studies involving switchable solvents will be cited in the paper to show the validity of such solvents.

5. DNA DAMAGE AND PROTECTIVE EFFECTS OF BULAKLAK NG PARAISO
   by Christina Y. Loquere
   

   Abstract

   The genotoxic potential of the crude aqueous and methanolic extracts of Ceasalpinia pulcherrima Linn. leaves will be investigated in vivo, using comet assay and micronucleus test, as well the possible protective effects of these extracts against methyl me thanesulfonate (MMS)-induced DNA damage. Albino mice will be grouped according to the following dosage: negative control (distilled water), positive control (MMS), solvent control (DMSO), maximum tolerable dose (MTD), MTD/2, MTD/4, MMS + MTD, MMS + MTD/2 and MMS + MTD/4. Peripheral blood sample will be taken 48 and 24 hours after treatment for comet assay and micronucleus test, respectively.

   Prior to the assays, qualitative phytochemical screening of the extracts was done using the standard method of Abulude and Singh, et al. The screening revealed the presence of carbohydrates, resin, glycosides, anthraquinone, saponins, flavonoids, sterols, steroids, tannins and phenols. Phlobatannins, alkaloids and terpenoids were absent.

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