Sustainable Graphene Oxide Support for Ruthenium Catalysts to Improve the Efficiency of the Hydrodesulfurization of Thiophenes
沙烏地阿拉伯 is the largest oil exporter in the world. 64,000,000 tons of sulfur oxides are produced every year through the combustion of organic sulfur compounds in the oil industry. This leads to several environmentally serious problems, including air pollution. This research provides a novel strategy to utilize natural-based Graphene Oxide (GO) as a support for ruthenium (Ru/GO) to functionalize as a green catalyst for hydrodesulfurization. Physical activation of camel bone samples was carried out by carbonizing them at 500oC to produce camel bone charcoal. Modified hammer’s method was employed for GO production, followed by doping of ruthenium in a simple synthesis step. The prepared catalyst has been characterized by XRD, SEM and EDX techniques. Thiophene and 3-methylthiophene were used as model compounds in the hydrodesulfurization process. The catalytic reactions were carried out at atmospheric pressure in a continuous up-flow fixed-bed quartz reactor. The composition of the sulfur containing gaseous products was analyzed by gas chromatography. The product distribution achieved for thiophene was 3-6% butadiene and 76-77% butane. And for 3-methylthiophene, it was 32.3% of pentaned 1-pentene and 2-pentene and the selectivity percentage was 45%. Ru/GO has been found to be an excellent catalyst of thiophene and 3- methylthiophene hydrodesulfurization and is a considerable improvement when compared to the commercially available catalysts. The prepared catalyst shall potentially lead to the reduction of sulfur pollution in the future. The positive effect on the environment could be substantial.
Difluoromethylation of arylidene Meldrum's acid derivatives
Fluorine-containing compounds gained significant attention during the past decade1. About 20% of novel pharmaceuticals and 40% of novel agrochemicals every year contain at least one fluorine atom in the molecule. For a long time the most frequently used was trifluoromethyl group, but nowadays the most promising is the chemistry of partially-fluorinated groups. For example, the difluoromethyl substituent (CHF2) exhibits unique pharmacoforic properties capable of serving as lipophilic hydrogen bond donor thus being bioisosteric to hydroxyl group2. There are several general approaches for the formation of a required fluorinated fragment, one of them is direct nucleophilic fluoroalkylation. This approach is well-developed for trifluoromethylation reactions, such as addition of CF3-anion equivalents to C=O, C=N and electron-deficient C=C bonds or metal-catalyzed substitution in haloarenes3. However the similar difluoromethylation processes are still quite challenging. Herein we present a novel and convenient protocol for the synthesis of β-CF2H functionalized carbonyl compounds and carbinols by nucleophilic difluoromethylation of electron-deficient olefines. The process is based on a 1,4-addition of in situ generated4 phosphorus ylide Ph3P=CF2 2 to the arylidene Meldrum's acid conjugates 1. The resulting phosphobetaines 3 are hydrolized/protodephosphorilated without isolation, giving β-CF2H substituted carboxylic acids 4. The latter may be easily transformed to the corresponding ethers 5 and alcohols 6 without preliminary purification.
First photochromic diarylethenes with cyclohexenone ethene "bridge"
Photochromism is determined as reversible transformation between two chemical species, induced by action of light [1]. Herewith, initial form and photoinduced isomer have different properties, first of all, spectral. The phenomenon is attractive for the design of hi-tech materials for different applications, including optical memory elements and molecular switches. Diarylethenes are the most promising class of organic photochromic compounds due to outstanding thermal stability of both isomers and high photostability [2, 3]. Photochromism of diarylethenes explained by reversible electrocyclic reaction of hexatriene system, provoked by UV light, back reaction is induced by visible light. In this work we have proposed a new class of photochromic diarylethenes with cyclohexenone ethene “bridge” 4. The key stage of the synthesis is “one-pot” reaction of ketoesters 1 and chalkones 2 in ethanol in the presence of sodium ethoxide that includes Michael reaction and subsequent intramolecular condensation of the resulting product. The final decarboxylation of semi-product 3 results in target diarylethenes 4. We have prepared a wide range of photochromic diarylethenes with thiophene, oxazole, imidazole and benzene derivatives as aryl moieties. The spectral characteristics of compounds obtained have also been discussed.
H.E.L.P. Heart Empowers Lifelong Pacemaker
EXPERIMENT 1---The effect of NaCl and Glucose Concentration on the efficiency of the cell I. Introduction Experiment on different concentrations of standard glucose solution (ranged from 0.125 M to 1.000 M) and standard sodium chloride solution (ranged from 0.250 M to 4.000 M) were done. We investigated the full concentration effect, which included both concentration of glucose solution and sodium chloride solution on the fuel cell’s output voltage, current and power. II. Procedures 1. Add 25.0 cm3 of Glucose solution of the tested concentration to the beaker representing the anode, and add 25.0 cm3 of distilled water to the beaker representing the cathode. 2. Add 50.0 cm3 of 0.250 M NaCl (aq) to both beakers representatively. 3. Fold a piece of filter paper and soak in fully into NaCl (aq) at cathode. 4. Clean and place the silver wires into the beakers representatively, and connect the air pump to the cathode. 5. Connect the cell to two multi-meters, each acting as a voltmeter and an ammeter respectively 6. Take the readings of multi-meters after 30 seconds. 7. Repeat steps 1 to 6 twice for the second and third reading of the cell. 8. Take average value among three values as the final reading of the cell. 9. Repeat steps 1 to 8 by replacing the NaCl (aq) with concentrations of 0.000 M, 0.500 M, 1.000 M, 2.000 M and 4.000 M, and the standard glucose solution with concentrations of 0.000 M, 0.125 M, 0.250 M, 0.500 M, 0.750 M and 1.000 M. III. Result of Experiment 1 When glucose concentration is increased from 0.000 M to 0.250 M, the output power increases, it is found that power generated is maximized at glucose concentrations between 0.125 M and 0.250 M. However, with further increase in glucose concentration from 0.250 M to 1.000 M, the power generated decreases. This shows that high concentration of glucose inhibits the generation of electricity, while higher concentration of sodium chloride solution can increase the output. EXPERIMENT 2---The effect of temperature on the efficiency of the cell I. Introduction In this experiment, the second effect - temperature on the fuel cell’s output voltage, current and power was investigated. In order to get a significant result, the effect of temperature on these measures with fixed 0.250 M glucose solution and sodium chloride solution concentrations varied from 0.500 M to 4.000 M had been investigated. II. Procedures 1. Add 25.0 cm3 of Glucose solution of the tested concentration (0.25 M) to the beaker representing the anode, and add 25.0 cm3 of distilled water to the beaker representing the cathode. 2. Add 50.0 cm3 of 0.500 M NaCl (aq) to both beakers representatively. 3. Fold a piece of filter paper and soak in fully into NaCl (aq) at cathode. 4. Clean and place the silver wires into the beakers respectively, and connect the air pump to the cathode. 5. Connect the cell to two multi-meters, each acting as a voltmeter and an ammeter respectively 6. Take the readings of multi-meters after 30 seconds. 7. Repeat steps 1 to 6 twice for the second and third reading of the cell. 8. Take average value among three values as the final reading of the cell. 9. Repeat steps 1 to 8 by varying the temperature from 42℃ to 32℃. 10. Repeat steps 1 to 9 by replacing the NaCl solution of 0.000 M, 1.000 M, 2.000 M, and 4.000 M respectively. III. Result of Experiment 2 The results showed a consistent trend and relationship of the effect of temperature on the output current, voltage and power of the fuel cell for 4 different concentrations of sodium chloride solution with fixed 0.25 M glucose solution. Generally, the results showed that the output power increases with temperature. EXPERIMENT 3---The effect of dialysis tubing and Nafion 117 on the efficiency of the cell I. Introduction Semi-permeable membrane separating glucose and oxygen, ensure the glucose oxidation only occurs at the anode, and preventing glucose oxidation occurs at the cathode, responds to maximize power output. Experimental study on two kinds of membranes, dialysis membranes and Nafion 117 films were done, by studying their fuel cell output voltage, current and power effects. Previous experiments showed that the optimal output of the battery is at 0.250 M glucose solution, Therefore, experimental conditions for glucose concentration is fixed on 0.250 M and sodium chloride solution concentration varies from 0.500 to 4.000 M. II. Procedures The Effect of Dialysis Tubing on voltage and current of the fuel cell 1. Pour 50 cm3 1.000 M NaCl (aq) to each compartment of the beaker separated by dialysis tubing. 2. Pour 0.250 M Glucose Solution into the compartment representing anode. 3. Connect the cell to two multimeters, which act as a voltmeter and ammeter respectively 4. Take the reading of the multimeters after 30 seconds 5. Repeat steps 1 to 4 twice for the second and third reading of the cell. 6. Take average value among three values as the final reading of the cell. 7. Repeat steps 1 to 6 with NaCl (aq) with concentration of 0.000 M, 0.250 M, 0.500 M, 2.000 M and 4.000 M to obtain the remaining data. The Effect of Nafion 117 on voltage and current of the fuel cell 1. Add 50 cm3 1.000 M NaCl (aq) and 50 cm3 of 0.250 M of glucose solution to the beaker. 2. Add 1.000 M NaCl (aq) to the Nafion 117 membrane pouch, and silver plate was put inside to become the anode. 3. Connect the cell to two multimeters, which act as a voltmeter and ammeter respectively 4. Take the reading of the multimeters after 30 seconds 5. Repeat steps 1 to 4 twice for the second and third reading of the cell. 6. Take average value among three values as the final reading of the cell. 7. Repeat steps 1 to 6 with NaCl (aq) with concentration of 0.000 M, 0.250 M, 0.500 M, 2.000 M and 4.000 M to obtain the remaining data. III. Result of Experiment 3 The result had shown that when the solution does not contain glucose (i.e. Glucose concentration equals to 0.000 M), Nafion 117 Membrane Cells have similar power outputs compared to the dialysis tubing cells. However, in 0.250 M glucose solution, the output of Nafion 117 membrane cell is about 1 to 5 times more compared to that of dialysis tubing cell. According to the experiment results, it was found out that the power output was maximized when the concentration of glucose solution and NaCl (aq) are 0.250 M and 4.000 M respectively. Under this concentration, the out of Nafion 117 membrane cell was 1336.68 nW which was 5 times higher than that of dialysis tubing cell. Hence, adopting Nafion 117 as the selectively membrane can greatly enhance the output of cell. It is believed that the special structure of Nafion 117 has limited the movement of glucose molecules, and prevented their oxidation at cathode. This has enhanced the oxidation of glucose at anode, and thus increased the power output of the cell.
Interaction of the unsaturated sulfones with azinium ylides
1. Introduction In Japan the energy self-efficiency is very low: only 6%. Hydrogen (H2) has been expected as a new and alternative energy source to imported one, such as petroleum resources. Now hydrogen energy comes into the practical use in the field of the fuel cell. Hydrogen must be extracted from other sources, for example, water, fossil fuel, and so on. Hydrogen is obtained from water by using electronic or thermal or photo energy in most cases, whereas it is well-known that hydrogen is given by the oxidation reaction of silicon in alkaline aqueous solution: Si + 2OH- + H2O → SiO32- + 2H2 Free silicon (Si) is not only used in the steel refining, aluminum-casting in the field of fine chemical industries but also is used as a material in semiconductor electronics. However, a lot of used silicon is thrown away as a waste, being not reused and recycled. In this study we try to apply a waste silicon to obtain hydrogen based on the above reaction. The purpose of the study is to develop a safe and convenient manufacturing method to generate hydrogen for an energy source of the fuel cell.