Sharif Digital Repository

Dehydrogenation of C10-C14 normal paraffins on Pt/alumina catalyst is a reaction of prime importance particularly to the detergent industry for the manufacture of the active ingredients. In this thesis, the modifying effect of Zn, Li, K, and Mg on the activity and selectivity of the Pt-Sn/γ-Al2O3 dehydrogenation catalysts were investigated. The catalysts were prepared by co-impregnation, characterized by TPR, BET, SEM, EDAX and XRD techniques and tested in a tubular reactor. Zinc reduced the activity of Pt-Sn alloy and hence reduced the catalyst activity in the dehydrogenation reaction and enhanced its selectivity to normal mono olefins. The addition of Li, K, and Mg to Pt-Sn/γ-Al2O3... 

Highly active unsupported MoO3 and (Co) MoO3 catalysts were synthesized utilizing the solution combustion method where the Ammonium molybdate powder and an organic additive were used as precursors. Different organic materials including Ethylene Diamin Tetra-acetic acid (EDTA), Polyethylene Glycol 200 (PEG 200), Sorbitol and Urea were used as additive in order to investigate the effect of additive structure on morphology and particle size of products. Also various reaction parameters such as the additive/Mo molar ratio, concentration of metal ion in solution, pH of the reaction and temperature of the synthesis media were changed to study effects on product morphology and size. Outcomes were... 

In this study thermodynamics and kinetics effects of two ionic liquids (ILs) on the formation and dissociation of methane and carbon dioxide hydrates were investigated. The ILs used in this study are 1-butyle-3-metylimidazolium tetrafluoroborate, [Bmim][BF4], and 1-butyle-3-metylimidazolium methyl sulfate, [Bmim][MS]. At the first step of experimental section, the tetrahydrofuran (THF) was used in atmospheric pressure. The structure of THF hydrate is similar to natural gas hydrate; therefore it is used as a model for studying the properties and investigation of inhibitors effects on gas hydrates. In order to consider the effects of foregoing ILs on the formation and dissociation of gas... 

Liquide phase catalytic exchange (LPCE) between liquid water and hydrogen is an important reaction for separation of the hydrogen isotope from liquid water. One of the application of this reaction is heavy water production. This method is mainly used hydrophobic catalysts with Pt active metal. The use of hydrophobic catalyst is necessary, because liquid water in the LPCE reaction, resulted in block the catalyst pores and loss of catalyst activity. Design of experiment has been done by using of Design Expert 7.0.0 for determination of number of tests and optimization of Pt weight percent. Alumina and carbon (included graphene, single-walled and multi-walled carbon nanotube) supported 5% wt Pt... 

According to the importance of conversion and transmission of energy, and introduction of hydrate formation process as an alternative method, in this study, the nano-graphene oxide is used to increase the rate if methane gas hydrates formation. The experiments were performed at different concentrations of 30 to 70 ppm and the results were compared with pure water. The effect of temperature and pressure on hydrate formation at temperatures of 1 and 2˚C and pressures of 48 and 53 bar were studied. And it was found that nano-graphene oxide can be used to accelerate the methane hydrates formation. The effect of ultrasonic on methane hydrate formation has been studied that it was found that the... 

In this research, some inhibitors based on quaternary monoammonium salts and quaternary diammonium salts containing different anions were synthesized to prevent formation of methane gas hydrates, and they were characterized using 1H and 13C NMR spectra, IR spectroscopy, elemental analysis and mass spectrometry. Then, the synthesized compounds were used in an autoclave under 128 bar pressure under controlled isothermal conditions to determine retention time considering displacement amount of the gas hydrate temperature- pressure chart and also to determine subcooling of the samples using HW Hydrate software. According to the results T3, T4 and TBAHF compounds in their pure form, not only... 

Different catalysts have been proposed for CO oxidation reaction and still many researches are performed to obtain a catalyst with high activity and stability. In this study, MOFs of CuBTC, MIL-101(Cr), and NH2-MIL-101(Cr) and active metal of Pd have been selected and their performances have been investigated in CO oxidation reaction. MOFs have been synthesized by hydrothermal method. Pd loading has been performed by impregnation method in various pH and in aqeous palladium nitrate solution and palladium nitrate solution in nitric acid. To reveal the effect of the nature of noble metal, activity of 1% Pt/MIL has been investigated. Amine-functionalized MIL-101(Cr) has been synthesized by... 

Enzymes are an important part of detergents, they reduce the activation energy of the reaction and thus increase the efficiency of the process. Protease enzyme is one of the most common enzymes in detergents. Bacillus strain is the most important strain in the production of this enzyme and among the species of Bacillus, Bacillus subtilis is the most used. Bacillus subtilis is a gram-positive, rod-shaped bacterium. This bacterium is considered a non-pathogenic cell that has the ability to form spores and prevent death and damage in harsh conditions. In this study, CRISPR system was used to modify the genome of Bacillus subtilis ATCC 6633 in order to increase alkaline protease. To increase the... 

According to the reports of the Tehran Air Quality Control Company, mobile sources are responsible for the emission of 70-85% of air pollutant in this metropolis. Over the past decades, compressed natural gas (CNG) is known as a cleaner fuel and a suitable alternative to gasoline and diesel fuels in the transportation section in some countries. However, methane emissions from natural gas vehicles is a significant challenge because it is a potent greenhouse gas and plays important role in global warming. In addition, because of another pollutant emissions from these vehicles, exhaust gas treatment is a crucial issue. Using Three-Way catalysts (TWC) is the conventional method in order to... 

Industrial enzymes can generally be classified into three groups: carbohydrases, proteases and lipases, which account for a major part of the global enzyme trade. Proteases, in particular, have always been extensively studied and investigated due to their widespread use in various industries, such as food, pharmaceutical, chemical, and agricultural sectors. Proteases are a group of proteolytic enzymes that break down proteins and peptides into their constituent amino acids by hydrolyzing peptide bonds. Among the family of proteases, alkaline serine proteases have special biocatalytic abilities in both aqueous and organic environments. Their suitable resistance in alkaline environments and... 

The selective oxidation of H2S into elemental sulfur is a complementary desulfurization method for reducing H2S emissions from gas streams. Several studies have been conducted in recent years to develop active, selective, and stable catalysts. The purpose of this research is to develop a catalyst with high activity and selectivity that is suitable for the gas output of one of the country's refineries. For this purpose, three supports of mixed metal oxide (solid solution), Ce-Al, Ce-Si, and Ce-Zr with a molar ratio of 1:2 (ceria: metal) were made by the co-precipitation method. In the following, three samples named 10V-CeAl, 10V-CeSi, and 10V-CeZr were prepared by impregnating 10% wt vanadium...