Sharif Digital Repository

In the dairy industry, for the processing of raw milk, including the isolation of living bacteria and microorganisms from milk to increase the shelf life and improve the taste of milk, or the isolation of casein and whey proteins from milk for pHarmaceutical and medical purposes, as well as the production of low-lactose or lactose-free milk for patients with Digestive problems, use membrane processes, especially ultrafiltration and microfiltration, and the main problem in these methods is the fouling of the polymer membranes used, which results in the loss of flux or the reduction of product quality and system efficiency. With the help of bulk modification and surface modification of the... 

Membrane processes are accounted as the newest technology for gas separation and nowadays are more applicable in different petroleum, gas and petrochemical industries because of abundant advantages. One of important application of membrane gas separation technology is syngas adjustment and hydrogen enrichment. In this research, the appropriate alumina nanocomposite membranes for this purpose are prepared and their gas separation performance is investigated. Therefore the mixed matrix membranes, containing the continues polymeric phase polyethersulfone and dispersed phase alumina nanoparticles is synthesized by using methods of experimental design. As the best of our knowledge, there is no... 

Many aroma compounds of fruit juice recovered by thermal processes like evaporation and distillation can lead to undesirable chemical changes and even their loss. Pervaporation is a promising process for the recovery of volatile organic compounds from their aqueous solutions. In the present work, pervaporation recovery of Butyl acetate as a model solution ofgrape juice aroma compoundwas evaluated with polyethersulfone (PES) and ethylvinylacetate (EVA) membranes. PES membrane generally showed better selectivity so that the separation factor at the concentration of 500 ppmand the temperature of 30°C for PES and EVA membranes, respectively, was 230.78 and 156.9. The effect of two operating... 

It is well known that sulfur removal from petroleum is necessary for both industrial and environmental reasons. Sulfur in petroleum products corrodes parts of internal combustion engines and refineries due to the formation of sulfur oxyacids and causes major air pollution and acid rain due to exhaust from diesel engines and emission of sulfur oxides. Hydrodesulfurization (HDS), biodesulfurization (BDS), extraction by ionic-liquids (ILs), selective adsorption, alkylation desulfurization and oxidative desulfurization (ODS) are some methods, can be effective in removal of sulfur compounds. Among these new processes, ODS appears to be particularly promising and is currently receiving increasing... 

Recently separation technology has been developed and engineers are trying to find more rapid and more economic ways in order to reach pure materials. One of the most important needs of human being is natural gas which has some impurities. Acid gases such as carbon dioxide and hydrogen sulfide must be separated from methane. This operation is called gas sweetening. Membrane contactors are equipments recently developed and may be used instead of packed towers for gas sweetening in the future. In this project we designed and made a membrane contacting unit to separate carbon dioxide and hydrogen sulfide from methane. This unit lets you to study the effect of many parameters such as gas and... 

In recent years, bimetallic metal-organic frameworks have attracted the great attention of researchers due to their dual properties and synergistic effects. In this research and inspired by green chemistry, the synthesis of a magnetic nanocomposite of the defective green metal-organic framework was implemented, which carries metallic silver nanoparticles (Ag NPs@Cu-MOF). Then, the sulfonated compounds were synthesized with the prepared nanocomposite because of the importance and widespread medicinal use of sulfur-containing compounds especially sulfonated compounds, and the difficulty of their preparation methods. It is noteworthy to mention that the sulfonation reaction was done by... 

The purpose of this study is to prepare platinum nanoparticles catalysts whitch can be used to C-H activation processes. In order to increase platinum salt catalytic activity, by converting it into a catalyst with characteristics of having recovery cycles, convenient separation and environmental friendliness and being in nano size. Consequently, platinum nano particles were grafted on modified graphene oxides. Catalysts structures were verified by scanning electron microscope, fourier transform infrared spectroscopy, X-ray diffraction, and energy dispersive spectroscopy. Subsequently catalytic activity was examined for C(sp3)-H activation reaction with 3 amines and C-C bond formation. A... 

The forward osmosis (FO) process is a high potential emerging membrane process in the seawater desalination and contaminated water treatment fields. One of the main challenges facing this process is the weak separation (high reverse solute flux, low water flux, and insufficient selectivity) and antifouling performances of its membranes. Various sections of this study focus on the development of FO membranes and their performance improvement. For this purpose, thin-film composite membranes with the same combination of polyethersulfone/polyamide (PES/PA) have been used to investigate the effect of metal-organic frameworks (MOFs) introduction on their performance. The support layer in all cases... 

Although polyacrylamides and theirs modified polymers have an extremely application in the industry mechanical weakness, such as viscosity in salinity or high temperature cause this polymer loss your functional application. In recent years, many endeavors due as modified this polymer by hydrophobics monomers were done but unfortunately don’t have a significant result. Modified acrylamide monomer and hydrophobic mini-emulsion were survey Most used polymers, such as hydrolyzed polyacrylamide, are not able to high levels of salinity and high temperature of the reservoirs. Dr. Ramazani and theirs group use innovational idea of hydrophilic monomers for overcome to this problem. In this project,... 

In this study the azulene-based ligand 2-(2-pyridylazulene) has been prepared by the coupling reaction between 2-bromopyridine and 2-(2_(6methyl azulene)) -4,4,5,5 tetra methyl-1,3,2- dioxaborolane in the presence of Palladium catalyst, [PdCl2(PPh3)2] .This ligand completely characterized by one and two dimentional NMR spectroscopy and its structure determined using X-ray crystallography method. The reaction of this ligand with 0.5 equivalent of Copper (Ⅰ) or Gold (Ⅰ) metal precursors, [Cu(CH3CN)4]PF6 or [Au(SMe2)Cl] gave the mononuclear Copper (Ⅰ) complex, [Cu (2-(2-pyridyl)6-methylazulene)2]PF6, 1 or Gold (Ⅰ) complex, [Au(2-(2-pyridyl)6-methylazulene)2], 2 respectively. Complexes 1 and 2... 

Hydrogen bonding is an important weak interaction encountered in gas, liquid, as well as solid phases. The hydrogen bond plays a very vital role in many life processes and is one of the most frequently used terms in chemistry and biology.
Polyols or polyhydric alcohols are, strictly speaking, simply organic chemicals containing more than two hydroxyl groups. Each hydroxyl is attached to separate carbon atoms of an aliphatic skeleton.They may also contain ester, ether, amide, acrylic, metal, metalloid and other functionalities; along with hydroxyl groups. Polyols are obtained from many plant and animal sources and are synthesized by a variety of methods. Among important properties of... 

We have reported a new and efficient synthesis of a broad spectrum of heterotetracyclic benzoxazocines via unique tandem 1,3-dinucleophilic addition of different bifunctional nucleophiles to quinolinium and isoquinolinium salts. The reaction generally involves the initial addition of nucleophiles to quinolinium salts to form enamine intermediate which can be trapped by intramolecular O/S-alkylation of nucleophiles. This protocol is a very mild and simple method for construction of eight-membered ring in fused heterocycles in a one-step process. We have also developed an efficient asymmetric synthesis of α,β-disubstituted γ-bisalkoxycarbonyl and α, β- disubstituted γ- phosphono sulfonates via... 

ZnO nanopowder has been successfully synthesized by a microwave-assisted solution approach using Zn(CH3CO2)2.2H2O and NaOH. The results obtained from XRD, SEM and TEM show that the mean particle size is 30 nm. SEM and TEM micrographs of ZnO nanopowder also reveal that nanoparticles have spherical shape. A convenient one-pot multi-component reaction of aromatic aldehydes, enolizable ketones or β-keto esters and acetonitrile in the presence of acetyl chloride and 10 mol % ZnO nanoparticles for the synthesis of β-acetamido ketones/esters at room temperature is described. Catalytic activity of ZnO nanopowder for o-acylation of alcohol and phenol has also been investigated. On the other hand,...