نتایج جستجو برای: solvent 5 solvent and the third factor
تعداد نتایج: 21395426 فیلتر نتایج به سال:
The efficiency of HZSM-5 Zeolite, tungestophosphoric acid (H3PW12O40) and tungestosililic acid (H4O40SiW12) were investigated in three-component, one-pot synthesis of coumarin dyes. These green and noncorrosive acids were highly efficient in synthesis of some coumarin dyes in excellent yield during concurrent formation of coumarin and benzimidazole or benzoxazole heterocycles (e.g. C. I. disper...
1,3-Butadiene, BD is produced from C4-cut by extractive distillation. The separation of 1,3-Butadiene from C4-cut is not possible through the conventional distillation processes, because several mixtures have consisted of close boiling points constituents and make azeotrope. The BASF extraction distillation process in BD unit of Jam and Amirkabir Petrochemical Company improves the relative vola...
the main purpose of this study was to investigate any relationship between high school efl teachers metaphorical understandings of their role in class and their self-efficacy beliefs. teachers metaphors were elicited through two different prompts: one picturing what they believed a language teacher should be like in class, and the other demonstrating what they are actually like in class; such...
objective(s): it has been suggested that the efficiency of dry poder inhaler (dpi) is generally low. therefore, the aim of the present research work was to use the solvent treatment of the carrier in dpiformulations to see the possibility of inducing desirable characteristics. materials and methods: lactose sieve fractions of 63-90 μm were submerged in ethanol or 80% v/v ethanol, methanol or ...
a pressurized fluid extraction (pfe) method for the extraction of pistachio oil was developed using a modified supercritical fluid extractor. the supercritical fluid extraction apparatus was modified to be able to pump liquid solvent and co2 into the extraction vessel alternatively. the experimental results showed that the extraction yield was independent of the extraction pressure. it was also...
objective: the objective of this study was to investigate the invitro fluoride release of four new self-adhesive resin cements; set (sdi, australia), breeze (pentron, usa), embrace wetbond (pulpdent, usa), g-cem (gc, japan) and to assess the bonding performance of these self-adhesive resin cements for bonding of orthodontic brackets. materials and methods: for fluoride release experiment, six ...
a simple and rapid microextraction procedure based on dispersive liquid-liquid microextraction (dllme) was developed for determination and speciation of trace amounts of chromium (cr) by flame atomic absorption spectrometry (faas). in the proposed approach, chloroform and methanol were used as extraction and dispersive solvents. a new schiff's base ligand, bis(2-methoxy benzaldehyde) ethylene d...
cobalt hydrogensulfate is an efficient catalyst for the condensation of β-naphthol, aromatic aldehydes and 5,5-dimethyl-1,3-cyclohexanedione at 120 °c to afford 9,9-dimethyl-12-phenyl-8,10,11,12-tetrahydro-9-h-benzo[a]xanthen-11-one derivatives in high yields. also, polycondensation reactions of phenols with phthalic anhydride were carried out in the presence of cobalt hydrogensulphate under so...
the formation constants of the species formed in the systems h+ + mo(vi) + histidine and h+ +histidine have been determined at different aqueous solutions of methanol (0 - 45 % v/v) at 25 °c andconstant ionic strength (0.1 mol dm-3 sodium perchlorate), using a combination of spectrophotometricand potentiometric techniques. the composition of the complex species was determined by thecontinuous v...
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