نتایج جستجو برای: reaction yield
تعداد نتایج: 593730 فیلتر نتایج به سال:
The rheological properties of acid hydrolyzed corn stover at high solids concentration (20-35 wt.%) were investigated using torque rheometry. These materials are yield stress fluids whose rheological properties can be well represented by the Bingham model. Yield stresses increase with increasing solids concentration and decrease with increasing hydrolysis reaction temperature, acid concentratio...
Esterification of acetic acid with methanol with and without heterogeneous catalyst was carried out in compressed carbon dioxide. In the first part of this project the autocatalytic effect of the compressed CO2 on this equilibrium reaction was investigated. The use of high-pressure carbon dioxide, an environmentally benign solvent, will shift the yield towards the desired product methyl acetate...
The polymerase chain reaction (PCR) has found wide application in biochemistry and molecular biology such as gene expression studies, mutation detection, forensic analysis and pathogen detection. Increasingly quantitative real time PCR is used to assess copy numbers from overall yield. In this study the yield is analyzed as a function of several processes: (1) thermal damage of the template and...
silica gel has been used for synthesis of biscoumarin derivatives starting from 4-hydroxycoumarin and aryl aldehydes. the reaction conditions are completely in agreement with green chemistry principles including sing water as media and a recyclable and safe catalyst. this method is also simple and inexpensive and leads to high yield of products in short reaction times.
Efficient selective synthesis of the secondary amide surfactant N-methyl lauroylethanolamide from methyl laurate and N-methylethanol amine by carrier-fixed Chirazyme L-2 (Candida antarctica) using a kinetic strategy has been demonstrated. When different solvents were screened for product yields using Chirazyme L-2, acetonitrile was found to be optimal. The rate of the reaction increased sharply...
The title compound [(?75-rBu3Cp)CoBr]2 1 is prepared in a one pot reaction starting from 1,2,4fBu3-cyclopentadiene followed by metallation and by reaction of the resulting ?Bu3Cp“K+ anion salt with anhydrous CoBr2 in THF. 1 was isolated from this reaction in 78% yield as black crystals. 1 reacts with LiAlH4 in THF at 0 °C. Subsequent alcoholysis of the crude reaction mixture with ethanol at -78...
reaction of aryl methyl ketone with isatin in the presence of a base afforded 2- arylquinoline-4-carboxylic acid (3). reaction of diazomethane with compound 3 yielded the ester 4. compound 5 was prepared from the reaction of n, n'-dialkylethyl (or propyl) arnine with 4. addition of hydrazine hydrate to compound 4a gave 2- (2- pyridyl) quinoline-4-carboxylic acid hydrazide (6). reaction of ...
N-Propylsulfamic acid supported onto magnetic Fe3O4 nanoparticles (MNPs-PSA) was investigated as an efficient and magnetically recoverable catalyst for the one-pot synthesis of substituted coumarins from the reaction of coumarin with variety aromatic aldehydes in high to excellent yield at room temperature under solvent-free conditions. The magnetic nanocatalyst can be readily recovered easily ...
A powerful and convenient reaction procedure for the C-N coupling reaction (the Buchwald-Hartwig reaction), yielding products of N-arylanilines and N-arylamines in both conventional heating and microwave irradiation has been reported. The protocol utilizes a stable and new supper ferromagnetic nanoparticle chelating N-heterocyclic dicarbene palladium(II) complex (Pd-NHC) as catalyst which helps...
Present work describes the synthesis of coumarin Mannich bases 4-7 by the application of Mannich reaction on 7-hydroxy-4-methyl coumarin 3 using conventional as well as microwave technology to compare the feasibility, reaction time and yield of the product. For this, 7-hydroxy-4-methyl coumarin 3 was prepared using Pechmann condensation reaction and Mannich bases (4-7) were synthesized by the r...
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