نتایج جستجو برای: esterification reaction
تعداد نتایج: 415713 فیلتر نتایج به سال:
Triphenylphosphine oxide (TPPO) and oxalyl chloride ((COCl)2) are used as novel and high-efficiency coupling reagents for the esterification of alcohols with carboxylic acids via the TPPO/(COCl)2 system at room temperature for 1 h. The reaction represents the first TPPO-promoted esterification under mild and neutral conditions with excellent yields. Furthermore, we proposed a plausible mechanis...
In this work, preparation and crystallization of yttrium iron garnet Y3Fe5O12 super-paramagnetic nanoparticle by aqueous sol–gel processes and its application as an effective nano catalyst for esterification and etherification reactions in short reaction time and in high isolated yields. Then this catalist was used for the synthesis of Dihydropyrimidin derivatives is described. The catalyst was...
Inter-esterification is one of the processes used to modify the physico-chemical characteristics of oils and fats. Inter-esterification is an acyl-rearrangement reaction on the glycerol molecule. On the other hand, hydrogenation involves addition of hydrogen to the double bonds of unsaturated fatty acids. Due to health implications of trans fatty acids, which are formed during hydrogenation, th...
In the current research work, effect of microwave irradiation energy on the esterification of palm fatty acid distillate (PFAD) to produce PFAD methyl ester / biodiesel was intensively appraised. The PFAD is a by-product from refinery of crude palm oil consisting >85% of free fatty acid (FFA). The esterification reaction process with acid catalyst is needed to convert the FFA into fatty acid me...
By DFT calculation, we found that acid-catalyzed carboxylic acid esterification and ester hydrolysis are brief two-step reactions. First, the carboxylic acid hydroxyl-oxygen or ester alkyl-oxygen is protonated, which generates a highly active acylium ion. The protonation requires an activation energy (Ea) of 4-10 kcal mol(-1), and is the rate-controlling step of the esterification or hydrolysis...
An efficient Knoevenegel reaction, addition of Michael, trans-esterification for the synthesis of new polyanionic acyclonucleosids using natural phosphate as catalyst
The alkoxytriphenylphosphonium ion intermediate of the Mitsunobu reaction can be generated using the Hendrickson reagent, triphenylphosphonium anhydride trifluoromethanesulfonate, 1. Strangely, while the reagent 1 can be used in place of the Mitsunobu reagents (triphenylphosphine and a dialkylazodicarboxylate) for the esterification of primary alcohols, secondary alcohols such as menthol underg...
Methyl acetate is produced through catalytic esterification of acetic acid with methanol. Catalytic acceleration is induced by sulfuric acid or ion exchange resins respectively. Acceptable product yield is obtained by reactive distillation. Separation and isolation of methyl acetate has to overcome two azeotropes (methyl acetate – water and methyl acetate methanol). Scope of this project has be...
Energy obtained from renewable sources has increased its participation in the energy matrix worldwide, and it is expected to maintain this tendency. Both in large and small scales, there have been numerous developments and research with the aim of generating fuels and energy using different raw materials such as alternative crops, algae and waste cooking oil. Capparis spinosa seed (containing 3...
−− The synthesis of ethyl hexadecanoate was carried out by esterification of palmitic acid with ethanol in a solvent-free system. A commercial immobilized lipase (Lipozyme RM-IM) was mixed with the reagents, in a 15 mL closed batch reactor with constant stirring and coupled with a condenser. The effects of palmitic acid/ethanol molar ratio (0.16 to 1.84), reaction temperature (65 to 75C) and en...
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