Call us toll-free

liquids as solvents for catalysis and organic synthesis has been ..

01/07/2009 · Green Solvents: For Organic Synthesis [V

Approximate price

Pages:

275 Words

$19,50

Green solvents for organic synthesis

N2 - Enzymatic synthesis of ethyl lactate was studied in organic solvents and in ionic liquids to determine optimal media for the reaction, and to investigate the effect of water content on the ester yield. Experiments proved that Cyphos 202 ionic liquid is the best solvent affording the highest ethyl lactate yields. Furthermore, 20 times less enzyme sufficed to carry out the reaction in this ionic liquid compared to organic solvents; ionic liquid could be applied as solvent. Using water removal, the ester yield decreased since a side reaction, dimerization of lactic acid, occurred as well. In contrast to these results, without water removal, the produced water was partly consumed by the decomposition of lactoyllactic acid to free lactic acid, increasing thus the substrate concentration of the mixture and enhancing the ester yield.

Organic synthesis is usually performed in ..

Various commonly used organic solvents were dried with several different drying agents. A glovebox-bound coulometric Karl Fischer apparatus with a two-compartment measuring cell was used to determine the efficiency of the drying process. Recommendations are made relating to optimum drying agents/conditions that can be used to rapidly and reliably generate solvents with low residual water content by means of commonly available materials found in most synthesis laboratories. The practical method provides for safer handling and drying of solvents than methods calling for the use of reactive metals, metal hydrides, or solvent distillation.

NMR Chemical Shifts of Common Laboratory Solvents as …

1 The Applications ofWater as Reagents in Organic Synthesis 1 Zhengkai Chen and Hongjun Ren

Many organic solvents are immiscible with aqueous solutions, but they are able to dissolve significant amounts of water because of their polarity i.e., diethyl ether dissolves 7 % of its weight in water while tetrahydrofuran is completely miscible with water (). Unfortunately, water is a compound that is very difficult to remove from many compounds, because they are either holding on to it well (i.e., alcohols) or the compound itself is steam volatile. Bottom-line is that the more polar the solvent is, the more hygroscopic it will usually be because it dissolves the water better. Thus, removing water and other impurities from a solution can become an arduous task but is necessary if the reagents are also sensitive towards water i.e., Grignard reagents or in cases where water has a detrimental effect on the yield or rate of the reaction. In those cases, drying agents like calcium hydride (CaH2), sodium metal (in combination with benzophenone) or lithium aluminum hydride (LiAlH4) are used to chemically destroy the water in the solvent. Those compounds are relatively reactive and difficult to handle and usually not used in lower division undergraduate laboratories (see below).

Use of Conventional Drying Agents

Commonly used drying agents in organic laboratories are calcium chloride (CaCl2), sodium sulfate (Na2SO4) calcium sulfate (CaSO4, also known as ) and magnesium sulfate (MgSO4), all in their anhydrous form. All four of them readily form hydrates at low temperatures according to

Enzymatic synthesis of ethyl lactate was studied in organic solvents and in ionic liquids to determine optimal media for the reaction, and to investigate the effect of water content on the ester yield. Experiments proved that Cyphos 202 ionic liquid is the best solvent affording the highest ethyl lactate yields. Furthermore, 20 times less enzyme sufficed to carry out the reaction in this ionic liquid compared to organic solvents; ionic liquid could be applied as solvent. Using water removal, the ester yield decreased since a side reaction, dimerization of lactic acid, occurred as well. In contrast to these results, without water removal, the produced water was partly consumed by the decomposition of lactoyllactic acid to free lactic acid, increasing thus the substrate concentration of the mixture and enhancing the ester yield.

Organic Synthesis in Water - Organic Chemistry Portal

substitution of volatile organic solvents in solution phase synthesis.

AB - Enzymatic synthesis of ethyl lactate was studied in organic solvents and in ionic liquids to determine optimal media for the reaction, and to investigate the effect of water content on the ester yield. Experiments proved that Cyphos 202 ionic liquid is the best solvent affording the highest ethyl lactate yields. Furthermore, 20 times less enzyme sufficed to carry out the reaction in this ionic liquid compared to organic solvents; ionic liquid could be applied as solvent. Using water removal, the ester yield decreased since a side reaction, dimerization of lactic acid, occurred as well. In contrast to these results, without water removal, the produced water was partly consumed by the decomposition of lactoyllactic acid to free lactic acid, increasing thus the substrate concentration of the mixture and enhancing the ester yield.

Enzymatic esterification in organic media: role of water and organic solvent in kinetics and yield of butyl butyrate synthesis

Order now
  • Perfume (Esters) - Academic Technology - iTech Server

    (2005), The Role of Precursor-Decomposition Kinetics in Silicon-Nanowire Synthesis in Organic Solvents

  • AQA | Chemistry | Subject content | Organic chemistry

    Various commonly used organic solvents were dried with several different drying agents

  • Beyond Benign | Green Chemistry Education

    Microwave Synthesis

Order now
  • Kim

    "I have always been impressed by the quick turnaround and your thoroughness. Easily the most professional essay writing service on the web."

  • Paul

    "Your assistance and the first class service is much appreciated. My essay reads so well and without your help I'm sure I would have been marked down again on grammar and syntax."

  • Ellen

    "Thanks again for your excellent work with my assignments. No doubts you're true experts at what you do and very approachable."

  • Joyce

    "Very professional, cheap and friendly service. Thanks for writing two important essays for me, I wouldn't have written it myself because of the tight deadline."

  • Albert

    "Thanks for your cautious eye, attention to detail and overall superb service. Thanks to you, now I am confident that I can submit my term paper on time."

  • Mary

    "Thank you for the GREAT work you have done. Just wanted to tell that I'm very happy with my essay and will get back with more assignments soon."

Ready to tackle your homework?

Place an order