Introduction: Aldol Condensation‚ a useful carbon-carbon bond-forming is the an example of a reaction named based on the type of product formed. This product formed involves two aldehydes or ketones in the presence of dilute base‚ yields a molecule having both aldehyde and alcohol. The aldol products are β-hydroxyaldehydes or β- hydroxyketones. Condensation reaction is the transformation that result from combination of large molecules to produce another larger molecule. In an aldol condensation‚ β-hydroxyaldehyde
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Aldol Condensation Discussion: 1. Aldol condensation reactions take place in basic conditions‚ where a deprotonated enol becomes an enolate and proceeds to attack the aldehyde. Since the solution is basic‚ it is able to deprotonate the alpha carbons of the product‚ which forces the hydroxide groups to leave. The product is then considered to be dehydrated and unsaturated. In terms of our reaction‚ cyclopentatone is deprotonated to form an enolate‚ which then attacks the two molecules of p-tolualdehyde
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Experiment 11: Synthesis of Dibenzalacetone by the Aldol condensation Introduction: The Aldol condensation reaction‚ under basic conditions‚ involves the nucleophilic addition of an enolate ion to another carbonyl group. The resulting product‚ a beta-hydroxy ketone or aldehyde‚ is called an aldol because it contains both and aldehyde group and the hydroxy group of alcohol. Condensations‚ including aldol condensation‚ combine two or more molecules‚ typically with a loss of a smaller molecule (including
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Objective: The benefit of this lab was to acquaint oneself with the fundamentals of the Aldol Condensation reaction by demonstrating the synthesis of dibenzalacetone (trans‚ trans-1‚5-Diphenyl-1‚4-pentadien-3-one) through the aldol condensation of acetone with benzaldehyde. The synthesis began by using a strong base to generate the acetone enolate ion. The ketone/enol tautomerization is an equilibrium process that produces little of the enol (ppm or less). However‚ any enol that formed quickly reacted
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Preparation of Dibenzalacetone by the Aldol condensation David o Neill Date of experiment: 14/12/2011 Apparatus Steam bath‚ ice bath‚ Buchner funnel‚ beaker‚ conical flask‚ filter paper‚ TLC apparatus‚ Melting point apparatus Materials / chemicals Benzaldehyde‚ acetone‚ ethanolic sodium hydroxide‚ ethanol Introduction The synthesis of dibenzalacetone is formed from an Aldol condensation reaction. An Aldol condensation reaction is a very effective way of forming a carbon – carbon bond reaction‚ in
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Thiamine-Catalyzed Benzoin Condensation I.Conclusion Benzoin was produced by reacting 2 mols of benzaldehyde with the catalyst thiamine to form a new C-C bond. A total of 2.626 grams were recovered. There was a 33% recovery of benzoin. The low percent recovery could be due to the purity of the limiting reactant‚ benzaldehyde. Upon filtration‚ the mother liquid appeared oily making it more likely that the low recovery was due to the solution ‘oiling out.’ This could be avoided in the future
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Introduction: The purpose of this experiment is to use sodium borohydride to reduce benzil. However‚ stereochemistry allows for five possible products. If only one carbonyl group is reduced during the reaction a racemic mixture of benzoin will be the product that is produced. After the first reduction a chiral center forms causing the second reduction to occur from only one side of the ketone. Depending on which side the second reduction take place there are three possible products including: a racemic
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BOILING AND CONDENSATION BOILING • Phase change phenomenon where in transformation of liquid to vapour occurs at the saturation temperature of the fluid. It occurs at a solid/liquid interface due to convection heat transfer from the solid and usually occurs at surface temperatures higher than the saturation temperature of the fluid Agitation of fluid by vapor bubbles provides large convection coefficients Modified Newton’s law of cooling qs’’ h Ts Tsat Te • • • BOILING – CLASSIFICATON
Free Heat transfer Heat
the final product‚ tetraphenylcyclopentadienone. The first step of the experiment was the condensation of benzaldehyde to yield benzoin. Thiamine catalyst along with water and ethanol were added to the benzaldehyde‚ then NaOH was added until the solution turned yellow. After recrystallization‚ the product was benzoin. Step two was the oxidation of benzoin to benzil. Nitric acid was added to the benzoin and heated‚ this was followed by recrystallization to yield the benzil. In step three the
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54.4% 15.765 g Melting Point of Intermediate (Benzoin) Melting Point of Product (Benzil) Trial 1 – 129-131°C Trial 2 – 133-135°C Trial 3 – 132-135°C Trial 1 – 92-93°C Trial 2 – 92-94°C Trial 3 – 93-95°C Average Melting Point Observed (Intermediate): 131.3-133.6°C Average Melting Point Observed (Product): 92.3-94°C Theoretical Melting Point of Benzoin: 132°C Theoretical Melting Point of Benzil: 94.5°C Discussion and Conclusions:
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