Esters are defined as molecules consisting of a carbonyl group which is adjacent to an ether linkage. They are polar molecules which are less polar than alcohols but more so than ethers, due to their degree of hydrogen bonding ability. Most often derived from reacting an alcohol with a carboxylic acid, esters are a unique, ubiquitous class of compounds with many useful applications in both natural and industrial processes 1. For example, within mammals, esters are used in triglycerides and other lipids as they are the main functional group attacking fatty acids to the glycerol chain 2. A unique property of esters is their tendency to give off distinct aromas such as the scent of apples (Ethyl caprylate) and bananas (Isoamyl acetate). This is of a unique importance especially in industries that utilize flavors and aromas such as the tobacco, candy and alcohol industry. Consistent research is conducted in order to enhance and increase the effectiveness of esters in these products 3. The most classic and standard procedure for producing esters is the Fisher-esterification reaction. Discovered in 1895 by German chemists Emil Fischer and Arthur Speier 4, this reaction involves refluxing a carboxylic acid and an alcohol in the presence of an acid catalyst. In order to drive the equilibrium towards the products, the water from the dehydration process must be removed and there must be an excess amount of alcohol. A vast range of carboxylic acids may be used for this reaction however the type of alcohols are limited. Primary and secondary alcohols are most frequently used in esterification reactions, tertiary alcohols are steric ally hindered usually resulting in poor yields5 and tend to undergo elimination reactions instead. In this rea... ... middle of paper ... ...Wiley & Sons: 2008; pp 115-119 Neises, B.; Steglich, W. Simple Method for the Esterification of Carboxylic Acids. Angewandte Chemie International Edition in English. 1978,17,7, 522-524. Mitsunobu, O.; Yamada, M. Preparation of Esters of Carboxylic and Phosphoric Acids via Quaternary Phosphonium Salts. Bulletin of the Chemical Society of Japan. 1967,40,10, 2380-2382. Obrecht, D. Medicinal Chemistry: Combinatorial Chemistry-Parallel Synthesis. Polyphor Ltd. 2009, 26-51 Dydio, P.; Breuil, P.R.; Reek, J.H. Dynamic Combinatorial Chemistry in Chemical Catalysis. Israel J ournal of Chemistry, 2013, 53, 2, 61-74 APPENDIX Sample Calculation: Percent yield: The theoretical mass of ethyl salicylate to be obtained was 1.667 grams and the actual mass obtained was 0.600 g. Percent Yield=(Experimental Yield)/(Theoretical Yield)*100 =0.600g/1.667g*100 = 36.1%
barbier reaction: In a 50 mL round bottom flask that had a reflux condenser attachment, saturated ammonium chloride (5 mL), THF (1 mL), zinc powder (0.4 g), benzaldehyde (0.500 mL, 0.5225 g, 4.92 mmol), and allyl bromide (0.470 mL, 0.6533 g, 5.40 mmol) were charged with stir bar and stirred at room temperature for 45 minutes. Diethyl ether (10 mL) was added to the reaction mixture and stirred. The mixture was gravity filtered into a beaker that was topped with a watchglass. The filtrate was transferred to a separatory funnel and the organic layer was extracted with deionized water (10 mL) and diethyl ether (15 mL). The organic layer was placed into an Erlenmeyer flask and the aqueous layer was placed into a beaker, which was extracted with
The experimental Fischer esterification of 8.92g of acetic acid with 5.0g of isopentyl alcohol using concentrated sulfuric acid as a catalyst yielded 4.83g (65.3% yield) of isopentyl acetate. The product being isopentyl acetate was confirmed when the boiling point during distillation had similar characteristics to that of the literature boiling points2. Physical characteristics like color and smell also concluded a match of our product with what was intended. 1H-NMR spectroscopy analysis supported this claim due to the fact that the integration values and chemical shifts were comparable to isopentyl acetate. Lastly, infrared spectroscopy (IR) showed similar key characteristics of our product’s wavelengths to that of pure isopentyl acetate5.
Hydration of alkenes is characterized by the addition of water and an acid-catalyst to a carbon-carbon bond leading to an alcohol. Dehydration is exactly the opposite in which dehydration of an alcohol requires water to be removed from the reactant. Equilibrium is established between the two processes when the rate of the forward reaction equals the rate of the reverse reaction. The alkene that is used in this experiment is norbornene. Through hydration of norbornene, an alcohol group should be present on the final product yielded what is known as exo-norborneol. Percent yield is a numerical indication of how much of the reactant was actually reacted to yield product. The equation for percent yield is shown below:
Biological waxes are esters of long-chain (C14 to C36) saturated and unsaturated fatty acids with long-chain (C16 to C30) alcohols. Their melting points (60 to 100 _C) are generally higher than those of triacylglycerols.In plankton, the free-floating microorganism sat the bottom of the food chain for marine animals, and waxes are the chief storage form of metabolic fuel. Waxes also serve a diversity of other functions related to their water-repellent properties and their firm consistency. Certain skin glands of vertebrates secrete waxes to protect hair and skin and keep it pliable, lubricated, and waterproof. Birds, particularly waterfowl, secrete waxes from their preen glands to keep their feathers water-repellent. The shiny leaves of holly, rhododendrons, poison ivy, and many tropical plants are coated with a thick layer of waxes, which prevents excessive evaporation of water and protects against parasites. Biological waxes find a variety of applications in the pharmaceutical, cosmetic, and other industries. Lanolin (from lamb’s wool), beeswax carnauba wax (from a Brazilian palm tree), and wax extracted from spermaceti oil (from whales ;)
This report address the process in which Yeast fermentation occurs best depending on the type of sugar used as a food source for yeast in order to ferment and create ethanol. In this experiment our group tested two different sugars, sucrose and stevia, The reason for testing Sucrose is due to the fact that it contains glucose and fructose in its molecular structure and in order for fermentation to occur glucose must be present in the production of ethanol and as a food source of yeast (Sugar). Stevia was chosen because of its complex structure and having no resemblance to glucose. Stevia is considered an artificial sweetener and its molecular orientation of atoms makes its shape longer as compared to glucose which is a bulky molecule. In addition,
Many derivatives and oleochemicals of castor oil require relatively simple methods for their production, while higher generation derivatives such as sebacic acid or salts of ricinoleic and undecylenic acid could require more sophisticated production methods.
The purpose of conducting this experiment was to synthesise and characterise for the preparation of benzocaine via a fishcer esterification reaction by the means of amino benzoic acid alongside ethanol. The product was also precipitated from a solution in order to gain a pH of 8.The secondary aim was to esterify the reaction in an equilibrium reaction catalysed via the addition of acid shown below:
The competing enantioselective conversion method uses each enantiomer of a kinetic resolution reagent, in this case R-HBTM and S-HBTM, in separate and parallel reactions, where the stereochemistry of the secondary alcohol is determined by the rate of the reactions. When using the CEC method, the enantiomer of the secondary alcohol will react with one enantiomer of the HBTM acyl-transfer catalyst faster than with the other HBTM enantiomer. The mnemonic that identifies the absolute configuration of the secondary alcohol is as follows: if the reaction is faster with the S-HBTM, then the secondary alcohol has the R-configuration. In contrast, if the reaction is faster with the R-HBTM, then the secondary alcohol has the S-configuration. Thin layer chromatography will be used to discover which enantiomer of HBTM reacts faster with the unknown secondary alcohol. The fast reaction corresponds to a higher Rf spot (the ester) with a greater density and a slower reaction corresponds to a lower Rf spot with high de...
The goal of this experiment is to determine which products are formed from elimination reactions that occur in the dehydration of an alcohol under acidic and basic conditions. The process utilized is the acid-catalyzed dehydration of a secondary and primary alcohol, 1-butanol and 2-butanol, and the base-induced dehydrobromination of a secondary and primary bromide, 1-bromobutane and 2-bromobutane. The different products formed form each of these reactions will be analyzed using gas chromatography, which helps understand stereochemistry and regioselectivity of each product formed.
The product was recrystallized to purify it and the unknown filtrate and nucleophile was determined by taking the melting points and performing TLC. Nucleophilic substitution reactions have a nucleophile (electron pair donor) and an sp3 electrophile (electron pair acceptor) with an attached leaving group. This experiment was a Williamson ether synthesis usually SN2, with an alkoxide and an alkyl halide. Conditions are favored with a strong nucleophile, good leaving group, and a polar aprotic solvent.
Performing this experiment, we used the technique called Acid-Base extraction to isolate Eugenol, which is one of the main ingredients of clove oil. Acid-Base extraction is the most efficient method for isolating organic component; it is efficient because it purifies the acid and base mixture based on their chemical identities. We have seen throughout this experiment that acid and base play an important role, when it comes to solubility in water. Our basic knowledge of acid and base is acid is a proton donor and base is a proton acceptor. This ideology helps us to understand why organic compounds are not soluble in water. When compounds tend to be insoluble, we have to use acid and base reaction, to change its solubility. The changes that occurred
After the some time, we filter it through a Büchner funnel before it is recrystallized and filtered again. The mass was recorded as it was dry. By adding sodium carbonate, we will now test whether what obtained is benzoic acid or not, because one can observe bobbles if it is an acid. After that we burn it to test if it is aromatic.
Flavor is based on a combination of factors. These factors include taste, smell, texture, and temperature. The following experiment’s main focus is the flavor of food based on the combination of smell and taste. Have you ever pinched your nose while eating and noticed that you can’t taste your food? In this report you will learn how the nose and tongue work together to create flavor. Your sense of smell and sense of taste are very important when deciding the flavor of food.The tongue and nose influence each other more than you may think.
Emulsions are important in food science. Not only do they provide an important sensory aspect in many foods, but a functional one as well. From hollandaise to ice cream, getting hydrophobic and hydrophilic molecules to play nice with each other can be a difficult task. According to Modern Cuisine, it was previously thought that Hollandaise, a classic French emulsion of egg and butter, could only be made by letting butter drip from natural heat of the hand. Of course, modern science has taught us that, with the use of emulsifiers, these mystic mixtures can be created without the voodoo and magic once thought necessary. This paper will discuss emulsions as applied to hollandaise, chocolate, hot dogs and their characteristic pH, moisture content, shelf stability and quality of viscosity. An explanation of the chemical processes that occur between the raw ingredients of each food and the relationship between the structure and function of their components will be explained, as well as the importance of the chemical changes that take place during production. The characteristics that define these foods as emulsions will be compared and contrasted to further elucidate the mystery of the emulsion. Bon Appetite!
In this experiment, lipids from ground nutmeg are extracted using a combination of solvents and identify the lipids through chromatography. The purpose of using solvent combinations is to elute the lipids based on their polarity to binding of the silica gel. The chromatography is performed on a silica gel plate and the use of iodine to visualize the lipids. By calculating the Rf values for each compound and comparing them to the known lipids, we are able to distinguish the lipids within the grounded nutmeg.