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%
Step 6: The ethyl ester on (20) is hydrolysed using concentrated sulphuric acid in a refluxing 1:1 acetic acid/water mixture.
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.
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 ;)
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...
Vrhovsek, U., Rigo, A., Tonon, D., & Mattivi, F. (2004). Quantitation of Polyphenols in Different Apple Varieties. Agricultural and Food Chemistry, 52, 6532-6538.
Esters are produced when carboxylic acids are boiled with alcohols with a catalyst which is usually sulphuric acid. A reaction to make esters is reversible and slow and the reactions are often characterised by the smell formed which is usually a sweet and ‘fruity’ aroma.
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:
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.
Remove the extra solvent on a steam bath under a hood while flushing the flask with N2 gas, leaving the crude extract. Weigh extract.
Before 1850, American’s food flavoring was formerly used as flavored food and beverages from local and foreign sources of flavorings such as rum, fruit juice, and spices in the home. People discovered nature aroma when they found food flavoring could be enriched by simple methods. In the early 20th century, Germany’s chemist discovered one of the first artificial flavors by accident. They created methyl anthranilate as artificial grape flavor while mixing chemicals. Now methyl anthranilate is the main ingredient for grape Kool-Aid. Food flavoring in America began during the industrial revolution. According to Schlosser's “Fast Food Nation,” synthetic flavor additives were used mainly in baked goods, candies, and sodas until the 1950s, when sales of processed food skyrocketed. The invention of machines increased the number of flavors that could be created from chemical synthesis. By the 1960s, the American flavor industry was creating flavors to provide the taste for thousands of new foods (Why the Fries Taste Good).
Sour candies make up a large portion of the candy industry, and using new methods and innovations can help improve the quality of these candies. If the use of oxalic acid and carefully constructed candy wrappers are incorporated in the creation of sour candies, the sourness and quality of these candies will increase as they both influence how humans taste and feel the sour sensation. This is important because finding the answer will not only increase the quality of sour candies around the world, but also revolutionize the world of
Since glycerol has three –OH (alcohol) functional groups, three fatty acids are needed to make three ester functional groups and form tri-ester of glycerol or triglyceride. In addition, water is eliminated in this process.
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.
This, H. (2006). Molecular Gastronomy: Exploring the science of flavour. Columbia University Press, New York, NY.
Tannins, a natural compound produced by many plants, have become a common topic when discussing various beverages and fruits, yet the truth is that tannins are compounds that can be found in most all plants and have a much more involved significance than astringent taste. Tannins are a type of plant product that is classified as a polyphenol (Cornell University 2014). Polyphenols, also referred to as phenolic compounds, can have a high molecular weight due to the attachment of one or many hydroxyl groups to an aromatic ring structure (Balasundram 2006). Phenolic compounds can commonly be found connected to single and complex sugars within plants (Balasundram 2006). There is a vast diversity within the plant polyphenols as related to composition, yet polyphenols are categorized into 12 different classes based on structure (Balasundram 2006). Tannins along with