The synthesis of Aspirin involves the chemical interaction between salicylic acid and an acetyl anhydride which causes a chemical reaction that converts salicylic hydroxyl group in to an acetyl group. The reaction above shows the reaction that occurs between salicylic acid, phosphoric acid, and acetic anhydride. First, the phosphoric acid attacks the carbon-oxygen (C=O) of the acetic anhydride which makes it positive. This will make acetic anhydride more prone to nucleophilic attacks. The nucleophile in the reaction is salicylic acid and it was form when oxygen on the phenol group attacked the partial positive charge of a carbon from acetic anhydride.
Carboxylic acid would react with alcohol to produce ester and water molecules. The alcohol and carboxylic acid used in the experiment are organic chemicals. Carboxylic acid are very polar carboxyl group and alcohol are very polar hydroxyl group therefore the carboxylic acid and alcohol are very soluble in water. This however only applies to the lower member of the carboxylic acid and alcohol group. This is because the the lower member is a very polar molecule therefore the very polar alcohol/carboxylic acid would react with the very polar water molecules.
Iron(III) solution was added to the salicylic acid to form a organometallic complex. This makes use of the reaction between the phenol functional group in salicylic acid and ferric ions which allows for visibility due to its violet hue(1). The absorbance is directly proportional to the concentration of salicylic acids. This means that the higher the concentration of salicylic acid, the higher the amount of salicylate-iron complex formed, resulting in higher violet intensities and hence a higher absorbance, as seen from table 1. Since the Fe3+ ions react with the singular phenol functional group in salicylic acid, the amount of Fe3+ added should be in a 1:1 ratio with the concentration of salicylic acid.
Chromic acid cleanly oxidizes secondary alcohols to ketones using acetones as solvent and the product isolation is simple. The terpene borneol (with an endo-secondary hydroxyl group, -OH) is oxidized to camphor as below: Oxidation of borneol is an exothermic reaction, in order to avoid creation of side product; the experiment should be carried out at room temperature. Extreme heat will lead to creation of camphoric acid, therefore the heat should be controlled when carrying out the experiment. Result and calculation:
Hydrolysis Rates of Esters Purpose Esters can be hydrolyzed to the corresponding carboxylic acid and alcohol with a decrease in the pH level as the acidic component is formed. The purpose of this experiment is to compare the hydrolysis rates of esters by monitoring the pH values of their aqueous solutions as a function of time. The esters being compared are ethyl acetate, ethyl benzoate, ethyl formate, and ethyl butanoate while the pH level can be determined by the change in color of the solution with the use of sodium hydroxide (NaOH) for the base and the universal pH indicator. The two factors that affect the rates for the hydrolysis of esters is the steric factor and the electronic factor which will serve as the determining factor of how
It is a benzene derivative with three carboxylic acid groups. Trimesic acid is a planar molecule .It is one of the four benzenecarboxylic acids with this property. Trimesic acid can be combined with para-hydroxypyridine to make a water-based gel, which will be stable up to 95 °C. Trimesic acid crystallizes from water in a hydrogen bonded hydrated network with wide
(1977) have developed a method for determination of sodium alkyl sulfonates. The sodium alkyl sulfonates (PS) prepared from paraffin by sulfoxidation reaction are used as effective anionic detergents. The products are mixture of secondary sulfonate isomers. The analysis of each isomer is important for the elucidation of reaction mechanism of sulfoxidation and their physical properties. The authors carried out the isomer analysis of PS by means of Nuclear magnetic resonance spectroscopy (NMR) method with the NMR shift reagent, Eu (dpm).
If the contents in the test tube were not equalised, then the test tube was allowed to rest in the water bath for 5.0 ± 0.6 minutes more. Attached the test tube to the utility clamp, while having the test tube still submerged in the water bath. Used a 10.0 ± 0.1 cm3 graduated cylinder to measure and transfer 10.0 ± 0.1 cm3 of prepared H2O2 solution into the test tube. Instantly, covered the test tube with the rubber tubing that had a one-hole rubber stopper attached to it and ensured that the rubber stopper fitted securely to avoid any leakage of oxygen gas. The set-up of the experiment at this point can be seen in Figure 3.
Nitrogen was used as the carrier gas (0.8 m / min gas flow). The injection temperature was 220 °C splitless mode. The temperature program was 200°C for zero hold min (10°C/ min) until 250°C (5°C/min) and held at this temperature for 9 minute total run time was 9 min. A standard mixture of methyl esters was analyzed under identical condition prior to running the samples. The retention times of the unknown samples of methyl esters were compared with those of
Volatile acids also contribute to fermentative aroma. Acetic acid which has a distinctive vinegar aroma is by far the foremost component of this group, but medium-chain fatty acids can also be found in wine at low concentrations (Bardi et al., 1999). Another group of compounds that add complexity to the wine aroma are higher alcohols which are also referred as fusel alcohols. The exact role of these compounds is unclear. They can be produced either from amino acids via the Ehrlich pathway or in an anabolic manner from sugars; the latter of these paths is more common in wine (Bell and Henschke, 2005).