2-hydroxybenzoic acid, C6H4(OH)COOH - commercially known as salicylic acid exists as a colourless, crystalline organic carboxylic acid. It is partially soluble in water and completely soluble in ethanol and ether. This acid is very commonly used in the preparation of its ester derivatives as it contains both a hydroxyl (-OH) and a carboxylic (-COOH) group. Due to the presence of these functional groups, it is able to react with both an acid and an alcohol.1 (“Salicylic acid”). The very first preparation of salicylic acid was made by Italian chemist Raffaele Piria in 1838 from salicylaldehyde.2 (Brown). The bark and leaves of the willow tree are natural sources of salicylic acid having both analgesic and antipyretic properties. However it is …show more content…
This was first done by Italian chemist, Piria (1839). Salicin hydrolyses in aqueous media to form glucose and salicylic alcohol (saligenin). Salicylic alcohol is then oxidised to form salicylic acid. (Schrör 2010) Another natural source of salicylic acid is methyl salicylate present in wintergreen oil. Salicylic acid is obtained by hydrolysing methyl salicylate, an ester under basic conditions. This synthesis takes place through a 2-step organic reaction. It is also referred to as saponification. Saponification is a special type of hydrolysis which converts an ester into an alcohol and a carboxylic acid. The first step (1) of the hydrolysis, involves the addition of NaOH to methyl salicylate. The reaction is then put under reflux. This produces the sodium salt of salicylic acid known as sodium salicylate. The end products of saponification are alcohol and carboxylic acid. Therefore, in the second step (2), the sodium salicylate collected is then acidified using sulphuric acid to convert the organic salt into the protonated carboxylic acid, salicylic acid. Since the acid is a solid, it be easily isolated from the alcohol produced, methanol, and then purified by crystallisation. The mechanism of
It forms a complex with HBr and extracts it from the aqueous phase into the organic phase where the alkene is. This dehydrates the acid, making it more reactive so that the addition reaction is possible. Rapid stirring is required in order to maximize the surface area
The Identity of the unknown, in this case unknown A, was determined to be acetyl salicylic acid. This was determined by comparing the melting points of the purified unknown crystals to the crude unknown. The known melting point range for acetyl salicylic acid is 135°C -136°C. The Unknown’s melting point was slightly off at 128.6°C - 132°C. This can be due to impurities of the crystals during the purification process.
Explain why the reaction between sodium sulphate and silver nitrate did not occur even though sodium sulphate is insoluble in the most part? The reaction did not occur because the solution was mixed with 0.1M of silver nitrate and 0.1M of silver nitrate is not strong enough for the reaction to occur. If silver nitrate contained more than 0.1 mole, the reaction would have occurred because silver sulphate is insoluble and is a solid. Why is it needed for barium nitrate and ammonium sulphate to dissolve into water separately first before mixing the two together?
There are numerous ways for the synthesis of organic esters and most of which have been briefly studied by Yadav and Mehta 7. The simple and old route for preparing esters is by the reaction
Using filtration sodium acetate was separated, and the filtrate was evaporated to obtain syrup and fractionated at a boiling point of 133-136 °C. The obtained product dissolved in hydrogen bromide of glacial acetic acid and this mixture reaction kept in an ice bath for 1hr. According to procedure, the product was methylated to obtain 1bromo-2, 3, 4, 6-tetramethylglucose.
Results: Table 1: Results from the Salicylic acid (g) and the Purity of ASA (g) Experiment Mass of salicylic acid (g) 0.14 g Mass of filter paper (g) 0.47 g Mass of “impure” ASA + filter paper (g) 0.56 g Mass of prepared “impure” ASA (g)
Aspirin is considered a “polydrug” due to its variety of uses stretching from pain-relief to disease prevention. Salicylic acid is derived from the bark and leaves of the willow tree. Salicylic acid belongs to a group of phytochemicals which have been shown to have positive effects on human health. Salicylic acid is a phenolic compound that can be found in a variety of plants and is a crystal organic carboxylic acid. However, it is more commonly viewed as the primary metabolite and active compound of acetyl salicylic acid, which has been used as an anti-inflammatory drug by physicians for over 100 years.
The fatty acids in these are then made into fatty alcohols then undergo another process to sulfonate them into crystalline salt. Sodium Laureth Sulphate is Sodium Lauryl Sulphate that has been through a process called ethoxylation. Honestly (October 2015). Stacey Rosenberg (02/11/2014) Benzoyl Peroxide
# : Mevacor tablets are preserved by storing them in well-closed, light-resistant containers in a cool place or at controlled room temparature. ZARAGOZIC ACIDS : Zaragozic acids belongs to the family of natural products produced by fungi. The first synthesised zaragozic acids A,B and C were isolated from an unidentified sterile fungal culture,"Sporormeilla intermedia".
It is understood the mechanism is acid-catalyzed where protons coordinate with the carbonyl oxygen to make the carbonyl carbon more electropositive for nucleophilic attack (Scheme 1). In the experimental procedure all reactants were added together, this is inefficient as the protons can coordinate with either trans-cinnamic acid or methanol. Coordination with methanol is unnecessary as it reduces its nucleophilicity and makes less protons available to coordinate with the carboxylic acid. To improve
CLAIRE MUNTING 29/01/2018 Criterion C EFFECTS OF SURFACE AREA OF CALCIUM CARBONATE UPON RATE OF REACTION Calcium Carbonate Chips 1 Introduction: Within the current investigation, the effects of the surface area of Calcium Carbonate (CaCO3) in combination with Hydrochloric acid (HCl) upon its rate of reaction. CaCO3, commonly referred to as limestone, is an organic substance and is, in a sense, the crystallised “carbonic salt” of the element, calcium2. In addition to being a salt, the pH level of Calcium Carbonate is 9.91, and it is therefore, a basic substance, due to the fact that it is comprised of a pH level higher than 7, which is neutral3. HCl, however, is the bodily acid found in the stomach of human beings.
Introduction The goal of the experiment is to examine how the rate of reaction between Hydrochloric acid and Sodium thiosulphate is affected by altering the concentrations. The concentration of Sodium thiosulfate will be altered by adding deionised water and decreasing the amount of Sodium thiosulphate. Once the Sodium thiosulphate has been tested several times. The effect of concentration on the rate of reaction can be examined in this experiment.
Abstract The unknown concentration of benzoic acid used when titrated with standardized 0.1031M NaOH and the solubility was calculated at two different temperatures (20◦C and 30◦C). With the aid of the Van’t Hoff equation, the enthalpy of solution of benzoic acid at those temperatures was determined as 10.82 KJ. This compares well with the value of 10.27KJ found in the literature.
ACID DEPOSITION AND ACID RAIN: Acid deposition is caused by acidic particles and gases that deposit or fall to the Earth. Acid deposition can be wet or dry. Wet deposition is deposition of acidic gases such as oxides of sulfur and nitrogen and acidic particles brought down as precipitation by rain, fog and snow. Dry deposition is dry deposition of acidic gases in the absence of rain or precipitation.
Summary Fish oil is very susceptible to oxidative degradation offering lipid peroxides, secondary and tertiary oxidation products. These products pose health risks, cause fishy odour and taste and reduce shelf-life stability. Microencapsulation techniques such as spray drying and coacervation were used to encapsulate fish oil to resolve these problems. Introduction