Synthesis of Aspirin Essays

Synthesis of Aspirin Essays Synthesis of Aspirin Essay Synthesis of Aspirin Essay Essay Topic: Synthesis Sypnopsis In this experiment, acetylsalicylic acid was synthesized from the acidification of salicylic acid and acetic anhydride. The objective was to convert a specific amount of salicylic acid into the same amount of aspirin that was high in purity. Furthermore, the other objectives were to enable students to conduct the synthesis of aspirin, reinforce skills or recrystallisation and the technique of melting point determination. The amount of each compound should be the same because there is a 1:1 ratio between them. The purity of the synthesized aspirin was measured by determining its melting point and percent yield. Soluble impurities increase the range over which a compound melts and often decreases its overall melting point temperature1. If the experiment went as expected, a pure sample of aspirin with a high percent yield would have been obtained. The percent yield obtained was 56. 1% and the melting point was 134. 7- 136. 8. Introduction Aspirin (acetylsalicylic acid) is a versatile drug that is consumed in huge quantities worldwide. It is a non-steroidal anti-inflammatory drug (NSAID) with a wide range of physiological effects. The first discovery of aspirin occurred in England, in 1963, believing that the bark of willow trees with a beneficial effect in alleviating distress due to fevers, aches, and pains2. Salicylic acid was later extracted from the willow bark and it proved to be an active ingredient. Salicylic acid was synthesized from basic starting materials by 1860 which was helpful to the medicinal field but there were some problems2. Salicylic acid turned out to be irritating to the membranes of the throat, mouth, and stomach. The product had a high acidity of the compound but fortunately, successful amendments were done, namely, the replacement of the acidic phenolic hydrogen atom with an acetyl group. In 1893, a effective synthesis of acetylsalicylic acid was created, patented in 1899, commercialized under the trade name of ‘aspirin’ by the Bayer Company in Germany3. The name ‘aspirin’ was invented by the chemist, Felix Hoffman, who originally synthesized acetylsalicylic acid for Bayer3. At very low doses, aspirin is used to treat and prevent heart attacks and blood clots. At higher doses, it is used as an analgesic to reduce pain and as an antipyretic to reduce fever. At very high doses, it is an effective anti-inflammatory agent used to treat rheumatic fever, gout and rheumatoid arthritis. It is also an anticoagulant, it dissolves corns and calluses, and it provokes loss of uric acid (a toxin) but promotes retention of fluids in the kidneys. It kills bacteria and induces peptic ulcers. When ingested, acetylsalicylic acid remains intact in the acidic stomach, but in the basic medium of the upper intestinal tract, it hydrolyzes forming the salicylate and acetate ions. When ingested, acetylsalicylic acid remains intact in the acidic stomach, but in the basic medium of the upper intestinal tract, it hydrolyzes forming the salicylate and acetate ions. The exact mechanisms of its pharmacological actions are still under study. In many plants, salicylate can induce flowering. However, aspirin may cause side effects for example, nausea, vomiting, stomach pain and heartburn. Theory Aspirin is prepared from salicylic acid and acetic anhydride with the help of an acid catalyst. Concentrated sulphuric acid acts as a catalyst. After preparation, the product is purified. This is especially important for chemicals that are used as food additives and pharmaceuticals. The most common method of purifying solid organic compounds is by recrystallization. When an impure solid compound is dissolved in a solvent, it is then allowed to slowly crystallize out as the solution cools. As the compound crystallizes from the solution, the molecules of the other compounds dissolved in solution are excluded from the growing crystal lattice, giving a pure solid. Crystallization of a solid is different from a precipitation of a solid. In crystallization, there is a slow, selective formation of the crystal framework resulting in a pure compound. In precipitation, there is a rapid formation of a solid from a solution that usually produces an formless solid containing many trapped impurities within the solids crystal framework. For this reason, experimental procedures that produce a solid product by precipitation always include a final recrystallization step to give the pure compound. Figure: The esterification of salicylic acid by acetic anhydride5. The -OH group of salicylic acid that reacts with acetic anhydride to form an ester-like product. The carboxylic acid group of salicylic acid remains unchanged. Acetic anhydride is used because it is cheap and forms a by-product, acetic acid. Acetic acid is non corrosive and can be recovered to produce more acetic anhydride. Procedure 2. 4g of salicylic acid was weighed and poured into a 100ml conical flask. The actual weight was then recorded. In the fume hood, 6ml of acetic anhydride was added to the salicylic acid in the flask. To this mixture, 3 to 4 drops of sulphuric acid was added, swirled to mix and then heated in a water bath for 10-15 minutes to complete the reaction. The mixture was removed from the water bath while it was still hot and then 1ml of distilled water was added from a dropper carefully to decompose the excess acetic anhydride. An additional 40ml of cold water was added and stirred with a stirring rod to induce crystallisation. The crude product was collected by suction filtration and washed with a little cold water. The crude product is relatively impure; hence it was needed to be purified by recrystallisation. A solvent suitable for this recrystallization process would be a mixture of ethanol and water. The crude product was dissolved in approximately 5ml of ethanol in a 100ml conical flask and heated on a hot plate. To the solution, 30ml of hot distilled water was added in. The solution was then warmed till all solid has dissolved. The solution was allowed to cool. A clean, dry watch glass together with a filter paper was weighed and the weight was recorded. The recrystallised product was obtained by suction filtration using the weighed filter paper. The crystals and filter paper was transferred onto the weighed watch glass and dried in to the oven (100Â °C) for 15 to 20 minutes. The crystals, filter paper and watch glass are then placed in desiccators for 5 to 10 minutes. The dried crystals, together with the filter paper and watch glass were weighed. The weight was recorded and the weight of dried, recrystallised aspirin was calculated. The expected yield of aspirin was calculated from the amount of salicylic acid used. The percentage yield of dried, recrystallised aspirin was also calculated. The melting point of aspirin was determined. Results Mass of salicylic acid Mass of filter paper and watch glass Mass of dried, recrystallised aspirin, filter paper and watch glass Mass of dried, recrystallised aspirinMass of dried, recrystallized aspirin, filter paper and watch glass Mass of filter paper and watch glass Percent yield Number of moles of salicylic acid used (mol wt of salicylic acid = 138) Expected number of moles of aspirin Expected mass of aspirin Percent yield Melting point Temperature Range134. 7 – 136. 8 Appearance The crystals are white and shiny, shaped needle-like. The crystals resemble glass wool. Discussion The results and calculations shows how much acetylsalicylic acid was synthesized compared to how much salicylic acid was used. Since there is a 1:1 ratio between the two, then the amount of salicylic acid used should be equal to the amount of acetylsalicylic acid recovered at the end of the experiment. As the result shows, this is not the case, for 1. 83g of acetylsalicylic acid was harvested when 2. 40g of salicylic acid was used. This could have some effect on the purity; for the melting point of the harvested acetylsalicylic acid which is 134. 7 – 136. 8 was not very close to the theoretical melting point. The percentage yield is only 56. 1%. Since the final product was determined not to be very pure, it is highly likely that less than 1. 83g of the product was acetylsalicylic acid. Further analysis of the product will have to be done to determine exactly how pure the product actually was. There were several problems that could have contributed to the low purity or mediocre percent yield. When dissolving the initial amount of salicylic acid in the solution of acetic anhydride and concentrated sulphuric acid, it did not completely dissolve into the solution, even when it was heated. There could also be loss of product on the filter paper. Some crystals would be stuck onto the filter paper and this might have affected the mass of the crystals. The sample may not have been completely dried out before weighing. This could have a slight impact on the results of the overall yield of aspirin because it was possible that not all of the salicylic acid was synthesized. To determine if this affected the synthesis of aspirin at all, the experiment should have been ran a second time to see if the same thing occurred. Conclusion The experiment did not go completely as expected. The reaction yielded only 56. 1% of its expected product. The purity of the aspirin was not very high, because there might be impurities in the acid used. Reference 1. Henry, Dr. Geneive. 2004. Susquehanna University. Synthesis of acetylsalicylic acid (aspirin). 2. The history of Aspirin, accessed 25th May 2009, 3. History of Aspirin, viewed on 13th Dec 2010, ; http://inventors. about. com/library/inventors/blaspirin. htm; 4. Theory, accessed 15th Dec 2010, 5. Dr. Carman. 2002. University of Nevada, accessed, 15 Dec 2010, ; http://tooldoc. wncc. nevada. edu/aspirin. htm; 6. Synthesis of Aspirin, accessed 13th Dec 2010, 7. Aspirin, accessed 14th Dec 2010,

Primes and Princes

Primes and Princes Primes and Princes Primes and Princes By Mark Nichol This post lists and defines words deriving from the adjective primus, meaning â€Å"first† or â€Å"finest.† premier: first, or earliest; as a noun, a synonym for â€Å"prime minister† premier danseur/premià ¨re danseuse: the first male and female dancer, respectively, in a ballet company premiere: most commonly, a first performance or broadcast of a performing-arts production or the first day of an exhibition (and, rarely, the leading actress in a production); as a verb, pertains to appearing for the first time in a starring role, or the first performance of a performing-arts production prim: neat and trim, or prudish or stiffly formal (and occasionally a verb pertaining to dressing modestly or making a demure expression); prim is also sometimes an abbreviation for primary or primitive prima donna: the first female singer in an opera or a concert; by extension, based on the stereotypical arrogance of such performers, a person who is difficult to work with prima facie: apparent or self-evident (or, in legal usage, legally sufficient to establish a case or a fact); on first appearance primacy: the state of being first, or the office of a high-ranking priest called a primate primal: elemental, natural, or original; less often, first in importance primary: first in order of development or time, or importance or value, or basic, direct, or firsthand; also, relating to something initial or preparatory, or pertaining to a first division, or relating to a preliminary election, as well as derived from ores or not derivable from other phenomena (such as colors); as a noun, something first, dominant, or most proximate primate: any of various species, including humans, apes, monkeys, and related animals; also, the highest-ranking priest in a given area primatologist: one who studies primates primavera: served with fresh vegetables (said of a dish, as in â€Å"pasta primavera†) prime: as a noun, the first hour of the day, the best or most active period or stage, the earliest stage, the best or leading individual or part, the first part of the day, a symbol resembling an apostrophe used for various designations (including units of length, angular measure, or time), or a truncation of â€Å"prime number† or â€Å"prime rate†; as an adjective, best or first, or original (also various mathematical senses); as a verb, apply, load, prepare, stimulate, or supply primer: a short introductory piece of writing, such as an informative article or a reading-instruction book; also, a device used to ignite explosives, a molecule necessary for formation of another molecule, or an initial coating, such as for painting a surface primeval: ancient, basic, or first created, formed, or existing primigravida: one that or who is pregnant for the first time primipara: one that has borne a first offspring or only one offspring primiparous: having a first or only one offspring primitive: original, or earliest or least evolved or in an early stage of development, elemental or natural, or naive or self-taught primo: the first or leading part in an ensemble; as an adverb, in the first place; as an adjective, slang synonym for excellent primogenitor: ancestor or forefather primogeniture: exclusive right of the eldest son to inherit all, or being the firstborn primordial: see primeval primp: dress up (perhaps an extension of prim) primrose: any of various species of plants and their flowers primus: in the Scottish Episcopal Church, the leading bishop; also, the first word of the Latin phrase primus inter pares, meaning â€Å"first among equals† prince: a male member of a ruling family (especially a son of the ruler), a king or other male ruler, a nobleman, or, by extension, one of high rank or standing princeling: a minor prince princess: a female member of a ruling family (especially a daughter of the ruler), a queen or other female ruler, a noblewoman, or, by extension, one of high rank or standing principal: as a noun, a leading person, such as the chief administrator of a school, or something that is most important, or the original amount of money owed; as an adjectival, most important principality: the territory of a prince, or the authority, office, or state of a prince; in plural form, one of various hierarchical categories of angels principle: an assumption, law, or principle considered fundamental, or an explanatory fact or law; a code or rule of conduct, the quality of devotion to principles, or a quality in general; an original source; or an ingredient with a characteristic quality Want to improve your English in five minutes a day? Get a subscription and start receiving our writing tips and exercises daily! Keep learning! Browse the Vocabulary category, check our popular posts, or choose a related post below:100 Words for Facial Expressions50 Latin Phrases You Should KnowHow to Style Legislative Terms