Formal Report on Re Crystallization
RECRYSTALLIZATION
Group Medical Technology Organic Chemistry Laboratory
ABSTRACT
Recrystallization is one of the simplest and most widely used technique for purifying organic solids through the differences in solubility at different temperatures. It is also the process in which the solid to be crystallized is dissolved to either a hot solvent or a hot solvent mixture and is cooled in a solution.In this experiment, acetanilide, the crude product of acetylation of aniline and acetic anhydride, was used as the pure organic compound. Crude acetanilide underwent crystallization process using the preferred recrystallizing solvent, water. The crystallization process was when crude acetanilide was placed in hot water bath and was cooled after in an ice bath which would then yield to the formation of crystals of pure acetanilide. The percentage yield form the crude acetanilide was 94.59%. The percentage recovery of the experiment was 46.43%.
INTRODUCTION
Organic compounds that are synthesized in laboratories or isolated from natural recourses are often tainted by impurities. Different purification methods can be used to remove the impurities present in a compound. One example of these is recrystallization. It is a method which purifies organic solids base on its solubility. It is also a process which dissolves solid to be crystallized in a hot solvent mixture and cools it afterward. The dissolve solid decreases insolubility at a low temperature and separates as it cools resulting to small seed crystals. Crystallization was done twice. During the first crystallization a crude product would be formed which would still have some impurities that needs to be remove. This was the reason for doing crystallization for a second time yield to a pure product which contained fewer or no impurities at all. The level of purity of the product can be checked through its melting point range. Formation of crystals was due to the difference insolubility of the
Group Medical Technology Organic Chemistry Laboratory
ABSTRACT
Recrystallization is one of the simplest and most widely used technique for purifying organic solids through the differences in solubility at different temperatures. It is also the process in which the solid to be crystallized is dissolved to either a hot solvent or a hot solvent mixture and is cooled in a solution.In this experiment, acetanilide, the crude product of acetylation of aniline and acetic anhydride, was used as the pure organic compound. Crude acetanilide underwent crystallization process using the preferred recrystallizing solvent, water. The crystallization process was when crude acetanilide was placed in hot water bath and was cooled after in an ice bath which would then yield to the formation of crystals of pure acetanilide. The percentage yield form the crude acetanilide was 94.59%. The percentage recovery of the experiment was 46.43%.
INTRODUCTION
Organic compounds that are synthesized in laboratories or isolated from natural recourses are often tainted by impurities. Different purification methods can be used to remove the impurities present in a compound. One example of these is recrystallization. It is a method which purifies organic solids base on its solubility. It is also a process which dissolves solid to be crystallized in a hot solvent mixture and cools it afterward. The dissolve solid decreases insolubility at a low temperature and separates as it cools resulting to small seed crystals. Crystallization was done twice. During the first crystallization a crude product would be formed which would still have some impurities that needs to be remove. This was the reason for doing crystallization for a second time yield to a pure product which contained fewer or no impurities at all. The level of purity of the product can be checked through its melting point range. Formation of crystals was due to the difference insolubility of the
References: From books: [1]. Ault (1983). Techniques & Experiments fo Organic Chemistry (4th Ed.). Massachusets: Ally & Bacon Incorporated. [2]. Martin & Gilbert (2011). Organic Laboratory Experiment (5th Ed.). Boston: Cengage Learning. [3]. University of Santo Tomas. Faculty of Pharmacy. Organic Chemistry Group. (2014). Laboratory Manual in Organic Chemistry (Revised Edition). Quezon City: C&E Publishing Inc. From websites: [4]. ACETANILIDE (N-PHENYLACETAMIDE). (n.d.). Retrieved September 28, 2014 from http://chemicalland21.com/lifescience/phar/ACETANILIDE.htm [5]. ACETIC ANHYDRIDE (ACETYL ETHER). (n.d.). Retrieved September 28, 2014, from http://chemicalland21.com/petrochemical/ACETIC%20ANHYDRIDE.htm [6]. PURIFYING ACETANILIDE BY RECRYSTALLIZATION. Retrieved September 24, 2014,from http://www.cerlabs.com/experiments/1087540703X.pdf [7]. RECRYSTALLIZATION.Retrieved September 27,2014 from http://chemistry.barnard.edu/orgolab/lab2 and http://web.centre.edu/muzyka/organic/lab/24_recrystallization.htm