Extraction: Acid and Base Separation and Isolation
Kaleigh Conway
Chemistry 2270 Laboratory, Section 017
Instructor: Mudithangani Kolambage
October 11, 2017
Abstract: The purpose of this lab was to investigate the method of extraction as a means of isolating pure compounds. In this experiment, the acid-base extraction method was used on a mixture composed of three separate components: an acid, a base, and a neutral component. The extraction solvent used was diethyl ether. Through sequential acid-base reactions where aqueous 10% NaOH and aqueous 10% HCl were used in a separatory funnel, the three components were extracted, isolated and then recovered through precipitate reverse reactions using 10% NaOH and concentrated HCl. Once the components were isolated and recovered, a melting point analysis was performed and these values were then compared to the values in the laboratory handout in order to identify the compounds. Percent yield of each compound was also calculated. It was found that the mixture contained Benzoic Acid with a melting range of 121.6-122.9 oC and a percent yield of 292%, Meta-nitraniline with a melting range of 111.4-112.2 oC and a percent yield of 204%, and Biphenyl with a melting range of 70.6-73.5 oC with a percent yield of 128%.
Introduction:
Goals:
1.
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To isolate different components of a substance through extraction
2. To calculate the percent yield of each component that was recovered
3. To identify the different components of a substance using melting
This lab could have contained errors. The errors could have happened when performing the lab. Some of the possible errors in this lab are:
The objective of this extraction experiment was to achieve a comprehensive understanding, as well as master the practice, of the technique of separating various individual components of a compound.
There are millions of different organic compounds. Most of them are found in mixtures and in order to achieve a pure form they need to be separated, isolated, and purified. However, there are endless numbers of possible mixtures, which make it impossible to have a pre-designed procedure for every mixture. So chemists often have to make their own procedures. The purpose of this experiment was to prepare the student to the real world by them designing their own procedure which will help them understand the techniques of separation and purification better. The goal was to extract two of the components of the
The problem that was trying to be solved in this study deals with analyzing unknown solutions. In this particular case, a chemical company has several unknown solutions and to correctly dispose of them they need to know their properties. To figure out the properties several qualitative tests were performed throughout the study (Cooper 2012).
Experiment 4A: Determination of a Partition Coefficient for Benzoic Acid in Methylene Chloride and Water, and Experiment 4B: Solvent Extraction I: Acid-Base Extraction Using the System Benzoic Acid, Methylene Chloride, and Sodium Bicarbonate Solution
This experiment combined all the knowledge of the previous labs performed throughout the semester. An unknown mixture containing an organic acid or base and an organic neutral compound in nearly equal amounts needs to be separated to its separate components. An understanding of solubility, extraction, crystallization and vacuum filtration is necessary in order to
The purpose of this virtual lab is to observe the acid-base balance in the urinary system by how PCO2 and blood pH affect the H+ and HCO3- in the urine. The renal compensation is a mechanism that shows the kidneys manage to change pH in correct way if the respiratory system is not healthy. The kidneys are two organs that help remove wastes and extra fluids out of the body. The acid-base balance is when the blood need to keep the balance of
Abstract: One mixture of two unknown liquid compounds and one mixture of two unknown solid compounds were separated, isolated, purified, and characterized by boiling point. Two liquid unknowns were separated, isolated, and purified via simple distillation. Then, the process of an acid-base extraction and washing were used to separate two unknown compounds into two crude compounds: an organic acid and a neutral organic compound. Each crude compound was purified by recrystallization, resulting in a carboxylic acid (RCO2H) and a pure organic compound (RZ). The resulting mass of the pure carboxylic acid was 1.688g with a percent recovery of 31.80%, the boiling range was 244-245 °C, and its density was 2.0879g/mL. The resulting mass of the pure organic solid was 2.4902g with a percent recovery of 46.91%, the boiling range was 52.0-53.4°C, and its density was 1.5956 g/mL.
Dispense .5 mL water into the already weighed conical vial, replace cap and face insert on its down side.
Three grams of a mixture containing Benzoic Acid and Naphthalene was obtained and placed in 100 ml beaker and added 30 ml of ethyl acetate for dissolving the mixture. A small amount (1-2 drops) of this mixture was separated into a test tube. This test tube was covered and labelled as “M” (mixture). This was set to the side and used the following week for the second part of lab. The content in the beaker was then transferred into separatory funnel. 10 ml of 1 M NaOH added to the content and placed the stopper in the funnel. In the hood separatory funnel was gently shaken for approximately one minute and vent the air out for five seconds. We repeated the same process in the same manner one more time by adding 10ml of 1M NaOH.
In the first acid extraction of benzocaine, the compound was dissolved in the organic solvent of dichloromethane. When the mixture was shaken with HCl, benzocaine’s amine group gained a proton and became more soluble in water than dichloromethane. This allowed the newly formed hydrochloric salt to migrate to the aqueous layer. However, the addition of NaOH to the acidic aqueous layer regenerated benzocaine by deprotonation, making it insoluble in the aqueous layer. The precipitation of an ionic salt was therefore recovered by vacuum filtration and had a tested melting point range of 85.1C-87.4C compared to 88C-90C, the literature melting point of benzocaine. The similarity in melting point ranges, but low percent yield of 30.37% proves that the extract was somewhat successful. Lower yields may be the result of spillage performed in the lab. In the second basic extraction, the organic layer now included benzoic acid and benzamide. When treated with NaOH to deprotonate benzoic acid, the newly formed sodium benzoate transitioned to the aqueous layer as a sodium salt. Benzoic acid is regenerated once again after the addition of HCl and became insoluble in the aqueous layer after protonation. Its precipitation was then filtered out for a 65.87% recovery. Compared to its literature melting point of 122.41C, the resulting 120.9C-123.5C melting range of the sample also supports the accuracy of the separation due to its similarities and high percent yield. In conclusion, the usage of base and acid liquid extraction was mostly successful in this experiment because it was able to efficiently and properly isolate the impure mixture into two separate components of benzocaine and benzoic acid. By performing the techniques of extraction and vacuum filtration, the similarities between literature and tested
The purpose of this lab was to determine the pH and total acidity of grape juice and wine. A second purpose was to experimentally determine the pKa of a monoprotic weak acid, polyprotic weak acid, as well as, a free amino acid, alanine.
Objective: The objective of this experiment is to use acid-base extraction techniques to separate a mixture of organic compounds based on acidity and/or basicity. After the three compounds are separated we will recover them into their salt forms and then purify them by recrystallization and identify them by their melting points.
An acid-base titration is the determination of the concentration of an acid or base by exactly neutralizing the acid/base with an acid or base of known concentration. This allows for quantitative analysis of the concentration of an unknown acid
Acids and bases are very important. We clean with them, we eat them, and we use them to help in chemistry. The ions who are the cause of acidic properties is H+ ions, or protons, and for basic properties, it's the OH- ions, or hydroxide ions. all of that is based on a theory called the 'dissociation of water' (which is H2O--> H+ + OH-). So the more H+ there is in a solution, the more acidic the solution is, and the less H+ there is, the more basic it is. That is why there is H+ in solution factors on the pH scale. The more protons present at one time means the pH scale decreases, and the H+ present goes down. The pH scales job is to measure the acid and base levels of a substance and how strong they are. The numbers on the scale go from 1 to 14, with 1 containing the most hydrogen ions and 14 having the least.