Introduction Acid-base extraction is a very useful technique in organic chemistry. It is used to separate organic compounds from each other. The idea is that most of organic compounds will be more soluble in organic solvents than they are in water (1). The extraction, in its most basic form, will result in unequal distribution of solute between two immiscible (not forming one mixture when added together) solvents (2). Since both of the solvents are immiscible, two separate layers will be formed inside of the separatory funnel (2). Once the two layers have been separated, it is easy to draw off the bottom layer by opening the bottom of the separatory funnel and letting it drain out until the entire lower layer has left the funnel. Being able to determine the identities of the layers is very important in ensuring the appropriate treatment to each liquid after being separated out. It’s important to know that the more dense liquid will be on the bottom of the separatory funnel (2). For this reason, diethyl ether and ethyl acetate are usually used for extraction because both are less dense than the dilute solutions (3). The name acid-base extraction comes from the idea that organic compounds are separate based on their acid-base properties (1). An example of an acid-base extraction based on acid-base properties would be a separation of a mixture containing an organic acid, a base and a neutral compound (2). First, an organic acid will react with a base to
Initially, the entire impure product was mixed with diethyl ether for extraction. Upon mixing, the solution separates into two layers; an organic layer and an aqueous layer. The organic layer contains the desired product. Additional extractions using sodium carbonate solution and sodium hydroxide solution were used as well to ensure removal of undesired molecules. The reason that two layers form is due to the fact that water is immiscible with organic products and diethyl ether meaning that they do not dissolve into one another.
In this experiment, a mixture of unknown #3 was used. That mixture had acid, base, and neutral. We added solvent to the unknown. It is important to know the density of the solvent in order to determine which is the aqueous layer and which is the organic layer. If the solvent that has more density than water, so the organic layer will be the lower layer, while if the solvent has lower density than water, the organic layer will be the upper layer. This will make an error if the determination of the layers was wrong after added the strong acid or the strong base. We added 5% HCl to the mixture in order to separate the base in the aqueous layer and form its salt. Same thing, we add 5% NaOH to the mixture in order to separate the acid and form its salt. In order to recover the base, we add 10% NaOH to the HCl extraction. The result will be salt with a base. Same thing for the acid, in order to recovered it, we added 10% HCl. The reaction will give us salt with an acid. For the neutral, we added sodium sulfate as a drying reagent in order to dry water and separate the neutral part as pure.
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.
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
In the separating funnel, a heterogeneous mixture was formed: resulting in an organic layer (top) and a solvent layer (bottom). This effectively allowed the draining of the solvent, in order to isolate the organic layer, the impure ester (1-pentyl ethanoate)
There are various techniques to separate a mixture of compounds from each other. One of the commonly used way to isolate compounds from a mixture of two compounds is called extraction. This method of extracting two compounds from each other relies on the different solubility of the compounds in two different solvents.
After about 1 minute of shaking, the two layers separated. The organic layer on the top layer (consisted of ethyl acetate and naphthalene) collected for further experiment; by adding Sodium Sulfate into organic phase and filtering the Na2So4 from the solution using the wool. The dried organic layer was weighed to get its mass and the residue of Na2SO4 were rinsed with ethyl acetate under vacuum (rotary evaporator). The acid extract on the bottom layer which is a combination of benzoic acid and NaOH were collected in the 50 mL Erlenmeyer beaker for the recovery of acid.
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 experiment was to use solvent extraction techniques in order to separate a mixture consisting of a carboxylic acid (p-toulic acid), a phenol (p-tert-butylphenol), and a neutral compound (acetanilide). Extraction is the process of selectively dissolving one or more of the compounds of a mixture into an appropriate solvent, the solution that contains these dissolved compounds is called an extract (Manion, 2004).
In this experiment were used three separation techniques: extraction, sublimation and recrystallization. During the first method, 0.70 g sample of salicylic acid-naphthalene mixture was dissolved in 10 ml of diethyl ether. The solution was placed in a separatory funnel and 10 ml of saturated aqueous sodium bicarbonate solution was added to it. After the initial gas was
Dawar Saeed Professor: Nalband Hussain SCC 251 Organic Chemistry II Experiment 1: Separation of a Carboxylic acid, phenol and a neutral compound by Extraction Abstract: Extraction involves dissolving one or more compounds from a solid to a solvent or from a solution into another solvent. Extraction can be used to isolate an organic compound from a mixture or solution. The most common solvent used is 1-mthoxy-2-metylpropane and water. Extraction requires you to mix the solvent in a substance that is more soluble than the solvent which forms two layers when mixed in which you can extract one layer. Introduction: Carboxylic acid and phenol are families of two different organic compounds when reacted with water "yield an excess of hydronium
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.
Oasis HLB, PLRPs, and Hysphere C18 optimization of present SPE was tested. The extraction efficiency of each of these cartridges was estimated from the recovery percentage obtained for each target compound when loading 5 mL of HPLC water spiked with the analytes at 1000 ng/L.