Microscale Recrystallization Lab Report

The results from Calculations 1 and 2 can be utilized in Eq. 3 to determine the final percent yield for the experiment, and this is shown in Calculation 3.

To calculate the percent by mass, we are to take the mass in grams of a particular salt and divide it by the mass in grams of the original sample, and then multiply it by 100.

In experiment two, 1.48g of the unknown solid was recovered. From this mass, it was determined approximately 30mL of boiling water was needed for crystallization of acetanilide and about 121mL for phenacetin. Phenacetin would require more solvent because it is less

The recrystallization technique utilizes the ability of a compound to dissolve within a hot solvent and produce a solution. As this solution cools, the solute reforms without impurities in a crystal lattice structure.1 For this to work properly, an appropriate solution that will not dissolve the solute at low temperatures, but will at high temperatures, must be used.1 There is no single solvent that will work well for every solute’s recrystallization; different solvents are better suited for some solutes than others.2 Some impurities that do not dissolve within the solvent can be filtered out while the solution is still hot, while other impurities that readily dissolve within the solvent shouldn’t recrystallize with the pure substance (as they are not concentrated enough to

The product was placed in a Craig tube and several drops of hot (100°C) solvent (50% water, 50% methanol, by volume) was added and heated until all of the crystals dissolved. The Craig tube was plugged and set in an Erlenmeyer flask to cool. Crystallization was induced once the mixture was at room temperature by scratching the inner wall of the tube. It was then placed into an ice bath for ten minutes until crystallization was complete. The tube was then

The product was then suspended in 2 ml of water with a stir rod in a 50 ml Erlenmeyer flask and heated to boiling. Water was added in one milliliter increments until all the product was dissolved (18 ml added total). The saturated solution was allowed to slowly cool, and gradual white crystal formation was observed. Recrystallized product was collected once more by suction filtration with the Hirsch funnel once crystallization ceased. Collected product dried on a watch glass for a week, weighed 0.14 g (1.2 mmol), and the melting point was 139°-141°

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.

When we were mixing the filtration and letting it vent periodically, we lost some of it. So our percent recovery is as follows:

First, we added water to the graduated cylinder to 20 mL. Then, placed the unknown substance in the water, the water increased and measured 25 mL. The volume was determined by subtracting 20 mL from 25 mL. The volume equaled 5 mL for the unknown substance. Next, we filled the water to 20 mL in the graduated cylinder. Then, placed aluminum in the water, the water increased and measured 25 mL. The volume was determined by subtracting 20 mL from 25 mL. The volume equaled 5 mL for aluminum. After that, we added water to the graduated cylinder to 20 mL. Then, placed the zinc in the water, the water increased and measured 22.5 mL. The volume was determined by subtracting 20 mL from 22.5 mL. The volume equaled 2.5 mL for zinc. Last, we added water to the graduated cylinder to 20 mL. Then, placed lead in the water, the water increased and measured 24 mL. The volume was determined by subtracting 20 mL from 24 mL. The volume equaled 4 mL for

The purpose of Experiment 6 - Part 1, was to use electrophile addition to synthesize 1,2‐dibromo‐1,2‐diphenylethane from (E)-1,2-diphenylethene. The final product was correctly identified by the use of TLC and melting point determination. The final product was meso-1,2‐dibromo‐1,2‐diphenylethane. Figure 1. Reaction for Experiment 6, Part 1. Created by Chem Doodle.

Next, the layer was dried with anhydrous sodium sulfate and exchanged to round base flagon to set up for basic refining. The round base jar is discharged out and set up for sublimation. As a result of the choking of time, the blend was not ready to sufficiently warm to get a nice sum on the tube to gather for weight and dissolving point. Along these lines, I was not ready to inspire enough to finish dissolving point. The softening point was taken from somebody in lab whose dissolving point was between 88-100°C. The measure of grams recouped was .07g. That is a modest number which prompts a low percent yield and is expected to not having the capacity to warm for a drawn out stretch of time because of the test being longer than

The solution was subsequently arranged into a reflux apparatus which included a wet paper towel in order to prevent vapor loss. The solution was refluxed at a temperature ranging from 180°C-185°C for thirty minutes via sand bath. The contents of the micro-test tube were then cooled to room temperature followed by an ice bath in order for crystals to form. The crystals were then collected via suction filtration using a Hirsch funnel. The product was washed with ice-cold xylene (3

Identification of Unknown Organic Compounds by Melting Point, Boiling Point, Infrared and Nuclear Magnetic Resonance Spectroscopy Background and Method In the previous labs we were experimenting with different methods so that we can find different physical properties of the known compound. However, this lab report is a little different as it gives us two unknown compounds where we have to use the prior knowledge we have gotten in the other labs to ensure that we know exactly how to ultimately find the correct molecular structure of the unknown compounds. Therefore in this lab, we had to perform elemental analysis, boiling point, infrared (IR), Nuclear Magnetic Resonance Spectroscopies (NMR) and melting point. Thus, the main objective of this lab was to ensure that the students knew how apply the techniques from the previous labs and interpret the spectroscopy data to formulate the correct structure of the compound.

The week after, a recrystallization was performed on the previous week’s crude product. The product ethereal solution was first heated on a steam bath until dry. During the heating, a beaker of methanol was collected and also placed on the steam bath. Once the product was dry, it was cooled to room temperature and then placed in an ice-water bath. The now boiling methanol was added to the crude crystals and a recrystallization was performed. Once completed, the now purified product was collected via Buchner vacuum filtration and stored in drawer to dry for a week. Afterwards, a melting point range of the purified product was obtained by using a Mel-temp apparatus. Lastly, an

Recrystallization was done to remove impurities from the sample. The percent recovery of benzoic acid during recrystallization is 23.02%. The difference between the pure and impure samples was observed by comparison of melting points. It was found that impure sample had a lower and wider melting point range of 120.1-122.2 (C). The pure sample melting point range was 121.3-122.5 (C). These ranges helped determine purity by comparing the known melting point of pure benzoic acid.