Introduction
The students will utilize distillation equipment to extract pure Ethyl acetate through the distillation method. Distillation involves vaporizing a liquid mixture in one vessel and then condensing the vapors into the receiver.
Experimental procedures
Safety Information
When handling the liquid, it is crucial to exercise caution and avoid inhaling its vapors due to their potential danger. It is also important to protect your skin from heat-generating equipment to prevent burns. Remember that EtoAc is highly flammable, can cause skin dryness, and excessive inhalation may lead to dizziness. Therefore, it is crucial to handle this substance with care.
Stepwise Procedures
- We will be using 10 mL of the ethyl acetate mixture. Measure accurately and record the volume by using the 10mL graduated cylinder.
- Use 25mL round bottom flask in your organic kit. Make sure to use 2-3 boiling chips and stopcock grease on all ground class joints.
- Get out the condenser from the organic kit. Also get 3 way connector and the vacuum adapter. You will need to receive in a 10mL clean graduated cylinder. Also get 2 rubber hoses.
- Get the heating mantle and place the 25mL round bottom flask with the ethyl acetate and boiling chips in the mantle.Secure the flask. Then attach the 3 way connector to the top of the flask using stopcock grease. On top of the 3 way connector, place the thermometer adapter also by using the grease. Use blue clamp to secure the thermometer adapter. Use a Hg thermometer to record the temperature. Make sure the top of the Hg bulb is even with the bottom of the sidearm of the 3 way connector. Attach the condenser using a stop cock grease and a blue clamp to secure the condenser. Attach rubber hoses to the condenser. One hose should connect from the water source to the bottom nipple of condenser and the other hose should connect from the top nipple of the condenser and drain into the sink. Vacuum adapter should be attached to the bottom of the condenser using the grease with blue clamp to secure it. Receive into 10mL graduated cylinder.
- Once you have everything, get instructor’s approval to go ahead with the experiment.
- Begin heating by setting the variac to high or 9. Collect ethyl acetate until the stillpot becomes almost dry. Record the temperature when you have received 5 mL of sample and continue heating. This temperature should be the bp of the purified ethyl acetate. g
- When finished, record the volume of purified ethyl acetate and save some of it in a vial. Label the vial with name and simple distillation and place them on the yellow cabinet.
- In Results section, calculate the % recovery of purified ethyl acetate.
- Clean up. Get approval from instructor before putting the organic kit back into the box.
Theory and Conclusion
During the lab, we employed a method called simple distillation, which involves separating volatile substances by exploiting their distinct physical properties. There are two types of simple distillations: one involving a volatile liquid with a nonvolatile impurity, and the other involving two liquids with a temperature difference of approximately 50 to 60 degrees Celsius in their boiling points. In the experiment, we had the former scenario, where one substance vaporized and stayed in the boiling pot. In the latter scenario, one liquid can be distilled at a low temperature while the other remains nonvolatile and stays in the boiling pot until its volatile phase is achieved.
The process of simple distillation is straightforward, but assembling all the components can be challenging. To achieve a high percentage of recovery, it is crucial to set up all the glassware and parts correctly, ensuring tight connections with stopcock grease and blue clamps. The placement of the mercury thermometer is especially critical, as an improper height will result in inaccurate temperature readings and lower recovery percentages.
In order to achieve a high percent recovery, it is important to correctly position the thermometer by aligning the top of the bulb with the bottom of the stillhead’s sidearm. This allows for proper moistening of the entire thermometer bulb by the vapors produced from the distillate. Additionally, a thorough understanding of boiling point elevation was required for this experiment due to the composition of the solution, which included EtoAc and Methyl violet.
Boiling point elevation is the occurrence where the boiling point of a solution is higher than that of the pure solvent. This is due to the utilization of two solvents with differing boiling points, causing an increase in the pot temperature. Consequently, the pot temperature will surpass that of the surrounding stillhead. The boiling point of EtoAc is approximately 78°C, and my experiment yielded a recorded boiling point of 79°C. This outcome substantiates the correct placement of the thermometer.
The experiment involved the use of boiling chips, which are porous materials made from carbon, glass, and alumina. Boiling chips are essential in preventing bumping, which occurs when a liquid substance is heated to its boiling point and releases large bubbles of vapor in a violent manner. It is recommended to employ boiling chips during any distillation process to avoid these disruptive eruptions.
Although not achieving a 100% recovery, the presence of a small lump in the condenser caused the EtoAc sample to collect before flowing into the other flask. Heating was stopped once the liquid sample was nearly depleted in the 25mL round flask. This resulted in some remnants remaining in the original flask, contributing to the lack of 100% recovery. However, despite these factors, I managed to recover 91% of the distillate.
