Simple Distillation

Summary

This tutorial introduces distillation, a cost-effective method for separating miscible liquid mixtures based on boiling point differences. It outlines the necessary equipment and setup, including a round bottom flask, condenser, and thermometer. The process involves heating to vaporize the component with a lower boiling point, collecting and condensing it into a pure liquid. The script also covers safety precautions, data analysis, and the use of fractional distillation for closely boiling components, culminating in the isolation of isopropyl alcohol from a mixture.

Takeaways

• 🔬 Distillation is a common technique used to separate liquid components of a mixture based on their boiling points.
• 🔑 It requires a significant difference in boiling points between the components for effective separation.
• 🔧 Basic equipment for a simple distillation setup includes a heat source, round bottom flask, three-way adaptor, thermometer, condenser, vacuum adaptor, and collection vessel.
• 📏 The thermometer should be positioned just below the sidearm to accurately measure the vapor temperature.
• 💧 Cold water is run through the condenser to cool the vapor and facilitate the condensation back into liquid form.
• 🔒 Ensuring a tight seal and secure setup is crucial to prevent vapor escape and ensure safety.
• 🌡️ The distillation process involves heating the mixture to a temperature that allows the component with the lower boiling point to vaporize.
• 🥃 In the example given, isopropyl alcohol, with a lower boiling point than water, is distilled off first, leaving the dye in the water.
• 👨‍🔬 Safety precautions are essential when handling flammable substances like isopropyl alcohol, including wearing protective equipment and avoiding fire sources.
• 📊 Data analysis can be incorporated into the experiment by recording the volume of distillate and vapor temperature at intervals.
• 📈 The temperature should increase as more distillate is collected, leveling off once all the alcohol has been separated.
• 🔄 Fractional distillation is mentioned as an alternative method for mixtures with components having very close boiling points, utilizing a fractional column with glass beads for improved separation.

Q & A

What is distillation and why is it used in chemistry labs and industry?

Distillation is a technique used to separate liquid components of a mixture based on their boiling points. It is used because it is an effective and inexpensive method for such separations.

How does distillation differ from extraction?

Distillation is used for miscible liquids with different boiling points, where one component can be boiled without the other. Extraction, on the other hand, involves immiscible solvents that can be separated using a separatory funnel.

What is required for a significant difference in boiling points to allow for effective distillation?

A significant difference in boiling points is required to ensure that only the component with the lower boiling point vaporizes, leaving the other component behind without also vaporizing.

What are the basic components of a simple distillation setup?

A simple distillation setup includes a heat source, a round bottom flask, a three-way adaptor, a thermometer, a condenser, a vacuum adaptor, and a collection vessel such as a beaker or Erlenmeyer flask.

Why is it important to ensure a tight seal in the distillation setup?

A tight seal is crucial to prevent the escape of vapor, which would result in the loss of the component being distilled and could lead to inaccurate results.

How should the thermometer be positioned in the distillation setup?

The thermometer should be placed just below the sidearm of the three-way adaptor to accurately measure the temperature of the vapor.

What is the purpose of running cold water through the condenser?

Cold water is run through the condenser to cool the vapor, causing it to condense back into a liquid phase, which can then be collected.

Why is a boiling chip added to the round bottom flask during distillation?

A boiling chip is added to prevent the solution from boiling violently, which can lead to uneven heating and potential safety hazards.

What safety precautions should be taken when distilling flammable substances like isopropyl alcohol?

Protective equipment should be worn, and care should be taken to avoid fire or sparks to prevent ignition of the flammable substance.

How can data analysis be incorporated into the distillation process?

Data analysis can be incorporated by recording the volume of distillate collected and the corresponding vapor temperature, which can be plotted on a graph to monitor the progress and efficiency of the distillation.

What is fractional distillation and when is it used?

Fractional distillation is a technique similar to simple distillation but uses a fractional column with glass beads to improve separation between liquids with very close boiling points.

Outlines

00:00

🔬 Introduction to Distillation Technique

This paragraph introduces the concept of distillation as a method for separating liquid components in a mixture based on their boiling points. It contrasts distillation with extraction, where immiscible solvents are separated using a separatory funnel. The focus is on the use of distillation in both laboratory and industrial settings due to its effectiveness and cost-efficiency. The process involves heating a miscible liquid mixture to a temperature that allows the component with the lower boiling point to vaporize, leaving the other behind. The vapor is then collected, cooled, and condensed into a pure liquid. Essential equipment for a simple distillation setup includes a heat source, round bottom flask, three-way adaptor, thermometer, condenser, vacuum adaptor, and a collection vessel. The setup process is described in detail, emphasizing the importance of sealing joints, accurate thermometer placement, and securing the apparatus to prevent leaks or accidents.

05:01

🌡 Setting Up and Conducting a Distillation Experiment

This paragraph details the setup and execution of a distillation experiment, specifically focusing on the separation of a 50:50 mixture of isopropyl alcohol and water with added dye. The importance of maintaining a moderate liquid level in the flask and the use of a stirring bar and boiling chip for even heating are highlighted. The paragraph outlines the steps for adjusting the stirring speed, ensuring proper connections, and starting the heating process with caution to avoid violent bubbling. It also emphasizes safety precautions due to the flammable nature of isopropyl alcohol and the need for protective equipment. The experimental procedure includes collecting measurements of distillate volume and vapor temperature, which are used to analyze the efficiency of the separation process. The paragraph concludes with the observation of a clear distillate, indicating successful separation, and a brief mention of fractional distillation for mixtures with closely related boiling points.

Keywords

💡Distillation

Distillation is a separation technique used in chemistry to separate components of a liquid mixture based on their different boiling points. In the context of the video, distillation is the main theme, where miscible liquids with significant boiling point differences are heated to vaporize one component, which is then condensed and collected separately. The script describes a simple distillation setup to separate a 50:50 mixture of isopropyl alcohol and water.

💡Boiling Point

The boiling point is the temperature at which a liquid turns into vapor. It is a critical parameter in distillation, as it determines which component will vaporize first. The script emphasizes the need for a significant difference in boiling points for effective separation, using the example of isopropyl alcohol (82.5°C) and water (100°C).

💡Miscible Liquids

Miscible liquids are those that can dissolve in each other in all proportions. The script contrasts this with immiscible liquids used in extraction, and explains that distillation is suitable for separating miscible liquids with different boiling points.

💡Separatory Funnel

A separatory funnel is a piece of laboratory equipment used to separate immiscible liquids. The script mentions it in the context of extraction, where it is used to separate two immiscible solvents, unlike the miscible liquids in distillation.

💡Condenser

A condenser is a device used to cool vapors back into a liquid state. In the script, the condenser is a crucial part of the distillation setup, where the vapor from the boiling liquid is cooled and condensed before being collected as distillate.

💡Round Bottom Flask

A round bottom flask is a type of laboratory flask with a rounded bottom, often used for distillation. The script describes placing the flask on a support over a heat source and using it to contain the mixture being distilled.

💡Heat Source

A heat source, such as a hot plate or Bunsen burner, is necessary to provide the heat for the distillation process. The script specifies the need for a heat source to heat the mixture to boiling and emphasizes the importance of even heating to avoid violent bubbling.

💡Thermometer

A thermometer is used to measure temperature. In the script, it is used to monitor the temperature of the vapor, ensuring that the distillation occurs at the correct temperature to separate the desired component.

💡Vapor

Vapor refers to the gaseous state of a substance that is normally a liquid at room temperature. The script describes the process of heating the mixture until the liquid with the lower boiling point turns into vapor, which is then condensed and collected.

💡Fractional Distillation

Fractional distillation is a more refined method of distillation used when the boiling points of the components in a mixture are very close. The script briefly mentions this technique, noting that it involves a fractional column with glass beads to improve separation.

💡Protective Equipment

Protective equipment is necessary to safeguard individuals from potential hazards during experiments. The script specifically warns about the flammability of isopropyl alcohol and the need for protective gear to prevent eye irritation and skin damage.

Highlights

Introduction to distillation as a separation technique based on boiling points.

Difference between distillation and extraction, emphasizing miscible liquids with different boiling points.

Explanation of the process where heating causes the liquid with a lower boiling point to vaporize.

Description of the simple distillation setup with necessary equipment and their functions.

Instructions on assembling the distillation apparatus, including the use of a round bottom flask and three-way adaptor.

Importance of sealing the setup to prevent vapor escape and the method to ensure a tight seal.

Placement and function of the thermometer for accurate vapor temperature measurement.

Technique for securing the flask and condenser to prevent displacement during the distillation process.

Mechanism of cooling the condenser using cold water to facilitate vapor condensation.

Setup completion with the collector in place to gather the distillate.

Emphasis on checking the setup for tight seals and loose connections before starting the distillation.

Selection of a 50:50 isopropyl alcohol and water mixture for demonstration with dye for visual confirmation of separation.

Safety precautions and protective equipment required when handling flammable substances like isopropyl alcohol.

Data analysis component introduced with the collection of measurements for each milliliter of distillate.

Observation of temperature changes and their relation to the composition of the mixture during distillation.

Guidance on when to stop collecting distillate based on the boiling point of the target compound.

Demonstration of the clear distillate compared to the colored mixture, indicating successful separation.

Introduction to fractional distillation for mixtures with components having very close boiling points.

Conclusion summarizing the distillation process and its outcome in isolating isopropyl alcohol.

Transcripts

Over

the past several tutorials we’ve performed a few separation techniques, those being filtration

and extraction.

Now let’s look at another one, distillation.

This is a technique that is very common in chemistry labs as well as industry, as it

is an effective and inexpensive way to separate liquid components of a mixture by virtue of

their boiling points.

So this is different from extraction, where the two solvents were immisicible and we could

easily separate them with a separatory funnel.

Here we have a mixture of miscible liquids that have sufficiently different boiling points,

such that we can boil one and not the other.

This is achieved by heating the mixture to a temperature above the boiling point of one

component but below the boiling point of the other, so that the liquid with the lower boiling

point turns into vapor, leaving the other liquid behind.

We can then collect, cool, and condense the vapor into a pure liquid on the other side

of the condenser in a receiving flask.

For this to be achieved, a significant difference in boiling point is required, otherwise too

much of the other component will vaporize as well.

For a simple distillation setup, we’ll need a heat source such as a hot plate or Bunsen

burner.

We’ll also need a round bottom flask, a three-way adaptor like this one, a thermometer

adaptor, a thermometer, a condenser, a vacuum adaptor, and something with which to collect

the condensing vapor, also called the distillate, such as a beaker or Erlenmeyer flask.

We’ll also need a support adaptor for our round bottom flask, and some connector clips.

Lastly, we’ll need ring stands and some clamps.

To build the setup, let’s start with our round bottom flask.

We’ll place it on a round bottom support and put that on a hot plate.

On top of the flask, we can add the three-way adaptor with a side arm like this.

We’ll then connect the thermometer on top using a thermometer adaptor.

We need to make sure that everything is sealed so that our vapor does not escape.

You can add some grease to the joints and turn them so everything fits well.

Your thermometer should be placed at a level that is just a bit lower than your sidearm

to get an accurate measurement of the temperature of the vapor.

Let’s then secure our flask by clamping it at the top like this.

Now on this arm of the three-way adaptor, we can add the condenser.

Since the condenser tends to fall off, as gravity will cause it to slide down, we also

need to secure it.

We can do that by clamping our vacuum adaptor like this and connecting it to the condenser.

We now have support on both sides.

To keep the condenser cool, we will run cold water through this outer chamber.

The vapor will move through the inner section of the condenser, and as its being cooled

by contact with the glass that has been cooled by the cold water in the outer section, it

will begin to return to the liquid phase.

To enable the flow of cold water, on the bottom part of the condenser, let’s connect a hose

that brings in cold water from the tap.

Then connect another hose where the water will exit on the top, and just let that empty

into the sink.

Let’s then finish the setup by adding our collector underneath the end of the condenser

to collect the distillate as it drips out.

In this particular example we are going to be using a graduated cylinder here because

we want to measure the volume of our distillate as time goes by.

So this is our complete setup.

Make sure you examine every joint to ensure that you have a tight seal.

Also check your clamps and adaptors to ensure that nothing is loose.

We can further secure our setup by adding clips that look like this.

These can be used to clamp all the joints together so that the glassware does not separate.

You can now turn on the cold water and make sure that it flows smoothly through the condenser.

We are now ready to start the distillation.

Today we will be distilling a 50:50 mixture of isopropyl alcohol and water with some dye

added to it.

That will give our solution some nice color.

The boiling point of isopropyl alcohol is 82.5 degrees Celsius, while water’s is 100,

so the alcohol is the substance that will vaporize here.

Additionally, because the dye is much more soluble in water than in the alcohol, our

distillate will be clear, leaving all of the dye behind in the water, acting as a visual

confirmation that separation is occurring.

When adding your solution to the round bottom flask, the liquid level should be around halfway

up the flask or lower, as we do not want any liquid to splatter up into the condenser.

Next, let’s add a stirring bar so that we get even heating in our mixture.

We can also add a boiling chip to make the mixture boil more calmly.

Let’s turn on the stirring function and start out by stirring the solution at a slow

rate like this.

You don’t want it to go too slow or too fast, so let’s put this one at around 5.

Be sure to experiment with your stirring function, as different instruments will give you different

stirring speeds.

We can then double-check that everything is connected and that our water is running through

the condenser.

Now let’s turn on the heater.

We’ll turn this up to a medium level to get even heating.

Do not use a high temperature because the solution will start bubbling violently when

it boils.

If that happens, lower the temperature, or remove the heat source completely and wait

until everything cools down before you start again.

Also the discrepancy in the two boiling points is not enormous, so we want to make sure we

don’t heat to a temperature so high that both substances end up boiling.

If you set up the heating and stirring correctly, the mixture should soon come to a nice even

boil.

Vapor will rise up into the three-way adaptor, where it will start condensing.

Eventually, vapor will start collecting in the top arm of the condenser.

The vapor will then travel through the condenser where it will begin to condense, and this

liquid will start falling into the collection vessel.

The isopropyl alcohol being collected is a highly flammable substance that can cause

serious eye irritation and damage to your skin, so if doing distillation of this type,

make sure you wear protective equipment and stay away from fire or sparks.

For this particular experiment, to add a component of data analysis, we can also collect some

measurements.

For every milliliter of distillate collected, write down the total volume collected and

the temperature of the vapor as shown by the thermometer.

We should keep collecting the distillate until we get the amount of alcohol we originally

measured and added to the mixture.

The temperature should go up as the volume of distillate goes up.

This is because the composition of the mixture changes as more of one component is vaporized

and removed.

When all the alcohol has been collected, the condensation should stop, and the temperature

should stop rising.

A graph of your data for a simple distillation should look like this.

The temperature goes up as more distillate is collected, and it will level off after

we’ve removed all the alcohol.

If you know the identity of your target compound as we do in this case, you should collect

your distillate until you get to a range that is slightly above its boiling point.

You can then change the flask when the temperature goes much higher than that.

This is to avoid impurities that have a boiling point higher than your desired product, such

as water in this case.

And with that we have completed a distillation, in which we isolated isopropyl alcohol from

the rest of the mixture.

And as expected, we can see how clear this is compared to our colored mixture.

When the boiling points of the components in the mixture are very close, we can also

use another method called fractional distillation.

This technique is similar to a simple distillation except that we use a fractional column for

the vapors to travel through before they hit the condenser.

This column contains layers of glass beads that improve the separation between the liquids

that are being separated.

But for today, that’s all we need to know about distillation.

Let’s move forward and examine some other techniques.