lecture 3
Download
Skip this Video
Download Presentation
Lecture 3

Loading in 2 Seconds...

play fullscreen
1 / 9

Lecture 3 - PowerPoint PPT Presentation


  • 182 Views
  • Uploaded on

Lecture 3. Chapter 5: Extraction Lecture Problem 1 Due Thursday This week in lab: Ch 4: Recrystallization & Melting Point Procedures 1 & 2 Ch 4 PreLab Due Quiz 1 Next week in lab: Ch 4: Procedures 3 & 5 Ch 5: Extraction, Procedure 1 Ch 5 PreLab Due & Quiz 2. Chapter 5: Extraction.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Lecture 3' - tanisha


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
lecture 3
Lecture 3

Chapter 5: Extraction

Lecture Problem 1 Due Thursday

This week in lab:

Ch 4: Recrystallization & Melting Point

Procedures 1 & 2

Ch 4 PreLab Due

Quiz 1

Next week in lab:

  • Ch 4: Procedures 3 & 5
  • Ch 5: Extraction, Procedure 1
  • Ch 5 PreLab Due & Quiz 2
chapter 5 extraction
Chapter 5: Extraction

Extraction

  • “Pulling out” a component from a mixture
  • Used to isolated specific compounds
  • Used to purify a compound
  • Types: Liquid/liquid extraction, solid/liquid extraction

Two day lab:

Procedure 1: Separation of an unknown three-component mixture

Procedure 2: Extraction of caffeine from tea or coffee

chapter 5 procedure 1
Chapter 5: Procedure 1

Possible Unknowns:

Separation of an unknown three-component mixture:

  • Acidic component (CO2H)
  • Basic component (NH2)
  • Neutral component

Acids:

Separate by

acid/base chemistry

Bases:

Once separated and dry, take a m.p. of

each to determine the identity.

Take melting points the following

week.

Neutrals:

chapter 5 procedure 11
Chapter 5: Procedure 1

Example: Separate these three components

1. Use a flow chart to visualize

how the separation will work.

2. See photos/video.

chapter 5 procedure 12
Chapter 5: Procedure 1

Once the separation is complete:

  • Dry each, weigh and calculate % recoveries (assume you started with equal amounts of each)
  • Take a m.p. of each to determine identities
  • Either take an IR of the acidic component OR an NMR of the neutral component
chapter 5 procedure 2
Chapter 5: Procedure 2

Extraction of caffeine:

1. Use tea bags (odd # desks) or coffee bags (even # desks)

2. Steep tea or coffee bags in hot water

3. Extract aqueous solution with dichloromethane (CH2Cl2) to

isolate caffeine

  • Purify caffeine by sublimation
  • Weigh caffeine.
  • Compare caffeine content in tea and coffee with

hoodmate’s data; reference data.

caffeine

chapter 5 procedure 21
Chapter 5: Procedure 2

Extraction of caffeine:

For extraction, use a separatory funnel;

Get a demo from your TA.

*A few, smaller extractions are better

than one big extraction.*

Vent funnel while shaking.

Aqueous layer: tea/coffee solution

Organic layer: dichloromethane/caffeine

Separatory funnel

chapter 5 procedure 22
Chapter 5: Procedure 2

Extraction of caffeine:

Vent funnel while shaking.

Point away from face,

towards back of hood.

chapter 5 procedure 23
Chapter 5: Procedure 2

Once caffeine has been isolated, purify via

sublimation (heat solid  gas  pure solid).

Weigh the isolated caffeine and calculate the amount of caffeine per gram of tea or coffee.

Compare data with hoodmate; reference the data.

ad