Lecture 2 Green Chem, Dehydration 012810

Lecture 2 Green Chem, Dehydration 012810 - Chem 258...

Info iconThis preview shows pages 1–13. Sign up to view the full content.

View Full Document Right Arrow Icon
Chem 258 – Lecture #2 Dehydration of Cyclohexanol to Make Cyclohexene OH H 3 PO 4 H 2 O
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Reminder l CAN bring handout to lab l DON’T need a step-by-step procedure l Before you enter lab: ¡ Your notebook should have Objective, Reaction, Reagent Table with densities, boiling and melting points, molecular weights, amounts to add and theoretical yield l Chemical Characterization Data ¡ www.acros.com ¡ www.sigmaaldrich.com
Background image of page 2
Lab 2 - Techniques l Reflux l Neutralization l Distillation (Boiling points of liquids) l Extraction l Salting Out l IR Spectroscopy
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Oh, and one more thing… l Great job in lab this week!!! l h
Background image of page 4
Click to edit Master subtitle style Catch Phrase of the Week: “Like Dissolves Like”
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
CAUTION!! – H3PO4!!!!! l Phosphoric acid = corrosive l Bad, bad, bad! ¡ How bad? l Two sets of gloves ¡ Wear them when you dispense the acid!!
Background image of page 6
Reaction Mechanism l the strong acid protonates the hydroxyl group l water can leave as a neutral (better leaving group than OH-) l H+ will leave, double bond is formed “B:” means something basic that is removing a proton.
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Distillation l Distillation occurs when you vaporize a substance and condense it back into liquid form ¡ EXCELLENT TECHNIQUE FOR SEPARATING LIQUIDS ¡ Composition of the liquid and the vapor are different ¡ That is why you can separate mixtures via distillation l separation of a product from impurities or isomers based on boiling point ¡ the compound must be stable at its boiling point l decomposes - can’t use distillation to purify ¡ liquid vapor (heat or vacuum) ¡ vapor liquid (condensation)
Background image of page 8
Distillation Photo: http://orgchem.colorado.edu/hndbksupport/dist/images/wwdist2.jpg
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Types of Distillation in Lab 2 l Simple distillation ¡ pure substance – no solvent needed! ¡ separate it from very minor impurities or inhibitors l Fractional distillation ¡ one substance is separated from another when both are present in high quantity
Background image of page 10
Types of Distillation Columns l Packed Columns ¡ increased surface area = better separation l Glass beads l Glass helicies l metal sponge (like a Brillo pad or steel wool) Careful of interactions l Water-cooled condensers ¡ tube in a tube ¡ spiral glass in a tube ¡ glass indents (Vigreux column) l “Water goes – in the bottom, out the top”
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
l the longer the column = the better the separation l the smaller the amount of material that comes over into the condenser, the longer the distillation will take
Background image of page 12
Image of page 13
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 06/28/2010 for the course CHEM 258 taught by Professor Taylor during the Spring '10 term at Wesleyan.

Page1 / 39

Lecture 2 Green Chem, Dehydration 012810 - Chem 258...

This preview shows document pages 1 - 13. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online