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Prelab Lecture

SN1 (Solo Exp#2)

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BACKGROUND READING:Solomons and Fryle Chapter 6 (Sub/Elim Rxns)

Techniques Weights/Measures, Filtration, Melting Point, TLC

Videos Filtration Vacuum, Melting Point, TLC

CHEM 212 PRELAB CYCLE 1 SN1

Laura Pavelka

[email protected]

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SN1 Reaction

PURPOSE: convert an alcohol to an alkyl chloride via an SN1 mechanism

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SN1 Reaction nucleophilic substitution

reaction with unimolecular rate

determing step (RDS)- RDS carbocation formation

tertiary carbocation

LG Nu

NuRDS

3 > 2 >>>> 1


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SN1 Experiment

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Acid Catalyzed SN1:


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IR Spectroscopy

4CHEM 212 PRELAB CYCLE 1 SN1

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Solubility and

Thin Layer Chromatography (TLC)

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Cl

Cl

vs.


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Overview SN1 Lab

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PURPOSE: convert an alcohol (2,5dimethyl2,5hexandiol) to an alkyl

chloride (2,5dichloro2,5dimethylhexane),

learn new analysis techniques IR spectroscopy, TLC

2,5dimethyl2,5hexanediol 2,5dichloro2,5dimethylhexane

Analysis: Melting Point, IR Spectroscopy, Solubility, TLC


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1. SN1 Reaction


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2. Melting Point

MELTING POINT

physical property of a compound, index of purity

fixed value reported as a RANGE

CRUDE PURIFIED

MP VALUE depressed close to

literature

MP RANGE BROAD

(> 3oC)

NARROW

(1 3 oC)

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Cl

Cl


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2. Melting Point


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3. IR Spectroscopy

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Cl

Cl


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5. Thin Layer Chromatography

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Cl

Cl


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% Yield

CRUDE Theoretical

MASS 1.5 g 3.0 g

% YIELD (crude) = mass crude x 100% = 1.5 g x 100% = 50 %

theoretical 3.0 g

TOTALLY FICTICIOUS VALUES


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Safety & Waste Disposal

CHEM 212 PRELAB CYCLE 1 SN1 14

Special Safety Considerations:

Hydrochloric acid (HCl) Hazardous in case of skin/eye contact, inhalation/ ingestion.

Corrosive.

Ethanol Hazardous in case of skin/eye contact, inhalation/ ingestion. Flammable.

Hexanes Hazardous in case of skin/eye contact, inhalation/ ingestion. Flammable.

Ethyl Acetate Hazardous in case of skin/eye contact, inhalation/ ingestion. Flammable.

Phosphomolybdic acid Hazardous in case of skin/eye contact, inhalation/ ingestion.

Toxic and corrosive. Will stain skin, wear gloves.

Waste Disposal:

Aqueous filtrate, product isolation: Acidic wasteIsolated Dichloro product: Collected in labeled bottle

Solubility Tests: Nonhalogenated organic waste

TLC mobile phase: Nonhalogenated organic waste

Pipettes: Glass waste

chem 212 - sn1 lab

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