[PDF] Reactions of alcohols in acetic anhydride-mineral acid mixtures PDF

ACETYLATION OF SUBSTITUTED BENZYL ALCOHOLS WITH ACETIC ANHYDRIDE CATALYSED BY SULPHURIC ACID A FISCHER+ M J HARDMAN M P HARTSHORN and 0 J WRIGHT

ACID CATALYSED REACTIONS OF ALCOHOLS IN ACETIC

Al&met-Acetylation of cyclohcxanol using sulphuric acid-acetic anhydride proacds O&J attack of a cyclohexanol molccuk on cydohexyl aatyl sulphate

[PDF] Reactions of alcohols in acetic anhydride-mineral acid mixtures

the acetylation of anisole by acetic anhydride and perchloric Reactions of Alcohols with Acetic Anhydride and Inorganic Acids In acetylation reactions

REACTIONS OF ALCOHOLS IN

ACETIC ANHYDRIDE-MINERAL ACID MIXTURES

A thesis presented for the

degree of Doctor of Philosophy in Chemistry in the University of Canterbury,

Christchurch, New Zealand

M.' J. ;Hardman

1967

GENERAL INTRODUCTION

• • • • • • •. • • • • • • • • e • • • • • • • • • • • • • • • • •

Equilibria between Acetic Anhydride and Inorganic Acids

Reactions of Alcohols with Acetic Anhydride and

Page 1 Inorganic Acids .. . .. .. . .. . . . . . . . . . ..... ...... .. . 8 Steroidal Alcohols -The Westphalen Rearrangement 9 PART I: REACTIONS OF ALCOHOLS WITH SULPHURIC ACID AND

ACETIC ANHYDRIDE

INTRODUCTION ......................................... .........................................

EXPERIMENTAL

Kinetics

Introduction

Theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Preparation of reagents

Experimental procedure

Calculation of results

Typical kinetic runs

Discussion of kinetic methods . . . . . . . . . . . . . . . . . . . KINETIC RESULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

MASS SPECTROMETRIC STUDIES USING o

Experimental and Results

Preparation of solvent

Experimental procedure

14 15 18 18 20 21
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Calculation of results . . . . . . . . . . . . . . . . . . . . . . . . . .

Results

DISCUSSION

Reaction of Cholestanol with Sulphuric Acid-·

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Acetic Anhydride . • . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Reaction of Cyclohexanol with Sulphuric Acid-

Acetic Anhydride ••••.•••.••.•••..•.•.•••

.••. , • • • • 7 3 Acetylation of Benzyl Alcohols . . . . . . . . . . . . . . . . . . . . 78

Reaction of 1-Methylcyclohexanol with Acetic

Anhydride-Sulphuric Acid • . • • • • • • . • . • • • • • • • • • • . • • 85

Reactions of 86

Comparison of Rates for Methylcyclohexanol and

• • • . . • . . . • • • • . . . • • . • • • • . • • • . • • 90

PART II: THE REACTION OF

WITH FLUOSULPHONIC ACID

INTRODUCTION

DISCUSSION

Structure of Hydroxy-diacetate

Structure of Olefin-diacetate

EXPERIMENTAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REFERENCES ...................................••..... 96
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ABSTRACT

The reaction of with acetic anhydride

and sulphuric acid has been studied. A kinetic investigation has been made of the reaction of these reagents with cyclohexanol, 1-methylcyclohexanol and a series of benzyl alcohols. The relative rates for the reaction of some

6p-substituted-3p-acetoxycholestan-5a-ols in this system have

been determined and the rates compared with that for

1-methylcyclohexanol.

The reaction of with

fluosulphonic acid has been shown to involve a "backbone" rearrangement terminated at a position intermediate between those usually found. The structure of one of the products has been determined and a structure is suggested for another product.

GENERAL INTRODUCTION.

Equilibria between Acetic Anhydride and Inorganic Acids. The first measurements of the acidities of various acids in acetic acid solution were carried out potentiomet- rically using chloranil 1 and hydrogen 2 electrodes. The 'd' . { )HAc f 1 b · · ac1 1t1es, pH , were ound to e greater 1n acet1c acid than in. a9ueous solutions and were enhanced 2 even more by the presence of acetic anhydride. The latter en- hancement was found to be greatest for sulphuric acid; the acidity increased markedly with increased anhydride concentration up to a certain concentration (8% Ac 2 0 for 1M HzS04) and then more gradually. This was explained by the formation of a monobasic acid, acetyl sulphate, which slowly decomposed on standing to sulphoacetic acid. Acetyl sulphate would be expected to be more acidic than sulphuric acid because of the greater stability of the anion caused by the replacement of a hydrogen atom by the electron acetyl group. Perchloric acid showed a gradual increase in acidity with increase in acetic anhydride concentration indicative of some compound formation, while the acidity of sulpha- acetic acid appeared to be practically independent of acetic anhydride concentration (addition of a further acetyl group would not give an acidic compound).

Further evidence for the suitability of mechanism

{1) to explain the behaviour of sulphuric acid-acetic anhydride mixtures came from a kinetic study 3 of the rates of formation of sulphoaliphatic acids. Mechanism (1) would predict that the rate would be dependent on the sulphuric acid concentration and the ratio of anhydride to acid. A first order dependence on sulphuric acid was found and a good linear plot of rate vs I [aci4) was found for propionic and butyric anhydrides. For acetic anhydride and acetic acid deviations from linearity found at higher anhydride concentrations were considered to be due to solvent effects.

Mackenzie and Winter studied

4 the acetylation of quinones by acetic anhydride catalysed by perchloric acid (Thiele acetylation) and found 4 a that the rate varied markedly with the ratio of acetic anhydride to acetic acid in the solvent. They measured the acidity of the solvent both by potentiometric methods to give (pH)HAc and b

· d' t · · t' 4a,b · · d' f ·

y 1n 1ca or 10n1za 1on . to g1ve an ac1 1ty unct1on 2 related to the Hammett H and found that these showed a 0 3 dependence on the Ac 2

0/AcOH ratio similar to that of the rate.

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[PDF] [PDF] Reactions of alcohols in acetic anhydride-mineral acid mixtures

acetylation of substituted benzyl alcohols with acetic anhydride

ACID CATALYSED REACTIONS OF ALCOHOLS IN ACETIC